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Sample records for singly clamped beams

  1. Theoretical and experimental nonlinear dynamics of a clamped-clamped beam MEMS resonator

    NARCIS (Netherlands)

    Mestrom, R.M.C.; Fey, R.H.B.; Nijmeijer, H.

    2008-01-01

    Microelectromechanical resonators feature nonlineardynamic responses. A first-principles based modeling approach is proposed for a clamped-clamped beam resonator. Starting from the partial differential equation for the beam including geometric and electrostatic nonlinear effects, a reduced-order

  2. Dynamic characteristics of rotating pretwisted clamped-clamped beam under thermal stress

    International Nuclear Information System (INIS)

    Zhang, Bo; Li, Yueming; Lu, Wei Zhen

    2016-01-01

    Effects of thermal stress on the vibration characteristics, buckling limit and critical speed of a rotating pretwisted beam clamped to rigid hub at a stagger angle were investigated. By considering the work done by thermal stress, the thermal influence on stiffness matrix was introduced in the dynamic model. The motion equations were derived based on Lagrange equation by employing three pure Cartesian deformation variables combined with nonlinear von Karman strain formula. Numerical investigations studied the modal characteristics of the beam. Numerical results calculated from a commercial finite element code and obtained with the present modeling method were in good agreement with the previous results reported in the literature. The combined softening effects due to the thermal stress and the rotation motion were observed. Furthermore, it is shown that the inclusion of thermal stress is necessary for blades operating under a high temperature field. Buckling thermal loads and the critical rotating speed were calculated through solving the corresponding nonlinear equations numerically, and some pertinent conclusions are outlined. It is also found that the peak value position of the first mode shape approaches to the tip of blade with the increment of rotating speed and hub radius. However, the variation in the environment temperature causes only a slight alteration in the mode shape

  3. Dynamic characteristics of rotating pretwisted clamped-clamped beam under thermal stress

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo; Li, Yueming [State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Key Laboratory of Environment and Control for Flight Vehicle, School of Aerospace, Xi' an Jiaotong UniversityXi' an (China); Lu, Wei Zhen [Dept. of Civil and Architectural Engineering, City University of Hong Kong, Hong Kong (China)

    2016-09-15

    Effects of thermal stress on the vibration characteristics, buckling limit and critical speed of a rotating pretwisted beam clamped to rigid hub at a stagger angle were investigated. By considering the work done by thermal stress, the thermal influence on stiffness matrix was introduced in the dynamic model. The motion equations were derived based on Lagrange equation by employing three pure Cartesian deformation variables combined with nonlinear von Karman strain formula. Numerical investigations studied the modal characteristics of the beam. Numerical results calculated from a commercial finite element code and obtained with the present modeling method were in good agreement with the previous results reported in the literature. The combined softening effects due to the thermal stress and the rotation motion were observed. Furthermore, it is shown that the inclusion of thermal stress is necessary for blades operating under a high temperature field. Buckling thermal loads and the critical rotating speed were calculated through solving the corresponding nonlinear equations numerically, and some pertinent conclusions are outlined. It is also found that the peak value position of the first mode shape approaches to the tip of blade with the increment of rotating speed and hub radius. However, the variation in the environment temperature causes only a slight alteration in the mode shape.

  4. A CMOS-MEMS clamped–clamped beam displacement amplifier for resonant switch applications

    Science.gov (United States)

    Liu, Jia-Ren; Lu, Shih-Chuan; Tsai, Chun-Pu; Li, Wei-Chang

    2018-06-01

    This paper presents a micromechanical clamped–clamped beam (CC-beam) displacement amplifier based on a CMOS-MEMS fabrication process platform. In particular, a 2.0 MHz resonant displacement amplifier composed of two identical CC-beams coupled by a mechanical beam at locations where the two beams have mismatched velocities exhibits a larger displacement, up to 9.96×, on one beam than that of the other. The displacement amplification prevents unwanted input impacting—the structure switches only to the output but not the input—required by resonant switch-based mechanical circuits (Kim et al 2009 22nd IEEE Int. Conf. on Micro Electro Mechanical Systems; Lin et al 2009 15th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’09) Li et al 2013 17th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’13)). Compared to a single CC-beam displacement amplifier, theory predicts that the displacement amplifying CC-beam array yields a larger overall output displacement for displacement gain beyond 1.13 thanks to the preserved input driving force. A complete analytical model predicts the resultant stiffness and displacement gain of the coupled CC-beam displacement amplifier that match well with finite element analysis (FEA) prediction and measured results.

  5. Single Beam Holography.

    Science.gov (United States)

    Chen, Hsuan; Ruterbusch, Paul H.

    1979-01-01

    Discusses how holography can be used as part of undergraduate physics laboratories. The authors propose a single beam technique of holography, which will reduce the recording scheme as well as relax the isolation requirements. (HM)

  6. Mechanical nonlinearity elimination with a micromechanical clamped-free semicircular beams resonator

    Science.gov (United States)

    Chen, Dongyang; Chen, Xuying; Wang, Yong; Liu, Xinxin; Guan, Yangyang; Xie, Jin

    2018-04-01

    This paper reports a micro-machined clamped-free semicircular beam resonator aiming to eliminate the nonlinearity that widely exists in traditional mechanical resonators. Cubic coefficients over vibration displacement due to axial extension of the beams are analyzed through theoretical modelling, and the corresponding frequency effect is demonstrated. With the device working in the elastic vibration mode, the cubic coefficients are eliminated by using a free end to release the nonlinear extension of beams and thus the inside axial stress. The amplitude-frequency (A-f) effect is overcome in a large region of source power, and the coefficient of frequency softening is linearized in a large region of polarization voltage. As a result, the resonator can be driven at larger vibration amplitude to achieve a high signal to noise ratio and power handling performance.

  7. Boundary discontinuous Fourier analysis of thick beams with clamped and simply supported edges via CUF

    Directory of Open Access Journals (Sweden)

    F.G. CANALES

    2017-10-01

    Full Text Available This paper presents an analytical solution for static analysis of thick rectangular beams with different boundary conditions. Carrera’s Unified Formulation (CUF is used in order to consider shear deformation theories of arbitrary order. The novelty of the present work is that a boundary discontinuous Fourier approach is used to consider clamped boundary conditions in the analytical solution, unlike Navier-type solutions which are restricted to simply supported beams. Governing equations are obtained by employing the principle of virtual work. The numerical accuracy of results is ascertained by studying the convergence of the solution and comparing the results to those of a 3D finite element solution. Beams subjected to bending due to a uniform pressure load and subjected to torsion due to opposite linear forces are considered. Overall, accurate results close to those of 3D finite element solutions are obtained, which can be used to validate finite element results or other approximate methods.

  8. Single base pair mutation analysis by PNA directed PCR clamping

    DEFF Research Database (Denmark)

    Ørum, H.; Nielsen, P.E.; Egholm, M.

    1993-01-01

    A novel method that allows direct analysis of single base mutation by the polymerase chain reaction (PCR) is described. The method utilizes the finding that PNAs (peptide nucleic acids) recognize and bind to their complementary nucleic acid sequences with higher thermal stability and specificity...... allows selective amplification/suppression of target sequences that differ by only one base pair. Finally we show that PNAs can be designed in such a way that blockage can be accomplished when the PNA target sequence is located between the PCR primers....

  9. Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

    Science.gov (United States)

    He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

    2018-05-01

    A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

  10. Adjustable static and dynamic actuation of clamped-guided beams using electrothermal axial loads

    KAUST Repository

    Alcheikh, Nouha

    2018-02-14

    The paper presents adjustable static and dynamic actuations of in-plane clamped-guided beams. The structures, of variable stiffness, can be used as highly tunable resonators and actuators. Axial loads are applied through electrothermal U-shaped and flexure beams actuators stacked near the edges of curved (arch) beams. The electrothermal actuators can be configurred in various ways to adjust as desired the mechanical stiffness of the structures; thereby controlling their deformation stroke as actuators and their operating resonance frequency as resonators. The experimental and finite element results demonstrate the flexibility of the designs in terms of static displacements and resonance frequencies of the first and second symmetric modes of the arches. The results show considerable increase in the resonance frequency and deflection of the microbeam upon changing end actuation conditions, which can be promising for low voltage actuation and tunable resonators applications, such as filters and memory devices. As case studies of potential device configurations of the proposed design, we demonstrate eight possibilities of achieving new static and dynamic behaviors, which produce various resonance frequencies and static displacement curves. The ability to actively shift the entire frequency response curve of a device is desirable for several applications to compensate for in-use anchor degradations and deformations. As an example, we experimentally demonstrate using the device as a resonant logic gate, with active resonance tuning, showing fundamental 2-bit logic functions, such as AND,XOR, and NOR.

  11. Adjustable static and dynamic actuation of clamped-guided beams using electrothermal axial loads

    KAUST Repository

    Alcheikh, Nouha; Tella, Sherif Adekunle; Younis, Mohammad I.

    2018-01-01

    The paper presents adjustable static and dynamic actuations of in-plane clamped-guided beams. The structures, of variable stiffness, can be used as highly tunable resonators and actuators. Axial loads are applied through electrothermal U-shaped and flexure beams actuators stacked near the edges of curved (arch) beams. The electrothermal actuators can be configurred in various ways to adjust as desired the mechanical stiffness of the structures; thereby controlling their deformation stroke as actuators and their operating resonance frequency as resonators. The experimental and finite element results demonstrate the flexibility of the designs in terms of static displacements and resonance frequencies of the first and second symmetric modes of the arches. The results show considerable increase in the resonance frequency and deflection of the microbeam upon changing end actuation conditions, which can be promising for low voltage actuation and tunable resonators applications, such as filters and memory devices. As case studies of potential device configurations of the proposed design, we demonstrate eight possibilities of achieving new static and dynamic behaviors, which produce various resonance frequencies and static displacement curves. The ability to actively shift the entire frequency response curve of a device is desirable for several applications to compensate for in-use anchor degradations and deformations. As an example, we experimentally demonstrate using the device as a resonant logic gate, with active resonance tuning, showing fundamental 2-bit logic functions, such as AND,XOR, and NOR.

  12. Active vibration control of clamped beams using positive position feedback controllers with moment pair

    International Nuclear Information System (INIS)

    Shin, Chang Joo; Jeong, Weui Bong; Hong, Chin Suk

    2012-01-01

    This paper investigates the active vibration control of clamp beams using positive position feedback (PPF) controllers with a sensor/ moment pair actuator. The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control. To alleviate the instability problem, a PPF controller is considered in this paper. A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance. The gain of the controller is found to affect only the relative stability. Increasing the damping ratio of the controller slightly improves the stability condition while the performance gets worse. In addition, the higher mode tuned PPF controller affects the system response at the lower modes significantly. Based on the characteristics of PPF controllers, a multi-mode controllable SISO PPF controller is then considered and tuned to different modes (in this case, three lowest modes) numerically and experimentally. The multi-mode PPF controller can be achieved to have a high gain margin. Moreover, it reduces the vibration of the beam significantly. The vibration levels at the tuned modes are reduced by about 11 dB

  13. Analysis of failed and nickel-coated 3093 beam clamp components at the East Tennessee Technology Park (ETTP).

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.; Pappacena, K.; Gaviria, J.; Burtsteva, T.; Nuclear Engineering Division

    2010-10-11

    The U.S. Department of Energy and its contractor, Bechtel Jacobs Company (BJC), are undertaking a major effort to clean up the former gaseous diffusion facility (K-25) located in Oak Ridge, TN. The decontamination and decommissioning activities require systematic removal of contaminated equipment and machinery followed by demolition of the buildings. As part of the cleanup activities, a beam clamp, used for horizontal life lines (HLLs) for fall protection, was discovered to be fractured during routine inspection. The beam clamp (yoke and D-ring) was a component in the HLL system purchased from Reliance Industries LLC. Specifically, the U-shaped stainless steel yoke of the beam clamp failed in a brittle mode at under less than 10% of the rated design capacity of 14,500 lb. The beam clamp had been in service for approximately 16 months. Bechtel Jacobs approached Argonne National Laboratory to assist in identifying the root cause of the failure of the beam clamp. The objectives of this study were to (1) review the prior reports and documents on the subject, (2) understand the possible failure mechanism(s) that resulted in the failed beam clamp components, (3) recommend approaches to mitigate the failure mechanism(s), and (4) evaluate the modified beam clamp assemblies. Energy dispersive x-ray analysis and chemical analysis of the corrosion products on the failed yoke and white residue on an in-service yoke indicated the presence of zinc, sulfur, and calcium. Analysis of rainwater in the complex, as conducted by BJC, indicated the presence of sulfur and calcium. It was concluded that, as a result of galvanic corrosion, zinc from the galvanized components of the beam clamp assembly (D-ring) migrated to the corroded region in the presence of the rainwater. Under mechanical stress, the corrosion process would have accelerated, resulting in the catastrophic failure of the yoke. As suggested by Bechtel Jacobs personnel, hydrogen embrittlement as a consequence of corrosion

  14. Single aortic clamping in coronary artery bypass surgery reduces cerebral embolism and improves neurocognitive outcomes.

    Science.gov (United States)

    Gasparovic, Hrvoje; Borojevic, Marko; Malojcic, Branko; Gasparovic, Kristina; Biocina, Bojan

    2013-10-01

    Aortic manipulation releases embolic material, thereby enhancing the probability of adverse neurologic outcomes following coronary artery bypass grafting (CABG). We prospectively evaluated 59 patients undergoing CABG. Patients in the single (SC, n = 37) and multiple clamp (MC, n = 22) groups were comparable in relation to age and operative risk (p > 0.05). Neurocognitive evaluation consisted of the Auditory Verbal Learning Test (AVLT), Color Trails Test A, the Grooved Pegboard test and the Mini-Mental State Examination. Data acquisition was performed preoperatively, early postoperatively and at the 4-month follow-up. Intraoperative transcranial Doppler (TCD) monitoring was used to quantify the embolic load in relation to different aortic clamping strategies. Preoperative neurocognitive results were similar between the groups (p > 0.05). The incidence of postoperative delirium was greater in the MC group but this failed to reach statistical significance (23% vs 8%, p = 0.14). SC patients had fewer embolization signals (270 ± 181 vs 465 ± 160, p cognitive depression was greater in the MC group (p cognition deficits and superior late restoration of function.

  15. Single lens laser beam shaper

    Science.gov (United States)

    Liu, Chuyu [Newport News, VA; Zhang, Shukui [Yorktown, VA

    2011-10-04

    A single lens bullet-shaped laser beam shaper capable of redistributing an arbitrary beam profile into any desired output profile comprising a unitary lens comprising: a convex front input surface defining a focal point and a flat output portion at the focal point; and b) a cylindrical core portion having a flat input surface coincident with the flat output portion of the first input portion at the focal point and a convex rear output surface remote from the convex front input surface.

  16. Single stage buck-boost DC-AC neutral point clamped inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Andrew, A.

    2012-01-01

    This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence......, it has enhanced buck-boost functionality and low output voltage distortions compared to the traditional Z-source inverter; it has continuous input current which reduces the source stress and inverter noise; it also contains two built-in capacitors which can block the DC current in the transformer...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...

  17. Analytical study of the frequency shifts of micro and nano clamped–clamped beam resonators due to an added mass

    KAUST Repository

    Bouchaala, Adam M.

    2016-03-18

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped–clamped micro and nano (Carbon nanotube) beams due to an added mass. Based on the Euler–Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes. © 2016 Springer Science+Business Media Dordrecht

  18. High performance control strategy for single-phase three-level neutral-point-clamped traction four-quadrant converters

    DEFF Research Database (Denmark)

    Kejian, Song; Konstantinou, Georgios; Jing, Li

    2017-01-01

    Operational data from Chinese railways indicate a number of challenges for traction four-quadrant converter (4QC) control including low-order voltage and current harmonics and reference tracking. A control strategy for a single-phase three-level neutral-point-clamped 4QC employed in the electric...

  19. Impedance spectra of patch clamp scenarios for single cells immobilized on a lab-on-a-chip

    DEFF Research Database (Denmark)

    Alberti, Massimo; Snakenborg, Detlef; Lopacinska, Joanna M.

    2014-01-01

    and simulated impedance spectra proved that the presented method could distinguish between a cell-attached mode and a whole-cell mode even with low-quality seals. In physiological conditions, the capacitance of HeLa cells was measured to *38 pF. The first gigaseal was recorded and maintained for 40 min. Once...... membrane. After incubating the chip for 24 h, HeLa cells adhered and grew on the chip surface but did not survive when trapped on the microapertures. The microfluidic system proved to work as a micro electrophysiological analysis system, and the IS-based method can be used for further studies on the post......A simple method based on impedance spectroscopy (IS) was developed to distinguish between different patch clamp modes for single cells trapped on microapertures in a patch clamp microchannel array designed for patch clamping on cultured cells. The method allows detecting via impedance analysis...

  20. Comparison between symmetrical and asymmetrical single phase multilevel inverter with diode-clamped topology

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Nami, A.; Zare, F.

    2008-01-01

    In this paper, a different configuration based on different DC bus voltage for a diode-clamped multilevel inverter has been presented. Two different symmetrical and asymmetrical arrangements of a four-level diode clamped inverters have been compared, in order to find an optimum arrangement...... compared with the conventional four-level inverter and this will lead to the reduction of harmonic content of output voltage. A predictive current control technique has been carried out to verify the viability of new configuration. The advantages of this control method are simplicity and applicability...

  1. Clamped elastic-ideally plastic beams and Prandtl-Ishlinskii hysteresis operators

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel; Sprekels, J.

    2008-01-01

    Roč. 1, č. 2 (2008), s. 283-292 ISSN 1937-1632 Institutional research plan: CEZ:AV0Z10190503 Keywords : elastoplasticity * beam equation * hysteresis Subject RIV: BA - General Mathematics http://aimsciences.org/journals/pdfs.jsp?paperID=3201&mode=abstract

  2. Closed-form solution for static pull-in voltage of electrostatically actuated clamped-clamped micro/nano beams under the effect of fringing field and van der Waals force

    Science.gov (United States)

    Bhojawala, V. M.; Vakharia, D. P.

    2017-12-01

    This investigation provides an accurate prediction of static pull-in voltage for clamped-clamped micro/nano beams based on distributed model. The Euler-Bernoulli beam theory is used adapting geometric non-linearity of beam, internal (residual) stress, van der Waals force, distributed electrostatic force and fringing field effects for deriving governing differential equation. The Galerkin discretisation method is used to make reduced-order model of the governing differential equation. A regime plot is presented in the current work for determining the number of modes required in reduced-order model to obtain completely converged pull-in voltage for micro/nano beams. A closed-form relation is developed based on the relationship obtained from curve fitting of pull-in instability plots and subsequent non-linear regression for the proposed relation. The output of regression analysis provides Chi-square (χ 2) tolerance value equals to 1  ×  10-9, adjusted R-square value equals to 0.999 29 and P-value equals to zero, these statistical parameters indicate the convergence of non-linear fit, accuracy of fitted data and significance of the proposed model respectively. The closed-form equation is validated using available data of experimental and numerical results. The relative maximum error of 4.08% in comparison to several available experimental and numerical data proves the reliability of the proposed closed-form equation.

  3. Single bunched beam generation without subharmonic prebuncher

    International Nuclear Information System (INIS)

    Kobayashi, T.; Tagawa, S.

    1995-01-01

    The intensity of the accelerated single bunched electron beam depends on the performance of the electron gun and the fast cathode pulser. The electron beam is emitted by a Y-796 cathode assembly with a cathode of 2 cm 2 (8 A/cm 2 ), and an extracted voltage of 90 kV. The maximum charge of the single bunched beam was attained at 1.5 nC/pulse using SHB. Recently, a single bunched beam has been generated by an ultrafast cathode pulser (rise and fall time <100 ps pulse height -2 kV at 50 Ω) without SHB. The charge of the accelerated electron beam is about 40 pC/pulse (pulse width <10 ps) without the production of a satellite beam. This result show that a single bunched beam can be produced by the linear accelerator without SHB. ((orig.))

  4. J-integral analysis of heterogeneous mismatched girth welds in clamped single-edge notched tension specimens

    International Nuclear Information System (INIS)

    Hertelé, Stijn; De Waele, Wim; Verstraete, Matthias; Denys, Rudi; O'Dowd, Noel

    2014-01-01

    Flaw assessment procedures require a quantification of crack driving force, and such procedures are generally based on the assumption of weld homogeneity. However, welds generally have a heterogeneous microstructure, which will influence the crack driving force. This paper describes a stress-based methodology to assess complex heterogeneous welds using a J-based approach. Clamped single-edge notched tension specimens, representative of girth weld flaws, are analyzed and the influence of weld heterogeneity on crack driving force has been determined. The use of a modified limit load for heterogeneous welds is proposed, suitable for implementation in a ‘homogenized’ J-integral estimation scheme. It follows from an explicit modification of an existing solution for centre cracked tension specimens. The proposed solution provides a good estimate of crack driving force and any errors in the approximation may be accounted for by means of a small safety factor on load bearing capacity. - Highlights: • We present a crack driving force estimation procedure for heterogeneous welds. • The procedure is based on a ‘homogenized’ version of the EPRI equation. • Complex welds are translated into equivalent idealized mismatched welds. • The procedure is validated for clamped SE(T) specimens. • A mismatch limit load for clamped SE(T) specimens is developed

  5. Single-Carrier Modulation for Neutral-Point-Clamped Inverters in Three-Phase Transformerless Photovoltaic Systems

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Cavalcanti, Marcelo C.; Farias, Alexandre M.

    2013-01-01

    Modulation strategy is one of the most important issues for three-level neutral-point-clamped inverters in three-phase transformerless photovoltaic systems. A challenge for modulation is how to keep the common-mode voltages constant to reduce the leakage currents. A single-carrier modulation...... strategy is proposed. It has a very simple structure, and the common-mode voltages can be kept constant with no need of complex space-vector modulation or multicarrier pulsewidth modulation. Experimental results verify the theoretical analysis and the effectiveness of the presented method....

  6. High Performance ZVT with Bus Clamping Modulation Technique for Single Phase Full Bridge Inverters

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yinglai; Ayyanar, Raja

    2016-03-20

    This paper proposes a topology based on bus clamping modulation and zero-voltage-transition (ZVT) technique to realize zero-voltage-switching (ZVS) for all the main switches of the full bridge inverters, and inherent ZVS and/or ZCS for the auxiliary switches. The advantages of the strategy include significant reduction in the turn-on loss of the ZVT auxiliary switches which typically account for a major part of the total loss in other ZVT circuits, and reduction in the voltage ratings of auxiliary switches. The modulation scheme and the commutation stages are analyzed in detail. Finally, a 1kW, 500 kHz switching frequency inverter of the proposed topology using SiC MOSFETs has been built to validate the theoretical analysis. The ZVT with bus clamping modulation technique of fixed timing and adaptive timing schemes are implemented in DSP TMS320F28335 resulting in full ZVS for the main switches in the full bridge inverter. The proposed scheme can save up to 33 % of the switching loss compared with no ZVT case.

  7. Accurate electrostatic and van der Waals pull-in prediction for fully clamped nano/micro-beams using linear universal graphs of pull-in instability

    Science.gov (United States)

    Tahani, Masoud; Askari, Amir R.

    2014-09-01

    In spite of the fact that pull-in instability of electrically actuated nano/micro-beams has been investigated by many researchers to date, no explicit formula has been presented yet which can predict pull-in voltage based on a geometrically non-linear and distributed parameter model. The objective of present paper is to introduce a simple and accurate formula to predict this value for a fully clamped electrostatically actuated nano/micro-beam. To this end, a non-linear Euler-Bernoulli beam model is employed, which accounts for the axial residual stress, geometric non-linearity of mid-plane stretching, distributed electrostatic force and the van der Waals (vdW) attraction. The non-linear boundary value governing equation of equilibrium is non-dimensionalized and solved iteratively through single-term Galerkin based reduced order model (ROM). The solutions are validated thorough direct comparison with experimental and other existing results reported in previous studies. Pull-in instability under electrical and vdW loads are also investigated using universal graphs. Based on the results of these graphs, non-dimensional pull-in and vdW parameters, which are defined in the text, vary linearly versus the other dimensionless parameters of the problem. Using this fact, some linear equations are presented to predict pull-in voltage, the maximum allowable length, the so-called detachment length, and the minimum allowable gap for a nano/micro-system. These linear equations are also reduced to a couple of universal pull-in formulas for systems with small initial gap. The accuracy of the universal pull-in formulas are also validated by comparing its results with available experimental and some previous geometric linear and closed-form findings published in the literature.

  8. Investigation of sliding DNA clamp dynamics by single-molecule fluorescence, mass spectrometry and structure-based modeling

    Science.gov (United States)

    Gadkari, Varun V; Harvey, Sophie R; Raper, Austin T; Chu, Wen-Ting; Wang, Jin; Wysocki, Vicki H; Suo, Zucai

    2018-01-01

    Abstract Proliferating cell nuclear antigen (PCNA) is a trimeric ring-shaped clamp protein that encircles DNA and interacts with many proteins involved in DNA replication and repair. Despite extensive structural work to characterize the monomeric, dimeric, and trimeric forms of PCNA alone and in complex with interacting proteins, no structure of PCNA in a ring-open conformation has been published. Here, we use a multidisciplinary approach, including single-molecule Förster resonance energy transfer (smFRET), native ion mobility-mass spectrometry (IM-MS), and structure-based computational modeling, to explore the conformational dynamics of a model PCNA from Sulfolobus solfataricus (Sso), an archaeon. We found that Sso PCNA samples ring-open and ring-closed conformations even in the absence of its clamp loader complex, replication factor C, and transition to the ring-open conformation is modulated by the ionic strength of the solution. The IM-MS results corroborate the smFRET findings suggesting that PCNA dynamics are maintained in the gas phase and further establishing IM-MS as a reliable strategy to investigate macromolecular motions. Our molecular dynamic simulations agree with the experimental data and reveal that ring-open PCNA often adopts an out-of-plane left-hand geometry. Collectively, these results implore future studies to define the roles of PCNA dynamics in DNA loading and other PCNA-mediated interactions. PMID:29529283

  9. Single beam stability, incoherent effects

    International Nuclear Information System (INIS)

    Autin, B.; Bassetti, M.; Faugeras, P.; Hilaire, A.; Montague, B.; Potaux, D.; Scandale, W.; Vos, L.; Zyngier, H.

    1980-01-01

    The group first realized that it was difficult in the available time to make an overall review of the many subjects implied by the group's heading. It therefore restricted itself to a few separate topics, which are: 1. Working point. 2. Non-linear coupling. 3. Effect of octupoles. 4. Chromaticity correction and tracking. 5. Vertical dispersion. 6. Beam separation. 7. Remark on non-linear lens experiments. (orig.)

  10. Dynamic Pull-In Investigation of a Clamped-Clamped Nanoelectromechanical Beam under Ramp-Input Voltage and the Casimir Force

    Directory of Open Access Journals (Sweden)

    Amir R. Askari

    2014-01-01

    Full Text Available The influence of the Casimir excitation on dynamic pull-in instability of a nanoelectromechanical beam under ramp-input voltage is studied. The ramp-input actuation has applications in frequency sweeping of RF-N/MEMS. The presented model is nonlinear due to the inherent nonlinearity of electrostatics and the Casimir excitations as well as the geometric nonlinearity of midplane stretching. A Galerkin based reduced order modeling is utilized. It is found that the calculated dynamic pull-in ramp input voltage leads to dynamic pull-in step input voltage by increasing the slope of voltage-time diagram. This fact is utilized to verify the results of present study.

  11. Voltage-Sharing Converter to Supply Single-Phase Asymmetrical Four-Level Diode-Clamped Inverter With High Power Factor Loads

    DEFF Research Database (Denmark)

    Boora, Arash A.; Nami, Alireza; Zare, Firuz

    2010-01-01

    The output voltage quality of some of the single-phase multilevel inverters can be improved when their dc-link voltages are regulated asymmetrically. Symmetrical and asymmetrical multilevel diode-clamped inverters have the problem of dc-link capacitor voltage balancing, especially when power factor...... that the proposed combination of introduced multioutput dc–dc converter and single-phase ADCI is a good candidate for power conversion in residential photovoltaic (PV) utilization....

  12. DC dynamic pull-in predictions for a generalized clamped–clamped micro-beam based on a continuous model and bifurcation analysis

    International Nuclear Information System (INIS)

    Chao, Paul C-P; Chiu, C W; Liu, Tsu-Hsien

    2008-01-01

    This study is devoted to providing precise predictions of the dc dynamic pull-in voltages of a clamped–clamped micro-beam based on a continuous model. A pull-in phenomenon occurs when the electrostatic force on the micro-beam exceeds the elastic restoring force exerted by beam deformation, leading to contact between the actuated beam and bottom electrode. DC dynamic pull-in means that an instantaneous application of the voltage (a step function such as voltage) is applied. To derive the pull-in voltage, a dynamic model in partial differential equations is established based on the equilibrium among beam flexibility, inertia, residual stress, squeeze film, distributed electrostatic forces and its electrical field fringing effects. The method of Galerkin decomposition is then employed to convert the established system equations into reduced discrete modal equations. Considering lower-order modes and approximating the beam deflection by a different order series, bifurcation based on phase portraits is conducted to derive static and dynamic pull-in voltages. It is found that the static pull-in phenomenon follows dynamic instabilities, and the dc dynamic pull-in voltage is around 91–92% of the static counterpart. However, the derived dynamic pull-in voltage is found to be dependent on the varied beam parameters, different from a fixed predicted value derived in past works, where only lumped models are assumed. Furthermore, accurate closed-form predictions are provided for non-narrow beams. The predictions are finally validated by finite element analysis and available experimental data

  13. Single beam pass migmacell method and apparatus

    International Nuclear Information System (INIS)

    Maglich, B.C.; Nering, J.E.; Mazarakis, M.G.; Miller, R.A.

    1976-01-01

    The invention provides improvements in migmacell apparatus and method by dispensing with the need for metastable confinement of injected molecular ions for multiple precession periods. Injected molecular ions undergo a 'single pass' through the reaction volume. By preconditioning the injected beam such that it contains a population distribution of molecules in higher vibrational states than in the case of a normal distribution, injected molecules in the single pass exper-ience collisionless dissociation in the migmacell under magnetic influence, i.e., so-called Lorentz dissociation. Dissociationions then form atomic migma

  14. del Nido versus St. Thomas Cardioplegia Solutions: A Single-Center Retrospective Analysis of Post Cross-Clamp Defibrillation Rates.

    Science.gov (United States)

    Buel, Shane T; Striker, Carrie Whittaker; O'Brien, James E

    2016-06-01

    There are many cardioplegia solutions currently in use for pediatric cardiopulmonary bypass (CPB). The most common being del Nido solution. Another common cardioplegia solution used for pediatric CPB is St. Thomas. In October 2014, Children's Mercy Kansas City changed from the use of modified St. Thomas to del Nido. This study compared rates of post cross-clamp fibrillation requiring defibrillation between del Nido solution and modified St. Thomas solution stratified by weight at Children's Mercy Kansas City. This retrospective study consisted of 394 patients who underwent cardiac surgery requiring cardioplegia between January 1, 2014 and July 31, 2015. The outcome measured was defibrillation upon cross-clamp removal. Statistical significance was determined using Fishers exact test with a two-sided significance level of .05. Incidence of defibrillation post cross-clamp removal was 4.4% in the del Nido group and 26.8% in the St. Thomas group (p Thomas group (p Thomas group (p Thomas group (p 60-kg category had an incidence of defibrillation of 16.7% in the del Nido group and 63% in the St. Thomas group (p Thomas and del Nido cardioplegia solutions. Analyses of weight stratifications demonstrate a decrease in the rate of defibrillation post cross-clamp removal in all categories within the del Nido group.

  15. Self triggered single pulse beam position monitor

    International Nuclear Information System (INIS)

    Rothman, J.L.; Blum, E.B.

    1993-01-01

    A self triggered beam position monitor (BPM) has been developed for the NSLS injection system to provide single pulse orbit measurements in the booster synchrotron, linac, and transport lines. The BPM integrates the negative going portion of 3 nS wide bipolar pickup electrode signals. The gated, self triggering feature confines critical timing components to the front end, relaxing external timing specifications. The system features a low noise high speed FET sampler, a fiber optic gate for bunch and turn selection, and an inexpensive interface to a standard PC data acquisition system

  16. Loading dynamics of a sliding DNA clamp.

    KAUST Repository

    Cho, Won-Ki

    2014-05-22

    Sliding DNA clamps are loaded at a ss/dsDNA junction by a clamp loader that depends on ATP binding for clamp opening. Sequential ATP hydrolysis results in closure of the clamp so that it completely encircles and diffuses on dsDNA. We followed events during loading of an E. coli β clamp in real time by using single-molecule FRET (smFRET). Three successive FRET states were retained for 0.3 s, 0.7 s, and 9 min: Hydrolysis of the first ATP molecule by the γ clamp loader resulted in closure of the clamp in 0.3 s, and after 0.7 s in the closed conformation, the clamp was released to diffuse on the dsDNA for at least 9 min. An additional single-molecule polarization study revealed that the interfacial domain of the clamp rotated in plane by approximately 8° during clamp closure. The single-molecule polarization and FRET studies thus revealed the real-time dynamics of the ATP-hydrolysis-dependent 3D conformational change of the β clamp during loading at a ss/dsDNA junction.

  17. Laparoscopic Non-clamping Tumor Enucleation of Renal Hilum Schwannoma in a Single Kidney: A Case Report

    Directory of Open Access Journals (Sweden)

    Fuminari Hanashima

    2015-11-01

    Full Text Available A 56-year-old woman underwent laparoscopic right nephrectomy due to pyonephrosis associated with right ureteral stones. Moreover, the patient developed a brain stem hemorrhage and became bedridden. At the time of nephrectomy, a renal tumor, with a size of 24 × 24 × 20 mm, was observed in the left renal hilum; the tumor did not show contrast enhancement on computed tomography. After 3 years, the tumor gradually grew to a size of 45 × 35 × 34 mm, and therefore, laparoscopic non-clamping tumor enucleation was performed. Pathological examination confirmed a diagnosis of renal schwannoma.

  18. Absolute beam-charge measurement for single-bunch electron beams

    International Nuclear Information System (INIS)

    Suwada, Tsuyoshi; Ohsawa, Satoshi; Furukawa, Kazuro; Akasaka, Nobumasa

    2000-01-01

    The absolute beam charge of a single-bunch electron beam with a pulse width of 10 ps and that of a short-pulsed electron beam with a pulse width of 1 ns were measured with a Faraday cup in a beam test for the KEK B-Factory (KEKB) injector linac. It is strongly desired to obtain a precise beam-injection rate to the KEKB rings, and to estimate the amount of beam loss. A wall-current monitor was also recalibrated within an error of ±2%. This report describes the new results for an absolute beam-charge measurement for single-bunch and short-pulsed electron beams, and recalibration of the wall-current monitors in detail. (author)

  19. Single-particle beam dynamics in Boomerang

    International Nuclear Information System (INIS)

    Jackson, Alan; Nishimura, Hiroshi

    2003-01-01

    We describe simulations of the beam dynamics in the storage ring (Boomerang), a 3-GeV third-generation light source being designed for the Australian Synchrotron Project[1]. The simulations were performed with the code Goemon[2]. They form the basis for design specifications for storage ring components (apertures, alignment tolerances, magnet quality, etc.), and for determining performance characteristics such as coupling and beam lifetime

  20. Photovoltaic panel clamp

    Science.gov (United States)

    Mittan, Margaret Birmingham [Oakland, CA; Miros, Robert H. J. [Fairfax, CA; Brown, Malcolm P [San Francisco, CA; Stancel, Robert [Loss Altos Hills, CA

    2012-06-05

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  1. Design of a multi beam klystron cavity from its single beam parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Deepender, E-mail: dkc@ceeri.ernet.in; Joshi, L. M. [CSIR-Central Electronics Engineering Research Institute, Pilani (India); Janyani, Vijay [Department of ECE, MNIT, Jaipur (India)

    2016-03-09

    The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.

  2. Design of a multi beam klystron cavity from its single beam parameters

    International Nuclear Information System (INIS)

    Kant, Deepender; Joshi, L. M.; Janyani, Vijay

    2016-01-01

    The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.

  3. Loading dynamics of a sliding DNA clamp.

    KAUST Repository

    Cho, Won-Ki; Jergic, Slobodan; Kim, Daehyung; Dixon, Nicholas E; Lee, Jong-Bong

    2014-01-01

    8° during clamp closure. The single-molecule polarization and FRET studies thus revealed the real-time dynamics of the ATP-hydrolysis-dependent 3D conformational change of the β clamp during loading at a ss/dsDNA junction.

  4. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized

  5. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. 5 refs

  6. Radial wedge flange clamp

    Science.gov (United States)

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  7. Cardiac single-photon emission-computed tomography using combined cone-beam/fan-beam collimation

    International Nuclear Information System (INIS)

    Gullberg, Grant T.; Zeng, Gengsheng L.

    2004-01-01

    The objective of this work is to increase system sensitivity in cardiac single-photon emission-computed tomography (SPECT) studies without increasing patient imaging time. For imaging the heart, convergent collimation offers the potential of increased sensitivity over that of parallel-hole collimation. However, if a cone-beam collimated gamma camera is rotated in a planar orbit, the projection data obtained are not complete. Two cone-beam collimators and one fan-beam collimator are used with a three-detector SPECT system. The combined cone-beam/fan-beam collimation provides a complete set of data for image reconstruction. The imaging geometry is evaluated using data acquired from phantom and patient studies. For the Jaszazck cardiac torso phantom experiment, the combined cone-beam/fan-beam collimation provided 1.7 times greater sensitivity than standard parallel-hole collimation (low-energy high-resolution collimators). Also, phantom and patient comparison studies showed improved image quality. The combined cone-beam/fan-beam imaging geometry with appropriate weighting of the two data sets provides improved system sensitivity while measuring sufficient data for artifact free cardiac images

  8. Behavioral changes induced by single and multiple electron beam pulses

    International Nuclear Information System (INIS)

    Pease, V.P.; McNulty, P.J.

    1985-01-01

    The effects of single, and low-dose, high-dose-rate and multiple electron beam pulses on passive avoidance behavior in mice were studied. Passive avoidance was measured by recording the time that an animal took to enter a chamber from a narrow platform. There were four conditions in the experiment: (1) no shock no radiation-control, (2) radiation only, (3) shock only, and (4) radiation plus shock. Forty animals were run for each data point. Dose rate was held constant at 9 x 10/sup 7/ rads/sec. Average doses for the two single pulses were 7.18 and 8.72 rads. The average total dose for a 25 pulse per second condition was 324.0 rads. The differences between the single versus multiple pulse radiation-only conditions were significant with longer avoidance latencies in the multiple pulse condition. Avoidance latencies were also significantly longer in the shock plus radiation condition for the multiple beam pulse than the single pulse. It is concluded that single and multiple electron beam pulses significantly effect behavior, in this case producing avoidance

  9. Single beam Fourier transform digital holographic quantitative phase microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anand, A., E-mail: arun-nair-in@yahoo.com; Chhaniwal, V. K.; Mahajan, S.; Trivedi, V. [Optics Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001 (India); Faridian, A.; Pedrini, G.; Osten, W. [Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart (Germany); Dubey, S. K. [Siemens Technology and Services Pvt. Ltd, Corporate Technology—Research and Technology Centre, Bangalore 560100 (India); Javidi, B. [Department of Electrical and Computer Engineering, U-4157, University of Connecticut, Storrs, Connecticut 06269-2157 (United States)

    2014-03-10

    Quantitative phase contrast microscopy reveals thickness or height information of a biological or technical micro-object under investigation. The information obtained from this process provides a means to study their dynamics. Digital holographic (DH) microscopy is one of the most used, state of the art single-shot quantitative techniques for three dimensional imaging of living cells. Conventional off axis DH microscopy directly provides phase contrast images of the objects. However, this process requires two separate beams and their ratio adjustment for high contrast interference fringes. Also the use of two separate beams may make the system more vulnerable to vibrations. Single beam techniques can overcome these hurdles while remaining compact as well. Here, we describe the development of a single beam DH microscope providing whole field imaging of micro-objects. A hologram of the magnified object projected on to a diffuser co-located with a pinhole is recorded with the use of a commercially available diode laser and an arrayed sensor. A Fourier transform of the recorded hologram directly yields the complex amplitude at the image plane. The method proposed was investigated using various phase objects. It was also used to image the dynamics of human red blood cells in which sub-micrometer level thickness variation were measurable.

  10. Multilevel-clamped multilevel converters (MLC2)

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Bellar, Maria Dias; Muñoz-Aguliar, Raúl Santiago

    2012-01-01

    clamping scheme is the ML clamping cell, which is composed of a pair of dc sources associated with one single-pole/triple-throw type of switch arrangement. The number of series-connected ML-clamping cells will set the number of levels of the synthesized waveform. By depending on the MCU arrangements......, different converter configurations can be derived, namely, the common clamping and the modular types. Both approaches can be accomplished by employing classical three-level neutral-point-clamped (NPC) technology. Thus, the overall structure of the resultant converter is kept simple, wherein the number...

  11. Nonlinear beam mechanics

    NARCIS (Netherlands)

    Westra, H.J.R.

    2012-01-01

    In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single and doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like

  12. Full-Duplex Digital Communication on a Single Laser Beam

    Science.gov (United States)

    Hazzard, D. A.; MacCannell, J. A.; Lee, G.; Selves, E. R.; Moore, D.; Payne, J. A.; Garrett, C. D.; Dahlstrom, N.; Shay, T. M.

    2006-01-01

    A proposed free-space optical communication system would operate in a full-duplex mode, using a single constant-power laser beam for transmission and reception of binary signals at both ends of the free-space optical path. The system was conceived for two-way data communication between a ground station and a spacecraft in a low orbit around the Earth. It has been estimated that in this application, a data rate of 10 kb/s could be achieved at a ground-station-to-spacecraft distance of 320 km, using a laser power of only 100 mW. The basic system concept is also applicable to terrestrial free-space optical communications. The system (see figure) would include a diode laser at one end of the link (originally, the ground station) and a liquid-crystal- based retroreflecting modulator at the other end of the link (originally, the spacecraft). At the laser end, the beam to be transmitted would be made to pass through a quarter-wave plate, which would convert its linear polarization to right circular polarization. For transmission of data from the laser end to the retroreflector end, the laser beam would be modulated with subcarrier phase-shift keying (SC-PSK). The transmitted beam would then pass through an aperture- sharing element (ASE) - basically, a mirror with a hole in it, used to separate the paths of the transmitted and received light beams. The transmitted beam would continue outward through a telescope (which, in the original application, would be equipped with a spacecraft-tracking system) that would launch the transmitted beam along the free-space optical path to the retroreflector end.

  13. Clamping characteristics study on different types of clamping unit

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zhiwei; Liu, Haichao; Xie, Pengcheng [College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing China 100029 (China); Yang, Weimin [College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing China 100029 (China); State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing China 100029 (China)

    2015-05-22

    Plastic products are becoming more and more widely used in aerospace, IT, digital electronics and many other fields. With the development of technology, the requirement of product precision is getting higher and higher. However, type and working performance of clamping unit play a decisive role in product precision. Clamping characteristics of different types of clamping unit are discussed in this article, which use finite element numerical analysis method through the software ABAQUS to study the clamping uniformity, and detect the clamping force repeatability precision. The result shows that compared with toggled three-platen clamping unit, clamping characteristics of internal circulation two-platen clamping unit are better, for instance, its mold cavity deformation and force that bars and mold parting surface suffered are more uniform, and its clamping uniformity and repeatability precision is also better.

  14. White beam synchrotron fractography of molybdenum and niobium single crystals

    International Nuclear Information System (INIS)

    Bilello, J.C.; Hmelo, A.B.

    1983-01-01

    It has been demonstrated that a White Beam Synchrotron reflection technique can be used to characterize the fracture surface of Mo and Nb single crystals. This technique when used in conjunction with Berg-Barrett (or in the future monochromatic synchrotron topography) gives detailed information which correlates the internal defect structure to the cleavage surface morphology. In particular, synchrotron fractography has revealed the full extent of the plastic zone associated with a precursor crack, has clearly identified the nature of the initial crack where more than one precursor could have existed, and give detailed information on the extent of twinning and microtwinning. In comparison with other fractography methods for such semi-brittle metals the White Beam Synchrotron method not only achieves rapid data collection, but also provides internal defect structure correlation non-destructively. (author)

  15. Note on beam--beam tune shift in single ring multi bunch mode

    International Nuclear Information System (INIS)

    Month, M.

    1978-01-01

    If many identical counter-rotating bunches of protons and antiprotons are stored in a single ring, they will have identical orbits. The question is: Is this total tune shift relevant to the problem of beam stability. The answer is: not in general. The nonlinear force is described by its ''strength'', Δν/sub I/, for each bunch interaction individually. It is not at all clear that the sum of the individual Δν/sub I/ is the significant quantity

  16. Electron-beam-induced fracture of Kevlar single fibers

    International Nuclear Information System (INIS)

    Dickinson, J.T.; Jensen, L.C.; Klakken, M.L.

    1986-01-01

    We examine the unique situation involving the exposure of polymers to both electron bombardment and mechanical stress. Under certain conditions, crack formation, crack growth, and fracture can occur due to this combination of stimuli. These studies relate to the performance of a number of materials under hostile environments such as space, plasma, and propulsion systems. In this paper we present our initial measurements on the response of single Kevlar fibers loaded in tension to bombardment by 3-keV electrons. We present evidence that the resulting electron-beam-induced fracture is due to bond breaking

  17. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Directory of Open Access Journals (Sweden)

    McKinlay J.

    2012-10-01

    Full Text Available To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal and 75 um (vertical.

  18. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Science.gov (United States)

    Tan, Y.-R. E.; Wang, D.; Van Garderen, E.; McKinlay, J.

    2012-10-01

    To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM) has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR) of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre) of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal) and 75 um (vertical).

  19. The Single Pass RF Driver: Final beam compression

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Robert, E-mail: rjburke@fusionpowercorporation.com

    2014-01-01

    The Single Pass RF Driver (SPRFD) compacts the beam from the linac without storage rings by manipulations that take advantage of the multiplicity of isotopes (16), the preserved µbunch structure, and increased total linac current. Magnetic switches on a first set of delay lines rearrange the internal structure of the various isotopic beams. A second set of delay lines sets the relative timing of the 16 isotopic beam sections so they will telescope at the pellet, in one of multiple fusion chambers, e.g. 10. Shortening each isotopic beam section uses preservation of the µbunch structure up to the final ∼2 km drift before final focus. Just before the final drift, differential acceleration of the µbunches in each isotopic beam section (128 total) launches an axial collapse, referred to as the “Slick”. The µbunches interpenetrate as their centers of mass move toward each other and individual µbunches lengthen due to their momentum spread. In longitudinal phase space they slide over one another as they lengthen in time and slim down in instantaneous energy spread. The permissible amount of µbunch lengthening is set by the design pulse shape at the pellet, which varies for different groups of isotopes. In narrow bands of ranges according to the role for each isotope group in the pellet, the ranges extend from 1 to 10 g/cm{sup 2} to drive the cylinder barrel and thin hemispherical end caps, to heat the ∼0.5 g/cm{sup 2}ρR fast ignition zone, and to improve the quasi-sphericity of the compression of the fast ignition zones at the pellet's ends. Because the µbunch–µbunch momentum differences are correlated, time-ramped beamline transport elements close after the differential accelerator are used to correct the associated shifts of focal point. Beam neutralization is needed after the differential acceleration until adjacent bunches begin to overlap. Concurrent collapse of each isotope and telescoping of the 16 isotopes cause the current in each beamline

  20. The Single Pass RF Driver: Final beam compression

    International Nuclear Information System (INIS)

    Burke, Robert

    2014-01-01

    The Single Pass RF Driver (SPRFD) compacts the beam from the linac without storage rings by manipulations that take advantage of the multiplicity of isotopes (16), the preserved µbunch structure, and increased total linac current. Magnetic switches on a first set of delay lines rearrange the internal structure of the various isotopic beams. A second set of delay lines sets the relative timing of the 16 isotopic beam sections so they will telescope at the pellet, in one of multiple fusion chambers, e.g. 10. Shortening each isotopic beam section uses preservation of the µbunch structure up to the final ∼2 km drift before final focus. Just before the final drift, differential acceleration of the µbunches in each isotopic beam section (128 total) launches an axial collapse, referred to as the “Slick”. The µbunches interpenetrate as their centers of mass move toward each other and individual µbunches lengthen due to their momentum spread. In longitudinal phase space they slide over one another as they lengthen in time and slim down in instantaneous energy spread. The permissible amount of µbunch lengthening is set by the design pulse shape at the pellet, which varies for different groups of isotopes. In narrow bands of ranges according to the role for each isotope group in the pellet, the ranges extend from 1 to 10 g/cm 2 to drive the cylinder barrel and thin hemispherical end caps, to heat the ∼0.5 g/cm 2 ρR fast ignition zone, and to improve the quasi-sphericity of the compression of the fast ignition zones at the pellet's ends. Because the µbunch–µbunch momentum differences are correlated, time-ramped beamline transport elements close after the differential accelerator are used to correct the associated shifts of focal point. Beam neutralization is needed after the differential acceleration until adjacent bunches begin to overlap. Concurrent collapse of each isotope and telescoping of the 16 isotopes cause the current in each beamline to rise

  1. Trapezoidal diffraction grating beam splitters in single crystal diamond

    Science.gov (United States)

    Kiss, Marcell; Graziosi, Teodoro; Quack, Niels

    2018-02-01

    Single Crystal Diamond has been recognized as a prime material for optical components in high power applications due to low absorption and high thermal conductivity. However, diamond microstructuring remains challenging. Here, we report on the fabrication and characterization of optical diffraction gratings exhibiting a symmetric trapezoidal profile etched into a single crystal diamond substrate. The optimized grating geometry diffracts the transmitted optical power into precisely defined proportions, performing as an effective beam splitter. We fabricate our gratings in commercially available single crystal CVD diamond plates (2.6mm x 2.6mm x 0.3mm). Using a sputter deposited hard mask and patterning by contact lithography, the diamond is etched in an inductively coupled oxygen plasma with zero platen power. The etch process effectively reveals the characteristic {111} diamond crystal planes, creating a precisely defined angled (54.7°) profile. SEM and AFM measurements of the fabricated gratings evidence the trapezoidal shape with a pitch of 3.82μm, depth of 170 nm and duty cycle of 35.5%. Optical characterization is performed in transmission using a 650nm laser source perpendicular to the sample. The recorded transmitted optical power as function of detector rotation angle shows a distribution of 21.1% in the 0th order and 23.6% in each +/-1st order (16.1% reflected, 16.6% in higher orders). To our knowledge, this is the first demonstration of diffraction gratings with trapezoidal profile in single crystal diamond. The fabrication process will enable beam splitter gratings of custom defined optical power distribution profiles, while antireflection coatings can increase the efficiency.

  2. DC proton beam measurements in a single-solenoid low-energy beam transport system

    International Nuclear Information System (INIS)

    Stevens, R.R. Jr.; Schafstall, P.; Schneider, J.D.; Sherman, J.; Zaugg, T.; Taylor, T.

    1994-01-01

    High current, CW proton accelerators are being considered for a number of applications including disposition of nuclear wastes, reduction of fissionable nuclear material inventories, safe production of critical nuclear materials, and energy production. All these applications require the development of high current, reliable, hydrogen ion injectors. In 1986, a program using CW RFQ technology was undertaken at CRL in collaboration with LANL and was continued there until 1993. During this time, an accelerator was built which produced 600 keV, 75 mA and 1,250 keV, 55 mA CW proton beams. The present program at Los Alamos using this accelerator is aimed at continuing the CRL work to demonstrate long-term reliability. In the present work, the authors are seeking to determine the optimal match to and the current limit of the 1,250-keV RFQ. This paper discusses the characterization of the 50 keV beams at the exit of the single-solenoid LEBT and presents both the experimental measurements and the beam simulations done to model this system

  3. Single bunch beam breakup in linacs and BNS damping

    International Nuclear Information System (INIS)

    Toyomasu, Takanori

    1991-12-01

    We study a single-bunch beam breakup (BBU) problem by a macro-particle model. We consider both the BBU solution and the Landau damping solution which includes the Balakin-Novokhatsky-Smirnov (BNS) damping. In the BBU solution, we get an analytic solution which includes both the Chao-Richter-Yao solution and the two-particle model solution and which agrees well with simulation. The solution can also be used in a multi-bunch case. In the Landau damping solution, we can be see the mechanism of Landau damping formally and can get some insights into BNS damping. We confirm that a two-particle model criterion for BNS damping is a good one. We expect that the two-particle model criterion is represented by the first order interaction in Landau damping solution of a macro-particle model. (author)

  4. Ion beam synthesis of buried single crystal erbium silicide

    International Nuclear Information System (INIS)

    Golanski, A.; Feenstra, R.; Galloway, M.D.; Park, J.L.; Pennycook, S.J.; Harmon, H.E.; White, C.W.

    1990-01-01

    High doses (10 16 --10 17 /cm 2 ) of 170 keV Er + were implanted into single-crystal left-angle 111 right-angle Si at implantation temperatures between 350 degree C and 520 degree C. Annealing at 800 degree C in vacuum following the implant, the growth and coalescence of ErSi 2 precipitates leads to a buried single crystalline ErSi 2 layer. This has been studied using Rutherford backscattering/channeling, X-ray diffraction, cross-sectional TEM and resistance versus temperature measurements. Samples implanted at 520 degree C using an Er dose of 7 x 10 16 /cm 2 and thermally annealed were subsequently used as seeds for the mesoepitaxial growth of the buried layer during a second implantation and annealing process. Growth occurs meso-epitaxially along both interfaces through beam induced, defect mediated mobility of Er atoms. The crystalline quality of the ErSi 2 layer strongly depends on the temperature during the second implantation. 12 refs., 4 figs

  5. Correlating Anatomy and Function with Gene Expression in Individual Neurons by Combining in Vivo Labeling, Patch Clamp, and Single Cell RNA-seq

    Directory of Open Access Journals (Sweden)

    Carsten K. Pfeffer

    2017-11-01

    Full Text Available The classification of neurons into distinct types is an ongoing effort aimed at revealing and understanding the diversity of the components of the nervous system. Recently available methods allow us to determine the gene expression pattern of individual neurons in the mammalian cerebral cortex to generate powerful categorization schemes. For a thorough understanding of neuronal diversity such genetic categorization schemes need to be combined with traditional classification parameters like position, axonal projection or response properties to sensory stimulation. Here we describe a method to link the gene expression of individual neurons with their position, axonal projection, or sensory response properties. Neurons are labeled in vivo based on their anatomical or functional properties and, using patch clamp pipettes, their RNA individually harvested in vitro for RNAseq. We validate the methodology using multiple established molecularly and anatomically distinct cell populations and explore molecular differences between uncharacterized neurons in mouse visual cortex. Gene expression patterns between L5 neurons projecting to frontal or contralateral cortex are distinct while L2 neurons differing in position, projection, or function are molecularly similar. With this method we can determine the genetic expression pattern of functionally and anatomically identified individual neurons.

  6. Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron

    International Nuclear Information System (INIS)

    Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro

    2015-01-01

    The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method

  7. Single photon emission computed tomography by using fan beam collimator

    International Nuclear Information System (INIS)

    Akiyama, Yoshihisa

    1992-01-01

    A multislice fan beam collimator which has parallel collimation along the cephalic-caudul axis of a patient and converging collimation within planes that are perpendicular to that axis was designed for a SPECT system with a rotating scintillation camera, and it was constructed by the lead casting method which was developed in recent years. A reconstruction algorithm for fan beam SPECT was formed originally by combining the reconstruction algorithm of the parallel beam SPECT with that of the fan beam X-ray CT. The algorithm for fan beam SPECT was confirmed by means of computer simulation and a head phantom filled with diluted radionuclide. Not only 99m Tc but also 123 I was used as a radionuclide. A SPECT image with the fan beam collimator was compared with that of a parallel hole, low energy, high resolution collimator which was routinely used for clinical and research SPECT studies. Both system resolution and sensitivity of the fan beam collimator were ∼20% better than those of the parallel hole collimator. Comparing SPECT images obtained from fan beam collimator with those of parallel hole collimator, the SPECT images using fan beam collimator had far better resolution. A fan beam collimator is a useful implement for the SPECT study. (author)

  8. A high resolution, single bunch, beam profile monitor

    International Nuclear Information System (INIS)

    Norem, J.

    1992-01-01

    We developed a beam monitoring system which could be used to measure beam profile, size and stability at the final forms of a beamline or collider. The system uses nonimaging bremsstrahlung optics. The immediate use for this system would be examining the final focus spot at the SLAC/FFTR

  9. A high resolution, single bunch, beam profile monitor

    International Nuclear Information System (INIS)

    Norem, J.

    1992-01-01

    Efficient linear colliders require very small beam spots to produce high luminosities with reasonable input power, which limits the number of electrons which can be accelerated to high energies. The small beams, in turn, require high precision and stability in all accelerator components. Producing, monitoring and maintaining beams of the required quality has been, and will continue to be, difficult. A beam monitoring system which could be used to measure beam profile, size and stability at the final focus of a beamline or collider has been developed and is described here. The system uses nonimaging bremsstrahlung optics. The immediate use for this system would be examining the final focus spot at the SLAC/FFTB. The primary alternatives to this technique are those proposed by P. Chen / J. Buon, which analyses the energy and angular distributions of ion recoils to determine the aspect ratio of the electron bunch, and a method proposed by Shintake, which measures intensity variation of compton backscattered photons as the beam is moved across a pattern of standing waves produced by a laser

  10. Vibrations and stability of complex beam systems

    CERN Document Server

    Stojanović, Vladimir

    2015-01-01

     This book reports on solved problems concerning vibrations and stability of complex beam systems. The complexity of a system is considered from two points of view: the complexity originating from the nature of the structure, in the case of two or more elastically connected beams; and the complexity derived from the dynamic behavior of the system, in the case of a damaged single beam, resulting from the harm done to its simple structure. Furthermore, the book describes the analytical derivation of equations of two or more elastically connected beams, using four different theories (Euler, Rayleigh, Timoshenko and Reddy-Bickford). It also reports on a new, improved p-version of the finite element method for geometrically nonlinear vibrations. The new method provides more accurate approximations of solutions, while also allowing us to analyze geometrically nonlinear vibrations. The book describes the appearance of longitudinal vibrations of damaged clamped-clamped beams as a result of discontinuity (damage). It...

  11. Three-dimensional SPECT [single photon emission computed tomography] reconstruction of combined cone beam and parallel beam data

    International Nuclear Information System (INIS)

    Jaszczak, R.J.; Jianying Li; Huili Wang; Coleman, R.E.

    1992-01-01

    Single photon emission computed tomography (SPECT) using cone beam (CB) collimation exhibits increased sensitivity compared with acquisition geometries using parallel (P) hole collimation. However, CB collimation has a smaller field-of-view which may result in truncated projections and image artifacts. A primary objective of this work is to investigate maximum likelihood-expectation maximization (ML-EM) methods to reconstruct simultaneously acquired parallel and cone beam (P and CB) SPECT data. Simultaneous P and CB acquisition can be performed with commercially available triple camera systems by using two cone-beam collimators and a single parallel-hole collimator. The loss in overall sensitivity (relative to the use of three CB collimators) is about 15 to 20%. The authors have developed three methods to combine P and CB data using modified ML-EM algorithms. (author)

  12. Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

    KAUST Repository

    Ruzziconi, Laura; Lenci, Stefano; Younis, Mohammad I.

    2016-01-01

    This study deals with the nonlinear dynamics arising in an atomic force microscope cantilever beam. After analyzing the static behavior, a single degree of freedom Galerkin reduced order model is introduced, which describes the overall scenario

  13. Binary codes storage and data encryption in substrates with single proton beam writing technology

    International Nuclear Information System (INIS)

    Zhang Jun; Zhan Furu; Hu Zhiwen; Chen Lianyun; Yu Zengliang

    2006-01-01

    It has been demonstrated that characters can be written by proton beams in various materials. In contributing to the rapid development of proton beam writing technology, we introduce a new method for binary code storage and data encryption by writing binary codes of characters (BCC) in substrates with single proton beam writing technology. In this study, two kinds of BCC (ASCII BCC and long bit encrypted BCC) were written in CR-39 by a 2.6 MeV single proton beam. Our results show that in comparison to directly writing character shapes, writing ASCII BCC turned out to be about six times faster and required about one fourth the area in substrates. The approach of writing long bit encrypted BCC by single proton beams supports preserving confidential information in substrates. Additionally, binary codes fabricated by MeV single proton beams in substrates are more robust than those formed by lasers, since MeV single proton beams can make much deeper pits in the substrates

  14. Integrated single- and two-photon light sheet microscopy using accelerating beams

    DEFF Research Database (Denmark)

    Piksarv, Peeter; Marti, Dominik; Le, Tuan

    2017-01-01

    We demonstrate the first light sheet microscope using propagation invariant, accelerating Airy beams that operates both in single- and two-photon modes. The use of the Airy beam permits us to develop an ultra compact, high resolution light sheet system without beam scanning. In two-photon mode......, an increase in the field of view over the use of a standard Gaussian beam by a factor of six is demonstrated. This implementation for light sheet microscopy opens up new possibilities across a wide range of biomedical applications, especially for the study of neuronal processes....

  15. A single-beam deuteron compact accelerator for neutron generation

    International Nuclear Information System (INIS)

    Araujo, Wagner Leite; Campos, Tarcisio Passos Ribeiro de

    2011-01-01

    Portable neutron generators are devices composed by small size accelerators that produce neutrons through fusion between hydrogen isotopes. These reactions are characterized by appreciable cross section at energies at the tens of keV, which enables device portability. The project baselines follow the same physical and engineering principles of any other particle accelerators. The generator consists of a gas reservoir, apparatus for ion production, few electrodes to accelerate and focus the ion beam, and a metal hydride target where fusion reactions occur. Neutron generator applications include geophysical measurements, indus- trial process control, environmental, research, nation's security and mechanical structure analysis.This article presents a design of a compact accelerator for d-d neutron generators, describing the physical theory applied to the deuteron extraction system, and simulating the ion beam transport in the accelerator. (author)

  16. Formation of a single-bunch beam in the booster synchrotron at SPring-8

    CERN Document Server

    Suzuki, H; Ego, H; Hara, M; Hosoda, N; Kawashima, Y; Ohashi, Y; Ohshima, T; Tani, N; Yabashi, M; Yonehara, H

    2000-01-01

    In order to fill a radio frequency (rf) bucket with an electron beam in the storage ring at SPring-8, an rf knockout system was installed in the booster synchrotron. With this system, the energy of the electron beam injected from the linac was increased from 1 to 8 GeV. The time width of multi-bunch beams from the linac operated at 2856 MHz rf can be selected as 1 or 40 ns. The beam injected from the linac is distributed in rf buckets of the booster synchrotron operated at 508.58 MHz rf. To fill a single rf bucket with a beam, the rf knockout system is operated at a minimum beam energy of 1 GeV. By using the rf knockout system, the electron beam is effectively kept in a single rf bucket. Then the beam is injected into a targeted rf bucket in the storage ring with a precise timing system. The beam intensity of satellite rf buckets in the storage ring was measured with a photon counting method and determined to be 10 sup - sup 6 less than that of the main rf bucket. In this paper, we describe the rf knockout sy...

  17. X-ray beam monitor made by thin-film CVD single-crystal diamond.

    Science.gov (United States)

    Marinelli, Marco; Milani, E; Prestopino, G; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M; Kachkanov, V; Tartoni, N; Benetti, M; Cannatà, D; Di Pietrantonio, F

    2012-11-01

    A novel beam position monitor, operated at zero bias voltage, based on high-quality chemical-vapor-deposition single-crystal Schottky diamond for use under intense synchrotron X-ray beams was fabricated and tested. The total thickness of the diamond thin-film beam monitor is about 60 µm. The diamond beam monitor was inserted in the B16 beamline of the Diamond Light Source synchrotron in Harwell (UK). The device was characterized under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of approximately 2 µm × 3 µm square. Time response, linearity and position sensitivity were investigated. Device response uniformity was measured by a raster scan of the diamond surface with the micro-focused beam. Transmissivity and spectral responsivity versus beam energy were also measured, showing excellent performance of the new thin-film single-crystal diamond beam monitor.

  18. Clamp wins pipe repair prize

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-04-01

    This paper describes the permanent pipeline repair system, developed by Tekmar, which is powered by seawater hydraulics and is easily installed and tested by any workclass remotely operated vehicle (rov). Details are given of the two main components of the system, namely, the diverless high pressure split repair clamp and the rov-operated tool to install it.

  19. Single beam collective effects in FCC-ee due to beam coupling impedance

    CERN Document Server

    Belli, Eleonora; Persichelli, Serena; Zobov, Mikhail

    2016-01-01

    The Future Circular Collider study, hosted by CERN to design post-LHC particle accelerator options in a worldwide context, is focused on proton-proton high-energy and electron-positron high-luminosity frontier machines. This new accelerator complex represents a great challenge under several aspects, which involve R&D on beam dynamics and new technologies. One very critical point in this context is represented by collective effects, generated by the interaction of the beam with self-induced electromagnetic fields, called wake fields, which could produce beam instabilities, thus reducing the machines performance and limiting the maximum stored current. It is therefore very important to be able to predict these effects and to study in detail potential solutions to counteract them. In this paper the resistive wall and some other important geometrical sources of impedance for the FCC electron-positron accelerator are identified and evaluated, and their impact on the beam dynamics, which in some cases could lea...

  20. Single beam collective effects in FCC-ee due to beam coupling impedance

    CERN Document Server

    Belli, Eleonora

    2016-01-01

    The Future Circular Collider study, hosted by CERN to design post-LHC particle accelerator options in a worldwide context, is focused on proton-proton high-energy and electron-positron high-luminosity frontier machines. This new accelerator complex represents a great challenge under several aspects, which involve R&D on beam dynamics and new technologies. One very critical point in this context is represented by collective effects, generated by the interaction of the beam with self-induced electromagnetic fields, called wake fields, which could produce beam instabilities, thus reducing the machines performance and limiting the maximum stored current. It is therefore very important to be able to predict these effects and to study in detail potential solutions to counteract them. In this paper the resistive wall and some other important geometrical sources of impedance for the FCC electron-positron accelera- tor are identified and evaluated, and their impact on the beam dynamics, which in some cases could l...

  1. Corpuscular Model of Two-Beam Interference and Double-Slit Experiments with Single Photons

    NARCIS (Netherlands)

    Jin, Fengping; Yuan, Shengjun; De Raedt, Hans; Michielsen, Kristel; Miyashita, Seiji

    We introduce an event-based corpuscular simulation model that reproduces the wave mechanical results of single-photon double-slit and two-beam interference experiments and (of a one-to-one copy of an experimental realization) of a single-photon interference experiment with a Fresnel biprism. The

  2. Determination of beam intensity in a single step for IMRT inverse planning

    International Nuclear Information System (INIS)

    Chuang, Keh-Shih; Chen, Tzong-Jer; Kuo, Shan-Chi; Jan, Meei-Ling; Hwang, Ing-Ming; Chen, Sharon; Lin, Ying-Chuan; Wu, Jay

    2003-01-01

    In intensity modulated radiotherapy (IMRT), targets are treated by multiple beams at different orientations each with spatially-modulated beam intensities. This approach spreads the normal tissue dose to a greater volume and produces a higher dose conformation to the target. In general, inverse planning is used for IMRT treatment planning. The inverse planning requires iterative calculation of dose distribution in order to optimize the intensity profile for each beam and is very computation intensive. In this paper, we propose a single-step method utilizing a figure of merit (FoM) to estimate the beam intensities for IMRT treatment planning. The FoM of a ray is defined as the ratio between the delivered tumour dose and normal tissue dose and is a good index for the dose efficacy of the ray. To maximize the beam utility, it is natural to irradiate the tumour with intensity of each ray proportional to the value of the FoM. The nonuniform beam intensity profiles are then fixed and the weights of the beam are determined iteratively in order to yield a uniform tumour dose. In this study, beams are employed at equispaced angles around the patient. Each beam with its field size that just covers the tumour is divided into a fixed number of beamlets. The FoM is calculated for each beamlet and this value is assigned to be the beam intensity. Various weighting factors are incorporated in the FoM computation to accommodate different clinical considerations. Two clinical datasets are used to test the feasibility of the algorithm. The resultant dose-volume histograms of this method are presented and compared to that of conformal therapy. Preliminary results indicate that this method reduces the critical organ doses at a small expense of uniformity in tumour dose distribution. This method estimates the beam intensity in one single step and the computation time is extremely fast and can be finished in less than one minute using a regular PC

  3. Single beam write and/or replay of spatial heterodyne holograms

    Science.gov (United States)

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  4. Molecular beam epitaxy of single crystal colossal magnetoresistive material

    International Nuclear Information System (INIS)

    Eckstein, J.N.; Bozovic, I.; Rzchowski, M.; O'Donnell, J.; Hinaus, B.; Onellion, M.

    1996-01-01

    The authors have grown films of (LaSr)MnO 3 (LSMO) and (LaCa)MnO 3 (LCMO) using atomic layer-by-layer molecular beam epitaxy (ALL-MBE). Depending on growth conditions, substrate lattice constant and the exact cation stoichiometry, the films are either pseudomorphic or strain relaxed. The pseudomorphic films show atomically flat surfaces, with a unit cell terrace structure that is a replica of that observed on the slightly vicinal substrates, while the strain relaxed films show bumpy surfaces correlated with a dislocation network. All films show tetragonal structure and exhibit anisotropic magnetoresistance, with a low field response, (1/R)(dR/dH) as large as 5 T -1

  5. Multifrequency Excitation of a Clamped-Clamped Microbeam

    KAUST Repository

    Jaber, Nizar R.

    2016-01-20

    We present analytical and experimental investigation of an electrically actuated clamped-clamped microbeam under a twosource harmonic excitation. The first frequency is swept around the first mode of vibration where the second one is fixed. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency and the amplitude of the excitation force, the frequency bandwidth of the resonator is increased. Theoretically, we solved the eigenvalue problem for different axial forces to find the natural frequencies ratio that match the experimental values. Using Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device where using three symmetric mode shapes provided a good agreement with experimental data. © Copyright 2015 by ASME.

  6. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    2001-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surface has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen Isotopic defined beams from Pd (111) surface in the 40-400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one to the 5% D/(D+H) ratio - and for different incident energies. The beam was directed onto a single-crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to it. (authors)

  7. Scintillation of lead tungstate crystal studied with single-electron beam from KUFEL

    Energy Technology Data Exchange (ETDEWEB)

    Rizwan, Mohamad, E-mail: rizwan@nucl.kyushu-u.ac.jp; Uozumi, Yusuke; Matsuo, Kazuki [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka (Japan); Ohgaki, Hideaki; Kii, Toshiteru; Zen, Heishun [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto (Japan); Tsamalaidze, Zviadi; Evtoukhovitch, Petr; Valentin, Samoilov [Joint Institute for Nuclear Research, JINR, Joliot-Curie Str.6, Dubna (Russian Federation)

    2015-04-29

    Lead tungstate (PWO) crystal has a very fast response, high atomic density and high radiation hardness. Therefore, they are suitable to be used for high-energy nuclear data measurements under high-background circumstances. Although a good electron-ion separation with a pulse shape analysis technique is essential, scintillation pulse shapes have not been observed with electron beams of a wide energy range. A single-electron beam technique has been developed at Kyoto University Free Electron Laser (KUFEL), and electron beams of 4-38 MeV are available. During the experiments, single electron beams bombarded a PWO crystal. By using oscilloscope we observed scintillation pulses of a PWO crystal coupled with a photomultiplier tube. Measured spectra were compared with the simulation code of EGS5 to analyze scattering effects. As the result, the pulse amplitudes show good linearity and the pulse shapes are almost constant in the observed energy range.

  8. MeV single-ion beam irradiation of mammalian cells using the Surrey vertical nanobeam, compared with broad proton beam and X-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Jeynes, J.C.G.; Merchant, M.J.; Kirkby, K.; Kirkby, N. [Surrey Ion Beam Center, Faculty of Engineering and Physical Science, University of Surrey, Guildford Surrey, GU2 7XH (United Kingdom); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: •Recently completed nanobeam at the Surrey Ion Beam Centre was used. •3.8-MeV single and broad proton beams irradiated Chinese hamster cells. •Cell survival curves were measured and compared with 300-kV X-ray irradiation. •Single ion irradiation had a lower survival part at ultra-low dose. •It implies hypersensitivity, bystander effect and cell cycle phase of cell death. -- Abstract: As a part of a systematic study on mechanisms involved in physical cancer therapies, this work investigated response of mammalian cells to ultra-low-dose ion beam irradiation. The ion beam irradiation was performed using the recently completed nanobeam facility at the Surrey Ion Beam Centre. A scanning focused vertical ion nano-beam was applied to irradiate Chinese hamster V79 cells. The V79 cells were irradiated in two different beam modes, namely, focused single ion beam and defocused scanning broad ion beam of 3.8-MeV protons. The single ion beam was capable of irradiating a single cell with a precisely controlled number of the ions to extremely low doses. After irradiation and cell incubation, the number of surviving colonies as a function of the number of the irradiating ions was measured for the cell survival fraction curve. A lower survival for the single ion beam irradiation than that of the broad beam case implied the hypersensitivity and bystander effect. The ion-beam-induced cell survival curves were compared with that from 300-kV X-ray irradiation. Theoretical studies indicated that the cell death in single ion irradiation mainly occurred in the cell cycle phases of cell division and intervals between the cell division and the DNA replication. The success in the experiment demonstrated the Surrey vertical nanobeam successfully completed.

  9. Report on first masing and single mode locking in a prebunched beam FEM oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, M.; Eichenbaum, A.; Kleinman, H. [Tel-Aviv Univ., Ramat-Aviv (Israel)] [and others

    1995-12-31

    Radiation characteristics of a table-top free electron maser (FEM) are described in this paper. The FEM employs a prebunched electron beam and is operated as an oscillator in the low-gain collective (Raman) regime. Using electron beam prebunching single mode locking at any one of the possible oscillation modes was obtained. The electron beam is prebunched by a microwave tube section before it is injected into the wiggler. By tuning the electron beam bunching frequency, the FEM oscillation frequency can be locked to any eigen frequency of the resonant waveguide cavity which is within the frequency band of net gain of the FEM. The oscillation build up process is sped up, when the FEM operates with a prebunched electron beam, and the build-up time of radiation is shortened significantly. First measurements of masing with and without prebunching and characterization of the emitted radiation are reported.

  10. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    Science.gov (United States)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-07-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers.

  11. Computer generation of cobalt-60 single beam dose distribution using an analytical beam model

    International Nuclear Information System (INIS)

    Jayaraman, S.

    1981-01-01

    A beam dose calculation model based on evaluation of tissue air ratios (TAR) and scatter air ratios (SAR) for cobalt-60 beams of rectangular cross section has been developed. Off-central axis fall-off of primary radiation intensity is derived by an empirical formulation involving an arctangent function with the slope of the geometrical penumbra acting as an essential constant. Central axis TAR and SAR values are assessed by semi-empirical polynomial expressions employing the two sides of the rectangular field as the bariables. The model utilises a minimum number of parametric constants and is useful for computer generation of isodose curves. The model is capable of accounting for situations where wedge filters or split field shielding blocks, are encountered. Further it could be widely applied with minor modifications to several makes of the currently available cobalt-60 units. The paper explains the model and shows examples of the results obtained in comparison with the corresponding experimentally determined dose distributions. (orig.) [de

  12. Composite Beam Cross-Section Analysis by a Single High-Order Element Layer

    DEFF Research Database (Denmark)

    Couturier, Philippe; Krenk, Steen

    2015-01-01

    An analysis procedure of general cross-section properties is presented. The formulation is based on the stress-strain states in the classic six equilibrium modes of a beam by considering a finite thickness slice modelled by a single layer of 3D finite elements. The theory is illustrated by applic......An analysis procedure of general cross-section properties is presented. The formulation is based on the stress-strain states in the classic six equilibrium modes of a beam by considering a finite thickness slice modelled by a single layer of 3D finite elements. The theory is illustrated...

  13. Synchronous timing of multi-energy fast beam extraction during a single AGS cycle

    International Nuclear Information System (INIS)

    Gabusi, J.; Naase, S.

    1985-01-01

    Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating rf waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a ''hole'', which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous rf/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the ''hole'' in any desired location within the second extraction. The rf/12 signal is used also to synchronize experimenters triggers

  14. Single side damage simulations and detection in beam-like structures

    International Nuclear Information System (INIS)

    Zhou, Yun-Lai; Perera, R; Wahab, M Abdel; Maia, N; Sampaio, R; Figueiredo, E

    2015-01-01

    Beam-like structures are the most common components in real engineering, while single side damage is often encountered. In this study, a numerical analysis of single side damage in a free-free beam is analysed with three different finite element models; namely solid, shell and beam models for demonstrating their performance in simulating real structures. Similar to experiment, damage is introduced into one side of the beam, and natural frequencies are extracted from the simulations and compared with experimental and analytical results. Mode shapes are also analysed with modal assurance criterion. The results from simulations reveal a good performance of the three models in extracting natural frequencies, and solid model performs better than shell while shell model performs better than beam model under intact state. For damaged states, the natural frequencies captured from solid model show more sensitivity to damage severity than shell model and shell model performs similar to the beam model in distinguishing damage. The main contribution of this paper is to perform a comparison between three finite element models and experimental data as well as analytical solutions. The finite element results show a relatively well performance. (paper)

  15. Three-dimensional orientation-unlimited polarization encryption by a single optically configured vectorial beam.

    Science.gov (United States)

    Li, Xiangping; Lan, Tzu-Hsiang; Tien, Chung-Hao; Gu, Min

    2012-01-01

    The interplay between light polarization and matter is the basis of many fundamental physical processes and applications. However, the electromagnetic wave nature of light in free space sets a fundamental limit on the three-dimensional polarization orientation of a light beam. Although a high numerical aperture objective can be used to bend the wavefront of a radially polarized beam to generate the longitudinal polarization state in the focal volume, the arbitrary three-dimensional polarization orientation of a beam has not been achieved yet. Here we present a novel technique for generating arbitrary three-dimensional polarization orientation by a single optically configured vectorial beam. As a consequence, by applying this technique to gold nanorods, orientation-unlimited polarization encryption with ultra-security is demonstrated. These results represent a new landmark of the orientation-unlimited three-dimensional polarization control of the light-matter interaction.

  16. Is early cord clamping, delayed cord clamping or cord milking best?

    Science.gov (United States)

    Vatansever, Binay; Demirel, Gamze; Ciler Eren, Elif; Erel, Ozcan; Neselioglu, Salim; Karavar, Hande Nur; Gundogdu, Semra; Ulfer, Gozde; Bahadir, Selcen; Tastekin, Ayhan

    2018-04-01

    To compare the antioxidant status of three cord clamping procedures (early clamping, delayed clamping and milking) by analyzing the thiol-disulfide balance. This randomized controlled study enrolled 189 term infants who were divided into three groups according to the cord clamping procedure: early clamping, delayed clamping and milking. Blood samples were collected from the umbilical arteries immediately after clamping, and the thiol/disulfide homeostasis was analyzed. The native and total thiol levels were significantly (p total thiol ratio was significantly (p = .026) lower in the delayed cord clamping and milking groups compared with the early clamping groups. Early cord clamping causes the production of more disulfide bonds and lower thiol levels, indicating that oxidation reactions are increased in the early cord clamping procedure compared with the delayed cord clamping and milking procedures. The oxidant capacity is greater with early cord clamping than with delayed clamping or cord milking. Delayed cord clamping or milking are beneficial in neonatal care, and we suggest that they be performed routinely in all deliveries.

  17. Single-shot beam size measurements using visible-light interferometry at CESR

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.T., E-mail: sw565@cornell.edu [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Holtzapple, R. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Rubin, D.L. [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, NY 14853 (United States)

    2017-03-01

    A new primary mirror for a visible-light beam size monitor (vBSM) was designed and installed in the Cornell Electron-Positron Storage Ring (CESR). The vertical angular acceptance of the mirror was doubled to allow double-slit interferometry with large slit separation (>12 mm). In addition, the diffraction associated with the first generation mirror has been eliminated. The resolution of the vertical beam size measurements has been dramatically improved but is ultimately limited by the beam motion. Two fast-response detectors, a Photomultiplier Tube (PMT) array and a gated camera, were employed to study the beam motion. The advantages and limitations of both devices are discussed in this paper. The gated camera was also used to measure single-shot beam width and motion of each bunch in a multi-bunch train. We measured significantly more horizontal motion of electron as compared to positron bunch trains in otherwise identical machine condition. This difference may be a signature for the difference between electron cloud build-up for positron bunch trains versus ions effects characteristic of electron bunch trains. - Highlights: • A new extraction mirror for synchrotron radiation was designed and installed in CESR. • The sensitivity of interferometer was increased and the diffraction effect was eliminated. • Two fast-response detectors were employed to study the effect of beam motion. • First time single-shot bunch-by-bunch horizontal beam size measurements using interferometry was observed from gated camera. • The difference in single bunch horizontal dynamics was observed between a positron and an electron train.

  18. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    1999-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surfaces has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen isotopic defined beams from Pd (111) surfaces in the 40 - 400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one until 5% D/(D + H) and different incident energies and directed onto a single - crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to them. (authors)

  19. Single-Axis Three-Beam Amplitude Monopulse Antenna-Signal Processing Issues

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-05-01

    Typically, when three or more antenna beams along a single axis are required, the answer has been multiple antenna phase-centers, essentially a phase-monopulse system. Such systems and their design parameters are well-reported in the literature. Less appreciated is that three or more antenna beams can also be generated in an amplitude-monopulse fashion. Consequently, design guidelines and performance analysis of such antennas is somewhat under-reported in the literature. We provide discussion herein of three beams arrayed in a single axis with an amplitude-monopulse configuration. Acknowledgements The preparation of this report is the result of an unfunded research and development activity. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administ ration under contract DE-AC04-94AL85000.

  20. Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

    DEFF Research Database (Denmark)

    Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.

    1965-01-01

    Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...

  1. Stacking fault energy measurements in WSe2 single crystals using weak-beam techniques

    International Nuclear Information System (INIS)

    Agarwal, M.K.; Patel, J.V.; Patel, N.G.

    1981-01-01

    The weak-beam method of electron microscopy is used to observe threefold dislocations in WSe 2 single crystals grown by direct vapour transport method. The widths of the three fold ribbons are used to determine the stacking fault energy in these crystals. Variation of the width of the ribbons with temperature are also studied and discussed. (author)

  2. Production of multi-, oligo- and single-pore membranes using a continuous ion beam

    Czech Academy of Sciences Publication Activity Database

    Apel, P. Yu.; Ivanov, O.; Lizunov, N. E.; Mamonova, T. I.; Nechaev, A. N.; Olejniczak, K.; Vacík, Jiří; Dmitriev, S. N.

    2015-01-01

    Roč. 365, DEC (2015), s. 641-645 ISSN 0168-583X R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : ion beam * irradiation * ion track * etching * single nanopore Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.389, year: 2015

  3. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    International Nuclear Information System (INIS)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-01-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers. - Highlights: • Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. • Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. • However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. • Optical tweezers can trap, move and positioned micron size particles with subnanometer accuracy in three dimensions. • One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. • Acoustical tweezers overcome this limitation since the force scales as the field intensity divided by its propagation speed. • However, the feasibility of single beam acoustical tweezers was demonstrated only recently. • We propose a review of the strong similarities but also the specificities of acoustical

  4. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  5. Application of active electrode compensation to perform continuous voltage-clamp recordings with sharp microelectrodes.

    Science.gov (United States)

    Gómez-González, J F; Destexhe, A; Bal, T

    2014-10-01

    Electrophysiological recordings of single neurons in brain tissues are very common in neuroscience. Glass microelectrodes filled with an electrolyte are used to impale the cell membrane in order to record the membrane potential or to inject current. Their high resistance induces a high voltage drop when passing current and it is essential to correct the voltage measurements. In particular, for voltage clamping, the traditional alternatives are two-electrode voltage-clamp technique or discontinuous single electrode voltage-clamp (dSEVC). Nevertheless, it is generally difficult to impale two electrodes in a same neuron and the switching frequency is limited to low frequencies in the case of dSEVC. We present a novel fully computer-implemented alternative to perform continuous voltage-clamp recordings with a single sharp-electrode. To reach such voltage-clamp recordings, we combine an active electrode compensation algorithm (AEC) with a digital controller (AECVC). We applied two types of control-systems: a linear controller (proportional plus integrative controller) and a model-based controller (optimal control). We compared the performance of the two methods to dSEVC using a dynamic model cell and experiments in brain slices. The AECVC method provides an entirely digital method to perform continuous recording and smooth switching between voltage-clamp, current clamp or dynamic-clamp configurations without introducing artifacts.

  6. Cone beam tomography of the heart using single-photon emission-computed tomography

    International Nuclear Information System (INIS)

    Gullberg, G.T.; Christian, P.E.; Zeng, G.L.; Datz, F.L.; Morgan, H.T.

    1991-01-01

    The authors evaluated cone beam single-photon emission-computed tomography (SPECT) of the heart. A new cone beam reconstruction algorithm was used to reconstruct data collected from short scan acquisitions (of slightly more than 180 degrees) of a detector anteriorally traversing a noncircular orbit. The less than 360 degrees acquisition was used to minimize the attenuation artifacts that result from reconstructing posterior projections of 201T1 emissions from the heart. The algorithm includes a new method for reconstructing truncated projections of background tissue activity that eliminates reconstruction ring artifacts. Phantom and patient results are presented which compare a high-resolution cone beam collimator (50-cm focal length; 6.0-mm full width at half maximum [FWHM] at 10 cm) to a low-energy general purpose (LEGP) parallel hole collimator (8.2-mm FWHM at 10 cm) which is 1.33 times more sensitive. The cone beam tomographic results are free of reconstruction artifacts and show improved spatial and contrast resolution over that obtained with the LEGP parallel hole collimator. The limited angular sampling restrictions and truncation problems associated with cone beam tomography do not deter from obtaining diagnostic information. However, even though these preliminary results are encouraging, a thorough clinical study is still needed to investigate the specificity and sensitivity of cone beam tomography

  7. Effects of underwater turbulence on laser beam propagation and coupling into single-mode optical fiber.

    Science.gov (United States)

    Hanson, Frank; Lasher, Mark

    2010-06-01

    We characterize and compare the effects of turbulence on underwater laser propagation with theory. Measurements of the coupling efficiency of the focused beam into a single-mode fiber are reported. A simple tip-tilt control system, based on the position of the image centroid in the focal plane, was shown to maintain good coupling efficiency for a beam radius equal to the transverse coherence length, r(0). These results are relevant to high bandwidth communication technology that requires good spatial mode quality.

  8. Dynamic Actuation of Single-Crystal Diamond Nanobeams

    OpenAIRE

    Sohn, Young-Ik; Burek, Michael J.; Kara, Vural; Kearns, Ryan; Lončar, Marko

    2014-01-01

    We show the dielectrophoretic actuation of single-crystal diamond nanomechanical devices. Gradient radio-frequency electromagnetic forces are used to achieve actuation of both cantilever and doubly clamped beam structures, with operation frequencies ranging from a few MHz to ~50MHz. Frequency tuning and parametric actuation are also studied.

  9. Analysis list: Clamp [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Clamp Cell line + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clamp.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clam...p.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clam...p.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Clamp.Cell_line.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cell_line.gml ...

  10. Single-slice rebinning method for helical cone-beam CT

    International Nuclear Information System (INIS)

    Noo, F.; Defrise, M.; Clackdoyle, R.

    1999-01-01

    In this paper, we present reconstruction results from helical cone-beam CT data, obtained using a simple and fast algorithm, which we call the CB-SSRB algorithm. This algorithm combines the single-slice rebinning method of PET imaging with the weighting schemes of spiral CT algorithms. The reconstruction is approximate but can be performed using 2D multislice fan-beam filtered backprojection. The quality of the results is surprisingly good, and far exceeds what one might expect, even when the pitch of the helix is large. In particular, with this algorithm comparable quality is obtained using helical cone-beam data with a normalized pitch of 10 to that obtained using standard spiral CT reconstruction with a normalized pitch of 2. (author)

  11. The tensile effect on crack formation in single crystal silicon irradiated by intense pulsed ion beam

    Science.gov (United States)

    Liang, Guoying; Shen, Jie; Zhang, Jie; Zhong, Haowen; Cui, Xiaojun; Yan, Sha; Zhang, Xiaofu; Yu, Xiao; Le, Xiaoyun

    2017-10-01

    Improving antifatigue performance of silicon substrate is very important for the development of semiconductor industry. The cracking behavior of silicon under intense pulsed ion beam irradiation was studied by numerical simulation in order to understand the mechanism of induced surface peeling observed by experimental means. Using molecular dynamics simulation based on Stillinger Weber potential, tensile effect on crack growth and propagation in single crystal silicon was investigated. Simulation results reveal that stress-strain curves of single crystal silicon at a constant strain rate can be divided into three stages, which are not similar to metal stress-strain curves; different tensile load velocities induce difference of single silicon crack formation speed; the layered stress results in crack formation in single crystal silicon. It is concluded that the crack growth and propagation is more sensitive to strain rate, tensile load velocity, stress distribution in single crystal silicon.

  12. Tensile properties of electron-beam-welded single crystals of molybdenum

    International Nuclear Information System (INIS)

    Hiraoka, Yutaka; Okada, Masatoshi; Irie, Hirosada; Fujii, Tadayuki.

    1987-01-01

    The purpose of this study is to investigate the macro- and microstructures and the tensile properties of electron-beam-welded single crystals of molybdenum. The single-crystal sheets were prepared by means of secondary recrystallization. The welding was carried out by a melt-run technique. The weld metal had the same crystallographic orientation as the base metal, and no grain boundary was observed. However, many large weld pores were formed mostly along the weld bond. The strength and ductility of the welded joints of single crystals were almost the same as those of the base metal (''annealed'' single crystals). It is concluded that the joint efficiency of molybdenum single crystals at room temperature or above was excellent and nearly 100 %. (author)

  13. A feasibility study of in vivo applications of single beam acoustic tweezers

    International Nuclear Information System (INIS)

    Li, Ying; Lee, Changyang; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk

    2014-01-01

    Tools that are capable of manipulating micro-sized objects have been widely used in such fields as physics, chemistry, biology, and medicine. Several devices, including optical tweezers, atomic force microscope, micro-pipette aspirator, and standing surface wave type acoustic tweezers have been studied to satisfy this need. However, none of them has been demonstrated to be suitable for in vivo and clinical studies. Single beam acoustic tweezers (SBAT) is a technology that uses highly focused acoustic beam to trap particles toward the beam focus. Its feasibility was first theoretically and experimentally demonstrated by Lee and Shung several years ago. Since then, much effort has been devoted to improving this technology. At present, the tool is capable of trapping a microparticle as small as 1 μm, as well as a single red blood cell. Although in comparing to other microparticles manipulating technologies, SBAT has advantages of providing stronger trapping force and deeper penetration depth in tissues, and producing less tissue damage, its potential for in vivo applications has yet been explored. It is worth noting that ultrasound has been used as a diagnostic tool for over 50 years and no known major adverse effects have been observed at the diagnostic energy level. This paper reports the results of an initial attempt to assess the feasibility of single beam acoustic tweezers to trap microparticles in vivo inside of a blood vessel. The acoustic intensity of SBAT under the trapping conditions that were utilized was measured. The mechanical index and thermal index at the focus of acoustic beam were found to be 0.48 and 0.044, respectively, which meet the standard of commercial diagnostic ultrasound system.

  14. A feasibility study of in vivo applications of single beam acoustic tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying, E-mail: yli582@usc.edu; Lee, Changyang; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk [NIH Transducer Resource Center and Department of Biomedical Engineering, University of Southern California, Los Angeles, California 90089-1111 (United States)

    2014-10-27

    Tools that are capable of manipulating micro-sized objects have been widely used in such fields as physics, chemistry, biology, and medicine. Several devices, including optical tweezers, atomic force microscope, micro-pipette aspirator, and standing surface wave type acoustic tweezers have been studied to satisfy this need. However, none of them has been demonstrated to be suitable for in vivo and clinical studies. Single beam acoustic tweezers (SBAT) is a technology that uses highly focused acoustic beam to trap particles toward the beam focus. Its feasibility was first theoretically and experimentally demonstrated by Lee and Shung several years ago. Since then, much effort has been devoted to improving this technology. At present, the tool is capable of trapping a microparticle as small as 1 μm, as well as a single red blood cell. Although in comparing to other microparticles manipulating technologies, SBAT has advantages of providing stronger trapping force and deeper penetration depth in tissues, and producing less tissue damage, its potential for in vivo applications has yet been explored. It is worth noting that ultrasound has been used as a diagnostic tool for over 50 years and no known major adverse effects have been observed at the diagnostic energy level. This paper reports the results of an initial attempt to assess the feasibility of single beam acoustic tweezers to trap microparticles in vivo inside of a blood vessel. The acoustic intensity of SBAT under the trapping conditions that were utilized was measured. The mechanical index and thermal index at the focus of acoustic beam were found to be 0.48 and 0.044, respectively, which meet the standard of commercial diagnostic ultrasound system.

  15. Single-beam measurements of LHC instability threshold in terms of octupole current

    CERN Document Server

    Mounet, N; Buffat, X; Burov, A; Hemelsoet, G; Metral, E; Papotti, G; Pieloni, T; Pojer, M; Salvant, B; Trad, G

    2012-01-01

    This note summarizes two machine development (MD) studies aimed at determining the octupole current needed in the LHC in order to stabilize all headtail instabilities at 4TeV/c, before and after the squeeze, with tight collimator settings, and when a single beam (beam 2) at maximum intensity (1380 bunches, 2.1 1014 protons) is present in the machine. The MDs followed the normal physics operation procedure, at the notable exception that a single beam was used, the other beam containing only one non-colliding nominal bunch. Octupole current (with negative polarity in the focusing octupoles and the opposite in the defocusing ones) was decreased by small steps until the instability threshold was reached. This was performed in two distinct MDs, one before the squeeze and the other after it, testing also several chromaticity values and the effect of the transverse damper in the latter case. Octupole thresholds are shown in each case studied, as well as the rise times of the instabilities observed.

  16. The effects of two counterpropagating surface acoustic wave beams on single electron acoustic charge transport

    International Nuclear Information System (INIS)

    He Jianhong; Guo Huazhong; Song Li; Zhang Wei; Gao Jie; Lu Chuan

    2010-01-01

    We present a comprehensive study of the effects of two counterpropagating surface acoustic waves on the acoustoelectric current of single electron transport devices. A significant improvement in the accuracy of current quantization is achieved as a result of an additional surface acoustic wave beam. The experiments reveal the sinusoidally periodical modulation in the acoustoelectric current characteristic as a function of the relative phase of the two surface acoustic wave beams. Besides, by using standing surface acoustic waves, the acoustoelectric current is detected which we consider as the so-called anomalous acoustoelectric current produced by acoustic wave mechanical deformations. This kind current is contributed to one component of the acoustoelectric current in surface acoustic wave device, which could enable us to establish a more adequate description of acoustoelectric effects on single-electron acoustic charge transport.

  17. Acoustical and optical radiation pressures and the development of single beam acoustical tweezers

    OpenAIRE

    Thomas , Jean-Louis; Marchiano , Régis; Baresch , Diego

    2017-01-01

    International audience; Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and positioned micron size particles, biological samples or even atoms with subnanometer accuracy in three dimens...

  18. Improved single particle potential for transport model simulations of nuclear reactions induced by rare isotope beams

    International Nuclear Information System (INIS)

    Xu Chang; Li Baoan

    2010-01-01

    Taking into account more accurately the isospin dependence of nucleon-nucleon interactions in the in-medium many-body force term of the Gogny effective interaction, new expressions for the single-nucleon potential and the symmetry energy are derived. Effects of both the spin (isospin) and the density dependence of nuclear effective interactions on the symmetry potential and the symmetry energy are examined. It is shown that they both play a crucial role in determining the symmetry potential and the symmetry energy at suprasaturation densities. The improved single-nucleon potential will be useful for more accurate simulation of nuclear reactions induced by rare-isotope beams within transport models.

  19. Anisotropy effect of crater formation on single crystal silicon surface under intense pulsed ion beam irradiation

    Science.gov (United States)

    Shen, Jie; Yu, Xiao; Zhang, Jie; Zhong, Haowen; Cui, Xiaojun; Liang, Guoying; Yu, Xiang; Huang, Wanying; Shahid, Ijaz; Zhang, Xiaofu; Yan, Sha; Le, Xiaoyun

    2018-04-01

    Due to the induced extremely fast thermal and dynamic process, Intense Pulsed Ion Beam (IPIB) is widely applied in material processing, which can bring enhanced material performance and surface craters as well. To investigate the craters' formation mechanism, a specific model was built with Finite Element Methods (FEM) to simulate the thermal field on irradiated single crystal silicon. The direct evidence for the existence of the simulated 6-fold rotational symmetric thermal distribution was provided by electron microscope images obtained on single crystal silicon. The correlation of the experiment and simulation is of great importance to understand the interaction between IPIB and materials.

  20. Investigation of the Dynamics of a Clamped-Clamped Microbeam Near the Third Mode Using a Partial Electrode

    KAUST Repository

    Masri, Karim M.

    2014-08-17

    We present an investigation of the dynamics of a clamped-clamped microbeam excited electrostatically near its third mode. To maximize the response at the third mode, a partial electrode configuration is utilized. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. A shooting method to find the periodic motion is utilized to generate frequency response curves. The curves show hardenining behavior and dynamic pull-in. We show that the dynamic amplitude of the partial configuration is higher than that of a full electrode configuration. These results are promising for the use of higher-order modes for mass detection and for ultra sensitive resonant sensors.

  1. Investigation of the Dynamics of a Clamped-Clamped Microbeam Near the Third Mode Using a Partial Electrode

    KAUST Repository

    Masri, Karim M.; Younis, Mohammad I.

    2014-01-01

    We present an investigation of the dynamics of a clamped-clamped microbeam excited electrostatically near its third mode. To maximize the response at the third mode, a partial electrode configuration is utilized. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. A shooting method to find the periodic motion is utilized to generate frequency response curves. The curves show hardenining behavior and dynamic pull-in. We show that the dynamic amplitude of the partial configuration is higher than that of a full electrode configuration. These results are promising for the use of higher-order modes for mass detection and for ultra sensitive resonant sensors.

  2. Single and multi degree of freedom analysis of steel beams under blast loading

    Energy Technology Data Exchange (ETDEWEB)

    Nassr, Amr A., E-mail: nassraa@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Razaqpur, A. Ghani, E-mail: razaqpu@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Tait, Michael J., E-mail: taitm@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Campidelli, Manuel, E-mail: campide@mcmaster.ca [Dept. of Civil Engineering, McMaster Univ., Hamilton, ON, L8S 4L7 (Canada); Foo, Simon, E-mail: simon.foo@pwgsc.gc.ca [Public Works and Government Services, Gatineau, Quebec (Canada)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Experimentally tested beams under blast are analyzed using SDOF and MDOF models. Black-Right-Pointing-Pointer SDOF model adequately captures the time dependant deformations and internal forces. Black-Right-Pointing-Pointer Constant DIF based on a low strain rate leads to conservative estimate of the DIF. Black-Right-Pointing-Pointer The responses of the test beams are governed by the first mode of vibration. - Abstract: This paper presents detailed analysis of the results of field tests on 13 full scale wide flange steel beams subjected to blast loads generated by the detonation of up to 250 kg of ANFO explosive. The experimental results are analyzed using an equivalent Single-Degree-of-Freedom (SDOF) model of a beam, which includes material nonlinearity and strain rate effects. To account for strain rate effect on beam stiffness and strength, its full moment-curvature response is determined by dividing its cross-section into a number of layers and a strain rate-dependent stress-strain relationship, based on the Cowper-Symonds strain rate model, is used to capture the nonlinear stress distribution over the section. To determine the effects of higher modes of vibration and the variation of beam mechanical properties along its length on its dynamic response, the test beams are also analyzed using a Multi-Degree-of-Freedom (MDOF) model involving beam finite elements. Each element has two nodes and three degrees of freedom and is again divided into a number of layers to capture the strain rate effect and nonlinear stress distribution over its depth. The predicted displacements and strains by the two models are compared with the corresponding experimental data and the results show that for the given beams, the time-dependant deformations, internal forces, and moments can be adequately predicted by either model because the first mode of vibration is found to dominate their response; however, the use of a constant strain rate

  3. Single and multi degree of freedom analysis of steel beams under blast loading

    International Nuclear Information System (INIS)

    Nassr, Amr A.; Razaqpur, A. Ghani; Tait, Michael J.; Campidelli, Manuel; Foo, Simon

    2012-01-01

    Highlights: ► Experimentally tested beams under blast are analyzed using SDOF and MDOF models. ► SDOF model adequately captures the time dependant deformations and internal forces. ► Constant DIF based on a low strain rate leads to conservative estimate of the DIF. ► The responses of the test beams are governed by the first mode of vibration. - Abstract: This paper presents detailed analysis of the results of field tests on 13 full scale wide flange steel beams subjected to blast loads generated by the detonation of up to 250 kg of ANFO explosive. The experimental results are analyzed using an equivalent Single-Degree-of-Freedom (SDOF) model of a beam, which includes material nonlinearity and strain rate effects. To account for strain rate effect on beam stiffness and strength, its full moment-curvature response is determined by dividing its cross-section into a number of layers and a strain rate-dependent stress-strain relationship, based on the Cowper–Symonds strain rate model, is used to capture the nonlinear stress distribution over the section. To determine the effects of higher modes of vibration and the variation of beam mechanical properties along its length on its dynamic response, the test beams are also analyzed using a Multi-Degree-of-Freedom (MDOF) model involving beam finite elements. Each element has two nodes and three degrees of freedom and is again divided into a number of layers to capture the strain rate effect and nonlinear stress distribution over its depth. The predicted displacements and strains by the two models are compared with the corresponding experimental data and the results show that for the given beams, the time-dependant deformations, internal forces, and moments can be adequately predicted by either model because the first mode of vibration is found to dominate their response; however, the use of a constant strain rate through the so-called Dynamic Increase Factor (DIF) can lead to highly conservative estimate of the

  4. Dual aerosol detector based on forward light scattering with a single laser beam

    International Nuclear Information System (INIS)

    Kovach, B.J.; Custer, R.A.; Powers, F.L.; Kovach, A.

    1985-01-01

    The in-place leak testing of HEPA filter banks using a single detector can lead to some error in the measurement due to the fluctuation of the aerosol concentration while the single detector is being switched from the upstream to downstream sampling. The time duration of the test also can cause unnecessarily high DOP loading of the HEPA filters and in some cases higher radiation exposure to the testing personnel. The new forward light scattering detector uses one 632.8 nm laser beam for aerosol detection in a dual chamber sampling and detecting aerosol concentration simultaneously both upstream and downstream. This manner of operation eliminates the errors caused by concentration variations between upstream and downstream sample points while the switching takes place. The new detector uses large area silicone photodiodes with a hole in the center, to permit uninterrupted passage of the laser beam through the downstream sample chamber. The nonlinearity due to the aerosol over population of the laser beam volume is calculated to be less than 1% using a Poisson distribution method to determine the average distance of the particles. A simple pneumatic system prevents mixing of the upstream and downstream samples even in wide pressure variations of the duct system

  5. Electronic properties of single Ge/Si quantum dot grown by ion beam sputtering deposition.

    Science.gov (United States)

    Wang, C; Ke, S Y; Yang, J; Hu, W D; Qiu, F; Wang, R F; Yang, Y

    2015-03-13

    The dependence of the electronic properties of a single Ge/Si quantum dot (QD) grown by the ion-beam sputtering deposition technique on growth temperature and QD diameter is investigated by conductive atomic force microscopy (CAFM). The Si-Ge intermixing effect is demonstrated to be important for the current distribution of single QDs. The current staircase induced by the Coulomb blockade effect is observed at higher growth temperatures (>700 °C) due to the formation of an additional barrier between dislocated QDs and Si substrate for the resonant tunneling of holes. According to the proposed single-hole-tunneling model, the fact that the intermixing effect is observed to increase as the incoherent QD size decreases may explain the increase in the starting voltage of the current staircase and the decrease in the current step width.

  6. Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

    International Nuclear Information System (INIS)

    Yanch, Jacquelyn C.

    2004-01-01

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

  7. Xe ion beam induced rippled structures on differently oriented single-crystalline Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan [Forschungszentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, PO Box 510119, 01314 Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich, E-mail: A.Hanisch@fzd.d [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany)

    2010-03-24

    We report on Xe{sup +} induced ripple formation at medium energy on single-crystalline silicon surfaces of different orientations using substrates with an intentional miscut from the [0 0 1] direction and a [1 1 1] oriented wafer. The ion beam incidence angle with respect to the surface normal was kept fixed at 65{sup 0} and the ion beam projection was parallel or perpendicular to the [1 1 0] direction. By a combination of atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy we found that the features of the surface and subsurface rippled structures such as ripple wavelength and amplitude and the degree of order do not depend on the surface orientation as assumed in recent models of pattern formation for semiconductor surfaces. (fast track communication)

  8. A simulation study on the dose distribution for a single beam of the gamma knife

    International Nuclear Information System (INIS)

    Chen, Chin-cheng; Jiang, Shiang-Huei; Lee, Chung-chi; Shiau, Cheng-Ying

    2000-01-01

    The purpose of this study is to evaluate the impact of the tissue heterogeneity on the dose distribution for a single beam of the gamma knife. The EGS4 Monte Carlo code was used to simulate both depth and radial profiles of the radiation dose in homogeneous and heterogeneous phantoms, respectively. The results are compared with the dose distribution calculated using the mathematical model of Gamma Plan, the treatment planning system of the gamma knife. The skull and sinus heterogeneity were simulated by a Teflon shell and an air shell, respectively. It was found that the tissue heterogeneity caused significant perturbation on the absolute depth dose at the focus as well as on the depth-dose distribution near the phantom surface and/or at the interface but little effect on the radial dose distribution. The effect of the beam aperture on the depth-dose distribution was also investigated in this study. (author)

  9. Characterization of a synthetic single crystal diamond Schottky diode for radiotherapy electron beam dosimetry.

    Science.gov (United States)

    Di Venanzio, C; Marinelli, Marco; Milani, E; Prestopino, G; Verona, C; Verona-Rinati, G; Falco, M D; Bagalà, P; Santoni, R; Pimpinella, M

    2013-02-01

    To investigate the dosimetric properties of synthetic single crystal diamond based Schottky diodes under irradiation with therapeutic electron beams from linear accelerators. A single crystal diamond detector was fabricated and tested under 6, 8, 10, 12, and 15 MeV electron beams. The detector performances were evaluated using three types of commercial detectors as reference dosimeters: an Advanced Markus plane parallel ionization chamber, a Semiflex cylindrical ionization chamber, and a p-type silicon detector. Preirradiation, linearity with dose, dose rate dependence, output factors, lateral field profiles, and percentage depth dose profiles were investigated and discussed. During preirradiation the diamond detector signal shows a weak decrease within 0.7% with respect to the plateau value and a final signal stability of 0.1% (1σ) is observed after about 5 Gy. A good linear behavior of the detector response as a function of the delivered dose is observed with deviations below ±0.3% in the dose range from 0.02 to 10 Gy. In addition, the detector response is dose rate independent, with deviations below 0.3% in the investigated dose rate range from 0.17 to 5.45 Gy∕min. Percentage depth dose curves obtained from the diamond detector are in good agreement with the ones from the reference dosimeters. Lateral beam profile measurements show an overall good agreement among detectors, taking into account their respective geometrical features. The spatial resolution of solid state detectors is confirmed to be better than that of ionization chambers, being the one from the diamond detector comparable to that of the silicon diode. A good agreement within experimental uncertainties was also found in terms of output factor measurements between the diamond detector and reference dosimeters. The observed dosimetric properties indicate that the tested diamond detector is a suitable candidate for clinical electron beam dosimetry.

  10. Annular spherically focused ring transducers for improved single-beam acoustical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Mitri, F. G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology—ETC, Santa Fe, New Mexico 87508 (United States)

    2016-02-14

    The use of ultrasonic transducers with a central hollow is suggested for improved single-beam acoustical tweezers applications. Within the framework of the Fresnel-Kirchhoff parabolic approximation, a closed-form partial-wave series expansion (PWSE) for the incident velocity potential (or pressure) field is derived for an annular spherically focused ring (asfr) with uniform vibration across its surface in spherical coordinates. The Rayleigh-Sommerfeld diffraction integral and the addition theorems for the Legendre and spherical wave functions are used to obtain the PWSE assuming a weakly focused beam (with a focusing angle α ≤ 20°). The PWSE allows evaluating the incident field from the finite asfr in 3D. Moreover, the obtained solution allows computing efficiently the acoustic scattering and radiation force on a sphere centered on the beam's axis of wave propagation. The analytical solution is valid for wavelengths largely exceeding the radius of the asfr and when the viscosity of the surrounding fluid can be neglected. Numerical predictions for the beam-forming, scattering, and axial time-averaged radiation force are performed with particular emphasis on the asfr thickness, the axial distance separating the sphere from the center of the transducer, the (non-dimensional) size of the transducer, as well as the sphere's elastic properties without restriction to the long- (i.e., Rayleigh) or the short-wavelength (i.e., ray acoustics) regimes. Potential applications of the present solution are in beam-forming design, particle tweezing, and manipulation due to negative forces using ultrasonic asfr transducers.

  11. The cardiovascular effects of aortic clamping and unclamping

    African Journals Online (AJOL)

    aortic clamping is that afterload and blood pressure increase, and ... individually, albeit they interact with each other. The degree of ... position of the aortic clamp, the greater the increase ... the increase in preload in response to aortic clamping.

  12. Experimental and analytical parametric study of single-crystal unimorph beams for vibration energy harvesting.

    Science.gov (United States)

    Karami, M Amin; Bilgen, Onur; Inman, Daniel J; Friswell, Michael I

    2011-07-01

    This research presents an experimental and theoretical energy harvesting characterization of beam-like, uniform cross-section, unimorph structures employing single-crystal piezoelectrics. Different piezoelectric materials, substrates, and configurations are examined to identify the best design configuration for lightweight energy harvesting devices for low-power applications. Three types of piezoelectrics (singlecrystal PMN-PZT, polycrystalline PZT-5A, and PZT-5H-type monolithic ceramics) are evaluated in a unimorph cantilevered beam configuration. The devices have been excited by harmonic base acceleration. All of the experimental characteristics have been used to validate an exact electromechanical model of the harvester. The study shows the optimum choice of substrate material for single-crystal piezoelectric energy harvesting. Comparison of energy scavengers with stainless steel substrates reveals that single-crystal harvesters produce superior power compared with polycrystalline devices. To further optimize the power harvesting, we study the relation between the thickness of the substrate and the power output for different substrate materials. The relation between power and substrate thickness profoundly varies among different substrate materials. The variation is understood by examining the change of mechanical transmissibility and the variations of the coupling figure of merit of the harvesters with thickness ratio. The investigation identifies the optimal thickness of the substrate for different substrate materials. The study also shows that the densities of the substrates and their mechanical damping coefficients have significant effects on the power output.

  13. Intensity-gradient induced Sisyphus cooling of a single atom in a localized hollow-beam trap

    International Nuclear Information System (INIS)

    Yin, Yaling; Xia, Yong; Ren, Ruimin; Du, Xiangli; Yin, Jianping

    2015-01-01

    In order to realize a convenient and efficient laser cooling of a single atom, we propose a simple and promising scheme to cool a single neutral atom in a blue-detuned localized hollow-beam trap by intensity-gradient induced Sisyphus cooling, and study the dynamic process of the intensity-gradient cooling of a single 87 Rb atom in the localized hollow-beam trap by using Monte-Carlo simulations. Our study shows that a single 87 Rb atom with a temperature of 120 μK from a magneto-optical trap (MOT) can be directly cooled to a final temperature of 4.64 μK in our proposed scheme. We also investigate the dependences of the cooling results on the laser detuning δ of the localized hollow-beam, the power RP 0 of the re-pumping laser beam, the sizes of both the localized hollow-beam and the re-pumping beam, and find that there is a pair of optimal cooling parameters (δ and RP 0 ) for an expected lowest temperature, and the cooling results strongly depend on the size of the re-pumping beam, but weakly depend on the size of the localized hollow-beam. Finally, we further study the cooling potential of our localized hollow-beam trap for the initial temperature of a single atom, and find that a single 87 Rb atom with an initial temperature of higher than 1 mK can also be cooled directly to about 6.6 μK. (paper)

  14. Spectrum sensing using single-radio switched-beam antenna systems

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Wilcox, David; De Carvalho, Elisabeth

    2012-01-01

    of the reactive loads rotate the narrowband beampattern to different angular positions dividing the whole space around the cognitive receiver into several angular subspaces. The beampattern directionality leverages the performance of spectrum sensing algorithms like the energy detection by enhancing the receive......The paper describes spectrum sensing using single-radio switched-beam arrays with reactance-loaded parasitic elements. At a given frequency, the antenna's loading conditions (reactive loads) are optimized for maximum average beamforming gain in the beampattern look direction. Circular permutations...

  15. Using the in situ lift-out technique to prepare TEM specimens on a single-beam FIB instrument

    International Nuclear Information System (INIS)

    Lekstrom, M; McLachlan, M A; Husain, S; McComb, D W; Shollock, B A

    2008-01-01

    Transmission electron microscope (TEM) specimens are today routinely prepared using focussed ion beam (FIB) instruments. Specifically, the lift-out method has become an increasingly popular technique and involves removing thin cross-sections from site-specific locations and transferring them to a TEM grid. This lift-out process can either be performed ex situ or in situ. The latter is mainly carried out on combined dual-beam FIB and scanning electron microscope (SEM) systems whereas conventional single-beam instruments often are limited to the traditional ex situ method. It is nevertheless desirable to enhance the capabilities of existing single-beam instruments to allow for in situ lift-out preparation to be performed since this technique offers a number of advantages over the older ex situ method. A single-beam FIB instrument was therefore modified to incorporate an in situ micromanipulator fitted with a tungsten needle, which can be attached to a cut-out FIB section using ion beam induced platinum deposition. This article addresses the issues of using an ion beam to monitor the in situ manipulation process as well as approaches that can be used to create stronger platinum welds between two objects, and finally, views on how to limit the extent of ion beam damage to the specimen surface.

  16. Mechanics of wafer bonding: Effect of clamping

    Science.gov (United States)

    Turner, K. T.; Thouless, M. D.; Spearing, S. M.

    2004-01-01

    A mechanics-based model is developed to examine the effects of clamping during wafer bonding processes. The model provides closed-form expressions that relate the initial geometry and elastic properties of the wafers to the final shape of the bonded pair and the strain energy release rate at the interface for two different clamping configurations. The results demonstrate that the curvature of bonded pairs may be controlled through the use of specific clamping arrangements during the bonding process. Furthermore, it is demonstrated that the strain energy release rate depends on the clamping configuration and that using applied loads usually leads to an undesirable increase in the strain energy release rate. The results are discussed in detail and implications for process development and bonding tool design are highlighted.

  17. Formal Design Review Foot Clamp Modification

    International Nuclear Information System (INIS)

    OTEN, T.C.

    2000-01-01

    This report documents the Design Review performed for the foot clamp modification. The report documents the acceptability of the design, identifies the documents that were reviewed, the scope of the review and the members of the review team

  18. Core clamping device for a nuclear reactor

    International Nuclear Information System (INIS)

    Guenther, R.W.

    1974-01-01

    The core clamping device for a fast neutron reactor includes clamps to support the fuel zone against the pressure vessel. The clamps are arranged around the circumference of the core. They consist of torsion bars arranged parallel at some distance around the core with lever arms attached to the ends whose force is directed in the opposite direction, pressing against the wall of the pressure vessel. The lever arms and pressure plates also actuated by the ends of the torsion bars transfer the stress, the pressure plates acting upon the fuel elements or fuel assemblies. Coupling between the ends of the torsion bars and the pressure plates is achieved by end carrier plates directly attached to the torsion bars and radially movable. This clamping device follows the thermal expansions of the core, allows specific elements to be disengaged in sections and saves space between the core and the neutron reflectors. (DG) [de

  19. Acoustical tweezers using single spherically focused piston, X-cut, and Gaussian beams.

    Science.gov (United States)

    Mitri, Farid G

    2015-10-01

    Partial-wave series expansions (PWSEs) satisfying the Helmholtz equation in spherical coordinates are derived for circular spherically focused piston (i.e., apodized by a uniform velocity amplitude normal to its surface), X-cut (i.e., apodized by a velocity amplitude parallel to the axis of wave propagation), and Gaussian (i.e., apodized by a Gaussian distribution of the velocity amplitude) beams. The Rayleigh-Sommerfeld diffraction integral and the addition theorems for the Legendre and spherical wave functions are used to obtain the PWSEs assuming weakly focused beams (with focusing angle α ⩽ 20°) in the Fresnel-Kirchhoff (parabolic) approximation. In contrast with previous analytical models, the derived expressions allow computing the scattering and acoustic radiation force from a sphere of radius a without restriction to either the Rayleigh (a ≪ λ, where λ is the wavelength of the incident radiation) or the ray acoustics (a ≫λ) regimes. The analytical formulations are valid for wavelengths largely exceeding the radius of the focused acoustic radiator, when the viscosity of the surrounding fluid can be neglected, and when the sphere is translated along the axis of wave propagation. Computational results illustrate the analysis with particular emphasis on the sphere's elastic properties and the axial distance to the center of the concave surface, with close connection of the emergence of negative trapping forces. Potential applications are in single-beam acoustical tweezers, acoustic levitation, and particle manipulation.

  20. Moment-Curvature Behaviors of Concrete Beams Singly Reinforced by Steel-FRP Composite Bars

    Directory of Open Access Journals (Sweden)

    Zeyang Sun

    2017-01-01

    Full Text Available A steel-fiber-reinforced polymer (FRP composite bar (SFCB is a kind of rebar with inner steel bar wrapped by FRP, which can achieve a better anticorrosion performance than that of ordinary steel bar. The high ultimate strength of FRP can also provide a significant increase in load bearing capacity. Based on the adequate simulation of the load-displacement behaviors of concrete beams reinforced by SFCBs, a parametric analysis of the moment-curvature behaviors of concrete beams that are singly reinforced by SFCB was conducted. The critical reinforcement ratio for differentiating the beam’s failure mode was presented, and the concept of the maximum possible peak curvature (MPPC was proposed. After the ultimate curvature reached MPPC, it decreased with an increase in the postyield stiffness ratio (rsf, and the theoretical calculation method about the curvatures before and after the MPPC was derived. The influence of the reinforcement ratio, effective depth, and FRP ultimate strain on the ultimate point was studied by the dimensionless moment and curvature. By calculating the envelope area under the moment-curvature curve, the energy ductility index can obtain a balance between the bearing capacity and the deformation ability. This paper can provide a reference for the design of concrete beams that are reinforced by SFCB or hybrid steel bar/FRP bar.

  1. Single track coincidence measurements of fluorescent and plastic nuclear track detectors in therapeutic carbon beams

    International Nuclear Information System (INIS)

    Osinga, J-M; Jäkel, O; Ambrožová, I; Brabcová, K Pachnerová; Davídková, M; Akselrod, M S; Greilich, S

    2014-01-01

    In this paper we present a method for single track coincidence measurements using two different track detector materials. We employed plastic and fluorescent nuclear track detectors (PNTDs and FNTDs) in the entrance channel of a monoenergetic carbon ion beam covering the therapeutic energy range from 80 to 425 MeV/u. About 99% of all primary particle tracks detected by both detectors were successfully matched, while 1% of the particles were only detected by the FNTDs because of their superior spatial resolution. We conclude that both PNTDs and FNTDs are suitable for clinical carbon beam dosimetry with a detection efficiency of at least 98.82% and 99.83% respectively, if irradiations are performed with low fluence in the entrance channel of the ion beam. The investigated method can be adapted to other nuclear track detectors and offers the possibility to characterize new track detector materials against well-known detectors. Further, by combining two detectors with a restricted working range in the presented way a hybrid-detector system can be created with an extended and optimized working range

  2. The Effect of an Added Mass on the Frequency Shifts of a Clamped-Clamped Microbeam for Bio-Mass Detection

    KAUST Repository

    Bouchaala, Adam M.; Nayfeh, Ali H.; Younis, Mohammad I.

    2016-01-01

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped-clamped microbeams due to an added mass. Based on the Euler-Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes.

  3. The Effect of an Added Mass on the Frequency Shifts of a Clamped-Clamped Microbeam for Bio-Mass Detection

    KAUST Repository

    Bouchaala, Adam M.

    2016-12-05

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped-clamped microbeams due to an added mass. Based on the Euler-Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes.

  4. An isolated Hda-clamp complex is functional in the regulatory inactivation of DnaA and DNA replication.

    Science.gov (United States)

    Kawakami, Hironori; Su'etsugu, Masayuki; Katayama, Tsutomu

    2006-10-01

    In Escherichia coli, a complex consisting of Hda and the DNA-loaded clamp-subunit of the DNA polymerase III holoenzyme promotes hydrolysis of DnaA-ATP. The resultant ADP-DnaA is inactive for initiation of chromosomal DNA replication, thereby repressing excessive initiations. As the cellular content of the clamp is 10-100 times higher than that of Hda, most Hda molecules might be complexed with the clamp in vivo. Although Hda predominantly forms irregular aggregates when overexpressed, in the present study we found that co-overexpression of the clamp with Hda enhances Hda solubility dramatically and we efficiently isolated the Hda-clamp complex. A single molecule of the complex appears to consist of two Hda molecules and a single clamp. The complex is competent in DnaA-ATP hydrolysis and DNA replication in the presence of DNA and the clamp deficient subassembly of the DNA polymerase III holoenzyme (pol III*). These findings indicate that the clamp contained in the complex is loaded onto DNA through an interaction with the pol III* and that the Hda activity is preserved in these processes. The complex consisting of Hda and the DNA-unloaded clamp may play a specific role in a process proceeding to the DnaA-ATP hydrolysis in vivo.

  5. Single-bunch beam loading on the SLAC two-mile accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.

    1976-05-01

    The experiments described were initially prompted by interest in the radiation loss of relativistic electron rings passing through periodic structures. Later the same experiments became relevant to the theory of energy loss of electrons in large storage rings. In both of these cases energy loss to the higher order modes of the respective structures could seriously limit their effective operation. In these experiments, single bunches of electrons with intensities up to 7 x 10 8 electrons per bunch are accelerated through the SLAC three-kilometer accelerator, and their energy spectra are analyzed. Early experiments over a wide energy range (900 MeV to 19 GeV) demonstrated that the energy loss was proportional to the total charge in the bunch but was independent of beam energy. The average energy loss of a single bunch normalized to 10 9 electrons was initially measured to be 38 MeV

  6. Focused ion beam patterning to dielectrophoretically assemble single nanowire based devices

    International Nuclear Information System (INIS)

    La Ferrara, V; Massera, E; Francia, G Di; Alfano, B

    2010-01-01

    Direct-write processing is increasingly taking place in nanodevice fabrication. In this work, Focused Ion Beam (FIB), a powerful tool in maskless micromachining, is used for electrode patterning onto a silicon/silicon nitride substrate. Then a single palladium nanowire is assembled between electrodes by means of dielectrophoresis (DEP). The nanowire morphology depends on the electrode pattern when DEP conditions are fixed. FIB/DEP combination overcomes the problem of nanowire electrical contamination due to gallium ion bombardment and the as-grown nanowire retains its basic electrical properties. Single nanowire based devices have been fabricated with this novel approach and have been tested as hydrogen sensors, confirming the reliability of this technology.

  7. Selective Arterial Clamping Versus Hilar Clamping for Minimally Invasive Partial Nephrectomy.

    Science.gov (United States)

    Yezdani, Mona; Yu, Sue-Jean; Lee, David I

    2016-05-01

    Partial nephrectomy has become an accepted treatment of cT1 renal masses as it provides improved long-term renal function compared to radical nephrectomy (Campbell et al. J Urol. 182:1271-9, 2009). Hilar clamping is utilized to help reduce bleeding and improve visibility during tumor resection. However, concern over risk of kidney injury with hilar clamping has led to new techniques to reduce length of warm ischemia time (WIT) during partial nephrectomy. These techniques have progressed over the years starting with early hilar unclamping, controlled hypotension during tumor resection, selective arterial clamping, minimal margin techniques, and off-clamp procedures. Selective arterial clamping has progressed significantly over the years. The main question is what are the exact short- and long-term renal effects from increasing clamp time. Moreover, does it make sense to perform these more time-consuming or more complex procedures if there is no long-term preservation of kidney function? More recent studies have shown no difference in renal function 6 months from surgery when selective arterial clamping or even hilar clamping is employed, although there is short-term improved decline in estimated glomerular filtration rate (eGFR) with selective clamping and off-clamp techniques (Komninos et al. BJU Int. 115:921-8, 2015; Shah et al. 117:293-9, 2015; Kallingal et al. BJU Int. doi: 10.1111/bju.13192, 2015). This paper reviews the progression of total hilar clamping to selective arterial clamping (SAC) and the possible difference its use makes on long-term renal function. SAC may be attempted based on surgeon's decision-making, but may be best used for more complex, larger, more central or hilar tumors and in patients who have renal insufficiency at baseline or a solitary kidney.

  8. Single bunch beam loading on the SLAC three-kilometer accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.; Loew, G.A.; Miller, R.H.; Wilson, P.B.

    1977-03-01

    Since the report on single bunch beam loading experiments at SLAC at the 1975 Particle Accelerator Conference, it has been possible to obtain a much better understanding and agreement of theoretical and experimental results related to this problem. These improvements were made possible by two developments: the generation of a ''wake-field'' function for the SLAC 3-km slow-wave structure and the use of this function to calculate single bunch energy spectra. The wake-field function which gives the time decay of the fields generated by the passage of a delta-function beam was derived by summing all the TM cylindrically symmetrical modes of an equivalent accelerator cavity. By multiplying this wake-field function by a measured bunch density function and integrating along the bunch, it is possible to calculate the energy of each electron in the bunch. This in turn enables one to predict the energy spectrum for any given phase angle of the bunch with respect to the crest of the rf accelerating wave. Agreement between these calculations and experimental measurements is very good. These results are presented, and the possible sources of some of the remaining discrepancies are discussed

  9. Single bunch beam loading on the SLAC three-kilometer accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.; Loew, G.A.; Miller, R.H.; Wilson, P.B.

    1977-01-01

    Since the report on single bunch beam loading experiments at SLAC at the 1975 Particle Accelerator Conference, it has been possible to obtain a much better understanding and agreement of theoretical and experimental results related to this problem. These improvements have been made possible by two developments: the generation of a ''wake-field'' function for the SLAC 3-km slow-wave structure and the use of this function to calculate single bunch energy spectra. The wake-field function which gives the time decay of the fields generated by the passage of a delta-function beam was derived by summing all the TM cylindrically symmetrical modes of an equivalent accelerator cavity. By multiplying this wake-field function by a measured bunch density function and integrating along the bunch, it is possible to calculate the energy of each electron in the bunch. This in turn enables one to predict the energy spectrum for any given phase angle of the bunch with respect to the crest of the rf accelerating wave. Agreement between these calculations and experimental measurements is very good. These results are presented and the possible sources of some of the remaining discrepancies are discussed

  10. Commissioning of the ATLAS High Level Trigger with single beam and cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Di Mattia, A, E-mail: dimattia@mail.cern.c [Michigan State University - Department of Physics and Astronomy 3218 Biomedical Physical Science - East Lansing, MI 48824-2320 (United States)

    2010-04-01

    ATLAS is one of the two general-purpose detectors at the Large Hadron Collider (LHC). The trigger system is responsible for making the online selection of interesting collision events. At the LHC design luminosity of 10{sup 34} cm{sup -2}s{sup -1} it will need to achieve a rejection factor of the order of 10{sup -7} against random proton-proton interactions, while selecting with high efficiency events that are needed for physics analyses. After a first processing level using custom electronics based on FPGAs and ASICs, the trigger selection is made by software running on two processor farms, containing a total of around two thousand multi-core machines. This system is known as the High Level Trigger (HLT). To reduce the network data traffic and the processing time to manageable levels, the HLT uses seeded, step-wise reconstruction, aiming at the earliest possible rejection of background events. The recent LHC startup and short single-beam run provided a 'stress test' of the system and some initial calibration data. Following this period, ATLAS continued to collect cosmic-ray events for detector alignment and calibration purposes. After giving an overview of the trigger design and its innovative features, this paper focuses on the experience gained from operating the ATLAS trigger with single LHC beams and cosmic-rays.

  11. Commissioning of the ATLAS High Level Trigger with single beam and cosmic rays

    International Nuclear Information System (INIS)

    Di Mattia, A

    2010-01-01

    ATLAS is one of the two general-purpose detectors at the Large Hadron Collider (LHC). The trigger system is responsible for making the online selection of interesting collision events. At the LHC design luminosity of 10 34 cm -2 s -1 it will need to achieve a rejection factor of the order of 10 -7 against random proton-proton interactions, while selecting with high efficiency events that are needed for physics analyses. After a first processing level using custom electronics based on FPGAs and ASICs, the trigger selection is made by software running on two processor farms, containing a total of around two thousand multi-core machines. This system is known as the High Level Trigger (HLT). To reduce the network data traffic and the processing time to manageable levels, the HLT uses seeded, step-wise reconstruction, aiming at the earliest possible rejection of background events. The recent LHC startup and short single-beam run provided a 'stress test' of the system and some initial calibration data. Following this period, ATLAS continued to collect cosmic-ray events for detector alignment and calibration purposes. After giving an overview of the trigger design and its innovative features, this paper focuses on the experience gained from operating the ATLAS trigger with single LHC beams and cosmic-rays.

  12. Different methods of hilar clamping during partial nephrectomy: Impact on renal function.

    Science.gov (United States)

    Lee, Jeong Woo; Kim, Hwanik; Choo, Minsoo; Park, Yong Hyun; Ku, Ja Hyeon; Kim, Hyeon Hoe; Kwak, Cheol

    2014-03-01

    To evaluate the impact of different hilar clamping methods on changes in renal function after partial nephrectomy. We analyzed the clinical data of 369 patients who underwent partial nephrectomy for a single renal tumor of size ≤4.0 cm and a normal contralateral kidney. Patients were separated into three groups depending on hilar clamping method: non-clamping, cold ischemia and warm ischemia. Estimated glomerular filtration rate was examined at preoperative, nadir and 1 year postoperatively. Percent change in estimated glomerular filtration rate was used as the parameter to assess the renal functional outcome. Percent change in nadir estimated glomerular filtration rate in the non-clamping group was significantly less compared with the cold ischemia and warm ischemia groups (P hilar clamping (both warm ischemia and cold ischemia) were significantly associated with percent change in nadir estimated glomerular filtration rate, but not in 1-year estimated glomerular filtration rate. Non-clamping partial nephrectomy results in a lower percent change in nadir estimated glomerular filtration rate, whereas it carries an estimated glomerular filtration rate change at 1 year that is similar to partial nephrectomy with cold ischemia and warm ischemia. Cold ischemia and warm ischemia provide a similar effect on renal function. Therefore, when hilar clamping is required, minimization of ischemia time is necessary. © 2013 The Japanese Urological Association.

  13. A missing factor in chip-based patch clamp assay: gigaseal

    International Nuclear Information System (INIS)

    Ong, W-L; Yobas, L; Ong, W-Y

    2006-01-01

    The 'gold' standard in the study of ionic currents across biological membranes is the Patch Clamp method. However, this is a slow, labor and skill intensive process. High throughput patch clamp devices are mainly chip-based. A major challenge in these miniaturized devices is the low rate of 'Gigaseal' formation which is critical in the study of Single Channel effect. In a conventional patch clamp, a pipette moves and patches a fixed cell (cell-adhered patch) which is grown on the bottom of a Petri dish. In the chip-based case, the cells are in suspension and move towards the fixed patch clamp sites (cell-suspended patch). In this study, using the proven conventional patch clamp setup, we investigated the effect of the differences in the cell configurations between the convention patch clamp and cell-based patch clamp. It is shown that adhered cells (as used in the conventional setup) have a much higher rate of gigaseal formation as compared to the cells in suspension (as used in chip-based devices). We postulate that the arrangement of the cytoskeleton within the cell plays a major part in the formation of the gigaseal

  14. An adjustable multi-scale single beam acoustic tweezers based on ultrahigh frequency ultrasonic transducer.

    Science.gov (United States)

    Chen, Xiaoyang; Lam, Kwok Ho; Chen, Ruimin; Chen, Zeyu; Yu, Ping; Chen, Zhongping; Shung, K Kirk; Zhou, Qifa

    2017-11-01

    This paper reports the fabrication, characterization, and microparticle manipulation capability of an adjustable multi-scale single beam acoustic tweezers (SBAT) that is capable of flexibly changing the size of "tweezers" like ordinary metal tweezers with a single-element ultrahigh frequency (UHF) ultrasonic transducer. The measured resonant frequency of the developed transducer at 526 MHz is the highest frequency of piezoelectric single crystal based ultrasonic transducers ever reported. This focused UHF ultrasonic transducer exhibits a wide bandwidth (95.5% at -10 dB) due to high attenuation of high-frequency ultrasound wave, which allows the SBAT effectively excite with a wide range of excitation frequency from 150 to 400 MHz by using the "piezoelectric actuator" model. Through controlling the excitation frequency, the wavelength of ultrasound emitted from the SBAT can be changed to selectively manipulate a single microparticle of different sizes (3-100 μm) by using only one transducer. This concept of flexibly changing "tweezers" size is firstly introduced into the study of SBAT. At the same time, it was found that this incident ultrasound wavelength play an important role in lateral trapping and manipulation for microparticle of different sizes. Biotechnol. Bioeng. 2017;114: 2637-2647. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  15. Short-wavelength soft-x-ray laser pumped in double-pulse single-beam non-normal incidence

    International Nuclear Information System (INIS)

    Zimmer, D.; Ros, D.; Guilbaud, O.; Habib, J.; Kazamias, S.; Zielbauer, B.; Bagnoud, V.; Ecker, B.; Aurand, B.; Kuehl, T.; Hochhaus, D. C.; Neumayer, P.

    2010-01-01

    We demonstrated a 7.36 nm Ni-like samarium soft-x-ray laser, pumped by 36 J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.

  16. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical head holder (skull clamp). 882.4460... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures. (b...

  17. Piezoresistive cantilever force-clamp system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Goodman, Miriam B. [Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305 (United States)

    2011-04-15

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  18. Single Shot Measurements of the 4-Dimensional Transverse Phase Space Distribution of Intense Ion Beams at the UNILAC at GSI

    CERN Document Server

    Groening, L

    2003-01-01

    The UNILAC is used as an injector for the synchrotron SIS. It is designed to fill the synchrotron up to its space charge limit. The upper limit for the useful beam emittance of the UNILAC is given by the finite acceptance of the SIS during the injection process. In order to remain within this acceptance the emittance growth during beam acceleration and transportation due to space charge effects must be minimized by applying an appropriate beam focusing. Therefore, the influence of the magnetic focusing strength on the beam emittance growth was investigated experimentally for different beam currents. Measurements of transverse phase space distributions were performed before and after the Alvarez accelerator with a periodic focusing channel, respectively. In order to perform such a wide parameter scan within a reasonable time with respect to machine stability, the pepper pot technique was applied. The pepper pot method allows for single-pulse measurements. For comparison several measurements using the slit-grid...

  19. Radical distributions in ammonium tartrate single crystals exposed to photon and neutron beams

    International Nuclear Information System (INIS)

    Marrale, M.; Longo, A.; Brai, M.; Barbon, A.; Brustolon, M.

    2014-01-01

    The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these particles when compared with the photon beams. In this work some preliminary results on the analysis of the spatial distributions of the free radicals produced after exposure of ammonium tartrate crystals to various radiation beams ( 60 Co gamma photons and thermal neutrons) were reported. Electron spin resonance analyses were performed by the electron spin echo technique, which allows the determination of local spin concentrations and by double electron-electron resonance technique, which is able to measure the spatial distance distribution (range 1.5-8 nm) among pairs of radicals in solids. The results of these analyses are discussed on the basis of the different distributions of free radicals produced by the two different radiation beams used. This paper extends to the single crystal case, a similar work done on AT powder irradiated with different beams, with assessment of microscopic radical concentration by determining the amount of ID contribution and obtaining the inter-radical distance distributions by double microwave irradiation. In this paper single crystals of AT have been exposed to 60 Co photons and neutrons. The results confirm that advanced pulse EPR techniques allow the direct measurement of the local free radical concentration and provide information about the

  20. Scatter measurement and correction method for cone-beam CT based on single grating scan

    Science.gov (United States)

    Huang, Kuidong; Shi, Wenlong; Wang, Xinyu; Dong, Yin; Chang, Taoqi; Zhang, Hua; Zhang, Dinghua

    2017-06-01

    In cone-beam computed tomography (CBCT) systems based on flat-panel detector imaging, the presence of scatter significantly reduces the quality of slices. Based on the concept of collimation, this paper presents a scatter measurement and correction method based on single grating scan. First, according to the characteristics of CBCT imaging, the scan method using single grating and the design requirements of the grating are analyzed and figured out. Second, by analyzing the composition of object projection images and object-and-grating projection images, the processing method for the scatter image at single projection angle is proposed. In addition, to avoid additional scan, this paper proposes an angle interpolation method of scatter images to reduce scan cost. Finally, the experimental results show that the scatter images obtained by this method are accurate and reliable, and the effect of scatter correction is obvious. When the additional object-and-grating projection images are collected and interpolated at intervals of 30 deg, the scatter correction error of slices can still be controlled within 3%.

  1. Generation and characterization of ultra-short electron beams for single spike infrared FEL radiation at SPARC_LAB

    Science.gov (United States)

    Villa, F.; Anania, M. P.; Artioli, M.; Bacci, A.; Bellaveglia, M.; Bisesto, F. G.; Biagioni, A.; Carpanese, M.; Cardelli, F.; Castorina, G.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Croia, M.; Curcio, A.; Dattoli, G.; Gallo, A.; Di Giovenale, D.; Di Palma, E.; Di Pirro, G.; Ferrario, M.; Filippi, F.; Giannessi, L.; Giribono, A.; Marocchino, A.; Massimo, F.; Mostacci, A.; Petralia, A.; Petrarca, M.; Petrillo, V.; Piersanti, L.; Pioli, S.; Pompili, R.; Romeo, S.; Rossi, A. R.; Scifo, J.; Shpakov, V.; Vaccarezza, C.

    2017-09-01

    The technique for producing and measuring few tens of femtosecond electron beams, and the consequent generation of few tens femtoseconds single spike FEL radiation pulses at SPARC_LAB is presented. The undulator has been used in the double role of radiation source and diagnostic tool for the characterization of the electron beam. The connection between the electron bunch length and the radiation bandwidth is analyzed.

  2. Continuous single pulse resolved measurement of beam diameters at 200 kHz using optical transmission filters

    Science.gov (United States)

    Fruechtenicht, Johannes; Letsch, Andreas; Voss, Andreas; Abdou Ahmed, Marwan; Graf, Thomas

    2012-02-01

    We present a novel laser beam measurement setup which allows the determination of the beam diameter for each single pulse of a pulsed laser beam at repetition rates of up to 200 kHz. This is useful for online process-parameter control e.g. in micromachining or for laser source characterization. Basically, the developed instrument combines spatial transmission filters specially designed for instantaneous optical determination of the second order moments of the lateral intensity distribution of the light beam and photodiodes coupled to customized electronics. The acquisition is computer-based, enabling real-time operation for online monitoring or control. It also allows data storage for a later analysis and visualization of the measurement results. The single-pulse resolved beam diameter can be measured and recorded without any interruption for an unlimited number of pulses. It is only limited by the capacity of the data storage means. In our setup a standard PC and hard-disk provided 2 hours uninterrupted operation and recording of varying beam diameters at 200 kHz. This is about three orders of magnitude faster than other systems. To calibrate our device we performed experiments in cw and pulsed regimes and the obtained results were compared to those obtained with a commercial camera based system. Only minor deviations of the beam diameter values between the two instruments were observed, proving the reliability of our approach.

  3. Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kissinger, Thomas; Charrett, Thomas O. H.; James, Stephen W.; Tatam, Ralph P., E-mail: r.p.tatam@cranfield.ac.uk [Engineering Photonics, Cranfield University, Cranfield, MK43 0AL (United Kingdom); Adams, Alvin; Twin, Andrew [Oxford Instruments Nanoscience, Tubney Woods, Abingdon, Oxon, OX13 5QX (United Kingdom)

    2016-06-28

    A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm · Hz{sup −05}. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.

  4. Focused ion beam milling of nanocavities in single colloidal particles and self-assembled opals

    International Nuclear Information System (INIS)

    Woldering, Leon A; Otter, A M; Husken, Bart H; Vos, Willem L

    2006-01-01

    We present a new method of realizing single nanocavities in individual colloidal particles on the surface of silicon dioxide artificial opals using a focused ion beam milling technique. We show that both the radius and the position of the nanocavity can be controlled with nanometre precision, to radii as small as 40 nm. The relation between the defect size and the milling time has been established. We confirmed that milling not only occurs on the surface of the spheres, but into and through them as well. We also show that an array of nanocavities can be fashioned. Structurally modified colloids have interesting potential applications in nanolithography, as well as in chemical sensing and solar cells, and as photonic crystal cavities

  5. Transverse emittance measurement of high-current single pulse beams using pepper-pot method

    International Nuclear Information System (INIS)

    Ke Jianlin; Zhou Changgeng; Qiu Rui

    2013-01-01

    A pepper pot-imaging plate system has been developed and used to measure the 4-D transverse emittance of a vacuum arc ion source. Single beam pulses of tens to hundreds milliamperes were extracted from the plasma with 64 kV high voltage. An imaging plate was laid after the pepper pot to visualize the ion beamlets passing though the holes on the pepper pot. An application program was developed to show the phase-space distribution and calculate the ellipse and RMS emittances. The normalized RMS emittances are about 6.41 π·mm·mrad in x-direction and 4.61 π·mm·mrad in y-direction. It is shown that the emittance of the vacuum arc ion source is much larger than that of other types of ion sources, which is mainly attributed to the high current and the convex meniscus of this source. (authors)

  6. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film.

    Science.gov (United States)

    Zhu, Benpeng; Xu, Jiong; Li, Ying; Wang, Tian; Xiong, Ke; Lee, Changyang; Yang, Xiaofei; Shiiba, Michihisa; Takeuchi, Shinichi; Zhou, Qifa; Shung, K Kirk

    2016-03-01

    Single-beam acoustic tweezers (SBAT), used in laboratory-on-a-chip (LOC) device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d 33 = 270pC/N and k t = 0.51) was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9), demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

  7. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film

    Directory of Open Access Journals (Sweden)

    Benpeng Zhu

    2016-03-01

    Full Text Available Single-beam acoustic tweezers (SBAT, used in laboratory-on-a-chip (LOC device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d33 = 270pC/N and kt = 0.51 was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9, demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

  8. Single-particle And Collective Effects Of Cubic Nonlinearity In The Beam Dynamics Of Proton Synchrotrons

    CERN Document Server

    Tran Hy, J

    1998-01-01

    This thesis describes some new studies of the effects of cubic nonlinearities arising from image-charge forces and octupole magnets on the transverse beam dynamics of proton synchrotrons and storage rings, and also a study of the damping of coherent oscillations using a feed-back damper. In the latter case, various corrective algorithms were modeled using linear one-turn maps. Kicks of fixed amplitude but appropriate sign were shown to provide linear damping and no coherent tune shift, though the rate predicted analytically was somewhat higher than that observed in simulations. This algorithm gave much faster damping (for equal power) than conventional proportional kicks, which damp exponentially. Two single-particle effects of the image-change force were investigated: distortion of the momentum dispersion function and amplitude dependence of the betatron tunes (resulting in tune spread). The former is calculated using transfer maps and the method of undetermined coefficients, the latter by solving the cubic ...

  9. Three-dimensional polarization marked multiple-QR code encryption by optimizing a single vectorial beam

    Science.gov (United States)

    Lin, Chao; Shen, Xueju; Hua, Binbin; Wang, Zhisong

    2015-10-01

    We demonstrate the feasibility of three dimensional (3D) polarization multiplexing by optimizing a single vectorial beam using a multiple-signal window multiple-plane (MSW-MP) phase retrieval algorithm. Original messages represented with multiple quick response (QR) codes are first partitioned into a series of subblocks. Then, each subblock is marked with a specific polarization state and randomly distributed in 3D space with both longitudinal and transversal adjustable freedoms. A generalized 3D polarization mapping protocol is established to generate a 3D polarization key. Finally, multiple-QR code is encrypted into one phase only mask and one polarization only mask based on the modified Gerchberg-Saxton (GS) algorithm. We take the polarization mask as the cyphertext and the phase only mask as additional dimension of key. Only when both the phase key and 3D polarization key are correct, original messages can be recovered. We verify our proposal with both simulation and experiment evidences.

  10. Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Benpeng, E-mail: benpengzhu@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Xu, Jiong; Yang, Xiaofei [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Ying; Lee, Changyang; Zhou, Qifa; Shung, K. Kirk [Department of Biomedical Engineering and NIH Transducer Resource Center, University of Southern California, Los Angeles, California 90089-1111 (United States); Wang, Tian; Xiong, Ke [Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan 430072 (China); Shiiba, Michihisa; Takeuchi, Shinichi [Medical Engineering Course, Graduate School of Engineering, Toin University of Yokohama, Yokohama 225-8501 (Japan)

    2016-03-15

    Single-beam acoustic tweezers (SBAT), used in laboratory-on-a-chip (LOC) device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d{sub 33} = 270 pC/N and k{sub t} = 0.51) was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50 MHz, a low f-number (∼0.9), demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

  11. IMPORTANT: Fluke is recalling Digital Clamp Meters

    CERN Multimedia

    2013-01-01

    Fluke is voluntarily recalling four models of Digital Clamp Meters: Fluke 373, 374, 375 and 376. If you own one of these clamp meters, please stop using it and send it back to Fluke for repair even if you have not experienced problems.   Description of the problem: "The printed circuit assembly may not be properly fastened to the test lead input jack. This may result in inaccurate voltage readings, including a low or no-voltage reading on a circuit energised with a hazardous voltage, presenting a shock, electrocution or thermal burn hazard." To determine if your clamp meter is affected by this recall notice, and for more information, click here.

  12. Feasibility of X-ray analysis of multi-layer thin films at a single beam voltage

    International Nuclear Information System (INIS)

    Statham, P J

    2010-01-01

    Multi-layer analysis using electron beam excitation and X-ray spectrometry is a powerful tool for characterising layers down to 1 nm thickness and with typically 1 μm lateral resolution but does not always work. Most published applications have used WDS with many measurements at different beam voltages and considerable experience has been needed to choose lines and voltages particularly for complex multi-layer problems. A new objective mathematical approach is described which demonstrates whether X-ray analysis can obtain reliable results for an arbitrary multi-layer problem. A new algorithm embodied in 'ThinFilmID' software produces a single plot that shows feasibility of achieving results with a single EDS spectrum and suggests the optimal beam voltage. Synthesis of EDS spectra allows the precision in results to be estimated and acquisition conditions modified before wasting valuable instrument time. Thus, practicality of multi-layer thin film analysis at a single beam voltage can now be established without the extensive experimentation that was previously required by a microanalysis expert. Examples are shown where the algorithm discovers viable single-voltage conditions for applications that experts previously thought could only be addressed using measurements at more than one beam voltage.

  13. Tuning permanent magnets with adjustable field clamps

    International Nuclear Information System (INIS)

    Schermer, R.I.

    1987-01-01

    The effective length of a permanent-magnet assembly can be varied by adjusting the geometrical parameters of a field clamp. This paper presents measurements on a representative dipole and quadrupole as the field clamp is withdrawn axially or radially. The detailed behavior depends upon the magnet multipolarity and geometry. As a rule-of-thumb, a 3-mm-thick iron plate placed at one end plane of the magnet will shorten the length by one-third of the magnet bore radius

  14. Single-bunch beam loading on the SLAC two-mile accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.

    1976-01-01

    The experiments described were initially prompted by interest in the radiation loss of relativistic electron rings passing through periodic structures. Later, the same experiments became relevant to the theory of energy loss of electrons in large storage rings. In both of these cases, energy loss to the higher order modes of the respective structures could seriously limit their effective operation as acceleration devices. In these experiments, single bunches of electrons with intensities up to 7 x 10 8 electrons per bunch are accelerated through the SLAC three-kilometer accelerator, and their energy spectra are analyzed. Early experiments over a wide energy range (900 MeV to 19 GeV) demonstrated that the energy loss was proportional to the total charge in the bunch but was independent of beam energy. The average energy loss of a single bunch normalized to 10 9 electrons was initially measured to be 38 MeV. The experiments, including much of the equipment development, are described and are compared with theoretical predictions made to date

  15. A fully three-dimensional reconstruction algorithm with the nonstationary filter for improved single-orbit cone beam SPECT

    International Nuclear Information System (INIS)

    Cao, Z.J.; Tsui, B.M.

    1993-01-01

    Conventional single-orbit cone beam tomography presents special problems. They include incomplete sampling and inadequate three-dimensional (3D) reconstruction algorithm. The commonly used Feldkamp reconstruction algorithm simply extends the two-dimensional (2D) fan beam algorithm to 3D cone beam geometry. A truly 3D reconstruction formulation has been derived for the single-orbit cone beam SPECT based on the 3D Fourier slice theorem. In the formulation, a nonstationary filter which depends on the distance from the central plane of the cone beam was derived. The filter is applied to the 2D projection data in directions along and normal to the axis-of-rotation. The 3D reconstruction algorithm with the nonstationary filter was evaluated using both computer simulation and experimental measurements. Significant improvement in image quality was demonstrated in terms of decreased artifacts and distortions in cone beam reconstructed images. However, compared with the Feldkamp algorithm, a five-fold increase in processing time is required. Further improvement in image quality needs complete sampling in frequency space

  16. Clamp and Gas Nozzle for TIG Welding

    Science.gov (United States)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  17. Planar patch clamp: advances in electrophysiology.

    Science.gov (United States)

    Brüggemann, Andrea; Farre, Cecilia; Haarmann, Claudia; Haythornthwaite, Ali; Kreir, Mohamed; Stoelzle, Sonja; George, Michael; Fertig, Niels

    2008-01-01

    Ion channels have gained increased interest as therapeutic targets over recent years, since a growing number of human and animal diseases have been attributed to defects in ion channel function. Potassium channels are the largest and most diverse family of ion channels. Pharmaceutical agents such as Glibenclamide, an inhibitor of K(ATP) channel activity which promotes insulin release, have been successfully sold on the market for many years. So far, only a small group of the known ion channels have been addressed as potential drug targets. The functional testing of drugs on these ion channels has always been the bottleneck in the development of these types of pharmaceutical compounds.New generations of automated patch clamp screening platforms allow a higher throughput for drug testing and widen this bottleneck. Due to their planar chip design not only is a higher throughput achieved, but new applications have also become possible. One of the advantages of planar patch clamp is the possibility of perfusing the intracellular side of the membrane during a patch clamp experiment in the whole-cell configuration. Furthermore, the extracellular membrane remains accessible for compound application during the experiment.Internal perfusion can be used not only for patch clamp experiments with cell membranes, but also for those with artificial lipid bilayers. In this chapter we describe how internal perfusion can be applied to potassium channels expressed in Jurkat cells, and to Gramicidin channels reconstituted in a lipid bilayer.

  18. Advanced single-slice rebinning for tilted spiral cone-beam CT

    International Nuclear Information System (INIS)

    Kachelriess, Marc; Fuchs, Theo; Schaller, Stefan; Kalender, Willi A.

    2001-01-01

    Future medical CT scanners and today's micro CT scanners demand cone-beam reconstruction algorithms that are capable of reconstructing data acquired from a tilted spiral trajectory where the vector of rotation is not necessarily parallel to the vector of table increment. For the medical CT scanner this case of nonparallel object motion is met for nonzero gantry tilt: the table moves into a direction that is not perpendicular to the plane of rotation. Since this is not a special application of medical CT but rather a daily routine in head exams, there is a strong need for corresponding reconstruction algorithms. In contrast to medical CT, where the special case of nonperpendicular motion is used on purpose, micro CT scanners cannot avoid aberrations of the rotational axis and the table increment vector due to alignment problems. Especially for those micro CT scanners that have the lifting stage mounted on the rotation table (in contrast to setups where the lifting stage holds the rotation table), this kind of misalignment is equivalent to a gantry tilt. We therefore generalize the advanced single-slice rebinning algorithm (ASSR), which is considered a very promising approach for medical cone-beam reconstruction due to its high image quality and its high reconstruction speed [Med. Phys. 27, 754-772 (2000)], to the case of tilted gantries. We evaluate this extended ASSR approach (which we will denote as ASSR + , for convenience) in comparison to the original ASSR algorithm using simulated phantom data for reconstruction. For the case of nonparallel object motion ASSR + shows significant improvements over ASSR, however, its computational complexity is slightly increased due to the broken symmetry of the spiral trajectory

  19. The Role of Geometrically Necessary Dislocations in Cantilever Beam Bending Experiments of Single Crystals

    Directory of Open Access Journals (Sweden)

    Edgar Husser

    2017-03-01

    Full Text Available The mechanical behavior of single crystalline, micro-sized copper is investigated in the context of cantilever beam bending experiments. Particular focus is on the role of geometrically necessary dislocations (GNDs during bending-dominated load conditions and their impact on the characteristic bending size effect. Three different sample sizes are considered in this work with main variation in thickness. A gradient extended crystal plasticity model is presented and applied in a three-dimensional finite-element (FE framework considering slip system-based edge and screw components of the dislocation density vector. The underlying mathematical model contains non-standard evolution equations for GNDs, crystal-specific interaction relations, and higher-order boundary conditions. Moreover, two element formulations are examined and compared with respect to size-independent as well as size-dependent bending behavior. The first formulation is based on a linear interpolation of the displacement and the GND density field together with a full integration scheme whereas the second is based on a mixed interpolation scheme. While the GND density fields are treated equivalently, the displacement field is interpolated quadratically in combination with a reduced integration scheme. Computational results indicate that GND storage in small cantilever beams strongly influences the evolution of statistically stored dislocations (SSDs and, hence, the distribution of the total dislocation density. As a particular example, the mechanical bending behavior in the case of a physically motivated limitation of GND storage is studied. The resulting impact on the mechanical bending response as well as on the predicted size effect is analyzed. Obtained results are discussed and related to experimental findings from the literature.

  20. Systematic study of radiation hardness of single crystal CVD diamond material investigated with an Au beam and IBIC method

    Energy Technology Data Exchange (ETDEWEB)

    Pietraszko, Jerzy; Koenig, Wolfgang; Traeger, Michael [GSI, Darmstadt (Germany); Draveny, Antoine; Galatyuk, Tetyana [TU, Darmstadt (Germany); Grilj, Veljko [RBI, Zagreb (Croatia); Collaboration: HADES-Collaboration

    2016-07-01

    For the future high rate CBM experiment at FAIR a radiation hard and fast beam detector is required. The detector has to perform precise T0 measurement (σ<50 ps) and should also offer decent beam monitoring capability. These tasks can be performed by utilizing single-crystal Chemical Vapor Deposition (ScCVD) diamond based detector. A prototype, segmented, detector have been constructed and the properties of this detector have been studied with a high current density beam (about 3.10{sup 6}/s/mm{sup 2}) of 1.23 A GeV Au ions in HADES. The irradiated detector properties have been studied at RBI in Zagreb by means of IBIC method. Details of the design, the intrinsic properties of the detectors and their performance after irradiation with such beam are reported.

  1. Observation of coherent Smith-Purcell and transition radiation driven by single bunch and micro-bunched electron beams

    Science.gov (United States)

    Liang, Yifan; Du, Yingchao; Su, Xiaolu; Wang, Dan; Yan, Lixin; Tian, Qili; Zhou, Zheng; Wang, Dong; Huang, Wenhui; Gai, Wei; Tang, Chuanxiang; Konoplev, I. V.; Zhang, H.; Doucas, G.

    2018-01-01

    Generation of coherent Smith-Purcell (cSPr) and transition/diffraction radiation using a single bunch or a pre-modulated relativistic electron beam is one of the growing research areas aiming at the development of radiation sources and beam diagnostics for accelerators. We report the results of comparative experimental studies of terahertz radiation generation by an electron bunch and micro-bunched electron beams and the spectral properties of the coherent transition and SP radiation. The properties of cSPr spectra are investigated and discussed, and excitations of the fundamental and second harmonics of cSPr and their dependence on the beam-grating separation are shown. The experimental and theoretical results are compared, and good agreement is demonstrated.

  2. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States); Bender, H. A.; Wilcox, N. S. [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

    2010-01-15

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  3. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector.

    Science.gov (United States)

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Bender, H A; Wilcox, N S

    2010-01-01

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  4. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

    International Nuclear Information System (INIS)

    Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S.; Bender, H. A.; Wilcox, N. S.

    2010-01-01

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  5. Proposal of a Self-baking Single-wall Design for the VI Section of the ATLAS Beam Pipe

    CERN Document Server

    Marco Olcese, MO

    2002-01-01

    A single-wall design for the VI section of the ATLAS beam vacuum chamber is presented. This design would allow for a major cost saving with respect to the current double-wall baseline. All the thermal implications and impact on the B-layer mudules are discussed.

  6. Ring resonator-based single-chip 1x8 optical beam forming network in LPCVD waveguide technology

    NARCIS (Netherlands)

    Zhuang, L.; Roeloffzen, C.G.H.; Heideman, Rene; Borreman, A.; Meijerink, Arjan; van Etten, Wim; Koonen, A.M.J.; Leijtens, X.J.M.; van den Boom, H.P.A.; Verdurmen, E.J.M.; Molina Vázquez, J.

    2006-01-01

    Optical ring resonators (ORRs) are good candidates to provide continuously tunable delay in beam forming networks (BFNs) for phased array antenna systems. Delay and splitting/combining elements can be integrated on a single optical chip to form an OBFN. A state-of-the-art 1×8 OBFN chip has been

  7. Single-chip ring resonator-based 1 x 8 optical beam forming network in CMOS-compatible waveguide technology

    NARCIS (Netherlands)

    Zhuang, L.; Roeloffzen, C.G.H.; Heideman, Rene; Borreman, A.; Meijerink, Arjan; van Etten, Wim

    2007-01-01

    Optical ring resonators (ORRs) are good candidates to provide continuously tunable delay in optical beam forming networks (OBFNs) for phased array antenna systems. Delay and splitting/combining elements can be integrated on a single optical chip to form an OBFN. A state-of-the-art ring resonator-

  8. Electrothermally actuated tunable clamped-guided resonant microbeams

    KAUST Repository

    Alcheikh, Nouha

    2017-06-11

    We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide–range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

  9. Electrothermally actuated tunable clamped-guided resonant microbeams

    Science.gov (United States)

    Alcheikh, N.; Hajjaj, A. Z.; Jaber, N.; Younis, M. I.

    2018-01-01

    We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide-range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

  10. A single-beam titration method for the quantification of open-path Fourier transform infrared spectroscopy

    International Nuclear Information System (INIS)

    Sung, Lung-Yu; Lu, Chia-Jung

    2014-01-01

    This study introduced a quantitative method that can be used to measure the concentration of analytes directly from a single-beam spectrum of open-path Fourier Transform Infrared Spectroscopy (OP-FTIR). The peak shapes of the analytes in a single-beam spectrum were gradually canceled (i.e., “titrated”) by dividing an aliquot of a standard transmittance spectrum with a known concentration, and the sum of the squared differential synthetic spectrum was calculated as an indicator for the end point of this titration. The quantity of a standard transmittance spectrum that is needed to reach the end point can be used to calculate the concentrations of the analytes. A NIST traceable gas standard containing six known compounds was used to compare the quantitative accuracy of both this titration method and that of a classic least square (CLS) using a closed-cell FTIR spectrum. The continuous FTIR analysis of industrial exhausting stack showed that concentration trends were consistent between the CLS and titration methods. The titration method allowed the quantification to be performed without the need of a clean single-beam background spectrum, which was beneficial for the field measurement of OP-FTIR. Persistent constituents of the atmosphere, such as NH 3 , CH 4 and CO, were successfully quantified using the single-beam titration method with OP-FTIR data that is normally inaccurate when using the CLS method due to the lack of a suitable background spectrum. Also, the synthetic spectrum at the titration end point contained virtually no peaks of analytes, but it did contain the remaining information needed to provide an alternative means of obtaining an ideal single-beam background for OP-FTIR. - Highlights: • Establish single beam titration quantification method for OP-FTIR. • Define the indicator for the end-point of spectrum titration. • An ideal background spectrum can be obtained using single beam titration. • Compare the quantification between titration

  11. Beam Normal Single Spin Asymmetry in Forward Angle Inelastic Electron-Proton Scattering using the Q-Weak Apparatus

    Energy Technology Data Exchange (ETDEWEB)

    ., Nuruzzaman [Hampton Univ., Hampton, VA (United States)

    2014-12-01

    The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system

  12. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Berra, A., E-mail: alessandro.berra@gmail.it [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ferri, A. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Novati, C. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ostinelli, A. [Ospedale Sant' Anna, Servizio di Fisica Sanitaria (Italy); Paternoster, G.; Piemonte, C. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Prest, M. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Vallazza, E. [INFN Sezione di Trieste (Italy)

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a “one-shot” device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  13. Geometry modeling of single track cladding deposited by high power diode laser with rectangular beam spot

    Science.gov (United States)

    Liu, Huaming; Qin, Xunpeng; Huang, Song; Hu, Zeqi; Ni, Mao

    2018-01-01

    This paper presents an investigation on the relationship between the process parameters and geometrical characteristics of the sectional profile for the single track cladding (STC) deposited by High Power Diode Laser (HPDL) with rectangle beam spot (RBS). To obtain the geometry parameters, namely cladding width Wc and height Hc of the sectional profile, a full factorial design (FFD) of experiment was used to conduct the experiments with a total of 27. The pre-placed powder technique has been employed during laser cladding. The influence of the process parameters including laser power, powder thickness and scanning speed on the Wc and Hc was analyzed in detail. A nonlinear fitting model was used to fit the relationship between the process parameters and geometry parameters. And a circular arc was adopted to describe the geometry profile of the cross-section of STC. The above models were confirmed by all the experiments. The results indicated that the geometrical characteristics of the sectional profile of STC can be described as the circular arc, and the other geometry parameters of the sectional profile can be calculated only using Wc and Hc. Meanwhile, the Wc and Hc can be predicted through the process parameters.

  14. A robust single-beam optical trap for a gram-scale mechanical oscillator.

    Science.gov (United States)

    Altin, P A; Nguyen, T T-H; Slagmolen, B J J; Ward, R L; Shaddock, D A; McClelland, D E

    2017-11-06

    Precise optical control of microscopic particles has been mastered over the past three decades, with atoms, molecules and nano-particles now routinely trapped and cooled with extraordinary precision, enabling rapid progress in the study of quantum phenomena. Achieving the same level of control over macroscopic objects is expected to bring further advances in precision measurement, quantum information processing and fundamental tests of quantum mechanics. However, cavity optomechanical systems dominated by radiation pressure - so-called 'optical springs' - are inherently unstable due to the delayed dynamical response of the cavity. Here we demonstrate a fully stable, single-beam optical trap for a gram-scale mechanical oscillator. The interaction of radiation pressure with thermo-optic feedback generates damping that exceeds the mechanical loss by four orders of magnitude. The stability of the resultant spring is robust to changes in laser power and detuning, and allows purely passive self-locking of the cavity. Our results open up a new way of trapping and cooling macroscopic objects for optomechanical experiments.

  15. Simultaneous 3D-vibration measurement using a single laser beam device

    Science.gov (United States)

    Brecher, Christian; Guralnik, Alexander; Baümler, Stephan

    2012-06-01

    Today's commercial solutions for vibration measurement and modal analysis are 3D-scanning laser doppler vibrometers, mainly used for open surfaces in the automotive and aerospace industries and the classic three-axial accelerometers in civil engineering, for most industrial applications in manufacturing environments, and particularly for partially closed structures. This paper presents a novel measurement approach using a single laser beam device and optical reflectors to simultaneously perform 3D-dynamic measurement as well as geometry measurement of the investigated object. We show the application of this so called laser tracker for modal testing of structures on a mechanical manufacturing shop floor. A holistic measurement method is developed containing manual reflector placement, semi-automated geometric modeling of investigated objects and fully automated vibration measurement up to 1000 Hz and down to few microns amplitude. Additionally the fast set up dynamic measurement of moving objects using a tracking technique is presented that only uses the device's own functionalities and does neither require a predefined moving path of the target nor an electronic synchronization to the moving object.

  16. Single-beam bathymetry data collected in 2015 from Grand Bay, Alabama-Mississippi

    Science.gov (United States)

    DeWitt, Nancy T.; Stalk, Chelsea A.; Smith, Christopher G.; Locker, Stanley D.; Fredericks, Jake J.; McCloskey, Terrence A.; Wheaton, Cathryn J.

    2017-12-01

    As part of the Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a single-beam bathymetry survey within the estuarine, open-bay, and tidal creek environments of Grand Bay, Alabama-Mississippi, from May to June 2015. The goal of the SSIEES project is to assess the physical controls of sediment and material exchange between wetlands and estuarine environments along the northern Gulf of Mexico, specifically Grand Bay, Alabama-Mississippi; Vermilion Bay, Louisiana; and, along the east coast, within Chincoteague Bay, Virginia-Maryland. The data described in this report provide baseline bathymetric information for future research investigating wetland-marsh evolution, sediment transport, erosion, recent and long-term geomorphic change, and can also support the modeling of changes in response to restoration and storm impacts. The survey area encompasses more than 40 square kilometers of Grand Bay’s waters.

  17. Commissioning of the ATLAS high-level trigger with single beam and cosmic rays

    CERN Document Server

    Özcan, V Erkcan

    2010-01-01

    ATLAS is one of the two general-purpose detectors at the Large Hadron Collider (LHC). Using fast reconstruction algorithms, its trigger system needs to efficiently reject a huge rate of background events and still select potentially interesting ones with good efficiency. After a first processing level using custom electronics, the trigger selection is made by software running on two processor farms, designed to have a total of around two thousand multi-core machines. This system is known as the High Level Trigger (HLT). To reduce the network data traffic and the processing time to manageable levels, the HLT uses seeded, step-wise reconstruction, aiming at the earliest possible rejection of background events. The recent LHC startup and short single-beam run provided a "stress test" of the trigger. Following this period, ATLAS continued to collect cosmic-ray events for detector alignment and calibration purposes. These running periods allowed strict tests of the HLT reconstruction and selection algorithms as we...

  18. Pipe clamp effects on thin-walled pipe design

    International Nuclear Information System (INIS)

    Lindquist, M.R.

    1980-01-01

    Clamp induced stresses in FFTF piping are sufficiently large to require structural assessment. The basic principles and procedures used in analyzing FFTF piping at clamp support locations for compliance with ASME Code rules are given. Typical results from a three-dimensional shell finite element pipe model with clamp loads applied over the clamp/pipe contact area are shown. Analyses performed to categorize clamp induced piping loads as primary or secondary in nature are described. The ELCLAMP Computer Code, which performs analyses at clamp locations combining clamp induced stresses with stresses from overall piping system loads, is discussed. Grouping and enveloping methods to reduce the number of individual clamp locations requiring analysis are described

  19. Use of the Satinsky clamp for hilar clamping during robotic partial nephrectomy: indications, technique, and multi-center outcomes.

    Science.gov (United States)

    Abdullah, Newaj; Rahbar, Haider; Barod, Ravi; Dalela, Deepansh; Larson, Jeff; Johnson, Michael; Mass, Alon; Zargar, Homayoun; Kaouk, Jihad; Allaf, Mohamad; Bhayani, Sam; Stifelman, Michael; Rogers, Craig

    2017-03-01

    A Satinsky clamp may be a backup option for hilar clamping during robotic partial nephrectomy (RPN) if there are challenges with application of bulldog clamps, but there are potential safety concerns. We evaluate outcomes of RPN using Satinsky vs. bulldog clamps, and provide tips for safe use of the Satinsky as a backup option. Using a multi-center database, we identified 1073 patients who underwent RPN between 2006 and 2013, and had information available about method of hilar clamping (bulldog clamp vs. Satinsky clamp). Patient baseline characteristics, tumor features, and perioperative outcomes were compared between the Satinsky and bulldog clamp groups. A Satinsky clamp was used for hilar clamping in 94 (8.8 %) RPN cases, and bulldog clamps were used in 979 (91.2 %) cases. The use of a Satinsky clamp was associated with greater operative time (198 vs. 175 min, p hilar clamping during challenging RPN cases, but requires careful technique, and was rarely necessary.

  20. Implementation of single-breath-hold cone beam CT guided hypofraction radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Zhong, Renming; Lu, You; Wang, Jin; Zhou, Lin; Xu, Feng; Liu, Li; Zhou, Jidan; Jiang, Xiaoqin; Chen, Nianyong; Bai, Sen

    2014-01-01

    To analyze the feasibility of active breath control (ABC), the lung tumor reproducibility and the rationale for single-breath-hold cone beam CT (CBCT)-guided hypofraction radiotherapy. Single-breath-hold CBCT images were acquired using ABC in a cohort of 83 lung cancer patients (95 tumors) treated with hypofraction radiotherapy. For all alignments between the reference CT and CBCT images (including the pre-correction, post-correction and post-treatment CBCT images), the tumor reproducibility was evaluated via online manual alignment of the tumors, and the vertebral bone uncertainties were evaluated via offline manual alignment of the vertebral bones. The difference between the tumor reproducibility and the vertebral bone uncertainty represents the change in the tumor position relative to the vertebral bone. The relative tumor positions along the coronal, sagittal and transverse axes were measured based on the reference CT image. The correlations between the vertebral bone uncertainty, the relative tumor position, the total treatment time and the tumor reproducibility were evaluated using the Pearson correlations. Pre-correction, the systematic/random errors of tumor reproducibility were 4.5/2.6 (medial-lateral, ML), 5.1/4.8 (cranial-caudal, CC) and 4.0/3.6 mm (anterior-posterior, AP). These errors were significantly decreased to within 3 mm, both post-correction and post-treatment. The corresponding PTV margins were 4.7 (ML), 7.4 (CC) and 5.4 (AP) mm. The changes in the tumor position relative to the vertebral bone displayed systematic/random errors of 2.2/2.0 (ML), 4.1/4.4 (CC) and 3.1/3.3 (AP) mm. The uncertainty of the vertebral bone significantly correlated to the reproducibility of the tumor position (P < 0.05), except in the CC direction post-treatment. However, no significant correlation was detected between the relative tumor position, the total treatment time and the tumor reproducibility (P > 0.05). Using ABC for single-breath-hold CBCT guidance is an

  1. Synthesizing single-phase β-FeSi2 via ion beam irradiations of Fe/Si bilayers

    International Nuclear Information System (INIS)

    Milosavljevic, M.; Dhar, S.; Schaaf, P.; Bibic, N.; Lieb, K.P.

    2001-01-01

    This paper presents results on the direct synthesis of the β-FeSi 2 phase by ion beam mixing of Fe/Si bilayers with Xe ions. The influence of the substrate temperature, ion fluence and energy on the growth of this phase was investigated using Rutherford backscattering (RBS), X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS). Complete growth of single-phase β-FeSi 2 was achieved by 205 keV Xe ion irradiation to a fluence of 2x10 16 ions/cm 2 at 600 deg. C. We propose a two-step reaction mechanism involving thermal and ion beam energy deposition

  2. Direct generation of an optical vortex beam in a single-frequency Nd:YVO4 laser.

    Science.gov (United States)

    Kim, D J; Kim, J W

    2015-02-01

    A simple method for generating a Laguerre-Gaussian (LG) mode optical vortex beam with well-determined handedness in a single-frequency solid state laser end-pumped by a ring-shaped pump beam is reported. After investigating the intensity profile and the wavefront helicity of each longitudinal mode output to understand generation of the LG mode in a Nd:YVO4 laser resonator, selection of the wavefront handedness has been achieved simply by inserting and tilting an etalon in the resonator, which breaks the propagation symmetry of the Poynting vectors with opposite helicity. Simple calculation and the experimental results are discussed for supporting this selection mechanism.

  3. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  4. Development of a synthetic single crystal diamond dosimeter for dose measurement of clinical proton beams

    Science.gov (United States)

    Moignier, Cyril; Tromson, Dominique; de Marzi, Ludovic; Marsolat, Fanny; García Hernández, Juan Carlos; Agelou, Mathieu; Pomorski, Michal; Woo, Romuald; Bourbotte, Jean-Michel; Moignau, Fabien; Lazaro, Delphine; Mazal, Alejandro

    2017-07-01

    The scope of this work was to develop a synthetic single crystal diamond dosimeter (SCDD-Pro) for accurate relative dose measurements of clinical proton beams in water. Monte Carlo simulations were carried out based on the MCNPX code in order to investigate and reduce the dose curve perturbation caused by the SCDD-Pro. In particular, various diamond thicknesses were simulated to evaluate the influence of the active volume thickness (e AV) as well as the influence of the addition of a front silver resin (250 µm in thickness in front of the diamond crystal) on depth-dose curves. The simulations indicated that the diamond crystal alone, with a small e AV of just 5 µm, already affects the dose at Bragg peak position (Bragg peak dose) by more than 2% with respect to the Bragg peak dose deposited in water. The optimal design that resulted from the Monte Carlo simulations consists of a diamond crystal of 1 mm in width and 150 µm in thickness with the front silver resin, enclosed by a water-equivalent packaging. This design leads to a deviation between the Bragg peak dose from the full detector modeling and the Bragg peak dose deposited in water of less than 1.2%. Based on those optimizations, an SCDD-Pro prototype was built and evaluated in broad passive scattering proton beams. The experimental evaluation led to probed SCDD-Pro repeatability, dose rate dependence and linearity, that were better than 0.2%, 0.4% (in the 1.0-5.5 Gy min-1 range) and 0.4% (for dose higher than 0.05 Gy), respectively. The depth-dose curves in the 90-160 MeV energy range, measured with the SCDD-Pro without applying any correction, were in good agreement with those measured using a commercial IBA PPC05 plane-parallel ionization chamber, differing by less than 1.6%. The experimental results confirmed that this SCDD-Pro is suitable for measurements with standard electrometers and that the depth-dose curve perturbation is negligible, with no energy dependence and no significant dose rate

  5. Analysis of the Pallet Clamping Conditions in Work Positioning

    Directory of Open Access Journals (Sweden)

    L. A. Kolesnikov

    2016-01-01

    Full Text Available Pallets of automatic transfer lines serve as the technological and work-transfer equipment. However, their design is based on the general principles of designing machine accessories. Calculation of the basic design parameters of work based on their functioning features is fairly relevant.In pallet transfer movement over work positioning there is a mismatch between axes of the basic bushing of a pallet and the clamping locks of positioning. The paper identifies the factors influencing it, and defines the conditions to ensure the trouble-free clamping lock. The circular and rhombic clamping of pallet is simultaneous. Further, a clamping load is calculated from the pallet mass (together with the work-piece and the geometric parameters of the pallet clamping.The paper reveals three movement stages of the clamping lock in a vertical plane when setting the pallet in work positioning:- a clamping lock free play till it encounters with the location bushing;- a clamping lock play length when the lead-in chamfer contacts the bushing chamfer;- a clamping lock play length over the circular surface of bushing.The study of this process has allowed us to calculate the time of pallet clamping and dynamic loads acting on the clamping lock. These calculations made it possible to calculate the required diameter of the clamping lock. The presented calculations allow a reasonable assigning the main design parameters of work positioning for the pallet automatic lines.

  6. Beam separation for p-anti p collisions in a single ring in the multibunch mode

    International Nuclear Information System (INIS)

    Berley, D.; Garren, A.A.; Month, M.

    1978-01-01

    A discussion is given of proton-antiproton colliding beam operation in storage rings. Some means of separating the beams at points where no experiment is being performed seems to be an important feature for a p-anti p colliding beam ring. By exciting a betatron oscillation in some appropriate, localized region, one could create a specific collision point while at the same time cause the p and anti p beams to oscillate in opposition so that their orbits meet at only a small number of points, roughly given by twice the tune, 2ν

  7. π-Clamp-mediated cysteine conjugation

    Science.gov (United States)

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; van Voorhis, Troy; Pentelute, Bradley L.

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the ‘π-clamp’, that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  8. On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

    KAUST Repository

    Jaber, Nizar; Masri, Karim M.; Younis, Mohammad I.

    2017-01-01

    This work aims to investigate theoretically and experimentally various nonlinear dynamic behaviors of a doubly clamped microbeam near its primary resonance. Mainly, we investigate the transition behavior from hardening, mixed, and then softening behavior. We show in a single frequency-response curve, under a constant voltage load, the transition from hardening to softening behavior demonstrating the dominance of the quadratic electrostatic nonlinearity over the cubic geometric nonlinearity of the beam as the motion amplitudes becomes large, which may lead eventually to dynamic pull-in. The microbeam is fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from the bottom. Frequency sweep tests are conducted for different values of DC bias revealing hardening, mixed, and softening behavior of the microbeam. A multi-mode Galerkin model combined with a shooting technique are implemented to generate the frequency response curves and to analyze the stability of the periodic motions using the Floquet theory. The simulated curves show good agreement with the experimental data.

  9. On the Nonlinear Dynamics of a Doubly Clamped Microbeam near Primary Resonance

    KAUST Repository

    Jaber, Nizar

    2017-04-07

    This work aims to investigate theoretically and experimentally various nonlinear dynamic behaviors of a doubly clamped microbeam near its primary resonance. Mainly, we investigate the transition behavior from hardening, mixed, and then softening behavior. We show in a single frequency-response curve, under a constant voltage load, the transition from hardening to softening behavior demonstrating the dominance of the quadratic electrostatic nonlinearity over the cubic geometric nonlinearity of the beam as the motion amplitudes becomes large, which may lead eventually to dynamic pull-in. The microbeam is fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from the bottom. Frequency sweep tests are conducted for different values of DC bias revealing hardening, mixed, and softening behavior of the microbeam. A multi-mode Galerkin model combined with a shooting technique are implemented to generate the frequency response curves and to analyze the stability of the periodic motions using the Floquet theory. The simulated curves show good agreement with the experimental data.

  10. Clamping-induced changes of domain morphology in 88%Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-12%PbTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chang, L.-W., E-mail: lchang01@qub.ac.uk; Gregg, J. M., E-mail: m.gregg@qub.ac.uk [Centre for Nanostructured Media, School of Maths and Physics, Queen' s University Belfast, Northern Ireland BT7 1NN (United Kingdom); Nagarajan, V.; Okatan, M. B. [School of Materials Science and Engineering, University of New South Wales, New South Wales 2052 (Australia)

    2014-08-14

    Domain microstructures in single crystal lamellae of 88%Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-12%PbTiO{sub 3} (cut from bulk using focused ion beam milling) have been mapped using both piezoresponse force microscopy and transmission electron microscopy. Dramatic changes from mottled microstructures typical of relaxors to larger scale domains typical of ferroelectrics have been noted. Stresses associated with substrate clamping are suspected as the cause for the transition from short- to long-range polar order, akin to effects induced by cation ordering achieved by thermal quenching.

  11. Bunch-shape monitor for a picosecond single-bunch beam of a 35 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Hosono, Yoneichi; Nakazawa, Masaharu; Iguchi, Tetsuo

    1995-01-01

    A non-interactive-type bunch-shape and beam intensity monitor for a 35 MeV electron linear accelerator (linac) has been developed. The monitor consists of an electric SMA-type connector and an Al pipe of 50 mm inner diameter. Test measurements of the present monitor have been made under the conditions of the accelerated charges of lower than 27 nC/pulse and the pulse width ranging from 6 to 30 ps (Full Width at Half Maximum). The results show that the present monitor is applicable to bunch-shape measurement of the picosecond single-bunch beam. The monitor output is also found to be proportional to the beam intensity of more than 0.05 nC/pulse. (author)

  12. Single-jet gas cooling of in-beam foils or specimens: Prediction of the convective heat-transfer coefficient

    Science.gov (United States)

    Steyn, Gideon; Vermeulen, Christiaan

    2018-05-01

    An experiment was designed to study the effect of the jet direction on convective heat-transfer coefficients in single-jet gas cooling of a small heated surface, such as typically induced by an accelerated ion beam on a thin foil or specimen. The hot spot was provided using a small electrically heated plate. Heat-transfer calculations were performed using simple empirical methods based on dimensional analysis as well as by means of an advanced computational fluid dynamics (CFD) code. The results provide an explanation for the observed turbulent cooling of a double-foil, Havar beam window with fast-flowing helium, located on a target station for radionuclide production with a 66 MeV proton beam at a cyclotron facility.

  13. Limit load solution for electron beam welded joints with single edge weld center crack in tension

    Science.gov (United States)

    Lu, Wei; Shi, Yaowu; Li, Xiaoyan; Lei, Yongping

    2012-05-01

    Limit loads are widely studied and several limit load solutions are proposed to some typical geometry of weldments. However, there are no limit load solutions exist for the single edge crack weldments in tension (SEC(T)), which is also a typical geometry in fracture analysis. The mis-matching limit load for thick plate with SEC(T) are investigated and the special limit load solutions are proposed based on the available mis-matching limit load solutions and systematic finite element analyses. The real weld configurations are simplified as a strip, and different weld strength mis-matching ratio M, crack depth/width ratio a/ W and weld width 2H are in consideration. As a result, it is found that there exists excellent agreement between the limit load solutions and the FE results for almost all the mis-matching ration M, a/ W and ligament-to-weld width ratio ( W-a)/ H. Moreover, useful recommendations are given for evaluating the limit loads of the EBW structure with SEC(T). For the EBW joints with SEC(T), the mis-matching limit loads can be obtained assuming that the components are wholly made of base metal, when M changing from 1.6 to 0.6. When M decreasing to 0.4, the mis-matching limit loads can be obtained assuming that the components are wholly made of base metal only for large value of ( W-a)/ H. The recommendations may be useful for evaluating the limit loads of the EBW structures with SEC(T). The engineering simplifications are given for assessing the limit loads of electron beam welded structure with SEC(T).

  14. The plastic instability of clamped-clamped conical thin-walled pipe reducers

    International Nuclear Information System (INIS)

    Awad, Ibrahim; Saleh, Ch.A.R.; Ragab, A.R.

    2016-01-01

    The analytical study for plastic deformation of clamped–clamped conical reducer pipe under internal pressure does not deduce a closed form expression for the pressure at plastic instability. The presented study employs finite element analysis (FEA) to estimate the internal pressure at instability for conical reducers made of different materials and having different dimensional configurations. Forty dimensional configurations, classified as medium type, and five types of materials have been included in the analysis using ABAQUS package. A correlation expression is derived by nonlinear regression to predict the instability pressure. The proposed expression is verified for other dimensional configurations out of the above used forty models and for other materials. Experiments have been conducted by pressurizing conical clamped-clamped reducers until bursting in order to verify the finite element models. Comparison of instability pressures, strains and deflections at specific points along the conical surface shows satisfactory agreement between analysis and experiments. - Highlights: • This study offers a parametric study of the plastic instability pressure of clamped-clamped conical reducers. • A closed form analytical expression for the instability pressure is derived by using nonlinear regression. • The finite element analysis is validated by conducting bursting tests.

  15. The number of beams in IMRT-theoretical investigations and implications for single-arc IMRT

    International Nuclear Information System (INIS)

    Bortfeld, Thomas

    2010-01-01

    The first purpose of this paper is to shed some new light on the old question of selecting the number of beams in intensity-modulated radiation therapy (IMRT). The second purpose is to illuminate the related issue of discrete static beam angles versus rotational techniques, which has recently re-surfaced due to the advancement of volumetric modulated arc therapy (VMAT). A specific objective is to find analytical expressions that allow one to address the points raised above. To make the problem mathematically tractable, it is assumed that the depth dose is flat and that the lateral dose profile can be approximated by polynomials, specifically Chebyshev polynomials of the first kind, of finite degree. The application of methods known from image reconstruction then allows one to answer the first question above as follows: the required number of beams is determined by the maximum degree of the polynomials used in the approximation of the beam profiles, which is a measure of the dose variability. There is nothing to be gained by using more beams. In realistic cases, in which the variability of the lateral dose profile is restricted in several ways, the required number of beams is of the order of 10-20. The consequence of delivering the beams with a 'leaf sweep' technique during continuous rotation of the gantry, as in VMAT, is also derived in an analytical form. The main effect is that the beams fan out, but the effect near the axis of rotation is small. This result can serve as a theoretical justification of VMAT. Overall the analytical derivations in this paper, albeit based on strong simplifications, provide new insights into, and a deeper understanding of, the beam angle problem in IMRT. The decomposition of the beam profiles into well-behaved and easily deliverable smooth functions, such as Chebyshev polynomials, could be of general interest in IMRT treatment planning.

  16. The effect of a single blade limiter on energetic neutral beam particles in Doublet III

    International Nuclear Information System (INIS)

    Petrie, T.W.; Armentrout, C.; Burrell, K.H.; Hino, T.; Kahn, C.; Kim, J.; Lohr, J.; Rottler, L.; Schissel, D.; St John, H.

    1984-01-01

    Energetic beam ion collisions with the main limiter can be a significant power loss process under certain operating conditions in Doublet III. Futhermore, these collisions may cause measurable damage to the limiter itself. Under low current and low toroidal field conditions (e.g., Isub(p) = 290 kA and Bsub(T) = 6.3 kG), 20-38% of the inferred absorbed beam power may be deposited directly on the ion drift side of the limiter by the beam ions. However, for higher plasma current and toroidal fields (e.g., Isub(p) = 480 kA and Bsub(t) = 15 kG), the fraction of inferred absorbed beam power deposited on the limiter is reduced to < 10%. Monte Carlo code simulations show that this loss of beam power is primarily a result of the large poloidal and toroidal gyro-orbits of the energetic beam ions. Other factors which may enhance beam ion losses to the limiter are (1) large separation distances between the primary limiter and the (outboard) vacuum vessel wall, and (2) plasma density buildup near the plasma edge during high gas puff operation. In addition, our data suggests enhanced plasma density and recycling near the limiter. This localized density can cause appreciable premature ionizations of the incoming beam neutrals and thus reduce the effective plasma heating of the beamline which is immediately upcurrent of the limiter. The prematurely-ionized beam particles from this adjacent beamline are responsible for much of the damage to the ion drift side of the limiter. We have found that under certain operating conditions (1) the direct beam heating of the limiter is 50% greater and (2) the stored plasma energy is 10% less when the beamline immediately upcurrent of the limiter heats the plasma. Thus, the relative positions of the limiters to the beamlines are important in designing future tokamaks. (orig.)

  17. Single-Fraction Proton Beam Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Hattangadi-Gluth, Jona A. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Chapman, Paul H. [Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts (United States); Kim, Daniel; Niemierko, Andrzej; Bussière, Marc R.; Stringham, Alison; Daartz, Juliane [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Ogilvy, Christopher [Department of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-06-01

    Purpose/Objective(s): To evaluate the obliteration rate and potential adverse effects of single-fraction proton beam stereotactic radiosurgery (PSRS) in patients with cerebral arteriovenous malformations (AVMs). Methods and Materials: From 1991 to 2010, 248 consecutive patients with 254 cerebral AVMs received single-fraction PSRS at our institution. The median AVM nidus volume was 3.5 cc (range, 0.1-28.1 cc), 23% of AVMs were in critical/deep locations (basal ganglia, thalamus, or brainstem), and the most common prescription dose was 15 Gy(relative biological effectiveness [RBE]). Univariable and multivariable analyses were performed to assess factors associated with obliteration and hemorrhage. Results: At a median follow-up time of 35 months (range, 6-198 months), 64.6% of AVMs were obliterated. The median time to total obliteration was 31 months (range, 6-127 months), and the 5-year and 10-year cumulative incidence of total obliteration was 70% and 91%, respectively. On univariable analysis, smaller target volume (hazard ratio [HR] 0.78, 95% confidence interval [CI] 0.86-0.93, P<.0001), smaller treatment volume (HR 0.93, 95% CI 0.90-0.96, P<.0001), higher prescription dose (HR 1.16, 95% CI 1.07-1.26, P=.001), and higher maximum dose (HR 1.14, 95% CI 1.05-1.23, P=.002) were associated with total obliteration. Deep/critical location was also associated with decreased likelihood of obliteration (HR 0.68, 95% CI 0.47-0.98, P=.04). On multivariable analysis, critical location (adjusted HR [AHR] 0.42, 95% CI 0.27-0.65, P<.001) and smaller target volume (AHR 0.81, 95% CI 0.68-0.97, P=.02) remained associated with total obliteration. Posttreatment hemorrhage occurred in 13 cases (5-year cumulative incidence of 7%), all among patients with less than total obliteration, and 3 of these events were fatal. The most common complication was seizure, controlled with medications, both acutely (8%) and in the long term (9.1%). Conclusions: The current series is the largest

  18. Molecular mechanism of DNA replication-coupled inactivation of the initiator protein in Escherichia coli: interaction of DnaA with the sliding clamp-loaded DNA and the sliding clamp-Hda complex.

    Science.gov (United States)

    Su'etsugu, Masayuki; Takata, Makoto; Kubota, Toshio; Matsuda, Yusaku; Katayama, Tsutomu

    2004-06-01

    In Escherichia coli, the ATP-DnaA protein initiates chromosomal replication. After the DNA polymerase III holoenzyme is loaded on to DNA, DnaA-bound ATP is hydrolysed in a manner depending on Hda protein and the DNA-loaded form of the DNA polymerase III sliding clamp subunit, which yields ADP-DnaA, an inactivated form for initiation. This regulatory DnaA-inactivation represses extra initiation events. In this study, in vitro replication intermediates and structured DNA mimicking replicational intermediates were first used to identify structural prerequisites in the process of DnaA-ATP hydrolysis. Unlike duplex DNA loaded with sliding clamps, primer RNA-DNA heteroduplexes loaded with clamps were not associated with DnaA-ATP hydrolysis, and duplex DNA provided in trans did not rescue this defect. At least 40-bp duplex DNA is competent for the DnaA-ATP hydrolysis when a single clamp was loaded. The DnaA-ATP hydrolysis was inhibited when ATP-DnaA was tightly bound to a DnaA box-bearing oligonucleotide. These results imply that the DnaA-ATP hydrolysis involves the direct interaction of ATP-DnaA with duplex DNA flanking the sliding clamp. Furthermore, Hda protein formed a stable complex with the sliding clamp. Based on these, we suggest a mechanical basis in the DnaA-inactivation that ATP-DnaA interacts with the Hda-clamp complex with the aid of DNA binding. Copyright Blackwell Publishing Limited

  19. An evaluation testing technique of single event effect using Beam Blanking SEM

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, J; Hada, T; Pesce, A; Akutsu, T; Matsuda, S [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan). Tsukuba Space Center; Igarashi, T; Baba, S

    1997-03-01

    Beam Blanking SEM (Scanning Electron Microscope) testing technique has been applied to CMOS SRAM devices to evaluate the occurence of soft errors on memory cells. Cross-section versus beam current and LET curves derived from BBSEM and heavy ion testing technique, respectively, have been compared. A linear relation between BBSEM current and heavy ion LET has been found. The purpose of this study was to demonstrate that the application of focused pulsed electron beam could be a reliable, convenient and inexpensive tool to investigate the effects of heavy ions and high energy particles on memory devices for space application. (author)

  20. A simple technique to measure regional cerebral blood flow during intravascular ballon clamping

    International Nuclear Information System (INIS)

    Furuhata, Shigeru; Kubo, Atsushi; Kawase, Takeshi; Ibata, Yukio; Toya, Shigeo

    1988-01-01

    A case of giant internal carotid ophthalmic aneurysm was presented. In order to clarify whether the patient could tolerate carotid occlusion, a ballon clamping test was performed before surgery. The cerebral blood flow was measured using early imaging by single photon emission computed tomography (SPECT) with N-isopropyl-(iodine-123)-p-iodoamphetamine ( 123 I-IMP). When the ballon clamping test was performed the tracer was injected, and scanning was performed 35 minutes after removing the catheter. This tracer enabled a 'memory of blood flow' during temporary ischemia to determine the character of quick diffusion and slow wash out, that could not be performed by other methods of cerebral blood flow measurement. SPECT with 123 I-IMP can simplify the measurement of cerebral blood flow during the balloon clamping test. (author)

  1. Probing the Single-Particle Character of Rotational States in F 19 Using a Short-Lived Isomeric Beam

    Science.gov (United States)

    Santiago-Gonzalez, D.; Auranen, K.; Avila, M. L.; Ayangeakaa, A. D.; Back, B. B.; Bottoni, S.; Carpenter, M. P.; Chen, J.; Deibel, C. M.; Hood, A. A.; Hoffman, C. R.; Janssens, R. V. F.; Jiang, C. L.; Kay, B. P.; Kuvin, S. A.; Lauer, A.; Schiffer, J. P.; Sethi, J.; Talwar, R.; Wiedenhöver, I.; Winkelbauer, J.; Zhu, S.

    2018-03-01

    A beam containing a substantial component of both the Jπ=5+ , T1 /2=162 ns isomeric state of F 18 and its 1+, 109.77-min ground state is utilized to study members of the ground-state rotational band in F 19 through the neutron transfer reaction (d ,p ) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13 /2+ band-terminating state. The agreement between shell-model calculations using an interaction constructed within the s d shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.

  2. Single-shot beam-position monitor for x-ray free electron laser

    Science.gov (United States)

    Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

    2011-02-01

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  3. Three-dimensional single-photon emission computed tomography using cone beam collimation (CB-SPECT)

    International Nuclear Information System (INIS)

    Jaszczak, R.J.; Floyd, C.E. Jr.; Manglos, S.H.; Greer, K.L.; Coleman, R.E.

    1986-01-01

    A simple and economically practical method of improving the sensitivity of camera-based SPECT was developed using converging (cone-beam) collimation. This geometry is particularly advantageous for SPECT devices using large field-of-view cameras in imaging smaller, centrally located activity distributions. Geometric sensitivities, spatial resolutions, and fields-of-view of a cone-beam collimator having a focal length of 48 cm and a similarly designed parallel hole collimator were compared analytically. At 15 cm from the collimator surface the point-source sensitivity of the cone-beam collimator was 2.4 times the sensitivity of the parallel-hole collimator. SPECT projection data (simulated using Monte Carlo methodology) were reconstructed using a 3-D filtered backprojection algorithm. Cone-beam emission CT (CB-SPECT) seems potentially useful for animal investigations, pediatric studies, and for brain imaging

  4. Velocity Spread Reduction for Axis-encircling Electron Beam Generated by Single Magnetic Cusp

    Science.gov (United States)

    Jeon, S. G.; Baik, C. W.; Kim, D. H.; Park, G. S.; Sato, N.; Yokoo, K.

    2001-10-01

    Physical characteristics of an annular Pierce-type electron gun are investigated analytically. An annular electron gun is used in conjunction with a non-adiabatic magnetic reversal and an adiabatic compression to produce an axis-encircling electron beam. Velocity spread close to zero is realized with an initial canonical angular momentum spread at the cathode when the beam trajectory does not coincide with the magnetic flux line. Both the analytical calculation and the EGUN code simulation confirm this phenomenon.

  5. Protein associations in DnaA-ATP hydrolysis mediated by the Hda-replicase clamp complex.

    Science.gov (United States)

    Su'etsugu, Masayuki; Shimuta, Toh-Ru; Ishida, Takuma; Kawakami, Hironori; Katayama, Tsutomu

    2005-02-25

    In Escherichia coli, the activity of ATP-bound DnaA protein in initiating chromosomal replication is negatively controlled in a replication-coordinated manner. The RIDA (regulatory inactivation of DnaA) system promotes DnaA-ATP hydrolysis to produce the inactivated form DnaA-ADP in a manner depending on the Hda protein and the DNA-loaded form of the beta-sliding clamp, a subunit of the replicase holoenzyme. A highly functional form of Hda was purified and shown to form a homodimer in solution, and two Hda dimers were found to associate with a single clamp molecule. Purified mutant Hda proteins were used in a staged in vitro RIDA system followed by a pull-down assay to show that Hda-clamp binding is a prerequisite for DnaA-ATP hydrolysis and that binding is mediated by an Hda N-terminal motif. Arg(168) in the AAA(+) Box VII motif of Hda plays a role in stable homodimer formation and in DnaA-ATP hydrolysis, but not in clamp binding. Furthermore, the DnaA N-terminal domain is required for the functional interaction of DnaA with the Hda-clamp complex. Single cells contain approximately 50 Hda dimers, consistent with the results of in vitro experiments. These findings and the features of AAA(+) proteins, including DnaA, suggest the following model. DnaA-ATP is hydrolyzed at a binding interface between the AAA(+) domains of DnaA and Hda; the DnaA N-terminal domain supports this interaction; and the interaction of DnaA-ATP with the Hda-clamp complex occurs in a catalytic mode.

  6. Biological cell controllable patch-clamp microchip

    Science.gov (United States)

    Penmetsa, Siva; Nagrajan, Krithika; Gong, Zhongcheng; Mills, David; Que, Long

    2010-12-01

    A patch-clamp (PC) microchip with cell sorting and positioning functions is reported, which can avoid drawbacks of random cell selection or positioning for a PC microchip. The cell sorting and positioning are enabled by air bubble (AB) actuators. AB actuators are pneumatic actuators, in which air pressure is generated by microheaters within sealed microchambers. The sorting, positioning, and capturing of 3T3 cells by this type of microchip have been demonstrated. Using human breast cancer cells MDA-MB-231 as the model, experiments have been demonstrated by this microchip as a label-free technical platform for real-time monitoring of the cell viability.

  7. Bingham Sealing and Application in Vacuum Clamping

    Science.gov (United States)

    Yao, S. M.; Teo, Wee Kin; Geng, Zunmin; Turner, Sam; Ridgway, Keith

    2011-12-01

    Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of "O"ring sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with "O" ring sealing.

  8. Bingham Sealing and Application in Vacuum Clamping

    International Nuclear Information System (INIS)

    Yao, S M; Teo, Wee Kin; Geng Zunmin; Turner, Sam; Ridgway, Keith

    2011-01-01

    Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of Or ing sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with 'O' ring sealing.

  9. Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

    KAUST Repository

    Ruzziconi, Laura

    2016-12-05

    This study deals with the nonlinear dynamics arising in an atomic force microscope cantilever beam. After analyzing the static behavior, a single degree of freedom Galerkin reduced order model is introduced, which describes the overall scenario of the structure response in a neighborhood of the primary resonance. Extensive numerical simulations are performed when both the forcing amplitude and frequency are varied, ranging from low up to elevated excitations. The coexistence of competing attractors with different characteristics is analyzed. Both the non-resonant and the resonant behavior are observed, as well as ranges of inevitable escape. Versatility of behavior is highlighted, which may be attractive in applications. Special attention is devoted to the effects of the tip-sample separation distance, since this aspect is of fundamental importance to understand the operation of an AFM. We explore the metamorphoses of the multistability region when the tip-sample separation distance is varied. To have a complete description of the AFM response, comprehensive behavior charts are introduced to detect the theoretical boundaries of appearance and disappearance of the main attractors. Also, extensive numerical simulations investigate the AFM response when both the forcing amplitude and the tip-sample separation distance are considered as control parameters. The main features are analyzed in detail and the obtained results are interpreted in terms of oscillations of the cantilever-tip ensemble. However, we note that all the aforementioned results represent the limit when disturbances are absent, which never occurs in practice. Here comes the importance of overcoming local investigations and exploring dynamics from a global perspective, by introducing dynamical integrity concepts. To extend the AFM results to the practical case where disturbances exist, we develop a dynamical integrity analysis. After performing a systematic basin of attraction analysis, integrity

  10. Physical characterization of single convergent beam device for teletherapy: theoretical and Monte Carlo approach.

    Science.gov (United States)

    Figueroa, R G; Valente, M

    2015-09-21

    The main purpose of this work is to determine the feasibility and physical characteristics of a new teletherapy device of radiation therapy based on the application of a convergent x-ray beam of energies like those used in radiotherapy providing highly concentrated dose delivery to the target. We have denominated it Convergent Beam Radio Therapy (CBRT). Analytical methods are developed first in order to determine the dosimetry characteristic of an ideal convergent photon beam in a hypothetical water phantom. Then, using the PENELOPE Monte Carlo code, a similar convergent beam that is applied to the water phantom is compared with that of the analytical method. The CBRT device (Converay(®)) is designed to adapt to the head of LINACs. The converging beam photon effect is achieved thanks to the perpendicular impact of LINAC electrons on a large thin spherical cap target where Bremsstrahlung is generated (high-energy x-rays). This way, the electrons impact upon various points of the cap (CBRT condition), aimed at the focal point. With the X radiation (Bremsstrahlung) directed forward, a system of movable collimators emits many beams from the output that make a virtually definitive convergent beam. Other Monte Carlo simulations are performed using realistic conditions. The simulations are performed for a thin target in the shape of a large, thin, spherical cap, with an r radius of around 10-30 cm and a curvature radius of approximately 70 to 100 cm, and a cubed water phantom centered in the focal point of the cap. All the interaction mechanisms of the Bremsstrahlung radiation with the phantom are taken into consideration for different energies and cap thicknesses. Also, the magnitudes of the electric and/or magnetic fields, which are necessary to divert clinical-use electron beams (0.1 to 20 MeV), are determined using electromagnetism equations with relativistic corrections. This way the above-mentioned beam is manipulated and guided for its perpendicular impact

  11. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...

  12. The GlueX Start Counter and Beam Asymmetry$\\Sigma$ in Single $\\pi^{0}$ Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Pooser, Eric [Florida Intl Univ., Miami, FL (United States)

    2016-03-26

    The GlueX experiment aims to study meson photoproduction while utilizing the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid H2 target. A Start Counter detector was fabricated to properly identify the accelerator electron beam buckets and to provide accurate timing information. The Start Counter detector was designed to operate at photon intensities of up to 108 γ/s in the coherent peak and provides a timing resolution ~300 ps so as to provide successful identification of the electron beam buckets to within 99% accuracy. Furthermore, the Start Counter detector provides excellent solid angle coverage, ~ 90% of 4π hermeticity, and a high degree of segmentation for background rejection. It consists of a cylindrical array of 30 scintillators with pointed ends that bend towards the beam at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were selected as the readout system. An initial measurement of the beam asymmetry Sigma in the exclusive reaction γ$\\vec{p}$→ π0p, where π0 → γ has been carried out utilizing the GlueX spectrometer during the Spring 2015 commissioning run. The tagged photon energies ranged from 2.5≤ Eγ ≤ 3.0 GeV in the coherent peak. These measurements were then compared to the world data set and show remarkable agreement with only two hours of physics production running.

  13. Swing-arm beam erector (SABER) concept for single astronaut assembly of space structure

    Science.gov (United States)

    Watson, J. J.; Heard, W. L., Jr.; Jensen, J. K.

    1985-01-01

    Results are presented of tests conducted to evaluate a mobile work station/assembly fixture concept that would mechanically assist an astronaut in the on-orbit manual assembly of erectable truss-beams. The concept eliminates astronaut manual translation by use of a motorized work platform with foot restraints. The tests involved assembly of a tetrahedral truss-beam by a test subject in simulated zero gravity (neutral bouyancy in water). A three-bay truss-beam was assembled from 30 aluminum struts with quick-attachment structural joints. The results show that average on-orbit assembly rates of 2.1 struts per minute can be expected for struts of the size employed in these tests.

  14. Simulation, Experimental and Analitical Study of Deflection at End Curved Beam Affected by Single Concentrated Load

    Directory of Open Access Journals (Sweden)

    Dewa Ngakan Ketut Putra Negara

    2012-11-01

    Full Text Available Deflection has an important role in order to design structure or machine component, beside consideration of stresscalculation. This is due to although stress is still smaller then stress allowed by material strength, but probably happen thatdeflection exceeds limit allowed. That condition affects serious hazard on machine elements or structure due to it can affectof component deviate from its main function. One of element which is often experience of deflection is beam. Beams playsignificant roles in many engineering applications, including buildings, bridges, automobiles, and airplane structures. In thisresearch, material to be used was Steel ASTM 1060, with specimen in the form of curved beam. Physical condition of beamwas modeled use of BEAM3 2D. Variation of loads to be applied were W = 100, 150, 200, 250, 300, 350, 400, 450, 500, and550 gr in vertical direction. The result of simulation was verificated by analytical and experimental data. Evaluation wascarried out by statistical test (t-test. The result of simulation is categorized to be good if the result of simulation is samewith analytical and experimental data. The result of research shows that loading has a significant effect on the deflection.The higher load affect the higher of deflection Modeling use of BEAM3 2D gave good result of deflection. This is showedfrom t-test have done, where the result of simulation was same with analytical and experimental data. Other advantage ofsimulation was deflection result obtained was not limited only at the end of beam, but it can predict of deflection at eachnode or point desired

  15. High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

    CERN Document Server

    Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

    2003-01-01

    A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

  16. Development of seersucker fabrics using single warp beam and modelling of their stretch-recovery behaviour

    NARCIS (Netherlands)

    Maqsood, Muhammad

    2014-01-01

    Seersucker is a thin and puckered fabric used to make clothing for spring. Due to its specific structure, this fabric is held away from the skin when worn, facilitating heat dissipation and air circulation. Seersucker is produced by slack tension weaving using two warp beams. Due to the use of two

  17. SU-F-J-211: Scatter Correction for Clinical Cone-Beam CT System Using An Optimized Stationary Beam Blocker with a Single Scan

    Energy Technology Data Exchange (ETDEWEB)

    Liang, X; Zhang, Z; Xie, Y [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, GuangDong (China); Gong, S; Niu, T [Department of Radiation Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang (China); Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang (China); Zhou, Q [Department of Radiation Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang (China)

    2016-06-15

    Purpose: X-ray scatter photons result in significant image quality degradation of cone-beam CT (CBCT). Measurement based algorithms using beam blocker directly acquire the scatter samples and achieve significant improvement on the quality of CBCT image. Within existing algorithms, single-scan and stationary beam blocker proposed previously is promising due to its simplicity and practicability. Although demonstrated effectively on tabletop system, the blocker fails to estimate the scatter distribution on clinical CBCT system mainly due to the gantry wobble. In addition, the uniform distributed blocker strips in our previous design results in primary data loss in the CBCT system and leads to the image artifacts due to data insufficiency. Methods: We investigate the motion behavior of the beam blocker in each projection and design an optimized non-uniform blocker strip distribution which accounts for the data insufficiency issue. An accurate scatter estimation is then achieved from the wobble modeling. Blocker wobble curve is estimated using threshold-based segmentation algorithms in each projection. In the blocker design optimization, the quality of final image is quantified using the number of the primary data loss voxels and the mesh adaptive direct search algorithm is applied to minimize the objective function. Scatter-corrected CT images are obtained using the optimized blocker. Results: The proposed method is evaluated using Catphan@504 phantom and a head patient. On the Catphan©504, our approach reduces the average CT number error from 115 Hounsfield unit (HU) to 11 HU in the selected regions of interest, and improves the image contrast by a factor of 1.45 in the high-contrast regions. On the head patient, the CT number error is reduced from 97 HU to 6 HU in the soft tissue region and image spatial non-uniformity is decreased from 27% to 5% after correction. Conclusion: The proposed optimized blocker design is practical and attractive for CBCT guided radiation

  18. SU-F-J-211: Scatter Correction for Clinical Cone-Beam CT System Using An Optimized Stationary Beam Blocker with a Single Scan

    International Nuclear Information System (INIS)

    Liang, X; Zhang, Z; Xie, Y; Gong, S; Niu, T; Zhou, Q

    2016-01-01

    Purpose: X-ray scatter photons result in significant image quality degradation of cone-beam CT (CBCT). Measurement based algorithms using beam blocker directly acquire the scatter samples and achieve significant improvement on the quality of CBCT image. Within existing algorithms, single-scan and stationary beam blocker proposed previously is promising due to its simplicity and practicability. Although demonstrated effectively on tabletop system, the blocker fails to estimate the scatter distribution on clinical CBCT system mainly due to the gantry wobble. In addition, the uniform distributed blocker strips in our previous design results in primary data loss in the CBCT system and leads to the image artifacts due to data insufficiency. Methods: We investigate the motion behavior of the beam blocker in each projection and design an optimized non-uniform blocker strip distribution which accounts for the data insufficiency issue. An accurate scatter estimation is then achieved from the wobble modeling. Blocker wobble curve is estimated using threshold-based segmentation algorithms in each projection. In the blocker design optimization, the quality of final image is quantified using the number of the primary data loss voxels and the mesh adaptive direct search algorithm is applied to minimize the objective function. Scatter-corrected CT images are obtained using the optimized blocker. Results: The proposed method is evaluated using Catphan@504 phantom and a head patient. On the Catphan©504, our approach reduces the average CT number error from 115 Hounsfield unit (HU) to 11 HU in the selected regions of interest, and improves the image contrast by a factor of 1.45 in the high-contrast regions. On the head patient, the CT number error is reduced from 97 HU to 6 HU in the soft tissue region and image spatial non-uniformity is decreased from 27% to 5% after correction. Conclusion: The proposed optimized blocker design is practical and attractive for CBCT guided radiation

  19. Beam Test Results for Single- and Double-Sided Silicon Detector Prototypes of the CMS Central Detector

    CERN Document Server

    Adriani, O

    1997-01-01

    We report the results of two beam tests performed in July and September 1995 at CERN using silicon microstrip detectors of various types: single sided, double sided with small angle stereo strips, double sided with orthogonal strips, double sided with pads. For the read-out electronics use was made of Preshape32, Premux128 and VA1 chips. The signal to noise ratio and the resolution of the detectors was studied for different incident angles of the incoming particles and for different values of the detector bias voltage. The goal of these tests was to check and improve the performances of the prototypes for the CMS Central Detector.

  20. Development of a dual ion beam system with single accelerator for materials studies

    International Nuclear Information System (INIS)

    Suzuki, Kazumichi; Nishimura, Eiichi; Hashimoto, Tsuneyuki

    1986-01-01

    The dual ion beam accelerator system has been developed for simulation studies of neutron radiation damage of structural materials for nuclear fusion and fission reactors. One accelerator is used to accelerate two different kinds of ions, which are generated in the ion source simultaneously. One of these ions is selected alternatively by switching the magnetic field of the analyzing magnet, and is then accelerated to the desired energy value. The system is controlled by a microcomputer. The accelerator used in the system is a conventional 400 kV Cockcroft-Walton accelerator. The performance test by the acceleration of He + and Ar + shows that the system is capable of accelerating two ions alternatively with a switching time of less than 22 s. The beam current obtained with the microcomputer control is more than 98% of the current obtained by manual operation. (orig.)

  1. Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams

    KAUST Repository

    Alcheikh, Nouha

    2016-05-06

    This paper presents an experimental study and a finite-element analysis of the effect of squeeze film damping on the resonance frequency and quality factor of the higher-order flexure vibrations modes of clamped-clamped microbeams. Viscoelastic and silicon nitride microbeams are fabricated and are electrostatically actuated by various electrode configurations to trigger the first, second, and third modes. The damping characteristic and the resonance frequency of these modes are examined for a wide range of gas pressure and electrostatic voltage loads. The results of the silicon nitride beams and viscoelastic beams are compared. It is found that the intrinsic material loss is the major dissipation mechanism at low pressure for the viscoelastic microbeams, significantly limiting their quality factor. It is also found that while the silicon nitride beams show higher quality factors at the intrinsic and molecular regimes of pressure, due to their low intrinsic loss, their quality factors near atmospheric pressure are lower than those of the viscoelastic microbeams. Further, the higher-order modes of all the beams show much higher quality factors at atmospheric pressure compared to the first mode, which could be promising for operating such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.

  2. A Single Pulse Beam Emittance Measurement for the CERN Heavy Ion Linac

    CERN Document Server

    Crescenti, M

    1995-01-01

    A new device for transverse emittance measurement has been installed in the 4.2 MeV/u filter region of the CERN Heavy Ion Linac (Linac 3). It allows to obtain pulse-to-pulse (every 1.2 sec) visualisation of the Linac 3 beam parameters in order to tune the machine and to match the beam for injection into the first circular accelerator, the PS Booster. The system is based on the "multi-slit" technique similar to the well-known "pepper pot" method. A plate with a series of horizontal or vertical slits is placed in the beam, defining positions in the phase plane. Particles pass through the slits and drift to a scintillator screen where they produce light. The screen is looked at by an externally triggered high resolution CCD camera. For each slit position the light intensity distribution, in the limit of infinitesimal slit aperture, is proportional to the angle distribution of the particles and therefore, provides the angular distribution in the phase plane. The video signal from the camera is digitised and the r...

  3. Reducing blood loss during laparoscopic myomectomy by temporary uterine artery clamping using bulldog clamp

    Directory of Open Access Journals (Sweden)

    Kai-Jo Chiang

    2014-01-01

    Full Text Available Uterine myoma is the most common benign gynecologic tumor worldwide. Mini-invasive surgery has become popular for myomectomy, with advantages over laparotomy. However, reducing blood loss during laparoscopic myomectomy is a major concern for the surgeon because of the limitation in making a quick control bleeding during the operation. Several methods have proved to decrease blood flow, but are not always effective or available. We present a case of uterine myoma with the uterine arteries clamped by bulldog clamps during laparoscopic myomectomy. The myoma was removed successfully with minimal blood loss (<50 ml during the operation. This is an effective, safe, and reliable method for reducing bleeding during laparoscopic myomectomy that does not require ligation of the uterine artery.

  4. HOM (higher-order mode) test of the storage ring single-cell cavity with a 20-MeV e- beam for the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Song, J.; Kang, Y.W.; Kustom, R.

    1993-01-01

    To test the effectiveness of damping techniques of the APS storage ring single-cell cavity, a beamline has been designed and assembled to use the ANL Chemistry Division linac beam (20-MeV, FWHM of 20 ps). A single-cell cavity will be excited by the electron beam to investigate the effect on higher-order modes (HOMs) with and without coaxial dampers (H-loop damper, E-probe damper), and wideband aperture dampers. In order for the beam to propagate on- and off-center of the cavity, the beamline consists of two sections -- a beam collimating section and a cavity measurement section -- separated by two double Aluminum foil windows. RF cavity measurements were made with coupling loops and E-probes. The results are compared with both the TBCI calculations and 'cold' measurements with the bead-perturbation method. The data acquisition system and beam diagnostics will be described in a separate paper

  5. Full characterization of laser-accelerated ion beams using Faraday cup, silicon carbide, and single-crystal diamond detectors

    Science.gov (United States)

    Margarone, D.; Krása, J.; Giuffrida, L.; Picciotto, A.; Torrisi, L.; Nowak, T.; Musumeci, P.; Velyhan, A.; Prokůpek, J.; Láska, L.; Mocek, T.; Ullschmied, J.; Rus, B.

    2011-05-01

    Multi-MeV beams of light ions have been produced using the 300 picosecond, kJ-class iodine laser, operating at the Prague Asterix Laser System facility in Prague. Real-time ion diagnostics have been performed by the use of various time-of-flight (TOF) detectors: ion collectors (ICs) with and without absorber thin films, new prototypes of single-crystal diamond and silicon carbide detectors, and an electrostatic ion mass spectrometer (IEA). In order to suppress the long photopeak induced by soft X-rays and to avoid the overlap with the signal from ultrafast particles, the ICs have been shielded with Al foil filters. The application of large-bandgap semiconductor detectors (>3 eV) ensured cutting of the plasma-emitted visible and soft-UV radiation and enhancing the sensitivity to the very fast proton/ion beams. Employing the IEA spectrometer, various ion species and charge states in the expanding laser-plasma have been determined. Processing of the experimental data based on the TOF technique, including estimation of the plasma fast proton maximum and peak energy, ion beam currents and total charge, total number of fast protons, as well as deconvolution processes, ion stopping power, and ion/photon transmission calculations for the different metallic filters used, are reported.

  6. Frequency Characteristics of Surface Wave Generated by Single-Line Pulsed Laser Beam with Two Kinds of Spatial Energy Profile Models: Gaussian and Square-Like

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ho Geon; Kim, Myung Hwan; Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of)

    2012-08-15

    Using a single-line pulsed laser beam is well known as a useful noncontact method to generate a directional surface acoustic wave. In this method, different laser beam energy profiles produce different waveforms and frequency characteristics. In this paper, we considered two typical kinds of laser beam energy profiles, Gaussian and square-like, to find out a difference in the frequency characteristics. To achieve this, mathematical models were proposed first for Gaussian laser beam profile and square-like respectively, both of which depended on the laser beam width. To verify the theoretical models, experimental setups with a cylindrical lens and a line-slit mask were respectively designed to produce a line laser beam with Gaussian spatial energy profile and square-like. The frequency responses of the theoretical models showed good agreement with experimental results in terms of the existence of harmonic frequency components and the shift of the first peak frequencies to low.

  7. Thermodynamic basis for engineering high-affinity, high-specificity binding-induced DNA clamp nanoswitches.

    Science.gov (United States)

    Idili, Andrea; Plaxco, Kevin W; Vallée-Bélisle, Alexis; Ricci, Francesco

    2013-12-23

    Naturally occurring chemoreceptors almost invariably employ structure-switching mechanisms, an observation that has inspired the use of biomolecular switches in a wide range of artificial technologies in the areas of diagnostics, imaging, and synthetic biology. In one mechanism for generating such behavior, clamp-based switching, binding occurs via the clamplike embrace of two recognition elements onto a single target molecule. In addition to coupling recognition with a large conformational change, this mechanism offers a second advantage: it improves both affinity and specificity simultaneously. To explore the physics of such switches we have dissected here the thermodynamics of a clamp-switch that recognizes a target DNA sequence through both Watson-Crick base pairing and triplex-forming Hoogsteen interactions. When compared to the equivalent linear DNA probe (which relies solely on Watson-Crick interactions), the extra Hoogsteen interactions in the DNA clamp-switch increase the probe's affinity for its target by ∼0.29 ± 0.02 kcal/mol/base. The Hoogsteen interactions of the clamp-switch likewise provide an additional specificity check that increases the discrimination efficiency toward a single-base mismatch by 1.2 ± 0.2 kcal/mol. This, in turn, leads to a 10-fold improvement in the width of the "specificity window" of this probe relative to that of the equivalent linear probe. Given these attributes, clamp-switches should be of utility not only for sensing applications but also, in the specific field of DNA nanotechnology, for applications calling for a better control over the building of nanostructures and nanomachines.

  8. Femtosecond single-beam direct laser poling of stable and efficient second-order nonlinear optical properties in glass

    International Nuclear Information System (INIS)

    Papon, G.; Marquestaut, N.; Royon, A.; Canioni, L.; Petit, Y.; Dussauze, M.; Rodriguez, V.; Cardinal, T.

    2014-01-01

    We depict a new approach for the localized creation in three dimensions (3D) of a highly demanded nonlinear optical function for integrated optics, namely second harmonic generation. We report on the nonlinear optical characteristics induced by single-beam femtosecond direct laser writing in a tailored silver-containing phosphate glass. The original spatial distribution of the nonlinear pattern, composed of four lines after one single laser writing translation, is observed and modeled with success, demonstrating the electric field induced origin of the second harmonic generation. These efficient second-order nonlinear structures (with χ eff (2)  ∼ 0.6 pm V −1 ) with sub-micron scale are impressively stable under thermal constraint up to glass transition temperature, which makes them very promising for new photonic applications, especially when 3D nonlinear architectures are desired

  9. GaN Schottky diodes with single-crystal aluminum barriers grown by plasma-assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, H. Y.; Yang, W. C.; Lee, P. Y.; Lin, C. W.; Cheng, Kai-Yuan; Hsieh, K. C.; Cheng, K. Y., E-mail: kycheng@ee.nthu.edu.tw [Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hsu, C.-H. [Division of Scientific Research, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

    2016-08-22

    GaN-based Schottky barrier diodes (SBDs) with single-crystal Al barriers grown by plasma-assisted molecular beam epitaxy are fabricated. Examined using in-situ reflection high-energy electron diffractions, ex-situ high-resolution x-ray diffractions, and high-resolution transmission electron microscopy, it is determined that epitaxial Al grows with its [111] axis coincident with the [0001] axis of the GaN substrate without rotation. In fabricated SBDs, a 0.2 V barrier height enhancement and 2 orders of magnitude reduction in leakage current are observed in single crystal Al/GaN SBDs compared to conventional thermal deposited Al/GaN SBDs. The strain induced piezoelectric field is determined to be the major source of the observed device performance enhancements.

  10. A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

    Energy Technology Data Exchange (ETDEWEB)

    Waidyawansa, Dinayadura Buddhini [Ohio Univ., Athens, OH (United States)

    2013-08-01

    The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.

  11. Single-shot measurements of low emittance beams from laser-plasma accelerators comparing two triggered injection methods

    Science.gov (United States)

    van Tilborg, Jeroen

    2017-10-01

    The success of laser plasma accelerator (LPA) based applications, such as a compact x-ray free electron laser (FEL), relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot energy-dispersed emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock-induced density down-ramp injection. Both injection mechanisms have gained in popularity in recent years due to their demonstrated stable LPA performance. For the down-ramp injection configuration, normalized emittances a factor of two lower were recorded: less than 1 micron at spectral charge densities up to 2 pC/MeV. For both injection mechanisms, a contributing correlation of space charge to the emittance was identified. This measurement technique in general, and these results specifically, are critical to the evaluation of LPA injection methods and development of high-quality LPA beam lines worldwide. This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the U.S. DOE NNSA, DNN R&D (NA22), by the National Science Foundation under Grant No. PHY-1415596, and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

  12. Evaluation of clamp effects on LMFBR piping systems

    International Nuclear Information System (INIS)

    Jones, G.L.

    1980-01-01

    Loop-type liquid metal breeder reactor plants utilize thin-wall piping to mitigate through-wall thermal gradients due to rapid thermal transients. These piping loops require a support system to carry the combined weight of the pipe, coolant and insulation and to provide attachments for seismic restraints. The support system examined here utilizes an insulated pipe clamp designed to minimize the stresses induced in the piping. To determine the effect of these clamps on the pipe wall a non-linear, two-dimensional, finite element model of the clamp, insulation and pipe wall was used to determine the clamp/pipe interface load distributions which were then applied to a three-dimensional, finite element model of the pipe. The two-dimensional interaction model was also utilized to estimate the combined clamp/pipe stiffness

  13. Epitaxial growth and new phase of single crystal Dy by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Yang, Kai-Yueh; Homma, Hitoshi; Schuller, I.K.

    1987-09-01

    We have grown two novel epitaxial phases of dysprosium (Dy) on vanadium (V) by molecular beam epitaxy technique. Surface and bulk structures are studied by in-situ reflection high energy electron diffraction (RHEED) and x-ray diffraction techniques. The new hcp phases are ∼4% expanded uniformly in-plane (0001), and ∼9% and ∼4% expanded out of plane along the c-axes for non-interrupted and interrupted deposition case, respectively. We also observed (2 x 2), (3 x 3), and (4 x 4) Dy surface reconstruction patterns and a series of transitions as the Dy film thickness increases. 12 refs., 3 figs

  14. An absorptive single-pole four-throw switch using multiple-contact MEMS switches and its application to a monolithic millimeter-wave beam-forming network

    International Nuclear Information System (INIS)

    Lee, Sanghyo; Kim, Jong-Man; Kim, Yong-Kweon; Kwon, Youngwoo

    2009-01-01

    In this paper, a new absorptive single-pole four-throw (SP4T) switch based on multiple-contact switching is proposed and integrated with a Butler matrix to demonstrate a monolithic beam-forming network at millimeter waves (mm waves). In order to simplify the switching driving circuit and reduce the number of unit switches in an absorptive SP4T switch, the individual switches were replaced with long-span multiple-contact switches using stress-free single-crystalline-silicon MEMS technology. This approach improves the mechanical stability as well as the manufacturing yield, thereby allowing successful integration into a monolithic beam former. The fabricated absorptive SP4T MEMS switch shows insertion loss less than 1.3 dB, return losses better than 11 dB at 30 GHz and wideband isolation performance higher than 39 dB from 20 to 40 GHz. The absorptive SP4T MEMS switch is integrated with a 4 × 4 Butler matrix on a single chip to implement a monolithic beam-forming network, directing beam into four distinct angles. Array factors from the measured data show that the proposed absorptive SPnT MEMS switch can be effectively used for high-performance mm-wave beam-switching systems. This work corresponds to the first demonstration of a monolithic beam-forming network using switched beams

  15. Multi-physics modeling of single/multiple-track defect mechanisms in electron beam selective melting

    International Nuclear Information System (INIS)

    Yan, Wentao; Ge, Wenjun; Qian, Ya; Lin, Stephen; Zhou, Bin; Liu, Wing Kam; Lin, Feng; Wagner, Gregory J.

    2017-01-01

    Metallic powder bed-based additive manufacturing technologies have many promising attributes. The single track acts as one fundamental building unit, which largely influences the final product quality such as the surface roughness and dimensional accuracy. A high-fidelity powder-scale model is developed to predict the detailed formation processes of single/multiple-track defects, including the balling effect, single track nonuniformity and inter-track voids. These processes are difficult to observe in experiments; previous studies have proposed different or even conflicting explanations. Our study clarifies the underlying formation mechanisms, reveals the influence of key factors, and guides the improvement of fabrication quality of single tracks. Additionally, the manufacturing processes of multiple tracks along S/Z-shaped scan paths with various hatching distance are simulated to further understand the defects in complex structures. The simulations demonstrate that the hatching distance should be no larger than the width of the remelted region within the substrate rather than the width of the melted region within the powder layer. Thus, single track simulations can provide valuable insight for complex structures.

  16. Cell-Detection Technique for Automated Patch Clamping

    Science.gov (United States)

    McDowell, Mark; Gray, Elizabeth

    2008-01-01

    A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

  17. Single-bunch beam breakup in a dielectric-lined waveguide

    International Nuclear Information System (INIS)

    Ng, King-Yuen.

    1992-08-01

    We examine beam breakup of a 100 nC I mm-long (rms) source bunch inside a cylindrical dielectric waveguide, with dielectric ε = 2.65 filling the radius between 7.5 and 9.0 mm. Only ∼ 78% of the bunch with an initial offset of 0.3 mm survives the passage of the 3.75 m waveguide. The loss is mainly due to the large deflections of some particles that are slowed down to nearly zero velocity. As a result, quadrupole focussing of any sort will not help. However, if the waveguide is shortened to 3.3 m, the loss reduces to only 5.5%

  18. Load-deflection characteristics of small bore insulated pipe clamps

    International Nuclear Information System (INIS)

    Severud, L.K.; Clark, G.L.

    1982-01-01

    High temperature LMFBR piping is subject to rapid temperature changes during transient events. Typically, this pipe is supported by specially designed insulated pipe clamps to prevent excessive thermal stress from developing during these transients. The special insulated clamps used on both FFTF and CRBR piping utilize a Belleville spring arrangement to compensate for pipe thermal expansion. Analysis indicates that this produces a non-linear, directionally sensitive clamp spring rate. Since these spring rates influence the seismic response of a supported piping system, it was deemed necessary to evaluate them further by test. This has been accomplished for the FFTF clamps. A more standard insulated pipe clamp, which does not incorporate Belleville springs to accommodate thermal expansion, was also tested. This type clamp is simple in design, and economically attractive. It may have wide application prospects for use in LMFBR small bore auxiliary piping operating at temperatures below 427 0 C. Load deflection tests were conducted on 2.54 CM and 7.62 CM diameter samples of these commercial clamps

  19. Single bunch beam loading experiments on the SLAC two-mile accelerator

    International Nuclear Information System (INIS)

    Koontz, R.F.; Loew, G.A.; Miller, R.H.

    1975-01-01

    Several experimental improvements were used in the generation of new data on the dependence of single bunch radiation loss as a function of energy. These results are given, along with an empirical theory to explain these results. The experimental technique used is reviewed. (PMA)

  20. Concept and properties of an infrared hybrid single-beam spectrum and its application to eliminate solvent bands and other background interferences.

    Science.gov (United States)

    Chen, Yujing; Wang, Hai-Shui; Morisawa, Yusuke; Ozaki, Yukihiro

    2014-02-01

    For infrared (IR) spectral measurements, if a quality single-beam background spectrum with desired intensity could be obtained, the contributions from solvent and other background components could be completely suppressed and their bands would not appear in a final transmittance/absorbance spectrum. In order to achieve this ideal but difficult goal, the concept of hybrid single-beam spectrum is introduced in this paper. The hybrid single-beam spectrum (φ h) is defined as a mixture of two single-beam spectra (φ b1 and φ b2) of the same sample but with different pathlengths (b1 and b2), namely, φ h = αφ b1+(1-α)φ b2, where α (0 ≤ α ≤ 1) is the component factor. The properties of the hybrid spectrum have been investigated. Under conditions of b2 > b1 ≥ 0.7 b2 and A max ≤ 0.60 (Amax is the maximum absorbance of b2 sample in the spectral range of interest), all the synthesized hybrid spectra are free from significant distortion regardless of the component factor. Therefore, the hybrid single-beam spectrum with desired intensity can be easily obtained simply by choosing an appropriate component factor. The proposed methodology has been demonstrated experimentally by the complete removal of the interference from the atmospheric water vapor and solvent. © 2013 Elsevier B.V. All rights reserved.

  1. Is "Delayed Umbilical Cord Clamping" Beneficial for Premature Newborns?

    Directory of Open Access Journals (Sweden)

    Amir-Mohammad Armanian

    2017-05-01

    Full Text Available Background: The appropriate moment for clamping the umbilical cord is controversial. Immediate cord clamping (ICC is an item of active management of the third stage of labor (AMTSL. Unclamped umbilical cord may cause inconvenience in preterm neonates because they commonly need some levels of emergent services. Some studies revealed delayed cord clamping (DCC of preterm neonates results in better health conditions like lower rates of respiratory distress syndrome (RDS, less morbidities in labor room and lower risk of postpartum hemorrhage. The aim of the present study was to determine the effect of delayed umbilical cord clamping on premature neonatal outcomes. Materials and Methods: In this single‑center randomized control trial study, sixty premature neonates (gestational age ≤ 34 weeks were randomly assigned to ICC (cord clamped at 5–10 seconds or DCC (30–45 seconds groups and followed up in neonatal intensive care unit (NICU. Primary outcomes were 1st and 5th minute Apgar score, average of level of hematocrit after birth, intra ventricle hemorrhage and need some levels of resuscitation. Results: Differences in demographic characteristics were not statistically significant. After birth, neonates who had delayed clamping had significantly higher mean hematocrit after at 4-hour of birth (49.58+5.15gr/dl vs. 46.58+5.40gr/dlin DCC vs. ICC groups, respectively (P=0.031. Delayed cord clamping reduced the duration of need to nasal continues positive airway pressure (NCPAP (86.7% and 60.0% in ICC and DCC groups, respectively, P= 0.039. Attractively, the results showed lower incidence of clinical sepsis in delayed cord clamping neonates (53.3% vs. 23.3% in ICC and DCC groups, respectively, P=0.033. Conclusion: Prematurity complications might decrease by delay umbilical cord clamping which improve the hematocrit, duration of need to NCPAP and incidence of clinical sepsis. Furthermore, DCC may have no negative impact on neonatal resuscitation.

  2. Effect of the long-term memory on the beam break-up instability of a single bunch in storage rings

    International Nuclear Information System (INIS)

    Pestrikov, D.V.

    2009-01-01

    We study modifications of the beam break-up instability of transverse coherent oscillations of a single bunch which occur in storage rings due to weak wakefields decaying longer than the revolution period of particles. The long-term part of the wake results in the eigenmode spectra of coherent oscillations. Both stable and unstable modes are found for coherent oscillations of a monochromatic bunch. The single turn wakefields result in the beam break-up coherent oscillations of the bunch. The found eigenmode spectrum does not contain a leading unstable mode. Despite the exponential increase in time of the eigenmodes, both self-consistent and the beam break-up parts of the coherent oscillations indicate similar and non-exponential time dependencies. The beam break-up behavior dominates, if the wake memory is weak.

  3. Thon rings from amorphous ice and implications of beam-induced Brownian motion in single particle electron cryo-microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McMullan, G., E-mail: gm2@mrc-lmb.cam.ac.uk; Vinothkumar, K.R.; Henderson, R.

    2015-11-15

    We have recorded dose-fractionated electron cryo-microscope images of thin films of pure flash-frozen amorphous ice and pre-irradiated amorphous carbon on a Falcon II direct electron detector using 300 keV electrons. We observe Thon rings [1] in both the power spectrum of the summed frames and the sum of power spectra from the individual frames. The Thon rings from amorphous carbon images are always more visible in the power spectrum of the summed frames whereas those of amorphous ice are more visible in the sum of power spectra from the individual frames. This difference indicates that while pre-irradiated carbon behaves like a solid during the exposure, amorphous ice behaves like a fluid with the individual water molecules undergoing beam-induced motion. Using the measured variation in the power spectra amplitude with number of electrons per image we deduce that water molecules are randomly displaced by a mean squared distance of ∼1.1 Å{sup 2} for every incident 300 keV e{sup −}/Å{sup 2}. The induced motion leads to an optimal exposure with 300 keV electrons of 4.0 e{sup −}/Å{sup 2} per image with which to observe Thon rings centred around the strong 3.7 Å scattering peak from amorphous ice. The beam-induced movement of the water molecules generates pseudo-Brownian motion of embedded macromolecules. The resulting blurring of single particle images contributes an additional term, on top of that from radiation damage, to the minimum achievable B-factor for macromolecular structure determination. - Highlights: • Thon rings can be seen from amorphous ice. • Radiation damage to amorphous ice randomly displaces water molecules. • Each incident 300 keV e{sup −}/Å{sup 2} displaces water molecules on average by ∼1 Å. • Macromolecules embedded in amorphous ice undergo beam induced Brownian motion.

  4. Electromagnetic fields created by a beam in an axisymmetric infinitely thick single-layer resistive pipe: general formulas and low frequency approximations

    CERN Document Server

    Mounet, Nicolas Frank; CERN. Geneva. ATS Department

    2015-01-01

    This note provides general and approximate formulas for the electromagnetic fields created by a passing beam in an axisymmetric infinitely thick resistive pipe made of a single homogeneous layer. The full derivations and their resulting approximate expressions at low and intermediate frequencies are given here, as well as the conditions under which those approximations are valid. Beam-coupling impedances are also computed, and examples are shown.

  5. Advanced metal lift-off process using electron-beam flood exposure of single-layer photoresist

    Science.gov (United States)

    Minter, Jason P.; Ross, Matthew F.; Livesay, William R.; Wong, Selmer S.; Narcy, Mark E.; Marlowe, Trey

    1999-06-01

    In the manufacture of many types of integrated circuit and thin film devices, it is desirable to use a lift-of process for the metallization step to avoid manufacturing problems encountered when creating metal interconnect structures using plasma etch. These problems include both metal adhesion and plasma etch difficulties. Key to the success of the lift-off process is the creation of a retrograde or undercut profile in the photoresists before the metal deposition step. Until now, lift-off processing has relied on costly multi-layer photoresists schemes, image reversal, and non-repeatable photoresist processes to obtain the desired lift-off profiles in patterned photoresist. This paper present a simple, repeatable process for creating robust, user-defined lift-off profiles in single layer photoresist using a non-thermal electron beam flood exposure. For this investigation, lift-off profiles created using electron beam flood exposure of many popular photoresists were evaluated. Results of lift-off profiles created in positive tone AZ7209 and ip3250 are presented here.

  6. Performance Test Results of a Single-sided Silicon Strip Detector with a Radioactive Source and a Proton Beam

    International Nuclear Information System (INIS)

    Ki, Y. I.; Kah, D. H.; Son, D. H.; Kang, H. D.; Kim, H. J.; Kim, H. O.; Bae, J. B.; Ryu, S.; Park, H.; Kim, K. R.

    2007-01-01

    Due to high intrinsic precision and high speed properties of a silicon material, the silicon detector has been used in various applications such as medical imaging detector, radiation detector, positioning detectors in space science and experimental particle physics. High technology, modern equipment, and deep expertise are required to design and fabricate good quality of silicon sensors. Only few facilities in the world can develop silicon sensors which meet requirements of sensor performances. That is one of main reasons that the silicon sensor is so expensive and it takes time to purchase the silicon sensor once it is ordered. We designed and fabricated AC-coupled single-sided silicon strip sensors and developed front-end electronics and DAQ system to read out sensor signals. The silicon strip sensors were fabricated on a 5-in. n-type silicon wafer which has an orientation, high resistivity (>5 kΩ · cm) and a thickness of 380 μm. We measured the signal-to-noise ratio (SNR) of each channel by using a radioactive source and a 45 MeV proton beam from the MC-50 cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS) in Seoul. We present the measurement results of the SNRs of the silicon strip sensor with a proton beam and radioactive sources

  7. Free vibration of a single-walled carbon nanotube containing a fluid flow using the Timoshenko beam model

    International Nuclear Information System (INIS)

    Chang, W.-J.; Lee, H.-L.

    2009-01-01

    The flexural vibration of the fluid-conveying single-walled carbon nanotube (SWCNT) is derived by the Timoshenko beam model, including rotary inertia and transverse shear deformation. The effects of the flow velocity and the aspect ratio of length to diameter on the vibration frequency and mode shape of the SWCNT are analyzed. Results show that the effects of rotary inertia and transverse shear deformation result in a reduction of the vibration frequencies, especially for higher modes of vibration and short nanotubes. The frequency is also compared with the previous study based on Euler beam model. In addition, if the ratio of length to diameter increased to 60, the influence of the shear deformation and rotary inertia on the mode shape and the resonant frequencies can be neglected. However, the influence is very obvious when the ratio decreased to 20. As the flow velocity of the fluid increases in the vicinity of 2π, the SWCNT reveals the divergence instability. It regains stability when the flow velocity reaches about 9. As the velocity increases further, the SWCNT undergoes a coupled-mode flutter and results in a larger amplitude

  8. Polarization-dependent single-beam laser-induced grating-like effects on titanium films

    International Nuclear Information System (INIS)

    Camacho-Lopez, Santiago; Evans, Rodger; Escobar-Alarcon, Luis; Camacho-Lopez, Miguel A.; Camacho-Lopez, Marco A.

    2008-01-01

    In this paper we present results on polarization-dependent laser-induced effects on titanium (Ti) thin films. We irradiated the titanium films, in ambient air, using a nanosecond Nd:YAG laser (532 nm, 9 ns pulse duration, 10 Hz). Using a series of pulses of fluence well below the ablation threshold, it was possible to form grating-like structures, whose grooves run parallel to the linear polarization of the incident beam. No grating-like structures were obtained when circularly polarized light was used. Our results revealed the remarkable formation of tiny (100 nm and even smaller diameter) craters, which self-arrange quasi-periodically along the ridges (never on the valleys) of the grating-like structure. Optical and scanning electron microscopy were used to study the laser-induced changes on the surface of the titanium films. Micro-Raman spectroscopy was used to analyze the irradiated areas on the titanium films. The Raman analysis demonstrated that the grooves in the grating-like structure, build up from the laser-induced oxidation of titanium. This is the first time, to the best of our knowledge, that periodic surface structures are reported to be induced below the ablation threshold regime, with the grooves made of crystalline metal oxide, in this case TiO 2 in the well-known Rutile phase. The laser irradiated areas on the film acquired selective (upon recording polarization) holographic reflectance

  9. Single orientation graphene synthesized on iridium thin films grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Dangwal Pandey, A., E-mail: arti.pandey@desy.de; Grånäs, E.; Shayduk, R.; Noei, H.; Vonk, V. [Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg (Germany); Krausert, K.; Franz, D.; Müller, P.; Keller, T. F.; Stierle, A., E-mail: andreas.stierle@desy.de [Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg (Germany); Fachbereich Physik, Universität Hamburg, D-22607 Hamburg (Germany)

    2016-08-21

    Heteroepitaxial iridium thin films were deposited on (0001) sapphire substrates by means of molecular beam epitaxy, and subsequently, one monolayer of graphene was synthesized by chemical vapor deposition. The influence of the growth parameters on the quality of the Ir films, as well as of graphene, was investigated systematically by means of low energy electron diffraction, x-ray reflectivity, x-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Our study reveals (111) oriented iridium films with high crystalline quality and extremely low surface roughness, on which the formation of large-area epitaxial graphene is achieved. The presence of defects, like dislocations, twins, and 30° rotated domains in the iridium films is also discussed. The coverage of graphene was found to be influenced by the presence of 30° rotated domains in the Ir films. Low iridium deposition rates suppress these rotated domains and an almost complete coverage of graphene was obtained. This synthesis route yields inexpensive, air-stable, and large-area graphene with a well-defined orientation, making it accessible to a wider community of researchers for numerous experiments or applications, including those which use destructive analysis techniques or irreversible processes. Moreover, this approach can be used to tune the structural quality of graphene, allowing a systematic study of the influence of defects in various processes like intercalation below graphene.

  10. Polarization-dependent single-beam laser-induced grating-like effects on titanium films

    Energy Technology Data Exchange (ETDEWEB)

    Camacho-Lopez, Santiago [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico)], E-mail: camachol@cicese.mx; Evans, Rodger [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico); Escobar-Alarcon, Luis [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico DF 11801 (Mexico); Camacho-Lopez, Miguel A. [Facultad de Medicina, Universidad Autonoma del Estado de Mexico, Paseo Tollocan s/n, esq. Jesus Carranza, Toluca, Estado de Mexico 50120 (Mexico); Camacho-Lopez, Marco A. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Tollocan s/n, esq. Paseo Colon, Toluca, Estado de Mexico, 50110 (Mexico)

    2008-12-30

    In this paper we present results on polarization-dependent laser-induced effects on titanium (Ti) thin films. We irradiated the titanium films, in ambient air, using a nanosecond Nd:YAG laser (532 nm, 9 ns pulse duration, 10 Hz). Using a series of pulses of fluence well below the ablation threshold, it was possible to form grating-like structures, whose grooves run parallel to the linear polarization of the incident beam. No grating-like structures were obtained when circularly polarized light was used. Our results revealed the remarkable formation of tiny (100 nm and even smaller diameter) craters, which self-arrange quasi-periodically along the ridges (never on the valleys) of the grating-like structure. Optical and scanning electron microscopy were used to study the laser-induced changes on the surface of the titanium films. Micro-Raman spectroscopy was used to analyze the irradiated areas on the titanium films. The Raman analysis demonstrated that the grooves in the grating-like structure, build up from the laser-induced oxidation of titanium. This is the first time, to the best of our knowledge, that periodic surface structures are reported to be induced below the ablation threshold regime, with the grooves made of crystalline metal oxide, in this case TiO{sub 2} in the well-known Rutile phase. The laser irradiated areas on the film acquired selective (upon recording polarization) holographic reflectance.

  11. Ion beam modification of thermal stress resistance of MgO single crystals with different crystallographic faces

    International Nuclear Information System (INIS)

    Gurarie, V.N.; Otsuka, P.H.; Williams, J.S.; Conway, M.J.

    2000-01-01

    Ion beam modification of thermal shock stress resistance of MgO single crystals with various crystallographic faces is investigated. The most stable crystal faces in terms of stress and damage resistance are established. Ion implantation is shown to reduce the temperature threshold of fracture for all crystal faces tested. The (111) face is demonstrated to be of highest stability compared to (110) and (100) faces in both implanted and unimplanted crystals. At the same time ion implantation substantially increases the microcrack density for all the faces tested and reduces the degree of fracture damage following thermal shock. The theoretical resistance parameters for various crystal faces are calculated using the continuum mechanics approach. The results are discussed on the basis of fracture mechanics principles and the effect of the implantation-induced lattice damage on crack nucleation

  12. Nucleation of single GaN nanorods with diameters smaller than 35 nm by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Chen, Yen-Ting; Araki, Tsutomu; Palisaitis, Justinas; Persson, Per O. Å.; Olof Holtz, Per; Birch, Jens; Chen, Li-Chyong; Chen, Kuei-Hsien; Nanishi, Yasushi

    2013-01-01

    Nucleation mechanism of catalyst-free GaN nanorod grown on Si(111) is investigated by the fabrication of uniform and narrow (<35 nm) nanorods without a pre-defined mask by molecular beam epitaxy. Direct evidences show that the nucleation of GaN nanorods stems from the sidewall of the underlying islands down to the Si(111) substrate, different from commonly reported ones on top of the island directly. Accordingly, the growth and density control of the nanorods is exploited by a “narrow-pass” approach that only narrow nanorod can be grown. The optimal size of surrounding non-nucleation area around single nanorod is estimated as 88 nm

  13. Nucleation of single GaN nanorods with diameters smaller than 35 nm by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yen-Ting [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China); Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden); Araki, Tsutomu [Department of Electrical and Electronic Engineering, Ritsumeikan University, 525-8577 Shiga (Japan); Palisaitis, Justinas; Persson, Per O. Å.; Olof Holtz, Per; Birch, Jens [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden); Chen, Li-Chyong [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Chen, Kuei-Hsien [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Nanishi, Yasushi [Global Innovation Research Organization, Ritsumeikan University, 525-8577 Shiga (Japan)

    2013-11-11

    Nucleation mechanism of catalyst-free GaN nanorod grown on Si(111) is investigated by the fabrication of uniform and narrow (<35 nm) nanorods without a pre-defined mask by molecular beam epitaxy. Direct evidences show that the nucleation of GaN nanorods stems from the sidewall of the underlying islands down to the Si(111) substrate, different from commonly reported ones on top of the island directly. Accordingly, the growth and density control of the nanorods is exploited by a “narrow-pass” approach that only narrow nanorod can be grown. The optimal size of surrounding non-nucleation area around single nanorod is estimated as 88 nm.

  14. Imperfection Sensitivity of Nonlinear Vibration of Curved Single-Walled Carbon Nanotubes Based on Nonlocal Timoshenko Beam Theory

    Directory of Open Access Journals (Sweden)

    Iman Eshraghi

    2016-09-01

    Full Text Available Imperfection sensitivity of large amplitude vibration of curved single-walled carbon nanotubes (SWCNTs is considered in this study. The SWCNT is modeled as a Timoshenko nano-beam and its curved shape is included as an initial geometric imperfection term in the displacement field. Geometric nonlinearities of von Kármán type and nonlocal elasticity theory of Eringen are employed to derive governing equations of motion. Spatial discretization of governing equations and associated boundary conditions is performed using differential quadrature (DQ method and the corresponding nonlinear eigenvalue problem is iteratively solved. Effects of amplitude and location of the geometric imperfection, and the nonlocal small-scale parameter on the nonlinear frequency for various boundary conditions are investigated. The results show that the geometric imperfection and non-locality play a significant role in the nonlinear vibration characteristics of curved SWCNTs.

  15. Ion beam modification of thermal stress resistance of MgO single crystals with different crystallographic faces

    International Nuclear Information System (INIS)

    Gurarie, V.N.; Otsuka, P.H.; Jamieson, D.N.; Williams, J.S.; Conway, M.

    1999-01-01

    Ion beam modification of thermal shock stress and damage resistance of MgO single crystals with various crystallographic faces is investigated. The most stable crystal faces in terms of stress and damage resistance are established. Ion implantation is shown to reduce the temperature threshold of fracture for all crystal faces tested. The (111) face is demonstrated to be of highest stability compared to (110) and (100) faces in both implanted and unimplanted crystals. At the same time ion implantation substantially increases the microcrack density for the faces tested and reduces the degree of fracture damage following thermal shock. The microcrack density is found to be highest in the crystals with (110) face in comparison with the (001) and (111) faces. The effect is analysed using fracture mechanics principles and discussed in terms of the implantation-induced lattice damage

  16. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method

    International Nuclear Information System (INIS)

    Santos, L.A.; Santos, C.; Souza, R.C.; Ribeiro, S.

    2009-01-01

    In this work, the fracture toughness of different ceramics based on Al 2 O 3 and ZrO 2 were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al 2 O 3 , ZrO 2 (3%Y 2 O 3 ) micro-particled and ZrO 2 (3%Y 2 O 3 ) nanometric, ZrO 2 -Al 2 O 3 and Al 2 O 3 -ZrO 2 composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  17. SU-F-BRE-02: Characterization of a New Commercial Single Crystal Diamond Detector in Photon, Electron and Proton Beams

    International Nuclear Information System (INIS)

    Akino, Y; Das, I

    2014-01-01

    Purpose: Diamond detectors even with superior characteristics have become obsolete due to poor design, selection of crystal and cost. Recently, microDiamond using synthetic single crystal diamond detector (SCDD) is commercially available which is characterized in various radiation beams in this study. Methods: The characteristics of a commercial SCDD model 60019 (PTW) to a 6- and 15-MV photon beams, 6- and 20-MeV electron beams, and 208 MeV proton beams were investigated and compared to the pre-characterized detectors: TN31010 (0.125 cm 3 ) and TN30006 (pinpoint) ionization chambers (PTW), EDGE detector (Sun Nuclear Corp), and SFD Stereotactic Dosimetry Diode Detector (IBA). The depth-dose and profiles data were collected for various field sizes and depths. The dose linearity and dose rate dependency were also evaluated. To evaluate the effects of the preirradiation, the diamond detector which had not been irradiated on the day was set up in the water tank and the response to 100 MU was measured every 20 s. The temperature dependency was tested for the range of 4–60 °C. Angular dependency was evaluated in water phantom by rotating the SCDD. Results: For all radiation types and field sizes, the depth-dose data of the diamond chamber showed identical curve to those of ionization chambers. The profile of the diamond detector was very similar to those of the Edge and SFD detectors, although the 0.125 cm 3 and pinpoint chambers showed averaging effects in the penumbrae region. The temperature dependency was within 0.7% in the range of 4–41°C. A dose of 900 cGy and 1200 cGy were needed to stabilize the chamber to the level within 0.5% and 0.2%, respectively. Conclusion: The type 60019 SCDD detector showed suitable characteristics for depth-dose and profile measurements for wide range of field sizes. However, at least 1000 cGy of pre-irradiation is needed for accurate measurements

  18. Effects of ion beam heating on Raman spectra of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Hulman, Martin; Skakalova, Viera; Krasheninnikov, A. V.; Roth, S.

    2009-01-01

    Free standing films of single-wall carbon nanotubes were irradiated with energetic N + and C 4+ ions. The observed changes in the Raman line shape of the radial breathing mode and the G band of the C 4+ irradiated samples were similar to those found for a thermally annealed sample. We ascribe these changes to thermal desorption of volatile dopants from the initially doped nanotubes. A simple geometry of the experiment allows us to estimate the temperature rise by one-dimensional heat conductance equation. The calculation indicates that irradiation-mediated increase in temperature may account for the observed Raman spectra changes

  19. Ion channel electrophysiology via integrated planar patch-clamp chip with on-demand drug exchange.

    Science.gov (United States)

    Chen, Chang-Yu; Tu, Ting-Yuan; Jong, De-Shien; Wo, Andrew M

    2011-06-01

    Planar patch clamp has revolutionized characterization of ion channel behavior in drug discovery primarily via advancement in high throughput. Lab use of planar technology, however, addresses different requirements and suffers from inflexibility to enable wide range of interrogation via a single cell. This work presents integration of planar patch clamp with microfluidics, achieving multiple solution exchanges for tailor-specific measurement and allowing rapid replacement of the cell-contacting aperture. Studies via endogenously expressed ion channels in HEK 293T cells were commenced to characterize the device. Results reveal the microfluidic concentration generator produces distinct solution/drug combination/concentrations on-demand. Volume-regulated chloride channel and voltage-gated potassium channels in HEK 293T cells immersed in generated solutions under various osmolarities or drug concentrations show unique channel signature under specific condition. Excitation and blockage of ion channels in a single cell was demonstrated via serial solution exchange. Robustness of the reversible bonding and ease of glass substrate replacement were proven via repeated usage of the integrated device. The present approach reveals the capability and flexibility of integrated microfluidic planar patch-clamp system for ion channel assays. Copyright © 2011 Wiley Periodicals, Inc.

  20. Lotus birth, a holistic approach on physiological cord clamping.

    Science.gov (United States)

    Zinsser, Laura A

    2018-04-01

    The positive effects of delayed cord clamping (DCC) has been extensively researched. DCC means: waiting at least one minute after birth before clamping and cutting the cord or till the pulsation has stopped. With physiological clamping and cutting (PCC) the clamping and cutting can happen at the earliest after the pulsation has stopped. With a Lotus birth, no clamping and cutting of the cord is done. A woman called Clair Lotus Day imitated the holistic approach of PCC from an anthropoid ape in 1974. The chimpanzee did not separate the placenta from the newborn. The aim of this case report is to discuss and learn a different approach in the third stage of labour. Three cases of Lotus birth by human beings were observed. All three women gave birth in an out-of-hospital setting and had ambulant postnatal care. The placenta was washed, salted and herbs were put on 2-3h post partum. The placenta was wrapped in something that absorbs the moisture. The salting was repeated with a degreasing frequency depending on moistness of the placenta. On life day six all three Lotus babies experiences a natural separation of the cord. All three Lotus birth cases were unproblematic, no special incidence occurred. One should differentiate between early cord clamping (ECC), delayed cord clamping (DCC) and physiological cord clamping (PCC). Lotus birth might lead to an optimisation of the bonding and attachment. Research is needed in the areas of both PCC and Lotus birth. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  1. Force-controlled patch clamp of beating cardiac cells.

    Science.gov (United States)

    Ossola, Dario; Amarouch, Mohamed-Yassine; Behr, Pascal; Vörös, János; Abriel, Hugues; Zambelli, Tomaso

    2015-03-11

    From its invention in the 1970s, the patch clamp technique is the gold standard in electrophysiology research and drug screening because it is the only tool enabling accurate investigation of voltage-gated ion channels, which are responsible for action potentials. Because of its key role in drug screening, innovation efforts are being made to reduce its complexity toward more automated systems. While some of these new approaches are being adopted in pharmaceutical companies, conventional patch-clamp remains unmatched in fundamental research due to its versatility. Here, we merged the patch clamp and atomic force microscope (AFM) techniques, thus equipping the patch-clamp with the sensitive AFM force control. This was possible using the FluidFM, a force-controlled nanopipette based on microchanneled AFM cantilevers. First, the compatibility of the system with patch-clamp electronics and its ability to record the activity of voltage-gated ion channels in whole-cell configuration was demonstrated with sodium (NaV1.5) channels. Second, we showed the feasibility of simultaneous recording of membrane current and force development during contraction of isolated cardiomyocytes. Force feedback allowed for a gentle and stable contact between AFM tip and cell membrane enabling serial patch clamping and injection without apparent cell damage.

  2. Performance demonstration of a single-frequency optically-pumped cesium beam frequency standard for space applications

    Science.gov (United States)

    Lecomte, S.; Haldimann, M.; Ruffieux, R.; Thomann, P.; Berthoud, P.

    2017-11-01

    Observatoire de Neuchâtel (ON) is developing a compact optically-pumped cesium beam frequency standard in the frame of an ESA-ARTES 5 project. The simplest optical scheme, which is based on a single optical frequency for both preparation and detection processes of atoms, has been chosen to fulfill reliability constraints of space applications. With our laboratory demonstrator operated at 852 nm (D2 line), we have measured a frequency stability of σy=2.74x10-12 τ -1/2, which is compliant with the Galileo requirement. The atomic resonator is fully compliant to be operated with a single diode laser at 894 nm (D1 line). Sensitivity measurements of the clock signal to the microwave power and to the optical pumping power are also presented. Present performance limitations are discussed and further improvements are proposed in order to reach our ultimate frequency stability goal of σy=1x10-12 τ -1/2. The clock driving software is also briefly described.

  3. Cone-beam X-ray phase-contrast tomography for the observation of single cells in whole organs

    International Nuclear Information System (INIS)

    Krenkel, Martin

    2015-01-01

    X-ray imaging enables the nondestructive investigation of interior structures in otherwise opaque samples. In particular the use of computed tomography (CT) allows for arbitrary virtual slices through the object and 3D information about intricate structures can be obtained. However, when it comes to image very small structures like single cells, the classical CT approach is limited by the weak absorption of soft-tissue. The use of phase information, encoded in measureable intensity images by free-space propagation of coherent X-rays, allows a huge increase in contrast, which enables 3D reconstructions at higher resolutions. In this work the application of propagation-based phase-contrast tomography to lung tissue samples is demonstrated in close to in vivo conditions. Reconstructions of the lung structure of whole mice at down to 5 µm resolution are obtained at a selfbuilt CT setup, which is based on a liquid-metal jet X-ray source. To reach even higher resolutions, synchrotron radiation in combination with suitable holographic phase-retrieval algorithms is employed. Due to optimized cone-beam geometry, field of view and resolution can be varied over a wide range of parameters, so that information on different length scales can be achieved, covering several millimeters field of view down to a 3D resolution of 50 nm. Thus, the sub-cellular 3D imaging of single cells embedded in large pieces of tissue is enabled, which paves the way for future biomedical research.

  4. SU-F-T-232: Monthly Quality Assurance in External Beam Radiation Therapy Using a Single System

    Energy Technology Data Exchange (ETDEWEB)

    Ding, K [Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD (United States); Ji, T [Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD (United States); Department of Radiation Oncology, The First Hospital, China Medical University, Shenyang, Liaoning (China); Iordachita, I [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD (United States); Velarde, E; Hyatt, J; Wong, J

    2016-06-15

    Purpose: Monthly quality assurance (QA) is time consuming for external beam radiation therapy, taking as long as 6–8 hours for each machine. It is due to the use and setup of multiple devices for different QA procedures. We have developed a single system with rotational capability for the measurement of both optical light and radiation which significantly reduces the time spent on Monthly QA. Methods: A single system using mirrors, a phosphor screen and a CCD camera is housed on a cylindrical motor so that it can rotate 360 degrees. For monthly QA, the system is placed on the patient couch of the medical accelerator with the plane of the phosphor screen at isocenter for all measurements. For optical QA such as optical distance indicator, room laser and light field, the optical image is collected directly with the camera. For radiation QA such as beam profile, MLC speed, picket-fence test, collimator rotation, table rotation and gantry rotation, a brass build-up plate is attached to the top of the phosphor screen. Two brass plates with islands of different thickness were designed for photon energy and electron energy constancy checks. Flex map, distortion map and uniformity map were developed to calibrate the motor bearing, camera/lens distortion, and the phosphor screen’s measured response across the field. Results: Following the TG142 guidelines for monthly QA with our system, the overall run time is reduced from 6–8 hours to 1.5 hours. Our system’s rotating design allows for quick testing of the gantry radiation isocenter test that is also independent of the sag of the gantry and the EPID. Conclusion: Our system significantly shortens the time needed for monthly QA by unifying the tests with a single system. Future work will be focused on extending the technology to Brachytherapy, IMRT and proton therapy QAs. This work is funded in part by a sponsor research grant from JPLC who owns the Raven technology. John Wong is a co-founder of JPLC.

  5. SU-F-T-232: Monthly Quality Assurance in External Beam Radiation Therapy Using a Single System

    International Nuclear Information System (INIS)

    Ding, K; Ji, T; Iordachita, I; Velarde, E; Hyatt, J; Wong, J

    2016-01-01

    Purpose: Monthly quality assurance (QA) is time consuming for external beam radiation therapy, taking as long as 6–8 hours for each machine. It is due to the use and setup of multiple devices for different QA procedures. We have developed a single system with rotational capability for the measurement of both optical light and radiation which significantly reduces the time spent on Monthly QA. Methods: A single system using mirrors, a phosphor screen and a CCD camera is housed on a cylindrical motor so that it can rotate 360 degrees. For monthly QA, the system is placed on the patient couch of the medical accelerator with the plane of the phosphor screen at isocenter for all measurements. For optical QA such as optical distance indicator, room laser and light field, the optical image is collected directly with the camera. For radiation QA such as beam profile, MLC speed, picket-fence test, collimator rotation, table rotation and gantry rotation, a brass build-up plate is attached to the top of the phosphor screen. Two brass plates with islands of different thickness were designed for photon energy and electron energy constancy checks. Flex map, distortion map and uniformity map were developed to calibrate the motor bearing, camera/lens distortion, and the phosphor screen’s measured response across the field. Results: Following the TG142 guidelines for monthly QA with our system, the overall run time is reduced from 6–8 hours to 1.5 hours. Our system’s rotating design allows for quick testing of the gantry radiation isocenter test that is also independent of the sag of the gantry and the EPID. Conclusion: Our system significantly shortens the time needed for monthly QA by unifying the tests with a single system. Future work will be focused on extending the technology to Brachytherapy, IMRT and proton therapy QAs. This work is funded in part by a sponsor research grant from JPLC who owns the Raven technology. John Wong is a co-founder of JPLC.

  6. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping improves systemic and cerebral oxygenation in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Graeme R Polglase

    Full Text Available As measurement of arterial oxygen saturation (SpO2 is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2 were measured continuously in apnoeic preterm lambs (126±1 day gestation. Positive pressure ventilation was initiated either 1 prior to umbilical cord clamping, or 2 after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  7. Modification of mechanical properties of single crystal aluminum oxide by ion beam induced structural changes

    International Nuclear Information System (INIS)

    Ensinger, W.; Nowak, R.; Horino, Y.; Baba, K.

    1993-01-01

    The mechanical behaviour of ceramics is essentially determined by their surface qualities. As a surface modification technique, ion implantation provides the possibility to modify the mechanical properties of ceramics. Highly energetic ions are implanted into the near-surface region of a material and modify its composition and structure. Ions of aluminum, oxygen, nickel and tantalum were implanted into single-crystal α-aluminum oxide. Three-point bending tests showed that an increase in flexural strength of up to 30% could be obtained after implantation of aluminum and oxygen. Nickel and tantalum ion implantation increased the fracture toughness. Indentation tests with Knoop and Vickers diamonds and comparison of the lengths of the developed radial cracks showed that ion implantation leads to a reaction in cracking. The observed effects are assigned to radiation induced structural changes of the ceramic. Ion bombardment leads to radiation damage and formation of compressive stress. In case of tantalum implantation, the implanted near-surface zone becomes amorphous. These effects make the ceramic more resistant to fracture. (orig.)

  8. Multi-mode excitation of a clamped–clamped microbeam resonator

    KAUST Repository

    Younis, Mohammad I.

    2015-02-18

    We present modeling and simulation of the nonlinear dynamics of a microresonator subjected to two-source electrostatic excitation. The resonator is composed of a clamped–clamped beam excited by a DC voltage load superimposed to two AC voltage loads of different frequencies. One frequency is tuned close to the first natural frequency of the beam and the other is close to the third (second symmetric) natural frequency. A multi-mode Galerkin procedure is applied to extract a reduced-order model, which forms the basis of the numerical simulations. Time history response, Poincare’ sections, Fast Fourier Transforms FFT, and bifurcation diagrams are used to reveal the dynamics of the system. The results indicate complex nonlinear phenomena, which include quasiperiodic motion, torus bifurcations, and modulated chaotic attractors.

  9. Thon rings from amorphous ice and implications of beam-induced Brownian motion in single particle electron cryo-microscopy.

    Science.gov (United States)

    McMullan, G; Vinothkumar, K R; Henderson, R

    2015-11-01

    We have recorded dose-fractionated electron cryo-microscope images of thin films of pure flash-frozen amorphous ice and pre-irradiated amorphous carbon on a Falcon II direct electron detector using 300 keV electrons. We observe Thon rings [1] in both the power spectrum of the summed frames and the sum of power spectra from the individual frames. The Thon rings from amorphous carbon images are always more visible in the power spectrum of the summed frames whereas those of amorphous ice are more visible in the sum of power spectra from the individual frames. This difference indicates that while pre-irradiated carbon behaves like a solid during the exposure, amorphous ice behaves like a fluid with the individual water molecules undergoing beam-induced motion. Using the measured variation in the power spectra amplitude with number of electrons per image we deduce that water molecules are randomly displaced by a mean squared distance of ∼1.1 Å(2) for every incident 300 keV e(-)/Å(2). The induced motion leads to an optimal exposure with 300 keV electrons of 4.0 e(-)/Å(2) per image with which to observe Thon rings centred around the strong 3.7 Å scattering peak from amorphous ice. The beam-induced movement of the water molecules generates pseudo-Brownian motion of embedded macromolecules. The resulting blurring of single particle images contributes an additional term, on top of that from radiation damage, to the minimum achievable B-factor for macromolecular structure determination. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Tumor induction in mice after local irradiation with single doses of either carbon-ion beams or gamma rays.

    Science.gov (United States)

    Ando, Koichi; Koike, Sachiko; Ohmachi, Yasushi; Ando, Yutaka; Kobashi, Gen

    2014-12-01

    To determine the dose-dependent relative biological effectiveness (RBE) for tumor prevalence in mice receiving single localized doses to their right leg of either carbon ions (15, 45 or 75 keV/μm) or 137Cs gamma rays. A total of 1647 female C3H mice were irradiated to their hind legs with a localized dose of either reference gamma rays or 15, 45 or 75 keV/μm carbon-ion beams. Irradiated mice were evaluated for tumors twice a month during their three-year life span, and the dimensions of any tumors found were measured with a caliper. The tumor induction frequency was calculated by Kaplan-Meier analysis. The incidence of tumors from 50 Gy of 45 keV/μm carbon ions was marginally higher than those from 50 Gy of gamma rays. However, 60 Gy of 15 keV/μm carbon ions induced significantly fewer tumors than did gamma rays. RBE values of 0.87 + 0.12, 1.29 + 0.08 or 2.06 + 0.39 for lifetime tumorigenesis were calculated for 15, 45 or 75 keV/μm carbon-ion beams, respectively. Fibrosarcoma predominated, with no Linear Energy Transfer (LET)-dependent differences in the tumor histology. Experiments measuring the late effect of leg skin shrinkage suggested that the carcinogenic damage of 15 keV/μm carbon ions would be less than that of gamma rays. We conclude that patients receiving radiation doses to their normal tissues would face less risk of secondary tumor induction by carbon ions of intermediate LET values compared to equivalent doses of photons.

  11. Increased of the capacity integral bridge with reinforced concrete beams for single span

    Science.gov (United States)

    Setiati, N. Retno

    2017-11-01

    Sinapeul Bridge that was built in 2012 in Sumedang is a bridge type using a full integral system. The prototype of integral bridge with reinforced concrete girder and single span 20 meters until this year had decreased capacity. The bridge was conducted monitoring of strain that occurs in the abutment in 2014. Monitoring results show that based on the data recorded, the maximum strain occurs at the abutment on the location of the integration of the girder of 10.59 x 10-6 tensile stress of 0.25 MPa (smaller than 150 x 10-6) with 3 MPa tensile stress as limit the occurrence of cracks in concrete. Sinapeul bridge abutment with integral system is still in the intact condition. Deflection of the bridge at the time of load test is 1.31 mm. But this time the bridge has decreased exceeded permission deflection (deflection occurred by 40 mm). Besides that, the slab also suffered destruction. One cause of the destruction of the bridge slab is the load factor. It is necessary for required effort to increase the capacity of the integral bridge with retrofitting. Retrofitting method also aims to restore the capacity of the bridge structure due to deterioration. Retrofitting can be done by shortening of the span or using Fibre Reinforced Polymer (FRC). Based on the results obtained by analysis of that method of retrofitting with Fibre Reinforced Polymer (FRC) is more simple and effective. Retrofitting with FRP can increase the capacity of the shear and bending moment becomes 41% of the existing bridge. Retrofitting with FRP method does not change the integral system on the bridge Sinapeul become conventional bridges.

  12. Wavefront measurement of single-mode quantum cascade laser beam for seed application in laser-produced plasma extreme ultraviolet system.

    Science.gov (United States)

    Nowak, Krzysztof M; Ohta, Takeshi; Suganuma, Takashi; Yokotsuka, Toshio; Fujimoto, Junichi; Mizoguchi, Hakaru

    2012-12-01

    Quantum cascade laser (QCL) is a very attractive seed source for a multikilowatt pulsed CO2 lasers applied for driving extreme ultraviolet emitting plasmas. In this Letter, we investigate output beam properties of a QCL designed to address P18 and P20 lines of 10.6 micron band of CO2 molecule. In particular, output beam quality and stability are investigated for the first time. A well-defined linear polarization and a single-mode operation enabled a use of phase retrieval method for full description of QCL output beam. A direct, multi-image numerical phase retrieval technique was developed and successfully applied to the measured intensity patterns of a QCL beam. Very good agreement between the measured and reconstructed beam profiles was observed at distances ranging from QCL aperture to infinity, proving a good understanding of the beam propagation. The results also confirm a high spatial coherence and high stability of the beam parameters, the features expected from an excellent seed source.

  13. Single grain boundary break junction for suspended nanogap electrodes with gapwidth down to 1-2 nm by focused ion beam milling.

    Science.gov (United States)

    Cui, Ajuan; Liu, Zhe; Dong, Huanli; Wang, Yujin; Zhen, Yonggang; Li, Wuxia; Li, Junjie; Gu, Changzhi; Hu, Wenping

    2015-05-20

    Single grain boundary junctions are used for the fabrication of suspended nanogap electrodes with a gapwidth down to 1-2 nm through the break of such junctions by focused ion beam (FIB) milling. With advantages of stability and no debris, such nanogap electrodes are suitable for single molecular electronic device construction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Evaluation of fracture toughness in dental ceramics using indentation and SEVNB (Single Edge V-Notched Beam)-method; Avaliacao da tenacidade a fratura de ceramicas dentarias atraves do metodo de entalhe - SEVNB (Single Edge V-Notched Beam)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, L.A.; Santos, C.; Souza, R.C.; Ribeiro, S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais. Polo Urbo-Industrial; Strecker, K. [Universidade Federal de Sao Joao del-Rei (DME/UFSJ), MG (Brazil). Dept. de Materiais Eletricos; Oberacker, R. [Karlsruhe Univ. (Germany)

    2009-07-01

    In this work, the fracture toughness of different ceramics based on Al{sub 2}O{sub 3} and ZrO{sub 2} were evaluated using, comparatively two methods, Vickers indentation and SEVNB (Single Edge V-Notched Beam) method. Al{sub 2}O{sub 3}, ZrO{sub 2}(3%Y{sub 2}O{sub 3}) micro-particled and ZrO{sub 2}(3%Y{sub 2}O{sub 3}) nanometric, ZrO{sub 2}-Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-ZrO{sub 2} composites were sintered at different temperatures. Samples were characterized by relative density, X-ray diffraction, SEM, and mechanical evaluation by hardness, bending strength and fracture toughness obtained by ickers indentation and SEVNB-method. The results were presented comparing the densification and microstructural results. Furthermore, the advantages and limitations of each method were discussed. (author)

  15. Single mode solid state distributed feedback dye laser fabricated by grey scale electron beam lithography on dye doped SU-8 resist

    DEFF Research Database (Denmark)

    Balslev, Søren; Rasmussen, Torben; Shi, Peixiong

    2005-01-01

    We demonstrate grey scale electron beam lithography on functionalized SU-8 resist for fabrication of single mode solid state dye laser devices. The resist is doped with Rhodamine 6G perchlorate and the lasers are based on a first order Bragg grating distributed feedback resonator. The lasers...

  16. The influence of single and fractionated dose external beam irradiation on injury-induced arterial smooth muscle cell proliferation

    International Nuclear Information System (INIS)

    Schaefer, U.; Micke, O.; Dorszewski, A.; Breithardt, G.; Willich, N.

    1997-01-01

    Purpose/Objective: Restenosis after catheter-based revascularization has been demonstrated to be primarily caused by smooth muscle cell proliferation. This study examined the effects of external beam irradiation on neointimal proliferation after external injury to the central artery of the rabbit ear. Materials and Methods: 40 male New Zealand White rabbits were used in this study. Crush lesions were performed on each ear under general anesthesia and bilateral auricular nerve blockade. A single dose of 12 Gy (n=10), 16 Gy (n=10), or 20 Gy (n=10) and a fractionated dose of 4 x 5 Gy (n=10) gamma radiation was delivered to the left or right central artery of the ear 24 hours after injury; the contralateral central artery served as control. All rabbits were sacrificed after twenty-one days and the central arteries of the ear were fixed for morphometric measurements. Results: Mean (± SD) neointimal area was 0.062 ± 0.005 mm 2 (12 Gy), 0.022 ± 0,005 mm 2 (16 Gy), 0,028 ± 0,006 mm 2 and 0.038 mm 2 ± 0,02 mm 2 (4 x 5 Gy) in irradiated arteries compared with 0,081 ± 0,009 mm 2 in the control group. Mean (±SD) luminal area was 0.049 ± 0.004 mm 2 (12 Gy), 0.059 ± 0.002 mm 2 (16 Gy), 0.072 ± 0,006 mm 2 (20 Gy) and 0.048 mm 2 ± 0,018 mm 2 (4 x 5 Gy) in irradiated arteries compared with 0,043 ± 0,008 mm 2 in the control group. The difference in neointimal and luminal area between control and irradiated arteries was significant (p<0.05) only for the 16 and 20 Gy group compared to control. Conclusion: We conclude that in this model, external beam X-ray irradiation was successful in reducing neointimal proliferation after injury of the central artery of the rabbit ear. The optimal dose seems to be a single dose of 16 Gy - 20 Gy. Only a less prominent effect was noted for a fractionated dose of 4 x 5 Gy. Whether this approach can be used successfully to inhibit restenosis in the clinical setting requires further investigation

  17. A new clamp method for firing bricks | Obeng | Journal of Applied ...

    African Journals Online (AJOL)

    A new clamp method for firing bricks. ... Journal of Applied Science and Technology ... To overcome this operational deficiencies, a new method of firing bricks that uses brick clamp technique that incorporates a clamp wall of 60 cm thickness, a six tier approach of sealing the top of the clamp (by combination of green bricks) ...

  18. External mean flow influence on sound transmission through finite clamped double-wall sandwich panels

    Science.gov (United States)

    Liu, Yu; Catalan, Jean-Cédric

    2017-09-01

    This paper studies the influence of an external mean flow on the sound transmission through finite clamped double-wall sandwich panels lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials and various configurations of coupling the poroelastic layer to the facing plates are considered. The clamped boundary of finite panels are dealt with by the modal superposition theory and the weighted residual (Garlekin) method, leading to a matrix equation solution for the sound transmission loss (STL) through the structure. The theoretical model is validated against existing theories of infinite sandwich panels with and without an external flow. The numerical results of a single incident wave show that the external mean flow has significant effects on the STL which are coupled with the clamped boundary effect dominating in the low-frequency range. The external mean flow also influences considerably the limiting incidence angle of the panel system and the effect of the incidence angle on the STL. However, the influences of the azimuthal angle and the external flow orientation are negligible.

  19. Automated patch clamp on mESC-derived cardiomyocytes for cardiotoxicity prediction.

    Science.gov (United States)

    Stoelzle, Sonja; Haythornthwaite, Alison; Kettenhofen, Ralf; Kolossov, Eugen; Bohlen, Heribert; George, Michael; Brüggemann, Andrea; Fertig, Niels

    2011-09-01

    Cardiovascular side effects are critical in drug development and have frequently led to late-stage project terminations or even drug withdrawal from the market. Physiologically relevant and predictive assays for cardiotoxicity are hence strongly demanded by the pharmaceutical industry. To identify a potential impact of test compounds on ventricular repolarization, typically a variety of ion channels in diverse heterologously expressing cells have to be investigated. Similar to primary cells, in vitro-generated stem cell-derived cardiomyocytes simultaneously express cardiac ion channels. Thus, they more accurately represent the native situation compared with cell lines overexpressing only a single type of ion channel. The aim of this study was to determine if stem cell-derived cardiomyocytes are suited for use in an automated patch clamp system. The authors show recordings of cardiac ion currents as well as action potential recordings in readily available stem cell-derived cardiomyocytes. Besides monitoring inhibitory effects of reference compounds on typical cardiac ion currents, the authors revealed for the first time drug-induced modulation of cardiac action potentials in an automated patch clamp system. The combination of an in vitro cardiac cell model with higher throughput patch clamp screening technology allows for a cost-effective cardiotoxicity prediction in a physiologically relevant cell system.

  20. Robotic multi-well planar patch-clamp for native and primary mammalian cells

    Science.gov (United States)

    Milligan, Carol J; Li, Jing; Sukumar, Piruthivi; Majeed, Yasser; Dallas, Mark L; English, Anne; Emery, Paul; Porter, Karen E; Smith, Andrew M; McFadzean, Ian; Beccano-Kelly, Dayne; Bahnasi, Yahya; Cheong, Alex; Naylor, Jacqueline; Zeng, Fanning; Liu, Xing; Gamper, Nikita; Jiang, Lin-Hua; Pearson, Hugh A; Peers, Chris; Robertson, Brian; Beech, David J

    2009-01-01

    Multi-well robotic planar patch-clamp has become common in drug development and safety programmes because it enables efficient and systematic testing of compounds against ion channels during voltage-clamp. It has not, however, been adopted significantly in other important areas of ion channel research, where conventional patch-clamp remains the favoured method. Here we show the wider potential of the multi-well approach with the capability for efficient intracellular solution exchange, describing protocols and success rates for recording from a range of native and primary mammalian cells derived from blood vessels, arthritic joints, and the immune and central nervous systems. The protocol involves preparing a suspension of single cells to be dispensed robotically into 4-8 microfluidic chambers each containing a glass chip with a small aperture. Under automated control, giga-seals and whole-cell access are achieved followed by pre-programmed routines of voltage paradigms and fast extracellular or intracellular solution exchange. Recording from 48 chambers usually takes 1-6 hr depending on the experimental design and yields 16-33 cell recordings. PMID:19197268

  1. Evaluation of Single File Systems Reciproc, Oneshape, and WaveOne using Cone Beam Computed Tomography -An In Vitro Study.

    Science.gov (United States)

    Dhingra, Annil; Ruhal, Nidhi; Miglani, Anjali

    2015-04-01

    Successful endodontic therapy depends on many factor, one of the most important step in any root canal treatment is root canal preparation. In addition, respecting the original shape of the canal is of the same importance; otherwise, canal aberrations such as transportation will be created. The purpose of this study is to compare and evaluate Reciprocating WaveOne ,Reciproc and Rotary Oneshape Single File Instrumentation System On Cervical Dentin Thickness, Cross Sectional Area and Canal Transportation on First Mandibular Molar Using Cone Beam Computed Tomography. Sixty Mandibular First Molars extracted due to periodontal reason was collected from the Department of Oral and Maxillofacial. Teeth were prepared using one rotary and two reciprocating single file system. Teeth were divided into 3 groups 20 teeth in each group. Pre instrumentation and Post instrumentation scans was done and evaluated for three parameters Canal Transportation, Cervical Dentinal Thickness, Cross-sectional Area. Results were analysed statistically using ANOVA, Post-Hoc Tukey analysis. The change in cross-sectional area after filing showed significant difference at 0mm, 1mm, 2mm and 7mm (pfile system over a distance of 7 mm (starting from 0mm and then evaluation at 1mm, 2mm, 3mm, 5mm and 7mm), the results showed a significant difference among the file systems at various lengths (p= 0.014, 0.046, 0.004, 0.028, 0.005 & 0.029 respectively). Mean value of cervical dentinal removal is maximum at all the levels for oneshape and minimum for waveone showing the better quality of waveone and reciproc over oneshape file system. Significant difference was found at 9mm, 11mm and 12mm between all the three file systems (p<0.001,< 0.001, <0.001). It was concluded that reciprocating motion is better than rotary motion in all the three parameters Canal Transportation, Cross-sectional Area, Cervical Dentinal Thickness.

  2. Single-beam image encryption using spatially separated ciphertexts based on interference principle in the Fresnel domain

    Science.gov (United States)

    Wang, Qu; Guo, Qing; Lei, Liang; Zhou, Jinyun

    2014-12-01

    A new optical security system for image encryption based on optical interference principle and translation property of Fresnel transform (FrT) has been proposed in this article. The algorithm of this proposal is specially designed for single-beam optical decryption and can thoroughly resolve the silhouette problem existing in the previous interference-based scheme. Different from earlier schemes using interference of phase-only masks (POMs), the inverse FrT of primitive image is digitally decomposed into a random POM and a complex field distribution. Information associated with the primitive images can be completely smoothed away by the modulation of this random POM. Through the translation property of FrT, two linear phase-only terms are then used to modulate the obtained random POM and the complex distribution, respectively. Two complex ciphertexts are generated by performing digital inverse FrT again. One cannot recover any visible information of secret image using only one ciphertext. Moreover, to recover the primitive image correctly, the correct ciphertexts must be placed in the certain positions of input plane of decryption system, respectively. As additional keys, position center coordinates of ciphertexts can increase the security strength of this encryption system against brute force attacks greatly. Numerical simulations have been given to verify the performance and feasibility of this proposal. To further enhance the application value of this algorithm, an alternative approach based on Fourier transform has also been discussed briefly.

  3. Determination of a cross-sectional void fraction in a tube bundle using a single beam gamma densitometer

    International Nuclear Information System (INIS)

    Guichard, J.; Mezoul, B.; Peturaud, P.; Thomas, B.

    1991-06-01

    In order to qualify 3-dimensional two-phase flow computer codes modelling average flows in tube bundles, cross-section average void fractions must be measured over sub-channels. On the VATICAN mockup, such void fractions(integrated on the mockup thickness) are determined using a single (narrow) beam gamma densitometer. But to avoid a refined exploration of each measurement mesh, for each test, empirical calibration curves have been developed in a regular mesh of the mockup, in axial flow conditions. These calibration curves, which evaluate the sought cross-sectional value as a function of a chordal void fraction (right in the inter-rod gap) depend only on heat flux density and pressure. The data are consistent with the ARMAND-MASSENA and LELLOUCHE-ZOLOTAR slip correlations, and they are fitted by 3rd degree polynomials, for each heat flux density investigated, with a good accuracy. Unfortunately, preliminary testing and analysis indicate that the use of these calibration curves in subcooled boiling and transverse mixing zones might result in significant uncertainties and errors

  4. Evaluation of a Single-Beam Sonar System to Map Seagrass at Two Sites in Northern Puget Sound, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Lacy, Jessica R.; Finlayson, David P.; Gelfenbaum, Guy

    2008-01-01

    Seagrass at two sites in northern Puget Sound, Possession Point and nearby Browns Bay, was mapped using both a single-beam sonar and underwater video camera. The acoustic and underwater video data were compared to evaluate the accuracy of acoustic estimates of seagrass cover. The accuracy of the acoustic method was calculated for three classifications of seagrass observed in underwater video: bare (no seagrass), patchy seagrass, and continuous seagrass. Acoustic and underwater video methods agreed in 92 percent and 74 percent of observations made in bare and continuous areas, respectively. However, in patchy seagrass, the agreement between acoustic and underwater video was poor (43 percent). The poor agreement between the two methods in areas with patchy seagrass is likely because the two instruments were not precisely colocated. The distribution of seagrass at the two sites differed both in overall percent vegetated and in the distribution of percent cover versus depth. On the basis of acoustic data, seagrass inhabited 0.29 km2 (19 percent of total area) at Possession Point and 0.043 km2 (5 percent of total area) at the Browns Bay study site. The depth distribution at the two sites was markedly different. Whereas the majority of seagrass at Possession Point occurred between -0.5 and -1.5 m MLLW, most seagrass at Browns Bay occurred at a greater depth, between -2.25 and -3.5 m MLLW. Further investigation of the anthropogenic and natural factors causing these differences in distribution is needed.

  5. Raman spectroscopy of individual monocytes reveals that single-beam optical trapping of mononuclear cells occurs by their nucleus

    International Nuclear Information System (INIS)

    Fore, Samantha; Chan, James; Taylor, Douglas; Huser, Thomas

    2011-01-01

    We show that laser tweezers Raman spectroscopy of eukaryotic cells with a significantly larger diameter than the tight focus of a single-beam laser trap leads to optical trapping of the cell by its optically densest part, i.e. typically the cell's nucleus. Raman spectra of individual optically trapped monocytes are compared with location-specific Raman spectra of monocytes adhered to a substrate. When the cell's nucleus is stained with a fluorescent live cell stain, the Raman spectrum of the DNA-specific stain is observed only in the nucleus of individual monocytes. Optically trapped monocytes display the same behavior. We also show that the Raman spectra of individual monocytes exhibit the characteristic Raman signature of cells that have not yet fully differentiated and that individual primary monocytes can be distinguished from transformed monocytes based on their Raman spectra. This work provides further evidence that laser tweezers Raman spectroscopy of individual cells provides meaningful biochemical information in an entirely non-destructive fashion that permits discerning differences between cell types and cellular activity

  6. Strain engineering and one-dimensional organization of metal-insulator domains in single-crystal vanadium dioxide beams.

    Science.gov (United States)

    Cao, J; Ertekin, E; Srinivasan, V; Fan, W; Huang, S; Zheng, H; Yim, J W L; Khanal, D R; Ogletree, D F; Grossman, J C; Wu, J

    2009-11-01

    Correlated electron materials can undergo a variety of phase transitions, including superconductivity, the metal-insulator transition and colossal magnetoresistance. Moreover, multiple physical phases or domains with dimensions of nanometres to micrometres can coexist in these materials at temperatures where a pure phase is expected. Making use of the properties of correlated electron materials in device applications will require the ability to control domain structures and phase transitions in these materials. Lattice strain has been shown to cause the coexistence of metallic and insulating phases in the Mott insulator VO(2). Here, we show that we can nucleate and manipulate ordered arrays of metallic and insulating domains along single-crystal beams of VO(2) by continuously tuning the strain over a wide range of values. The Mott transition between a low-temperature insulating phase and a high-temperature metallic phase usually occurs at 341 K in VO(2), but the active control of strain allows us to reduce this transition temperature to room temperature. In addition to device applications, the ability to control the phase structure of VO(2) with strain could lead to a deeper understanding of the correlated electron materials in general.

  7. SU-F-T-501: Dosimetric Comparison of Single Arc-Per-Beam and Two Arc-Per-Beam VMAT Optimization in the Monaco Treatment Planning System

    Energy Technology Data Exchange (ETDEWEB)

    Kalet, A; Cao, N; Meyer, J; Dempsey, C [University of Washington Medical Center, Seattle, WA (United States); Seattle Cancer Care Alliance, Seattle, WA (United States); Richardson, H [Seattle Cancer Care Alliance, Seattle, WA (United States)

    2016-06-15

    Purpose: The purpose of this study was to evaluate the dosimetric and practical effects of the Monaco treatment planning system “max arcs-per-beam” optimization parameter in pelvic radiotherapy treatments. Methods: A total of 17 previously treated patients were selected for this study with a range of pelvic disease site including prostate(9), bladder(1), uterus(3), rectum(3), and cervix(1). For each patient, two plans were generated, one using a arc-per-beam setting of ‘1’ and another with setting of ‘2’. The setting allows the optimizer to add a gantry direction change, creating multiple arc passes per beam sequence. Volumes and constraints established from the initial clinical treatments were used for planning. All constraints and dose coverage objects were kept the same between plans, and all plans were normalized to 99.7% to ensure 100% of the PTV received 95% of the prescription dose. We evaluated the PTV conformity index, homogeneity index, total monitor units, number of control points, and various dose volume histogram (DVH) points for statistical comparison (alpha=0.05). Results: We found for the 10 complex shaped target volumes (small central volumes with extending bilateral ‘arms’ to cover nodal regions) that the use of 2 arcs-per-beam achieved significantly lower average DVH values for the bladder V20 (p=0.036) and rectum V30 (p=0.001) while still meeting the high dose target constraints. DVH values for the simpler, more spherical PTVs were not found significantly different. Additionally, we found a beam delivery time reduction of approximately 25%. Conclusion: In summary, the dosimetric benefit, while moderate, was improved over a 1 arc-per-beam setting for complex PTVs, and equivalent in other cases. The overall reduced delivery time suggests that the use of multiple arcs-per-beam could lead to reduced patient on table time, increased clinical throughput, and reduced medical physics quality assurance effort.

  8. Vertical dynamics of a single-span beam subjected to moving mass-suspended payload system with variable speeds

    Science.gov (United States)

    He, Wei

    2018-03-01

    This paper presents the vertical dynamics of a simply supported Euler-Bernoulli beam subjected to a moving mass-suspended payload system of variable velocities. A planar theoretical model of the moving mass-suspended payload system of variable speeds is developed based on several assumptions: the rope is massless and rigid, and its length keeps constant; the stiffness of the gantry beam is much greater than the supporting beam, and the gantry beam can be treated as a mass particle traveling along the supporting beam; the supporting beam is assumed as a simply supported Bernoulli-Euler beam. The model can be degenerated to consider two classical cases-the moving mass case and the moving payload case. The proposed model is verified using both numerical and experimental methods. To further investigate the effect of possible influential factors, numerical examples are conducted covering a range of parameters, such as variable speeds (acceleration or deceleration), mass ratios of the payload to the total moving load, and the pendulum lengths. The effect of beam flexibility on swing response of the payload is also investigated. It is shown that the effect of a variable speed is significant for the deflections of the beam. The accelerating movement tends to induce larger beam deflections, while the decelerating movement smaller ones. For accelerating or decelerating movements, the moving mass model may underestimate the deflections of the beam compared with the presented model; while for uniform motion, both the moving mass model and the moving mass-payload model lead to same beam responses. Furthermore, it is observed that the swing response of the payload is not sensitive to the stiffness of the beam for operational cases of a moving crane, thus a simple moving payload model can be employed in the swing control of the payload.

  9. Geometry effect on the behaviour of single and glue-laminated glass fibre reinforced polymer composite sandwich beams loaded in four-point bending

    International Nuclear Information System (INIS)

    Awad, Ziad K.; Aravinthan, Thiru; Manalo, Allan

    2012-01-01

    Highlights: ► Investigated the behaviour of single and glue-laminated GFRP sandwich beam. ► Effect of shear span to depth was a key factor affecting the overall behaviour. ► Comparison with prediction models gave reasonable results in specific regions. ► A failure map was developed to identify the shear and flexural failures of panels. -- Abstract: The research investigated the behaviour of single and glue laminated glass fibre reinforced polymer (GFRP) composite sandwich beams considering different spans and beam cross sections. The composite sandwich beams with different thicknesses (1, 2, 3, 4, and 5 sandwich layers) have been tested in four-point static flexural test with different shear span to depth ratio (a/d). The a/d ratios showed a direct effect on the flexural and shear behaviour. The capacity of the beam decreased with increasing a/d. Various failure modes were observed including core crushing, core shear, and top skin compression failure. The failure mode map developed based on the experimental finding and analytical prediction indicated that the failure mode is affected by the a/d with the number of glue laminated panels.

  10. SU-E-T-556: Monte Carlo Generated Dose Distributions for Orbital Irradiation Using a Single Anterior-Posterior Electron Beam and a Hanging Lens Shield

    International Nuclear Information System (INIS)

    Duwel, D; Lamba, M; Elson, H; Kumar, N

    2015-01-01

    Purpose: Various cancers of the eye are successfully treated with radiotherapy utilizing one anterior-posterior (A/P) beam that encompasses the entire content of the orbit. In such cases, a hanging lens shield can be used to spare dose to the radiosensitive lens of the eye to prevent cataracts. Methods: This research focused on Monte Carlo characterization of dose distributions resulting from a single A-P field to the orbit with a hanging shield in place. Monte Carlo codes were developed which calculated dose distributions for various electron radiation energies, hanging lens shield radii, shield heights above the eye, and beam spoiler configurations. Film dosimetry was used to benchmark the coding to ensure it was calculating relative dose accurately. Results: The Monte Carlo dose calculations indicated that lateral and depth dose profiles are insensitive to changes in shield height and electron beam energy. Dose deposition was sensitive to shield radius and beam spoiler composition and height above the eye. Conclusion: The use of a single A/P electron beam to treat cancers of the eye while maintaining adequate lens sparing is feasible. Shield radius should be customized to have the same radius as the patient’s lens. A beam spoiler should be used if it is desired to substantially dose the eye tissues lying posterior to the lens in the shadow of the lens shield. The compromise between lens sparing and dose to diseased tissues surrounding the lens can be modulated by varying the beam spoiler thickness, spoiler material composition, and spoiler height above the eye. The sparing ratio is a metric that can be used to evaluate the compromise between lens sparing and dose to surrounding tissues. The higher the ratio, the more dose received by the tissues immediately posterior to the lens relative to the dose received by the lens

  11. Image quality and absorbed dose comparison of single- and dual-source cone-beam computed tomography.

    Science.gov (United States)

    Miura, Hideharu; Ozawa, Shuichi; Okazue, Toshiya; Kawakubo, Atsushi; Yamada, Kiyoshi; Nagata, Yasushi

    2018-04-17

    Dual-source cone-beam computed tomography (DCBCT) is currently available in the Vero4DRT image-guided radiotherapy system. We evaluated the image quality and absorbed dose for DCBCT and compared the values with those for single-source CBCT (SCBCT). Image uniformity, Hounsfield unit (HU) linearity, image contrast, and spatial resolution were evaluated using a Catphan phantom. The rotation angle for acquiring SCBCT and DCBCT images is 215° and 115°, respectively. The image uniformity was calculated using measurements obtained at the center and four peripheral positions. The HUs of seven materials inserted into the phantom were measured to evaluate HU linearity and image contrast. The Catphan phantom was scanned with a conventional CT scanner to measure the reference HU for each material. The spatial resolution was calculated using high-resolution pattern modules. Image quality was analyzed using ImageJ software ver. 1.49. The absorbed dose was measured using a 0.6-cm 3 ionization chamber with a 16-cm-diameter cylindrical phantom, at the center and four peripheral positions of the phantom, and calculated using weighted cone-beam CT dose index (CBCTDI w ). Compared with that of SCBCT, the image uniformity of DCBCT was slightly reduced. A strong linear correlation existed between the measured HU for DCBCT and the reference HU, although the linear regression slope was different from that of the reference HU. DCBCT had poorer image contrast than did SCBCT, particularly with a high-contrast material. There was no significant difference between the spatial resolutions of SCBCT and DCBCT. The absorbed dose for DCBCT was higher than that for SCBCT, because in DCBCT, the two x-ray projections overlap between 45° and 70°. We found that the image quality was poorer and the absorbed dose was higher for DCBCT than for SCBCT in the Vero4DRT. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of

  12. Natural Vibration Analysis of Clamped Rectangular Orthotropic Plates

    Science.gov (United States)

    dalaei, m.; kerr, a. d.

    The natural vibrations of clamped rectangular orthotropic plates are analyzed using the extended Kantorovich method. The developed iterative scheme converges very rapidly to the final result. The obtained natural frequencies are evaluated for a square plate made of Kevlar 49 Epoxy and the obtained results are compared with those published by Kanazawa and Kawai, and by Leissa. The agreement was found to be very close. As there are no exact analytical solutions for clamped rectangular plates, the generated closed form expression for the natural modes, and the corresponding natural frequencies, are very suitable for use in engineering analyses.

  13. Improved DNA clamps by stacking to adjacent nucleobases

    DEFF Research Database (Denmark)

    Fatthalla, M.I.; Pedersen, Erik Bjerregaard

    2012-01-01

    Three or four aromatic rings interconnected by acetylene bridges form a stiff conjugated system with sufficient conformational freedom to make it useful to link together the two strands of a DNA clamp. Upon targeting a ssDNA, the conformational flexibility allows better stacking of the linker...... to the underlying non-planar base triplet in the formed triplex. This type of triplexes has a substantially higher thermal melting temperature which can be further improved by inserting locked nucleic acids (LNAs) in the Hoogsteen part of the clamp. An extremely high sensitivity to mismatches is observed...

  14. Experimental determination of optimal clamping torque for AB-PEM Fuel cell

    Directory of Open Access Journals (Sweden)

    Noor Ul Hassan

    2016-04-01

    Full Text Available Polymer electrolyte Membrane (PEM fuel cell is an electrochemical device producing electricity by the reaction of hydrogen and oxygen without combustion. PEM fuel cell stack is provided with an appropriate clamping torque to prevent leakage of reactant gases and to minimize the contact resistance between gas diffusion media (GDL and bipolar plates. GDL porous structure and gas permeability is directly affected by the compaction pressure which, consequently, drastically change the fuel cell performance. Various efforts were made to determine the optimal compaction pressure and pressure distributions through simulations and experimentation. Lower compaction pressure results in increase of contact resistance and also chances of leakage. On the other hand, higher compaction pressure decreases the contact resistance but also narrows down the diffusion path for mass transfer from gas channels to the catalyst layers, consequently, lowering cell performance. The optimal cell performance is related to the gasket thickness and compression pressure on GDL. Every stack has a unique assembly pressure due to differences in fuel cell components material and stack design. Therefore, there is still need to determine the optimal torque value for getting the optimal cell performance. This study has been carried out in continuation of deve­lopment of Air breathing PEM fuel cell for small Unmanned Aerial Vehicle (UAV application. Compaction pressure at minimum contact resistance was determined and clamping torque value was calcu­la­ted accordingly. Single cell performance tests were performed at five different clamping torque values i.e 0.5, 1.0, 1.5, 2.0 and 2.5 N m, for achieving optimal cell per­formance. Clamping pressure distribution tests were also performed at these torque values to verify uniform pressure distribution at optimal torque value. Experimental and theoretical results were compared for making inferences about optimal cell perfor­man­ce. A

  15. Global and local characteristics of an autogenous single pass electron beam weld in thick gage UNS S41500 steel

    Energy Technology Data Exchange (ETDEWEB)

    Sarafan, S., E-mail: Sheida.Sarafan.1@ens.etsmtl.ca [École de Technologie Supérieure, Montréal, Québec, Canada H3C 1K3 (Canada); National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Wanjara, P., E-mail: priti.wanjara@nrc-cnrc.gc.ca [National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Gholipour, J., E-mail: Javad.gholipour@nrc-cnrc.gc.ca [National Research Council Canada, Aerospace, Montréal, Québec, Canada H3T 2B2 (Canada); Champliaud, H., E-mail: henri.champliaud@etsmtl.ca [École de Technologie Supérieure, Montréal, Québec, Canada H3C 1K3 (Canada)

    2016-06-01

    Electron beam welding of UNS S41500, a low carbon martensitic stainless steel utilized in hydroelectric turbine manufacturing, was investigated by applying a single pass autogenous process to penetrate a section thickness of 72 mm without preheating. In the as-welded and post-weld heat treated conditions, the evolution in microhardness and microstructure across the weldments, as well as the global and local tensile properties, were evaluated. In the as-welded condition, assessment of the microhardness and the associated microstructure across the welds led to the identification of six regions, including the fusion zone, four heat affected zones and the base metal; each of these regions consisted of different phase constituents, such as tempered martensite, untempered martensite, delta ferrite and retained austenite. Post-weld heat treatment, undertaken to temper the untempered martensite in the as-welded microstructure, was effective in homogenizing the hardness across the weldment. The mechanical response of the welds, determined through tensile testing at room temperature with an automated non-contact three-dimensional deformation measurement system, indicated that the global tensile properties in the as-welded and post-weld heat treated conditions met the acceptance criteria in the ASME Section IX standard. Also, evaluation of the local tensile properties in the fusion and heat affected zones of the as-welded samples allowed a more comprehensive understanding of the strength and ductility associated with the different microstructures in the “composite” nature of the weldment. Fractographic analysis demonstrated dimpled features on the tensile fracture surfaces and failure was associated with debonding between the martensitic matrix and the secondary phases (such as delta ferrite and retained austenite) that resulted in the formation, growth and coalescence of voids into a macroscale crack.

  16. Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

    KAUST Repository

    Jaber, Nizar

    2016-01-06

    © 2016 IOP Publishing Ltd. In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped-clamped microbeam resonators. The concept is based on using partial electrodes with shapes that induce strong excitation of the mode of interest. The devices are fabricated using polyimide as a structural layer coated with nickel from the top and chrome and gold layers from the bottom. Experimentally, frequency sweeps with different electro-dynamical loading conditions are shown to demonstrate the excitation of the higher order modes of vibration. Using a half electrode, the second mode is excited with high amplitude of vibration compared with almost zero response using the full electrode. Also, using a two-third electrode configuration is shown to amplify the third mode resonance amplitude compared with the full electrode under the same electrical loading conditions. An analytical model is developed based on the Euler-Bernollui beam model and the Galerkin method to simulate the device response. Good agreement between the simulation results and the experimental data is reported.

  17. A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, Katsuki [Kyoto Univ. (Japan)

    2009-01-01

    Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for vμ → vx oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (vμN → μ-+) and coherent pion production interacting with the entire nucleus (vμA → μ-+), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, vμ 12C → μ-12+, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 1020 protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 1020 protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio

  18. 21 CFR 882.5175 - Carotid artery clamp.

    Science.gov (United States)

    2010-04-01

    ... (the principal artery in the neck that supplies blood to the brain) and has a removable adjusting mechanism that protrudes through the skin of the patient's neck. The clamp is used to occlude the patient's... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  19. Estimates for lower order eigenvalues of a clamped plate problem

    OpenAIRE

    Cheng, Qing-Ming; Huang, Guangyue; Wei, Guoxin

    2009-01-01

    For a bounded domain $\\Omega$ in a complete Riemannian manifold $M^n$, we study estimates for lower order eigenvalues of a clamped plate problem. We obtain universal inequalities for lower order eigenvalues. We would like to remark that our results are sharp.

  20. 33 CFR 183.532 - Clips, straps, and hose clamps.

    Science.gov (United States)

    2010-07-01

    ... resistant material; and (2) Not cut or abrade the fuel line. (b) If tested in accordance with the fire test under § 183.590, a hose clamp installed on a fuel line system requiring metallic fuel lines or “USCG... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.532 Clips...

  1. Euglycemic clamp insulin sensitivity and longitudinal systolic blood pressure

    DEFF Research Database (Denmark)

    Petrie, John R; Malik, Muhammad Omar; Balkau, Beverley

    2013-01-01

    and Cardiovascular disease (RISC) study, we measured insulin sensitivity (M/I) using the euglycemic clamp technique in 1073 healthy European adults (587 women, 486 men) aged 30 to 60 years followed up 3 years later. Systolic BP (SBP) at baseline was higher in insulin-resistant women (ie, those in the low sex...

  2. Dosimetric comparison of single-beam multi-arc and 2-beam multi-arc VMAT optimization in the Monaco treatment planning system

    Energy Technology Data Exchange (ETDEWEB)

    Kalet, Alan M., E-mail: amkalet@uw.edu [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States); Richardson, Hannah L.; Nikolaisen, Darrin A. [Seattle Cancer Care Alliance, Seattle, Washington (United States); Cao, Ning [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States); Lavilla, Myra A. [Seattle Cancer Care Alliance, Seattle, Washington (United States); Dempsey, Claire; Meyer, Juergen; Koh, Wui-Jin; Russell, Kenneth J. [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States)

    2017-07-01

    The purpose of this study was to evaluate the dosimetric and practical effects of the Monaco treatment planning system “max arcs-per-beam” optimization parameter in pelvic radiotherapy treatments. We selected for this study a total of 17 previously treated patients with a range of pelvic disease sites including prostate (9), bladder (1), uterus (3), rectum (3), and cervix (1). For each patient, 2 plans were generated, one using an arc-per-beam setting of “1” and another with an arc-per-beam setting of “2” using the volumes and constraints established from the initial clinical treatments. All constraints and dose coverage objects were kept the same between plans, and all plans were normalized to 99.7% to ensure 100% of the planning target volume (PTV) received 95% of the prescription dose. Plans were evaluated for PTV conformity, homogeneity, number of monitor units, number of control points, and overall plan acceptability. Treatment delivery time, patient-specific quality assurance procedures, and the impact on clinical workflow were also assessed. We found that for complex-shaped target volumes (small central volumes with extending arms to cover nodal regions), the use of 2 arc-per-beam (2APB) parameter setting achieved significantly lower average dose-volume histogram values for the rectum V{sub 20} (p = 0.0012) and bladder V{sub 30} (p = 0.0036) while meeting the high dose target constraints. For simple PTV shapes, we found reduced monitor units (13.47%, p = 0.0009) and control points (8.77%, p = 0.0004) using 2APB planning. In addition, we found a beam delivery time reduction of approximately 25%. In summary, the dosimetric benefit, although moderate, was improved over a 1APB setting for complex PTV, and equivalent in other cases. The overall reduced delivery time suggests that the use of mulitple arcs per beam could lead to reduced patient-on-table time, increased clinical throughput, and reduced medical physics quality assurance

  3. Fast synchrotron and FEL beam monitors based on single-crystal diamond detectors and InGaAs/InAlAs quantum well devices

    Science.gov (United States)

    Antonelli, M.; Di Fraia, M.; Carrato, S.; Cautero, G.; Menk, R. H.; Jark, W. H.; Ganbold, T.; Biasiol, G.; Callegari, C.; Coreno, M.; De Sio, A.; Pace, E.

    2013-12-01

    Simultaneous photon-beam position and intensity monitoring is becoming of increasing importance for new-generation synchrotron radiation sources and free-electron lasers (FEL). Thus, novel concepts of beam diagnostics are required in order to keep such beams under control. From this perspective diamond is a promising material for the production of semitransparent in situ photon beam monitors, which can withstand the high dose rates occurring in such radiation facilities. Here, we report on the development of freestanding, single-crystal chemical-vapor-deposited diamond detectors with segmented electrodes. Due to their direct, low-energy band gap, InGaAs quantum well devices operated at room temperature may also be used as fast detectors for photons ranging from visible to X-ray. These features are valuable in low-energy and time-resolved FEL applications. In particular, a novel segmented InGaAs/InAlAs device has been developed and will be discussed. Dedicated measurements carried out on both these devices at the Elettra Synchrotron show their capability to monitor the position and the intensity of the photon beam with bunch-by-bunch temporal performances. Furthermore, preliminary tests have been performed on diamond detectors at the Fermi FEL, extracting quantitative intensity and position information for 100-fs-wide FEL pulses with a photon energy of 28.8 eV.

  4. Beam-Beam Effects

    International Nuclear Information System (INIS)

    Herr, W; Pieloni, T

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities

  5. Characterization of heterologously expressed transporter genes by patch- and voltage-clamp methods: Application to cyclic nucleotide-dependent responses

    KAUST Repository

    Lemtiri-Chlieh, Fouad; Ali, Rashid Ayesha

    2013-01-01

    The application of patch- and voltage-clamp methods to study ion transport can be limited by many hurdles: the size of the cells to be patched and/or stabbed, the subcellular localization of the molecule of interest, and its density of expression that could be too low even in their own native environment. Functional expression of genes using recombinant DNA technology not only overcomes those hurdles but also affords additional and elegant investigations such as single-point mutation studies and subunit associations/regulations. In this chapter, we give a step-by-step description of two electrophysiological methods, patch clamp and two-electrode voltage clamp (TEVC), that are routinely used in combination with heterologous gene expression to assist researchers interested in the identification and characterization of ion transporters. We describe how to (1) obtain and maintain the cells suitable for the use with each of the above-mentioned methods (i.e., HEK-293 cells and yeast spheroplasts to use with the patch-clamp methodology and Xenopus laevis oocytes with TEVC), (2) transfect/inject them with the gene of interest, and (3) record ion transport activities. © Springer Science+Business Media New York 2013.

  6. Characterization of heterologously expressed transporter genes by patch- and voltage-clamp methods: Application to cyclic nucleotide-dependent responses

    KAUST Repository

    Lemtiri-Chlieh, Fouad

    2013-09-03

    The application of patch- and voltage-clamp methods to study ion transport can be limited by many hurdles: the size of the cells to be patched and/or stabbed, the subcellular localization of the molecule of interest, and its density of expression that could be too low even in their own native environment. Functional expression of genes using recombinant DNA technology not only overcomes those hurdles but also affords additional and elegant investigations such as single-point mutation studies and subunit associations/regulations. In this chapter, we give a step-by-step description of two electrophysiological methods, patch clamp and two-electrode voltage clamp (TEVC), that are routinely used in combination with heterologous gene expression to assist researchers interested in the identification and characterization of ion transporters. We describe how to (1) obtain and maintain the cells suitable for the use with each of the above-mentioned methods (i.e., HEK-293 cells and yeast spheroplasts to use with the patch-clamp methodology and Xenopus laevis oocytes with TEVC), (2) transfect/inject them with the gene of interest, and (3) record ion transport activities. © Springer Science+Business Media New York 2013.

  7. Performance of a low cost single beam echosounder : in situ trials in a shallow water coral reef habitat with verification by video

    OpenAIRE

    Betanzos, A.; Martín, H.A.; Valle, S.; Tizol, R.; Schneider, P.; Hernández, J.L.; Brehmer, Patrice; Linares, E.O.; Guillard, J.; Hermand, J.P.

    2015-01-01

    In a context of potential overexploitation of fisheries resources in the Sabana-Camagüey Archipelago (Cuba), the Cuban national authorities have expressed the need to collect more in situ information on fish of commercial interest in spawning areas. A newly developed low cost single-beam scientific echosounder has been recently acquired by the Cuban Fisheries Research Centre (CIP). In this work, we provide first results of a comparative analysis carried out in the Sabana-Camagüey ...

  8. Model-based seafloor characterization employing multi-beam angular backscatter data - A comparative study with dual-frequency single beam

    Digital Repository Service at National Institute of Oceanography (India)

    Haris, K.; Chakraborty, B.; De, C.; Desai, R.G.P.; Fernandes, W.A.

    developed by Jackson et al., 3 has been extensively applied to this approach. 4-6 In this work, characterization of seafloor sediments is achieved by employing a MB system (Simrad EM 1002) operable at 95 kHz. Here, the seafloor parameters are estimated... pre-formed beams data were acquired during two cruises using the EM1002 echo-sounding system installed onboard CRV Sagar Sukti (cruises: SASU-108 and 134). 13,14 Besides calculating the angular backscatter strengths using the MB system, the modeled...

  9. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-file Systems.

    Science.gov (United States)

    Prabhakar, Attiguppe R; Yavagal, Chandrashekar; Dixit, Kratika; Naik, Saraswathi V

    2016-01-01

    Primary root canals are considered to be most challenging due to their complex anatomy. "Wave one" and "one shape" are single-file systems with reciprocating and rotary motion respectively. The aim of this study was to evaluate and compare dentin thickness, centering ability, canal transportation, and instrumentation time of wave one and one shape files in primary root canals using a cone beam computed tomographic (CBCT) analysis. This is an experimental, in vitro study comparing the two groups. A total of 24 extracted human primary teeth with minimum 7 mm root length were included in the study. Cone beam computed tomographic images were taken before and after the instrumentation for each group. Dentin thickness, centering ability, canal transportation, and instrumentation times were evaluated for each group. A significant difference was found in instrumentation time and canal transportation measures between the two groups. Wave one showed less canal transportation as compared with one shape, and the mean instrumentation time of wave one was significantly less than one shape. Reciprocating single-file systems was found to be faster with much less procedural errors and can hence be recommended for shaping the root canals of primary teeth. How to cite this article: Prabhakar AR, Yavagal C, Dixit K, Naik SV. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-File Systems. Int J Clin Pediatr Dent 2016;9(1):45-49.

  10. Note: Decoupling design for high frequency piezoelectric ultrasonic transducers with their clamping connections

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F. J., E-mail: wangfujun@tju.edu.cn; Liang, C. M.; Tian, Y. L.; Zhao, X. Y.; Zhang, D. W. [Tianjin Key Laboratory of Equipment Design and Manufacturing Technology, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhang, H. J. [Tianjin Key Laboratory of Modern Mechatronics Equipment Technology, School of Mechanical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2015-12-15

    This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.

  11. Fabrication of Si-based planar type patch clamp biosensor using silicon on insulator substrate

    International Nuclear Information System (INIS)

    Zhang, Z.L.; Asano, T.; Uno, H.; Tero, R.; Suzui, M.; Nakao, S.; Kaito, T.; Shibasaki, K.; Tominaga, M.; Utsumi, Y.; Gao, Y.L.; Urisu, T.

    2008-01-01

    The aim of this paper is to fabricate the planar type patch clamp ion-channel biosensor, which is suitable for the high throughput screening, using silicon-on-insulator (SOI) substrate. The micropore with 1.2 μm diameter is formed through the top Si layer and the SiO 2 box layer of the SOI substrate by focused ion beam (FIB). Then the substrate is assembled into the microfluidic circuit. The human embryonic kidney 293 (HEK-293) cell transfected with transient receptor potential vanilloid type 1 (TRPV1) is positioned on the micropore and the whole-cell configuration is formed by the suction. Capsaicin is added to the extracellular solution as a ligand molecule, and the channel current showing the desensitization unique to TRPV1 is measured successfully

  12. Fabrication of Si-based planar type patch clamp biosensor using silicon on insulator substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.L.; Asano, T. [Graduate University for Advanced Studies, Myodaiji, Okazaki, 444-8585 (Japan); Uno, H. [Institute for Molecular Science, Myodaiji, Okazaki, 444-8585 (Japan); Tero, R. [Graduate University for Advanced Studies, Myodaiji, Okazaki, 444-8585 (Japan); Institute for Molecular Science, Myodaiji, Okazaki, 444-8585 (Japan); Suzui, M.; Nakao, S. [Institute for Molecular Science, Myodaiji, Okazaki, 444-8585 (Japan); Kaito, T. [SII NanoTechnology Inc., 36-1, Takenoshita, Oyama-cho, Sunto-gun, Shizuoka, 410-1393 (Japan); Shibasaki, K.; Tominaga, M. [Okazaki Institute for Integrative Bioscience, 5-1, Higashiyama, Myodaiji, Okazaki, 444-8787 (Japan); Utsumi, Y. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2, Koto, Kamigori, Ako-gun, Hyogo, 678-1205 (Japan); Gao, Y.L. [Department of Physics and Astronomy, Rochester University, Rochester, New York 14627 (United States); Urisu, T. [Graduate University for Advanced Studies, Myodaiji, Okazaki, 444-8585 (Japan); Institute for Molecular Science, Myodaiji, Okazaki, 444-8585 (Japan)], E-mail: urisu@ims.ac.jp

    2008-03-03

    The aim of this paper is to fabricate the planar type patch clamp ion-channel biosensor, which is suitable for the high throughput screening, using silicon-on-insulator (SOI) substrate. The micropore with 1.2 {mu}m diameter is formed through the top Si layer and the SiO{sub 2} box layer of the SOI substrate by focused ion beam (FIB). Then the substrate is assembled into the microfluidic circuit. The human embryonic kidney 293 (HEK-293) cell transfected with transient receptor potential vanilloid type 1 (TRPV1) is positioned on the micropore and the whole-cell configuration is formed by the suction. Capsaicin is added to the extracellular solution as a ligand molecule, and the channel current showing the desensitization unique to TRPV1 is measured successfully.

  13. Patch-Clamp Recording from Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Improving Action Potential Characteristics through Dynamic Clamp

    Science.gov (United States)

    Veerman, Christiaan C.; Zegers, Jan G.; Mengarelli, Isabella; Bezzina, Connie R.

    2017-01-01

    Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) hold great promise for studying inherited cardiac arrhythmias and developing drug therapies to treat such arrhythmias. Unfortunately, until now, action potential (AP) measurements in hiPSC-CMs have been hampered by the virtual absence of the inward rectifier potassium current (IK1) in hiPSC-CMs, resulting in spontaneous activity and altered function of various depolarising and repolarising membrane currents. We assessed whether AP measurements in “ventricular-like” and “atrial-like” hiPSC-CMs could be improved through a simple, highly reproducible dynamic clamp approach to provide these cells with a substantial IK1 (computed in real time according to the actual membrane potential and injected through the patch-clamp pipette). APs were measured at 1 Hz using perforated patch-clamp methodology, both in control cells and in cells treated with all-trans retinoic acid (RA) during the differentiation process to increase the number of cells with atrial-like APs. RA-treated hiPSC-CMs displayed shorter APs than control hiPSC-CMs and this phenotype became more prominent upon addition of synthetic IK1 through dynamic clamp. Furthermore, the variability of several AP parameters decreased upon IK1 injection. Computer simulations with models of ventricular-like and atrial-like hiPSC-CMs demonstrated the importance of selecting an appropriate synthetic IK1. In conclusion, the dynamic clamp-based approach of IK1 injection has broad applicability for detailed AP measurements in hiPSC-CMs. PMID:28867785

  14. Electron beam based transversal profile measurements of intense ion beams

    International Nuclear Information System (INIS)

    El Moussati, Said

    2014-01-01

    application range of the EBI diagnostic method and to benchmark the theoretical model. To achieve this goal a code has been developed in the programming language Python. Different charge distributions were considered and the simulation results have been compared with the theoretical model. The numerical investigations have shown a very good agreement with the theoretical model for deflection angles up to 20 mrad. This value defines the limit for the applicability of the theoretical model. Moreover, the magnetic field of the ion beam has also been taken into acount in the simulations. The results show that at high ion beam currents - starting at about 1 A - the electrons experience a non-negligible displacement along the ion beam axis, which has to be taken into consideration in experiments with intense heavy ion beams. The electrons suffer practically the same displacement under the influence of the magnetic field, regardless of their offset. At an offset of 10 mm the deviation from the shift at the ion beam axis is less than 3 %. For the experimental investigations of the EBI diagnostic method an offline experiment had been set up at the HHT experimental area at GSI in Darmstadt. The Coulomb field of the ion beam had been simulated by electrostatically charged wires. In case of a single wire, the experimental results are in good agreement with the theoretical model for deflection angles up to 20 mrad. This confirms the results of the numerical studies. To simulate the field within an ion beam, several wires have been clamped parallel to each other within a plane perpendicular to the electron beam. The electrons thus could pass through the spaces between the wires. The results of this experiments have quantitatively confirmed the prediction of the theoretical model that the derivative of the deflection angle with respect to the offset is proportional to the charge distribution in the cross section of the ion beam. Quantitatively, however, deviations from the theoretical model

  15. Four- year thyroidectomy procedures: Ligasure Vs. clamp & tie

    Directory of Open Access Journals (Sweden)

    Pazoki AR

    2010-01-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: The electrothermal bipolar vessel sealing system is an adjunct to the hemostatic technique, which has been successfully used in many abdominal operation, recently made available to thyroid surgery. The purpose of this was compare the outcomes of new hemostatic technique with traditional method of clamp and tie."n"nMethods: In this retrospective cross-sectional study has been done in surgery's wards of Milad & Rasul- Akram hospitals in Tehran, Iran. During three- year period between 2005-2008 all patients with different kind of pathology that need operation were assessed. Time duration of surgery and hospital stay and post surgery complication in two group, ligasure (n=45 and clamp & tie (n=145 were compared with each others."n"nResults: No difference was seen between two groups in time duration of surgery. Significant difference was seen in hospital stay and complications of surgery. Time of operation in Ligasure group was 132/22 minute and in clamp and tie group was 130/10 minute. There was found significant difference in duration of hospital stay and postoperative complication. Hypocalcemia were seen in two and 24 cases in Ligasure and Clamp & Tie group, respectively (p<0.05. Hospital stay was 2

  16. Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

    KAUST Repository

    Jaber, Nizar; Ramini, Abdallah; Carreno, Armando Arpys Arevalo; Younis, Mohammad I.

    2016-01-01

    © 2016 IOP Publishing Ltd. In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped-clamped microbeam resonators. The concept is based on using

  17. Isolated PWM DC-AC SICAM with an active capacitive voltage clamp[Pulse Density Modulated; Pulse Width Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2004-03-15

    In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)

  18. Active energy recovery clamping circuit to improve the performance of power converters

    Science.gov (United States)

    Whitaker, Bret; Barkley, Adam

    2017-05-09

    A regenerative clamping circuit for a power converter using clamping diodes to transfer charge to a clamping capacitor and a regenerative converter to transfer charge out of the clamping capacitor back to the power supply input connection. The regenerative converter uses a switch connected to the midpoint of a series connected inductor and capacitor. The ends of the inductor and capacitor series are connected across the terminals of the power supply to be in parallel with the power supply.

  19. Gigaseal formation in patch clamping with applications of nanotechnology

    CERN Document Server

    Malboubi, Majid

    2014-01-01

    This book presents an investigation of gigaseal formation using micro/nanotechnology. The aims of the book are twofold. First, it explains the mechanisms of gigaseal formation using the latest discoveries. Second, it provides practical techniques for frequent formation of high resistance seals. The formation of a high-resistance electrical seal, also known as a gigaseal, between a cell membrane and a glass micropipette tip is essential in patch-clamp experiments. Even though four decades have passed since the introduction of the patch-clamping technique by Neher and Sakmann, gigaseal formation remains an obstacle in developing the high-throughput ion channel screening systems required by the pharmaceutical industry. Here the authors share their latest methods for achieving gigaseal formation and describe techniques that are highly desirable at both research and industrial levels. Nanotechnology has been found to be a powerful tool for studying and modifying glass micropipettes and in tackling the problem of g...

  20. Launch and capture of a single particle in a pulse-laser-assisted dual-beam fiber-optic trap

    Science.gov (United States)

    Fu, Zhenhai; She, Xuan; Li, Nan; Hu, Huizhu

    2018-06-01

    The rapid loading and manipulation of microspheres in optical trap is important for its applications in optomechanics and precision force sensing. We investigate the microsphere behavior under coaction of a dual-beam fiber-optic trap and a pulse laser beam, which reveals a launched microsphere can be effectively captured in a spatial region. A suitable order of pulse duration for launch is derived according to the calculated detachment energy threshold of pulse laser. Furthermore, we illustrate the effect of structural parameters on the launching process, including the spot size of pulse laser, the vertical displacement of beam waist and the initial position of microsphere. Our result will be instructive in the optimal design of the pulse-laser-assisted optical tweezers for controllable loading mechanism of optical trap.

  1. Analysis of the Pallet Clamping Conditions in Work Positioning

    OpenAIRE

    L. A. Kolesnikov

    2016-01-01

    Pallets of automatic transfer lines serve as the technological and work-transfer equipment. However, their design is based on the general principles of designing machine accessories. Calculation of the basic design parameters of work based on their functioning features is fairly relevant.In pallet transfer movement over work positioning there is a mismatch between axes of the basic bushing of a pallet and the clamping locks of positioning. The paper identifies the factors influencing it, and ...

  2. Constant-frequency, clamped-mode resonant converters

    Science.gov (United States)

    Tsai, Fu-Sheng; Materu, Peter; Lee, Fred C.

    1987-01-01

    Two novel clamped-mode resonant converters are proposed which operate at a constant frequency while retaining many desired features of conventional series- and parallel-resonant converters. State-plane analysis techniques are used to identify all possible operating modes and define their mode boundaries. Control-to-output characteristics are derived that specify the regions for natural and forced commutation. The predicted operating modes are verified using a prototype circuit.

  3. Voltage Balancing Control of Diode-Clamped Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    ŞCHIOP Adrian

    2013-10-01

    Full Text Available In this paper is developed a control scheme for mono-phase diode clamped inverter to achieve balancing voltages on inverter capacitors. First, it develops a control scheme without taking into account the need to balance voltage on two capacitors. It examines the effects on the output voltage inverter, and then it realizes two control schemes that will balance the voltages. The simulations of control schemes were performed in OrCAD Pspice.

  4. File list: Oth.ALL.50.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.Clamp.AllCell dm3 TFs and others Clamp All cell types SRX159172,SRX15917...0,SRX159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.50.Clamp.AllCell.bed ...

  5. File list: Oth.CeL.50.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.50.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.50.Clamp.AllCell.bed ...

  6. File list: Oth.CeL.05.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.05.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.05.Clamp.AllCell.bed ...

  7. The Single Particle Theory of Backward-Wave Amplifications Based on Electron Cyclotron Maser with a Rectilinear Beam

    International Nuclear Information System (INIS)

    Jiang Lina; Wang Hongyu; Sun Peng

    2014-01-01

    The theory of slow backward-wave amplifications is developed based on electron cyclotron maser (ECM) mechanism employing an initially rectilinear beam. A nonlinear evolution equation is derived to describe the electron energy. Numerical calculations show that the saturated interaction efficiency in this system may exceed 20%, and the saturated interaction length spans 3–6 centimeters. The distinctive interaction mechanism is promising for the design of compact backward microwave amplification devices. Numerical studies are also presented for the slow-wave ECM efficiency with inclusion of Gaussian beam electron velocity spread. It is shown that the velocity spread reduces the interaction efficiency. (basic plasma phenomena)

  8. Role of the Checkpoint Clamp in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Mihoko Kai

    2013-01-01

    Full Text Available DNA damage occurs during DNA replication, spontaneous chemical reactions, and assaults by external or metabolism-derived agents. Therefore, all living cells must constantly contend with DNA damage. Cells protect themselves from these genotoxic stresses by activating the DNA damage checkpoint and DNA repair pathways. Coordination of these pathways requires tight regulation in order to prevent genomic instability. The checkpoint clamp complex consists of Rad9, Rad1 and Hus1 proteins, and is often called the 9-1-1 complex. This PCNA (proliferating cell nuclear antigen-like donut-shaped protein complex is a checkpoint sensor protein that is recruited to DNA damage sites during the early stage of the response, and is required for checkpoint activation. As PCNA is required for multiple pathways of DNA metabolism, the checkpoint clamp has also been implicated in direct roles in DNA repair, as well as in coordination of the pathways. Here we discuss roles of the checkpoint clamp in DNA damage response (DDR.

  9. A search for neutral, heavy particles decaying to a neutriNO1and a single photon at the SPS wide-band neutrino beam

    CERN Document Server

    Steele, D M

    1996-01-01

    A search is performed for single, isolated photons from X 0 decay, where X 0 represents either a neutrino excited state or an unknown, neutral, massive particle produced in a rare pi+ decay along the neutrino beam line as hypothesized by the KARMEN Collaboration[1] as a possible solution to their anomalous time spectra for pi+ -> u+ + vu. The analysis is performed using data from the NOMAD (WA96) experiment in the wide-band vu beam using the SPS accelerator situated at the European Center for Nuclear Research near Geneva, Switzerland. Out of a flux of vu resulting from 6.13 x 10*18 protons on target, seven events pass all cuts. The relative abundance of these events is entirely consistent with those expected from neutrino interactions in the detector. Upper limits are set at 90% condence level for the production rate of this particle as a function of its lifetime.

  10. In situ beam analysis of radiation damage kinetics in MgTiO3 single crystals at 170-470 K

    International Nuclear Information System (INIS)

    Yu, Ning; Mitchell, J.N.; Sickafus, K.E.; Nastasi, M.

    1995-01-01

    Radiation damage kinetics in synthetic MgTiO 3 (geikielite) single crystals have been studied using the in situ ion beam facility at Los Alamos National Laboratory. The geikielite samples were irradiated at temperatures of 170, 300, and 470 K with 400 keV xenon ions and the radiation damage was sequentially measured with Rutherford backscattering using a 2 MeV He ion beam along a channeling direction. Threshold doses of I and 5x l0 15 Xe/cm 2 were determined for the crystalline-to-amorphous transformation induced by Xe ion irradiation at 170 and 300 K, respectively. However, geikielite retained its crystallinity up to a dose of 2.5xl0 16 Xe/cm 2 at the irradiation temperature of 470 K. This study has shown that MgTiO 3 , which has a corundum derivative structure, is another radiation resistant material that has the potential for use in radiation environments

  11. Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

    Directory of Open Access Journals (Sweden)

    Juliano Fujioka Mologni

    2010-04-01

    Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

  12. Single-step fabrication of stressed waveguides with tubular depressed-cladding in phosphate glasses using ultrafast vortex laser beams

    Directory of Open Access Journals (Sweden)

    Cheng Guanghua

    2013-11-01

    Full Text Available We report on the fabrication of the stressed optical waveguide with tubular depressed-refractive-index cladding in phosphate glasses by use of femtosecond vortex beam. Strained regions were emerged in domains surrounding the tubular track. Waveguiding occurs mainly within the tube induced by femtosecond laser.

  13. TH-C-BRD-05: Reducing Proton Beam Range Uncertainty with Patient-Specific CT HU to RSP Calibrations Based On Single-Detector Proton Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Doolan, P [University College London, London (United Kingdom); Massachusetts General Hospital, Boston, MA (United States); Sharp, G; Testa, M; Lu, H-M [Massachusetts General Hospital, Boston, MA (United States); Bentefour, E [Ion Beam Applications (IBA), Louvain la Neuve (Belgium); Royle, G [University College London, London (United Kingdom)

    2014-06-15

    Purpose: Beam range uncertainty in proton treatment comes primarily from converting the patient's X-ray CT (xCT) dataset to relative stopping power (RSP). Current practices use a single curve for this conversion, produced by a stoichiometric calibration based on tissue composition data for average, healthy, adult humans, but not for the individual in question. Proton radiographs produce water-equivalent path length (WEPL) maps, dependent on the RSP of tissues within the specific patient. This work investigates the use of such WEPL maps to optimize patient-specific calibration curves for reducing beam range uncertainty. Methods: The optimization procedure works on the principle of minimizing the difference between the known WEPL map, obtained from a proton radiograph, and a digitally-reconstructed WEPL map (DRWM) through an RSP dataset, by altering the calibration curve that is used to convert the xCT into an RSP dataset. DRWMs were produced with Plastimatch, an in-house developed software, and an optimization procedure was implemented in Matlab. Tests were made on a range of systems including simulated datasets with computed WEPL maps and phantoms (anthropomorphic and real biological tissue) with WEPL maps measured by single detector proton radiography. Results: For the simulated datasets, the optimizer showed excellent results. It was able to either completely eradicate or significantly reduce the root-mean-square-error (RMSE) in the WEPL for the homogeneous phantoms (to zero for individual materials or from 1.5% to 0.2% for the simultaneous optimization of multiple materials). For the heterogeneous phantom the RMSE was reduced from 1.9% to 0.3%. Conclusion: An optimization procedure has been designed to produce patient-specific calibration curves. Test results on a range of systems with different complexities and sizes have been promising for accurate beam range control in patients. This project was funded equally by the Engineering and Physical Sciences

  14. Correlation of open cell-attached and excised patch clamp techniques.

    Science.gov (United States)

    Filipovic, D; Hayslett, J P

    1995-11-01

    The excised patch clamp configuration provides a unique technique for some types of single channel analyses, but maintenance of stable, long-lasting preparations may be confounded by rundown and/or rapid loss of seal. Studies were performed on the amiloride-sensitive Na+ channel, located on the apical surface of A6 cells, to determine whether the nystatin-induced open cell-attached patch could serve as an alternative configuration. Compared to excised inside-out patches, stable preparations were achieved more readily with the open cell-attached patch (9% vs. 56% of attempts). In both preparations, the current voltage (I-V) relation was linear, current amplitudes were equal at opposite equivalent clamped voltages, and Erev was zero in symmetrical Na+ solutions, indicating similar Na+ activities on the cytosolic and external surfaces of the patch. Moreover, there was no evidence that nystatin altered channel activity in the patch because slope conductance (3-4pS) and Erev (75 mV), when the bath was perfused with a high K:low Na solution (ENa = 80 mV), were nearly equal in both patch configurations. Our results therefore indicate that the nystatin-induced open cell-attached patch can serve as an alternative approach to the excised inside-out patch when experiments require modulation of univalent ions in the cytosol.

  15. A direct proofreader-clamp interaction stabilizes the Pol III replicase in the polymerization mode

    KAUST Repository

    Jergic, Slobodan; Horan, Nicholas P.; Elshenawy, Mohamed; Mason, Claire E.; Urathamakul, Thitima; Ozawa, Kiyoshi; Robinson, Andrew J.; Goudsmits, Joris M H; Wang, Yao; Pan, Xuefeng; Beck, Jennifer L.; Van Oijen, Antoine M.; Huber, Thomas L.; Hamdan, Samir; Dixon, Nicholas E.

    2013-01-01

    Processive DNA synthesis by the αÉ"θ core of the Escherichia coli Pol III replicase requires it to be bound to the β 2 clamp via a site in the α polymerase subunit. How the É" proofreading exonuclease subunit influences DNA synthesis by α was not previously understood. In this work, bulk assays of DNA replication were used to uncover a non-proofreading activity of É". Combination of mutagenesis with biophysical studies and single-molecule leading-strand replication assays traced this activity to a novel β-binding site in É" that, in conjunction with the site in α, maintains a closed state of the αÉ"θ-β 2 replicase in the polymerization mode of DNA synthesis. The É"-β interaction, selected during evolution to be weak and thus suited for transient disruption to enable access of alternate polymerases and other clamp binding proteins, therefore makes an important contribution to the network of protein-protein interactions that finely tune stability of the replicase on the DNA template in its various conformational states. © 2013 European Molecular Biology Organization.

  16. A direct proofreader-clamp interaction stabilizes the Pol III replicase in the polymerization mode

    KAUST Repository

    Jergic, Slobodan

    2013-02-22

    Processive DNA synthesis by the αÉ"θ core of the Escherichia coli Pol III replicase requires it to be bound to the β 2 clamp via a site in the α polymerase subunit. How the É" proofreading exonuclease subunit influences DNA synthesis by α was not previously understood. In this work, bulk assays of DNA replication were used to uncover a non-proofreading activity of É". Combination of mutagenesis with biophysical studies and single-molecule leading-strand replication assays traced this activity to a novel β-binding site in É" that, in conjunction with the site in α, maintains a closed state of the αÉ"θ-β 2 replicase in the polymerization mode of DNA synthesis. The É"-β interaction, selected during evolution to be weak and thus suited for transient disruption to enable access of alternate polymerases and other clamp binding proteins, therefore makes an important contribution to the network of protein-protein interactions that finely tune stability of the replicase on the DNA template in its various conformational states. © 2013 European Molecular Biology Organization.

  17. Laser microsurgery of higher plant cell walls permits patch-clamp access

    International Nuclear Information System (INIS)

    Henriksen, G.H.; Taylor, A.R.; Brownlee, C.; Assmann, S.M.

    1996-01-01

    Plasma membranes of guard cells in epidermal peels of Vicia faba and Commelina communis can be made accessible to a patch-clamp pipet by removing a small portion (1-3 micrometer in diameter) of the guard cell wall using a microbeam of ultraviolet light generated by a nitrogen laser. Using this laser microsurgical technique, we have measured channel activity across plasma membranes of V. faba guard cells in both cell-attached and isolated patch configurations. Measurements made in the inside-out patch configuration revealed two distinct K+-selective channels. Major advantages of the laser microsurgical technique include the avoidance of enzymatic protoplast isolation, the ability to study cell types that have been difficult to isolate as protoplasts or for which enzymatic isolation protocols result in protoplasts not amenable to patch-clamp studies, the maintenance of positional information in single-channel measurements, reduced disruption of cell-wall-mediated signaling pathways, and the ability to investigate intercellular signaling through studies of cells remaining situated within tissue

  18. A Single MEMS Resonator for Reconfigurable Multifunctional Logic Gates

    KAUST Repository

    Tella, Sherif Adekunle

    2018-04-30

    Despite recent efforts toward true electromechanical resonator-based computing, achieving complex logics functions through cascading micro resonators has been deterred by challenges involved in their interconnections and the large required array of resonators. In this work we present a single micro electromechanical resonator with two outputs that enables the realization of multifunctional logic gates as well as other complex logic operations. As examples, we demonstrate the realization of the fundamental 2-bit logic gates of OR, XOR, AND, NOR, and a half adder. The device is based on a compound resonator consisting of a clamped-guided electrostatically actuated arch beam that is attached to another resonant beam from the side, which serves as an additional actuation electrode for the arch. The structure is also provided with an additional electrothermal tuning capability. The logic operations are based on the linear frequency modulations of the arch resonator and side microbeam. The device is compatible with CMOS fabrication process and works at room temperature

  19. A Single MEMS Resonator for Reconfigurable Multifunctional Logic Gates

    KAUST Repository

    Tella, Sherif Adekunle; Alcheikh, Nouha; Younis, Mohammad I.

    2018-01-01

    Despite recent efforts toward true electromechanical resonator-based computing, achieving complex logics functions through cascading micro resonators has been deterred by challenges involved in their interconnections and the large required array of resonators. In this work we present a single micro electromechanical resonator with two outputs that enables the realization of multifunctional logic gates as well as other complex logic operations. As examples, we demonstrate the realization of the fundamental 2-bit logic gates of OR, XOR, AND, NOR, and a half adder. The device is based on a compound resonator consisting of a clamped-guided electrostatically actuated arch beam that is attached to another resonant beam from the side, which serves as an additional actuation electrode for the arch. The structure is also provided with an additional electrothermal tuning capability. The logic operations are based on the linear frequency modulations of the arch resonator and side microbeam. The device is compatible with CMOS fabrication process and works at room temperature

  20. Shear and foundation effects on crack root rotation and mode-mixity in moment- and force-loaded single cantilever beam sandwich specimen

    DEFF Research Database (Denmark)

    Saseendran, Vishnu; Carlsson, Leif A.; Berggreen, Christian

    2017-01-01

    Foundation effects play a crucial role in sandwich fracture specimens with a soft core. Accurate estimation of deformationcharacteristics at the crack front is vital in understanding compliance, energy release rate and mode-mixity infracture test specimens. Beam on elastic foundation analysis...... modulus is proposed that closely agrees with the numerical compliance and energy release rate results forall cases considered. An analytical expression for crack root rotation of the loaded upper face sheet provides consistentresults for both loading configurations. For the force-loaded single cantilever...

  1. Analysis of sub-bandgap losses in TiO2 coating deposited via single and dual ion beam deposition

    Czech Academy of Sciences Publication Activity Database

    Žídek, Karel; Hlubuček, Jiří; Horodyská, Petra; Budasz, Jiří; Václavík, Jan

    2017-01-01

    Roč. 626, March (2017), s. 60-65 ISSN 0040-6090 R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Ion beam deposition * Titanium dioxide * Optical coating * Sub-bandgap losses * Urbach tail Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.879, year: 2016 http://www.sciencedirect.com/science/article/pii/S0040609017301256

  2. New force replica exchange method and protein folding pathways probed by force-clamp technique.

    Science.gov (United States)

    Kouza, Maksim; Hu, Chin-Kun; Li, Mai Suan

    2008-01-28

    We have developed a new extended replica exchange method to study thermodynamics of a system in the presence of external force. Our idea is based on the exchange between different force replicas to accelerate the equilibrium process. This new approach was applied to obtain the force-temperature phase diagram and other thermodynamical quantities of the three-domain ubiquitin. Using the C(alpha)-Go model and the Langevin dynamics, we have shown that the refolding pathways of single ubiquitin depend on which terminus is fixed. If the N end is fixed then the folding pathways are different compared to the case when both termini are free, but fixing the C terminal does not change them. Surprisingly, we have found that the anchoring terminal does not affect the pathways of individual secondary structures of three-domain ubiquitin, indicating the important role of the multidomain construction. Therefore, force-clamp experiments, in which one end of a protein is kept fixed, can probe the refolding pathways of a single free-end ubiquitin if one uses either the polyubiquitin or a single domain with the C terminus anchored. However, it is shown that anchoring one end does not affect refolding pathways of the titin domain I27, and the force-clamp spectroscopy is always capable to predict folding sequencing of this protein. We have obtained the reasonable estimate for unfolding barrier of ubiquitin, using the microscopic theory for the dependence of unfolding time on the external force. The linkage between residue Lys48 and the C terminal of ubiquitin is found to have the dramatic effect on the location of the transition state along the end-to-end distance reaction coordinate, but the multidomain construction leaves the transition state almost unchanged. We have found that the maximum force in the force-extension profile from constant velocity force pulling simulations depends on temperature nonlinearly. However, for some narrow temperature interval this dependence becomes

  3. Evaluation influence of machining parameters on shape form errors in turning of machine parts clamped in the chuck with adaptive jaws

    Directory of Open Access Journals (Sweden)

    I.V. Lutsiv

    2017-12-01

    Full Text Available The paper deals with the derivation problem of the dependence of machine part geometric form deviation in cross section area on clamping diameter as well as cutting speed, feed and cutting depth in semi finish machining. The analysis of single factor circular deviation dependences on machining conditions values is performed. Using the special software application package the laboratory conditions experiment results are analyzed. The dispersion analysis including options for main linear and quadratic effects evaluation is given and the simplification model of experiment results is obtained. It presents the evaluation empiric dependence of cutting conditions and clamping diameter influence on shape error forming (dynamic error. It is found that to obtain the necessary form accuracy in machining with lathe chuck equipped with the adaptive clamping jaws it is desirable to control the most statistically significant factors that actually are the cutting depth and feed.

  4. Dynamics of a clamped–clamped microbeam resonator considering fabrication imperfections

    KAUST Repository

    Bataineh, Ahmad M.

    2014-10-18

    We present an investigation into the static and dynamic behavior of an electrostatically actuated clamped–clamped polysilicon microbeam resonator accounting for its fabrication imperfections, which are commonly encountered in similar microstructures. These are mainly because of the initial deformation of the beam due to stress gradient and its flexible anchors. First, we show experimental data of the microbeam when driven electrically by varying the amplitude and frequency of the voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Theoretical investigation is then conducted to model the microbeam, and hence, interpret the experimental data. We solve the Eigen value problem governing the natural frequencies analytically. We then utilize a Galerkin-based procedure to derive a reduced order model, which is then used to simulate both the static and dynamic responses. To achieve good matching between theory and experiment, we show that the exact profile of the deformed beam needs to be utilized in the reduced order model, as measured from the optical profiler, combined with a shooting technique simulation, which is capable of tracing the resonant frequency branches under very-low damping conditions.

  5. The Dynamics of a Doubly Clamped Microbeam Near the Primary Resonance: Experimental and Analytical Investigation

    KAUST Repository

    Masri, Karim M.

    2016-01-20

    We present experimental and analytical investigation of the dynamics of a doubly clamped microbeam near its primary resonance. The microbeam is excited electrostatically by an electrode on the first half of the beam. These microbeams are fabricated using polyimide as structural layer coated with nickel from top and chromium and gold layers from bottom. A noise signal is applied to experimentally detect the natural frequencies. Then, frequency sweep tests are generated for various values of DC bias revealing hardening, transition, and softening behavior of the microbeam. We report for the first time the transition from lower stable state, to unstable state, and then to large stable state experimentally. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. Shooting method is used to find the periodic motion and is utilized to generate frequency response curves. The curves show good agreement with the experimental results with hardening behavior at lower DC voltage then softening at higher voltage loads and dynamic pull-in. © Copyright 2015 by ASME.

  6. Comparative evaluation of effect of rotary and reciprocating single-file systems on pericervical dentin: A cone-beam computed tomography study.

    Science.gov (United States)

    Zinge, Priyanka Ramdas; Patil, Jayaprakash

    2017-01-01

    The aim of this study is to evaluate and compare the effect of one shape, Neolix rotary single-file systems and WaveOne, Reciproc reciprocating single-file systems on pericervical dentin (PCD) using cone-beam computed tomography (CBCT). A total of 40 freshly extracted mandibular premolars were collected and divided into two groups, namely, Group A - Rotary: A 1 - Neolix and A 2 - OneShape and Group B - Reciprocating: B 1 - WaveOne and B 2 - Reciproc. Preoperative scans of each were taken followed by conventional access cavity preparation and working length determination with 10-k file. Instrumentation of the canal was done according to the respective file system, and postinstrumentation CBCT scans of teeth were obtained. 90 μm thick slices were obtained 4 mm apical and coronal to the cementoenamel junction. The PCD thickness was calculated as the shortest distance from the canal outline to the closest adjacent root surface, which was measured in four surfaces, i.e., facial, lingual, mesial, and distal for all the groups in the two obtained scans. There was no significant difference found between rotary single-file systems and reciprocating single-file systems in their effect on PCD, but in Group B 2 , there was most significant loss of tooth structure in the mesial, lingual, and distal surface ( P file system removes more PCD as compared to other experimental groups, whereas Neolix single file system had the least effect on PCD.

  7. Clamped seismic metamaterials: ultra-low frequency stop bands

    International Nuclear Information System (INIS)

    Achaoui, Y; Enoch, S; Guenneau, S; Antonakakis, T; Brûlé, S; Craster, R V

    2017-01-01

    The regularity of earthquakes, their destructive power, and the nuisance of ground vibration in urban environments, all motivate designs of defence structures to lessen the impact of seismic and ground vibration waves on buildings. Low frequency waves, in the range 1–10 Hz for earthquakes and up to a few tens of Hz for vibrations generated by human activities, cause a large amount of damage, or inconvenience; depending on the geological conditions they can travel considerable distances and may match the resonant fundamental frequency of buildings. The ultimate aim of any seismic metamaterial, or any other seismic shield, is to protect over this entire range of frequencies; the long wavelengths involved, and low frequency, have meant this has been unachievable to date. Notably this is scalable and the effects also hold for smaller devices in ultrasonics. There are three approaches to obtaining shielding effects: bragg scattering, locally resonant sub-wavelength inclusions and zero-frequency stop-band media. The former two have been explored, but the latter has not and is examined here. Elastic flexural waves, applicable in the mechanical vibrations of thin elastic plates, can be designed to have a broad zero-frequency stop-band using a periodic array of very small clamped circles. Inspired by this experimental and theoretical observation, all be it in a situation far removed from seismic waves, we demonstrate that it is possible to achieve elastic surface (Rayleigh) wave reflectors at very large wavelengths in structured soils modelled as a fully elastic layer periodically clamped to bedrock. We identify zero frequency stop-bands that only exist in the limit of columns of concrete clamped at their base to the bedrock. In a realistic configuration of a sedimentary basin 15 m deep we observe a zero frequency stop-band covering a broad frequency range of 0–30 Hz. (paper)

  8. [Time of cord clamping and neonatal complications, a prospective study].

    Science.gov (United States)

    Rincón, D; Foguet, A; Rojas, M; Segarra, E; Sacristán, E; Teixidor, R; Ortega, A

    2014-09-01

    To assess the effects of early or late clamping of the umbilical cord in term newborns, assessing the levels of hemoglobin, hematocrit, and ferritin, and their correlation with some of the complications. A prospective study of healthy newborns at term or born by dystotic or eutocic delivery in our hospital between May 2009 until May 2010. Patients were assigned according to the time of clamping, group 1 (<60 seconds), group 2 (1 to<2 minutes), and group 3 (2 to 3 minutes). Laboratory tests were performed at birth and at 48 hours of life, assessing the levels of hemoglobin, hematocrit, ferritin, and bilirubin. The risk of polycythemia, respiratory distress syndrome, neonatal phototherapy or admission to the Intensive Care Unit and the hospital stay, were evaluated. A total of 242 patients were included: group 1 (g1=80), group 2 (g2=31) y group 3 (g3=131). The background maternal and neonatal characteristics were similar in all sets. The first test showed significant differences in ferritin levels in those infants with delayed clamping (g1: 111 mg/dl, g2: 125 mg/dl, g3: 173 mg/dl; p<0.01). In the second analysis the values of hemoglobin (g1: 17.3 g/dl, g2: 18.9 g/dl, g3: 19.2 g/dl; p<0.01), hematocrit (g1: 53.4%, g2: 58%, g3: 59%; p<0.01) and ferritin (g1: 254 mg/dl, g2: 254.7 mg/dl, g3: 313 mg/dl; p = 0.008) were statistically higher in this group. As regards complications, a significant increase was observed in the number of cases of polycythemia symptoms in group 3. The late cord clamping is associated with an increase in hematocrit, hemoglobin and ferritin at 48 hours of life, as well as an increased risk of polycythemia present with symptoms. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  9. A new configuration for multilevel converters with diode clamped topology

    DEFF Research Database (Denmark)

    Nami, A.; Zare, F.; Ledwich, G.

    2008-01-01

    Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial...... of load changes which can avoid neutral point balancing problem in such converters. In addition, the presented topology is suitable for renewable energy systems to boost the low rectified output-voltage. In order to verify the proposed topology, steady state analysis, modelling and simulations are carried...

  10. Five-level Z-source diode-clamped inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This study proposes a five-level Z-source diode-clamped inverter designed with two intermediate Z-source networks connected between the dc input sources and rear-end inverter circuitry. By partially shorting the Z-source networks, new operating states not previously reported for two-level Z......-source inverter are introduced here for operating the proposed inverter with voltage buck–boost energy conversion ability and five-level phase voltage switching. These characteristic features are in fact always ensured at the inverter terminal output by simply adopting a properly designed carrier modulation...

  11. Potassium Chloride Versus Voltage Clamp Contractures in Ventricular Muscle

    Science.gov (United States)

    Morad, M.; Reeck, S.; Rao, M.

    1981-01-01

    In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.

  12. Relative excitation functions for singly-excited and core-excited levels of S V--S IX populated by the beam-foil interaction

    International Nuclear Information System (INIS)

    Moenke, D.; Bengtsson, P.; Engstroem, L.; Hutton, R.; Jupen, C.; Kirm, M.; Westerlind, M.

    1994-01-01

    We have investigated the relative excitation functions for low-lying singly excited and low-lying core-excited levels in S V (S 4+ ) to S IX (S 8+ ) after beam-foil excitation using ions in the energy range 2--10 MeV. The spectral line intensities have been normalized to the same number of particles at each ion energy and corrections for the level lifetimes have been made. The overall accuracy of the measured relative excitation function at each energy and charge state is estimated to be better than 2%. A comparison of the relative excitation functions for singly excited and core-excited lines shows a difference in S VII, but not in S VI

  13. Experimental demonstration of all-optical weak magnetic field detection using beam-deflection of single-mode fiber coated with cobalt-doped nickel ferrite nanoparticles.

    Science.gov (United States)

    Pradhan, Somarpita; Chaudhuri, Partha Roy

    2015-07-10

    We experimentally demonstrate single-mode optical-fiber-beam-deflection configuration for weak magnetic-field-detection using an optimized (low coercive-field) composition of cobalt-doped nickel ferrite nanoparticles. Devising a fiber-double-slit type experiment, we measure the surrounding magnetic field through precisely measuring interference-fringe yielding a minimum detectable field ∼100  mT and we procure magnetization data of the sample that fairly predicts SQUID measurement. To improve sensitivity, we incorporate etched single-mode fiber in double-slit arrangement and recorded a minimum detectable field, ∼30  mT. To further improve, we redefine the experiment as modulating fiber-to-fiber light-transmission and demonstrate the minimum field as 2.0 mT. The device will be uniquely suited for electrical or otherwise hazardous environments.

  14. Development of a silicon microstrip detector with single photon sensitivity for fast dynamic diffraction experiments at a synchrotron radiation beam

    Science.gov (United States)

    Arakcheev, A.; Aulchenko, V.; Kudashkin, D.; Shekhtman, L.; Tolochko, B.; Zhulanov, V.

    2017-06-01

    Time-resolved experiments on the diffraction of synchrotron radiation (SR) from crystalline materials provide information on the evolution of a material structure after a heat, electron beam or plasma interaction with a sample under study. Changes in the material structure happen within a microsecond scale and a detector with corresponding parameters is needed. The SR channel 8 of the VEPP-4M storage ring provides radiation from the 7-pole wiggler that allows to reach several tens photons within one μs from a tungsten crystal for the most intensive diffraction peak. In order to perform experiments that allow to measure the evolution of tungsten crystalline structure under the impact of powerful laser beam, a new detector is developed, that can provide information about the distribution of a scattered SR flux in space and its evolution in time at a microsecond scale. The detector is based on the silicon p-in-n microstrip sensor with DC-coupled metal strips. The sensor contains 1024 30 mm long strips with a 50 μm pitch. 64 strips are bonded to the front-end electronics based on APC128 ASICs. The APC128 ASIC contains 128 channels that consist of a low noise integrator with 32 analogue memory cells each. The integrator equivalent noise charge is about 2000 electrons and thus the signal from individual photons with energy above 40 keV can be observed. The signal can be stored at the analogue memory with 10 MHz rate. The first measurements with the beam scattered from a tungsten crystal with energy near 60 keV demonstrated the capability of this prototype to observe the spatial distribution of the photon flux with the intensity from below one photon per channel up to 0~10 photons per channel with a frame rate from 10 kHz up to 1 MHz.

  15. Multiocular image sensor with on-chip beam-splitter and inner meta-micro-lens for single-main-lens stereo camera.

    Science.gov (United States)

    Koyama, Shinzo; Onozawa, Kazutoshi; Tanaka, Keisuke; Saito, Shigeru; Kourkouss, Sahim Mohamed; Kato, Yoshihisa

    2016-08-08

    We developed multiocular 1/3-inch 2.75-μm-pixel-size 2.1M- pixel image sensors by co-design of both on-chip beam-splitter and 100-nm-width 800-nm-depth patterned inner meta-micro-lens for single-main-lens stereo camera systems. A camera with the multiocular image sensor can capture horizontally one-dimensional light filed by both the on-chip beam-splitter horizontally dividing ray according to incident angle, and the inner meta-micro-lens collecting the divided ray into pixel with small optical loss. Cross-talks between adjacent light field images of a fabricated binocular image sensor and of a quad-ocular image sensor are as low as 6% and 7% respectively. With the selection of two images from one-dimensional light filed images, a selective baseline for stereo vision is realized to view close objects with single-main-lens. In addition, by adding multiple light field images with different ratios, baseline distance can be tuned within an aperture of a main lens. We suggest the electrically selective or tunable baseline stereo vision to reduce 3D fatigue of viewers.

  16. Bunch by bunch beam monitoring in 3rd and 4th generation light sources by means of single crystal diamond detectors and quantum well devices

    Science.gov (United States)

    Antonelli, M.; Di Fraia, M.; Tallaire, A.; Achard, J.; Carrato, S.; Menk, R. H.; Cautero, G.; Giuressi, D.; Jark, W. H.; Biasiol, G.; Ganbold, T.; Oliver, K.; Callegari, C.; Coreno, M.; De Sio, A.; Pace, E.

    2012-10-01

    New generation Synchrotron Radiation (SR) sources and Free Electron Lasers (FEL) require novel concepts of beam diagnostics to keep photon beams under surveillance, asking for simultaneous position and intensity monitoring. To deal with high power load and short time pulses provided by these sources, novel materials and methods are needed for the next generation BPMs. Diamond is a promising material for the production of semitransparent in situ X-ray BPMs withstanding the high dose rates of SR rings and high energy FELs. We report on the development of freestanding, single crystal CVD diamond detectors. Performances in both low and radio frequency SR beam monitoring are presented. For the former, sensitivity deviation was found to be approximately 2%; a 0.05% relative precision in the intensity measurements and a 0.1-μm precision in the position encoding have been estimated. For the latter, single-shot characterizations revealed sub-nanosecond rise-times and spatial precisions below 6 μm, which allowed bunch-by-bunch monitoring in multi-bunch operation. Preliminary measurements at the Fermi FEL have been performed with this detector, extracting quantitative intensity and position information for FEL pulses (~ 100 fs, energy 12 ÷ 60 eV), with a long-term spatial precision of about 85 μm results on FEL radiation damages are also reported. Due to their direct, low-energy band gap, InGaAs quantum well devices too may be used as fast detectors for photons ranging from visible to X-ray. Results are reported which show the capability of a novel InGaAs/InAlAs device to detect intensity and position of 100-fs-wide laser pulses.

  17. Full characterization of laser-accelerated ion beams using Faraday cup, silicon carbide, and single-crystal diamond detectors

    Czech Academy of Sciences Publication Activity Database

    Margarone, Daniele; Krása, Josef; Giuffrida, L.; Picciotto, A.; Torrisi, L.; Nowak, T.; Musumeci, P.; Velyhan, Andriy; Prokůpek, Jan; Láska, Leoš; Mocek, Tomáš; Ullschmied, Jiří; Rus, Bedřich

    2011-01-01

    Roč. 109, č. 10 (2011), "103302-1"-"103302-8" ISSN 0021-8979 R&D Projects: GA ČR(CZ) GAP205/11/1165; GA MŠk(CZ) 7E09092 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : aluminium * chemical sensors * diamond * electrostatics * iodine * ion beams * thin films * lasers * time of flight spectrometers Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.168, year: 2011 http://jap.aip.org/ resource /1/japiau/v109/i10/p103302_s1

  18. Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

    Science.gov (United States)

    Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

    2017-06-01

    Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m-1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread--an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.

  19. Small Molecules for Early Endosome-Specific Patch Clamping.

    Science.gov (United States)

    Chen, Cheng-Chang; Butz, Elisabeth S; Chao, Yu-Kai; Grishchuk, Yulia; Becker, Lars; Heller, Stefan; Slaugenhaupt, Susan A; Biel, Martin; Wahl-Schott, Christian; Grimm, Christian

    2017-07-20

    To resolve the subcellular distribution of endolysosomal ion channels, we have established a novel experimental approach to selectively patch clamp Rab5 positive early endosomes (EE) versus Rab7/LAMP1-positive late endosomes/lysosomes (LE/LY). To functionally characterize ion channels in endolysosomal membranes with the patch-clamp technique, it is important to develop techniques to selectively enlarge the respective organelles. We found here that two small molecules, wortmannin and latrunculin B, enlarge Rab5-positive EE when combined but not Rab7-, LAMP1-, or Rab11 (RE)-positive vesicles. The two compounds act rapidly, specifically, and are readily applicable in contrast to genetic approaches or previously used compounds such as vacuolin, which enlarges EE, RE, and LE/LY. We apply this approach here to measure currents mediated by TRPML channels, in particular TRPML3, which we found to be functionally active in both EE and LE/LY in overexpressing cells as well as in endogenously expressing CD11b+ lung-tissue macrophages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The human dynamic clamp as a paradigm for social interaction.

    Science.gov (United States)

    Dumas, Guillaume; de Guzman, Gonzalo C; Tognoli, Emmanuelle; Kelso, J A Scott

    2014-09-02

    Social neuroscience has called for new experimental paradigms aimed toward real-time interactions. A distinctive feature of interactions is mutual information exchange: One member of a pair changes in response to the other while simultaneously producing actions that alter the other. Combining mathematical and neurophysiological methods, we introduce a paradigm called the human dynamic clamp (HDC), to directly manipulate the interaction or coupling between a human and a surrogate constructed to behave like a human. Inspired by the dynamic clamp used so productively in cellular neuroscience, the HDC allows a person to interact in real time with a virtual partner itself driven by well-established models of coordination dynamics. People coordinate hand movements with the visually observed movements of a virtual hand, the parameters of which depend on input from the subject's own movements. We demonstrate that HDC can be extended to cover a broad repertoire of human behavior, including rhythmic and discrete movements, adaptation to changes of pacing, and behavioral skill learning as specified by a virtual "teacher." We propose HDC as a general paradigm, best implemented when empirically verified theoretical or mathematical models have been developed in a particular scientific field. The HDC paradigm is powerful because it provides an opportunity to explore parameter ranges and perturbations that are not easily accessible in ordinary human interactions. The HDC not only enables to test the veracity of theoretical models, it also illuminates features that are not always apparent in real-time human social interactions and the brain correlates thereof.

  1. Investigating ion channel conformational changes using voltage clamp fluorometry.

    Science.gov (United States)

    Talwar, Sahil; Lynch, Joseph W

    2015-11-01

    Ion channels are membrane proteins whose functions are governed by conformational changes. The widespread distribution of ion channels, coupled with their involvement in most physiological and pathological processes and their importance as therapeutic targets, renders the elucidation of these conformational mechanisms highly compelling from a drug discovery perspective. Thanks to recent advances in structural biology techniques, we now have high-resolution static molecular structures for members of the major ion channel families. However, major questions remain to be resolved about the conformational states that ion channels adopt during activation, drug modulation and desensitization. Patch-clamp electrophysiology has long been used to define ion channel conformational states based on functional criteria. It achieves this by monitoring conformational changes at the channel gate and cannot detect conformational changes occurring in regions distant from the gate. Voltage clamp fluorometry involves labelling cysteines introduced into domains of interest with environmentally sensitive fluorophores and inferring structural rearrangements from voltage or ligand-induced fluorescence changes. Ion channel currents are monitored simultaneously to verify the conformational status. By defining real time conformational changes in domains distant from the gate, this technique provides unexpected new insights into ion channel structure and function. This review aims to summarise the methodology and highlight recent innovative applications of this powerful technique. This article is part of the Special Issue entitled 'Fluorescent Tools in Neuropharmacology'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Time-resolved C-arm cone beam CT angiography (TR-CBCTA) imaging from a single short-scan C-arm cone beam CT acquisition with intra-arterial contrast injection

    Science.gov (United States)

    Li, Yinsheng; Garrett, John W.; Li, Ke; Wu, Yijing; Johnson, Kevin; Schafer, Sebastian; Strother, Charles; Chen, Guang-Hong

    2018-04-01

    Time-resolved C-arm cone-beam CT (CBCT) angiography (TR-CBCTA) images can be generated from a series of CBCT acquisitions that satisfy data sufficiency condition in analytical image reconstruction theory. In this work, a new technique was developed to generate TR-CBCTA images from a single short-scan CBCT data acquisition with contrast media injection. The reconstruction technique enabling this application is a previously developed image reconstruction technique, synchronized multi-artifact reduction with tomographic reconstruction (SMART-RECON). In this new application, the acquired short-scan CBCT projection data were sorted into a union of several sub-sectors of view angles and each sub-sector of view angles corresponds to an individual image volume to be reconstructed. The SMART-RECON method was then used to jointly reconstruct all of these individual image volumes under two constraints: (1) each individual image volume is maximally consistent with the measured cone-beam projection data within the corresponding view angle sector and (2) the nuclear norm of the image matrix is minimized. The difference between these reconstructed individual image volumes is used to generated the desired subtracted angiograms. To validate the technique, numerical simulation data generated from a fractal tree angiogram phantom were used to quantitatively study the accuracy of the proposed method and retrospective in vivo human subject studies were used to demonstrate the feasibility of generating TR-CBCTA in clinical practice.

  3. Neutron beam applications - Development of single crystal structure analysis technique using the HANARO neutron four circle diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Il Hwan; Kim, Moon Jib; Kim, Jin Gyu [Chungnam National University, Taejon (Korea)

    2000-04-01

    As the four circle diffractometer (FCD) has been set up in HANARO, it has become possible to study the single crystal structures by means of the neutron diffraction. Taking account of the geometry of the FCD, a program for the control of te FCD and neutron data acquisition operating under Windows' circumstance has been accomplished. Also, a computer program which can automatically measure the diffraction intensity data has been developed. All data obtained from the FCD are processed automatically for further work and a software for the single crystal structure analyses has been prepared. A KC1 single crystal was selected as first test sample for a structure analysis had been successfully performed on the FCD using in-house developed program and accordingly their functionings with precision were confirmed. For regular single crystal diffraction experiments, the structure analyses of chrysoberyl and Zr(Y)0{sub 1.87} single crystals were performed using both neutron and X-ray diffraction methods, and the result showed that the neutron diffraction work is superior to the X-ray one from the viewpoint of certain crystallographic information obtainable only from the former one. 24 refs., 15 figs., 15 tabs. (Author)

  4. Depth dependence of the single chamber response function of the I'mRT MatriXX array in a 6 MV photon beam

    International Nuclear Information System (INIS)

    Alashrah, Saleh

    2013-01-01

    One of the factors which influence the spatial resolution of a 2D detector array is the size of the single detector, another the transport of the secondary electrons from the walls into the measuring volume. In this study, the single ion chamber dose response function of an I'mRT MatriXX array was determined by comparison between slit beam dose profiles measured with the array and with EBT2 radiochromic film in a solid water-equivalent phantom at a shallow depth of 0.5 cm and at a depth of 5 cm beyond the depth dose maximum for a 6 MV photon beam. The dose response functions were obtained using two methods, the best fit method and the deconvolution method. At the shallow depth, a Lorentz function and at 5 cm depth a Gaussian function, both with the same FWHM of 7.4 mm within limits of uncertainty, were identified as the best suited dose response functions of the 4.5 mm diameter single array chamber. These dose response functions were then tested on various dose profiles whose true shape had been determined with EBT2 film and with the IC03 ionization chamber. By convolving these with the Lorentz kernel (at shallow depth) and the Gaussian kernel (at 5 cm depth) the signal profiles measured with the I'mRT MatriXX array were closely approximated. Thus, the convolution of TPS-calculated dose profiles with these dose response functions can minimize the differences between calculation and measurement which occur due to the limited spatial resolution of the I'mRT MatriXX detector. (orig.)

  5. Load-deflection characteristics of small-bore insulated-pipe clamps

    International Nuclear Information System (INIS)

    Severud, L.K.; Clark, G.L.

    1981-12-01

    The special insulated clamps used on both FFTF and CRBR piping utilize a Belleville spring arrangement to compensate for pipe thermal expansion. Analysis indicates that this produces a non-linear, directionally sensitive clamp spring rate. Since these spring rates influence the seismic response of a supported piping system, it was deemed necessary to evaluate them further by test. This has been accomplished for the FFTF clamps. A more standard insulated pipe clamp, which does not incorporate Belleville springs to accommodate thermal expansion, was also tested. This type clamp is simple in design, and economically attractive. It may have wide application prospects for use in LMFBR small bore auxiliary piping operating at temperatures below 427 0 C. Load deflection tests were conducted on 2.54 CM and 7.62 CM diameter samples of these commercial clamps

  6. GaAs structures with InAs and As quantum dots produced in a single molecular beam epitaxy process

    International Nuclear Information System (INIS)

    Nevedomskii, V. N.; Bert, N. A.; Chaldyshev, V. V.; Preobrazhenskii, V. V.; Putyato, M. A.; Semyagin, B. R.

    2009-01-01

    Epitaxial GaAs layers containing InAs semiconductor quantum dots and As metal quantum dots are grown by molecular beam epitaxy. The InAs quantum dots are formed by the Stranskii-Krastanow mechanism, whereas the As quantum dots are self-assembled in the GaAs layer grown at low temperature with a large As excess. The microstructure of the samples is studied by transmission electron microscopy. It is established that the As metal quantum dots formed in the immediate vicinity of the InAs semiconductor quantum dots are larger in size than the As quantum dots formed far from the InAs quantum dots. This is apparently due to the effect of strain fields of the InAs quantum dots upon the self-assembling of As quantum dots. Another phenomenon apparently associated with local strains around the InAs quantum dots is the formation of V-like defects (stacking faults) during the overgrowth of the InAs quantum dots with the GaAs layer by low-temperature molecular beam epitaxy. Such defects have a profound effect on the self-assembling of As quantum dots. Specifically, on high-temperature annealing needed for the formation of large-sized As quantum dots by Ostwald ripening, the V-like defects bring about the dissolution of the As quantum dots in the vicinity of the defects. In this case, excess arsenic most probably diffuses towards the open surface of the sample via the channels of accelerated diffusion in the planes of stacking faults.

  7. On the excess photon noise in single-beam measurements with photo-emissive and photo-conductive cells

    NARCIS (Netherlands)

    Alkemade, C.T.J.

    In this paper the so-called excess photon noise is theoretically considered with regard to noise power measurements with a single, illumined photo-emissive or photo-conductive cell. Starting from a modification of Mandel's stochastic association of the emission of photo-electrons with wave

  8. COMPARISON OF EARLY AND DELAYED UMBILICAL CORD CLAMPING IN THE THIRD STAGE OF LABOUR

    Directory of Open Access Journals (Sweden)

    Tamara Serdinšek

    2015-09-01

    Full Text Available Background: Umbilical cord clamping in the third stage of labour is still controversial. Early cord clamping is defined as clamping at 10, 15, 30 or 60 seconds after delivery and delayed as clamping after 60 seconds or at 2-5 minutes after delivery, when the cord stops pulsating or when the placenta is visible within the birth canal. Early clamping is one of the three components of active management of the third stage of labour, which has been used widely in modern obstetrics during the last century. However, in some northern European countries, various parts of the USA and Canada and in developing countries physiological management is preferred.Conclusions: After publication of several trials describing advantages of delayed clamping, this has recently been progressively replacing early clamping. The most important advantages of delayed cord clamping are higher haemoglobin and ferritin levels, higher iron stores, lower incidence of iron deficiency anaemia, better cardiopulmonary adaptation, lower rate of respiratory distress syndrome, and longer duration of early breastfeeding in term neonates, while there is no increase in the incidence of postpartum haemorrhage. Delayed clamping seems to bring some advantages for preterm neonates as well. However, caution is still advised because of the potential adverse effects, especially polycythaemia with hyperviscosity, hyperbilirubinaemia and respiratory distress.

  9. Three-dimensional renal CT angiography for guiding segmental renal artery clamping during laparoscopic partial nephrectomy

    International Nuclear Information System (INIS)

    Xu, Yi; Shao, Pengfei; Zhu, Xiaomei; Lv, Qiang; Liu, Wangyan; Xu, Hai; Zhu, Yinsu; Yang, Guangyu; Tang, Lijun; Yin, Changjun

    2013-01-01

    Aim: To evaluate the effectiveness of three-dimensional (3D) renal computed tomography angiography (CTA) in guiding segmental renal artery clamping during laparoscopic partial nephrectomy (LPN). Materials and methods: Forty-three patients with renal tumours undergoing renal CTA before LPN were retrospectively enrolled in this study. 3D arteriogram reconstructed images were created to identify the renal tumour-supplying arteries. The number and location of these targeted vessels were annotated on 3D images preoperatively and compared with the clamped vessels during LPN. The consistency between target vessels annotated at CTA and clamped arteries at LPN was compared both using a patient-based analysis and vessel-based analysis. The χ 2 test was applied to analyse the influence of tumour size, location, and growth pattern on the number of clamped segmental renal branches. Results: On patient-based analysis, the number of targeted vessels was consistent with the clamped vessels during LPN in 33 of 43 patients. On vessel-based analysis, 56 of 65 target vessels annotated at CTA were clamped during LPN. More segmental renal branches (p = 0.04) were clamped in patients with tumours of larger size. Tumour location and growth pattern had no association with the number of clamped segmental branches during LPN. Conclusion: High-quality CTA images and 3D reconstruction images can detect detailed information of tumour-supplying arteries to renal tumours. 3D renal CTA is an effective way to guide segmental renal artery clamping during LPN

  10. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A; Laird, J S; Bardos, R A; Legge, G J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T; Sekiguchi, H [Electrotechnical Laboratory, Tsukuba (Japan).

    1994-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  11. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  12. Pulsewidth-modulated 2-source neutral-point-clamped inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chang; Gao, Feng

    2007-01-01

    This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology for designing a three-level inverter with both voltage-buck and voltage-boost capabilities. The designed Z-source NPC inverter uses two unique X......-shaped inductance-capacitance (LC) impedance networks that are connected between two isolated dc input power sources and its inverter circuitry for boosting its AC output voltage. Through the design of an appropriate pulsewidth-modulation (PWM) algorithm, the two impedance networks can be short......-circuited sequentially (without shooting through the inverter full DC link) for implementing the ldquonearest-three-vectorrdquo modulation principle with minimized harmonic distortion and device commutations per half carrier cycle while performing voltage boosting. With only a slight modification to the inverter PWM...

  13. Thermo-mechanical vibration analysis of a single-walled carbon nanotube embedded in an elastic medium based on higher-order shear deformation beam theory

    International Nuclear Information System (INIS)

    Ebrahimi, Farzad; Salari, Erfan

    2015-01-01

    In this study, the thermal effect on the free vibration characteristics of embedded Single-walled carbon nanotubes (SWCNTs) based on the size-dependent Reddy higher order shear deformation beam theory subjected to in-plane thermal loading is investigated by presenting a Navier-type solution and employing a semi-analytical Differential transform method (DTM) for the first time. In addition, the exact nonlocal Reddy beam theory solution presented here should be useful to engineers designing nanoelectromechanical devices. The small scale effect is considered based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle, and they are solved by applying DTM. Numerical results reveal that the proposed modeling and semi-analytical approach can provide more accurate frequency results of the SWCNTs compared to analytical results and some cases in the literature. The detailed mathematical derivations are presented, and numerical investigations are performed, whereas emphasis is placed on investigating the effect of several parameters such as small-scale effects, boundary conditions, mode number, thickness ratio, temperature change, and Winkler spring modulus on the natural frequencies of the SWCNTs in detail. The vibration behavior of SWCNTs is significantly influenced by these effects. Results indicate that the inclusion of size effect results in a decrease in nanobeam stiffness and leads to a decrease in natural frequency. Numerical results are presented to serve as benchmarks for future analyses of SWCNTs.

  14. Implementation of a cone-beam reconstruction algorithm for the single-circle source orbit with embedded misalignment correction using homogeneous coordinates

    International Nuclear Information System (INIS)

    Karolczak, Marek; Schaller, Stefan; Engelke, Klaus; Lutz, Andreas; Taubenreuther, Ulrike; Wiesent, Karl; Kalender, Willi

    2001-01-01

    We present an efficient implementation of an approximate cone-beam image reconstruction algorithm for application in tomography, which accounts for scanner mechanical misalignment. The implementation is based on the algorithm proposed by Feldkamp et al. [J. Opt. Soc. Am. A 6, 612-619 (1984)] and is directed at circular scan paths. The algorithm has been developed for the purpose of reconstructing volume data from projections acquired in an experimental x-ray microtomography (μCT) scanner [Engelke et al., Der Radiologe 39, 203-212 (1999)]. To mathematically model misalignment we use matrix notation with homogeneous coordinates to describe the scanner geometry, its misalignment, and the acquisition process. For convenience analysis is carried out for x-ray CT scanners, but it is applicable to any tomographic modality, where two-dimensional projection acquisition in cone beam geometry takes place, e.g., single photon emission computerized tomography. We derive an algorithm assuming misalignment errors to be small enough to weight and filter original projections and to embed compensation for misalignment in the backprojection. We verify the algorithm on simulations of virtual phantoms and scans of a physical multidisk (Defrise) phantom

  15. Single-mode molecular beam epitaxy grown PbEuSeTe/PbTe buried-heterostructure diode lasers for CO2 high-resolution spectroscopy

    International Nuclear Information System (INIS)

    Feit, Z.; Kostyk, D.; Woods, R.J.; Mak, P.

    1991-01-01

    Buried-heterostructure tunable PbEuSeTe/PbTe lasers were fabricated using a two-stage molecular beam epitaxy growth procedure. Improvements in the processing technique yielded lasers that show performance characteristics significantly better than those reported previously. A continuous wave (cw) operating temperature of 203 K was realized, which is the highest cw operating temperature ever reported for lead-chalcogenides diode lasers. This laser exhibited exceptionally low-threshold currents of 1.4 mA at 90 K and 43 mA at 160 K with single-mode operation for injection currents up to 30I th and 0.18 mW power at 100 K. The usefulness of the laser, when operating cw at 200 K, was demonstrated by the ability to perform high-resolution spectroscopy of a low-pressure CO 2 gas sample

  16. AN EXACT ELASTO-PLASTIC SOLUTION OF METAL-MATRIX COMPOSITE CANTILEVER BEAM LOADED BY A SINGLE FORCE AT ITS FREE END

    Directory of Open Access Journals (Sweden)

    Onur SAYMAN

    2001-03-01

    Full Text Available In the present study, an elastic-plastic stress analysis is carried out in a metal matrix composite cantilever beam loaded by a single force at its free end. A composite consisting of stainless-steel reinforced aluminium was produced for this work. The orientation angle of the fibers is chosen as 0°, 30°, 45°, 60° and 90°. The material is assumed to be perfectly plastic in the elasto-plastic solution. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. The composite material is assumed as hardening linearly. The Tsai-Hill theory is used as a yield criterion.

  17. Growth mechanisms of plasma-assisted molecular beam epitaxy of green emission InGaN/GaN single quantum wells at high growth temperatures

    International Nuclear Information System (INIS)

    Yang, W. C.; Wu, C. H.; Tseng, Y. T.; Chiu, S. Y.; Cheng, K. Y.

    2015-01-01

    The results of the growth of thin (∼3 nm) InGaN/GaN single quantum wells (SQWs) with emission wavelengths in the green region by plasma-assisted molecular beam epitaxy are present. An improved two-step growth method using a high growth temperature up to 650 °C is developed to increase the In content of the InGaN SQW to 30% while maintaining a strong luminescence intensity near a wavelength of 506 nm. The indium composition in InGaN/GaN SQW grown under group-III-rich condition increases with increasing growth temperature following the growth model of liquid phase epitaxy. Further increase in the growth temperature to 670 °C does not improve the photoluminescence property of the material due to rapid loss of indium from the surface and, under certain growth conditions, the onset of phase separation

  18. Hypoglycaemia and QT interval prolongation in type 1 diabetes - bridging the gap between clamp studies and spontaneous episodes

    DEFF Research Database (Denmark)

    Christensen, Toke F.; Cichosz, Simon Lebech; Tarnow, Lise

    2014-01-01

    AIMS: We propose a study design with controlled hypoglycaemia induced by subcutaneous injection of insulin and matched control episodes to bridge the gap between clamp studies and studies of spontaneous hypoglycaemia. The observed prolongation of the heart rate corrected QT interval (QTc) during...... hypoglycaemia varies greatly between studies. METHODS: We studied ten adults with type 1 diabetes (age 41±15years) without cardiovascular disease or neuropathy. Single-blinded hypoglycaemia was induced by a subcutaneous insulin bolus followed by a control episode on two occasions separated by 4weeks. QT...

  19. Explicit frequency equations of free vibration of a nonlocal Timoshenko beam with surface effects

    Science.gov (United States)

    Zhao, Hai-Sheng; Zhang, Yao; Lie, Seng-Tjhen

    2018-02-01

    Considerations of nonlocal elasticity and surface effects in micro- and nanoscale beams are both important for the accurate prediction of natural frequency. In this study, the governing equation of a nonlocal Timoshenko beam with surface effects is established by taking into account three types of boundary conditions: hinged-hinged, clamped-clamped and clamped-hinged ends. For a hinged-hinged beam, an exact and explicit natural frequency equation is obtained. However, for clamped-clamped and clamped-hinged beams, the solutions of corresponding frequency equations must be determined numerically due to their transcendental nature. Hence, the Fredholm integral equation approach coupled with a curve fitting method is employed to derive the approximate fundamental frequency equations, which can predict the frequency values with high accuracy. In short, explicit frequency equations of the Timoshenko beam for three types of boundary conditions are proposed to exhibit directly the dependence of the natural frequency on the nonlocal elasticity, surface elasticity, residual surface stress, shear deformation and rotatory inertia, avoiding the complicated numerical computation.

  20. A patch-clamp ASIC for nanopore-based DNA analysis.

    Science.gov (United States)

    Kim, Jungsuk; Maitra, Raj; Pedrotti, Kenneth D; Dunbar, William B

    2013-06-01

    In this paper, a fully integrated high-sensitivity patch-clamp system is proposed for single-molecule deoxyribonucleic acid (DNA) analysis using a nanopore sensor. This system is composed of two main blocks for amplification and compensation. The amplification block is composed of three stages: 1) a headstage, 2) a voltage-gain difference amplifier, and 3) a track-and-hold circuit, that amplify a minute ionic current variation sensed by the nanopore while the compensation block avoids the headstage saturation caused by the input parasitic capacitances during sensing. By employing design techniques novel for this application, such as an instrumentation--amplifier topology and a compensation switch, we minimize the deleterious effects of the input-offset voltage and the input parasitic capacitances while attaining hardware simplicity. This system is fabricated in a 0.35 μm 4M2P CMOS process and is demonstrated using an α-hemolysin protein nanopore for detection of individual molecules of single-stranded DNA that pass through the 1.5 nm-diameter pore. In future work, the refined system will functionalize single and multiple solid-state nanopores formed in integrated microfluidic devices for advanced DNA analysis, in scientific and diagnostic applications.

  1. Clamped end conditions and cross section deformation in the finite element absolute nodal coordinate formulation

    International Nuclear Information System (INIS)

    Hussein, Bassam A.; Weed, David; Shabana, Ahmed A.

    2009-01-01

    In the finite element absolute nodal coordinate formulation (ANCF), the elimination of the relative translations and rotations at a point does not necessarily define a fully clamped joint, particularly in the case of fully parameterized ANCF finite elements that allow for the deformation of the cross section. In this investigation, the formulations and results of two different sets of clamped end conditions that define two different joints are compared. The first joint, called the partially clamped joint, eliminates only the translations and rotations at a point on the cross section. The second joint, called the fully clamped joint, eliminates all the translation, rotation and deformation degrees of freedom at a point on the cross section. The kinematic equations that define the partially and fully clamped joints are developed, and the dynamic equations used in the comparative numerical study presented in this paper are shown. As discussed in this investigation, the fully clamped joint does not allow for the deformation of the cross section at the joint node since the gradient vectors remain orthogonal unit vectors. The partially clamped joint, on the other hand, allows for the deformation of the cross section. Nanson's formula is used as a measure of the deformation of the cross section in the case of the partially clamped joint. A very flexible pendulum that has a rigid body attached to its free end is used to compare the results of the partially and fully clamped joints. The numerical results obtained using this very flexible pendulum example show that, while the type of joint (partially or fully clamped) does not significantly affect the gross reference motion of the system, there are fundamental differences between the two joints since the partially clamped joint allows for the cross section deformations at the joint node

  2. Diode-pumped, single frequency Nd:YLF laser for 60-beam OMEGA laser pulse-shaping system

    International Nuclear Information System (INIS)

    Okishev, A.V.; Seka, W.

    1997-01-01

    The operational conditions of the OMEGA pulse-shaping system require an extremely reliable and low-maintenance master oscillator. The authors have developed a diode-pumped, single-frequency, pulsed Nd:YLF laser for this application. The laser generates Q-switched pulses of ∼160-ns duration and ∼10-microJ energy content at the 1,053-nm wavelength with low amplitude fluctuations (<0.6% rms) and low temporal jitter (<7 ns rms). Amplitude and frequency feedback stabilization systems have been used for high long-term amplitude and frequency stability

  3. The clinical results of proton beam therapy in patients with idiopathic pulmonary fibrosis: a single center experience

    International Nuclear Information System (INIS)

    Ono, Takashi; Hareyama, Masato; Nakamura, Tatsuya; Kimura, Kanako; Hayashi, Yuichiro; Azami, Yusuke; Hirose, Katsumi; Hatayama, Yoshiomi; Suzuki, Motohisa; Wada, Hitoshi; Kikuchi, Yasuhiro; Nemoto, Kenji

    2016-01-01

    The purpose of this study is to retrospectively evaluate the incidence of lung toxicities after proton beam therapy (PBT) in patients with idiopathic pulmonary fibrosis (IPF). Patients diagnosed with primary lung cancer or lung metastasis who were treated with PBT between January 2009 and May 2015 were recruited from our database retrospectively. Cases of pneumonitis (excluding infection-related pneumonitis) were evaluated using the Common Terminology Criteria for Adverse Events version 4.0, and the Fletcher-Hugh-Jones classification of respiratory status was used to evaluate pretreatment and posttreatment respiratory function. Sixteen IPF patients received PBT for lung tumors, 15 received PBT for primary lung cancer, and one patient received PBT for metastasis from lung cancer. The cohort was composed of 14 men and 2 women, with a median age of 76 years (range: 63–89 years). The median follow-up time was 12 months (range: 4–39 months). The median dose of PBT was 80.0 Gy relative biological dose effectiveness (RBE) (range: 66.0–86.4 Gy [RBE]). The cumulative incidence of pneumonitis was 19.8 % (95 % confidence interval [CI]: 0–40.0 %), including one case of grade 5 pneumonitis. Reduced respiratory function was observed after PBT in seven patients, including one patient with pleural dissemination; five of these patients required home oxygen therapy. This study suggests that PBT can be performed more safely in IPF patients than surgery or X-ray irradiation. Although PBT has become a treatment choice for lung tumors of patients with IPF, the adverse events warrant serious attention

  4. Electro-optic deflectors deliver advantages over acousto-optical deflectors in a high resolution, ultra-fast force-clamp optical trap.

    Science.gov (United States)

    Woody, Michael S; Capitanio, Marco; Ostap, E Michael; Goldman, Yale E

    2018-04-30

    We characterized experimental artifacts arising from the non-linear response of acousto-optical deflectors (AODs) in an ultra-fast force-clamp optical trap and have shown that using electro-optical deflectors (EODs) instead eliminates these artifacts. We give an example of the effects of these artifacts in our ultra-fast force clamp studies of the interaction of myosin with actin filaments. The experimental setup, based on the concept of Capitanio et al. [Nat. Methods 9, 1013-1019 (2012)] utilizes a bead-actin-bead dumbbell held in two force-clamped optical traps which apply a load to the dumbbell to move it at a constant velocity. When myosin binds to actin, the filament motion stops quickly as the total force from the optical traps is transferred to the actomyosin attachment. We found that in our setup, AODs were unsuitable for beam steering due to non-linear variations in beam intensity and deflection angle as a function of driving frequency, likely caused by low-amplitude standing acoustic waves in the deflectors. These aberrations caused instability in the force feedback loops leading to artifactual jumps in the trap position. We demonstrate that beam steering with EODs improves the performance of our instrument. Combining the superior beam-steering capability of the EODs, force acquisition via back-focal-plane interferometry, and dual high-speed FPGA-based feedback loops, we apply precise and constant loads to study the dynamics of interactions between actin and myosin. The same concept applies to studies of other biomolecular interactions.

  5. Crystal structure of DNA polymerase III β sliding clamp from Mycobacterium tuberculosis.

    Science.gov (United States)

    Gui, Wen-Jun; Lin, Shi-Qiang; Chen, Yuan-Yuan; Zhang, Xian-En; Bi, Li-Jun; Jiang, Tao

    2011-02-11

    The sliding clamp is a key component of DNA polymerase III (Pol III) required for genome replication. It is known to function with diverse DNA repair proteins and cell cycle-control proteins, making it a potential drug target. To extend our understanding of the structure/function relationship of the sliding clamp, we solved the crystal structure of the sliding clamp from Mycobacterium tuberculosis (M. tuberculosis), a human pathogen that causes most cases of tuberculosis (TB). The sliding clamp from M. tuberculosis forms a ring-shaped head-to-tail dimer with three domains per subunit. Each domain contains two α helices in the inner ring that lie against two β sheets in the outer ring. Previous studies have indicated that many Escherichia coli clamp-binding proteins have a conserved LF sequence, which is critical for binding to the hydrophobic region of the sliding clamp. Here, we analyzed the binding affinities of the M. tuberculosis sliding clamp and peptides derived from the α and δ subunits of Pol III, which indicated that the LF motif also plays an important role in the binding of the α and δ subunits to the sliding clamp of M. tuberculosis. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Scale-dependent effects on wave propagation in magnetically affected single/double-layered compositionally graded nanosize beams

    Science.gov (United States)

    Ebrahimi, Farzad; Barati, Mohammad Reza

    2018-04-01

    This article deals with the wave propagation analysis of single/double layered functionally graded (FG) size-dependent nanobeams in elastic medium and subjected to a longitudinal magnetic field employing nonlocal elasticity theory. Material properties of nanobeam change gradually according to the sigmoid function. Applying an analytical solution, the acoustical and optical dispersion relations are explored for various wave number, nonlocality parameter, material composition, elastic foundation constants, and magnetic field intensity. It is found that frequency and phase velocity of waves propagating in S-FGM nanobeam are significantly affected by these parameters. Also, presence of cut-off and escape frequencies in wave propagation analysis of embedded S-FGM nanobeams is investigated.

  7. In-vitro Assessing the Shaping Ability of Three Nickel-Titanium Rotary Single File Systems by Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Ali Imad Al-Asadi

    2018-02-01

    Full Text Available Aim of the study was to evaluate the canal transportation and centering ability of three nickel-titanium single file rotary systems by cone beam computed tomography (CBCT. Materials and methods: Thirty permanent maxillary first molar with a range of mesiobuccal canals curvature from 20-30 degree were selected and assigned into three groups (n=10, according to the biomechanical preparation system used: Hyflex EDM (HF, Reciproc blue (RB and OneShape (OS. The sampled were scanned by CBCT after being mounted on customized acrylic base and then rescanned after the instrumentation. Slices from the axial section were taken from both exposures at 3 mm, 6 mm and 9 mm from the root apex corresponding to the apical, middle, and coronal third respectively. Data were statistically analyzed using Kurskal-Wallis and Mann-Whitney U tests at the 5% confidence level. Results: The results showed that there were no significant differences at the apical and coronal third and a significant difference at the middle third regarding canal transportation. However, there was a significant difference at the apical third and no significant difference at the middle and coronal third regarding centering ratio. Conclusion: It was concluded that the three single rotary systems reported a degree in canal transportation and centric ratio but the Hyflex EDM reported the least one.

  8. Increased apoptotic potential and dose-enhancing effect of gold nanoparticles in combination with single-dose clinical electron beams on tumor-bearing mice

    International Nuclear Information System (INIS)

    Chang Mengya; Chen Yuhung; Chang Chihjui; Chen Helen H-W; Wu Chaoliang; Shiau Aili

    2008-01-01

    High atomic number material, such as gold, may be used in conjunction with radiation to provide dose enhancement in tumors. In the current study, we investigated the dose-enhancing effect and apoptotic potential of gold nanoparticles in combination with single-dose clinical electron beams on B16F10 melanoma tumor-bearing mice. We revealed that the accumulation of gold nanoparticles was detected inside B16F10 culture cells after 18 h of incubation, and moreover, the gold nanoparticles were shown to be colocalized with endoplasmic reticulum and Golgi apparatus in cells. Furthermore, gold nanoparticles radiosensitized melanoma cells in the colony formation assay (P=0.02). Using a B16F10 tumor-bearing mouse model, we further demonstrated that gold nanoparticles in conjunction with ionizing radiation significantly retarded tumor growth and prolonged survival compared to the radiation alone controls (P<0.05). Importantly, an increase of apoptotic signals was detected inside tumors in the combined treatment group (P<0.05). Knowing that radiation-induced apoptosis has been considered a determinant of tumor responses to radiation therapy, and the length of tumor regrowth delay correlated with the extent of apoptosis after single-dose radiotherapy, these results may suggest the clinical potential of gold nanoparticles in improving the outcome of melanoma radiotherapy. (author)

  9. Modeling of SVM Diode Clamping Three-Level Inverter Connected to Grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    PLECS is used to model the diode clamping three-level inverter connected to grid and good results are obtained. First the output voltage SVM is described for diode clamping three-level inverter with loads connected to Y. Then the output voltage SVM of diode clamping three-level inverter is simply...... analyzed with loads connected to △. But it will be further researched in the future. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping three-level inverter is briefly presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS...... is very powerful tool to real power circuits and it is very easy to simulate them. They have also verified that SVM control strategy is feasible to control the diode clamping three-level inverter....

  10. Modulation of the Pyrococcus abyssi NucS endonuclease activity by replication clamp at functional and structural levels.

    Science.gov (United States)

    Creze, Christophe; Ligabue, Alessio; Laurent, Sébastien; Lestini, Roxane; Laptenok, Sergey P; Khun, Joelle; Vos, Marten H; Czjzek, Mirjam; Myllykallio, Hannu; Flament, Didier

    2012-05-04

    Pyrococcus abyssi NucS is the founding member of a new family of structure-specific DNA endonucleases that interact with the replication clamp proliferating cell nuclear antigen (PCNA). Using a combination of small angle x-ray scattering and surface plasmon resonance analyses, we demonstrate the formation of a stable complex in solution, in which one molecule of the PabNucS homodimer binds to the outside surface of the PabPCNA homotrimer. Using fluorescent labels, PCNA is shown to increase the binding affinity of NucS toward single-strand/double-strand junctions on 5' and 3' flaps, as well as to modulate the cleavage specificity on the branched DNA structures. Our results indicate that the presence of a single major contact between the PabNucS and PabPCNA proteins, together with the complex-induced DNA bending, facilitate conformational flexibility required for specific cleavage at the single-strand/double-strand DNA junction.

  11. Ion-beam-driven amorphization of Ca2La8(SiO4)6O2 single crystals

    International Nuclear Information System (INIS)

    Weber, W.J.; Hess, N.J.; Wang, L.M.

    1993-11-01

    Single crystals of Ca 2 La 8 (SiO 4 ) 6 O 2 , with 1% Nd substituted for La, were irradiated with 0.8 MeV Ne + and 1.5 MeV Kr + ions from 15 to 773 K. The irradiations were carried out using the HVEM-Tandem Facility at Argonne National Laboratory. The structural changes and the ion fluence for complete amorphization were determined by in situ transmission electron microscopy. The ion fluence for complete amorphization increased with temperature in two stages associated with defect annealing processes. The critical temperature for amorphization increased from ∼360 K for 0.8 MeV Ne + to ∼710 K for 1.5 MeV Kr + . During in situ annealing studies, irradiation-enhanced recrystallization was observed at 923 K. Spatially-resolved fluorescence spectra of the Nd ion excited with 488.0 mn laser excitation showed marked line-broadening toward the center of the amorphous regions. Initial measurements indicate the subtle shifts of the 9 I 9/2 groundstate energy levels can be measured by pumping directly into the excited state 4 F 3/2 manifold suggesting that the line broadening observed originates from a distribution of geometrically distorted Nd sites

  12. Scanned ion beam therapy for prostate carcinoma. Comparison of single plan treatment and daily plan-adapted treatment

    International Nuclear Information System (INIS)

    Hild, Sebastian; Graeff, Christian; Rucinski, Antoni; Zink, Klemens; Habl, Gregor; Durante, Marco; Herfarth, Klaus; Bert, Christoph

    2016-01-01

    Intensity-modulated particle therapy (IMPT) for tumors showing interfraction motion is a topic of current research. The purpose of this work is to compare three treatment strategies for IMPT to determine potential advantages and disadvantages of ion prostate cancer therapy. Simulations for three treatment strategies, conventional one-plan radiotherapy (ConvRT), image-guided radiotherapy (IGRT), and online adaptive radiotherapy (ART) were performed employing a dataset of 10 prostate cancer patients with six CT scans taken at one week intervals. The simulation results, using a geometric margin concept (7-2 mm) as well as patient-specific internal target volume definitions for IMPT were analyzed by target coverage and exposure of critical structures on single fraction dose distributions. All strategies led to clinically acceptable target coverage in patients exhibiting small prostate motion (mean displacement < 4 mm), but IGRT and especially ART led to significant sparing of the rectum. In 20 % of the patients, prostate motion exceeded 4 mm causing insufficient target coverage for ConvRT (V95 mean = 0.86, range 0.63-0.99) and IGRT (V95 mean = 0.91, range 0.68-1.00), while ART maintained acceptable target coverage. IMPT of prostate cancer demands consideration of rectal sparing and adaptive treatment replanning for patients exhibiting large prostate motion. (orig.) [de

  13. Optimization of Natural Frequencies and Sound Power of Beams Using Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Nabeel T. Alshabatat

    2014-01-01

    Full Text Available This paper presents a design method to optimize the material distribution of functionally graded beams with respect to some vibration and acoustic properties. The change of the material distribution through the beam length alters the stiffness and the mass of the beam. This can be used to alter a specific beam natural frequency. It can also be used to reduce the sound power radiated from the vibrating beam. Two novel volume fraction laws are used to describe the material volume distributions through the length of the FGM beam. The proposed method couples the finite element method (for the modal and harmonic analysis, Lumped Parameter Model (for calculating the power of sound radiation, and an optimization technique based on Genetic Algorithm. As a demonstration of this technique, the optimization procedure is applied to maximize the fundamental frequency of FGM cantilever and clamped beams and to minimize the sound radiation from vibrating clamped FGM beam at a specific frequency.

  14. Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study

    Science.gov (United States)

    Agarwal, Jatin; Jain, Pradeep; Chandra, Anil

    2015-01-01

    Background The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems. Aim The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT). Materials and Methods Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20o to 35o were divided into three groups of 20 samples each: ProTaper PT (group I) – full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO – single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey’s honestly significant difference test. Results It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant Conclusion It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal

  15. Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study.

    Science.gov (United States)

    Agarwal, Rolly S; Agarwal, Jatin; Jain, Pradeep; Chandra, Anil

    2015-05-01

    The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems. The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT). Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20(o) to 35(o) were divided into three groups of 20 samples each: ProTaper PT (group I) - full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO - single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference test. It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant. It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal transportation and centering ability comparable to full sequence

  16. Statics and rotational dynamics of composite beams

    CERN Document Server

    Ghorashi, Mehrdaad

    2016-01-01

    This book presents a comprehensive study of the nonlinear statics and dynamics of composite beams and consists of solutions with and without active elements embedded in the beams. The static solution provides the initial conditions for the dynamic analysis. The dynamic problems considered include the analyses of clamped (hingeless) and articulated (hinged) accelerating rotating beams. Two independent numerical solutions for the steady state and the transient responses are presented. The author illustrates that the transient solution of the nonlinear formulation of accelerating rotating beam converges to the steady state solution obtained by the shooting method. Other key areas considered include calculation of the effect of perturbing the steady state solution, coupled nonlinear flap-lag dynamics of a rotating articulated beam with hinge offset and aerodynamic damping, and static and dynamic responses of nonlinear composite beams with embedded anisotropic piezo-composite actuators. The book is intended as a t...

  17. Broad Beam and Ion Microprobe Studies of Single-Event Upsets in High Speed 0.18micron Silicon Germanium Heterojunction Bipolar Transistors and Circuits

    Science.gov (United States)

    Reed, Robert A.; Marshall, Paul W.; Pickel, Jim; Carts, Martin A.; Irwin, TIm; Niu, Guofu; Cressler, John; Krithivasan, Ramkumar; Fritz, Karl; Riggs, Pam

    2003-01-01

    SiGe based technology is widely recognized for its tremendous potential to impact the high speed microelectronic industry, and therefore the space industry, by monolithic incorporation of low power complementary logic with extremely high speed SiGe Heterojunction Bipolar Transistor (HBT) logic. A variety of studies have examined the ionizing dose, displacement damage and single event characteristics, and are reported. Accessibility to SiGe through an increasing number of manufacturers adds to the importance of understanding its intrinsic radiation characteristics, and in particular the single event effect (SEE) characteristics of the high bandwidth HBT based circuits. IBM is now manufacturing in its 3rd generation of their commercial SiGe processes, and access is currently available to the first two generations (known as and 6HP) through the MOSIS shared mask services with anticipated future release of the latest (7HP) process. The 5 HP process is described and is characterized by a emitter spacing of 0.5 micron and a cutoff frequency ff of 50 GHz, whereas the fully scaled 7HP HBT employs a 0.18 micron emitter and has an fT of 120 GHz. Previous investigations have the examined SEE response of 5 HP HBT circuits through both circuit testing and modeling. Charge collection modeling studies in the 5 H P process have also been conducted, but to date no measurements have been reported of charge collection in any SiGe HBT structures. Nor have circuit models for charge collection been developed in any version other than the 5 HP HBT structure. Our investigation reports the first indications of both charge collection and circuit response in IBM s 7HP-based SiGe process. We compare broad beam heavy ion SEU test results in a fully function Pseudo-Random Number (PRN) sequence generator up to frequencies of 12 Gbps versus effective LET, and also report proton test results in the same circuit. In addition, we examine the charge collection characteristics of individual 7HP HBT

  18. Scanned ion beam therapy for prostate carcinoma. Comparison of single plan treatment and daily plan-adapted treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hild, Sebastian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nuernberg (FAU), Department of Radiation Oncology, Erlangen (Germany); Graeff, Christian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); Rucinski, Antoni [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Sapienza Universit' a di Roma, Dipartimento di Scienze di Base e Applicate per Ingegneria, Roma (Italy); INFN, Roma (Italy); Zink, Klemens [University of Applied Sciences, Institute for Medical Physics and Radiation Protection, Giessen (Germany); University Medical Center Giessen-Marburg, Department of Radiotherapy and Radiooncology, Marburg (Germany); Habl, Gregor [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Klinikum rechts der Isar, Technische Universitaet Muenchen (TUM), Department of Radiation Oncology, Munich (Germany); Durante, Marco [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); Technische Universitaet Darmstadt, Faculty of Physics, Darmstadt (Germany); Herfarth, Klaus [University Clinic Heidelberg, Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, Heidelberg (Germany); Bert, Christoph [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Department of Biophysics, Darmstadt (Germany); University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nuernberg (FAU), Department of Radiation Oncology, Erlangen (Germany); University Hospital Erlangen, Radiation Oncology, Erlangen (Germany)

    2016-02-15

    Intensity-modulated particle therapy (IMPT) for tumors showing interfraction motion is a topic of current research. The purpose of this work is to compare three treatment strategies for IMPT to determine potential advantages and disadvantages of ion prostate cancer therapy. Simulations for three treatment strategies, conventional one-plan radiotherapy (ConvRT), image-guided radiotherapy (IGRT), and online adaptive radiotherapy (ART) were performed employing a dataset of 10 prostate cancer patients with six CT scans taken at one week intervals. The simulation results, using a geometric margin concept (7-2 mm) as well as patient-specific internal target volume definitions for IMPT were analyzed by target coverage and exposure of critical structures on single fraction dose distributions. All strategies led to clinically acceptable target coverage in patients exhibiting small prostate motion (mean displacement < 4 mm), but IGRT and especially ART led to significant sparing of the rectum. In 20 % of the patients, prostate motion exceeded 4 mm causing insufficient target coverage for ConvRT (V95{sub mean} = 0.86, range 0.63-0.99) and IGRT (V95{sub mean} = 0.91, range 0.68-1.00), while ART maintained acceptable target coverage. IMPT of prostate cancer demands consideration of rectal sparing and adaptive treatment replanning for patients exhibiting large prostate motion. (orig.) [German] Adaptive Therapieansaetze fuer sich interfraktionell bewegende Zielvolumina in der intensitaetsmodulierten Partikeltherapie (IMPT) befinden sich zurzeit in der Entwicklung. In dieser Arbeit werden drei Behandlungsstrategien auf moegliche Vor- und Nachteile in der IMPT des Prostatakarzinoms hin untersucht. Auf Basis eines anonymisierten Datensatzes aus 10 Patienten mit Prostatakarzinom wurden die drei Bestrahlungsstrategien, konventionelle Ein-Plan-Strahlentherapie (ConvRT), bildunterstuetzte Strahlentherapie (IGRT) und tagesaktuelle Strahlentherapie (adaptive radiotherapy,ART), simuliert

  19. Dynamic assembly of Hda and the sliding clamp in the regulation of replication licensing.

    Science.gov (United States)

    Kim, Jin S; Nanfara, Michael T; Chodavarapu, Sundari; Jin, Kyeong S; Babu, Vignesh M P; Ghazy, Mohamed A; Chung, Scisung; Kaguni, Jon M; Sutton, Mark D; Cho, Yunje

    2017-04-20

    Regulatory inactivation of DnaA (RIDA) is one of the major regulatory mechanisms of prokaryotic replication licensing. In RIDA, the Hda-sliding clamp complex loaded onto DNA directly interacts with adenosine triphosphate (ATP)-bound DnaA and stimulates the hydrolysis of ATP to inactivate DnaA. A prediction is that the activity of Hda is tightly controlled to ensure that replication initiation occurs only once per cell cycle. Here, we determined the crystal structure of the Hda-β clamp complex. This complex contains two pairs of Hda dimers sandwiched between two β clamp rings to form an octamer that is stabilized by three discrete interfaces. Two separate surfaces of Hda make contact with the β clamp, which is essential for Hda function in RIDA. The third interface between Hda monomers occludes the active site arginine finger, blocking its access to DnaA. Taken together, our structural and mutational analyses of the Hda-β clamp complex indicate that the interaction of the β clamp with Hda controls the ability of Hda to interact with DnaA. In the octameric Hda-β clamp complex, the inability of Hda to interact with DnaA is a novel mechanism that may regulate Hda function. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. Analysis and Experiments on Sea Load and Fastened Mechanics on Pipe Clamps

    Directory of Open Access Journals (Sweden)

    Wang Zhuo

    2017-08-01

    Full Text Available When an offshore oil field completed and put into production, new subsea pipelines and the new cable need to be established. Cable protection pipe clamp is used to fix cable protection pipe on the jacket. In order to avoid the problem of traditional steel structure clamp splice, counterpoint, fastening difficulty when installed cable protection pipe under water, reduce the risk and workload of under water, This paper develop a new type of portable connecting riser clamp -“backpack clamp” which solve the riser cable protection pipe difficult underwater installation problem. The main structure of backpack clamp used three valves type structure. The load characteristic of a clamping device was determined by the Morison equation which was a classical theory. Clamp device underwater mechanics analysis model was established. The minimum tension pre-tightening force was determined. The results show that the strength of the base meets the requirements after strength analysis with finite element analysis method, stability and strength experiments, which means the clamp based on resin matrix composite is feasible.

  1. Analysis of the role of PCNA-DNA contacts during clamp loading

    Directory of Open Access Journals (Sweden)

    Goedken Eric R

    2010-01-01

    Full Text Available Abstract Background Sliding clamps, such as Proliferating Cell Nuclear Antigen (PCNA in eukaryotes, are ring-shaped protein complexes that encircle DNA and enable highly processive DNA replication by serving as docking sites for DNA polymerases. In an ATP-dependent reaction, clamp loader complexes, such as the Replication Factor-C (RFC complex in eukaryotes, open the clamp and load it around primer-template DNA. Results We built a model of RFC bound to PCNA and DNA based on existing crystal structures of clamp loaders. This model suggests that DNA would enter the clamp at an angle during clamp loading, thereby interacting with positively charged residues in the center of PCNA. We show that simultaneous mutation of Lys 20, Lys 77, Arg 80, and Arg 149, which interact with DNA in the RFC-PCNA-DNA model, compromises the ability of yeast PCNA to stimulate the DNA-dependent ATPase activity of RFC when the DNA is long enough to extend through the clamp. Fluorescence anisotropy binding experiments show that the inability of the mutant clamp proteins to stimulate RFC ATPase activity is likely caused by reduction in the affinity of the RFC-PCNA complex for DNA. We obtained several crystal forms of yeast PCNA-DNA complexes, measuring X-ray diffraction data to 3.0 Å resolution for one such complex. The resulting electron density maps show that DNA is bound in a tilted orientation relative to PCNA, but makes different contacts than those implicated in clamp loading. Because of apparent partial disorder in the DNA, we restricted refinement of the DNA to a rigid body model. This result contrasts with previous analysis of a bacterial clamp bound to DNA, where the DNA was well resolved. Conclusion Mutational analysis of PCNA suggests that positively charged residues in the center of the clamp create a binding surface that makes contact with DNA. Disruption of this positive surface, which had not previously been implicated in clamp loading function, reduces RFC

  2. Investigation on the Behavior of the Jointing Clamps to the Simulated Environmental - LOCA

    International Nuclear Information System (INIS)

    Ivan, P.; Segarceanu, D.; Geambasu, C.

    2002-01-01

    The paper presents the main aspect concerning the electric parameter variation of jointing clamps operating under specific environmental conditions determinate by pressure, temperature and humidity. The testing of jointing clamps capability to meet and exceed the required performances all along its operating life implies the performing of LOCA simulation conditions while the jointing clamps is bright in a relatively short time under conditions equivalent to those at the end of its service life. The paper describes ageing and measurement techniques and the analyses of electric parameter behaviour in these environmental simulated conditions. (author)

  3. High-Dose-Rate Brachytherapy of a Single Implant With Two Fractions Combined With External Beam Radiotherapy for Hormone-Naive Prostate Cancer

    International Nuclear Information System (INIS)

    Sato, Morio; Mori, Takashi; Shirai, Shintaro; Kishi, Kazushi; Inagaki, Takeshi; Hara, Isao

    2008-01-01

    Purpose: To evaluate the preliminary outcomes of high-dose-rate (HDR) brachytherapy of a single implant with two fractions and external beam radiotherapy (EBRT) for hormone-naive prostate cancer. Methods and Materials: Between March 2000 and Sept 2003, a total of 53 patients with tumor Stage T1c-T3b N0 M0 prostate cancer were treated with HDR brachytherapy boost doses (7.5 Gy/fraction) and 50-Gy EBRT during a 5.5-week period. Median follow-up was 61 months. Patients were divided into groups with localized (T1c-T2b) and advanced disease (T3a-T3b). We used the American Society for Therapeutic Radiology and Oncology (ASTRO) definition for biochemical failure. According to recommendations of the Radiation Therapy Oncology Group-ASTRO Phoenix Consensus Conference, biochemical failure-free control rates (BF-FCRs) at 3 years were investigated as 2 years short of the median follow-up. Results: Between April 2000 and Sept 2007, Common Terminology Criteria for Adverse Events Version 2.0 late Grade 2 genitourinary and gastrointestinal toxicity rates were 0% and 3.8%, respectively. Erectile preservation was 25% at 5 years. Overall survival was 88.1% and cause-specific survival was 100%. At 3 years, ASTRO BF-FCRs of the localized and advanced groups were 100% and 42%, respectively (p = 0.001). Conclusions: The HDR brachytherapy of a single implant with two fractions plus EBRT is effective in treating patients with localized hormone-naive prostate cancer, with the least genitourinary and gastrointestinal toxicities; however, longer median BF-FCR follow-up is required to assess these findings

  4. Evaluation of Single File Systems Reciproc, Oneshape, and WaveOne using Cone Beam Computed Tomography –An In Vitro Study

    Science.gov (United States)

    Dhingra, Annil; Miglani, Anjali

    2015-01-01

    Background Successful endodontic therapy depends on many factor, one of the most important step in any root canal treatment is root canal preparation. In addition, respecting the original shape of the canal is of the same importance; otherwise, canal aberrations such as transportation will be created. Aim The purpose of this study is to compare and evaluate Reciprocating WaveOne ,Reciproc and Rotary Oneshape Single File Instrumentation System On Cervical Dentin Thickness, Cross Sectional Area and Canal Transportation on First Mandibular Molar Using Cone Beam Computed Tomography. Materials and Methods Sixty Mandibular First Molars extracted due to periodontal reason was collected from the Department of Oral and Maxillofacial. Teeth were prepared using one rotary and two reciprocating single file system. Teeth were divided into 3 groups 20 teeth in each group. Pre instrumentation and Post instrumentation scans was done and evaluated for three parameters Canal Transportation, Cervical Dentinal Thickness, Cross-sectional Area. Results were analysed statistically using ANOVA, Post-Hoc Tukey analysis. Results The change in cross-sectional area after filing showed significant difference at 0mm, 1mm, 2mm and 7mm (pfile system over a distance of 7 mm (starting from 0mm and then evaluation at 1mm, 2mm, 3mm, 5mm and 7mm), the results showed a significant difference among the file systems at various lengths (p= 0.014, 0.046, 0.004, 0.028, 0.005 & 0.029 respectively). Mean value of cervical dentinal removal is maximum at all the levels for oneshape and minimum for waveone showing the better quality of waveone and reciproc over oneshape file system. Significant difference was found at 9mm, 11mm and 12mm between all the three file systems (p<0.001,< 0.001, <0.001). Conclusion It was concluded that reciprocating motion is better than rotary motion in all the three parameters Canal Transportation, Cross-sectional Area, Cervical Dentinal Thickness. PMID:26023639

  5. Single-fraction flattening filter–free volumetric modulated arc therapy for lung cancer: Dosimetric results and comparison with flattened beams technique

    Energy Technology Data Exchange (ETDEWEB)

    Barbiero, Sara [Medical Physics Division, Centro di Riferimento Oncologico, Aviano (Italy); Specialty School in Medical Physics, University of Pisa, Pisa (Italy); Rink, Alexandra [Radiation Physics Department, Princess Margaret Cancer Centre, University Health Network, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Matteucci, Fabrizio [Radiation Oncology Department, S.Chiara University Hospital, Pisa (Italy); Fedele, David [Radiotherapy Department, Casa di Cura S. Rossore, Pisa (Italy); Paiar, Fabiola; Pasqualetti, Francesco [Radiation Oncology Department, S.Chiara University Hospital, Pisa (Italy); Avanzo, Michele, E-mail: mavanzo@cro.it [Medical Physics Division, Centro di Riferimento Oncologico, Aviano (Italy)

    2016-01-01

    Purpose: To report on single-fraction stereotactic body radiotherapy (RT) (SBRT) with flattening filter (FF)–free (FFF) volumetric modulated arc therapy (VMAT) for lung cancer and to compare dosimetric results with VMAT with FF. Methods and materials: Overall, 25 patients were treated with 6-MV FFF VMAT (Varian TrueBeam STx LINAC) to a prescribed dose of 24 Gy in a single fraction. Treatment plans were recreated using FF VMAT. Dose-volume indices, monitor units (MU), and treatment times were compared between FFF and FF VMAT techniques. Results: Dose constraints to PTV, spinal cord, and lungs were reached in FFF and FF plans. In FFF plans, average conformity index was 1.13 (95% CI: 1.07 to1.38). Maximum doses to spinal cord, heart, esophagus, and trachea were 2.9 Gy (95% CI: 0.4 to 6.7 Gy), 0.8 Gy (95% CI: 0 to 3.6 Gy), 3.3 Gy (95% CI: 0.02 to 13.9 Gy), and 1.5 Gy (95% CI: 0 to 4.9 Gy), respectively. Average V7 Gy, V7.4 Gy, and mean dose to the healthy lung were 126.5 cc (95% CI: 41.3 to 248.9 cc), 107.3 cc (95% CI: 18.7 to 232.8 cc), and 1.1 Gy (95% CI: 0.3 to 2.2 Gy), respectively. No statistically significant differences were found in dosimetric results and MU between FF and FFF treatments. Treatment time was reduced by an average factor of 2.31 (95% CI: 2.15 to 2.43) from FF treatments to FFF, and the difference was statistically significant. Conclusions: FFF VMAT for lung SBRT provides equivalent dosimetric results to the target and organs at risk as FF VMAT while significantly reducing treatment time.

  6. Use of the Universal Clamp in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Sales de Gauzy, Jérôme; Jouve, Jean-Luc; Ilharreborde, Brice; Blondel, Benjamin; Accadbled, Franck; Mazda, Keyvan

    2014-07-01

    The Universal Clamp (UC) equipped with a soft sublaminar band is a relatively new thoracic anchor that can be used in hybrid constructs. A dedicated reduction tool that applies traction to the sublaminar band permits gentle translation of the thoracic curve to the pre-contoured fusion rods, which have been previously anchored distally by pedicle screws and proximally by hooks in a claw configuration. A literature review concerning the use of UC in adolescent idiopathic Scoliosis was performed. The results confirm the efficacy with the UC hybrid constructs, the good correction (71-66%) of the main thoracic curve and low loss of correction at 2-year follow-up (3-4%). The thoracic curve correction achieved and maintained in the AIS patients appears to be substantially higher than that reported for all hook and hook hybrid techniques. Regardless of the deformity correcting method employed with all-screw constructs, the Cobb angle correction achieved is equivalent to that achieved with UC hybrid devices. Among the present AIS patients who had normal values of thoracic kyphosis pre-operatively, there was almost no change in average thoracic kyphosis at the latest follow-up. However, among the patients with low pre-operative values of T5-T12 kyphosis, the average T5-T12 kyphosis improved. Hybrid construct with UC is safe, with reduced operative time and blood loss. While achieving deformity correction in the coronal and axial planes equivalent to the best-reported results of all screw or previous hybrid constructs, the UC hybrid technique appears to provide superior correction in the sagittal plane. The excellent outcome is maintained at the 2-year follow-up.

  7. Optical and electrical characterizations of a single step ion beam milling mesa devices of chloride passivated PbS colloidal quantum dots based film

    Energy Technology Data Exchange (ETDEWEB)

    Hechster, Elad, E-mail: elad.hechster@gmail.com; Sarusi, Gabby [Electro-Optics Engineering Unit and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 84100 Israel (Israel); Shapiro, Arthur; Lifshitz, Efrat [Schulich Faculty of Chemistry, Solid State Institute, Russel Berrie Nanotechnology Institute, Technion – Israel Institute of technology, 32000 Haifa (Israel)

    2016-07-15

    Colloidal Quantum Dots (CQDs) are of increasing interest, thanks to their quantum size effect that gives rise to their usage in various applications, such as biological tagging, solar cells and as the sensitizing layer of night vision devices. Here, we analyze the optical absorbance of chloride passivated PbS CQDs as well as revealing a correlation between their photoluminescence and sizes distribution, using theoretical models and experimental results from the literature. Next, we calculate the CQDs resistivity as a film. Although resistivity can be calculated from sheet resistance measurement using four point probes, such measurement is usually carried-out on the layer’s surface that in most cases has dangling bonds and surface states, which might affect the charges flow and modify the resistivity. Therefore; our approach, which was applied in this work, is to extract the actual resistivity from measurements that are performed along the film’s thickness (z-direction). For this intent, we fabricated gold capped PbS mesas devices using a single step Ion Beam Milling (IBM) process where we milled the gold and the PbS film continually, and then measured the vertical resistance. Knowing the mesas’ dimensions, we calculate the resistivity. To the best of our knowledge, no previous work has extracted, vertically, the resistivity of chloride passivated PbS CQDs using the above method.

  8. Site-specific forest-assembly of single-wall carbon nanotubes on electron-beam patterned SiOx/Si substrates

    International Nuclear Information System (INIS)

    Wei Haoyan; Kim, Sang Nyon; Kim, Sejong; Huey, Bryan D.; Papadimitrakopoulos, Fotios; Marcus, Harris L.

    2008-01-01

    Based on electron-beam direct writing on the SiO x /Si substrates, favorable absorption sites for ferric cations (Fe 3+ ions) were created on the surface oxide layer. This allowed Fe 3+ -assisted self-assembled arrays of single-wall carbon nanotube (SWNT) probes to be produced. Auger investigation indicated that the incident energetic electrons depleted oxygen, creating more dangling bonds around Si atoms at the surface of the SiO x layer. This resulted in a distinct difference in the friction forces from unexposed regions as measured by lateral force microscopy (LFM). Atomic force microscopy (AFM) affirmed that the irradiated domains absorbed considerably more Fe 3+ ions upon immersion into pH 2.2 aqueous FeCl 3 solution. This rendered a greater yield of FeO(OH)/FeOCl precipitates, primarily FeO(OH), upon subsequent washing with lightly basic dimethylformamide (DMF) solution. Such selective metal-functionalization established the basis for the subsequent patterned forest-assembly of SWNTs as demonstrated by resonance Raman spectroscopy

  9. Proposal for a Full-Scale Prototype Single-Phase Liquid Argon Time Projection Chamber and Detector Beam Test at CERN

    CERN Document Server

    Kutter, T

    2015-01-01

    The Deep Underground Neutrino Experiment (DUNE) will use a large liquid argon (LAr) detector to measure the CP violating phase, determine the neutrino mass hier- archy and perform precision tests of the three-flavor paradigm in long-baseline neutrino oscillations. The detector will consist of four modules each with a fiducial mass of 10 kt of LAr and due to its unprecedented size will allow sensitive searches for proton decay and the detection and measurement of electron neutrinos from core collapse supernovae [1]. The first 10 kt module will use single-phase LAr detection technique and be itself modular in design. The successful manufacturing, installation and operation of several full-scale detector components in a suitable configuration represents a critical engineering milestone prior to the construction and operation of the first full 10 kt DUNE detector module at the SURF underground site. A charged particle beam test of a prototype detector will provide critical calibration measurements as well as inva...

  10. Optical and electrical characterizations of a single step ion beam milling mesa devices of chloride passivated PbS colloidal quantum dots based film

    International Nuclear Information System (INIS)

    Hechster, Elad; Sarusi, Gabby; Shapiro, Arthur; Lifshitz, Efrat

    2016-01-01

    Colloidal Quantum Dots (CQDs) are of increasing interest, thanks to their quantum size effect that gives rise to their usage in various applications, such as biological tagging, solar cells and as the sensitizing layer of night vision devices. Here, we analyze the optical absorbance of chloride passivated PbS CQDs as well as revealing a correlation between their photoluminescence and sizes distribution, using theoretical models and experimental results from the literature. Next, we calculate the CQDs resistivity as a film. Although resistivity can be calculated from sheet resistance measurement using four point probes, such measurement is usually carried-out on the layer’s surface that in most cases has dangling bonds and surface states, which might affect the charges flow and modify the resistivity. Therefore; our approach, which was applied in this work, is to extract the actual resistivity from measurements that are performed along the film’s thickness (z-direction). For this intent, we fabricated gold capped PbS mesas devices using a single step Ion Beam Milling (IBM) process where we milled the gold and the PbS film continually, and then measured the vertical resistance. Knowing the mesas’ dimensions, we calculate the resistivity. To the best of our knowledge, no previous work has extracted, vertically, the resistivity of chloride passivated PbS CQDs using the above method.

  11. Beam-beam phenomenology

    International Nuclear Information System (INIS)

    Teng, L.C.

    1980-01-01

    In colliding beam storage rings the beam collision regions are generally so short that the beam-beam interaction can be considered as a series of evenly spaced non-linear kicks superimposed on otherwise stable linear oscillations. Most of the numerical studies on computers were carried out in just this manner. But for some reason this model has not been extensively employed in analytical studies. This is perhaps because all analytical work has so far been done by mathematicians pursuing general transcendental features of non-linear mechanics for whom this specific model of the specific system of colliding beams is too parochial and too repugnantly physical. Be that as it may, this model is of direct interest to accelerator physicists and is amenable to (1) further simplification, (2) physical approximation, and (3) solution by analogy to known phenomena

  12. Passivation of the surfaces of single crystal gadolinium molybdate (Gd2(MoO4)3) against attack by hydrofluoric acid by inert ion beam irradiation

    International Nuclear Information System (INIS)

    Bhalla, A.; Cross, L.E.; Tongson, L.

    1978-01-01

    The passivation effect from inert ion beam bombardment has been studied on a ferroelectric surface. The mechanism in these materials may have some additional contributions because of the polarization charges of the domains and the dipole effect (ion beam and surface species) on the surfaces. For these studies Gd 2 (MoO 4 ) 3 (GMO) crystals were selected. Two possible mechanisms of passivation of GMO surfaces when bombarded with ion beams are discussed

  13. Nanosecond electric pulses differentially affect inward and outward currents in patch clamped adrenal chromaffin cells.

    Directory of Open Access Journals (Sweden)

    Lisha Yang

    Full Text Available This study examined the effect of 5 ns electric pulses on macroscopic ionic currents in whole-cell voltage-clamped adrenal chromaffin cells. Current-voltage (I-V relationships first established that the early peak inward current was primarily composed of a fast voltage-dependent Na+ current (INa, whereas the late outward current was composed of at least three ionic currents: a voltage-gated Ca2+ current (ICa, a Ca2+-activated K+ current (IK(Ca, and a sustained voltage-dependent delayed rectifier K+ current (IKV. A constant-voltage step protocol was next used to monitor peak inward and late outward currents before and after cell exposure to a 5 ns pulse. A single pulse applied at an electric (E-field amplitude of 5 MV/m resulted in an instantaneous decrease of ~4% in peak INa that then declined exponentially to a level that was ~85% of the initial level after 10 min. Increasing the E-field amplitude to 8 or 10 MV/m caused a twofold greater inhibitory effect on peak INa. The decrease in INa was not due to a change in either the steady-state inactivation or activation of the Na+ channel but instead was associated with a decrease in maximal Na+ conductance. Late outward current was not affected by a pulse applied at 5 MV/m. However, for a pulse applied at the higher E-field amplitudes of 8 and 10 MV/m, late outward current in some cells underwent a progressive ~22% decline over the course of the first 20 s following pulse exposure, with no further decline. The effect was most likely concentrated on ICa and IK(Ca as IKV was not affected. The results of this study indicate that in whole-cell patch clamped adrenal chromaffin cells, a 5 ns pulse differentially inhibits specific voltage-gated ionic currents in a manner that can be manipulated by tuning E-field amplitude.

  14. Commissioning of a proton gantry equipped with dual x-ray imagers and a robotic patient positioner, and evaluation of the accuracy of single-beam image registration for this system

    International Nuclear Information System (INIS)

    Wang, Ning; Ghebremedhin, Abiel; Patyal, Baldev

    2015-01-01

    Purpose: To check the accuracy of a gantry equipped with dual x-ray imagers and a robotic patient positioner for proton radiotherapy, and to evaluate the accuracy and feasibility of single-beam registration using the robotic positioner. Methods: One of the proton treatment rooms at their institution was upgraded to include a robotic patient positioner (couch) with 6 degrees of freedom and dual orthogonal kilovoltage x-ray imaging panels. The wander of the proton beam central axis, the wander of the beamline, and the orthogonal image panel crosswires from the gantry isocenter were measured for different gantry angles. The couch movement accuracy and couch wander from the gantry isocenter were measured for couch loadings of 50–300 lb with couch rotations from 0° to ±90°. The combined accuracy of the gantry, couch, and imagers was checked using a custom-made 30 × 30 × 30 cm 3 Styrofoam phantom with beekleys embedded in it. A treatment in this room can be set up and registered at a setup field location, then moved precisely to any other treatment location without requiring additional image registration. The accuracy of the single-beam registration strategy was checked for treatments containing multiple beams with different combinations of gantry angles, couch yaws, and beam locations. Results: The proton beam central axis wander from the gantry isocenter was within 0.5 mm with gantry rotations in both clockwise (CW) and counterclockwise (CCW) directions. The maximum wander of the beamline and orthogonal imager crosswire centers from the gantry isocenter were within 0.5 and 0.8 mm, respectively, with the gantry rotations in CW and CCW directions. Vertical and horizontal couch wanders from the gantry isocenter were within 0.4 and 1.3 mm, respectively, for couch yaw from 0° to ±90°. For a treatment with multiple beams with different gantry angles, couch yaws, and beam locations, the measured displacements of treatment beam locations from the one based on the

  15. Health-Related Quality of Life After Single-Fraction High-Dose-Rate Brachytherapy and Hypofractionated External Beam Radiotherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Morton, Gerard C.; Loblaw, D. Andrew; Chung, Hans; Tsang, Gail; Sankreacha, Raxa; Deabreu, Andrea; Zhang Liying; Mamedov, Alexandre; Cheung, Patrick; Batchelar, Deidre; Danjoux, Cyril; Szumacher, Ewa

    2011-01-01

    Purpose: To investigate the change in health-related quality of life for men after high-dose-rate brachytherapy and external beam radiotherapy for prostate cancer and the factors associated with this change. Methods and Materials: Eligible patients had clinically localized intermediate-risk prostate cancer. The patients received high-dose-rate brachytherapy as a single 15-Gy implant, followed by external beam radiotherapy to 37.5 Gy in 15 fractions. The patients were monitored prospectively for toxicity (Common Terminology Criteria for Adverse Events, version 3.0) and health-related quality of life (Expanded Prostate Cancer Index Composite [EPIC]). The proportion of patients developing a clinically significant difference in the EPIC domain score (minimally important difference of >0.5 standard deviation) was determined and correlated with the baseline clinical and dosimetric factors. The study accrued 125 patients, with a median follow-up of 24 months. Results: By 24 months, 23% had Grade 2 urinary toxicity and only 5% had Grade 2 bowel toxicity, with no Grade 3 toxicity. The proportion of patients reporting a significant decrease in EPIC urinary, bowel, sexual, and hormonal domain scores was 53%, 51%, 45%, and 40% at 12 months and 57%, 65%, 51%, and 30% at 24 months, respectively. The proportion with a >1 standard deviation decrease in the EPIC urinary, bowel, sexual, and hormonal domain scores was 38%, 36%, 24%, and 20% at 12 months and 46%, 48%, 19%, and 8% at 24 months, respectively. On multivariate analysis, the dose to 10% of the urethra was associated with a decreasing EPIC urinary domain score (p = .0089) and, less strongly (p = .0312) with a decreasing hormonal domain score. No association was found between the prostate volume, bladder dose, or high-dose volume and urinary health-related quality of life. A high baseline International Index of Erectile Function score was associated (p = .0019) with a decreasing sexual domain score. The optimal maximal dose

  16. Comparison of proton therapy treatment planning for head tumors with a pencil beam algorithm on dual and single energy CT images

    Energy Technology Data Exchange (ETDEWEB)

    Hudobivnik, Nace; Dedes, George; Parodi, Katia; Landry, Guillaume, E-mail: g.landry@lmu.de [Department of Medical Physics, Ludwig-Maximilians-University, Munich 85748 (Germany); Schwarz, Florian; Johnson, Thorsten; Sommer, Wieland H. [Institute for Clinical Radiology, Ludwig Maximilians University Hospital Munich, 81377 Munich (Germany); Agolli, Linda [Department of Radiation Oncology, Ludwig-Maximilians-University, Munich 81377, Germany and Radiation Oncology, Sant’ Andrea Hospital, Sapienza University, Rome 00189 (Italy); Tessonnier, Thomas [Department of Medical Physics, Ludwig-Maximilians-University, Munich 85748, Germany and Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Verhaegen, Frank [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht 6229 ET, the Netherlands and Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec H3A 0G4 (Canada); Thieke, Christian; Belka, Claus [Department of Radiation Oncology, Ludwig-Maximilians-University, Munich 81377 (Germany)

    2016-01-15

    Purpose: Dual energy CT (DECT) has recently been proposed as an improvement over single energy CT (SECT) for stopping power ratio (SPR) estimation for proton therapy treatment planning (TP), thereby potentially reducing range uncertainties. Published literature investigated phantoms. This study aims at performing proton therapy TP on SECT and DECT head images of the same patients and at evaluating whether the reported improved DECT SPR accuracy translates into clinically relevant range shifts in clinical head treatment scenarios. Methods: Two phantoms were scanned at a last generation dual source DECT scanner at 90 and 150 kVp with Sn filtration. The first phantom (Gammex phantom) was used to calibrate the scanner in terms of SPR while the second served as evaluation (CIRS phantom). DECT images of five head trauma patients were used as surrogate cancer patient images for TP of proton therapy. Pencil beam algorithm based TP was performed on SECT and DECT images and the dose distributions corresponding to the optimized proton plans were calculated using a Monte Carlo (MC) simulation platform using the same patient geometry for both plans obtained from conversion of the 150 kVp images. Range shifts between the MC dose distributions from SECT and DECT plans were assessed using 2D range maps. Results: SPR root mean square errors (RMSEs) for the inserts of the Gammex phantom were 1.9%, 1.8%, and 1.2% for SECT phantom calibration (SECT{sub phantom}), SECT stoichiometric calibration (SECT{sub stoichiometric}), and DECT calibration, respectively. For the CIRS phantom, these were 3.6%, 1.6%, and 1.0%. When investigating patient anatomy, group median range differences of up to −1.4% were observed for head cases when comparing SECT{sub stoichiometric} with DECT. For this calibration the 25th and 75th percentiles varied from −2% to 0% across the five patients. The group median was found to be limited to 0.5% when using SECT{sub phantom} and the 25th and 75th percentiles

  17. Displacement sensing based on resonant frequency monitoring of electrostatically actuated curved micro beams

    International Nuclear Information System (INIS)

    Krakover, Naftaly; Krylov, Slava; Ilic, B Robert

    2016-01-01

    The ability to control nonlinear interactions of suspended mechanical structures offers a unique opportunity to engineer rich dynamical behavior that extends the dynamic range and ultimate device sensitivity. We demonstrate a displacement sensing technique based on resonant frequency monitoring of curved, doubly clamped, bistable micromechanical beams interacting with a movable electrode. In this configuration, the electrode displacement influences the nonlinear electrostatic interactions, effective stiffness and frequency of the curved beam. Increased sensitivity is made possible by dynamically operating the beam near the snap-through bistability onset. Various in-plane device architectures were fabricated from single crystal silicon and measured under ambient conditions using laser Doppler vibrometry. In agreement with the reduced order Galerkin-based model predictions, our experimental results show a significant resonant frequency reduction near critical snap-through, followed by a frequency increase within the post-buckling configuration. Interactions with a stationary electrode yield a voltage sensitivity up to  ≈560 Hz V −1 and results with a movable electrode allow motion sensitivity up to  ≈1.5 Hz nm −1 . Our theoretical and experimental results collectively reveal the potential of displacement sensing using nonlinear interactions of geometrically curved beams near instabilities, with possible applications ranging from highly sensitive resonant inertial detectors to complex optomechanical platforms providing an interface between the classical and quantum domains. (paper)

  18. The effect of thermal de-phasing on the beam quality of a high-power single-pass second harmonic generation

    Science.gov (United States)

    Sadat Hashemi, Somayeh; Ghavami Sabouri, Saeed; Khorsandi, Alireza

    2018-04-01

    We present a theoretical model in order to study the effect of a thermally loaded crystal on the quality of a second-harmonic (SH) beam generated in a high-power pumping regime. The model is provided based on using a particular structure of oven considered for MgO:PPsLT nonlinear crystal to compensate for the thermal de-phasing effect that as the pumping power reaches up to 50 W degrades the conversion efficiency and beam quality of the interacting beams. Hereupon, the quality of fundamental beam is involved in the modeling to investigate the final effect on the beam quality of generated SH beam. Beam quality evaluation is subsequently simulated using Hermite-Gaussian modal decomposition approach for a range of fundamental beam qualities varied from 1 to 3 and for different levels of input powers. To provide a meaningful comparison numerical simulation is correlated with real data deduced from a high-power SH generation (SHG) experimental device. It is found that when using the open-top oven scheme and fixing the fundamental M 2-factor at nearly 1, for a range of input powers changing from 15 to 30 W, the M 2-factor of SHG beam is degraded from 9% to 24%, respectively, confirming very good consistency with the reported experimental results.

  19. Prediction of clamp-derived insulin sensitivity from the oral glucose insulin sensitivity index

    DEFF Research Database (Denmark)

    Tura, Andrea; Chemello, Gaetano; Szendroedi, Julia

    2018-01-01

    that underwent both a clamp and an OGTT or meal test, thereby allowing calculation of both the M value and OGIS. The population was divided into a training and a validation cohort (n = 359 and n = 154, respectively). After a stepwise selection approach, the best model for M value prediction was applied......AIMS/HYPOTHESIS: The euglycaemic-hyperinsulinaemic clamp is the gold-standard method for measuring insulin sensitivity, but is less suitable for large clinical trials. Thus, several indices have been developed for evaluating insulin sensitivity from the oral glucose tolerance test (OGTT). However......, most of them yield values different from those obtained by the clamp method. The aim of this study was to develop a new index to predict clamp-derived insulin sensitivity (M value) from the OGTT-derived oral glucose insulin sensitivity index (OGIS). METHODS: We analysed datasets of people...

  20. Gasket-holder to put in place gaskets for connection of pipes with clamp fittings

    International Nuclear Information System (INIS)

    Fiori, R.

    1989-01-01

    Gasket-holder comprising 2 arms with tongues holding the gasket and fixing devices on a pipe clamp fitting and centering means. Application is made to fit circular gaskets on pipe with conic end in adverse environment [fr

  1. space vector pulse width modulation of a multi-level diode clamped

    African Journals Online (AJOL)

    ES Obe

    step by step development of MATLAB /SIMULINK modeling of the space vector ..... Pulse Width Mod. of Multi-Level Diode Clamped Converter 119 powergui. Discrete, .... Load. Figure 22: Block diagram of the three level DCC design. 3 LEVEL ...

  2. Substrate clamping effects on irreversible domain wall dynamics in lead zirconate titanate thin films.

    Science.gov (United States)

    Griggio, F; Jesse, S; Kumar, A; Ovchinnikov, O; Kim, H; Jackson, T N; Damjanovic, D; Kalinin, S V; Trolier-McKinstry, S

    2012-04-13

    The role of long-range strain interactions on domain wall dynamics is explored through macroscopic and local measurements of nonlinear behavior in mechanically clamped and released polycrystalline lead zirconate-titanate (PZT) films. Released films show a dramatic change in the global dielectric nonlinearity and its frequency dependence as a function of mechanical clamping. Furthermore, we observe a transition from strong clustering of the nonlinear response for the clamped case to almost uniform nonlinearity for the released film. This behavior is ascribed to increased mobility of domain walls. These results suggest the dominant role of collective strain interactions mediated by the local and global mechanical boundary conditions on the domain wall dynamics. The work presented in this Letter demonstrates that measurements on clamped films may considerably underestimate the piezoelectric coefficients and coupling constants of released structures used in microelectromechanical systems, energy harvesting systems, and microrobots.

  3. Common voltage eliminating of SVM diode clamping three-level inverter connected to grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    A novel method of common voltage eliminating is put forward for SVM diode clamping three-level inverter connected to grid by calculation of common voltage of its various switching states. PLECS is used to model this three-level inverter connected to grid and good results are obtained. First...... analysis of common mode voltage for switching states of diode clamping 3-level inverter is given in detail. Second the common mode voltage eliminating control strategy of SVM is described for diode clamping three-level inverter. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping...... three-level inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is a very powerful tool to real power circuits modeling. They have also verified that proposed common mode voltage eliminating control strategy of SVM is feasible...

  4. Suppression of Spiral Waves by Voltage Clamp Techniques in a Conductance-Based Cardiac Tissue Model

    International Nuclear Information System (INIS)

    Lian-Chun, Yu; Guo-Yong, Zhang; Yong, Chen; Jun, Ma

    2008-01-01

    A new control method is proposed to control the spatio-temporal dynamics in excitable media, which is described by the Morris–Lecar cells model. It is confirmed that successful suppression of spiral waves can be obtained by spatially clamping the membrane voltage of the excitable cells. The low voltage clamping induces breakup of spiral waves and the fragments are soon absorbed by low voltage obstacles, whereas the high voltage clamping generates travel waves that annihilate spiral waves through collision with them. However, each method has its shortcomings. Furthermore, a two-step method that combines both low and high voltage clamp techniques is then presented as a possible way of out this predicament. (cross-disciplinary physics and related areas of science and technology)

  5. Finite element analysis on factors influencing the clamping force in an electrostatic chuck

    International Nuclear Information System (INIS)

    Wang Xingkuo; Yang Yiyong; Cheng Jia; Wang Kesheng; Sun Yuchun; Cao Minglu; Ji Linhong

    2014-01-01

    As one of the core components of IC manufacturing equipment, the electrostatic chuck (ESC) has been widely applied in semiconductor processing such as etching, PVD and CVD. The clamping force of the ESC is one of the most important technical indicators. A multi-physics simulation software COMSOL is used to analyze the factors influencing the clamping force. The curves between the clamping force and the main parameters such as DC voltage, electrode thickness, electrode radius, dielectric thickness and helium gap are obtained. Moreover, the effects of these factors on the clamping force are investigated by means of orthogonal experiments. The results show that the factors can be ranked in order of voltage, electrode radius, helium gap and dielectric thickness according to their importance, which may offer certain reference for the design of ESCs. (semiconductor devices)

  6. Structural consideration for hot and cold pipe clamps in LMFBR applications

    International Nuclear Information System (INIS)

    Anderson, M.J.; Huang, S.N.; Kappauf, H.; Wagner, S.E.; Wirtz, K.H.

    1983-01-01

    A series of analytical studies are described which evaluate stress levels induced in a 600 mm high temperature, thin-wall sodium pipeline by two alternate clamp designs. The first design consists of a band mounted directly on the pipe and is called the hot clamp. The second design consists of a band mounted using insulation standoffs and is called the cold clamp. Pipe stress levels induced by transient thermal dead weight and seismic loads are discussed. Pipe stress levels and system dynamic spring rates are presented. Procedures utilized to combine clamp induced pipe stress with other short and long term pipe system stresses are detailed. Recommendations for practical application in LMFBR pipe systems are made

  7. Structural considerations for hot and cold pipe clamps in LMFBR applications

    International Nuclear Information System (INIS)

    Anderson, M.J.; Huang, S.N.; Wagner, S.E.; Kappauf, H.; Wirtz, K.H.

    1983-01-01

    A series of analytical studies are described which evaluate stress levels induced in a 600 mm high temperature, thin-wall sodium pipeline by two alternate clamp designs. The first design consists of a band mounted directly on the pipe and is called the hot clamp. The second design consists of a band mounted using insulation standoffs and is called the cold clamp. Pipe stress levels induced by transient thermal dead weight and seismic loads are discussed. Pipe stress levels and system dynamic spring rates are presented. Procedures utilized to combine clamp induced pipe stress with other short and long term pipe system stresses are detailed. Recommendations for practical application in LMFBR pipe systems are made

  8. Patch Clamp: A Powerful Technique for Studying the Mechanism of Acupuncture

    Directory of Open Access Journals (Sweden)

    D. Zhang

    2012-01-01

    Full Text Available Cellular and molecular events can be investigated using electrophysiological techniques. In particular, the patch-clamp method provides detailed information. In addition, the patch-clamp technique has become a powerful method for investigating the mechanisms underlying the effects of acupuncture. In this paper, recent researches on how acupuncture might modulate electrophysiological responses in the central nervous system (CNS and affect peripheral structures are reviewed.

  9. Computer Simulation Model to Train Medical Personnel on Glucose Clamp Procedures.

    Science.gov (United States)

    Maghoul, Pooya; Boulet, Benoit; Tardif, Annie; Haidar, Ahmad

    2017-10-01

    A glucose clamp procedure is the most reliable way to quantify insulin pharmacokinetics and pharmacodynamics, but skilled and trained research personnel are required to frequently adjust the glucose infusion rate. A computer environment that simulates glucose clamp experiments can be used for efficient personnel training and development and testing of algorithms for automated glucose clamps. We built 17 virtual healthy subjects (mean age, 25±6 years; mean body mass index, 22.2±3 kg/m 2 ), each comprising a mathematical model of glucose regulation and a unique set of parameters. Each virtual subject simulates plasma glucose and insulin concentrations in response to intravenous insulin and glucose infusions. Each virtual subject provides a unique response, and its parameters were estimated from combined intravenous glucose tolerance test-hyperinsulinemic-euglycemic clamp data using the Bayesian approach. The virtual subjects were validated by comparing their simulated predictions against data from 12 healthy individuals who underwent a hyperglycemic glucose clamp procedure. Plasma glucose and insulin concentrations were predicted by the virtual subjects in response to glucose infusions determined by a trained research staff performing a simulated hyperglycemic clamp experiment. The total amount of glucose infusion was indifferent between the simulated and the real subjects (85±18 g vs. 83±23 g; p=NS) as well as plasma insulin levels (63±20 mU/L vs. 58±16 mU/L; p=NS). The virtual subjects can reliably predict glucose needs and plasma insulin profiles during hyperglycemic glucose clamp conditions. These virtual subjects can be used to train personnel to make glucose infusion adjustments during clamp experiments. Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

  10. Three Level Diode Clamped Inverter Fed Induction Motor with Dtc-Svm

    OpenAIRE

    V. Ranjith Kumar

    2013-01-01

    This project presents a three-level diode-clamped inverter feeding an asynchronous motor drive with direct torque control (DTC). The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a diode-clamped inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel c...

  11. Modeling CICR in rat ventricular myocytes: voltage clamp studies

    Directory of Open Access Journals (Sweden)

    Palade Philip T

    2010-11-01

    Full Text Available Abstract Background The past thirty-five years have seen an intense search for the molecular mechanisms underlying calcium-induced calcium-release (CICR in cardiac myocytes, with voltage clamp (VC studies being the leading tool employed. Several VC protocols including lowering of extracellular calcium to affect Ca2+ loading of the sarcoplasmic reticulum (SR, and administration of blockers caffeine and thapsigargin have been utilized to probe the phenomena surrounding SR Ca2+ release. Here, we develop a deterministic mathematical model of a rat ventricular myocyte under VC conditions, to better understand mechanisms underlying the response of an isolated cell to calcium perturbation. Motivation for the study was to pinpoint key control variables influencing CICR and examine the role of CICR in the context of a physiological control system regulating cytosolic Ca2+ concentration ([Ca2+]myo. Methods The cell model consists of an electrical-equivalent model for the cell membrane and a fluid-compartment model describing the flux of ionic species between the extracellular and several intracellular compartments (cell cytosol, SR and the dyadic coupling unit (DCU, in which resides the mechanistic basis of CICR. The DCU is described as a controller-actuator mechanism, internally stabilized by negative feedback control of the unit's two diametrically-opposed Ca2+ channels (trigger-channel and release-channel. It releases Ca2+ flux into the cyto-plasm and is in turn enclosed within a negative feedback loop involving the SERCA pump, regulating[Ca2+]myo. Results Our model reproduces measured VC data published by several laboratories, and generates graded Ca2+ release at high Ca2+ gain in a homeostatically-controlled environment where [Ca2+]myo is precisely regulated. We elucidate the importance of the DCU elements in this process, particularly the role of the ryanodine receptor in controlling SR Ca2+ release, its activation by trigger Ca2+, and its

  12. Locoregional Anesthesia for Carotid Endarterectomy: Identification of Patients with Intolerance to Cross-Clamping.

    Science.gov (United States)

    Dellaretti, Marcos; de Vasconcelos, Laura T; Dourado, Jules; de Souza, Renata F; Fontoura, Renato R; de Sousa, Atos A

    2016-03-01

    During carotid endarterectomy (CEA), carotid cross-clamping is performed to allow for artery incision and plaque removal. A small subgroup of patients can tolerate carotid occlusion for only a few seconds, if at all, without presenting neurologic deficit. These patients are described as having ''cross-clamp intolerance.'' The purpose of this study was to demonstrate the safety of locoregional anesthesia in identifying patients with cross-clamp intolerance and factors associated with this condition. From August 2008 to May 2010, 115 consecutive patients were submitted to CEA under locoregional anesthesia at the Santa Casa de Belo Horizonte; the procedure was performed by the main author. Patients who showed intolerance to internal carotid artery (ICA) occlusion for intolerance. Among the 115 participating patients, 9.6% (11 patients) showed intolerance to ICA occlusion and developed deficits in intolerance). The factor that was associated with cross-clamp intolerance was the mean degree of contralateral carotid stenosis, which was 57.5% for those who presented intolerance and 27.8% for those who tolerated ICA occlusion. Locoregional anesthesia is a safe method for identifying patients with cross-clamp intolerance. Patients with cross-clamp intolerance present contralateral stenosis that is greater on average than patients who readily tolerate carotid artery occlusion. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. The Investigation of the Corrosion Resistance of the Tension Clamps Skl14

    Directory of Open Access Journals (Sweden)

    Marek Pětioký

    2015-05-01

    Full Text Available At the level crossings it is possible to find the problems with the corrosion of the parts of the fastening system. These problems are especially at the rubber level crossings and in the tunnels. As a part of the thesis the problem of the corrosion of the tension clamp Skl14 of the producer Vossloh at the rubber level crossings is examined. For the purposes of the comparison the tension clamps without the corrosion protection and the tension clamps with the corrosion protection KTL were examined. As a first step the corrosion features of the tension clamps Skl14 were solved. The examination was divided into two parts. First part it was the examination according to ČSN EN ISO 9227. The samples of the tension clamps were putted into the corrosion chamber. After 1728 h the results of the corrosion impacts were not satisfied. It was decided for the second step of the examination. It was the immersion in an electrolyte solution. As a result of the paper the corrosion features of the tension clamps without the corrosion protection and with the corrosion protection are compared.

  14. Early identification of hERG liability in drug discovery programs by automated patch clamp

    Directory of Open Access Journals (Sweden)

    Timm eDanker

    2014-09-01

    Full Text Available Blockade of the cardiac ion channel coded by hERG can lead to cardiac arrhythmia, which has become a major concern in drug discovery and development. Automated electrophysiological patch clamp allows assessment of hERG channel effects early in drug development to aid medicinal chemistry programs and has become routine in pharmaceutical companies. However, a number of potential sources of errors in setting up hERG channel assays by automated patch clamp can lead to misinterpretation of data or false effects being reported. This article describes protocols for automated electrophysiology screening of compound effects on the hERG channel current. Protocol details and the translation of criteria known from manual patch clamp experiments to automated patch clamp experiments to achieve good quality data are emphasized. Typical pitfalls and artifacts that may lead to misinterpretation of data are discussed. While this article focuses on hERG channel recordings using the QPatch (Sophion A/S, Copenhagen, Denmark technology, many of the assay and protocol details given in this article can be transferred for setting up different ion channel assays by automated patch clamp and are similar on other planar patch clamp platforms.

  15. A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2012-12-01

    Full Text Available In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

  16. Effect of non-ideal clamping shape on the resonance frequencies of silicon nanocantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Guillon, Samuel; Saya, Daisuke; Mazenq, Laurent; Nicu, Liviu [CNRS, LAAS, 7 Avenue du Colonel Roche, F-31077 Toulouse Cedex 4 (France); Perisanu, Sorin; Vincent, Pascal [LPMCN, Universite Claude Bernard Lyon 1 et CNRS, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Lazarus, Arnaud; Thomas, Olivier, E-mail: sguillon@laas.fr [Structural Mechanics and Coupled Systems Laboratory, Conservatoire National des Arts et Metiers, 2 rue Conte, 75003 Paris (France)

    2011-06-17

    In this paper, we investigate the effects of non-ideal clamping shapes on the dynamic behavior of silicon nanocantilevers. We fabricated silicon nanocantilevers using silicon on insulator (SOI) wafers by employing stepper ultraviolet (UV) lithography, which permits a resolution of under 100 nm. The nanocantilevers were driven by electrostatic force inside a scanning electron microscope (SEM). Both lateral and out-of-plane resonance frequencies were visually detected with the SEM. Next, we discuss overhanging of the cantilever support and curvature at the clamping point in the silicon nanocantilevers, which generally arises in the fabrication process. We found that the fundamental out-of-plane frequency of a realistically clamped cantilever is always lower than that for a perfectly clamped cantilever, and depends on the cantilever width and the geometry of the clamping point structure. Using simulation with the finite-elements method, we demonstrate that this discrepancy is attributed to the particular geometry of the clamping point (non-zero joining curvatures and a flexible overhanging) that is obtained in the fabrication process. The influence of the material orthotropy is also investigated and is shown to be negligible.

  17. MEMS-based clamp with a passive hold function for precision position retaining of micro manipulators

    International Nuclear Information System (INIS)

    Brouwer, D M; Van Dijk, J; Soemers, H M J R; De Jong, B R; De Boer, M J; Jansen, H V; Krijnen, G J M

    2009-01-01

    In this paper the design, modeling and fabrication of a precision MEMS-based clamp with a relatively large clamping force are presented. The purpose of the clamp is to mechanically fix a six-degree-of-freedom (DOF) MEMS-based sample manipulator (Brouwer et al J. Int. Soc. Precis. Eng. Nanotechnol. submitted) once the sample has been positioned in all DOFs. The clamping force is generated by a rotational electrostatic comb-drive actuator and can be latched passively by a parallel plate type electrostatically driven locking device. The clamp design is based on the principles of exact constraint design, resulting in a high actuation compliance (flexibility) combined with a high suspension stiffness. Therefore, a relatively large blocking force of 1.4 mN in relation to the used area of 1.8 mm 2 is obtained. The fabrication is based on silicon bulk micromachining technology and combines a high-aspect-ratio deep reactive ion etching (DRIE), conformal deposition of low-pressure chemical vapor deposition (LPCVD) silicon nitride and an anisotropic potassium hydroxide (KOH) backside etching technology. Special attention is given to void reduction of Si x N y trench isolation and reduction of heating phenomena during front-side release etching. Guidelines are given for the applied process. Measurements showed that the clamp was able to fix, hold and release a test actuator. The dynamic behavior was in good agreement with the modal analysis

  18. Failure-free survival following brachytherapy alone or external beam irradiation alone for T1-2 prostate tumors in 2222 patients: results from a single practice

    International Nuclear Information System (INIS)

    Brachman, David G.; Thomas, Theresa; Hilbe, Joseph; Beyer, David C.

    2000-01-01

    Purpose: To evaluate failure-free survival (FFS) for brachytherapy (BT) alone compared to external beam radiotherapy (EBRT) alone for Stage T1-2 Nx-No Mo patients over the same time period by a single community-based practice in the prostate-specific antigen (PSA) era. Materials and Methods: The database of Arizona Oncology Services (a multiphysician radiation oncology practice in the Phoenix metropolitan area) was reviewed for patients meeting the following criteria: (1) T1 or T2 Nx-No Mo prostate cancer; (2) no prior or concurrent therapy including hormones; (3) treatment period 12/88-12/95; and (4) treatment with either EBRT alone or BT alone ( 125 I or 103 Pd). This yielded 1527 EBRT and 695 BT patients; no patients meeting the above criteria were excluded from analysis. Median follow-up for EBRT patients was 41.3 months and, for BT patients, 51.3 months. Patients were not randomized to either therapy but rather received EBRT or BT based upon patient, treating, and/or referring physician preference. PSA failure was defined according to the ASTRO consensus guidelines. The median patient age was 74 years for both groups. Results: Failure-free survival at 5 years for EBRT and BT are 69% and 71%, respectively (p = 0.91). For T stage, no significant difference in FFS at 5 years is observed between EBRT and BT for either T1 (78% vs. 83%, p = 0.47) or T2 (67% vs. 67%, p = 0.89) tumors. Analysis by Gleason score shows superior outcomes for Gleason 8-10 lesions treated with EBRT vs. BT (5-year FFS 52% vs. 28%, p = 0.04); outcomes for lower grade lesions (Gleason 4-6) when analyzed by Gleason score alone do not significantly differ according to treatment received. Patients with initial PSA values of 10-20 ng/dL have an improved FFS with EBRT vs. BT at 5 years (70% vs. 53%, p = 0.001); outcomes for patients with initial PSA ranges of 0-4 ng/dL, of > 4-10 ng/dL, and > 20 ng/dL did not differ significantly by treatment received. FFS was also determined for presenting

  19. Single-Fraction High-Dose-Rate Brachytherapy and Hypofractionated External Beam Radiation Therapy in the Treatment of Intermediate-Risk Prostate Cancer - Long Term Results

    Energy Technology Data Exchange (ETDEWEB)

    Cury, Fabio L., E-mail: fabio.cury@muhc.mcgill.ca [Department of Radiation Oncology, McGill University Health Centre, Montreal, QC (Canada); Duclos, Marie [Department of Radiation Oncology, McGill University Health Centre, Montreal, QC (Canada); Aprikian, Armen [Department of Urology, McGill University Health Centre, Montreal, QC (Canada); Patrocinio, Horacio [Department of Medical Physics, McGill University Health Centre, Montreal, QC (Canada); Kassouf, Wassim [Department of Urology, McGill University Health Centre, Montreal, QC (Canada); Shenouda, George; Faria, Sergio; David, Marc; Souhami, Luis [Department of Radiation Oncology, McGill University Health Centre, Montreal, QC (Canada)

    2012-03-15

    Purpose: We present the long-term results of a cohort of patients with intermediate-risk prostate cancer (PC) treated with single-fraction high-dose-rate brachytherapy (HDRB) combined with hypofractionated external beam radiation therapy (HypoRT). Methods and Materials: Patients were treated exclusively with HDRB and HypoRT. HDRB delivered a dose of 10 Gy to the prostate surface and HypoRT consisted of 50 Gy delivered in 20 daily fractions. The first 121 consecutive patients with a minimum of 2 years posttreatment follow-up were assessed for toxicity and disease control. Results: The median follow-up was 65.2 months. No acute Grade III or higher toxicity was seen. Late Grade II gastrointestinal toxicity was seen in 9 patients (7.4%) and Grade III in 2 (1.6%). Late Grade III genitourinary toxicity was seen in 2 patients (1.6%). After a 24-month follow-up, a rebiopsy was offered to the first 58 consecutively treated patients, and 44 patients agreed with the procedure. Negative biopsies were found in 40 patients (91%). The 5-year biochemical relapse-free survival rate was 90.7% (95% CI, 84.5-96.9%), with 13 patients presenting biochemical failure. Among them, 9 were diagnosed with distant metastasis. Prostate cancer-specific and overall survival rates at 5 years were 100% and 98.8% (95% CI, 96.4-100%), respectively. Conclusion: The combination of HDRB and HypoRT is well tolerated, with acceptable toxicity rates. Furthermore, results from rebiopsies revealed an encouraging rate of local control. These results confirm that the use of conformal RT techniques, adapted to specific biological tumor characteristics, have the potential to improve the therapeutic ratio in intermediate-risk PC patients.

  20. Generalized multi-dimensional adaptive filtering for conventional and spiral single-slice, multi-slice, and cone-beam CT

    International Nuclear Information System (INIS)

    Kachelriess, Marc; Watzke, Oliver; Kalender, Willi A.

    2001-01-01

    In modern computed tomography (CT) there is a strong desire to reduce patient dose and/or to improve image quality by increasing spatial resolution and decreasing image noise. These are conflicting demands since increasing resolution at a constant noise level or decreasing noise at a constant resolution level implies a higher demand on x-ray power and an increase of patient dose. X-ray tube power is limited due to technical reasons. We therefore developed a generalized multi-dimensional adaptive filtering approach that applies nonlinear filters in up to three dimensions in the raw data domain. This new method differs from approaches in the literature since our nonlinear filters are applied not only in the detector row direction but also in the view and in the z-direction. This true three-dimensional filtering improves the quantum statistics of a measured projection value proportional to the third power of the filter size. Resolution tradeoffs are shared among these three dimensions and thus are considerably smaller as compared to one-dimensional smoothing approaches. Patient data of spiral and sequential single- and multi-slice CT scans as well as simulated spiral cone-beam data were processed to evaluate these new approaches. Image quality was assessed by evaluation of difference images, by measuring the image noise and the noise reduction, and by calculating the image resolution using point spread functions. The use of generalized adaptive filters helps to reduce image noise or, alternatively, patient dose. Image noise structures, typically along the direction of the highest attenuation, are effectively reduced. Noise reduction values of typically 30%-60% can be achieved in noncylindrical body regions like the shoulder. The loss in image resolution remains below 5% for all cases. In addition, the new method has a great potential to reduce metal artifacts, e.g., in the hip region

  1. [Analysis of brain hemometabolism behavior during carotid endarterectomy with temporary clamping.].

    Science.gov (United States)

    Duval Neto, Gastão Fernandes; Niencheski, Augusto H

    2004-04-01

    Carotid endarterectomy with temporary clamping changes cerebral blood flow and cerebral metabolic oxygen demand ratio with consequent oligemic hypoxia or hemometabolic uncoupling. This study aimed at identifying changes in brain hemometabolism, evaluated through changes in oxyhemoglobin saturation in internal jugular vein bulb (SvjO2) during carotid endarterectomy with clamping, and at correlating these changes with potentially interfering factors, mainly end tidal CO2 pressure (P ET CO2) and cerebral perfusion pressure (CPP). Sixteen patients with unilateral carotid stenotic disease scheduled to carotid endarterectomy with carotid arterial clamping were enrolled in this study. Parameters including internal jugular bulb oxyhemoglobin saturation, stump pressure and end tidal CO2 pressure were measured at the following moments: M1 - pre-clamping; M2 - 3 minutes after clamping; M3 - pre-unclamping; M4 - post-unclamping). The comparison among SvjO2 (%, mean +/- SD) in all studied periods has shown differences between those recorded in moments M1 (52.25 +/- 7.87) and M2 (47.43 +/- 9.19). This initial decrease stabilized during temporary clamping, showing decrease in the comparison between M2 and M3 (46.56 +/- 9.25), without statistical significance (p = ns). At post-unclamping, M4 (47.68 +/- 9.12), SvjO2 was increased as compared to M2 and M3 clamping stages, however it was still lower than that of pre-clamping stage M1.(M4 x M1 - p brain hemometabolic uncoupling trend were correlated to P ET CO2. The comparison between CPP and SvjO2 showed weak correlation devoid of statistical significance. In the conditions of our study, SvjO2 measurement is a fast and effective way of clinically monitoring changes in CBF/CMRO2 ratio. Temporary carotid clamping implies in a trend towards brain hemometabolic uncoupling and, as a consequence, to oligemic ischemia; cerebral perfusion pressure does not assesses brain hemometabolic status (CBF and CMRO2 ratio); hypocapnia, may lead to

  2. Calorimetric beam-current integrator

    International Nuclear Information System (INIS)

    Osborne, J.L.

    1984-01-01

    A single-cup calorimeter for beam-current integration and its associated electronics are described. The design allows beam power up to 120 W and is shown to integrate with an accuracy of 1% over a range of beam energy, current, and power. (orig.)

  3. A Refined Zigzag Beam Theory for Composite and Sandwich Beams

    Science.gov (United States)

    Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco

    2009-01-01

    A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.

  4. High current beam transport with multiple beam arrays

    International Nuclear Information System (INIS)

    Kim, C.H.

    1985-05-01

    Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed

  5. Parametric Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion

    International Nuclear Information System (INIS)

    Prost, Lionel Robert

    2007-01-01

    The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program that explores heavy-ion beam as the driver option for fusion energy production in an Inertial Fusion Energy (IFE) plant. The HCX is a beam transport experiment at a scale representative of the low-energy end of an induction linear accelerator driver. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density ∼0.2 (micro)C/m) over long pulse durations (4 (micro)s) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K + ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (∼80%) is achieved with acceptable emittance growth and beam loss. We achieved good envelope control, and re-matching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics

  6. Cost-Effectiveness Analysis of Single Fraction of Stereotactic Body Radiation Therapy Compared With Single Fraction of External Beam Radiation Therapy for Palliation of Vertebral Bone Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hayeon, E-mail: kimh2@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Rajagopalan, Malolan S.; Beriwal, Sushil; Huq, M. Saiful [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Smith, Kenneth J. [Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (United States)

    2015-03-01

    Purpose: Stereotactic body radiation therapy (SBRT) has been proposed for the palliation of painful vertebral bone metastases because higher radiation doses may result in superior and more durable pain control. A phase III clinical trial (Radiation Therapy Oncology Group 0631) comparing single fraction SBRT with single fraction external beam radiation therapy (EBRT) in palliative treatment of painful vertebral bone metastases is now ongoing. We performed a cost-effectiveness analysis to compare these strategies. Methods and Materials: A Markov model, using a 1-month cycle over a lifetime horizon, was developed to compare the cost-effectiveness of SBRT (16 or 18 Gy in 1 fraction) with that of 8 Gy in 1 fraction of EBRT. Transition probabilities, quality of life utilities, and costs associated with SBRT and EBRT were captured in the model. Costs were based on Medicare reimbursement in 2014. Strategies were compared using the incremental cost-effectiveness ratio (ICER), and effectiveness was measured in quality-adjusted life years (QALYs). To account for uncertainty, 1-way, 2-way and probabilistic sensitivity analyses were performed. Strategies were evaluated with a willingness-to-pay (WTP) threshold of $100,000 per QALY gained. Results: Base case pain relief after the treatment was assumed as 20% higher in SBRT. Base case treatment costs for SBRT and EBRT were $9000 and $1087, respectively. In the base case analysis, SBRT resulted in an ICER of $124,552 per QALY gained. In 1-way sensitivity analyses, results were most sensitive to variation of the utility of unrelieved pain; the utility of relieved pain after initial treatment and median survival were also sensitive to variation. If median survival is ≥11 months, SBRT cost <$100,000 per QALY gained. Conclusion: SBRT for palliation of vertebral bone metastases is not cost-effective compared with EBRT at a $100,000 per QALY gained WTP threshold. However, if median survival is ≥11 months, SBRT costs ≤$100

  7. Cost-Effectiveness Analysis of Single Fraction of Stereotactic Body Radiation Therapy Compared With Single Fraction of External Beam Radiation Therapy for Palliation of Vertebral Bone Metastases

    International Nuclear Information System (INIS)

    Kim, Hayeon; Rajagopalan, Malolan S.; Beriwal, Sushil; Huq, M. Saiful; Smith, Kenneth J.

    2015-01-01

    Purpose: Stereotactic body radiation therapy (SBRT) has been proposed for the palliation of painful vertebral bone metastases because higher radiation doses may result in superior and more durable pain control. A phase III clinical trial (Radiation Therapy Oncology Group 0631) comparing single fraction SBRT with single fraction external beam radiation therapy (EBRT) in palliative treatment of painful vertebral bone metastases is now ongoing. We performed a cost-effectiveness analysis to compare these strategies. Methods and Materials: A Markov model, using a 1-month cycle over a lifetime horizon, was developed to compare the cost-effectiveness of SBRT (16 or 18 Gy in 1 fraction) with that of 8 Gy in 1 fraction of EBRT. Transition probabilities, quality of life utilities, and costs associated with SBRT and EBRT were captured in the model. Costs were based on Medicare reimbursement in 2014. Strategies were compared using the incremental cost-effectiveness ratio (ICER), and effectiveness was measured in quality-adjusted life years (QALYs). To account for uncertainty, 1-way, 2-way and probabilistic sensitivity analyses were performed. Strategies were evaluated with a willingness-to-pay (WTP) threshold of $100,000 per QALY gained. Results: Base case pain relief after the treatment was assumed as 20% higher in SBRT. Base case treatment costs for SBRT and EBRT were $9000 and $1087, respectively. In the base case analysis, SBRT resulted in an ICER of $124,552 per QALY gained. In 1-way sensitivity analyses, results were most sensitive to variation of the utility of unrelieved pain; the utility of relieved pain after initial treatment and median survival were also sensitive to variation. If median survival is ≥11 months, SBRT cost <$100,000 per QALY gained. Conclusion: SBRT for palliation of vertebral bone metastases is not cost-effective compared with EBRT at a $100,000 per QALY gained WTP threshold. However, if median survival is ≥11 months, SBRT costs ≤$100

  8. High intensity beam dump for the Tevatron beam abort system

    International Nuclear Information System (INIS)

    Kidd, J.; Mokhov, N.; Murphy, T.; Palmer, M.; Toohig, T.; Turkot, F.; VanGinneken, A.

    1981-01-01

    The beam abort system proposed for the Fermilab Tevatron Accelerator will extract the proton beam from the ring in a single turn (approximately 20/mu/s) and direct it to an external beam dump. It is the function of the beam dump to absorb the unwanted beam and limit the escaping radiation to levels that are acceptable to the surrounding populace and apparatus. A beam dump that is expected to meet these requirements has been designed and constructed. Detailed design of the dump, including considerations leading to the choice of materials, are given. 6 refs

  9. Beam-beam studies for FCC-hh

    CERN Document Server

    AUTHOR|(CDS)2068329; Pieloni, Tatiana; Buffat, Xavier; Furuseth, Sondre Vik

    2017-01-01

    The Future Circular Collider hadron-hadron (FCC-hh) design study is currently exploring different IR design possibilities including round and flat optics or different crossing schemes. The present study intends to evaluate each scenario from the beam-beam effects point of view. In particular the single particle long term stability to maximize beam lifetimes and luminosity reach is used to quantify the differences. The impact of strong head on interactions on the beam quality and lifetime is addressed by means of GPU accelerated simulations code featuring a weak-strong 6-dimensional beam-beam interaction.

  10. Craft Stick Beams

    Science.gov (United States)

    Karplus, Alan K.

    1996-01-01

    The objective of this exercise is to provide a phenomenological 'hands-on' experience that shows how geometry can affect the load carrying capacity of a material used in construction, how different materials have different failure characteristics, and how construction affects the performance of a composite material. This will be accomplished by building beams of a single material and composite beams of a mixture of materials (popsicle sticks, fiberboard sheets, and tongue depressors); testing these layered beams to determine how and where they fail; and based on the failure analysis, designing a layered beam that will fail in a predicted manner. The students will learn the effects of lamination, adhesion, and geometry in layered beam construction on beam strength and failure location.

  11. Vibration and instability of a viscous-fluid-conveying single-walled carbon nanotube embedded in a visco-elastic medium

    International Nuclear Information System (INIS)

    Soltani, P; Farshidianfar, A; Taherian, M M

    2010-01-01

    In this study, for the first time, the transverse vibrational model of a viscous-fluid-conveying single-walled carbon nanotube (SWCNT) embedded in biological soft tissue is developed. Nonlocal Euler-Bernoulli beam theory has been used to investigate fluid-induced vibration of the SWCNT while visco-elastic behaviour of the surrounding tissue is simulated by the Kelvin-Voigt model. The results indicate that the resonant frequencies and the critical flow velocity at which structural instability of nanotubes emerges are significantly dependent on the properties of the medium around the nanotube, the boundary conditions, the viscosity of the fluid and the nonlocal parameter. Detailed results are demonstrated for the dependence of damping and elastic properties of the medium on the resonant frequencies and the critical flow velocity. Three standard boundary conditions, namely clamped-clamped, clamped-pinned and pinned-pinned, are applied to study the effect of the supported end conditions. Furthermore, it is found that the visco-elastic foundation causes an obvious reduction in the critical velocity in comparison with the elastic foundation, in particular for a compliant medium, pinned-pinned boundary condition, high viscosity of the fluid and small values of the nonlocal coefficient.

  12. Do We Need to Clamp the Renal Hilum Liberally during the Initial Phase of the Learning Curve of Robot-Assisted Nephron-Sparing Surgery?

    Directory of Open Access Journals (Sweden)

    Ömer Acar

    2014-01-01

    Full Text Available Objective. We aimed to compare the results of our initial robot-assisted nephron-sparing surgeries (RANSS performed with or without hilar clamping. Material and Method. Charts of the initial RANSSs (n=44, which were performed by a single surgeon, were retrospectively reviewed. R.E.N.A.L. nephrometry system, modified Clavien classification, and M.D.R.D. equation were used to record tumoral complexity, complications, and estimated glomerular filtration rate (eGFR, respectively. Outcomes of the clamped (group 1, n=14 versus off-clamp (group 2, n=30 RANSSs were compared. Results. The difference between the two groups was insignificant regarding mean patient age, mean tumor size, and mean R.E.N.A.L. nephrometry score. Mean operative time, mean estimated blood loss amount, and mean length of hospitalization were similar between groups. A total of 4 patients in each group suffered 11 Clavien grade ≥2 complications early postoperatively. Open conversion rates were similar. The difference between the 2 groups in terms of the mean postoperative change in eGFR was insignificant. We did not encounter any local recurrence after a mean follow-up of 18.9 months. Conclusions. Creating warm-ischemic conditions during RANSS should not be a liberal decision, even in the initial phases of the learning curve for a highly experienced open surgeon.

  13. Orthogonal image pairs coupled with OSMS for noncoplanar beam angle, intracranial, single-isocenter, SRS treatments with multiple targets on the Varian Edge radiosurgery system

    Directory of Open Access Journals (Sweden)

    Jasmine A. Oliver, PhD

    2017-07-01

    Conclusion: Based on our study, CR-induced shifts with the Varian Edge radiosurgery system will not produce noticeable dosimetric effects for SRS treatments. Thus, replacing cone beam CT with orthogonal kV/kV pairs coupled with OSMS at the treatment couch angle could reduce the number of cone beam CT scans that are acquired during a standard SRS treatment while providing an accurate and safe treatment with negligible dosimetric effects on the treatment plan.

  14. How to measure load-dependent kinetics of individual motor molecules without a force clamp

    DEFF Research Database (Denmark)

    Sung, J.; Mortensen, Kim; Spudich, J.A.

    2017-01-01

    Single-molecule force spectroscopy techniques, including optical trapping, magnetic trapping, and atomic force microscopy, have provided unprecedented opportunities to understand biological processes at the smallest biological length scales. For example, they have been used to elucidate the molec......Single-molecule force spectroscopy techniques, including optical trapping, magnetic trapping, and atomic force microscopy, have provided unprecedented opportunities to understand biological processes at the smallest biological length scales. For example, they have been used to elucidate...... functions at the single molecule level, such as conformational changes and force-generation of individual motor proteins or force-dependent kinetics in molecular interactions. Here, we describe a new method, “Harmonic Force Spectroscopy (HFS).” With a conventional dual-beam optical trap and a simple...... concepts, experimental setup, step-by-step experimental protocol, theory, data analysis, and results....

  15. Clampe de Ganz no tratamento de urgência em lesões do anel pélvico Ganz clamps to treat emergencies in pelvic ring lesions

    Directory of Open Access Journals (Sweden)

    Gilberto José Cação Pereira

    2008-07-01

    Full Text Available OBJETIVO: Avaliar a eficiência do clampe de Ganz na estabilização e redução dos deslocamentos da pelve, quando utilizado no tratamento de urgência, além de aquilatar eventuais dificuldades e facilidades do método. MÉTODOS: O clampe de Ganz foi utilizado no tratamento de urgência em 31 pacientes com graves lesões do anel pélvico (Tile C associadas a importante instabilidade hemodinâmica. RESULTADO: Entre os pacientes, 27 (87,1% apresentaram evolução favorável, com estabilização, redução dos deslocamentos e compressão da região posterior do anel, além de estabilização hemodinâmica, e quatro (12,9% evoluíram para óbito. CONCLUSÃO: O clampe de Ganz mostrou-se eficiente ferramenta no tratamento de urgência das lesões do anel pélvico, por ser de concepção simples, de rápida colocação, não impedir ou dificultar procedimentos no abdome e, principalmente, por permitir a estabilização da pelve, redução dos deslocamentos e compressão na região posterior do anel, local onde ocorrem os maiores sangramentos, reduzindo-os ou eliminando-os.OBJECTIVE: To evaluate the effectiveness of Ganz clamp to stabilize and reduce pelvic dislocations in emergency situations, and to assess possible difficult and easy aspects of the method. METHOD: Ganz clamp was used in the emergency treatment of 31 patients with severe lesions of the pelvic ring (Tile C associated to major hemodynamic instability. RESULTS: Among the patients, 27 (87.1% presented a favorable evolution, with stabilization, reduction of dislocations, and compression of the posterior portion of the ring, and also hemodynamic stabilization, and 4 (12.9% died. CONCLUSION: The Ganz clamp was found to be an effective tool in the emergency treatment of pelvic ring lesions because it has an uncomplicated conception, allowing for a fast placement, because it does not prevent nor make it difficult for abdominal procedures, and most of all because it allows for the

  16. Holographic memory using beam steering

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Hanan, Jay C. (Inventor); Reyes, George F. (Inventor); Zhou, Hanying (Inventor)

    2006-01-01

    A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) or Micro-Electro-Mechanical Systems (MEMS) mirrors steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

  17. Implementation of a fast 16-Bit dynamic clamp using LabVIEW-RT.

    Science.gov (United States)

    Kullmann, Paul H M; Wheeler, Diek W; Beacom, Joshua; Horn, John P

    2004-01-01

    The dynamic-clamp method provides a powerful electrophysiological tool for creating virtual ionic conductances in living cells and studying their influence on membrane potential. Here we describe G-clamp, a new way to implement a dynamic clamp using the real-time version of the Lab-VIEW programming environment together with a Windows host, an embedded microprocessor that runs a real-time operating system and a multifunction data-acquisition board. The software includes descriptions of a fast voltage-dependent sodium conductance, delayed rectifier, M-type and A-type potassium conductances, and a leak conductance. The system can also read synaptic conductance waveforms from preassembled data files. These virtual conductances can be reliably implemented at speeds < or =43 kHz while simultaneously saving two channels of data with 16-bit precision. G-clamp also includes utilities for measuring current-voltage relations, synaptic strength, and synaptic gain. Taking an approach built on a commercially available software/hardware platform has resulted in a system that is easy to assemble and upgrade. In addition, the graphical programming structure of LabVIEW should make it relatively easy for others to adapt G-clamp for new experimental applications.

  18. Forced vibrations of a cantilever beam

    International Nuclear Information System (INIS)

    Repetto, C E; Roatta, A; Welti, R J

    2012-01-01

    The theoretical and experimental solutions for vibrations of a vertical-oriented, prismatic, thin cantilever beam are studied. The beam orientation is ‘downwards’, i.e. the clamped end is above the free end, and it is subjected to a transverse movement at a selected frequency. Both the behaviour of the device driver and the beam's weak-damping resonance response are compared for the case of an elastic beam made from PVC plastic excited over a frequency range from 1 to 30 Hz. The current analysis predicts the presence of ‘pseudo-nodes’ in the normal modes of oscillation. It is important to note that our results were obtained using very simple equipment, present in the teaching laboratory. (paper)

  19. Modelling the clamping force distribution among chips in press-pack IGBTs using the finite element method

    DEFF Research Database (Denmark)

    Hasmasan, Adrian Augustin; Busca, Christian; Teodorescu, Remus

    2012-01-01

    In this paper, a FEM (finite element method) based mechanical model for PP (press-pack) IGBTs (insulated gate bipolar transistors) is presented, which can be used to calculate the clamping force distribution among chips under various clamping conditions. The clamping force is an important parameter...... for the chip, because it influences contact electrical resistance, contact thermal resistance and power cycling capability. Ideally, the clamping force should be equally distributed among chips, in order to maximize the reliability of the PP IGBT. The model is built around a hypothetical PP IGBT with 9 chips......, and it has numerous simplifications in order to reduce the simulation time as much as possible. The developed model is used to analyze the clamping force distribution among chips, in various study cases, where uniform and non-uniform clamping pressures are applied on the studied PP IGBT....

  20. Coherent beam-beam effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1992-01-01

    There are two physical pictures that describe the beam-beam interaction in a storage ring collider: The weak-strong and the strong-strong pictures. Both pictures play a role in determining the beam-beam behavior. This review addresses only the strong-strong picture. The corresponding beam dynamical effects are referred to as the coherent beam-beam effects. Some basic knowledge of the weak-strong picture is assumed. To be specific, two beams of opposite charges are considered. (orig.)

  1. A summary of some beam-beam models

    International Nuclear Information System (INIS)

    Chao, A.W.

    1989-01-01

    Two categories of theoretical models for the beam-beam interaction are reviewed: the linear-lens models and the single-resonance models. In a linear-lens model, the beam-beam force is linearized and represented by a localized linear lens. Analyses of incoherent single particle effects can be performed exactly in these models by using matrix techniques. Although the results do not agree with the experimental observations in many respects, the linear-lens models constitute a starting point of our understanding of the beam-beam interaction. In the single-resonance models, one is concerned with the possible incoherent instabilities as the betatron tune of some of the particles is close to a certain rational number. It is assumed in these models that one and only one such rational number dominates the single-particle beam-beam effects. It is found that static single resonances cannot explain many of the experimental results. Some attempts have been made to modify the static single-resonance theory by including some mechanisms for diffusive tune fluctuations or periodic tune modulations. These modified single-resonance models have met only with some limited qualitative success. 21 refs., 13 figs

  2. Enhancing endogenous stem cells in the newbornvia delayed umbilical cord clamping

    Institute of Scientific and Technical Information of China (English)

    Christopher Lawton; Sandra Acosta; Nate Watson; Chiara Gonzales-Portillo; hTeo Diamandis; Naoki Tajiri; Yuji Kaneko; Paul R. Sanberg; Cesar V. Borlongan

    2015-01-01

    There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal beneifts including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deifciency anemia in term infants. Human umbilical cord blood con-tains signiifcant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it en-hances blood lfow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant’s susceptibility to both neonatal and age-related diseases.

  3. Artifactual voltage response recorded from hair cells with patch-clamp amplifiers.

    Science.gov (United States)

    Masetto, S; Weng, T; Valli, P; Correia, M J

    1999-06-23

    Patch-clamp amplifiers (PCAs) are commonly used to characterize voltage- and current-clamp responses in the same cell. However, the cell membrane voltage response can be severely distorted by PCAs working in the current-clamp mode. Here we compare the voltage response of pigeon semicircular canal hair cells in situ, recorded with two different PCAs, and with a classic microelectrode bridge amplifier (BA). We found that the voltage response of hair cells recorded with PCAs differed significantly from that recorded with the BA. The true hair cell membrane voltage response to positive current steps was characterized by a strongly damped oscillation, whose frequency and duration depended on hair cell location in the sensory crista ampullaris.

  4. The evaluation on clamping force of high strength bolts by length parameter

    International Nuclear Information System (INIS)

    Kim, Kang-Seok; Nah, Hwan-Seon; Lee, Hyeon-Ju; Lee, Kang-Min

    2009-01-01

    It has been reported that the length parameter of high strength bolts results in the variance in tension loads. The required turn for each length is specified in AISC RCSC specification. This study was focused on evaluating any influence on the clamping torque subjected to length parameter of high strength bolts. The two kinds of high strength bolts of specimen are as follows; High Strength Hexagon bolt defined on ASTM A490 and Torque Shear Bolt on KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut and the clamping force were analyzed to review whether length parameter can be affected on the required tension load. To test whether the length parameter has an impact on the torque and turn of nut for the required strength and clamping force, statistical analysis is carried out. (author)

  5. Flange joint system for SRF cavities utilizing high force spring clamps for low particle generation

    Science.gov (United States)

    None

    2017-09-05

    A flange joint system for SRF cavities. The flange joint system includes a set of high force spring clamps that produce high force on the simple flanges of Superconducting Radio Frequency (SRF) cavities to squeeze conventional metallic seals. The system establishes the required vacuum and RF-tight seal with minimum particle contamination to the inside of the cavity assembly. The spring clamps are designed to stay within their elastic range while being forced open enough to mount over the flange pair. Upon release, the clamps have enough force to plastically deform metallic seal surfaces and continue to a new equilibrium sprung dimension where the flanges remain held against one another with enough preload such that normal handling will not break the seal.

  6. Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping

    Directory of Open Access Journals (Sweden)

    Christopher Lawton

    2015-01-01

    Full Text Available There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant′s susceptibility to both neonatal and age-related diseases.

  7. The Anion Paradox in Sodium Taste Reception: Resolution by Voltage-Clamp Studies

    Science.gov (United States)

    Ye, Qing; Heck, Gerard L.; Desimone, John A.

    1991-11-01

    Sodium salts are potent taste stimuli, but their effectiveness is markedly dependent on the anion, with chloride yielding the greatest response. The cellular mechanisms that mediate this phenomenon are not known. This "anion paradox" has been resolved by considering the field potential that is generated by restricted electrodiffusion of the anion through paracellular shunts between taste-bud cells. Neural responses to sodium chloride, sodium acetate, and sodium gluconate were studied while the field potential was voltage-clamped. Clamping at electronegative values eliminated the anion effect, whereas clamping at electropositive potentials exaggerated it. Thus, field potentials across the lingual epithelium modulate taste reception, indicating that the functional unit of taste reception includes the taste cell and its paracellular microenvironment.

  8. Investigating the effect of clamping force on the fatigue life of bolted plates using volumetric approach

    International Nuclear Information System (INIS)

    Esmaeili, F.; Chakherlou, T. N.; Zehsaz, M.; Hasanifard, S.

    2013-01-01

    In this paper, the effects of bolt clamping force on the fatigue life for bolted plates made from Al7075-T6 have been studied on the values of notch strength reduction factor obtained by volumetric approach. To attain stress distribution around the notch (hole) which is required for volumetric approach, nonlinear finite element simulations were carried out. To estimate the fatigue life, the available smooth S-N curve of Al7075-T6 and the notch strength reduction factor obtained from volumetric method were used. The estimated fatigue life was compared with the available experimental test results. The investigation shows that there is a good agreement between the life predicted by the volumetric approach and the experimental results for various specimens with different amount of clamping forces. Volumetric approach and experimental results showed that the fatigue life of bolted plates improves because of the compressive stresses created around the plate hole due to clamping force.

  9. Analysis and testing of the DIII-D ohmic heating coil lead repair clamp

    International Nuclear Information System (INIS)

    Reis, E.E.; Anderson, P.M.; Chin, E.; Robinson, J.I.

    1997-11-01

    DIII-D has been operating for the last year with limited volt-second capabilities due to structural failure of a conductor lead to one of the ohmic heating (OH) solenoids. The conductor failure was due to poor epoxy impregnation of the overwrap of the lead pack, resulting in copper fatigue and a water leak. A number of structural analyses were performed to assist in determining the failure scenario and to evaluate various repair options. A fatigue stress analysis of the leads with a failed epoxy overwrap indicated crack initiation after 1,000 cycles at the maximum operating conditions. The failure occurred in a very inaccessible area which restricted design repair options to concepts which could be implemented remotely. Several design options were considered for repairing the lead so that it can sustain the loads for 7.5 Vs conditions at full toroidal field. A clamp, along with preloaded banding straps and shim bags, provides a system that guarantees that the stress at the crack location is always compressive and prevents further crack growth in the conductor. Due to the limited space available for the repair, it was necessary to design the clamp system to operate at the material yield stress. The primary components of the clamp system were verified by load tests prior to installation. The main body of the clamp contains a load cell and potentiometer for monitoring the load-deflection characteristics of the clamp and conductors during plasma operation. Strain gages provides redundant instrumentation. If required, the preload on the conductors can be increased remotely by a special wrench attached to the clamp assembly

  10. Combined acute hyperglycemic and hyperinsulinemic clamp induced profibrotic and proinflammatory responses in the kidney.

    Science.gov (United States)

    Mariappan, Meenalakshmi M; DeSilva, Kristin; Sorice, Gian Pio; Muscogiuri, Giovanna; Jimenez, Fabio; Ahuja, Seema; Barnes, Jefferey L; Choudhury, Goutam Ghosh; Musi, Nicolas; DeFronzo, Ralph; Kasinath, Balakuntalam S

    2014-02-01

    Increase in matrix protein content in the kidney is a cardinal feature of diabetic kidney disease. While renal matrix protein content is increased by chronic hyperglycemia, whether it is regulated by acute elevation of glucose and insulin has not been addressed. In this study, we aimed to evaluate whether short duration of combined hyperglycemia and hyperinsulinemia, mimicking the metabolic environment of prediabetes and early type 2 diabetes, induces kidney injury. Normal rats were subjected to either saline infusion (control, n = 4) or 7 h of combined hyperglycemic-hyperinsulinemic clamp (HG+HI clamp; n = 6). During the clamp, plasma glucose and plasma insulin were maintained at about 350 mg/dl and 16 ng/ml, respectively. HG+HI clamp increased the expression of renal cortical transforming growth factor-β (TGF-β) and renal matrix proteins, laminin and fibronectin. This was associated with the activation of SMAD3, Akt, mammalian target of rapamycin (mTOR) complexes, and ERK signaling pathways and their downstream target events in the initiation and elongation phases of mRNA translation, an important step in protein synthesis. Additionally, HG+HI clamp provoked renal inflammation as shown by the activation of Toll-like receptor 4 (TLR4) and infiltration of CD68-positive monocytes. Urinary F2t isoprostane excretion, an index of renal oxidant stress, was increased in the HG+HI clamp rats. We conclude that even a short duration of hyperglycemia and hyperinsulinemia contributes to activation of pathways that regulate matrix protein synthesis, inflammation, and oxidative stress in the kidney. This finding could have implications for the control of short-term rises in blood glucose in diabetic individuals at risk of developing kidney disease.

  11. Modeling error and apparent isotope discrimination confound estimation of endogenous glucose production during euglycemic glucose clamps

    International Nuclear Information System (INIS)

    Finegood, D.T.; Bergman, R.N.; Vranic, M.

    1988-01-01

    We previously demonstrated that conventional tracer methods applied to euglycemic-hyperinsulinemic glucose clamps result in substantially negative estimates for the rate of endogenous glucose production, particularly during the first half of 180-min clamps. We also showed that addition of tracer to the exogenous glucose infusate resulted in nonnegative endogenous glucose production (Ra) estimates. In this study, we investigated the underlying cause of negative estimates of Ra from conventional clamp/tracer methods and the reason for the difference in estimates when tracer is added to the exogenous glucose infusate. We performed euglycemic-hyperinsulinemic (300-microU/ml) clamps in normal dogs without (cold GINF protocol, n = 6) or with (hot GINF protocol, n = 6) tracer (D-[3-3H]glucose) added to the exogenous glucose infusate. In the hot GINF protocol, sufficient tracer was added to the exogenous glucose infusate such that arterial plasma specific activity (SAa) did not change from basal through the clamp period (P greater than .05). In the cold GINF studies, plasma SAa fell 81 +/- 2% from the basal level by the 3rd h of clamping. We observed a significant, transient, positive venous-arterial difference in specific activity (SAv-SAa difference) during the cold GINF studies. The SAv-SAa difference reached a peak of 27 +/- 6% at 30 min and diminished to a plateau of 7 +/- 1% between 70 and 180 min. We also observed a positive but constant SAv-SAa difference (4.6 +/- 0.2% between 10 and 180 min) during the hot GINF studies

  12. Timing of umbilical cord-clamping and infant anaemia: the role of maternal anaemia.

    Science.gov (United States)

    Blouin, Brittany; Penny, Mary E; Maheu-Giroux, Mathieu; Casapía, Martín; Aguilar, Eder; Silva, Hermánn; Creed-Kanashiro, Hilary M; Joseph, Serene A; Gagnon, Anita; Rahme, Elham; Gyorkos, Theresa W

    2013-05-01

    Evidence from randomized controlled trials has shown that delayed cord-clamping is beneficial to infant iron status. The role of maternal anaemia in this relationship, however, has not been established. To determine the effect of maternal anaemia at delivery on the association between timing of umbilical cord-clamping and infant anaemia at 4 and 8 months of age. A cohort of pregnant women admitted to the labour room of Hospital Iquitos (Iquitos, Peru) and their newborns were recruited into the study during two time periods (18 May to 3 June and 6-20 July 2009). Between the two recruitment periods, the hospital's policy changed from early to delayed umbilical cord-clamping. Maternal haemoglobin levels were measured before delivery, and the time between delivery and cord-clamping was recorded at delivery for the entire cohort. Mother-infant pairs were followed-up at 4 (n = 207) and 8 months (n = 184) post partum. Infant haemoglobin levels were measured at follow-up visits. Data were analysed using logistic regression models. The prevalence of maternal anaemia (Hb anaemia was modified by the mother's anaemia status. Significant benefits of delayed cord-clamping in preventing anaemia were found in infants born to anaemic mothers at both 4 months (aOR = 0.59, 95% CI 0.36-0.99) and 8 months (aOR = 0.38, 95% CI 0.19-0.76) of age. The study contributes additional evidence in support of delayed cord-clamping. This intervention is likely to have most public health impact in areas with a high prevalence of anaemia during pregnancy.

  13. Influence of non-steady state during isoglycemic hyperinsulinemic clamp in hypertension. A LIFE substudy

    DEFF Research Database (Denmark)

    Olsen, M H; Andersen, U B; Wachtell, K

    1999-01-01

    We wanted to investigate whether time to steady state was reached within 2 h of insulin infusion during isoglycemic hyperinsulinemic clamp, comparing the glucose uptake index (M/IG) with Bergman's insulin sensitivity index (Sip). We performed a 2-h oral glucose tolerance test and a 3-h isoglycemic....... Because the 2-h M/IG correlated strongly with the 3-h Sip with relatively narrow limits of agreement, it is a good measure of insulin sensitivity. However, a 2-h clamp results in lower insulin sensitivity values in elderly, hypertensive patients due to the fact that steady state is not reached...

  14. Outside-out "sniffer-patch" clamp technique for in situ measures of neurotransmitter release.

    Science.gov (United States)

    Muller-Chrétien, Emilie

    2014-01-01

    The mechanism underlying neurotransmitter release is a critical research domain for the understanding of neuronal network function; however, few techniques are available for the direct detection and measurement of neurotransmitter release. To date, the sniffer-patch clamp technique is mainly used to investigate these mechanisms from individual cultured cells. In this study, we propose to adapt the sniffer-patch clamp technique to in situ detection of neurosecretion. Using outside-out patches from donor cells as specific biosensors plunged in acute cerebral slices, this technique allows for proper detection and quantification of neurotransmitter release at the level of the neuronal network.

  15. Seabed habitat mapping employing single and multi-beam backscatter data: A case study from the western continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Haris, K.; Chakraborty, B.; Ingole, B.S.; Menezes, A.A.A.; Srivastava, R.

    Hz MBES data were acquired using the EM1002 echo-sounding system installed onboard RV “Sagar Sukti” in April 2007. The Simrad EM1002 is a phase interpolated beam-forming MBES with 128 transducer elements forming 111 beams in a semicircular array of 45... cm radius. This echo-sounder was calibrated following a “patch test” to minimize navigational and motion errors as described in the Simrad EM1002 installation manual. The line spacing was around three to four times water depth to provide sufficient...

  16. The electron-impact ionization of Ar and Kr revisited: A critical analysis of double-to-single ionization cross section ratio measurements using the fast-atom-beam technique

    International Nuclear Information System (INIS)

    Tarnovsky, V.; Becker, K.

    1992-01-01

    We report new measurements of the absolute electron-impact double ionization cross sections for Ar and Kr and of the ratios of double-to-single ionization for impact energies from threshold to 200 eV using the crossed electron-beam - fast-atom-beam technique. The work was motivated by the recently highlighted spread of about 30% in the Ar 2+ /Ar + ionization cross section ratios obtained by several groups using different experimental techniques. Such a spread is inconsistent with statistical uncertainties of typically 3% or less that were quoted for the various reported ratios. A similar situation exists for Kr where the spread among the recently published Kr 2+ /Kr + ionization cross section ratios is about 15%. We made an attempt to identify all potential systematic errors inherent to the fast-beam technique that could affect the measurement of cross section ratios with special emphasis on those systematic errors that could influence the detection of singly and doubly charged product ions differently. We found Ar 2+ /Ar + and Kr 2+ /Kr + cross section ratios of, respectively 0.066±0.007 and 0.087±0.008 at 100 eV which confirm earlier measurements using the same experimental technique. The error limits on cross sections ratios of multiple-to-single ionization for the same target atom and at least ±10% for ratios of single ionization cross sections for different target species. Our error limits are dominated by systematic uncertainties of the apparatus which do not cancel when cross section ratios are measured, since the ratios are obtained under similar, but not identical experimental conditions. (orig.)

  17. Modulation of the Pyrococcus abyssi NucS Endonuclease Activity by Replication Clamp at Functional and Structural Levels*

    Science.gov (United States)

    Creze, Christophe; Ligabue, Alessio; Laurent, Sébastien; Lestini, Roxane; Laptenok, Sergey P.; Khun, Joelle; Vos, Marten H.; Czjzek, Mirjam; Myllykallio, Hannu; Flament, Didier

    2012-01-01

    Pyrococcus abyssi NucS is the founding member of a new family of structure-specific DNA endonucleases that interact with the replication clamp proliferating cell nuclear antigen (PCNA). Using a combination of small angle x-ray scattering and surface plasmon resonance analyses, we demonstrate the formation of a stable complex in solution, in which one molecule of the PabNucS homodimer binds to the outside surface of the PabPCNA homotrimer. Using fluorescent labels, PCNA is shown to increase the binding affinity of NucS toward single-strand/double-strand junctions on 5′ and 3′ flaps, as well as to modulate the cleavage specificity on the branched DNA structures. Our results indicate that the presence of a single major contact between the PabNucS and PabPCNA proteins, together with the complex-induced DNA bending, facilitate conformational flexibility required for specific cleavage at the single-strand/double-strand DNA junction. PMID:22431731

  18. Electron beam based transversal profile measurements of intense ion beams; Elektronenstrahl-Diagnostik zur Bestimmung vom transversalen Profil intensiver Ionenstrahlen

    Energy Technology Data Exchange (ETDEWEB)

    El Moussati, Said

    2014-11-03

    application range of the EBI diagnostic method and to benchmark the theoretical model. To achieve this goal a code has been developed in the programming language Python. Different charge distributions were considered and the simulation results have been compared with the theoretical model. The numerical investigations have shown a very good agreement with the theoretical model for deflection angles up to 20 mrad. This value defines the limit for the applicability of the theoretical model. Moreover, the magnetic field of the ion beam has also been taken into acount in the simulations. The results show that at high ion beam currents - starting at about 1 A - the electrons experience a non-negligible displacement along the ion beam axis, which has to be taken into consideration in experiments with intense heavy ion beams. The electrons suffer practically the same displacement under the influence of the magnetic field, regardless of their offset. At an offset of 10 mm the deviation from the shift at the ion beam axis is less than 3 %. For the experimental investigations of the EBI diagnostic method an offline experiment had been set up at the HHT experimental area at GSI in Darmstadt. The Coulomb field of the ion beam had been simulated by electrostatically charged wires. In case of a single wire, the experimental results are in good agreement with the theoretical model for deflection angles up to 20 mrad. This confirms the results of the numerical studies. To simulate the field within an ion beam, several wires have been clamped parallel to each other within a plane perpendicular to the electron beam. The electrons thus could pass through the spaces between the wires. The results of this experiments have quantitatively confirmed the prediction of the theoretical model that the derivative of the deflection angle with respect to the offset is proportional to the charge distribution in the cross section of the ion beam. Quantitatively, however, deviations from the theoretical model

  19. Trans-Z-source and Γ-Z-source neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    Z-source neutral-point-clamped (NPC) inverters are earlier proposed for obtaining voltage buck-boost and three-level switching simultaneously. Their performances are, however, constrained by a trade-off between their input-to-output gain and modulation ratio. This trade-off can lead to high...

  20. Significance of Shrinkage Induced Clamping Pressure in Fiber-Matrix Bonding in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    used in high performance cementitious composite materials.Assuming a Coulomb type of friction on the fiber/matrix interface andusing typical values for the frictional coefficient it is shownthat the shrinkage induced clamping pressure could be one of the mostimportant factors determining the frictional...