WorldWideScience

Sample records for large diameter through-hole

  1. Numerical Analysis of Large Diameter Butterfly Valve

    Science.gov (United States)

    Youngchul, Park; Xueguan, Song

    In this paper, a butterfly valve with the diameter of 1,800 mm was studied. Three-dimensional numerical technique by using commercial code CFX were conducted to observe the flow patterns and to measure flow coefficient, hydrodynamic torque coefficient and so on, when the large butterfly valve operated with various angles and uniform incoming velocity.

  2. New Large Diameter RF Complex Plasma Device

    Science.gov (United States)

    Meyer, John; Nosenko, Volodymyr; Thomas, Hubertus

    2016-10-01

    The Complex Plasma Research Group at the German Aerospace Center (DLR) in Oberpfaffenhofen has built a new large diameter rf plasma setup for dusty plasma experiments. The vacuum chamber is a stainless steel cylinder 0.90 m in diameter and 0.34 m in height with ports for viewing and measurement. A 0.85 m diameter plate in about the center serves as a powered electrode (13.56 MHz) with the chamber walls as the ground. It is pumped on by one of two Oerlikon turbo pumps with a pumping rate of 1100 l/s or 270 l/s. Argon gas is admitted into the chamber by an MKS mass flow meter and pumping is regulated by a butterfly valve to set pressure for experiments. A manual dropper is used to insert dust into the plasma. The dust is illuminated horizontally by a 660 nm 100 mW laser sheet and viewed from above by a Photron FASTCAM 1024 PCI camera. A vertical laser sheet of 635 nm will be used for side imaging. So far, single-layer plasma crystals of up to 15000 particles have been suspended. The particle velocity fluctuation spectra were measured and from these, the particle charge and screening length were calculated. Future experiments will explore the system-size dependence of the plasma crystal properties.

  3. Numerical Simulation of Large Diameter Cylindrical Structure Slamming

    Institute of Scientific and Technical Information of China (English)

    XU Jing; WANG De-yu

    2008-01-01

    The water entry of large diameter cylindrical structure is studied by applying numerical simulation method. The processes of different diameter cylindrical structures impacting water with various constant velocities are calculated numerically. Thereafter, analyzed are the distribution of slamming pressure on structure during slamming course and the influence of slamming velocity and cylindrical diameter on slamming process. Furthermore, presented herein is an equation being used to forecast the peak slamming force on a large diameter cylindrical structure.

  4. Catalytic growth of carbon nanotubes with large inner diameters

    Directory of Open Access Journals (Sweden)

    WEI REN ZHONG

    2005-02-01

    Full Text Available Carbon nanotubes (2.4 g/g catalyst, with large inner diameters were successfully synthesized through pyrolysis of methane on a Ni–Cu–Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of the carbon nanotubes prepared by this method is about 20–60 nm, while their outer diameter is about 40–80 nm. Transmission electron microscopy and X-ray diffraction were employed to investigate the morphology and microstructures of the carbon nanotubes. The analyses showed that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about a slight decrease in the methane conversion and the yield of carbon. The experimental results showed that sodium carbonate is a mildly toxic material which influenced the catalytic activity of the Ni–Cu–Al catalyst and resulted in the formation of carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.

  5. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    of up-to-date facilities has been: Equipment for controlling centrifuge tests, data acquisition, preparation of test samples and equipment for and making of lateral load tests. The present research has been narrowed to investigate the static and cyclic behaviour of stiff piles with a diameter of 1-3 m...... on the structure and the productivity of the turbine. Current design practice for monopiles are based on p-y curves developed for slender piles with a diameter of 0.6 m. The focus on the structure stiffness has entailed a significant research on the soil-structure interaction for large diameter monopiles....... Comparison of the different approaches shows some discrepancy and conflicting statements, but the main findings can be summarized as: • The standard p-y curves are inadequate to describe the behaviour of lateral loaded large diameter rigid piles. • Initial stiffness of the p-y curves is depended...

  6. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    in dry sand by use of centrifuge modelling and to compare the findings with the standard p-y curves. It has been chosen to apply piles with an embedment length of 6 to 10 times the diameter of the applied piles. The general static behaviour of monopiles in dry sand has based on centrifuge tests been...... in sand by use of physical modelling and comparison of the findings with standard p-y curves. The present research is based on use of the centrifuge facilities at Danish Technical University (DTU), the sole geotechnical centrifuge in Scandinavia. It became evident in the initial phase of the research...... that the available centrifuge facilities at DTU was outdated and the focus was changed to establish up-to-date centrifuge facilities for medium to large diameter piles, and to initiate the research on the behaviour of large diameter piles in sand under static and cyclic loading. Key elements in the establishment...

  7. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    . The expected development of offshore wind farms is towards larger farms, larger turbines and larger water depths. Monopiles have been applied widely and it is of interest to investigate the possibilities to further optimize the design and in particular the modelling of the soil-structure interaction...... on the structure and the productivity of the turbine. Current design practice for monopiles are based on p-y curves developed for slender piles with a diameter of 0.6 m. The focus on the structure stiffness has entailed a significant research on the soil-structure interaction for large diameter monopiles...... in dry sand by use of centrifuge modelling and to compare the findings with the standard p-y curves. It has been chosen to apply piles with an embedment length of 6 to 10 times the diameter of the applied piles. The general static behaviour of monopiles in dry sand has based on centrifuge tests been...

  8. Magnetoimpedance of Electroplated Wires with Large Core Diameters

    Institute of Scientific and Technical Information of China (English)

    C. Sirisathitkul; P. Jantaratana

    2009-01-01

    Monolayered Co and trilayered Co/Cu/Co were electroplated on 485 Μm-diameter Cu wires using the bath pH 2.5. These wires can be functioned as magnetic sensors owing to their magnetoimpedance (Ml) effect. By measuring at four different frequencies (100, 250, 500, and 1000 kHz) and Co thicknesses (2.5, 5.0, 10.0, and 25.0Μm), the Ml ratio of electroplated Co on Cu wires tended to increase with increasing Co thickness and frequency of the driving current. The Co/Cu/Co on Cu wires exhibited even higher Ml ratio. The magnetic layer also regulated the magnetic inductions and anisotropy regardless of the size of nonmagnetic core. Nevertheless, the diameter of the Cu core had a significant effect on the Ml ratio. By comparing with the 47.7 μm-diameter Ag cores electroplated by Co and Co/Cu/Co of the same thickness, the Cu cores with a larger diameter gave rise to a larger Ml ratio because their lower electrical resistance enhanced the crossing effect. Substantial Ml ratio was observed even in a low frequency regime because the skin effect occurred at a low frequency in the case of electroplated wires with large core diameters.

  9. A Study of Spiral Tap with Large Diameter

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The design and manufacture of spiral tap yet are in r esearch stage at present. This paper mainly introduces how to calculate its geom etric parameters and scientific selection of them with vector method. In additio n, an empiric formula of the tool life of spiral tap with large diameter is esta blished by method of correlation. The practice of design, manufacture and applying proves the advantage of spiral tap by the comparison between the spiral tap and common tap with same size. In the application of...

  10. Note: Computer controlled rotation mount for large diameter optics

    CERN Document Server

    Rakonjac, Ana; Deb, Amita B; Kjærgaard, Niels

    2012-01-01

    We describe the construction of a motorized optical rotation mount with a 40 mm clear aperture. The device is used to remotely control the power of large diameter laser beams for a magneto-optical trap (MOT). A piezo-electric ultrasonic motor on a printed circuit board (PCB) provides rotation with a precision better than 0.03 deg and allows for a very compact design. The rotation unit is controlled from a computer via serial communication, making integration into most software control platforms straightforward.

  11. Molecular transport through large-diameter DNA nanopores

    Science.gov (United States)

    Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G.; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R.; Dietz, Hendrik; Simmel, Friedrich C.

    2016-01-01

    DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ≈4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ≈3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration. PMID:27658960

  12. Molecular transport through large-diameter DNA nanopores

    Science.gov (United States)

    Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G.; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R.; Dietz, Hendrik; Simmel, Friedrich C.

    2016-09-01

    DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ~4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ~3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration.

  13. Solar furnace satellite for large diameter crystal growth in space

    Science.gov (United States)

    Overfelt, Tony; Wells, Mark; Blake, John

    1993-02-01

    Investigators worldwide are preparing experiments to test the influence of low gravity found in space on the growth of many crystalline materials. However, power limitations prevent existing space crystal growth furnaces from being able to process samples any larger than about 2 cm, and in addition, the background microgravity levels found on the Space Shuttle are not low enough to significantly benefit samples much larger than 2 cm. This paper describes a novel concept of a free-flying platform utilizing well-established solar furnace technology to enable materials processing in space experiments on large-diameter crystals. The conceptual design of this Solar Furnace Satellite is described along with its operational scenario and the anticipated g levels.

  14. Experiments with large diameter gravity driven impacting liquid jets

    Science.gov (United States)

    Storr, G. J.; Behnia, M.

    The phenomenon of a liquid jet released under gravity and falling through or impacting onto another liquid before colliding with an obstructing solid surface has been studied experimentally under isothermal conditions. Usually the jet diameter was sufficiently large to ensure jet coherency until collision. Direct flow visualization was used to study jets released into water pools with no air head space and jets impacting onto water pools after falling through an air head space. It is shown that distances predicting the onset of buoyancy and the entrainment of air using derivations from continuous plunging jets, are not applicable for impacting jets. The morphology of jet debris after collision with the solid surfaces correlates with the wetting properties of the jet liquid on the surface.

  15. Sustainable yields from large diameter wells in shallow weathered aquifers

    Science.gov (United States)

    Rushton, K. R.; de Silva, C. S.

    2016-08-01

    Large diameter wells in shallow weathered aquifers provide a valuable source of water for domestic and agricultural purposes in many locations including the Indian subcontinent. However, when used for irrigation, these wells often fail towards the end of the dry season. By considering two case studies in the dry and intermediate rainfall zones of Sri Lanka, reasons for the limited yield of these wells are identified. The first case study is concerned with a sloping catchment; a significant proportion of the precipitation during the rainy season either becomes runoff or passes down-gradient through the aquifer and is discharged at the ground surface. Furthermore, during the dry season, groundwater discharge continues. In the second case study the topography is generally flat but, even though the aquifer fills most years during the rainy season, there is often only sufficient water to irrigate about half of each farmer's holding. These investigations are based on field information and the development of conceptual and computational models. Of critical importance in assessing the long term yield of a well is the formation of a seepage face on the side of the well, with the water table a significant distance above the pumping water level. Consequently the water table may only be lowered to about half the depth of the well. The paper concludes with recommendations for the exploitation of groundwater from shallow weathered aquifers to minimise the risk of failure during the dry season.

  16. FACES WITH LARGE DIAMETER ON THE SYMMETRICAL TRAVELING SALESMAN POLYTOPE

    NARCIS (Netherlands)

    SIERKSMA, G; TIJSSEN, GA

    1992-01-01

    This paper deals with the symmetric traveling salesman polytope and contains three main theorems. The first one gives a new characterization of (non)adjacency. Based on this characterization a new upper bound for the diameter of the symmetric traveling salesman polytope (conjectured to be 2 by M. Gr

  17. 78 FR 60897 - Certain Welded Large Diameter Line Pipe From Japan

    Science.gov (United States)

    2013-10-02

    ... COMMISSION Certain Welded Large Diameter Line Pipe From Japan Determination On the basis of the record \\1... the antidumping duty order on certain welded large diameter line pipe from Japan would likely to lead... Certain Welded Large Diameter Line Pipe from Japan: Investigation No. 731-TA-919 (Second Review). By order...

  18. Experimental study on stability of sunken large diameter cylindrical structure on sandy seabed during construction period

    Institute of Scientific and Technical Information of China (English)

    秦崇仁; 庞红犁; 李世森; 张伟

    2002-01-01

    A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger diameter cylindrical structure, a set of values is derived also for the critical stability indices of the large diameter cylinder sunken to the sandy seabed.

  19. Dynamic Soil-Pile Interaction for large diameter monopile foundations

    DEFF Research Database (Denmark)

    Zania, Varvara

    2013-01-01

    fatigue may be problematic. In the third case except from the cost increase, the wind induced fatigue is an additional issue to be dealt with. The second concept is the one prevailing in current design practice and it actually sets the natural frequency of vibration of the OWT inside the narrow margin......Monopile foundations have been used in a large extent to support offshore wind turbines (OWT), being considered as a reliable and cost effective design solution. The accurate estimation of their dynamic response characteristics is essential, since the design of support structures for OWTs has been......’ rule and are usually reported in double terms of the stiffness of the OWT and the foundation, i.e. soft –soft, soft – stiff, and stiff – stiff design approaches. In the first case the eigenfrequency of the system is reduced to excessively low values, where the cost reduction is considerable but wave...

  20. Reliability Analysis of Bearing Capacity of Large-Diameter Piles under Osterberg Test

    Directory of Open Access Journals (Sweden)

    Lei Nie

    2013-05-01

    Full Text Available This study gives the reliability analysis of bearing capacity of large-diameter piles under osterberg test. The limit state equation of dimensionless random variables is utilized in the reliability analysis of vertical bearing capacity of large-diameter piles based on Osterberg loading tests. And the reliability index and the resistance partial coefficient under the current specifications are calculated using calibration method. The results show: the reliable index of large-diameter piles is correlated with the load effect ratio and is smaller than the ordinary piles; resistance partial coefficient of 1.53 is proper in design of large-diameter piles.

  1. Selective control of small versus large diameter axons using infrared laser light (Conference Presentation)

    Science.gov (United States)

    Lothet, Emilie H.; Shaw, Kendrick M.; Horn, Charles C.; Lu, Hui; Wang, Yves T.; Jansen, E. Duco; Chiel, Hillel J.; Jenkins, Michael W.

    2016-03-01

    Sensory information is conveyed to the central nervous system via small diameter unmyelinated fibers. In general, smaller diameter axons have slower conduction velocities. Selective control of such fibers could create new clinical treatments for chronic pain, nausea in response to chemo-therapeutic agents, or hypertension. Electrical stimulation can control axonal activity, but induced axonal current is proportional to cross-sectional area, so that large diameter fibers are affected first. Physiologically, however, synaptic inputs generally affect small diameter fibers before large diameter fibers (the size principle). A more physiological modality that first affected small diameter fibers could have fewer side effects (e.g., not recruiting motor axons). A novel mathematical analysis of the cable equation demonstrates that the minimum length along the axon for inducing block scales with the square root of axon diameter. This implies that the minimum length along an axon for inhibition will scale as the square root of axon diameter, so that lower radiant exposures of infrared light will selectively affect small diameter, slower conducting fibers before those of large diameter. This prediction was tested in identified neurons from the marine mollusk Aplysia californica. Radiant exposure to block a neuron with a slower conduction velocity (B43) was consistently lower than that needed to block a faster conduction velocity neuron (B3). Furthermore, in the vagus nerve of the musk shrew, lower radiant exposure blocked slow conducting fibers before blocking faster conducting fibers. Infrared light can selectively control smaller diameter fibers, suggesting many novel clinical treatments.

  2. Risk of dislocation using large- vs. small-diameter femoral heads in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Plate Johannes F

    2012-10-01

    Full Text Available Abstract Background Dislocation remains a difficult problem in total hip arthroplasty. Large-diameter femoral heads may lower the incidence of dislocation by enhancing the jump distance and decreasing impingement, but their performance against small-diameter heads has not been assessed. This study compared the mid-term radiographic and functional outcomes of two matched cohorts of patients undergoing total hip arthroplasty who had a high pre-operative risk for dislocation and who received either small-diameter (26- or 28-millimeters or large-diameter (≥36-millimeters femoral heads. Methods All patients who received large-diameter heads (≥36-millimeter between 2002 and 2005, and who had pre-operative risk factors for dislocation, were identified in the institution’s joint registry. Forty-one patients (52 hips who received large-diameter heads were identified, and these patients were matched to 48 patients (52 hips in the registry who received small-diameter femoral heads. Results At mean final follow-up of 62 months (range, 49 to 101 months, both groups achieved excellent functional outcomes as measured by Harris Hip scores, with slightly better final scores in the large-diameter group (90 vs. 83 points. No patient showed any radiographic signs of loosening. No patient dislocated in the large-diameter femoral head group; the smaller-diameter group had a greater rate of dislocation (3.8%, 2 out of 52. Conclusions Large-diameter femoral head articulations may reduce dislocation rates in patients who have a high pre-operative risk for dislocation while providing the same functional improvements and safety as small-diameter bearings.

  3. Experimental study on large diameter drilling in hard rock annular coring

    Institute of Scientific and Technical Information of China (English)

    Yinzhu WU; Guochun YANG; Wenchen WANG

    2008-01-01

    Based on analyzing method of large diameter hard rock drilling at home and abroad, the authors proposed a set of drilling of large diameter hard rock annular coring in low energy consumption, low cost and high efficiency. The prototype of drilling tools was designed and was made. The experimental result of the prototype indicates that this plan and technology are feasible and reach the anticipated object of design. A set of drilling tools has been offered for the constructs of large diameter hard rock coring.

  4. Experimental Research on Large Diameter Cast-in-Place Piles Embedded in Rock

    Institute of Scientific and Technical Information of China (English)

    衡朝阳; 何满潮; 姚爱军

    2001-01-01

    This paper expatiated the field test of large diameter cast-in-place piles embedded in soft rock, including static loading test, high or low strain dynamic test, measurement of stresses and strains of pile body, and pressure measurements between pile tip and soft rock. The relative in-situ test problems are discussed. Based on the limit equilibrium theory and the load transfer equation, a synthesis method of analyzing the ultimate carrying capacity of single large diameter pile is put forward. The research results show that the key to determining the ultimate carrying capacity of single pile with a large diameter is the analysis of the intensity of soft rock.

  5. An Approach to Stability Analysis of Embedded Large-Diameter Cylinder Quay

    Institute of Scientific and Technical Information of China (English)

    王元战; 祝振宇

    2002-01-01

    The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundationbed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and off-shore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis ofthe embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, em-bedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile walltype. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and amethod for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of sig-nificant parameters on the stability of the large-dianeter cylinder quay of the cylinder pile wall type is investigated throughnumerical calculation.

  6. Development of nondestructive testing techniques for plated-through holes in multilayer printed circuit boards

    Science.gov (United States)

    Anthony, P. L.; Mcmurtrey, J. E.

    1971-01-01

    The development of a nondestructive test with the capability to interrogate plated-through holes as small as 0.51 millimeters inside diameter is discussed. The system can detect defects such as holes, voids, cracks, and thin spots that reduce the current carrying capability of plates-through interconnects by 20 percent or more. Efforts were directed toward the design and fabrication of magnetic circuitry mutual coupling probes and to evaluate the effectiveness of these devices for detecting in multilayer board plated-through holes.

  7. Large-diameter femoral heads in total hip arthroplasty: an evidence-based review.

    Science.gov (United States)

    Banerjee, Samik; Pivec, Robert; Issa, Kimona; Kapadia, Bhaveen H; Khanuja, Harpal S; Mont, Michael A

    2014-11-01

    Recent advances in the wear characteristics and material properties of highly cross-linked polyethyl-ene and fourth-generation ceramic bearings have led to increasing use of large-diameter (≥ 36 mm) femoral heads in total hip arthroplasty (THA). In this article, we review the current concepts and principles behind use of large-diameter ceramic or cobalt-chromium femoral heads on polyethylene bearings in THA. We specifically review the biomechanics, some of the early concerns about polyethylene wear and rim fractures, recent improvements in material properties of polyethylene and ceramic bearings, dislocation rates, and clinical and functional outcomes of large-diameter heads in THA. Recent literature suggests that the incidence of dislocation has been substantially reduced because of improvements in jump distance and impingement-free range of motion with use of large-diameter heads. Limited evidence suggests excellent short-term and midterm clinical and functional outcomes with these heads.

  8. СOMPACT COMPLEX FOR PROCESSING OF LARGE-DIAMETER PIPES INTO THE ROLLING STEEL PRODUCTS

    OpenAIRE

    Steblov, A. В.; A. A. Zlobin

    2016-01-01

    A mini-plant conception for processing of previously used large-diameter pipes into the small-section rolling steel products. Projects with capacity from 15 to 200 thousand tons per year are realized in the UIS.

  9. Estimates of Radiation Dose Rates Near Large Diameter Sludge Containers in T Plant

    CERN Document Server

    Himes, D A

    2002-01-01

    Dose rates in T Plant canyon during the handling and storage of large diameter storage containers of K Basin sludge were estimated. A number of different geometries were considered from which most operational situations of interest can be constructed.

  10. Annular Pulse Shaping Technique for Large-Diameter Kolsky Bar Experiments on Concrete

    Science.gov (United States)

    2014-10-01

    lt ag e (V ) Time (microsecond) Fig. 5 Linear incident wave generated using an annular copper pulse shaper (O.D. = 25.4 mm, I.D. = 14.4 mm). Note that...AFRL-RW-EG-TP-2014-005 Annular Pulse Shaping Technique for Large- Diameter Kolsky Bar Experiments on Concrete...NUMBER (Include area code) 13-6-2014 Technical Publication October 2012 - February 2014 ANNULAR PULSE SHAPING TECHNIQUE FOR LARGE-DIAMETER KOLSKY BAR

  11. Maximum length of large diameter Czochralski silicon single crystals at fracture stress limit of seed

    Science.gov (United States)

    Kim, K. M.; Smetana, P.

    1990-03-01

    Growth of large diameter Czochralski (CZ) silicon crystals require complete elimination of dislocations by means of Dash technique, where the seed diameter is reduced to a small size typically 3 mm in conjunction with increase in the pull rate. The maximum length of the large CZ silicon is estimated at the fracture stress limit of the seed neck diameter ( d). The maximum lengths for 200 and 300 mm CZ crystals amount to 197 and 87 cm, respectively, with d = 0.3 cm; the estimated maximum weight is 144 kg.

  12. Ecological importance of large-diameter trees in a temperate mixed-conifer forest.

    Science.gov (United States)

    Lutz, James A; Larson, Andrew J; Swanson, Mark E; Freund, James A

    2012-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m(2). We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees.

  13. Evaluation of the Load-Displacement Relationships for Large-Diameter Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Brodbaek, K. T.; Moller, M.;

    2009-01-01

    was developed for slender piles with diameters much less than 6 m and it is based on a limited number of tests. The aim of the present work is to extend the p-y curve method to large-diameter non-slender piles by considering the effects of the pile diameter on the soil response. The main focus is the initial...... stiffness of the p-y curves. The evaluation is based on experimental work as well as three-dimensional numerical analyses in the commercial programme FLAC3D....

  14. Centrifuge modelling of large diameter pile in sand subject to lateral loading

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    Large-diameter (4 to 6 m) rigid monopiles are often used as foundations for offshore wind turbines. The monopiles are subjected to large horizontal forces and overturning moments and they are traditionally designed based on the p-y curve method. The p-y curves recommended in offshore design...... and cyclic behaviour of large diameter rigid piles in dry sand by use of physical modelling. The physical modelling has been carried out at Department of Civil Engineering at the Danish Technical University (DTU.BYG), in the period from 2005 to 2009. The main centrifuge facilities, and especially...... the equipment for lateral load tests were at the start of the research in 2005 outdated and a major part of the work with the geotechnical centrifuge included renovation and upgrading of the facilities. The research with respect to testing of large diameter piles included:  Construction of equipment...

  15. Numerical Modelling of Large-Diameter Steel Piles at Horns Rev

    DEFF Research Database (Denmark)

    Augustesen, Anders Hust; Brødbæk, K. T.; Møller, M.;

    2009-01-01

    Today large-diameter monopiles are the most common foundation type used for large offshore wind farms. This paper aims to investigate the behaviour of monopiles under monotonic loading taking the interaction between the pile and the subsoil into account. Focus is paid to a monopile used as founda......Today large-diameter monopiles are the most common foundation type used for large offshore wind farms. This paper aims to investigate the behaviour of monopiles under monotonic loading taking the interaction between the pile and the subsoil into account. Focus is paid to a monopile used...... as foundation for a wind turbine at Horns Rev located in the Danish sector of the North Sea. The outer diameter of the pile is 4 m and the subsoil at the location consists primarily of sand. The behaviour of the pile is investigated under realistic loading conditions by means of a traditional Winkler...

  16. The importance of large-diameter trees to forest structural heterogeneity.

    Directory of Open Access Journals (Sweden)

    James A Lutz

    Full Text Available Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥ 1 cm dbh, all 1,966 snags ≥ 10 cm dbh, and all shrub patches ≥ 2 m(2. Basal area of the 26 woody species was 62.18 m(2/ha, of which 61.60 m(2/ha was trees and 0.58 m(2/ha was tall shrubs. Large-diameter trees (≥ 100 cm dbh comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR up to 9 m (P ≤ 0.001. Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla, or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata. Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.

  17. The importance of large-diameter trees to forest structural heterogeneity.

    Science.gov (United States)

    Lutz, James A; Larson, Andrew J; Freund, James A; Swanson, Mark E; Bible, Kenneth J

    2013-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥ 1 cm dbh, all 1,966 snags ≥ 10 cm dbh, and all shrub patches ≥ 2 m(2). Basal area of the 26 woody species was 62.18 m(2)/ha, of which 61.60 m(2)/ha was trees and 0.58 m(2)/ha was tall shrubs. Large-diameter trees (≥ 100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P ≤ 0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.

  18. The vertical shaft construction technology of cutter head transformation of large diameter shield

    Institute of Scientific and Technical Information of China (English)

    He Feng; Wang Ying; Wang Zhenfei; Wang Baiquan

    2012-01-01

    Taking vertical shaft construction of cutter transformation of the Beijing underground diameter shield for ex- ample, the design and construction of cutter structure transformation under complex boundary conditions for large diameter shield were discussed. Practice about how to ensure the structure safety of the shaft as well as well-coordinated shield construction was explored, and reliable solutions were provided successfully, which can provide reference for similar projects.

  19. Stability analysis of large diameter thin-walled tube beam-columns

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on a blind spot in the current design standard of steel structures,the large diameter thin-walled tube beam-columns are analyzed using nonlinear finite element method in this paper.The influence of several factors on stability capacity of the large diameter thinwalled tube beam-columns is taken into account.Thus,according to the correlative design standard of steel structures,and on the basis of the numerical analytical results by the finite element methods,the calculation formulas of the stability bearing capacity are presented for beam-column members of the large diameter thin-walled tubes.Three tests of thin-walled steel tube beam-columns were reported.Test results for deformations and ultimate strength are found to be in a good agreement with the corresponding values predicted by the calculation formulas,and the proposed methods can be used in design practice.

  20. The effect of manufacturing tolerances on the load carrying capacity of large diameter bearings

    Indian Academy of Sciences (India)

    Starvin M S; Manisekar K

    2015-09-01

    This paper deals with simplified 3D finite element (FE) analysis on the effect of manufacturing tolerances on the load carrying capacity of large diameter bearings based on Hertz theory. The nonlinear connector elements are used to model the rolling elements. This model enables us to evaluate the contact load on the rolling elements with relatively reduced calculation time. FE study has been carried out by allocating tolerance on balls and raceways using Monte Carlo simulation technique. The variation in dimension on balls is taken as per IS 2898-1976. A coding has been developed and employed for Monte Carlo simulation. Using the results of Monte Carlo simulation, tolerance has been assigned to the elements of large diameter bearing. From the results of finite element analysis, it is identified that analysis of large diameter bearing with tolerance on ball and raceway will lead to safe design.

  1. Stress Wave Dispersion in Large-Diameter SHPB and Its Manifold Manifestations

    Institute of Scientific and Technical Information of China (English)

    王永刚; 王礼立

    2004-01-01

    The wave dispersion due to the lateral inertia in the split Hopkinson pressure bar(SHPB) with large-diameter bar is numerically analyzed by means of the LS-DYNA3D code. The results show that, ① the stress distribution across the bar section is non-uniform along the radius direction and such non-uniformity depends on the material Poisson ratio and propagation distance; ② with increasing the bar diameter, the high frequency oscillations are notably enhanced and the rise time of wave front becomes longer, meanwhile the amplitude of the stress wave attenuates; ③ with decreasing the rise time of wave front, the wave dispersion markedly enhanced, particularly in the large diameter bar. All of those effects should not be neglected in order to obtain accurate results by the SHPB test.

  2. СOMPACT COMPLEX FOR PROCESSING OF LARGE-DIAMETER PIPES INTO THE ROLLING STEEL PRODUCTS

    Directory of Open Access Journals (Sweden)

    A. В. Steblov

    2016-01-01

    Full Text Available A mini-plant conception for processing of previously used large-diameter pipes into the small-section rolling steel products. Projects with capacity from 15 to 200 thousand tons per year are realized in the UIS.

  3. Magnetomotive forming for precision sizing and joining of large-diameter tubes

    Science.gov (United States)

    Bennight, J. D.; Schwinghamer, R. J.

    1969-01-01

    Portable electromagnetic coil enables high precision expansion or constriction and joining of large diameter metal tubes. A nonconducting mandrel or forming die is used on the side of the tubes wall opposite the coil. The coil is insulated from the tube by a thin plastic sleeve.

  4. Physical Modelling of Large Diameter Piles in Coarse-Grained Soil

    DEFF Research Database (Denmark)

    Brødbæk, K. T.; Augustesen, Anders Hust; Møller, M.

    2011-01-01

    modelling (large- or small-scale). This paper investigates the effects of diameter on the initial part of the p-y curves by small-scale testing. A new and innovative test setup is presented. In order to minimize scale effects the tests are successfully carried out in a pressure tank enabling the possibility...

  5. Effects of Diameter on Initial Stiffness of P-Y Curves for Large-Diameter Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Augustesen, Anders Hust

    2010-01-01

    For offshore wind turbines, monopile foundations with diameters of 4–6m are often employed. The Winkler model approach, where the soil resistance is modelled as uncoupled springs with spring stiffness’ given by p-y curves, is traditionally employed for the design of monopiles. However, this metho...... analyses by means of the commercial program FLAC3D incorporating a Mohr-Coulomb failure criterion. The numerical model is validated with laboratory tests in a pressure tank at Aalborg University....

  6. Material characteristics of CLEARCERAM-Z HS for use in large diameter mirror blanks

    Science.gov (United States)

    Kishi, Takayuki; Goto, Naoyuki; Hoffman, Brion; Kawashima, Yasuyuki; Suzuki, Kenji; Yoshizawa, Kazuharu; Suzuki, Kaito

    2010-07-01

    There is growing interest within the Astronomical community in the development and use of very large aperture telescopes which will incorporate the latest advancements in optical materials. Two of the most notable of these large size telescope projects, the Thirty Meter Telescope (TMT) and European Extremely Large Telescope (E-ELT), will use mirror segments in the actively controlled primary mirrors. In this paper we present the results of a material characteristics study on Ohara CLEARCERAM®-Z HS large diameter blanks which includes data on the CTE, CTE uniformity, residual stress and internal quality targeting potential use in the TMT Primary Mirror Segment Banks.

  7. Experimental Validation and Design Review of Wave Loads on Large-Diameter Monopiles

    OpenAIRE

    Frimann-Dahl, Joakim Fürst

    2015-01-01

    The objective of the thesis work was to explore challenges related to ULS wave loading on offshore wind turbines, with special emphasis on large-diameter inertia-dominated monopile foundations. Experimental studies testing ULS loads on a 6.9-m diameter pile in eight different three-hour sea states were performed in two water depths. The wave conditions were set to represent those at location 2 of Creyke Beck B at Dogger Bank, with specified sea state return periods up to 1000 years. The t...

  8. PHOS Experiment: Thermal Response of a Large Diameter Pulsating Heat Pipe on Board REXUS-18 Rocket

    Science.gov (United States)

    Creatini, F.; Guidi, G. M.; Belfi, F.; Cicero, G.; Fioriti, D.; Di Prizio, D.; Piacquadio, S.; Becatti, G.; Orlandini, G.; Frigerio, A.; Fontanesi, S.; Nannipieri, P.; Rognini, M.; Morganti, N.; Filippeschi, S.; Di Marco, P.; Fanucci, L.; Baronti, F.; Mameli, M.; Marengo, M.; Manzoni, M.

    2015-09-01

    In the present work, the results of two Closed Loop Pulsating Heat Pipes (CLPHPs) tested on board REXUS-1 8 sounding rocket in order to get experimental data over a relatively broad reduced gravity period (about 90 s) are thoroughly discussed. The CLPHPs are partially filled with refrigerant FC-72 and have, respectively, an inner tube diameter larger (3 .0 mm) and slightly smaller (1 .6 mm) than a critical diameter defined on Earth gravity conditions. On ground, the small diameter CLPHP works as a real Pulsating Heat Pipe (PHP): the typical capillary slug flow pattern forms inside the device and the heat exchange is triggered by self-sustained thermally driven oscillations of the working fluid. Conversely, the large diameter CLPHP behaves like a two-phase thermosyphon in vertical position while does not operate in horizontal position as the working fluid stratifies within the tube and surface tension is not able to balance buoyancy. Then, the idea to test the CLPHPs under reduced gravity conditions: as soon as gravity reduces, buoyancy becomes less intense and the typical capillary slug flow pattern can also forms within a tube with a larger diameter. Moreover, this allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience the expected reduced gravity conditions due to a failure of the yo-yo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described.

  9. A suspended core nanofiber with unprecedented large diameter ratio of holey region to core.

    Science.gov (United States)

    Liao, Meisong; Chaudhari, Chitrarekha; Yan, Xin; Qin, Guanshi; Kito, Chihiro; Suzuki, Takenobu; Ohishi, Yasutake

    2010-04-26

    For a suspended core nanofiber, the holey region is expected to be as large as possible to propagate the light at wavelengths as long as possible. Additionally, a large holey region is significant for its applications in sensors. However, the fabrication of nanofiber with large holey region is still a challenge so far. In this paper a method, which involves pumping positive pressure of nitrogen gas in both the cane fabrication and fiber-drawing processes, was proposed. A suspended core nanofiber, with a core diameter of around 480 nm and an unprecedented diameter ratio of holey region to core (DRHC) of at least 62, was fabricated in the length of several hundred meters. Owing to the large holey region, the confinement loss of the suspended core nanofiber is insignificant when the wavelength of light propagated in it is 1700 nm. For this fabrication technique, the nanowire length, fabrication efficiency, and the uniformity in the diameter are much superior to those of the nanowires fabricated in other ways. Finally, single mode third harmonic generation was observed by this nanofiber under the pump of a 1557 nm femtosecond fiber laser. This work shows the prospect of fabrication of nanostructured waveguide in glass materials by an inflation technique.

  10. Observing the Moon at Microwave Frequencies Using a Large-Diameter Deep Space Network Antenna

    Science.gov (United States)

    Morabito, David D.; Imbriale, William; Keihm, Stephen

    2008-03-01

    The Moon radiates energy at infrared and microwave wavelengths, in addition to reflecting sunlight at optical wavelengths. As a result, an antenna pointed at or near the Moon will result in an increase in system operating noise temperature, which needs to be accounted for in RF telecommunications, radio science or radiometric link calculations. The NASA Deep Space Network (DSN) may use its large-diameter antennas in future lunar robotic or human missions, and thus it is important to understand the nature of this temperature incre ase as a function of observing frequency, lunar phase, and angular position of the antenna beam on the lunar disk. This paper reports on a comprehensive lunar noise temperature measurement campaign and associated theoretical treatment for a 34-m diameter Deep Space Network antenna observing an extended source such as the Moon. A set of measurements over a wide range of lunar phase angles was acquired at DSS-13, a 34-m diameter beam waveguide antenna (BWG) located at Goldstone, California at 2.3 GHz (S-band), 8.4 GHz (X-band) and 32 GHz (Ka-band). For validation purposes, independent predictions of noise temperature increase were derived using a physical optics characterization of the 34-m diameter antenna gain patterns and Apollo model-based brightness temperature maps of the Moon as input. The model-based predictions of noise temperature increase were compared with the measurements at all three frequencies. In addition, a methodology is presented that relates noise temperature increase due to the Moon to disk-centered or disk-averaged brightness temperature of the Moon at the microwave frequencies of interest. Comparisons were made between the measurements and models in the domain of lunar disk-centered and disk-averaged brightness temperatures. It is anticipated that the measurements and associated theoretical development will be useful in developing telecommunications strategies for future high-rate Ka-band communications where large

  11. The Measurement and Control of Diameter in Large-Scale Part Processing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on laser-scanned measuring technology, a met ho d of on-line dynamic non-contact measurement and feedback control of processin g dimension, i.e. the double edges laser-scanned large diameter on-line dynami c measurement and control system is presented, which can be used to measure diam eter in large-scale machine part processing. In this paper, the working princip le, overall structure and microcomputer real-time control and data processing s ystem of the system are discussed in detail, the method of ...

  12. Soil-Structure Interaction for Non-Slender, Large-Diameter Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal

    . The monopile foundation concept has been employed as the foundation for the majority of the currently installed offshore wind turbines. Therefore, this PhD thesis concerns the soil-pile interaction for non-slender, large-diameter offshore piles. A combination of numerical and physical modelling has been....... Hence, the application of an overburden pressure is possible. The timescale of the backfill process and the compaction of soil material backfilled around piles in storm conditions have been investigated by means of large-scale physical modelling....

  13. The large adaptive reflector: a 200-m diameter wideband centimeter- to meter-wave radio telescope

    Science.gov (United States)

    Carlson, Brent; Bauwens, Luc; Belostotski, Leonid; Cannon, Elizabeth; Chang, Ya-Ying; Deng, Xiaohui; Dewdney, Peter E.; Fitzsimmons, Joeleff T.; Halliday, David; Kuerschner, Kai; Lachapelle, Gerard; Lo, David; Mousavi, Pedram; Nahon, Meyer; Shafai, Lot; Stiemer, Sigfried F.; Taylor, Russell; Veidt, Bruce

    2000-07-01

    The Large Adaptive Reflector (LAR) is a concept for a low- cost, large aperture, wideband, radio telescope, designed to operate over the wavelength range from 2 m to 1.4 cm. It consists of a 200-m diameter actuated-surface parabolic reflector with a focal length of 500 m, mounted flat on the ground. The feed is held in place by a tension-structure, consisting of three or more tethers tensioned by the lift of a large, helium-filled aerostat -- a stiff structure that effectively resists wind forces. The telescope is steered by simultaneously changing the lengths of the tethers with winches (thus the position of the feed) and by modifying the shape of the reflector. At all times the reflector configuration is that of an offset parabolic antenna, with the capability to point anywhere in the sky above approximately 15 degree Elevation Angle. At mid-range wavelengths, the feed is a multi-beam prime-focus phased array, about 5 m diameter; at meter wavelengths, it is a single-beam phased array of up to 10 m diameter. Simulations have shown that in operating wind conditions (10 m/s average speed with 2.5 m/s gusts), the position of the feed platform can be stabilized to within a few cm over time scales of approximately 20 s. Research indicates that the telescope concept is feasible and that an order of magnitude improvement in cost per m2 of collecting area over traditional designs of large parabolic antennas can be achieved.

  14. Vertical vibration of a large diameter pipe pile considering transverse inertia effect of pile

    Institute of Scientific and Technical Information of China (English)

    郑长杰; 刘汉龙; 丁选明; 周航

    2016-01-01

    Considering the transverse inertia effect of pile, the vertical dynamic response of a large diameter pipe pile in viscoelastic soil layer is studied. The wave propagations in the outer and inner soil are simulated by three-dimensional elastodynamic theory and those in the pile are simulated by Rayleigh-Love rod theory. The vertical and radial displacements of the outer and inner soil are obtained by utilizing Laplace transform technique and differentiation on the governing equations of soils. Then, based on the continuous conditions between the pile and soils, the displacements of the pile are derived. The frequency domain velocity admittance and time domain velocity response of the pile top are also presented. The solution is compared to a classical rod model solution to verify the validity. The influences of the radii and Poisson ratio of pile on the transverse inertia effect of pile are analyzed. The parametric study shows that Poisson ratio and outer radius of pile have significant influence on the transverse inertia effect of large diameter pipe piles, while the inner radius has little effect.

  15. Testing of Large Diameter Fresnel Optics for Space Based Observations of Extensive Air Showers

    Science.gov (United States)

    Adams, James H.; Christl, Mark J.; Young, Roy M.

    2011-01-01

    The JEM-EUSO mission will detect extensive air showers produced by extreme energy cosmic rays. It operates from the ISS looking down on Earth's night time atmosphere to detect the nitrogen fluorescence and Cherenkov produce by the charged particles in the EAS. The JEM-EUSO science objectives require a large field of view, sensitivity to energies below 50 EeV, and must fit within available ISS resources. The JEM-EUSO optic module uses three large diameter, thin plastic lenses with Fresnel surfaces to meet the instrument requirements. A bread-board model of the optic has been manufactured and has undergone preliminary tests. We report the results of optical performance tests and evaluate the present capability to manufacture these optical elements.

  16. LARGE EDDY SIMULATION COMBINED WITH EQUIVALENT DIAMETER FOR TURBULENT JET MODELLING AND GAS DISPERSION

    Directory of Open Access Journals (Sweden)

    E. S. Ferreira Jr.

    Full Text Available Abstract CFD modelling combines transport phenomena and numerical approaches to solve physical problems. Although numerical modelling of flow scenarios is the cutting edge of flow modelling, there seems to be room for improvement. This paper proposes an approach for jet modelling in a low Mach number computational code. The methodology is based on the equivalent diameter and velocity profile calculated downstream from the jet leak orifice. The novel model DESQr (Diameter of Equivalent Simulation for Quicker Run is combined with LES (Large Eddy Simulation to calculate the gas jet profile due to accidental releases. The model is implemented in the framework of FDS (Fire Dynamics Simulator and the open source code is modified to handle gas dispersion scenarios. Numerical findings for jet modelling and gas dispersion are compared with experimental data. The results are also compared with a commercial CFD tool. Good agreement is observed. Significant computational time reduction is achieved. A free open source CFD tool emerges and the results presented in this work are promising.

  17. Large-diameter burrows of the Triassic Ischigualasto Basin, NW Argentina: paleoecological and paleoenvironmental implications.

    Directory of Open Access Journals (Sweden)

    Carina E Colombi

    Full Text Available Large-diameter ichnofossils comprising three morphotypes have been identified in the Upper Triassic Ischigualasto and Los Colorados formations of northwestern Argentina. These burrows add to the global record of the early appearance of fossorial behavior during early Mesozoic time. Morphotypes 1 and 2 are characterized by a network of tunnels and shafts that can be assigned to tetrapod burrows given similarities with previously described forms. However, differences in diameter, overall morphology, and stratigraphic occurrence allow their independent classification. Morphotype 3 forms a complex network of straight branches that intersect at oblique angles. Their calcareous composition and surface morphology indicate these structures have a composite biogenic origin likely developed due to combined plant/animal interactions. The association of Morphotypes 1 and 2 with fluvial overbank lithologies deposited under an extremely seasonal arid climate confirms interpretations that the early appearance of burrowing behavior was employed by vertebrates in response to both temperature and moisture-stress associated with seasonally or perpetually dry Pangean paleoclimates. Comparisons of burrow morphology and biomechanical attributes of the abundant paleovertebrate fauna preserved in both formations permit interpretations regarding the possible burrow architects for Morphotypes 1 and 2. In the case of the Morphotype 1, the burrow constructor could be one of the small carnivorous cynodonts, Ecteninion or Probelesodon. Assigning an architect for Morphotype 2 is more problematic due to mismatches between the observed burrow morphology and the size of the known Los Colorados vertebrates.

  18. Explosive charge for the explosive welding of large diameter pipes, and a method for its manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, H.; Sjoeberg, P.; Leif, Svensson

    1989-06-13

    This invention relates to an explosive charge intended for the explosive jointing of primarily large-diameter pipes, such as pipeline pipes. The charge according to the invention is intended to be delivered as a unit ready to be applied immediately on site in the pipe. The only item not intended to be included is the detonator, which is mounted in place immediately prior to blowing the charge. The charge includes, apart from explosive, a polymer binder of a more closely defined type and gas blisters preferably in the form of microspheres of glass or plastic and metal or metal oxide powder. The scope of the invention embraces the general configuration of the charge and all components included therein.

  19. Characteristics of Microwave Discharge in a Modified Surfaguide with a Large Diameter

    Institute of Scientific and Technical Information of China (English)

    DING Zhen-Feng(丁振峰); P. Tristant; J. Desmaison; DONG Chuang(董闯); WANG You-Nian(王友年)

    2003-01-01

    The characteristics of the microwave discharge are studied in a modified surfaguide with a large diameter. Experimental results show that there exist three discharging modes, one is the plasma mode, and the others are the waveguide modes. The discharge can jump between one of the waveguide modes and the plasma mode, and the corresponding hysteresis loop is influenced by the discharging pressure. In the higher pressure region, the hysteresis loop is wide enough so that the discharge in each mode is stable. In the middle pressure region, the discharge becomes unstable as a result of the hysteresis loop being sufficiently narrow. When the gas pressure is further decreased, the plasma mode disappears, while the mode jumps between the two waveguide modes always appear and are stable in the discharge region we have explored.

  20. Transarterial chemoembolization for huge hepatocellular carcinoma with diameter over ten centimeters: a large cohort study.

    Science.gov (United States)

    Xue, Tongchun; Le, Fan; Chen, Rongxin; Xie, Xiaoying; Zhang, Lan; Ge, Ningling; Chen, Yi; Wang, Yanhong; Zhang, Boheng; Ye, Shenglong; Ren, Zhenggang

    2015-03-01

    Patients with huge hepatocellular carcinoma >10 cm in diameter represent a special subgroup for treatment. To date, there are few data and little consensus on treatment strategies for huge hepatocellular carcinoma. In this study, we summarized the effects and safety of transarterial chemoembolization for huge hepatocellular carcinoma. A retrospective study was performed based on a large cohort of patients (n = 511) with huge hepatocellular carcinoma who underwent serial transarterial chemoembolization between January 2008 to December 2011 and were followed up until March 2013. We found median survival time was 6.5 months. On multivariate analysis, Child-Pugh class (A versus B) (p huge hepatocellular carcinoma and is recommended as a component of combination therapy. In addition, patients with good liver function and low alpha-fetoprotein levels may acquire greater survival benefits from transarterial chemoembolization.

  1. A photodegradable hexaaza-pentacene molecule for selective dispersion of large-diameter semiconducting carbon nanotubes.

    Science.gov (United States)

    Han, Jie; Ji, Qiyan; Li, Hongbo; Li, Gang; Qiu, Song; Li, Hai-Bei; Zhang, Qichun; Jin, Hehua; Li, Qingwen; Zhang, Jin

    2016-06-08

    Harvesting high-purity semiconducting single-walled carbon nanotubes (s-SWCNTs) with removable dispersants remains a challenge. In this work, we demonstrate that small heteroacene derivatives may serve as promising selective dispersants for sorting s-SWCNTs. A rich N "doped" and thiophene-substituted hexaazapentacene molecule, denoted as 4HP, was found to be more favorable for high-purity s-SWCNTs with large diameters. Importantly, 4HP is photodegradable under 365 nm or blue light, which enables a simple deposition approach for the formation of clean s-SWCNT networks. The as-fabricated thin film transistors show excellent performance with a charge-mobility of 30-80 cm(2) V(-1) s(-1) and an on-off ratio of 10(4)-10(6).

  2. A Literature Review on Heating of Ventilation Air with Large Diameter Earth Tubes in Cold Climates

    Directory of Open Access Journals (Sweden)

    Lili Tan

    2013-07-01

    Full Text Available Earth-air heat exchange (EAHE systems offer the possibility of reducing use of nonrenewable energy for heating ventilation air in cold climates. The number of installations of large diameter (greater than 900 mm EAHE systems reported for cold climates is small. Even less has been reported on their heating performance, but the available information suggests that further rigorous assessment is warranted to determine whether the reported better than expected temperature rise is supported and, if so, the reasons for this. Another concern is the possibility of long-term heat depletion in the surrounding soil, which would affect performance. Only a couple of short-term experimental studies of ground temperature effects of heating with EAHE were found for cool climates. Four articles that addressed ground temperature effects with horizontal ground source heat pump exchangers had conflicting findings regarding heat depletion in the soil.

  3. Effect of sediment on vertical dynamic impedance of rock-socketed pile with large diameter

    Institute of Scientific and Technical Information of China (English)

    俞缙; 蔡燕燕; 吴文兵

    2013-01-01

    Based on the fictitious soil pile model, the effect of sediment on the vertical dynamic impedance of rock-socketed pile with large diameter was theoretically studied by means of Laplace transform technique and impedance function transfer method. Firstly, the sediment under rock-socketed pile was assumed to be fictitious soil pile with the same sectional area. The Rayleigh-Love rode model was used to simulate the rock-socketed pile and the fictitious soil pile with the consideration of the lateral inertial effect of large-diameter pile. The layered surrounding soils and bedrock were modeled by the plane strain model. Then, by virtue of the initial conditions and boundary conditions of the soil pile system, the analytical solution of the vertical dynamic impedance at the head of rock-socketed pile was derived for the arbitrary excitation acting on the pile head. Lastly, based on the presented analytical solution, the effect of sediment properties, bedrock property and lateral inertial effect on the vertical dynamic impedance at rock-socketed pile head were investigated in detail. It is shown that the sediment properties have significant effect on the vertical dynamic impedance at the rock-socketed pile head. The ability of soil-pile system to resist dynamic vertical deformation is weakened with the increase of sediment thickness, but amplified with the increase of shear wave velocity of sediment. The ability of soil pile system to resist dynamic vertical deformation is amplified with the bedrock property improving, but the ability of soil-pile system to resist vertical vibration is weakened with the improvement of bedrock property.

  4. Next Generation Heavy-Lift Launch Vehicle: Large Diameter, Hydrocarbon-Fueled Concepts

    Science.gov (United States)

    Holliday, Jon; Monk, Timothy; Adams, Charles; Campbell, Ricky

    2012-01-01

    With the passage of the 2010 NASA Authorization Act, NASA was directed to begin the development of the Space Launch System (SLS) as a follow-on to the Space Shuttle Program. The SLS is envisioned as a heavy lift launch vehicle that will provide the foundation for future large-scale, beyond low Earth orbit (LEO) missions. Supporting the Mission Concept Review (MCR) milestone, several teams were formed to conduct an initial Requirements Analysis Cycle (RAC). These teams identified several vehicle concept candidates capable of meeting the preliminary system requirements. One such team, dubbed RAC Team 2, was tasked with identifying launch vehicles that are based on large stage diameters (up to the Saturn V S-IC and S-II stage diameters of 33 ft) and utilize high-thrust liquid oxygen (LOX)/RP engines as a First Stage propulsion system. While the trade space for this class of LOX/RP vehicles is relatively large, recent NASA activities (namely the Heavy Lift Launch Vehicle Study in late 2009 and the Heavy Lift Propulsion Technology Study of 2010) examined specific families within this trade space. Although the findings from these studies were incorporated in the Team 2 activity, additional branches of the trade space were examined and alternative approaches to vehicle development were considered. Furthermore, Team 2 set out to define a highly functional, flexible, and cost-effective launch vehicle concept. Utilizing this approach, a versatile two-stage launch vehicle concept was chosen as a preferred option. The preferred vehicle option has the capability to fly in several different configurations (e.g. engine arrangements) that gives this concept an inherent operational flexibility which allows the vehicle to meet a wide range of performance requirements without the need for costly block upgrades. Even still, this concept preserves the option for evolvability should the need arise in future mission scenarios. The foundation of this conceptual design is a focus on low

  5. Modified minimally invasive two-incision total hip arthroplasty using large diameter femoral head

    Directory of Open Access Journals (Sweden)

    Kyung Soon Park

    2012-01-01

    Full Text Available Background: Minimally invasive (MI total hip arthroplasty (THA is an alternative to standard THA, but has created much controversy among orthopedic surgeons. The authors modified the original minimally invasive two-incision THA technique and used large-diameter (32 mm, 36 mm ceramic-on-ceramic articulation. Materials and Methods: One hundred and seventy patients that underwent unilateral MI two-incision THA were retrospectively reviewed, and surgical morbidity, functional recovery, radiological properties, and complications were assessed. Results: Mean Harris hip score (HHS improved from 41.8 to 96.1 at last followup, and mean Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC score from 66.2 to 26.9. The mean lateral opening angle of the acetabular component was 38.2° and the mean stem position was valgus 1.9°. There was an intraoperative femur fracture and one revision surgery due to stem subsidence. No patient had dislocation. Conclusions: Our data suggest that this modified technique combined with large ceramic femoral head is safe and reproducible in terms of achieving proper implant positioning and early functional recovery.

  6. 76 FR 7815 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe (Over 41/2

    Science.gov (United States)

    2011-02-11

    ... Pipe (Over 4\\1/2\\ Inches) From Japan: Extension of Time Limit for Preliminary Results of the... certain large diameter carbon and alloy seamless standard, line, and pressure pipe (over 4\\1/2\\ inches...

  7. Microfabrication of through holes in polydimethylsiloxane (PDMS) sheets using a laser plasma EUV source (Conference Presentation)

    Science.gov (United States)

    Makimura, Tetsuya; Urai, Hikari; Niino, Hiroyuki

    2017-03-01

    Polydimethylsiloxane (PDMS) is a material used for cell culture substrates / bio-chips and micro total analysis systems / lab-on-chips due to its flexibility, chemical / thermo-dynamic stability, bio-compatibility, transparency and moldability. For further development, it is inevitable to develop a technique to fabricate precise three dimensional structures on micrometer-scale at high aspect ratio. In the previous works, we reported a technique for high-quality micromachining of PDMS without chemical modification, by means of photo direct machining using laser plasma EUV sources. In the present work, we have investigated fabrication of through holes. The EUV radiations around 10 nm were generated by irradiation of Ta targets with Nd:YAG laser light (10 ns, 500 mJ/pulse). The generated EUV radiations were focused using an ellipsoidal mirror. It has a narrower incident angle than those in the previous works in order to form a EUV beam with higher directivity, so that higher aspect structures can be fabricated. The focused EUV beam was incident on PDMS sheets with a thickness of 15 micrometers, through holes in a contact mask placed on top of them. Using a contact mask with holes with a diameter of three micrometers, complete through holes with a diameter of two micrometers are fabricated in the PDMS sheet. Using a contact mask with two micrometer holes, however, ablation holes almost reaches to the back side of the PDMS sheet. The fabricated structures can be explained in terms of geometrical optics. Thus, we have developed a technique for micromachining of PDMS sheets at high aspect ratios.

  8. Profile Control by Biased Electrodes in Large Diameter RF Produced Pl asma

    Science.gov (United States)

    Shinohara, Shunjiro; Matsuoka, Norikazu; Yoshinaka, Toshiro

    1998-10-01

    Control of the plasma profile has been carried out, using the voltage biasing method in the large diameter (45 cm) RF (radio frequency) produced plasma in the presence of the uniform magnetic field (less than 1200 G). Under the low filling pressure condition of 0.16 mTorr, changing the biasing voltages to the three individual end plates with concentric circular ring shapes, the radial electron density (about 10^10 cm-3) profile could be changed from the hollow to the peaked one. On the contrary, the nearly flat electron temperature (several eV) profile did not change appreciably. The azimuthal rotation velocity measured by the Mach probe, i.e. directional probe, showed the different radial profiles (but nearly uniform along the axis) depending on the biasing voltage. This velocity became slower with the low magnetic field (less than 200 G) or in the higher pressure regime up to 20 mTorr with the higher electron density. The experimental results by other biasing methods will also be presented.

  9. Multi-objective optimization of crimping of large-diameter welding pipe

    Institute of Scientific and Technical Information of China (English)

    范利锋; 高颖; 云建斌; 李志鹏

    2015-01-01

    Crimping is widely adopted in the production of large-diameter submerged-arc welding pipes. Traditionally, designers obtain the technical parameters for crimping from experience or by trial and error through experiments and the finite element (FE) method. However, it is difficult to achieve ideal crimping quality by these approaches. To resolve this issue, crimping parameter design was investigated by multi-objective optimization. Crimping was simulated using the FE code ABAQUS and the FE model was validated experimentally. A welding pipe made of X80 high-strength pipeline steel was considered as a target object and the optimization problem for its crimping was formulated as a mathematical model and crimping was optimized. A response surface method based on the radial basis function was used to construct a surrogate model; the genetic algorithm NSGA-II was adopted to search for Pareto solutions; grey relational analysis was used to determine the most satisfactory solution from the Pareto solutions. The obtained optimal design of parameters shows good agreement with the initial design and remarkably improves the crimping quality. Thus, the results provide an effective approach for improving crimping quality and reducing design times.

  10. Influence of temperature on the optical system with large diameter off-axis parabolic lenses

    Science.gov (United States)

    Su, Yaru; Ruan, Hao; Liu, Jie

    2016-10-01

    In this work, an optical system with large diameter off-axis parabolic lenses was adopted to achieve diffraction gratings by laser interference exposure. The diffraction wavefront aberration caused by temperature variations was simulated using ZEMAX. Through theoretical analysis and optical simulation, it is proved that the diffraction wavefront aberration of holographic grating caused by the pinhole's location errors (it is assumed that when the displacement of pinhole exists along one axis, the locations of the pinhole along the other two orthogonal axes are in a state of precise adjustment ) is much larger when the displacement occurs along z axis than along the other two axes, and the diffraction wavefront aberration is the smallest when the displacement occurs along x axis. If the ambient temperature changes by 1 degree, the PV value is 0.0631λ when the location of the pinhole changes by 0.121mm along z axis, 0.0034λor 0.0672λ when the location of the pinhole changes by 0.002mm along x axis or 0.03mm along y axis. To reach the diffraction limit (that means the PV value is 0.25λ), the decentering value of the pinhole along z axis should be less than 0.0341mm. In conclusion, the position error along z axis is an important factor to influence the PV value of diffraction grating, and the effect of temperature on the PV value of diffraction grating can be neglected.

  11. The synthesis of large-diameter ZnTe crystal for THz emitting and detection

    Science.gov (United States)

    Liu, Hang; Bai, Wei; Feng, Jiatai; Jie, Wanqi

    2017-10-01

    A high-quality, large-size ZnTe ingot with the diameter of 60 mm and the length of 80 mm were prepared by the modified temperature gradient solvent method, where the Te rich solution acted as both solubility promoter and reactant. Using this method, the crystallization temperature was reduced from 1568 K to 1333 K, plus, the crystal defects could be reduced in some extent due to the lower zinc partial pressure. Few Te inclusions are found in the as-grown ZnTe crystal with the bulk factor less than 0.1%. X-ray diffraction (XRD), infrared transmission microscope, fourier transform infrared (FT-IR) spectrometer, ultraviolet-visible (UV-Vis) spectrophotometer were used to analyze the qualities and properties of the ZnTe crystals. The infrared transmittance over the wavenumber range from 500 to 4000 cm-1 is about 60% and the band gap is about 2.23 eV at the room temperature. The FWHM of the detection pulse with the THz time-domain spectroscopy (THz-TDS) is about 0.34 ps. Besides, both the radiation and detection pulse have a wide frequency distribution about 3 THz at the room temperature. These results strongly indicate that the high-quality ZnTe crystal synthesized by the temperature gradient solvent method is superior for THz device applications.

  12. Guided proliferation and bone-forming functionality on highly ordered large diameter TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruopeng; Wu, Hongliu; Ni, Jiahua, E-mail: jiahua.ni@sjtu.edu.cn; Zhao, Changli; Chen, Yifan; Zheng, Chengjunyi; Zhang, Xiaonong, E-mail: xnzhang@sjtu.edu.cn

    2015-08-01

    The significantly enhanced osteoblast adhesion, proliferation and alkaline phosphatase (ALP) activity were observed on TiO{sub 2} nanotube surface in recent studies in which the scale of nanotube diameter was restricted under 100 nm. In this paper, a series of highly ordered TiO{sub 2} nanotube arrays with larger diameters ranging from 150 nm to 470 nm were fabricated via high voltage anodization. The behaviors of MC3T3-E1 cells in response to the diameter-controlled TiO{sub 2} nanotubes were investigated. A contrast between the trend of proliferation and the trend of cell elongation was observed. The highest cell elongation (nearly 10:1) and the lowest cell number were observed on the TiO{sub 2} nanotube arrays with 150 nm diameter. While, the lowest cell elongation and highest cell number were achieved on the TiO{sub 2} nanotube arrays with 470 nm diameter. Furthermore, the ALP activity peaked on the 150 nm diameter TiO{sub 2} nanotube arrays and decreased dramatically with the increase of nanotube diameter. Thus a narrow range of diameter (100–200 nm) that could induce the greatest bone-forming activity is determined. It is expected that more delicate design of orthopedic implant with regional abduction of cell proliferation or bone forming could be achieved by controlling the diameter of TiO{sub 2} nanotubes. - Highlights: • Improved anodization methods leading to more ordered large diameter TiO{sub 2} nanotubes • Significantly enhanced ALP activity was observed on 150 nm diameter TiO{sub 2} nanotubes. • The highest cell density was observed on 470 nm diameter TiO{sub 2} nanotube arrays. • Similar cell response was observed on the amorphous and anatase phased nanotube surface.

  13. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-01-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed in prior quarters while Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in cast-iron test pipe segments. Efforts in the current quarter continued to focus on Tasks 4-8. Highly valuable lessons were learned from field tests of the 4-inch gas pipe repair robot in cast-iron pipe at Public Service Electric & Gas. (These field tests were conducted and reported last quarter.) These tests identified several design issues which need to be implemented in both the small- and large-diameter

  14. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2004-11-01

    - and large-diameter cast iron repair robots to assure their commercial success. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module in the last quarter 5. In this quarter, work has been concentrated on increasing the nitrogen bladder reservoir volume to allow at least two complete patch inflation/patch setting cycles in the event the sleeve does not set all ratchets in the same row on the first attempt. This problem was observed on a few of the repair sleeves that were recently installed during field tests with the small-diameter robotic system. For Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera) it was observed that it will be necessary to add a stiff brush to push debris away from the immediate vicinity of the bell and spigot joints in mains having low gas velocities. Otherwise, material removed by the cleaning flails (which were found to be very effective in cleaning bell and spigot joints) simply falls to the low side of the pipe and accumulates in a pile. This accumulation can prevent the sleeve from achieving a leak free repair. Similarly, it is also necessary to design a small magnet to capture existing service tap coupons and allow their removal from the inside of the pipe. These coupons were found to cause difficulty in launching and retrieving the small pipe repair robot; one coupon lodged beneath the end of the guide shoe. These new features require redesign of the pipe wall cleaning train and modification to the patch setting train. Task 6 (Design & Build Surface Control and Monitoring System) was previously completed with the control and computer display functions being operated through LabView. However, this must now be re-visited to add control routines for the coupon catcher to be added. This will most likely include a lift-off/place-on magnet translation function. Task 7 (Design

  15. Study on Influensive Factors on Surface Quality and Edges of Through- Holes Bored in Particleboard and MDF

    Directory of Open Access Journals (Sweden)

    Abolghasem Khazaian

    2012-06-01

    Full Text Available In this research, effects of different factors in the CNC machine through- Hole boring of MDF and particleboard were investigated. Variables in boring were selected bit diameter in 3 levels 5,10 and 15 mm, feed speed in 2 levels 0.3 m/min and 0.6 m/min and rotary speed of machine axis in 3 levels 300,1500 and 3000 rmp. The goal of this study was to measure effects of mentioned factors on edge- quality of through- holes made in particle- board and MDF. Results have shown that with all bit diameters used, increasing rotary speed of bit improves smoothness of holes in both sides and boring dusts turned to finer sizes. Increasing feed speed did show positive effect on edge surface quality and lowered burr formation.

  16. Effects of process parameters on numerical control bending process for large diameter thin-walled aluminum alloy tubes

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; YANG He; ZHAN Mei; XU Xu-dong; LI Guang-jun

    2009-01-01

    Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.

  17. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-04-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of old cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed previously. Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in test cast-iron pipe segments. Efforts in the current quarter continued to be focused on Tasks 4-8. Highly valuable lessons were learned from field tests of the 4-inch gas pipe repair robot in cast-iron pipe at Public Service Electric & Gas. (These field tests were conducted and reported previously.) Several design issues were identified which need to be implemented in both the small- and large-diameter repair

  18. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters.

    Science.gov (United States)

    Inoue, Yuki; Hamada, Takaho; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-12-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2).

  19. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters

    CERN Document Server

    Inoue, Yuki; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-01-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for the use at cryogenic temperatures in millimeter wave measurements. Thermally- sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background (CMB) polarization measurements, such as POLARBEAR-2 (PB-2).

  20. A simple multi-seeding approach to growth of large YBCO bulk with a diameter above 53 mm

    Science.gov (United States)

    Tang, Tian-wei; Wu, Dong-jie; Wu, Xing-da; Xu, Ke-Xi

    2015-12-01

    A successful simple multi-seeding approach to growing large size Y-Ba-C-O (YBCO) bulks is reported. Compared with the common single seeding method, our multi-seeding method is more efficient. By using four SmBa2Cu3O7-δ (Sm-123) seeds cut from a large size Sm-Ba-C-O (SmBCO) single domain, large YBCO samples up to 53 mm in diameter could be produced successfully and 100 mm diameter samples can also be grown. Experimental results show that the processing time can be shortened greatly by using this new approach, and the superconducting properties can also be improved. The Hall probe mapping shows that the trapped field distribution of 53 mm diameter multi-seeded sample is homogeneous and the peak value is up to 0.53 T. The magnetic levitation force density reaches to 14.7 N/cm2 (77 K, 0.5 T).

  1. Production of a Uniform ECR Plasma Using Large Diameter Multi Slot Antennas

    OpenAIRE

    上田, 洋子; 寺西, 秀明; 田中, 雅慶; 篠原, 俊二郎; 河合, 良信

    1994-01-01

    A uniform ECR plasma is produced with a multi slot antenna of 280mm in diameter. The radial profile of the ion saturation current density is examined as a function of microwave power and pressure. The radial uniformity of the ion saturation current density is within pm3% over 8 inches in diameter for the input microwave power lkW at pressure of 2mTorr. Furthermore, the deposition of a-Si:H films is attempted on glass substrates using mixture SiH4/He. When the microwave power is increased, the...

  2. Manufacturing Technology Research and Appraisal of Large-Diameter SSAW Pipe Applied to the West-East Pipeline Project

    Institute of Scientific and Technical Information of China (English)

    DingXiaojun; YangZhongwen; XiaXianhua; LiXiaobo

    2005-01-01

    This paper introduced the research and development of large-diameter SSAW pipes applied to West-East Pipeline project as well as domestic acicular ferrite pipeline steel of X70 grade. Its microstructure analysis was performed in comparison with the pipeline steel of a foreign steel plant (SPC). This paper introduced the research of welding procedures prior to SSAW pipe making and some new procedures and technologies used for West-East Pipeline Project, and appraised the practical level of Large-diameter SSAW pipe applied to the West-East Pipeline Project.

  3. Application of Large-diameter and Long-span Micro-expansive Pumping

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this article the high strength micro-expansive concrete that has been applied on big-diameter and long-span steel arch bridge is researched. The applications show that the concrete has some merits,such as good fluidity, low bleeding ratio and no segregation, low slump loss, high early strength and high later strength, micro-expansion etc.

  4. 78 FR 64477 - Welded Large Diameter Line Pipe From Japan: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2013-10-29

    ... or not stenciled. This product is normally produced according to American Petroleum Institute (API... wall thickness measuring greater than 0.688 inches in grades X60 or greater. Having an outside diameter... X52 through X56, and with wall thickness measuring greater than 0.875 inches in grades X60 or...

  5. 75 FR 38989 - Welded Large Diameter Line Pipe From Japan: Notice of Rescission of Antidumping Duty...

    Science.gov (United States)

    2010-07-07

    ... or not stenciled. This product is normally produced according to American Petroleum Institute (API... thickness measuring greater than 0.688 inches in grades X60 or greater. Having an outside diameter greater... through X56, and with wall thickness measuring greater than 0.875 inches in grades X60 or greater....

  6. Fundamental tests and operational suitability tests in the field. Large diameter boring with water jets (2nd report)

    Energy Technology Data Exchange (ETDEWEB)

    Oga, Kotaro; Higuchi, Kiyoshi; Uehara, Masabumi

    1987-09-25

    The application test of large diameter boring in coal seams assisted with water jet was made and two plunger pumps were used. Maximum hydraulic pressure were 300Kg/cm/sup 2/ and 700Kg/cm/sup 2/ and maximum flow rate were 140l/min and 47l/min respectively. Jet water was injected from each nozzle through the pressure resistant hose. Basic test and application test results in Taiheiyo and Akabira mines were summarized as follows: lengths of boreholes were 38 to 78 m and bored diameters were 30 to 70cm. The bored diameter depended on the coal zone hardness and the in-situ stress and indicated similar tendency to the previous large diameter boring. Boring speed was 0.14 to 0.33m/min in case of high velocity jet stream and 0.09m/min at the large diameter boring. Two miners can set and withdraw the boring equipments including the drilling work. (7 figs, 8 tabs, 6 refs)

  7. Multiple Small Diameter Drillings Increase Femoral Neck Stability Compared with Single Large Diameter Femoral Head Core Decompression Technique for Avascular Necrosis of the Femoral Head.

    Science.gov (United States)

    Brown, Philip J; Mannava, Sandeep; Seyler, Thorsten M; Plate, Johannes F; Van Sikes, Charles; Stitzel, Joel D; Lang, Jason E

    2016-10-26

    Femoral head core decompression is an efficacious joint-preserving procedure for treatment of early stage avascular necrosis. However, postoperative fractures have been described which may be related to the decompression technique used. Femoral head decompressions were performed on 12 matched human cadaveric femora comparing large 8mm single bore versus multiple 3mm small drilling techniques. Ultimate failure strength of the femora was tested using a servo-hydraulic material testing system. Ultimate load to failure was compared between the different decompression techniques using two paired ANCOVA linear regression models. Prior to biomechanical testing and after the intervention, volumetric bone mineral density was determined using quantitative computed tomography to account for variation between cadaveric samples and to assess the amount of bone disruption by the core decompression. Core decompression, using the small diameter bore and multiple drilling technique, withstood significantly greater load prior to failure compared with the single large bore technique after adjustment for bone mineral density (pcore decompression techniques. When considering core decompression for the treatment of early stage avascular necrosis, the multiple small bore technique removed less bone volume, thereby potentially leading to higher load to failure.

  8. 78 FR 64475 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe (Over 41/2

    Science.gov (United States)

    2013-10-29

    ... triple or quadruple certify the pipes by meeting the metallurgical requirements and performing the... ASTM A-106 pressure pipes and triple or quadruple certified pipes in large diameters is for use as oil... serves as a final reminder to importers of their responsibility under 19 CFR 351.402(f)(2) to file a...

  9. 76 FR 47555 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Japan...

    Science.gov (United States)

    2011-08-05

    ... triple or quadruple certify the pipes by meeting the metallurgical requirements and performing the... ASTM A-106 pressure pipes and triple or quadruple certified pipes in large diameters is for use as oil... regard to the excluded products listed above, the Department will not instruct U.S. Customs and Border...

  10. 78 FR 3916 - Certain Welded Large Diameter Line Pipe From Japan; Notice of Commission Determination To Conduct...

    Science.gov (United States)

    2013-01-17

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Welded Large Diameter Line Pipe From Japan; Notice of Commission Determination To Conduct... will be established and announced at a later date. For further information concerning the conduct of...

  11. An experimental study on counter current flow limitation in annular narrow gaps with large diameter

    Energy Technology Data Exchange (ETDEWEB)

    Park, Rae Joon; Jeong, Ji Whan; Lee, Sung Jin; Cho, Young Ro; Ha, Kwang Sun; Kim, Sang Baik; Kim, Hee Dong [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-04-01

    The present study intends to carry out CCFL experiment with the same gap size as the CHFG facility and suggest an empirical correlation in order to provide basic information useful to development of an empirical critical-power correlation. The present facility consists of water accumulator tank, test section, DC pump, air regulator, valves and sensors. Air and water are used as working fluids. The experiments are carried out at the atmospheric pressure. Differential pressure between the gap ends, liquid and gas phase flow rates, temperature, lower plenum pressure are measured.Measured values are expressed in terms of Wallis' parameter using gap size as a characteristic length. There is a big difference between the present experimental results and the Koizumi et al.'s results, but the present experimental results are very similar to the Richter et al.'s results. The present results agree well with the Osakabe and Kawasaki's results. In comparison of present experiments with the Koizumi et al.'s experiments, gap thickness is similar, but the diameter of the present is bigger than that of Koizumi et al.'s experiments. In comparison of present experiments with the Richter et al.'s experiments, diameter is similar, but the gap thickness of the present is smaller than that of Richter et al.'s experiments. It is judged from these results that correlation development on CCFL to consider gap thickness is reasonable at similar condition of diameter.The developed correlation will be used to develop the CHFG model. 36 refs., 26 figs., 7 tabs. (Author)

  12. Aerodynamic optimisation of a multirotor wind energy system with a large diameter tower

    Energy Technology Data Exchange (ETDEWEB)

    Dick, E.

    1987-01-01

    The positioning of windrotors in the vicinity of a tower with a comparable diameter is analysed. It is shown that an optimum positioning exists, leading to an energy increase on the rotors of about 25%, due to the acceleration of the flow by the tower, with an acceptable irregularity of the flow through the windrotors. Furthermore, it is shown that on a realistic system with ten windrotors, the cost of the tower can be compensated by the increase in energy production due to the tower concentration effect and due to the increase of wind velocity with height.

  13. Measurements of an ion beam diameter extracted into air through a large-bore metal capillary

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Y.; Umigishi, M. [Graduate School of Humanities and Sciences, Nara Women’s University, Nara 630-8506 (Japan); Ishii, K.; Ogawa, H. [Department of Physics, Nara Women’s University, Nara 630-8506 (Japan)

    2015-07-01

    To extract an ion beam into air, the technique using a single macro-capillary has been paid attention. We have expanded the bore of the metal capillary up to 500 μm∅ inlet diameter to increase the beam intensity and have measured the intensity distributions of the extracted 3 MeV proton beam. Furthermore, we have tilted the capillary angle and measured the intensity distributions of the ion beam. In this article, we will present the experimental results together with the simulation which takes the tilt angles of the capillary into account.

  14. Crystal-melt interface shape of Czochralski-grown large diameter germanium crystals

    Science.gov (United States)

    Roth, M.; Azoulay, M.; Gafni, G.; Mizrachi, M.

    1990-01-01

    Crystal-melt interface shapes of 100 to 200 mm diameter 111-line Ge grown by the Czochralski technique have been examined using the method of fast withdrawal from the melt. Initially, the interface shape is convex, then transforms gradually into a sigmoidal shape, becomes nearly planar at about one third of the final crystal length, and finally assumes a concave profile with progressively increasing curvature. The nearly planar interface has a double-facet structure, with an annular facet at the edge of the crystal in addition to the central (111) facet. Formation of the annular facet is accompanied by a giant oscillation of the pull rate when the maximum average pull rate is exceeded. Such oscillation is detrimental to crystal quality, since it introduces a region of high dislocation density. An average pull rate maximum of 2 cm/h has been found to allow for a smooth growth of 200 mm diameter crystals. The origin of the pull rate perturbation is discussed in terms of an instantaneous change in the equilibrium shape of the meniscus.

  15. Stress corrosion failure of large diameter pressure pipelines of prestressed concrete

    Energy Technology Data Exchange (ETDEWEB)

    Valiente, A. [Universidad Politecnico de Madrid (Spain). Dpto. de Ciencia de Materiales

    2001-07-01

    The failure of a 1.5 m diameter prestressed concrete line for water supply was examined. The water pressure opened a hole of 0.5 m{sup 2} in the pipe wall by breaking the concrete into fragments and by tensile severing of a number of coils of the wire winding. Flexural and tensile testing of samples of the broken materials showed no damage to the concrete, but showed significant losses of strength and ductility in the prestressing steel wire. The SEM analysis of the external and fracture surfaces of the circumferential wires revealed shallow cracking and corroded areas as expected from a stress corrosion cracking process. The failure analysis presented in this paper shows that such a process was able to exhaust the damage tolerance of the affected tube until the pipeline burst under the work pressures. (author)

  16. U-PHOS Project: Development of a Large Diameter Pulsating Heat Pipe Experiment on board REXUS 22

    Science.gov (United States)

    Nannipieri, P.; Anichini, M.; Barsocchi, L.; Becatti, G.; Buoni, L.; Celi, F.; Catarsi, A.; Di Giorgio, P.; Fattibene, P.; Ferrato, E.; Guardati, P.; Mancini, E.; Meoni, G.; Nesti, F.; Piacquadio, S.; Pratelli, E.; Quadrelli, L.; Viglione, A. S.; Zanaboni, F.; Mameli, M.; Baronti, F.; Fanucci, L.; Marcuccio, S.; Bartoli, C.; Di Marco, P.; Bianco, N.; Marengo, M.; Filippeschi, S.

    2017-01-01

    U-PHOS Project aims at analysing and characterising the behaviour of a large diameter Pulsating Heat Pipe (PHP) on board REXUS 22 sounding rocket. A PHP is a passive thermal control device where the heat is efficiently transported by means of the self-sustained oscillatory fluid motion driven by the phase change phenomena. Since, in milli-gravity conditions, buoyancy forces become less intense, the PHP diameter may be increased still maintaining the slug/plug typical flow pattern. Consequently, the PHP heat power capability may be increased too. U-PHOS aims at proving that a large diameter PHP effectively works in milli-g conditions by characterizing its thermal response during a sounding rocket flight. The actual PHP tube is made of aluminum (3 mm inner diameter, filled with FC-72), heated at the evaporator by a compact electrical resistance, cooled at the condenser by a Phase Change Material (PCM) embedded in a metallic foam. The tube wall temperatures are recorded by means of Fibre Bragg Grating (FBG) sensors; the local fluid pressure is acquired by means of a pressure transducer. The present work intends to report the actual status of the project, focusing in particular on the experiment improvements with respect to the previous campaign.

  17. Structural concepts for very large (400-meter-diameter) solar concentrators

    Science.gov (United States)

    Mikulas, Martin M., Jr.; Hedgepeth, John M.

    1989-01-01

    A general discussion of various types of large space structures is presented. A brief overview of the history of space structures is presented to provide insight into the current state-of-the art. Finally, the results of a structural study to assess the viability of very large solar concentrators are presented. These results include weight, stiffness, part count, and in-space construction time.

  18. STATE OF THE ART OF DRILLING LARGE DIAMETER BOREHOLES FOR DEPOSITION OF HIGH LEVEL WASTE AND SPENT NUCLEAR FUEL

    Directory of Open Access Journals (Sweden)

    Trpimir Kujundžić

    2012-07-01

    Full Text Available Deep geological disposal is internationally recognized as the safest and most sustainable option for the long-term management of high-level radioactive waste. Mainly, clay rock, salt rock and crystalline rock are being considered as possible host rocks. Different geological environment in different countries led to the various repository concepts. Main feature of the most matured repository concept is that canisters with spent nuclear fuel are emplaced in vertical or horizontal large diameter deposition holes. Drilling technology of the deposition holes depends on repository concept and geological and geomechanical characteristics of the rock. The deposition holes are mechanically excavated since drill & blast is not a possible method due to requirements on final geometry like surface roughness etc. Different methods of drilling large diameter boreholes for deposition of high-level waste and spent nuclear fuel are described. Comparison of methods is made considering performance and particularities in technology.

  19. Long-Term Prognosis for Patients with Kawasaki Disease Complicated by Large Coronary Aneurysm (diameter ≥6 mm)

    Science.gov (United States)

    Bang, Ji Seok; Kwon, Bo Sang; Song, Mi Kyung; An, Hyo Soon; Song, Young Whan; Bae, Eun Jung; Noh, Chung Il

    2017-01-01

    Background and Objectives Some patients with Kawasaki disease (KD) develop large coronary aneurysms and subsequent coronary stenosis or obstruction, leading to ischemic heart disease. This study examined the long-term outcomes of patients with KD complicated by large coronary aneurysms. Subjects and Methods The medical records of 71 patients (53 men and 18 women) diagnosed with large coronary aneurysms (diameter ≥6 mm) between December 1986 and December 2013 were retrospectively reviewed from our institutional database. Results The mean age at onset was 4.6±3.3 years, and the mean follow-up duration was 12.5±6.9 years. Maximum coronary artery internal diameter ranged from 6.1 to 25 mm. Giant coronary aneurysms occurred in 48 patients and coronary aneurysms 6-8 mm in diameter developed in 23 patients. Coronary stenosis and/or complete occlusion occurred in 30 patients (42.3%). Catheter and/or surgical interventions (mean: 1.5 interventions, range: 1-5 interventions) were performed in 20 patients (28.2%), 9 months to 18 years after KD onset, resulting in 33.7% cumulative coronary intervention rates at 20 years after onset. There were no differences in cumulative coronary intervention rates between two coronary aneurysm groups (6-8 mm vs. ≥8 mm). Myocardial infarction occurred in 7 patients with a giant aneurysm and there was one death. Conclusions Long-term survival of patients with KD complicated by large coronary aneurysm was good even though 28.2% of patients underwent multiple catheter or surgical interventions. Careful follow-up is also necessary in KD patients with coronary aneurysms 6-8 mm in diameter, such as those with giant aneurysms. PMID:28765744

  20. Large-diameter compression arteries as a possible facilitating factor for trigeminal neuralgia: analysis of axial and radial diffusivity

    OpenAIRE

    2016-01-01

    Background Neurovascular compression (NVC) of the trigeminal nerve is associated with trigeminal neuralgia (TN). Some arteries that compress the trigeminal nerve are large, while others are small. This study evaluated the influence of diameter of compression arteries (DCA) on NVC with and without TN using axial diffusivity (AD) and radial diffusivity (RD) of magnetic resonance (MR) imaging. Methods Fifty TN patients with unilateral NVC, 50 asymptomatic patients with unilateral NVC, and 50 hea...

  1. Use of the method of Boolean models to study different methods of drilling wells of large diameter

    Energy Technology Data Exchange (ETDEWEB)

    Selivanov, A.N.; Ryabinin, A.I.

    1981-01-01

    A description is made of the method of statistical modeling using the method of Boolean models as an example of processing and analyzing the results of drilling wells of large diameter by different methods. It is indicated that this method as compared to traditional methods of multiple-factor analysis with comparatively small volume of experimental data makes it possible to obtain a complete qualitative and quantitative characterization of the studied phenomenon.

  2. IN-SITU TEST EXPERIMENTAL RESEARCH ON LEAKAGE OF LARGE DIAMETER PRE-STRESSED CONCRETE CYLINDER PIPE (PCCP

    Directory of Open Access Journals (Sweden)

    Jianjun Luo

    2016-10-01

    Full Text Available In recent years, a big number of large diameter pre-stressed concrete cylinder pipe (PCCP lines have been applied to the Mid-route of the South-to-North Water Transfer Project. However, the leakage problem of PCCP causes annually heavy economic losses to our country. In such a context of situation, how to detect leaks rapidly and precisely after pipes appear cracks in water supply system has great significance. Based on the study and analysis of the characteristic structure of large diameter PCCP, a new leak detection system using fiber Bragg grating sensors, which can capture signals of water pressure change, is proposed. The feasibility, reliability and practicability of the system could be acceptable according to data achieved from in–situ tests. Moreover, the leak detection system can monitor in real-time of dynamic change of water pressure. The equations of the leakage quantity and water pressure have been presented in this paper, which can provide technical guidelines for large diameter PCCP lines maintenance.

  3. Soil-Structure Interaction For Nonslender, Large-Diameter Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal

    Strong political and industrial forces, especially in Northern Europe, support the development of new technologies as well as improvements of existing technologies within the field of renewable energy. Offshore wind power is a domestic, sustainable and largely untapped energy resource. Today, the...

  4. A Snapshot of Present Research at AAU and DTU on Large-Diameter Piles in Coarse-Grained Materials

    DEFF Research Database (Denmark)

    Leth, C. T.; Sørensen, Søren Peder Hyldal; Klinkvort, Rasmus Tofte

    2012-01-01

    Large-diameter (4 to 6 m) monopiles are often used as foundations for offshore wind turbines. The monopiles are subjected to large horizontal forces and overturning moments and they are traditionally designed based on the p-y curve method. The p-y curves recommended in offshore design regulations...... conducted at Aalborg University (AAU) and at the Technical University of Denmark (DTU). The piles have been investigated by means of physical and numerical modelling. The former consists of both centrifuge tests and tests in a so-called pressure tank (1G tests but with an applied overburden pressure...

  5. Numerical Study of Piping Limits for Installation of Large Diameter Buckets in Layered Sand

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Thilsted, C.L.

    2010-01-01

    The bucket foundations, often referred as ‘suction caissons’, are large cylindrical structures, typically made in steel. The bucket foundations have the potential to be the cost-effective option for offshore wind turbines, if suction assisted penetration is employed. Suction installation may cause...... formation of piping channels, which break down the hydraulic seal and prevent further installation. This paper presents a numerical study of failure limits during suction installation in respect to both homogenous and layered soil profile. A numerical flow analysis is performed to determine the hydraulic...... gradients developing in response to applied suction and the results are presented as simple closed form solutions useful for evaluation of suction thresholds against piping. These close form solutions are compared with large scale model test, performed in a natural seabed at a test site in Frederikshavn...

  6. Numerical Study of Piping Limits for Installation of Large Diameter Buckets in Layered Sand

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Thilsted, C.L.

    2010-01-01

    The bucket foundations, often referred as ‘suction caissons’, are large cylindrical structures, typically made in steel. The bucket foundations have the potential to be the cost-effective option for offshore wind turbines, if suction assisted penetration is employed. Suction installation may cause...... formation of piping channels, which break down the hydraulic seal and prevent further installation. This paper presents a numerical study of failure limits during suction installation in respect to both homogenous and layered soil profile. A numerical flow analysis is performed to determine the hydraulic...... gradients developing in response to applied suction and the results are presented as simple closed form solutions useful for evaluation of suction thresholds against piping. These close form solutions are compared with large scale model test, performed in a natural seabed at a test site in Frederikshavn...

  7. Strain-Based Design Methodology of Large Diameter Grade X80 Linepipe

    Energy Technology Data Exchange (ETDEWEB)

    Lower, Mark D. [ORNL

    2014-04-01

    Continuous growth in energy demand is driving oil and natural gas production to areas that are often located far from major markets where the terrain is prone to earthquakes, landslides, and other types of ground motion. Transmission pipelines that cross this type of terrain can experience large longitudinal strains and plastic circumferential elongation as the pipeline experiences alignment changes resulting from differential ground movement. Such displacements can potentially impact pipeline safety by adversely affecting structural capacity and leak tight integrity of the linepipe steel. Planning for new long-distance transmission pipelines usually involves consideration of higher strength linepipe steels because their use allows pipeline operators to reduce the overall cost of pipeline construction and increase pipeline throughput by increasing the operating pressure. The design trend for new pipelines in areas prone to ground movement has evolved over the last 10 years from a stress-based design approach to a strain-based design (SBD) approach to further realize the cost benefits from using higher strength linepipe steels. This report presents an overview of SBD for pipelines subjected to large longitudinal strain and high internal pressure with emphasis on the tensile strain capacity of high-strength microalloyed linepipe steel. The technical basis for this report involved engineering analysis and examination of the mechanical behavior of Grade X80 linepipe steel in both the longitudinal and circumferential directions. Testing was conducted to assess effects on material processing including as-rolled, expanded, and heat treatment processing intended to simulate coating application. Elastic-plastic and low-cycle fatigue analyses were also performed with varying internal pressures. Proposed SBD models discussed in this report are based on classical plasticity theory and account for material anisotropy, triaxial strain, and microstructural damage effects

  8. Soil-Structure Interaction for Non-Slender, Large-Diameter Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal

    conducted. The initial part of p-y curves for non-slender piles has been investigated by means of numerical modelling. The general behaviour of eccentrically loaded non-slender piles has been investigated by physical modelling. These tests have been conducted in the pressure tank at Aalborg University....... Hence, the application of an overburden pressure is possible. The timescale of the backfill process and the compaction of soil material backfilled around piles in storm conditions have been investigated by means of large-scale physical modelling....

  9. The spatial distribution of pollutants in pipe-scale of large-diameter pipelines in a drinking water distribution system.

    Science.gov (United States)

    Liu, Jingqing; Chen, Huanyu; Yao, Lingdan; Wei, Zongyuan; Lou, Liping; Shan, Yonggui; Endalkachew, Sahle-Demessie; Mallikarjuna, Nadagouda; Hu, Baolan; Zhou, Xiaoyan

    2016-11-05

    In large-diameter drinking water pipelines, spatial differences in hydraulic and physiochemical conditions may also result in spatial variations in pipe corrosion, biofilm growth and pollutant accumulation. In this article, the spatial distributions of various metals and organic contaminants in two 19-year-old grey cast iron pipes which had an internal diameter of 600mm (DN600), were investigated and analyzed by Atomic Absorption Spectrometry, Gas Chromatography-Mass Spectrometry, Energy Dispersive Spectrometer, X-ray Diffraction, etc. The spatial distribution of heavy metals varied significantly across the pipe section, and iron, manganese, lead, copper, and chromium were highest in concentration in the upper portion pipe-scales. However, the highest aluminum and zinc content was detected in the lower portion pipe-scales. Apart from some common types of hydrocarbons formed by microbial metabolites, there were also some microalgae metabolites and exogenous contaminants accumulated in pipe-scale, which also exhibited high diversity between different spatial locations. The spatial distributions of the physical and chemical properties of pipe-scale and contaminants were quite different in large-diameter pipes. The finding put forward higher requirements on the research method about drinking water distribution system chemical safety. And the scientific community need understand trend and dynamics of drinking water pipe systems better.

  10. Four-plate piezoelectric actuator driving a large-diameter special optical fiber for nonlinear optical microendoscopy.

    Science.gov (United States)

    Wang, Ying; Li, Zhi; Liang, Xiaobao; Fu, Ling

    2016-08-22

    In nonlinear optical microendoscope (NOME), a fiber with excellent optical characteristics and a miniature scanning mechanism at the distal end are two key components. Double-clad fibers (DCFs) and double-clad photonic crystal fibers (DCPCFs) have shown great optical characteristics but limited vibration amplitude due to large diameter. Besides reducing the damping of fiber cantilever, optimizing the structural of the actuator for lower energy dissipation also contributes to better driving capability. This paper presented an optimized actuator for driving a particular fiber cantilever in the view point of energy. Firstly, deformation energy of a bending fiber cantilever operating in resonant mode is investigated. Secondly, strain and stress analyses revealed that the four-plate actuator achieved lower energy dissipation. Then, finite-element simulations showed that the large-diameter fiber yielded an adequate vibration amplitude driven by a four-plate actuator, which was confirmed by experiments of our home-made four-plate actuator prototypes. Additionally, a NOME based on a DCPCF with a diameter of 350 μm driven by four-plate piezoelectric actuator has been developed. The NOME can excite and collect intrinsic second-harmonic and two-photon fluorescence signals with the excitation power of 10-30 mW and an adequate field of view of 200 μm, which suggest great potential applications in neuroscience and clinical diagnoses.

  11. Forming limits under multi-index constraints in NC bending of aluminum alloy thin-walled tubes with large diameters

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With increasing diameters of aluminum alloy thin-walled tubes (AATTs), the tube forming limits, i.e. the minimum bending factors, and their predictions under multi-index constraints including wrinkling, thinning and flattening have been being a key problem to be urgently solved for improving tube forming potential in numerical control (NC) bending processes of AATTs with large diameters. Thus in this paper, a search algorithm of the forming limits is put forward based on a 3D elastic-plastic finite element (FE) model and a wrinkling energy prediction model for the bending processes under axial compression loading (ACL) or not. This algorithm enables to be considered the effects of process parameter combinations including die, friction parameters on the multi-indices. Based on this algorithm, the forming limits of the different size tubes are obtained, and the roles of the process parameter combinations in enabling the limit bending processes are also revealed. The followings are found: the first, within the appropriate ranges of friction and clearances between the different dies and the tubes enabling the bending processes with smaller bending factors, the ACL enables the tube limit bending processes after a decrease of the mandrel ball thickness and diameters; then, without considering the effects of the tube geometry sizes on the tube constitutive equations, the forming limits will be decided by the limit thinning values for the tubes with diameters smaller than 80 mm, while the wrinkling for the tubes with diameters no less than 80 mm. The forming limits obtained from this algorithm are smaller than the analytical results, and reduced by 57.39%; the last, the roles of the process parameter combinations in enabling the limit bending processes are verified by experimental results.

  12. Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter.

    Science.gov (United States)

    Huang, Cheng-Wei; Tu, Hsien-Tang; Chuang, Chun-Yi; Chang, Cheng-Siu; Chou, Hsi-Hsien; Lee, Ming-Tsung; Huang, Chuan-Fu

    2017-07-14

    OBJECTIVE Stereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs. METHODS Between 2000 and 2014, 35 patients with large VSs, defined as having both a single dimension > 3 cm and a volume > 10 cm(3), underwent Gamma Knife radiosurgery (GKRS). Nine patients (25.7%) had previously undergone resection. The median total volume covered in this group of patients was 14.8 cm(3) (range 10.3-24.5 cm(3)). The median tumor margin dose was 11 Gy (range 10-12 Gy). RESULTS The median follow-up duration was 48 months (range 6-156 months). All 35 patients had regular MRI follow-up examinations. Twenty tumors (57.1%) had a volume reduction of greater than 50%, 5 (14.3%) had a volume reduction of 15%-50%, 5 (14.3%) were stable in size (volume change 3 cm and a volume > 10 cm(3) and tolerable mass effect can be managed satisfactorily with GKRS. Tumor volume ≥ 15 cm(3) is a significant factor predicting poor tumor control following GKRS.

  13. Direct Detection of Planets Orbiting Large Angular Diameter Stars: Sensitivity of an Internally-Occulting Space-Based Coronagraph

    CERN Document Server

    Crepp, Justin R; Ge, Jian

    2009-01-01

    High-contrast imaging observations of large angular diameter stars enable complementary science questions to be addressed compared to the baseline goals of proposed missions like the Terrestrial Planet Finder-Coronagraph, New World's Observer, and others. Such targets however present a practical problem in that finite stellar size results in unwanted starlight reaching the detector, which degrades contrast. In this paper, we quantify the sensitivity, in terms of contrast, of an internally-occulting, space-based coronagraph as a function of stellar angular diameter, from unresolved dwarfs to the largest evolved stars. Our calculations show that an assortment of band-limited image masks can accommodate a diverse set of observations to help maximize mission scientific return. We discuss two applications based on the results: the spectro-photometric study of planets already discovered with the radial velocity technique to orbit evolved stars, which we elucidate with the example of Pollux b, and the direct detecti...

  14. Development of Exterior Anti-corrosion Coating Production Line for Large Diameter Hot Bent Pipes

    Institute of Scientific and Technical Information of China (English)

    JiaoRuyi; ZhangYing

    2004-01-01

    The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti-corrosion method with cost efficiency, environment friendliness and stable coating quality. The quality of the coating on the bent pipe fully meets the requirements of the current national and industrial standards. The application of the technology has filled the gap in the bent pipe anti-corrosion coating area of China, and leads the world technologically. With this technology the coating quality of the bent pipe has greatly improved, resulting in significant social and economic benefits. With the use of the technology in various large scale pipeline projects such as the “West to East Gas Pipeline Project”, it will exhibite a greater potential in the future pipeline projects with a broad application prospect.

  15. Electrospun vascular scaffold for cellularized small diameter blood vessels: A preclinical large animal study.

    Science.gov (United States)

    Ju, Young Min; Ahn, Hyunhee; Arenas-Herrera, Juan; Kim, Cheil; Abolbashari, Mehran; Atala, Anthony; Yoo, James J; Lee, Sang Jin

    2017-09-01

    The strategy of vascular tissue engineering is to create a vascular substitute by combining autologous vascular cells with a tubular-shaped biodegradable scaffold. We have previously developed a novel electrospun bilayered vascular scaffold that provides proper biological and biomechanical properties as well as structural configuration. In this study, we investigated the clinical feasibility of a cellularized vascular scaffold in a preclinical large animal model. We fabricated the cellularized vascular construct with autologous endothelial progenitor cell (EPC)-derived endothelial cells (ECs) and smooth muscle cells (SMCs) followed by a pulsatile bioreactor preconditioning. This fully cellularized vascular construct was tested in a sheep carotid arterial interposition model. After preconditioning, confluent and mature EC and SMC layers in the scaffold were achieved. The cellularized constructs sustained the structural integrity with a high degree of graft patency without eliciting an inflammatory response over the course of the 6-month period in sheep. Moreover, the matured EC coverage on the lumen and a thick smooth muscle layer were formed at 6months after transplantation. We demonstrated that electrospun bilayered vascular scaffolds in conjunction with autologous vascular cells may be a clinically applicable alternative to traditional prosthetic vascular graft substitutes. This study demonstrates the utility of tissue engineering to provide platform technologies for rehabilitation of patients recovering from severe, devastating cardiovascular diseases. The long-term goal is to provide alternatives to vascular grafting using bioengineered blood vessels derived from an autologous cell source with a functionalized vascular scaffold. This novel bilayered vascular construct for engineering blood vessels is designed to offer "off-the-shelf" availability for clinical translation. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. A simple multi-seeding approach to growth of large YBCO bulk with a diameter above 53 mm

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Tian-wei, E-mail: danyangttw@shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China); Wu, Dong-jie [Department of Physics, Shanghai University, Shanghai 200444 (China); Wu, Xing-da [School of Information Engineering, Guangdong Medical College, Zhanjiang 524023 (China); Xu, Ke-Xi, E-mail: kxxu@staff.shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China)

    2015-12-15

    Highlights: • We used Nd-123 cold seeding technique to produce batch Sm-123 seed crystals in air. • We successfully fabricated 53 mm, 75 mm and 100 mm YBCO bulk by multi-seeding method. • Batched Sm-123 seeds are effective in controlling the crystal growth. • The multi-seeded sample has better superconducting properties. • Our method is very simple, reliable and time-saving compared with other techniques. - Abstract: A successful simple multi-seeding approach to growing large size Y–Ba–C–O (YBCO) bulks is reported. Compared with the common single seeding method, our multi-seeding method is more efficient. By using four SmBa{sub 2}Cu{sub 3}O{sub 7-δ} (Sm-123) seeds cut from a large size Sm–Ba–C–O (SmBCO) single domain, large YBCO samples up to 53 mm in diameter could be produced successfully and 100 mm diameter samples can also be grown. Experimental results show that the processing time can be shortened greatly by using this new approach, and the superconducting properties can also be improved. The Hall probe mapping shows that the trapped field distribution of 53 mm diameter multi-seeded sample is homogeneous and the peak value is up to 0.53 T. The magnetic levitation force density reaches to 14.7 N/cm{sup 2} (77 K, 0.5 T).

  17. Utility of anteroposterior diameter ratio of tumor and abdomen for laparoscopic approach for radical nephrectomy in large renal masses.

    Science.gov (United States)

    Yadav, Priyank; Srivastava, Devarshi; Arakere, Sachin; Gupta, Shashikant; Aga, Pallavi; Mandhani, Anil

    2017-08-07

    Laparoscopic radical nephrectomy (LRN) is now increasingly done for tumors larger than 10 cm. Despite selection of favorable cases, LRN may not be successful due to lack of adequate working space with large tumors. We describe a new feature on Contrast Enhanced Computed Tomography (CECT) abdomen to predict feasibility of LRN for large renal masses between 10 and 15 cm. From January 2005 to December 2015, renal tumors between 10 and 15 cm were selected retrospectively for LRN. Patients with retroperitoneal lymphadenopathy, Inferior vena cava (IVC) thrombus and involvement of adjacent organs were excluded. Anteroposterior (AP) diameter ratio of renal tumor and abdomen (APROTA) was calculated by dividing the maximum AP diameter of tumor along with normal renal parenchyma, by the AP diameter of abdomen on CECT. The patients were stratified into two groups: Group A (successful LRN) and Group B (conversion to open surgery) and outcomes were compared. The reasons for conversion were also noted. Of 29 patients, 16 (55.2%) had successful LRN (Group A), while 13 (44.8%) had conversion to open surgery (group B). The median tumor size in Group A was 11.3 ± 1.8 cm and in Group B was 13.6 ± 1.26 cm. Eleven of 13 patients had conversion due to large tumor size causing failure to progress. Two conversions were due to bleeding and injury to the colon each. There was a significant difference in the APROTA in group A and B [0.43 ± 0.09 in group A and 0.64 ± 0.14 in group B (p = 0.0001)]. Patients with APROTA of more than 0.65 are unlikely to have successful outcome with LRN.

  18. Translation of cell therapies to the clinic: characteristics of cell suspensions in large-diameter injection cannulae.

    Science.gov (United States)

    Torres, Eduardo M; Trigano, Matthieu; Dunnett, Stephen B

    2015-01-01

    With the use of cell replacement therapies as a realistic prospect for conditions such as Parkinson's and Huntington's diseases, the logistics of the delivery of cell suspensions to deep brain targets is a topic for consideration. Because of the large cannulae required for such procedures, we need to consider the behavior of cell suspensions within the cannulae if we are to ensure that the injected cells are distributed as intended within the target tissue. We have investigated the behavior of primary embryonic cell suspensions of neural tissue, in cannulae of different diameters, using a protocol designed to mimic the handling and injection of cells during clinical application. Internal cannula diameter had a large effect on the distribution of cells during their dispensation from the syringe. In vertical or near vertical cannulae, cells settled toward the tip of the needle, and were dispensed unevenly, with the majority of cells emerging in the first 10-20% of the injectate. In horizontal or near-horizontal cannulae, we observed the opposite effect, such that few cells were dispensed in the first 80% of the injectate, and the majority emerged in the final 10-20%. Use of a glass cannula showed that the results obtained using the horizontal cannula were caused by settling and adherence of the cells on the side of the cannulae, such that during dispensation, the overlying, cell-free solution was dispensed first, prior to the emergence of the cells. We show that the behavior of cells in such cannulae is affected by the cannula diameter, and by the material of the cannula itself. In horizontal cannulae, uneven expulsion of cells from the needle can be ameliorated by regular rotation of the cannula during the procedure. We discuss the potential impact of these observations on the translation of cell therapies to the clinic.

  19. Vortex-induced vibration of a tube array with a large pitch-to-diameter ratio value

    Directory of Open Access Journals (Sweden)

    Bin Jiang

    2016-06-01

    Full Text Available To study the vortex-induced vibration behaviors of tube arrays with large pitch-to-diameter ratio values, an experiment has been conducted by testing the responses of an elastically mounted tube in a fixed normal triangular tube array with five rows and a pitch-to-diameter ratio value of 2.5 in a water tunnel subjected to cross-flow. The amplitude curves, power spectral density, and response frequencies were obtained in both in-line and transverse directions through the experiment. The results show that the responses obtained from the in-line direction are quite different from those obtained from the transverse direction. In the in-line vibration, there were two excitation regions, yet in the transverse vibration, there was only one excitation region. Moreover, in the in-line vibration, two obvious prominent peaks can be observed in the power spectral density of the vibration signal. The second prominent peak is a subharmonic peak. The frequency corresponding to the subharmonic peak was nearly twice as high as that corresponding to the first peak. However, in the transverse vibration, only a single broad peak existed in the power spectral density of the vibration signal. The hysteresis and the “lock-in” phenomena appeared in both the in-line and transverse vibrations. The results of study are beneficial for designing and operating devices mounted with large pitch-to-diameter ratio tube arrays, and for further research on the vortex-induced vibration of tube arrays.

  20. The spatial distribution of pollutants in pipe-scale of large-diameter pipelines in a drinking water distribution system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingqing [College of Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); Chen, Huanyu [College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Binhai Industrial Technology Research Institute of Zhejiang University, Tianjin 300000 (China); Yao, Lingdan; Wei, Zongyuan [College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Lou, Liping, E-mail: loulp@zju.edu.cn [College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Shan, Yonggui; Endalkachew, Sahle-Demessie; Mallikarjuna, Nadagouda [Environmental Protection Agency, Office of Research and Development, NRMRL, Cincinnati, OH 45220 (United States); Hu, Baolan [College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhou, Xiaoyan [Shaoxing Water Environmental Science Institute Co. Ltd, Zhejiang 312000 (China)

    2016-11-05

    Highlights: • First investigating the spatial distribution of pollutants in pipe-scale. • Spatial distribution of heavy metals indicated their sources were different. • Three main factors effete the distribution of pollutants. • Organic deposits mainly included microbial and microalgae metabolites. - Abstract: In large-diameter drinking water pipelines, spatial differences in hydraulic and physiochemical conditions may also result in spatial variations in pipe corrosion, biofilm growth and pollutant accumulation. In this article, the spatial distributions of various metals and organic contaminants in two 19-year-old grey cast iron pipes which had an internal diameter of 600 mm (DN600), were investigated and analyzed by Atomic Absorption Spectrometry, Gas Chromatography–Mass Spectrometry, Energy Dispersive Spectrometer, X-ray Diffraction, etc. The spatial distribution of heavy metals varied significantly across the pipe section, and iron, manganese, lead, copper, and chromium were highest in concentration in the upper portion pipe-scales. However, the highest aluminum and zinc content was detected in the lower portion pipe-scales. Apart from some common types of hydrocarbons formed by microbial metabolites, there were also some microalgae metabolites and exogenous contaminants accumulated in pipe-scale, which also exhibited high diversity between different spatial locations. The spatial distributions of the physical and chemical properties of pipe-scale and contaminants were quite different in large-diameter pipes. The finding put forward higher requirements on the research method about drinking water distribution system chemical safety. And the scientific community need understand trend and dynamics of drinking water pipe systems better.

  1. Soil Plug Effect Prediction and Pile Driveability Analysis for Large-Diameter Steel Piles in Ocean Engineering

    Institute of Scientific and Technical Information of China (English)

    LIU Run; YAN Shu-wang; LI Zhi-hua

    2009-01-01

    Long steel piles with large diameters have been more widely used in the field of ocean engineering.Owing to the pile with a large diameter,soil plug development during pile driving has great influences on pile driveability and beating capacity.The response of soil plug developed inside the open-ended pipe pile during the dynamic condition of pile-driving is different from the response under the static condition of loading during service.This paper addresses the former aspect.A numerical procedure for soil plng effect prediction and pile driveability analysis is proposed and described.By taking into consideration of the pile dimension effect on side and tip resistance,this approach introduces a dimensional coefficient to the conventional static equilibrium equations for the plug differential unit and proposes an improved static equity method for the plug effect prediction.At the same time,this approach introduces a simplified model by use of one-dimensional stress wave equation to simulate the interaction between soft ping and pile inner wall.The proposed approach has been applied in practical engineering analyses.Results show that the calculated plug effect and pile driveability based on the proposed approach agree well with the observed data.

  2. Optimizing loading path and die linetype of large length-to-diameter ratio metal stator screw lining hydroforming

    Institute of Scientific and Technical Information of China (English)

    祝效华; 石昌帅; 童华

    2015-01-01

    In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on the elastic-plasticity theory, and under the consideration of the effect of tube size, material mechanical parameters, friction coefficient and loading paths, the external pressure plastic forming mechanical model of metal stator screw lining is established, to study the optimal loading path of metal stator lining tube hydroforming process. The results show that wall thickness reduction of the external pressure tube hydroforming (THF) is about 4%, and three evaluation criteria of metal stator screw lining forming quality are presented: fillet stick mold coefficient, thickness relative error and forming quality coefficient. The smaller the three criteria are, the better the forming quality is. Each indicator has a trend of increase with the loading rate reducing, and the adjustment laws of die arc transition zone equidistance profile curve are acquired for improving tube forming quality. Hence, the research results prove the feasibility of external pressure THF used for processing high-accuracy large length-to-diameter ratio metal stator screw lining, and provide theoretical basis for designing new kind of stator structure which has better performance and longer service life.

  3. Easy fabrication of thin membranes with through holes. Application to protein patterning.

    Directory of Open Access Journals (Sweden)

    Thomas Masters

    Full Text Available Since protein patterning on 2D surfaces has emerged as an important tool in cell biology, the development of easy patterning methods has gained importance in biology labs. In this paper we present a simple, rapid and reliable technique to fabricate thin layers of UV curable polymer with through holes. These membranes are as easy to fabricate as microcontact printing stamps and can be readily used for stencil patterning. We show how this microfabrication scheme allows highly reproducible and highly homogeneous protein patterning with micron sized resolution on surfaces as large as 10 cm(2. Using these stencils, fragile proteins were patterned without loss of function in a fully hydrated state. We further demonstrate how intricate patterns of multiple proteins can be achieved by stacking the stencil membranes. We termed this approach microserigraphy.

  4. Void fraction and flow regime in adiabatic upward two-phase flow in large diameter vertical pipes

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, J.P.; Sawant, P.; Paranjape, S.; Ozar, B.; Hibiki, T. [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States); Ishii, M., E-mail: ishii@purdue.ed [Purdue University, School of Nuclear Engineering, 400 Central Dr., West Lafayette, IN 47907-2017 (United States)

    2009-12-15

    In pipes with very large diameters, slug bubbles cannot exist. For this reason, the characteristics of two-phase flow in large pipes are much different than those in small pipes. Knowledge of these characteristics is essential for the prediction of the flow in new nuclear reactor designs which include a large chimney to promote natural circulation. Two of the key parameters in the prediction of the flow are the void fraction and flow regime. Void fraction measurements were made in a vertical tube with diameter of 0.15 m and length of 4.4 m. Superficial gas and liquid velocities ranged from 0.1 to 5.1 m/s and from 0.01 to 2.0 m/s, respectively. The measured void fractions ranged from 0.02 to 0.83. Electrical impedance void meters at four axial locations were used to measure the void fraction. This data was verified through comparison with previous data sets and models. The temporal variation in the void fraction signal was used to characterize the flow regime through use of the Cumulative Probability Density Function (CPDF). The CPDF of the signal was used with a Kohonen Self-Organized Map (SOM) to classify the flow regimes at each measurement port. The three flow regimes used were termed bubbly, cap-bubbly, and churn flow. The resulting flow regime maps matched well with the maps developed previously through other methods. Further, the flow regime maps matched well with the criteria which were proposed based on criteria.

  5. A new approach of extracting embolized venous catheters using a large-diameter steerable sheath under biplane fluoroscopy.

    Science.gov (United States)

    Strohmer, Bernhard; Altenberger, Johann; Pichler, Maximilian

    2012-01-01

    To report the efficacy of a new percutaneous technique for extraction of embolized catheters, five female patients (62 ± 14 years) referred to our institution were analyzed. With the combination of a large-diameter steerable sheath with a sizeable snare system, three dislodged Port-A-Cath tubes and two ventriculoatrial shunts were retrieved successfully. Mean procedure time was 51 ± 23 min, biplane fluoroscopy time was 22 ± 21 min, and dose area product was 1188 ± 992 dGy cm(2). Percutaneous extraction of embolized venous catheters is highly effective with the help of this novel, self-assembled system. The presented technique provides major advantages with respect to three-dimensional steerability and should be considered for complex cases.

  6. Development of manufacturing process for large-diameter composite monofilaments by pyrolysis of resin-impregnated carbon-fiber bundles

    Science.gov (United States)

    Bradshaw, W. G.; Pinoli, P. C.; Vidoz, A. E.

    1972-01-01

    Large diameter, carbon-carbon composite, monofilaments were produced from the pyrolysis of organic precursor resins reinforced with high-strenght carbon fibers. The mechanical properties were measured before and after pyrolysis and the results were correlated with the properties of the constituents. The composite resulting from the combination of Thornel 75 and GW-173 resin precursor produced the highest tensile strength. The importance of matching strain-to-failure of fibers and matrix to obtain all the potential reinforcement of fibers is discussed. Methods are described to reduce, within the carbonaceous matrix, pyrolysis flaws which tend to reduce the composite strength. Preliminary studies are described which demonstrated the feasibility of fiber-matrix copyrolysis to alleviate matrix cracking and provide an improved matrix-fiber interfacial bonding.

  7. Brazilian device for lapidating large diameter non-lubricated metal seated plug valves for the gas and oil segment

    Energy Technology Data Exchange (ETDEWEB)

    Leite da Silva, Osmar Jose [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This work is related to a PETROBRAS patent, which defines an alternative technology for maintenance of valves, which are frequently used in the Oil and Gas segment. Until the development of this device, there were no reliable alternatives for the maintenance available at the Brazilian market, thus these valves had to be sent abroad to be repaired. Normally, the maintenance becomes impracticable, due to the high cost and long periods required to accomplish the whole process (send/repair/return). These drawbacks were a decisive impulse to the development of research process, which resulted in the equipment presented here. The Brazilian device for lapidating large diameter metal seated plug valves, that ensures the tightness reliability of these equipment, is being successfully used at PETROBRAS refineries. (author)

  8. Interface of components with large ratio of altitude to diameter formed by laminated pouring and accumulated liquid forging technology

    Institute of Scientific and Technical Information of China (English)

    姜巨福; 罗守靖; 王迎

    2003-01-01

    Based on the experiment of laminated pouring and accumulated liquid forging of 2A12 aluminum alloy,interface bonding of formed component with large altitude to dimeter ratio of altitude to diameter was investigated by means of SEM and Instron tensile tester.The results show that the method of laminated pouring and accumulated liquid forging can be used for forming components with large ratio.Pouring temperature,reheated temperature of die,pressure,pouring layers and standing time are all important technique parameters that influence the mechanical properties.When pouring temperature is 740℃,reheated temperature of die is 480℃,pressure is 500 kN,pouring layers are three and standing time is 5s,the mechanical properties of interface are the optimum ones,microstructure is equiaxed crystal and tensile fracture has character of dimple.There are three kinds of bonding,which are melting bonding,part melting bonding and mechanical bonding.And the interface of the melting bonding possesses the best mechanical properties.

  9. Guided proliferation and bone-forming functionality on highly ordered large diameter TiO2 nanotube arrays.

    Science.gov (United States)

    Zhang, Ruopeng; Wu, Hongliu; Ni, Jiahua; Zhao, Changli; Chen, Yifan; Zheng, Chengjunyi; Zhang, Xiaonong

    2015-08-01

    The significantly enhanced osteoblast adhesion, proliferation and alkaline phosphatase (ALP) activity were observed on TiO2 nanotube surface in recent studies in which the scale of nanotube diameter was restricted under 100 nm. In this paper, a series of highly ordered TiO2 nanotube arrays with larger diameters ranging from 150 nm to 470 nm were fabricated via high voltage anodization. The behaviors of MC3T3-E1 cells in response to the diameter-controlled TiO2 nanotubes were investigated. A contrast between the trend of proliferation and the trend of cell elongation was observed. The highest cell elongation (nearly 10:1) and the lowest cell number were observed on the TiO2 nanotube arrays with 150 nm diameter. While, the lowest cell elongation and highest cell number were achieved on the TiO2 nanotube arrays with 470 nm diameter. Furthermore, the ALP activity peaked on the 150 nm diameter TiO2 nanotube arrays and decreased dramatically with the increase of nanotube diameter. Thus a narrow range of diameter (100-200 nm) that could induce the greatest bone-forming activity is determined. It is expected that more delicate design of orthopedic implant with regional abduction of cell proliferation or bone forming could be achieved by controlling the diameter of TiO2 nanotubes. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Numerical Analyses of Bearing Capacity of Deep-Embedded Large-Diameter Cylindrical Structure on Soft Ground Against Lateral Loads

    Institute of Scientific and Technical Information of China (English)

    LUAN Mao-tian; FAN Qing-lai

    2006-01-01

    Presented in this paper is a three-dimensional plastic limit analysis method of bearing capacity of the deeply-embedded large-diameter cylindrical structure in the cross-anisotropic soft ground. The most likely failure mechanism is assumed to be of a composite rupture surface which is composed of an individual wedge in the passive zone or two wedges in both active and passive zones near the mudline, depending on the separation or bonding state at the interface between the cylindrical structure and neighboring soils in the active wedge, and a truncated spherical slip surface at the base of the cylinder when the structure tends to overturn around a point located on the symmetry axis of the structure. The cylindrical structure and soil interaction system under consideration is also numerically analyzed by the finite element method by virtue of the general-purpose FEM software ABAQUS, in which the soil is assumed to obey tie Hill's criterion of yield. Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM. For the K0-consolidated ground of clays typically with anisotropic undrained strength property, it is indicated through a parametric study that limit analysis without consideration of anisotropy of soil overestimates the lateral ultimate bearing capacity of a deeply-embedded cylindrical structure in soft ground in a certain condition.

  11. Improving Microstructure and Mechanical Properties for Large-Diameter 7075 Aluminum Alloy Ingots by a Forced Convection Stirring Casting Process

    Science.gov (United States)

    Qi, Mingfan; Kang, Yonglin; Zhu, Guoming; Li, Yangde; Li, Weirong

    2017-01-01

    A simple process so-called forced convection stirring casting (FCSC) was proposed to prepare large-diameter 7075 Al alloy ingots. The flow behavior, temperature, and composition fields of the melt in the FCSC process were simulated. The macromorphology, macrosegregation, microstructure, and mechanical properties of the ingots prepared by the FCSC were studied and compared with those prepared by normal casting (NC). The results showed that in the FCS device, the strong convection caused by the axial flow and circular flow rapidly promoted the uniformity of the temperature and composition fields of the melt. Microstructures of the FCSC ingots from the edge to the center were all nearly spherical grains, which were much finer and more uniform than that of the NC ingots. The rotation speed played an important role in the microstructure of the FCSC ingots, and the grains became finer and rounder as the speed increasing. The FCSC process effectively eliminated cracks, improved macrosegregation, and decreased the eutectic phase area fraction and the average grain boundary thickness of ingots. Mechanical properties of the ingots prepared by the FCSC are far better than that of the NC ingots.

  12. Study on the Deformation Measurement of the Cast-In-Place Large-Diameter Pile Using Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2017-03-01

    Full Text Available Compared with conventional piles such as the circle pile, the cast-in-place large-diameter pile (PCC pile has many advantages: the lateral area of PCC pile is larger and the bearing capacity of PCC pile is higher. It is more cost-effective than other piles such as square pile under the same condition. The deformation of the PCC pile is very important for its application. In order to obtain the deformation of the PCC pile, a new type of quasi-distributed optical fiber sensing technology named a fiber Bragg grating (FBG is used to monitor the deformation of the PCC pile. The PCC model pile is made, the packaging process of the PCC model pile and the layout of fiber sensors are designed, and the strains of the PCC model pile based on FBG sensors are monitored. The strain of the PCC pile is analyzed by the static load test. The results show that FBG technology is successfully applied for monitoring the deformation of the PCC pile, the monitoring data is more useful for the PCC pile. It will provide a reference for the engineering applications.

  13. Annealing Behavior of New Micro-defects in p-type Large-diameter CZ-Si Crystal

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    New types of defects in 15.24 cm diameter and 20.32 cm diameter Czochralski silicon crystals were found after SCI cleaning. Their annealing behavior was studied. It was suggested that these defects become larger during high temperature annealing and disappear by annealing at 1250℃.

  14. A study of production/injection data from slim holes and large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K. [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos Hills, CA (United States); Azawa, Fumio [Idemitsu Kosan Co. Ltd., Tokyo (Japan); Gotoh, Hiroki [Idemitsu Oita Geothermal Co. Ltd., Oita (Japan)

    1996-11-01

    Production and injection data from nine slim holes and sixteen large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan were analyzed in order to establish relationships (1) between injectivity and productivity indices, (2) between productivity/injectivity index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. Results are compared with those from the Oguni and Sumikawa fields. A numerical simulator (WELBOR) was used to model the available discharge rate from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter geothermal production wells with liquid feedzones can be predicted using data from slim holes. These results also indicate the importance of proper well design.

  15. Growth of Si Bulk Crystals with Large Diameter Ratio Using Small Crucibles by Creating a Large Low-Temperature Region Inside a Si Melt Contained in an NOC Furnace Developed Using Two Zone Heaters

    Science.gov (United States)

    Nakajima, Kazuo; Ono, Satoshi; Murai, Ryota; Kaneko, Yuzuru

    2016-06-01

    Three zone heaters were generally used for a noncontact crucible (NOC) furnace. For practical reasons a simpler NOC furnace was developed with two zone heaters, which had a carbon heat holder to cover the three roles of each heater. Large low-temperature regions were obtained, and silicon ingots were grown in small crucibles with a large diameter and diameter ratio. Here, the diameter ratio is the ratio of the ingot diameter to the crucible diameter and can be as large as 0.90. The diameter ratio was controlled mainly by the temperature reduction of the first heater. Power changes of the second heater did not have a significant impact on the ingot diameter. Using this NOC furnace, maximum ingot diameters of 28.0, 33.5, and 45.0 cm were obtained using crucibles of 33, 40, and 50 cm in diameter, respectively. The oxygen concentration of the ingots did not strongly depend on the diameter ratio and were always low because convection in the Si melt was markedly suppressed by the carbon heat holder. Moreover, the oxygen concentration of the ingots has a tendency to become lower as the crucible diameter becomes larger.

  16. Verification of the FBR fuel bundle–duct interaction analysis code BAMBOO by the out-of-pile bundle compression test with large diameter pins

    Energy Technology Data Exchange (ETDEWEB)

    Uwaba, Tomoyuki, E-mail: uwaba.tomoyuki@jaea.go.jp [Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Ibaraki 311-1393 (Japan); Ito, Masahiro; Nemoto, Junichi [Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Ibaraki 311-1393 (Japan); Ichikawa, Shoichi [Japan Atomic Energy Agency, 2-1, Shiraki, Tsuruga-shi, Fukui 919-1279 (Japan); Katsuyama, Kozo [Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Ibaraki 311-1393 (Japan)

    2014-09-15

    The BAMBOO computer code was verified by results for the out-of-pile bundle compression test with large diameter pin bundle deformation under the bundle–duct interaction (BDI) condition. The pin diameters of the examined test bundles were 8.5 mm and 10.4 mm, which are targeted as preliminary fuel pin diameters for the upgraded core of the prototype fast breeder reactor (FBR) and for demonstration and commercial FBRs studied in the FaCT project. In the bundle compression test, bundle cross-sectional views were obtained from X-ray computer tomography (CT) images and local parameters of bundle deformation such as pin-to-duct and pin-to-pin clearances were measured by CT image analyses. In the verification, calculation results of bundle deformation obtained by the BAMBOO code analyses were compared with the experimental results from the CT image analyses. The comparison showed that the BAMBOO code reasonably predicts deformation of large diameter pin bundles under the BDI condition by assuming that pin bowing and cladding oval distortion are the major deformation mechanisms, the same as in the case of small diameter pin bundles. In addition, the BAMBOO analysis results confirmed that cladding oval distortion effectively suppresses BDI in large diameter pin bundles as well as in small diameter pin bundles.

  17. Influence of stacking sequence on scattering characteristics of the fundamental anti-symmetric Lamb wave at through holes in composite laminates.

    Science.gov (United States)

    Veidt, Martin; Ng, Ching-Tai

    2011-03-01

    This paper investigates the scattering characteristics of the fundamental anti-symmetric (A(0)) Lamb wave at through holes in composite laminates. Three-dimensional (3D) finite element (FE) simulations and experimental measurements are used to study the physical phenomenon. Unidirectional, bidirectional, and quasi-isotropic composite laminates are considered in the study. The influence of different hole diameter to wavelength aspect ratios and different stacking sequences on wave scattering characteristics are investigated. The results show that amplitudes and directivity distribution of the scattered Lamb wave depend on these parameters. In the case of quasi-isotropic composite laminates, the scattering directivity patterns are dominated by the fiber orientation of the outer layers and are quite different for composite laminates with the same number of laminae but different stacking sequence. The study provides improved physical insight into the scattering phenomena at through holes in composite laminates, which is essential to develop, validate, and optimize guided wave damage detection and characterization techniques.

  18. FGC-15D large-diameter DTH air hammer drilling system and its application in offshore rock-socketed pile hole drilling

    Institute of Scientific and Technical Information of China (English)

    Kun YIN; Jianming PENG; Maosen WANG; Zhanjiang ZHOU

    2006-01-01

    In the past two decades, numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers, great bridges or to retain soil in potential geological hazard areas. However, drilling large-diameter rock-socketed pile holes with conventional drilling method such as rotary drilling or cable tool drilling is time-consuming and the cost is usually very high. In order to drill large-diameter rock-socketed pile holes faster at relatively low cost, the FGC15A large-diameter DTH air hammer drilling system was developed in 1987 and was given the second-class award by Ministry of Geology and Mineral Resources in 1991. Since it was innovated the drilling system has been used in more than twenty important and tough projects on land, and wonderful results were acquired. At the same time the large-diameter DTH air hammer drilling system was improved continuously. The FGC15D is the latest version of the technique.

  19. Large diameter permanent-magnets-expanded plasma source for spontaneous generation of low-energy ion beam.

    Science.gov (United States)

    Takahashi, Kazunori; Suzuki, Tatsuya; Ando, Akira

    2014-02-01

    Diameter of a permanent-magnets-expanded, radiofrequency (rf) plasma source is enlarged up to ∼13 cm for an application to a space propulsion device and tested with being attached to a diffusion chamber. The source is operated at 13.56 MHz 300 W rf power in low-pressure (40 mPa) argon. Measurement of ion energy distribution functions downstream of the source exit shows generation of a supersonic ion beam of about 20 eV. The detailed radial measurements demonstrate that the diameter and energy of the ion beam corresponds to the source tube diameter and the potential difference between the source and downstream plasmas, and that the radial profile of the beam flux is similar to the plasma density profile in the source cavity.

  20. Wushuihe Bridge Large Diameter Bored Pile Construction in Water%舞水河大桥水中大直径钻孔桩施工

    Institute of Scientific and Technical Information of China (English)

    张维远

    2015-01-01

    This article introduced the construction process of the large diameter bored pile of Wushuige Bridge, summarized the construction technology of large diameter bored pile, and discussed the troubleshooting process for bored pile construction.%本文通过舞水河特大桥大口径钻孔桩的施工过程的介绍,对大口径钻孔桩的施工工艺进行了总结,并对钻孔桩施工过程的故障处理进行了探讨。

  1. SAFT and TOFD evaluation for ultrasonic testing of longitudinal welds in large-diameter pipes; SAFT- und TOFD-Auswertung fuer die Ultraschall-Schweissnahtpruefung von laengsnahtgeschweissten Grossrohren

    Energy Technology Data Exchange (ETDEWEB)

    Rieder, Hans; Dillhoefer, Alexander; Spies, Martin [Fraunhofer-Institut fuer Techno- und Wirtschaftsmathematik ITWM, Kaiserslautern (Germany); Graff, Alfred; Orth, Thomas [Salzgitter Mannesmann Forschung GmbH, Duisburg (Germany); Kersting, Thomas [Europipe GmbH, Muelheim an der Ruhr (Germany). Werk Muelheim

    2010-07-01

    The authors present a mobile multichannel system for testing of longitudinal welds in large-diameter tubes. The prototype was designed for in situ inspection of longitudinal welds using transversal and longitudinal waves impacting at an angle from both sides in combined SE and IE operation. The reconstruction and imaging software enables SAFT calculations for all surface curves and superposition of the SAFT reconstructions from both sides into a general image of the weld. This includes superposition of the TOFD test data with a suitable evaluation and assessment concept. Details are presented, as are test results on test pieces for validation and on longitudinal welds in large-diameter tubes. (orig.)

  2. 3D printed multiplexed electrospinning sources for large-scale production of aligned nanofiber mats with small diameter spread

    Science.gov (United States)

    García-López, Erika; Olvera-Trejo, Daniel; Velásquez-García, Luis F.

    2017-10-01

    We report the design, fabrication, and characterization of novel, low-cost, and modular miniaturized nanofiber electrospinning sources for the scalable production of non-woven aligned nanofiber mats with low diameter variation. The devices are monolithic arrays of electrospinning emitters made via stereolithography; the emitters are arranged so each element has an independent line of sight to a rotating collector surface. Linear and zigzag emitter packing were evaluated using a PEO solution with the aim of maximizing the throughput of nanofibers with the smallest diameter and narrowest distribution. Current versus flowrate characterization of the devices showed that for a given flowrate a zigzag array produces more current per emitter than a linear array of the same emitter pitch and array size. In addition, the data demonstrate that larger and denser arrays have a net gain in flow rate per unit of active length. Visual inspection of the devices suggests uniform operation in devices with as many as 17 emitters with 300 μm inner diameter and 1.5 mm emitter gap. Well-aligned nanofiber mats were collected on a rotating drum and characterized; the 17-emitter device produced the same narrow nanofiber distribution (∼81 nm average diameter, ∼17 nm standard deviation) for all tested flow rates, which is strikingly different to the performance shown by 1-emitter sources where the average fiber diameter significantly increased and the statistics notably widened when the flowrate increases. Therefore, the data demonstrate that massively multiplexing the emitters is a viable approach to greatly increase the throughput of non-woven aligned nanofiber mats without sacrificing the statistics of the nanofibers generated. The production of dry nanofibers by the 17-emitter array is estimated at 33.0 mg min‑1 (1.38 mg min‑1 per mm of active length), which compares favorably with the reported multiplexed electrospinning arrays with emitters distributed along a line.

  3. Influence of the clearance on in-vitro tribology of large diameter metal-on-metal articulations pertaining to resurfacing hip implants.

    Science.gov (United States)

    Rieker, Claude B; Schön, Rolf; Konrad, Reto; Liebentritt, Gernot; Gnepf, Patric; Shen, Ming; Roberts, Paul; Grigoris, Peter

    2005-04-01

    Large-diameter metal-on-metal articulations may provide an opportunity for wear reduction in total hip implants because earlier studies have shown that the formation of a fluid film that completely separates the bearing surfaces is theoretically possible. In such a lubrication mode and under ideal conditions, there is theoretically no amount of wear. Studies have suggested that the two primary parameters controlling the lubrication mode are the diameter and the clearance of the articulation. The goal of the present study was to experimentally investigate the influence of these two parameters on the wear behavior of large-diameter metal-on-metal articulations pertaining to resurfacing hip implants. The results of this in vitro investigation showed that longer running-in periods and higher amounts of running-in wear were associated with larger clearances.

  4. PERFORMANCE EVALUATION OF AN INNOVATIVE FIBER REINFORCED GEOPOLYMER SPRAY-APPLIED MORTAR FOR LARGE DIAMETER WASTEWATER MAIN REHABILITATION IN HOUSTON, TX

    Science.gov (United States)

    This report describes the performance evaluation of a fiber reinforced geopolymer spray-applied mortar, which has potential as a structural alternative to traditional open cut techniques used in large-diameter sewer pipes. Geopolymer is a sustainable green material that incorpor...

  5. Diameter-dependent release of a cisplatin pro-drug from small and large functionalized carbon nanotubes.

    Science.gov (United States)

    Muzi, Laura; Ménard-Moyon, Cécilia; Russier, Julie; Li, Jian; Chin, Chee Fei; Ang, Wee Han; Pastorin, Giorgia; Risuleo, Gianfranco; Bianco, Alberto

    2015-03-12

    The use of platinum-based chemotherapeutic drugs in cancer therapy still suffers from severe disadvantages, such as lack of appropriate selectivity for tumor tissues and insurgence of multi-drug resistance. Moreover, drug efficacy can be attenuated by several mechanisms such as premature drug inactivation, reduced drug uptake inside cells and increased drug efflux once internalized. The use of functionalized carbon nanotubes (CNTs) as chemotherapeutic drug delivery systems is a promising strategy to overcome such limitations due to their ability to enhance cellular internalization of poorly permeable drugs and thus increase the drug bioavailability at the diseased site, compared to the free drug. Furthermore, the possibility to encapsulate agents in the nanotubes' inner cavity can protect the drug from early inactivation and their external functionalizable surface is useful for selective targeting. In this study, a hydrophobic platinum(IV) complex was encapsulated within the inner space of two different diameter functionalized multi-walled CNTs (Pt(IV)@CNTs). The behavior of the complexes, compared to the free drug, was investigated on both HeLa human cancer cells and RAW 264.7 murine macrophages. Both CNT samples efficiently induced cell death in HeLa cancer cells 72 hours after the end of exposure to CNTs. Although the larger diameter CNTs were more cytotoxic on HeLa cells compared to both the free drug and the smaller diameter nanotubes, the latter allowed a prolonged release of the encapsulated drug, thus increasing its anticancer efficacy. In contrast, both Pt(IV)@CNT constructs were poorly cytotoxic on macrophages and induced negligible cell activation and no pro-inflammatory cytokine production. Both CNT samples were efficiently internalized by the two types of cells, as demonstrated by transmission electron microscopy observations and flow cytometry analysis. Finally, the platinum levels found in the cells after Pt(IV)@CNT exposure demonstrate that they can

  6. Diameter-dependent release of a cisplatin pro-drug from small and large functionalized carbon nanotubes

    Science.gov (United States)

    Muzi, Laura; Ménard-Moyon, Cécilia; Russier, Julie; Li, Jian; Chin, Chee Fei; Ang, Wee Han; Pastorin, Giorgia; Risuleo, Gianfranco; Bianco, Alberto

    2015-03-01

    The use of platinum-based chemotherapeutic drugs in cancer therapy still suffers from severe disadvantages, such as lack of appropriate selectivity for tumor tissues and insurgence of multi-drug resistance. Moreover, drug efficacy can be attenuated by several mechanisms such as premature drug inactivation, reduced drug uptake inside cells and increased drug efflux once internalized. The use of functionalized carbon nanotubes (CNTs) as chemotherapeutic drug delivery systems is a promising strategy to overcome such limitations due to their ability to enhance cellular internalization of poorly permeable drugs and thus increase the drug bioavailability at the diseased site, compared to the free drug. Furthermore, the possibility to encapsulate agents in the nanotubes' inner cavity can protect the drug from early inactivation and their external functionalizable surface is useful for selective targeting. In this study, a hydrophobic platinum(iv) complex was encapsulated within the inner space of two different diameter functionalized multi-walled CNTs (Pt(iv)@CNTs). The behavior of the complexes, compared to the free drug, was investigated on both HeLa human cancer cells and RAW 264.7 murine macrophages. Both CNT samples efficiently induced cell death in HeLa cancer cells 72 hours after the end of exposure to CNTs. Although the larger diameter CNTs were more cytotoxic on HeLa cells compared to both the free drug and the smaller diameter nanotubes, the latter allowed a prolonged release of the encapsulated drug, thus increasing its anticancer efficacy. In contrast, both Pt(iv)@CNT constructs were poorly cytotoxic on macrophages and induced negligible cell activation and no pro-inflammatory cytokine production. Both CNT samples were efficiently internalized by the two types of cells, as demonstrated by transmission electron microscopy observations and flow cytometry analysis. Finally, the platinum levels found in the cells after Pt(iv)@CNT exposure demonstrate that they can

  7. Method for extracting an equivalent Winkler model of the 3D dynamic soil-structure interaction of large-diameter offshore monopile foundations

    OpenAIRE

    Versteijlen, W.G.; De Oliveira Barbosa, J.M.; Van Dalen, K.N.; Metrikine, A.

    2015-01-01

    The motivation for this work stems from the offshore wind industry, where designers are faced with a discrepancy between the available design methods and the typical dimensions of the offshore wind foundations that call for other design approaches. Throughout the years, much valuable work has been performed in the prediction of long, slender, flexible piles which are most often applied in the field. For the large-diameter rigidly behaving ‘caisson’ foundations, less methods are available. The...

  8. Research into CNC Processing of Large Diameter Thread of Box%箱体大直径螺纹数控加工的研究

    Institute of Scientific and Technical Information of China (English)

    贾坤鑫

    2012-01-01

    箱体大直径螺纹加工是一个难点问题。分析了用丝锥加工螺纹和计算机数控(CNC)螺纹铣削加工的优缺点,提出以UG软件为编程手段,在加工中心上铣削大直径螺纹的具体方法,并进行了实际加工验证,较好地解决了大直径螺纹加工问题。%The processing of large diameter thread of box is a difficult problem. This paper analyzes the advantages and disadvantages of using tap to process the thread and the computer-numeric control (CNC) thread milling,puts forward the concrete methods of milling large diameter thread in CNC processing center using the UG software as programming means,and performs practical processing validation,which solves the problem of large diameter thread processing better.

  9. Research development of high reflecting coating for large-diameter mirror%大口径反射镜高反射膜研究进展

    Institute of Scientific and Technical Information of China (English)

    孙梦至; 王彤彤; 王延超; 刘震; 刘海; 王笑夷; 杨海贵; 高劲松

    2016-01-01

    大口径反射镜是大型反射式光学系统中关键的光学元件,在工作波段的反射率直接决定了光学系统的性能。随着地基、天基观测设备的发展,对大口径反射镜高反射膜提出了更宽的工作波段、更高的反射率、更好的环境适应性等要求。针对这些挑战,各种新的膜系结构、新的镀制方法、新的膜层材料纷纷出现,满足了大口径反射镜高反射膜的各种需求。本文对近些年国内外的大口径反射镜高反射膜研究进展予以综述,并预测大口径反射镜高反膜制备的技术趋势将由铝反射膜向银反射膜、由热蒸发向磁控溅射发展。%Large-diameter mirrors are the key optical elements in large aperture reflective type optical system, and the optical system performance is directly associated with the reflectance in the working wavelength region. With the great development of the ground-based and space-based observing instruments,more critical perform-ance is required for large-diameter mirrors,such as wider wavelength region,higher reflectance,better envi-ronment durability and so on.Kinds of new coating structures,new coating methods,new coating material are emerging to the challenges,meeting the requirements of high reflecting coating for large-diameter mirror.This paper reviews the research development of high reflecting coating for large-diameter mirror home and abroad, and predicts the developing trend for preparing high reflecting coating of large-diameter reflector from Al mirror to Ag mirror as well as from thermal evaporation to magnetron sputtering.

  10. The use of NH3 to promote the production of large-diameter single-walled carbon nanotubes with a narrow (n,m) distribution.

    Science.gov (United States)

    Zhu, Zhen; Jiang, Hua; Susi, Toma; Nasibulin, Albert G; Kauppinen, Esko I

    2011-02-09

    We demonstrate here a simple and effective (n,m)-selective growth of single-walled carbon nanotubes (SWCNTs) in an aerosol floating catalyst chemical vapor deposition (CVD) process by introducing a certain amount of ammonia (NH(3)). Chiralities of carbon nanotubes produced in the presence of 500 ppm NH(3) at 880 °C are narrowly distributed around the major semiconducting (13,12) nanotube with over 90% of SWCNTs having large chiral angles in the range 20°-30°, and nearly 50% in the range 27°-29°. The developed synthesis process enables chiral-selective growth at high temperature for structurally stable carbon nanotubes with large diameters.

  11. Conformal coating by photoresist of sharp corners of anisotropically etched through-holes in silicon

    DEFF Research Database (Denmark)

    Heschel, Matthias; Bouwstra, Siebe

    1997-01-01

    The authors describe a photoresist treatment yielding conformal coating of three-dimensional silicon structures. This even includes the sharp corners of through-holes obtained by anisotropic etching in (100)-silicon. Resist reflow from these corners is avoided by replacing the common baking proce...... procedure with a proper vacuum treatment. The investigated photoresist is Shipley's Eagle 2100 ED, a negative-working electrodeposited photoresist. Electrical frontside to backside interconnections have been made using this photoresist as an etch mask...

  12. Electron backscatter diffraction analysis on the microstructures of electrolytic Cu deposition in the through hole filling process

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.E., E-mail: ceho1975@hotmail.com [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); Liao, C.W. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Pan, C.X. [School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Chen, H.J. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); Kuo, J.C.; Chen, D. [Department of Materials Science and Engineering, National Cheng Kung University, Taiwan, ROC (China)

    2013-10-01

    Through hole (TH) filling by electrolytic Cu deposition has become a critical process for high density interconnection technologies associated with three-dimensional packaging. In this study, the morphological and crystallographic evolutions of the electrolytic Cu TH filling with the plating time (t) were investigated using an optical microscope and a field-emission scanning electron microscope equipped with an electron backscatter diffraction (EBSD) analysis system. The Cu deposition rate in the TH was strongly dependent on t, which was established at a moderate rate of ∼ 0.3 μm/min at t = 40 min–74 min, then dramatically accelerated to ∼ 4 μm/min at t = 74 min–80 min (termed “fast deposition regime”), and subsequently decelerated in the final plating regime (t = 80 min–100 min). EBSD analyses showed that the electrolytic Cu predominantly possessed high-angle grain boundaries with strong coincidence site lattices at ∑3 (60° rotation at <111>) and ∑9 (38.9° rotation at <101>) for all t examined. Interestingly, the [111]‖TD (transverse direction) orientation displayed a relatively strong presence in the initial induction regime, while the [111]‖TD + [101]‖TD orientations with large grain sizes became dominant in the fast deposition regime (i.e., t = 74 min–80 min), and there was a very low concentration of the [111]‖TD orientation in the final deposition regime. This research offered a better understanding of the morphological and crystallographic evolutions in each stage of the electrolytic Cu TH filling. - Highlights: • Through hole (TH) filling by electrolytic Cu deposition • The Cu deposition rate is strongly dependent on the plating time in the THs. • The dominant Cu orientations were [111]‖TD (transverse direction) and [101]‖TD. • Cu possessed high angle grain boundaries with strong coincidence site lattices.

  13. Standard Test Method for Determining Solar or Photopic Reflectance, Transmittance, and Absorptance of Materials Using a Large Diameter Integrating Sphere

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1987-01-01

    1.1 This test method covers the measurement of the absolute total solar or photopic reflectance, transmittance, or absorptance of materials and surfaces. Although there are several applicable test methods employed for determining the optical properties of materials, they are generally useful only for flat, homogeneous, isotropic specimens. Materials that are patterned, textured, corrugated, or are of unusual size cannot be measured accurately using conventional spectrophotometric techniques, or require numerous measurements to obtain a relevant optical value. The purpose of this test method is to provide a means for making accurate optical property measurements of spatially nonuniform materials. 1.2 This test method is applicable to large specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the reflectance of opaque materials and the reflectance and transmittance of semitransparent materials including corrugated fiber-reinforced plastic, ...

  14. Successful endothelialization and remodeling of a cell-free small-diameter arterial graft in a large animal model.

    Science.gov (United States)

    Koobatian, Maxwell T; Row, Sindhu; Smith, Randall J; Koenigsknecht, Carmon; Andreadis, Stelios T; Swartz, Daniel D

    2016-01-01

    The large number of coronary artery bypass procedures necessitates development of off-the-shelf vascular grafts that do not require cell or tissue harvest from patients. However, immediate thrombus formation after implantation due to the absence of a healthy endothelium is very likely. Here we present the successful development of an acellular tissue engineered vessel (A-TEV) based on small intestinal submucosa that was functionalized sequentially with heparin and VEGF. A-TEVs were implanted into the carotid artery of an ovine model demonstrating high patency rates and significant host cell infiltration as early as one week post-implantation. At one month, a confluent and functional endothelium was present and the vascular wall showed significant infiltration of host smooth muscle cells exhibiting vascular contractility in response to vaso-agonists. After three months, the endothelium aligned in the direction of flow and the medial layer comprised of circumferentially aligned smooth muscle cells. A-TEVs demonstrated high elastin and collagen content as well as impressive mechanical properties and vascular contractility comparable to native arteries. This is the first demonstration of successful endothelialization, remodeling, and development of vascular function of a cell-free vascular graft that was implanted in the arterial circulation of a pre-clinical animal model. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. 一种基于Hadoop的大规模图直径算法%A Large Graph Diameter Algorithm Based on Hadoop

    Institute of Scientific and Technical Information of China (English)

    叶强; 孙忠林; 魏永山

    2013-01-01

    To improve the processing efficiency of the large graph with millions nodes, the author proposed a GDH big graph diameter calculation algorithm by studying large graph and distributed framework Hadoop. Firstly,the algorithm calculates nodes with the same radius,all the radius of nodes will be calculated in the last iteration, then large graph diameter be calculated with the number of nodes divided by the sum of nodes radius. The time complexity and space complexity of the algorithm is not big, and experimental results show that it more efficient than the classical diameter estimation algorithm. What’ s more,by analyzing Yahoo and Facebook websites data,it can benefit both web analytics and interpersonal analysis of social network.%为提高具有百万个节点以上的大规模图处理效率,通过研究大规模图和分布式框架Hadoop,提出了GDH大规模图直径算法。算法通过每次计算出半径相同的图节点,直到最后一次迭代求出所有节点的半径,然后用节点半径之和除以节点数算出大规模图直径。算法的时空复杂度不大,并且与经典的直径算法相比,GDH算法的效率高些。经测试雅虎网站和脸谱网站的网页数据,发现该算法可清晰地分析Web图的网页节点和社交图的人际关系。

  16. Heat and fluid flow characteristics of an oval fin-and-tube heat exchanger with large diameters for textile machine dryer

    Science.gov (United States)

    Bae, Kyung Jin; Cha, Dong An; Kwon, Oh Kyung

    2016-11-01

    The objectives of this paper are to develop correlations between heat transfer and pressure drop for oval finned-tube heat exchanger with large diameters (larger than 20 mm) used in a textile machine dryer. Numerical tests using ANSYS CFX are performed for four different parameters; tube size, fin pitch, transverse tube pitch and longitudinal tube pitch. The numerical results showed that the Nusselt number and the friction factor are in a range of -16.2 ~ +3.1 to -7.7 ~ +3.9 %, respectively, compared with experimental results. It was found that the Nusselt number linearly increased with increasing Reynolds number, but the friction factor slightly decreased with increasing Reynolds number. It was also found that the variation of longitudinal tube pitch has little effect on the Nusselt number and friction factor than other parameters (below 2.0 and 2.5 %, respectively). This study proposed a new Nusselt number and friction factor correlation of the oval finned-tube heat exchanger with large diameters for textile machine dryer.

  17. Void fraction development in gas-liquid flow after a U-bend in a vertically upwards serpentine-configuration large-diameter pipe

    Science.gov (United States)

    Almabrok, Almabrok A.; Aliyu, Aliyu M.; Baba, Yahaya D.; Lao, Liyun; Yeung, Hoi

    2017-08-01

    We investigate the effect of a return U-bend on flow behaviour in the vertical upward section of a large-diameter pipe. A wire mesh sensor was employed to study the void fraction distributions at axial distances of 5, 28 and 47 pipe diameters after the upstream bottom bend. The study found that, the bottom bend has considerable impacts on up-flow behaviour. In all conditions, centrifugal action causes appreciable misdistribution in the adjacent straight section. Plots from WMS measurements show that flow asymmetry significantly reduces along the axis at L/D = 47. Regime maps generated from three axial locations showed that, in addition to bubbly, intermittent and annular flows, oscillatory flow occurred particularly when gas and liquid flow rates were relatively low. At this position, mean void fractions were in agreement with those from other large-pipe studies, and comparisons were made with existing void fraction correlations. Among the correlations surveyed, drift flux-type correlations were found to give the best predictive results.

  18. Construction technology of outdoor large diameter water supply PE pipe%室外大口径 PE 给水管道施工工艺探析

    Institute of Scientific and Technical Information of China (English)

    周保安

    2014-01-01

    Along with the development of science and technology and the enhancement of environmental protection consciousness , the green environmental protection building materials gradually respected around the world .At present, the building materials for pipeline laying in China are green building materials of PE pipe , which has no harmful elements .Combined with the construction practice of Hunnan avenue of longitudinal drainage ditch of Hunnan New District in Shenyang City , aimed at the construction problems of outdoor large -diameter PE pipe, construction process and construction points of the outdoor PE large diameter pipeline was briefly introduced , providing the reference for the similar engineering construction .%随着科学技术的发展以及环保意识的增强,绿色环保型建筑材料逐渐得到世界各国的推崇。目前,我国给水管道铺设采用的建筑材料就是绿色建材PE管。针对室外大口径PE给水管的施工问题,本工艺结合沈阳市浑南新区浑南大道纵向给水管道的施工实例,对室外大口径PE给水管道施工工艺、施工要点进行简单介绍,为以后类似的工程施工提供参考。

  19. Research on sub-surface damage and its stress deformation in the process of large aperture and high diameter-to-thickness ratio TMT M3MP

    Science.gov (United States)

    Hu, Hai-xiang; Qi, Erhui; Cole, Glen; Hu, Hai-fei; Luo, Xiao; Zhang, Xue-jun

    2016-10-01

    Large flat mirrors play important roles in large aperture telescopes. However, they also introduce unpredictable problems. The surface errors created during manufacturing, testing, and supporting are all combined during measurement, thus making understanding difficult for diagnosis and treatment. Examining a high diameter-to-thickness ratio flat mirror, TMT M3MP, and its unexpected deformation during processing, we proposed a strain model of subsurface damage to explain the observed phenomenon. We designed a set of experiment, and checked the validity of our diagnosis. On that basis, we theoretical predicted the trend of this strain and its scale effect on Zerodur®, and checked the validity on another piece experimentally. This work guided the grinding-polishing process of M3MP, and will be used as reference for M3M processing as well.

  20. Study on the coal bunker design with large diameter%大直径井底煤仓设计研究

    Institute of Scientific and Technical Information of China (English)

    封金权

    2015-01-01

    针对河南省赵家寨煤矿井底煤仓直径大、煤仓高度比较高,且煤质黏性大,易堵仓等特点,为掌握仓内装煤情况,解决堵仓问题,设计在煤仓两侧分别设置一个观察立眼和观察孔,同时结合布置的空气炮[1],成功地解决了大直径、高煤仓堵仓问题。观察立眼、观察孔与空气炮的联合使用,在国内甚至在国际上尚属首次,该设计为以后煤仓堵仓问题的解决提供了一定的参考意义。%aiming at the character of large diameter and height of the bottom coal bunker in Zhaojiazhai coal mine in Henan Province, and the viscosity of coal is big, and easy to block warehouse etc., to grasp the situation of coal bin, solve the problems of the blocking coal bunker designed a vertical eye observation and observation hole in two sides of coal bunker, combined with the layout of the air cannon, the successful solution of the problem of blocking coal bunker with large diameter, and large height, the combined using of observe vertical eye, observation hole and air guns, even in the world for the ifrst time, provide some reference for the design to solve the problem after the coal warehouse stopping.

  1. Study on Coalmine Large Diameter Engineering Well Drilling%煤矿大口径工程井钻井技术研究

    Institute of Scientific and Technical Information of China (English)

    周兢

    2016-01-01

    煤矿大口径工程井要求井斜小、直径大,其钻井方法可分为反井钻井法和常规钻井法。反井钻井法虽然钻进效率高但对施工设备和工程条件要求苛刻,而常规钻井法集定向钻进、气动潜孔锤钻进、分级扩孔等技术为一体,具有适用范围广、施工成本低等特点。利用常规钻井法施工煤矿大口径工程井存在着扩孔钻头机械破岩能量不足和钻井液携岩能力弱等问题,提出通过加大钻机扭矩、优化扩孔分级方案以及采用气举反循环钻进工艺来解决上述问题,而且给出了采用气举反循环工艺施工典型煤矿大口径工程井的主要设备配置方案。%The coalmine large diameter engineering well requires small deviation and large diameter. The drilling method can be divid⁃ed into raise boring drilling and conventional drilling. The raise boring drilling although has high efficiency, but harsh demands on con⁃struction equipment and engineering specifications. While the conventional drilling has set directional drilling, pneumatic DTH drill⁃ing, graded reaming into one, thus wide range of application and low construction cost. Moreover, the paper has pointed out issues of conventional drilling have insufficient reamer bit mechanical rock breaking energy, weaker drilling fluid carrying capacity etc. Thus drill torque increasing, reaming graded scheme optimizing and air-lift reverse circulation drilling using put forward to solve above is⁃sues;also main equipment configuration scheme for air-lift reverse circulation drilling to construct typical coalmine large diameter en⁃gineering well provided.

  2. The Fabrication and Application of a PDMS Micro Through-Holes Mask in Electrochemical Micromanufacturing

    Directory of Open Access Journals (Sweden)

    Xiaolei Chen

    2014-08-01

    Full Text Available The electrochemical micromanufacturing process, as a key micromanufacturing technology, plays an important role in diverse industries. In this paper, polydimethylsiloxane (PDMS is employed as a mask in the electrochemical micromanufacture of microstructures because of its chemical resistance, low cost, flexibility, and high molding capability. A new method for fabricating a PDMS micro through-holes mask is proposed. In this method, a thin resist film is employed to enhance the adhesion between the substrate and the SU-8 pillar array which is used as a mold. A vacuum-aided process is used to inject the PDMS gel into the SU-8 mold and the PDMS micro through-holes mask can be peeled off from the SU-8 mold when the gel is cured. Experiments were conducted to verify the feasibility of the proposed approach and PDMS microholes of various shapes were obtained. The PDMS mask can then be successfully applied in the electrochemical micromanufacturing process to generate microstructures and microdimple and embossment arrays have been successfully demonstrated. Furthermore, the PDMS mask can be reused, as it is not damaged during the manufacturing process.

  3. Aortic coarctation associated with aortic valve stenosis and mitral regurgitation in an adult patient: a two-stage approach using a large-diameter stent graft.

    Science.gov (United States)

    Novosel, Luka; Perkov, Dražen; Dobrota, Savko; Ćorić, Vedran; Štern Padovan, Ranka

    2014-02-01

    We report a case of a staged surgical and endovascular management in a 62-year-old woman with aortic coarctation associated with aortic valve stenosis and mitral regurgitation. The patient was admitted for severe aortic valve stenosis and mitral valve incompetence. During hospitalization and preoperative imaging, a previously undiagnosed aortic coarctation was discovered. The patient underwent a 2-stage approach that combined a Bentall procedure and mitral valve replacement in the first stage, followed by correction of the aortic coarctation by percutaneous placement of an Advanta V12 large-diameter stent graft (Atrium, Mijdrecht, The Netherlands) which to our knowledge has not been used in an adult patient with this combination of additional cardiac comorbidities. A staged approach combining surgical treatment first and endovascular placement of an Advanta V12 stent graft in the second stage can be effective and safe in adult patients with coarctation of the aorta and additional cardiac comorbidities.

  4. Design and Fabrication of Large Diameter Gradient-Index Lenses for Dual-Band Visible to Short-Wave Infrared Imaging Applications

    Science.gov (United States)

    Visconti, Anthony Joseph

    The fabrication of gradient-index (GRIN) optical elements is quite challenging, which has traditionally restricted their use in many imaging systems; consequently, commercial-level GRIN components usually exist in one particular market or niche application space. One such fabrication technique, ion exchange, is a well-known process used in the chemical strengthening of glass, the fabrication of waveguide devices, and the production of small diameter GRIN optical relay systems. However, the manufacturing of large diameter ion-exchanged GRIN elements has historically been limited by long diffusion times. For example, the diffusion time for a 20 mm diameter radial GRIN lens in commercially available ion exchange glass for small diameter relays, is on the order of a year. The diffusion time can be dramatically reduced by addressing three key ion exchange process parameters; the composition of the glass, the diffusion temperature, and the composition of the salt bath. Experimental work throughout this thesis aims to (1) scale up the ion exchange diffusion process to 20 mm diameters for a fast-diffusing titania silicate glass family in both (2) sodium ion for lithium ion (Na+ for Li+) and lithium ion for sodium ion (Li+ for Na+) exchange directions, while (3) utilizing manufacturing friendly salt bath compositions. In addition, optical design studies have demonstrated that an important benefit of gradient-index elements in imaging systems is the added degree of freedom introduced with a gradient's optical power. However, these studies have not investigated the potential usefulness of GRIN materials in dual-band visible to short-wave infrared (vis-SWIR) imaging systems. The unique chromatic properties of the titania silicate ion exchange glass become a significant degree of freedom in the design process for these color-limited, broadband imaging applications. A single GRIN element can replace a cemented doublet or even a cemented triplet, without loss in overall system

  5. Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly.

    Directory of Open Access Journals (Sweden)

    Andreas Fichtner

    Full Text Available The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica forest by quantifying variation in the intensity of above- (shading and belowground competition (crowding among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.

  6. Effect of high-pressure homogenization preparation on mean globule size and large-diameter tail of oil-in-water injectable emulsions

    Directory of Open Access Journals (Sweden)

    Jie Peng

    2015-12-01

    Full Text Available The effect of different high pressure homogenization energy input parameters on mean diameter droplet size (MDS and droplets with > 5 μm of lipid injectable emulsions were evaluated. All emulsions were prepared at different water bath temperatures or at different rotation speeds and rotor-stator system times, and using different homogenization pressures and numbers of high-pressure system recirculations. The MDS and polydispersity index (PI value of the emulsions were determined using the dynamic light scattering (DLS method, and large-diameter tail assessments were performed using the light-obscuration/single particle optical sensing (LO/SPOS method. Using 1000 bar homogenization pressure and seven recirculations, the energy input parameters related to the rotor-stator system will not have an effect on the final particle size results. When rotor-stator system energy input parameters are fixed, homogenization pressure and recirculation will affect mean particle size and large diameter droplet. Particle size will decrease with increasing homogenization pressure from 400 bar to 1300 bar when homogenization recirculation is fixed; when the homogenization pressure is fixed at 1000 bar, the particle size of both MDS and percent of fat droplets exceeding 5 μm (PFAT5 will decrease with increasing homogenization recirculations, MDS dropped to 173 nm after five cycles and maintained this level, volume-weighted PFAT5 will drop to 0.038% after three cycles, so the “plateau” of MDS will come up later than that of PFAT5, and the optimal particle size is produced when both of them remained at plateau. Excess homogenization recirculation such as nine times under the 1000 bar may lead to PFAT5 increase to 0.060% rather than a decrease; therefore, the high-pressure homogenization procedure is the key factor affecting the particle size distribution of emulsions. Varying storage conditions (4–25°C also influenced particle size, especially the PFAT

  7. High Frequency Welding(HFW) Procedure Selection for API Large Diameter Units%API大管径机组高频焊接工艺的选择

    Institute of Scientific and Technical Information of China (English)

    王琪

    2013-01-01

    During HFW pipe production with diameter greater than 406 mm (16 in),in order to correctly assess and select appropriate welding procedure,in this article,it discussed the difference of contact welding and induction welding from weld quality,energy consumption and other aspects,and emphasized the influence on high frequency contact welding and high frequency induction welding of large diameter units.The results showed that relative to high frequency induction welding,high frequency contact welding is with some advantages,such as weld quality is good,energy saving effect is obvious,it doesn't need the expensive loop,induction coil or a large number of complicated impedor device.The design and maintenance for inside slash mandrel are simple,the breakdown time of replacing the coil and impedor device is shorter and the finished product yield rate is high.In addition,when adopting "reel-to-reel" welding procedure,for contact welding,the output is high and less waste,it can obtain obvious shorter welding angle of V-shaped length and shorter welding area,and easy to control plate edge quality and weld quality.%在生产直径大于406 mm(16 in)高频焊管时,为了能正确评估并选择适合的焊接工艺,从焊缝质量、能耗等方面讨论了接触焊和感应焊的差异,并重点讨论了大管径机组对高频感应焊和高频接触焊的影响.综合分析对比得出,高频接触焊相对感应焊具有焊缝质量好、节能效果明显、不需要昂贵的活套和感应线圈以及复杂的阻抗器装置等优势,感应芯棒设计及维护简单方便,成材率高,并且当采用“卷对卷工艺”时,相对于感应焊,接触焊产量高、废品少,能够获得明显较短的焊接V形区长度和较短的焊接区,易于控制板边质量和焊缝质量.

  8. Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting

    Directory of Open Access Journals (Sweden)

    Xingrui Chen

    2017-05-01

    Full Text Available Traditional fixed-frequency ultrasonic technology and a variable-frequency ultrasonic technology were applied to refine the as-cast microstructure and improve the mechanical properties of a ZK60 (Mg–Zn–Zr alloy during large diameter semi-continuous casting. The acoustic field propagation was obtained by numerical simulation. The microstructure of the as-cast samples was characterized by optical and scanning electron microscopy. The variable-frequency ultrasonic technology shows its outstanding ability in grain refinement compared with traditional fixed-ultrasonic technology. The variable-frequency acoustic field promoted the formation of small α-Mg globular grains and changed the distribution and morphology of β-phases throughout the castings. Ultimate tensile strength and elongation are increased to 280 MPa and 8.9%, respectively, which are 19.1% and 45.9% higher than the values obtained from billets without ultrasonic treatment and are 11.6% and 18.7% higher than fixed-frequency ultrasound treated billets. Different refinement efficiencies appear in different districts of billets attributed to the sound attenuation in melt. The variable-frequency acoustic field improves the refinement effect by enhancing cavitation-enhanced heterogeneous nucleation and dendrite fragmentation effects.

  9. Model Test Research on the End Bearing Behavior of the Large-Diameter Cast-in-Place Concrete Pile for Jointed Rock Mass

    Directory of Open Access Journals (Sweden)

    Jingwei Cai

    2016-01-01

    Full Text Available For large-diameter, cast-in-place concrete piles, the end bearing capacity of a single pile is affected by discontinuous surfaces that exist in natural rock masses when the bearing layer of the pile end is located in the rock layer. In order to study the influence of the jointed dip angle on the bearing characteristics of the pile end, the discrete element models are adopted to simulate the mechanical characteristics of the jointed rock masses, and the model tests of the failure mode of the jointed rock masses were also designed. The results of the numerical calculations and modeling tests show that the joints, which have a filtering effect on the internal stress of the bedrock located at the pile end, change the load transferring paths. And the failure mode of the jointed rock foundation also changes as jointed dip angle changes. The rock located at the pile end generally presents a wedge failure mode. In addition, the Q-S curves obtained by model tests show that the ultimate end bearing capacity of a single pile is influenced by the jointed dip angle. The above results provide an important theoretical basis for how to correctly calculate end resistance for a cast-in-place concrete pile.

  10. Study on Centrifugal Casting for Large Diameter Cast-steel Sleeve%大直径铸钢套筒的离心铸造研究

    Institute of Scientific and Technical Information of China (English)

    符寒光; 邢建东; 赵爱民

    2001-01-01

    The casting method for large diameter cast-steel sleeve in horizontal centrifugal casting machine was described. The process measures of decreasing gas hole and cast crack in sleeve were discussed. The cast-steel sleeve by centrifugal casting has the features of compacted and homogeneous microstructure, high technological yield and low machining allowance. The cost is decreased by more than 20% than that of cast-steel sleeve by c onventional static casting.%主要介绍了卧式离心铸造大直径铸钢套筒的方法,讨论了降低套筒气孔和铸造裂纹的工艺措 施,离心铸造铸钢套筒具有组织致密、均匀、工艺出品率高和铸件加工量少等特点,生产成 本比普通静态铸造降低20%以上,用作铝箔轧机的出口端卷筒,获 得了较好的效果。

  11. Thy1.2 YFP-16 transgenic mouse labels a subset of large-diameter sensory neurons that lack TRPV1 expression.

    Directory of Open Access Journals (Sweden)

    Thomas E Taylor-Clark

    Full Text Available The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X(2/3 and TRPM8 channels in Ca2+ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.

  12. Center of Mass Compensation during Gait in Hip Arthroplasty Patients: Comparison between Large Diameter Head Total Hip Arthroplasty and Hip Resurfacing

    Directory of Open Access Journals (Sweden)

    Vicky Bouffard

    2011-01-01

    Full Text Available Objective. To compare center of mass (COM compensation in the frontal and sagittal plane during gait in patients with large diameter head total hip arthroplasty (LDH-THA and hip resurfacing (HR. Design. Observational study. Setting. Outpatient biomechanical laboratory. Participants. Two groups of 12 patients with LDH-THA and HR recruited from a larger randomized study and 11 healthy controls. Interventions. Not applicable. Main Outcome Measures. To compare the distance between the hip prosthetic joint center (HPJC and the COM. The ratio (RHPJC-COM and the variability (CVHPJC-COM were compared between groups. Hip flexor, abductor, and adductor muscle strength was also correlated between groups while radiographic measurements were correlated with the outcome measures. Results. In the frontal plane, HR shows less variability than healthy controls at push-off and toe-off and RHPJC-COM is correlated with the muscle strength ratios (FRABD at heel contact, maximal weight acceptance, and mid stance. In the sagittal plane, LDH-THA has a higher RHPJC-COM than healthy controls at push-off, and CVHPJC-COM is significantly correlated with FRFLEX. Conclusions. One year after surgery, both groups of patients, LDH-THA and HR, demonstrate minor compensations at some specific instant of the gait cycle, in both frontal and sagittal planes. However, their locomotion pattern is similar to the healthy controls.

  13. Final Results from Mexnext-I. Analysis of detailed aerodynamic measurements on a 4.5 m diameter rotor placed in the large German Dutch Wind Tunnel DNW

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G.; Boorsma, K. [Energy research Center of the Netherlands ECN, Petten (Netherlands); Munduate, X. [National Renewable Energy Center, CENER, Pamplona (Spain)

    2013-02-15

    The paper presents the final results from the first phase of IEA Task 29 'Mexnext'. Mexnext was a joint project in which 20 parties from 11 different countries cooperated. The main aim of Mexnext was to analyse the wind tunnel measurements which have been taken in the EU project 'MEXICO'. In the MEXICO project 10 institutes from 6 countries cooperated in doing experiments on an instrumented, three-bladed wind turbine of 4.5 m diameter placed in the 9.5 by 9.5 m{sup 2} open section of the Large Low-speed Facility (LLF) of the test facility DNW (German-Dutch Wind Tunnels). Pressure distributions on the blades were obtained from 148 Kulite pressure sensors, distributed over 5 sections at 25, 35, 60, 82 and 92% radial position respectively. Blade loads were monitored through two strain-gauge bridges at each blade root. Most interesting however are the extensive PIV flow field measurements, which have been taken simultaneously with the pressure and load measurements. As a result of the international collaboration within this task a very thorough analysis of the data could be carried out and a large number of codes were validated not only in terms of loads but also in terms of underlying flow field. The paper will present several results from Mexnext-I, i.e. validation results and conclusion on modelling deficiencies and directions for model improvement. The future plans of the Mexnext consortium are also briefly discussed. Amongst these are Mexnext-II, a project in which also aerodynamic measurements other than MEXICO are included, and 'New MEXICO' in which additional measurement on the MEXICO model are performed.

  14. 大直径钻孔灌注桩的竖向承载性能%Vertical bearing capacity of large-diameter bored pile

    Institute of Scientific and Technical Information of China (English)

    刘念武; 龚晓南; 俞峰

    2015-01-01

    T he self‐balancing test w as conducted on tw o 2 .2 m diameter drilled piles in order to analyze the bearing capacity of large diameter bored piles .The test results were compared with in‐situ test results . Results show that the change of load‐displacement of pile with post‐grouting is slower than pile without post‐grouting .The end resistance reached the limit state when pile tip displacements approached 20 mm (1% D ,D is the pile diameter) .The side resistance increased firstly and maintained a stable trend with the increase of pile‐soil relative displacement .The critical displacement was 1 .5‐3 .0 mm .Post‐grouting can improve the side resistance over a certain depth from the pile tip ,and the improvement in round gravel mixed pebble bed is 18 percent . Resistive loads up and dow n the side of the load cell is different and transformation coefficient is 0 .92 and 0 .91 , respectively . Side resistance and undrained vane‐shear strength has a linear relationship and has a better goodness of fit .The ultimate side resistance of round gravel mixed can be estimated by dynamic sounding (63 .5 kg) hits .%为了分析大直径钻孔灌注桩的承载性能,对2根直径分别为2.2m的钻孔灌注桩开展自平衡试验,将试验结果与原位测试结果进行对比分析.通过对测试结果的分析发现,注浆后荷载箱的向上及向下荷载‐位移曲线的变化更加缓慢,当桩端位移为20 mm(1% D ,其中 D为桩径)左右时,端阻达到极限状态,未注浆桩和注浆桩的极限端阻分别为2834、3561 kPa .桩身侧阻随着桩土相对位移的增大呈先增大后保持稳定的趋势,淤泥质粉土层、黏土夹粉砂层、圆砾混卵石层的侧阻在桩土相对位移为1.5~3.0mm时达到稳定.注浆能够提高桩端以上一定深度的桩身侧阻,圆砾混卵石层中侧阻的提高幅度约为18%.荷载箱上下的侧阻随位移的变化模式不同,未注浆桩

  15. Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty

    Science.gov (United States)

    2013-01-01

    Background and purpose The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. Methods 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5–6.7) years. Results A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. Interpretation ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely. PMID:24171688

  16. 大口径天然气管道音波信号的降噪方法%Noise Reduction for Large-Diameter Gas Pipeline Acoustic Signals

    Institute of Scientific and Technical Information of China (English)

    梁伟; 张来斌; 郭磊

    2012-01-01

    According to the characteristics of nonlinear system when large-diameter gas pipeline runs, lo-cal-projective noise reduction method is used to reduce the strong background noises mixed in acoustic signals. The theoretical basis, the algorithm steps as well as the mathematical model of local-projective noise reduction method are introduced. Furthermore, the key parameters of algorithm, embedding dimension and delay time, are described respectively and calculated by corresponding methods. The original acoustic signals of three different field operation conditions are de-noised, and the results show that the signal-to-noise ratio is increased by 20. 7~38. 2 dB, which illustrates the effective and practical local-projective noise reduction method can realize correct separation of acoustic feature signals from noises.%针对大口径天然气管道运行的非线性系统的特点,利用局部投影降噪方法对高含噪声的音波信号进行降噪处理.介绍了局部投影降噪方法的理论基础、算法步骤和数学模型,对该算法中的关键参数嵌入维数和时间延迟分别进行了说明,并用相应的方法进行求解计算.对现场3种不同工况的原始音波数据进行降噪分析,结果显示信噪比提高了20.7~38.2 dB,说明了局部投影降噪方法对音波信号降噪的有效性和实用性,能实现噪声与特征信号的正确分离.

  17. Heating coil welding technique for connection of large-diameter PE pipes using universally applicable, flexible taped joints; Heizwendelschweissverfahren fuer die Verbindung von PE-Grossrohren mittels universal anwendbarer, flexibler Wickelmuffen

    Energy Technology Data Exchange (ETDEWEB)

    Baudrit, Benjamin; Kraus, Eduard; Heidemeyer, Peter; Bastian, Martin [Sueddeutsche Kunststoff-Zentrum, Wuerzburg (Germany); Kern, Juergen; Neufeld, Wjatscheslaw [Frank und Krah Wickelrohr GmbH, Woelfersheim (Germany)

    2011-07-01

    This research project (Heating coil welding technique for connection of large-diameter PE pipes using universally applicable, flexible taped joints) was carried out by SKZ (Sueddeutsches Kunststoff-Zentrum) in close coopearation with Messrs. Frank and Krah Wickelrohr GmbH with the intention to develop a high-quality, economically efficient joining process for large-diameter pipes. The technique is based on the new technology of heating coil joints which permits the use of any desired joint geometries at acceptable cost. The new technique was validated for joints up to a diameter of 1,000 mm. With the welding parameters calculated in the project, even larger diameter joints are possible in theory.

  18. Construction, Modeling and Testing of a Low-Flow, Large-Diameter Aerosol Flow System for the Study of the Formation and Reactions of Tropospheric Aerosols

    Science.gov (United States)

    Ezell, M. J.; Johnson, S. N.; Yu, Y.; Pokkunuri, P.; Perraud, V.; Bruns, E.; Alexander, M.; Zelenyuk, A.; Dabdub, D.; Finlayson-Pitts, B. J.

    2008-12-01

    A unique, high-volume, low-flow, stainless steel aerosol flow system for the study of the formation and reactions of aerosols relevant to the troposphere has been constructed, modeled and experimentally tested. The total flow tube length is 7.3 m which includes a 1.2 m section used for mixing. The flow tube is equipped with ultraviolet lamps for photolysis. The diameter of 0.45 m results in a smaller surface to volume ratio than is found in many other flow systems and reduces the contribution of wall reactions. The latter is also reduced by frequent cleaning of the flow tube walls which is feasible due to the ease of disassembly of the flow tube. Flow systems present a major advantage over chamber studies in that continuous sampling under stable conditions over long periods of time is possible, increasing the amount of sample available for analysis and permitting a wide variety of analytical techniques to be applied simultaneously. In this system, the large volume (1000 L) and low flow speed (2 cm/minute) result in a residence time of nearly an hour; and equally spaced sampling ports allow for time-resolved measurements of aerosol and gas-phase products. The central features of this system have been modeled using computational fluid dynamics software and experimentally probed using inert gases and aerosols. Instrumentation attached directly to this flow system includes a NOx analyzer, an ozone analyzer, relative humidity and temperature probes, a scanning mobility particle sizer (SMPS) spectrometer, an aerodynamic particle sizer (APS) spectrometer, GC-MS, integrating nephelometer, and FTIR. Particles are collected using impactors and filters, and analyzed by a variety of techniques including FTIR, electrospray ionization mass spectrometry (ESI-MS), atmospheric pressure chemical ionization mass spectrometry (APCI-MS), GC-MS, HPLC-UV and HPLC-MS. In addition, for selected studies, an aerosol mass spectrometer (AMS), a single particle mass spectrometer (SPLAT II) and

  19. Space energy gathering system based on large diameter inflatable thin-film%空间大口径薄膜反射聚能系统

    Institute of Scientific and Technical Information of China (English)

    毛冰晶; 郭倩蕊; 王本欣; 张天湘

    2012-01-01

    能源是航天器能够正常工作的基本保证,太阳能、引力能、真空能等太空即时补给能源是航天器供能的焦点.提出基于大口径薄膜反射的空间聚能系统的研究方案,利用充气式囊状薄膜反射镜结构聚焦太阳能,在焦斑处结合热电转换技术,实现了太阳能的汇集和能量的热电转换,并应用仿真软件模拟得到了不同焦距值的反射面聚焦效果的对比数据,验证了方案的可行性.所提出的以光、热、电三种能量形式为飞行器供能的设想为空间飞行器能源系统的设计提供了新思路和新技术.%Energy is the basic guarantee for spacecraft' s ordinary working. Solar energy, gravitational energy, vacuum energy and other space immediately supply energy for spacecraft have taken the most attention in the scientific community. A space energy gathering system which reflecting and focusing solar energy based on large diameter inflatable thin-film structure was proposed. This system combined inflatable thin-film cystic structure and thermoelectric conversion technology at the focal spot to convert thermal energy into electricity energy. And the energy values focused by the reflectors in different focal lengths were simulated, which verified the feasibility of the scheme. The idea of converting energy for the spacecraft in three modes: light, heat, electricity was proposed. It provides a new idea and new technology for spacecraft system design.

  20. TCDD1100大直径车轮热成形工艺的研究%Thermoforming Process of TCDD1100 Large Diameter Wheel

    Institute of Scientific and Technical Information of China (English)

    张磊; 杜云岗; 白恩泽

    2014-01-01

    TCDD1100车轮是我公司出口土耳其的产品,也是目前我公司出口产品中外径最大的车轮。该车轮结构复杂,即辐板薄且较长,车轮轮辋较重,热成形金属分布和流动相对复杂。%TCDDΦ1100 wheel is our export products in Turkey, also the largest outer diameter wheel for outlet. The wheel has complex structure. The spoke is a long but thin and the wheel rim is heavier. While hot rolling forming, metal distribution and flow is relatively complicated.

  1. A Study of Production/Injection Data from Slim Holes and Large-Diameter Wells at the Okuaizu Geothermal Field, Tohoku, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel Lawrence; Garg, Sabodh K.; Combs, Jim

    2002-06-01

    Discharge from the Okuaizu boreholes is accompanied by in situ boiling. Analysis of cold-water injection and discharge data from the Okuaizu boreholes indicates that the two-phase productivity index is about an order of magnitude smaller than the injectivity index. The latter conclusion is in agreement with analyses of similar data from Oguni, Sumikawa, and Kirishima geothermal fields. A wellbore simulator was used to examine the effect of borehole diameter on the discharge capacity of geothermal boreholes with two-phase feedzones. Based on these analyses, it appears that it should be possible to deduce the discharge characteristics of largediameter wells using test data from slim holes with two-phase feeds.

  2. The applicanion of 3-roll sheet bending machine and roll post-bending machines for production of longitudinal large pipes with corellation diameter/thikness less than 30

    OpenAIRE

    Урядов, Р. В.; Христофоров, А. С.

    2014-01-01

    In this article we introduce based on the experience of longitudinal large pipes production on the Volzhsky pipe plant power parameters calculating and any ideas about a decreasing abilities of our equipment for pipes with high thickness.

  3. Broadband mid-infrared supercontinuum generation in 1-meter-long As2S3-based fiber with ultra-large core diameter.

    Science.gov (United States)

    Zhang, Peiqing; Yang, Peilong; Wang, Xunsi; Wang, Rongping; Dai, Shixun; Nie, Qiuhua

    2016-12-12

    In this study, the supercontinuum (SC) generation in a 1-m-long As2S3 fiber with a 200 μm core diameter was demonstrated experimentally. The high-purity As2S3 fiber we used exhibited very low optical loss with a background loss of approximately 0.1 dB/m at a wavelength of 2-5 μm. SC generation was studied by pumping the fiber at different wavelengths and different peak powers. A strong spectral broadening with a 30 dB spectral flatness spanning from 1.4 to 7.0 µm was obtained when the fiber was pumped with 150 fs short pulses at 5.0 µm. The SC generation in bent fiber was also studied. The result showed that the bending radius of the fiber will significantly affect the SC spectra bandwidth and the output power. The SC spectra in the used fiber could still be maintained when it was bent to a radius of 5 cm.

  4. 大口径PCCP管在软土地基中的应用%Application of Large Diameter PCCP in Soft Soil Foundation

    Institute of Scientific and Technical Information of China (English)

    温晓英; 程子悦; 郭晓光

    2012-01-01

    广州市西江引水工程管径大、压力高,且为双管同槽敷设.主管材采用预应力钢筒混凝土管(PCCP).管道沿线多为淤泥质软土,强度低,压缩性高,流变性强,易产生地基沉降.对其主管材(PCCP)在软土地基中的沉降进行了分析,论述了管道在运行过程中的荷载变化以及容易引起地基沉降的一些因素,说明了地基处理的必要性,并根据管道沿线软土地基的具体情况,对西江引水工程中所采用的几种地基处理方法作了详细介绍,可供类似工程参考.%Guangzhou Xijiang River water diversion project has big pipeline diameter, high pressure and two pipes are laid in the same trench. The main pipe material is prestressed concrete cylinder pipe (PCCP). The soil along the pipeline is mainly silt soft soil with low strength, high compressibility and high flowability, which easily leads to foundation settlement. The settlement of PCCP in soft soil foundation is analyzed. The load change of the pipeline during operation and factors contributing to the settlement are discussed, and the necessity of the treatment of foundation is explained. Based on the specific circumstances of soft soil foundation along the pipeline, several treatment measures taken in Xijiang River water diversion project are introduced to provide reference for the similar projects.

  5. Discussion on Thrust Design of Large Diameter Water Transmission Pipeline%大口径输水管道的止推设计

    Institute of Scientific and Technical Information of China (English)

    温晓英; 程子悦; 冯树健

    2012-01-01

    Xijiang River water diversion project is the lifeline project in Guangzhou City. The project has big pipeline diameter, high pressure and two pipes are laid in the same trench. The main pipe material is prestressed concrete cylinder pipe (PCCP). Because of the big push force at the elbow of two pipes, the thrust design is the key factor ensuring the safety of the whole system, and also one of the emphases and difficulties in the project design. Based on the specific circumstances of Xijiang River water diversion project, such as the big push force, land shortage, short construction period and so on, the thrust form of steel pipe packed by concrete is chosen. The design of the thrust form is introduced to provide reference for the similar projects.%广州市西江引水工程是广州市的生命线工程,其管径大、压力高,且双管同槽敷设.主管材采用预应力钢筒混凝土管(PCCP),由于弯头处双管推力很大,使得弯头处的止推设计成为保证整个输水系统安全的关键因素,也是工程设计的重点和难点之一.对几种常用的止推形式进行分析,并针对西江引水工程推力大、用地紧张、工期短等具体情况,最终确定了钢管外包混凝土的止推形式.对该种止推形式的设计进行了介绍,可供类似工程参考.

  6. Full Depth Freezing Technology of Large Diameter Mine Shaft%煤矿大直径立井全深冻结技术

    Institute of Scientific and Technical Information of China (English)

    王斌; 江恩武; 程志彬

    2014-01-01

    门克庆煤矿副井净直径10 m ,井深755.45 m ,采用全深冻结法施工,冻结深度768m。井筒所穿地层,大部分为白垩系和侏罗系软弱岩层,其中有3层含水层。冻结孔采用主孔+辅助孔布置方式。井筒于2010-10-17正式开机冻结;至同年11月27日,冻结壁交圈;12月6日(开机冻结后49d)试挖;2012-01-02停止冻结。至2012-01-15,井筒安全顺利落底,取得预期效果。%A net diameter of a mine auxiliary shaft in Menkeqing Mine was 10m ,the depth of the shaft was 755.45m and the shaft was constructed with full depth freezing method. The freezing depth of the shaft was 768m. The strata passed through by the shaft mainly were Cretaceous and Jurassic soft rock strata. Among the strata ,there were three aquifers. A main borehole+auxiliary borehole pattern meth‐od was applied to the freezing boreholes. A freezing of the mine shaft was officially started on Oct.17 , 2010 based on the refrigeration machine set turned on. On November 27 of the same year ,a freezing ring of the freezing wall was formed. On December 6 ,2010 ,a trial excavation was conducted in the shaft (after 49 days of the refrigeration machine set was turned on).On January 2 ,2012 ,the freezing operation of the shaft was stopped and on January 15 ,2012 ,the mine shaft was safely and successfully reach on the bottom of the mine shaft with the expected effect.

  7. The John Charnley Award: Metal-on-metal hip resurfacing versus large-diameter head metal-on-metal total hip arthroplasty: a randomized clinical trial.

    Science.gov (United States)

    Garbuz, Donald S; Tanzer, Michael; Greidanus, Nelson V; Masri, Bassam A; Duncan, Clive P

    2010-02-01

    Resurfacing arthroplasty has become an attractive option for young patients who want to maintain a high activity level. One recent study reported modestly increased activity levels for patients with resurfacing compared to standard total hip arthroplasty (THA). We conducted a prospective randomized clinical trial to compare clinical outcomes of resurfacing versus large-head metal-on-metal total hip arthroplasty. We randomized 107 patients deemed eligible for resurfacing arthroplasty to have either resurfacing or standard THA. Patients were assessed for quality-of-life outcomes using the PAT-5D index, WOMAC, SF-36, and UCLA activity score. The minimum followup was 0.8 years (mean, 1.1 years; range, 0.8-2.2 years). Of the 73 patients followed at least one year, both groups reported improvement in quality of life on all outcome measures. There was no difference in quality of life between the two arms in the study. Serum levels of cobalt and chromium were measured in a subset of 30 patients. In both groups cobalt and chromium was elevated compared to baseline. Patients receiving a large-head metal-on-metal total hip had elevated ion levels compared to the resurfacing arm of the study. At 1 year, the median serum cobalt increased 46-fold from baseline in patients in the large-head total hip group, while the median serum chromium increased 10-fold. At 1 year, serum cobalt was 10-fold higher and serum chromium 2.6-fold higher than in the resurfacing arm. Due to these excessively high metal ion levels, the authors recommend against further use of this particular large-head total hip arthroplasty. Level I, randomized clinical trial. See Guidelines for Authors for a complete description of levels of evidence.

  8. Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

    Science.gov (United States)

    Abdul Aziz, M. S.; Abdullah, M. Z.; Khor, C. Y.

    2014-01-01

    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183°C) analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry. PMID:25225638

  9. MWD tool for deep, small diameter boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Buytaert, J.P.R.; Duckworth, A.

    1992-03-17

    This patent describes an apparatus for measuring a drilling parameters while drilling a borehole in an earth formation, wherein the borehole includes a small diameter deep borehole portion and a large diameter upper borehole portion. It includes small diameter drillstring means for drilling the deep borehole portion; sensor means, disposed within the small diameter drillstring means, for measuring a drilling parameter characteristic of the deep portion of the borehole while drilling the deep portion of the borehole and for providing sensor output signals indicative of the measured parameter; an upper drillstring portion extending between the surface of the formation and the small diameter drillstring means, the upper drillstring portion including a large diameter drillstring portion; data transmission means disposed within the large diameter drillstring portion and responsive to the sensor output.

  10. 大头径髋关节假体的理论研究与临床应用%Theoretical research and clinical application of large-diameter femoral head hip prosthesis

    Institute of Scientific and Technical Information of China (English)

    汝鸣; 蔡郑东

    2008-01-01

    A computer-based online search was conducted in PUMMED, English Medical Current Contents (EMCC), China Journal Full-text Database (CJFD), and Wanfang Database to summarize application and research progress of large-diameter femoral head hip prosthesis from January 1995 to January 2008. There were 62 literatures in total. Previous studies reported that when diameter of femoral head hip prosthesis was>32mm, joint worn out remarkably. During recent years, more and more basic and clinical researches demonstrate that diameter of femoral head is not correlated with wear rate; in particular, diameter of femoral head is not related to wear rate of artificial joint made by high cross linked polyethylene, metal, and ceramics. The superiority of large-diameter femoral head hip prosthesis has been paid more attention because of stability and activity. With the enlargement of diameter of femoral head, dislocated incidence decreases remarkably, and improvement of head-neck ratio increases the activity of prosthesis and reduces collision between two prostheses. Recently, large-diameter femoral head hip prosthesis has been widely applied for metal-on-mental hip joint, in particular, for hip resurfacing arthroplasty; in addition, large-diameter femoral head hip prosthesis plays a distinct role in joint replacement.%应用计算机检索Pubmed数据库、西文生物医学期刊文献数据库、中国期刊全文数据库和万方数据库1995-01/2008-01的文献62篇,总结大直径球头人工髋关节临床应用及研究进展.以往认为髋关节假体股骨头直径>32mm时关节磨损将明显增加,近年越来越多的基础和临床研究显示股骨头直径大小与磨损率高低并无必然联系,特别是在高交联聚乙烯、金属、陶瓷等耐磨材料应用于人工关节之后.大头径髋关节假体在关节稳定性和活动度方面的优势已引起重视,研究发现随着股骨头直径的增大,脱位的发生率明显降低,同时头颈比改善增

  11. Optodynamic monitoring of the laser drilling of through-holes in glass ampoules

    Science.gov (United States)

    Petkovsek, Rok; Babnik, Ales; Diaci, Janez

    2006-10-01

    We present an accurate and reliable method for the detection of wall perforation during the excimer-laser micro-drilling of glass ampoules and vials. The method is based on the detection of shock waves generated in the air during the drilling process using a laser-beam deflection probe. An analysis of the detected optodynamic signals gives important information about the progress of the drilling process, and we take this as the basis for the presented online process-monitoring method. We show that a significant change in the signal's amplitude is observed when the wall of a liquid-filled ampoule is perforated and the exit process point is in contact with the liquid, and that this signal change can serve as an indicator of wall perforation. We have verified this optodynamic method by examining the processed holes using optical and electron microscopy as well as with a non-destructive gas-leakage test method. The described method was employed for the production of test ampoules used for the adjustment of a high-voltage leak-detection device in a pharmaceutical production line. Holes with a diameter of less than 10 µm were produced in the walls of 0.5 mm thick glass ampoules using a XeCl excimer laser.

  12. Study of ebullition inside a rectangular inclinable channel, of large hydraulic diameter; Etude de l`ebullition dans un canal rectangulaire, inclinable, de grand diametre hydraulique

    Energy Technology Data Exchange (ETDEWEB)

    Nehme, H

    1997-02-18

    This work is performed in the framework of the investigation of-Severe Accidents of Water Cooled Nuclear Power Plants (PWR). A concept of molten core recovery is based on a retention in the lower head of the reactor vessel or in core-catchers which are externally cooled by water, Critical heat flux must be avoided in this external natural convection two-phase flow. The SULTAN experiment has been launched in order to investigate two-phase flow characteristics at experiment is described. Tests are performed under forced convection conditions for extended analytical investigation of the flow characteristics. They are mainly aimed to measure pressure drops, onset of critical heat flux (CHF), temperature and void fraction profiles in the flow. These results are describe and analyzed in a second part. The flow reveals to be very different from the classical flow in narrow channels. The difference is mainly due to 2-D effects and internal flow re-circulations. The limit of validity of 1-D analytical description of the flow is tested. This approach is improved by the proposal of a new correlation for the prediction of net vapor generation point and for the calculation of the mean density along the subcooled part of the flow. New CHF correlations are proposed. CHF is shown to be the same order of magnitude as these measured on the ULPU facility in UCSB and at the MIT. However 1-D approach has limitations at high qualities for large and inclined channels. A better description must be linked to the use of multi-dimensional numerical two-phase flow codes. (author) 87 refs.

  13. Interpreting stem diameter changes

    Science.gov (United States)

    Hölttä, T.; Sevanto, S.; Nikinmaa, E.

    2009-12-01

    Detecting phloem transport in stem diameter changes Teemu Hölttä1, Sanna Sevanto2, Eero Nikinmaa1 1Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland 2Department of Physics, P.O. Box 48, FIN-00014 University of Helsinki, Finland Introduction The volume of living cells and xylem conduits vary according to pressures they are subjected to. Our proposition is that the behavior of the inner bark diameter variation which cannot be explained by changes in xylem water status arise from changes in the osmotic concentration of the phloem and cambial growth. Materials and methods Simultaneous xylem and stem diameter measurements were conducted between June 28th to October 4th 2006 in Southern Finland on a 47-year old, 15 meter tall, Scots pine tree (DBH 15 cm) at heights of 1.5 and 10 meters. The difference between the measured inner bark diameter and the inner bark diameter predicted from xylem diameter change with a simple model (assuming there was no change in the osmotic concentration of the phloem) is hypothesized to give the changes in the osmotic concentration of the inner bark. The simple model calculates the radial water exchange between the xylem and phloem driven by the water potential changes in the xylem. Results and Discussion The major signal in the inner bark diameter was the transpiration rate as assumed, but also a signal arising from the change in the osmotic concentration (Fig 1a). The predicted osmotic concentration of the phloem typically increased during the afternoon due to the loading of photosynthesized sugars to the phloem. Inner bark osmotic concentration followed the photosynthesis rate with a 3 and 4 hour time-lag at the top and base, respectively (Fig 1b). The connection between photosynthesis and the predicted change in phloem osmotic concentration was stronger in the upper part of the tree compared to lower part. The changes in the predicted osmotic concentration were not similar every day, indicating that

  14. Large Diameter Class Larixprincipis-rupprechtii Target Tree Timber Management Technology%华北落叶松大径级材目标树经营技术研究

    Institute of Scientific and Technical Information of China (English)

    支乾坤

    2013-01-01

    Larixprincipis-rupprechtii is the preferred species for base construction,but the larch target tree cultiva-tion cycle is longer exists,slow,market risk and other characteristics. How to cultivate high-quality large-diame-ter timber forest level,to achieve the target tree timber large diameter class sustainable development,and explore scientific and rational management technology has become an important issue we need to solve This paper intro-duced the technology to cultivate large diameter timber and provided suggestions for the existing problems.%  如何培育出优质的大径级材林木,实现大径级材目标树的可持续发展,需要探索科学合理的经营技术。该文主要阐述了培育大径级材林木的技术措施,并针对存在的问题提出发展建议。

  15. 大管径TiO2纳米管的制备及其光解水性能研究∗%Fabrication and photoelectrochemical water splitting performance of large diameter TiO2 nanotube

    Institute of Scientific and Technical Information of China (English)

    李温超; 仲小敏; 杨春艳; 马卫华

    2015-01-01

    Anodization of Ti and the preparation of TiO2 nanotubes with small diameter (20-300 nm)have been reported for many times,however,the fabrication of TiO2 nanotubes with large diameter was still a challenge. In order to fabricate TiO2 nanotube with large diameter,the influence of water content contained in electrolyte on the diameter of TiO2 nanotubes has been investigated in detail.The results show that nanotube diameter in-creases significantly with the increase of water content (from 8% to 12 vol%).However,when the water con-tent increases to 1 3 vol%,the self-ordered nanotubes cannot be obtained by anodization.Further increasing the water content to 20vol%,the compact titanium oxide film can be obtained.Besides,the investigation of voltage affect on the diameter of TiO2 nanotube was carried out in ethylene glycol electrolyte containing 0.3wt% NH4 F and 12vol% H2 O.The results indicate that the largest diameter (about 600 nm)can be obtained at a voltage of 170 V,which has never been reported in the literature.The measurements of photoelectrochemical (PEC)water splitting of the TiO2 nanotubes show that the increase of the nanotubes’diameter was beneficial to their PEC water splitting performance.%采用阳极氧化法制备小管径(20~300 nm)的TiO2纳米管已经有很多报道,但大管径的 TiO2纳米管的制备还是一个挑战.为制备大管径的 TiO2纳米管,研究了高水含量的电解液对纳米管管径的影响.结果表明,纳米管的管径随水含量的增加而增加(8%~12%(体积分数)),而水含量增加到13%(体积分数)时,无法得到规则的纳米管,进一步增加水含量到20%(体积分数),只能得到致密的 TiO2薄膜.此外,在含有0.3%(质量分数)NH4 F 和12%(体积分数)H 2 O 的乙二醇电解液中,研究了不同氧化电压对纳米管管径的影响.结果表明,在170 V 氧化电压下制备的TiO2纳米管的管径可达到600 nm.纳米管的光解水性能测试结果表

  16. Analysis of Efficiency of Drilling of Large-Diameter Wells With a Profiled Wing Bit / Badania Efektywności Wiercenia Studni Wielkośrednicowych Świdrem Skrawającym z Profilowanymi Skrzydłami

    Science.gov (United States)

    Macuda, Jan

    2012-11-01

    In Poland all lignite mines are dewatered with the use of large-diameter wells. Drilling of such wells is inefficient owing to the presence of loose Quaternary and Tertiary material and considerable dewatering of rock mass within the open pit area. Difficult geological conditions significantly elongate the time in which large-diameter dewatering wells are drilled, and various drilling complications and break-downs related to the caving may occur. Obtaining higher drilling rates in large-diameter wells can be achieved only when new cutter bits designs are worked out and rock drillability tests performed for optimum mechanical parameters of drilling technology. Those tests were performed for a bit ø 1.16 m in separated macroscopically homogeneous layers of similar drillability. Depending on the designed thickness of the drilled layer, there were determined measurement sections from 0.2 to 1.0 m long, and each of the sections was drilled at constant rotary speed and weight on bit values. Prior to drillability tests, accounting for the technical characteristic of the rig and strength of the string and the cutter bit, there were established limitations for mechanical parameters of drilling technology: P ∈ (Pmin; Pmax) n ∈ (nmin; nmax) where: Pmin; Pmax - lowest and highest values of weight on bit, nmin; nmax - lowest and highest values of rotary speed of bit, For finding the dependence of the rate of penetration on weight on bit and rotary speed of bit various regression models have been analyzed. The most satisfactory results were obtained for the exponential model illustrating the influence of weight on bit and rotary speed of bit on drilling rate. The regression coefficients and statistical parameters prove the good fit of the model to measurement data, presented in tables 4-6. The average drilling rate for a cutter bit with profiled wings has been described with the form: Vśr= Z ·Pa· nb where: Vśr- average drilling rate, Z - drillability coefficient, P

  17. Prevalence of Failure due to Adverse Reaction to Metal Debris in Modern, Medium and Large Diameter Metal-on-Metal Hip Replacements--The Effect of Novel Screening Methods: Systematic Review and Metaregression Analysis.

    Directory of Open Access Journals (Sweden)

    Aleksi Reito

    Full Text Available Metal-on-metal (MoM hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0, targeted blood metal ion measurement and/or cross-sectional imaging (level 1, metal ion measurement without imaging (level 2, metal ion measurement with targeted imaging (level 3 and comprehensive screening (both metal ions and imaging for all; level 4. 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR, and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13% and the highest with level 4 screening (pooled prevalace 9.49%. Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening

  18. Small diameter carbon nanopipettes

    Science.gov (United States)

    Singhal, Riju; Bhattacharyya, Sayan; Orynbayeva, Zulfiya; Vitol, Elina; Friedman, Gary; Gogotsi, Yury

    2010-01-01

    Nanoscale multifunctional carbon probes facilitate cellular studies due to their small size, which makes it possible to interrogate organelles within living cells in a minimally invasive fashion. However, connecting nanotubes to macroscopic devices and constructing an integrated system for the purpose of fluid and electrical signal transfer is challenging, as is often the case with nanoscale components. We describe a non-catalytic chemical vapor deposition based method for batch fabrication of integrated multifunctional carbon nanopipettes (CNPs) with tip diameters much smaller (10-30 nm) than previously reported (200 nm and above) and approaching those observed for multiwalled carbon nanotubes. This eliminates the need for complicated attachment/assembly of nanotubes into nanofluidic devices. Variable tip geometries and structures were obtained by controlled deposition of carbon inside and outside quartz pipettes. We have shown that the capillary length and gas flow rate have a marked effect on the carbon deposition. This gives us a flexible protocol, useful for growing carbon layers of different thicknesses at selective locations on a glass pipette to yield a large variety of cellular probes in bulk quantities. The CNPs possess an open channel for fluid transfer with the carbon deposited inside at 875 °C behaving like an amorphous semiconductor. Vacuum annealing of the CNP tips at temperatures up to 2000 °C yields graphitic carbon structures with an increase in conductivity of two orders of magnitude. Penetration of the integrated carbon nanoprobes into cells was shown to produce minimal Ca2+ signals, fast recovery of basal Ca2+ levels and no adverse activation of the cellular metabolism during interrogation times as long as 0.5-1 h.

  19. 大直径PLA长丝对3D打印构件力学性能的影响%Effect of Large-Diameter PLA Filament on MechanicalProperties of 3D Printing Component

    Institute of Scientific and Technical Information of China (English)

    权利军; 李丹丹; 赵勇; 祝成炎

    2017-01-01

    熔融沉积型3D打印机通过累积叠加大直径长丝形成构件,鉴于聚乳酸长丝在熔融沉积型3D打印机上的大量使用,本文重点研究了大直径聚乳酸长丝的直径、排列方式、排列密度对3D打印构件力学性能的影响.结果表明:聚乳酸长丝排列越紧密,所打印出构件的拉伸断裂强度越好;同等情况下,聚乳酸长丝以同心线方式排列的构件其拉伸断裂强度最好;当填充密度小于100%时,由0.4 mm聚乳酸长丝构成的3D打印构件机械性能更好.%FDM(fused deposition modeling) 3D printer forms the component through accumulating large-diameter filaments.In view of the extensive use of polylactic acid filaments in FDM 3D printer, the effects of diameter, arrangement and arrangement density of large-diameter polylactic acid filaments on the mechanical properties of 3D printing component were mainly studied in this paper.The experimental results demonstrate that the tensile failure strength of the polylactic acid filaments is better when the filaments are arranged closely;under the same conditions, the component with the arrangement mode of concentric line has the best tensile failure strength.When the packing density is less than 100%, the mechanical property of the component printed by the 0.4mm polylactic acid filament is better than that of the component printed by 0.2 mm polylactic acid filament.

  20. Fabrication of a micro through-hole array by gas-blowing a PDMS-treated polyamide screen for a flexible drag-reducing skin-like device

    Science.gov (United States)

    Li, Yong; Zhou, Kai; Zhao, Xiang; Kong, Quancun

    2017-01-01

    We propose a method for fabricating a flexible skin-like device for generating and trapping micro bubbles with the aim of reducing underwater drag. This low-cost, efficient, high-pressure gas-blow method is used to fabricate a micro through-hole array in a flexible polydimethylsiloxane (PDMS) gel-based skin. The key parameters in the gas-blowing method are investigated, such as the viscosity of PDMS and the blowing pressure in order to optimize the quality of through-hole layer. Deviation of the linear dimensions of the obtained micro holes was less than 4.5%. In addition, multiphase computational fluid dynamics models were built to analyze the drag-reduction performance of bell-shaped holes made by this method. Compared with cylindrical through holes produced by molding, the drag-reduction effect of bell-shaped holes increased as much as 34%.

  1. 大直径筒仓仓顶房滑模托带施工方案%Construction scheme of sliding-mode girdle of the warehouse-top house of large diameter silo

    Institute of Scientific and Technical Information of China (English)

    张继忠; 胡孝平

    2012-01-01

    Taking the large diameter silo engineering of the harbor in Hebei province as an example, this paper introduces the construction scheme of sliding-mode girdle of the warehouse-top house of large diameter silo, respectively expounds the determination of relevant parameters, machine selection, installation technology, quality check:, and technological measures and so on. Comparing to conventional construction scheme, the construction scheme of sliding-mode girdle can speed up the schedule and save cost.%以河北省某港口大直径筒仓工程为例,介绍了大直径筒仓仓顶房滑模托带施工方案,分别阐述了相关参数的确定,机具选择,安装工艺,质量检查及技术措施等内容,指出相对于常规施工方案,滑模托带施工方案能加快进度,节约成本。

  2. Construction technique of large-diameter silo center ring radiation derrick platform hydraulic slipform%大直径筒仓中心井架环式平台滑模施工技术

    Institute of Scientific and Technical Information of China (English)

    秦永强

    2011-01-01

    In this paper, Xishan coal and electricity group Zhenchengdi mine coal storage silo projects for instance, describes the construction technique of large-diameter silo center ring radiation derrick platform hydraulic slipform. For large-diameter silo engineering characteristics of the existing sliding construction process has been improved to not only meet the operating requirements silo slipform construction, but also to solve the warehouse roof structure construction problems.%以西山煤电集团镇城底矿储煤筒仓工程为例,介绍了大直径筒仓中心井架环式辐射操作平台液压滑模施工技术。针对大直径筒仓工程特点,对现有滑模施工工艺进行了改进,使其既满足筒仓滑模施工操作要求,又解决了仓顶结构施工难题。

  3. 大直径气举反循环成套钻具的研制%Development of Complete Set of Large Diameter Air-lift Reverse Circulation Drilling Tool

    Institute of Scientific and Technical Information of China (English)

    袁志坚

    2014-01-01

    The paper introduces a complete set of large diameter air-lift reverse circulation drilling tool about its develop-ment background, design principle, structure dimensions and main technical parameters.This set of drilling tool, designed by interflush, has the advantages of great intensity and convenient connection, and the section area of tubes for ventilation, mud transfortation and mud recharge are fully considered, it can meet the needs of air-lift reverse circulation drilling for large diameter engineering well.%介绍了大直径气举反循环成套钻具的研制背景、设计原则、结构尺寸和主要技术参数。该套钻具不仅强度大,连接便捷,而且充分考虑了通气、通泥浆、泥浆补给三大通道面积等因素,采用内平设计。经生产试验,完全能满足大直径工程井气举反循环钻进的需要。

  4. Magnetoelastic Relationships for Large Diameter Terfenol

    Science.gov (United States)

    2007-11-02

    measuring these constants. 14. SUBJECT TERMS 15. NUMBER OF PAGES Magnetostriction 9 piezomagnetic matrix 16. PRICECODE piezomagnetic constants 17... Introduction The origins of this position paper lie in discussions about the proper form of the compliance matrix and its inverse, the modulus matrix...oriented in the sample plane. Magnetically the magnetostriction constants are not isotropic, in fact, All, >> 1100, which makes the piezomagnetic d

  5. 暗挖导洞内大直径桩施工关键技术研究%Study on key construction technology of casting large-diameter pile in tunnel's drift

    Institute of Scientific and Technical Information of China (English)

    韩竹青; 张宏; 胡宏彪; 程松; 卞正涛; 王生

    2015-01-01

    针对北京地铁15号线新建奥林匹克公园站顺行密贴下穿大屯路隧道的施工技术难点,对传统泵吸反循环钻孔灌注桩施工设备进行改进,使其满足导洞内复杂环境下桩基施工的要求,并对施工工艺进行优化,保证施工安全和成桩质量。桩基施工完成后,通过自平衡法静载试验得到单桩竖向抗压承载力特征值,采用超声波透射法和低应变反射波法对大直径桩桩身完整性进行检测。试验和检测结果均表明,大直径桩均为Ⅰ类桩,桩身完整性良好,实测的单桩竖向抗压承载力特征值均满足设计要求。说明暗挖导洞内大直径桩成套施工技术能够满足成桩质量和效率的要求,保证工程的施工安全。%According to the construction technology difficulty of Olympic Park Station in Beijing Subway Line 15 underneath passing the Datun Road tunnel,the traditional construction equipment system of bored piles with the pump suction reverse circulation method was improved to meet the pile foundation construction requirements under the complex conditions in a drift and the construction technology was optimized to ensure the construction safety and the high quality of the completed piles. After completing the pile foundation construction,the characteristic values of the single pile vertical bearing capacity are obtained by self-balanced static load tests and the integrity of large-diameter pile are tested by using ultrasonic transmission method and low strain reflected wave method. T he test and inspection results showed that large-diameter piles are Ⅰ class and have good integrity,the measured characteristic values of the single pile vertical bearing capacity can meet design requirements,which means the improved construction technology of large-diameter pile in underground excavation drift could meet the needs of the construction quality,efficiency and safety.

  6. Development and Application Status of Non Drilling Type Bridge Plug with Large Internal Diameter%免钻型大通径桥塞研制与应用现状

    Institute of Scientific and Technical Information of China (English)

    李鹏飞; 刘旭辉; 王杰

    2016-01-01

    Staged fracturing of plug-and-perforate is the main technical mean for shale gas develop-ment at home and abroad.In order to ensure the smooth flow of oil and gas in later stage, we needto drill bridge plug using coiled tubing milling tool.There are problems such as take longer,high cost,and easy to stick.Developing non drilling type bridge plug with large internal diameter to re-place composite plug can deal with the problems.The domestic and foreign development and ap-plication status of large internal diameter plug and introducing the structure,principle,technical features,specifications and performance parameters and field application are investigating.The main problems and development trend analyzed and suggestions on developing large internal diam-eter plug are given.%桥塞-射孔联作分段压裂是目前国内外进行页岩气开发所使用的主要技术。在该工艺的施工后期,为了保障油气畅通,需要利用连续油管磨铣工具钻除桥塞,存在耗时较长、成本较高、容易卡钻等问题。研制出免钻型大通径桥塞代替复合桥塞,可以解决这些问题。调研了国内外大通径桥塞的研制与应用现状,介绍了结构、工作原理、技术特点、规格性能参数及现场应用情况。分析了存在的主要问题及发展趋势。给出了大通径桥塞研制的建议。

  7. 基于AHP法的大口径PCCP管道断丝安全风险管理%Large diameter PCCP pipeline broken wires safety risk management based on APH method

    Institute of Scientific and Technical Information of China (English)

    骆建军; 姚宣德

    2016-01-01

    Effectively evaluating the safety on the structure of large diameter PCCP pipeline broken wires and taking effective measures to repair are the ways to reduce the safety risk of broken wires during South to North Water Diversion Proj ect large diameter PCCP pipeline operation.Based on the method of analytic hierarchy process,the hierarchy analysis mathematical evaluation model is established.The possible factors of the influences of various of South to North Water Diversion Proj ect of underground large diameter PCCP pipe broken wires are scored by experts.At the same time,the PCCP pipeline safety failure j udgment criterion and the j udgment standard are established through the numerical simulation.The quantification of safety risk assessment of large diameter PCCP pipe is realized.A specific PCCP North South Pipeline engineering safety running and risk management software is developed. With real-time monitoring automation technology and the risk management system of Web-GIS ,the software can perform real-time acquisition of the monitoring data,data file of electronic management and dynamic assessment and early warming of safety risk.%如何有效地对大口径PCCP管道断丝后管道结构的安全进行合理地评价,以便采取积极有效的维修措施,是减少南水北调大口径 PCCP管道运营期间断丝安全风险的有效途径。提出利用层次分析方法(AHP)建立PCCP管道安全风险层次分析数学评价模型,对影响南水北调地下大口径PCCP管道断丝的各种可能因素进行专家打分,同时,通过数值模拟计算,建立 PCCP管道安全失效的判断准则及判断标准,实现大口径PCCP管道安全风险评价的定量化。在此基础上,开发出一款专门针对南水北调中线PCCP管道工程安全运行风险实时监测的管理软件。该软件系统采用自动化实时监测技术和基于 Web-GIS的风险管理系统。该系统能完成监测数据的实时采集、数据

  8. Rebar modularization design and fabrication technique research for large diameter long drilling pile%大直径超长钻孔灌注桩桩笼的钢筋模块化设计及加工工艺

    Institute of Scientific and Technical Information of China (English)

    陈国平

    2013-01-01

    “钢筋模块化”理念在大直径超长钻孔灌注桩的施工过程中得到了成功的运用,本文通过钢筋模块化设计和施工工艺的描述,由实践证明了钢筋笼采用模块化制作不仅质量高,生产速度快,集中的工厂化生产更能有效地降低施工成本。%Briefing:"Rebar modularization”concept are sucessfully used for large diameter long drilling pile construction.The article prove the high quality and fast production speed with the description of the modularization design and fabrication.The industrialization method can bring down the cost of the construction.

  9. 大直径金属-金属全髋关节置换的早期疗效%Short-term outcome of metal-on-metal total hip arthroplasty with large diameter head

    Institute of Scientific and Technical Information of China (English)

    袁东堂; 左文山; 刘开样; 戴志唐; 徐用亿

    2011-01-01

    BACKGROUND: Dislocation after total hip replacement is still one of the mam complications of traditional metal-on-polyethylenetotal hip replacement. Melal-on-metal lolai hip arthroplasty with large diameter head has a good stability, suitable for young andactive patients with higher requirement of movement.OBJECTIVE: To evaluate the short-term therapeutic effect of total hip arthroplasty with metal-on-metal bearings and largediameter head hip prosthesis.METHODS: A retrospective analysis was done in 48 patients (54 hips) with advanced stage hip disease treated by primary totalhip arthroplasty with metal-on-metal bearings and large diameter head hip prosthesis. The mean diameter of femoral headprosthesis was 44 mm (38 to 48 mm). The postoperative short-term effect was evaluated with Harris scores and X-ray plain.RESULTS AND CONCLUSION: Ail patients received the foliow-up of 18 to 36 months. The mean Harris hip score was 93.6 (91 to96) at the last follow-up. Trie mean range of hip motion was 232.6° (182° to 257°) at the last follow-up. There were no infection, nohip and thigh pain, no vessel and nerve complications, no dislocation. Posl-opretive X-ray plain revealed fine position of theprostheses without any loosening. Short-term results show that large diameter metal-on-metal total hip arthroplasty hasadvantages of lower wearing, large range of motion and few dislocations.%背景:髋关节置换后脱位仍然是传统的金属对聚乙烯全髋关节置换的主要并发症之一,大直径金属对金属的全髋关节置换后具有良好的稳定性,适合年轻、活动要求高的患者.目的:验证大直径金属-金属全髋关节置换治疗终末期髋关节疾病的早期疗效.方法:回顾性分析48例(54髋)初次大直径金属-金属全髋关节置换后的早期临床疗效.假体股骨头直径平均为44 mm(38-48 mm),采用Harris评分和X射线检查评估早期疗效.结果与结论:所有患者都获得18~36个月

  10. Application of large diameter Wear-resisting pipe in wash-box and gangue chute%大直径耐磨管在跳汰机中煤、矸石溜槽中的应用

    Institute of Scientific and Technical Information of China (English)

    郭小林

    2015-01-01

    This paper introduces the reformation process and results of the wash-box and gangue chute in coal preparation plant of sized coal system jig coal in Yangquan coal industry (Group) NO.1 mine from the rectangular section welded by steel plates to large diameter wear-resisting pipe.%该文介绍了阳泉煤业(集团)一矿选煤厂粒级煤系统跳汰机中煤、矸石溜槽由钢板焊接的矩形断面溜槽改为大直径耐磨管溜槽的过程及改造后的效果。

  11. TIG Auto-Welding Technology on Heavy Wall Thickness Large Diameter and Narrow Gap Welded Pipe%厚壁大直径管窄间隙TIG自动焊技术

    Institute of Scientific and Technical Information of China (English)

    张相福

    2011-01-01

    Aiming at the disadvantages of the TIG-SMAW for heavy wall thickness and large diameter welded pipe, the narrow gap impulse TIG auto-welding technology was developed; it solved some design difficulties in TIG welding, such as penetration in weld sidewall, bevel design and etc. Through research on penetration technology in weld sidewall for narrow gap heavy wall thickness welding, the bevel combination for TIG welding was developed. It designed specified range welding parameters for heavy wall thickness welded pipe with the said bevel, and its process was validated in welding practice; it successfully solved process difficulties of narrow gap TIG auto-welding with heavy wall thickness and large diameter, and obtained excellent effect%针对厚壁大径管氩电联合焊的缺点,开发了窄间隙脉冲TIG自动焊工艺,解决了厚壁大直径管窄间隙TIG焊中焊缝侧壁熔透、坡口设计等难点,通过研究厚壁管窄间隙焊接焊缝侧壁熔透技术,开发厚壁大直径管窄间隙TIG焊组合坡口,设计焊接该种坡口厚壁管的特定范围的焊接工艺参数,并在焊接实例中进一步验证了该工艺技术的可靠性,成功解决了厚壁大直径管窄间隙TIG自动焊的工艺难点,并取得了良好的生产效果.

  12. Mechanized Matched Rapid Construction of Large Diameter Mine Full Depth Freezing Shaft%大直径全深冻结立井机械化配套快速施工

    Institute of Scientific and Technical Information of China (English)

    刘彦杰; 张贵民; 范聚朝; 曹忠常

    2014-01-01

    A net diameter of a mine auxiliary shaft in Gaojiabu Mine was 8.5m.The mine auxiliary shaft was sunk with a full depth freezing method ,the freezing depth of the auxiliary shaft was 850m ,the sinking depth of the mine shaft was 841.5m and the mine shaft liner was a double reinforced concrete shaft liner.A mechanized operation line of the mine shaft rapid construction was consisted with a Ⅵtype shaft sinking headframe ,large hoist ,large kibbles ,large formworks ,hydraulic umbrella drilling rig ,central rotating type hydraulic grabs ,bottom hook type automatic refuse tipping device ,dump trucks and other advanced equipments.A short sectional excavation and lining combined operation was applied to the mine shaft sinking with medium and deep borehole blasting ,floor cleaning with small type excavator ,concrete transportation with large diameter material transportation pipeline and other advanced technology.A month shaft completed within a continuous five month of shaft excavation and outer shaft lining was over 100m obtained ,an average month shaft completed was 120m and the expe-riences would be provided to the safety and rapid construction of the mine full depth freezing shaft.%高家堡煤矿副立井净直径8.5m ,采用全深冻结法凿井,冻结深度850m ,凿井深度841.5m ,双层钢筋混凝土井壁。井筒采用Ⅵ型凿井井架、大提升机、大吊桶、大模板、液压伞形钻架、中心回转式液压抓岩机、座钩式自动翻矸装置、自卸汽车等先进设备组成的立井快速施工机械化作业线,中深孔爆破、小型挖掘机清底、大直径输料管输送混凝土等先进技术,短段掘砌,混合作业,取得了连续5个月掘砌外壁月成井超百米,平均月成井120 m的好成绩,为全深冻结立井安全快速施工提供了经验。

  13. Development of Large Diameter Jetting PDC Reaming Tool of CBM Wells%煤层气井射流式 PDC 大直径扩孔工具研制

    Institute of Scientific and Technical Information of China (English)

    李壮

    2014-01-01

    Based on the principle and performance of reamer both at home and abroad,according to the characteristics of coal petrography,a large diameter jetting PDC reaming tool (RT152-500) which is applied to cavitation completion of CBM wells completion is developed.Based on high pressure jet fluid mechanics mechanism,high and low pressure flow channel and nozzle diameter are optimal designed by using CFD software.It is an effective pressure compensation and energy storage device,and driven by hydraulic power in the whole process.The synergistic effect of high pressure jet broken and mechanical broken can be achieved.Larger than 500 mm diameter hole is formation after expanding when used 142mm small size tool.The structure of the tool is simple, the operation is safe and reliable and the cavitation ability is strong.%在深入调研国内外扩孔器原理和性能的基础上,研制出适应煤层气完井造穴用的 RT152-500型射流式 PDC 大直径扩孔工具。依据流体力学的高压喷射作用机理,利用 CFD 计算软件对工具内高、低压流道及喷嘴直径进行优化设计,形成有效的压降补偿蓄能装置,全程水力驱动,达到高压喷射破岩和机械破岩的协同作用,实现φ142 mm 小通径工具进入,扩孔后直径大于φ500 mm 的大直径洞穴。该工具结构简单,作业安全可靠,造穴能力强。

  14. Unit distances and diameters in Euclidean spaces

    CERN Document Server

    Swanepoel, Konrad J

    2007-01-01

    We show that the maximum number of unit distances or of diameters in a set of n points in d-dimensional Euclidean space is attained only by specific types of Lenz constructions, for all d >= 4 and n sufficiently large, depending on d. As a corollary we determine the exact maximum number of unit distances for all even d >= 6, and the exact maximum number of diameters for all d >= 4, for all $n$ sufficiently large, depending on d.

  15. Large Diameter Freeze Shaft Single Wellbore Grouting Plugging Technology Research%大直径冻结井筒单层井壁注浆堵水技术研究

    Institute of Scientific and Technical Information of China (English)

    陈德明; 段安新

    2014-01-01

    To study the freezing of large diameter single wellbore wall grouting technology for large amount of leakage problems wellbore door grams celebrate mine shaft began to thaw vice combining technical features wellbore wall hydrogeological conditions and parameters of the wellbore after the walls ,curtains and wall impermeable microcracks take phased ,focused carried grouting .The results show that:the amount of leakage from the wellbore 233 m3/h reduced to 4.5 m3/h,reaching the amount of wellbore leakage specifications .%为研究大直径冻结井筒单层井壁注浆堵水技术,针对门克庆矿副立井开始解冻后井筒漏水量较大的问题,结合井筒的技术特征、水文地质情况和井壁参数,对井筒壁后、隔水帷幕及井壁微裂纹采取分阶段、分重点进行注浆堵水。结果表明:井筒漏水量由233 m3/h降低为4.5 m3/h,达到井筒漏水量规范要求。

  16. 大管径垂直管道内高压汽液混合流动的数值研究%Numerical Study of High Pressure Vapor-Liquid Flow in Large-Diameter Vertical Pipes

    Institute of Scientific and Technical Information of China (English)

    黄娜; 周云龙; 高聚

    2015-01-01

    A numerical simulation based on the volume of fluid (VOF) method was used to study vapor–liquid flow in a 190 mm vertical tube under high pressure, and the flow pattern maps of the two-phase convection flow were investigated under pressure of 5.07, 10.13 and 17.23 MPa, respectively. The results of flow under high pressure were compared with that of normal pressure. The results show that the flow pattern maps under high pressure in large-diameter vertical pipes are not consistent with the Hewitt and Roberts flow pattern maps. No wispy annular is presented under high pressure in large-diameter vertical pipes, and the bubbly zone and churn zone are enlarged. The slug zone becomes particularly small with little change happened to the annular zone. The simulation results show that the interfacial wave amplitude of the vapor-liquid churn flow decreases with the increase of pressure in large-diameter vertical pipes, and the interface stability is enhanced at the same time. The pipe central area has the highest velocity, which fluctuates at the boundary area and reduces to zero on the pipe wall. Moreover, the disorder degree of the oscillatory velocity field near the pipe wall decreases under high pressure. Mechanisms were analyzed following the simulation results dicussed.%采用流体体积模型(VOF)对高压环境下190 mm大管径垂直管内水蒸汽-水混合流动进行数值研究。数值计算得到了5.07,10.13与17.23 MPa高压下大管径垂直管内汽液流型分布图及搅混流态的相分布图和速度场分布,并与常压下的计算结果进行对比,以研究压力环境带来的影响。数值结果表明,高压环境下大管径垂直管内的流型图与Hewitt和Roberts流型图的吻合度较差。高压环境下大管径垂直管内没有出现雾状流;泡状流和搅混流的发生区域扩大;弹状流的发生区域被压缩得很小;环状流的变化最小。随着压力的增大,大管径垂直管内汽液搅混流中

  17. Double diameter boring tool

    Science.gov (United States)

    Ashbaugh, Fred N.; Murry, Kenneth R.

    1988-12-27

    A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation. The method includes the step of inserting the boring tool into the boring head, adjusting the distance between the tool centerline and the tool axis of rotation as described above and boring the two concentric holes.

  18. Effect Observation of Large Diameter Silicon Tube Combined with Talcum Powder for Primary Spontaneous Pneumothorax%粗管径硅胶管结合滑石粉治疗自发性气胸的效果观察

    Institute of Scientific and Technical Information of China (English)

    王乃杰

    2014-01-01

    Objective:To explore the clinical effect of large diameter silicon tube combined with talcum powder for primary spontaneous pneumothorax. Method:80 cases were divided into two groups according to random number table method,each group had 40 cases,the observation group were used large diameter silicon tube and the control group were used central venous catheter patients,then the related time of the clinical effect and complications were compared with the two groups. Result:In the observation group,puncture time was shorter than the control group(P<0.05),the patients symptoms improved time was faster than the control group(P<0.05),the catheter indwelling time was shorter than the control group (P<0.05),secondary pneumothorax and tube pulmonary edema ratio were lower than the control group(P<0.05),chest pain ratio,conduit clogging and recurrence within 3 years were lower than the control group. Conclusion:The thick silica relative compare with the central venous catheter diameter tube for primary spontaneous pneumothorax is more precise and it has fewer complications,so it is a safe and reliable treatment method.%目的:探讨粗管径硅胶管结合滑石粉治疗自发性气胸的临床效果。方法:将80例患者按随机数字表法分为两组,每组各40例,其中观察组使用粗管径硅胶管行胸腔闭式引流,对照组则使用中心静脉导管进行治疗。比较两组患者治疗的相关时间,并统计并发症情况。结果:观察组穿刺成功时间短于对照组(P<0.05),患者症状改善时间快于对照组(P<0.05),且导管留置时间短于对照组(P<0.05),出现继发性气胸、脱管及肺水肿的比率均显著低于对照组(P<0.05);观察组出现胸痛、导管堵塞及3年内复发的比率显著低于对照组(P<0.05)。结论:粗硅胶管结合滑石粉治疗及预防自发性气胸相对于细管径的中心静脉导管,其治疗效果更确切,并发症少,是一种安全可靠的治疗方法。

  19. Flow field analysis and improvement on the large diameter butterfly valve in the supersonic wind tunnel%超音速风洞大口径蝶阀流场分析及改进

    Institute of Scientific and Technical Information of China (English)

    张耀平; 马东平; 丁天伟; 杨洋

    2011-01-01

    The configuration of the large diameter butterfly valve in the supersonic wind tunnel is introduced.Flow fields of the butterfly valve with different structure discs and different valve opening are analyzed by COSMOSFloWorks.The flow field is improved by adding cover for disc and punching on the cover.The worst service condition is avoided by adding bypass valves to butterfly valves,and so the failure rate is reduced and the life is prolonged.%介绍了超音速风洞大口径蝶阀的配置形式。运用COSMOSFloWorks软件分析了不同结构蝶板及蝶阀不同开度情况下的流场情况。通过在蝶板上增加蒙皮以及在蒙皮上开孔的方式改善了蝶阀的流场,蝶阀配置旁路阀的方式改善了蝶阀的使用工况,从而降低了蝶阀的故障率,延长了蝶阀的使用寿命。

  20. Metal ion levels in large-diameter total hip and resurfacing hip arthroplasty-Preliminary results of a prospective five year study after two years of follow-up

    Directory of Open Access Journals (Sweden)

    Maurer-Ertl W

    2012-04-01

    Full Text Available Abstract Background Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern. Methods The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively. Results The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p  Discussion In order to clarify the biologic effects of ion dissemination and to identify risks concerning long-term toxicity of metals, the exposure should be monitored carefully. Therefore, long-term studies have to be done to determine adverse effects of Co and Cr following metal-on-metal hip replacement.

  1. 一種大直徑薄壁輸水管道敷設的計算方法%A Calculation Method of Laying Thin-walled Water Pipelines with Large Diameter

    Institute of Scientific and Technical Information of China (English)

    孟强; 吴云云

    2014-01-01

    大陆输水成为东南沿海诸岛屿供水主要途径,大直径薄壁跨海输水管道敷设成为主要技术难题。采用奇异摄动法,求含小参数微分方程的解析解,并给出了一种简洁的非线性方程组计算方法。以“舟山市大陆引水二期工程”为例,通过数值计算与现场陆上试验比对,验证了非线性方程计算方法的合理性。%Continental water has become a main way of water supply to southeast coastal islands .How to laying thin-walled cross-sea water pipelines with large diameter becomes a major technical problem .Using the singular perturbation method and obtaining the analytical solution of the differential equation containing small parameter , this paper gives a simple calculation method of nonlinear equations .Taking” Zhoushan continent diversion project II” as an example and comparing the numerical calculation with onshore test ,the rationality of the calculation method of nonlinear equations is verified in this paper .

  2. FE modeling of a complete warm-bending process for optimal design of heating stages for the forming of large-diameter thin-walled Ti–6Al–4V tubes

    Directory of Open Access Journals (Sweden)

    Tao Zhijun

    2017-01-01

    Full Text Available Warm rotary draw bending (WRDB of large-diameter thin-walled (LDTW Ti–6Al–4V tube is a multi-nonlinear thermo-mechanical coupled process. Due to the high-cost, energy-wasting and long-term, the traditional physical experiments based on “trial and error” are no longer suitable for the WRBD process. Considering the non-uniform local heating and multi-tool constraints, a thermal–mechanical coupled 3D FE model of complete WRDB process for LDTW Ti–6Al–4V tube is established on ABAQUS as heating-bending-unloading three-stage. The FE models could predict the overall temperature distribution, describe thermo-mechanical bending deformation considering a modified Johnson–Cook model, and simulate the heating-bending-springback-cooling process. On that basis, the temperature distributions on both tube and dies under various heating schemes are compared, and the optimal heating scheme is determined on the basis of forming quality and efficiency. Combined with the experiments of WRDB, the optimal heating scheme and the established FE models are verified. In conclusion, the FE simulation provides a replacement of physical experiment and a convenient method of deformation prediction for WRDB of LDTW Ti–6Al–4V tube.

  3. Research on Design,Manufacturing and Inspection of Large-diameter Multi-wave Nuclear Expansion Joint%大直径多波核用金属膨胀节设计、制造与检验

    Institute of Scientific and Technical Information of China (English)

    卢江; 高利霞; 冯吉建; 周景蓉; 张倩; 黄雪

    2015-01-01

    研究某核电厂高温气冷堆金属堆内构件用金属波纹膨胀节,由核电站工程建设中连接管路系统的柔性补偿装置,补偿由于热胀冷缩等原因引起的金属堆内构件、陶瓷堆内构件和反应堆压力容器之间尺寸变化。介绍了大直径多波核用金属波纹膨胀节的设计、制造与检验关键点,为核电产品同类金属波纹膨胀节制作提供经验。%The effect of high temperature of a nuclear power plant expansion joint for corrugated metal re-actor internals gas cooled reactor was studied,which is a flexible compensation device for connecting with the pipeline system engineering in nuclear power plant construction and compensating the size variation between the cause of expansion and contraction of the reactor internals such as metal,ceramic reactor in-ternals and reactor pressure vessel.The keys of design,manufacturing and inspection of large-diameter multi-wave nuclear expansion joint were introduced.It provided inspection section for the production of similar products of metal bellows expansion of nuclear power.

  4. Flow Field Analysis and Structure Optimization of Large Diameter Butterfly Valve Based on the CFX%基于 CFX 的大口径蝶阀的流场分析及结构优化

    Institute of Scientific and Technical Information of China (English)

    何庆中; 王渝皓; 王佳; 蒲虎; 厉明玉

    2016-01-01

    青海尕曲水电站大口径三偏心主控蝶阀在小开度工况下振动强烈,本文利用其二维图纸建立了蝶阀在不同开度下的流道模型,并利用 CFX 软件对其流场进行了数值模拟。数值分析结果表明:5%~30%开度区间内蝶阀下游的涡街现象强烈。同时,对蝶板结构进行了优化,优化前后分析结果对比表明:改进后蝶阀流场的涡街效应明显减弱,有效预防涡街共振的发生,为以后大型蝶阀的设计提供了参考。%The large diameter butterfly valve used in Qinghai Naqu hydropower station was subjected to strong vibration when the opening was small.This paper established the flow model of butterfly valve for different opening degrees with the 2D drawings and simulated the flow field by using CFX software.The results of numerical analysis show that the vortex are the most strong in the range of 5% to 30%.Meanwhile,an improved structure was given and the results of numerical analysis show that the vortex effect decreased significantly for the new one.This new structure can effectively prevent the vortex resonance and give an example for the new design of a large butterfly valve.

  5. FY1995 study of perfect-closed ULSI manufacturing system for future large-diameter wafer processing; 1995 nendo jisedai daikokei wafer taio kanzen closed ULSI seizo sochi system no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The purpose of this study is to develop advanced processing technologies to fabricate ultra-large-scale-integrated circuit on large-diameter wafers with high-precision and no-fluctuations at low temperatures. We develop the plasma process technologies to generate high-density uniform plasma with high-controllability to realize very precise manufacturing and low-temperature processing, and technologies for the high-performance process apparatus in which wafer surface is never exposed to atmosphere and therefore ultraclean wafer surface in atomic level are always maintained and molecules and ions react on the wafer surface in perfect accordance with reaction theories. We have developed a plasma process equipment using RLSA (Radial Line Slot Antenna) for formations of high-quality thin films. As a result, high-density uniform plasma has been successfully produced. The kinetic energy of bombarding ions onto the semiconductor substrate surface can be reduced to 7eV in this microwave plasma. Therefore high-quality thin films without any damages can be successfully formed. Next, we have developed magnetron plasma equipment with dipole-ring magnet for deep sub-micron etching. It was revealed that deviation of the plasma due to E x B drifts of electrons was perfectly improved by applying RF to an upper ring electrode. It was also revealed that to realize a closed manufacturing system, in which the wafers are transported in an ultra clean N{sub 2} environment and the wafer surface are never exposed to atmosphere, is essential for the deep sub-micron semiconductor manufacturing with high-reliability. Additionally, very fine-structure and bonding state of Si (100) surface which are terminated by hydrogen or fluorine, chorine was made clear by calculations using quantum chemistry under the three-dimensional periodic boundary condition. (NEDO)

  6. Effect of process parameters on growth rate and diameter of nano-porous alumina templates

    Indian Academy of Sciences (India)

    P Chowdhury; K Raghuvaran; M Krishnan; Harish C Barshilia; K S Rajam

    2011-06-01

    Anodic aluminium oxide (AAO) template with hexagonal shaped nano-pores with high aspect ratio was fabricated by two-step anodization processes from high purity aluminium foil. It was observed that pore dimensions were affected by anodizing voltage, electrolyte temperature and the duration of anodization time. The vertical growth rate of the pores (10–250 nm/min) was found to vary exponentially with anodizing voltage; however, it exhibits linear increment with the electrolyte temperature. The measured pore diameter (50–130 nm) shows a linear variation with anodizing voltage. The bottom barrier oxide layer was etched out by pore widening treatment to obtain through holes.

  7. Resisting Moment Behavior of Large Diameter and Shallow Buried Bucket Foundation for Offshore Wind Turbine%海上风电大直径宽浅式筒型基础抗弯特性分析

    Institute of Scientific and Technical Information of China (English)

    刘润; 陈广思; 刘禹臣; 徐余

    2013-01-01

      风机属于高耸结构物,承受巨大的弯矩是海上风电基础区别于其他常见结构基础的重要特征。大直径宽浅式筒型基础是适应海上风电特征荷载作用的新型基础型式。筒型基础的直径、入土深度、顶盖及侧壁厚度是控制其抗弯能力的重要技术参数。结合某海上风电工程实例,采用数值分析方法,系统研究了不同尺寸特征参数对筒型基础传递及抵抗弯矩荷载的影响,揭示了弯矩荷载作用下宽浅式筒型基础的失效模式及基础转动点位置;研究了地基承载力设计中等效均质算法的合理性。研究表明:基础抗弯承载能力随筒型基础的直径及入土深度的增加而显著增长;在弯矩荷载作用下,筒周围土体出现贯通的弧形破坏面而在基础下方土体中存在曲边三角形的稳定区;对于实际工程中的上软下硬成层土地基,经等效均质化后,将导致计算得到的基础抗弯极限承载力明显偏高。%The wind turbine belongs to high-rise structure. The foundation of wind turbine must bear huge moment, which is different from other common structure foundations. The large diameter and shallow buried bucket foundation is a new foundation type which meets the requirement of the characteristic load of offshore wind turbine. The impor-tant technological parameters of bucket foundation for resisting moment are diameter, embedded depth, upper wall and lateral thickness. An offshore wind power project is taken as an example, and the impacts of the characteristic pa-rameters of different size on bucket foundation transferring and resisting moment load are systematically studied by numerical simulation. The failure mechanisms and rotating point position of bucket foundation are revealed under moment load. The rationality of equivalent homogeneous algorithm is studied in designing the bearing capacity of the foundation. Research shows that the bearing capacity of

  8. 应用固定砂石总体积法配制大粒径自密实混凝土%Preparation of self-compacting concrete with large diameter aggregate by fixed total volume of sand and gravel

    Institute of Scientific and Technical Information of China (English)

    危加阳; 罗竹容

    2014-01-01

    The method of fixed volume of sand and gravel is commonly used in mixture proportion design of self-compacting concrete. In order to return to the natural properties of aggregate, the method of fixed total volume of sand and gravel that is dif-ferent from the traditional concept is proposed, i. e. , in the mixture proportion design of self-compacting concrete, we should ensure it completely enwrapped, separated and suspended by cementing material. Moreover, this method is also applied in the preparation of self-compacting concrete with the maximum size of 31. 5 mm of coarse aggregate. The practices show that the self-compacting concrete still has good stability of anti-segregation and demonstrates that the preparation of self-compacting con-crete with large diameter aggregate by fixed total volume of sand and gravel is feasible.%固定砂石体积法是设计自密实混凝土配合比的常用方法。为回归骨料的天然属性,提出了有别于传统概念的固定砂石总体积法,即在配制自密实混凝土时,按胶凝材料浆包裹、分隔、悬浮总骨料为目标进行配比计算。同时,在工程实际中,利用该方法尝试将最大粒径为31.5 mm且具有较好抗离析稳定性的粗骨料用于自密实混凝土配制。实践证明,利用固定砂石总体积法配制较大粒径骨料自密实混凝土是可行的。

  9. 大直径SMW工法设计与施工关键技术分析%Analysis of the Design and Construction Techniques for Soil Mixing Wall (SMW) with Large Diameter

    Institute of Scientific and Technical Information of China (English)

    张亚君

    2013-01-01

    深基坑支护设计,不仅要保证基坑内的正常作业,而且要防止基坑及坑外土体的移动,确保基坑附近建筑物、道路、管线等的正常使用.因此,深基坑围护结构的安全性显得尤为重要.在众多围护方法中,SMW工法(型钢水泥土搅拌墙)以其适用性强、围护成本低、施工周期短而倍受关注.文章结合工程实践,对大直径SMW工法在软土地基深基坑支护中的支护结构设计及施工要点及难点进行了分析和探讨.%It is a key point for the security of deep foundation pit enclosure structure in the design of deep foundation pit support which guarantees the normal construction of foundation pit and prevents from soil mass movement inside and outside the pit in order to keep the normality of buildings,roads and pipelines nearby.Special attention was given to the soil mixing wall featuring good applicability,low construction cost and short construction period.Based on the construction practice,some discussions of the key techniques in the design and construction were made regarding the application of soil mixing wall with a large diameter to deep foundation pit in soft soil.

  10. A two-center comparative study of plastic and lumen-apposing large diameter self-expandable metallic stents in endoscopic ultrasound-guided drainage of pancreatic fluid collections

    Science.gov (United States)

    Ang, Tiing Leong; Kongkam, Pradermchai; Kwek, Andrew Boon Eu; Orkoonsawat, Piyachai; Rerknimitr, Rungsun; Fock, Kwong Ming

    2016-01-01

    Background and Objectives: Endoscopic ultrasound-guided drainage of walled-off pancreatic fluid collections (PFCs) (pseudocyst [PC]; walled-off necrosis [WON]) utilizes double pigtail plastic stents (PS) and the newer large diameter fully covered self-expandable stents (FCSEMS) customized for PFC drainage. This study examined the impact of type of stent on clinical outcomes and costs. Patients and Methods: Retrospective two-center study. Outcome variables were technical and clinical success, need for repeat procedures, need for direct endoscopic necrosectomy (DEN), and procedure-related costs. Results: A total of 49 (PC: 31, WON: 18) patients were analyzed. Initially, PS was used in 37 and FCSEMS in 12. Repeat transmural drainage was required in 14 (PS: 13 [9 treated with PS, 4 treated with FCSEMS]; FCSEMS: 1 [treated with PS]) due to stent migration (PS: 3; FCSEMS: 1) or inadequate drainage (PS: 10). Technical success was 100%. Initial clinical success was 64.9% (25/38) for PS versus 91.7% (11/12) for FCSEMS (P = 0.074). With repeat transmural stenting, final clinical success was achieved in 94.6% and 100%, respectively (P = 0.411). Compared to FCSEMS, PS was associated with greater need for repeat drainage (34.2% vs. 6.3%, P = 0.032). The need for and frequency of DEN was similar between both groups, but PS required more frequent balloon dilatation. PS was significantly cheaper for noninfected PC. Costs were similar for infected PC and WON. Conclusion: PS was associated with a higher need for a second drainage procedure to achieve clinical success. The use of FCSEMS did not increase procedural costs for infected PC and WON.

  11. The Energy Diameter Effect

    Energy Technology Data Exchange (ETDEWEB)

    Vitello, P; Garza, R; Hernandez, A; Souers, P C

    2007-07-10

    We explore various relations for the detonation energy and velocity as they relate to the inverse radius of the cylinder. The detonation rate-inverse slope relation seen in reactive flow models can be used to derive the familiar Eyring equation. Generalized inverse radii can be shown to fit large quantities of cylinder results. A rough relation between detonation energy and detonation velocity is found from collected JWL values. Cylinder test data for ammonium nitrate mixes down to 6.35 mm radii are presented, and a size energy effect is shown to exist in the Cylinder test data. The relation that detonation energy is roughly proportional to the square of the detonation velocity is shown by data and calculation.

  12. The Energy Diameter Effect

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P; Vitello, P; Garza, R; Hernandez, A

    2007-04-20

    Various relations for the detonation energy and velocity as they relate to the inverse radius of the cylinder are explored. The detonation rate-inverse slope relation seen in reactive flow models can be used to derive the familiar Eyring equation. Generalized inverse radii can be shown to fit large quantities of cylinder and sphere results. A rough relation between detonation energy and detonation velocity is found from collected JWL values. Cylinder test data for ammonium nitrate mixes down to 6.35 mm radii are presented, and a size energy effect is shown to exist in the Cylinder test data. The relation that detonation energy is roughly proportional to the square of the detonation velocity is shown by data and calculation.

  13. Research on Environmental Adaptability of Large Diameter Infrared Zoom Projection System%大口径红外变焦投影系统环境适应性研究

    Institute of Scientific and Technical Information of China (English)

    韩旭; 焦海丽

    2015-01-01

    对大口径变焦投影系统环境适应性进行仿真研究.影响其力学和光学性能因素主要有公路运输和环境温度,首先对整体结构进行约束模态分析,计算出系统的基频为79.781Hz,远大于二级道路运输的要求50Hz×120%,在运输过程中不会产生共振现象.利用同一模型对其温度适应性进行了研究,通过光机热集成分析方法,找到影响其成像质量的最主要因素为主次镜的曲率变化,在满足系统成像质量的前提下,得到了系统的热控指标约为20±27℃左右,远高于系统的正常工作温差,因此系统的设计是合理可行的.%For large diameter zoom projection system study on the simulation environment adaptability, highway trans-portation and the environment temperature were the major influencing factors, first, modal analysis was carried out on the structure,the first order of the system frequency is 79.781Hz,greater than 50Hz×120% what is the secondary road transport, in the course of carriage will not produce the phenomenon of resonance and self motivation. Using the same model on the temperature adaptability of research by optical thermal analysis integrated methods, to find the most im-portant factors affecting the image quality is the changes in the curvature of the Cassette primary and secondary mirror, under the premise of meeting the image quality, the system thermal control indicator is about 20 ± 27℃, far above the normal operating temperature difference,so the design of the system is reasonable and feasible.

  14. 敏感海域大直径钢管沉桩施工环保措施研究*%Research on Environmental Protection Measures in Construction of Steel Pipe Pile Driving with Large Diameter in Sensitive Sea Areas

    Institute of Scientific and Technical Information of China (English)

    谭昱; 陈儒发; 谭逸波

    2014-01-01

    To weaken the adverse effects of the pile foundation construction for marine engineering on the marine environment, this paper analyzes environmental sensitivity in construction of steel pipe pile driving for large-diameter and deep-long pile foundation. The special noise reduction device, that is air curtain generator, which has been designed in the experiment. To study noise reduction effect of the bubble curtain in the process of pile driving;simultaneously, comparative analysis the strength of the impact on the environment of the different pile driving formation. The results shows that attenuation of the noise peak sound pressure up to 24% to 74% when the air curtain generator is turned on. The noise peak sound pressure generated by impact pile driving is significantly greater than by vibratory pile driving. The noise of impact pile driving has a higher energy distribution in a certain frequency range.%为减弱海洋工程桩基础施工对海域环境造成的不良影响,开展大直径深长桩基础钢管沉桩施工的环境敏感性研究,本试验设计特制的减噪装置为气幕发生器,以研究沉桩过程中气泡帷幕的减噪效果;同时,对比分析了不同沉桩形成对环境影响的强弱。结果表明:钢管沉桩时开启气幕发生器,噪声峰值声压衰减量可达24%~74%;撞击沉桩产生的噪声峰值声压明显大于振动沉桩所产生的噪声峰值声压,撞击沉桩噪声在一定的频带范围内有较高的能量分布。

  15. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole

    Directory of Open Access Journals (Sweden)

    Byung-Chul Jeong

    2015-01-01

    Full Text Available Recently a submicron particle of biphasic calcium phosphate ceramic (BCP with through-hole (donut-shaped BCP (d-BCP was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  16. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole.

    Science.gov (United States)

    Jeong, Byung-Chul; Choi, Hyuck; Hur, Sung-Woong; Kim, Jung-Woo; Oh, Sin-Hye; Kim, Hyun-Seung; Song, Soo-Chang; Lee, Keun-Bae; Park, Kwang-Bum; Koh, Jeong-Tae

    2015-01-01

    Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  17. Template-free synthesis of Nd{sub 0.1}Bi{sub 0.9}FeO{sub 3} nanotubes with large inner diameter and wasp-waisted hysteresis loop

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Guo, F.; Wang, X. [College of Physics and Material Science, Tianjin Normal University, Tianjin 300074 (China); Wang, S. Y., E-mail: shouyu.wang@yahoo.com, E-mail: wfliu@tju.edu.cn [College of Physics and Material Science, Tianjin Normal University, Tianjin 300074 (China); Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Xu, X. L.; Liu, W. F., E-mail: shouyu.wang@yahoo.com, E-mail: wfliu@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Gao, J. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2015-08-10

    One-dimensional (1D) nanotubes of Nd{sub 0.1}Bi{sub 0.9}FeO{sub 3} (NBFO) with an inner diameter of ∼50 nm were synthesized via sol-gel based electrospinning without template assistant. The phases, morphologies, crystalline structures, and magnetic properties of these 1D nanostructures were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and SQUID, respectively. It was found that the calcination condition plays a crucial role in determining the morphologies and the magnetic properties. Interestingly, these 1D NBFO nanotubes exhibit wasp-waisted magnetic hysteresis with a lower coercivity and larger saturation magnetization, which were prevalent in natural rocks and artificial composite materials. The origin of these wasp-waisted hysteresis loops was discussed.

  18. Reduced artery diameters in Klinefelter syndrome.

    Science.gov (United States)

    Foresta, C; Caretta, N; Palego, P; Ferlin, A; Zuccarello, D; Lenzi, A; Selice, R

    2012-10-01

    Various epidemiological studies in relatively large cohorts of patients with Klinefelter syndrome (KS) described the increased morbidity and mortality in these subjects. Our aim was to study the structure and function of arteries in different districts to investigate in these subjects possible alterations. A total of 92 patients having non-mosaic KS, diagnosed in Centre for Human Reproduction Pathology at the University of Padova, and 50 age-matched healthy male controls were studied. Klinefelter syndrome subjects and controls evaluation included complete medical history, physical examination, measurement of concentrations of the reproductive hormones, lipidic and glycidic metabolism, AR function and sensitivity, ultrasound examinations (diameters, carotid intima-media thickness and brachial flow-mediated dilation) of brachial, common carotid and common femoral artery and abdominal aorta. Klinefelter syndrome patients showed significantly reduced artery diameters in all districts evaluated. On the contrary no statistically significant difference was found in cIMT and brachial FMD values between KS patients and controls. Furthermore, we found no statistically significant correlation of artery diameters with reproductive hormones, metabolic parameters, anthropometric measures and weighted CAG repeats. To our knowledge, this is the first study finding a reduced artery diameter in several districts in KS patients compared with that of normal male subjects and overlapping to that of female subjects. We have not an explanation for this phenomenon, even if a possible involvement of genes controlling the development of vascular system might be hypothesized, and further research is required to verify this hypothesis.

  19. 大直径微型钢管桩桩基托换技术在地铁施工中的应用%Application of Large-diameter Micro Steel Pipe Pile Underpinning Technology in Construction of Metro Works

    Institute of Scientific and Technical Information of China (English)

    谢永盛

    2012-01-01

    广州地铁二、八号线延长线洛溪站—南洲站盾构区间从彩虹花园密集桩群中通过,大量桩基侵入盾构掘进区域,需对彩虹花园进行加固处理,但加固施工空间狭小。为了解决彩虹花园加固处理难题,采用350 mm大直径微型钢管桩进行桩基托换,盾构到达原桩位置时采取停机截桩方案进行加固处理。加固过程中建筑物沉降稳定,未出现任何裂缝,结构完好,达到预期加固效果,可供相似工程进行参考。%Luoxi stationNanzhou station shield tunneling section on the extended section of No. 2 and No. 8 line of Guangzhou Metro passes through the pile group of Caihong Garden. Many piles intrude into the clearance of the shield bored tunnel, therefore Caihong Garden should be reinforced. Furthermore, the operation space for the reinforcement is small. Micro steel pipe piles with 350 mm diameter are adopted to underpin the pile foundation. When the shield arrives at the position of the existing piles, the piles are cut and reinforcement is made. During the reinforcement, the settle ment of the buildings is stable and expected reinforcement effect is achieved.

  20. Research on Technology for Rapid Construction Method of Double Deck in Large Diameter Shield Tunnel%盾构隧道内部双层结构快速化施工方法技术研究

    Institute of Scientific and Technical Information of China (English)

    黄俊; 马明; 李勇; 赵光; 张忠宇; 赵爽

    2013-01-01

    With the increasing of shield tunnel diameter, double decked lane structure is widely used. Traditionally the lane structure is mainly constructed by cast-in-place formwork method. Because the space in the tunnel is limited, the construction organization is difficult, and the construction speed is slow. Based on the survey on the rapid construction methods, prefabrication design technology is proposed to increase the construction speed of the internal structure of the shield tunnel in this paper. Combining with the construction design of double decked lane in the Nanjing Wei San River-crossing shield tunnel engineering, structural concept designs of upper carriageway of "precast slab+ beam slab node post-cast" and "precast slab+ support" are proposed for the first time. The design parameters, such as the width of the precast slab, the connection method of precast slab, are analyzed, too. The construction organization analysis shows that using the prefabrication design technology, the construction speed and the flexibility of the construction organization are better than using the cast-in-place formwork design technology.%随着盾构隧道直径的增加,双层车道结构在大直径盾构隧道设计中得到了广泛的应用.传统盾构隧道内部结构设计采用现浇混凝土结构.由于空间狭小,施工组织困难,施工速度慢.通过对现有隧道快速化施工方法的研究,提出了采用预制化结构设计加快盾构隧道内部结构施工速度的设计技术.结合南京市纬三路过江通道工程盾构隧道双层行车道结构设计,通过对上层车道结构预制化方法的研究,首次提出“预制车道板+梁板节点后浇”和“预制车道板+支座”两类上层行车道预制结构方案,并对预制车道板预制宽度、拼接做法等设计要素进行了对比分析.施工分析表明预制结构速度在施工速度、施工组织灵活性等方面均优于现浇结构施工.

  1. Diameters of Triton and Pluto

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, D.; Cruikshank, D.P. (Hawaii Univ., Honolulu (USA). Inst. for Astronomy); Brown, R.H. (Hawaii Univ., Honolulu (USA). Dept. of Physics and Astronomy; Hawaii Univ., Honolulu (USA). Hawaii Inst. of Geophysics)

    1982-12-02

    Upper limits are reported to the thermal IR emission from Triton, the major satellite of Neptune, and Pluto, the outermost planet, that permit significant upper limits to be set on their diameters and also demonstrate that both are high albedo objects. These results exclude the possibility that Triton is the largest planetary satellite and are consistent with the small size of Pluto deduced from other data.

  2. Femtosecond laser ablated durable superhydrophobic PTFE films with micro-through-holes for oil/water separation: Separating oil from water and corrosive solutions

    Science.gov (United States)

    Yong, Jiale; Fang, Yao; Chen, Feng; Huo, Jinglan; Yang, Qing; Bian, Hao; Du, Guangqing; Hou, Xun

    2016-12-01

    Separating the mixture of water and oil by the superhydrophobic porous materials has attracted increasing research interests; however, the surface microstructures and chemical composition of those materials are easily destroyed in a harsh environment, resulting in materials losing the superhydrophobicity as well as the oil/water separation function. In this paper, a kind of rough microstructures was formed on polytetrafluoroethylene (PTFE) sheet by femtosecond laser treatment. The rough surfaces showed durable superhydrophobicity and ultralow water adhesion even after storing in various harsh environment for a long time, including strong acid, strong alkali, and high temperature. A micro-through-holes array was further generated on the rough superhydrophobic PTFE film by a subsequent mechanical drilling process. The resultant sample was successfully applied in the field of oil/water separation due to the inverse superhydrophobicity and superoleophilicity. The designed separation system is also very efficient to separate the mixtures of oil and corrosive acid/alkali solutions, exhibiting the strong potential for practical application.

  3. Fully Mechanized Matching Construction Technology of Large Diameter Deep Mine Shaft%大直径深立井综合机械化配套施工技术

    Institute of Scientific and Technical Information of China (English)

    张贵民; 范聚朝

    2014-01-01

    门克庆煤矿主井井筒施工中,采用Ⅵ型凿井井架,3台大能力单钩提升机配5/6 m3吊桶提升,8臂伞形钻架配8台YGZ型凿岩机钻眼,中深孔爆破,2台 HZ-6型中心回转式抓岩机装岩,1台CX-75型防爆挖掘机辅助清底、刷帮,4.2m高的M JY型液压整体金属模板砌筑井壁,正规循环作业,平均月进尺91m ,最高月进尺126m ,工程质量优良,安全无事故,实现了安全、优质、快速施工。%In a mine main shaft construction of Menkeqing Mine ,a Ⅵ mode mine shaft sinking head-frame and three sets of large capacity single hook hoists with 5/6m3 kibbles were applied to the mine hoisting ,a eight boom umbrella drill rig with eight YGZ rock drills was applied to the borehole drilling for the medium depth blasting boreholes ,two HZ-6 central rotary rock garbs were applied to the rock loading ,a CX-75 flameproof excavator was applied to the floor cleaning and sidewall reaming and a 4.2m height MJY hydraulic integrated steel templet was applied to the concrete lining.With a normal circulated operation ,a mine average shaft construction rate per month was 91m and a max month rate was 126m.The project quality was excellent and no safety accident was occurred. Thus a safety ,excel-lent quality and rapid construction of the mine shaft was realized.

  4. The truth about laser fiber diameters.

    Science.gov (United States)

    Kronenberg, Peter; Traxer, Olivier

    2014-12-01

    To measure the various diameters of laser fibers from various manufacturers and compare them with the advertised diameter. Fourteen different unused laser fibers from 6 leading manufacturers with advertised diameters of 200, 270, 272, 273, 365, and 400 μm were measured by light microscopy. The outer diameter (including the fiber coating, cladding, and core), cladding diameter (including the cladding and the fiber core), and core diameter were measured. Industry representatives of the manufacturers were interviewed about the diameter of their fibers. For all fibers, the outer and cladding diameters differed significantly from the advertised diameter (P cladding, and core diameters of fibers with equivalent advertised diameters differed by up to 180, 100, and 78 μm, respectively. Some 200-μm fibers had larger outer diameters than the 270- to 273-μm fibers. All packaging material and all laser fibers lacked clear and precise fiber diameter information labels. Of 12 representatives interviewed, 8, 3, and 1 considered the advertised diameter to be the outer, the cladding, and the core diameter, respectively. Representatives within the same company frequently gave different answers. This study suggests that, at present, there is a lack of uniformity between laser fiber manufacturers, and most of the information conveyed to urologists regarding laser fiber diameter may be incorrect. Because fibers larger than the advertised laser fibers are known to influence key interventional parameters, this misinformation can have surgical repercussions. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Experimental strain measurements on large diameter mitered pipe joints

    Energy Technology Data Exchange (ETDEWEB)

    Feier, Ioan I.; Leis, Brian N.; Zhu, Xian-Kui [Battelle Memorial Institute, Columbus, OH (United States); Stonesifer, Randall B. [Computational Mechanics Inc., Julian, PA (United States); Stavrakas, John S. [National Grid, Waltham, MA (United States); Eletto, Daniel D. [National Grid, Hicksville, NY (United States)

    2010-07-01

    Nowadays, small directional changes in a piping system are achieved by using cold field bent sections however, in the past, miter joints were used and so some pipelines still have such joints. The aim of this study was to determine the stress amplification due to miters in gas transmission pipelines. Experiments were carried out on X42 pipeline steel miter joints, 3 were taken from the Clove Lakes segment of the National grid system and 3 were manufactured for the test, all miter angles were between 0 and 8 degrees of total pipeline direction change; strain gauges were used to measure hoop and axial strains. Results showed that the stress increase due to miter joints increases linearly with the miter angle; in addition it was found that miters on the studied pipeline did not compromise its integrity. This study provided a good understanding of miter induced stress but results are limited to pipe with r/t values of 30.

  6. Steady state modeling of large diameter crystal growth using baffles

    Science.gov (United States)

    Sahai, Vivek; Williamson, John; Overfelt, Tony

    1991-01-01

    Buoyancy driven flow in the crystal melt is one of the leading causes of segregation. Natural convection arises from the presence of thermal and/or solutal gradients in the melt and it is not possible to completely eliminate the convection even in the low gravity environment of space. This paper reports the results of computational modeling research that is being done in preparation for space-based experiments. The commercial finite element code FIDAP was used to simulate the steady convection of a gallium-doped germanium alloy in a Bridgman-Stockbarger furnace. In particular, the study examines the convection-suppressing benefits of inserting cylindrical baffles in the molten region to act as viscous dampers. These thin baffles are assumed to be inert and noncontaminating. The results from this study show the manner in which the streamlines, velocities, and temperature fields at various gravity levels are affected by the presence of baffles. The effects of changing both the number and position of the baffles are examined and the advantages and disadvantages of using baffles are considered.

  7. Insensitive detonator apparatus for initiating large failure diameter explosives

    Science.gov (United States)

    Perry, III, William Leroy

    2015-07-28

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  8. Preparation of Large-Diameter GaAs Crystals.

    Science.gov (United States)

    1981-09-18

    pinch-off voltage in directly implanted FET structures. It ing attention oer the past decade. Monolithically in- is probable that the high and...reproducible 2. t:F. M Swiggard. S. H. tcc and F. W. Von Iatchelder, Ins. implant profiles showing excellent agreement with LSS Phys. Conf. Ser. Ni. 336

  9. 基于FLAC3D的超长大直径钢管桩竖向承载特性模拟%Simulation of vertical bearing features for large-diameter and super-long steel pipe pile based on FLAC3D

    Institute of Scientific and Technical Information of China (English)

    张明远; 黎生南; 彭文韬; 宋华珠

    2011-01-01

    More and more large-diameter and super-long steel pipe piles are applied to engineering in recent years. But so far , few people have focused on studing their bearing characteristics. Computational theory of ordinary piles is referenced in the foundation design. Vertical bearing and settlement features are simulated for large-diameter and super-long steel pipe piles based on the fast Lagrangian analysis of continua in three dimensions (FLAC3D). Then comparison between simulation results and the results of vertical static load bearing capacity test is conducted and they are complemented and verified each other. The consistent results demonstrate that the method of using the finite difference procedure in this paper to preliminarily simulate the vertical load-bearing characteristics and settlement characteristics of large-diameter and super-long steel pipe pile is feasible. The study shows that the large-diameter and super-long steel pipe pile is a typical end-bearing friction pile. The pile lateral friction resistance changes intricately with depth, which is closely related to the soil characteristics. And the transferring speed of pile axial force depends on the action of pile lateral friction resistance in the different soil. These conclusions are of significance for the reasonable large-diameter and super-long steel pipe pile foundation designed in engineering applications.%近年来,超长大直径钢管桩在工程中的应用已越来越多,但对其承载特性的研究却很少,设计中仍然参考普通桩的计算理论.本文采用三维连续介质快速拉格朗日法(FLAC3D)对实际工程中一超长大直径开口钢管桩试桩的竖向承载特性及沉降特性进行了数值模拟分析,并将模拟结果与静载荷竖向承载特性试验实测结果进行了对比,两者相互补充和相互验证,取得了比较一致的结果,表明了本文所编制的有限差分程序用以初步模拟分析超长大直径钢管桩承载特性的可行

  10. The Non-Homologous Nature of Solar Diameter Variations

    CERN Document Server

    Sofia, S; Demarque, P; Li, L; Thuillier, G; Sofia, Sabatino; Basu, Sarbani; Demarque, Pierre; Li, Linghuai; Thuillier, Gerard

    2005-01-01

    We show in this paper that the changes of the solar diameter in response to variations of large scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times larger than the variation at a depth of 5 Mm, which is about the level at which f-mode solar oscillations determine diameter variations. This model is supported by observations that indicate larger diameter changes for high degree f-modes than for low degree f-modes, since energy of the former are concentrated at shallower layers than the latter.

  11. Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines

    Directory of Open Access Journals (Sweden)

    Tamar Andelman

    2007-01-01

    Full Text Available A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm nanorods were synthesized from trihexylamine, and large diameter (50–80 nm nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green emission of the photoluminescence (PL spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.

  12. Diameter of common bile duct: what are the predicting factors?

    Directory of Open Access Journals (Sweden)

    Atoosa Adibi

    2007-07-01

    Full Text Available

    BACKGROUND: This was a study to determine the correlation between the common bile duct (CBD diameter and demographic data, fasting, and the history of opium addiction.
    METHODS: This was a cross-sectional study on 375 patients (>16 years old including 219 females and 156 males. They had no evident hepatobiliary or pancreatic disease and underwent abdominopelvic ultrasonography for measurement of their CBD diameter. Ultrasound (US was performed to measure CBD diameter at the porta hepatis (proximal part and behind the head of the pancreas (distal part. Correlation coefficients for the association between CBD diameter and predictive factors were calculated. t-test was applied to compare the means between the groups.
    RESULTS: The mean CBD diameter (1 standard deviation, in proximal and distal parts were 3.64 mm (±1.2 and 3.72 mm (±1.2, respectively. The CBD diameters (proximal and distal were significantly (P<0.05 correlated with age (r = 0.55 and 0.54, respectively, BMI (r = 0.25 and 0.27, respectively and portal vein diameter (r = 0.24 and 0.22, respectively. Distal diameter of CBD was significantly larger in opium addicts (5.66 ± 2.65 in comparison with non addicts (3.68 ± 1.17, P = 0.04.
    CONCLUSIONS: CBD diameter associates with age, BMI, portal vein diameter and opium addiction. CBD dilatation, if it can not be explained by age, opium usage or large BMI, should be evaluated further to rule out obstruction.
    KEY WORDS: Common bile duct, predicting factors, ultrasonography.

  13. Diameter dependence of thermoelectric power of semiconducting carbon nanotubes

    Science.gov (United States)

    Hung, Nguyen T.; Nugraha, Ahmad R. T.; Hasdeo, Eddwi H.; Dresselhaus, Mildred S.; Saito, Riichiro

    2015-10-01

    We calculate the thermoelectric power (or thermopower) of many semiconducting single wall carbon nanotubes (s-SWNTs) within a diameter range 0.5 -1.5 nm by using the Boltzmann transport formalism combined with an extended tight-binding model. We find that the thermopower of s-SWNTs increases as the tube diameter decreases. For some s-SWNTs with diameters less than 0.6 nm , the thermopower can reach a value larger than 2000 μ V /K at room temperature, which is about 6 to 10 times larger than that found in commonly used thermoelectric materials. The large thermopower values may be attributed to the one dimensionality of the nanotubes and to the presence of large band gaps of the small-diameter s-SWNTs. We derive an analytical formula to reproduce the numerical calculation of the thermopower and we find that the thermopower of a given s-SWNT is directly related with its band gap. The formula also explains the shape of the thermopower as a function of tube diameter, which looks similar to the shape of the so-called Kataura plot of the band gap dependence on tube diameter.

  14. EFFECT OF LOADING RATE ON TENSILE PROPERTIES OF FULL-SCALE SPECIMEN OF LARGE-DIAMETER GLASS FIBER REINFORCED POLYMER(GFRP) BAR%加载速率对大直径GFRP筋足尺试件抗拉性能的影响

    Institute of Scientific and Technical Information of China (English)

    李国维; 葛万明; 倪春; 戴剑; 牟春林

    2012-01-01

    The glass fiber reinforced polymer(GFRP) bar is a new reinforcement material composed of glass fiber and resin, and has good application prospects. The GFRP bar has the properties of anisotropy. Its horizontal compressive strength far less than axial tensile strength; and it has remarkable size effect. Therefore, the strength index testing of GFRP is more complex than that of steel. The end anchorage problem of large-diameter full-scale GFRP test specimen is solved by laboratory test. Through the tensile test of full-scale specimen of large-diameter GFRP in the tensile testing machine, the variation laws of the basic mechanical properties of large-diameter glass fiber bar, such as tensile strength, tensile elastic modulus and elongation ratio, are studied under different loading rates. In addition, the failure mechanisms between the GFRP bar and steel bar are compared. The experimental results demonstrate that, with increase of loading rate, the tensile strength and elongation ratio of GFRP bar increase significantly, while the elastic modulus remains roughly constant; the mechanical characteristics and failure modes are determined by the materials' composition and structure.%玻璃纤维增强聚合物(GFRP)筋是一种由玻璃纤维与树脂复合而成的新型加固材料,具有良好的应用前景.GFRP筋为非均质各向异性材料,横向抗压强度远小于轴向抗拉强度,具有显著的尺寸效应,因此,GFRP筋强度指标的测试比钢筋材料更复杂.本文试验解决大直径GFRP筋足尺试件的端部锚固问题.通过在拉力试验机上进行大直径GFRP筋足尺试件的抗拉破坏性试验,研究不同加载速率下大直径GFRP筋的抗拉强度、拉伸弹性模量、延伸率等基本力学指标的变化规律,并对比分析GFRP筋与钢筋的受力破坏机制.试验结果表明,随着加载速率的增大,大直径GFRP筋的抗拉强度、延伸率明显增大,拉伸模量的变化幅度较小,基本保持恒定;并分

  15. Experimental investigation of countercurrent flow limitation (CCFL) in a large-diameter hot-leg geometry: A detailed description of CCFL mechanisms, flow patterns and high-quality HSC imaging of the interfacial structure in a 1/3.9 scale of PWR geometry

    Energy Technology Data Exchange (ETDEWEB)

    Al Issa, S., E-mail: salissa.email@gmail.com; Macian-Juan, R.

    2014-12-15

    Highlights: • Countercurrent flow limitation is experimentally investigated in a large-diameter hot-leg pipe geometry (D{sub in} = 190 mm, ∼1/3.9 scale of a PWR hot-leg). • High-speed and high-quality imaging was implemented to study the interfacial structure and flow patterns during flooding and deflooding. • Two main mechanisms were identified and described in details: bend-CCFL and ADE-CCFL. Four regions were recognized for j{sub water,in}{sup *0.5}=0.085−0.305.. • Experimental curves of the onset of CCFL, and deflooding were discussed. High-quality images provide valuable validation data for CFD. • Form a safety point of view: onset of ADE-CCFL precedes the onset of bend-CCFL and its influence cannot be neglected for j{sub water,in}{sup *0.5}>0.27.. - Abstract: Countercurrent flow limitation (CCFL) is experimentally investigated in large-diameter hot-leg geometry. COLLIDER test facility consists of reactor vessel simulator (RVs), hot-leg pipe, and a steam generator simulator (SGs) and was constructed to be a 1/3.9 scale model of a real PWR geometry. The facility is completely transparent providing excellent conditions for optical observation of the gas/liquid interface. Experiments were performed at atmospheric pressure using air/distilled water as flow mediums. High-quality high speed recording (HSC) was implemented to acquire the air/water interface which provided a unique and detailed look into the interface structure within the entire hot-leg geometry. This allowed a precise and a high-qualitative identification and description of the flow patterns and mechanisms by which the onset of CCFL occurs. A systematic experimental investigation of the onset of CCFL and deflooding was carried out for water inlet velocities in the range J{sub w,in}{sup *0.5}=0.085−0.305,ΔJ{sub w,in}{sup *0.5}=0.01. Air velocity was increased and decreased stepwise to identify the onset of CCFL and deflooding limits precisely. Two onset of CCFL mechanisms were

  16. 7 CFR 51.2850 - Diameter.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Diameter. Diameter means the greatest dimension measured at right angles to a straight line running from...

  17. 7 CFR 51.712 - Diameter.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... § 51.712 Diameter. Diameter means the greatest dimension measured at right angles to a line from stem...

  18. 7 CFR 51.651 - Diameter.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946...) Definitions § 51.651 Diameter. Diameter means the greatest dimension measured at right angles to a line from...

  19. Measuring angular diameters of extended sources

    NARCIS (Netherlands)

    van Hoof, PAM

    2000-01-01

    When measuring diameters of partially resolved sources like planetary nebulae, H II regions or galaxies, often a technique called Gaussian deconvolution is used. This technique yields a Gaussian diameter, which subsequently has to be multiplied by a conversion factor to obtain the true angular

  20. ø219.1/168.3 mm 气举反循环双壁钻具及其在大直径工程井中的应用%ø219.1/168.3 mm Air-lift RC Dual Wall Drilling Tools and Their Use in Large Diameter Drilling

    Institute of Scientific and Technical Information of China (English)

    熊亮; 袁志坚; 白领国; 彭桂湘; 耿建国

    2013-01-01

    Considering the shortcomings such as low efficiency, long construction period, high risk etc.of the commonly used large diameter drilling process which consists of direct circulation drilling and stepped reaming, a219.1/168.3 mm dual-wall, and168.3 mm internal flush drill pipes have been developed with the complete accessories, and successfully used to drilling a 1200 mm diameter , 651.2 m deep gas drainage well.The drilling tool is large in size, has high strength, and is connected with special threads.Field use indicates that the drilling tool has high tensile and torsional strength with good sealing.Compared with conventional drilling processes, the air-lift reverse circulation technique provides good cutting-carrying capacity, and increases the rate of penetrate by 74.3% with the quality borehole.In addition, drilling risk is greatly reduced owing to cleanliness of the borehole.%针对当前国内普遍采用“正循环回转钻进+分级扩孔”方法施工大直径工程井效率低、周期长、工程风险大等不足,研制了饱219.1/168.3 mm气举反循环双壁钻具和饱168.3 mm内平单壁钻具及配套附属器具,并成功应用于某直径1200 mm、深651.2 m的大口径瓦斯抽排井。该套钻具尺寸大,强度高,采用特殊螺纹连接。现场应用表明,钻具抗拉、抗扭强度高,密封性能好,应用气举反循环施工较传统工艺携岩效果好,机械钻速提高74.3%,井身质量优。此外,由于井内干净,钻井风险也得以大幅降低。

  1. Fast connection of large-diameter PE pipes. A new generation of heating coil welding technologies. A technical comparison between the new wedge-shaped joint and the conventional cylindrical foint for PE pipes d 1000 and larger; PE-Grossrohre im Handumdrehen verbinden. Eine neue Generation der Heizwendelschweisstechnik. Ein technischer Vergleich zwischen der neuen Keilmuffe und der herkoemmlichen zylindrischen Muffe fuer PE-Rohre d 1000 und groesser

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Robert [FRIATEC AG, Mannheim (Germany)

    2011-07-01

    Wedge-shape joints are a revolution in large-diameter pipe connection. Fitting is simplified considerably as compared to conventional cylindrical joints. Reproducible high-quality connections are achieved at only a fraction of the time formerly required. Assembly follows clear and simple rules. Anybody who can assemble a flange will be able to cope with the tightening system of the wedge-shaped joint.

  2. 大直径内置光纤光栅玻璃纤维增强聚合物锚杆梁杆黏结试验%BOND BEHAVIOR BETWEEN CONCRETE FRAME BEAM AND LARGE-DIAMETER GLASS FIBER REINFORCED POLYMER(GFRP) ANCHOR ROD WITH BUILT-IN FIBER BRAGG GRATING SENSOR

    Institute of Scientific and Technical Information of China (English)

    李国维; 戴剑; 倪春; 殷建华; 余亮

    2013-01-01

      纤维增强聚合物筋是一种新型复合材料,具有优异的力学性能和耐腐蚀性能,用其替代钢筋用于边坡加固是解决锚杆耐久性问题的途径之一。采用内置光纤光栅的 GFRP 筋制作锚杆结构模型,用空心液压千斤顶施加拉拔荷载,用光栅传感技术监测杆体应变,研究大直径喷砂 GFRP 锚杆在框架梁锚固条件下的受力破坏机制。研究表明,本试验大直径25 mm GFRP 锚杆在拉拔力、平均黏结强度方面均达到相同直径螺纹钢筋锚杆的设计指标,最合理的框架梁厚度为30~40 cm;瞬时荷载循环对 GFRP 锚杆界面黏结状态无明显影响;持续荷载作用下杆体界面的黏结状态会发生蜕化,随时间延续蜕化向深部扩展,荷载越大扩展深度越大,蜕化速度越快;光纤光栅监测技术是发现和观察锚杆界面黏结状态蜕化过程的有效手段。%  Fiber reinforced polymer(FRP) is a new composite material with excellent mechanical properties and corrosion resistance. It is a significant way to solve the durability problem of anchor rod by substituting this polymer for steel bars. Using anchor-rod-structure specimen made from glass fiber reinforced polymer(GFRP) bars with fiber grating installed internally,loaded by hollow hydraulic jack,monitored by grating sensing technology,this paper focuses on the failure mechanism of large-diameter sand-coated GFRP rebar in the frame beams under the condition of anchoring. Research shows that in the experiment,in terms of tensile force and average bond strength,this large-diameter(25 mm) GFRP rebar has reached the design strength of ribbed steel with the same diameter. The most reasonable thickness of frame beam varies from 30 to 40 cm. Transient loading cycles have no obvious influence on GFRP rebar interface-bond state;the degradation of rod body interface-bond state will occur under sustained loads,and it continues to develop and expand to

  3. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    CERN Document Server

    Nugent, C R; Bauer, J; Cutri, R M; Kramer, E A; Grav, T; Masiero, J; Sonnett, S; Wright, E L

    2016-01-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids and 8,885 other asteroids. $84\\%$ of the near-Earth asteroids did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within $ \\pm \\sim20\\%$ and $\\pm\\sim40\\%$, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large ($>100$ m), and have low albedos.

  4. 大直径超长群桩有效桩长问题的有限元参数分析%Parametric finite element analysis of effective pile-length in super-long and large-diameter pile groups

    Institute of Scientific and Technical Information of China (English)

    陈培震; 栾茂田; 罗强

    2012-01-01

    采用大型有限元软件ABAQUS,针对大直径超长群桩的有效桩长进行三维有限元数值分析.采用极限承载力控制法,对竖向荷载下不同布桩形式的大直径超长群桩基础的有效桩长进行研究.结果表明:有效桩长随桩数的增多而增大,随桩距的增大而减小;桩数增多,有效桩长对应的群桩的极限承载力降低,桩距的变化对有效桩长对应的群桩的极限承载力影响不大.%Based on the framework of FEM software ABAUQS, the three-dimensional numerical analysis for effective length of super-long and large-diameter pile groups is provided. For the pile groups of different arrangements under vertical loading, the effective pile-length was analyzed with the method of bearing capacity control. The results show that the effective pile-length increases with pile number while decreases with the space between piles. The corresponding bearing capacity decreases with pile number while the space between piles has little effect on the corresponding bearing capacity.

  5. 1998 Annual Study Report. Standardization of methods for evaluating characteristics of high-strength, large-diameter steel pipes for superhigh-pressure natural gas pipelines; 1998 nendo seika hokokusho. Chokoatsu tennen gas pipeline yo kokyodo daikei kokan no tokusei hoho no hyojunka

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The pipelines for safely transmitting superhigh-pressure natural gas should have excellent characteristics. The steel pipe is required to have a sufficient toughness, more concretely Charpy impact-absorbing energy, to prevent propagating shear fracture characteristic of natural gas pipelines. Recently, the natural gas pipeline is increasingly required to have higher design pressures (15 Mpa or higher) and grade (X80 or higher). In order to develop the techniques for simulating crack propagation in the propagating shear fracture of natural gas pipe lines as part of the programs to cope with these trends, the 1998 efforts were directed to reviewing the research results obtained so far and analysis of the problems to be solved and tasks to be taken, based on which the analytical procedure for gas releasing phenomena during the fracture process was basically developed, the material characteristic data were collected by the laboratory scale toughness tests, and the preliminary tests with rupture disks were conducted to verify the above analytical procedure. These efforts have established the bases for evaluating the characteristics of high-strength, large-diameter steel pipes in the light of safety against fracture, and greatly advanced the program towards the final target of developing the international specification drafts for toughness. (NEDO)

  6. Evaluation of local tensions through finite elements applied to a large diameter pipe subjected to vacuum condition of a petroleum refinery; Avaliacao das tensoes locais atraves de elementos finitos aplicada a uma tubulacao de grande diametro sujeita a condicao de vacuo de uma dada refinaria de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Julio C. Goes; Balbi, Diego J. G. [Promom Engenharia, Rio de Janeiro, RJ (Brazil)

    2012-07-01

    The objective of this paper is to present an evaluation of the results obtained in the study of local stress in wall of large diameter pipe. The case study consists of to analyze a pipeline system with 66 inch, which is responsible for transporting oil, oven to the Tower of vacuum distillation unit in a petroleum refining. The absence of internal pressure leads to a critical with respect to the collapse of the walls of the tube in long sections, without the presence of additional elements increase the rigidity of the geometry. The ASME Section VIII Division 1 advocates the use of additional plates, called stiffeners, which aim to curb the efforts from this condition. Thus, it is necessary structural assessment of critical portions of the system in implementing this solution. Therefore, complementary approaches have been proposed, passing by ASME B31.3, Section VIII Division 1, moreover, a computer simulation of stresses through the finite element method, which the results were analyzed according to criteria of tensions presents in ASME Code Section VIII Division 2. (author)

  7. 大直径球囊扩张治疗80例贲门失弛缓症的中远期疗效评价分析%Large-diameter balloon dilation for the treatment of achalasia of cardia: an analysis of mid-to-long term efficacy in 80 cases

    Institute of Scientific and Technical Information of China (English)

    宋锦文; 印建国; 杨艳; 刘晓红; 王志宏

    2011-01-01

    目的 探讨并总结大直径(40 mm)球囊扩张治疗贲门失弛缓症的方法及中远期疗效.方法 80例患者病程3 ~ 23年.Mellow-Pinkas吞咽困难分级(0 ~ 4级)为:Ⅰ级6例,Ⅱ级60例,Ⅲ级14例;均经钡餐透视(12例行胃镜检查)证实.在2%利多卡因咽部喷雾麻醉下,以球囊间歇(间隔3 ~ 5 min)、逐渐扩张贲门狭窄部至球囊最大径40 mm,重复2 ~ 3次.术后常规预防出血和感染,2 ~ 3 h即可进食较凉流质饮食、3 d内进半流质饮食并逐渐过度为正常进食.术后随访问2 ~ 10年.结果 操作成功率100%,其中1次操作治疗成功96.3%(77/80),2次扩张(3例先经小球囊预扩)成功3.7%(3/80).术后破裂行手术修补1例(1.2%).术后随访平均6.27年,其中大于10年4例,6 ~ 10年44例,3 ~ 5年21例,2年11例,吞咽困难缓解率100%,其中能正常进食90%(72/80),正常进食时偶有轻度梗噎感10.0%(8/80).轻度食管反流占15.0%(12/80).结论 从患者接受程度、疗效及并发症等综合评价,大直径球囊扩张术是目前治疗贲门失弛缓症的最佳方法.具有操作简单、创伤小、费用低且中远期疗效较好的优点,可作为成年人贲门失弛缓症的首选治疗方法.%Objective To discuss the technical points of large diameter (40 mm ) balloon dilation in treating achalasia of cardia, and to assess its mid-to-long term efficacy. Methods A total of 80 patients of achalasia of cardia with a disease course of 3 - 23 years were enrolled in this study. According to Mellow-Pinkas standard of the dysphagia grading (from 0 to IV), the patients were classified into grade I(n= 6). Grade Ⅱ(n = 60) and grade Ⅲ(n = 14). The diagnosis was confirmed by barium meal examination in all patients. Under spraying anesthesia of pharyr.geal portion with 2% lidocaine. The intensified guide wire was inserted, into the stomach through mouth, under fluoroscopy guidance. Ihe ooste-n s balloon v 4-0 mm in diameter / was pushed along Uie

  8. Impact Structures: What Does Crater Diameter Mean?

    Science.gov (United States)

    Turtle, E. P.; Pierazzo, E.; Collins, G. S.; Osinski, G. R.; Melosh, H. J.; Morgan, J. V.; Reimold, W. U.; Spray, J. G.

    2004-03-01

    Crater diameter is an important parameter in energy scaling and impact simulations. However, disparate types of data make the use of consistent metrics difficult. We suggest a consistent terminology and discuss it in the context of several examples.

  9. Defining a Minimum End Mill Diameter

    Directory of Open Access Journals (Sweden)

    A. E. Dreval'

    2015-01-01

    Full Text Available Industrial observations show that the standard mill designs in many cases do not provide a complete diversity of manufacturing operations, and a lot of enterprises are forced to design and manufacture special (original designs of tools. The information search has revealed a lack of end mill diameter calculations in publications. There is a proposal to calculate the end mill diameter either by empirical formulas [2, 3], or by selection from the tables [4].To estimate a minimum diameter of the end mill to perform the specified manufacturing operations based on the mill body strength the formulas are obtained. The initial data for calculation are the flow sheet of milling operation and properties of processed and tool materials. The end mill is regarded, as a cantilevered beam of the circular cross section having Dс diameter (mill core diameter with overhang Lв from rigid fixing and loaded by the maximum bending force and torque.In deriving the formulas were used the following well-reasoned assumptions based on the analysed sizes of the structural elements of the standard mills: a diameter of mill core is linearly dependent on the mill diameter and the overhang; the 4τ 2 to σ 2 4τ2 ratio is constant and equal to 0.065 for contour milling and 0.17 for slot milling.The formulas for calculating the minimum diameter are as follows:  3 обр в 1 121 1.1  K S L L D m C z    for contour milling;  3 обр в 1 207 1.1  K S L L D m C z    for slot milling.Obtained dependences that allow defining a minimum diameter of the end mill in terms of ensuring its strength can be used to design mills for contour milling with radius transition sections, holes of different diameters in the body parts and other cases when for processing a singlemill is preferable.Using the proposed dependencies for calculating a feed of the maximum tolerable strength is reasonable in designing the mills for slots.Assumptions used in deriving

  10. Shaft Diameter Measurement Using Structured Light Vision

    OpenAIRE

    2015-01-01

    A method for measuring shaft diameters is presented using structured light vision measurement. After calibrating a model of the structured light measurement, a virtual plane is established perpendicular to the measured shaft axis and the image of the light stripe on the shaft is projected to the virtual plane. On the virtual plane, the center of the measured shaft is determined by fitting the projected image under the geometrical constraints of the light stripe, and the shaft diameter is meas...

  11. Appendiceal diameter: CT versus sonographic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Orscheln, Emily S. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati, OH (United States); Trout, Andrew T. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2016-03-15

    Ultrasound and CT are the dominant imaging modalities for assessment of suspected pediatric appendicitis, and the most commonly applied diagnostic criterion for both modalities is appendiceal diameter. The classically described cut-off diameter for the diagnosis of appendicitis is 6 mm when using either imaging modality. To demonstrate the fallacy of using the same cut-off diameter for both CT and US in the diagnosis of appendicitis. We conducted a retrospective review of patients younger than 18 years who underwent both US and CT of the appendix within 24 h. The shortest transverse dimension of the appendix was measured at the level of the proximal, mid and distal appendix on US and CT images. We compared mean absolute difference in appendiceal diameter between US and CT, using the paired t-test. We reviewed exams of 155 children (58.7% female) with a mean age of 11.3 ± 4.2 years; 38 of the children (24.5%) were diagnosed with appendicitis. The average time interval between US and CT was 7.0 ± 5.4 h. Mean appendiceal diameter measured by CT was significantly larger than that measured by US in cases without appendicitis (5.3 ± 1.0 mm vs. 4.7 ± 1.1 mm, P < 0.0001) and in cases with appendicitis (8.3 ± 2.2 mm vs. 7.0 ± 2.0 mm, P < 0.0001). Mean absolute diameter difference at any location along the appendix was 1.3-1.4 mm in normal appendices and 2 mm in cases of appendicitis. Measured appendiceal diameter differs between US and CT by 1-2 mm, calling into question use of the same diameter cut-off (6 mm) for both modalities for the diagnosis of appendicitis. (orig.)

  12. Collagen fibril diameter and leather strength.

    Science.gov (United States)

    Wells, Hannah C; Edmonds, Richard L; Kirby, Nigel; Hawley, Adrian; Mudie, Stephen T; Haverkamp, Richard G

    2013-11-27

    The main structural component of leather and skin is type I collagen in the form of strong fibrils. Strength is an important property of leather, and the way in which collagen contributes to the strength is not fully understood. Synchrotron-based small angle X-ray scattering (SAXS) is used to measure the collagen fibril diameter of leather from a range of animals, including sheep and cattle, that had a range of tear strengths. SAXS data were fit to a cylinder model. The collagen fibril diameter and tear strength were found to be correlated in bovine leather (r(2) = 0.59; P = 0.009), with stronger leather having thicker fibrils. There was no correlation between orientation index, i.e., fibril alignment, and fibril diameter for this data set. Ovine leather showed no correlation between tear strength and fibril diameter, nor was there a correlation across a selection of other animal leathers. The findings presented here suggest that there may be a different structural motif in skin compared with tendon, particularly ovine skin or leather, in which the diameter of the individual fibrils contributes less to strength than fibril alignment does.

  13. Diameter Preserving Surjection on Alternate Matrices

    Institute of Scientific and Technical Information of China (English)

    Li Ping HUANG

    2009-01-01

    Let F be a field with |F| ≥ 3, Km be the set of all m × m (m ≥ 4) alternate matrices over F. The arithmetic distance of A, B ∈ Km is d(A, B) := rank(A- B). If d(A, B) = 2, then A and B are said to be adjacent. The diameter of Km is max{d(A, B) : A, B ∈ Km}. Assume that ψ : Km→ Km is a map. We prove the following are equivalent: (a) ψ is a diameter preserving surjection in both directions, (b) ψ is both an adjacency preserving surjection and a diameter preserving map, (c) ψ is a bijective map which preserves the arithmetic distance.

  14. Calibration of Laser Beam Direction for Inner Diameter Measuring Device

    Directory of Open Access Journals (Sweden)

    Tongyu Yang

    2017-02-01

    Full Text Available The laser triangulation method is one of the most advanced methods for large inner diameter measurement. Our research group proposed a kind of inner diameter measuring device that is principally composed of three laser displacement sensors known to be fixed in the same plane measurement position. It is necessary to calibrate the direction of the laser beams that are emitted by laser displacement sensors because they do not meet the theoretical model accurately. For the purpose of calibrating the direction of laser beams, a calibration method and mathematical model were proposed. The inner diameter measuring device is equipped with the spindle of the machine tool. The laser beams rotate and translate in the plane and constitute the rotary rays which are driven to scan the inner surface of the ring gauge. The direction calibration of the laser beams can be completed by the sensors’ distance information and corresponding data processing method. The corresponding error sources are analyzed and the validity of the method is verified. After the calibration, the measurement error of the inner diameter measuring device reduced from ± 25 μ m to ± 15 μ m and the relative error was not more than 0.011%.

  15. The Angular Diameter and Fundamental Parameters of Sirius A

    CERN Document Server

    Davis, J; North, J R; Robertson, J G; Tango, W J; Tuthill, P G

    2010-01-01

    The Sydney University Stellar Interferometer (SUSI) has been used to make a new determination of the angular diameter of Sirius A. The observations were made at an effective wavelength of 694.1 nm and the new value for the limb-darkened angular diameter is 6.048 +/- 0.040mas (+/-0.66%). This new result is compared with previous measurements and is found to be in excellent agreement with a conventionally calibrated measurement made with the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at 2.176 microns (but not with a second globally calibrated VLTI measurement). A weighted mean of the SUSI and first VLTI results gives the limb-darkened angular diameter of Sirius A as 6.041 +/- 0.017mas (+/-0.28%). Combination with the Hipparcos parallax gives the radius equal to 1.713 +/- 0.009R_sun. The bolometric flux has been determined from published photometry and spectrophotometry and, combined with the angular diameter, yields the emergent flux at the stellar surface equal to (5.32+/- 0.14)...

  16. The truth about small-diameter implants.

    Science.gov (United States)

    Christensen, Gordon J; Child, Paul L

    2010-05-01

    SDIs that are treatment planned correctly, placed and loaded properly, and are within a well-adjusted occlusion, are working in an excellent manner for the patients described in this article. It is time for those practitioners unfamiliar with SDIs and their uses to discontinue their discouragement of this technique. SDIs are easily placed, minimally invasive, and a true service to those patients described. They do not replace conventional diameter implants; however, they are a significant and important augmentation to the original root-form implant concept. There is obvious evidence of the growing acceptance of small-diameter implants by both general practitioners and specialists.

  17. THERMAL EVALUATION OF DIFFERENT DRIFT DIAMETER SIZES

    Energy Technology Data Exchange (ETDEWEB)

    H.M. Wade

    1999-01-04

    The purpose of this calculation is to estimate the thermal response of a repository-emplaced waste package and its corresponding drift wall surface temperature with different drift diameters. The case examined is that of a 21 pressurized water reactor (PWR) uncanistered fuel (UCF) waste package loaded with design basis spent nuclear fuel assemblies. This calculation evaluates a 3.5 meter to 6.5 meter drift diameter range in increments of 1.0 meters. The time-dependent temperatures of interest, as determined by this calculation, are the spent nuclear fuel cladding temperature, the waste package surface temperature, and the drift wall surface temperature.

  18. Shaft Diameter Measurement Using Structured Light Vision.

    Science.gov (United States)

    Liu, Siyuan; Tan, Qingchang; Zhang, Yachao

    2015-08-12

    A method for measuring shaft diameters is presented using structured light vision measurement. After calibrating a model of the structured light measurement, a virtual plane is established perpendicular to the measured shaft axis and the image of the light stripe on the shaft is projected to the virtual plane. On the virtual plane, the center of the measured shaft is determined by fitting the projected image under the geometrical constraints of the light stripe, and the shaft diameter is measured by the determined center and the projected image. Experiments evaluated the measuring accuracy of the method and the effects of some factors on the measurement are analyzed.

  19. Shaft Diameter Measurement Using Structured Light Vision

    Directory of Open Access Journals (Sweden)

    Siyuan Liu

    2015-08-01

    Full Text Available A method for measuring shaft diameters is presented using structured light vision measurement. After calibrating a model of the structured light measurement, a virtual plane is established perpendicular to the measured shaft axis and the image of the light stripe on the shaft is projected to the virtual plane. On the virtual plane, the center of the measured shaft is determined by fitting the projected image under the geometrical constraints of the light stripe, and the shaft diameter is measured by the determined center and the projected image. Experiments evaluated the measuring accuracy of the method and the effects of some factors on the measurement are analyzed.

  20. Influence of tube's diameter on boiling heat transfer performance in small diameter tubes

    Science.gov (United States)

    Gan, Chengjun; Wang, Weicheng; Zhang, Lining

    1998-03-01

    This paper reports the experiments of evaporation study in 6 mm inner copper diameter tubes using HFC-134a, HCFC-22 and CFC-12 as working fluid. The results show that the evaporation heat transfer coefficient increases with the decreasing of inner diameter of tubes. A new concept of non-dimensional tube diameter U is proposed in this paper for correction of the influence of the tube diameter on the evaporation heat transfer coefficient. And further, a convenient empirical correction method is presented.

  1. Influence of Tube‘s Diameter on Boling Heat Transfer Performance in Small Diameter Tubes

    Institute of Scientific and Technical Information of China (English)

    GanChengjun; WangWeicheng; 等

    1998-01-01

    This paper reports the experiments of evaporation study in 6 mm inner copper diameter tubes using HFC-134a,HCFC-22 and CFC-12 as working fluid.The results show that the evaporation heat transfer cofeeicient increasese with the decreasing of inner diameter of tubes,A new concept of nondimensional tube diameter U is proposed in this paper for correction of the influence of the tube diameter on the evaporation heat transfer coefficient.And further,a conveinent empirical correction method is preseted.

  2. Influence of Nanowire Diameter on Structural and Optical Properties of cu Nanowire Synthesized in Anodic Aluminium Oxide Film

    Science.gov (United States)

    Cetinel, A.; Özcelik, Z.

    2016-11-01

    Copper (Cu) nanowire arrays embedded in anodic aluminium oxide films (AAO) on aluminium substrate have been synthesized by alternating current electrochemical deposition. Two-step anodization process has been performed to get the through-hole AAO with ordered nanochannels in 0.3M oxalic acids at DC voltages 30, 40, 50 and 60V, respectively. Structural characterization of the Cu nanowires has been analyzed by scanning electron microscopy (SEM) and X-ray diffraction (or) X-ray diffractometer (XRD). Our SEM analysis has revealed that the diameters of vertically oriented Cu nanowires are 15, 25, 45 and 60nm and the length of Cu nanowires having high packing density is about 15μm. XRD measurement has indicated that polycrystalline Cu nanowires prefer growth orientation along the (111) direction. Optical measurements show that reflection of the Cu nanowires/AAO on aluminium reduces with decreasing diameter of the Cu nanowires. This effect can be associated with increased light scattering from metal nanoparticles near their localized plasmon resonance frequency depending on the size and shape of the nanoparticles.

  3. Photoacoustic determination of blood vessel diameter.

    NARCIS (Netherlands)

    Kolkman, R.G.; Klaessens, J.H.G.M.; Hondebrink, E.; Hopman, J.C.W.; Mul, F.F. de; Steenbergen, W.; Thijssen, J.M.; Leeuwen, T.G. van

    2004-01-01

    A double-ring sensor was applied in photoacoustic tomographic imaging of artificial blood vessels as well as blood vessels in a rabbit ear. The peak-to-peak time (tau(pp)) of the laser (1064 nm) induced pressure transient was used to estimate the axial vessel diameter. Comparison with the actual ves

  4. Virtual Orthogonal Experiment Study on Needle Piercing Extrusion Process of Inconel690 Alloy Large-Diameter Thick-Walled Tube%基于虚拟正交试验的Inconel690合金大口径厚壁管挤压工艺仿真

    Institute of Scientific and Technical Information of China (English)

    张保军; 杨合; 郭良刚; 谷瑞杰; 寇永乐

    2013-01-01

    It is an important issue for the optimization design and refined control of extrusion process of large-diameter hard wrought alloy profiles to reveal the effects of forming parameters on the process and to determine the reasonable range of each forming parameter. And it's also significant for the R&D, debugging and application of the large tonnage (such as 200 MN) extrusion press. Therefore, we developed an applicable and reliable FE model for the needle piercing extrusion process for Inconel690 alloy large-diameter thick-walled tube (Φ420 mm×60 mm) under the DEFORM-2D software environment. And the effects of forming parameters (i.e. extruding ratio A, die taper angle a, sizing belt length h, billet initial temperature T and ram speed v) on the peak temperature of billet Tmax, the peak damage of billet Dmax, the uniformity of flow rate at die export Fsdv and the peak extrusion load Lmax were investigated using virtual orthogonal experiment based on the developed FE model. The results show that the order of forming parameters' significance to rmax, Dmax, Fsdv and Lmax are T>v>λ>h>a, a>v≈λ>T>h, h>v>T>α>λ, and λ>T>α>v>h, respectively. Comprehensively considering the quality of the extruded tube and the extrusion load, we pointed out that the reasonable ranges of forming parameters are as follows: λ=5.74~6.37, λ=35°~45°, h=60~120 mm, T=1080~1180 ℃, and v=150~250 mm/s.%研究挤压成形参数影响规律并确定合理的参数取值范围,是开发难变形合金大型型材挤压工艺技术和挤压过程精细化控制,以及大吨位(如2万吨)挤压机的研发、调试及应用迫切需要开展的重要内容.基于DEFORM-2D平台,以规格为Φ420 mm×60mm的难变形Inconel690合金管材穿孔针挤压为研究对象,建立了适用、可靠的无缝管材穿孔L针挤压过程的有限元仿真模型;选取挤压比λ、模角α、定径带长度h、坯料初始温度T、挤压速度v等重要成形参数为影响因素,以坯料

  5. Effect of Hot Rolling Parameters on Microstructures and Properties of 316LN Stainless Steel Pipes with Large Diameter and Thick Wall%热轧参数对大口径厚壁316LN不锈钢管组织和性能的影响研究

    Institute of Scientific and Technical Information of China (English)

    罗毅军; 陈海涛; 何昌明

    2016-01-01

    The 316LN stainless steel pipes with large diameter and thick wall were produced by Pelger pipe mill at different rolling deformation and rolling temperature.The microstructures of the hot-rolled pipes and the solution state pipes were observed by using the optical microscope.The tensile mechanical properties of the solution state pipes at room temperature were tested by using the universal testing machine.The results show that,increasing the rolling deformation can promote the nucleation process of dynamic recrystallization and refine the grains;increasing the hot rolling temperature can promote the growth process of dynamic recrystallization and coarse grains;hot rolled tube of incomplete dynamic recrystallization can produce the abnormal growth of the recrystallized grains and mixed crystal during the solution heat treatment,and mechanical properties are reduced;increasing the rolling deformation and reducing the rolling temperature can refine the grain size of the solution state pipes and improve the mechanical properties.%使用皮尔格管材轧机在不同轧制变形量和轧制温度下热轧生产了大口径厚壁316LN不锈钢管,采用光学显微镜观察了热轧态管材和固溶态管材的显微组织,采用万能试验机测定了固溶态管材的室温拉伸力学性能.结果表明:提高轧制变形量能促进热轧过程中动态再结晶的形核过程,细化动态再结晶晶粒;提高热轧温度能促进热轧过程中动态再结晶的长大过程,粗化动态再结晶晶粒;不完全动态再结晶的热轧管材在固溶热处理过程中会发生已再结晶晶粒的异常长大,产生混晶,降低力学性能;提高轧制变形量和降低轧制温度可以细化固溶态管材的晶粒尺寸,提高力学性能.

  6. Empirical processes with bounded \\psi_1 diameter

    CERN Document Server

    Mendelson, Shahar

    2010-01-01

    We study the empirical process indexed by F^2=\\{f^2 : f \\in F\\}, where F is a class of mean-zero functions on a probability space. We present a sharp bound on the supremum of that process which depends on the \\psi_1 diameter of the class F (rather than on the \\psi_2 one) and on the complexity parameter \\gamma_2(F,\\psi_2). In addition, we present optimal bounds on the random diameters \\sup_{f \\in F} \\max_{|I|=m} (\\sum_{i \\in I} f^2(X_i))^{1/2} using the same parameters. As applications, we extend several well known results in Asymptotic Geometric Analysis to any isotropic, log-concave ensemble on R^n.

  7. Transfinite diameter of Bernstein sets in

    Directory of Open Access Journals (Sweden)

    Bialas-Cież Leokadia

    2002-01-01

    Full Text Available Let be a compact set in satisfying the following generalized Bernstein inequality: for each such that , for each polynomial of degree where is a constant independent of and , is an infinite set of natural numbers that is also independent of and . We give an estimate for the transfinite diameter of the set : For satisfying the usual Bernstein inequality (i.e., , we prove that

  8. 29 mm Diameter Test Target Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Naranjo, Angela Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Romero, Frank Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-15

    The Northstar target for Mo99 production is made up of Mo100 disks in a stack separated by coolant gaps for helium flow. A number of targets have been tested at ANL for both production of Mo99 and for thermal-hydraulic performance. These have all been with a 12 mm diameter target, even while the production goals have increased the diameter to now 29 mm. A 29 mm diameter target has been designed that is consistent with the ANL beam capabilities and the capabilities of the helium circulation system currently in use at ANL. This target is designed for 500 μA at 35 MeV electrons. While the plant design calls for 42 MeV, the chosen design point is more favorable and higher power given the limits of the ANL accelerator. The intended beam spot size is 12 mm FWHM, but the thermal analysis presented herein conservatively assumed a 10 mm FWHM beam, which results in a 44% higher beam current density at beam center.

  9. Clinical application and therapeutic effectiveness of large diameter head metal-on-metal total hip replacement%金属对金属大直径股骨头全髋关节置换术的临床应用及近期疗效观察

    Institute of Scientific and Technical Information of China (English)

    刘二涛; 徐皓; 陈建梅; 姚晓东; 李金泉

    2013-01-01

    Objective To explore the short-term results of total hip replacement THR ) using large diameter heads( LDH )in metal-on-metal( MOM )articulation. Methods A consecutive series of 34 patients( 34 hips )who underwent THR using LDH in MOM articulation were studied. The results were e-valuated both clinically and radio graphically. Clinical outcomes were evaluated according to the Harris e-valuation score and the R0M( Range of motion ). Acetabular position, components migration and bone changes around the implant were measured radiographically. Results The average follow-up period of all 34 patients was 18. 7 months. There was no bright line around the prosthesis. No complications such as os-teolysis, prosthetic loosening, heterotopic ossification and prosthesis fracture occurred. The average Harris hip score at the last follow-up was significantly improved compared with the preoperative scores( 87. 82 points versus 35. 29 points ). The postoperative ROM of all patients improved remarkably. Conclusion The short-term results of LDH in MOM total hip replacement on hip osteoarthritis, aseptic femoral head necrosis, femur neck fracture and congenital hip hypoplasia are excellent. But the long-term results of THR using LDH in MOM articulation still need further investigation.%目的 总结金属对金属大直径股骨头全髋关节置换术(total hip replacement,THR)的近期疗效.方法 回顾性分析行金属对金属大直径股骨头THR患者34例34髋.临床评估以Harris评分及髋关节活动度为标准.影像学根据双髋关节正位片,观察髋臼、股骨假体的位置及周围骨质的改变.结果 34例患者平均随访18.7个月.术后均无假体周围透亮线产生,无骨溶解、假体松动、异位骨化及假体断裂等并发症.Harris评分由术前的20~48分,平均(35.29±8.59)分,提高至术后随访时的76~96分,平均(87.82±5.12)分.所有患者髋关节活动度术后显著提高.结论 采用金属对金属大直径股骨

  10. On the Connectedness and Diameter of a Geometric Johnson Graph

    CERN Document Server

    Bautista-Santiago, Crevel; Fabila-Monroy, Ruy; Flores-Peñaloza, David; González-Aguilar, Hernán; Lara, Dolores; Sarmiento, Eliseo; Urrutia, Jorge

    2012-01-01

    Let $P$ be a set of $n$ points in general position in the plane. A subset $I$ of $P$ is called an \\emph{island} if there exists a convex set $C$ such that $I = P \\cap C$. In this paper we define the \\emph{generalized island Johnson graph} of $P$ as the graph whose vertex consists of all islands of $P$ of cardinality $k$, two of which are adjacent if their intersection consists of exactly $l$ elements. We show that for large enough values of $n$, this graph is connected, and give upper and lower bounds on its diameter.

  11. Finned Small Diameter Tube Heat Exchanger

    Science.gov (United States)

    Dang, Chaobin; Daiguji, Hirofumi; Hihara, Eiji; Tokunaga, Masahide

    The performance of fined small tube heat exchangers was investigated both experimentally and theoretically. The Inner diameters of tubes were 1.0mm, 2.1mm and 4.0mm. Exchanged heat and pressure drop obtained from numerical simulation agreed well with the experimental ones. Calculation results show that the volume of a 2.0mm tube heat exchanger can be reduced to 33% of that of a 4mm tube heat exchanger with the same capacity. In addition the distribution of two-phase flow in a branching unit was investigated by measuring downstream temperature distribution. The flow distribution in a branching unit strongly affects the exchanged heat.

  12. Retrobulbar diameter of optic nerve in glaucoma

    Directory of Open Access Journals (Sweden)

    Stefanović Ivan

    2009-01-01

    Full Text Available Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05. Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values, even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.

  13. Measurement of Diameter Changes during Irradiation Testing

    Energy Technology Data Exchange (ETDEWEB)

    Davis, K. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Knudson, D. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Crepeau, J. C. [Univ. of Idaho, Idaho Falls, ID (United States); Solstad, S. [Inst. for Energy Technologoy, Halden (Norway)

    2015-03-01

    New materials are being considered for fuel, cladding, and structures in advanced and existing nuclear reactors. Such materials can experience significant dimensional and physical changes during irradiation. Currently in the US, such changes are measured by repeatedly irradiating a specimen for a specified period of time and then removing it from the reactor for evaluation. The time and labor to remove, examine, and return irradiated samples for each measurement makes this approach very expensive. In addition, such techniques provide limited data and handling may disturb the phenomena of interest. In-pile detection of changes in geometry is sorely needed to understand real-time behavior during irradiation testing of fuels and materials in high flux US Material and Test Reactors (MTRs). This paper presents development results of an advanced Linear Variable Differential Transformer-based test rig capable of detecting real-time changes in diameter of fuel rods or material samples during irradiation in US MTRs. This test rig is being developed at the Idaho National Laboratory and will provide experimenters with a unique capability to measure diameter changes associated with fuel and cladding swelling, pellet-clad interaction, and crud buildup.

  14. Sagittal Abdominal Diameter: Application in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Thaís Da Silva-Ferreira

    2014-05-01

    Full Text Available Excess visceral fat is associated with cardiovascular risk factors. Sagittal abdominal diameter (SAD has recently been highlighted as an indicator of abdominal obesity, and also may be useful in predicting cardiovascular risk. The purpose of the present study was to review the scientific literature on the use of SAD in adult nutritional assessment. A search was conducted for scientific articles in the following electronic databases: SciELO , MEDLINE (PubMed and Virtual Health Library. SAD is more associated with abdominal fat (especially visceral, and with different cardiovascular risk factors, such as, insulin resistance, blood pressure, and serum lipoproteins than the traditional methods of estimating adiposity, such as body mass index and waist-to-hip ratio. SAD can also be used in association with other anthropometric measures. There are still no cut-off limits established to classify SAD as yet. SAD can be an alternative measure to estimate visceral adiposity. However, the few studies on this diameter, and the lack of consensus on the anatomical site to measure SAD, are obstacles to establish cut-off limits to classify it.

  15. Fire protection covering for small diameter missiles

    Science.gov (United States)

    Riccitiello, S. R.; Sawko, P. M. (Inventor)

    1979-01-01

    Flexible intumescent protection sheeting of unusually uniform thickness were prepared from epoxy-polysulfide compositions, containing microfibers and the ammonium salt of 1,4-nitroaniline-2-sulfonic acid, as disclosed in U.S. Pat. No. 3,663,464, except that an ammonium salt particle size in the order of 5 to 8 microns and a fiber size of about 1/128th inch in length and 3 to 5 microns in diameter were found critical to obtain the required density of 1.46 to 1.50 g/cc. The insulation sheeting was prepared by a continuous process involving vacuum mixing, calendering, and curing under very strict conditions which depend to some extent upon the thickness of the sheet produced.

  16. 基于数值模拟的海上风电大直径桩桩土相互作用研究%Study on Pile-soil Interaction of Large Diameter Pile Foundation of Offshore Wind Power Based on Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    孙希; 黄维平

    2015-01-01

    As a method that can describe the non-linear characteristics of pile-soil, the p-y curve method is widely used for the analysis of laterally loaded piles. Because the recommended p-y curve formulations are based on the results of lateral load test on instrumented piles with diameter less than or equal to 3 m, the suitability of p-y method for the monopile with diameter of 4-6 m or even more used in offshore wind farms needs to be proved. The simulated data are processed and analyzed, then using the finite element software of ABAQUS and SACS to analyze the monopile with a diameter of 6.2 m. Through the comparative analysis of examples, the validity and applicability of the simulated data are proved. The simulation results show that the p-y curves recommended by standards is more safe.%p-y曲线能够反映桩土非线性特征,是分析水平受荷桩常采用的方法。但现场多为3m以内的试桩,对于4~6m甚至更大的海上风电单桩基础结构而言,其适用性值得商榷。为此,采用数值仿真技术对海上风电基础结构大直径钢管桩现场试桩试验进行了有限元数值模拟,分别采用ABAQUS和SACS软件对6.2 m直径桩进行了对比分析,证明了数值实验得到的大直径桩p-y数据的有效性;并将数值实验得到大直径桩p-y数据通过软件SACS与规范推荐的p-y曲线计算结果进行对比,结果表明,规范推荐的p-y曲线偏安全。

  17. 利用电镀铜填充微米盲孔与通孔之应用%Applications of Microvia and Through-Hole Filling by Copper Electroplating

    Institute of Scientific and Technical Information of China (English)

    窦维平

    2012-01-01

    电子产品之高密度内连结制程技术,从上游的半导体制程到中游的封装基板制程,一直到下游的电路板制程,似乎都需要依赖电镀铜填孔技术.近几年来,电镀铜填孔技术日趋受到重视,相关专秘的电镀配方、技术、设备以及周边配套的仪器设施等,如雨后春笋般地发展起来.以往常用但未能深入了解的电镀铜技术有了跃进式的突破,值得探讨.这些技术的发展,似乎有着轮回应用的走势,即下游电路板的电镀铜制程技术似乎渐渐朝半导体制程技术发展,因此衍生出电镀铜填充盲孔的制程技术;而上游的半导体制程工艺中以往没有所谓的镀通孔(PTH),如今却因为3D芯片整合的需要,出现了所谓的穿硅孔(TSV),而所谓的TSV,其实与镀通孔具有类似的制程步骤以及相同的功能与目的,只是介电材料、设备等不同而已.针对目前电镀铜填充微米级盲孔与通孔的相关技术作概略式的介绍与回顾.%The interconnect process technology of electronic products, from the upstream semiconductor process to the midstream packaging process and to the downstream printed circuit board (PCB) process, greatly need copper filling technology by electroplating. Therefore, copper filling by electroplating is being taken much attention. The related confidential formulas, technologies, tools and corresponding instruments are being developed as bamboo shoots after a spring rain. Hence, the copper electroplating technology, which is often used but not understood well, has been greatly improved and explored. Interestingly, the copper metallization technology has a trend that rotates between two industry fields, that is, the development of copper electroplating in downstream PCB gradually approaches to that of semiconductor. Therefore, microvia filling by copper electroplating emerges in PCB. On the other hand, the upstream semiconductor process had no plated through hole

  18. Propagation characteristics of the silica and silicon subwavelength-diameter hollow wire waveguides

    Institute of Scientific and Technical Information of China (English)

    Man Wu; Weiqing Huang; Lingling Wang

    2008-01-01

    @@ The basic propagation properties of the silica and silicon subwavelength-diameter hollow wire waveguides have been investigated by comparison. It shows that the silica and silicon subwavelength-diameter hollow wire waveguides have some interesting properties, such as enhanced evanescent field in the cladding, enhanced intensity in the hollow core, and large waveguide dispersion. For the different confinement ability, the enhanced field in the hollow core and cladding of the silica subwavelength-diameter hollow wire is much stronger than that of the silicon one for the same size.

  19. LED-based digital diameter measurement

    Science.gov (United States)

    Kleuver, Wolfram; Becker, Lothar

    1995-01-01

    This paper presents a new industrial sensor for measuring diameters of extreme thin objects. The system is divided in two parts. The first is the emitter and the second the receiver. It is possible to use this system for the automatic inspection of files and wires in the textile industries and wire works. Another application for the sensor is the control of production of chemical files in an extruder. Furthermore we can measure more than one object in the lightbeam because we get information not only about the dimensions also about the position of the objects in the beam. The innovation in this system is the using of a light emitting diode (LED) as emitter and the realization of a long distance of about two or more meters between the two sensorheads. The results of this development are a special kind of optical layout in the emitter to reduce the loss of intensity and minimize the divergence of the lightbeam. It is not necessary to develop an intensity distribution, which is equal over the complete width of the sensorhead. We can show that we have a better dynamic in the system with this feature. The experiments prove that we get the same resolution as a laserbeamsensor. Furthermore one advantage is the eye-safety.

  20. Experimental and Numerical Investigation of a 60cm Diameter Bladeless Fan

    OpenAIRE

    mohammad jafari; Hossein Afshin; Bijan Farhanieh; Hamidreza bozorgasareh

    2016-01-01

    Bladeless fan is a novel type of fan with an unusual geometry and unique characteristics. This type of fan has been recently developed for domestic applications in sizes typically up to 30cm diameter. In the present study, a Bladeless fan with a diameter of 60cm was designed and constructed, in order to investigate feasibility of its usage in various industries with large dimensions. Firstly, flow field passed through this fan was studied by 3D modeling. Aerodynamic and aeroacoust...

  1. Atomistic Failure Mechanism of Single Wall Carbon Nanotubes with Small Diameters

    Institute of Scientific and Technical Information of China (English)

    JI Dong; GAO Xiang; KONG Xiang-Yang; LI Jia-Ming

    2007-01-01

    @@ Single wall carbon nanotubes with small diameters (< 5.0 (A)) subjected to bending deformation are simulated by orthogonal tight-binding molecular dynamics approach. Based on the calculations of C-C bond stretching and breaking in the bending nanotubes, we elucidate the atomistic failure mechanisms of nanotube with small diameters. In the folding zone of bending nanotube, a large elongation of C-C bonds occurs, accounting for the superelastic behaviour.

  2. Mockup Small-Diameter Air Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    A. Poerschke and A. Rudd

    2016-05-01

    This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to be brought easily within conditioned space via interior partition walls. Centrally locating the air hander unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives an equal amount of airflow, regardless of the duct position on the box. Furthermore, within a reasonable set of length restrictions, each duct continues to receive similar airflow. The design method uses an additive approach to reach the total needed zonal airflow. Once the cubic feet per minute needed to satisfy the thermal load of a zone has been determined, the total number of duct runs to a zone can be calculated by dividing the required airflow by the standard airflow from each duct. The additive approach greatly simplifies the design effort and reduces the potential for duct design mistakes to be made. Measured results indicate that this plenum design can satisfy the heating load. However, the total airflow falls short of satisfying the cooling load in a hypothetical building. Static pressure inside the plenum box of 51.5 Pa limited the total airflow of the attached mini-split heat pump blower, thus limiting the total thermal capacity. Fan energy consumption is kept to 0.16 to 0.22 watt/CFM by using short duct runs and smooth duct material.

  3. Body diameters in 3 - 6 years old children from Plovdiv

    Directory of Open Access Journals (Sweden)

    Tineshev Slavi

    2013-01-01

    Full Text Available The purpose of the research is to analyze the body diameters in 3-6 year old children. The biacromial diameters were taken as well as the two chest diameters, the bicristal and bitrohanterial diameters in 316 children (157 boys and 159 girls 3, 4, 5 and 6 years of age attending kindergarten in Plovdiv. The analysis shows that all diameters, with the exception of the bitrohanterial have higher values in boys. The absolute year's increment of the diameters is greater in girls. The growth velocity of the researched features is greatest at the age of 3-4 and 4-5, decreasing at different rates for the different features at the age of 5-6. The only exception is the sagittal chest diameter in both sexes and the bitrohanterial diameters in girls.

  4. The diameter-dependent photoelectrochemical performance of silicon nanowires.

    Science.gov (United States)

    Zhang, Bing-Chang; Wang, Hui; He, Le; Duan, Chun-Yang; Li, Fan; Ou, Xue-Mei; Sun, Bao-Quan; Zhang, Xiao-Hong

    2016-01-25

    We demonstrate the first systematic study of the diameter-dependent photoelectrochemical performance of single silicon nanowires within a broad size range from 200 to 2000 nm. SiNWs with a diameter of 1415 nm exhibit the highest solar energy conversion efficiency, which can be mainly traced to their diameter-dependent light absorption properties.

  5. Research on Strategy of Two Robotic Fishes' Collaboration to Pass Through Hole%仿真机器鱼双鱼协作过孔策略的研究

    Institute of Scientific and Technical Information of China (English)

    张进; 李淑琴; 侯霞

    2013-01-01

    Many factors such as wave power and complex environment make it difficult to control multi-robot fishes ' behaviors and make them cooperate to complete a task. According to the project of Two Robotic Fishes Collaborate through the Hole in the Water Robot Competition, this paper studied the water robot control method from two aspects : emulational robotic fish control and collaboration strategy. The water robot control employs the planning method based on the target area. This method can overcome the problem that the robotic fishes can not reach the target point accurately because of water wave' s interference. The emulational robotic fishes can perceive external environments and their location, and then change their roles appropriately to achieve the task of heading ball collaboratively to pass through the hole. The proposed algorithm won the championship in the match event of Two Robotic Fishes' Collaboration to Pass through Hole in the 2011 RoboCup Competition. The studies about robotic fish control and collaboration strategy provide some reference for the water robot control research and have very important significance.%水中机器人受到水波动力及水下复杂环境等相关因素的影响,导致行为控制和多机器鱼之间协作完成任务成为难点.针对水中机器人大赛中的双鱼协作过孔项目,从仿真机器鱼控制及协作策略两方面对水中机器人的控制方法进行了研究.水中机器人控制采用基于目标区域的路径规划方法,克服了仿真机器鱼由于水波动干扰而无法准确到达目标点的问题.仿真机器鱼通过不断感知外界环境和自身位置,合理进行角色变换,从而有效地实现了协作带球过孔的任务.该算法在2011中国机器人大赛暨RoboCup公开赛水中机器人双鱼协作过孔项目中获得冠军.对仿真机器鱼控制及协作策略的研究,为日后实体水中机器人的控制研究提供了参考,具有重要意义.

  6. Narrowing SWNT diameter distribution using size-separated ferritin-based Fe catalysts.

    Science.gov (United States)

    Durrer, Lukas; Greenwald, Jason; Helbling, Thomas; Muoth, Matthias; Riek, Roland; Hierold, Christofer

    2009-09-02

    Sensors and devices made from single-walled carbon nanotubes (SWNTs) are most often electrically probed through metal leads contacting the semiconducting SWNTs (s-SWNTs). Contact barriers in general and Schottky barriers (SBs) in particular are usually obtained at a metal-semiconductor interface. The unique one-dimensional structure (1D) of SWNTs allows tailoring of the SB heights through the contact metal type and the size of the s-SWNT bandgap. A large workfunction reduces the SB height (e.g. using Pd as the metal contact material). The bandgap of an SWNT is inversely proportional to its diameter. Ohmic contacts--the preferable choice--are achieved for s-SWNTs with diameters greater than 2 nm on Pd metal leads. SWNT device reproducibility, on the other hand, requires a narrow distribution of the SWNT diameters. Here, we present a method to fabricate SWNTs with a large and adjustable mean diameter (1.9-2.4 nm) and very narrow diameter distribution (+/- 0.27 nm at mean diameter 1.9 nm). The results are achieved through a size separation of the ferritin catalyst particles by sedimentation velocity centrifugation prior to their use in the chemical vapor deposition (CVD) formation of SWNTs.

  7. Narrowing SWNT diameter distribution using size-separated ferritin-based Fe catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Durrer, Lukas; Helbling, Thomas; Muoth, Matthias; Hierold, Christofer [Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zuerich, CH-8092 Zurich (Switzerland); Greenwald, Jason; Riek, Roland, E-mail: lukas.durrer@micro.mavt.ethz.c [Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zuerich (Switzerland)

    2009-09-02

    Sensors and devices made from single-walled carbon nanotubes (SWNTs) are most often electrically probed through metal leads contacting the semiconducting SWNTs (s-SWNTs). Contact barriers in general and Schottky barriers (SBs) in particular are usually obtained at a metal-semiconductor interface. The unique one-dimensional structure (1D) of SWNTs allows tailoring of the SB heights through the contact metal type and the size of the s-SWNT bandgap. A large workfunction reduces the SB height (e.g. using Pd as the metal contact material). The bandgap of an SWNT is inversely proportional to its diameter. Ohmic contacts-the preferable choice-are achieved for s-SWNTs with diameters greater than 2 nm on Pd metal leads. SWNT device reproducibility, on the other hand, requires a narrow distribution of the SWNT diameters. Here, we present a method to fabricate SWNTs with a large and adjustable mean diameter (1.9-2.4 nm) and very narrow diameter distribution ({+-} 0.27 nm at mean diameter 1.9 nm). The results are achieved through a size separation of the ferritin catalyst particles by sedimentation velocity centrifugation prior to their use in the chemical vapor deposition (CVD) formation of SWNTs.

  8. Interlayer locking and atomic-scale friction in commensurate small-diameter boron nitride nanotubes

    Science.gov (United States)

    Shin, Homin; Kim, Keun Su; Simard, Benoit; Klug, Dennis D.

    2017-02-01

    Density functional theory applied to small-diameter boron nitride nanotubes (BNNTs) finds out-of-plane structural buckling in contrast to large-diameter tubes that exhibit faceting. Buckling significantly affects interlayer interactions in commensurate double-walled BNNTs. Energy corrugation amplitudes in relative motions of BNNT walls change up to fourfold, depending on interlayer registry relaxation, in marked contrast to carbon nanotubes. Large differences between relaxed and unrelaxed energy corrugations of BNNTs could yield energy dissipation via the strain-induced anelastic relaxation of interlayer locking (or "lattice kinks"), which can be exploited for mechanical damping applications.

  9. The k-Diameter of a Kind of Circulant Graph

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-di

    2004-01-01

    The diameter of a graph G is the maximal distance between pairs of vertices of G. When a network is modeled as a graph,diameter is a measurement for maximum transmission delay. The k-diameter dk(G) of a graph G, which deals with k internally disjoint paths between pairs of vertices of G, is a extension of the diameter of G. It has widely studied in graph theory and computer science. The circulant graph is a group-theoretic model of a class of symmetric interconnection network. Let Cn(i, ) be a circulant graph of order n whose spanning elements are i and , where n≥4 and n is even. In this paper, the diameter, 2-diameter and 3-diameter of the Cn(i,) are all obtained if gcd(n,i)=1, where the symbol gcd(n,i) denotes the maximum common divisor of n and i.

  10. Tool Geometry for Friction Stir Welding—Optimum Shoulder Diameter

    Science.gov (United States)

    Mehta, M.; Arora, A.; de, A.; Debroy, T.

    2011-09-01

    The most important geometric parameter in the friction stir welding (FSW) tool design is the shoulder diameter, which is currently estimated by trial and error. Here, we report a combined experimental and theoretical investigation on the influence of shoulder diameter on thermal cycles, peak temperatures, power requirements, and torque during FSW of AA7075-T6. An optimum tool shoulder diameter is identified using a three-dimensional, heat transfer and materials flow model. First, the predictive capability of the model is tested by comparing the computed values of peak temperature, spindle power, and torque requirements for various shoulder diameters against the corresponding experimental data. The change in the values of these variables with shoulder diameter is correctly predicted by the model. The model is then used to identify the optimum tool shoulder diameter that facilitates maximal use of the supplied torque in overcoming interfacial sticking. The tool with optimum shoulder diameter is shown to result in acceptable yield strength (YS) and ductility.

  11. Characteristics of Angora rabbit fiber using optical fiber diameter analyzer.

    Science.gov (United States)

    Rafat, S A; de Rochambeau, H; Brims, M; Thébault, R G; Deretz, S; Bonnet, M; Allain, D

    2007-11-01

    An experiment was conducted to describe the characteristics of Angora rabbit fiber using optical fiber diameter analyzer (OFDA). A total of 349 fleece samples were collected from 60 French Angora rabbits. Recorded measurements of OFDA were as follows: mean fiber diameter, CV of fiber diameter, comfort factor, spinning fineness, mean fiber curvature, SD of fiber curvature, mean opacity of fibers, percentage of medullated fibers, mean fiber diameter along the length, and SD of fiber diameter along the length. Comfort factor is the percentage of fibers less than or equal to 30 microns. The main effects included in the mixed model were fixed effects of group, harvest season, and age and a random effect of animal. Correlations among total fleece weight, compression, and OFDA measurements were calculated. Mean fiber diameter was lower than the fiber diameter along the length. Mean percentage of medullated fibers was very low and ranged from 0.1 to 7.3%. The mean comfort factor was 97.5% and ranged from 93.3 to 99.8%. The mean fiber curvature was 40.1 degrees/mm. The major changes in Angora fleece characteristics from 8 to 105 wk of age were an increase in fiber diameter, CV of fiber diameter, mean fiber diameter along the length and curvature, and a decrease in compression and comfort factor. The effect of harvest season was significant on some fiber characteristics. Mean fiber diameter and the mean fiber diameter along the length had a positive correlation with total fleece weight. The OFDA methodology is a method to evaluate fiber diameter, CV of fiber diameter, and bristle content through measuring of the comfort factor. However, OFDA is not adapted for measuring opacity or size of the medulla, or both, in Angora wool and needs a new definition or a special calibration. The spinning fineness should be redefined and adapted for Angora rabbits.

  12. Estimation of genetic parameters for wool fiber diameter measures.

    Science.gov (United States)

    Iman, N Y; Johnson, C L; Russell, W C; Stobart, R H

    1992-04-01

    Genetic and phenotypic correlations and heritability estimates of side, britch, and core diameters; side and britch CV; side and britch diameter difference; and clean fleece weight were investigated using 385 western white-faced ewes produced by 50 sires and maintained at two locations on a selection study. Data were analyzed using analysis of variance procedures, and effects in the final model included breed of sire-selection line combination, sire within breed-selection line, and location. Heritabilities were estimated by paternal half-sib analysis. Sires within breed-selection line represented a significant source of variation for all traits studied. Location had a significant effect on side diameter, side and britch diameter difference, and clean fleece weight. Age of ewe only affected clean fleece weight. Phenotypic and genetic correlations among side, britch, and core diameter measures were high and positive. Phenotypic correlations ranged from .68 to .75 and genetic correlations ranged from .74 to .89. The genetic correlations between side and britch diameter difference and side diameter or core diameter were small (-.16 and .28, respectively). However, there was a stronger genetic correlation between side and britch diameter difference and britch diameter (.55). Heritability of the difference between side and britch diameter was high (.46 +/- .16) and similar to heritability estimates reported for other wool traits. Results of this study indicate that relatively rapid genetic progress through selection for fiber diameter should be possible. In addition, increased uniformity in fiber diameter should be possible through selection for either side and britch diameter difference or side or britch CV.

  13. Security Technologies on the Hoisting Safety of Multi-Winch Sinking Platform in Constructing Large Diameter Ultra-Deep Shaft%大直径超深竖井施工吊盘多稳车提升安全保障技术

    Institute of Scientific and Technical Information of China (English)

    孙会贞; 何磊; 崔喜旺; 付宏伟

    2015-01-01

    净直径10 m、深度1503.9 m的思山岭铁矿副井凿井吊盘采用10绳悬吊,吊盘提升面临受力不均等风险。为保障该竖井吊盘提升安全,开发了稳车集散控制系统保障吊盘运行同步;在吊盘悬吊点布置液压张力自动平衡系统,消除各悬吊钢丝绳张力差,避免钢丝绳集中受力、稳车过载的危险发生;开发了吊盘钢丝绳张力在线监测系统,实时监测钢丝绳受力状态,实现受力异常情况下警报停机等应急动作。该技术在思山岭铁矿副井工程得到了成功的应用,保障了凿井安全,提高了吊盘提升、下放的效率。%Sishanling Iron mine’s auxiliary shaft is 10 m in net diameter and 1 503.9 m in depth.Since its sinking platform adopted 10-rope suspension ,its hoisting safety will be faced with risks like uneven stresses. In order to secure its hoisting safety ,a winch distributed control system was developed to en-sure the platform's synchronous running. A hydraulic automatic tension balance system was deployed at the suspension points. In this way ,the tension difference among each wire rope was eliminated ,avoi-ding dangers like concentrated wire rope stress ,winch overload. An online tension monitoring system was developed and applied for the wire ropes.So ,real-time monitoring of wire rope stress state was conducted ,achieving emergency operation like alarming and stopping when abnormal stresses oc-curred. These three technologies were successfully applied in the auxiliary shaft project of the Sishan-ling Iron Mine ,resulting in secured shaft sinking safety ,improving efficiency for sinking platform lift-ing and descending.

  14. Preparation and characterization of large diameter pitch based carbon fiber/ABS resin composites with high thermal conductivities%大直径沥青基炭纤维/ABS树脂高导热复合材料的制备与表征

    Institute of Scientific and Technical Information of China (English)

    易静; 袁观明; 李轩科; 杜鸿达; 董志军; 李保六; 林剑峰

    2015-01-01

    将大直径中间相沥青基石墨化纤维定向排列后与ABS(丙烯腈_苯乙烯_丁二烯共聚物)树脂通过热压成型,制备出单向炭纤维ABS树脂基复合材料。借助X射线衍射、扫描电子显微镜和偏光显微镜等手段对炭纤维及其树脂基复合材料的晶体结构、形貌和光学织构进行表征,并研究纤维石墨化温度及体积分数对其复合材料导热性能的影响。结果表明,复合材料沿炭纤维轴向和径向显示出差异;复合材料沿纤维轴向的室温热扩散系数随纤维石墨化温度和体积分数的增加而增大。%Parallel, stretched and evenly arranged mesophase pitch based graphitized carbon fibers with diameters of 50_53 μm were coated with different amounts of acrylonitrile butadiene styrene ( ABS) resin, and hot_pressed to produce carbon fiber/ABS resin composites. The morphology, optical texture and crystal structure of the carbon fibers and their composites were characterized by scanning electron microscopy, polarized light microscopy and X_ray diffraction. The influence of the graphitization temperature and fiber content on the thermal conductivity of the composites was investigated. The thermal diffusivity and thermal conductivity of the composites along both fiber axial and radial directions showed an obvious difference, owing to the high orientation of the graphite crystals along the axial direction of the carbon fibers. The thermal diffusivity of the composites along the carbon fiber axial direction increased both with the graphitization temperature and fiber content. The composite with 54 vol.% carbon fibers graphitized at 2 900 ℃ showed the highest thermal conductivity.

  15. Multi-diameter silicon nanowires: Fabrication, characterization, and modeling

    Science.gov (United States)

    Alagoz, Arif Sinan

    Nanotechnology is a rapidly expanding interdisciplinary field offering novel devices for broad range of applications. Quantum effects and surface to volume ratio of nanostructures are strongly size dependent, and redefine material properties at nanoscale. Silicon is one of the most promising materials for next generation nanostructured transistors, photonics devices, Li-ion batteries, photovoltaic solar cells, and thermoelectric energy generators. Since electrical, optical, and mechanical properties of nanostructures strongly depend on their shape, size, periodicity, and crystal structure; it is crucial to control these parameters in order to optimize device performance for targeted applications. This dissertation is intended to develop a low-cost, low-temperature, high-throughput, and large-area nanowire fabrication method that can produce well-ordered arrays of hierarchical single-crystal silicon nanowires at large scale by using nanosphere lithography and metal-assisted chemical etching. Nanowire morphology was characterized by using scanning electron microscope and optical properties of nanowire arrays were modeled with the help of finite-difference-time domain method. These novel multi-diameter silicon nanowire arrays have the potential applications in many fields including but not limited to next generation nanowire solar cells to field ionization gas sensors.

  16. Analysis of Gear Wheel-shaft Joint Characterized by Comparable Pitch Diameter and Mounting Diameter

    Directory of Open Access Journals (Sweden)

    J. Ryś

    2003-01-01

    Full Text Available This paper presents the design procedure for a gear wheel-shaft direct frictional joint. The small difference between the operating pitch diameter of the gear and the mounting diameter of the frictional joint is the key feature of the connection. The contact surface of the frictional joint must be placed outside the bottom land of the gear, and the geometry of the joint is limited to the specific type of solutions.The strength analysis is based on the relation between the torque and statistical load intensity of the gear transmission. Several dimensionless parameters are introduced to simplify the calculations. Stress-strain verifying analysis with respect to combined loading, the condition of appropriate load-carrying capacity of the frictional joint and the fatigue strength of the shaft are applied to obtain the relations between the dimensions of the joint and other parameters. The final engineering solution may then be suggested. The approach is illustrated by a numerical example.The proposed procedure can be useful in design projects for small, high-powered modern reducers and new-generation geared motors, in particular when manufactured in various series of types.

  17. Metallic beryllium-7 target of small diameter

    CERN Document Server

    Zyuzin, A Yu; Vincent, J S; Buckley, K R; Bateman, N P; Snover, K A; Csandjan, J M; Steiger, T D; Adelberger, E G; Swanson, H E

    1999-01-01

    The stellar sup 7 Be(p, gamma) sup 8 B reaction rate has the largest uncertainty among all nuclear reaction rates in the standard solar model. However, the solar neutrino flux predicted for the majority of proposed and existing solar neutrino detectors is directly dependent on the rate of sup 7 Be(p, gamma) sup 8 B reaction. The existing solar neutrino detectors measure rate of sup 8 B decay neutrinos that is too low. This constitutes largely the solar neutrino problem. Existing measurements of the sup 7 Be(p, gamma) sup 8 B reaction rate disagree with one another, indicating the need for more precise experiments. To provide the required targets a new procedure for sup 7 Be production, separation and target manufacturing has been developed. First, a lithium target has been designed for sup 7 Be production at TRIUMF's 13 MeV cyclotron. The lithium target has been extensively tested at 50 mu A proton beam current yielding 8.1 MBq/mu A h of sup 7 Be. An adsorption filtration technique has been developed for sup ...

  18. Effect of Adsorbent Diameter on the Performance of Adsorption Refrigeration

    Institute of Scientific and Technical Information of China (English)

    黄宏宇; 何兆红; 袁浩然; 小林敬幸; 赵丹丹; 窪田光宏; 郭华芳

    2014-01-01

    Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can af-fect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.

  19. On super edge-graceful trees of diameter four

    CERN Document Server

    Krop, E; Raridan, C

    2011-01-01

    In "On the super edge graceful trees of even orders," Chung, Lee, Gao, and Schaffer posed the following problem: Characterize trees of diameter 4 which are super edge-graceful. In this paper, we provide super edge-graceful labelings for all caterpillars and even size lobsters of diameter 4 which permit such labelings. We also provide super edge-graceful labelings for several families of odd size lobsters of diameter 4.

  20. Preparation of large monodisperse vesicles.

    Directory of Open Access Journals (Sweden)

    Ting F Zhu

    Full Text Available Preparation of monodisperse vesicles is important both for research purposes and for practical applications. While the extrusion of vesicles through small pores (approximately 100 nm in diameter results in relatively uniform populations of vesicles, extrusion to larger sizes results in very heterogeneous populations of vesicles. Here we report a simple method for preparing large monodisperse multilamellar vesicles through a combination of extrusion and large-pore dialysis. For example, extrusion of polydisperse vesicles through 5-microm-diameter pores eliminates vesicles larger than 5 microm in diameter. Dialysis of extruded vesicles against 3-microm-pore-size polycarbonate membranes eliminates vesicles smaller than 3 microm in diameter, leaving behind a population of monodisperse vesicles with a mean diameter of approximately 4 microm. The simplicity of this method makes it an effective tool for laboratory vesicle preparation with potential applications in preparing large monodisperse liposomes for drug delivery.

  1. k-Diameter of Circulant Graph with Degree 3

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-di; LI Man-li

    2005-01-01

    Parameters k-distance and k-diameter are extension of the distance and the diameter in graph theory. In this paper, the k-distance dk (x,y) between the any vertices x andy is first obtained in a connected circulant graph G with order n (n is even) and degree 3 by removing some vertices from the neighbour set of the x. Then, the k-diameters of the connected circulant graphs with order n and degree 3 are given by using the k-diameter dk (x, y).

  2. A 24mm diameter fibre positioner for spectroscopic surveys

    Science.gov (United States)

    Hörler, Philipp; Kronig, Luzius; Kneib, Jean-Paul; Bleuler, Hannes; Bouri, Mohamed

    2016-07-01

    One of the big research topics in modern cosmology is the mystery of dark Energy. To unveil the secret, cosmologists want to measure precisely the evolution of large scale structures in the universe. One way of doing so is to measure the 3D location of a high number of galaxies. By measuring the redshift of a galaxy, it is possible to find its distance. In order to measure a high number of galaxies in a practical amount of time, we need to observe multiple objects in parallel. Instead of a spectrograph, thousands of optical fibres are placed in the focal plane of a telescope. They will transmit the light of many objects to a spectrograph. Each fibre has to be positioned to several μm precision in the focal plane of a telescope for each exposure. Each fibre is positioned by a 2-axis fibre positioner. In this paper such a fibre positioner with 24-mm diameter is presented. It is driven by two brushless DC motors in combination with a backlash free gearbox. The positioner has an optimal central fibre path and improved angular alignment. The fibre runs through the centre of the positioner and is only bent at the top to reach its target position. In this way, the flexion and torsion of the fibre are minimal. In addition to the high positioning accuracy, the design is optimized to allow a minimal tilt error of the fibre. This is demonstrated using a novel optical tilt measurement system.

  3. Correlation Development for Sauter Mean Diameter of Rotary Atomizer

    Directory of Open Access Journals (Sweden)

    Murali.K

    2016-08-01

    Full Text Available Atomizers are of many types, among that simplex and duplex types of atomizers are used and recognized often as fuel injectors in aircrafts. Types of atomizers and features are read. Among many types of atomizer, rotary type of atomizer is selected due to its naked evident like easy retrofit to existing spreading system , able to handle large quantities, feed is possible, better economy, high peripheral speed and spread of droplets, uniform liquid feed rate, uniform distribution of feed, higher level of atomization etc., The rotary atomizer specifications and its features are listed, the droplets of rotary atomizer are visualized and readings are taken from experimental methods, such as Laser visualization method .After the droplets data alignment, the (SMD Sauter Mean Diameter is to be taken in and considered, SMD means it is a average particle (droplet size of a given particles, and it is further explained with its given relation. By SMD’s given equated form it is used to compare data between rotary atomizer particles and given particle size. By SMD it is simplified further and used to create a co-relation between SMD and rotary atomizer. The rotary atomizer data values are taken through out with the SMD to find and form a co-related derived pattern for ROTARY ATOMIZE

  4. More bounds on the diameters of convex polytopes

    CERN Document Server

    Bremner, David; Hua, William; Schewe, Lars

    2009-01-01

    Finding a good bound on the maximal edge diameter $\\Delta(d,n)$ of a polytope in terms of its dimension $d$ and the number of its facets $n$ is one of the basic open questions in polytope theory \\cite{BG}. Although some bounds are known, the behaviour of the function $\\Delta(d,n)$ is largely unknown. The Hirsch conjecture, formulated in 1957 and reported in \\cite{GD}, states that $\\Delta(d,n)$ is linear in $n$ and $d$: $\\Delta(d,n) \\leq n-d$. The conjecture is known to hold in small dimensions, i.e., for $d \\leq 3$ \\cite{VK}, along with other specific pairs of $d$ and $n$ (Table \\ref{before}). However, the asymptotic behaviour of $\\Delta(d,n)$ is not well understood: the best upper bound -- due to Kalai and Kleitman -- is quasi-polynomial \\cite{GKDK}. In this article we will show that $\\Delta(4,12)=7$ and present strong evidence for $\\Delta(5,12)=\\Delta(6,13)=7$. The first of these new values is of particular interest since it indicates that the Hirsch bound is not sharp in dimension 4.

  5. Mean particle diameters: from statistical definition to physical understanding

    NARCIS (Netherlands)

    Alderliesten, M.

    2008-01-01

    Mean particle diameters are important for the science of particulate systems. This thesis deals with a definition system for these mean diameters, called Moment-Ratio (M-R) definition system, and provides a general statistical and physical basis. Also, the current DIN/ISO definition system is discus

  6. Effect of flow rate on diameter of electrospun nanoporous fibers

    Directory of Open Access Journals (Sweden)

    Tang Xiao-Peng

    2014-01-01

    Full Text Available The effect of flow rate on the diameter of the charged jet in the electrospinning process is studied theoretically. The obtained theoretical results offer in-depth physical understanding and mechanism of nanoporous fibers. It also reveals that the morphology and diameter of nanoporous microspheres can be controlled by the flow rate.

  7. Reliable Diameter Control of Carbon Nanotube Nanobundles Using Withdrawal Velocity

    Science.gov (United States)

    Shin, Jung Hwal; Kim, Kanghyun; An, Taechang; Choi, WooSeok; Lim, Geunbae

    2016-09-01

    Carbon nanotube (CNT) nanobundles are widely used in nanoscale imaging, fabrication, and electrochemical and biological sensing. The diameter of CNT nanobundles should be controlled precisely, because it is an important factor in determining electrode performance. Here, we fabricated CNT nanobundles on tungsten tips using dielectrophoresis (DEP) force and controlled their diameters by varying the withdrawal velocity of the tungsten tips. Withdrawal velocity pulling away from the liquid-air interface could be an important, reliable parameter to control the diameter of CNT nanobundles. The withdrawal velocity was controlled automatically and precisely with a one-dimensional motorized stage. The effect of the withdrawal velocity on the diameter of CNT nanobundles was analyzed theoretically and compared with the experimental results. Based on the attachment efficiency, the withdrawal velocity is inversely proportional to the diameter of the CNT nanobundles; this has been demonstrated experimentally. Control of the withdrawal velocity will play an important role in fabricating CNT nanobundles using DEP phenomena.

  8. Heritability of retinal vessel diameters and blood pressure

    DEFF Research Database (Denmark)

    Taarnhøj, Nina C B B; Larsen, Michael; Sander, Birgit

    2006-01-01

    PURPOSE: To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics. METHODS: In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs......%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm...... and blood glucose, variations in retinal blood vessel diameters and blood pressure were predominantly attributable to genetic effects. A genetic influence may have a role in individual susceptibility to hypertension and other vascular diseases. The results suggest that retinal vessel diameters...

  9. Superresolution measurement of nanofiber diameter by modes beating

    Science.gov (United States)

    Fenton, E. F.; Solano, P.; Hoffman, J. E.; Orozco, L. A.; Rolston, S. L.; Fatemi, F. K.

    2016-05-01

    Nanofibers are becoming an important tool in quantum information technologies for coupling photonics systems to atomic systems. Nondestructive techniques for characterizing these nanofibers prior to integration into an apparatus are desirable. In this work, we probe the light propagating in a fused silica optical nanofiber (750-nm-diameter) by coupling it evanescently to a 6- μm-diameter microfiber that is scanned along the nanofiber length. This technique is capable of observing all possible beat lengths among different propagating modes. The beat lengths are strongly dependent on the nanofiber diameter and refractive index of the fiber. The steep dependence has enabled measurements of the fiber diameter with sub-Angstrom sensitivity. The diameter extracted from the beat length measurements agrees with a measurement made using scanning electron microscopy. Work supported by NSF.

  10. Towards stellar effective temperatures and diameters at one per cent accuracy for future surveys

    CERN Document Server

    Casagrande, L; Glass, I S; Laney, D; Aguirre, V Silva; Datson, J; Andersen, J; Nordström, B; Holmberg, J; Flynn, C; Asplund, M

    2014-01-01

    The apparent size of stars is a crucial benchmark for fundamental stellar properties such as effective temperatures, radii and surface gravities. While interferometric measurements of stellar angular diameters are the most direct method to gauge these, they are still limited to relatively nearby and bright stars, which are saturated in most of the modern photometric surveys. This dichotomy prevents us from safely extending well calibrated relations to the faint stars targeted in large spectroscopic and photometric surveys. Here, we alleviate this obstacle by presenting SAAO near-infrared JHK observations of 55 stars: 16 of them have interferometric angular diameters, and the rest are in common with the 2MASS (unsaturated) dataset, allowing us to tie the effective temperatures and angular diameters derived via the Infrared Flux Method to the interferometric scale. We extend the test to recent interferometric measurements of unsaturated 2MASS stars, including giants, and the metal-poor benchmark target HD122563...

  11. Influence of focal spot on characteristics of very small diameter radiosurgical beams.

    Science.gov (United States)

    Sham, Edwin; Seuntjens, Jan; Devic, Slobodan; Podgorsak, Ervin B

    2008-07-01

    Percentage depth dose (PDD) distributions and beam profiles of very small diameter (1.5-5 mm) megavoltage radiosurgical beams calculated with Monte Carlo (MC) technique critically depend on the diameter of the circular focal spot used in the simulation: The smaller is the field diameter, the larger is the effect. Thus, in simulations of radiosurgical fields that have diameters of the order of the focal spot size, an accurate focal spot geometry should be used. We used a simplified moving slit technique in conjunction with a diode detector for evaluation of the focal spot size and shape of a megavoltage 6 MV linac as well as for determination of the equivalent focal spot diameter of the linac for use in MC simulations. The measured total diode signal contains three components: A direct focal spot signal, a background signal, and an extra-focal radiation signal. A single profile scan of the focal spot signal is Gaussian like in shape, and its full width at half maximum is used to define the focal spot dimension for this scan. The focal spot of our 6 MV linac is approximated with a Gaussian circle, and when the geometry of the effective focal spot circle is used in MC simulations, the agreement between MC-calculated and measured PDD distributions as well as beam profiles is good even for radiosurgical fields as small as 1.5 mm in diameter. Our results also confirm that matching the penumbral areas of accurately measured large-field beam profiles to the same areas of the MC-calculated beam profiles reliably leads to a realistic effective focal spot size for use in MC simulations of very small diameter beams.

  12. Variations of fine root diameter with root order in Manchurian ash and Dahurian larch plantations

    Institute of Scientific and Technical Information of China (English)

    WANG Xiangrong; WANG Zhengquan; HAN Youzhi; GU Jiacun; GUO Dali; MEI Li

    2007-01-01

    .gmelinii.The average coefficient of variation in first-order roots was less than 10%,second-and third-order was 10-20%,and fourth-and fifth-order was 20-30%.Thus,variation in root diameter also increased with the ascending root order.These results suggest that "fine roots",which are traditionally defined as an arbitrary diameter class (i.e.,<2 mm in diameter) may be too large a size class when compared with the finest roots.The finest roots have much shorter lifespan than larger diameter roots;however,the larger roots are still considered a component of the fine root system.Differences in the lifespan between root diameter and root order affect estimates of root turnover.Therefore,based on this study,it has been concluded that both diameter and branch order should be considered in the estimation of root lifespan and turnover.

  13. Association between axial length and horizontal and vertical globe diameters.

    Science.gov (United States)

    Jonas, Jost B; Ohno-Matsui, Kyoko; Holbach, Leonard; Panda-Jonas, Songhomitra

    2017-02-01

    To assess relationships between axial length and the horizontal and vertical globe diameters. The study consisted of enucleated human eyes. The horizontal, vertical, and sagittal diameters were measured. The study included 135 globes removed because of malignant uveal melanoma (111 globes) or end-stage painful glaucoma (n = 24 eyes). Mean axial, horizontal, and vertical diameters were 24.6 ± 2.6 mm (range: 20-35 mm), 23.7 ± 1.4 mm (range: 21-29 mm) and 23.7 ± 1.4 mm (range: 20-29 mm) respectively. The horizontal diameter and vertical diameter did not differ significantly (P = 0.92), while both were significantly (P globe diameter (P globe diameter = 0.84 × horizontal globe diameter + 3.69). The axial diameter was significantly (P 24 mm, the horizontal and vertical globe diameter increased by a lower amount of 0.19 and 0.21 mm, respectively, for each mm increase in axial diameter. Myopic enlargement of the globe beyond an axial length of 24 mm takes place predominantly in the sagittal axis, leading to a change in the globe form from a sphere to an elongated form. It fits with the notion that myopic elongation may occur by an elongation of the eye walls in regions close to the globe's equator.

  14. Diameter-dependent thermodynamic and elastic properties of metallic nanoparticles

    Science.gov (United States)

    Chandra, Jeewan; Kholiya, Kuldeep

    2015-04-01

    A simple theoretical model has been proposed to study the diameter-dependent properties of metallic nanoparticles, i.e. Ag, Au, Al, Ni, Pb, Cu and Fe. The diameter-dependent thermodynamic properties includes melting temperature, Debye temperature, evaporation temperature, melting enthapy and melting entropy. The model is also extended to study the diameter-dependent elastic properties including bulk modulus, Young's modulus and thermal expansion coefficient. On comparison with available experimental findings and other theoretical approaches, the results obtained with the present formulation depict a close agreement and demonstrate the validity of the method proposed in the present paper.

  15. Measurement of fetal biparietal diameter in owl monkeys (Aotus nancymaae).

    Science.gov (United States)

    Schuler, A Michele; Brady, Alan G; Tustin, George W; Parks, Virginia L; Morris, Chris G; Abee, Christian R

    2010-09-01

    Owl monkeys are New World primates frequently used in biomedical research. Despite the historical difficulty of breeding owl monkeys in captivity, several productive owl monkey breeding colonies exist currently. The animals in the colony we describe here are not timed-pregnant, and determination of gestational age is an important factor in prenatal care. Gestational age of human fetuses is often determined by using transabdominal measurements of fetal biparietal diameter. The purpose of this study was to correlate biparietal diameter measurements with gestational age in owl monkeys. We found that biparietal diameter can be used to accurately predict gestational age in owl monkeys.

  16. Tool electrode wear in electrical discharge of small diameter holes

    Directory of Open Access Journals (Sweden)

    Slătineanu Laurenţiu

    2017-01-01

    Full Text Available In the paper, the problem of obtaining small diameter holes in workpieces made of high speed steel by electrical discharge machining was formulated. A fulfil factorial experiment was designed and materialized, taking into consideration the tool electrode diameter, pulse on time and pulse off time as independent variables. The tool electrode wear was evaluated by means of the decrease of tool electrode mass and length. On the base of experimental results, power type empirical mathematical models were determined. One noticed the higher influence exerted by the too electrode diameter, whose increase determine the decrease of the tool electrode.

  17. Relationship of rolling bearing stiffness with diameter of roller

    Institute of Scientific and Technical Information of China (English)

    郭茂林; 王刚; 张瑞

    2002-01-01

    The theoretical formula of roller bearing stiffness is induced and compared with its empirical formula.In the experience formula the stiffness of roller bearing has nothing to do with the roller diameter. The relation-ship of roller bearing stiffness with roller diameter was studied using Hz contacting theory. It is concluded thatconclusion in experience formula is only approximate result of data processing under special conditions, and therelation between stiffness of roller bearing and roller diameter must be taken into consideration while designingor selecting roller bearings.

  18. Deep-Hole Inner Diameter Measuring System Based on Non-contact Capacitance Sensor

    Institute of Scientific and Technical Information of China (English)

    于永新; 张恒; 王宗超; 常以哲

    2010-01-01

    A precise aperture measuring system of small deep holes with capacitance sensors is presented. Based on the working principle of non-contact capacitance sensors, influence of the edge effect of gauge head is studied, and one capacitance sensor for measuring the aperture of the small blind holes or through holes is introduced. The system is composed of one positioning device, one aperture measuring capacitance sensor, one measuring circuit, and software. This system employs visual CCD and two-dimensional mic...

  19. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2003-06-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and attaching a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service (which results in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1-Program Management was previously completed. Two reports, one describing the program management plan and the other consisting of the technology assessment, were submitted to the DOE COR in the first quarter. Task 2-Establishment of Detailed Design Specifications and Task 3-Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves are now well underway. First-quarter activities included conducting detailed analyses to determine the capabilities of coiled-tubing locomotion for entering and repairing gas mains and the first design iteration of the joint-sealing sleeve. The maximum horizontal reach of coiled tubing inside a pipeline before buckling prevents further access was calculated for a wide range of coiled-tubing string designs and pipe environments. Work conducted in the second quarter consisted of: (1) selecting a preferred pan/zoom/tilt camera; (2) initiating design of the digital control electronics and switching power supply for the control and operation of the in-pipe robotic modules; (3) continuing design of the repair sleeve and (4) initial testing of the wall-cleaning device. Activities in the third quarter included: (1) development of the system's pan/zoom/tilt camera control electronics and operating software, and implementing these in the surface and downhole modules and (2) further testing of the wall-cleaning elements used to clean the inside of the bell and spigot joints. Most recently, fourth quarter developments were centered on designing and testing the pipe-wall cleaning device including the selection of the drive motor and its control electronics. In addition, efforts were also focused on the design of the repair sleeve. Details of these activities are described in the body of the report along with a summary of events scheduled for the next quarter.

  20. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2003-01-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and attaching a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service (which results in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1--Program Management was previously completed. Two reports, one describing the program management plan and the other consisting of the technology assessment, were submitted to the DOE COR in the first quarter. Task 2--Establishment of Detailed Design Specifications and Task 3--Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves are now well underway. First-quarter activities included conducting detailed analyses to determine the capabilities of coiled-tubing locomotion for entering and repairing gas mains and the first design iteration of the joint-sealing sleeve. The maximum horizontal reach of coiled tubing inside a pipeline before buckling prevents further access was calculated for a wide range of coiled-tubing string designs and pipe environments. Work conducted in the second quarter consisted of: (1) selecting a preferred pan/zoom/tilt camera; (2) initiating design of the digital control electronics and switching power supply for the control and operation of the in-pipe robotic modules; (3) continuing design of the repair sleeve and (4) initial testing of the wall-cleaning device. Most recently, activities in the third quarter included: (1) development of the system's pan/zoom/tilt camera control electronics and operating software, and implementing these in the surface and downhole modules and (2) further testing of the wall-cleaning elements used to clean the inside of the bell and spigot joints. Details of these activities are described in the body of the report along with a summary of events scheduled for the fourth quarter.

  1. SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kiran M. Kothari; Gerard T. Pittard

    2005-07-01

    Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. Bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs with the pipe in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, minimize excavation, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of old cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct safe repair operations on live mains.

  2. Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

    Directory of Open Access Journals (Sweden)

    Wang Duanduan

    2015-01-01

    Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

  3. Soil-Structure Interaction For Nonslender, Large-Diameter Offshore Monopiles

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal

    , the modern offshore wind turbine offers competitive production prices compared to other sources of renewable energy. Therefore, it is a key technology in breaking the dependence on fossil fuels and in achieving the energy and climate goals of the future. For offshore wind turbines, the costs of foundation...

  4. Research on deformation characteristics of JCOE forming in large diameter welding pipe

    Institute of Scientific and Technical Information of China (English)

    Li-Feng Fan; Jia-Xin Yan; Ying Gao; Jian-Bin Yun

    2016-01-01

    In the present work,the JCOE forming is investigated using the finite element (FE) method.A twodimensional FE model is established for the plane strain condition by FE code ABAQUS,and the FE model is validated by experiments.The aim of this research is to investigate forming quality states in the JCOE forming process;in particular,the effects of technological parameters on forming quality are evaluated.Taking the JCOE forming process of X80 steel Φ1 219 mm × 22 mm× 12 000 mmwelding pipe for instance,the deformation characteristics of JCOE forming are analyzed,in which the geometry of the formed pipe,residual stress distributions and effects of process parameters on JCOE forming quality can be obtained.Thus,the presented results of this research provide an effective approach to improve welding pipe forming quality.

  5. Sensitivity Analysis of large Rotor Diameter on Offshore Wind Turbines with Suction Foundation

    OpenAIRE

    Thomassen, Øystein Sunde

    2014-01-01

    This thesis has an objective aimed at understanding the sensitivity of the support structure for an offshore wind turbine with bucket foundation as the turbines get larger. The focus has been on the response and forces on turbine blades in turbulent wind and how these responses propagates to the foundation of the structure. Special attention is given to the second global bending modes of the support structure. The response in the connection between the bucket and transition piece is simulated...

  6. Munitions having an insensitive detonator system for initiating large failure diameter explosives

    Science.gov (United States)

    Perry, III, William Leroy

    2015-08-04

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  7. Steady-state modeling of large-diameter crystal growth using baffles

    Science.gov (United States)

    Sahai, Vivek; Williamson, John W.; Overfelt, Tony

    1991-12-01

    Buoyancy driven flow in the crystal melt is one of the leading causes of segregation. Natural convection arises from the presence of thermal and/or solutal gradients in the melt and it is not possible to completely eliminate the convection even in the low gravity environment of space. This paper reports the results of computational modeling research that is being done in preparation for space-based experiments. The commercial finite element code FIDAP was used to simulate the steady convection of a gallium-doped germanium alloy in a Bridgman- Stockbarger furnace. In particular, the study examines the convection-suppressing benefits of inserting cylindrical baffles in the molten region to act as viscous dampers. These thin baffles are assumed to be inert and noncontaminating. The results from this study show the manner in which the streamlines, velocities, and temperature fields at various gravity levels are affected by the presence of baffles. The effects of changing both the number and position of the baffles are examined and the advantages and disadvantages of using baffles are considered.

  8. 76 FR 9608 - Certain Welded Large Diameter Line Pipe From Mexico

    Science.gov (United States)

    2011-02-18

    ... potential impact on the Commission's analysis of the Mexican industry's home market orientation, its capacity trends, and the presence of Mexican imports in the U.S. market. The Panel noted that the revised..., including its findings relating to the Mexican industry's home market orientation, its capacity trends,...

  9. Numerical analysis and simulation of Czochralski growth processes for large diameter silicon crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Numerical analysis and simulation have been an effective means to develop the advanced growth technology and to control the defects type, size and density for silicon crystals of 300 mm and beyond In the present paper, numerical analysis of the melt flow in the Czochralski (CZ) crystal growth configuration, the three dimensional (3D) modeling, the simulation of melt flow under the magnetic field, the inverse modeling and the time-dependent simulation are reviewed. Finally, comparison of numerical analysis with experimental measurements is discussed.

  10. Large-Diameter Sewer Rehabilitation Using a Spray-Applied Fiber-Reinforced Geopolymer Mortar

    Science.gov (United States)

    In order to assist the utilities in making well informed maintenance decisions, the U.S. Environmental Protection Agency (EPA) has developed an innovative technology demonstration program to evaluate technologies that have the potential to reduce costs and increase the effectiven...

  11. Experimental Investigation of Friction Effect on Liner Model Rolling Bearings for Large Diameter Thrust Bearing Design

    Directory of Open Access Journals (Sweden)

    S. Babu

    2012-12-01

    Full Text Available Studying friction coefficient has significant importance, especially when dealing with high load and temperature applications that have frequent starting and stopping points. Towards that, two sets of angular contact Linear Model Mockup Bearings (LMMB were designed and fabricated. This linear model assembly was made up of high precision, grounded raceways (AISI 4140 and commercially purchased balls (AISI 52100. The experimental studies were carried out by placing different number of balls between the raceways under different loads at dry lubricating condition. The static friction coefficients were measured using two different experiments: viz gravitation-based experiment and direct linear force measurement experiment. And Digital Image Correlation (DIC technique was used to find the stiffness of LMMB set.

  12. Improved collapse resistance of large diameter pipe for deepwater applications using a new impander technology

    Energy Technology Data Exchange (ETDEWEB)

    Reichel, Thilo; Pavlyk, Vitaliy; Beissel, Jochem [Eisenbau Kramer GmbH, Kreutztal-Kredenbach, (Germany); Kyriakides, Stelias; Jang, Wen-Yea [The University of Texas at Austin, Austin, TX, (United States)

    2010-07-01

    The UOE and JCO processes are usually used to design pipes larger than 16 inches. The reduced collapse pressures are caused by the cold forming process used during these processes. This paper investigated a new manufacturing process in which longitudinally welded pipe formed by the JCO process is finished by controlled compression using a new cold sizing press called the Impander. Various rings have been evaluated to measure the dimensional and mechanical properties performed by this new compression process. Dimensional measurements were measured using calipers, micrometers and later a custom scanning system. The results showed that the compression improved the circularity of the pipe. The mechanical properties were measured by bending residual stress tests and a custom numerical model BEPTICO was used for evaluating the collapse pressure. It is found that this new process reduces the residual stresses of the pipe and improves its straightness.

  13. X-ray emission and dynamics from large diameter superbubbles: The case of N 70 superbubble

    CERN Document Server

    Rodríguez-González, Ary; Rosado, Margarita; Esquivel, Alejandro; Reyes-Iturbide, Jorge; Toledo-Roy, J Claudio

    2011-01-01

    The morphology, dynamics and thermal X-ray emission of the superbubble N70 is studied by means of 3D hydrodynamical simulations, carried out with the {\\sc{yguaz\\'u-a}} code. We have considered different scenarios: the superbubble being the product of a single supernova remnant, of the stellar winds from an OB association, or the result of the joint action of stellar winds and a supernova event. Our results show that, in spite that all scenarios produce bubbles with the observed physical size, only those where the bubble is driven by stellar winds and a SN event are successful to explain the general morphology, dynamics and the X-ray luminosity of N70. Our models predict temperatures in excess of $10^8 \\mathrm{K}$ at the interior of the superbubble, however the density is too low and the emission in thermal X-ray above $2 \\mathrm{keV}$ is too faint to be detected.

  14. Hollow-core tapered coupler for large inner diameter hollow-core optical fibers

    Institute of Scientific and Technical Information of China (English)

    Guiyao Zhou(周桂耀); Zhiyun Hou(侯峙云); Lantian Hou(侯蓝田); Jigang Liu(刘继刚)

    2003-01-01

    A novel hollow-core tapered coupler has been theoretically designed and fabricated by fiber drawing machine. The coupler's inner wall is coated with a polycrystalline GeO2 film. The coupling loss of hollow-core tapered coupler is about 0.2 dB. Hollow-core tapered coupler reduces the transmission loss of hollow-core optical fiber (HCOF) by 0.5 dB/m, therefore the coupler is suitable for coupling high power CO2 laser in industrial application.

  15. Growth and Characterization of Large Diameter CdNzTe Crystals

    Science.gov (United States)

    2006-05-01

    not damaged during the annealing process. A future outlook based on the results of a longer-term effort in CZT growth and substrate fabrication in... end of the crystallization process. This signal is collected by using a high precision digital multimeter equipped with 8 channels analog scanner. The...the program or manually from the controller front panel keypad), all warning and error messages, etc. The computer program was written in

  16. Stress analysis of a large diameter, heated pipeline in mountainous terrain

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo, Dario R.; Riccillo, Domingo; Curle, Ronald K. [TECHINT S.A. (Brazil)

    2003-07-01

    The primary goals of modern pipeline design and construction projects, are safety and low cost. High strength steels such as API-5L Gr. X70 reduce installed weights but translate into high D/t ratios. Modern manufacturing methods, used produce API grade pipes, increase yield strength with minimal changes to the ultimate tensile strength (UTS). The trend toward the use of high strength pipe reduces costs, but correspondingly increases D/t ratios. There are significant challenges in stress and rupture analysis to ensure stability under loading conditions that include static and transient pressures, high temperatures, dead weights, and seismic forces. (author)

  17. Radial deformation of single-walled carbon nanotubes on quartz substrates and the resultant anomalous diameter-dependent reaction selectivity

    Institute of Scientific and Technical Information of China (English)

    Juan Yang; Yu Liu; Daqi Zhang; Xiao Wang; Ruoming Li; Yan Li

    2015-01-01

    Owing to the unique conjugated structure, the chemical-reaction selectivity of single-walled carbon nanotubes (SWNTs) has attracted great attention. By utilizing the radial deformation of SWNTs caused by the strong interactions with the quartz lattice, we achieve an anomalous diameter-dependent reaction selectivity of quartz lattice-oriented SWNTs in treatment with iodine vapor; this is distinctly different from the widely reported and well accepted higher reaction activity in small-diameter tubes compared to large-diameter tubes. The radial deformation of SWNTs on quartz substrate is verified by detailed Raman spectroscopy and mappings in both G-band and radial breathing mode. Due to the strong interaction between SWNTs and the quartz lattice, large-diameter tubes present a larger degree of radial deformation and more delocalized partial electrons are distributed at certain sidewall sites with high local curvature. It is thus easier for the carbon--carbon bonds at these high-curvature sites on large-diameter tubes to break down during reaction. This anomalous reaction activity offers a novel approach for selective removal of small-band~aD large-diameter tubes.

  18. Porosity Assessment for Different Diameters of Coir Lignocellulosic Fibers

    Science.gov (United States)

    da Luz, Fernanda Santos; Paciornik, Sidnei; Monteiro, Sergio Neves; da Silva, Luiz Carlos; Tommasini, Flávio James; Candido, Verônica Scarpini

    2017-08-01

    The application of natural lignocellulosic fibers (LCFs) in engineering composites has increased interest in their properties and structural characteristics. In particular, the inherent porosity of an LCF markedly affects its density and the adhesion to polymer matrices. For the first time, both open and closed porosities of a natural LCF, for different diameter ranges, were assessed. Fibers extracted from the mesocarp of the coconut fruit were investigated by nondestructive methods of density measurements and x-ray microtomography (microCT). It was found that, for all diameter ranges, the closed porosity is significantly higher than the open porosity. The total porosity increases with diameter to around 60% for coir fibers with more than 503 μm in diameter. The amount and characteristics of these open and closed porosities were revealed by t test and Weibull statistics as well as by microCT.

  19. Heritability of retinal vessel diameters and blood pressure

    DEFF Research Database (Denmark)

    Taarnhøj, Nina C B B; Larsen, Michael; Sander, Birgit

    2006-01-01

    PURPOSE: To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics. METHODS: In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs......%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm...... for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values. CONCLUSIONS: In healthy young adults with normal blood pressure...

  20. Study of Linearly Polarized Light Measuring Fiber Diameter

    Energy Technology Data Exchange (ETDEWEB)

    Liang Hong, E-mail: lianghong@cuc.edu.cn [School of science, Communication University of China 100024 (China)

    2011-02-01

    The letter discusses a new way to measure fiber diameters, studies the theory of measuring fiber radius using this way, carries out numerical simulation based on this and provides experiment method as well.

  1. Eddy sensors for small diameter stainless steel tubes.

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Jack L.; Morales, Alfredo Martin; Grant, J. Brian; Korellis, Henry James; LaFord, Marianne Elizabeth; Van Blarigan, Benjamin; Andersen, Lisa E.

    2011-08-01

    The goal of this project was to develop non-destructive, minimally disruptive eddy sensors to inspect small diameter stainless steel metal tubes. Modifications to Sandia's Emphasis/EIGER code allowed for the modeling of eddy current bobbin sensors near or around 1/8-inch outer diameter stainless steel tubing. Modeling results indicated that an eddy sensor based on a single axial coil could effectively detect changes in the inner diameter of a stainless steel tubing. Based on the modeling results, sensor coils capable of detecting small changes in the inner diameter of a stainless steel tube were designed, built and tested. The observed sensor response agreed with the results of the modeling and with eddy sensor theory. A separate limited distribution SAND report is being issued demonstrating the application of this sensor.

  2. Pupil diameter reflects uncertainty in attentional selection during visual search

    Directory of Open Access Journals (Sweden)

    Joy J. Geng

    2015-08-01

    Full Text Available Pupil diameter has long been used as a metric of cognitive processing. However, recent advances suggest that the cognitive sources of change in pupil size may reflect LC-NE function and the calculation of unexpected uncertainty in decision processes (Aston-Jones & Cohen, 2005b; Yu & Dayan, 2005. In the current experiments, we explored the role of uncertainty in attentional selection on task-evoked changes in pupil diameter during visual search. We found that task-evoked changes in pupil diameter were related to uncertainty during attentional selection as measured by reaction time and performance accuracy (Experiments 1-2. Control analyses demonstrated that the results are unlikely to be due to error monitoring or response uncertainty. Our results suggest that pupil diameter can be used as an implicit metric of uncertainty in ongoing attentional selection requiring effortful control processes.

  3. Fracture behaviour and defect evaluation of larger diameter, HSLA steels, very high pressure linepipes

    Energy Technology Data Exchange (ETDEWEB)

    Demofonti, G.; Mannucci, G. [Centro Sviluppo materiali Via di Castel Romano, Rome (Italy); Barsanti, L.; Spinelli, C.M. [SNAM SPA, Milan (Italy); Hillenbrand, H.G. [Europipe GmbH Sornerstrasse, Ratengen (Germany)

    2000-07-01

    A joint venture research program by members of the European Union was conducted to examine the fracture behaviour of large diameter API X100 grade steel pipes at very high pressure (up to 150 bar). The impetus for this study has been the need to develop a larger diameter pipe to transport natural gas at high pressure for very long distances, thereby reducing transportation costs. The material examined in this study was the API X100 high strength low alloy steel grade pipe produced by Europipe for use in large diameter pipes. The current status of API X100 steel with respect to the combination of chemical composition, rolling variables and mechanical properties was presented. The ductile-brittle transition behaviour of the material was also examined in conjunction with the control of long shear propagation fracture and full scale crack propagation tests on lines operating at very high stress. The defect tolerance behaviour of the pipe was investigated with respect to axial surface defects and burst tests with water. The material showed full ductile fracture behaviour down to -20 degrees C. The toughness characteristics of the materials according to Charpy V energy tests was good enough to warrant the arrest of a long running shear fracture on a 56 inch diameter, at operating pressure over 12.6 MPa. 8 refs., 6 tabs., 7 figs.

  4. Is ultrasonographically detected nodule diameter concordant with pathological tumor size?

    Science.gov (United States)

    Bilginer, Muhammet Cuneyt; Ozdemir, Didem; Baser, Husniye; Dogan, Hayriye Tatli; Yalcin, Abdussamed; Ersoy, Reyhan; Cakir, Bekir

    2017-06-01

    We aimed to compare preoperative ultrasonographical and postoperative histopathological diameters of differentiated thyroid cancer (DTC) lesions and investigate possible factors that can predict the discordance between two measurements. Data of patients with histopathologically confirmed DTC were reviewed retrospectively. Nodules evaluated by preoperative US were matched with histopathologically examined nodules. Incidental tumors and nodules that can not be matched in US and histopathology reports were excluded. Preoperative US diameter and postoperative histopathological size were compared and percentage difference between two measurements was calculated for each lesion. There were 607 DTC foci in 562 patients. Mean US diameter was significantly higher than histopathological diameter (21.0 ± 15.6 mm vs 17.3 ± 13.6, p size in 444 (73.1%), equal in 15 (2.5%) and lower in 148 (24.4%) nodules. Marginal irregularity was observed in 253 (57%) lesions with US diameter > tumor size and 108 (73%) lesions with US diameter size (p = 0.010). Rate of nodules with peripheral halo was higher in lesions with US diameter > tumor size (30.6% vs 20.3%, p = 0.015). In nodules with US diameter > tumor size, percentage difference was lower in nodules with microcalcification (p = 0.020) and higher in cytologically benign nodules (p size, size in a considerable ratio of DTCs. It might be helpful to consider this discordance while deciding surgical extent in these patients. Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  5. Minimum Orders of Eulerian Oriented Digraphs with Given Diameter

    Institute of Scientific and Technical Information of China (English)

    Yoomi RHO; Byeong Moon KIM; Woonjae HWANG; Byung Chul SONG

    2014-01-01

    A digraph D is oriented if it does not contain 2-cycles. If an oriented digraph D has a directed eulerian path, it is an oriented eulerian digraph. In this paper, when an oriented eulerian digraph D has minimum out-degree 2 and a diameter d, we find the minimum order of D. In addition, when D is 2-regular with diameter 4m (m≥2), we classify the extremal cases.

  6. Effect of diameter of poly(lactic acid) fiber on the physical properties of poly(ɛ-caprolactone).

    Science.gov (United States)

    Ju, Dandan; Han, Lijing; Guo, Ziqi; Bian, Junjia; Li, Fan; Chen, Shan; Dong, Lisong

    2015-05-01

    Biodegradable polymer composites based on poly(ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA) fibers with diameters of 18, 26, 180 μm were prepared by melt compounding. The PLA fiber content in the composites was constant at 20% by weight. The effects of fibers with different diameters on the physical properties and enzymatic degradation of PCL were investigated. The morphological analysis indicated good interfacial adhesion between PCL and PLA fiber, which was beneficial to improve the physical properties of PCL. With increasing PLA fiber diameter, the complex viscosity and modulus of PCL were significantly increased, especially at low frequencies, indicating that the hindered effect of the fiber on the mobility of the PCL molecular chains was more obvious when PLA fiber diameter was thicker. However, as for the mechanical properties, the reinforcement was more obvious to PCL with the smaller PLA fiber diameter. This was because increasing efficient load transfer may be appeared due to the larger surface area and better interface bonding force of the fiber with thinner diameters. The enzymatic degradation of PCL was accelerated with the addition of large PLA fiber diameter of 26 and 180 μm, and hardly changed with the small PLA fiber diameter of 18 μm.

  7. Relationship between myelin sheath diameter and internodal length in axons of the anterior medullary velum of the adult rat.

    Science.gov (United States)

    Ibrahim, M; Butt, A M; Berry, M

    1995-11-01

    Relations between myelin sheath diameters and internodal lengths were measured in whole mounts of osmium stained intact anterior medullary velum (AMV) from glutaraldehyde perfused adult rats. The AMV is a sheet of CNS tissue which roofs the IVth ventricle and contains fascicles of myelinated fibres which arise mainly from the nucleus of the IVth cranial nerve. These fibers displayed a broad range of myelin sheath external diameters and internodal lengths, from 4 microns. Our results indicated that small and large calibre fibres may have different myelin sheath diameter-internodal length interrelations.

  8. Delivery of Megawatts High Energy Laser Pulse with Large Core Diameter Silica Fiber and Its Application in Dual-Wavelength Laser-Ablation Laser-Induced Breakdown Spectroscopy%用大芯径石英玻璃光纤传输兆瓦级高能激光脉冲及其在双波长LA-L IBS技术中的应用

    Institute of Scientific and Technical Information of China (English)

    周奇; 彭飞飞; 李润华; 陈钰琦; 杨雪娇

    2013-01-01

    为了解决单脉冲激光诱导击穿光谱(L IBS )技术在元素分析时空间分辨本领与分析灵敏度之间的矛盾,本文利用一台双波长输出的Nd∶YAG激光器开展了双波长激光剥离-激光诱导击穿光谱(LA-LIBS)技术的研究。其中532 nm的二倍频激光用于剥离样品;1064 nm的基频激光通过大芯径石英玻璃光纤传输并实现一定的延时后用于击穿被剥离的样品。两束激光采用正交几何配置以实现高空间分辨高灵敏的元素分析。实验研究了1064 nm激光到光纤的耦合、光纤输出后的准直以及再聚焦时的一些关键技术问题。研究并得出了四种不同光纤对激光能量的传输能力。选择利用芯径为800μm ,数值孔径为0.39、长50 m的石英玻璃光纤成功传输了15 mJ的调Q激光脉冲并实现了250 ns的延时。并在此基础上开展了铜合金样品的双波长LA-LIBS分析,实验验证了基于一台Nd∶YAG激光器开展双波长LA-LIBS研究的可行性。该技术只需要一台激光器就可以完成相应的光谱分析,具有系统结构简单,便于小型化等优点,适合对不同样品开展原位的高空间分辨高灵敏的元素显微分析。%To resolve the contradiction between spatial resolution and analysis sensitivity in single pulse laser-induced breakdown spectroscopy (LIBS) ,a study on dual-wavelength laser-ablation laser-induced breakdown spectroscopy (LA-LIBS) was carried out by using one Nd∶YAG laser which was capable of two laser beam outputs with different wavelengths ,where ,the second harmonic output ,532 nm laser beam ,was used as laser-ablation source ,and the fundamental output ,1 064 nm laser beam ,was delivered with a large core diameter silica fiber to realize nanoseconds time-delay and then used to breakdown the ablated sam-ples .Two laser beams were orthogonally arranged to realize element analysis with high spatial resolution and high sensitivity . Some key

  9. Highly efficient fiber-to-chip evanescent coupling based on subwavelength-diameter optical fibers

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Shen; Xinwan Li; Lijie Zhou; Zehua Hong; Xiaocao Yu; Ying Zhang; Jianping Chen

    2011-01-01

    @@ A novel, compact, and highly efficient fiber-to-chip evanescent coupling structure is proposed based on a subwavelength-diameter fiber.The coupling structure is characterized by a large misalignment tolerance and easy fabrication.The dependence of coupling efficiency on various parameters is calculated and analyzed.%A novel, compact, and highly efficient fiber-to-chip evanescent coupling structure is proposed based on a subwavelength-diameter fiber. The coupling structure is characterized by a large misalignment tolerance and easy fabrication. The dependence of coupling efficiency on various parameters is calculated and analyzed. The simulation results show that a coupling efficiency as high as 95% can be obtained within a coupling length of <4 μm.

  10. Failure Diameter of PBX 9502: Simulations with the SURFplus model

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-03

    SURFplus is a reactive burn model for high explosives aimed at modelling shock initiation and propagation of detonation waves. It utilizes the SURF model for the fast hot-spot reaction plus a slow reaction for the energy released by carbon clustering. A feature of the SURF model is that there is a partially decoupling between burn rate parameters and detonation wave properties. Previously, parameters for PBX 9502 that control shock ini- tiation had been calibrated to Pop plot data (distance-of-run to detonation as a function of shock pressure initiating the detonation). Here burn rate parameters for the high pres- sure regime are adjusted to t the failure diameter and the limiting detonation speed just above the failure diameter. Simulated results are shown for an uncon ned rate stick when the 9502 diameter is slightly above and slightly below the failure diameter. Just above the failure diameter, in the rest frame of the detonation wave, the front is sonic at the PBX/air interface. As a consequence, the lead shock in the neighborhood of the interface is supported by the detonation pressure in the interior of the explosive rather than the reaction immediately behind the front. In the interior, the sonic point occurs near the end of the fast hot-spot reaction. Consequently, the slow carbon clustering reaction can not a ect the failure diameter. Below the failure diameter, the radial extent of the detonation front decreases starting from the PBX/air interface. That is, the failure starts at the PBX boundary and propagates inward to the axis of the rate stick.

  11. The Primary Study of the Construction of Small Diameter Tissue-engineered Blood Vessel

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionToday, the blood vessel substitutes are in large demand for coronary and peripheral bypass procedures. Each year, more than 600,000 coronary artery bypass graft procedures are performed in the United States. There are some blood vessel substitutes including autografts, allografts and synthetic grafts that have been applied in vascular surgery in clinics. But their clinical implementations are prevented, especially for the <6mm in diameter grafts, because of their shortcomings such as inadequat...

  12. Hole diameters in pet bottles used for fruit fly capture

    Directory of Open Access Journals (Sweden)

    Maurico Paulo Batistella Pasini

    2015-05-01

    Full Text Available Two experiments were conducted during the period from 31 January to 6 March 2012 in Santa Maria, Rio Grande do Sul State, Brazil to determine the efficiency of different hole diameters in PET trap bottles on pests in guava and persimmon orchards. In a randomised block design in a factorial scheme, we assessed the average number adults of Anastrepha fraterculus, Ceratitis capitata (Diptera: Tephitidae and Zaprionus indianus (Diptera: Drosophilidae infruits thatemerged in two situations (in the plant and on the soil; we also assessed the number of captured adults in trap bottlesunder two conditions, different hole diameters and different days after placement of the attractive solution. Smaller diameter sizescaptured more A. fraterculus, C. capitata and Z. indianusadults. The 1.0 cm diameter was the most efficient hole size in reducing the adult emergence of Tephritidae to Z. indianus, whereas the smallest diameter hole sizes, 0.6 and 0.8 cm, showed the highest efficiencies in controlling adult emergence in persimmon fruit and guava fruit.

  13. Parametric Probability Distribution Functions for Axon Diameters of Corpus Callosum

    Directory of Open Access Journals (Sweden)

    Farshid eSepehrband

    2016-05-01

    Full Text Available Axon diameter is an important neuroanatomical characteristic of the nervous system that alters in the course of neurological disorders such as multiple sclerosis. Axon diameters vary, even within a fiber bundle, and are not normally distributed. An accurate distribution function is therefore beneficial, either to describe axon diameters that are obtained from a direct measurement technique (e.g., microscopy, or to infer them indirectly (e.g., using diffusion-weighted MRI. The gamma distribution is a common choice for this purpose (particularly for the inferential approach because it resembles the distribution profile of measured axon diameters which has been consistently shown to be non-negative and right-skewed. In this study we compared a wide range of parametric probability distribution functions against empirical data obtained from electron microscopy images. We observed that the gamma distribution fails to accurately describe the main characteristics of the axon diameter distribution, such as location and scale of the mode and the profile of distribution tails. We also found that the generalized extreme value distribution consistently fitted the measured distribution better than other distribution functions. This suggests that there may be distinct subpopulations of axons in the corpus callosum, each with their own distribution profiles. In addition, we observed that several other distributions outperformed the gamma distribution, yet had the same number of unknown parameters; these were the inverse Gaussian, log normal, log logistic and Birnbaum-Saunders distributions.

  14. Effect of rootstock diameter on apple saplings growth

    Directory of Open Access Journals (Sweden)

    VAHID AVDIU

    2014-03-01

    Full Text Available This research paper presents the results of a field trial with managed nursery trees including two apple cultivars Golden Reinders and Gala Galaxy on the rootstocks M9 and MM 106. In April 2011, the saplings (bench grafted in March 2011 were planted in the distance 100 cm x 35 cm in randomized block design in threecombinations of rootstock diameters (5-7 mm, 7-9 mm, 9-11 mm with threereplications (in total 60 saplings for each apple cultivar-rootstock and combinations in Mirovica, Kosovo. The following parameters were examined: growth, rootstock diameter, scion diameter, and stocks growth dynamic. The experimental design was a ANOVAs one-way analysing two different factors cultivars, rootstocks types and treatments (three combinations of rootstocks diameter. Significant differences were found in scion thickness and sapling growth among the three different combinations of rootstock diameter, dimensions and cultivars. Insignificant were differences were found within factors as cultivar, rootstock and their combinations Key words: Amino acids, Moringa oleifera, poultry manure.

  15. Memory, emotion, and pupil diameter: Repetition of natural scenes.

    Science.gov (United States)

    Bradley, Margaret M; Lang, Peter J

    2015-09-01

    Recent studies have suggested that pupil diameter, like the "old-new" ERP, may be a measure of memory. Because the amplitude of the old-new ERP is enhanced for items encoded in the context of repetitions that are distributed (spaced), compared to massed (contiguous), we investigated whether pupil diameter is similarly sensitive to repetition. Emotional and neutral pictures of natural scenes were viewed once or repeated with massed (contiguous) or distributed (spaced) repetition during incidental free viewing and then tested on an explicit recognition test. Although an old-new difference in pupil diameter was found during successful recognition, pupil diameter was not enhanced for distributed, compared to massed, repetitions during either recognition or initial free viewing. Moreover, whereas a significant old-new difference was found for erotic scenes that had been seen only once during encoding, this difference was absent when erotic scenes were repeated. Taken together, the data suggest that pupil diameter is not a straightforward index of prior occurrence for natural scenes. © 2015 Society for Psychophysiological Research.

  16. Assessment of the Effect of Blast Hole Diameter on the Number of Oversize Boulders Using ANN Model

    Science.gov (United States)

    Dhekne, Prakash; Pradhan, Manoj; Jade, Ravi Krishnarao

    2016-04-01

    Now-a-days, blasts are planned using large diameter blast holes. The loading density (kg/m) and subsequently the energy available for the breakage of the rockmass increase with the diameter. The in-hole velocity of detonation (VoD) of non-ideal explosive also boosts up with the increase in diameter till the optimum diameter is reached. The increase in the energy content and in-hole VoD cause a sizable effect on the rock fragmentation. The effect can be assessed by counting the number of oversize boulders. This paper explains as to how the technique of artificial neural network modeling was used to predict the number of oversize boulders resulting from ANFO and SME blasts with blast holes of different diameters. The results from ANFO blasts indicated that there was no significant variation in the number of oversize boulders with the diameter whereas a perceptible variation was noticed in case of SME blasts with the change in the diameter. The change in the number of oversize boulders in ANFO blasts was negligible because mean energy factor remained almost same even when the diameter of the blast holes was altered. The decrease in the number of oversize boulders in SME blasts was on account of increase in mean energy factor when the blast hole diameter was increased. The increase in the in-hole VoD due to increase in the diameter of the hole was not found to have an effect on the generation of oversize boulders as this increase was not substantial both in SME and ANFO blasts.

  17. Diameter of basalt columns derived from fracture mechanics bifurcation analysis.

    Science.gov (United States)

    Bahr, H-A; Hofmann, M; Weiss, H-J; Bahr, U; Fischer, G; Balke, H

    2009-05-01

    The diameter of columnar joints forming in cooling basalt and drying starch increases with decreasing growth rate. This observation can be reproduced with a linear-elastic three-dimensional fracture mechanics bifurcation analysis, which has been done for a periodic array of hexagonal columnar joints by considering a bifurcation mode compatible with observations on drying starch. In order to be applicable to basalt columns, the analysis has been carried out with simplified stationary temperature fields. The critical diameter differs from the one derived with a two-dimensional model by a mere factor of 1/2. By taking into account the latent heat released at the solidification front, the results agree fairly well with observed column diameters.

  18. On sub-determinants and the diameter of polyhedra

    CERN Document Server

    Bonifas, Nicolas; Eisenbrand, Friedrich; Hähnle, Nicolai; Niemeier, Martin

    2011-01-01

    We derive a new upper bound on the diameter of a polyhedron P = {x \\in R^n : Ax <= b}, where A \\in Z^{m\\timesn}. The bound is polynomial in n and the largest absolute value of a sub-determinant of A, denoted by \\Delta. More precisely, we show that the diameter of P is bounded by O(\\Delta^2 n^4 log n\\Delta). If P is bounded, then we show that the diameter of P is at most O(\\Delta^2 n^3.5 log n\\Delta). For the special case in which A is a totally unimodular matrix, the bounds are O(n^4 log n) and O(n^3.5 log n) respectively. This improves over the previous best bound of O(m^16 n^3 (log mn)^3) due to Dyer and Frieze.

  19. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

    Zhang, Hui; Dyrby, Tim B; Alexander, Daniel C

    2011-01-01

    tissue than measures derived from diffusion tensor imaging. Most existing techniques for axon diameter mapping assume a single axon orientation in the tissue model, which limits their application to only the most coherently oriented brain white matter, such as the corpus callosum, where the single...... orientation assumption is a reasonable one. However, fiber crossings and other complex configurations are widespread in the brain. In such areas, the existing techniques will fail to provide useful axon diameter indices for any of the individual fiber populations. We propose a novel crossing fiber tissue...... of the technique by establishing reasonable axon diameter indices in the crossing region at the interface of the cingulum and the corpus callosum....

  20. The angular diameter and distance of the Cepheid Zeta Geminorum

    CERN Document Server

    Kervella, P; Perrin, G; Schöller, M; Traub, W A; Lacasse, M D

    2001-01-01

    Cepheids are the primary distance indicators for extragalactic astronomy and therefore are of very high astrophysical interest. Unfortunately, they are rare stars, situated very far from Earth.Though they are supergiants, their typical angular diameter is only a few milliarcseconds, making them very challenging targets even for long-baseline interferometers. We report observations that were obtained in the K prime band (2-2.3 microns), on the Cepheid Zeta Geminorum with the FLUOR beam combiner, installed at the IOTA interferometer. The mean uniform disk angular diameter was measured to be 1.64 +0.14 -0.16 mas. Pulsational variations are not detected at a significant statistical level, but future observations with longer baselines should allow a much better estimation of their amplitude. The distance to Zeta Gem is evaluated using Baade-Wesselink diameter determinations, giving a distance of 502 +/- 88 pc.

  1. Reduced arterial diameter during static exercise in humans

    DEFF Research Database (Denmark)

    Olesen, H L; Mitchell, J H; Friedman, D B

    1995-01-01

    of another limb. Static exercise increased heart rate and mean arterial pressure, which were largest during one-leg knee extension. After exercise heart rate and mean arterial pressure returned to the resting level. No changes were recorded in arterial carbon dioxide tension, and the rate of perceived......In eight subjects luminal diameter of the resting limb radial and dorsalis pedis arteries was determined by high-resolution ultrasound (20 MHz). This measurement was followed during rest and during 2 min of static handgrip or of one-leg knee extension at 30% of maximal voluntary contraction...... exertion was approximately 15 units after both types of exercise. The dorsalis pedis arterial diameter was 1.50 +/- 0.20 mm (mean and SE) and the radial AD 2.45 +/- 0.12 mm. During both types of contractions the luminal diameters decreased approximately 3.5% within the first 30 s (P

  2. Directional Solidification and Convection in Small Diameter Crucibles

    Science.gov (United States)

    Chen, J.; Sung, P. K.; Tewari, S. N.; Poirier, D. R.; DeGroh, H. C., III

    2003-01-01

    Pb-2.2 wt% Sb alloy was directionally solidified in 1, 2, 3 and 7 mm diameter crucibles. Pb-Sb alloy presents a solutally unstable case. Under plane-front conditions, the resulting macrosegregation along the solidified length indicates that convection persists even in the 1 mm diameter crucible. Al-2 wt% Cu alloy was directionally solidified because this alloy was expected to be stable with respect to convection. Nevertheless, the resulting macrosegregation pattern and the microstructure in solidified examples indicated the presence of convection. Simulations performed for both alloys show that convection persists for crucibles as small as 0.6 mm of diameter. For the solutally stable alloy, Al-2 wt% Cu, the simulations indicate that the convection arises from a lateral temperature gradient.

  3. Application of direct tracking method for measuring electrospun nanofiber diameter

    Directory of Open Access Journals (Sweden)

    M. Ziabari

    2009-03-01

    Full Text Available In this paper, direct tracking method as an image analysis based technique for measuring electrospun nanofiber diameter has been presented and compared with distance transform method. Samples with known characteristics generated using a simulation scheme known as µ-randomness were employed to evaluate the accuracy of the method. Electrospun webs of polyvinyl alcohol (PVA were also used to verify the applicability of the method on real samples. Since direct tracking as well as distance transform require binary input images, micrographs of the electrospun webs obtained from Scanning Electron Microscopy (SEM were first converted to black and white using local thresholding. Direct tracking resulted in more accurate estimations of fiber diameter for simulated images as well as electrospun webs suggesting the usefulness of the method for electrospun nanofiber diameter measurement.

  4. Effect of tube-electrode inner diameter on electrochemical discharge machining of nickel-based superalloy

    Directory of Open Access Journals (Sweden)

    Zhang Yan

    2016-08-01

    Full Text Available Nickel-based superalloys are widely employed in modern aircraft engines because of their excellent material characteristics, particularly in the fabrication of film cooling holes. However, the high machining requirement of a large number of film cooling holes can be extremely challenging. The hybrid machining technique of tube electrode high-speed electrochemical discharge drilling (TEHECDD has been considered as a promising method for the production of film cooling holes. Compared with any single machining process, this hybrid technique requires the removal of more complex machining by-products, including debris produced in the electrical discharge machining process and hydroxide and bubbles generated in the electrochemical machining process. These by-products significantly affect the machining efficiency and surface quality of the machined products. In this study, tube electrodes in different inner diameters are designed and fabricated, and the effects of inner diameter on the machining efficiency and surface quality of TEHECDD are investigated. The results show that larger inner diameters could effectively improve the flushing condition and facilitate the removal of machining by-products. Therefore, higher material removal efficiency, surface quality, and electrode wear rate could be achieved by increasing the inner diameter of the tube electrode.

  5. Effect of tube-electrode inner diameter on electrochemical discharge machining of nickel-based superalloy

    Institute of Scientific and Technical Information of China (English)

    Zhang Yan; Xu Zhengyang; Xing Jun; Zhu Di

    2016-01-01

    Nickel-based superalloys are widely employed in modern aircraft engines because of their excellent material characteristics, particularly in the fabrication of film cooling holes. How-ever, the high machining requirement of a large number of film cooling holes can be extremely chal-lenging. The hybrid machining technique of tube electrode high-speed electrochemical discharge drilling (TEHECDD) has been considered as a promising method for the production of film cooling holes. Compared with any single machining process, this hybrid technique requires the removal of more complex machining by-products, including debris produced in the electrical discharge machin-ing process and hydroxide and bubbles generated in the electrochemical machining process. These by-products significantly affect the machining efficiency and surface quality of the machined prod-ucts. In this study, tube electrodes in different inner diameters are designed and fabricated, and the effects of inner diameter on the machining efficiency and surface quality of TEHECDD are inves-tigated. The results show that larger inner diameters could effectively improve the flushing condi-tion and facilitate the removal of machining by-products. Therefore, higher material removal efficiency, surface quality, and electrode wear rate could be achieved by increasing the inner diam-eter of the tube electrode.

  6. Optical coating uniformity of 200mm (8") diameter precut wafers

    Science.gov (United States)

    Burt, Travis C.; Fisher, Mark; Brown, Dean; Troiani, David

    2017-02-01

    Automated spectroscopic profiling (mapping) of a 200 mm diameter near infrared high reflector (centered at 1064 nm) are presented. Spatial resolution at 5 mm or less was achieved using a 5 mm × 1.5 mm monochromatic beam. Reflection changes of 1.0% across the wafer diameter were observed under s-polarized and p- polarized conditions. Redundancy was established for each chord by re-measuring the center of the wafer and reproducibility of approximately platform for angles of incidence in the range 5°stream processing.

  7. On the diameter of the Kronecker product graph

    CERN Document Server

    Hu, Fu-Tao

    2012-01-01

    Let $G_1$ and $G_2$ be two undirected nontrivial graphs. The Kronecker product of $G_1$ and $G_2$ denoted by $G_1\\otimes G_2$ with vertex set $V(G_1)\\times V(G_2)$, two vertices $x_1x_2$ and $y_1y_2$ are adjacent if and only if $(x_1,y_1)\\in E(G_1)$ and $(x_2,y_2)\\in E(G_2)$. This paper presents a formula for computing the diameter of $G_1\\otimes G_2$ by means of the diameters and primitive exponents of factor graphs.

  8. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  9. Mixed effect models for predicting breast height diameter from stump diameter of Oriental beech in Göldağ

    Directory of Open Access Journals (Sweden)

    Ilker Ercanli

    2015-06-01

    Full Text Available Diameter at breast height (DBH is the simplest, most common and most important tree dimension in forest inventory and is closely correlated with wood volume, height and biomass. In this study, a number of linear and nonlinear models predicting diameter at breast height from stump diameter were developed and evaluated for Oriental beech (Fagus orientalisLipsky stands located in the forest region of Ayancık, in the northeast of Turkey. A set of 1,501 pairs of diameter at breast height-stump measurements, originating from 70 sample plots of even-aged Oriental beech stands, were used in this study. About 80 % of the otal data (1,160 trees in 55 sample plots was used to fit a number of linear and nonlinear model parameters; the remaining 341 trees in 15 sample plots were randomly reserved for model validation and calibration response. The power model data set was found to produce the most satisfactory fits with the Adjusted Coefficient of Determination, R2adj (0.990, Root Mean Square Error, RMSE (1.25, Akaike’s Information Criterion, AIC (3820.5, Schwarz’s Bayesian Information Criterion, BIC (3837.2, and Absolute Bias (1.25. The nonlinear mixed-effect modeling approach for power model with R2adj(0.993, AIC (3598, BIC (3610.1, Absolute Bias (0.73 and RMSE (1.04 provided much better fitting and precise predictions for DBH from stump diameter than the conventional nonlinear fixed effect model structures for this model. The calibration response including tree DBH and stump diameter measurements of the four largest trees in a calibrated sample plot in calibration produced the highest Bias, -5.31 %, and RMSE, -6.30 %, the greatest reduction percentage.

  10. Uncertainty budget for optical coordinate measurements of circle diameter

    DEFF Research Database (Denmark)

    Morace, Renate Erica; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2004-01-01

    An uncertainty analysis for circle diameter measurements using a coordinate measuring machine (CMM) equipped with an optical probe is presented in this paper. A mathematical model for data evaluation and uncertainty assessment was formulated in accordance with Guide to the Expression of Uncertain...

  11. Experimental study on strain sensing by small-diameter FBG

    Science.gov (United States)

    Liu, Rong-mei; Li, Qiufeng; Zhu, Lujia; Liang, Dakai

    2016-11-01

    Fiber Bragg grating (FBG) sensors were attractive in various fields for structural health monitoring. Because of their accurate performance and real time response, embedded FBG sensors are promising for strain monitoring in composite materials. As an optical fiber sensor was embedded inside a composite, interface would form around the embedded optical fiber and the host polymer composite. In order to study the influence of the embedded optical fiber to the mechanical character, finite elemental analysis was applied to study the stress distribution inside the composite. Keeping the resin rich area the same size, laminates with optical fibers in different diameters, which were 250 and 125 micrometers, were analyzed. The simulation results represent that stress singularity would occur around the embedded optical fiber. The singularity value for the laminate with optical fiber at 250 micrometer was higher than that with optical fiber at 125 micrometer. Micro- cracks would arise at the stress singularity point. Therefore, the optical fiber in smaller diameter was preferred since the mechanical strength could be higher. Four points bending test was carried out on a steel beam with a small-diameter FBG on the bottom surface. Besides, a strain gauge was stuck on bottom to validate the monitoring results by FBG sensor. The tested results indicated that the strain monitoring results by the small-diameter FBG sensor almost identical with the theoretical ones and what recorded by strain gauge. The maximum testing error for the designed FBG is less than 2% compared with the theoretical one.

  12. Predicted and observed finger diameters in field soils

    NARCIS (Netherlands)

    Ritsema, C.J.; Steenhuis, T.S.; Parlange, J.Y.; Dekker, L.W.

    1996-01-01

    Wetting front instability resulting in fingered flow has been found in both wettable and non-wettable soils. Laboratory research has resulted in a number of expressions for finger diameter. The applicability of one of these equations was tested for three soils where detailed soil moisture contents w

  13. Pupil diameter covaries with BOLD activity in human locus coeruleus.

    Science.gov (United States)

    Murphy, Peter R; O'Connell, Redmond G; O'Sullivan, Michael; Robertson, Ian H; Balsters, Joshua H

    2014-08-01

    The locus coeruleus-noradrenergic (LC-NA) neuromodulatory system has been implicated in a broad array of cognitive processes, yet scope for investigating this system's function in humans is currently limited by an absence of reliable non-invasive measures of LC activity. Although pupil diameter has been employed as a proxy measure of LC activity in numerous studies, empirical evidence for a relationship between the two is lacking. In the present study, we sought to rigorously probe the relationship between pupil diameter and BOLD activity localized to the human LC. Simultaneous pupillometry and fMRI revealed a relationship between continuous pupil diameter and BOLD activity in a dorsal pontine cluster overlapping with the LC, as localized via neuromelanin-sensitive structural imaging and an LC atlas. This relationship was present both at rest and during performance of a two-stimulus oddball task, with and without spatial smoothing of the fMRI data, and survived retrospective image correction for physiological noise. Furthermore, the spatial extent of this pupil/LC relationship guided a volume-of-interest analysis in which we provide the first demonstration in humans of a fundamental characteristic of animal LC activity: phasic modulation by oddball stimulus relevance. Taken together, these findings highlight the potential for utilizing pupil diameter to achieve a more comprehensive understanding of the role of the LC-NA system in human cognition.

  14. Rowlinson’s concept of an effective hard sphere diameter

    Science.gov (United States)

    Henderson, Douglas

    2010-01-01

    Attention is drawn to John Rowlinson’s idea that the repulsive portion of the intermolecular interaction may be replaced by a temperature-dependent hard sphere diameter. It is this approximation that made the development of perturbation theory possible for realistic fluids whose intermolecular interactions have a steep, but finite, repulsion at short separations. PMID:20953320

  15. Rowlinson's concept of an effective hard sphere diameter.

    Science.gov (United States)

    Henderson, Douglas

    2010-01-01

    Attention is drawn to John Rowlinson's idea that the repulsive portion of the intermolecular interaction may be replaced by a temperature-dependent hard sphere diameter. It is this approximation that made the development of perturbation theory possible for realistic fluids whose intermolecular interactions have a steep, but finite, repulsion at short separations.

  16. Definition of Beam Diameter for Electron Beam Welding

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dvornak, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    It is useful to characterize the dimensions of the electron beam during process development for electron beam welding applications. Analysis of the behavior of electron beam welds is simplest when a single number can be assigned to the beam properties that describes the size of the beam spot; this value we generically call the “beam diameter”. This approach has worked well for most applications and electron beam welding machines with the weld dimensions (width and depth) correlating well with the beam diameter. However, in recent weld development for a refractory alloy, Ta-10W, welded with a low voltage electron beam machine (LVEB), it was found that the weld dimensions (weld penetration and weld width) did not correlate well with the beam diameter and especially with the experimentally determined sharp focus point. These data suggest that the presently used definition of beam diameter may not be optimal for all applications. The possible reasons for this discrepancy and a suggested possible alternative diameter definition is the subject of this paper.

  17. Diameter-dependent conductance of InAs nanowires

    NARCIS (Netherlands)

    Scheffler, M.; Nadj-Perge, S.; Kouwenhoven, L.P.; Borgström, M.T.; Bakkers, E.P.A.M.

    2009-01-01

    Electrical conductance through InAs nanowires is relevant for electronic applications as well as for fundamental quantum experiments. Here, we employ nominally undoped, slightly tapered InAs nanowires to study the diameter dependence of their conductance. By contacting multiple sections of each wire

  18. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    Science.gov (United States)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  19. A small-diameter NMR logging tool for groundwater investigations.

    Science.gov (United States)

    Walsh, David; Turner, Peter; Grunewald, Elliot; Zhang, Hong; Butler, James J; Reboulet, Ed; Knobbe, Steve; Christy, Tom; Lane, John W; Johnson, Carole D; Munday, Tim; Fitzpatrick, Andrew

    2013-01-01

    A small-diameter nuclear magnetic resonance (NMR) logging tool has been developed and field tested at various sites in the United States and Australia. A novel design approach has produced relatively inexpensive, small-diameter probes that can be run in open or PVC-cased boreholes as small as 2 inches in diameter. The complete system, including surface electronics and various downhole probes, has been successfully tested in small-diameter monitoring wells in a range of hydrogeological settings. A variant of the probe that can be deployed by a direct-push machine has also been developed and tested in the field. The new NMR logging tool provides reliable, direct, and high-resolution information that is of importance for groundwater studies. Specifically, the technology provides direct measurement of total water content (total porosity in the saturated zone or moisture content in the unsaturated zone), and estimates of relative pore-size distribution (bound vs. mobile water content) and hydraulic conductivity. The NMR measurements show good agreement with ancillary data from lithologic logs, geophysical logs, and hydrogeologic measurements, and provide valuable information for groundwater investigations.

  20. Estimating Tree Height-Diameter Models with the Bayesian Method

    Directory of Open Access Journals (Sweden)

    Xiongqing Zhang

    2014-01-01

    Full Text Available Six candidate height-diameter models were used to analyze the height-diameter relationships. The common methods for estimating the height-diameter models have taken the classical (frequentist approach based on the frequency interpretation of probability, for example, the nonlinear least squares method (NLS and the maximum likelihood method (ML. The Bayesian method has an exclusive advantage compared with classical method that the parameters to be estimated are regarded as random variables. In this study, the classical and Bayesian methods were used to estimate six height-diameter models, respectively. Both the classical method and Bayesian method showed that the Weibull model was the “best” model using data1. In addition, based on the Weibull model, data2 was used for comparing Bayesian method with informative priors with uninformative priors and classical method. The results showed that the improvement in prediction accuracy with Bayesian method led to narrower confidence bands of predicted value in comparison to that for the classical method, and the credible bands of parameters with informative priors were also narrower than uninformative priors and classical method. The estimated posterior distributions for parameters can be set as new priors in estimating the parameters using data2.

  1. Real-time precision measuring device of tree diameter growth

    Science.gov (United States)

    Guo, Mingming; Chen, Aijun; Li, Dongsheng; Liu, Nan; Yao, Jingyuan

    2016-01-01

    DBH(diameter at breast height) is an important factor to reflect of the quality of plant growth, also an important parameter indispensable in forest resources inventory and forest carbon sink, the accurate measurement of DBH or not is directly related to the research of forest resources inventory and forest carbon sink. In this paper, the principle and the mathematical model of DBH measurement device were introduced, the fixture measuring device and the hardware circuit for this tree diameter were designed, the measurement software programs were compiled, and the precision measuring device of tree diameter growth was developed. Some experiments with Australia fir were conducted. Based on experiment data, the correlations among the DBH variation of Australian fir, the environment temperature, air humility and PAR(photosynthetically active radiation) were obtained. The effects of environmental parameters (environment temperature, air humility and PAR) on tree diameter were analyzed. Experimental results show that there is a positive correlation between DBH variation of Australian fir and environment temperature, a negative correlation between DBH variation of Australian fir and air humility , so is PAR.

  2. Observations on placentome diameters in gestating West African ...

    African Journals Online (AJOL)

    ADEYEYE

    2015-09-09

    Sep 9, 2015 ... Department of Veterinary Surgery and Reproduction, University of Ibadan, Ibadan, Nigeria ... This study investigated the effect of experimental Trypanosoma brucei infection on the placentome diameter (PD) ... symptoms/clinical signs in female mammalian ..... Global Library Women's Medicine, London,.

  3. Small-diameter trees used for chemithermomechanical pulps.

    Science.gov (United States)

    Gary C. Myers; R. James. Barbour; Said M. Abubakr

    1999-01-01

    During the course of restoring and maintaining forest ecosystem health and function in the western interior of the United States, many small-diameter stems are removed from densely stocked stands. In general, these materials are considered nonusable or underutilized. Information on the properties of these resources is needed to help managers understand when timber...

  4. Processing of fine-diameter continuous mullite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Al-Assafi, S.; Cruse, T.; Simmons, J.H. [Univ. of Florida, Gainesville, FL (United States)] [and others

    1994-12-31

    Fine-diameter, continuous mullite fibers were fabricated by sol-gel processing using two different chelating agents on weight loss behavior, mullite formation, and sintered fiber microstructure were examined. The molar ratio, R, of chelating agent to alumina precursor in the sol was varied in order to optimize continuous spinning conditions. The importance of aging conditions on the sintered fiber density was demonstrated.

  5. Bipartite Diametrical Graphs of Diameter 4 and Extreme Orders

    Directory of Open Access Journals (Sweden)

    Salah Al-Addasi

    2008-01-01

    in which this upper bound is attained, this graph can be viewed as a generalization of the Rhombic Dodecahedron. Then we show that for any ≥2, the graph (2,2 is the unique (up to isomorphism bipartite diametrical graph of diameter 4 and partite sets of cardinalities 2 and 2, and hence in particular, for =3, the graph (6,8 which is just the Rhombic Dodecahedron is the unique (up to isomorphism bipartite diametrical graph of such a diameter and cardinalities of partite sets. Thus we complete a characterization of -graphs of diameter 4 and cardinality of the smaller partite set not exceeding 6. We prove that the neighborhoods of vertices of the larger partite set of (2,2 form a matroid whose basis graph is the hypercube . We prove that any -graph of diameter 4 is bipartite self complementary, thus in particular (2,2. Finally, we study some additional properties of (2,2 concerning the order of its automorphism group, girth, domination number, and when being Eulerian.

  6. Multi-diameter pigging: factors affecting the design and selection of pigging tools for multi-diameter pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Karl [Pipeline Engineering and Supply Co. Ltd., Richmond, NY (United States)

    2009-07-01

    This paper will consider the process involved in pigging tool selection for pipelines with two or more significant internal diameters which require pigging tools capable of negotiating the different internal diameters whilst also carrying out the necessary pipeline cleaning operation. The paper will include an analysis of pipeline features that affect pigging tool selection and then go on to look at other variables that determine the pigging tool design; this will include a step by step guide outlining how the tool is designed, the development of prototype pigs and the importance of testing and validation prior to final deployment in operational pigging programmes. (author)

  7. Vertebral Artery Diameter and Flow: Nature or Nurture.

    Science.gov (United States)

    Tarnoki, Adam Domonkos; Fejer, Bence; Tarnoki, David Laszlo; Littvay, Levente; Lucatelli, Pierleone; Cirelli, Carlo; Fanelli, Fabrizio; Sacconi, Beatrice; Fagnani, Corrado; Medda, Emanuela; Farina, Filippo; Meneghetti, Giorgio; Horvath, Tamas; Pucci, Giacomo; Schillaci, Giuseppe; Stazi, Maria Antonietta; Baracchini, Claudio

    2017-09-01

    In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited. A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed. Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%). The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound. Copyright © 2017 by the American Society of Neuroimaging.

  8. Stand diameter distribution modelling and prediction based on Richards function.

    Directory of Open Access Journals (Sweden)

    Ai-guo Duan

    Full Text Available The objective of this study was to introduce application of the Richards equation on modelling and prediction of stand diameter distribution. The long-term repeated measurement data sets, consisted of 309 diameter frequency distributions from Chinese fir (Cunninghamia lanceolata plantations in the southern China, were used. Also, 150 stands were used as fitting data, the other 159 stands were used for testing. Nonlinear regression method (NRM or maximum likelihood estimates method (MLEM were applied to estimate the parameters of models, and the parameter prediction method (PPM and parameter recovery method (PRM were used to predict the diameter distributions of unknown stands. Four main conclusions were obtained: (1 R distribution presented a more accurate simulation than three-parametric Weibull function; (2 the parameters p, q and r of R distribution proved to be its scale, location and shape parameters, and have a deep relationship with stand characteristics, which means the parameters of R distribution have good theoretical interpretation; (3 the ordinate of inflection point of R distribution has significant relativity with its skewness and kurtosis, and the fitted main distribution range for the cumulative diameter distribution of Chinese fir plantations was 0.4∼0.6; (4 the goodness-of-fit test showed diameter distributions of unknown stands can be well estimated by applying R distribution based on PRM or the combination of PPM and PRM under the condition that only quadratic mean DBH or plus stand age are known, and the non-rejection rates were near 80%, which are higher than the 72.33% non-rejection rate of three-parametric Weibull function based on the combination of PPM and PRM.

  9. Stand diameter distribution modelling and prediction based on Richards function.

    Science.gov (United States)

    Duan, Ai-guo; Zhang, Jian-guo; Zhang, Xiong-qing; He, Cai-yun

    2013-01-01

    The objective of this study was to introduce application of the Richards equation on modelling and prediction of stand diameter distribution. The long-term repeated measurement data sets, consisted of 309 diameter frequency distributions from Chinese fir (Cunninghamia lanceolata) plantations in the southern China, were used. Also, 150 stands were used as fitting data, the other 159 stands were used for testing. Nonlinear regression method (NRM) or maximum likelihood estimates method (MLEM) were applied to estimate the parameters of models, and the parameter prediction method (PPM) and parameter recovery method (PRM) were used to predict the diameter distributions of unknown stands. Four main conclusions were obtained: (1) R distribution presented a more accurate simulation than three-parametric Weibull function; (2) the parameters p, q and r of R distribution proved to be its scale, location and shape parameters, and have a deep relationship with stand characteristics, which means the parameters of R distribution have good theoretical interpretation; (3) the ordinate of inflection point of R distribution has significant relativity with its skewness and kurtosis, and the fitted main distribution range for the cumulative diameter distribution of Chinese fir plantations was 0.4∼0.6; (4) the goodness-of-fit test showed diameter distributions of unknown stands can be well estimated by applying R distribution based on PRM or the combination of PPM and PRM under the condition that only quadratic mean DBH or plus stand age are known, and the non-rejection rates were near 80%, which are higher than the 72.33% non-rejection rate of three-parametric Weibull function based on the combination of PPM and PRM.

  10. Arteriolar Diameters in Glaucomatous Eyes with Single-Hemifield Damage.

    Science.gov (United States)

    Russo, Andrea; Costagliola, Ciro; Rizzoni, Damiano; Ghilardi, Nausica; Turano, Raffaele; Semeraro, Francesco

    2016-05-01

    To examine the association between retinal arteriolar caliber and lumen, retinal sensitivity (RS), and retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes with single-hemifield loss. We conducted a prospective, nonrandomized, case-control study of 20 eyes of 20 patients with glaucoma with visual field damage confined to a single hemifield. The control group was composed of 20 eyes of 20 normal subjects. For all the eyes, we performed optical coherence tomography to assess the RNFL and standard automated perimetry to evaluate RS. External and internal arteriolar diameters were assessed in vivo using scanning laser Doppler flowmetry. The RNFL was significantly thinner in glaucomatous eyes than in normal eyes (p < 0.001). In glaucomatous eyes, a positive correlation between sectorial RNFL thickness and the corresponding external and internal arteriolar diameters was found (r = 0.43, p = 0.05; r = 0.63, p = 0.003, respectively). The internal arteriolar diameter significantly correlated with RS in the corresponding abnormal hemifield (r = 0.44, p = 0.04). Compared with the normal hemifield, the internal arteriolar diameter, RNFL thickness, and RS were significantly reduced, whereas the external arteriolar diameter was unchanged in the abnormal hemifield. In glaucomatous eyes with single-hemifield damage, attenuation of retinal vessels was associated with a thinner RNFL and reduced RS. Moreover, a narrower lumen with increased wall-to-lumen ratio was found in the abnormal hemifield, supporting the hypothesis that vessel narrowing is likely secondary to a lower demand for blood flow in the glaucomatous areas of the retina.

  11. Measurement error in CT assessment of appendix diameter

    Energy Technology Data Exchange (ETDEWEB)

    Trout, Andrew T.; Towbin, Alexander J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States); Zhang, Bin [Cincinnati Children' s Hospital Medical Center, Department of Biostatistics and Epidemiology, Cincinnati, OH (United States)

    2016-12-15

    Appendiceal diameter continues to be cited as an important criterion for diagnosis of appendicitis by computed tomography (CT). To assess sources of error and variability in appendiceal diameter measurements by CT. In this institutional review board-approved review of imaging and medical records, we reviewed CTs performed in children <18 years of age between Jan. 1 and Dec. 31, 2010. Appendiceal diameter was measured in the axial and coronal planes by two reviewers (R1, R2). One year later, 10% of cases were remeasured. For patients who had multiple CTs, serial measurements were made to assess within patient variability. Measurement differences between planes, within and between reviewers, within patients and between CT and pathological measurements were assessed using correlation coefficients and paired t-tests. Six hundred thirty-one CTs performed in 519 patients (mean age: 10.9 ± 4.9 years, 50.8% female) were reviewed. Axial and coronal measurements were strongly correlated (r = 0.92-0.94, P < 0.0001) with coronal plane measurements significantly larger (P < 0.0001). Measurements were strongly correlated between reviewers (r = 0.89-0.9, P < 0.0001) but differed significantly in both planes (axial: +0.2 mm, P=0.003; coronal: +0.1 mm, P=0.007). Repeat measurements were significantly different for one reviewer only in the axial plane (0.3 mm difference, P<0.05). Within patients imaged multiple times, measured appendix diameters differed significantly in the axial plane for both reviewers (R1: 0.5 mm, P = 0.031; R2: 0.7 mm, P = 0.022). Multiple potential sources of measurement error raise concern about the use of rigid diameter cutoffs for the diagnosis of acute appendicitis by CT. (orig.)

  12. Middle cerebral artery diameter changes during rhythmic handgrip exercise in humans.

    Science.gov (United States)

    Verbree, J; Bronzwaer, Agt; van Buchem, M A; Daemen, Mjap; van Lieshout, J J; van Osch, Mjp

    2017-08-01

    Transcranial Doppler (TCD) sonography is a frequently employed technique for quantifying cerebral blood flow by assuming a constant arterial diameter. Given that exercise increases arterial pressure by sympathetic activation, we hypothesized that exercise might induce a change in the diameter of large cerebral arteries. Middle cerebral artery (MCA) cross-sectional area was assessed in response to handgrip exercise by direct magnetic resonance imaging (MRI) observations. Twenty healthy subjects (11 female) performed three 5 min bouts of rhythmic handgrip exercise at 60% maximum voluntary contraction, alternated with 5 min of rest. High-resolution 7 T MRI scans were acquired perpendicular to the MCA. Two blinded observers manually determined the MCA cross-sectional area. Sufficient image quality was obtained in 101 MCA-scans of 19 subjects (age-range 20-59 years). Mixed effects modelling showed that the MCA cross-sectional area decreased by 2.1 ± 0.8% (p = 0.01) during handgrip, while the heart rate increased by 11 ± 2% (p exercise. This further strengthens the current concept of sympathetic control of large cerebral arteries, showing in vivo vasoconstriction during exercise-induced sympathetic activation. Moreover, care must be taken when interpreting TCD exercise studies as diameter constancy cannot be assumed.

  13. SOME OBSERVATIONS OF TWO INTERFERING VIV CIRCULAR CYLINDERS OF UNEQUAL DIAMETERS IN TANDEM

    Institute of Scientific and Technical Information of China (English)

    HUANG Shan; SWORN Andy

    2011-01-01

    Analysis of model test results was carried out to investigate the hydrodynamic interaction between a pair of elastically-supported rigid cylinders of dissimilar diameters in a water flume.The two cylinders are placed in tandem with one situated in the wake of the other.The diameter of the upstream cylinder is twice as large as that of the downstream cylinder.The spacing between the two cylinders ranges from 1 to 10 times the larger cylinder diameter.The Reynolds numbers are within the sub-critical range.The cylinders are free to oscillate in both the in-line and the cross-flow directions.The reduced velocity ranges from 1 to 10 and the low damping ratio of the model test set-up at 0.006 gives a combined m.ass-damping parameter of 0.02.It is found that the lift on and the cross-flow motion of the downstream cylinder have the frequency components derived from the upstream cylinder's vortex shedding as well as from its own vortex shedding,and the relative importance of the two sources of excitation is influenced by the spacing between the two cylinders.The downstream cylinder's VIV response appears to be largely dependent upon the actual reduced velocity of the cylinder.

  14. Engineering of an E. coli outer membrane protein FhuA with increased channel diameter

    Directory of Open Access Journals (Sweden)

    Dworeck Tamara

    2011-08-01

    Full Text Available Abstract Background Channel proteins like FhuA can be an alternative to artificial chemically synthesized nanopores. To reach such goals, channel proteins must be flexible enough to be modified in their geometry, i.e. length and diameter. As continuation of a previous study in which we addressed the lengthening of the channel, here we report the increasing of the channel diameter by genetic engineering. Results The FhuA Δ1-159 diameter increase has been obtained by doubling the amino acid sequence of the first two N-terminal β-strands, resulting in variant FhuA Δ1-159 Exp. The total number of β-strands increased from 22 to 24 and the channel surface area is expected to increase by ~16%. The secondary structure analysis by circular dichroism (CD spectroscopy shows a high β-sheet content, suggesting the correct folding of FhuA Δ1-159 Exp. To further prove the FhuA Δ1-159 Exp channel functionality, kinetic measurement using the HRP-TMB assay (HRP = Horse Radish Peroxidase, TMB = 3,3',5,5'-tetramethylbenzidine were conducted. The results indicated a 17% faster diffusion kinetic for FhuA Δ1-159 Exp as compared to FhuA Δ1-159, well correlated to the expected channel surface area increase of ~16%. Conclusion In this study using a simple "semi rational" approach the FhuA Δ1-159 diameter was enlarged. By combining the actual results with the previous ones on the FhuA Δ1-159 lengthening a new set of synthetic nanochannels with desired lengths and diameters can be produced, broadening the FhuA Δ1-159 applications. As large scale protein production is possible our approach can give a contribution to nanochannel industrial applications.

  15. Aneurysm diameter and proximal aortic neck diameter influence clinical outcome of endovascular abdominal aortic repair : A 4-year EUROSTAR experience

    NARCIS (Netherlands)

    Waasdorp, EJ; de Vries, JPPM; Hobo, R; Leurs, LJ; Buth, J; Moll, FL

    2005-01-01

    Our objective was to evaluate the effect of preoperative aneurysm and aortic neck diameter on clinical outcome after infrarenal abdominal endovascular aneurysm repair (EVAR). Data of patients in the European Collaborators Registry on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROS

  16. Height-diameter allometry of tropical forest trees

    Directory of Open Access Journals (Sweden)

    T. R. Feldpausch

    2011-05-01

    Full Text Available Tropical tree height-diameter (H:D relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were:

    1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap.

    2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A.

    3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass.

    Annual precipitation coefficient of variation (PV, dry season length (SD, and mean annual air temperature (TA emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in

  17. Height-diameter allometry of tropical forest trees

    Directory of Open Access Journals (Sweden)

    T. R. Feldpausch

    2010-10-01

    Full Text Available Tropical tree height-diameter (H:D relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were:

      1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap.

      2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A.

      3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass.

    Annual precipitation coefficient of variation (PV, dry season length (SD, and mean annual air temperature (TA emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere.

    The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within a median –2.7 to 0.9% of the true value. Some of the plot

  18. Tunable diameter electrostatically formed nanowire for high sensitivity gas sensing

    Institute of Scientific and Technical Information of China (English)

    Alex Henning; Nandhini Swaminathan; Andrey Godkin; Gil Shalev; Iddo Amit; Yossi Rosenwaks

    2015-01-01

    We report on an electrostatically formed nanowire (EFN)-based sensor with tunable diameters in the range of 16 nm to 46 nm and demonstrate an EFN- based field-effect transistor as a highly sensitive and robust room temperature gas sensor. The device was carefully designed and fabricated using standard integrated processing to achieve the 16 nm EFN that can be used for sensing without any need for surface modification. The effective diameter for the EFN was determined using Kelvin probe force microscopy accompanied by three- dimensional electrostatic simulations. We show that the EFN transistor is capable of detecting 100 parts per million of ethanol gas with bare SiO2.

  19. Angular diameter distances reconsidered in the Newman and Penrose formalism

    CERN Document Server

    Kling, Thomas P

    2016-01-01

    Using the Newman and Penrose spin coefficient (NP) formalism, we provide a derivation of the Dyer-Roeder equation for the angular diameter distance in cosmological space-times. We show that the geodesic deviation equation written in NP formalism is precisely the Dyer-Roeder equation for a general Friedman-Robertson-Walker (FRW) space-time, and then we examine the angular diameter distance to redshift relation in the case that a flat FRW metric is perturbed by a gravitational potential. We examine the perturbation in the case that the gravitational potential exhibits the properties of a thin gravitational lens, demonstrating how the weak lensing shear and convergence act as source terms for the perturbed Dyer-Roeder equation.

  20. Visual function and retinal vessel diameters during hyperthermia in man

    DEFF Research Database (Denmark)

    Jensen, Bettina Hagström; Bram, Thue; Kappelgaard, Per

    2017-01-01

    laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling. RESULTS: The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p ... in cling film, tinfoil and warming blankets. Subsequent cooling was achieved by undressing. Flicker sensitivity (critical flicker fusion frequency) was chosen to assess temporal resolution, while the Freiburg Vision Test was used to determine spatial contrast sensitivity at 1.5 cycles per degree. Scanning...... diameters (CI95 0.96-4.94, p cooling. CONCLUSION: Increased core body temperature was accompanied by improved temporal visual resolution and retinal trunk...

  1. Consequences of the Continuity of the Monic Integer Transfinite Diameter

    CERN Document Server

    Hilmar, Jan

    2007-01-01

    We consider the problem of determining the monic integer transfinite diameter t_M(I)&=&\\lim_{n\\to\\infty}\\inf_{p_n\\in{\\mathcal M_n}}\\supnorm{p_n}{I}^{1/n} for real intervals of length less than 4. We show the $t_M([0,x])$, as a function in $x>0$, is continuous, therefore disproving two conjectures due to Hare and Smyth. Consequently, for $n>2\\in\

  2. A study of the heated length to diameter effects

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Ho; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    An analytical and experimental investigation has been performed on the heated length-to-diameter effect on critical heat flux exit conditions. A L/D correction factor is developed by applying artificial neural network and conventional regression techniques to the KAIST CHF data base. In addition, experiment is being performed to validate the developed L/D correction factor with independent data. Assessment shows that the developed correction factor is promising for practical applications. 6 refs., 8 figs. (Author)

  3. Retinal vessel diameter changes induced by transient high perfusion pressure

    Institute of Scientific and Technical Information of China (English)

    Yin-Ying; Zhao; Ping-Jun; Chang; Fang; Yu; Yun-E; Zhao

    2014-01-01

    ·AIM: To investigate the effects of transient high perfusion pressure on the retinal vessel diameter and retinal ganglion cells.·METHODS: The animals were divided into four groups according to different infusion pressure and infusion time(60 mm Hg-3min, 60 mm Hg-5min, 100 mm Hg-3min, 100 mm Hg-5min). Each group consisted of six rabbits. The left eye was used as the experimental eye and the right as a control. Retinal vascular diameters were evaluated before, during infusion, immediately after infusion, 5min, 10 min and 30 min after infusion based on the fundus photographs. Blood pressure was monitored during infusion. The eyes were removed after 24 h.Damage to retinal ganglion cell(RGC) was analyzed by histology.·RESULTS: Retina became whiten and papilla optic was pale during perfusion. Measurements showed significant decrease in retinal artery and vein diameter during perfusion in all of the four groups at the proximal of the edge of the optic disc. The changes were significant in the 100 mm Hg-3min group and 100 mm Hg-5min group compared with 60 mm Hg-3min group(P 1=0.025, P 2=0.000).The diameters in all the groups recovered completely after 30 min of reperfusion. The number of RGC)showed no significant changes at the IOP in 100 mm Hg with5 min compared with contralateral untreated eye(P >0.05).·CONCLUSION: Transient fluctuations during infusion lead to temporal changes of retinal vessels, which could affect the retinal blood circulation. The RGCs were not affected by this transient fluctuation. Further studies are necessary to evaluate the effect of pressure during realtime phacoemusification on retinal blood circulation.

  4. Uncertainty budget for optical coordinate measurements of circle diameter

    DEFF Research Database (Denmark)

    Morace, Renate Erica; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2004-01-01

    An uncertainty analysis for circle diameter measurements using a coordinate measuring machine (CMM) equipped with an optical probe is presented in this paper. A mathematical model for data evaluation and uncertainty assessment was formulated in accordance with Guide to the Expression of Uncertainty...... in Measurement (GUM). Various input quantities such as CCD camera resolution, influence of illuminating system, CMM errors etc. were considered in the model function and experimentally investigated....

  5. Pupil Center as a Function of Pupil Diameter

    DEFF Research Database (Denmark)

    Ahmed, Zaheer; Mardanbegi, Diako; Hansen, Dan Witzner

    2016-01-01

    We investigate the gaze estimation error induced by pupil size changes using simulated data. We investigate the influence of pupil diameter changes on estimated gaze point error obtained by two gaze estimation models. Simulation data show that at wider viewing angles and at small eye......-camera distances, error increases with increasing pupil sizes. The maximum error recorded for refracted pupil images is 2.4° of visual angle and 1.5° for non-refracted pupil projections....

  6. THE CUTWIDTH OF TREES WITH DIAMETER AT MOST 4

    Institute of Scientific and Technical Information of China (English)

    LinYixun

    2003-01-01

    The cutwidth problem for a graph G is to embed G into a path Pn such that the maximum number of overlap edges (i. e. , the congestion) is minimized. It is known that the problem for general graphs is NP-hard while it is polynomially solvable for trees. This paper presents an exact formula for the cutwidth of trees with diameter at most 4. A relation with the bandwidth is discussed as well.

  7. Visual function and retinal vessel diameters during hyperthermia in man.

    Science.gov (United States)

    Jensen, Bettina Hagström; Bram, Thue; Kappelgaard, Per; Arvidsson, Henrik; Loskutova, Ekaterina; Munch, Inger Christine; Larsen, Michael

    2016-12-21

    To assess the effect of elevated core body temperature on temporal and spatial contrast sensitivity and retinal vessel diameters. The study included 13 healthy volunteers aged 20-37 years. Core body temperature elevation (target +1.1°C) was induced by wrapping the participants in cling film, tinfoil and warming blankets. Subsequent cooling was achieved by undressing. Flicker sensitivity (critical flicker fusion frequency) was chosen to assess temporal resolution, while the Freiburg Vision Test was used to determine spatial contrast sensitivity at 1.5 cycles per degree. Scanning laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling. The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p < 0.01), a 10.6-mmHg mean reduction in diastolic blood pressure (p < 0.01), a mean increase in pulse rate of 36.3 bpm (p < 0.0001), a 2.66% improvement in flicker sensitivity (CI95 1.37-3.94, p < 0.001), a 2.80% increase in retinal artery diameters (CI95 1.09-4.51, p < 0.01) and a 2.95% increase in retinal vein diameters (CI95 0.96-4.94, p < 0.01). There was no detectable effect of temperature on spatial contrast sensitivity. All ocular test parameters returned to baseline levels after cooling. Increased core body temperature was accompanied by improved temporal visual resolution and retinal trunk vessel dilation. The results suggest that hyperthermia is associated with enhanced retinal function and increased retinal metabolism. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  8. Alveolar echinococcosis: correlation of imaging type with PNM stage and diameter of lesions

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; XING Yan; REN Bo; XIE Wei-dong; WEN Hao; LIU Wen-ya

    2011-01-01

    Background Although the computer tomography (Cr) or magnetic resonance imaging (MRI) findings of alveolar echinococcosis (AE) have been well documented, the consecutive imaging changes of this disease in each PNM stage (parasite lesion, neighboring organ invasion, metastases) were not described accurately. The aim of this study was to analyze the correlation between imaging type and PNM stage and diameter of AE lesions, and to explore the development features of this disease.Methods A total of 87 patients with AE were examined using CT and MRI before medical management. Imaging features including the maximum diameter, calcification pattern, and imaging type of lesion were retrospectively assessed.The correlation of imaging type with PNM stage, diameter and calcification pattern was analyzed.Results Lesions (n=111) in 87 patients were divided into three types based on imaging characteristics; solid type (33.3%, 37/111, a solid lesion without liquid necrosis or only small patches of necrosis), mixed type (41.4%, 46/111, solid component surrounding large and/or irregular liquid necrosis area), and pseudo-cystic type (25.2%, 28/111, large cyst without visible solid component). Lesion calcification in the alveolar echinococcosis was categorized into three patterns;mild calcification (45.1%, 50/111, i.e. inconspicuous calcification or punctuate scattered calcification), moderate calcification (46.8%, 52/111, coastline calcification located at the periphery of the lesion, with or without the central dot-calcification) and abundant calcification (8.1%, 9/111, large calcified deposits). Significant differences were found between pseudo-cystic type and other two types in PNM stage, maximum diameter and calcification (P <0.05), but there was no significant difference between solid type and mixed type in those mentioned aspects (P >0.05). No correlation was observed between calcification patterns and maximum diameter (P >0.05).Conclusions Solid and mixed type

  9. Reliability of Two Diameters Method in Determining Acute Infarct Size. Validation as New Imaging Biomarker.

    Directory of Open Access Journals (Sweden)

    Jochen B Fiebach

    Full Text Available In order to select patients most likely to benefit for thrombolysis and to predict patient outcome in acute ischemic stroke, the volumetric assessment of the infarcted tissue is used. However, infarct volume estimation on Diffusion weighted imaging (DWI has moderate interrater variability despite the excellent contrast between ischemic lesion and healthy tissue. In this study, we compared volumetric measurements of DWI hyperintensity to a simple maximum orthogonal diameter approach to identify thresholds indicating infarct size >70 ml and >100 ml.Patients presenting with ischemic stroke with an NIHSS of ≥ 8 were examined with stroke MRI within 24 h after symptom onset. For assessment of the orthogonal DWI lesion diameters (od-values the image with the largest lesion appearance was chosen. The maximal diameter of the lesion was determined and a second diameter was measured perpendicular. Both diameters were multiplied. Od-values were compared to volumetric measurement and od-value thresholds identifying a lesion size of > 70 ml and > 100 ml were determined. In a selected dataset with an even distribution of lesion sizes we compared the results of the od value thresholds with results of the ABC/2 and estimations of lesion volumes made by two resident physicians.For 108 included patients (53 female, mean age 71.36 years with a median infarct volume of 13.4 ml we found an excellent correlation between volumetric measures and od-values (r2 = 0.951. Infarct volume >100 ml corresponds to an od-value cut off of 42; > 70 ml corresponds to an od-value of 32. In the compiled dataset (n = 50 od-value thresholds identified infarcts > 100 ml / > 70 ml with a sensitivity of 90%/ 93% and with a specificity of 98%/ 89%. The od-value offered a higher accuracy in identifying large infarctions compared to both visual estimations and the ABC/2 method.The simple od-value enables identification of large DWI lesions in acute stroke. The cutoff of 42 is useful to

  10. PREPARATION AND ADSORBABILITY OF DEXTRAN MICROSPHERES WITH UNIFORM DIAMETER

    Institute of Scientific and Technical Information of China (English)

    Ri-sheng Yao; Wen-xia Gao; Jing Sun; Ya-hua You

    2005-01-01

    The method of preparing uniform dextran microspheres with a narrow diameter distribution was introduced and the adsorbability of these microspheres was evaluated. The microspheres were prepared in W/O microemulsion using 0.5% dextran solution as the aqueous phase and n-hexane as the oil phase. Characteristics of the prepared dextran microspheres were examined with laser light blocking technique, optical microscope and ultraviolet spectrometer. The results show that the prepared dextran microspheres have uniform morphology and narrow diameter distribution, nearly 92% of them having a diameter of 56.6 μm. In vitro evaluation of adsorbability, wet dextran microspheres have good adsorption of 98.32 mg/g of model drug methylene blue in 20.86 mg/L methylene blue solution at 25℃. The adsorption of dried dextran microspheres under the same condition is 132.15 mg/g, which is even higher. And the adsorbability of dextran microspheres has significant relationship with the concentration of methylene blue and temperature. The adsorbability is better at lower temperature and higher concentration of methylene blue.

  11. Effects of Pupil Diameter on Light Detection and Temporal Modulation

    Institute of Scientific and Technical Information of China (English)

    Rachel S Li; Andrew W Siu; Johnny C Liyu; Elice C Chan

    2003-01-01

    Purpose: This study compared the effects of pupil variation on light detection and temporal modulation across the central visual field.Methods:Light detection sensitivity (LDS) and low flickering frequency (6Hz) temporal modulation sensitivity (TMS) of 20 young subjects were measured from the central visual field of the right eyes using an automated perimeter (Medmont M600). The measurements were taken under 3 artificial pupils, I.e. 3 mm, 4.3 mm and 6 mm diameters.The sensitivities were grouped and averaged for different retinal eccentricities(3°, 6°, 10° and 15°).Results:TMS and LDS were reduced with increasing retinal eccentricities( P < 0.001)and decreasing pupil diameters( P < 0.001). TMS collected from all pupil diameters were significantly different from each other( P < 0.001). Similarly, LDS under 3 mm pupil was statistically different from those of 4.3 mm and 6 mm(P < 0.003). Comparison of the hills of vision showed that pupil variation resulted in significantly different slopes (P=0.001).The slopes were also found to be significantly different between TMS and LDS (P=0.012).Conclusions: The data showed that dilated pupil resulted in significantly higher sensitivities than those of smaller pupil for both visual functions. The difference in the slopes of hills of vision also suggested that the variation in retinal illumination affected the visual responses differently at various retinal eccentricitities for TMS and LDS.

  12. Effect of conical nanopore diameter on ion current rectification.

    Science.gov (United States)

    Kovarik, Michelle L; Zhou, Kaimeng; Jacobson, Stephen C

    2009-12-10

    Asymmetric nanoscale conduits, such as conical track-etch pores, rectify ion current due to surface charge effects. To date, most data concerning this phenomenon have been obtained for small nanopores with diameters comparable to the electrical double layer thickness. Here, we systematically evaluate rectification for nanopores in poly(ethylene terephthalate) membranes with tip diameters of 10, 35, 85, and 380 nm. Current-voltage behavior is determined for buffer concentrations from 1 mM to 1 M and pHs 3.4 and 6.7. In general, ion current rectification increases with decreasing tip diameter, with decreasing ionic strength, and at higher pH. Surface charge contributes to increased pore conductivities compared to bulk buffer conductivities, though double layer overlap is not necessary for rectification to occur. Interestingly, the 35 nm pore exhibits a maximum rectification ratio for the 0.01 M buffer at pH 6.7, and the 380 nm pores exhibit nearly diodelike current-voltage curves when initially etched and strong rectification after the ion current has stabilized.

  13. Time-delay Cosmography: Increased Leverage with Angular Diameter Distances

    CERN Document Server

    Jee, Inh; Suyu, Sherry H; Huterer, Dragan

    2015-01-01

    Strong lensing time-delay systems constrain cosmological parameters via the so-called time-delay distance and the angular diameter distance to the lens. In previous studies, only the former information was used. In this paper, we show that the cosmological constraints improve significantly when the latter information is also included. Specifically, the angular diameter distance plays a crucial role in breaking the degeneracy between the curvature of the Universe and the time-varying equation of state of dark energy. Using a mock sample of 55 bright quadruple lens systems based on expectations for ongoing/future imaging surveys, we find that adding the angular diameter distance information to the time-delay distance information and the cosmic microwave background data of Planck improves the constraint on the constant equation of state by 30%, on the time variation in the equation of state by a factor of two, and on the Hubble constant in the flat $\\Lambda$CDM model by a factor of two. Therefore, previous forec...

  14. Time-delay cosmography: increased leverage with angular diameter distances

    Science.gov (United States)

    Jee, I.; Komatsu, E.; Suyu, S. H.; Huterer, D.

    2016-04-01

    Strong lensing time-delay systems constrain cosmological parameters via the so-called time-delay distance and the angular diameter distance to the lens. In previous studies, only the former information was used in forecasting cosmographic constraints. In this paper, we show that the cosmological constraints improve significantly when the latter information is also included. Specifically, the angular diameter distance plays a crucial role in breaking the degeneracy between the curvature of the Universe and the time-varying equation of state of dark energy. Using a mock sample of 55 bright quadruple lens systems based on expectations for ongoing/future imaging surveys, we find that adding the angular diameter distance information to the time-delay distance information and the Planck's measurements of the cosmic microwave background anisotropies improves the constraint on the constant equation of state by 30%, on the time variation in the equation of state by a factor of two, and on the Hubble constant in the flat ΛCDM model by a factor of two. Therefore, previous forecasts for the statistical power of time-delay systems were overly pessimistic, i.e., time-delay systems are more powerful than previously appreciated.

  15. Real-time diameter measurement using diffuse light

    Science.gov (United States)

    Luo, Xiaohe; Hui, Mei; Zhu, Qiudong; Wang, Shanshan

    2016-09-01

    A method for on-line rapid determination of the diameter of metallic cylinder is introduced in this paper. Under the radiation of diffuse light, there is a bright area close to the margin of metallic cylinder, and the method of this paper is based on the intensity distribution of the bright area. In this paper, with the radiation by a diffuse plane light with special shape, we present the relation expression of the distance between the peak point and the real edge of the cylinder and the distance between the diffuse light and the pinhole aperture of the camera. With the expression, the diameter of the cylinder to be measured can be calculated. In the experiments, monochromatic LED uniting with ground glass forms the diffuse light source, then the light irradiates the tested cylinder. After the cylinder, we use a lens with a front pinhole stop to choose the light into CMOS, then a computer is used to analyze images and export the measurement results. The measuring system using this method is very easily implemented, so it can realize the on-line rapid measurement. Experimental results are presented for six metallic cylinders with the diameter in 5 18mm range and roughness in Ra- 0.02um, and the precision reaches 3um.

  16. Purification of 1.9-nm-diameter semiconducting single-wall carbon nanotubes by temperature-controlled gel-column chromatography and its application to thin-film transistor devices

    Science.gov (United States)

    Thendie, Boanerges; Omachi, Haruka; Hirotani, Jun; Ohno, Yutaka; Miyata, Yasumitsu; Shinohara, Hisanori

    2017-06-01

    Large-diameter semiconductor single-wall carbon nanotubes (s-SWCNTs) have superior mobility and conductivity to small-diameter s-SWCNTs. However, the purification of s-SWCNTs with diameters larger than 1.6 nm by gel filtration has been difficult owing to the low selectivity of the conventional purification method in these large-diameter regions. We report a combination of temperature-controlled gel filtration and the gradient elution technique that we developed to enrich a high-purity s-SWCNT with a diameter as large as 1.9 nm. The thin-film transistor (TFT) device using the 1.9-nm-diameter SWCNT shows an average channel mobility of 23.7 cm2 V-1 s-1, which is much higher than those of conventional SWCNT-TFTs with smaller-diameters of 1.5 and 1.4 nm.

  17. Anatomical and Functional Estimations of Brachial Artery Diameter and Elasticity Using Oscillometric Measurements with a Quantitative Approach

    OpenAIRE

    Yoshinaga, Keiichiro; Fujii, Satoshi; Tomiyama, Yuuki; Takeuchi, Keisuke; Tamaki, Nagara

    2016-01-01

    Noninvasive vascular function measurement plays an important role in detecting early stages of atherosclerosis and in evaluating therapeutic responses. In this regard, recently, new vascular function measurements have been developed. These new measurements have been used to evaluate vascular function in coronary arteries, large aortic arteries, or peripheral arteries. Increasing vascular diameter represents vascular remodeling related to atherosclerosis. Attenuated vascular elasticity may be ...

  18. Spatial characteristics of tree diameter distributions in a temperate old-growth forest.

    Science.gov (United States)

    Zhang, Chunyu; Wei, Yanbo; Zhao, Xiuhai; von Gadow, Klaus

    2013-01-01

    This contribution identifies spatial characteristics of tree diameter in a temperate forest in north-eastern China, based on a fully censused observational study area covering 500×600 m. Mark correlation analysis with three null hypothesis models was used to determine departure from expectations at different neighborhood distances. Tree positions are clumped at all investigated scales in all 37 studied species, while the diameters of most species are spatially negatively correlated, especially at short distances. Interestingly, all three cases showing short-distance attraction of dbh marks are associated with light-demanding shrub species. The short-distance attraction of dbh marks indicates spatially aggregated cohorts of stems of similar size. The percentage of species showing significant dbh suppression peaked at a 4 m distance under the heterogeneous Poisson model. At scales exceeding the peak distance, the percentage of species showing significant dbh suppression decreases sharply with increasing distances. The evidence from this large observational study shows that some of the variation of the spatial characteristics of tree diameters is related variations of topography and soil chemistry. However, an obvious interpretation of this result is still lacking. Thus, removing competitors surrounding the target trees is an effective way to avoid neighboring competition effects reducing the growth of valuable target trees in forest management practice.

  19. Experimental and Numerical Investigation of a 60cm Diameter Bladeless Fan

    Directory of Open Access Journals (Sweden)

    mohammad jafari

    2016-01-01

    Full Text Available Bladeless fan is a novel type of fan with an unusual geometry and unique characteristics. This type of fan has been recently developed for domestic applications in sizes typically up to 30cm diameter. In the present study, a Bladeless fan with a diameter of 60cm was designed and constructed, in order to investigate feasibility of its usage in various industries with large dimensions. Firstly, flow field passed through this fan was studied by 3D modeling. Aerodynamic and aeroacoustic performance of the fan were considered via solving the conservation of mass and momentum equations in their unsteady form. To validate the acoustic code, NACA 0012 airfoil was simulated in a two dimension domain and the emitted noise was calculated for Re=2×105. Good agreement between numerical and experimental results was observed by applying FW-H equations for predicting noise of the fan. To validate the simulated aerodynamic results, a Bladeless fan with a 60cm diameter was constructed and experimentally tested. In addition, the difference between the experimental and numerical results was acceptable for this fan. Moreover, the experimental results in the present study showed that this fan is capable to be designed and used for various industrial applications.

  20. Development of a 32 Inch Diameter Levitated Ducted Fan Conceptual Design

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher a.; Solano, Paul A.; Thompson, William K.; Vrnak, Daniel R.

    2006-01-01

    The NASA John H. Glenn Research Center has developed a revolutionary 32 in. diameter Levitated Ducted Fan (LDF) conceptual design. The objective of this work is to develop a viable non-contact propulsion system utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels, and mitigate many of the concerns and limitations encountered in conventional aircraft propulsors. The physical layout consists of a ducted fan drum rotor with blades attached at the outer diameter and supported by a stress tuner ring at the inner diameter. The rotor is contained within a stator. This concept exploits the unique physical dimensions and large available surface area to optimize a custom, integrated, electromagnetic system that provides both the levitation and propulsion functions. The rotor is driven by modulated electromagnetic fields between the rotor and the stator. When set in motion, the time varying magnetic fields interact with passive coils in the stator assembly to produce repulsive forces between the stator and the rotor providing magnetic suspension. LDF can provide significant improvements in aviation efficiency, reliability, and safety, and has potential application in ultra-efficient motors, computers, and space power systems.

  1. Three-dimensional flow around two circular cylinders of different diameters in a close proximity

    Science.gov (United States)

    Thapa, Jitendra; Zhao, Ming; Cheng, Liang; Zhou, Tongming

    2015-08-01

    Flow past two cylinders of different diameters in close proximity is simulated numerically for a constant diameter ratio of 0.45, a gap ratio of 0.0625, and a Reynolds number of 1000 (defined using the diameter of the main cylinder). The effect of the position angle α of the small cylinder relative to the large one on force coefficients and wake flow patterns are studied. Depending on the position angle α of the small cylinder, four wake flow modes are identified: the upstream interference mode for α = 0°, 22.5°, and 45°, the intermittent attached gap flow mode for α = 67.5° and 90°, the attached gap flow mode for α = 112.5° and 135°, and the wake interference mode for α = 157.5° and 180°. The RMS lift coefficients of both cylinders are reduced significantly compared with that of a single cylinder, regardless of the position angle of the small cylinder. Although the variation trends of the mean drag and lift coefficients with the position angle of the small cylinder obtained from the two-dimensional (2D) and three-dimensional (3D) simulations are similar, the 2D simulations overestimate the mean drag coefficient, the RMS drag and lift coefficients compared with those obtained from the 3D simulations.

  2. Bearing Capacities of Different-Diameter Concrete-Filled Steel Tubes under Axial Compression

    Directory of Open Access Journals (Sweden)

    Wenjing Wang

    2016-01-01

    Full Text Available The bearing capacities of concrete-filled steel tubes are normally derived through experiments with small-scale specimens, but it is uncertain whether such derivations are appropriate for the much larger components used in practical engineering. This study therefore investigates the effect of different diameters (219, 426, 630, and 820 mm on the axial compression of short concrete columns in steel (Q235 tubes. It is found that the peak nominal stress decreases with increasing specimen size and that the axial bearing capacity is determined by three separate components: the cylinder compressive strength of the concrete, the improvement in strength due to the confining effect of the steel tube, and the longitudinal strength of the steel tube. At peak load, increases in the specimen diameter reduce the hoop stresses in the steel tube, thereby reducing the strengthening effect of confinement. Vertical stress in the steel tube is increased with diameter; therefore, the axial bearing capacity of the steel tube is directly related to the specimen size. Size effect coefficients for these three aspects of bearing capacity are defined and used to develop a size-dependent model for predicting the axial bearing capacity of large, concrete-filled steel tubes. The model is then validated against experimental data.

  3. The distribution of height and diameter in random non-plane binary trees

    CERN Document Server

    Broutin, Nicolas

    2010-01-01

    This study is dedicated to precise distributional analyses of the height of non-plane unlabelled binary trees ("Otter trees"), when trees of a given size are taken with equal likelihood. The height of a rooted tree of size $n$ is proved to admit a limiting theta distribution, both in a central and local sense, as well as obey moderate as well as large deviations estimates. The approximations obtained for height also yield the limiting distribution of the diameter of unrooted trees. The proofs rely on a precise analysis, in the complex plane and near singularities, of generating functions associated with trees of bounded height.

  4. Numerical assessment of ASR recharge using small-diameter wells and surface basins

    Science.gov (United States)

    Händel, Falk; Liu, Gaisheng; Dietrich, Peter; Liedl, Rudolf; Butler, James J.

    2014-09-01

    Aquifer storage and recovery (ASR) methods are increasingly used to overcome the temporal imbalance between water demand and availability. Common ASR recharge methods utilize large-diameter injection wells or surface infiltration basins and trenches, and can be costly to implement. A new low-cost ASR recharge method is currently being developed. This approach is based on recharge via gravity in small-diameter wells installed with direct-push (DP) technology. Numerical modeling is used here to assess the potential of this new approach under conditions commonly faced in field settings. The primary objective is to investigate if a battery of small-diameter DP wells can serve as a viable alternative to a surface basin under typical field conditions, while the secondary objective is to assess which subsurface parameters have the greatest control on DP well performance. Simulation results indicate that gravity recharge via small-diameter wells appears to have a distinct advantage over recharge via surface infiltration basins. For example, two 0.05-m shallow vadose-zone wells with 9-m screens can recharge water at a greater rate than a 60 m2 basin. Also, results reveal that, contrary to an infiltration basin, the recharge rate in a DP well has a much stronger dependence on the horizontal component of hydraulic conductivity than on the vertical component. Moreover, near-surface layers of low hydraulic conductivity, which can significantly reduce the recharge capacity of a surface basin, have a relatively small impact on the recharge capacity of a well as long as a significant portion of the well screen is installed below those layers. Given that installation and operation costs can be low in comparison to common ASR recharge methods, this new approach appears to have great potential for recharging good quality water in shallow unconsolidated aquifers. A field investigation has recently been initiated to follow up the findings of this simulation assessment.

  5. Piston diameter in stapes surgery. Does it have a bearing?

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2014-01-01

    Full Text Available Aims and Objectives: This prospective randomized controlled trial was done to study the effect of piston diameter on hearing outcomes after stapedotomy. Materials and Methods: All the patients diagnosed to have otosclerosis were included in the study. A total of 52 patients were studied ranging in age from 18 to 50 years. The subjects were randomized into two groups, that is, 0.4 mm piston (group A and 0.6 mm piston (group B. The subjects were taken up for small fenestra stapedotomy using either a 0.4 or 0.6 mm piston. The main outcome measures were hearing improvement, air-bone gap closure, and overclosure of air-bone gap. Results: There was no statistical difference in hearing improvement in two different piston diameters, 0.4 and 0.6 mm at speech frequencies. In group A, the air-bone gap improvement in the third follow-up was not significant (P > 0.05, whereas group B showed a statistically significant improvement (P = 0.003. The mean overclosure of air-bone gap was better in patients with 0.4 mm piston at speech frequencies and also at 250 Hz. Significantly, overclosure of air-bone gap at higher frequencies (4 and 8 KHz was seen only with a smaller sized piston. (0.4 mm. Discussion: We analyzed the effect of piston diameter on the hearing results after small fenestra stapedotomy by using similar surgical procedure and similar prosthesis in all patients. Conclusion: There is evidence to suggest that 0.4 mm piston may be better suited for providing optimum hearing results.

  6. A solar cycle lengthwise series of solar diameter measurements

    Science.gov (United States)

    Penna, J. L.; Andrei, A. H.; Boscardin, S. C.; Neto, E. Reis; d'Ávila, V. A.

    2010-02-01

    The measurements of the solar photospheric diameter rank among the most difficult astronomic observations. Reasons for this are the fuzzy definition of the limb, the SNR excess, and the adverse daytime seeing condition. As a consequence there are very few lengthy and consistent time series of such measurements. Using modern techniques, just the series from the IAG/USP and from Calern/OCA span more than one solar cycle. The Rio de Janeiro Group observations started in 1997, and therefore in 2008 one complete solar cycle time span can be analyzed. The series shares common principles of observation and analysis with the ones afore mentioned, and it is complementary on time to them. The distinctive features are the larger number of individual points and the improved precision. The series contains about 25,000 single observations, evenly distributed on a day-by-day basis. The typical error of a single observation is half an arc-second, enabling us to investigate variations at the expected level of tens of arc-second on a weekly basis. These features prompted to develop a new methodology for the investigation of the heliophysical scenarios leading to the observed variations, both on time and on heliolatitude. The algorithms rely on running averages and time shifts to derive the correlation and statistical incertitude for the comparison of the long term and major episodes variations of the solar diameter against activity markers. The results bring support to the correlation between the diameter variation and the solar activity, but evidentiating two different regimens for the long term trend and the major solar events.

  7. Mesiodistal crown diameters of permanent dentition in schoolchildren from Lima

    OpenAIRE

    Pineda-Mejia, Martha; Departamento Académico de Estomatología Rehabilitadora, Facultad Odontología de la Universidad Nacional Mayor de San Marco, Perú.; Petkova- Gueorguieva, Marieta; Facultad Odontología de la Universidad Nacional Mayor de San Marcos.

    2015-01-01

    The purpose of this study was to determine the size of mesiodistal diameters of permanent teeth in a school population of the city of Lima, to analyze the differences between homologous teeth, sexual dimorphism of permanent teeth as well as the degree of variability of the measurements. Methodology: The study was conducted on 400 students of mestizos (200 men and 200 women) 10 to 12 years, from three schools in the districts of la Victoria and Barrios Altos, Lima city. The procedure was perfo...

  8. Economic strategies of plant absorptive roots vary with root diameter

    Science.gov (United States)

    Kong, D. L.; Wang, J. J.; Kardol, P.; Wu, H. F.; Zeng, H.; Deng, X. B.; Deng, Y.

    2016-01-01

    Plant roots typically vary along a dominant ecological axis, the root economics spectrum, depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root economic strategies differ with increasing root diameter. To test this hypothesis, we used seven plant species (a fern, a conifer, and five angiosperms from south China) for which we separated absorptive roots into two categories: thin roots (thickness of root cortex plus epidermis perspective on our understanding of the root economics spectrum.

  9. Impact damage in small diameter graphite/epoxy composite struts

    Science.gov (United States)

    Chen, G.-S.; Bidinger, G. M.; Cho, S.; Lou, M. C.

    1992-01-01

    An investigation was performed to study impact induced damage in small-diameter struts made of a composite material with a brittle matrix system. The major focus is on characterizing the impact behavior associated with the barely visible damage. An experimental procedure including ultrasonic inspection, instrumented impact testing, and delamination buckling and residual strength measurements is presented. From the ultrasonic inspection, it is found that for the strut specimens under investigation, the impact energy level for barely visible damage threshold is above that of the internal damage threshold. A 60- to 65-percent reduction in compressive strength was typical for struts subjected to the barely visible impact damage threshold.

  10. Twist Neutrality and the Diameter of the Nucleosome Core Particle

    DEFF Research Database (Denmark)

    Bohr, Jakob; Olsen, Kasper

    2012-01-01

    The diameter of the nucleosome core particle is the same for all the eukaryotes. Here we discuss the possibility that this selectiveness is consistent with a propensity for twist neutrality, in particular, for the double helical DNA to stay rotationally neutral when strained. Reorganization of DNA...... cannot be done without some level of temporal tensile stress, and as a consequence chiral molecules, such as helices, will twist under strain. The requirement that the nucleosome, constituting the nucleosome core particle and linker DNA, has a vanishing strain-twist coupling leads to a requirement...

  11. Aharonov—Bohm Oscillations in Small Diameter Bi Nanowires

    Science.gov (United States)

    Konopko, L.

    The Aharonov-Bohm effect (AB) exists in cylindrical wires as the magnetoresistance (MR) oscillations with a period ΔB that is proportional to Φ0 / S, where Φ0 = h / e is the flux quantum and S is the wire cross section. The AB-type longitudinal MR oscillations with period ΔB = Φ0 / S caused by electrons undergoing continuous grazing incidence at the wire wall have been observed previously at 4.2 K in single bismuth nanowires with a diameter 0. 2 Spivak theory.

  12. A curved-grid gas proportional scintillation counter instrumented with a 25-mm active-diameter photosensor

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, C.M.B.; Morgado, R.E.; Santos, J.M.F. dos E-mail: jmf@gian.fis.uc.pt; Conde, C.A.N

    2004-04-21

    The curved-grid technique provides a simple method to compensate for the variation in solid angle viewed by the PMT in large-area gas proportional scintillation counters (GPSC), improving their performance. The scintillation region is delimited by a planar grid and a curved one, whose shape is calculated to produce a radially increasing scintillation yield, compensating for the decrease in the solid angle. In this work, we applied this technique to a GPSC instrumented with a PMT having a 25-mm diameter photocathode. The maximum ratio of the detector entrance window to the photocathode diameter thus far achieved, without significant performance degradation, is 1.

  13. STUDY ON RECIPROCATING SEALS FOR A LARGER DIAMETER AXIAL PISTON

    Institute of Scientific and Technical Information of China (English)

    Yang Jian; Yang Huayong; Xu Bing

    2004-01-01

    Sealing performance of the reciprocating seals on a larger diameter (100 mm in diameter ) axial piston is theoretically investigated.Based on the characteristics of the clearance flow between the seal and the piston, reasonable boundary conditions for Navier-Stokes equations are determined and the equations are modified, so that the final equations can describe the real flow state of the clearance flow.Through combining the final equations with finite element method, the pressure distributions within the clearance field during the reciprocating motion of the piston and the leakage rate with the pressure are studied.The deflections of the seal which affect sealing performance are calculated as well.Sealing performance of piston seals using oil as the working liquid is compared with using water.It is concluded that the seal using water as the working liquid is under dry friction, which cannot be dealt with the theory of fluid mechanics.The seal structure is only acceptable using oil as the working liquid..

  14. Measuring angular diameter distances of strong gravitational lenses

    CERN Document Server

    Jee, Inh; Suyu, Sherry H

    2014-01-01

    The distance-redshift relation plays a fundamental role in constraining cosmological models. In this paper, we show that measurements of positions and time delays of strongly lensed images of a background galaxy, as well as those of the velocity dispersion and mass profile of a lens galaxy, can be combined to extract the angular diameter distance of the lens galaxy. Physically, as the velocity dispersion and the time delay give a gravitational potential ($GM/r$) and a mass ($GM$) of the lens, respectively, dividing them gives a physical size ($r$) of the lens. Comparing the physical size with the image positions of a lensed galaxy gives the angular diameter distance to the lens. A mismatch between the exact locations at which these measurements are made can be corrected by measuring a local slope of the mass profile. We expand on the original idea put forward by Paraficz and Hjorth, who analyzed singular isothermal lenses, by allowing for an arbitrary slope of a power-law spherical mass density profile, an ex...

  15. The Use of Narrow Diameter Implants in the Molar Area

    Directory of Open Access Journals (Sweden)

    M. Saad

    2016-01-01

    Full Text Available Implant rehabilitations in the posterior jaw are influenced by many factors such as the condition of the remaining teeth, the force factors related to the patient, the quality of the bone, the maintenance of the hygiene, the limited bone height, the type and extent of edentulism, and the nature of the opposing arch. The gold standard is to place a regular diameter implant (>3.7 mm or a wide one to replace every missing molar. Unfortunately, due to horizontal bone resorption, this option is not possible without lateral bone augmentation. In this situation, narrow diameter implant (NDI < 3.5 mm could be the alternative to lateral bone augmentation procedures. This paper presents a clinical study where NDIs were used for the replacement of missing molars. They were followed up to 11 years. Special considerations were observed and many parameters were evaluated. NDI could be used to replace missing molar in case of moderate horizontal bone resorption if strict guidelines are respected. Yet, future controlled prospective clinical trials are required to admit their use as scientific evidence.

  16. Tunable engineered skin mechanics via coaxial electrospun fiber core diameter.

    Science.gov (United States)

    Blackstone, Britani Nicole; Drexler, Jason William; Powell, Heather Megan

    2014-10-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo.

  17. Diameter of titanium nanotubes influences anti-bacterial efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Ercan, Batur; Taylor, Erik; Webster, Thomas J [School of Engineering, Brown University, Providence, RI 02917 (United States); Alpaslan, Ece, E-mail: thomas_webster@brown.edu [Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul (Turkey)

    2011-07-22

    Bacterial infection of in-dwelling medical devices is a growing problem that cannot be treated by traditional antibiotics due to the increasing prevalence of antimicrobial resistance and biofilm formation. Here, due to changes in surface parameters, it is proposed that bacterial adhesion can be prevented through nanosurface modifications of the medical device alone. Toward this goal, titanium was created to possess nanotubular surface topographies of highly controlled diameters of 20, 40, 60, or 80 nm, sometimes followed by heat treatment to control chemistry and crystallinity, through a novel anodization process. For the first time it was found that through the control of Ti surface parameters including chemistry, crystallinity, nanotube size, and hydrophilicity, significantly changed responses of both Staphylococcus epidermidis and Staphylococcus aureus (pathogens relevant for orthopaedic and other medical device related infections) were measured. Specifically, heat treatment of 80 nm diameter titanium tubes produced the most robust antimicrobial effect of all surface treatment parameters tested. This study provides the first step toward understanding the surface properties of nano-structured titanium that improve tissue growth (as has been previously observed with nanotubular titanium), while simultaneously reducing infection without the use of pharmaceutical drugs.

  18. Algorithms for the extraction of various diameter vessels.

    Science.gov (United States)

    Tremblais, B; Capelle-Laize, A S; Augereau, B

    2007-01-01

    In this communication we propose a new and automatic strategy for the multi-scale extraction of vessels. The objective is to obtain a good representation of the vessels. That is to say a precise characterization of their centerlines and diameters. The adopted solution requires the generation of an image scale-space in which the various levels of details allow to process arteries of any diameter. The proposed method is implemented using the Partial Differential Equations (PDE) and differential geometry formalisms. The differential geometry allows, by the computation of a new valley response, to characterize the centerlines of vessels as well as the bottom lines of the valleys of the image surface. The information given by the centerlines and valley response at different scales are used to obtain the 2D multi-scale centerlines of the arteries. To that purpose, we construct a multi-scale adjacency graph which permits to keep the K strongest detections. Then, the detection we obtain is coded as an attributed graph. The suggested algorithm is applied in the scope of two kinds of angiograms: coronaries and retinal angiograms.

  19. Stellar Diameters and Temperatures II. Main Sequence K & M Stars

    CERN Document Server

    Boyajian, Tabetha S; van Belle, Gerard; McAlister, Harold A; Brummelaar, Theo A ten; Kane, Stephen R; Muirhead, Phil; Jones, Jeremy; White, Russel; Schaefer, Gail; Ciardi, David; Henry, Todd; López-Morales, Mercedes; Ridgway, Stephen; Gies, Douglas; Jao, Wei-Chun; Rojas-Ayala, Bárbara; Parks, J Robert; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H; Farrington, Chris; Goldfinger, P J; Berger, David H

    2012-01-01

    We present interferometric diameter measurements of 21 K- and M- dwarfs made with the CHARA Array. This sample is enhanced by literature radii measurements to form a data set of 33 K-M dwarfs with diameters measured to better than 5%. For all 33 stars, we compute absolute luminosities, linear radii, and effective temperatures (Teff). We develop empirical relations for \\simK0 to M4 main- sequence stars between the stellar Teff, radius, and luminosity to broad-band color indices and metallicity. These relations are valid for metallicities between [Fe/H] = -0.5 and +0.1 dex, and are accurate to \\sim2%, \\sim5%, and \\sim4% for Teff, radius, and luminosity, respectively. Our results show that it is necessary to use metallicity dependent transformations to convert colors into stellar Teff's, radii, and luminosities. We find no sensitivity to metallicity on relations between global stellar properties, e.g., TEFF-radius and TEFF-luminosity. Robust examinations of single star TEFF's and radii compared to evolutionary m...

  20. COMPLICATIONS RELATED TO GASTRIC BYPASS PERFORMED WITH DIFFERENT GASTROJEJUNAL DIAMETERS

    Science.gov (United States)

    SAMPAIO-NETO, José; BRANCO-FILHO, Alcides José; NASSIF, Luis Sérgio; BROSKA, Anne Caroline; KAMEI, Douglas Jun; NASSIF, André Thá

    2016-01-01

    ABSTRACT Background: Among the options for surgical treatment of obesity, the most widely used has been the Roux-en-Y gastric bypass. The gastrojejunal anastomosis can be accomplished in two ways: handsewn or using circular and linear stapled. The complications can be divided in early and late. Aim: To compare the incidence of early complications related with the handsewn gastrojejunal anastomosis in gastric bypass using Fouchet catheter with different diameters. Method: The records of 732 consecutive patients who had undergone the bypass were retrospectively analyzed and divided in two groups, group 1 with 12 mm anastomosis (n=374), and group 2 with 15 mm (n=358). Results: The groups showed anastomotic stenosis with rates of 11% and 3.1% respectively, with p=0.05. Other variables related to the anastomosis were also analyzed, but without statistical significance (p>0.05). Conclusion: The diameter of the anastomosis of 15 mm was related with lower incidence of stenosis. It was found that these patients had major bleeding postoperatively and lower surgical site infection, and in none was observed presence of anastomotic leak. PMID:27683767

  1. CT dose equilibration and energy absorption in polyethylene cylinders with diameters from 6 to 55 cm

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinhua; Zhang, Da; Liu, Bob, E-mail: bliu7@mgh.harvard.edu [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

    2015-06-15

    ratios changed with beam aperture and phantom axis but were insensitive to tube voltage. H(L) was insensitive to tube voltage and CT scanner model. As phantom diameter increased from 6 to 55 cm, E{sub in}/E generally decreased but asymptotically approached constant levels on the peripheral axes of large phantoms. The curve of E{sub in}/E versus scan length was almost identical to that of H(L). Similarly, E{sub out}/E increased with scan length and asymptotically approached the equilibrium for large scan lengths. E{sub out}/D{sub eq} was much less than the equilibrium length L{sub eq} where H(L) = 0.98, even with scan lengths much larger than L{sub eq}. Conclusions: The polyethylene phantom designed by ICRU Report No. 87 Committee and AAPM Task Group 200 is adequately long for assessing the midpoint dose and its equilibration in CT scanning. The short-to-long phantom dose ratios and the H(L) data provided in this paper allow easy evaluations of the midpoint dose, longitudinal dose distribution, and energy absorption in polyethylene phantoms. The results of dose equilibration and energy absorption presented herein may be insightful for the clinical CT scans with various subject sizes and scan lengths.

  2. Are hydrophones of diameter 0.5 mm small enough to characterise diagnostic ultrasound equipment?

    Science.gov (United States)

    Smith, R A

    1989-11-01

    A basic requirement for making measurements of medical ultrasonic fields using small sensors is that the sensor should be smaller than the ultrasonic wavelength. Until recently, the smallest commercially-available PVDF membrane hydrophone sensor had a diameter of 0.5 mm, which is larger that the wavelength in water for frequencies above 3 MHz. Thus many measurements have been made with hydrophones which are strictly too large. In this situation, averaging of the acoustic pressure over the active element can cause an underestimate of the spatial-peak acoustic pressure level. In the past, this error was estimated using theoretical models of the beam profile. However, these models make basic assumptions about both the ultrasonic field and the directional response of the hydrophone--assumptions which may not be valid in all diagnostic ultrasonic fields. GEC-Marconi membrane hydrophones with diameters as small as 0.1 mm have now been used to check these theories for diagnostic fields. This paper shows that the error resulting from the use of too large a hydrophone can be up to three times that predicted by current theories. Possible new correction methods are discussed for use in some situations. In other cases the errors can only be reduced by using these new hydrophones, particularly when the acoustic waveform is distorted by nonlinear propagation.

  3. A modified force-balance model for prediction of bubble departure diameter in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Sugrue, R., E-mail: rsugrue@mit.edu; Buongiorno, J.

    2016-08-15

    Highlights: • Existing bubble departure models were tested against various experimental databases. • General experimental trends were captured correctly but give large average errors. • A modified bubble departure model is proposed and tested against these databases. - Abstract: Experimental data by Sugrue et al., Klausner et al., Zeng et al., Prodanovic et al., and Situ et al. for bubble departure diameter in subcooled flow boiling in a wide range of orientation angle, subcooling, heat flux, mass flux, and pressure conditions were used to assess the predictive accuracy of the mechanistic force-balance models of Klausner et al. and Yun et al. The results suggested that both models capture the experimental trends correctly, but exhibit large average errors and standard deviations, i.e. 85.5% (σ = 49.7%) and 43.9% (σ = 23.1%) for Klausner’s and Yun’s models, respectively. Since the cube of the bubble departure diameter is used in subcooled flow boiling heat transfer models, such errors are unacceptable, and underscore the need for greater accuracy in predictions. Therefore, the databases were used to (i) identify the dominant forces determining bubble departure at various operating conditions, and (ii) optimize the empirical coefficients describing those forces in Klausner’s model. The modified model considerably lowers prediction error to 22.4% (σ = 19.9%) for all data considered. Application of the modified model is demonstrated for the subcooled flow boiling conditions present in the hot channel of a typical Pressurized Water Reactor (PWR).

  4. Sealing vessels up to 7 mm in diameter solely with ultrasonic technology

    Directory of Open Access Journals (Sweden)

    Timm RW

    2014-07-01

    Full Text Available Richard W Timm, Ryan M Asher, Karalyn R Tellio, Alissa L Welling, Jeffrey W Clymer, Joseph F Amaral Ethicon Inc., Cincinnati, OH, USA Introduction: Ultrasonic energy is a mainstay in the armamentarium of surgeons, providing multifunctionality, precision, and control when dissecting and sealing vessels up to 5 mm in diameter. Historically, the inability to seal vessels in the 5–7 mm range has been perceived as an inherent limitation of ultrasonic technology. The purpose of this study was to evaluate sealing of vessels up to 7 mm in diameter with an ultrasonic device that modulates energy delivery during the sealing period. Methods: In ex vivo benchtop and in vivo acute and survival preclinical models, a new ultrasonic device, Harmonic ACE®+7 Shears (Harmonic 7, was compared with advanced bipolar devices in sealing vessels 1–7 mm in diameter with respect of burst pressure, seal reliability, and seal durability. Lateral thermal damage and transection time were also evaluated. Results: Ex vivo tests of Harmonic 7 demonstrated significantly greater median burst pressures than an advanced bipolar device both for vessels <5 mm in diameter (1,078 mmHg and 836 mmHg, respectively, P=0.046 and for those in the range of 5–7 mm (1,419 mmHg and 591 mmHg, P<0.001. In vivo tests in porcine and caprine models demonstrated similar rates of hemostasis between Harmonic 7 and advanced bipolar devices, with high success rates at initial transection and seal durability of 100% after a 30-day survival period. Conclusion: Sealing 5–7 mm vessels is not a limitation of the type of energy used but of how energy is delivered to tissue. These studies document the ability of ultrasonic energy alone to reliably seal large vessels 5–7 mm in diameter, with significantly greater burst pressure observed in in vitro studies than those observed with an advanced bipolar technology when energy delivery is modulated during the sealing cycle. Furthermore, the seals created in

  5. Pade interpolation by F-polynomials and transfinite diameter

    CERN Document Server

    Coman, Dan

    2011-01-01

    We define $F$-polynomials as linear combinations of dilations by some frequencies of an entire function $F$. In this paper we use Pade interpolation of holomorphic functions in the unit disk by $F$-polynomials to obtain explicitly approximating $F$-polynomials with sharp estimates on their coefficients. We show that when frequencies lie in a compact set $K\\subset\\mathbb C$ then optimal choices for the frequencies of interpolating polynomials are similar to Fekete points. Moreover, the minimal norms of the interpolating operators form a sequence whose rate of growth is determined by the transfinite diameter of $K$. In case of the Laplace transforms of measures on $K$, we show that the coefficients of interpolating polynomials stay bounded provided that the frequencies are Fekete points. Finally, we give a sufficient condition for measures on the unit circle which ensures that the sums of the absolute values of the coefficients of interpolating polynomials stay bounded.

  6. Lasering in a Waveguide with Scatterers in Diameter 20 nm

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-Xu; LIU Jun-Ye; ZHANG Jia-Hua; DOU Kai

    2004-01-01

    We report random lasing achieved in a MEH-PPV/glass waveguide with the TiO2 scatterers in diameter 20nm that is significantly smaller than submicrometre of TiO2 scatterers in the films or suspensions previously reported on random lasing. The spectral lines are dramatically narrowed by almost two orders of magnitude compared with those excited by a xenon lamp. The amplified spontaneous emission is identified as the dominant mechanism in our system. Light localization might be achieved in a broad class of random materials based on the features of the mean free path l* = 5.4 × 105 nm, kl* > 1 and the Thouless number 6.73 × 10-5 with k being the wave number.

  7. Seismic fragility test of a 6-inch diameter pipe system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W. P.; Onesto, A. T.; DeVita, V.

    1987-02-01

    This report contains the test results and assessments of seismic fragility tests performed on a 6-inch diameter piping system. The test was funded by the US Nuclear Regulatory Commission (NRC) and conducted by ETEC. The objective of the test was to investigate the ability of a representative nuclear piping system to withstand high level dynamic seismic and other loadings. Levels of loadings achieved during seismic testing were 20 to 30 times larger than normal elastic design evaluations to ASME Level D limits would permit. Based on failure data obtained during seismic and other dynamic testing, it was concluded that nuclear piping systems are inherently able to withstand much larger dynamic seismic loadings than permitted by current design practice criteria or predicted by the probabilistic risk assessment (PRA) methods and several proposed nonlinear methods of failure analysis.

  8. NEOWISE diameters and albedos: now available on PDS!

    Science.gov (United States)

    Masiero, Joseph R.; Mainzer, Amy K.; Bauer, James M.; Cutri, Roc M.; Grav, Tommy; Kramer, Emily A.; Nugent, Carolyn; Sonnett, Sarah M.; Stevenson, Rachel; Wright, Edward L.

    2016-10-01

    We present the recent PDS release of minor planet physical property data from the WISE/NEOWISE fully cryogenic, 3-band cryo, and post-cryo surveys as well as the first year of the NEOWISE-Reactivation survey. This release includes 165,865 diameters, visible albedos, near-infrared albedos, and/or beaming parameters for 140,493 unique minor planets. The published data include near-Earth asteroids, Main Belt asteroids, Hildas, Jupiter Trojans, Centaurs, active Main Belt objects and irregular satellites of Jupiter and Saturn. We provide an overview of the available data and discuss the key features of the PDS data set. The data are available online at: http://sbn.psi.edu/pds/resource/neowisediam.html.

  9. Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER

    CERN Document Server

    Cruzalèbes, P; Rabbia, Y; Sacuto, S; Chiavassa, A; Pasquato, E; Plez, B; Eriksson, K; Spang, A; Chesneau, O

    2013-01-01

    Thanks to their large angular dimension and brightness, red giants and supergiants are privileged targets for optical long-baseline interferometers. Sixteen red giants and supergiants have been observed with the VLTI/AMBER facility over a two-years period, at medium spectral resolution (R=1500) in the K band. The limb-darkened angular diameters are derived from fits of stellar atmospheric models on the visibility and the triple product data. The angular diameters do not show any significant temporal variation, except for one target: TX Psc, which shows a variation of 4% using visibility data. For the eight targets previously measured by Long-Baseline Interferometry (LBI) in the same spectral range, the difference between our diameters and the literature values is less than 5%, except for TX Psc, which shows a difference of 11%. For the 8 other targets, the present angular diameters are the first measured from LBI. Angular diameters are then used to determine several fundamental stellar parameters, and to loca...

  10. Experimental study on the influence of wire diameter on the internal flow behaviour of woven metal screens

    Science.gov (United States)

    Peng, Y. B.; Xu, G. Q.; Luo, X.; Li, H. W.; Liu, Y. P.

    2017-01-01

    Sintered woven wire mesh structures are a classic porous medium. In this paper, we examined the internal flow behaviours of sintered metal wire mesh structures with 0.215mm diameter wires with different porosities. Following previous research results, the influence of woven mesh wire diameter on material penetrating quality was studied. The air that was applied by the gas source was used to investigate structure performance. The Reynolds numbers of the inlet changed from 8.2 to 66.1. The pressures and flow rate at the inlet and outlet were obtained to calculate the permeability and inertia coefficient of each specimen, as well as the friction factors. The experiment results showed that permeability increased and the inertia coefficient decreased as wire diameter increased. Moreover, structures with large wire diameters (d s = 0.215mm) showed better penetrating quality at the same porosity levels. Increases in pressure drop kept pace with increases in diameter. The friction factor decreased as the Reynolds number increased, and tended to be constant.

  11. Maximum diameter of the rod-shaped specimen for transmission electron microtomography without the 'missing wedge'

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Mitsuro [Department of Macromolecular Science and Engineering, Graduate School of Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585 (Japan); Research and Development Department, Nitto Analytical Techno-Center Co., Ltd., 1-1-2, Shimohozumi, Ibaraki-city, Osaka 567-8680 (Japan); Kawase, Noboru [Research and Development Department, Nitto Analytical Techno-Center Co., Ltd., 1-1-2, Shimohozumi, Ibaraki-city, Osaka 567-8680 (Japan); Kaneko, Takeshi [Department of Macromolecular Science and Engineering, Graduate School of Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585 (Japan); Toh, Shoichi; Matsumura, Syo [Research Laboratory of High-Voltage Electron Microscope, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Jinnai, Hiroshi [Department of Macromolecular Science and Engineering, Graduate School of Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585 (Japan)], E-mail: hjinnai@kit.ac.jp

    2008-02-15

    In our recent study, the complete rotation of a rod-shaped specimen during transmission electron microscopy (TEM) has been successfully carried out, yielding a truly quantitative three-dimensional (3D) structure of a ZrO{sub 2}/polymer nano-composite. This result allows the further development of transmission electron microtomography (TEMT) for materials science. The diameter of the rod-shaped specimen was about 150 nm, which may not be statistically large enough to evaluate structural parameters, e.g., volume fraction of Zr nano-particles. Thus, it is preferable to image rods with larger diameters in 3D. In this study, several rod-shaped specimens whose diameters ranged from 150 to 530 nm were subjected to the 'distortion-free TEMT'. The maximum diameters, l, observable under 200 and 300 kV-TEMTs were, respectively, 460-470 and 600-670 nm (corresponding the maximum relative diameters, l/{lambda} ({lambda}: mean free path), were ca. 2.2 and 2.7-3.0)

  12. Microbes make average 2 nanometer diameter crystalline UO2 particles.

    Science.gov (United States)

    Suzuki, Y.; Kelly, S. D.; Kemner, K. M.; Banfield, J. F.

    2001-12-01

    It is well known that phylogenetically diverse groups of microorganisms are capable of catalyzing the reduction of highly soluble U(VI) to highly insoluble U(IV), which rapidly precipitates as uraninite (UO2). Because biological uraninite is highly insoluble, microbial uranyl reduction is being intensively studied as the basis for a cost-effective in-situ bioremediation strategy. Previous studies have described UO2 biomineralization products as amorphous or poorly crystalline. The objective of this study is to characterize the nanocrystalline uraninite in detail in order to determine the particle size, crystallinity, and size-related structural characteristics, and to examine the implications of these for reoxidation and transport. In this study, we obtained U-contaminated sediment and water from an inactive U mine and incubated them anaerobically with nutrients to stimulate reductive precipitation of UO2 by indigenous anaerobic bacteria, mainly Gram-positive spore-forming Desulfosporosinus and Clostridium spp. as revealed by RNA-based phylogenetic analysis. Desulfosporosinus sp. was isolated from the sediment and UO2 was precipitated by this isolate from a simple solution that contains only U and electron donors. We characterized UO2 formed in both of the experiments by high resolution-TEM (HRTEM) and X-ray absorption fine structure analysis (XAFS). The results from HRTEM showed that both the pure and the mixed cultures of microorganisms precipitated around 1.5 - 3 nm crystalline UO2 particles. Some particles as small as around 1 nm could be imaged. Rare particles around 10 nm in diameter were also present. Particles adhere to cells and form colloidal aggregates with low fractal dimension. In some cases, coarsening by oriented attachment on \\{111\\} is evident. Our preliminary results from XAFS for the incubated U-contaminated sample also indicated an average diameter of UO2 of 2 nm. In nanoparticles, the U-U distance obtained by XAFS was 0.373 nm, 0.012 nm

  13. Modular Small Diameter Vascular Grafts with Bioactive Functionalities.

    Directory of Open Access Journals (Sweden)

    Meik Neufurth

    Full Text Available We report the fabrication of a novel type of artificial small diameter blood vessels, termed biomimetic tissue-engineered blood vessels (bTEBV, with a modular composition. They are composed of a hydrogel scaffold consisting of two negatively charged natural polymers, alginate and a modified chitosan, N,O-carboxymethyl chitosan (N,O-CMC. Into this biologically inert scaffold two biofunctionally active biopolymers are embedded, inorganic polyphosphate (polyP and silica, as well as gelatin which exposes the cell recognition signal, Arg-Gly-Asp (RGD. These materials can be hardened by exposure to Ca(2+ through formation of Ca(2+ bridges between the polyanions, alginate, N,O-CMC, and polyP (alginate-Ca(2+-N,O-CMC-polyP. The bTEBV are formed by pressing the hydrogel through an extruder into a hardening solution, containing Ca(2+. In this universal scaffold of the bTEBV biomaterial, polycations such as poly(L-Lys, poly(D-Lys or a His/Gly-tagged RGD peptide (three RGD units were incorporated, which promote the adhesion of endothelial cells to the vessel surface. The mechanical properties of the biopolymer material (alginate-Ca(2+-N,O-CMC-polyP-silica revealed a hardness (elastic modulus of 475 kPa even after a short incubation period in CaCl2 solution. The material of the artificial vascular grafts (bTEBVs with an outer size 6 mm and 1.8 mm, and an inner diameter 4 mm and 0.8 mm, respectively turned out to be durable in 4-week pulsatile flow experiments at an alternating pressure between 25 and 100 mbar (18.7 and 75.0 mm Hg. The burst pressure of the larger (smaller vessels was 850 mbar (145 mbar. Incorporation of polycationic poly(L-Lys, poly(D-Lys, and especially the His/Gly-tagged RGD peptide, markedly increased the adhesion of human, umbilical vein/vascular endothelial cells, EA.HY926 cells, to the surface of the hydrogel. No significant effect of the polyP samples on the clotting of human plasma is measured. We propose that the metabolically

  14. First indirect x-ray imaging tests with an 88-mm diameter single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Macrander, A. T. [Argonne

    2017-02-01

    Using the 1-BM-C beamline at the Advanced Photon Source (APS), we have performed the initial indirect x - ray imaging point-spread-function (PSF) test of a unique 88-mm diameter YAG:Ce single crystal of only 100 - micron thickness. The crystal was bonded to a fiber optic plat e (FOP) for mechanical support and to allow the option for FO coupling to a large format camera. This configuration resolution was compared to that of self - supported 25-mm diameter crystals, with and without an Al reflective coating. An upstream monochromator was used to select 17-keV x-rays from the broadband APS bending magnet source of synchrotron radiation. The upstream , adjustable Mo collimators were then used to provide a series of x-ray source transverse sizes from 200 microns down to about 15-20 microns (FWHM) at the crystal surface. The emitted scintillator radiation was in this case lens coupled to the ANDOR Neo sCMOS camera, and the indirect x-ray images were processed offline by a MATLAB - based image processing program. Based on single Gaussian peak fits to the x-ray image projected profiles, we observed a 10.5 micron PSF. This sample thus exhibited superior spatial resolution to standard P43 polycrystalline phosphors of the same thickness which would have about a 100-micron PSF. Lastly, this single crystal resolution combined with the 88-mm diameter makes it a candidate to support future x-ray diffraction or wafer topography experiments.

  15. Small-Diameter PTFE Portosystemic Shunts: Portocaval vs Mesocaval

    Directory of Open Access Journals (Sweden)

    Robert Shields

    1998-01-01

    Full Text Available Fifty-seven patients with failed sclerotherapy received a mesocaval interposition shunt with an externally supported, ringed polytetrafluoroethylene prosthesis of either 10 or 12 mm diameter. Thirty-one patients had Child-Pugh gradeA disease and 26 grade B; all had a liver volume of 1000– 2500 ml. Follow-up ranged from 16 months to 6 years 3 months. Three patients (5 per cent died in the postoperative period. There were two postoperative recurrences of variceal haemorrhage and one recurrent bleed in the second year after surgery. The cumulative shunt patency rate was 95 per cent and the incidence of encephalopathy 9 per cent; the latter was successfully managed by protein restriction and/or lactulose therapy. The actuarial survival rate for the whole group at 6 years was 78 per cent, for those with Child-Pugh grade A 88 per cent and for grade B 67 per cent. Small-lumen mesocaval interposition shunting achieves portal decompression, preserves hepatopetal flow, has a low incidence of shunt thrombosis, prevents recurrent variceal bleeding and is not associated with significant postoperative encephalopathy.

  16. Fabrication of 200 mm Diameter Sintering Body of Skutterudite Thermoelectric Material by Spark Plasma Sintering

    Science.gov (United States)

    Tomida, T.; Sumiyoshi, A.; Nie, G.; Ochi, T.; Suzuki, S.; Kikuchi, M.; Mukaiyama, K.; Guo, J. Q.

    2016-11-01

    Filled skutterudite is a promising material for thermoelectric power generation because its ZT value is relatively high. However, mass production of high-performance thermoelectric materials remains a challenge. This study focused on the sintering process of thermoelectric materials. Large-diameter n-type (Yb or La, Ca, Al, Ga, In)0.8(Co, Fe)4Sb12 skutterudite sintering bodies with a small thickness were successfully produced by the spark plasma sintering (SPS) method. When direct current flows through the thermoelectric sintering body during the SPS pulse, the Peltier effect causes a temperature difference within the sintering body. To eliminate the Peltier effect, an electrical insulating material was inserted between the punch (electrode) and the sintering body. In this way, an n-type La-filled skutterudite sample with a diameter of 200 mm, thickness of 21 mm, and weight of 5 kg was successfully produced. The thermoelectric properties and microstructures of the sample were almost the same throughout the whole sintering body, and the dimensionless figure of merit reached 1.0 at 773 K.

  17. Experimental investigation of commercial small diameter dental implants in porcine mandibular segments.

    Science.gov (United States)

    Hasan, Istabrak; Heinemann, Friedhelm; Schwegmann, Monika; Keilig, Ludger; Stark, Helmut; Bourauel, Christoph

    2017-02-01

    Small diameter (mini) dental implants have become more popular in recent years as alternatives to classical implant treatment in clinical cases with critical bony situations. However, an in-depth scientific analysis of the mechanical and biomechanical effects of small diameter implants has not yet been published. The aim of the present study was to investigate experimentally different commercial mini implants by measuring their displacements under immediate loading. Twelve commercially available mini implants were measured. Implants were inserted into porcine mandibular segments and loaded by means of a predefined displacement of 0.5 mm of the loading system. The implants were loaded at an angle of 30° to the implant long axis using the self-developed biomechanical hexapod measurement system. Implant displacements were registered. The experimental results were compared to the numerical ones from a previous study. Measured implant displacements were within the range of 39-194 μm. A large variation in the displacements was obtained among the different implant systems due to the different designs and thread profiles. Comparing experimental and numerical results, the displacements that were obtained numerically were within the range of 79-347 μm. The different commercial mini implants showed acceptable primary stability and could be loaded immediately after their insertion.

  18. Empirical equations to predict conditions for solid deposition in small diameter pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Papavinasam, S.; Doiron, A.; Revie, W. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Lab

    2007-03-15

    Corrosion of steels is a major concern for the integrity of pipelines. Corrosion is caused by the combined influence of oil, water, carbon dioxide, hydrogen sulfide, temperature, pressure, and flow. Since localized corrosion is one of the more frequent problems, this study investigated how sand affects localized corrosion on an operating carbon and low-alloy steel pipeline. The objective was to determine critical flow rates in smaller diameter pipeline in which solid deposition occurs as a function of pipe position, inclination, and flow rate. Experimental results, video analysis and empirical equations revealed that under high-flow conditions, the sand impinges on the pipe, causing erosion-corrosion. Under low-flow conditions, the sand deposits at localized areas of the pipeline resulting in underfilm corrosion and preventing access of the inhibitor to the surface. The creation of small anode-large cathode areas may also contribute to this higher pitting corrosion rate in the presence of sand. It was also shown that the pipe diameter, inclination, expansion, and fluid flow rate determine whether sand will deposit or not. No guidelines currently exist to predict critical flow below which solid deposition occurs. As such, it is important to predict the conditions at which sand deposits. 6 refs., 2 tabs., 2 figs.

  19. Experimental study on two-phase flow pressure drop in small diameter bends

    Directory of Open Access Journals (Sweden)

    A.T. Autee

    2016-09-01

    Full Text Available Measurement of two-phase flow pressure drop and its prediction across curved tubes and bends is important for the enhancement of the performance and safety of the heat exchangers and flow transmitting devices. The comparative study of some of the available two-phase pressure drop correlations reveals that the predicted values of pressure drops by these leading methods may differ by large. The applicability of these correlations to the small diameter tubes of range 4.0–8.0 mm and different bend angles of the range 90–180° is not fully established. The basic objective of the present experimental investigation is to generate the experimental data to develop the unified correlation applicable for the small diameter tubes of range 4.0–8.0 mm and different bend angles of the range 90–180°. Hence, experimental facility was developed to conduct the experiments to generate the data and to assess the predictive capability of some of the available two-phase pressure drop correlations. It was observed that the correlations considered for comparisons were unable to satisfactorily predict the measured experimental data within the ±50% error bands. A new correlation is developed in terms of curvature multiplier to the straight tube two-phase pressure drop. The correlation is validated with the present measured experimental data. The statistical analysis suggests that correlation shows satisfactory results.

  20. Development of a 5.5 m diameter vertical axis wind turbine, phase 3

    Science.gov (United States)

    Dekitsch, A.; Etzler, C. C.; Fritzsche, A.; Lorch, G.; Mueller, W.; Rogalla, K.; Schmelzle, J.; Schuhwerk, W.; Vollan, A.; Welte, D.

    1982-06-01

    In continuation of development of a 5.5 m diameter vertical axis windmill that consists in conception, building, and wind tunnel testing, a Darrieus rotor windpowered generator feeding an isolated network under different wind velocity conditions and with optimal energy conversion efficiency was designed built, and field tested. The three-bladed Darrieus rotor tested in the wind tunnel was equiped with two variable pitch Savonius rotors 2 m in diameter. By means of separate measures of the aerodynamic factors and the energy consumption, effect of revisions and optimizations on different elements was assessed. Pitch adjustement of the Savonius blades, lubrication of speed reducer, rotor speed at cut-in of generator field excitation, time constant of field excitation, stability conditions, switch points of ohmic resistors which combined with a small electric battery simulated a larger isolated network connected with a large storage battery, were investigated. Fundamentals for the economic series production of windpowered generators with Darrieus rotors for the control and the electric conversion system are presented.

  1. A computational algorithm addressing how vessel length might depend on vessel diameter.

    Science.gov (United States)

    Cai, Jing; Zhang, Shuoxin; Tyree, Melvin T

    2010-07-01

    The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the genus Populus, vessel length is sometimes a linear function of vessel diameter and sometimes an exponential function of vessel diameter within a stem, based on R(2) values. Our results give within-species variation of vessel length versus diameter, and we compare this to between-species variation of mean diameter versus mean length.

  2. Comparison of CT-Determined Pulmonary Artery Diameter, Aortic Diameter, and Their Ratio in Healthy and Diverse Clinical Conditions.

    Directory of Open Access Journals (Sweden)

    Sang Hoon Lee

    Full Text Available The main pulmonary artery diameter (mPA, aortic diameter (Ao, and the mPA/Ao ratio, easily measured using chest computed tomography (CT, provide information that enables the diagnosis and evaluation of cardiopulmonary diseases. Here, we used CT to determine the sex- and age-specific distribution of normal reference values for mPA, Ao, and mPA/Ao ratio in an adult Korean population.Data from non-contrast, ECG-gated, coronary-calcium-scoring CT images of 2,547 individuals who visited the Health Screening Center of the Severance Hospital were analyzed. Healthy individuals (n = 813 included those who do not have hypertension, diabetes, asthma, obstructive lung disease, ischemic heart disease, stroke, smoking, obesity, and abnormal CT findings. Both mPA and Ao were measured at the level of bifurcation of the main pulmonary artery.The mean mPA and Ao were 25.9 mm and 30.0 mm in healthy participants, respectively, while the mean mPA/Ao ratio was 0.87. Medical conditions associated with a larger mPA were male, obesity, smoking history, hypertension, and diabetes. A larger mPA/Ao ratio was associated with female, the obese, non-smoker, normotensive, and normal serum level of lipids, while a smaller mPA/Ao ratio was associated with older age. In healthy individuals, the 90th percentile sex-specific mPA, Ao, and mPA/Ao ratio were, 31.3 mm (95% CI 29.9-32.2, 36.8 mm (95% CI 35.7-37.5, and 1.05 (95% CI 0.99-1.07 in males, and 29.6 mm (95% CI 29.1-30.2, 34.5 mm (95% CI 34.1-34.9, and 1.03 (95% CI 1.02-1.06 in females, respectively.In the Korean population, the mean mPA reference values in male and female were 26.5 mm and 25.8 mm, respectively, while the mean mPA/Ao ratio was 0.87. These values were influenced by a variety of underlying medical conditions.

  3. A Summary of Comet Nuclei Diameters and Dust Photometry from the WISE/NEOWISE Prime Mission

    Science.gov (United States)

    Bauer, James M.; Grav, Tommy; Mainzer, Amy K.; Fernandez, Yanga R.; Kramer, Emily A.; Masiero, Joseph R.; Spahr, Timothy; Nugent, Carolyn; Sonnett, Sarah M.; Meech, Karen Jean; Lisse, Casey M.; Cutri, Roc M.; Walker, Russell G.; Rosser, Joshua; Krings, Phillip; Wright, Edward L.; NEOWISE Team

    2016-10-01

    While the ROSETTA mission has shown us for the first time up-close manifestations of cometary behavior over the course of a comet's complete orbit, and so given us new insight into how to interpret cometary phenomena seen from Earth, even the most basic of properties, the distribution of effective nuclear diameters, is not well understood. Milestone surveys in the infrared are significantly advancing the number of measured comet diameters (e.g. Fernandez et al. 2013). Now with the NEOWISE prime mission data, we have new diameter constraints for 155 cometary nuclei, 55 of which are of long-period. This makes the NEOWISE dataset the largest diameter sample size in a single survey. The dataset also provides information on large-grained dust production via measurements of ɛfρ. These data, in concert with parallel studies regarding the ejection times and size distributions of the dust (Kramer et al. 2016), and the gas production (Bauer et al. 2015), yield a remarkable amount of information regarding the correlations amongst these properties and as a function of comet orbital classification. We will summarize the final results of the NEOWISE prime mission (Mainzer et al. 2011) comet nuclei survey, and provide an overview of what the restarted mission (Mainzer et al. 2014) results are yielding in terms of constraints on dust and gas production at these crucial wavelengths.ReferencesBauer, J.M. et al. (2015), ApJ 814, 85.Kramer et al. (2016) 48th AAS Div. of Planetary Science /EPSC 11th Meeting, Pasadena, CAFernández, Y. R. et al. (2013), Icarus, 226, 1138.Mainzer, A.K., et al. (2011). ApJ 731, 53.Mainzer et al. (2014). ApJ, 792, 30.Acknowledgements: This work makes use of data products from the Wide- field Infrared Survey Explorer, a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration, and data products from NEOWISE, which is a

  4. A relationship between the diameter and the intersection number c2 for a distance-regular graph

    CERN Document Server

    Koolen, Jack H

    2011-01-01

    In this paper we will look at the relationship between the intersection number c2 and its diameter for a distance-regular graph. And also, we give some tools to show that a distance-regular graph with large c2 is bipartite, and a tool to show that if kD is too small then the distance-regular graph has to be antipodal.

  5. Assessing Pain Using the Variation Coefficient of Pupillary Diameter.

    Science.gov (United States)

    Charier, David J; Zantour, Daniel; Pichot, Vincent; Chouchou, Florian; Barthelemy, Jean-Claude M; Roche, Frederic; Molliex, Serge B

    2017-07-13

    Pupillary diameter (PD) varies under the influence of the sympathetic as well as parasympathetic systems, increasing proportionally with pain intensity. Such variations however, should not be confused with pupillary fluctuations, which refer to the fast and permanent PD fluctuations induced by the ongoing interplay between the sympathetic and parasympathetic systems, which we propose to measure using the variation coefficient of PD (VCPD). This study aimed first at correlating PD, PD increase during a contraction, and VCPD, with pain rated using a numeric rating scale (NRS) during obstetrical labor, and then at comparing such correlations with each other. Forty patients were included in the study, and 160 simultaneous ratings (NRS, PD, and VCPD) were taken: 40 in the presence of uterine contractions and 40 in the absence of such contractions, before and 20 minutes after epidural analgesia. VCPD correlates more strongly (r = .77) than PD increase (r = .42) with pain rated using a NRS. The ability of VCPD to predict the occurrence of NRS scores ≥4 during obstetrical labor is .97 (confidence interval, .93-1.0). When measured over 10 seconds during contraction, VCPD correlates more strongly than PD increase with pain rated using the NRS. Such stronger correlation allows for an easy assessment of antinociception-nociception balance. The VCPD allows for an objective assessment of pain in laboring women. It could allow for an easy assessment of pain in noncommunicating patients: newborns or very old patients, patients with serious psychological conditions, assessment during the immediate postoperative period, or in intensive care units. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

  6. Solar Diameter Measurements from Eclipses as a Solar Variability Proxy

    Science.gov (United States)

    Waring Dunham, David; Sofia, Sabatino; Guhl, Konrad; Herald, David Russell

    2015-08-01

    Since thermal relaxation times for the Sun are thousands of years, small variations of the Solar intensity are proportional to small variations of the Solar diameter on decadal time scales. In a combination between observations and theory, reliable values of the relation constant W are known, that allow transformation of historical variations of radius into variations of the solar luminosity. During the past 45 years, members of the International Occultation Timing Association (IOTA) have observed 20 annular and total solar eclipses from locations near the path edges. Baily’s beads, whose occurrence and duration are considerably prolonged as seen from path edge locations, were first timed visually, mostly using projection techniques, but since about 1980, they have been timed mainly from analysis of video recordings. The edge locations have the advantage that most of the beads are defined by the same features in the lunar polar regions that cause the phenomena at each eclipse. Some of the best-observed modern eclipses can be used to assess the accuracy of the results, which are limited mainly by the intensity drop at the Sun’s edge, and the consequent uncertainty in defining the edge. In addition, direct visual contact timings made near the path edges during earlier eclipses, back to 1715, have been found in the literature, and analyzed. Although the observations seem to show small variations, they are only a little larger than the assessed accuracies. The results can be improved with a consistent re-analysis of the observations using the much more accurate lunar profile data that is now available from the Japanese Kaguya and NASA’s LRO lunar orbiter observations. Also, IOTA has plans to observe future eclipses with a variety of techniques that were used in the past, to better assess the accuracies of the different observational methods that have been used, and determine any systematic differences between them.

  7. AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

    2011-01-14

    Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

  8. Integrated spectral study of small angular diameter galactic open clusters

    Science.gov (United States)

    Clariá, J. J.; Ahumada, A. V.; Bica, E.; Pavani, D. B.; Parisi, M. C.

    2017-10-01

    This paper presents flux-calibrated integrated spectra obtained at Complejo Astronómico El Leoncito (CASLEO, Argentina) for a sample of 9 Galactic open clusters of small angular diameter. The spectra cover the optical range (3800-6800 Å), with a resolution of ∼14 Å. With one exception (Ruprecht 158), the selected clusters are projected into the fourth Galactic quadrant (282o < l < 345o) near the Galactic plane (∣b∣ ≤ 9o). We performed simultaneous estimates of foreground interstellar reddening and age by comparing the continuum distribution and line strenghts of the cluster spectra with those of template cluster spectra with known parameters. We thus provide spectroscopic information independent from that derived through color-magnitude diagram studies. We found three clusters (Collinder 249, NGC 4463 and Ruprecht 122) younger than ∼40 Myr, four moderately young ones (BH 92, Harvard 5, Hogg 14 and Pismis 23) with ages within 200-400 Myr, and two intermediate-age ones (Ruprecht 158 and ESO 065-SC07) with ages within 1.0-2.2 Gyr. The derived foreground E(B - V) color excesses vary from around 0.0 in Ruprecht 158 to ∼1.1 in Pismis 23. In general terms, the results obtained show good agreement with previous photometric results. In Ruprecht 158 and BH 92, however, some differences are found between the parameters here obtained and previous values in the literature. Individual spectra of some comparatively bright stars located in the fields of 5 out of the 9 clusters here studied, allowed us to evaluate their membership status. The current cluster sample complements that of 46 open clusters previously studied by our group in an effort to gather a spectral library with several clusters per age bin. The cluster spectral library that we have been building is an important tool to tie studies of resolved and unresolved stellar content.

  9. Reduced power processor requirements for the 30-cm diameter HG ion thruster

    Science.gov (United States)

    Rawlin, V. K.

    1979-01-01

    The characteristics of power processors strongly impact the overall performance and cost of electric propulsion systems. A program was initiated to evaluate simplifications of the thruster-power processor interface requirements. The power processor requirements are mission dependent with major differences arising for those missions which require a nearly constant thruster operating point (typical of geocentric and some inbound planetary missions) and those requiring operation over a large range of input power (such as outbound planetary missions). This paper describes the results of tests which have indicated that as many as seven of the twelve power supplies may be eliminated from the present Functional Model Power Processor used with 30-cm diameter Hg ion thrusters.

  10. CALIFA: a diameter-selected sample for an integral field spectroscopy galaxy survey

    Science.gov (United States)

    Walcher, C. J.; Wisotzki, L.; Bekeraité, S.; Husemann, B.; Iglesias-Páramo, J.; Backsmann, N.; Barrera Ballesteros, J.; Catalán-Torrecilla, C.; Cortijo, C.; del Olmo, A.; Garcia Lorenzo, B.; Falcón-Barroso, J.; Jilkova, L.; Kalinova, V.; Mast, D.; Marino, R. A.; Méndez-Abreu, J.; Pasquali, A.; Sánchez, S. F.; Trager, S.; Zibetti, S.; Aguerri, J. A. L.; Alves, J.; Bland-Hawthorn, J.; Boselli, A.; Castillo Morales, A.; Cid Fernandes, R.; Flores, H.; Galbany, L.; Gallazzi, A.; García-Benito, R.; Gil de Paz, A.; González-Delgado, R. M.; Jahnke, K.; Jungwiert, B.; Kehrig, C.; Lyubenova, M.; Márquez Perez, I.; Masegosa, J.; Monreal Ibero, A.; Pérez, E.; Quirrenbach, A.; Rosales-Ortega, F. F.; Roth, M. M.; Sanchez-Blazquez, P.; Spekkens, K.; Tundo, E.; van de Ven, G.; Verheijen, M. A. W.; Vilchez, J. V.; Ziegler, B.

    2014-09-01

    We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area (CALIFA) survey, a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45'' and 79.2'' and with a redshift 0.005 Mr > -23.1 and over a stellar mass range between 109.7 and 1011.4 M⊙. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of Mr = -19 (or stellar masses CSIC). Publically released data products from CALIFA are made available on the webpage http://www.caha.es/CALIFA

  11. Super stretchable hydrogel achieved by non-aggregated spherulites with diameters <5 nm

    Science.gov (United States)

    Sun, Guoxing; Li, Zongjin; Liang, Rui; Weng, Lu-Tao; Zhang, Lina

    2016-06-01

    The scope of hydrogel applications can be greatly expanded by the improvement of mechanical properties. However, enhancement of nanocomposite hydrogels (NC gels) has been severely limited because the size of crosslinking nanoparticles is too large, at least in one dimension. Here we report a new strategy to synthesize non-aggregated spherulite nanoparticles, with diameters hydrogel. The stress and stretch ratio at rupture of our NC gel are 430 and 121 KPa with only 40-p.p.m. nanoparticle content. The NC gel containing 200-p.p.m. nanoparticles can revert to 90% of its original size after enduring 100-MPa compressive stress. Our results demonstrate that the suppression of nanoparticle size without aggregation helps to establish a super stretchable and high-toughness hydrogel network at very low inorganic content.

  12. Height-diameter relationships of tropical Atlantic moist forest trees in southeastern Brazil

    OpenAIRE

    Marcos Augusto da Silva Scaranello; Luciana Ferreira Alves; Simone Aparecida Vieira; Plinio Barbosa Camargo; Carlos Alfredo Joly; Luiz Antônio Martinelli

    2013-01-01

    Site-specific height-diameter models may be used to improve biomass estimates for forest inventories where only diameter at breast height (DBH) measurements are available. In this study, we fit height-diameter models for vegetation types of a tropical Atlantic forest using field measurements of height across plots along an altitudinal gradient. To fit height-diameter models, we sampled trees by DBH class and measured tree height within 13 one-hectare permanent plots established at four altitu...

  13. Bloch-Wave Engineered Submicron Diameter Micropillars with Quality Factors Exceeding 10,000

    DEFF Research Database (Denmark)

    Hofling, S.; Lermer, M.; Gregersen, Niels;

    2011-01-01

    Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed.......Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed....

  14. Comprehensive database of diameter-based biomass regressions for North American tree species

    Science.gov (United States)

    Jennifer C. Jenkins; David C. Chojnacky; Linda S. Heath; Richard A. Birdsey

    2004-01-01

    A database consisting of 2,640 equations compiled from the literature for predicting the biomass of trees and tree components from diameter measurements of species found in North America. Bibliographic information, geographic locations, diameter limits, diameter and biomass units, equation forms, statistical errors, and coefficients are provided for each equation,...

  15. Basic maneuvers for an inspection robot for small diameter gas distribution mains

    NARCIS (Netherlands)

    Dertien, Edwin Christian; Stramigioli, Stefano

    2011-01-01

    This video shows the design of a mechanical structure of a miniature pipe inspection robot (MPR) capable of moving trough very small pipes (up to 41 mm inner diameter) as well as a wide range of diameters (63 to 125 mm outer diameter). The requirement to negotiate bends, T-joints and steep

  16. Basic maneuvers for an inspection robot for small diameter gas distribution mains

    NARCIS (Netherlands)

    Dertien, Edwin; Stramigioli, Stefano

    2011-01-01

    This video shows the design of a mechanical structure of a miniature pipe inspection robot (MPR) capable of moving trough very small pipes (up to 41 mm inner diameter) as well as a wide range of diameters (63 to 125 mm outer diameter). The requirement to negotiate bends, T-joints and steep inclinati

  17. Non-linear height-diameter models for oriental beech (Fagus orientalis Lipsky in the Hyrcanian forests, Iran

    Directory of Open Access Journals (Sweden)

    Ahmadi, K.

    2013-01-01

    Full Text Available The relationship between tree height and diameter is an important element in growth and yield models, in carbon budget and timber volume models, and in the description of stand dynamics. Six non-linear growth functions (i.e. Chapman-Richards, Schnute, Lundqvist/Korf, Weibull, Modified Logistic and Exponential were fitted to tree height-diameter data of oriental beech in the Hyrcanian mixed hardwood forests of Iran. The predictive performance of these models was in the first place assessed by means of different model evaluation criteria such as adjusted R squared (adjR2, root mean square error (RMSE, Akaike information criterion (AIC, mean difference (MD, mean absolute difference (MAD and mean square (MS error criteria. Although each of the six models accounted for approximately 75% of total variation in height, a large difference in asymptotic estimates was observed. Apart from this, the predictive performance of the models was also evaluated by means of cross-validation and by splitting the data into 5-cm diameter classes. Plotting the MD in relation to these diameter at breast height (DBH classes showed for all growth functions, except for the Modified Logistic function, similar mean prediction errors for small- and medium-sized trees. Large-sized trees, however, showed a higher mean prediction error. The Modified Logistic function showed the worst performance due to a large model bias. The Exponential and Lundqvist/Korf models were discarded due to their showing biologically illogical behavior and unreasonable estimates for the asymptotic coefficient, respectively. Considering all the above-mentioned criteria, the Chapman-Richards, Weibull, and Schnute functions provided the most satisfactory height predictions. However, we would recommend the Chapman-Richards function for further analysis because of its higher predictive performance.

  18. Large deviations

    CERN Document Server

    Varadhan, S R S

    2016-01-01

    The theory of large deviations deals with rates at which probabilities of certain events decay as a natural parameter in the problem varies. This book, which is based on a graduate course on large deviations at the Courant Institute, focuses on three concrete sets of examples: (i) diffusions with small noise and the exit problem, (ii) large time behavior of Markov processes and their connection to the Feynman-Kac formula and the related large deviation behavior of the number of distinct sites visited by a random walk, and (iii) interacting particle systems, their scaling limits, and large deviations from their expected limits. For the most part the examples are worked out in detail, and in the process the subject of large deviations is developed. The book will give the reader a flavor of how large deviation theory can help in problems that are not posed directly in terms of large deviations. The reader is assumed to have some familiarity with probability, Markov processes, and interacting particle systems.

  19. Final Report: DoE SBIR Phase 2 Low-Cost Small Diameter NMR Technologies for In-Situ Subsurface Characterization and Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, David Oliver [Vista Clara Inc., Mukilteo, WA (United States)

    2010-09-03

    In this Phase 2 SBIR program, Vista Clara successfully developed and field-tested small diameter NNR logging tools for subsurface characterization and monitoring. This effort involved the design and development surface electronics, a winch with 470ft cable, and three interchangeable downhole probes: a 3.5â diameter borehole NMR probe, a 1.67â diameter borehole NMR probe, and a 2.5â diameter NMR probe that can be deployed using a Geoprobe direct push machine. The 3.5â probe was tested extensively over a 6 week period including 4â to 8â boreholes in Washington, Idaho, Nebraska, Colorado, Kansas, Connecticut and Massachusetts. The field test campaign was highly successful. The 1.67â probe was assembled, tested and calibrated in the laboratory. The 2.5â Geoprobe probe is in final assembly and testing at the time of this report. The completed Phase 2 R&D program has resulted in the first NMR logging tool that can be deployed in boreholes of 4â diameter, the first NMR logging tool that can be deployed in boreholes on 2â diameter, and the first NMR logging tool that can be deployed by a direct push machine. These small diameter tools make NMR logging technically and economically feasible, for the first time. Previously available NMR logging tools were developed for oilfield applications and are prohibitively large and expensive for the majority of near surface groundwater characterization problems.

  20. Variation associated with measurement of retinal vessel diameters at different points in the pulse cycle

    Science.gov (United States)

    Knudtson, M D; Klein, B E K; Klein, R; Wong, T Y; Hubbard, L D; Lee, K E; Meuer, S M; Bulla, C P

    2004-01-01

    Background/aims: To assess the variability in retinal vessel measurements at different points in the pulse cycle. Methods: A healthy white male aged 19 years had 30 digitised images taken at three distinct points in the pulse cycle over a one hour period. A pulse synchronised ear clip trigger device was used to capture images at the desired point in the pulse cycle. Two trained graders measured the retinal vessel diameter of one large arteriole, one large venule, one small arteriole, and one small venule 10 times in each of these 30 images. Results: Within an image, variability was similar between graders, pulse point, and vessel type. Across images taken at the same point in the pulse period, the change from the minimum to maximum measurement was between 6% and 17% for arterioles and between 2% and 11% for venules. In addition, measurements of small vessels had greater changes than large vessels and no point in the pulse period was more variable than another. Ignoring pulse cycle increased variability across images in the large venule, but not in the other vessel types. Mixed effect models were fit for each of the vessel types to determine the greatest source of variability. Controlling for pulse point and grader, the largest source of variability for all four vessels measured was across images, accounting for more than 50% of the total variability. Conclusion: Measurements of large retinal venules is generally less variable than measurements of other retinal vessels. After controlling for pulse point and grader, the largest source of variation is across images. Understanding the components of variability in measuring retinal vessels is important as these techniques are applied in epidemiological studies. PMID:14693774