Multiple piece turbine rotor blade

DOEpatents

Jones, Russell B; Fedock, John A

2013-05-21

A multiple piece turbine rotor blade with a shell having an airfoil shape and secured between a spar and a platform with the spar including a tip end piece. a snap ring fits around the spar and abuts against the spar tip end piece on a top side and abuts against a shell on the bottom side so that the centrifugal loads from the shell is passed through the snap ring and into the spar and not through a tip cap dovetail slot and projection structure.

Asymmetrical field emitter

DOEpatents

Fleming, J.G.; Smith, B.K.

1995-10-10

A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

Near wall cooling for a highly tapered turbine blade

DOEpatents

Liang, George [Palm City, FL

2011-03-08

A turbine blade having a pressure sidewall and a suction sidewall connected at chordally spaced leading and trailing edges to define a cooling cavity. Pressure and suction side inner walls extend radially within the cooling cavity and define pressure and suction side near wall chambers. A plurality of mid-chord channels extend radially from a radially intermediate location on the blade to a tip passage at the blade tip for connecting the pressure side and suction side near wall chambers in fluid communication with the tip passage. In addition, radially extending leading edge and trailing edge flow channels are located adjacent to the leading and trailing edges, respectively, and cooling fluid flows in a triple-pass serpentine path as it flows through the leading edge flow channel, the near wall chambers and the trailing edge flow channel.

Back-to-School Health Tips: Exercise and Sleep

MedlinePlus

... up the same times each day. Keep room temperature on the cool side. A TV or computer in the bedroom can be a distraction. Read More "Back-to-School" Articles Health Tips: Immunizations / Health Tips: Exercise and ...

7. VIEW OF TIP TOP AND PHILLIPS MINES. PHOTO MADE ...

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

7. VIEW OF TIP TOP AND PHILLIPS MINES. PHOTO MADE FROM THE 'NOTTINGHAM' SADDLE VISIBLE IN PHOTOGRAPHS ID-31-3 AND ID-31-6. CAMERA POINTED NORTHEAST TIP TOP IS CLEARLY VISIBLE IN UPPER RIGHT; RUNNING A STRAIGHT EDGE THROUGH THE TRUNK LINE OF SMALL TREE IN LOWER RIGHT THROUGH TRUNK LINE OF LARGER TREE WILL DIRECT ONE TO LIGHT AREA WHERE TIP TOP IS LOCATED; BLACK SQUARE IS THE RIGHT WINDOW ON WEST SIDE (FRONT) OF STRUCTURE. PHILLIPS IS VISIBLE BY FOLLOWING TREE LINE DIAGONALLY THROUGH IMAGE TO FAR LEFT SIDE. SULLIVAN IS HIDDEN IN THE TREE TO THE RIGHT OF PHILLIPS. - Florida Mountain Mining Sites, Silver City, Owyhee County, ID

Comparison of Various Supersonic Turbine Tip Designs to Minimize Aerodynamic Loss and Tip Heating

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Ameri, Ali

2012-01-01

The rotor tips of axial turbines experience high heat flux and are the cause of aerodynamic losses due to tip clearance flows, and in the case of supersonic tips, shocks. As stage loadings increase, the flow in the tip gap approaches and exceeds sonic conditions. This introduces effects such as shock-boundary layer interactions and choked flow that are not observed for subsonic tip flows that have been studied extensively in literature. This work simulates the tip clearance flow for a flat tip, a diverging tip gap and several contoured tips to assess the possibility of minimizing tip heat flux while maintaining a constant massflow from the pressure side to the suction side of the rotor, through the tip clearance. The Computational Fluid Dynamics (CFD) code GlennHT was used for the simulations. Due to the strong favorable pressure gradients the simulations assumed laminar conditions in the tip gap. The nominal tip gap width to height ratio for this study is 6.0. The Reynolds number of the flow is 2.4 x 10(exp 5) based on nominal tip width and exit velocity. A wavy wall design was found to reduce heat flux by 5 percent but suffered from an additional 6 percent in aerodynamic loss coefficient. Conventional tip recesses are found to perform far worse than a flat tip due to severe shock heating. Overall, the baseline flat tip was the second best performer. A diverging converging tip gap with a hole was found to be the best choice. Average tip heat flux was reduced by 37 percent and aerodynamic losses were cut by over 6 percent.

Trailing edge cooling using angled impingement on surface enhanced with cast chevron arrangements

DOEpatents

Lee, Ching-Pang; Heneveld, Benjamin E.; Brown, Glenn E.; Klinger, Jill

2015-05-26

A gas turbine engine component, including: a pressure side (12) having an interior surface (34); a suction side (14) having an interior surface (36); a trailing edge portion (30); and a plurality of suction side and pressure side impingement orifices (24) disposed in the trailing edge portion (30). Each suction side impingement orifice is configured to direct an impingement jet (48) at an acute angle (52) onto a target area (60) that encompasses a tip (140) of a chevron (122) within a chevron arrangement (120) formed in the suction side interior surface. Each pressure side impingement orifice is configured to direct an impingement jet at an acute angle onto an elongated target area that encompasses a tip of a chevron within a chevron arrangement formed in the pressure side interior surface.

Turing mechanism underlying a branching model for lung morphogenesis.

PubMed

Xu, Hui; Sun, Mingzhu; Zhao, Xin

2017-01-01

The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

Sensitivity of collective action to uncertainty about climate tipping points

NASA Astrophysics Data System (ADS)

Barrett, Scott; Dannenberg, Astrid

2014-01-01

Despite more than two decades of diplomatic effort, concentrations of greenhouse gases continue to trend upwards, creating the risk that we may someday cross a threshold for `dangerous' climate change. Although climate thresholds are very uncertain, new research is trying to devise `early warning signals' of an approaching tipping point. This research offers a tantalizing promise: whereas collective action fails when threshold uncertainty is large, reductions in this uncertainty may bring about the behavioural change needed to avert a climate `catastrophe'. Here we present the results of an experiment, rooted in a game-theoretic model, showing that behaviour differs markedly either side of a dividing line for threshold uncertainty. On one side of the dividing line, where threshold uncertainty is relatively large, free riding proves irresistible and trust illusive, making it virtually inevitable that the tipping point will be crossed. On the other side, where threshold uncertainty is small, the incentive to coordinate is strong and trust more robust, often leading the players to avoid crossing the tipping point. Our results show that uncertainty must be reduced to this `good' side of the dividing line to stimulate the behavioural shift needed to avoid `dangerous' climate change.

Effects of Tip Clearance and Casing Recess on Heat Transfer and Stage Efficiency in Axial Turbines

NASA Technical Reports Server (NTRS)

Ameri, A. A.; Steinthorsson, E.; Rigby, David L.

1998-01-01

Calculations were performed to assess the effect of the tip leakage flow on the rate of heat transfer to blade, blade tip and casing. The effect on exit angle and efficiency was also examined. Passage geometries with and without casing recess were considered. The geometry and the flow conditions of the GE-E 3 first stage turbine, which represents a modem gas turbine blade were used for the analysis. Clearance heights of 0%, 1%, 1.5% and 3% of the passage height were considered. For the two largest clearance heights considered, different recess depths were studied. There was an increase in the thermal load on all the heat transfer surfaces considered due to enlargement of the clearance gap. Introduction of recessed casing resulted in a drop in the rate of heat transfer on the pressure side but the picture on the suction side was found to be more complex for the smaller tip clearance height considered. For the larger tip clearance height the effect of casing recess was an orderly reduction in the suction side heat transfer as the casing recess height was increased. There was a marked reduction of heat load and peak values on the blade tip upon introduction of casing recess, however only a small reduction was observed on the casing itself. It was reconfirmed that there is a linear relationship between the efficiency and the tip gap height. It was also observed that the recess casing has a small effect on the efficiency but can have a moderating effect on the flow underturning at smaller tip clearances.

Discovery and Utilization of Nanoscale and Mesoscale Enabling Materials and Processes for Optoelectronics and Electronic Interconnects

DTIC Science & Technology

2003-12-01

Heating and Cooling Device 42 5.2.3 Multiple Tip STM ~ 43 5.2.3.1 Novel Nanomanipulator MM3 43 5.2.3.2 Four Tip STM Assembly 44 5.2.3.3 Vibration ...Analysis of Eddy Current Damping System of Multiple TIP STM " 44 5.2.3.4 Active Vibration Damping System 46 5.3 First Results 47 5.3.1 UHV-SEM...side: Actual device side and top view. 44 46. Setup for the vibration analysis experiment. 45 47. Relaxation of the STM unit, (a) without the eddy

The possible involvement of root-cap mucilage in gravitropism and calcium movement across root tips of Allium cepa L

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.

1986-01-01

Roots of Allium cepa L. grown in aerated water elongate rapidly, but are not graviresponsive. These roots (1) possess extensive columella tissues comprised of cells containing numerous sedimented amyloplasts, (2) lack mucilage on their tips, and (3) are characterized by a weakly polar movement of calcium (Ca) across their tips. Placing roots in humid air correlates positively with the (1) onset of gravicurvature, (2) appearance of mucilage on tips of the roots, and (3) onset of the ability to transport Ca polarly to the lower side of the root tip. Gravicurvature of roots previously submerged in aerated water is more rapid when roots are oriented vertically for 1-2 h in humid air prior to being oriented horizontally. The more rapid gravicurvature of these roots correlates positively with the accumulation of mucilage at the tips of roots during the time the roots are oriented vertically. Therefore, the onset of gravicurvature and the ability of roots to transport Ca to the lower sides of their tips correlate positively with the presence of mucilage at their tips. These results suggest that mucilage may be important for the transport of Ca across root caps.

3. ONTARIO MINE. ADIT ENTRANCE WITH TIN ROOF. TIP TOP ...

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

3. ONTARIO MINE. ADIT ENTRANCE WITH TIN ROOF. TIP TOP IS LOCATED IN LINE WITH 'Y' BRANCH AND THE TAILING PILE FOR TIP TOP IS VISIBLE JUST TO RIGHT OF IT. CAMERA POINTED SOUTH-SOUTHEAST. - Florida Mountain Mining Sites, Ontario Mine, Northwest side of Florida Mountain, Silver City, Owyhee County, ID

Tip-enhanced near-field Raman spectroscopy with a scanning tunneling microscope and side-illumination optics.

PubMed

Yi, K J; He, X N; Zhou, Y S; Xiong, W; Lu, Y F

2008-07-01

Conventional Raman spectroscopy (RS) suffers from low spatial resolution and low detection sensitivity due to the optical diffraction limit and small interaction cross sections. It has been reported that a highly localized and significantly enhanced electromagnetic field could be generated in the proximity of a metallic tip illuminated by a laser beam. In this study, a tip-enhanced RS system was developed to both improve the resolution and enhance the detection sensitivity using the tip-enhanced near-field effects. This instrument, by combining RS with a scanning tunneling microscope and side-illumination optics, demonstrated significant enhancement on both optical sensitivity and spatial resolution using either silver (Ag)-coated tungsten (W) tips or gold (Au) tips. The sensitivity improvement was verified by observing the enhancement effects on silicon (Si) substrates. Lateral resolution was verified to be below 100 nm by mapping Ag nanostructures. By deploying the depolarization technique, an apparent enhancement of 175% on Si substrates was achieved. Furthermore, the developed instrument features fast and reliable optical alignment, versatile sample adaptability, and effective suppression of far-field signals.

Positive and negative tropic curvature induced by microbeam irradiation of protonemal tip cells of the moss Ceratodon purpureus.

PubMed

Lamparter, T; Kagawa, T; Brücker, G; Wada, M

2004-01-01

The photoreceptor phytochrome mediates tropic responses in protonemata of the moss Ceratodon purpureus. Under standard conditions the tip cells grow towards unilateral red light, or perpendicular to the electrical vector of polarized light. In this study the response of tip cells to partial irradiation of the apical region was analysed using a microbeam apparatus. The fluence response curve gave an unexpected pattern: whereas a 15-min microbeam with light intensities around 3 micro mol m (-2) s (-1) induced a growth curvature towards the irradiated side, higher light intensities around 100 micro mol m (-2) s (-1) caused a negative response, the cells grew away from the irradiated side. This avoidance response is explained by two effects: the light intensity is high enough to induce photoconversion into the active Pfr form of phytochrome, not only on the irradiated but also on the non-irradiated side by stray light. At the same time, the strong light on the irradiated side acts antagonistically to Pfr. As a result of this inhibition, the growth direction is moved to the light-avoiding side. Such a Pfr-independent mechanism might be important for the phototropic response to distinguish between the light-directed and light-avoiding side under unilateral light.

Neurovascular risks of sacral screws with bicortical purchase: an anatomical study.

PubMed

Ergur, Ipek; Akcali, Omer; Kiray, Amac; Kosay, Can; Tayefi, Hamid

2007-09-01

The aim of this cadaver study is to define the anatomic structures on anterior sacrum, which are under the risk of injury during bicortical screw application to the S1 and S2 pedicles. Thirty formaldehyde-preserved human male cadavers were studied. Posterior midline incision was performed, and soft tissues and muscles were dissected from the posterior part of the lumbosacral region. A 6 mm pedicle screw was inserted between the superior facet of S1 and the S1 foramen. The entry point of the S2 pedicle screw was located between S1 and S2 foramina. S1 and S2 screws were placed on both right and the left sides of all cadavers. Then, all cadavers were turned into supine position. All abdominal and pelvic organs were moved away and carefully observed for any injury. The tips of the sacral screws were marked and the relations with the anatomic structures were defined. The position of the sacral screws relative to the middle and lateral sacral arteries and veins, and the sacral sympathetic trunk were measured. There was no injury to the visceral organs. In four cases, S1 screw tip was in direct contact with middle sacral artery. In two cases, S1 screw tip was in direct contact with middle sacral vein. It was observed that the S1 screw tips were in close proximity to sacral sympathetic trunk on both right and the left sides. The tip of the S2 screw was in contact with middle sacral artery on the left side only in one case. It is found that the tip of the S2 screw was closely located with the middle sacral vein in two cases. The tip of the S2 pedicle screw was in contact with the sacral sympathetic trunk in eight cases on the right side and seven cases on the left side. Lateral sacral vein was also observed to be disturbed by the S1 and S2 screws. As a conclusion, anterior cortical penetration during sacral screw insertion carries a risk of neurovascular injury. The risk of sacral sympathetic trunk and minor vascular structures together with the major neurovascular structures and viscera should be kept in mind.

Investigation of Unsteady Tip Clearance Flow in a Low-Speed One and Half Stage Axial Compressor with LES And PIV

NASA Technical Reports Server (NTRS)

Hah, Chunill; Hathaway, Michael; Katz, Joseph; Tan, David

2015-01-01

The primary focus of this paper is to investigate how a rotor's unsteady tip clearance flow structure changes in a low speed one and half stage axial compressor when the rotor tip gap size is increased from 0.5 mm (0.49% of rotor tip blade chord, 2% of blade span) to 2.4 mm (2.34% chord, 4% span) at the design condition are investigated. The changes in unsteady tip clearance flow with the 0.62 % tip gap as the flow rate is reduced to near stall condition are also investigated. A Large Eddy Simulation (LES) is applied to calculate the unsteady flow field at these three flow conditions. Detailed Stereoscopic PIV (SPIV) measurements of the current flow fields were also performed at the Johns Hopkins University in a refractive index-matched test facility which renders the compressor blades and casing optically transparent. With this setup, the unsteady velocity field in the entire flow domain, including the flow inside the tip gap, can be measured. Unsteady tip clearance flow fields from LES are compared with the PIV measurements and both LES and PIV results are used to study changes in tip clearance flow structures. The current study shows that the tip clearance vortex is not a single structure as traditionally perceived. The tip clearance vortex is formed by multiple interlaced vorticities. Therefore, the tip clearance vortex is inherently unsteady. The multiple interlaced vortices never roll up to form a single structure. When phased-averaged, the tip clearance vortex appears as a single structure. When flow rate is reduced with the same tip gap, the tip clearance vortex rolls further upstream and the tip clearance vortex moves further radially inward and away from the suction side of the blade. When the tip gap size is increased at the design flow condition, the overall tip clearance vortex becomes stronger and it stays closer to the blade suction side and the vortex core extends all the way to the exit of the blade passage. Measured and calculated unsteady flow fields inside the tip gap agree fairly well. Instantaneous velocity vectors inside the tip gap from both the PIV and LES do show flow separation and reattachment at the entrance of tip gap as some earlier studies suggested. This area at the entrance of tip gap flow (the pressure side of the blade) is confined very close to the rotor tip section. With a small tip gap (0.5mm), the gap flow looks like a simple two-dimensional channel flow with larger velocity near the casing for both flow rates. A small area with a sharp velocity gradient is observed just above the rotor tip. This strong shear layer is turned radially inward when it collides with the incoming flow and forms the core structure of the tip clearance vortex. When tip gap size is increased to 2.4 mm at the design operation, the radial profile of the tip gap flow changes drastically. With the large tip gap, the gap flow looks like a two-dimensional channel flow only near the casing. Near the rotor top section, a bigger region with very large shear and reversed flow is observed.

A Study of the Flow Structure of Tip Vortices on a Hydrofoil

DTIC Science & Technology

1986-11-28

as measured from the flow visualization imager. . . 0 . . . 61 III.10 The vertical location of the tip vortex center as measured from the flow...pressure gra- dients of opposite sign exist on both sides of an airfoil . These gradients induce an inward lateral flow on the suc- tion side and an...And most recently, Cebeci et al. (1986) developed a viscous/inviscid interaction method to calculate the flow around airfoils , emphasizing the

A gradient of endogenous calcium forms in mucilage of graviresponding roots of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.

1988-01-01

Agar blocks that contacted the upper sides of tips of horizontally-oriented roots of Zea mays contain significantly less calcium (Ca) than blocks that contacted the lower sides of such roots. This gravity-induced gradient of Ca forms prior to the onset of gravicurvature, and does not form across tips of vertically-oriented roots or roots of agravitropic mutants. These results indicate that (1) Ca can be collected from mucilage of graviresponding roots, (2) gravity induces a downward movement of endogenous Ca in mucilage overlying the root tip, (3) this gravity-induced gradient of Ca does not form across tips of agravitropic roots, and (4) formation of a Ca gradient is not a consequence of gravicurvature. These results are consistent with gravity-induced movement of Ca being a trigger for subsequent redistribution of growth effectors (e.g. auxin) that induce differential growth and gravicurvature.

Tongue Motion Patterns in Post-Glossectomy and Typical Speakers: A Principal Components Analysis

PubMed Central

Stone, Maureen; Langguth, Julie M.; Woo, Jonghye; Chen, Hegang; Prince, Jerry L.

2015-01-01

Purpose In this study, the authors examined changes in tongue motion caused by glossectomy surgery. A speech task that involved subtle changes in tongue-tip positioning (the motion from /i/ to /s/) was measured. The hypothesis was that patients would have limited motion on the tumor (resected) side and would compensate with greater motion on the nontumor side in order to elevate the tongue tip and blade for /s/. Method Velocity fields were extracted from tagged magnetic resonance images in the left, middle, and right tongue of 3 patients and 10 controls. Principal components (PCs) analysis quantified motion differences and distinguished between the subject groups. Results PCs 1 and 2 represented variance in (a) size and independence of the tongue tip, and (b) direction of motion of the tip, body, or both. Patients and controls were correctly separated by a small number of PCs. Conclusions Motion of the tumor slice was different between patients and controls, but the nontumor side of the patients’ tongues did not show excessive or adaptive motion. Both groups contained apical and laminal /s/ users, and 1 patient created apical /s/ in a highly unusual manner. PMID:24023377

Relationship between grip, pinch strengths and anthropometric variables, types of pitch throwing among Japanese high school baseball pitchers.

PubMed

Tajika, Tsuyoshi; Kobayashi, Tsutomu; Yamamoto, Atsushi; Shitara, Hitoshi; Ichinose, Tsuyoshi; Shimoyama, Daisuke; Okura, Chisa; Kanazawa, Saeko; Nagai, Ayako; Takagishi, Kenji

2015-03-01

Grip and pinch strength are crucially important attributes and standard parameters related to the functional integrity of the hand. It seems significant to investigate normative data for grip and pinch strength of baseball players to evaluate their performance and condition. Nevertheless, few reports have explained the association between grip and pinch strength and anthropometric variables and types of pitch throwing for baseball pitchers. The aim of this study was to measure and evaluate clinical normative data for grip and tip, key, palmar pinch strength and to assess the relationship between these data and anthropometric variables and types of pitch throwing among Japanese high-school baseball pitchers. One hundred-thirty three healthy high school baseball pitchers were examined and had completed a self-administered questionnaire including items related to age, hand dominance, throwing ratio of type of pitch. A digital dynamometer was used to measure grip strength and a pinch gauge to measure tip, key and palmer pinch in both dominant and nondominant side. Body composition was measured by the multi frequency segmental body composition analyzer. Grip strength and tip and palmer pinch strength in dominant side were statistically greater than them in nondominant side (P < 0.05). There were significant associations between grip strength and height (r = 0.33, P < 0.001), body mass (r = 0.50, P < 0.001), BMI (r = 0.37, P < 0.001), muscle mass of upper extremity (r = 0.56, P < 0.001), fat free mass (r = 0.57, P < 0.001), fat mass (r = 0.22, P < 0.05) in dominant side. A stepwise multiple regression analysis revealed that fat free mass and tip, palmer, key pinch strength were predictors of grip strength in dominant side. No statistical significant correlations were found between the throwing ratio of types of pitches thrown and grip strength and tip, key, palmar pinch strength. Our result provides normative values and evidences for grip and pinch strengths in high school baseball pitchers.

Maxillary sinus volume in patients with impacted canines.

PubMed

Oz, Aslihan Zeynep; Oz, Abdullah Alper; El, Hakan; Palomo, Juan Martin

2017-01-01

To evaluate the maxillary sinus volumes in unilaterally impacted canine patients and to compare the volumetric changes that occur after the eruption of canines to the dental arch using cone beam computed tomography (CBCT). Pre- (T0) and posttreatment (T1) CBCT records of 30 patients were used to calculate maxillary sinus volumes between the impacted and erupted canine sides. The InVivoDental 5.0 program was used to measure the volume of the maxillary sinuses. The distance from impacted canine cusp tip to the target point on the palatal plane was also measured. Right maxillary sinus volume was statistically significantly smaller compared to that of the left maxillary sinus when the canine was impacted on the right side at T0. According to the T1 measurements there was no significant difference between the mean volumes of the impaction side and the contralateral side. The distance from the canine tip to its target point on the palatal plane were 17.17 mm, and the distance from the tip to the target point was 15.14 mm for the left- and right-side impacted canines, respectively, and there was a significant difference between the mean amount of change of both sides of maxillary sinuses after treatment of impacted canines. Orthodontic treatment of impacted canines created a significant increase in maxillary sinus volume when the impacted canines were closer with respect to the maxillary sinus.

Periodontal Responses to Augmented Corticotomy with Collagen Membrane Application during Orthodontic Buccal Tipping in Dogs

PubMed Central

Herr, Yeek; Kwon, Young-Hyuk; Kim, Seong-Hun; Kim, Eun-Cheol

2014-01-01

This prospective randomized split-mouth study was performed to examine the effects of absorbable collagen membrane (ACM) application in augmented corticotomy using deproteinized bovine bone mineral (DBBM), during orthodontic buccal tipping movement in the dog. After buccal circumscribing corticotomy and DBBM grafting into the decorticated area, flaps were repositioned and sutured on control sides. ACM was overlaid and secured with membrane tacks, on test sides only, and the flaps were repositioned and sutured. Closed coil springs were used to apply 200 g orthodontic force in the buccolingual direction on the second and third premolars, immediately after primary flap closure. The buccal tipping angles were 31.19 ± 14.60° and 28.12 ± 11.48° on the control and test sides, respectively. A mean of 79.5 ± 16.0% of the buccal bone wall was replaced by new bone on the control side, and on the test side 78.9 ± 19.5% was replaced. ACM application promoted an even bone surface. In conclusion, ACM application in augmented corticotomy using DBBM might stimulate periodontal tissue reestablishment, which is useful for rapid orthodontic treatment or guided bone regeneration. In particular, ACM could control the formation of mesenchymal matrix, facilitating an even bone surface. PMID:25276824

Turbine blade cooling

DOEpatents

Staub, F.W.; Willett, F.T.

1999-07-20

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number. 13 figs.

Turbine blade cooling

DOEpatents

Staub, Fred Wolf; Willett, Fred Thomas

1999-07-20

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

Turbine blade cooling

DOEpatents

Staub, Fred Wolf; Willett, Fred Thomas

2000-01-01

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

Propeller noise caused by blade tip radial forces

NASA Technical Reports Server (NTRS)

Hanson, D. B.

1986-01-01

New experimental evidence which indicates the presence of leading edge and tip edge vortex flow on Prop-Fans is examined, and performance and noise consequences are addressed. It was shown that the tip edge vortex is a significant noise source, particularly for unswept Prop-Fan blades. Preliminary calculations revealed that the addition of the tip side edge source to single rotation Prop-Fans during take off conditions improved the agreement between experiment and theory at blade passing frequency. At high-speed conditions such as the Prop-Fan cruise point, the tip loading effect tends to cancel thickness noise.

RANS computations of tip vortex cavitation

NASA Astrophysics Data System (ADS)

Decaix, Jean; Balarac, Guillaume; Dreyer, Matthieu; Farhat, Mohamed; Münch, Cécile

2015-12-01

The present study is related to the development of the tip vortex cavitation in Kaplan turbines. The investigation is carried out on a simplified test case consisting of a NACA0009 blade with a gap between the blade tip and the side wall. Computations with and without cavitation are performed using a R ANS modelling and a transport equation for the liquid volume fraction. Compared with experimental data, the R ANS computations turn out to be able to capture accurately the development of the tip vortex. The simulations have also highlighted the influence of cavitation on the tip vortex trajectory.

Load-bearing Characters Analysis of Large Diameter Rock-Socketed Filling Piles Based on Self-Balanced Method

NASA Astrophysics Data System (ADS)

tongqing, Wu; liang, Li; xinjian, Liu; Xu, nianchun; Tian, Mao

2018-03-01

Self-balanced method is carried out on the large diameter rock-socketed filling piles of high-pile wharf at Inland River, to explore the distribution laws of load-displacement curve, pile internal force, pile tip friction resistance and pile side friction resistance under load force. The results showed that: the tip resistance of S1 and S2 test piles accounted for 53.4% and 53.6% of the pile bearing capacity, respectively, while the total side friction resistance accounted for 46.6% and 46.4% of the pile bearing capacity, respectively; both the pile tip friction resistance and pile side friction resistance can be fully played, and reach to the design requirements. The reasonability of large diameter rock-socketed filling design is verified through test analysis, which can provide basis for the optimization of high-pile wharf structural type, thus reducing the wharf project cost, and also providing reference for the similar large diameter rock-socketed filling piles of high-pile wharf at Inland River.

Role of LiCoO 2 Surface Terminations in Oxygen Reduction and Evolution Kinetics

DOE PAGES

Han, Binghong; Qian, Danna; Risch, Marcel; ...

2015-03-22

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities of LiCoO 2 nanorods with sizes in the range from 9 to 40 nm were studied in alkaline solution. The sides of these nanorods were terminated with low-index surfaces such as (003) while the tips were terminated largely with high-index surfaces such as (104) as revealed by high-resolution transmission electron microscopy. Electron energy loss spectroscopy demonstrated that low-spin Co 3+ prevailed on the sides, while the tips exhibited predominantly high- or intermediate-spin Co 3+. We correlated the electronic and atomic structure to higher specific ORR and OER activities at themore » tips as compared to the sides, which was accompanied by more facile redox of Co 2+/3+ and higher charge transferred per unit area. These findings highlight the critical role of surface terminations and electronic structures of transition metal oxides on the ORR and OER activity.« less

Mechanism of Prism-Coupled Scanning Tunneling Microscope Light Emission

NASA Astrophysics Data System (ADS)

Iida, Wataru; Ahamed, Jamal U.; Katano, Satoshi; Uehara, Yoichi

2011-09-01

We have investigated the mechanism of scanning tunneling microscope light emission (STM-LE) in a prism-coupled configuration using finite difference time domain analysis. In this configuration, the sample is a metallic thin film evaporated on the bottom surface of a hemispherical glass prism. STM light emitted into the prism (prism-side emission) through the metallic film is measured. Since both localized surface plasmons (LSP) and surface plasmon polaritons (SPP) contribute to prism-side emission, this emission is stronger than that in conventional STM-LE measured from the sample surface side, which is radiated by LSP alone. We show that the spatial resolution of prism-side emission is determined not by the propagation length of SPP, but by the lateral size of LSP, similarly to conventional (i.e., tip side) STM-LE. Thus, we conclude that, by using the prism-coupled configuration, the signal level of STM-LE improves without the loss of spatial resolution attained in tip side emission.

Tip cap for a turbine rotor blade

DOEpatents

Kimmel, Keith D

2014-03-25

A turbine rotor blade with a spar and shell construction, and a tip cap that includes a row of lugs extending from a bottom side that form dovetail grooves that engage with similar shaped lugs and grooves on a tip end of the spar to secure the tip cap to the spar against radial displacement. The lug on the trailing edge end of the tip cap is aligned perpendicular to a chordwise line of the blade in the trailing edge region in order to minimize stress due to the lugs wanting to bend under high centrifugal loads. A two piece tip cap with lugs at different angles will reduce the bending stress even more.

7. Oil house, view northeast, west and south sides ...

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

7. Oil house, view northeast, west and south sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

6. Keeper's house, view southwest, east and north sides ...

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

6. Keeper's house, view southwest, east and north sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

8. Small boathouse, view northwest, south and east sides ...

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

8. Small boathouse, view northwest, south and east sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

9. Large boathouse, view northwest, south and east sides ...

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

9. Large boathouse, view northwest, south and east sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

4. Light tower, view southeast, north and west sides ...

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

4. Light tower, view southeast, north and west sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

New Technique for Fabrication of Scanning Single-Electron Transistor Microscopy Tips

NASA Astrophysics Data System (ADS)

Goodwin, Eric; Tessmer, Stuart

Fabrication of glass tips for Scanning Single-Electron Transistor Microscopy (SSETM) can be expensive, time consuming, and inconsistent. Various techniques have been tried, with varying levels of success in regards to cost and reproducibility. The main requirement for SSETM tips is to have a sharp tip ending in a micron-scale flat face to allow for deposition of a quantum dot. Drawing inspiration from methods used to create tips from optical fibers for Near-Field Scanning Optical Microscopes, our group has come up with a quick and cost effective process for creating SSETM tips. By utilizing hydrofluoric acid to etch the tips and oleic acid to guide the etch profile, optical fiber tips with appropriate shaping can be rapidly prepared. Once etched, electric leads are thermally evaporated onto each side of the tip, while an aluminum quantum dot is evaporated onto the face. Preliminary results using various metals, oxide layers, and lead thicknesses have proven promising.

Side Effects: Hair Loss (Alopecia)

Cancer.gov

Hair loss, also called alopecia, is a side effect of cancer treatments, such as chemotherapy and radiation therapy. Learn how to cope with and manage hair loss. Listen to tips from others who have experienced hair loss.

Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

PubMed

Payne, Marielle; Georgescu, Dan; Waite, Aaron N; Olson, Randall J

2006-08-01

To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. University ophthalmology department. The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

Retrieval of a detached transseptal sheath tip from a right pulmonary artery branch following catheter ablation.

PubMed

Schricker, Amir A; Feld, Gregory K; Tsimikas, Sotirios

2015-11-15

Transseptal introducer sheaths are being used with increasing frequency for left-sided arrhythmia ablations and structural heart disease interventions. Sheath tip detachment and embolization is an uncommon but known complication, and several sheaths have been recalled due to such complications. We report a unique case of a fractured transseptal sheath tip that embolized to a branch of the right pulmonary artery in a patient who had undergone ablation of a left-sided atypical atrial flutter. During final removal of one of the two long 8.5-French SL1 transseptal sheaths used routinely as part of the ablation, the radiopaque tip of the sheath fractured and first embolized to the right atrium and subsequently to a secondary right pulmonary artery branch. Using techniques derived from percutaneous interventional approaches, including a multipurpose catheter, coronary guidewire, and monorail angioplasty balloon, the sheath tip was successfully wired through its inner lumen, trapped from the inside with the balloon, and removed from the body via a large femoral vein sheath, without complications. The approach detailed in this case may guide future cases and circumvent urgent surgical intervention. © 2015 Wiley Periodicals, Inc.

Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). III. A model to explain the differential georesponsiveness of primary and lateral roots

NASA Technical Reports Server (NTRS)

Ransom, J. S.; Moore, R.

1985-01-01

Half-tipped primary and lateral roots of Phaseolus vulgaris bend toward the side of the root on which the intact half tip remains. Therefore, tips of lateral and primary roots produce growth effectors capable of inducing gravicurvature. The asymmetrical placement of a tip of a lateral root onto a detipped primary root results in the root bending toward the side of the root onto which the tip was placed. That is, the lesser graviresponsiveness of lateral roots as compared with primary roots is not due to the inability of their caps to produce growth inhibitors. The more pronounced graviresponsiveness of primary roots is positively correlated with the presence of columella tissues that are 3.8 times longer, 1.7 times wider, and 10.5 times more voluminous than the columellas of lateral roots. We propose that the lack of graviresponsiveness exhibited by lateral roots is due to the fact that they (i) produce smaller amounts of the inhibitor than primary (i.e., strongly graviresponsive) roots and (ii) are unable to redistribute the inhibitor so as to be able to create a concentration gradient sufficient to induce a pronounced gravitropic response.

Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Gupta, Abhinav; Shyam, Vikram

2014-01-01

This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the Energy Efficient Engine (EEE) High Pressure Turbine (HPT) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by (1) injection from the tip near the pressure side, (2) injection from the tip surface at the camber line, and (3) injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000, and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg, -30 deg, and 90 deg to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 deg toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage.

Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Gupta, Abhinav; Shyam, Vikram

2014-01-01

This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the EEE (Energy Efficient Engine) HPT (High Pressure Turbine) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by 1. injection from the tip near the pressure side, 2. injection from the tip surface at the camber line, and 3. injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000 and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg., -30 deg. and 90 deg. to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 degrees toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage.

Thulium fiber laser-induced vapor bubble dynamics using bare, tapered, ball, hollow steel, and muzzle brake fiber optic tips

NASA Astrophysics Data System (ADS)

Gonzalez, David A.; Hardy, Luke A.; Hutchens, Thomas C.; Irby, Pierce B.; Fried, Nathaniel M.

2018-03-01

This study characterizes laser-induced vapor bubble dynamics for five different distal fiber optic tip configurations, to provide insight into stone retropulsion commonly experienced during laser ablation of kidney stones. A thulium fiber laser with 1908-nm wavelength delivered 34-mJ energy per pulse at 500-μs pulse duration through five different fibers such as 100-μm-core / 170-μm-OD bare fiber tip, 150- to 300-μm-core tapered fiber tip, 100-μm-core / 300-μm-OD ball tip fiber, 100-μm-core / 340-μm-OD hollow steel tip fiber, and 100-μm-core / 560-μm-OD muzzle brake fiber tip. A high-speed camera with 10-μm-spatial and 9.5-μs-temporal resolution was used to image the vapor bubble dynamics. A needle hydrophone measured pressure transients in the forward (0 deg) and side (90 deg) directions while placed at a 6.8 ± 0.4 mm distance from the distal fiber tip. Maximum bubble dimensions (width/length) averaged 0.7/1.5, 1.0/1.6, 0.5/1.1, 0.8/1.9, and 0.7 / 1.5 mm, for bare, tapered, ball, hollow steel, and muzzle brake fiber tips, respectively (n = 5). The hollow steel tip exhibited the most elongated vapor bubble shape, translating into increased forward pressure in this study and consistent with higher stone retropulsion in previous reports. Relative pressures (a.u.) in (forward/side) directions averaged 1.7/1.6, 2.0/2.0, 1.4/1.2, 6.8/1.1, and 0.3/1.2, for each fiber tip (n = 5). For the hollow steel tip, forward pressure was 4 × higher than for the bare fiber. For the muzzle brake fiber tip, forward pressure was 5 × lower than the bare fiber. Bubble dimensions and pressure measurements demonstrated that the muzzle brake fiber tip reduced forward pressure by partially venting vapors through the portholes, which is consistent with the observation of lower stone retropulsion in previous reports.

EAST FRONT AND NORTH SIDE OF ADMINISTRATION BUILDING. VIEW TO ...

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

EAST FRONT AND NORTH SIDE OF ADMINISTRATION BUILDING. VIEW TO SOUTH - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

EAST FRONT AND SOUTH SIDE OF ADMINISTRATION BUILDING. VIEW TO ...

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

EAST FRONT AND SOUTH SIDE OF ADMINISTRATION BUILDING. VIEW TO NORTH. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

SOUTHWEST SIDE AND SOUTHEAST FRONT OF RODMAN MONUMENT. VIEW TO ...

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

SOUTHWEST SIDE AND SOUTHEAST FRONT OF RODMAN MONUMENT. VIEW TO NORTHEAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

NORTHWEST BACK AND SOUTHWEST SIDE OF RODMAN MONUMENT. VIEW TO ...

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

NORTHWEST BACK AND SOUTHWEST SIDE OF RODMAN MONUMENT. VIEW TO EAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

Theoretical investigation for excitation light and fluorescence signal of fiber optical sensor using tapered fiber tip.

PubMed

Yuan, Yinquan; Ding, Liyun

2011-10-24

For fiber optical sensor made of tapered fiber tip, the effects of the geometrical parameters of tapered tip on two important factors have been investigated. One factor is the intensity of the evanescent wave into fluorescent layer through core-medium interface; the other is the intensity of fluorescence signal transmitted from fluorescent layer to measurement end. A dependence relation of the intensity of fluorescence signal transmitted from fluorescent layer to measurement end upon the geometrical parameters of tapered tip has been obtained. Theoretical results show that the intensity of the evanescent wave into fluorescent layer rises with the decrease of the end diameter of tapered tip, and the increase of the tip length; and the transmitted power of fluorescence signal increases linearly with the increase of the tip length due to the contribution of the side area of tapered tip. © 2011 Optical Society of America

Single-Molecule Tribology: Force Microscopy Manipulation of a Porphyrin Derivative on a Copper Surface.

PubMed

Pawlak, Rémy; Ouyang, Wengen; Filippov, Alexander E; Kalikhman-Razvozov, Lena; Kawai, Shigeki; Glatzel, Thilo; Gnecco, Enrico; Baratoff, Alexis; Zheng, Quanshui; Hod, Oded; Urbakh, Michael; Meyer, Ernst

2016-01-26

The low-temperature mechanical response of a single porphyrin molecule attached to the apex of an atomic force microscope (AFM) tip during vertical and lateral manipulations is studied. We find that approach-retraction cycles as well as surface scanning with the terminated tip result in atomic-scale friction patterns induced by the internal reorientations of the molecule. With a joint experimental and computational effort, we identify the dicyanophenyl side groups of the molecule interacting with the surface as the dominant factor determining the observed frictional behavior. To this end, we developed a generalized Prandtl-Tomlinson model parametrized using density functional theory calculations that includes the internal degrees of freedom of the side group with respect to the core and its interactions with the underlying surface. We demonstrate that the friction pattern results from the variations of the bond length and bond angles between the dicyanophenyl side group and the porphyrin backbone as well as those of the CN group facing the surface during the lateral and vertical motion of the AFM tip.

Static biofilm removal around ultrasonic tips in vitro.

PubMed

Thurnheer, Thomas; Rohrer, Elodie; Belibasakis, Georgios N; Attin, Thomas; Schmidlin, Patrick R

2014-09-01

This study aims to investigate the biofilm removal capacity of two ultrasonic tips under standardized conditions using a multi-species biofilm model. Six-species biofilms were grown on hydroxyapatite discs for 64.5 h and were treated for 15 s with a standardized load of 40 g with a piezoelectric or magnetostrictive device. Tips were applied either with the tip end or with the side facing downwards. Detached bacteria were determined in the supernatant and colony-forming units (CFUs) counted after 72 h of incubation. Untreated specimens served as controls. Moreover, the biofilms remaining on the hydroxyapatite surface after treatment were stained using the Live/Dead stain, and the pattern of their detachment was assessed by confocal laser scanning microscopy (CLSM). As compared to the untreated control, it was found that only a side application of the magnetostrictive device was able to remove efficiently the biofilm. In contrast, its tip application as well as both applications of the piezoelectric device removed significantly less bacteria from the biofilm structure. These findings were corroborated by CLSM observation. Both ultrasonic tips under investigations led to bacterial detachment, but the action mode as well as the tip configuration and adaptation appeared to be influenced by the biofilm removal effectiveness. Biofilm removal remains a main goal of ultrasonic debridement. This should be reflected in respective laboratory investigations. The presented combination of methods applied on a multi-species biofilm model in vitro allows the evaluation of the effectiveness of different ultrasonic scaler applications.

Low HAP/VOC Compliant Resins for Military Applications

DTIC Science & Technology

2011-09-01

of such resins are poor. Various solutions have been proposed over the years, but most suffer from a number of drawbacks that have prevented their...tip-over involved tipping the container onto its sides. The impact test involved swinging the container as a pendulum into a rigid wall. The

Drill Bit Tip on Mars Rover Curiosity, Side View

NASA Image and Video Library

2013-02-04

The shape of the tip of the bit in the drill of NASA Mars rover Curiosity is apparent in this view recorded by the remote micro-imager in the rover ChemCam instrument on Mars. Jan. 29, 2012; the bit is about 0.6 inch 1.6 centimeters wide.

Rotor blade assembly having internal loading features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soloway, Daniel David

Rotor blade assemblies and wind turbines are provided. A rotor blade assembly includes a rotor blade having exterior surfaces defining a pressure side, a suction side, a leading edge and a trailing edge each extending between a tip and a root, the rotor blade defining a span and a chord, the exterior surfaces defining an interior of the rotor blade. The rotor blade assembly further includes a loading assembly, the loading assembly including a weight disposed within the interior and movable generally along the span of the rotor blade, the weight connected to a rotor blade component such that movementmore » of the weight towards the tip causes application of a force to the rotor blade component by the weight. Centrifugal force due to rotation of the rotor blade biases the weight towards the tip.« less

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

NASA Technical Reports Server (NTRS)

Lee, J. S.; Mulkey, T. J.; Evans, M. L.

1984-01-01

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

Monopolar radiofrequency facial tightening: a retrospective analysis of efficacy and safety in over 600 treatments.

PubMed

Weiss, Robert A; Weiss, Margaret A; Munavalli, Girish; Beasley, Karen L

2006-09-01

Monopolar radiofrequency skin heating coupled with cryogen cooling of facial skin for skin tightening has been utilized on over 10,000 patients since 2002. In order to establish the actual rate and degree of side effects in our clinical experience, a retrospective chart review was performed. Charts and clinical images of over 600 consecutive patient treatments between May 2002 and June 2006 using a monopolar radiofrequency device (Thermacool, Thermage, Haywood, CA) for skin tightening at the Maryland Laser, Skin and Vein Institute were retrospectively reviewed. The primary presentation for treatment was skin laxity of the lower face. Treatment was delivered with a 1-cm2 standard tip at fluences of 81 to 124 J/cm2 (level of 12.5 to 15), a 1-cm2 "fast" tip at fluences of 62 to 109 J/cm2 (level of 72.0 to 76.0), a 1.5-cm2 "big fast" tip at fluences of 75 to 130 J/cm2 (level of 61.5 to 65), and a 3-cm2 "bigger" tip at equivalent fluences as each became available. As treatment algorithms evolved over 4 years, the algorithm of multiple passes at lower fluence associated with better clinical outcomes and greater patient acceptance has been adopted. The most common immediate and expected clinical effects were erythema and edema lasting less than 24 hours, although 6 patients reported edema lasting for up to 1 week. There were no permanent side effects. In total, 2.7% of treatments resulted in temporary side effects, the most significant of which was a slight depression on the cheek (n = 1), which completely resolved within 3.5 months. Other side effects included localized areas of acneiform subcutaneous erythematous papules (n = 4) and a linear superficial crust (n = 1) with the original tip, all of which resolved within 1 week. One patient reported small erythematous subcutaneous nodules resolving in 17 days. Tenderness of the neck lasting from 2 weeks (n = 2) to 3 weeks (n = 1) was also reported. Our data, obtained in an office setting without injectable anesthetic or i.v. sedation, indicate that monopolar RF for skin tightening is a very safe procedure. The treatment algorithm and tips have evolved over several years leading to increased safety and efficacy. Side effects are infrequent, self-limited, and minor, comparing favorably to other nonablative devices utilized for facial rejuvenation.

AGOR 28

DTIC Science & Technology

2016-05-18

Aft Deck Noise Levels – RFW in the works. • Steering Hydraulics – Reports from Armstrong indicate that the system hydraulics over heat during DP...7 • Propeller Tips - The local Hundested vendor and a...MRU Upper Transducer Room 13 Hundested began work “shaping” the outer edge of the propeller tips. Stbd side completed in approx. 3

Influence of electrical fields and asymmetric application of mucilage on curvature of primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Marcum, H.; Moore, R.

1990-01-01

Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl2, but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that 1) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast.

Root gravitropism

NASA Technical Reports Server (NTRS)

Masson, P. H.

1995-01-01

When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Andrew; Butte, Manish J., E-mail: manish.butte@stanford.edu

2014-08-04

We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, andmore » results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.« less

On the Connection Between Flap Side-Edge Noise and Tip Vortex Dynamics

NASA Technical Reports Server (NTRS)

Casalino, D.; Hazir, A.; Fares, E.; Duda, B.; Khorrami, M. R.

2015-01-01

The goal of the present work is to investigate how the dynamics of the vortical flow about the flap side edge of an aircraft determine the acoustic radiation. A validated lattice- Boltzmann CFD solution of the unsteady flow about a detailed business jet configuration in approach conditions is used for the present analysis. Evidence of the connection between the noise generated by several segments of the inboard flap tip and the aerodynamic forces acting on the same segments is given, proving that the noise generation mechanism has a spatially coherent and acoustically compact character on the scale of the flap chord, and that the edge-scattering effects are of secondary importance. Subsequently, evidence of the connection between the kinematics of the tip vortex system and the aerodynamic force is provided. The kinematics of the dual vortex system are investigated via a core detection technique. Emphasis is placed on the mutual induction effects between the two main vortices rolling up from the pressure and suction sides of the flap edge. A simple heuristic formula that relates the far-field noise spectrum and the cross-spectrum of the unsteady vortical positions is developed.

2. Fog signal house and light tower, view west southwest, ...

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

2. Fog signal house and light tower, view west southwest, southeast and northeast sides of signal house, east and north sides of tower - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

1. Light tower and fog signal house, view south southeast, ...

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

1. Light tower and fog signal house, view south southeast, east and north sides of tower, northeast and northwest sides of signal house - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

Gas turbine blade film cooling and blade tip heat transfer

NASA Astrophysics Data System (ADS)

Teng, Shuye

The detailed heat transfer coefficient and film cooling effectiveness distributions as well as the detailed coolant jet temperature profiles on the suction side of a gas turbine blade were measured using a transient liquid crystal image method and a traversing cold wire and thermocouple probe, respectively. The blade has only one row of film holes near the gill hole portion on the suction side of the blade. The hole geometries studied include standard cylindrical holes and holes with diffuser shaped exit portion (i.e. fanshaped holes and laidback fanshaped holes). Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity was 5.3 x 105. The upstream unsteady wakes were simulated using a spoke-wheel type wake generator. The wake Strouhal number was kept at 0 and 0.1. The coolant blowing ratio was varied from 0.4 to 1.2. Results show that both expanded holes have significantly improved thermal protection over the surface downstream of the ejection location, particularly at high blowing ratios. However, the expanded hole injections induce earlier boundary layer transition to turbulence and enhance heat transfer coefficients at the latter part of the blade suction surface. In general, the unsteady wake tends to reduce film cooling effectiveness. Measurements of detailed heat transfer coefficient distributions on a turbine blade tip were performed in the same wind tunnel facility as above. The central blade had a variable tip gap clearance. Measurements were made at three different tip gap clearances of about 1.1%, 2.1%, and 3% of the blade span. Static pressure distributions were measured in the blade mid-span and on the shroud surface. Detailed heat transfer coefficient distributions were measured on the blade tip surface. Results show that reduced tip clearance leads to reduced heat transfer coefficient over the blade tip surface. Results also show that reduced tip clearance tends to weaken the unsteady wake effect on blade tip heat transfer.

7. Keeper's house, fog signal house and light tower, view ...

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

7. Keeper's house, fog signal house and light tower, view north northeast, west and south sides of keeper's house and tower, southwest and southeast sides of fog signal house - West Quoddy Head Light Station, At eastern tip of West Quaddy Head, Lubec, Washington County, ME

Root-tip-mediated inhibition of hydrotropism is accompanied with the suppression of asymmetric expression of auxin-inducible genes in response to moisture gradients in cucumber roots

PubMed Central

Miyabayashi, Sachiko; Sugita, Tomoki; Kobayashi, Akie; Yamazaki, Chiaki; Miyazawa, Yutaka; Kamada, Motoshi; Kasahara, Haruo; Osada, Ikuko; Shimazu, Toru; Fusejima, Yasuo; Higashibata, Akira; Yamazaki, Takashi; Ishioka, Noriaki; Takahashi, Hideyuki

2018-01-01

In cucumber seedlings, gravitropism interferes with hydrotropism, which results in the nearly complete inhibition of hydrotropism under stationary conditions. However, hydrotropic responses are induced when the gravitropic response in the root is nullified by clinorotation. Columella cells in the root cap sense gravity, which induces the gravitropic response. In this study, we found that removing the root tip induced hydrotropism in cucumber roots under stationary conditions. The application of auxin transport inhibitors to cucumber seedlings under stationary conditions suppressed the hydrotropic response induced by the removal of the root tip. To investigate the expression of genes related to hydrotropism in de-tipped cucumber roots, we conducted transcriptome analysis of gene expression by RNA-Seq using seedlings exhibiting hydrotropic and gravitropic responses. Of the 21 and 45 genes asymmetrically expressed during hydrotropic and gravitropic responses, respectively, five genes were identical. Gene ontology (GO) analysis indicated that the category auxin-inducible genes was significantly enriched among genes that were more highly expressed in the concave side of the root than the convex side during hydrotropic or gravitropic responses. Reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR) analysis revealed that root hydrotropism induced under stationary conditions (by removing the root tip) was accompanied by the asymmetric expression of several auxin-inducible genes. However, intact roots did not exhibit the asymmetric expression patterns of auxin-inducible genes under stationary conditions, even in the presence of a moisture gradient. These results suggest that the root tip inhibits hydrotropism by suppressing the induction of asymmetric auxin distribution. Auxin transport and distribution not mediated by the root tip might play a role in hydrotropism in cucumber roots. PMID:29324818

1. Keeper's house, small boathouse, and light tower, view east, ...

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

1. Keeper's house, small boathouse, and light tower, view east, west and south sides of keeper's house, west side of boathouse and tower - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

Numerical investigation of tip clearance cavitation in Kaplan runners

NASA Astrophysics Data System (ADS)

Nikiforova, K.; Semenov, G.; Kuznetsov, I.; Spiridonov, E.

2016-11-01

There is a gap between the Kaplan runner blade and the shroud that makes for a special kind of cavitation: cavitation in the tip leakage flow. Two types of cavitation caused by the presence of clearance gap are known: tip vortex cavitation that appears at the core of the rolled up vortex on the blade suction side and tip clearance cavitation that appears precisely in the gap between the blade tip edge and the shroud. In the context of this work numerical investigation of the model Kaplan runner has been performed taking into account variable tip clearance for several cavitation regimes. The focus is put on investigation of structure and origination of mechanism of cavitation in the tip leakage flow. Calculations have been performed with the help of 3-D unsteady numerical model for two-phase medium. Modeling of turbulent flow in this work has been carried out using full equations of Navier-Stokes averaged by Reynolds with correction for streamline curvature and system rotation. For description of this medium (liquid-vapor) simplification of Euler approach is used; it is based on the model of interpenetrating continuums, within the bounds of this two- phase medium considered as a quasi-homogeneous mixture with the common velocity field and continuous distribution of density for both phases. As a result, engineering techniques for calculation of cavitation conditioned by existence of tip clearance in model turbine runner have been developed. The detailed visualization of the flow was carried out and vortex structure on the suction side of the blade was reproduced. The range of frequency with maximum value of pulsation was assigned and maximum energy frequency was defined; it is based on spectral analysis of the obtained data. Comparison between numerical computation results and experimental data has been also performed. The location of cavitation zone has a good agreement with experiment for all analyzed regimes.

Changes in extracellular calcium activity during gravity sensing in maize roots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bjoerkman, T.; Cleland, R.E.

1990-05-01

A redistribution of calcium downward across the root cap has been proposed as an essential part of gravitropism in roots. Exogenous {sup 45}Ca moves preferentially downward across gravistimulated maize root tips. However, because of the many calcium-binding sites in the apoplast, this might not result in a physiologically effect change in the apoplasmic calcium activity. To test whether there is such a change, we measured the effect of gravistimulation on the calcium activity with calcium-specific microelectrodes. Decapped maize roots (Zea mays L. cv. Golden Cross Bantam) were grown for 31 h to regenerate gravitropic sensitivity, but not root caps. Themore » calcium activity in the apoplasm surrounding the gravity-sensing cells could then be measured. The initial pCa was 2.60 {plus minus} 0.28 (approx 2.5 mM). The calcium activity on the upper side of the root tip remained constant for about five minutes after gravistimulation, then decreased by about one half. On the lower side, after a similar lag the calcium activity doubled. Control roots, which were decapped but measured before recovering gravisensitivity (19 h), showed no change in calcium activity. We have found a distinct and rapid differential in the apoplasmic calcium activity between the upper and lower sides of gravistimulated maize root tips.« less

Orientation Dependence of Columnar Dendritic Growth with Sidebranching Behaviors in Directional Solidification: Insights from Phase-Field Simulations

NASA Astrophysics Data System (ADS)

Xing, Hui; Dong, Xianglei; Wang, Jianyuan; Jin, Kexin

2018-04-01

In this study, a thin-interface phase-field model was employed to study the orientation dependence of the columnar dendritic growth with sidebranching behaviors in directional solidification. It was found that the dimensionless tip undercooling increases with the increase of misorientation angle for three pulling velocities. The primary spacing is found to be a function of misorientation angle, and the dimensionless primary spacing with respect to the misorientation angle follows the orientation correction given by Gandin and Rappaz (Acta. Metall. 42:2233-2246, 1994). For the analysis of the dendritic tip, the two-dimensional (2-D) form of the nonaxisymmetric needle crystal was used to determine the radius of the tilted columnar dendrite. Based on the definitions of open side and constrained side of the dendrite, the analysis of the width active sidebranches and the dendritic area in 2-D with respect to the distance from the dendritic tip was carried out to investigate the asymmetrical dendrite envelop and sidebranching behaviors on the two sides in directional solidification. The obtained prefactor and exponent with respect to misorientation angle are discussed, showing that the sidebranching behaviors of a tilted columnar dendritic array obey a similar power-law relationship with that of a free dendritic growth.

Viscous Fingering on an Immiscible Reactive Interface with Variation of Interfacial Tension

NASA Astrophysics Data System (ADS)

Tsuzuki, Reiko; Nagatsu, Yuichiro; Li, Qian; Chen, Ching-Yao

2017-11-01

The effects of chemical reaction, in which surfactants are produced on the interface of two immiscible fluids, on viscous fingering in a radial Hele-Shaw flow are numerically investigated. The presence of surfactants reduces interfacial tension, which is an important factor to the fingering pattern formation. In the present study, influences of reaction rate and dispersion of produced surfactants, represented respectively by dimensionless parameters of Damkohler number and Peclet number, are evaluated systematically. Secondary fingering instability, e.g., tip-splitting and side-branching, is triggered by chemical reactions. Weaker surface tension generally induces tip-splitting. For the case of high Damkohler number, because of the vortex pairs generated within each finger, surfactant tends to accumulate significantly on the side of finger, so that side-branching is preferred. Nevertheless, side-branching is suppressed in the cases associated with low Peclet number, in which strong dispersion reduces the local variation of surfactant concentration. Considering the coupled effects by Damkohler number and Peclet number, the patterns obtained by the simulations qualitatively agree with the observations in the experiments.

Unsteady Subsonic and Transonic Potential Flow over Helicopter Rotor Blades

NASA Technical Reports Server (NTRS)

Isom, M. P.

1974-01-01

Differential equations and boundary conditions for a rotor blade in forward flight, with subsonic or transonic tip Mach number, are derived. A variety of limiting flow regimes determined by different limits involving blade thickness ratio, aspect ratio, advance ratio and maximum tip Mach number is discussed. The transonic problem is discussed in some detail, and in particular the conditions that make this problem quasi-steady or essentially unsteady are determined. Asymptotic forms of equations and boundary conditions that are valid in an appropriately scaled region of the tip and an azimuthal sector on the advancing side are derived. The equations are then put in a form that is valid from the blade tip inboard through the strip theory region.

Magnetic force microscopy with frequency-modulated capacitive tip-sample distance control

NASA Astrophysics Data System (ADS)

Zhao, X.; Schwenk, J.; Mandru, A. O.; Penedo, M.; Baćani, M.; Marioni, M. A.; Hug, H. J.

2018-01-01

In a step towards routinely achieving 10 nm spatial resolution with magnetic force microscopy, we have developed a robust method for active tip-sample distance control based on frequency modulation of the cantilever oscillation. It allows us to keep a well-defined tip-sample distance of the order of 10 nm within better than +/- 0.4 nm precision throughout the measurement even in the presence of energy dissipative processes, and is adequate for single-passage non-contact operation in vacuum. The cantilever is excited mechanically in a phase-locked loop to oscillate at constant amplitude on its first flexural resonance mode. This frequency is modulated by an electrostatic force gradient generated by tip-sample bias oscillating from a few hundred Hz up to a few kHz. The sum of the side bands’ amplitudes is a proxy for the tip-sample distance and can be used for tip-sample distance control. This method can also be extended to other scanning probe microscopy techniques.

An Optical Actuation System and Curvature Sensor for a MR-compatible Active Needle

PubMed Central

Ryu, Seok Chang; Quek, Zhan Fan; Renaud, Pierre; Black, Richard J.; Daniel, Bruce L.; Cutkosky, Mark R.

2015-01-01

A side optical actuation method is presented for a slender MR-compatible active needle. The needle includes an active region with a shape memory alloy (SMA) wire actuator, where the wire generates a contraction force when optically heated by a laser delivered though optical fibers, producing needle tip bending. A prototype, with multiple side heating spots, demonstrates twice as fast an initial response compared to fiber tip heating when 0.8 W of optical power is applied. A single-ended optical sensor with a gold reflector is also presented to measure the curvature as a function of optical transmission loss. Preliminary tests with the sensor prototype demonstrate approximately linear response and a repeatable signal, independent of the bending history. PMID:26509099

Impact of tip-gap size and periodicity on turbulent transition

NASA Astrophysics Data System (ADS)

Pogorelov, Alexej; Meinke, Matthias; Schroeder, Wolfgang

2015-11-01

Large-Eddy Simulations of the flow field in an axial fan are performed at a Reynolds number of 936.000 based on the diameter and the rotational speed of the casing wall. A finite-volume flow solver based on a conservative Cartesian cut-cell method is used to solve the unsteady compressible Navier-Stokes equations. Computations are performed at a flow rate coefficient of 0.165 and a tip-gap size of s/D =0.01, for a 72 degrees fan section resolving only one out of five blades and a full fan resolving all five blades to investigate the impact of the periodic boundary condition. Furthermore, a grid convergence study is performed using four computational grids. Results of the flow field are analyzed for the computational grid with 1 billion cells. An interaction of the turbulent wake, generated by the tip-gap vortex, with the downstream blade, is observed, which leads to a cyclic transition with high pressure fluctuations on the suction side of the blade. Two dominant frequencies are identified which perfectly match with the characteristic frequencies in the experimental sound power level such that their physical origin is explained. A variation of the tip-gap size alters the transition on the suction side, i.e., no cyclic transition is observed.

Tip-enhanced Raman mapping with top-illumination AFM.

PubMed

Chan, K L Andrew; Kazarian, Sergei G

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

The Caring Teacher: Tips to Motivate Student Learning

ERIC Educational Resources Information Center

Johnson, L. Peter

2008-01-01

The most successful educators know that there are two components to teaching: the academic side and the human side. Contrary to what most people think, the human aspect of teaching is by far the most difficult to achieve. Teachers are expected to relate to and educate a wide range of personalities, levels of maturity, and emotions. It is very…

Large Eddy Simulation of Crashback in Marine Propulsors

NASA Astrophysics Data System (ADS)

Jang, Hyunchul

Crashback is an operating condition to quickly stop a propelled vehicle, where the propeller is rotated in the reverse direction to yield negative thrust. The crashback condition is dominated by the interaction of the free stream flow with the strong reverse flow. This interaction forms a highly unsteady vortex ring, which is a very prominent feature of crashback. Crashback causes highly unsteady loads and flow separation on the blade surface. The unsteady loads can cause propulsor blade damage, and also affect vehicle maneuverability. Crashback is therefore well known as one of the most challenging propeller states to analyze. This dissertation uses Large-Eddy Simulation (LES) to predict the highly unsteady flow field in crashback. A non-dissipative and robust finite volume method developed by Mahesh et al. (2004) for unstructured grids is applied to flow around marine propulsors. The LES equations are written in a rotating frame of reference. The objectives of this dissertation are: (1) to understand the flow physics of crashback in marine propulsors with and without a duct, (2) to develop a finite volume method for highly skewed meshes which usually occur in complex propulsor geometries, and (3) to develop a sliding interface method for simulations of rotor-stator propulsor on parallel platforms. LES is performed for an open propulsor in crashback and validated against experiments performed by Jessup et al. (2004). The LES results show good agreement with experiments. Effective pressures for thrust and side-force are introduced to more clearly understand the physical sources of thrust and side-force. Both thrust and side-force are seen to be mainly generated from the leading edge of the suction side of the propeller. This implies that thrust and side-force have the same source---the highly unsteady leading edge separation. Conditional averaging is performed to obtain quantitative information about the complex flow physics of high- or low-amplitude events. The events for thrust and side force show the same tendency. The conditional averages show that during high amplitude events, the vortex ring core is closer to the propeller blades, the reverse flow induced by the propeller rotation is lower, the forward flow is higher at the root of the blades, and leading and trailing edge flow separations are larger. The instantaneous flow field shows that during low amplitude events, the vortex ring is more axisymmetric and the stronger reverse flow induced by the vortex ring suppresses the forward flow so that flow separation on the blades is smaller. During high amplitude events, the vortex ring is less coherent and the weaker reverse flow cannot overcome the forward flow. The stronger forward flow makes flow separation on the blades larger. The effect of a duct on crashback is studied with LES. Thrust mostly arises from the blade surface, but most of side-force is generated from the duct surface. Both mean and RMS of pressure are much higher on inner surface of duct, especially near blade tips. This implies that side-force on the ducted propulsor is caused by the blade-duct interaction. Strong tip leakage flow is observed behind the suction side at the tip gap. The physical source of the tip leakage flow is seen to be the large pressure difference between pressure and suction sides. The conditional average for high amplitude event shows consistent results; the tip leakage flow and pressure difference are significantly higher when thrust and side-force are higher. A sliding interface method is developed to allow simulations of rotor-stator propulsor in crashback. The method allows relative rotations between different parts of the computational grid. Search algorithm for sliding elements, data structures for message passing, and accurate interpolation scheme at the sliding interface are developed for arbitrary shaped unstructured grids on parallel computing platforms. Preliminary simulations of open propulsor in crashback show reasonable performance.

A prospective, randomized evaluation of the effects of epidural needle rotation on the distribution of epidural block.

PubMed

Borghi, Battista; Agnoletti, Vanni; Ricci, Alessandro; van Oven, Hanna; Montone, Nicoletta; Casati, Andrea

2004-05-01

We evaluated the effects of turning the tip of the Tuohy needle 45 degrees toward the operative side before threading the epidural catheter (45 degrees -rotation group, n = 24) as compared to a conventional insertion technique with the tip of the Tuohy needle oriented at 90 degrees cephalad (control group, n = 24) on the distribution of 10 mL of 0.75% ropivacaine with 10 microg sufentanil in 48 patients undergoing total hip replacement. The catheter was introduced 3 to 4 cm beyond the tip of the Tuohy needle. A blinded observer recorded sensory and motor blocks on both sides, quality of analgesia, and volumes of local anesthetic used during the first 48 h of patient-controlled epidural analgesia. Readiness to surgery required 21 +/- 6 min in the control group and 17 +/- 7 min in the 45 degree-rotation group (P > 0.50). The maximum sensory level reached on the operative side was T10 (T10-7) in the control group and T9 (T10-6) in the 45 degree-rotation group (P > 0.50); whereas the maximum sensory level reached on the nonoperative side was T10 (T12-9) in the control group and L3 (L5-T12) in the 45 degree-rotation group (P = 0.0005). Complete motor blockade of the operative limb was achieved earlier in the 45 degree-rotation than in the control group, and motor block of the nonoperative side was more intense in patients in the control group. Two-segment regression of sensory level on the surgical side was similar in the two groups, but occurred earlier on the nonoperative side in the 45 degree-rotation group (94 +/- 70 min) than in the control group (178 +/- 40 min) (P = 0.0005). Postoperative analgesia was similar in the 2 groups, but the 45 degree-rotation group consumed less local anesthetic (242 +/- 35 mL) than the control group (297 +/- 60 mL) (P = 0.0005). We conclude that the rotation of the Tuohy introducer needle 45 degrees toward the operative side before threading the epidural catheter provides a preferential distribution of sensory and motor block toward the operative side, reducing the volume of local anesthetic solution required to maintain postoperative analgesia. Turning the Tuohy introducer needle 45 degrees toward the operative side before threading the epidural catheter is a simple maneuver that produces a preferential distribution of epidural anesthesia and analgesia toward the operative side, minimizing the volume of local anesthetic required to provide adequate pain relief after total hip arthroplasty.

Large eddy simulation of tip-leakage flow in an axial flow fan

NASA Astrophysics Data System (ADS)

Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol; Kwon, Oh-Kyoung

2016-11-01

An axial flow fan with a shroud generates a complicated tip-leakage flow by the interaction of the axial flow with the fan blades and shroud near the blade tips. In this study, large eddy simulation is performed for tip-leakage flow in a forward-swept axial flow fan inside an outdoor unit of an air-conditioner, operating at the design condition of the Reynolds number of 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame is adopted. The present simulation clearly reveals the generation and evolution of tip-leakage vortex near the blade tip by the leakage flow. At the inception of the leakage vortex near the leading edge of the suction-side of the blade tip, the leakage vortex is composed of unsteady multiple vortices containing high-frequency fluctuations. As the leakage vortex develops downstream along a slant line toward the following blade, large and meandering movements of the leakage vortex are observed. Thus low-frequency broad peaks of velocity and pressure occur near the pressure surface. Supported by the KISTI Supercomputing Center (KSC-2016-C3-0027).

Gecko-inspired bidirectional double-sided adhesives.

PubMed

Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

2014-05-14

A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.

Active hexagonally segmented mirror to investigate new optical phasing technologies for segmented telescopes.

PubMed

Gonté, Frédéric; Dupuy, Christophe; Luong, Bruno; Frank, Christoph; Brast, Roland; Sedghi, Baback

2009-11-10

The primary mirror of the future European Extremely Large Telescope will be equipped with 984 hexagonal segments. The alignment of the segments in piston, tip, and tilt within a few nanometers requires an optical phasing sensor. A test bench has been designed to study four different optical phasing sensor technologies. The core element of the test bench is an active segmented mirror composed of 61 flat hexagonal segments with a size of 17 mm side to side. Each of them can be controlled in piston, tip, and tilt by three piezoactuators with a precision better than 1 nm. The context of this development, the requirements, the design, and the integration of this system are explained. The first results on the final precision obtained in closed-loop control are also presented.

Investigation of Turbulent Tip Leakage Vortex in an Axial Water Jet Pump with Large Eddy Simulation

NASA Technical Reports Server (NTRS)

Hah, Chunill; Katz, Joseph

2012-01-01

Detailed steady and unsteady numerical studies were performed to investigate tip clearance flow in an axial water jet pump. The primary objective is to understand physics of unsteady tip clearance flow, unsteady tip leakage vortex, and cavitation inception in an axial water jet pump. Steady pressure field and resulting steady tip leakage vortex from a steady flow analysis do not seem to explain measured cavitation inception correctly. The measured flow field near the tip is unsteady and measured cavitation inception is highly transient. Flow visualization with cavitation bubbles shows that the leakage vortex is oscillating significantly and many intermittent vortex ropes are present between the suction side of the blade and the tip leakage core vortex. Although the flow field is highly transient, the overall flow structure is stable and a characteristic frequency seems to exist. To capture relevant flow physics as much as possible, a Reynolds-averaged Navier-Stokes (RANS) calculation and a Large Eddy Simulation (LES) were applied for the current investigation. The present study reveals that several vortices from the tip leakage vortex system cross the tip gap of the adjacent blade periodically. Sudden changes in local pressure field inside tip gap due to these vortices create vortex ropes. The instantaneous pressure filed inside the tip gap is drastically different from that of the steady flow simulation. Unsteady flow simulation which can calculate unsteady vortex motion is necessary to calculate cavitation inception accurately even at design flow condition in such a water jet pump.

Pressurized air injection in an axial hydro-turbine model for the mitigation of tip leakage cavitation

NASA Astrophysics Data System (ADS)

Rivetti, A.; Angulo, M.; Lucino, C.; Liscia, S.

2015-12-01

Tip leakage vortex cavitation in axial hydro-turbines may cause erosion, noise and vibration. Damage due to cavitation can be found at the tip of the runner blades on the low pressure side and the discharge ring. In some cases, the erosion follows an oscillatory pattern that is related to the number of guide vanes. That might suggest that a relationship exists between the flow through the guide vanes and the tip vortex cavitating core that induces this kind of erosion. On the other hand, it is known that air injection has a beneficial effect on reducing the damage by cavitation. In this paper, a methodology to identify the interaction between guide vanes and tip vortex cavitation is presented and the effect of air injection in reducing this particular kind of erosion was studied over a range of operating conditions on a Kaplan scale model. It was found that air injection, at the expense of slightly reducing the efficiency of the turbine, mitigates the erosive potential of tip leakage cavitation, attenuates the interaction between the flow through the guide vanes and the tip vortex and decreases the level of vibration of the structural components.

Numerical analysis of turbine blade tip treatments

NASA Technical Reports Server (NTRS)

Gopalaswamy, Nath S.; Whitaker, Kevin W.

1992-01-01

Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates a preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be compared with experimental data to be obtained from a linear cascade using original GGOT blades. Results have been computed for a blade with 1 percent clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4 x 10 exp 7. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors together with velocity divergence plots reveal the general flow behavior in the clearance region. Blade tip temperature calculations suggest placement of a cavity close to the upstream side of the blade tip for reduction of overall blade tip temperature. The solutions do not account for the relative motion between the endwall and the turbine blade. The solutions obtained are generally consistent with previous work done in this area,

Do mesoscale faults near the tip of an active strike-slip fault indicate regional or local stress?

NASA Astrophysics Data System (ADS)

Yamaji, Atsushi

2017-04-01

Fault-slip analysis is used in Japan after the Great Tohoku Earthquake (2011) to judge the stability of fractures in the foundations of nuclear power plants. In case a fault-slip datum from a fracture surface is explained by the present stress condition, the fracture is thought to have a risk to be activated as a fault. So, it is important to understand the relative significance of regional and local stresses. To answer the question whether mesoscale faults indicate regional or local stress, fault-slip data were collected from the walls of a trenching site of the Nojima Fault in central Japan—an active, dextral, strike-slip fault. The fault gave rise to the 1995 Kobe earthquake, which killed more than 6000 people. The trench was placed near the fault tip, which produced compressional and extensional local stress conditions on the sides of the fault near the tip. A segment of the fault, which ruptured the surface in 1995, bounded Cretaceous granite and latest Pliocene sediments in the trench. As a result, the stress inversion of the data from the mesoscale faults observed in the trench showed both the local stresses. The present WNW-ESE regional compression was found from the compressive side, but was not in the extensional side, probably because local extension surpassed the regional compression. Instead, the regional N-S compression of the Early Pleistocene was found from the extensional side. From this project, we got the lesson that fault-slip analysis reveals regional and local stresses, and that local stress sometimes masks regional one. This work was supported by a science project of "Drilling into Fault Damage Zone" (awarded to A. Lin) of the Secretariat of Nuclear Regulation Authority (Japan).

Antidepressants: Get Tips to Cope with Side Effects

MedlinePlus

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Laser-induced asymmetric faceting and growth of a nano-protrusion on a tungsten tip

NASA Astrophysics Data System (ADS)

Yanagisawa, Hirofumi; Zadin, Vahur; Kunze, Karsten; Hafner, Christian; Aabloo, Alvo; Kim, Dong Eon; Kling, Matthias F.; Djurabekova, Flyura; Osterwalder, Jürg; Wuensch, Walter

2016-12-01

Irradiation of a sharp tungsten tip by a femtosecond laser and exposed to a strong DC electric field led to reproducible surface modifications. By a combination of field emission microscopy and scanning electron microscopy, we observed asymmetric surface faceting with sub-ten nanometer high steps. The presence of faceted features mainly on the laser-exposed side implies that the surface modification was driven by a laser-induced transient temperature rise on a scale of a couple of picoseconds in the tungsten tip apex. Moreover, we identified the formation of a nano-tip a few nanometers high located at one of the corners of a faceted plateau. The results of simulations emulating the experimental conditions are consistent with the experimental observations. The presented technique would be a new method to fabricate a nano-tip especially for generating coherent electron pulses. The features may also help to explain the origin of enhanced field emission, which leads to vacuum arcs, in high electric field devices such as radio-frequency particle accelerators.

URANS simulations of the tip-leakage cavitating flow with verification and validation procedures

NASA Astrophysics Data System (ADS)

Cheng, Huai-yu; Long, Xin-ping; Liang, Yun-zhi; Long, Yun; Ji, Bin

2018-04-01

In the present paper, the Vortex Identified Zwart-Gerber-Belamri (VIZGB) cavitation model coupled with the SST-CC turbulence model is used to investigate the unsteady tip-leakage cavitating flow induced by a NACA0009 hydrofoil. A qualitative comparison between the numerical and experimental results is made. In order to quantitatively evaluate the reliability of the numerical data, the verification and validation (V&V) procedures are used in the present paper. Errors of numerical results are estimated with seven error estimators based on the Richardson extrapolation method. It is shown that though a strict validation cannot be achieved, a reasonable prediction of the gross characteristics of the tip-leakage cavitating flow can be obtained. Based on the numerical results, the influence of the cavitation on the tip-leakage vortex (TLV) is discussed, which indicates that the cavitation accelerates the fusion of the TLV and the tip-separation vortex (TSV). Moreover, the trajectory of the TLV, when the cavitation occurs, is close to the side wall.

Cellular and dendritic growth in a binary melt - A marginal stability approach

NASA Technical Reports Server (NTRS)

Laxmanan, V.

1986-01-01

A simple model for the constrained growth of an array of cells or dendrites in a binary alloy in the presence of an imposed positive temperature gradient in the liquid is proposed, with the dendritic or cell tip radius calculated using the marginal stability criterion of Langer and Muller-Krumbhaar (1977). This approach, an approach adopting the ad hoc assumption of minimum undercooling at the cell or dendrite tip, and an approach based on the stability criterion of Trivedi (1980) all predict tip radii to within 30 percent of each other, and yield a simple relationship between the tip radius and the growth conditions. Good agreement is found between predictions and data obtained in a succinonitrile-acetone system, and under the present experimental conditions, the dendritic tip stability parameter value is found to be twice that obtained previously, possibly due to a transition in morphology from a cellular structure with just a few side branches, to a more fully developed dendritic structure.

Tip-path-plane angle effects on rotor blade-vortex interaction noise levels and directivity

NASA Technical Reports Server (NTRS)

Burley, Casey L.; Martin, Ruth M.

1988-01-01

Acoustic data of a scale model BO-105 main rotor acquired in a large aeroacoustic wind tunnel are presented to investigate the parametric effects of rotor operating conditions on blade-vortex interaction (BVI) impulsive noise. Contours of a BVI noise metric are employed to quantify the effects of rotor advance ratio and tip-path-plane angle on BVI noise directivity and amplitude. Acoustic time history data are presented to illustrate the variations in impulsive characteristics. The directionality, noise levels and impulsive content of both advancing and retreating side BVI are shown to vary significantly with tip-path-plane angle and advance ratio over the range of low and moderate flight speeds considered.

Reducing Water/Hull Drag By Injecting Air Into Grooves

NASA Technical Reports Server (NTRS)

Reed, Jason C.; Bushnell, Dennis M.; Weinstein, Leonard M.

1991-01-01

Proposed technique for reduction of friction drag on hydrodynamic body involves use of grooves and combinations of surfactants to control motion of layer on surface of such body. Surface contains many rows of side-by-side, evenly spaced, longitudinal grooves. Dimensions of grooves and sharpnesses of tips in specific case depends on conditions of flow about vessel. Requires much less air than does microbubble-injection method.

Phosphorylation regulates the water channel activity of the seed-specific aquaporin alpha-TIP.

PubMed

Maurel, C; Kado, R T; Guern, J; Chrispeels, M J

1995-07-03

The vacuolar membrane protein alpha-TIP is a seed-specific protein of the Major Intrinsic Protein family. Expression of alpha-TIP in Xenopus oocytes conferred a 4- to 8-fold increase in the osmotic water permeability (Pf) of the oocyte plasma membrane, showing that alpha-TIP forms water channels and is thus a new aquaporin. alpha-TIP has three putative phosphorylation sites on the cytoplasmic side of the membrane (Ser7, Ser23 and Ser99), one of which (Ser7) has been shown to be phosphorylated. We present several lines of evidence that the activity of this aquaporin is regulated by phosphorylation. First, mutation of the putative phosphorylation sites in alpha-TIP (Ser7Ala, Ser23Ala and Ser99Ala) reduced the apparent water transport activity of alpha-TIP in oocytes, suggesting that phosphorylation of alpha-TIP occurs in the oocytes and participates in the control of water channel activity. Second, exposure of oocytes to the cAMP agonists 8-bromoadenosine 3',5'-cyclic monophosphate, forskolin and 3-isobutyl-1-methylxanthine, which stimulate endogenous protein kinase A (PKA), increased the water transport activity of alpha-TIP by 80-100% after 60 min. That the protein can be phosphorylated by PKA was demonstrated by phosphorylating alpha-TIP in isolated oocyte membranes with the bovine PKA catalytic subunit. Third, the integrity of the three sites at positions 7, 23 and 99 was necessary for the cAMP-dependent increase in the Pf of oocytes expressing alpha-TIP, as well as for in vitro phosphorylation of alpha-TIP. These findings demonstrate that the alpha-TIP water channel can be modulated via phosphorylation of Ser7, Ser23 and Ser99.(ABSTRACT TRUNCATED AT 250 WORDS)

Novel strategy of endoscopic submucosal dissection using an insulation-tipped knife for early gastric cancer: near-side approach method

PubMed Central

Mori, Genki; Nonaka, Satoru; Oda, Ichiro; Abe, Seiichiro; Suzuki, Haruhisa; Yoshinaga, Shigetaka; Nakajima, Takeshi; Saito, Yutaka

2015-01-01

Background and study aims: Endoscopic submucosal dissection (ESD) using insulation-tipped knives (IT knives) to treat gastric lesions located on the greater curvature of the gastric body remains technically challenging because of the associated bleeding, control of which can be difficult and time consuming. To eliminate these difficulties, we developed a novel strategy which we have called the “near-side approach method” and assessed its utility. Patients and methods: We reviewed patients who underwent ESD for solitary early gastric cancer located on the greater curvature of the gastric body from January 2003 to September 2014. The technical results of ESD were compared between the group treated with the novel near-side approach method and the group treated with the conventional method. Results: This study included 238 patients with 238 lesions, 118 of which were removed using the near-side approach method and 120 of which were removed using the conventional method. The median procedure time was 92 minutes for the near-side approach method and 120 minutes for the conventional method. The procedure time was significantly shorter in the near-side approach method arm. Although, the procedure time required by an experienced endoscopist was not significantly different between the two groups (100 vs. 110 minutes), the near-side approach group showed significantly shorter procedure time for a less-experienced endoscopist (90 vs. 120 minutes). Conclusions: The near-side approach method appears to require less time to complete gastric ESD than the conventional method using IT knives for technically challenging lesions located on the greater curvature of the gastric body, especially if the procedure is performed by less-experienced endoscopists. PMID:26528496

Nose Surgery

MedlinePlus

... because of gravity, causing the sides of the nose to collapse inward, obstructing air flow. Mouth breathing or noisy and restricted breathing are common. Try lifting the tip of your nose to see if you breathe better. If so, ...

Tangential RIF turbine with particle removing means

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linhardt, H.D.

1980-12-02

A radial inflow turbine is disclosed utilizing a star wheel type of blade and wherein the inlet nozzles are located along the sides or lateral of the blade tips rather than located radially beyond the blade tips. The side approach enables the turbine to include an annular chamber outside of the moving blades and where small particles are centrifuged during operation and collected. The incoming hot gases, that propel the blades, pass through approximately a 90/sup 0/ turn and continue radially inwardly. The large particles hit the turbine blades and are projected outwardly into the annular chamber for collection andmore » subsequent removal while the smaller particles may be centrifuged in the stream of gas and immediately thrown outwardly. The turbine is capable of removing particles to as small as 2-3 microns (..mu..m).« less

Methylphenidate Induced Lip and Tongue Biting.

PubMed

Gokcen, Cem; Karadag, Mehmet; Aksoy, Ihsan

2018-05-31

Attention deficit hyperactivity disorder (ADHD) is a life-long neurodevelopmental disorder and treatment depends on pharmacotherapy because of its biological origin. Stimulant drugs are the most commonly used treatment for ADHD and they have various side effects. Herein, we report a case who bit off the tip of her tongue with Osmotic Release Oral System methylphenidate (OROS MPH) 36 mg/day, bit the tip of her lower lip with immediate release (IR) MPH 10 mg/day and lateral part of her tongue with IR MPH 20 mg/day. A diagnosis of epilepsy was unlikely because of the normal neurological examination and electroencephalography findings. This case was considered as an atypical side effect of MPH such as perseverative/compulsive behaviours and movement disorders. Clinicians should be aware of that stimulant medications may cause lip and tongue biting behavior and this may effect treatment compliance tremendously.

Extruded upper first molar intrusion: Comparison between unilateral and bilateral miniscrew anchorage.

PubMed

Sugii, Mari Miura; Barreto, Bruno de Castro Ferreira; Francisco Vieira-Júnior, Waldemir; Simone, Katia Regina Izola; Bacchi, Ataís; Caldas, Ricardo Armini

2018-01-01

The aim of his study was to evaluate the stress on tooth and alveolar bone caused by orthodontic intrusion forces in a supraerupted upper molar, by using a three-dimensional Finite Element Method (FEM). A superior maxillary segment was modeled in the software SolidWorks 2010 (SolidWorks Corporation, Waltham, MA, USA) containing: cortical and cancellous bone, supraerupted first molar, periodontal tissue and orthodontic components. A finite element model has simulated intrusion forces of 4N onto a tooth, directed to different mini-screw locations. Three different intrusion mechanics vectors were simulated: anchoring on a buccal mini-implant; anchoring on a palatal mini-implant and the association of both anchorage systems. All analyses were performed considering the minimum principal stress and total deformation. Qualitative analyses exhibited stress distribution by color maps. Quantitative analysis was performed with a specific software for reading and solving numerical equations (ANSYS Workbench 14, Ansys, Canonsburg, Pennsylvania, USA). Intrusion forces applied from both sides (buccal and palatal) resulted in a more homogeneous stress distribution; no high peak of stress was detected and it has allowed a vertical resultant movement. Buccal or palatal single-sided forces resulted in concentrated stress zones with higher values and tooth tipping to respective force side. Unilateral forces promoted higher stress in root apex and higher dental tipping. The bilateral forces promoted better distribution without evidence of dental tipping. Bilateral intrusion technique suggested lower probability of root apex resorption.

Turbine blade tip gap reduction system

DOEpatents

Diakunchak, Ihor S.

2012-09-11

A turbine blade sealing system for reducing a gap between a tip of a turbine blade and a stationary shroud of a turbine engine. The sealing system includes a plurality of flexible seal strips extending from a pressure side of a turbine blade generally orthogonal to the turbine blade. During operation of the turbine engine, the flexible seal strips flex radially outward extending towards the stationary shroud of the turbine engine, thereby reducing the leakage of air past the turbine blades and increasing the efficiency of the turbine engine.

Fabrication of hydrogel-coated single conical nanochannels exhibiting controllable ion rectification characteristics.

PubMed

Wang, Linlin; Zhang, Huacheng; Yang, Zhe; Zhou, Jianjun; Wen, Liping; Li, Lin; Jiang, Lei

2015-03-07

Heterogeneous nanochannel materials that endow new functionalities different to the intrinsic properties of two original nanoporous materials have wide potential applications in nanofluidics, energy conversion, and biosensors. Herein, we report novel, interesting hydrogel-composited nanochannel devices with regulatable ion rectification characteristics. The heterogeneous nanochannel devices were constructed by selectively coating the tip side, base side, or both sides of a single conical nanochannel membrane with thin agar hydrogel layers. The tunable ion current rectification of the nanochannels in the three different coating states was systematically demonstrated by current-voltage (I-V) curves. The asymmetric ionic transport property of the conical nanochannel was further strengthened in the tip-coating state and weakened in the base-coating state, whereas the conical nanochannel showed nearly symmetric ionic transport in the dual-coating state. Repeated experiments presented insight into the good stability and reversibility of the three coating states of the hydrogel-nanochannel-integrated systems. This work, as an example, may provide a new strategy to further design and develop multifunctional gel-nanochannel heterogeneous smart porous nanomaterials.

The midline-based nasolabial transposition (MNT) flap: an original single-stage technique for nasal tip reconstruction.

PubMed

Beustes-Stefanelli, Matthieu; O'Toole, Greg; Schertenleib, Pierre

2015-04-01

Nasolabial flaps based on the lateral side of the nose for the reconstruction of lateral nasal defects in a single-stage procedure have been described. Similarly, in midline defects, nasolabial flaps can be used but a 2-stage procedure is classically required. The Midline-based Nasolabial Transposition (MNT) flap is presented as a new single-stage procedure for nasal tip reconstruction. Between 2009 and 2011, an MNT flap was used as a single-stage procedure in 3 cases of large nasal defects of the tip where the forehead flap was either contraindicated or rejected as an option by the patient. There were no complications and a satisfactory aesthetic result was achieved in all cases. The MNT flap is a new single-stage procedure for large nasal tip defects and as such represents an interesting alternative to the classical 2-stage forehead and nasolabial flaps, especially in elderly patients.

Structure of the bacteriophage T4 long tail fiber receptor-binding tip

PubMed Central

Bartual, Sergio G.; Otero, José M.; Garcia-Doval, Carmela; Llamas-Saiz, Antonio L.; Kahn, Richard; Fox, Gavin C.; van Raaij, Mark J.

2010-01-01

Bacteriophages are the most numerous organisms in the biosphere. In spite of their biological significance and the spectrum of potential applications, little high-resolution structural detail is available on their receptor-binding fibers. Here we present the crystal structure of the receptor-binding tip of the bacteriophage T4 long tail fiber, which is highly homologous to the tip of the bacteriophage lambda side tail fibers. This structure reveals an unusual elongated six-stranded antiparallel beta-strand needle domain containing seven iron ions coordinated by histidine residues arranged colinearly along the core of the biological unit. At the end of the tip, the three chains intertwine forming a broader head domain, which contains the putative receptor interaction site. The structure reveals a previously unknown beta-structured fibrous fold, provides insights into the remarkable stability of the fiber, and suggests a framework for mutations to expand or modulate receptor-binding specificity. PMID:21041684

Effect of Different Ground Scenarios on Flow Structure of a Rotor At Hover Condition

NASA Astrophysics Data System (ADS)

Kocak, Goktug; Nalbantoglu, Volkan; Yavuz, Mehmet Metin

2017-11-01

The ground effect of a scaled model rotor at hover condition was investigated experimentally in a confined environment. Different ground effect scenarios including full, partial, and inclined conditions, compared to out of ground condition, were characterized qualitatively and quantitatively using laser illuminated smoke visualization and Laser Doppler Anemometry measurements. The results indicate that the presence of the ground affects the flow regime near the blade tip by changing the spatial extent and the path of the vortex core. After the impingement of the wake to the ground, highly unsteady and turbulent wake is observed. Both the mean and the root mean square of the induced velocity increase toward the blade tip. In line with this, the spectral power of the dominant frequency in the velocity fluctuations significantly increases toward the blade tip. All these observations are witnessed in all ground effect conditions tested in the present study. Considering the inclined ground effect in particular, it is observed that the mean induced velocities of the high side (mountain) are higher compared to the velocities of the low side (valley) in contrast to the general trend observed in the present study where the ground effect reduces the induced velocity.

On the Importance of Spatial Resolution for Flap Side Edge Noise Prediction

NASA Technical Reports Server (NTRS)

Mineck, Raymond E.; Khorrami, Mehdi R.

2017-01-01

A spatial resolution study of flap tip flow and the effects on the farfield noise signature for an 18%-scale, semispan Gulfstream aircraft model are presented. The NASA FUN3D unstructured, compressible Navier-Stokes solver was used to perform the highly resolved, time-dependent, detached eddy simulations of the flow field associated with the flap for this high-fidelity aircraft model. Following our previous work on the same model, the latest computations were undertaken to determine the causes of deficiencies observed in our earlier predictions of the steady and unsteady surface pressures and off-surface flow field at the flap tip regions, in particular the outboard tip area, where the presence of a cavity at the side-edge produces very complex flow features and interactions. The present results show gradual improvement in steady loading at the outboard flap edge region with increasing spatial resolution, yielding more accurate fluctuating surface pressures, off-surface flow field, and farfield noise with improved high-frequency content when compared with wind tunnel measurements. The spatial resolution trends observed in the present study demonstrate that the deficiencies reported in our previous computations are mostly caused by inadequate spatial resolution and are not related to the turbulence model.

Medicines and Children

MedlinePlus

... child. Here are some other tips for giving medicine safely to your child: Read and follow the label directions every time. ... new symptoms or unexpected side effects in your child The medicine doesn't appear to be working when you ...

Study of tip clearance flow in a turbomachinery cascade using large eddy simulation

NASA Astrophysics Data System (ADS)

You, Donghyun

In liquid handling systems like pumps and ducted propulsors, low pressure events in the vicinity and downstream of the rotor tip gap can induce tip-leakage cavitation which leads to noise, vibration, performance loss, and erosions of blade and casing wall. In order to analyze the dynamics of the tip-clearance flow and determine the underlying mechanism for the low pressure events, a newly developed large-eddy simulation (LES) solver which combines an immersed-boundary method with a generalized curvilinear structured grid has been employed. An analysis of the LES results has been performed to understand the mean flow field, turbulence characteristics, vortex dynamics, and pressure fluctuations in the turbomachinery cascade with tip gap. In the cascade passage, the tip-leakage jet, which is generated by the pressure difference between the pressure and suction sides of the blade tip, is found to produce highly enhanced vorticity magnitude and significant levels of turbulent kinetic energy. Based on the understanding of the flow field, a guideline for reducing viscous loss in the cascade is provided. Analyses of the energy spectra and space-time correlations of the velocity fluctuations suggest that the tip-leakage vortex is subject to pitchwise wandering motion. The largest pressure drop and most intense pressure fluctuations due to the formation of the tip-leakage vortex are found at the location where the strongest portion of the tip-leakage vortex is found. Present study suggests that the tip-leakage vortex needs to be controlled in its origin to reduce cavitation in the present configuration. The effects of tip-gap size on the end-wall vortical structures and on the velocity and pressure fields have been investigated. The present analysis indicates that the mechanism for the generation of the vorticity and turbulent kinetic energy is mostly unchanged by the tip-gap size variation. However, larger tip-gap sizes are found to be more inductive to tip-leakage cavitation judged by the levels of negative mean pressure and pressure fluctuations.

Rational design and validation of a Tip60 histone acetyltransferase inhibitor

NASA Astrophysics Data System (ADS)

Gao, Chunxia; Bourke, Emer; Scobie, Martin; Famme, Melina Arcos; Koolmeister, Tobias; Helleday, Thomas; Eriksson, Leif A.; Lowndes, Noel F.; Brown, James A. L.

2014-06-01

Histone acetylation is required for many aspects of gene regulation, genome maintenance and metabolism and dysfunctional acetylation is implicated in numerous diseases, including cancer. Acetylation is regulated by histone acetyltransferases (HATs) and histone deacetylases and currently, few general HAT inhibitors have been described. We identified the HAT Tip60 as an excellent candidate for targeted drug development, as Tip60 is a key mediator of the DNA damage response and transcriptional co-activator. Our modeling of Tip60 indicated that the active binding pocket possesses opposite charges at each end, with the positive charges attributed to two specific side chains. We used structure based drug design to develop a novel Tip60 inhibitor, TH1834, to fit this specific pocket. We demonstrate that TH1834 significantly inhibits Tip60 activity in vitro and treating cells with TH1834 results in apoptosis and increased unrepaired DNA damage (following ionizing radiation treatment) in breast cancer but not control cell lines. Furthermore, TH1834 did not affect the activity of related HAT MOF, as indicated by H4K16Ac, demonstrating specificity. The modeling and validation of the small molecule inhibitor TH1834 represents a first step towards developing additional specific, targeted inhibitors of Tip60 that may lead to further improvements in the treatment of breast cancer.

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

NASA Astrophysics Data System (ADS)

Siddique, Waseem; El-Gabry, Lamyaa; Shevchuk, Igor V.; Hushmandi, Narmin B.; Fransson, Torsten H.

2012-05-01

Two-pass channels are used for internal cooling in a number of engineering systems e.g., gas turbines. Fluid travelling through the curved path, experiences pressure and centrifugal forces, that result in pressure driven secondary motion. This motion helps in moving the cold high momentum fluid from the channel core to the side walls and plays a significant role in the heat transfer in the channel bend and outlet pass. The present study investigates using Computational Fluid Dynamics (CFD), the flow structure, heat transfer enhancement and pressure drop in a smooth channel with varying aspect ratio channel at different divider-to-tip wall distances. Numerical simulations are performed in two-pass smooth channel with aspect ratio Win/H = 1:3 at inlet pass and Wout/H = 1:1 at outlet pass for a variety of divider-to-tip wall distances. The results show that with a decrease in aspect ratio of inlet pass of the channel, pressure loss decreases. The divider-to-tip wall distance (Wel) not only influences the pressure drop, but also the heat transfer enhancement at the bend and outlet pass. With an increase in the divider-to-tip wall distance, the areas of enhanced heat transfer shifts from side walls of outlet pass towards the inlet pass. To compromise between heat transfer and pressure drop in the channel, Wel/H = 0.88 is found to be optimum for the channel under study.

An improved integrally formed radio frequency quadrupole

DOEpatents

Abbott, S.R.

1987-10-05

An improved radio frequency quadrupole is provided having an elongate housing with an elongate central axis and top, bottom and two side walls symmetrically disposed about the axis, and vanes formed integrally with the walls, the vanes each having a cross-section at right angles to the central axis which tapers inwardly toward the axis to form electrode tips spaced from each other by predetermined distances. Each of the four walls, and the vanes integral therewith, is a separate structural element having a central lengthwise plane passing through the tip of the vane, the walls having flat mounting surfaces at right angles to and parallel to the control plane, respectively, which are butted together to position the walls and vane tips relative to each other. 4 figs.

Side wire feed for welding apparatus

NASA Technical Reports Server (NTRS)

Arnett, J. C.

1974-01-01

Coaxial electrode arrangement has solid central electrode, insulated outer electrode, and transverse channel for feeding wire through tip of electrode assembly. Polymeric insulation is thrust aside by pressure, which is provided by separately operated mechanism acting through central electrode.

2. Keeper's house, light tower and bell house, view east, ...

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

2. Keeper's house, light tower and bell house, view east, west and south sides - Bass Harbor Head Light Station, At southwest tip of Mount Desert Island off State Route 102, Bass Harbor, Hancock County, ME

Three-Dimensional Soft Tissue Nasal Changes After Nasoalveolar Molding and Primary Cheilorhinoplasty in Infants With Unilateral Cleft Lip and Palate.

PubMed

Mancini, Laura; Gibson, Travis L; Grayson, Barry H; Flores, Roberto L; Staffenberg, David; Shetye, Pradip R

2018-01-01

To quantify 3-dimensional (3D) nasal changes in infants with unilateral cleft lip with or without cleft palate (UCL±P) treated by nasoalveolar molding (NAM) and cheilorhinoplasty and compare to noncleft controls. Retrospective case series of infants treated with NAM and primary cheilorhinoplasty between September, 2012 and July, 2016. Infants were included if they had digital stereophotogrammetric records at initial presentation (T1), completion of NAM (T2), and following primary cheilorhinoplasty (T3). Images were oriented in 3dMD Vultus software, and 16 nasolabial points identified. Twenty consecutively treated infants with UCL±P. Nasoalveolar molding and primary cheilorhinoplasty. Anthropometric measures of nasal symmetry and morphology were compared in the treatment group between time points using paired Student t tests. Postsurgical nasal morphology was compared to noncleft controls. Nasal tip protrusion increased, and at T3 was 2.64 mm greater than noncleft controls. Nasal base width decreased on the cleft side by 4.01 mm after NAM and by 6.73 mm after cheilorhinoplasty. Columellar length of the noncleft to cleft side decreased from 2:1 to 1:1 following NAM. Significant improvements in subnasale, columella, and nasal tip deviations from midsagittal plane were observed. Treatment improved symmetry of the alar morphology angle and the nasal base-columella angle between cleft and noncleft sides. Three-dimensional analysis of UCL±P patients demonstrated significant improvements in nasal projection, columella length, nasal symmetry, and nasal width. Compared to noncleft controls, nasal form was generally corrected, with overcorrection of nasal tip projection, columella angle, and outer nasal widths.

Operation UPSHOT-KNOTHOLE. Report to the Test Director Aircraft Participation, Nevada Proving Grounds, March-June 1953

DTIC Science & Technology

1982-06-04

Alamos Scientific Laboratory. It was calibrated before each mission and was the primary instrument for de - termining breakaway time. In order to check...wing (leading edge) 30 IS Right pylon rack Right wing tip 9 Right wing tip tank 750 50 7 Right side turbina 150 150 IS Right horizontal stabilizer...hr; however, it was planned to make two penetrations at less than H + 2 hr, probably H + 1 hr 30 min and 1 hr 45 min, de - pending on cloud

3 Steps to Building a Personal Medical Record

MedlinePlus

... Record Medline Plus: Personal Health Records American Health Information Management Association: myPHR Log in or register to post comments f t k e P Blog Category: ... making emotions expert information meetings podcast side effects survivorship tips treatment More ...

Tips to Lessen Common Side Effects of HCV Therapy

MedlinePlus

... hour before your injection, take 2 regular strength acetaminophen (Tylenol® or generic), or 2 ibuprofen (Advil®, Motrin®, ... Do not take more than 2000 mg of acetaminophen in 24 hour period. • Do not take more ...

3. Light tower and fog signal house, view northeast, west ...

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

3. Light tower and fog signal house, view northeast, west and south sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

Stitch in the side: causes, workup, and solutions.

PubMed

Eichner, E Randy

2006-12-01

Side stitch is an acute, localized, sharp, transient pain that occurs during exercise, most often in runners or swimmers, but also in those participating in team sports, and less often in cyclists. The pain is vexing and performance-limiting, but fleeting and benign. Three theories compete to explain it: diaphragmatic ischemia, stress on peritoneal ligaments, and irritation of the parietal peritoneum. The differential diagnosis seems broad, but the classic side stitch is so unique in its features and setting that a reasonable working diagnosis can be made from a careful history and physical examination. Practical tips, although anecdotal, offer lasting solutions.

Influence of the Groove on Barrier Surface on Creeping Discharge Characteristics in N2 Gas under µs Pulse Voltage

NASA Astrophysics Data System (ADS)

Ueno, Hideki; Kawano, Taichi; Sakamoto, Naoki; Nakayama, Hiroshi

For a needle-plane electrode system with a barrier, which establishes the electric field across the axis of a groove, creeping discharge characteristics in N2 gas under µs pulse voltage applications have been investigated. The distance h between the barrier surface and the needle tip as well as the distance M between the groove center and the needle tip were changed. In the case of h=0.3mm, when the needle tip is located near the far-side groove edge from the plane electrode (M=0.6mm), the flashover voltage has the maximum value. At that time, a growth of a corona is suppressed near the groove edge. These unique characteristics should associate with a field relaxation.

On the Lateral Static Stability of Low-Aspect-Ratio Rectangular Wings

NASA Astrophysics Data System (ADS)

Linehan, Thomas; Mohseni, Kamran

2017-11-01

Low-aspect-ratio rectangular wings experience a reduction in lateral static stability at angles of attack distinct from that of lift stall. Stereoscopic digital particle image velocimetry is used to elucidate the flow physics behind this trend. Rectangular wings of AR = 0.75, 1, 1.5, 3 were tested at side-slip angles β = -10° and 0° with angle of attack varied in the range α =10° -40° . In side-slip, the leading-edge separation region emerges on the leeward wing where leading-edge flow reattachment is highly intermittent due to vortex shedding. The tip vortex downwash of the AR < 1.5 wings is sufficient to restrict the shedding of leading-edge vorticity, enabling sustained lift from the leading-edge separation region to high angles of attack. The windward tip vortex grows in size with increasing angle of attack, occupying an increasingly larger percentage of the windward wing. At high angles of attack pre-lift stall, the windward tip vortex lifts off the wing, resulting in separated flow underneath it. The downwash of the AR = 3 wing is insufficient to reattach the leading-edge flow at high incidence. The flow stalls on the leeward wing with stalled flow expanding upstream toward the windward wing with increasing angle of attack.

Prediction of aerodynamic noise in a ring fan based on wake characteristics

NASA Astrophysics Data System (ADS)

Sasaki, Soichi; Fukuda, Masaharu; Tsujino, Masao; Tsubota, Haruhiro

2011-06-01

A ring fan is a propeller fan that applies an axial-flow impeller with a ring-shaped shroud on the blade tip side. In this study, the entire flow field of the ring fan is simulated using computational fluid dynamics (CFD); the accuracy of the CFD is verified through a comparison with the aerodynamic characteristics of a propeller fan of current model. Moreover, the aerodynamic noise generated by the fan is predicted on the basis of the wake characteristics. The aerodynamic characteristic of the ring fan based on CFD can represent qualitatively the variation in the measured value. The main flow domain of the ring fan is formed at the tip side of the blade because blade tip vortex is not formed at that location. Therefore, the relative velocity of the ring fan is increased by the circumferential velocity. The sound pressure levels of the ring fan within the frequency band of less than 200 Hz are larger than that of the propeller fan. In the analysis of the wake characteristics, it revealed that Karman vortex shedding occurred in the main flow domain in the frequency domain lower than 200 Hz; the aerodynamic noise of the ring fan in the vortex shedding frequency enlarges due to increase in the relative velocity and the velocity fluctuation.

Virtual reality using guided imagery to create Kanji or Hiragana by computer graphics: I

NASA Astrophysics Data System (ADS)

Ishigame, Masaaki; Miura, Nozomu; Hosaka, Akiko

1997-04-01

We have been studying a kind of word-processor that is able to create Japanese characters, Kanji or Hiragana strings in the cursive style, using an electronic writing brush model. Int his paper, we describe in detail the operation characteristics of the electronic writing brush which we have proposed. We defined a touch shape pattern of the electronic writing brush as a form which is projected as a circle and a cone. The brush goes on certain points of the skeleton of the character figure which is given as skeleton data. The thickness of the line is determined by a diametric variable brush pressure. Our progressive action model can rotate the direction of the writing brush tip corresponding to the difference angle between the direction of brush tip and the direction of the brush movement, and also the softness of the writing brush to express the writing brush method called the side writing brush. The front side and back side of the writing brush can be expressed in a calligraphic drawing. With our technique we can draw characters in actual stroke order on a virtual computer plane as if they are written by an actual writing brush.

2. Oil house, fog signal house and light tower, view ...

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

2. Oil house, fog signal house and light tower, view southwest, east and north sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

On the aerodynamic forces of flapping finite-wings in forward flight: a numerical study

NASA Astrophysics Data System (ADS)

Gonzalo, Alejandro; Uhlmann, Markus; Garcia-Villalba, Manuel; Flores, Oscar

2017-11-01

We study the flow around two flapping wings in forward flight at a low Reynolds number, Re = 500 , with 3D direct numerical simulations. The flow solver used is TUCAN, an in-house code which solves the Navier-Stokes equations for incompressible flow using an immersed boundary method to model the presence of the wings. The wings are rectangular with a NACA0012 airfoil of chord c as a cross-section. They are located side by side at a distance 0.5 c between their inboard tips. The wings flap with respect to an axis parallel to the streamwise velocity, without pitching. The angle of rotation is defined using a sinusoidal function with a reduced frequency k = 1 and an amplitude such that the maximum height of the outboard tips is c in all cases. We perform several simulations varying the aspect ratio of the wings (AR = 2 and 4) and the distance between the inboard tip of the wings and the axis of rotation (R = 0 , 2 and ∞), the latter case corresponding to wings in heaving motion. In this way we can study the variation of the fictitious forces on the wings and the induced spanwise flows, and their relation to the vortical structures on the wing (i.e. leading edge vortex, trailing edge votex, tip vortices) and the resulting aerodynamic forces. This work was funded by project TRA2013-41103-P (Mineco/Feder UE). The simulations were partially performed at the Steinbuch Centre for Computing, Karlsruhe, whose support is thankfully acknowledged.

Real-time rotational ICE imaging of the relationship of the ablation catheter tip and the esophagus during atrial fibrillation ablation.

PubMed

Helms, Adam; West, J Jason; Patel, Amit; Mounsey, J Paul; DiMarco, John P; Mangrum, J Michael; Ferguson, John D

2009-02-01

Atrioesophageal fistula is a rare complication of atrial fibrillation (AF) ablation that should be avoided. We investigated whether rotational intracardiac echocardiography (ICE) can help to minimize ablation close to the esophagus. We studied 41 patients referred for catheter ablation of refractory AF. A rotational ICE catheter was inserted into the (LA) to determine the location of the esophagus. The esophagus was identified to be either adjacent to the pulmonary vein (PV) ostium or to a cuff 2 cm outside the ostium. Circumferential ablation was performed at the PV ostium, with the exact ablation location determined by ICE. The relationship of the catheter tip to the esophagus was imaged during energy delivery, allowing interruption when respiration moved the tip closer to the esophagus. Out of 41 patients, the esophagus was seen near left-sided PVs in 32 and near right-sided PVs in three patients. The median distance from LA endocardium to esophagus was 2.2 mm (range, 1.4-6 mm). In 21 of 35 patients with a closely related esophagus, ablation over the esophagus was avoided by ablating either lateral or medial to the esophagus. In 14 patients, the esophagus could not be avoided, and risk was minimized by limiting lesion size. Significant movement (>10 mm) of the esophagus during the procedure occurred in 3/41 cases. Rotational ICE can accurately determine the distance of ablation sites from the esophagus. Real-time imaging of the relationship of the ablation catheter tip to the esophagus may reduce the incidence of esophageal injury.

Colloidal Random Terpolymers: Controlling Reactivity Ratios of Colloidal Comonomers via Metal Tipping

DOE PAGES

Pavlopoulos, Nicholas G.; Dubose, Jeffrey T.; Hartnett, Erin D.; ...

2016-07-26

We report on a versatile synthetic m-shell nanoparticles (NPs) in the backbone, along with semiconductor CdSe@CdS nanorod (NR), or tetrapod (TP) side chain groups. A seven-step colloidal total synthesis enabled the synthesis of well-defined colloidal comonomers composed of a dipolar Au@CoNP attached to a single CdSe@CdS NR, or TP, where magnetic dipolar associations between Au@CoNP units promoted the formation of colloidal co- or terpolymers. The key step in this synthesis was the ability to photodeposit a single AuNP tip onto CdSe@CdS NR or TP that enables selective seeding of a dipolar CoNP onto the AuNP seed. In conclusion, we showmore » that the variation of the AuNP size directly controlled the size and dipolar character of the CoNP tip, where the size modulation of the Au and Au@CoNP tips is analogous to control of comonomer reactivity ratios in classical copolymerization processes.« less

Crystallographic Analysis of a Japanese Sword by using Bragg Edge Transmission Spectroscopy

NASA Astrophysics Data System (ADS)

Shiota, Yoshinori; Hasemi, Hiroyuki; Kiyanagi, Yoshiaki

Neutron imaging using a pulsed neutron source can give crystallographic information over wide area of a sample by analysing position dependent transmission spectra. With the use of a Bragg edge imaging method we non-destructively obtained crystallographic information of a Japanese sword, signed by Bishu Osafune Norimitsu, in order to know position dependent crystallographic characteristics and to check usefulness of the method for the Japanese sword investigation. Strong texture appeared on the back side. On the other hand in the middle area almost isotropic feature appeared and edge side showed feature between them. Rather isotropic area in the centre area gradually reduced from the grip side to the tip side. The crystallite size was smaller near the edge and became larger towards the back side. The smaller crystallite size will be due to quenching around the edge and this trend disappeared in the grip (nakago) area. The larger crystallite size will be due to strong hammering. Coarse grains were also observed directly as transmission images with the use of a high spatial resolution detector. The spatial distribution of the grains was not uniform but the reason have not been understood. Furthermore, a white area around a tip area was proved to be a void by looking at the Brag edge transmission spectra. This void may be formed during forging process of two kinds of steel. It is suggested that consideration on differences in the texture and the crystallite size depending on position will give information to clarify the manufacturing process, and Bragg edge analysis will be a profitable tool for research of Japanese sword.

Blade tip, finite aspect ratio, and dynamic stall effects on the Darrieus rotor

NASA Astrophysics Data System (ADS)

Paraschivoiu, I.; Desy, P.; Masson, C.

1988-02-01

The objective of the work described in this paper was to apply the Boeing-Vertol dynamic stall model in an asymmetric manner to account for the asymmetry of the flow between the left and right sides of the rotor. This phenomenon has been observed by the flow visualization of a two-straight-bladed Darrieus rotor in the IMST water tunnel. Also introduced into the aerodynamic model are the effects of the blade tip and finite aspect ratio on the aerodynamic performance of the Darrieus wind turbine. These improvements are compatible with the double-multiple-streamtube model and have been included in the CARDAAV computer code for predicting the aerodynamic performance. Very good agreement has been observed between the test data (Sandia 17 m) and theoretical predictions; a significant improvement over the previous dynamic stall model was obtained for the rotor power at low tip speed ratios, while the inclusion of the finite aspect ratio effects enhances the prediction of the rotor power for high tip speed ratios. The tip losses and finite aspect ratio effects were also calculated for a small-scale vertical-axis wind turbine, with a two-straight-bladed (NACA 0015) rotor.

Photonic jet etching: Justifying the shape of optical fiber tip

NASA Astrophysics Data System (ADS)

Abdurrochman, Andri; Zelgowski, Julien; Lecler, Sylvain; Mermet, Frédéric; Tumbelaka, Bernard; Fontaine, Joël

2016-02-01

Photonic jet (PJ) is a low diverging and highly concentrated beam in the shadow side of dielectric particle (cylinder or sphere). The concentration can be more than 200 times higher than the incidence wave. It is a non-resonance phenomenon in the near-field can propagate in a few wavelengths. Many potential applications have been proposed, including PJ etching. Hence, a guided-beam is considered increasing the PJ mobility control. While the others used a combination of classical optical fibers and spheres, we are concerned on a classical optical fiber with spherical tip to generate the PJ. This PJ driven waveguide has been realized using Gaussian mode beam inside the core. It has different variable parameters compared to classical PJ, which will be discussed in correlation with the etching demonstrations. The parameters dependency between the tip and PJ properties are complex; and theoretical aspect of this interaction will be exposed to justify the shape of our tip and optical fiber used in our demonstrations. Methods to achieve such a needed optical fiber tip will also be described. Finally the ability to generate PJ out of the shaped optical fiber will be experimentally demonstrated and the potential applications for material processing will be exposed.

Application of response surface methodology (RSM) and genetic algorithm in minimizing warpage on side arm

NASA Astrophysics Data System (ADS)

Raimee, N. A.; Fathullah, M.; Shayfull, Z.; Nasir, S. M.; Hazwan, M. H. M.

2017-09-01

The plastic injection moulding process produces large numbers of parts of high quality with great accuracy and quickly. It has widely used for production of plastic part with various shapes and geometries. Side arm is one of the product using injection moulding to manufacture it. However, there are some difficulties in adjusting the parameter variables which are mould temperature, melt temperature, packing pressure, packing time and cooling time as there are warpage happen at the tip part of side arm. Therefore, the work reported herein is about minimizing warpage on side arm product by optimizing the process parameter using Response Surface Methodology (RSM) and with additional artificial intelligence (AI) method which is Genetic Algorithm (GA).

The Impact of a 940 nm Diode Laser with Radial Firing Tip and Bare End Fiber Tip on Enterococcus faecalis in the Root Canal Wall Dentin of Bovine Teeth: An In Vitro Study.

PubMed

Schulte-Lünzum, Ruth; Gutknecht, Norbert; Conrads, Georg; Franzen, Rene

2017-07-01

This in vitro study aimed to compare the bactericidal effect of two different laser delivery systems, a radial firing tip (RFT) and bare end fiber tip (BFT) used with the 940 nm diode laser on Enterococcus faecalis inoculated onto bovine radicular dentin. A total of 100 bovine dentin slices with a defined thickness of 500 and 1000 μm were prepared. They were assigned into four test groups together with untreated samples served as control for each slice thickness. The slices were inoculated on one side with 1 μL E. faecalis suspension and laser irradiation was performed indirectly on the opposite side with the 940 nm diode laser delivered with a 200 μm RFT and a BFT at 1 and 1.5 W in continuous wave mode for 8 sec per cycle and repeated four times. After irradiation, the remaining bacteria were detached and the produced suspension was diluted and plated onto blood agar plates with 5% sheep blood and incubated overnight at 37°C in a CO 2 -rich atmosphere. The colony-forming units of E. faecalis were counted and the bacterial reduction was analyzed. The diode laser equipped with RFT fiber design further reduced the number of vital E. faecalis cells significantly compared with BFT design, regardless of the used power and dentin thickness (p < 0.0001). The highest average value of 4 log kills was observed in 500 μm slice thickness irradiated with RFT at 1.5 W. Temperature measurements on the external root surface at 1 mm from the apex did not elicit a harmful temperature elevation in both power settings and fiber designs. Within the studied parameters, 940 nm diode laser in conjugation with RFT showed a satisfactory bactericidal effect without any thermal side effect to the tooth-supporting tissues.

Progress in Modeling Nonlinear Dendritic Evolution in Two and Three Dimensions, and Its Mathematical Justification

NASA Technical Reports Server (NTRS)

Tanveer, S.; Foster, M. R.

2002-01-01

We report progress in three areas of investigation related to dendritic crystal growth. Those items include: 1. Selection of tip features dendritic crystal growth; 2) Investigation of nonlinear evolution for two-sided model; and 3) Rigorous mathematical justification.

Rotating fiber array molecular driver and molecular momentum transfer device constructed therewith

DOEpatents

Milleron, Norman

1983-01-01

A rotating fiber array molecular driver is disclosed which includes a magnetically suspended and rotated central hub to which is attached a plurality of elongated fibers extending radially therefrom. The hub is rotated so as to straighten and axially extend the fibers and to provide the fibers with a tip speed which exceeds the average molecular velocity of fluid molecules entering between the fibers. Molecules colliding with the sides of the rotating fibers are accelerated to the tip speed of the fiber and given a momentum having a directional orientation within a relatively narrow distribution angle at a point radially outward of the hub, which is centered and peaks at the normal to the fiber sides in the direction of fiber rotation. The rotating fiber array may be used with other like fiber arrays or with other stationary structures to form molecular momentum transfer devices such as vacuum pumps, molecular separators, molecular coaters, or molecular reactors.

Developing Barbed Microtip-Based Electrode Arrays for Biopotential Measurement

PubMed Central

Hsu, Li-Sheng; Tung, Shu-Wei; Kuo, Che-Hsi; Yang, Yao-Joe

2014-01-01

This study involved fabricating barbed microtip-based electrode arrays by using silicon wet etching. KOH anisotropic wet etching was employed to form a standard pyramidal microtip array and HF/HNO3 isotropic etching was used to fabricate barbs on these microtips. To improve the electrical conductance between the tip array on the front side of the wafer and the electrical contact on the back side, a through-silicon via was created during the wet etching process. The experimental results show that the forces required to detach the barbed microtip arrays from human skin, a polydimethylsiloxane (PDMS) polymer, and a polyvinylchloride (PVC) film were larger compared with those required to detach microtip arrays that lacked barbs. The impedances of the skin-electrode interface were measured and the performance levels of the proposed dry electrode were characterized. Electrode prototypes that employed the proposed tip arrays were implemented. Electroencephalogram (EEG) and electrocardiography (ECG) recordings using these electrode prototypes were also demonstrated. PMID:25014098

Deep cytoplasmic rearrangements in axis-respecified Xenopus embryos

NASA Technical Reports Server (NTRS)

Denegre, J. M.; Danilchik, M. V.

1993-01-01

In fertilized eggs of the frog Xenopus, the vegetal yolk mass rotates away from the future dorsal side (J. P. Vincent and J. Gerhart, 1987, Dev. Biol. 123, 526-539), and a major rearrangement of the deep animal hemisphere cytoplasm produces a characteristic swirl in the prospective dorsal side (M. V. Danilchik and J. M. Denegre, 1991, Development 111, 845-856). The relationship between this swirl and determination of the dorsal-ventral axis was further investigated by attempting to experimentally separate the positions of the swirl and the dorsal-ventral axis. Eggs were obliquely oriented in the gravity field to respecify the direction of yolk mass rotation and the position of the dorsal-ventral axis. When yolk mass rotation occurred in the absence of a sperm, as in activated eggs, a swirl pattern formed on the side away from which the yolk mass had rotated. In fertilized eggs tipped with the sperm entry point (SEP) down or to the side, swirl patterns were always found to form on the side away from which the yolk mass was displaced. However, in eggs tipped SEP up, in which the yolk mass was forced to rotate away from the SEP, more complicated rearrangements were observed in addition to the rotation-oriented swirl. Because the direction of yolk mass rotation was found to be influenced by both gravity and the actual position of the SEP in obliquely oriented eggs (SEP to the side), such complicated rearrangement patterns may result from opposing forces generated by both yolk mass rotation and the expanding sperm aster. Thus, except in cases in which the influences of SEP position and unit gravity opposed each other, it was not possible to experimentally separate the position of the deep cytoplasmic swirl from the direction of yolk mass rotation, and therefore the position of the prospective dorsal side.

Shape Variation in Aterian Tanged Tools and the Origins of Projectile Technology: A Morphometric Perspective on Stone Tool Function

PubMed Central

Iovita, Radu

2011-01-01

Background Recent findings suggest that the North African Middle Stone Age technocomplex known as the Aterian is both much older than previously assumed, and certainly associated with fossils exhibiting anatomically modern human morphology and behavior. The Aterian is defined by the presence of ‘tanged’ or ‘stemmed’ tools, which have been widely assumed to be among the earliest projectile weapon tips. The present study systematically investigates morphological variation in a large sample of Aterian tools to test the hypothesis that these tools were hafted and/or used as projectile weapons. Methodology/Principal Findings Both classical morphometrics and Elliptical Fourier Analysis of tool outlines are used to show that the shape variation in the sample exhibits size-dependent patterns consistent with a reduction of the tools from the tip down, with the tang remaining intact. Additionally, the process of reduction led to increasing side-to-side asymmetries as the tools got smaller. Finally, a comparison of shape-change trajectories between Aterian tools and Late Paleolithic arrowheads from the North German site of Stellmoor reveal significant differences in terms of the amount and location of the variation. Conclusions/Significance The patterns of size-dependent shape variation strongly support the functional hypothesis of Aterian tools as hafted knives or scrapers with alternating active edges, rather than as weapon tips. Nevertheless, the same morphological patterns are interpreted as one of the earliest evidences for a hafting modification, and for the successful combination of different raw materials (haft and stone tip) into one implement, in itself an important achievement in the evolution of hominin technologies. PMID:22216161

Optical Extinction Measurements of Laser Side-Scatter During Tropical Storm Colin

NASA Technical Reports Server (NTRS)

Lane, John E.; Kasparis, Takis; Metzger, Philip; Michaelides, Silas

2017-01-01

A side-scatter imaging (SSI) technique using a 447 nm, 500 mW laser and a Nikon D80 camera was tested at Kennedy Space Center, Florida during the passing of a rain band associated with Tropical Storm Colin. The June 6, 2016, 22:00 GMT rain event was intense but short-lived owing to the strong west-to-east advection of the rain band. An effort to validate the optical extinction measurement was conducted by setting up a line of three tipping rain gauges along an 80 m east-west path and below the laser beam. Differences between tipping bucket measurements were correlated to the extinction coefficient profile along the lasers path, as determined by the SSI measurement. In order to compare the tipping bucket to the optical extinction data, a Marshall-Palmer DSD model was assumed. Since this was a daytime event, the laser beam was difficult to detect in the camera images, pointing out an important limitation of SSI measurements: the practical limit of DSD density that can be effectively detected and analyzed under daylight conditions using this laser and camera, corresponds to a fairly moderate rainfall rate on the order of 20 mmh (night measurements achieve a much improved sensitivity). The SSI analysis model under test produced promising results, but in order to use the SSI method for routine meteorological studies, improvements to the math model will be required.

Amide I vibrational mode suppression in surface (SERS) and tip (TERS) enhanced Raman spectra of protein specimens

PubMed Central

Kurouski, Dmitry; Postiglione, Thomas; Deckert-Gaudig, Tanja; Deckert, Volker; Lednev, Igor K.

2013-01-01

Surface- and tip-enhanced Raman spectroscopy (SERS and TERS) are modern spectroscopic techniques, which are becoming widely used and show a great potential for the structural characterisation of biological systems. Strong enhancement of the Raman signal through localised surface plasmon resonance enables chemical detection at the single-molecule scale. Enhanced Raman spectra collected from biological specimens, such as peptides, proteins or microorganisms, were often observed to lack the amide I band, which is commonly used as a marker for the interpretation of secondary protein structure. The cause of this phenomenon was unclear for many decades. In this work, we investigated this phenomenon for native insulin and insulin fibrils using both TERS and SERS and compared these spectra to the spectra of well-defined homo peptides. The results indicate that the appearance of the amide I Raman band does not correlate with the protein aggregation state, but is instead determined by the size of the amino acid side chain. For short model peptides, the absence of the amide I band in TERS and SERS spectra correlates with the presence of a bulky side chain. Homo-glycine and -alanine, which are peptides with small side chain groups (H and CH3, respectively), exhibited an intense amide I band in almost 100% of the acquired spectra. Peptides with bulky side chains, such as tyrosine and tryptophan, exhibited the amide I band in 70% and 31% of the acquired spectra, respectively. PMID:23330149

The effect of substrate on electric field enhancement of Tip-enhanced Raman spectroscopy (TERS)

NASA Astrophysics Data System (ADS)

Bahreini, Maryam

2018-01-01

The characterization of materials down to a few-molecule level is a key challenge in nanotechnology. Raman spectroscopy is a powerful method that provides chemical information via nondestructive vibrational fingerprinting. Unfortunately, this method suffers from signal weakness which prevents the study of small quantities. Tip-enhanced Raman spectroscopy (TERS) which combines the chemical sensitivity of Raman spectroscopy (RS) with high spatial resolution of scanning probe microscopy (SPM), provides chemical images of surfaces at the nanometer scale. In this method, irradiation of an SPM tip by a focused laser beam results in enhancement of local electric field via two reasons of localized surface plasmon resonance and lightning rod effect. This enhancement leads to the enhancement in Raman intensity from the sample surface in the vicinity of tip. In all TERS measurements, samples should be located on a substrate. In this paper, the dependence of the electric field enhancement to the substrate has been investigated. In simulations, three-dimensional finite-difference time-domain (3D-FDTD) method is used for numerical solution of Maxwell's equations. Our results show that the electric field enhancement is weak for the tip alone case. Introducing a substrate provides further electric field enhancement via near field electromagnetic dipole-dipole coupling between the tip and substrate. Since the side-illumination geometry is used for laser irradiation, the vertical component of the incident field plays a dominant role in the electric field enhancement. Therefore, the coupling effect between the tip and the substrate is the key contribution to the enhancement. For the case of silicon tip and the gold substrate, the electric field enhancement is improved considerably. There is an optimal tip size for TERS because of the competing effects of the radiation damping and the surface scattering of the tip. The results show the substrate as an effective tool for the improvement of the TERS detection sensitivity.

Hyperspectral imaging for detection of black tip damage in wheat kernels

NASA Astrophysics Data System (ADS)

Delwiche, Stephen R.; Yang, I.-Chang; Kim, Moon S.

2009-05-01

A feasibility study was conducted on the use of hyperspectral imaging to differentiate sound wheat kernels from those with the fungal condition called black point or black tip. Individual kernels of hard red spring wheat were loaded in indented slots on a blackened machined aluminum plate. Damage conditions, determined by official (USDA) inspection, were either sound (no damage) or damaged by the black tip condition alone. Hyperspectral imaging was separately performed under modes of reflectance from white light illumination and fluorescence from UV light (~380 nm) illumination. By cursory inspection of wavelength images, one fluorescence wavelength (531 nm) was selected for image processing and classification analysis. Results indicated that with this one wavelength alone, classification accuracy can be as high as 95% when kernels are oriented with their dorsal side toward the camera. It is suggested that improvement in classification can be made through the inclusion of multiple wavelength images.

Virtual Tool Mark Generation for Efficient Striation Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekstrand, Laura; Zhang, Song; Grieve, Taylor

2014-02-16

This study introduces a tool mark analysis approach based upon 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. An open-source 3D graphics software package is utilized to simulate the marking process as the projection of the tip's geometry in the direction of tool travel. The edge of this projection becomes a virtual tool mark that is compared to cross-sections of the marked plate geometry using the statistical likelihood algorithm introduced by Chumbley et al. In a study with both sides of six screwdriver tips and 34 corresponding marks, the method distinguishedmore » known matches from known nonmatches with zero false-positive matches and two false-negative matches. For matches, it could predict the correct marking angle within ±5–10°. Individual comparisons could be made in seconds on a desktop computer, suggesting that the method could save time for examiners.« less

Comparison of calculated and measured model rotor loading and wake geometry

NASA Technical Reports Server (NTRS)

Johnson, W.

1980-01-01

The calculated blade bound circulation and wake geometry are compared with measured results for a model helicopter rotor in hover and forward flight. Hover results are presented for rectangular tip and ogee tip planform blades. The correlation is quite good when the measured wake geometry characteristics are used in the analysis. Available prescribed wake geometry models are found to give fair predictions of the loading, but they do not produce a reasonable prediction of the induced power. Forward flight results are presented for twisted and untwisted blades. Fair correlation between measurements and calculations is found for the bound circulation distribution on the advancing side. The tip vortex geometry in the vicinity of the advancing blade in forward flight was predicted well by the free wake calculation used, although the wake geometry did not have a significant influence on the calculated loading and performance for the cases considered.

Chip-on-the-tip ultra-compact flexible endoscopic epifluorescence video-microscope for in-vivo imaging in medical and biomedical fields

NASA Astrophysics Data System (ADS)

Matz, Gregor; Messerschmidt, Bernhard; Göbel, Werner; Filser, Severin; Betz, Christian; Kunze, Marcel; Flaemig, Sven; Ehrhardt, André; Irion, Klaus-Martin; Herms, Jochen; Gross, Herbert

2017-02-01

We demonstrate a flexible stand-alone, minimally invasive video-endomicroscope with an outer diameter of 1.6 mm and a length of the rigid tip of 6.7 mm that enables surgeons and biologists to image hardly accessible regions in-vivo in epifluorescence mode. The 60 mg light device improves state-of-the-art objectives by a double deflection approach using a side-fire fiber in combination with spherical microlenses, GRIN-lenses with a specific adapted gradient index profile and an extremely miniaturized chip-on-the-tip camera to achieve an excellent imaging quality. A high NA of 0.7 enables the observation of subcellular features within the entire field of view with a diameter of 183 μm, assure a bright and high-contrast image and promise a good overview during the intervention. Ex-vivo measurements of biological samples confirmed the functionality of the probe.

A prediction of 3-D viscous flow and performance of the NASA Low-Speed Centrifugal Compressor

NASA Technical Reports Server (NTRS)

Moore, John; Moore, Joan G.

1990-01-01

A prediction of the three-dimensional turbulent flow in the NASA Low-Speed Centrifugal Compressor Impeller has been made. The calculation was made for the compressor design conditions with the specified uniform tip clearance gap. The predicted performance is significantly worse than that predicted in the NASA design study. This is explained by the high tip leakage flow in the present calculation and by the different model adopted for tip leakage flow mixing. The calculation gives an accumulation of high losses in the shroud/pressure-side quadrant near the exit of the impeller. It also predicts a region of meridional backflow near the shroud wall. Both of these flow features should be extensive enough in the NASA impeller to allow detailed flow measurements, leading to improved flow modeling. Recommendations are made for future flow studies in the NASA impeller.

A prediction of 3-D viscous flow and performance of the NASA low-speed centrifugal compressor

NASA Technical Reports Server (NTRS)

Moore, John; Moore, Joan G.

1989-01-01

A prediction of the 3-D turbulent flow in the NASA Low-Speed Centrifugal Compressor Impeller has been made. The calculation was made for the compressor design conditions with the specified uniform tip clearance gap. The predicted performance is significantly worse than that predicted in the NASA design study. This is explained by the high tip leakage flow in the present calculation and by the different model adopted for tip leakage flow mixing. The calculation gives an accumulation for high losses in the shroud/pressure-side quadrant near the exit of the impeller. It also predicts a region of meridional backflow near the shroud wall. Both of these flow features should be extensive enough in the NASA impeller to allow detailed flow measurements, leading to improved flow modelling. Recommendations are made for future flow studies in the NASA impeller.

Integrally formed radio frequency quadrupole

DOEpatents

Abbott, Steven R.

1989-01-01

An improved radio frequency quadrupole (10) is provided having an elongate housing (11) with an elongate central axis (12) and top, bottom and two side walls (13a-d) symmetrically disposed about the axis, and vanes (14a-d) formed integrally with the walls (13a-d), the vanes (14a-d) each having a cross-section at right angles to the central axis (12) which tapers inwardly toward the axis to form electrode tips (15a-d) spaced from each other by predetermined distances. Each of the four walls (13a-d), and the vanes (14a-d) integral therewith, is a separate structural element having a central lengthwise plane (16) passing through the tip of the vane, the walls (13a-d) having flat mounting surfaces (17, 18) at right angles to and parallel to the control plane (16), respectively, which are butted together to position the walls and vane tips relative to each other.

Look on the Brighter Side

ERIC Educational Resources Information Center

Cookson, Peter W., Jr.

2004-01-01

In this article, the author shares tips on how to develop a student's creative intelligence and provide activities that enable students to discover their innate abilities. These include making sure that the classroom is a home for students and reflects their hopes and aspirations, creating an effective classroom where every child has the…

77 FR 5577 - Maritime Advisory Committee for Occupational Safety and Health (MACOSH)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-03

... available for inspection and, when permitted, copying, at the OSHA Docket Office at the above address. For...; container handling equipment; semi-tractor tip-over; top/side handler operation safety; stay focused on safety while working on or around cargo handling equipment; safety zones between railcars and cargo...

2D trajectory estimation during free walking using a tiptoe-mounted inertial sensor.

PubMed

Sagawa, Koichi; Ohkubo, Kensuke

2015-07-16

An estimation method for a two-dimensional walking trajectory during free walking, such as forward walking, side stepping and backward walking, was investigated using a tiptoe-mounted inertial sensor. The horizontal trajectory of the toe-tip is obtained by double integration of toe-tip acceleration during the moving phase in which the sensor is rotated before foot-off or after foot-contact, in addition to the swing phase. Special functions that determine the optimum moving phase as the integral duration in every one step are developed statistically using the gait cycle and the resultant angular velocity of dorsi/planter flexion, pronation/supination and inversion/eversion so that the difference between the estimated trajectory and actual one gives a minimum value during free walking with several cadences. To develop the functions, twenty healthy volunteers participated in free walking experiments in which subjects performed forward walking, side stepping to the right, side stepping to the left, and backward walking at 39 m down a straight corridor with several predetermined cadences. To confirm the effect of the developed functions, five healthy subjects participated in the free walking experiment in which each subject performed free walking with different velocities of normal, fast, and slow based on their own assessment in a square course with 7 m side. The experimentally obtained results of free walking with a combination of forward walking, backward walking, and side stepping indicate that the proposed method produces walking trajectory with high precision compared with the constant threshold method which determines swing phase using the size of the angular velocity. Copyright © 2015 Elsevier Ltd. All rights reserved.

High Speed Gear Sized and Configured to Reduce Windage Loss

NASA Technical Reports Server (NTRS)

Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

2013-01-01

A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

Tips for safety in endoscopic submucosal dissection for colorectal tumors

PubMed Central

Naito, Yuji; Murakami, Takaaki; Hirose, Ryohei; Ogiso, Kiyoshi; Inada, Yutaka; Abdul Rani, Rafiz; Kishimoto, Mitsuo; Nakanishi, Masayoshi; Itoh, Yoshito

2017-01-01

In Japan, endoscopic submucosal dissection (ESD) becomes one of standard therapies for large colorectal tumors. Recently, the efficacy of ESD has been reported all over the world. However, it is still difficult even for Japanese experts in some situations. Right-sided location, large tumor size, high degree of fibrosis, difficult manipulation is related with the difficulty. However, improvements on ESD devices, suitable strategies, and increase of operators’ experiences enable us to solve these problems. In this chapter, we introduce recent topics about various difficult factors of colorectal ESD and the tips such as strategy, devices, injection, and traction method [Pocket-creation method (PCM) etc.]. PMID:28616400

Parametric study of rod-pinch diode using particle-in-cell simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, R.; Biswas, D., E-mail: raghav@barc.gov.in; Chandra, R.

2014-07-01

We perform Particle-In-Cell (PIC) simulation of KALI-30 GW pulsed power generator based rod-pinch diode. It is shown that ions emitted from the anode-plasma play a crucial role in diode dynamics. It is found that ions not only help in compensating the space charge due to electron beam, but also lead to enhancement of the local electric field at the side walls of the cathode leading to additional electron emission from the side wall. Electrons emanating from one side wall of the cathode tend to converge at the anode tip. This can be used to design an improved Flash X-ray source.more » (author)« less

Structure and wettability property of the growth and nucleation surfaces of thermally treated freestanding CVD diamond films

NASA Astrophysics Data System (ADS)

Pei, Xiaoqiang; Cheng, Shaoheng; Ma, Yibo; Wu, Danfeng; Liu, Junsong; Wang, Qiliang; Yang, Yizhou; Li, Hongdong

2015-08-01

This paper reports the surface features and wettability properties of the (1 0 0)-textured freestanding chemical vapor deposited (CVD) diamond films after thermal exposure in air at high temperature. Thermal oxidation at proper conditions eliminates selectively nanodiamonds and non-diamond carbons in the films. The growth side of the films contains (1 0 0)-oriented micrometer-sized columns, while its nucleation side is formed of nano-sized tips. The examined wettability properties of the as-treated diamond films reveal a hydrophilicity and superhydrophilicity on the growth surface and nucleation surface, respectively, which is determined by oxygen termination and geometry structure of the surface. When the surface termination is hydrogenated, the wettability of nucleation side converted from superhydrophilicity to high hydrophobicity, while the hydrophilicity of the growth side does not change significantly. The findings open a possibility for realizing freestanding diamond films having not only novel surface structures but also multifunction applications, especially proposed on the selected growth side or nucleation side in one product.

Development of a Tip-Enhanced Near-Field Optical Microscope for Nanoscale Interrogation of Surface Chemistry and Plasmonic Phenomena

NASA Astrophysics Data System (ADS)

Heilman, Alexander Lee

Optical microscopy and spectroscopy are invaluable tools for the physical and chemical characterization of materials and surfaces in a wide range of scientific disciplines. However, the application of conventional optical methods in the study of nanomaterials is inherently limited by diffraction. Tip-enhanced near-field optical microscopy (TENOM) is a hybrid technique that marries optical spectroscopy with scanning probe microscopy to overcome the spatial resolution limit imposed by diffraction. By coupling optical energy into the plasmonic modes of a sharp metal probe tip, a strong, localized optical field is generated near the tip's apex and is used to enhance spectroscopic emissions within a sub-diffraction-limited volume. In this thesis, we describe the design, construction, validation, and application of a custom TENOM instrument with a unique attenuated total reflectance (ATR)-geometry excitation/detection system. The specific goals of this work were: (i) to develop a versatile TENOM instrument capable of investigating a variety of optical phenomena at the nanoscale, (ii) to use the instrument to demonstrate chemical interrogation of surfaces with sub-diffraction-limited spatial resolution (i.e., at super resolution), (iii) to apply the instrument to study plasmonic phenomena that influence spectroscopic enhancement in TENOM measurements, and (iv) to leverage resulting insights to develop systematic improvements that expand the ultimate capabilities of near-field optical interrogation techniques. The TENOM instrument described herein is comprised of three main components: an atomic force microscope (AFM), a side-on confocal Raman microscope, and a novel ATR excitation/detection system. The design of each component is discussed along with the results of relevant validation experiments, which were performed to rigorously assess each component's performance. Finite-difference time-domain (FDTD) optical simulations were also developed and used extensively to evaluate the results of validation studies and to optimize experimental design and instrument performance. By combining and synchronizing the operation of the instrument's three components, we perform a variety of near-field optical experiments that demonstrate the instrument's functionality and versatility. ATR illumination is combined with a plasmonic AFM tip to show that: (i) the tip can quantitatively transduce the optical near-field (evanescent waves) above the surface by scattering photons into the far-field, (ii) the ATR geometry enables excitation and characterization of surface plasmon polaritons (SPPs), whose associated optical fields are shown to enhance Raman scattering from a thin layer of copper phthalocyanine (CuPc), and (iii) SPPs can be used to plasmonically excite the tip for super-resolution chemical imaging of patterned CuPc via tip-enhanced Raman spectroscopy (TERS). ATR-illumination TERS is quantitatively compared with side-on illumination. In both cases, spatial resolution was better than 40 nm and tip-on/tip-off Raman enhancement factors were >6500. Furthermore, ATR illumination was shown to provide similar Raman signal levels at lower "effective'' pump powers due to additional optical energy delivered by SPPs to the active region in the tip-surface gap. We also investigate the sensitivity of the TENOM instrument to changes in the plasmonic properties of the tip-surface system in the strongly-coupled regime at small tip-surface separations. Specifically, we demonstrate detection of a resonant plasmonic tip-surface mode (a gap plasmon) that dramatically influences the optical response of the system, and we use experimental results and FDTD simulations to support a hypothesized mechanism. Moreover, we confirm that the gap plasmon resonance has a strong effect on the enhancement of both fluorescence and Raman scattering, and we propose that this phenomenon could ultimately be exploited to improve sensitivity in super-resolution chemical imaging measurements. Finally, we recommend a straightforward modification to the TENOM instrument that could enable future application of these gap-mode plasmon resonances to increase spectroscopic enhancements by an order of magnitude.

Magnetic energy flow imaging of magnetic recording head with enhanced resolution and sensitivity by A-MFM using high magnetic moment superparamagnetic tip

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Cao, Yongze; Suzuki, Yudai; Yoshimura, Satoru; Saito, Hitoshi

2018-06-01

In this report, the magnetic energy flow of AC magnetic field is imaged from a perpendicular magnetic recording head by alternating magnetic force microscopy (A-MFM) with high magnetic moment Co0.43(GdOx)0.57 superparamagnetic (SP) tip. The present magnetic energy flow imaging phenomenon is able to detect the flow direction of AC magnetic field energy from the recording head. A simple model for the flow direction of the AC magnetic energy is given and revealed that when the AC magnetic field energy from the surface of main pole increases, the energy from the side cross section decreases due to the periodical change of magnetization direction at the main pole area. The A-MFM magnetic energy imaging performance by 100 nm Co0.43(GdOx)0.57 SP tip is compared with the magnetic field imaging with the 25 nm Co0.80Zr0.05Nb0.15 soft magnetic (SM) tip. The spatial resolution measured by Fourier analysis for Co0.43(GdOx)0.57 SP tip is enhanced dramatically to ˜10 nm with low thermal noise, as compared to ˜13 nm by Co0.80Zr0.05Nb0.15 SM tip as well as the previously reported MFM tip. Moreover, the sensitivity and resolution are investigated for a range of head current to confirm the suitability of the magnetic energy flow imaging by Co0.43(GdOx)0.57 SP tip to low as well as high magnetic field source. Further, the A-MFM measurements are performed with the 100 nm Au coated conducting tip to investigate the possibility of electrostatic contribution in magnetic energy imaging by Co0.43(GdOx)0.57 SP tip and revealed that the present A-MFM measurement is free from any electrostatic artifacts. The present magnetic energy flow imaging phenomena with the high magnetic moment Co0.43(GdOx)0.57 SP tip provides an avenue for the analysis of the magnetic field energy component from the head field profile.

Computer simulations suggest direct and stable tip to tip interaction between the outer membrane channel TolC and the isolated docking domain of the multidrug RND efflux transporter AcrB.

PubMed

Schmidt, Thomas H; Raunest, Martin; Fischer, Nadine; Reith, Dirk; Kandt, Christian

2016-07-01

One way by which bacteria achieve antibiotics resistance is preventing drug access to its target molecule for example through an overproduction of multi-drug efflux pumps of the resistance nodulation division (RND) protein super family of which AcrAB-TolC in Escherichia coli is a prominent example. Although representing one of the best studied efflux systems, the question of how AcrB and TolC interact is still unclear as the available experimental data suggest that either both proteins interact in a tip to tip manner or do not interact at all but are instead connected by a hexamer of AcrA molecules. Addressing the question of TolC-AcrB interaction, we performed a series of 100 ns - 1 µs-molecular dynamics simulations of membrane-embedded TolC in presence of the isolated AcrB docking domain (AcrB(DD)). In 5/6 simulations we observe direct TolC-AcrB(DD) interaction that is only stable on the simulated time scale when both proteins engage in a tip to tip manner. At the same time we find TolC opening and closing freely on extracellular side while remaining closed at the inner periplasmic bottleneck region, suggesting that either the simulated time is too short or additional components are required to unlock TolC. Copyright © 2016 Elsevier B.V. All rights reserved.

The leading-edge vortex of yacht sails

NASA Astrophysics Data System (ADS)

Arredondo-Galeana, Abel; Viola, Ignazio Maria

2017-11-01

We experimentally show, for the first time, that a stable Leading-Edge Vortex (LEV) can be formed on an asymmetric spinnaker, which is a high-lift sail used by yachts to sail downwind. We tested a 3D printed rigid sail in a water flume at a chord-based Reynolds number of ca. 104. We found that on the leeward side of the sail (the suction side), the flow separates at the leading edge reattaching further downstream and forming a stable LEV. The LEV grows in diameter from the root to the tip of the sail, where it merges with the tip vortex. We detected the LEV using the γ criterion, and we verified its stability over time. The lift contribution provided by the LEV was computed solving a complex potential model of each sail section. This analysis indicated that the LEV provides a substantial contribution to the total sail's lift. These findings suggest that the maximum lift of low-aspect-ratio wings with a sharp leading edge, such as spinnakers, can be enhanced by promoting a stable LEV. This work was funded by the Consejo Nacional de Ciencia y Tecnologia (CONACYT).

Induction of curvature in maize roots by calcium or by thigmostimulation: role of the postmitotic isodiametric growth zone

NASA Technical Reports Server (NTRS)

Ishikawa, H.; Evans, M. L.

1992-01-01

We examined the response of primary roots of maize (Zea mays L. cv Merit) to unilateral application of calcium with particular attention to the site of application, the dependence on growth rate, and possible contributions of thigmotropic stimulation during application. Unilateral application of agar to the root cap induced negative curvature whether or not the agar contained calcium. This apparent thigmotropic response was enhanced by including calcium in the agar. Curvature away from objects applied unilaterally to the extreme root tip occurred both in intact and detipped roots. When agar containing calcium chloride was applied to one side of the postmitotic isodiametric growth zone ( a region between the apical meristem and the elongation zone), the root curved toward the side of application. This response could not be induced by plain agar. We conclude that curvature away from calcium applied to the root tip results from a thigmotropic response to stimulation during application. In contrast, curvature toward the calcium applied to the postmitotic isodiametric growth zone results from direct calcium-induced inhibition of growth.

Two new species of the genus Aporcelinus Andrássy, 2009 (Nematoda, Dorylaimida, Aporcelaimidae) from Vietnam.

PubMed

Nguyen, Thi Anh Duong; Abolafia, Joaquín; Bonkowski, Michael; Peña-Santiago, Reyes

2016-04-18

Two new species of Aporcelinus from Vietnamese natural habitats are studied, described and illustrated, including line drawings and light microscope (LM) pictures. Aporcelinus paramamillatus sp. n. is characterized by its 1.71-2.14 mm long body, lip region 21-22 μm broad, odontostyle 22-24 μm long at its ventral side, neck 451-503 μm long, uterus tripartite and 71-94 µm long, V = 53-54, tail conical with finely rounded tip, ending in a short peg-like terminus, occasionally slightly re-curved dorsad (24-34 μm, c = 50-77, c' = 0.6-0.9) and unknown male. Aporcelinus paraseychellensis sp. n. is distinguished by its 1.20-1.46 mm long body, lip region 16-18 μm broad, odontostyle 20 μm long at its ventral side, neck 354-368 μm long, uterus tripartite and 176-241 µm long, V = 52-54, tail conical with acute tip and hardly re-curved dorsad, spicules 62 μm long, and 12 regularly spaced ventromedian supplements lacking hiatus.

Interaction potentials of anisotropic nanocrystals from the trajectory sampling of particle motion using in situ liquid phase transmission electron microscopy

DOE PAGES

Chen, Qian; Cho, Hoduk; Manthiram, Karthish; ...

2015-03-23

We demonstrate a generalizable strategy to use the relative trajectories of pairs and groups of nanocrystals, and potentially other nanoscale objects, moving in solution which can now be obtained by in situ liquid phase transmission electron microscopy (TEM) to determine the interaction potentials between nanocrystals. Such nanoscale interactions are crucial for collective behaviors and applications of synthetic nanocrystals and natural biomolecules, but have been very challenging to measure in situ at nanometer or sub-nanometer resolution. Here we use liquid phase TEM to extract the mathematical form of interaction potential between nanocrystals from their sampled trajectories. We show the power ofmore » this approach to reveal unanticipated features of nanocrystal–nanocrystal interactions by examining the anisotropic interaction potential between charged rod-shaped Au nanocrystals (Au nanorods); these Au nanorods assemble, in a tip-to-tip fashion in the liquid phase, in contrast to the well-known side-by-side arrangements commonly observed for drying-mediated assembly. These observations can be explained by a long-range and highly anisotropic electrostatic repulsion that leads to the tip-selective attachment. As a result, Au nanorods stay unassembled at a lower ionic strength, as the electrostatic repulsion is even longer-ranged. Our study not only provides a mechanistic understanding of the process by which metallic nanocrystals assemble but also demonstrates a method that can potentially quantify and elucidate a broad range of nanoscale interactions relevant to nanotechnology and biophysics.« less

Investigation of Unsteady Flow Field in a Low-Speed One and a Half Stage Axial Compressor. Part 2; Effects of Tip Gap Size On the Tip Clearance Flow Structure at Near Stall Operation

NASA Technical Reports Server (NTRS)

Hah, Chunill; Hathaway, Michael; Katz, Joseph

2014-01-01

The primary focus of this paper is to investigate the effect of rotor tip gap size on how the rotor unsteady tip clearance flow structure changes in a low speed one and half stage axial compressor at near stall operation (for example, where maximum pressure rise is obtained). A Large Eddy Simulation (LES) is applied to calculate the unsteady flow field at this flow condition with both a small and a large tip gaps. The numerically obtained flow fields at the small clearance matches fairly well with the available initial measurements obtained at the Johns Hopkins University with 3-D unsteady PIV in an index-matched test facility which renders the compressor blades and casing optically transparent. With this setup, the unsteady velocity field in the entire flow domain, including the flow inside the tip gap, can be measured. The numerical results are also compared with previously published measurements in a low speed single stage compressor (Maerz et al. [2002]). The current study shows that, with the smaller rotor tip gap, the tip clearance vortex moves to the leading edge plane at near stall operating condition, creating a nearly circumferentially aligned vortex that persists around the entire rotor. On the other hand, with a large tip gap, the clearance vortex stays inside the blade passage at near stall operation. With the large tip gap, flow instability and related large pressure fluctuation at the leading edge are observed in this one and a half stage compressor. Detailed examination of the unsteady flow structure in this compressor stage reveals that the flow instability is due to shed vortices near the leading edge, and not due to a three-dimensional separation vortex originating from the suction side of the blade, which is commonly referred to during a spike-type stall inception. The entire tip clearance flow is highly unsteady. Many vortex structures in the tip clearance flow, including the sheet vortex system near the casing, interact with each other. The core tip clearance vortex, which is formed with the rotor tip gap flows near the leading edge, is also highly unsteady or intermittent due to pressure oscillations near the leading edge and varies from passage to passage. For the current compressor stage, the evidence does not seem to support that a classical vortex breakup occurs in any organized way, even with the large tip gap. Although wakes from the IGV influence the tip clearance flow in the rotor, the major characteristics of rotor tip clearance flows in isolated or single stage rotors are observed in this one and a half stage axial compressor.

Impact of an early education multimedia intervention in managing nutrition-related chemotherapy side effects: a pilot study.

PubMed

Thompson, Julie; Silliman, Kathryn; Clifford, Dawn E

2013-12-01

The purpose of the educational intervention was to measure changes in knowledge, perceived benefit of nutrition, and perceived self efficacy in handling side effects of chemotherapy before and after viewing a 15 minute DVD among patients with cancer. A convenience sample of 14 (4 male, 10 female, 61 ± 9 years) patients with cancer, early to chemotherapy, participated in the study. Participants completed a survey with demographic, knowledge items, and perceived health belief and self efficacy statements; viewed the DVD; and were then sent home with a one page handout. Two weeks after the nutrition education intervention, a second survey was completed including an item about tips used. Change was measured using paired t-test and wilcoxon signed rank tests. The mean score on the four knowledge items significantly increased (p < 0.05). No significant differences were noted in statements intended to evaluate changes in perceived health beliefs. However, perceived knowledge and skills related to managing side effects increased (p < 0.05). All participants responded that the DVD was informative and most (n = 11, 79%) responded that it was useful. The majority reported (n = 10, 71%) a tip they used from the DVD. This short multimedia nutrition education intervention was found primarily to increase knowledge and could form a useful component of counseling services for patients undergoing chemotherapy.

Secondary rhinoplasty using flying-bird and vestibular tornado incisions for unilateral cleft lip patients.

PubMed

Matsuya, Tokuzo; Iida, Seiji; Kogo, Mikihiko

2003-08-01

To correct the nasal deformity in cleft lip patients, a new procedure of open rhinoplasty using a "flying-bird" incision in the nostril tip with a vestibule "tornado"-shaped incision in the cleft side is presented. The newly designed vestibular incision produces effective vestibular advancement with the freed lower lateral cartilage. The flying-bird incision makes it possible to produce a suitable nostril tip appearance with symmetrical external nostril vestibules. If the vestibular defect after flap advancement is wide, a full-thickness skin graft is used to give priority for making a good external nostril shape. This procedure is useful for most cleft lip noses, particularly in cases of moderate to severe deformity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Jue-Fei; School of Electronics and Information Engineering, Suzhou Vocational University, Suzhou 215104; Zhou, Liping, E-mail: zhoulp@suda.edu.cn, E-mail: leigao@suda.edu.cn

The electronic transport properties of benzene–porphyrin–benzene (BPB) molecules coupled to gold (Au) electrodes were investigated. By successively removing the front-end Au atoms, several BPB junctions with different molecule-electrode contact symmetries were constructed. The calculated current–voltage (I–V) curves depended strongly on the contact configurations between the BPB molecules and the Au electrodes. In particular, a significant low-voltage negative differential resistance effect appeared at −0.3 V in the junctions with pyramidal electrodes on both sides. Along with the breaking of this tip-contact symmetry, the low-bias negative differential resistance effect gradually disappeared. This tip-contact may be ideal for use in the design ofmore » future molecular devices because of its similarity with experimental processes.« less

Endovascular Catheter for Magnetic Navigation under MR Imaging Guidance: Evaluation of Safety in Vivo at 1.5T

PubMed Central

Hetts, S.W.; Saeed, M.; Martin, A.J.; Evans, L.; Bernhardt, A.F.; Malba, V.; Settecase, F.; Do, L.; Yee, E.J.; Losey, A.; Sincic, R.; Roy, S.; Arenson, R.L.; Wilson, M.W.

2013-01-01

BACKGROUND AND PURPOSE: Endovascular navigation under MR imaging guidance can be facilitated by a catheter with steerable microcoils on the tip. Not only do microcoils create visible artifacts allowing catheter tracking, but also they create a small magnetic moment permitting remote-controlled catheter tip deflection. A side product of catheter tip electrical currents, however, is the heat that might damage blood vessels. We sought to determine the upper boundary of electrical currents safely usable at 1.5T in a coil-tipped microcatheter system. MATERIALS AND METHODS: Alumina tubes with solenoid copper coils were attached to neurovascular microcatheters with heat shrink-wrap. Catheters were tested in carotid arteries of 8 pigs. The catheters were advanced under x-ray fluoroscopy and MR imaging. Currents from 0 mA to 700 mA were applied to test heating and potential vascular damage. Postmortem histologic analysis was the primary endpoint. RESULTS: Several heat-mitigation strategies demonstrated negligible vascular damage compared with control arteries. Coil currents ≤300 mA resulted in no damage (0/58 samples) compared with 9 (25%) of 36 samples for > 300-mA activations (P = .0001). Tip coil activation ≤1 minute and a proximal carotid guide catheter saline drip > 2 mL/minute also had a nonsignificantly lower likelihood of vascular damage. For catheter tip coil activations ≤300 mA for ≤1 minute in normal carotid flow, 0 of 43 samples had tissue damage. CONCLUSIONS: Activations of copper coils at the tip of microcatheters at low currents in 1.5T MR scanners can be achieved without significant damage to blood vessel walls in a controlled experimental setting. Further optimization of catheter design and procedure protocols is necessary for safe remote control magnetic catheter guidance. PMID:23846795

Cut-cell method based large-eddy simulation of tip-leakage flow

NASA Astrophysics Data System (ADS)

Pogorelov, Alexej; Meinke, Matthias; Schröder, Wolfgang

2015-07-01

The turbulent low Mach number flow through an axial fan at a Reynolds number of 9.36 × 105 based on the outer casing diameter is investigated by large-eddy simulation. A finite-volume flow solver in an unstructured hierarchical Cartesian setup for the compressible Navier-Stokes equations is used. To account for sharp edges, a fully conservative cut-cell approach is applied. A newly developed rotational periodic boundary condition for Cartesian meshes is introduced such that the simulations are performed just for a 72° segment, i.e., the flow field over one out of five axial blades is resolved. The focus of this numerical analysis is on the development of the vortical flow structures in the tip-gap region. A detailed grid convergence study is performed on four computational grids with 50 × 106, 250 × 106, 1 × 109, and 1.6 × 109 cells. Results of the instantaneous and the mean fan flow field are thoroughly analyzed based on the solution with 1 × 109 cells. High levels of turbulent kinetic energy and pressure fluctuations are generated by a tip-gap vortex upstream of the blade, the separating vortices inside the tip gap, and a counter-rotating vortex on the outer casing wall. An intermittent interaction of the turbulent wake, generated by the tip-gap vortex, with the downstream blade, leads to a cyclic transition with high pressure fluctuations on the suction side of the blade and a decay of the tip-gap vortex. The disturbance of the tip-gap vortex results in an unsteady behavior of the turbulent wake causing the intermittent interaction. For this interaction and the cyclic transition, two dominant frequencies are identified which perfectly match with the characteristic frequencies in the experimental sound power level and therefore explain their physical origin.

Rectangle-capped and tilted micropillar array for enhanced anisotropic anti-shearing in biomimetic adhesion

PubMed Central

Wang, Yue; Li, Xiangming; Tian, Hongmiao; Hu, Hong; Tian, Yu; Shao, Jinyou; Ding, Yucheng

2015-01-01

Dry adhesion observed in the feet of various small creatures has attracted considerable attention owing to the unique advantages such as self-cleaning, adaptability to rough surfaces along with repeatable and reversible adhesiveness. Among these advantages, for practical applications, proper detachability is critical for dry adhesives with artificial microstructures. In this study, we present a microstructured array consisting of both asymmetric rectangle-capped tip and tilted shafts, which produce an orthogonal anisotropy of the shearing strength along the long and short dimensions of the tip, with a maximum anti-shearing in the two directions along the longer dimension. Meanwhile, the tilt feature can enhance anisotropic shearing adhesion by increasing shearing strength in the forward shearing direction and decreasing strength in the reverse shearing direction along the short dimension of the tip, leading to a minimum anti-shearing in only one of the two directions along the shorter dimension of the rectangular tip. Such a microstructured adhesive with only one weak shearing direction, leading to well-controlled attachment and detachment of the adhesive, is created in our experiment by conventional double-sided exposure of a photoresist followed by a moulding process. PMID:25808338

Intravascular Ultrasound Guidance for Transjugular Intrahepatic Portosystemic Shunt Procedure in a Swine Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kew, Jacqueline; Davies, Roger P.

2004-01-15

A new method is described for guiding hepato-portalvenous puncture using a longitudinal side-view intravascular ultrasound(L-IVUS) transducer to assist in the performance of transjugularintrahepatic portosystemic shunt (TIPS) in three Australian swine.Simultaneous L-IVUS with an AcuNav (registered) 5-10 MHz 10 Fr transducer(Acuson Corporation, Mountain View, CA, USA) and fluoroscopy guidance was used to image and monitor the hepatic to portal venous puncture,dilatation of the tract, and deployment of the TIPS stent. Flow through the shunt could be demonstrated with both L-IVUS and angiography. TIPS was successful in all swine. The time for portal vein puncture once the target portal vein was identifiedmore » was reduced at each attempt. The number of portal vein puncture attempts was 2, 1, and 1. No post-procedural complication was evident. L-IVUS-guided TIPS is practical and has the potential to improve safety by permitting simultaneous ultrasound and fluoroscopic imaging of the needle and target vascular structures. This technique allows for a more streamlined approach to TIPS, decreasing the fluoroscopic time (hence,decreasing the radiation exposure to the staff and patient) and anesthetic time. In addition, there are improved safety benefits obviating the need for wedged portography, facilitating avoidance of bile duct and hepatic arterial puncture, and minimizing hepatic injury by decreasing liver capsular puncture and the attendant risks.« less

Non-tip auditory-nerve responses that are suppressed by low-frequency bias tones originate from reticular lamina motion.

PubMed

Nam, Hui; Guinan, John J

2017-12-14

Recent cochlear mechanical measurements show that active processes increase the motion response of the reticular lamina (RL) at frequencies more than an octave below the local characteristic frequency (CF) for CFs above 5 kHz. A possible correlate is that in high-CF (>5 kHz) auditory-nerve (AN) fibers, responses to frequencies 1-3 octaves below CF ("tail" frequencies) can be inhibited by medial olivocochlear (MOC) efferents. These results indicate that active processes enhance the sensitivity of tail-frequency RL and AN responses. Perhaps related is that some apical low-CF AN fibers have tuning-curve (TC) "side-lobe" response areas at frequencies above and below the TC-tip that are MOC inhibited. We hypothesized that the tail and side-lobe responses are enhanced by the same active mechanisms as CF cochlear amplification. If responses to CF, tail-frequency, and TC-side-lobe tones are all enhanced by prestin motility controlled by outer-hair-cell (OHC) transmembrane voltage, then they should depend on OHC stereocilia position in the same way. To test this, we cyclically changed the OHC-stereocilia mechano-electric-transduction (MET) operating point with low-frequency "bias" tones (BTs) and increased the BT level until the BT caused quasi-static OHC MET saturation that reduced or "suppressed" the gain of OHC active processes. While measuring cat AN-fiber responses, 50 Hz BT level series, 70-120 dB SPL, were run alone and with CF tones, or 2.5 kHz tail-frequency tones, or side-lobe tones. BT-tone-alone responses were used to exclude BT sound levels that produced AN responses that might obscure BT suppression. Data were analyzed to show the BT phase that suppressed the tone responses at the lowest sound level. We found that AN responses to CF, tail-frequency, and side-lobe tones were suppressed at the same BT phase in almost all cases. The data are consistent with the enhancement of responses to CF, tail-frequency, and side-lobe tones all being due to the same OHC-stereocilia MET-dependent active process. Thus, OHC active processes enhance AN responses at frequencies outside of the cochlear-amplified TC-tip region in both high- and low-frequency cochlear regions. The data are consistent with the AN response enhancements being due to enhanced RL motion that drives IHC-stereocilia deflection by traditional RL-TM shear and/or by changing the RL-TM gap. Since tail-frequency basilar membrane (BM) motion is not actively enhanced, the tail-frequency IHC drive is from a vibrational mode little present on the BM, not a "second filter" of BM motion. Copyright © 2017 Elsevier B.V. All rights reserved.

PIV Measurements on a Blowing Flap

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Stead, Daniel J.

2004-01-01

PIV measurements of the flow in the region of a flap side edge are presented for several blowing flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main-element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the vortex system or accelerated the merging of the side vortex to the flap top surface. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

Biometry of the hypospadic penis after hormone therapy (testosterone and estrogen): A randomized, double-blind controlled trial.

PubMed

Paiva, Kelly Christina de Castro; Bastos, André Netto; Miana, Laura Pimenta; Barros, Eveline de Souza; Ramos, Plínio Santos; Miranda, Lara Meneguelli; Faria, Natália Maia; Avarese de Figueiredo, André; de Bessa, José; Netto, José Murillo B

2016-08-01

The use of preoperative hormonal stimulation before hypospadias surgery aims to increase penile size and achieve better surgical results; however, the rules are not clear in the literature. We evaluated the effects of topical testosterone and estrogen in the hypospadic penis regarding biometric measures, side effects, and serum hormonal levels. To our knowledge, this is the first study using estradiol prior to hypospadias surgery. Sixty-nine children with hypospadias were randomly divided into three study groups: a control group (CG) of 17 children given placebo cream; a testosterone group (TG) of 28 children who used 1% testosterone propionate; and an estradiol group (EG) of 24 children using 0.01% estradiol. All subjects applied the topical ointment on the entire penis, twice daily for 30 days before surgical correction. Biometric evaluation of the penis included penile length and diameter, glans diameter, distance from the urethral meatus to the tip, and the width of the urethral plate. These measurements as well as serum hormone level, and side effects were evaluated prior to hormone use, and 30 and 90 days after. After 30 days an increase in penile diameter and length and diameter of the glans were observed in TG (p < 0.05). The width of the urethral plate and distance from meatus to the tip increased in TG, although not significantly. The most frequent side effects were appearance of pubic hair and darkening of the genital skin, mainly in TG, but these were transient and disappeared after 90 days of treatment. No significant variations were seen in serum hormonal levels (Table). As in previous studies, an increase in penile length and diameter, and glans diameter was observed with the use of testosterone. Proximal urethral plate width and distance from the meatus to the tip of the penis had a tendency to increase also in TG. Estradiol did not change biometric measure of the penis. Few side effects occurred after both hormones, and any that did improved after 90 days follow-up and did not change hormone serum levels. Preoperative use of topical testosterone increases penile size, diameter of the penis and glans. The use of estradiol does not change penile biometry. Side effects occur mainly with the use of testosterone and are transient. No significant and persistent hormonal changes were observed. Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis.

PubMed

Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

2018-01-01

Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation.

UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis

PubMed Central

Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

2018-01-01

Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation. PMID:29868074

An Airplane Design having a Wing with Fuselage Attached to Each Tip

NASA Technical Reports Server (NTRS)

Spearman, Leroy M.

2001-01-01

This paper describes the conceptual design of an airplane having a low aspect ratio wing with fuselages that are attached to each wing tip. The concept is proposed for a high-capacity transport as an alternate to progressively increasing the size of a conventional transport design having a single fuselage with cantilevered wing panels attached to the sides and tail surfaces attached at the rear. Progressively increasing the size of conventional single body designs may lead to problems in some area's such as manufacturing, ground-handling and aerodynamic behavior. A limited review will be presented of some past work related to means of relieving some size constraints through the use of multiple bodies. Recent low-speed wind-tunnel tests have been made of models representative of the inboard-wing concept. These models have a low aspect ratio wing with a fuselage attached to each tip. Results from these tests, which included force measurements, surface pressure measurements, and wake surveys, will be presented herein.

‘Fire hardening’ spear wood does slightly harden it, but makes it much weaker and more brittle

PubMed Central

Chan, Tak Lok

2016-01-01

It is usually assumed that ‘fire hardening’ the tips of spears, as practised by hunter–gatherers and early Homo spp., makes them harder and better suited for hunting. This suggestion was tested by subjecting coppiced poles of hazel to a fire-hardening process and comparing their mechanical properties to those of naturally seasoned poles. A Shore D hardness test showed that fire treatment slightly increased the hardness of the wood, but flexural and impact tests showed that it reduced the strength and work of fracture by 30% and 36%, respectively. These results suggest that though potentially slightly sharper and more durable, fire-hardened tips would actually be more likely to break off when used, as may have been the case with the earliest known wooden tool, the Clacton spear. Fire might first have been used to help sharpen the tips of spears, and fire-hardening would have been a mostly negative side effect, not its primary purpose. PMID:27194289

Analysis of Nonplanar Wing-tip-mounted Lifting Surfaces on Low-speed Airplanes

NASA Technical Reports Server (NTRS)

Vandam, C. P.; Roskam, J.

1983-01-01

Nonplanar wing tip mounted lifting surfaces reduce lift induced drag substantially. Winglets, which are small, nearly vertical, winglike surfaces, are an example of these devices. To achieve reduction in lift induced drag, winglets produce significant side forces. Consequently, these surfaces can seriously affect airplane lateral directional aerodynamic characteristics. Therefore, the effects of nonplanar wing tip mounted surfaces on the lateral directional stability and control of low speed general aviation airplanes were studied. The study consists of a theoretical and an experimental, in flight investigation. The experimental investigation involves flight tests of winglets on an agricultural airplane. Results of these tests demonstrate the significant influence of winglets on airplane lateral directional aerodynamic characteristics. It is shown that good correlations exist between experimental data and theoretically predicted results. In addition, a lifting surface method was used to perform a parametric study of the effects of various winglet parameters on lateral directional stability derivatives of general aviation type wings.

Side-Looking Airborne Radar (SLAR): A Tool for Introductory Physical Geography Courses.

ERIC Educational Resources Information Center

Richason, Benjamin F., Jr.

1980-01-01

Suggests how to use remote sensing techniques and data in geography courses in high school and college as well as in geography research. Tips are presented on using techniques such as topographic maps, vertical aerial photographs in stereo pairs, satellite images, and SLAR images (which are particularly useful in teaching landforms and…

"At Sea": Reversibility in Teaching and Learning

ERIC Educational Resources Information Center

Cavicchi, Elizabeth Mary

2018-01-01

An equal-armed balance at equilibrium--the bar is horizontal--tips into disequilibrium upon displacing a weight. Equilibrium is restored by reversing that move--putting the weight back where it was, or doing the same on the other side. Piaget adopted the idea of equilibration to describe how the intellect, in relating to the world, develops.…

Both Sides Now: Librarians Looking at Information Literacy from High School and College. Tips

ERIC Educational Resources Information Center

Schroeder, Robert

2009-01-01

In October 2007, the Oregon Association of School Libraries (OASL) invited the author to speak at their annual conference. The question they asked him was, "What information literacy and library research skills do academic librarians think entering college freshmen should have?" The author investigates this question in his home state of…

Industry Forum Navy Gold Coast

DTIC Science & Technology

2014-08-13

Commercial customers use industry term - Adapt your marketing strategy to fit your customer -  Marketing should NOT be one-size-fits-all...to the customer’s current needs. Marketing Tips 18 NAVFAC Southwest Marketing Materials Business Cards: - Use both sides. - Make it...NAVFAC Southwest Lora E. Morrow Deputy for Small Business NAVFAC Southwest NAVFAC Southwest Industry Forum Navy Gold Coast August

A comparative study of the debridement efficacy and apical extrusion of dynamic and passive root canal irrigation systems

PubMed Central

2014-01-01

Background Root canal irrigation carries a risk of extrusion of irrigant into the periapical tissues which can be associated with pain, swelling, and tissue damage. Studies have shown less extrusion with sonic or apical negative pressure devices compared with syringe and side-port needle or passive ultrasonic irrigation with continuous irrigant flow. This study aimed to evaluate the effectiveness of the EndoVac irrigation system, regarding 1) debris removal and 2) the control of apically extruded irrigating solution. Methods Fifty extracted human single-rooted teeth were used in this study. The teeth were then randomly divided into three experimental groups according to the type of irrigation used and one control group. In group 1, irrigation was performed using the EndoVac irrigation system. In group 2, irrigation was performed using a 30-gauge, tip-vented irrigation needle. In group 3, irrigation was performed using a 30-gauge, side-vented irrigation needle. The control group received instrumentation with no irrigation to serve as a control for cleaning efficiency. Root canal instrumentation was performed using the Profile NiTi rotary system with a crown-down technique. All of the experimental teeth were irrigated with the same amount of 5.25% sodium hypochlorite. The amount of extruded irrigating solution was then measured by subtracting the post-instrumentation weight from the pre-instrumentation weight using an electronic balance. The cleanliness of debris removal was evaluated using scanning electron microscopy. Results EndoVac irrigation had the least amount of extrusion followed by the side-vented and tip-vented method. The difference between the groups was statistically significant (P <0.01). As for the cleaning results, the debris collection in the EndoVac and tip-vented groups was the least in the apical third. In the control and the side-vented groups, the debris was the greatest in the apical third, but this difference was not significant among the three experimental groups. Conclusions The EndoVac irrigation system extruded significantly less irrigant solution than either needle irrigation system. Debris collection was the least in the apical third for the EndoVac irrigation system. No significant difference was found in the cleaning efficiency among the three irrigation systems. PMID:24512441

Free-Spinning-Tunnel Tests of a 0.057-Scale Model of the Chance Vought XF7U-1 Airplane

NASA Technical Reports Server (NTRS)

Daughtridge, Lee T., Jr.

1948-01-01

An investigation of the spin and recovery characteristics of a 0.057-scale model of the Chance Vought XF7U-1 airplane has been conducted in the Langley 20-foot free-spinning tunnel. The effects of control settings and movements on the erect and inverted spin and recovery characteristics were determined, as were also the effects of extending the wing slats, of center-of-gravity movement, and-of variation in the mass distribution. The investigation also included wing-tip spin-recovery-parachute tests, pilot-escape tests, and rudder-control-force tests. The investigation indicated that the spin and recovery characteristics of the airplane will be satisfactory for all conditions. It was found that a single 4.24-foot (full-scale) parachute when opened alone from the outboard wing tip or two 8.77-foot (full-scale) parachutes when opened simultaneously, one from each wing tip, would effect satisfactory emergency recoveries (the drag coefficients of the parachutes, based on the surface area of the parachute, were 0.83 and 0.70 for the 4.24- and 8.77-foot parachutes, respectively). The towline length in both cases was 25 feet (full scale). Tests results showed that, if the pilot should have to leave the airplane during a spin, he should jump from the outboard side (left side in a right spin) of the cockpit. The rudder-control force necessary for recovery from a spin was found to be rather high but appeared to be within the upper limits of a pilot's capabilities.

Finger tapping impairments are highly sensitive for evaluating upper motor neuron lesions.

PubMed

Shirani, Afsaneh; Newton, Braeden D; Okuda, Darin T

2017-03-21

Identifying highly sensitive and reliable neurological exam components are crucial in recognizing clinical deficiencies. This study aimed to investigate finger tapping performance differences between patients with CNS demyelinating lesions and healthy control subjects. Twenty-three patients with multiple sclerosis or clinically isolated syndrome with infratentorial and/or cervical cord lesions on MRI, and 12 healthy controls were videotaped while tapping the tip of the index finger against the tip and distal crease of the thumb using both the dominant and non-dominant hand. Videos were assessed independently by 10 evaluators (three MS neurologists, four neurology residents, three advanced practice providers). Sensitivity and inter-evaluator reliability of finger tapping interpretations were calculated. A total of 1400 evaluations (four videos per each of the 35 subjects evaluated by 10 independent providers) were obtained. Impairments in finger tapping against the distal thumb crease of the non-dominant hand, identified by neurologists, had the greatest sensitivity (84%, p < 0.001) for detecting impairment. Finger tapping against the thumb crease was more sensitive than the thumb tip across all categories of providers. The best inter-evaluator reliability was associated with neurologists' evaluations for the thumb crease of the non-dominant hand (kappa = 0.83, p < 0.001). Impaired finger tapping against the distal thumb crease of the non-dominant hand was a more sensitive technique for detecting impairments related to CNS demyelinating lesions. Our findings highlight the importance of precise examinations of the non-dominant side where impaired fine motor control secondary to an upper motor injury might be detectable earlier than the dominant side.

Gray Fox (Urocyon cinereoargenteus) ecology and management

USGS Publications Warehouse

Howell, Judd A.

1997-01-01

The gray fox (Urocyon cinereoargenteus) is a petite member of the family Canidae in the order Carnivora with a long muzzle and pointed ears (Samuel and Nelson 1982). The coat of the gray fox is silver gray across the back with significant amounts of rufus along the sides. This characteristic is often confused by people who see the flash of red and assume that the fox is a red fox (Vulpes vulpes). The gray fox has a black tipped tail with a dorsal black stripe that differentiates this species from the kit fox (Vulpes macrotis). The red fox has a white tipped tail. The gray fox weighs between 3-5 kg, occasionally to 7 kg. TL 800-1125, T 275-443, HF 100-150. (Jameson and Peeters 1988).

Herpes Zoster

PubMed Central

Cohen, Jeffrey I.

2016-01-01

A 65-year-old man presents with a rash of 2 days duration over the right forehead with vesicles and pustules, a few lesions on the right side and tip of the nose, and slight blurring in the right eye. The rash was preceded by tingling in the area and is now associated with aching pain. How should this patient be evaluated and treated? PMID:23863052

Tongue Motion Patterns in Post-Glossectomy and Typical Speakers: A Principal Components Analysis

ERIC Educational Resources Information Center

Stone, Maureen; Langguth, Julie M.; Woo, Jonghye; Chen, Hegang; Prince, Jerry L.

2014-01-01

Purpose: In this study, the authors examined changes in tongue motion caused by glossectomy surgery. A speech task that involved subtle changes in tongue-tip positioning (the motion from /i/ to /s/) was measured. The hypothesis was that patients would have limited motion on the tumor (resected) side and would compensate with greater motion on the…

Inside France: Three Missing Pages from Your Students' Textbook.

ERIC Educational Resources Information Center

Conniffe, Patricia, Ed.

This mini-unit seeks to fill the gap in textbooks that exists when teaching about modern France. Many textbooks end their coverage of France with the chapter on World War II. This unit offers high school students a unique introduction to France in the mid-1990s. The mini-unit includes a two-sided poster, teaching tips, and student pages. Student…

Theoretical Calculation of Viscous-Inviscid Transonic Flows.

DTIC Science & Technology

1980-08-01

Taylor Naval Ship Research and Development Center Aviation and Surface Effects Department / (See reverse side) Bethesda, Maryland 20084 ! CONTROLLING...Interactions ... .......... ... 46 18 -ffect of Boundary Layer on Blade Surface Pressures in a Transonic Fan Rotor Tip Section Cascade...complicated by the viscous effect . The strong viscous-inviscid interaction caused by the shock wave thickens the boundary layer rapidly, and the flow eventually

Experimental study on rotating instability mode characteristics of axial compressor tip flow

NASA Astrophysics Data System (ADS)

Tian, Jie; Yao, Dan; Wu, Yadong; Ouyang, Hua

2018-04-01

This paper investigates the rotating instabilities that occurred on the single-stage axial compressor designed for aerodynamic performance validation, which was tested with two sets of circumferential measuring points in combination. Circumferential mode characteristics of compressors are usually too high to be captured experimentally, and aliasing of the circumferential mode order occurs when not enough sensors are used. A calibration and prediction method to capture the higher circumferential mode of unsteady flow in a compressor was proposed. Unsteady pressure fluctuations near the tip region in an axial compressor were studied, and high circumferential mode characteristics were captured on both the blade passing frequency (BPF) and the rotational instability frequency (RIF) under different flow rate conditions based on this novel method. The characteristic RI spectrum with a broadband hump was present in a large range of flow conditions. Both the frequency range and the dominant circumferential mode order decreased as the flow rate decreased. Based on the calibrated mode characteristics, a rotating aerodynamic source model is used to explain the side-by-side peak of RIF spectrum and rotating characteristics of RI. The calibration and prediction method of the high circumferential mode is beneficial for the research of unsteady flow in an axial compressor.

A Site Density Functional Theory for Water: Application to Solvation of Amino Acid Side Chains.

PubMed

Liu, Yu; Zhao, Shuangliang; Wu, Jianzhong

2013-04-09

We report a site density functional theory (SDFT) based on the conventional atomistic models of water and the universality ansatz of the bridge functional. The excess Helmholtz energy functional is formulated in terms of a quadratic expansion with respect to the local density deviation from that of a uniform system and a universal functional for all higher-order terms approximated by that of a reference hard-sphere system. With the atomistic pair direct correlation functions of the uniform system calculated from MD simulation and an analytical expression for the bridge functional from the modified fundamental measure theory, the SDFT can be used to predict the structure and thermodynamic properties of water under inhomogeneous conditions with a computational cost negligible in comparison to that of brute-force simulations. The numerical performance of the SDFT has been demonstrated with the predictions of the solvation free energies of 15 molecular analogs of amino acid side chains in water represented by SPC/E, SPC, and TIP3P models. For theTIP3P model, a comparison of the theoretical predictions with MD simulation and experimental data shows agreement within 0.64 and 1.09 kcal/mol on average, respectively.

Mechanical properties and crack growth behavior of polycrystalline copper using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Qiu, Ren-Zheng; Li, Chi-Chen; Fang, Te-Hua

2017-08-01

This study investigated the mechanical properties and crack propagation behavior of polycrystalline copper using a molecular dynamics simulation. The effects of temperature, grain size, and crack length were evaluated in terms of atomic trajectories, slip vectors, common neighbor analysis, the material’s stress-strain diagram and Young’s modulus. The simulation results show that the grain boundary of the material is more easily damaged at high temperatures and that grain boundaries will combine at the crack tip. From the stress-strain diagram, it was observed that the maximum stress increased as the temperature decreased. In contrast, the maximum stress was reduced by increasing the temperature. With regard to the effect of the grain size, when the grain size was too small, the structure of the sample deformed due to the effect of atomic interactions, which caused the grain boundary structure to be disordered in general. However, when the grain size was larger, dislocations appeared and began to move from the tip of the crack, which led to a new dislocation phenomenon. With regards to the effect of the crack length, the tip of the crack did not affect the sample’s material when the crack length was less than 5 nm. However, when the crack length was above 7.5 nm, the grain boundary was damaged, and twinning structures and dislocations appeared on both sides of the crack tip. This is because the tip of the crack was blunt at first before sharpening due to the dislocation effect.

Helicopter rotor wake geometry and its influence in forward flight. Volume 1: Generalized wake geometry and wake effect on rotor airloads and performance

NASA Technical Reports Server (NTRS)

Egolf, T. A.; Landgrebe, A. J.

1983-01-01

An analytic investigation to generalize wake geometry of a helicopter rotor in steady level forward flight and to demonstrate the influence of wake deformation in the prediction of rotor airloads and performance is described. Volume 1 presents a first level generalized wake model based on theoretically predicted tip vortex geometries for a selected representative blade design. The tip vortex distortions are generalized in equation form as displacements from the classical undistorted tip vortex geometry in terms of vortex age, blade azimuth, rotor advance ratio, thrust coefficient, and number of blades. These equations were programmed to provide distorted wake coordinates at very low cost for use in rotor airflow and airloads prediction analyses. The sensitivity of predicted rotor airloads, performance, and blade bending moments to the modeling of the tip vortex distortion are demonstrated for low to moderately high advance ratios for a representative rotor and the H-34 rotor. Comparisons with H-34 rotor test data demonstrate the effects of the classical, predicted distorted, and the newly developed generalized wake models on airloads and blade bending moments. Use of distorted wake models results in the occurrence of numerous blade-vortex interactions on the forward and lateral sides of the rotor disk. The significance of these interactions is related to the number and degree of proximity to the blades of the tip vortices. The correlation obtained with the distorted wake models (generalized and predicted) is encouraging.

Cold air performance of a tip turbine designed to drive a lift fan. 2: Partial admission

NASA Technical Reports Server (NTRS)

Haas, J. E.; Kofskey, M. G.; Hotz, G. M.; Futral, S. M., Jr.

1977-01-01

Partial admission performance was obtained for a 0.4 linear scale version of the LF460 lift fan turbine over a range of speed from 40 to 140 percent of design equivalent speed and a range of scroll inlet total to diffuser exit static pressure ratio from 2.2 to 5.0. The investigation was conducted in two parts, with each part using a different side of the turbine scroll to simulate loss of a gas generator. Each side had an arc of admission of 180. Results are presented in terms of specific work, torque, mass flow, and efficiency.

Crystal Structure of an Ammonia-Permeable Aquaporin

PubMed Central

Kirscht, Andreas; Kaptan, Shreyas S.; Bienert, Gerd Patrick; Chaumont, François; Nissen, Poul; de Groot, Bert L.; Kjellbom, Per; Gourdon, Pontus; Johanson, Urban

2016-01-01

Aquaporins of the TIP subfamily (Tonoplast Intrinsic Proteins) have been suggested to facilitate permeation of water and ammonia across the vacuolar membrane of plants, allowing the vacuole to efficiently sequester ammonium ions and counteract cytosolic fluctuations of ammonia. Here, we report the structure determined at 1.18 Å resolution from twinned crystals of Arabidopsis thaliana aquaporin AtTIP2;1 and confirm water and ammonia permeability of the purified protein reconstituted in proteoliposomes as further substantiated by molecular dynamics simulations. The structure of AtTIP2;1 reveals an extended selectivity filter with the conserved arginine of the filter adopting a unique unpredicted position. The relatively wide pore and the polar nature of the selectivity filter clarify the ammonia permeability. By mutational studies, we show that the identified determinants in the extended selectivity filter region are sufficient to convert a strictly water-specific human aquaporin into an AtTIP2;1-like ammonia channel. A flexible histidine and a novel water-filled side pore are speculated to deprotonate ammonium ions, thereby possibly increasing permeation of ammonia. The molecular understanding of how aquaporins facilitate ammonia flux across membranes could potentially be used to modulate ammonia losses over the plasma membrane to the atmosphere, e.g., during photorespiration, and thereby to modify the nitrogen use efficiency of plants. PMID:27028365

Microtubule distribution in gravitropic protonemata of the moss Ceratodon

NASA Technical Reports Server (NTRS)

Schwuchow, J.; Sack, F. D.; Hartmann, E.

1990-01-01

Tip cells of dark-grown protonemata of the moss Ceratodon purpureus are negatively gravitropic (grow upward). They possess a unique longitudinal zonation: (1) a tip group of amylochloroplasts in the apical dome, (2) a plastid-free zone, (3) a zone of significant plastid sedimentation, and (4) a zone of mostly non-sedimenting plastids. Immunofluorescence of vertical cells showed microtubules distributed throughout the cytoplasm in a mostly axial orientation extending through all zones. Optical sectioning revealed a close spatial association between microtubules and plastids. A majority (two thirds) of protonemata gravistimulated for > 20 min had a higher density of microtubules near the lower flank compared to the upper flank in the plastid-free zone. This apparent enrichment of microtubules occurred just proximal to sedimented plastids and near the part of the tip that presumably elongates more to produce curvature. Fewer than 5% of gravistimulated protonemata had an enrichment in microtubules near the upper flank, whereas 14% of vertical protonemata were enriched near one of the side walls. Oryzalin and amiprophos-methyl (APM) disrupted microtubules, gravitropism, and normal tip growth and zonation, but did not prevent plastid sedimentation. We hypothesize that a microtubule redistribution plays a role in gravitropism in this protonema. This appears to be the first report of an effect of gravity on microtubule distribution in plants.

Tip-leakage cavitation in the clearance of a 2D hydrofoil with fillets: high-speed visualization and PIV/PTV measurements

NASA Astrophysics Data System (ADS)

Zapryagaev, Ivan I.; Timoshevskiy, Mikhail V.; Pervunin, Konstantin S.

2017-09-01

Tip-clearance cavitation is one of the most aggressive forms of cavitation as it can cause surface erosion of hydraulic machinery elements and, as a result, their fatigue damage and disturb designed operating conditions. At present, the literature lacks for detailed experimental data on the inception and development of this type of cavitation at various flow conditions. In the paper, a tip-leakage cavitation occurring in the clearance between an end face of a 2D hydrofoil (a scaled-down model of guide vanes (GV) of a Francis turbine) and a transparent wall of the test section was studied. The experiments were carried out for different cavitating regimes on the cavitation number and two attack angles of 3° and 9°, with the gap size (tip clearance width) varied in the range from 0.4 to 0.8 mm. In order to determine the cavitation inception conditions and investigate the dynamics of the tip-leakage cavitation, a high-speed visualization was applied. A modified PIV/PTV technique with a diverging laser beam instead of a laser light sheet was used to measure the mean velocity distributions within the gap. It was shown that the cavitation pattern on the suction side of the GV model impacts the dynamics of the leakage flow in the gap but does not affect the sheet cavity formed close to the foil leading edge in the clearance as well as its size and dynamics. When the gap size is increased, the tip-leakage cavitation initiates at higher cavitation numbers or, in other words, conditions for the cavitation occurrence become more favorable.

The structure of the cornified claw sheath in the domesticated cat (Felis catus): implications for the claw-shedding mechanism and the evolution of cornified digital end organs

PubMed Central

Homberger, Dominique G; Ham, Kyungmin; Ogunbakin, Tolulope; Bonin, Jonathan A; Hopkins, Brooke A; Osborn, Michelle L; Hossain, Imtiaz; Barnett, Heath A; Matthews, Kenneth L; Butler, Leslie G; Bragulla, Hermann H

2009-01-01

The morphology of cornified structures is notoriously difficult to analyse because of the extreme range of hardness of their component tissues. Hence, a correlative approach using light microscopy, scanning electron microscopy, three-dimensional reconstructions based on x-ray computed tomography data, and graphic modeling was applied to study the morphology of the cornified claw sheath of the domesticated cat as a model for cornified digital end organs. The highly complex architecture of the cornified claw sheath is generated by the living epidermis that is supported by the dermis and distal phalanx. The latter is characterized by an ossified unguicular hood, which overhangs the bony articular base and unguicular process of the distal phalanx and creates an unguicular recess. The dermis covers the complex surface of the bony distal phalanx but also creates special structures, such as a dorsal dermal papilla that points distally and a curved ledge on the medial and lateral sides of the unguicular process. The hard-cornified external coronary horn and proximal cone horn form the root of the cornified claw sheath within the unguicular recess, which is deeper on the dorsal side than on the medial and lateral sides. As a consequence, their rate of horn production is greater dorsally, which contributes to the overall palmo-apical curvature of the cornified claw sheath. The external coronary and proximal cone horn is worn down through normal use as it is pushed apically. The hard-cornified apical cone horn is generated by the living epidermis enveloping the base and free part of the dorsal dermal papilla. It forms nested horn cones that eventually form the core of the hardened tip of the cornified claw. The sides of the cornified claw sheath are formed by the newly described hard-cornified blade horn, which originates from the living epidermis located on the slanted face of the curved ledge. As the blade horn is moved apically, it entrains and integrates the hard-cornified parietal horn on its internal side. It is covered by the external coronary and proximal cone horn on its external side. The soft-cornified terminal horn extends distally from the parietal horn and covers the dermal claw bed at the tip of the uniguicular process, thereby filling the space created by the converging apical cone and blade horn. The soft-cornified sole horn fills the space between the cutting edges of blade horn on the palmar side of the cornified claw sheath. The superficial soft-cornified perioplic horn is produced on the internal side of the unguicular pleat, which surrounds the root of the cornified claw sheath. The shedding of apical horn caps is made possible by the appearance of microcracks in the superficial layers of the external coronary and proximal cone horn in the course of deformations of the cornified claw sheath, which is subjected to tensile forces during climbing or prey catching. These microcracks propagate tangentially through the coronary horn and do not injure the underlying living epidermal and dermal tissues. This built-in shedding mechanism maintains sharp claw tips and ensures the freeing of the claws from the substrate. PMID:19422432

A Paradigm for Security Metrics in Counterinsurgency

DTIC Science & Technology

2011-06-10

unhealthy form of micromanagement.25 Both sides can cite examples to support their positions however a balanced position might incorporate considerations of...comprehensive assessments of a country or region. The framework includes a useful presentation of drivers of tipping points but does not use the... lifestyle . Native Algerians referred to these people as the black foot, or pieds noir in French. This group wielded disproportionate political power

Ten Important Tips in Treating a Patient with Lumbar Disc Herniation

PubMed Central

Hejrati, Hamid; Ariamanesh, Shahrara

2016-01-01

Lumbar disc herniation is a common spinal disorder that usually responds favorably to conservative treatment. In a small percentage of the patients, surgical decompression is necessary. Even though lumbar discectomy constitutes the most common and easiest spine surgery globally, adverse or even catastrophic events can occur. Appropriate patient selection and effective neural decompression constitute the most important points for better surgical outcomes and avoidance of unpleasant complications. Other important tips include timely performance of magnetic resonance imaging, correct interpretation of scan data, preoperative detection of underlying instability, exclusion of non-discogenic sciatica, determination of the main cause of clinical pathology, avoidance of the wrong side or level, and being sure that the more detailed procedure does not necessarily mean the more effective procedure. PMID:27790328

Aerothermal tests of a 12.5 percent cone at Mach 6.7 for various Reynolds numbers, angles of attack and nose shapes. [conducted in Langley 8-foot high temperature tunnel

NASA Technical Reports Server (NTRS)

Nowak, R. J.; Albertson, C. W.; Hunt, L. R.

1984-01-01

The effects of free-stream unit Reynolds number, angle of attack, and nose shape on the aerothermal environment of a 3-ft basediameter, 12.5 deg half-angle cone were investigated in the Langley 8-foot high temperature tunnel at Mach 6.7. The average total temperature was 3300 R, the freestream unit Reynolds number ranged from 400,000 to 1,400,000 per foot, and the angle of attack ranged from 0 deg to 10 deg. Three nose configurations were tested on the cone: a 3-in-radius tip, a 1-in-radius tip on an ogive frustum, and a sharp tip on an ogive frustum. Surface-pressure and cold-wall heating-rate distributions were obtained for laminar, transitional temperature in the shock layer were obtained. The location of the start of transition moved forward both on windward and leeward sides with increasing free-stream Reynolds numbers, increasing angle of attack, and decreasing nose bluntness.

Investigation of nucleation and growth processes of diamond films by atomic force microscopy

NASA Technical Reports Server (NTRS)

George, M. A.; Burger, A.; Collins, W. E.; Davidson, J. L.; Barnes, A. V.; Tolk, N. H.

1994-01-01

The nucleation and growth of plasma-enhanced chemical-vapor deposited polycrystalline diamond films were studied using atomic force microscopy (AFM). AFM images were obtained for (1) nucleated diamond films produced from depositions that were terminated during the initial stages of growth, (2) the silicon substrate-diamond film interface side of diamond films (1-4 micrometers thick) removed from the original surface of the substrate, and (3) the cross-sectional fracture surface of the film, including the Si/diamond interface. Pronounced tip effects were observed for early-stage diamond nucleation attributed to tip convolution in the AFM images. AFM images of the film's cross section and interface, however, were not highly affected by tip convolution, and the images indicate that the surface of the silicon substrate is initially covered by a small grained polycrystalline-like film and the formation of this precursor film is followed by nucleation of the diamond film on top of this layer. X-ray photoelectron spectroscopy spectra indicate that some silicon carbide is present in the precursor layer.

STM contrast of a CO dimer on a Cu(1 1 1) surface: a wave-function analysis.

PubMed

Gustafsson, Alexander; Paulsson, Magnus

2017-12-20

We present a method used to intuitively interpret the scanning tunneling microscopy (STM) contrast by investigating individual wave functions originating from the substrate and tip side. We use localized basis orbital density functional theory, and propagate the wave functions into the vacuum region at a real-space grid, including averaging over the lateral reciprocal space. Optimization by means of the method of Lagrange multipliers is implemented to perform a unitary transformation of the wave functions in the middle of the vacuum region. The method enables (i) reduction of the number of contributing tip-substrate wave function combinations used in the corresponding transmission matrix, and (ii) to bundle up wave functions with similar symmetry in the lateral plane, so that (iii) an intuitive understanding of the STM contrast can be achieved. The theory is applied to a CO dimer adsorbed on a Cu(1 1 1) surface scanned by a single-atom Cu tip, whose STM image is discussed in detail by the outlined method.

STM contrast of a CO dimer on a Cu(1 1 1) surface: a wave-function analysis

NASA Astrophysics Data System (ADS)

Gustafsson, Alexander; Paulsson, Magnus

2017-12-01

We present a method used to intuitively interpret the scanning tunneling microscopy (STM) contrast by investigating individual wave functions originating from the substrate and tip side. We use localized basis orbital density functional theory, and propagate the wave functions into the vacuum region at a real-space grid, including averaging over the lateral reciprocal space. Optimization by means of the method of Lagrange multipliers is implemented to perform a unitary transformation of the wave functions in the middle of the vacuum region. The method enables (i) reduction of the number of contributing tip-substrate wave function combinations used in the corresponding transmission matrix, and (ii) to bundle up wave functions with similar symmetry in the lateral plane, so that (iii) an intuitive understanding of the STM contrast can be achieved. The theory is applied to a CO dimer adsorbed on a Cu(1 1 1) surface scanned by a single-atom Cu tip, whose STM image is discussed in detail by the outlined method.

Computer-based video digitizer analysis of surface extension in maize roots: kinetics of growth rate changes during gravitropism

NASA Technical Reports Server (NTRS)

Ishikawa, H.; Hasenstein, K. H.; Evans, M. L.

1991-01-01

We used a video digitizer system to measure surface extension and curvature in gravistimulated primary roots of maize (Zea mays L.). Downward curvature began about 25 +/- 7 min after gravistimulation and resulted from a combination of enhanced growth along the upper surface and reduced growth along the lower surface relative to growth in vertically oriented controls. The roots curved at a rate of 1.4 +/- 0.5 degrees min-1 but the pattern of curvature varied somewhat. In about 35% of the samples the roots curved steadily downward and the rate of curvature slowed as the root neared 90 degrees. A final angle of about 90 degrees was reached 110 +/- 35 min after the start of gravistimulation. In about 65% of the samples there was a period of backward curvature (partial reversal of curvature) during the response. In some cases (about 15% of those showing a period of reverse bending) this period of backward curvature occurred before the root reached 90 degrees. Following transient backward curvature, downward curvature resumed and the root approached a final angle of about 90 degrees. In about 65% of the roots showing a period of reverse curvature, the roots curved steadily past the vertical, reaching maximum curvature about 205 +/- 65 min after gravistimulation. The direction of curvature then reversed back toward the vertical. After one or two oscillations about the vertical the roots obtained a vertical orientation and the distribution of growth within the root tip became the same as that prior to gravistimulation. The period of transient backward curvature coincided with and was evidently caused by enhancement of growth along the concave and inhibition of growth along the convex side of the curve, a pattern opposite to that prevailing in the earlier stages of downward curvature. There were periods during the gravitropic response when the normally unimodal growth-rate distribution within the elongation zone became bimodal with two peaks of rapid elongation separated by a region of reduced elongation rate. This occurred at different times on the convex and concave sides of the graviresponding root. During the period of steady downward curvature the elongation zone along the convex side extended farther toward the tip than in the vertical control. During the period of reduced rate of curvature, the zone of elongation extended farther toward the tip along the concave side of the root. The data show that the gravitropic response pattern varies with time and involves changes in localized elongation rates as well as changes in the length and position of the elongation zone. Models of root gravitropic curvature based on simple unimodal inhibition of growth along the lower side cannot account for these complex growth patterns.

Changes in taste bud volume during taste disturbance.

PubMed

Srur, Ehab; Pau, Hans Wilhelm; Just, Tino

2011-08-01

On-line mapping and serial volume measurements of taste buds with confocal laser scanning microscopy provide information on the peripheral gustatory organ over time. We report the volumetric measurements of four selected fungiform papillae over 8 weeks in a 62-year-old man with taste disturbance, which was more apparent on the right than on the left side. In the two papillae on the right side, no taste buds were detected within the fungiform papillae in the sixth and eighth week. During sixth and eighth week, there was no response to the highest presented stimuli in electrogustometry (1 mA) on the right-sided tongue tip nor at the tongue edge. The morphology (shape, diameter) of the fungiform papillae on both sides remained unchanged. Comparison of the time course of the volume changes revealed differences corresponding to gustatory sensitivity. These findings suggest that the time course of volume changes indicated taste disturbance in our patient, rather than morphological changes in the fungiform papillae. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Aerodynamic Analysis of Variable Geometry Raked Wingtips for Mid-Range Transonic Transport Aircraft

NASA Astrophysics Data System (ADS)

Jingeleski, David J.

Previous applications have shown that a wingtip treatment on a commercial airliner will reduce drag and increase fuel efficiency and the most common types of treatment are blended winglets and raked wingtips. With Boeing currently investigating novel designs for its next generation of airliners, a variable geometry raked wingtip novel control effector (VGRWT/NCE) was studied to determine the aerodynamic performance benefits over an untreated wingtip. The Boeing SUGAR design employing a truss-braced wing was selected as the baseline. Vortex lattice method (VLM) and computational fluid dynamics (CFD) software was implemented to analyze the aerodynamic performance of such a configuration applied to a next-generation, transonic, mid-range transport aircraft. Several models were created to simulate various sweep positions for the VGRWT/NCE tip, as well as a baseline model with an untreated wingtip. The majority of investigation was conducted using the VLM software, with CFD used largely as a validation of the VLM analysis. The VGRWT/NCE tip was shown to increase the lift of the wing while also decreasing the drag. As expected, the unswept VGRWT/NCE tip increases the amount of lift available over the untreated wingtip, which will be very beneficial for take-off and landing. Similarly, the swept VGRWT/NCE tip reduced the drag of the wing during cruise compared to the unmodified tip, which will favorably impact the fuel efficiency of the aircraft. Also, the swept VGRWT/NCE tip showed an increase in moment compared to the unmodified wingtip, implying an increase in stability, as well providing an avenue for roll control and gust alleviation for flexible wings. CFD analysis validated VLM as a useful low fidelity tool that yielded quite accurate results. The main results of this study are tabulated "deltas" in the forces and moments on the VGRWT/NCE tip as a function of sweep angle and aileron deflection compared to the baseline wing. A side study of the effects of the joint between the main wing and the movable tip showed that the drag impact can be kept small by careful design.

Beam spot diameter of the near-field scanning electron microscopy.

PubMed

Kyritsakis, A; Xanthakis, J P

2013-02-01

We have examined the beam spot diameter at the anode of the scanning electron microscopy (SEM) in the near-field mode as a function of the anode-tip distance d. The detector lateral resolution of this type of microscopy is approximately equal to this spot diameter. For our calculations we have simulated the apex region of the tip with an ellipsoid of revolution of radii R₁ and R₂ with R₁>R₂ as suggested by TEM images of the realistic tips. We have then solved the Laplace equation to obtain the electrostatic potential and to this we have added a spherical image potential. The calculated electrostatic field is highly asymmetric, being strong along the tip-axis and weakening quickly towards the sides. When a 3-dimensional WKB approximation is used to calculate the electron paths corresponding to such a potential, the latter are shown to bend significantly towards the vertical (tip-axis) direction producing a beam narrowing effect very similar to the beam narrowing effect we discovered for the traditional SEM case. When the values of R₁, R₂ are chosen from fittings to the TEM images of the tips used in the experiments, the beam spot diameter W at the anode (d=25 nm) varies from 12.5 nm to 9 nm depending on the fitted R₁, R₂. These values of W are considerably smaller than previously predicted by calculating solid angles of emission from spherical surfaces (41 nm) but also much closer to the detector lateral resolution (6-7 nm) obtained from differentiating the experimental current step. This trend continued at all other d examined. Furthermore the beam width W was found to decrease quickly with increasing sharpness S=R₁/R₂ of the tip and then saturate. W is also decreasing with decreasing R₁, R₂ with S kept constant. We deduce that the sharpness of the tip is important not only for creating high extraction fields but also for guaranteeing a very small beam spot diameter. Copyright © 2012 Elsevier B.V. All rights reserved.

Irrigant flow during photon-induced photoacoustic streaming (PIPS) using Particle Image Velocimetry (PIV).

PubMed

Koch, Jon D; Jaramillo, David E; DiVito, Enrico; Peters, Ove A

2016-03-01

This study aimed to compare fluid movements generated from photon-induced photoacoustic streaming (PIPS) and passive ultrasonic irrigation (PUI). Particle Image Velocimetry (PIV) was performed using 6-μm melamine spheres in water. Measurement areas were 3-mm-long sections of the canal in the coronal, midroot and apical regions for PIPS (erbium/yttrium-aluminium garnet (Er:YAG) laser set at 15 Hz with 20 mJ), or passive ultrasonic irrigation (PUI, non-cutting insert at 30% unit power) was performed in simulated root canals prepared to an apical size #30/0.04 taper. Fluid movement was analysed directly subjacent to the apical ends of ultrasonic insert or fiber optic tips as well as at midroot and apically. During PUI, measured average velocities were around 0.03 m/s in the immediate vicinity of the sides and tip of the ultrasonic file. Speeds decayed to non-measureable values at a distance of about 2 mm from the sides and tip. During PIPS, typical average speeds were about ten times higher than those measured for PUI, and they were measured throughout the length of the canal, at distances up to 20 mm away. PIPS caused higher average fluid speeds when compared to PUI, both close and distant from the instrument. The findings of this study could be relevant to the debriding and disinfecting stage of endodontic therapy. Irrigation enhancement beyond needle irrigation is relevant to more effectively eradicate microorganisms from root canal systems. PIPS may be an alternative approach due to its ability to create high streaming velocities further away from the activation source compared to ultrasonic activation.

Measurement of Kirchhoff's stress intensity factors in bending plates

NASA Astrophysics Data System (ADS)

Bäcker, D.; Kuna, M.; Häusler, C.

2014-03-01

A measurement method of the stress intensity factors defined by KIRCHHOFF's theory for a crack in a bending plate is shown. For this purpose, a thin piezoelectric polyvinylidene fluoride film (PVDF) is attached to the surface of the cracked plate. The measured electrical voltages are coupled with the load type and the crack tip position relative to the sensor film. Stress intensity factors and the crack tip position can be determined by solving the non-linear inverse problem based on the measured signals. To guarantee solvability of the problem, more measuring electrodes on the film have to be taken in to account. To the developed sensor concept the KIRCHHOFF's plate theory has been applied. In order to connect the electrical signals and the stress intensity factors the stresses near the crack tip have to be written in eigenfunctions (see WILLIAMS [1]). The presented method was verified by means of the example of a straight crack of the length 2a in an infinite isotropic plate under all- side bending. It was found that the positioning of the electrodes is delimited by two radii. On one hand, the measurement points should not be too close to the crack tip. In this area, the Kirchhoff's plate theory cannot be used effectively. On the other hand, the measuring electrodes should be placed at a smaller distance to each other and not too far from the crack tip regarding the convergence radius of the WILLIAMS series expansion. Test calculations on a straight crack in an infinite isotropic plate showed the general applicability of the measurement method.

Is traditional reading of the bedside chest radiograph appropriate to detect intraatrial central venous catheter position?

PubMed

Wirsing, Melanie; Schummer, Claudia; Neumann, Rotraud; Steenbeck, Jörg; Schmidt, Peter; Schummer, Wolfram

2008-09-01

Traditionally, the positioning of central venous catheters (CVCs) outside the right atrium (RA) in patients receiving intensive care is determined by surrogate landmarks on bedside chest radiographs (CXRs). The validity of this method was examined by comparing readings of radiologists with the results of transesophageal echocardiography (TEE). Prospective study at university hospital. Two hundred thirteen adults scheduled for cardiothoracic surgery were randomized to right or left internal jugular vein catheterization under ECG guidance. One senior radiologist and two radiologists in training independently read the CXRs, and determined whether the CVC tip ended in the RA and measured the vertical distance from the CVC tip to the carina (TC-distance). Two hundred twelve CVC tips could be identified by TEE. Only left-sided CVCs (n = 5) ended in the upper RA (2.4%). Three of those patients were shorter than 160 cm. Specificity was 94% for senior radiologist, 44% for the first radiologist in training, and 60% for the second radiologist in training. The TC-distance of intraatrial catheters was 39, 55, 59, 80, and 83 mm, respectively. Thus, a TC-distance < or = 55 mm ensured extraatrial tip position in four of five intraatrial CVCs (80%, p = 0.002). The TC-distance of extraatrial catheters ranged from - 26 to 102 mm. Reading of a bedside CXR alone is not very accurate to identify intraatrial CVC tip position. TC-distance is a helpful marker, and its specificity is as good as that of an experienced radiologist if a cutoff value of 55 mm is chosen.

A novel carbon tipped single micro-optrode for combined optogenetics and electrophysiology

PubMed Central

Vizvári, Attila D.; Bali, Zsolt K.; Márki, Balázs; Nagy, Lili V.; Kónya, Zoltán; Madarász, Dániel; Henn-Mike, Nóra; Varga, Csaba; Hernádi, István

2018-01-01

Optical microelectrodes (optrodes) are used in neuroscience to transmit light into the brain of a genetically modified animal to evoke and record electrical activity from light-sensitive neurons. Our novel micro-optrode solution integrates a light-transmitting 125 micrometer optical fiber and a 9 micrometer carbon monofilament to form an electrical lead element, which is contained in a borosilicate glass sheathing coaxial arrangement ending with a micrometer-sized carbon tip. This novel unit design is stiff and slender enough to be used for targeting deep brain areas, and may cause less tissue damage compared with previous models. The center-positioned carbon fiber is less prone to light-induced artifacts than side-lit metal microelectrodes previously presented. The carbon tip is capable of not only recording electrical signals of neuronal origin but can also provide valuable surface area for electron transfer, which is essential in electrochemical (voltammetry, amperometry) or microbiosensor applications. We present details of design and manufacture as well as operational examples of the newly developed single micro-optrode, which includes assessments of 1) carbon tip length–impedance relationship, 2) light transmission capabilities, 3) photoelectric artifacts in carbon fibers, 4) responses to dopamine using fast-scan cyclic voltammetry in vivo, and 5) optogenetic stimulation and spike or local field potential recording from the rat brain transfected with channelrhodopsin-2. With this work, we demonstrate that our novel carbon tipped single micro-optrode may open up new avenues for use in optogenetic stimulation when needing to be combined with extracellular recording, electrochemical, or microbiosensor measurements performed on a millisecond basis. PMID:29513711

Cellular specificity of the gravitropic motor response in roots

NASA Technical Reports Server (NTRS)

Evans, M. L.; Ishikawa, H.

1997-01-01

A number of features of the gravitropic response of roots are not readily accounted for by the classical Cholodny-Went theory. These include the observations that (i) in the later stages of the response the growth gradient is reversed with no evident reversal of the auxin gradient; (ii) a major component of the acceleration of growth along the upper side occurs in the distal elongation zone (DEZ), a group of cells located between the meristem and the main elongation, not within the central elongation zone; and (iii) the initiation of differential growth in the DEZ appears to be independent of the establishment of auxin asymmetry. Alternative candidates for mediation of differential growth in the DEZ include calcium ions and protons. Gravi-induced curvature is accompanied by polar movement of calcium toward the lower side of the maize root tip and the DEZ is shown to be particularly sensitive to growth inhibition by calcium. Also, gravistimulation of maize roots causes enhanced acid efflux from the upper side of the DEZ. Evidence for gravi-induced modification of ion movements in the root tip includes changes in intracellular potentials and current flow. It is clear that there is more than one motor region in the root with regard to gravitropic responses and there is evidence that the DEZ itself consists of more than one class of responding cells. In order to gain a more complete understanding of the mechanism of gravitropic curvature, the physiological properties of the sub-zones of the root apex need to be thoroughly characterized with regard to their sensitivity to hormones, calcium, acid pH and electrical perturbations.

KSC-2009-1988

NASA Image and Video Library

2009-03-08

CAPE CANAVERAL, Fla. – A roseate spoonbill soars overhead against a deep blue sky covering NASA's Kennedy Space Center in Florida. Mature spoonbills feather the brilliant pink feathers with a white neck and beck and orange tails. Immature birds are white. The spoonbill is readily identified by the straight bill with a broad spatulate tip, which they use to obtain food by sweeping from side to side and scooping up whatever they encounter. They spend much of their time feeding on shrimps and fish in the shallow waters of the Florida Bay and Gulf of Mexico. Roseate spoonbills are a common sight throughout Kennedy, which shares a boundary with the Merritt Island National Wildlife Refuge. Photo credit: NASA/Kenny Allen

Self-mutilation of the nose in a schizophrenic patient with Cotard syndrome.

PubMed

Ghaffari-Nejad, Alireza; Kerdegari, Mohammad; Reihani-Kermani, Hamed

2007-10-01

Cotard syndrome is a rare condition, which its main symptom is nihilistic delusion. Self-mutilation of the nose is also a rare condition, which has not been seen in schizophrenic patients with Cotard syndrome. A single case is presented here. A 32-year-old woman who was diagnosed as having schizophrenia and believed that she was dead, cut the tip of her nose. She had no guilt feeling and described her act as a cosmetic surgery. We try to explain how various symptoms that seem to be very far from each other could exist side by side. Misinterpretation of her face is suggested to be the starting point in her complex symptoms.

Effect of pH on ion current through conical nanopores

NASA Astrophysics Data System (ADS)

Chander, M.; Kumar, R.; Kumar, S.; Kumar, N.

2018-05-01

Here, we examined ionic current behavior of conical nanopores at different pH and a fixed ion concentration of potassium halide (KCl). Conical shaped nanopores have been developed by chemical etching technique in polyethylene terephthalate (PET) membrane/foil of thickness 12 micron. For this we employed a self-assembled electrochemical cell having two chambers and the foil was fitted in the centre of cell. The nanopores were produced in the foil using etching and stopping solutions. The experimental results show that ionic current rectification (ICR) occurs through synthesized conical nanopores. Further, ion current increases significantly with increase of voltage from the base side of nanopores to the tip side at fixed pH of electrolyte.

A wind-tunnel investigation of wind-turbine wakes in yawed conditions

NASA Astrophysics Data System (ADS)

Bastankhah, Majid; Porté-Agel, Fernando

2015-06-01

Wind-tunnel experiments were performed to study the performance of a model wind turbine and its wake characteristics in a boundary layer under different operating conditions, including different yaw angles and tip speed ratios. High-resolution particle image- velocimetry (PIV) was used to measure the three velocity components in a horizontal plane at hub height covering a broad streamwise range from upstream of the turbine to the far- wake region. Additionally, thrust and power coefficients of the turbine were measured under different conditions. These power and thrust measurements, together with the highly-resolved flow measurements, enabled us to systematically study different wake properties. The near-wake region is found to have a highly complex structure influenced by different factors such as tip speed ratio and wake rotation. In particular, for higher tip speed ratios, a noticeable speed-up region is observed in the central part of near wake, which greatly affects the flow distribution in this region. In this regard, the behavior of the near wake for turbines with similar thrust coefficients but different tip speed ratios can vary widely. In contrast, it is shown that the mean streamwise velocity in the far wake of the turbine with zero yaw angle has a self-similar Gaussian distribution, and the strength of wake in this region is consistent with the magnitude of the thrust coefficient. With increasing yaw angle, as expected, the power and thrust coefficients decrease, and the wake deflection increases. The measurements also reveal that, in addition to turbulent momentum flux, lateral mean momentum flux boosts the flow entrainment in only one side of the wake, which results in a faster wake recovery in that side. It is also found that the induced velocity upstream of a yawed turbine has a non-symmetric distribution, and its distribution is in agreement with the available model in the literature. Moreover, the results suggest that in order to accurately predict the load distribution in yawed conditions, both normal and tangential (with respect to the rotor plane) components of the induced velocity upstream of the turbine should be taken into account.

Shock Characteristics Measured Upstream of Both a Forward-Swept and an Aft-Swept Fan

NASA Technical Reports Server (NTRS)

Podboy, Gary G.; Krupar, Martin J.; Sutliff, Daniel L.; Horvath, Csaba

2007-01-01

Three different types of diagnostic data-blade surface flow visualization, shroud unsteady pressure, and laser Doppler velocimeter (LDV)--were obtained on two fans, one forward-swept and one aft-swept, in order to learn more about the shocks which propagate upstream of these rotors when they are operated at transonic tip speeds. Flow visualization data are presented for the forward-swept fan operating at 13831 rpm(sub c), and for the aft-swept fan operating at 12500 and 13831 rpm(sub c) (corresponding to tip rotational Mach numbers of 1.07 and 1.19, respectively). The flow visualization data identify where the shocks occur on the suction side of the rotor blades. These data show that at the takeoff speed, 13831 rpm(sub c), the shocks occurring in the tip region of the forward-swept fan are further downstream in the blade passage than with the aft-swept fan. Shroud unsteady pressure measurements were acquired using a linear array of 15 equally-spaced pressure transducers extending from two tip axial chords upstream to 0.8 tip axial chords downstream of the static position of the tip leading edge of each rotor. Such data are presented for each fan operating at one subsonic and five transonic tip speeds. The unsteady pressure data show relatively strong detached shocks propagating upstream of the aft-swept rotor at the three lowest transonic tip speeds, and weak, oblique pressure disturbances attached to the tip of the aft-swept fan at the two highest transonic tip speeds. The unsteady pressure measurements made with the forward-swept fan do not show strong shocks propagating upstream of that rotor at any of the tested speeds. A comparison of the forward-swept and aft-swept shroud unsteady pressure measurements indicates that at any given transonic speed the pressure disturbance just upstream of the tip of the forward-swept fan is much weaker than that of the aft-swept fan. The LDV data suggest that at 12500 and 13831 rpm(sub c), the forward-swept fan swallowed the passage shocks occurring in the tip region of the blades, whereas the aft-swept fan did not. Due to this difference, the flows just upstream of the two fans were found to be quite different at both of these transonic speeds. Nevertheless, despite distinct differences just upstream of the two rotors, the two fan flows were much more alike about one axial blade chord further upstream. As a result, the LDV data suggest that it is unwise to attempt to determine the effect that the shocks have on far field noise by focusing only on measurements (or CFD predictions) made very near the rotor. Instead, these data suggest that it is important to track the shocks throughout the inlet.

Numerical prediction of the spatial and temporal characteristics of the aero-optical disturbance produced by a helicopter in hover

NASA Astrophysics Data System (ADS)

Kelly, Ryan T.

Aero-optical disturbances produced from turbulent compressible flow-fields can seriously degrade the performance of an optical signal. At compressible flight speeds these disturbances stem from the density variations present in turbulent boundary layers and free shear layers; however helicopters typically operate at incompressible speeds, which nearly eliminates the aberrating effect of these flows. For helicopter platforms the sources of aberration originate from the high subsonic flow-field near the rotor blade tips in the form of rotor-tip vortices and from the high temperatures of the engine effluence. During hover the shed rotor-tip vortices and engine effluence convect with the rotor wake encircling the airframe and subsequently a helicopter mounted optical system. The aero-optical effects of the wake beneath a hovering helicopter were analyzed using a combination of Unsteady RANS (URANS) and Large-Eddy Simulations (LES). The spatial and temporal characteristics of the numerical optical wavefronts were compared to full-scale aero-optic experimental measurements. The results indicate that the turbulence of the rotor-tip vortices contributes to the higher order aberrations measured experimentally and that the thermal exhaust plumes effectively limit the optical field-of-regard to forward- and side-looking beam directions. This information along with the computed optical aberrations of the wake can be used to guide the development of adaptive-optic systems or other beam-control approaches.

Single-shot pressure-sensitive paint lifetime measurements on fast rotating blades using an optimized double-shutter technique

NASA Astrophysics Data System (ADS)

Weiss, Armin; Geisler, Reinhard; Schwermer, Till; Yorita, Daisuke; Henne, Ulrich; Klein, Christian; Raffel, Markus

2017-09-01

A pressure-sensitive paint (PSP) system is presented to measure global surface pressures on fast rotating blades. It is dedicated to solve the problem of blurred image data employing the single-shot lifetime method. The efficient blur reduction capability of an optimized double-shutter imaging technique is demonstrated omitting error-prone post-processing or laborious de-rotation setups. The system is applied on Mach-scaled DSA-9A helicopter blades in climb at various collective pitch settings and blade tip Mach and chord Reynolds numbers (M_{ {tip}} = 0.29-0.57; Re_{ {tip}} = 4.63-9.26 × 10^5). Temperature effects in the PSP are corrected by a theoretical approximation validated against measured temperatures using temperature-sensitive paint (TSP) on a separate blade. Ensemble-averaged PSP results are comparable to pressure-tap data on the same blade to within 250 Pa. Resulting pressure maps on the blade suction side reveal spatially high resolved flow features such as the leading edge suction peak, footprints of blade-tip vortices and evidence of laminar-turbulent boundary-layer (BL) transition. The findings are validated by a separately conducted BL transition measurement by means of TSP and numerical simulations using a 2D coupled Euler/boundary-layer code. Moreover, the principal ability of the single-shot technique to capture unsteady flow phenomena is stressed revealing three-dimensional pressure fluctuations at stall.

Unsteady Turbine Blade and Tip Heat Transfer Due to Wake Passing

NASA Technical Reports Server (NTRS)

Ameri, Ali A.; Rigby, David L.; Steinthorsson, Erlendur; Heidmann, James; Fabian, John C.

2007-01-01

The geometry and the flow conditions of the first stage turbine blade of GE s E3 engine have been used to obtain the unsteady three-dimensional blade and tip heat transfer. The isothermal wall boundary condition was used. The effect of the upstream wake of the first stage vane was of interest and was simulated by provision of a gust type boundary condition upstream of the blades. A one blade periodic domain was used. The consequence of this choice was explored in a preliminary study which showed little difference in the time mean heat transfer between 1:1 and 2:3 vane/blade domains. The full three-dimensional computations are of the blade having a clearance gap of 2 percent the span. Comparison between the time averaged unsteady and steady heat transfer is provided. It is shown that there is a significant difference between the steady and time mean of unsteady blade heat transfer in localized regions. The differences on the suction side of the blade in the near hub and near tip regions were found to be rather significant. Steady analysis underestimated the blade heat transfer by as much as 20 percent as compared to the time average obtained from the unsteady analysis. As for the blade tip, the steady analysis and the unsteady analysis gave results to within 2 percent.

Effects of unilateral molar distalization with a modified pendulum appliance.

PubMed

Schütze, Stefan F; Gedrange, Tomas; Zellmann, Markus R; Harzer, Winfried

2007-05-01

The purpose of this study was to evaluate skeletal and dentoalveolar changes due to unilateral distalization and to determine side effects. Cephalograms and dental casts before and after distal movement of the maxillary molars with pendulum appliances in 15 consecutively treated patients (5 girls and 10 boys, 12.06 +/- 1.32 years), were included in this study. The duration of distalization was 8.46 +/- 2.23 months. Cephalometric analysis showed no remarkable growth between the 2 measurement times. The mean value for distalization of the first molars was 3.83 +/- 1.09 mm, with distal tipping of 6.45 degrees . The maxillary second molars were also moved distally 2.83 +/- 1.32 mm and tipped distally 14.7 degrees . No significant changes in the position of the third molars were measured. The mean reciprocal mesial movement of the premolars was 1.18 +/- 1.31 mm, with distal tipping of 1.94 degrees . The incisors moved 0.84 +/- 0.79 mm mesially, with mesial tipping of 0.02 degrees and extrusion of 1.21 mm. There was also a significant influence on the contralateral anchorage unit. However, unilateral distalization reduced incisor proclination and induced moderate distal movement of the contralateral anchorage unit based on rotation around a virtual axis perpendicular to the Nance button. Effective distal molar movement and less anchorage loss at the front teeth are advantages of unilateral distalization.

"The Power of Our Words and Flesh": An Experienced Literacy Coach's Love Letter to Incoming Educators about the Transformational Roles of Relationships and the Body in Learning

ERIC Educational Resources Information Center

Woodcock, Christine; Hakeem, Phyllis

2015-01-01

Framed by the importance of language, and the ways that knowledge is embodied, this study explores the "coaching side" of literacy coaching, providing tips to educators. Phyllis, an experienced coach nearing retirement, wanted to provide insights to incoming teachers as she reflected on the question "Why 'do' we teach, anyway?"…

Theoretical Studies of Interactions between O-Phosphorylated and Standard Amino-Acid Side-Chain Models in Water

PubMed Central

Wiśniewska, Marta; Sobolewski, Emil; Ołdziej, Stanisław; Liwo, Adam; Scheraga, Harold A.; Makowski, Mariusz

2015-01-01

Phosphorylation is a common post-translational modification of the amino-acid side chains (serine, tyrosine, and threonine) that contain hydroxyl groups. The transfer of the negatively charged phosphate group from an ATP molecule to such amino-acid side chains leads to changes in the local conformations of proteins and the pattern of interactions with other amino-acid side-chains. A convenient characteristic of the side chain–side chain interactions in the context of an aqueous environment is the potential of mean force (PMF) in water. A series of umbrella-sampling molecular dynamic (MD) simulations with the AMBER force field were carried out for pairs of O-phosphorylated serine (pSer), threonine (pThr), and tyrosine, (pTyr) with natural amino acids in a TIP3P water model as a solvent at 298 K. The weighted-histogram analysis method was used to calculate the four-dimensional potentials of mean force. The results demonstrate that the positions and depths of the contact minima and the positions and heights of the desolvation maxima, including their dependence on the relative orientation depend on the character of the interacting pairs. More distinct minima are observed for oppositely charged pairs such as, e.g., O-phosphorylated side-chains and positively charged ones, such as the side-chains of lysine and arginine. PMID:26100791

Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

PubMed

Kawaguchi, Jun; Matsuura, Nobuyuki; Kasahara, Masataka; Ichinohe, Tatsuya

2015-02-01

The purpose of this study was to investigate the latency and amplitude of trigeminal somatosensory evoked potentials to clarify how nerve function on the contralateral side is affected after cervical sympathetic block (CSB). Subjects comprised 16 volunteers. For CSB, the tip of a needle was contacted with the transverse process of the sixth cervical vertebra on the right side, and lidocaine was injected. Trigeminal somatosensory evoked potentials were recorded bilaterally from C5/C6 scalp positions. Pupil diameters were also measured. Electrical stimulations were applied to the left-side lower lip, and trigeminal somatosensory evoked potentials waveforms derived from both sides of the scalp were recorded. Then, electrical stimulations were applied to the right-side of the lower lip, and recording was again performed. Recordings were performed at 5, 15, and 30 minutes after CSB. On the CSB side, pupil diameter decreased at 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials at contralateral stimulation showed a prolongation of the latency in both P20 and N25 components on bilateral recording sites 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials' amplitude at contralateral stimulation was smaller than at ipsilateral stimulation 5 minutes after CSB. Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

Nano-optical functionality based on local photoisomerization in photochromic single crystal

NASA Astrophysics Data System (ADS)

Nakagomi, Ryo; Uchiyama, Kazuharu; Kubota, Satoru; Hatano, Eri; Uchida, Kingo; Naruse, Makoto; Hori, Hirokazu

2018-01-01

Towards the construction of functional devices and systems using optical near-field processes, we demonstrate the multivalent features in the path-branching phenomena in a photochromic single crystal observed in optical phase change between colorless (1o) and blue-colored (1c) phases that transmits in subwavelength scale over a macroscopic spatial range associated with local mechanical distortions induced. To observe the near-field optical processes of transmission path branching, we have developed a top-to-bottom double-probe scanning near-field optical microscope capable of nanometer-scale correlation measurements by two individually position-controlled probes that face each other sandwiching the photochromic material. We have experimentally confirmed that a local near-field optical excitation applied to one side of the photochromic crystal by a probe tip resulted in characteristic structures of subwavelength scale around 100 nm or less that are observed by the other probe tip located on the opposite side. The structures are different from those resulting from far-field excitations that are quantitively evaluated by autocorrelations. The results suggest that the mechanical distortion caused by the local phase change in the photochromic crystal suppresses the phase change of the neighboring molecules. This new type of optical-near-field-induced local photoisomerization has the potential to allow the construction of functional devices with multivalent properties for natural intelligence.

Novel 3D-printing technique for caps to enable tailored therapeutic endoscopy.

PubMed

Ko, Weon Jin; Song, Ga Won; Hong, Sung Pyo; Kwon, Chang-il; Hahm, Ki Baik; Cho, Joo Young

2016-03-01

To evaluate the feasibility of a tailored endoscopic cap created using 3D-printing technology that is customized according to esophagogastric lesions of each patient. Tailored endoscopic caps, which were designed and fabricated with a 3D printer, were inserted in 35 patients. The types of cap were side-hole cap made for cap-assisted endoscopic mucosal resection (EMRC), oblique-head cap designed for endoscopic submucosal dissection (ESD), wide-head cap used for Trucut biopsy (TCB), and narrow-tip cap to facilitate peroral endoscopic myotomy (POEM). EMRC in the esophagus and gastroesophageal junction was carried out using a side-hole cap in seven patients. Median total procedure time for successful removal of lesions was 14 min (range 8-50 min). Gastric ESD was carried out using with an oblique-head cap in 16 patients, for which the median total procedure time was 53 min. TCB in the esophagus was done using a wide-head cap in eight patients. While carrying out POEM for tunneling, a narrow-tip cap was used in four patients with achalasia. Based on the current proof-of-concept study, we anticipate that creating a tailored endoscopic cap is feasible for therapeutic endoscopy. © 2015 Japan Gastroenterological Endoscopy Society.

Heat Transfer in a Complex Trailing Edge Passage for a High Pressure Turbine Blade. Part 2:; Simulation Results

NASA Technical Reports Server (NTRS)

Rigby, David L.; Bunker, Ronald S.

2002-01-01

A combined experimental and numerical study to investigate the heat transfer distribution in a complex blade trailing edge passage was conducted. The geometry consists of a two pass serpentine passage with taper toward the trailing edge, as well as from hub to tip. The upflow channel has an average aspect ratio of roughly 14:1, while the exit passage aspect ratio is about 5:1. The upflow channel is split in an interrupted way and is smooth on the trailing edge side of the split and turbulated on the other side. A turning vane is placed near the tip of the upflow channel. Reynolds numbers in the range of 31,000 to 61,000, based on inlet conditions, were simulated numerically. The simulation was performed using the Glenn-HT code, a full three-dimensional Navier-Stokes solver using the Wilcox k-omega turbulence model. A structured multi-block grid is used with approximately 4.5 million cells and average y+ values on the order of unity. Pressure and heat transfer distributions are presented with comparison to the experimental data. While there are some regions with discrepancies, in general the agreement is very good for both pressure and heat transfer.

KSC-98pc1189

NASA Image and Video Library

1998-09-30

KENNEDY SPACE CENTER, FLA. -- Deep Space 1 rests on its work platform after being fitted with thermal insulation. The reflective insulation is designed to protect the spacecraft as this side faces the sun. At either side of the spacecraft are its solar wings, folded for launch. When fully extended, the wings measure 38.6 feet from tip to tip. The first flight in NASA's New Millennium Program, Deep Space 1 is designed to validate 12 new technologies for scientific space missions of the next century. Onboard experiments include a solar-powered ion propulsion engine and software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propelling a spacecraft. Deep Space 1 will complete most of its mission objectives within the first two months, but may also do a flyby of a near-Earth asteroid, 1992 KD, in July 1999. Deep Space 1 will be launched aboard a Boeing Delta 7326 rocket from Launch Pad 17A, Cape Canaveral Air Station, in October. Delta II rockets are medium capacity expendable launch vehicles derived from the Delta family of rockets built and launched since 1960. Since then there have been more than 245 Delta launches

Effect of acupuncture at right Hoku point on the bilateral vibration-induced finger flexion reflex in man.

PubMed

Takakura, N; Kanamaru, A; Sibuya, M; Homma, I

1992-01-01

Vibration applied to the volar side of the finger tip has been reported to induce finger flexion reflex. Acupuncture is reported to inhibit this vibration-induced finger flexion reflex (VFR) in the ipsilateral hand. The purpose of this study was to investigate the effect of unilateral acupuncture in the hand on VFR in both hands. As no systematic study on the relationship between VFR and the force of voluntary contraction with no vibration (Initial Force: IF) has been reported, this relationship was studied prior to the present study on acupuncture. VFR was induced by mechanical vibration on the volar side of the middle finger tip with 10 g to 500 g IF. With approximately 300 g IF, VFR was consistent. Therefore, approximately 300 g IF was applied for VFR induction to study the effect of acupuncture on VFR. A stainless steel needle was inserted into the right Hoku point and remained inserted (in-situ technique) for 10 minutes. VFR in both hands was significantly decreased by acupuncture at the right Hoku point (% control force of VFR: right, 67.8%; left, 74.6%). The present results suggest that acupuncture in the unilateral hand influences the bilateral reflex arc of VFR.

The erosion/corrosion of small superalloy turbine rotors operating in the effluent of a PFB coal combustor

NASA Technical Reports Server (NTRS)

Zellars, G. R.; Benfold, S. M.; Rowe, A. P.; Lowell, C. E.

1979-01-01

Superalloy turbine rotors in a single stage turbine with 6 percent partial admittance were operated in the effluent of a pressurized fluidized bed coal combustor for up to 164 hours. Total mass flow was 300 kg/hr and average particulate loadings ranged from 600 to 2800 ppm for several coal/sorbent combinations. A 5.5 atm turbine inlet gas pressure and inlet gas temperatures from 700 to 800 C yielded absolute gas velocities at the stator exit of about 500 m/s. The angular rotation speed (40,000 rpm) of the six inch diameter rotors was equivalent to a tip speed of about 300 m/s, and average gas velocities relative to the rotating surface ranged from 260 to 330 m/s at mean radius. The rotor erosion pattern reflects heavy particle separation with severe (5 to 500 cm/yr) erosion at the leading edge, pressure side center, and suction side trailing edge at the tip. The erosion distribution pattern provides a spectrum of erosion/oxidation/deposition as a function of blade position. This spectrum includes enhanced oxidation (10 to 100 x air), mixed oxides in exposed depletion zones, sulfur rich oxides in deposition zones, and rugged areas of erosive oxide removal.

KSC-98pc1190

NASA Image and Video Library

1998-09-30

KENNEDY SPACE CENTER, FLA. -- Deep Space 1 rests on its work platform after being fitted with thermal insulation. The dark insulation is designed to protect the side of the spacecraft that faces away from the sun. At either side of the spacecraft are its solar wings, folded for launch. When fully extended, the wings measure 38.6 feet from tip to tip. The first flight in NASA's New Millennium Program, Deep Space 1 is designed to validate 12 new technologies for scientific space missions of the next century. Onboard experiments include a solar-powered ion propulsion engine and software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propelling a spacecraft. Deep Space 1 will complete most of its mission objectives within the first two months, but may also do a flyby of a near-Earth asteroid, 1992 KD, in July 1999. Deep Space 1 will be launched aboard a Boeing Delta 7326 rocket from Launch Pad 17A, Cape Canaveral Air Station, in October. Delta II rockets are medium capacity expendable launch vehicles derived from the Delta family of rockets built and launched since 1960. Since then there have been more than 245 Delta launches

Ion Fluxes in Giant Excised Cardiac Membrane Patches Detected and Quantified with Ion-selective Microelectrodes

PubMed Central

Kang, Tong Mook; Markin, Vladislav S.; Hilgemann, Donald W.

2003-01-01

We have used ion-selective electrodes (ISEs) to quantify ion fluxes across giant membrane patches by measuring and simulating ion gradients on both membrane sides. Experimental conditions are selected with low concentrations of the ions detected on the membrane side being monitored. For detection from the cytoplasmic (bath) side, the patch pipette is oscillated laterally in front of an ISE. For detection on the extracellular (pipette) side, ISEs are fabricated from flexible quartz capillary tubing (tip diameters, 2–3 microns), and an ISE is positioned carefully within the patch pipette with the tip at a controlled distance from the mouth of the patch pipette. Transport activity is then manipulated by solution changes on the cytoplasmic side. Ion fluxes can be quantified by simulating the ion gradients with appropriate diffusion models. For extracellular (intrapatch pipette) recordings, ion diffusion coefficients can be determined from the time courses of concentration changes. The sensitivity and utility of the methods are demonstrated with cardiac membrane patches by measuring (a) potassium fluxes via ion channels, valinomycin, and Na/K pumps; (b) calcium fluxes mediated by Na/Ca exchangers; (c) sodium fluxes mediated by gramicidin and Na/K pumps; and (d) proton fluxes mediated by an unknown electrogenic mechanism. The potassium flux-to-current ratio for the Na/K pump is approximately twice that determined for potassium channels and valinomycin, as expected for a 3Na/2K pump stoichiometery (i.e., 2K/charge moved). For valinomycin-mediated potassium currents and gramicidin-mediated sodium currents, the ion fluxes calculated from diffusion models are typically 10–15% smaller than expected from the membrane currents. As presently implemented, the ISE methods allow reliable detection of calcium and proton fluxes equivalent to monovalent cation currents <1 pA in magnitude, and they allow detection of sodium and potassium fluxes equivalent to <5 pA currents. The capability to monitor ion fluxes, independent of membrane currents, should facilitate studies of both electrogenic and electroneutral ion–coupled transporters in giant patches. PMID:12668735

Turbine airfoil fabricated from tapered extrusions

DOEpatents

Marra, John J

2013-07-16

An airfoil (30) and fabrication process for turbine blades with cooling channels (26). Tapered tubes (32A-32D) are bonded together in a parallel sequence, forming a leading edge (21), a trailing edge (22), and pressure and suction side walls (23, 24) connected by internal ribs (25). The tapered tubes may be extruded without camber to simplify the extrusion process, then bonded along matching surfaces (34), forming a non-cambered airfoil (28), which may be cambered in a hot forming process and cut (48) to length. The tubes may have tapered walls that are thinner at the blade tip (T1) than at the base (T2), reducing mass. A cap (50) may be attached to the blade tip. A mounting lug (58) may be forged (60) on the airfoil base and then machined, completing the blade for mounting in a turbine rotor disk.

A Micro Ultrasonic Scalpel with Modified Stepped Horn

NASA Astrophysics Data System (ADS)

Kurosawa, Minoru; Umehara, Yuji

A transducer for a micro ultrasonic scalpel has been fabricated. The micro ultrasonic scalpel can be used with an endoscope for a non-abdominal operation or micro surgery, for example, through a microscope. The ultrasonic transducer was 9.8 mm long and 2.7 mm wide and has stepped horn to amplify vibration velocity; tip of the horn is 0.6 mm wide. The scalpel operated at the resonance frequency in longitudinal mode of 278 kHz. The piezoelectric material was lead zirconate titanate (PZT) that was deposited by the hydrothermal method. The vibration velocity at the tip of the horn in longitudinal direction was 4.0 m/s with 40Vp-p driving voltage in both side electrodes. To demonstrate a beneficial effect of the scalpel, a cutting test that the transducer was stuck into pork fat was carried out.

A time accurate prediction of the viscous flow in a turbine stage including a rotor in motion

NASA Astrophysics Data System (ADS)

Shavalikul, Akamol

In this current study, the flow field in the Pennsylvania State University Axial Flow Turbine Research Facility (AFTRF) was simulated. This study examined four sets of simulations. The first two sets are for an individual NGV and for an individual rotor. The last two sets use a multiple reference frames approach for a complete turbine stage with two different interface models: a steady circumferential average approach called a mixing plane model, and a time accurate flow simulation approach called a sliding mesh model. The NGV passage flow field was simulated using a three-dimensional Reynolds Averaged Navier-Stokes finite volume solver (RANS) with a standard kappa -- epsilon turbulence model. The mean flow distributions on the NGV surfaces and endwall surfaces were computed. The numerical solutions indicate that two passage vortices begin to be observed approximately at the mid axial chord of the NGV suction surface. The first vortex is a casing passage vortex which occurs at the corner formed by the NGV suction surface and the casing. This vortex is created by the interaction of the passage flow and the radially inward flow, while the second vortex, the hub passage vortex, is observed near the hub. These two vortices become stronger towards the NGV trailing edge. By comparing the results from the X/Cx = 1.025 plane and the X/Cx = 1.09 plane, it can be concluded that the NGV wake decays rapidly within a short axial distance downstream of the NGV. For the rotor, a set of simulations was carried out to examine the flow fields associated with different pressure side tip extension configurations, which are designed to reduce the tip leakage flow. The simulation results show that significant reductions in tip leakage mass flow rate and aerodynamic loss reduction are possible by using suitable tip platform extensions located near the pressure side corner of the blade tip. The computations used realistic turbine rotor inlet flow conditions in a linear cascade arrangement in the relative frame of reference; the boundary conditions for the computations were obtained from inlet flow measurements performed in the AFTRF. A complete turbine stage, including an NGV and a rotor row was simulated using the RANS solver with the SST kappa -- o turbulence model, with two different computational models for the interface between the rotating component and the stationary component. The first interface model, the circumferentially averaged mixing plane model, was solved for a fixed position of the rotor blades relative to the NGV in the stationary frame of reference. The information transferred between the NGV and rotor domains is obtained by averaging across the entire interface. The quasi-steady state flow characteristics of the AFTRF can be obtained from this interface model. After the model was validated with the existing experimental data, this model was not only used to investigate the flow characteristics in the turbine stage but also the effects of using pressure side rotor tip extensions. The tip leakage flow fields simulated from this model and from the linear cascade model show similar trends. More detailed understanding of unsteady characteristics of a turbine flow field can be obtained using the second type of interface model, the time accurate sliding mesh model. The potential flow interactions, wake characteristics, their effects on secondary flow formation, and the wake mixing process in a rotor passage were examined using this model. Furthermore, turbine stage efficiency and effects of tip clearance height on the turbine stage efficiency were also investigated. A comparison between the results from the circumferential average model and the time accurate flow model results is presented. It was found that the circumferential average model cannot accurately simulate flow interaction characteristics on the interface plane between the NGV trailing edge and the rotor leading edge. However, the circumferential average model does give accurate flow characteristics in the NGV domain and the rotor domain with less computational time and computer memory requirements. In contrast, the time accurate flow simulation can predict all unsteady flow characteristics occurring in the turbine stage, but with high computational resource requirements. (Abstract shortened by UMI.)

Influence of Forced Flow on the Dendritic Growth of Fe-C Alloy: 3D vs 2D Simulation

NASA Astrophysics Data System (ADS)

Wang, Weiling; Wang, Zhaohui; Luo, Sen; Ji, Cheng; Zhu, Miaoyong

2017-12-01

A 3D parallel cellular automaton-finite volume method (CA-FVM) model was used to simulate the equiaxed dendritic growth of an Fe-0.82 wt pct C alloy with xy- in- out and xyz- in- out type forced flows and the columnar dendritic growth with y- in- out type forced flow. In addition, the similarities and differences between the results of the 3D and 2D models are discussed and summarized in detail. The capabilities of the 3D and 2D CA-FVM models to predict the dendritic growth of the alloy with forced flow are validated through comparison with the boundary layer correction and Oseen-Ivanstov models, respectively. Because the forced flow can pass around perpendicular arms of the dendrites, the secondary arms at the sides upstream from the perpendicular arms are more developed than those on the upstream side of the upstream arms, especially at higher inlet velocities. In addition, compared to the xy- in- out case, the growth of the downstream arms is less inhibited and the secondary arms are more developed in the xyz- in- out case because of the greater lateral flow around their tips. Compared to the 3D case, the 2D equiaxed dendrites are more asymmetrical and lack secondary arms because of the thicker solute envelope. In the 3D case, the columnar dendrites on the upstream side (left one) are promoted, while the middle and downstream dendrites are inhibited in sequence. However, the sequential inhibition starts on the upstream side in the 2D case. This is mainly because the melt can pass around the upstream branch in 3D space. However, it can only climb over the upstream tip in 2D space. Additionally, the secondary arms show upstream development, which is more significant with increasing inlet velocity. The level of development of the secondary arms is also affected by the decay of the forced flow in the flow direction.

Experimental aerodynamic characteristics for a cylindrical body of revolution with side strakes and various noses at angles of attack from 0 degrees to 58 degrees and Mach numbers from 0.6 to 2.0

NASA Technical Reports Server (NTRS)

Jorgensen, L. H.; Nelson, E. R.

1975-01-01

For a body of revolution with afterbody side strakes, an experimental investigation was conducted in the Ames 6- by 6-Foot Wind Tunnel to determine the effects on the aerodynamic characteristics of forebody geometry, nose strakes, body side strakes, Reynolds number, Mach number, and angle of attack. Aerodynamic force and moment characteristics were measured for the straked cylindrical afterbody (cylinder fineness ratio of 7) with tangent ogive noses of fineness ratio 2.5 to 5.0. In addition, the straked cylinder afterbody was tested with an ogive nose having a rounded tip and an ogive nose with two different nose strake arrangements. The data demonstrate that the aerodynamic characteristics for a body of revolution with side strakes can be significantly affected by changes in nose fineness ratio, nose bluntness, Reynolds number, Mach number, and, of course, angle of attack. Removing the strakes from the cylindrical aftersection greatly decreased the lift, but this removal hardly changed the maximum magnitudes of the undesirable side forces that developed at angles of attack greater than about 25 deg for subsonic Mach numbers.

Effect of piezocision on root resorption associated with orthodontic force: A microcomputed tomography study.

PubMed

Patterson, Braydon M; Dalci, Oyku; Papadopoulou, Alexandra K; Madukuri, Suman; Mahon, Jonathan; Petocz, Peter; Spahr, Axel; Darendeliler, M Ali

2017-01-01

The purpose of this study was to investigate the effect of piezocision on orthodontically induced inflammatory root resorption. Fourteen patients were included in this split-mouth study; 1 side was assigned to piezocision, and the other side served as the control. Vertical corticotomy cuts of 4 to 5 mm in length were performed on either side of each piezocision premolar, and 150-g buccal tipping forces were applied to the premolars. After 4 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography. There was a significantly greater total amount of root resorption seen on the piezocision sides when compared with the control sides (P = 0.029). The piezocision procedure resulted in a 44% average increase in root resorption. In 5 patients, there was noticeable piezocision-related iatrogenic root damage. When that was combined with the orthodontic root resorption found on the piezocision-treated teeth, there was a statistically significant 110% average increase in volumetric root loss when compared with the control side (P = 0.005). The piezocision procedure that initiates the regional acceleratory phenomenon may increase the iatrogenic root resorption when used in conjunction with orthodontic forces. Piezocision applied close to the roots may cause iatrogenic damage to the neighboring roots and should be used carefully. Copyright © 2017.

A dynamic model of a cantilever beam with a closed, embedded horizontal crack including local flexibilities at crack tips

NASA Astrophysics Data System (ADS)

Liu, J.; Zhu, W. D.; Charalambides, P. G.; Shao, Y. M.; Xu, Y. F.; Fang, X. M.

2016-11-01

As one of major failure modes of mechanical structures subjected to periodic loads, embedded cracks due to fatigue can cause catastrophic failure of machineries. Understanding the dynamic characteristics of a structure with an embedded crack is helpful for early crack detection and diagnosis. In this work, a new three-segment beam model with local flexibilities at crack tips is developed to investigate the vibration of a cantilever beam with a closed, fully embedded horizontal crack, which is assumed to be not located at its clamped or free end or distributed near its top or bottom side. The three-segment beam model is assumed to be a linear elastic system, and it does not account for the nonlinear crack closure effect; the top and bottom segments always stay in contact at their interface during the beam vibration. It can model the effects of local deformations in the vicinity of the crack tips, which cannot be captured by previous methods in the literature. The middle segment of the beam containing the crack is modeled by a mechanically consistent, reduced bending moment. Each beam segment is assumed to be an Euler-Bernoulli beam, and the compliances at the crack tips are analytically determined using a J-integral approach and verified using commercial finite element software. Using compatibility conditions at the crack tips and the transfer matrix method, the nature frequencies and mode shapes of the cracked cantilever beam are obtained. The three-segment beam model is used to investigate the effects of local flexibilities at crack tips on the first three natural frequencies and mode shapes of the cracked cantilever beam. A stationary wavelet transform (SWT) method is used to process the mode shapes of the cracked cantilever beam; jumps in single-level SWT decomposition detail coefficients can be used to identify the length and location of an embedded horizontal crack.

Ten tips for receiving feedback effectively in clinical practice

PubMed Central

Algiraigri, Ali H.

2014-01-01

Background Despite being recognized as a fundamental part of the educational process and emphasized for several decades in medical education, the influence of the feedback process is still suboptimal. This may not be surprising, because the focus is primarily centered on only one half of the process – the teachers. The learners are the targets of the feedback process and improvement needs to be shifted. Learners need to be empowered with the skills needed to receive and utilize feedback and compensate for less than ideal feedback delivery due to the busy clinical environment. Methods Based on the available feedback literature and clinical experience regarding feedback, the author developed 10 tips to empower learners with the necessary skills to seek, receive, and handle feedback effectively, regardless of how it is delivered. Although, most of the tips are directed at the individual clinical trainee, this model can be utilized by clinical educators involved in learner development and serve as a framework for educational workshops or curriculum. Results Ten practical tips are identified that specifically address the learner's role in the feedback process. These tips not only help the learner to ask, receive, and handle the feedback, but will also ease the process for the teachers. Collectively, these tips help to overcome most, if not all, of the barriers to feedback and bridge the gaps in busy clinical practices. Conclusions Feedback is a crucial element in the educational process and it is shown that we are still behind in the optimal use of it; thus, learners need to be taught how to better receive and utilize feedback. The focus in medical education needs to balance the two sides of the feedback process. It is time now to invest on the learner's development of skills that can be utilized in a busy day-to-day clinical practice. PMID:25079664

Investigation of Unsteady Flow Behavior in Transonic Compressor Rotors with LES and PIV Measurements

NASA Technical Reports Server (NTRS)

Hah, Chunill; Voges, Melanie; Mueller, Martin; Schiffer, Heinz-Peter

2009-01-01

In the present study, unsteady flow behavior in a modern transonic axial compressor rotor is studied in detail with large eddy simulation (LES) and particle image velocimetry (PIV). The main purpose of the study is to advance the current understanding of the flow field near the blade tip in an axial transonic compressor rotor near the stall and peak-efficiency conditions. Flow interaction between the tip leakage vortex and the passage shock is inherently unsteady in a transonic compressor. Casing-mounted unsteady pressure transducers have been widely applied to investigate steady and unsteady flow behavior near the casing. Although many aspects of flow have been revealed, flow structures below the casing cannot be studied with casing-mounted pressure transducers. In the present study, unsteady velocity fields are measured with a PIV system and the measured unsteady flow fields are compared with LES simulations. The currently applied PIV measurements indicate that the flow near the tip region is not steady even at the design condition. This self-induced unsteadiness increases significantly as the compressor rotor operates near the stall condition. Measured data from PIV show that the tip clearance vortex oscillates substantially near stall. The calculated unsteady characteristics of the flow from LES agree well with the PIV measurements. Calculated unsteady flow fields show that the formation of the tip clearance vortex is intermittent and the concept of vortex breakdown from steady flow analysis does not seem to apply in the current flow field. Fluid with low momentum near the pressure side of the blade close to the leading edge periodically spills over into the adjacent blade passage. The present study indicates that stall inception is heavily dependent on unsteady behavior of the flow field near the leading edge of the blade tip section for the present transonic compressor rotor.

An Experimental and Analytical Study of TIP Clearance Effects in Axial Flow Compressors

DTIC Science & Technology

1991-12-01

increasingly being used for design insight into the flow field. Implementations of the Navier Stokes equations using interacting grids or similar schemes...analytical reason for the existence of a pressure minimum locus lving away from the suction corner is provided by Barclay (1982) in a solution for the...relief at the leading edge on the suction side, grid Sensitivity and similar computational concerns, the computations predict %khat the blade loading

Cruise noise of an advanced counterrotation turboprop measured from an adjacent aircraft

NASA Technical Reports Server (NTRS)

Woodward, Richard P.; Loeffler, Irvin J.; Dittmar, James H.

1988-01-01

Acoustic test results are presented for a full-scale counterrotation demonstrator engine installed on a Boeing 727 aircraft in place of the right-side turbofan engine. Sideline acoustic data were acquired from a Learjet chase aircraft instrumented with noise and wing-tip flush mount microphones. Data are presented for a 47.2-m sideline at several engine operating conditions and flight Mach numbers of 0.50 and 0.72.

Frequency-dependent photothermal measurement of transverse thermal diffusivity of organic semiconductors

NASA Astrophysics Data System (ADS)

Brill, J. W.; Shahi, Maryam; Payne, Marcia M.; Edberg, Jesper; Yao, Y.; Crispin, Xavier; Anthony, J. E.

2015-12-01

We have used a photothermal technique, in which chopped light heats the front surface of a small (˜1 mm2) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid-nitrogen-cooled infrared detector. In our system, the sample is placed directly in front of the detector within its dewar. Because the detector is also sensitive to some of the incident light, which leaks around or through the sample, measurements are made for the detector signal that is in quadrature with the chopped light. Results are presented for layered crystals of semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pn) and for papers of cellulose nanofibrils coated with semiconducting poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (NFC-PEDOT). For NFC-PEDOT, we have found that the transverse diffusivity, smaller than the in-plane value, varies inversely with thickness, suggesting that texturing of the papers varies with thickness. For TIPS-pn, we have found that the interlayer diffusivity is an order of magnitude larger than the in-plane value, consistent with previous estimates, suggesting that low-frequency optical phonons, presumably associated with librations in the TIPS side groups, carry most of the heat.

Root gravitropism is regulated by a transient lateral auxin gradient controlled by a tipping-point mechanism

PubMed Central

Band, Leah R.; Wells, Darren M.; Larrieu, Antoine; Sun, Jianyong; Middleton, Alistair M.; French, Andrew P.; Brunoud, Géraldine; Sato, Ethel Mendocilla; Wilson, Michael H.; Péret, Benjamin; Oliva, Marina; Swarup, Ranjan; Sairanen, Ilkka; Parry, Geraint; Ljung, Karin; Beeckman, Tom; Garibaldi, Jonathan M.; Estelle, Mark; Owen, Markus R.; Vissenberg, Kris; Hodgman, T. Charlie; Pridmore, Tony P.; King, John R.; Vernoux, Teva; Bennett, Malcolm J.

2012-01-01

Gravity profoundly influences plant growth and development. Plants respond to changes in orientation by using gravitropic responses to modify their growth. Cholodny and Went hypothesized over 80 years ago that plants bend in response to a gravity stimulus by generating a lateral gradient of a growth regulator at an organ's apex, later found to be auxin. Auxin regulates root growth by targeting Aux/IAA repressor proteins for degradation. We used an Aux/IAA-based reporter, domain II (DII)-VENUS, in conjunction with a mathematical model to quantify auxin redistribution following a gravity stimulus. Our multidisciplinary approach revealed that auxin is rapidly redistributed to the lower side of the root within minutes of a 90° gravity stimulus. Unexpectedly, auxin asymmetry was rapidly lost as bending root tips reached an angle of 40° to the horizontal. We hypothesize roots use a “tipping point” mechanism that operates to reverse the asymmetric auxin flow at the midpoint of root bending. These mechanistic insights illustrate the scientific value of developing quantitative reporters such as DII-VENUS in conjunction with parameterized mathematical models to provide high-resolution kinetics of hormone redistribution. PMID:22393022

Root gravitropism is regulated by a transient lateral auxin gradient controlled by a tipping-point mechanism.

PubMed

Band, Leah R; Wells, Darren M; Larrieu, Antoine; Sun, Jianyong; Middleton, Alistair M; French, Andrew P; Brunoud, Géraldine; Sato, Ethel Mendocilla; Wilson, Michael H; Péret, Benjamin; Oliva, Marina; Swarup, Ranjan; Sairanen, Ilkka; Parry, Geraint; Ljung, Karin; Beeckman, Tom; Garibaldi, Jonathan M; Estelle, Mark; Owen, Markus R; Vissenberg, Kris; Hodgman, T Charlie; Pridmore, Tony P; King, John R; Vernoux, Teva; Bennett, Malcolm J

2012-03-20

Gravity profoundly influences plant growth and development. Plants respond to changes in orientation by using gravitropic responses to modify their growth. Cholodny and Went hypothesized over 80 years ago that plants bend in response to a gravity stimulus by generating a lateral gradient of a growth regulator at an organ's apex, later found to be auxin. Auxin regulates root growth by targeting Aux/IAA repressor proteins for degradation. We used an Aux/IAA-based reporter, domain II (DII)-VENUS, in conjunction with a mathematical model to quantify auxin redistribution following a gravity stimulus. Our multidisciplinary approach revealed that auxin is rapidly redistributed to the lower side of the root within minutes of a 90° gravity stimulus. Unexpectedly, auxin asymmetry was rapidly lost as bending root tips reached an angle of 40° to the horizontal. We hypothesize roots use a "tipping point" mechanism that operates to reverse the asymmetric auxin flow at the midpoint of root bending. These mechanistic insights illustrate the scientific value of developing quantitative reporters such as DII-VENUS in conjunction with parameterized mathematical models to provide high-resolution kinetics of hormone redistribution.

Analysis of growth patterns during gravitropic curvature in roots of Zea mays by use of a computer-based video digitizer

NASA Technical Reports Server (NTRS)

Nelson, A. J.; Evans, M. L.

1986-01-01

A computer-based video digitizer system is described which allows automated tracking of markers placed on a plant surface. The system uses customized software to calculate relative growth rates at selected positions along the plant surface and to determine rates of gravitropic curvature based on the changing pattern of distribution of the surface markers. The system was used to study the time course of gravitropic curvature and changes in relative growth rate along the upper and lower surface of horizontally-oriented roots of maize (Zea mays L.). The growing region of the root was found to extend from about 1 mm behind the tip to approximately 6 mm behind the tip. In vertically-oriented roots the relative growth rate was maximal at about 2.5 mm behind the tip and declined smoothly on either side of the maximum. Curvature was initiated approximately 30 min after horizontal orientation with maximal (50 degrees) curvature being attained in 3 h. Analysis of surface extension patterns during the response indicated that curvature results from a reduction in growth rate along both the upper and lower surfaces with stronger reduction along the lower surface.

Local flow measurements at the inlet spike tip of a Mach 3 supersonic cruise airplane

NASA Technical Reports Server (NTRS)

Johnson, H. J.; Montoya, E. J.

1973-01-01

The flow field at the left inlet spike tip of a YF-12A airplane was examined using at 26 deg included angle conical flow sensor to obtain measurements at free-stream Mach numbers from 1.6 to 3.0. Local flow angularity, Mach number, impact pressure, and mass flow were determined and compared with free-stream values. Local flow changes occurred at the same time as free-stream changes. The local flow usually approached the spike centerline from the upper outboard side because of spike cant and toe-in. Free-stream Mach number influenced the local flow angularity; as Mach number increased above 2.2, local angle of attack increased and local sideslip angle decreased. Local Mach number was generally 3 percent less than free-stream Mach number. Impact-pressure ratio and mass flow ratio increased as free-stream Mach number increased above 2.2, indicating a beneficial forebody compression effect. No degradation of the spike tip instrumentation was observed after more than 40 flights in the high-speed thermal environment encountered by the airplane. The sensor is rugged, simple, and sensitive to small flow changes. It can provide accurate imputs necessary to control an inlet.

The effects of free stream turbulence on the flow field through a compressor cascade

NASA Astrophysics Data System (ADS)

Muthanna Kolera, Chittiappa

The flow through a compressor cascade with tip leakage has been studied experimentally. The cascade of GE rotor B section blades had an inlet angle of 65.1°, a stagger angle of 56.9°, and a solidity of 1.08. The final turning angle of the cascade was 11.8°. This compressor configuration was representative of the core compressor of an aircraft engine. The cascade was operated with a tip gap of 1.65%, and operated at a Reynolds number based on the chord length (0.254 m) of 388,000. Measurements were made at 8 axial locations to reveal the structure of the flow as it evolved through the cascade. Measurements were also made to reveal the effects of grid generated turbulence on this flow. The data set is unique in that not only does it give a comparison of elevated free stream turbulence effects, but also documents the developing flow through the blade row of a compressor cascade with tip leakage. Measurements were made at a total of 8 locations 0.8, 0.23 axial chords upstream and 0, 0.27, 0.48, 0.77, 0.98, and 1.26 axial chords downstream of the leading edge of the blade row for both inflow turbulence cases. The measurements revealed the formation and development of the tip leakage vortex within the passage. The tip leakage vortex becomes apparent at approximately X/ca = 0.27 and dominated much of the endwall flow. The tip leakage vortex is characterized by high streamwise velocity deficits, high vorticity and high turbulence kinetic energy levels. The result showed that between 0.77 and 0.98 axial chords downstream of the leading edge, the vortex structure and behavior changes. The effects of grid generated turbulence were also documented. The results revealed significant effects on the flow field. The results showed a 4% decrease in the blade loading and a 20% reduction in the vorticity levels within tip leakage vortex. There was also a shift in the vortex path, showing a shift close to the suction side with grid generated turbulence, indicating the strength of the vortex was decreased. Circulation calculations showed this reduction, and also indicated that the tip leakage vortex increased in size by about 30%. The results revealed that overall, the turbulence kinetic energy levels in the tip leakage vortex were increased, with the most drastic change occurring at X/ca = 0.77.

Subdigital setae of chameleon feet: friction-enhancing microstructures for a wide range of substrate roughness.

PubMed

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N

2014-06-27

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion.

Modified tube gastropexy using a mushroom-tipped silicone catheter for management of gastric dilatation-volvulus in dogs.

PubMed

Belch, A; Rubinos, C; Barnes, D C; Nelissen, P

2017-02-01

To report the short- and long-term complications and clinical outcomes of a cohort of dogs managed for gastric dilatation-volvulus using a modified right-sided tube gastropexy technique. Retrospective case series. Of 31 dogs treated, 29 (93·5%) had an excellent short-term outcome, and gastric dilatation-volvulus did not recur in any dog. Twenty-six dogs (84%) were initially fed via the gastrostomy tube postoperatively; three (9·7%) suffered a major complication including septic peritonitis (n=1), and premature tube removal (n=2). Fourteen dogs (45·1%) had minor complications including mild, self-limiting discharge from the stoma site in 13. Modified tube gastropexy using a mushroom-tipped silicone catheter is an effective and safe surgical method for the management of gastric dilatation-volvulus. The gastrostomy tube allowed early enteral feeding and easy administration of medications, including gastroprotectants. © 2017 British Small Animal Veterinary Association.

Design of an Optically Controlled MR-Compatible Active Needle

PubMed Central

Ryu, Seok Chang; Quek, Zhan Fan; Koh, Je-Sung; Renaud, Pierre; Black, Richard J.; Moslehi, Behzad; Daniel, Bruce L.; Cho, Kyu-Jin; Cutkosky, Mark R.

2015-01-01

An active needle is proposed for the development of magnetic resonance imaging (MRI)-guided percutaneous procedures. The needle uses a low-transition-temperature shape memory alloy (LT SMA) wire actuator to produce bending in the distal section of the needle. Actuation is achieved with internal optical heating using laser light transported via optical fibers and side coupled to the LT SMA. A prototype, with a size equivalent to a standard 16-gauge biopsy needle, exhibits significant bending, with a tip deflection of more than 14° in air and 5° in hard tissue. A single-ended optical sensor with a gold-coated tip is developed to measure the curvature independently of temperature. The experimental results in tissue phantoms show that human tissue causes fast heat dissipation from the wire actuator; however, the active needle can compensate for typical targeting errors during prostate biopsy. PMID:26512231

Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness

NASA Astrophysics Data System (ADS)

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N.

2014-06-01

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion.

Negative gravitropism in Chara protonemata: a model integrating the opposite gravitropic responses of protonemata and rhizoids.

PubMed

Hodick, D

1994-11-01

The unicellular protonema of Chara fragilis Desv. was investigated in order to establish a reaction chain for negative gravitropism in tip-growing cells. The time course of gravitropic bending after stimulation at angles of 45 degrees or 90 degrees showed three distinct phases of graviresponse. During the first hour after onset of stimulation a strong upward shift of the tip took place. This initial response was followed by an interval of almost straight growth. Complete reorientation was achieved in a third phase with very low bending rates. Gravitropic reorientation could be completely abolished by basipetal centrifugation of the cells, which lastingly removed conspicuous dark organelles from the protonema tip, thus identifying them as statoliths. Within minutes after onset of gravistimulation most or all statoliths were transported acropetally from their resting position 20-100 micrometers from the cell apex to the lower side of the apical dome. This transport is actin-dependent since it could be inhibited with cytochalasin B. Within minutes after arrival of the statoliths, the apical dome flattened on its lower side and bulged on the upper one. After this massive initial response the statoliths remained firmly sedimented, but the distance between this sedimented complex and the cell vertex increased from 7 micrometers to 22 micrometers during the first hour of stimulation and bending rates sharply declined. From this it is concluded that only statoliths inside the apical dome convey information about the spatial orientation of the cell in the gravitropic reaction chain. After inversion of the protonema the statoliths transiently arranged into a disk-shaped complex about 8 micrometers above the vertex. When this statolith complex tilted towards one side of the apical dome, growth was shifted in the opposite direction and bending started. It is argued that the statoliths intruding into the apical dome may displace a growth-organizing structure from its symmetrical position in the apex and may thus cause bending by bulging. In the positively gravitropic Chara rhizoids only a more stable anchorage of the growth-organizing structure is required. As a consequence, sedimented statoliths cannot dislocate this structure from the vertex. Instead they obstruct a symmetrical distribution of cell-wall-forming vesicles around the structure and thus cause bending by bowing.

Push Tester For Laminated Films

NASA Technical Reports Server (NTRS)

Sugimura, Russell S.

1991-01-01

Small instrument used to measure brittleness of polymer film adhesively bonded to hard substrate. Penlike instrument has microball tip. Small pointer in slot on side of instrument used to calibrate and indicate spring force applied by point. Microball dents only small area of specimen. Such measurements used to measure rates of embrittlement in environmental tests of candidate laminated-film covers for photovoltaic modules. Not limited to transparent films; also used on opaque laminated films on back panels of photovoltaic modules.

Resonance localization and poloidal electric field due to cyclo- tron wave heating in tokamak plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, J.Y.; Chan, V.S.; Harvey, R.W.

1984-08-06

The perpendicular heating in cyclotron waves tends to pile up the resonant particles toward the low magnetic field side with their banana tips localized to the resonant surface. A poloidal electric field with an E x B drift comparable to the ion vertical drift in a toroidal magnetic field may result. With the assumption of anomalous electron and neoclassical ion transport, density variations due to wave heating are discussed.

Re-design and fabrication of titanium multi-wall Thermal Protection System (TPS) test panels

NASA Technical Reports Server (NTRS)

Blair, W.; Meaney, J. E., Jr.; Rosenthal, H. A.

1984-01-01

The Titanium Multi-wall Thermal Protection System (TIPS) panel was re-designed to incorporate Ti-6-2-4-2 outer sheets for the hot surface, ninety degree side closures for ease of construction and through panel fastness for ease of panel removal. Thermal and structural tests were performed to verify the design. Twenty-five panels were fabricated and delivered to NASA for evaluation at Langley Research Center and Johnson Space Center.

Multifunctional Catheters Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

PubMed Central

Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Nikoozadeh, Amin; Oralkan, Omer; Khuri-Yakub, Pierre T.; Sahn, David J.

2015-01-01

A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters’ ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools. PMID:18986948

Multifunctional catheters combining intracardiac ultrasound imaging and electrophysiology sensing.

PubMed

Stephens, D N; Cannata, J; Liu, Ruibin; Zhao, Jian Zhong; Shung, K K; Nguyen, Hien; Chia, R; Dentinger, A; Wildes, D; Thomenius, K E; Mahajan, A; Shivkumar, K; Kim, Kang; O'Donnell, M; Nikoozadeh, A; Oralkan, O; Khuri-Yakub, P T; Sahn, D J

2008-07-01

A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters' ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools.

A remarkably easy knot-tying technique for single-incision laparoscopic surgery with the SILS port for gynecologic diseases.

PubMed

Endo, Toshiaki; Nagasawa, Kunihiko; Umemura, Kota; Baba, Tsuyoshi; Henmi, Hirofumi; Saito, Tsuyoshi

2011-01-01

Single-incision laparoscopic surgery (SILS) has been quickly accepted, especially for women, because the cosmetic benefits may be greater than with ordinary laparoscopic surgery. In gynecologic disease, SILS is appropriate for diagnostic laparoscopy, oophorectomy, and salpingectomy, among other conditions. In addition, the knot-tying process for intracorporeal suturing during SILS is a major rate-limiting step and a key determinant of the popularity of SILS. Although a roticulator instrument is useful for creating the needed operative angle, knot tying is still believed to be difficult. We have devised a remarkably simple knot-tying technique that can be applied during SILS with a SILS Port with a Roticulator and a straight-type needle driver. We determined that, after transfixing the needle, the long tail of the thread should be grasped at around 90 degrees relative to the long axis of tip of the Roticulator, which is articulated at 80 degrees. This automatically forms an ideal C-loop because of gravitation. The needle attached to the long tail should face the distal side from the tip of Roticulator (from the surgeon's perspective). The apex of the C-loop is then toward the proximal side from the tip of the Roticulator (from the perspective of the surgeon). This thread position is important during the knot-tying process. The upper arm of the C-loop should then be entwined by applying a series of axial spinning movements to the rod of the needle driver. At this time, the jaws of the needle driver should be kept open so the thread does not slip off of the rod. The benefit of this technique is that it does not require any special skills; any surgeon able to perform intracorporeal suturing should also be able to easily tie knots during SILS. Copyright © 2011 AAGL. Published by Elsevier Inc. All rights reserved.

Generation of dendrite fragments and their transport from within the mushy zone

NASA Astrophysics Data System (ADS)

Liu, Shan

Five steps have been identified for the grain structure evolution of a casting by an intrinsic mechanism: (i) fragmentation of dendrites in the mushy region; (ii) transport of these dendrite fragments from within this region; (iii) their survival in the bulk liquid; (iv) growth of the survivors; and (v) blockage of the columnar crystal growth front and formation of the equiaxed grains in a casting. Of these, the first two steps remain unclear and are explored in this study. It is found that deceleration of the growth interface leads to fragmentation of side arms from primary stems. This process can be characterized by the Fragmentation Percentage which is related to the magnitude and range of the deceleration, time, and the alloy composition. With decelerations, though temperature gradient at the interface does not change, the dendrite array exhibits important microstructural variations: the dendrite, tip restabilizes rather rapidly (<10 min) and correlates well with the instantaneous tip velocity; and the primary arm spacing restabilization takes ˜5 times longer than the tip readjustment. The difference between the rates of restabilization of the tip radius and primary arm spacing causes slight solute enrichment in the interdendritic region, resulting in side arm detachment. Through a comparative study with the steady state growth process, the magnitude of this solute enrichment is estimated. Further analysis for the dissolution kinetics shows that the excessive solute can only cause a partial dissolution at the neck of a side arm, but this is sufficient to upset the curvature balance between the different sections of a dendritic structure and the continual dissolution at the neck is subsequently driven by the curvature difference until a side arm is detached from the primary stalk. The solidification interface of most castings generally proceeds in a decelerated manner; therefore dendrite fragments already exist in the mushy region. These dendrite fragments can become the nuclei for the central equiaxed zone of a casting or ingot if they are transported out of the mushy zone and into the bulk liquid. The transport may be carried out by natural convection, with channel/plume flow as the most effective carrier; plume velocity and channel diameter are critical for the escape of the dendrite fragments. The selection criteria for them are investigated herein. A new experimental technique of constrained plume promotion has been devised to study the fluid flow behavior. With the simultaneous measurements of the interface advancing velocities, plume flow velocity, composition and temperature of both the plume and the bulk liquid (therefore the buoyancy), the overall flow behavior is quantified and the permeability of the dendrite mushy region is obtained. A model is established to describe natural plume flow and determine the factors for channel size/plume velocity selection. With the results of the constrained case, it is found that the size of a channel is determined by the ratio of the pressure effecting the entrainment in the mush and the pressure necessary for the vertical plume flow, while the absolute value of the pressure controls the plume velocity. Estimates agree well with previous experimental observations. With the number of fragments generated by deceleration and that transported by the entrainment flow, an estimate is made of how many fragments are convected out from the mushy region; this agrees with experimental observations reasonably well.

KSC-04PD-0890

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. A roseate spoonbill takes flight from a lake north of Kennedy Space Center. Spoonbills are so named because of the broad spatulate tip on its long straight bill. They obtain food by sweeping their bills from side to side and scooping up whatever they encounter. The Center shares a boundary north, south and west with the 92,000-acre Merritt Island National Wildlife Refuge, which is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

KSC-04PD-0891

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Roseate spoonbills and white ibis ((long, curved bill) gather in a lake north of Kennedy Space Center. Spoonbills are so named because of the broad spatulate tip on its long straight bill. They obtain food by sweeping their bills from side to side and scooping up whatever they encounter. The Center shares a boundary north, south and west with the 92,000-acre Merritt Island National Wildlife Refuge, which is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

Advanced Energy Conversion Concept for Beamed-Energy Propulsion.

DTIC Science & Technology

1987-08-21

pulsed simultaneously at 40 HL. the thruster will operate almost iMen&1 within the infra - sonIc regime. c) Asymmetric thrust considerations During low...LSD WAVES) - / TIME I-*- INFRA - SONIC I LEVITATIUN FREQUENCY Firm U-27 .?AmpUtude-laimpd macro-pulam .5 " I A. SIDE VIEW CUNICAL TIP ,?I , i...s equal local sta ic), and the sonic velocity. Since cool air can rush in only at the speed of sound, one would want to minimize the expanded plasma

Glass Transition Temperature Measurement for Undercured Cyanate Ester Networks: Challenges, Tips, and Tricks (Briefing Charts)

DTIC Science & Technology

2014-01-29

DISTRIBUTION A: Approved for public release; distribution is unlimited. Thermosetting Polymers Have a TG Envelope – Not Just a TG 4 • The glass transition...glass transition temperature of a thermosetting polymer can vary over a wide range of temperatures depending on how the polymer is processed • A... thermosetting polymer with only one kind of network formation and negligible side reactions, the conversion may be determined at every point in the scan. • By

Make your small practice thrive. Physicians moving from big practices to small must know the business side of medicine.

PubMed

Cowan, D

2001-01-01

Trying to gain a measure of control over their working lives, some physicians are abandoning large group practices for smaller groups. Large groups enjoy whole teams of people performing vital business tasks. Small practices rely on one or two key physicians and managers to tackle everything from customer service to marketing, medical records to human resources. Learn valuable tips for thriving in a small environment and using that extra control to achieve job satisfaction.

Molecular and Electronic Structure of Thin Films of Protoporphyrin(IX)Fe(III)C1

DTIC Science & Technology

1991-11-10

Union Carbide). Electrical contact to the back side of the HOPG sample was made with a copper wire and conductive epoxy (Epo-tek H20E, Epoxy Technology...analysis of the contrast in STM images of copper phthalocyanine [641 and by Zheng and Tsong in their analysis of resonant tunneling via tip-localized...Electroanal. Chem. 1980, 110, 369. 71. Makinen, M.W.; Churg A.K. Iron Porphyri ns-P art One; Lever, A.B.P.; Gray, H.B., Eds.; Physical Bioinorganic

STS-59 crewmembers in training for onboard Earth observations

NASA Technical Reports Server (NTRS)

1993-01-01

The six astronauts in training for the STS-59 mission are shown onboard Earth observations tips by Justin Wilkinson (standing, foreground) of the Space Shuttle Earth Observations Project (SSEOP) group. Astronaut Sidney M. Gutierrez, mission commander, is at center on the left side of the table. Others, left to right, are Astronauts Kevin P. Chilton, pilot; Jerome (Jay) Apt and Michael R.U. (Rich) Clifford, both mission specialists; Linda M. Godwin, payload commander; and Thomas D. Jones, mission specialist.

Crystal growth and fluid mechanics problems in directional solidification

NASA Technical Reports Server (NTRS)

Tanveer, Saleh; Baker, Gregory R.; Foster, Michael R.

1994-01-01

Broadly speaking, our efforts have been concentrated in two aspects of directional solidification: (A) a more complete theoretical understanding of convection effects in a Bridgman apparatus; and (B) a clear understanding of scalings of various features of dendritic crystal growth in the sensitive limit of small capillary effects. For studies that fall within class A, the principal objectives are as follows: (A1) Derive analytical formulas for segregation, interfacial shape and fluid velocities in mathematically amenable asymptotic limits. (A2) Numerically verify and extend asymptotic results to other ranges of parameter space with a view to a broader physical understanding of the general trends. With respect to studies that fall within class B, the principal objectives include answering the following questions about dendritic crystal growth: (B1) Are there unsteady dendrite solutions in 2-D to the completely nonlinear time evolving equations in the small surface tension limit with only a locally steady tip region with well defined tip radius and velocity? Is anisotropy in surface tension necessary for the existence of such solutions as it is for a true steady state needle crystal? How does the size of such a local region depend on capillary effects, anisotropy and undercooling? (B2) How do the different control parameters affect the nonlinear amplification of tip noise and dendritic side branch coarsening?

Nature of inclined growth in thin-layer electrodeposition under uniform magnetic fields.

PubMed

Soba, Alejandro; González, Graciela; Calivar, Lucas; Marshall, Guillermo

2012-11-01

Electrochemical deposition (ECD) in thin cells in a vertical position relative to gravity, subject to an external uniform magnetic field, yields a growth pattern formation with dense branched morphology with branches tilted in the direction of the magnetic force. We study the nature of the inclined growth through experiments and theory. Experiments in ECD, in the absence of magnetic forces, reveal that a branch grows by allowing fluid to penetrate its tip and to be ejected from the sides through a pair of symmetric vortices attached to the tip. The upper vortices zone defines an arch separating an inner zone ion depleted and an outer zone in a funnel-like form with a concentrated solution through which metal ions are carried into the tip. When a magnetic field is turned on, vortex symmetry is broken, one vortex becoming weaker than the other, inducing an inclination of the funnel. Consequently, particles entering the funnel give rise to branch growth tilted in the same direction. Theory predicts, in the absence of a magnetic force, funnel symmetry induced through symmetric vortices driven by electric and gravitational forces; when the magnetic force is on, it is composed with the pair of clockwise and counterclockwise vortices, reducing or amplifying one or the other. In turn, funnel tilting modifies particle trajectories, thus, growth orientation.

Frequency-dependent photothermal measurement of transverse thermal diffusivity of organic semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brill, J. W.; Shahi, Maryam; Yao, Y.

2015-12-21

We have used a photothermal technique, in which chopped light heats the front surface of a small (∼1 mm{sup 2}) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid-nitrogen-cooled infrared detector. In our system, the sample is placed directly in front of the detector within its dewar. Because the detector is also sensitive to some of the incident light, which leaks around or through the sample, measurements are made for the detector signal that is in quadrature with the chopped light. Results are presented for layered crystals of semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pn)more » and for papers of cellulose nanofibrils coated with semiconducting poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (NFC-PEDOT). For NFC-PEDOT, we have found that the transverse diffusivity, smaller than the in-plane value, varies inversely with thickness, suggesting that texturing of the papers varies with thickness. For TIPS-pn, we have found that the interlayer diffusivity is an order of magnitude larger than the in-plane value, consistent with previous estimates, suggesting that low-frequency optical phonons, presumably associated with librations in the TIPS side groups, carry most of the heat.« less

Surface-restrained growth of vertically aligned carbon nanotube arrays with excellent thermal transport performance.

PubMed

Ping, Linquan; Hou, Peng-Xiang; Liu, Chang; Li, Jincheng; Zhao, Yang; Zhang, Feng; Ma, Chaoqun; Tai, Kaiping; Cong, Hongtao; Cheng, Hui-Ming

2017-06-22

A vertically aligned carbon nanotube (VACNT) array is a promising candidate for a high-performance thermal interface material in high-power microprocessors due to its excellent thermal transport property. However, its rough and entangled free tips always cause poor interfacial contact, which results in serious contact resistance dominating the total thermal resistance. Here, we employed a thin carbon cover to restrain the disorderly growth of the free tips of a VACNT array. As a result, all the free tips are seamlessly connected by this thin carbon cover and the top surface of the array is smoothed. This unique structure guarantees the participation of all the carbon nanotubes in the array in the heat transport. Consequently the VACNT array grown on a Cu substrate shows a record low thermal resistance of 0.8 mm 2 K W -1 including the two-sided contact resistances, which is 4 times lower than the best result previously reported. Remarkably, the VACNT array can be easily peeled away from the Cu substrate and act as a thermal pad with excellent flexibility, adhesive ability and heat transport capability. As a result the CNT array with a thin carbon cover shows great potential for use as a high-performance flexible thermal interface material.

Comparison of the ultrastructure of conventionally fixed and high pressure frozen/freeze substituted root tips of Nicotiana and Arabidopsis

NASA Technical Reports Server (NTRS)

Kiss, J. Z.; Giddings, T. H. Jr; Staehelin, L. A.; Sack, F. D.

1990-01-01

To circumvent the limitations of chemical fixation (CF) and to gain more reliable structural information about higher plant tissues, we have cryofixed root tips of Nicotiana and Arabidopsis by high pressure freezing (HPF). Whereas other freezing techniques preserve tissue to a relatively shallow depth, HPF in conjunction with freeze substitution (FS) resulted in excellent preservation of entire root tips. Compared to CF, in tissue prepared by HPF/FS: (1) the plasmalemma and all internal membranes were much smoother and often coated on the cytoplasmic side by a thin layer of stained material, (2) the plasmalemma was appressed to the cell wall, (3) organelle profiles were rounder, (4) the cytoplasmic, mitochondrial, and amyloplast matrices were denser, (5) vacuoles contained electron dense material, (6) microtubules appeared to be more numerous and straighter, with crossbridges observed between them, (7) cisternae of endoplasmic reticulum (ER) were wider and filled with material, (8) Golgi intercisternal elements were more clearly resolved and were observed between both Golgi vesicles and cisternae, and (9) larger vesicles were associated with Golgi stacks. This study demonstrates that HPF/FS can be used to successfully preserve the ultrastructure of relatively large plant tissues without the use of intracellular cryoprotectants.

Hydrotropism and its interaction with gravitropism in maize roots

NASA Technical Reports Server (NTRS)

Takahashi, H.; Scott, T. K.

1991-01-01

We have partially characterized root hydrotropism and its interaction with gravitropism in maize (Zea mays L.). Roots of Golden Cross Bantam 70, which require light for orthogravitropism, showed positive hydrotropism; bending upward when placed horizontally below a hydrostimulant (moist cheesecloth) in 85% relative humidity (RH) and in total darkness. However, the light-exposed roots of Golden Cross Bantam 70 or roots of a normal maize cultivar, Burpee Snow Cross, showed positive gravitropism under the same conditions; bending downward when placed horizontally below the hydrostimulant in 85% RH. Light-exposed roots of Golden Cross Bantam 70 placed at 70 degrees below the horizontal plane responded positively hydrotropically, but gravitropism overcame the hydrotropism when the roots were placed at 45 degrees below the horizontal. Roots placed vertically with the tip down in 85% RH bent to the side toward the hydrostimulant in both cultivars, and light conditions did not affect the response. Such vertical roots did not respond when the humidity was maintained near saturation. These results suggest that hydrotropic and gravitropic responses interact with one another depending on the intensity of one or both factors. Removal of the approximately 1.5 millimeter root tip blocked both hydrotropic and gravitropic responses in the two cultivars. However, removal of visible root tip mucilage did not affect hydrotropism or gravitropism in either cultivar.

Experimental investigation of a new device to control the asymmetric flowfield on forebodies at large angles of attack

NASA Technical Reports Server (NTRS)

Moskovitz, Cary A.; Hall, Robert M.; Dejarnette, F. R.

1990-01-01

An exploratory experimental investigation of a new device to control the asymmetric flowfield on forebodies at large angles of attack has been conducted. The device is a rotatable forebody tip, which varies in cross section from circular at its base to elliptic at its tip. The device itself extends over a small portion of the aircraft or missile forebody. The device provides two important improvements. First, it replaced the normally random behavior of the nose side force as a function of nose tip orientation with a predictable and generally sinusoidal distribution and, second, the device showed promise for use as part of a vehicle control system, to be deflected in a prescribed manner to provide additional directional control for the vehicle. The device was tested on a cone/cylinder model having a 10 deg semiapex angle and on a 3.0 caliber tangent ogive model, each with a base diameter of 3.5 in, for angles of attack from 30 to 60 deg. Data were taken from 3 circumferential rows of pressure taps on each model at a Reynolds number of 84,000 based on cylinder diameter and by a helium-bubble flow visualization technique at a Reynolds number of 24,000.

Flow visualization for investigating stator losses in a multistage axial compressor

NASA Astrophysics Data System (ADS)

Smith, Natalie R.; Key, Nicole L.

2015-05-01

The methodology and implementation of a powder-paint-based flow visualization technique along with the illuminated flow physics are presented in detail for application in a three-stage axial compressor. While flow visualization often accompanies detailed studies, the turbomachinery literature lacks a comprehensive study which both utilizes flow visualization to interrupt the flow field and explains the intricacies of execution. Lessons learned for obtaining high-quality images of surface flow patterns are discussed in this study. Fluorescent paint is used to provide clear, high-contrast pictures of the recirculation regions on shrouded vane rows. An edge-finding image processing procedure is implemented to provide a quantitative measure of vane-to-vane variability in flow separation, which is approximately 7 % of the suction surface length for Stator 1. Results include images of vane suction side corner separations from all three stages at three loading conditions. Additionally, streakline patterns obtained experimentally are compared with those calculated from computational models. Flow physics associated with vane clocking and increased rotor tip clearance and their implications to stator loss are also investigated with this flow visualization technique. With increased rotor tip clearance, the vane surface flow patterns show a shift to larger separations and more radial flow at the tip. Finally, the effects of instrumentation on the flow field are highlighted.

Propeller tip and hub vortex dynamics in the interaction with a rudder

NASA Astrophysics Data System (ADS)

Felli, Mario; Falchi, Massimo

2011-11-01

In the present paper, the interaction mechanisms of the vortices shed by a single-screw propeller with a rudder installed in its wake are addressed; in particular, following the works by Felli et al. (Exp Fluids 6(1):1-11, 2006a, Exp Fluids 46(1):147-1641, 2009a, Proceedings of the 8th international symposium on particle image velocimetry: Piv09, Melbourne, 2009b), the attention is focused on the analysis of the evolution, instability, breakdown and recovering mechanisms of the propeller tip and hub vortices during the interaction with the rudder. To investigate these mechanisms in detail, a wide experimental activity consisting in time-resolved visualizations, velocity measurements by particle image velocimetry (PIV) and laser Doppler velocimetry (LDV) along horizontal chordwise, vertical chordwise and transversal sections of the wake have been performed in the Cavitation Tunnel of the Italian Navy. Collected data allows to investigate the major flow features that distinguish the flow field around a rudder operating in the wake of a propeller, as, for example, the spiral breakdown of the vortex filaments, the rejoining mechanism of the tip vortices behind the rudder and the mechanisms governing the different spanwise misalignment of the vortex filaments in the pressure and suction sides of the appendage.

Heat Transfer in a Complex Trailing Edge Passage for a High Pressure Turbine Blade - Part 1: Experimental Measurements. Part 1; Experimental Measurements

NASA Technical Reports Server (NTRS)

Bunker, Ronald S.; Wetzel, Todd G.; Rigby, David L.; Reddy, D. R. (Technical Monitor)

2000-01-01

A combined experimental and computational study has been performed to investigate the detailed heat transfer coefficient distributions within a complex blade trailing edge passage. The experimental measurements are made using a steady liquid crystal thermography technique applied to one major side of the passage. The geometry of the trailing edge passage is that of a two-pass serpentine circuit with a sharp 180-degree turning region at the tip. The upflow channel is split by interrupted ribs into two major subchannels, one of which is turbulated. This channel has an average aspect ratio of roughly 14:1. The spanwise extent of the channel geometry includes both area convergence from root to tip, as well as taper towards the trailing edge apex. The average section Reynolds numbers tested in this upflow channel range from 55,000 to 98,000. The tip section contains a turning vane near the extreme comer. The downflow channel has an aspect ratio of about 5:1, and also includes convergence and taper. Turbulators of varying sizes are included in this channel also. Both detailed heat transfer and pressure distribution measurements are presented. The pressure measurements are incorporated into a flow network model illustrating the major loss contributors.

Aerodynamics of yacht sails: viscous flow features and surface pressure distributions

NASA Astrophysics Data System (ADS)

Viola, Ignazio Maria

2014-11-01

The present paper presents the first Detached Eddy Simulation (DES) on a yacht sails. Wind tunnel experiments on a 1:15th model-scale sailing yacht with an asymmetric spinnaker (fore sail) and a mainsails (aft sail) were modelled using several time and grid resolutions. Also the Reynolds-average Navier-Stokes (RANS) equations were solved for comparison with DES. The computed forces and surface pressure distributions were compared with those measured with both flexible and rigid sails in the wind tunnel and good agreement was found. For the first time it was possible to recognise the coherent and steady nature of the leading edge vortex that develops on the leeward side of the asymmetric spinnaker and which significantly contributes to the overall drive force. The leading edge vortex increases in diameter from the foot to the head of the sail, where it becomes the tip vortex and convects downstream in the direction of the far field velocity. The tip vortex from the head of the mainsail rolls around the one of the spinnaker. The spanwise twist of the spinnaker leads to a mid-span helicoidal vortex, which has never been reported by previous authors, with an horizontal axis and rotating in the same direction of the tip vortex.

Size-dependent longitudinal plasmon resonance wavelength and extraordinary scattering properties of Au nanobipyramids.

PubMed

Wang, Wenhao; Yu, Peng; Zhong, Zhiqin; Tong, Xin; Liu, Tianji; Li, Yanbo; Ashalley, Eric; Chen, Huanyang; Wu, Jiang; Wang, Zhiming

2018-08-31

Au nanobipyramids (NBPs) with sharp tips and narrow plasmon linewidths are ideal candidates for plasmonic applications. In this paper, we investigated the influencing factors of longitudinal plasmon resonance wavelength (LPRW) and scattering properties of single Au NBP by simulation. Compared with the volume, we establish the aspect ratio (length/width) as the dominant factor that affects the LPRW of Au NBPs. Plasmonic nanoparticles have been widely used for light-trapping enhancement in photovoltaics. To give a profound understanding of the superior light harvesting properties of Au NBPs, the near-field localization effect and far-field scattering mechanism of Au NBPs were investigated. Under the light injection at LPRW, the tip area shows near-field enhancement and the maximum scattering intensity appears on the side area of the waist owing to the remarkable optical absorption near the tips. Additionally, we confirm the fraction of light scattered into the substrate and angular distribution of the light scattered by the Au NBPs. The fraction of light scattered into the substrate reaches up to 97% from 400-1100 nm and preserves a broadband spectrum. This suggests that the NBP has a predominant forward scattering and reduced backward scattering. The excellent plasmonic scattering properties of Au NBPs are promising in photovoltaic devices and photothermal therapy.

A cell-body groove housing the new flagellum tip suggests an adaptation of cellular morphogenesis for parasitism in the bloodstream form of Trypanosoma brucei.

PubMed

Hughes, Louise; Towers, Katie; Starborg, Tobias; Gull, Keith; Vaughan, Sue

2013-12-15

Flagella are highly conserved organelles present in a wide variety of species. In Trypanosoma brucei the single flagellum is necessary for morphogenesis, cell motility and pathogenesis, and is attached along the cell body. A new flagellum is formed alongside the old during the cell division cycle. In the (insect) procyclic form, the flagella connector (FC) attaches the tip of the new flagellum to the side of the old flagellum, ensuring faithful replication of cell architecture. The FC is not present in the bloodstream form of the parasite. We show here, using new imaging techniques including serial block-face scanning electron microscopy (SBF-SEM), that the distal tip of the new flagellum in the bloodstream form is embedded within an invagination in the cell body plasma membrane, named the groove. We suggest that the groove has a similar function to the flagella connector. The groove is a mobile junction located alongside the microtubule quartet (MtQ) and occurred within a gap in the subpellicular microtubule corset, causing significant modification of microtubules during elongation of the new flagellum. It appears likely that this novel form of morphogenetic structure has evolved to withstand the hostile immune response in the mammalian blood.

A pharmacokinetic-pharmacodynamic model for intrathecal baclofen in patients with severe spasticity.

PubMed

Heetla, H W; Proost, J H; Molmans, B H; Staal, M J; van Laar, T

2016-01-01

Intrathecal baclofen (ITB) has proven to be an effective and safe treatment for severe spasticity. However, although ITB is used extensively, clinical decisions are based on very scarce pharmacokinetic-pharmacodynamic (PKPD) data. The aim of this study was to measure baclofen CSF concentrations and clinical effects after administration of various ITB boluses in patients with spasticity and to create a PKPD model for ITB. Twelve patients with severe spasticity received four different bolus doses of ITB (0, 25, 50, 75 μg and an optional dose of 100 μg), administered via a catheter with the tip at thoracic level (Th) 10. After each bolus, 10 CSF samples were taken at fixed time intervals, using a catheter with the tip located at Th12. Clinical effect was assessed by measuring spasticity with the Modified Ashworth Scale (MAS). These data were used to develop a PKPD model. All patients achieved an adequate spasmolytic effect with ITB doses varying from 50 to 100 μg. No serious side effects were observed. CSF baclofen concentrations, as well as the clinical effects, correlated significantly with ITB doses. The PK model predicted a steep spinal concentration gradient of ITB along the spinal axis. The clinical effect could be predicted using a delayed-effect model. ITB is an effective and safe therapy with, however, a steep concentration gradient along the spinal axis. This means that the administered baclofen is staying mainly around the catheter tip, which stresses the importance to position the ITB catheter tip closely to the targeted spinal level. © 2015 The British Pharmacological Society.

Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells

PubMed Central

Barton, Deborah A.; Law, Andrew M.K.; Overall, Robyn L.

2015-01-01

Lobe development in the epidermal pavement cells of Arabidopsis thaliana cotyledons and leaves is thought to take place via tip-like growth on the concave side of lobes driven by localized concentrations of actin filaments and associated proteins, with a predicted role for cortical microtubules in establishing the direction of restricted growth at the convex side. We used homologous landmarks fixed to the outer walls of pavement cells and thin-plate spline analysis to demonstrate that lobes form by differential growth of both the anticlinal and periclinal walls. Most lobes formed within the first 24 h of the cotyledons unfurling, during the period of rapid cell expansion. Cortical microtubules adjacent to the periclinal wall were persistently enriched at the convex side of lobes during development where growth was anisotropic and were less concentrated or absent at the concave side where growth was promoted. Alternating microtubule-enriched and microtubule-free zones at the periclinal wall in neighboring cells predicted sites of new lobes. There was no particular arrangement of cortical actin filaments that could predict where lobes would form. However, drug studies demonstrate that both filamentous actin and microtubules are required for lobe formation. PMID:26296967

"The little squealer" or "the virtual guardian angel"? Young drivers' and their parents' perspective on using a driver monitoring technology and its implications for parent-young driver communication.

PubMed

Guttman, Nurit; Gesser-Edelsburg, Anat

2011-02-01

In-vehicle driving monitoring technologies have the potential to enable young drivers to learn from self-assessment. However, their use is largely dependent on parental involvement. A total of 79 interviews were conducted with young drivers and parents regarding this technology and its use. Most had the experience of having an in-vehicle data recorder installed in the vehicle driven by the young drivers. Parents and the young drivers expressed both appreciation as well as reservations about its potential as a means to enhance the driving safety of young drivers. A surprising finding was that some parents did not check the feedback and said they relied on the young driver to do so. Main concerns related to privacy, parent-young driver relationship, self-esteem and confidence, constructive use of the feedback data, and the limitations of the documentation that can be done by the technology. Providing parents and young drivers with a support system and tools to discuss and utilize the feedback are underscored. Challenges include addressing the invasion of young drivers' privacy and gender differences, and using the monitoring-capacity of the technology to enhance safe driving practices. Implications for programs to enhance communication and a dialogical approach between parents and young drivers are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Doppler-guided retrograde catheterization system

NASA Astrophysics Data System (ADS)

Frazin, Leon J.; Vonesh, Michael J.; Chandran, Krishnan B.; Khasho, Fouad; Lanza, George M.; Talano, James V.; McPherson, David D.

1991-05-01

The purpose of this study was to investigate a Doppler guided catheterization system as an adjunctive or alternative methodology to overcome the disadvantages of left heart catheterization and angiography. These disadvantages include the biological effects of radiation and the toxic and volume effects of iodine contrast. Doppler retrograde guidance uses a 20 MHz circular pulsed Doppler crystal incorporated into the tip of a triple lumen multipurpose catheter and is advanced retrogradely using the directional flow information provided by the Doppler waveform. The velocity detection limits are either 1 m/second or 4 m/second depending upon the instrumentation. In a physiologic flow model of the human aortic arch, multiple data points revealed a positive wave form when flow was traveling toward the catheter tip indicating proper alignment for retrograde advancement. There was a negative wave form when flow was traveling away from the catheter tip if the catheter was in a branch or bent upon itself indicating improper catheter tip position for retrograde advancement. In a series of six dogs, the catheter was able to be accurately advanced from the femoral artery to the left ventricular chamber under Doppler signal guidance without the use of x-ray. The potential applications of a Doppler guided retrograde catheterization system include decreasing time requirements and allowing safer catheter guidance in patients with atherosclerotic vascular disease and suspected aortic dissection. The Doppler system may allow left ventricular pressure monitoring in the intensive care unit without the need for x-ray and it may allow left sided contrast echocardiography. With pulse velocity detection limits of 4 m/second, this system may allow catheter direction and passage into the aortic root and left ventricle in patients with aortic stenosis. A modification of the Doppler catheter may include transponder technology which would allow precise catheter tip localization once the catheter tip is placed in the aortic root. Such technology may conceivably assist in allowing selective coronary catheterization. These studies have demonstrated that Doppler guided retrograde catheterization provides an accurate method to catheterization the aortic root and left ventricular chamber without x-ray. In humans, it may prove useful in a variety of settings including the development of invasive ultrasonic diagnostic and therapeutic technology.

Off-fault tip splay networks: a genetic and generic property of faults indicative of their long-term propagation, and a major component of off-fault damage

NASA Astrophysics Data System (ADS)

Perrin, C.; Manighetti, I.; Gaudemer, Y.

2015-12-01

Faults grow over the long-term by accumulating displacement and lengthening, i.e., propagating laterally. We use fault maps and fault propagation evidences available in literature to examine geometrical relations between parent faults and off-fault splays. The population includes 47 worldwide crustal faults with lengths from millimeters to thousands of kilometers and of different slip modes. We show that fault splays form adjacent to any propagating fault tip, whereas they are absent at non-propagating fault ends. Independent of parent fault length, slip mode, context, etc, tip splay networks have a similar fan shape widening in direction of long-term propagation, a similar relative length and width (~30 and ~10 % of parent fault length, respectively), and a similar range of mean angles to parent fault (10-20°). Tip splays more commonly develop on one side only of the parent fault. We infer that tip splay networks are a genetic and a generic property of faults indicative of their long-term propagation. We suggest that they represent the most recent damage off-the parent fault, formed during the most recent phase of fault lengthening. The scaling relation between parent fault length and width of tip splay network implies that damage zones enlarge as parent fault length increases. Elastic properties of host rocks might thus be modified at large distances away from a fault, up to 10% of its length. During an earthquake, a significant fraction of coseismic slip and stress is dissipated into the permanent damage zone that surrounds the causative fault. We infer that coseismic dissipation might occur away from a rupture zone as far as a distance of 10% of the length of its causative fault. Coseismic deformations and stress transfers might thus be significant in broad regions about principal rupture traces. This work has been published in Comptes Rendus Geoscience under doi:10.1016/j.crte.2015.05.002 (http://www.sciencedirect.com/science/article/pii/S1631071315000528).

Analysis of Statoliths Displacement in Chara Rhizoids for Validating the Microgravity-Simulation Quality of Clinorotation Modes

NASA Astrophysics Data System (ADS)

Krause, Lars; Braun, Markus; Hauslage, Jens; Hemmersbach, Ruth

2018-05-01

In single-celled rhizoids of the green algae Chara, positively gravitropic growth is governed by statoliths kept in a dynamically stable position 10-25 μ m above the cell tip by a complex interaction of gravity and actomyosin forces. Any deviation of the tube-like cells from the tip-downward orientation causes statoliths to sediment onto the gravisensitive subapical cell flank which initiates a gravitropic curvature response. Microgravity experiments have shown that abolishing the net tip-directed gravity force results in an actomyosin-mediated axial displacement of statoliths away from the cell tip. The present study was performed to critically assess the quality of microgravity simulation provided by different operational modes of a Random Positioning Machine (RPM) running with one axis (2D mode) or two axes (3D mode) and different rotational speeds (2D), speed ranges and directions (3D). The effects of 2D and 3D rotation were compared with data from experiments in real microgravity conditions (MAXUS sounding rocket missions). Rotational speeds in the range of 60-85 rpm in 2D and 3D modes resulted in a similar kinetics of statolith displacement as compared to real microgravity data, while slower clinorotation (2-11 rpm) caused a reduced axial displacement and a more dispersed arrangement of statoliths closer to the cell tip. Increasing the complexity of rotation by adding a second rotation axis in case of 3D clinorotation did not increase the quality of microgravity simulation, however, increased side effects such as the level of vibrations resulting in a more dispersed arrangement of statoliths. In conclusion, fast 2D clinorotation provides the most appropriate microgravity simulation for investigating the graviperception mechanism in Chara rhizoids, whereas slower clinorotation speeds and rotating samples around two axes do not improve the quality of microgravity simulation.

Analysis of Statoliths Displacement in Chara Rhizoids for Validating the Microgravity-Simulation Quality of Clinorotation Modes

NASA Astrophysics Data System (ADS)

Krause, Lars; Braun, Markus; Hauslage, Jens; Hemmersbach, Ruth

2018-01-01

In single-celled rhizoids of the green algae Chara, positively gravitropic growth is governed by statoliths kept in a dynamically stable position 10-25 μ m above the cell tip by a complex interaction of gravity and actomyosin forces. Any deviation of the tube-like cells from the tip-downward orientation causes statoliths to sediment onto the gravisensitive subapical cell flank which initiates a gravitropic curvature response. Microgravity experiments have shown that abolishing the net tip-directed gravity force results in an actomyosin-mediated axial displacement of statoliths away from the cell tip. The present study was performed to critically assess the quality of microgravity simulation provided by different operational modes of a Random Positioning Machine (RPM) running with one axis (2D mode) or two axes (3D mode) and different rotational speeds (2D), speed ranges and directions (3D). The effects of 2D and 3D rotation were compared with data from experiments in real microgravity conditions (MAXUS sounding rocket missions). Rotational speeds in the range of 60-85 rpm in 2D and 3D modes resulted in a similar kinetics of statolith displacement as compared to real microgravity data, while slower clinorotation (2-11 rpm) caused a reduced axial displacement and a more dispersed arrangement of statoliths closer to the cell tip. Increasing the complexity of rotation by adding a second rotation axis in case of 3D clinorotation did not increase the quality of microgravity simulation, however, increased side effects such as the level of vibrations resulting in a more dispersed arrangement of statoliths. In conclusion, fast 2D clinorotation provides the most appropriate microgravity simulation for investigating the graviperception mechanism in Chara rhizoids, whereas slower clinorotation speeds and rotating samples around two axes do not improve the quality of microgravity simulation.

Hormonal regulation of gravitropic bending

NASA Astrophysics Data System (ADS)

Hu, X.; Cui, D.; Xu, X.; Hu, L.; Cai, W.

Gravitropic bending is an important subject in the research of plant Recent data support the basics of the Cholodny-Went hypothesis indicating that differential growth in gravitropism is due to redistribution of auxin to the lower sides of gravistimulated roots but little is known regarding the molecular details of such effects So we carried a series of work surround the signals induced by auxin end center We found the endogenous signaling molecules nitric oxide NO and cGMP mediate responses to gravistimulation in primary roots of soybean Glycine max Horizontal orientation of soybean roots caused the accumulation of both NO and cGMP in the primary root tip Fluorescence confocal microcopy revealed that the accumulation of NO was asymmetric with NO concentrating in the lower side of the root Auxin induced NO accumulation in root protoplasts and asymmetric NO accumulation in root tips Gravistimulation NO and auxin also induced the accumulation of cGMP a response inhibited by removal of NO or by inhibitors of guanylyl cyclase compounds that also reduced gravitropic bending Asymmetric NO accumulation and gravitropic bending were both inhibited by an auxin transport inhibitor and the inhibition of bending was overcome by treatment with NO or 8-bromo-cGMP a cell-permeable analog of cGMP These data indicate that auxin-induced NO and cGMP mediate gravitropic curvature in soybean roots From Hu et al Plant Physiol 2005 137 663-670 The asymmetric distribution of auxin plays a fundamental role in plant gravitropic bending

Forty-five-degree or higher insertion angles are required to penetrate the opposite cortex in bicortical applications of Kirschner wires: an in vitro study on sheep bones.

PubMed

Colak, Mehmet; Gurer, Burak; Sungur, Mehmet Ali; Eskandari, Metin Manouchehr

2012-04-01

Slippage of the wires over the opposite cortex from the endosteal side is frequent and can lead to insufficient stability. This in vitro biomechanical study was planned to investigate the angle of wire insertion that leads to trans cortex perforation. Long bones of sheep were cut longitudinally into two pieces and half bones were stabilised on a frame. Three orthopaedic surgeons performed the experiment using ten wires of four different diameters at two different drilling speeds. Each wire was introduced from the endosteal side at angles starting at 30° in 5° increments until perforation. When perforation was achieved, the angle was recorded. To determinate the critical angle of perforation, receiver operating characteristic (ROC) curve analyses was performed. Two-way factorial analysis of variance (ANOVA) and Kruskal-Wallis tests were used for statistical comparisons. Kirschner-wire insertion angles of ≥ 45° provided perforation with a percentage of 83.9 %. Wire diameter, drilling speed and surgeon variables had no effect on perforation angles (p > 0.05). If preoperative evaluation of fractures to be fixed by K wires reveals the need for oblique wire insertion angle < 45°, a standard trocar-tip K wire application would lead to slippage of the wire tip on the endosteal surface of the opposite cortex. According to this study, the operative plan should be changed if such obliquity of the K wire is mandatory during bicortical applications.

Description of a new species of Microhyla from Bali, Indonesia (Amphibia, Anura).

PubMed

Matsui, Masafumi; Hamidy, Amir; Eto, Koshiro

2013-01-01

We describe a microhylid frog from Bali, Indonesia as a new species, Microhyla orientalis sp. nov. It belongs to the M. achatina group and is close to M. mantheyi, M. malang, and M. borneensis. It is distinguished from its congeners by a combination of the following characters: small size (adult males about 16-17 mm in SVL); a faint vertebral stripe present; a black lateral stripe from behind eye to half length of trunk; snout rounded in profile; eyelid without supraciliary spines; first finger less than one-fifth of third; tips of three outer fingers weakly dilated, forming weak disks, dorsally with median longitudinal groove; outer palmar tubercle single; tibiotarsal articulation reaching up to center of eye; tips of toes distinctly dilated into disks, dorsally with median longitudinal groove; inner and outer metatarsal tubercles present; four or more phalanges on inner and outer sides of fourth toe, and three phalanges on inner side of fifth toe free of web; and tail of larva with a black marking at middle. The male advertisement call of the new species consists of a series of notes each lasts for 0.01-0.08 s and composed of 3-5 pulses with a dominant frequency of 3.2-3.6 kHz. Uncorrected sequence divergences between M. orientalis and all homologous 16S rRNA sequences available were > 6.6%. At present, the new species is known from rice fields between 435-815 m elevation in Wongaya Gede and Batukaru.

Removably attachable snubber assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Jr., Nicholas F.; Wiebe, David J.

A removably attachable snubber assembly for turbine blades includes a turbine blade airfoil including a trailing edge and a leading edge joined by a pressure side and a suction side to provide an outer surface extending in a radial direction to a tip. At least one snubber attachment platform is integrally formed onto the outer surface of the turbine blade airfoil. The at least one snubber attachment platform includes an interlocking mechanism. A snubber is removably attachable to the at least one snubber attachment platform, the snubber including a first end, a second end, a trailing edge, a leading edge,more » a snubber length, and a snubber width. The snubber also includes a removable attachment mechanism on at least one of the first end and the second end that connects with the interlocking mechanism on the at least one snubber attachment platform.« less

KSC-04PD-0888

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Roseate spoonbills wade in the shallow water (foreground) while white pelicans and herons gather in deeper water (background) on a lake north of Kennedy Space Center. The spoonbills are so named because of the broad spatulate tip on its long straight bill. They obtain food by sweeping their bills from side to side and scooping up whatever they encounter. The Center shares a boundary north, south and west with the 92,000-acre Merritt Island National Wildlife Refuge, which is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

Variable-focus side-firing endoscopic device

NASA Astrophysics Data System (ADS)

Lemberg, Vladimir G.; Black, Michael

1996-05-01

Conventional side-firing fiber technology exhibits performance limitations and utilizes expensive single-use only devices which often require multiple fibers for laser prostatectomy. Another limitation of existing side-firing fiber technology is its inability to focus the beam to create incisions for urologic applications such as laser TURP (transurethral resectional prostatectomy), tumor necrosis, lithotripsy, genital warts, and photodynamic therapy. Newly introduced variable-focus side-firing endoscopic device utilizes either one or two lenses and a mirror, onto a single cylinder of molded glass. The laser beam exits the optical fiber, passes through the lens, strikes the cylindrical mirror, and traverses the cylindrical surface. Depending on the design, the laser beam is reflected at the angles ranging from 30 degrees to 120 degrees out of the cylindrical lens. A second lens can be formed onto the side of the cylindrical surface at the beam's exit point. Another advantage of the innovative side-firing device is its capability to provide versatile matching to multiple laser wavelengths from 360 nm to 2.5 microns, and achieve power densities great enough to perform vaporization, incision and coagulation of tissue. Precise focusing of the laser beam results in reduced tissue necrosis of surrounding the treatment area as well as in decreased laser radiation back-scattering. Surgeons can very the focus by adjusting the distance from the tip to the target area. The variable focus side-firing device provides a focused beam at the range of 1.0 to 1.5 mm, for incision. Outside this range, it produces a defocused beam for coagulation.

Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness

PubMed Central

Spinner, Marlene; Westhoff, Guido; Gorb, Stanislav N.

2014-01-01

Hairy adhesive systems of microscopic setae with triangular flattened tips have evolved convergently in spiders, insects and arboreal lizards. The ventral sides of the feet and tails in chameleons are also covered with setae. However, chameleon setae feature strongly elongated narrow spatulae or fibrous tips. The friction enhancing function of these microstructures has so far only been demonstrated in contact with glass spheres. In the present study, the frictional properties of subdigital setae of Chamaeleo calyptratus were measured under normal forces in the physical range on plane substrates having different roughness. We showed that chameleon setae maximize friction on a wide range of substrate roughness. The highest friction was measured on asperities of 1 μm. However, our observations of the climbing ability of Ch. calyptratus on rods of different diameters revealed that also claws and grasping feet are additionally responsible for the force generation on various substrates during locomotion. PMID:24970387

Analysis of the curve of Spee and the curve of Wilson in adult Indian population: A three-dimensional measurement study.

PubMed

Surendran, Sowmya Velekkatt; Hussain, Sharmila; Bhoominthan, S; Nayar, Sanjna; Jayesh, Ragavendra

2016-01-01

When reconstructing the occlusal curvatures dentists often use a 4-inch radii arc as a rough standard based on Monson spherical theory. The use of an identical radius for the curve of Spee for all patients may not be appropriate because each patient is individually different. The validity of application of this theory in the Indian population and the present study has been undertaken. This study is an attempt to evaluate the curve of Spee and curve of Wilson in young Indian population using three dimensional analysis. This study compared the radius and the depth of right and left, maxillary and mandibular curves of Spee and the radius of maxillary and mandibular curves of Wilson in males and females. The cusp tips of canines, buccal cusp tips of premolars and molars and palatal/lingual cusp tips of second molars of 60 maxillary and 60 mandibular casts were obtained. Three-dimensional (x, y, z) coordinates of the cusp tips of the molars, premolars, and canines of the right and left sides of the maxilla and mandible were obtained with three dimensional coordinate measuring machine. The radius and the depth of right and left, maxillary and mandibular curves of Spee and the radius of maxillary and mandibular curves of Wilson were measured by means of computer software Metrologic-XG. Pearson's correlation test and Independent t-test were used to test the statistical significance (α=.05). The values of curve of Spee and curve of Wilson in Indian population obtained from this study were higher than the 4 inch (100 mm) radius proposed by Monson. These findings suggest ethnic differences in the radius of curve of Spee and curve of Wilson.

Wind Tunnel Measurements of the Wake of a Full-Scale UH-60A Rotor in Forward Flight

NASA Technical Reports Server (NTRS)

Wadcock, Alan J.; Yamauchi, Gloria K.; Schairer, Edward T.

2013-01-01

A full-scale UH-60A rotor was tested in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel in May 2010. The test was designed to acquire a suite of measurements to validate state-of-the-art modeling tools. Measurements include blade airloads (from a single pressure-instrumented blade), blade structural loads (strain gages), rotor performance (rotor balance and torque measurements), blade deformation (stereo-photogrammetry), and rotor wake measurements (Particle Image Velocimetry (PIV) and Retro-reflective Backward Oriented Schlieren (RBOS)). During the test, PIV measurements of flow field velocities were acquired in a stationary cross-flow plane located on the advancing side of the rotor disk at approximately 90 deg rotor azimuth. At each test condition, blade position relative to the measurement plane was varied. The region of interest (ROI) was 4-ft high by 14-ft wide and covered the outer half of the blade radius. Although PIV measurements were acquired in only one plane, much information can be gleaned by studying the rotor wake trajectory in this plane, especially when such measurements are augmented by blade airloads and RBOS data. This paper will provide a comparison between PIV and RBOS measurements of tip vortex position and vortex filament orientation for multiple rotor test conditions. Blade displacement measurements over the complete rotor disk will also be presented documenting blade-to-blade differences in tip-path-plane and providing additional information for correlation with PIV and RBOS measurements of tip vortex location. In addition, PIV measurements of tip vortex core diameter and strength will be presented. Vortex strength will be compared with measurements of maximum bound circulation on the rotor blade determined from pressure distributions obtained from 235 pressure sensors distributed over 9 radial stations.

Cavitation noise studies on marine propellers

NASA Astrophysics Data System (ADS)

Sharma, S. D.; Mani, K.; Arakeri, V. H.

1990-04-01

Experimental observations are described of cavitation inception and noise from five model propellers, three basic and two modified, tested in the open jet section of the Indian Institute of Science high-speed water tunnel facility. Extensive experiments on the three basic propellers of different design, which included visualization of cavitation and measurements of noise, showed that the dominant type of cavitation was in the form of tip vortex cavitation, accompanied by leading edge suction side sheet cavitation in its close vicinity, and the resultant noise depended on parameters such as the advance coefficient, the cavitation number, and the propeller geometry. Of these, advance coefficient was found to have the maximum influence not only on cavitation noise but also on the inception of cavitation. Noise levels and frequencies of spectra obtained from all the three basic propellers at conditions near inception and different advance coefficient values, when plotted in the normalized form as suggested by Blake, resulted in a universal spectrum which would be useful for predicting cavitation noise at prototype scales when a limited extent of cavitation is expected in the same form as observed on the present models. In an attempt to delay the onset of tip vortex cavitation, the blades of two of the three basic propellers were modified by drilling small holes in the tip and leading edge areas. Studies on the modified propellers showed that the effectiveness of the blade modification was apparently stronger at low advance coefficient values and depended on the blade sectional profile. Measurements of cavitation noise indicated that the modification also improved the acoustic performance of the propellers as it resulted in a complete attenuation of the low-frequency spectral peaks, which were prominent with the basic propellers. In addition to the above studies, which were conducted under uniform flow conditions, one of the basic propellers was tested in the simulated wake of a typical single screw ship. The wake was simulated by using a wire screen technique. Observations of cavitation and measurement of noise clearly showed that the presence of the wake had a strong influence on the propeller cavitation and noise performance. Cavitation was found to be of the cloud type, which generated very intense noise compared to that generated by tip vortex cavitation along with leading edge suction side sheet cavitation in the uniform flow conditions. The noise spectra obtained with wake simulation also are presented in a normalized form to be of general utility.

Advective pathways near the tip of the Antarctic Peninsula: Trends, variability and ecosystem implications

NASA Astrophysics Data System (ADS)

Renner, Angelika H. H.; Thorpe, Sally E.; Heywood, Karen J.; Murphy, Eugene J.; Watkins, Jon L.; Meredith, Michael P.

2012-05-01

Pathways and rates of ocean flow near the Antarctic Peninsula are strongly affected by frontal features, forcings from the atmosphere and the cryosphere. In the surface mixed layer, the currents advect material from the northwestern Weddell Sea on the eastern side of the Peninsula around the tip of the Peninsula to its western side and into the Scotia Sea, connecting populations of Antarctic krill (Euphausia superba) and supporting the ecosystem of the region. Modelling of subsurface drifters using a particle tracking algorithm forced by the velocity fields of a coupled sea ice-ocean model (ORCA025-LIM2) allows analysis of the seasonal and interannual variability of drifter pathways over 43 years. The results show robust and persistent connections from the Weddell Sea both to the west into the Bellingshausen Sea and across the Scotia Sea towards South Georgia, reproducing well the observations. The fate of the drifters is sensitive to their deployment location, in addition to other factors. From the shelf of the eastern Antarctic Peninsula, the majority enter the Bransfield Strait and subsequently the Bellingshausen Sea. When originating further offshore over the deeper Weddell Sea, drifters are more likely to cross the South Scotia Ridge and reach South Georgia. However, the wind field east and southeast of Elephant Island, close to the tip of the Peninsula, is crucial for the drifter trajectories and is highly influenced by the Southern Annular Mode (SAM). Increased advection and short travel times to South Georgia, and reduced advection to the western Antarctic Peninsula can be linked to strong westerlies, a signature of the positive phase of the SAM. The converse is true for the negative phase. Strong westerlies and shifts of ocean fronts near the tip of the Peninsula that are potentially associated with both the SAM and the El Niño-Southern Oscillation restrict the connection from the Weddell Sea to the west, and drifters then predominantly follow the open paths to South Georgia and the east. Over the 43-year time series, the number of drifters advected into the Bellingshausen Sea decreases significantly by 23% and the travel time to South Georgia shortens significantly by 19% which corresponds to 56 days. We propose that these trends are linked, at least in part, to the increasingly positive trend in the SAM and, as such, this suggests an additional anthropogenic source of change to the regional ecosystem.

Non-Newtonian Hele-Shaw Flow and the Saffman-Taylor Instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondic, L.; Shelley, M.J.; Palffy-Muhoray, P.

We explore the Saffman-Taylor instability of a gas bubble expanding into a shear thinning liquid in a radial Hele-Shaw cell. Using Darcy{close_quote}s law generalized for non-Newtonian fluids, we perform simulations of the full dynamical problem. The simulations show that shear thinning significantly influences the developing interfacial patterns. Shear thinning can suppress tip splitting, and produce fingers which oscillate during growth and shed side branches. Emergent length scales show reasonable agreement with a general linear stability analysis. {copyright} {ital 1998} {ital The American Physical Society}

Calcium- and potassium-permeable plasma membrane transporters are activated by copper in Arabidopsis root tips: linking copper transport with cytosolic hydroxyl radical production.

PubMed

Rodrigo-Moreno, Ana; Andrés-Colás, Nuria; Poschenrieder, Charlotte; Gunsé, Benet; Peñarrubia, Lola; Shabala, Sergey

2013-04-01

Transition metals such as copper can interact with ascorbate or hydrogen peroxide to form highly reactive hydroxyl radicals (OH(•) ), with numerous implications to membrane transport activity and cell metabolism. So far, such interaction was described for extracellular (apoplastic) space but not cytosol. Here, a range of advanced electrophysiological and imaging techniques were applied to Arabidopsis thaliana plants differing in their copper-transport activity: Col-0, high-affinity copper transporter COPT1-overexpressing (C1(OE) ) seedlings, and T-DNA COPT1 insertion mutant (copt1). Low Cu concentrations (10 µm) stimulated a dose-dependent Gd(3+) and verapamil sensitive net Ca(2+) influx in the root apex but not in mature zone. C1(OE) also showed a fivefold higher Cu-induced K(+) efflux at the root tip level compared with Col-0, and a reduction in basal peroxide accumulation at the root tip after copper exposure. Copper caused membrane disruptions of the root apex in C1(OE) seedlings but not in copt1 plants; this damage was prevented by pretreatment with Gd(3+) . Our results suggest that copper transport into cytosol in root apex results in hydroxyl radical generation at the cytosolic side, with a consequent regulation of plasma membrane OH(•) -sensitive Ca(2+) and K(+) transport systems. © 2012 Blackwell Publishing Ltd.

Control of submersible vortex flows

NASA Technical Reports Server (NTRS)

Bushnell, D. M.; Donaldson, C. D.

1990-01-01

Vortex flows produced by submersibles typically unfavorably influence key figures of merit such as acoustic and nonacoustic stealth, control effectiveness/maneuverability, and propulsor efficiency/body drag. Sources of such organized, primarily longitudinal, vorticity include the basic body (nose and sides) and appendages (both base/intersection and tip regions) such as the fairwater, dive planes, rear control surfaces, and propulsor stators/tips. Two fundamentally different vortex control approaches are available: (1) deintensification of the amplitude and/or organization of the vortex during its initiation process; and (2) downstream vortex disablement. Vortex control techniques applicable to the initiation region (deintensification approach) include transverse pressure gradient minimization via altered body cross section, appendage dillets, fillets, and sweep, and various appendage tip and spanload treatment along with the use of active controls to minimize control surface size and motions. Vortex disablement can be accomplished either via use of control vortices (which can also be used to steer the vortices off-board), direct unwinding, inducement of vortex bursting, or segmentation/tailoring for enhanced dissipation. Submersible-applicable vortex control technology is also included derived from various aeronautical applications such as mitigation of the wing wake vortex hazard and flight aircraft maneuverability at high angle of attack as well as the status of vortex effects upon, and mitigation of, nonlinear control forces on submersibles. Specific suggestions for submersible-applicable vortex control techniques are presented.

Regulation of Dental Enamel Shape and Hardness

PubMed Central

Simmer, J.P.; Papagerakis, P.; Smith, C.E.; Fisher, D.C.; Rountrey, A.N.; Zheng, L.; Hu, J.C.-C.

2010-01-01

Epithelial-mesenchymal interactions guide tooth development through its early stages and establish the morphology of the dentin surface upon which enamel will be deposited. Starting with the onset of amelogenesis beneath the future cusp tips, the shape of the enamel layer covering the crown is determined by five growth parameters: the (1) appositional growth rate, (2) duration of appositional growth (at the cusp tip), (3) ameloblast extension rate, (4) duration of ameloblast extension, and (5) spreading rate of appositional termination. Appositional growth occurs at a mineralization front along the ameloblast distal membrane in which amorphous calcium phosphate (ACP) ribbons form and lengthen. The ACP ribbons convert into hydroxyapatite crystallites as the ribbons elongate. Appositional growth involves a secretory cycle that is reflected in a series of incremental lines. A potentially important function of enamel proteins is to ensure alignment of successive mineral increments on the tips of enamel ribbons deposited in the previous cycle, causing the crystallites to lengthen with each cycle. Enamel hardens in a maturation process that involves mineral deposition onto the sides of existing crystallites until they interlock with adjacent crystallites. Neutralization of acidity generated by hydroxyapatite formation is a key part of the mechanism. Here we review the growth parameters that determine the shape of the enamel crown as well as the mechanisms of enamel appositional growth and maturation. PMID:20675598

Monobloc Reconstruction of Dome, Medial Crura, and Columella with Gamma-Shaped Costal Cartilage Graft

PubMed Central

Bilgili, Ahmet Mert; Güven, Erdem

2017-01-01

Summary: In severe nasal deformities, the original cartilages are removed, or they become unusable because of previous operations. Costal cartilage (CC) is one of the most important tools for the replacement of deficient nasal osteocartilaginous framework. In 4 secondary and 1 tertiary rhinoplasty cases with severe deformities of medial and lateral crura of the lower lateral cartilages, we have prepared a long strut graft from a CC and then split the graft tip 5–6 mm vertically into 2 equal halves to create a gamma (ϒ)-shaped strut graft. We have sutured the base of this graft to the nasal spine and/or the bases of the medial crural remnants. Then, we have prepared lateral crural grafts and secured the grafts over lateral crural remnants. Then we curved the split tip winglets of the ϒ-shaped strut graft to both sides and sutured them to lateral crural grafts in order to create a new dome. Splitting of the CC strut graft reduces the need for extensive suturing at the tip, obtains smoother contours and ensures graft economy, and provides an original and stable dome shape. The bending capacity of the CC is limited in middle-aged patients. Costal allografts from a young cadaver can be a good alternative. ϒ-shaped costal crural graft is useful for medial crural and domal monobloc reconstruction in secondary and tertiary cases. PMID:29632798

Regulation of Cell Diameter, For3p Localization, and Cell Symmetry by Fission Yeast Rho-GAP Rga4p

PubMed Central

Das, Maitreyi; Wiley, David J.; Medina, Saskia; Vincent, Helen A.; Larrea, Michelle; Oriolo, Andrea

2007-01-01

Control of cellular dimensions and cell symmetry are critical for development and differentiation. Here we provide evidence that the putative Rho-GAP Rga4p of Schizosaccharomyces pombe controls cellular dimensions. rga4Δ cells are wider in diameter and shorter in length, whereas Rga4p overexpression leads to reduced diameter of the growing cell tip. Consistent with a negative role in cell growth control, Rga4p protein localizes to the cell sides in a “corset” pattern, and to the nongrowing cell tips. Additionally, rga4Δ cells show an altered growth pattern similar to that observed in mutants of the formin homology protein For3p. Consistent with these observations, Rga4p is required for normal localization of For3p and for normal distribution of the actin cytoskeleton. We show that different domains of the Rga4p protein mediate diverse morphological functions. The C-terminal GAP domain mediates For3p localization to the cell tips and maintains cell diameter. Conversely, overexpression of the N-terminal LIM homology domain of Rga4p promotes actin cable formation in a For3p-dependent manner. Our studies indicate that Rga4p functionally interacts with For3p and has a novel function in the control of cell diameter and cell growth. PMID:17377067

Thermal Analysis by Numerical Methods of Debonding Effects near the Crack Tip under Composite Repairs

NASA Astrophysics Data System (ADS)

Tsamasphyros, G. J.; Kanderakis, G. N.; Marioli-Riga, Z. P.

2003-05-01

Composite patch repair of metallic structures has become a rapidly grown technology in the aerospace field due to the demand for significant increases in the useful life of both military and civilian aircraft. This has led to significant advances overall in the repair technology of cracked metallic structures. Adhesively bonded composite reinforcements offer remarkable advantages such as mechanical efficiency, repair time, cost reduction, high structural integrity, repair inspectability, damage tolerance to further causes of future strains, anticorrosion and antifretting properties. However, because of the different nature and properties of the materials that form a repair (metals, composites, adhesives), side-effects may occur: debonding due to high stress concentration in the vicinity of the crack, thermal residual stresses because of different thermal expansion coefficients of the adherents, etc. In this paper a three-dimensional finite elements analysis of the area around a patch repaired crack of a typical aircraft fuselage is performed, taking into account both the properties and the geometry of the involved materials. Examined in this case are 2024-T3 aluminum alloy as base material, FM-73 as the adhesive system and F4/5521 boron/epoxy prepreg as the patch material. Through the thickness stresses near the crack tip and along the patch edges with and without temperature effects are calculated and debonding near the crack tip is examined. Finally, the calculated results are compared with existing theories.

Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells.

PubMed

Armour, William J; Barton, Deborah A; Law, Andrew M K; Overall, Robyn L

2015-09-01

Lobe development in the epidermal pavement cells of Arabidopsis thaliana cotyledons and leaves is thought to take place via tip-like growth on the concave side of lobes driven by localized concentrations of actin filaments and associated proteins, with a predicted role for cortical microtubules in establishing the direction of restricted growth at the convex side. We used homologous landmarks fixed to the outer walls of pavement cells and thin-plate spline analysis to demonstrate that lobes form by differential growth of both the anticlinal and periclinal walls. Most lobes formed within the first 24 h of the cotyledons unfurling, during the period of rapid cell expansion. Cortical microtubules adjacent to the periclinal wall were persistently enriched at the convex side of lobes during development where growth was anisotropic and were less concentrated or absent at the concave side where growth was promoted. Alternating microtubule-enriched and microtubule-free zones at the periclinal wall in neighboring cells predicted sites of new lobes. There was no particular arrangement of cortical actin filaments that could predict where lobes would form. However, drug studies demonstrate that both filamentous actin and microtubules are required for lobe formation. © 2015 American Society of Plant Biologists. All rights reserved.

The Carnegie Hubble Program: The Distance and Structure of the SMC as Revealed by Mid-Infrared Observations of Cepheids

NASA Technical Reports Server (NTRS)

Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andy; Persson, S. E.; Rich, Jeff; Seibert, Mark; Rigby, Jane R.

2016-01-01

Using Spitzer observations of classical Cepheids we have measured the true average distance modulus of the Small Magellanic Cloud (SMC) to be18.96 +/- 0.01 stat +/- 0.03sys mag (corresponding to 62+/- 0.3kpc), which is 0.48 +/- 0.01 mag more distant than the LMC. This is in agreement with previous results from Cepheid observations, as well as with measurements from other indicators such as RR Lyrae stars and the tip of the red giant branch. Utilizing the properties of the mid-infrared Leavitt Law we measured precise distances to individual Cepheids in the SMC, and have confirmed that the galaxy is tilted and elongated such that its eastern side is up to20 kpc closer than its western side. This is in agreement with the results from red clump stars and dynamical simulations of the Magellanic Clouds and Stream.

A Roseate Spoonbill hunts for food in the water.

NASA Technical Reports Server (NTRS)

1999-01-01

A Roseate Spoonbill sweeps the water for food in the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The brilliant pink bird is named for its straight bill with the broad spatulate tip. Preferring a habitat of mangroves, it is usually found on the coasts of southern Florida and Texas, occasionally in Louisiana., in the West Indies, Mexico and Central and South America. Spoonbills feed on shrimps and fish in shallow waters, sweeping their bills from side to side and scooping up whatever they encounter. The 92,000- acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

Cesium injection system for negative ion duoplasmatrons

DOEpatents

Kobayashi, Maasaki; Prelec, Krsto; Sluyters, Theodorus J

1978-01-01

Longitudinally extending, foraminous cartridge means having a cylindrical side wall forming one flat, circular, tip end surface and an opposite end; an open-ended cavity, and uniformly spaced orifices for venting the cavity through the side wall in the annulus of a plasma ring for uniformly ejecting cesium for coating the flat, circular, surface. To this end, the cavity is filled with a cesium containing substance and attached to a heater in a hollow-discharge duoplasmatron. By coating the flat circular surface with a uniform monolayer of cesium and locating it in an electrical potential well at the end of a hollow-discharge, ion duoplasmatron source of an annular hydrogen plasma ring, the negative hydrogen production from the duoplasmatron is increased. The negative hydrogen is produced on the flat surface of the cartridge and extracted by the electrical potential well along a trajectory coaxial with the axis of the plasma ring.

KSC-04PD-0893

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Roseate spoonbills gather in the shallow water (foreground) of a lake north of Kennedy Space Center. In the background at left are white ibis, identified by their down-curving bills. Spoonbills are so named because of the broad spatulate tip on its long straight bill. They obtain food by sweeping their bills from side to side and scooping up whatever they encounter. The Center shares a boundary north, south and west with the 92,000-acre Merritt Island National Wildlife Refuge, which is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

Histological and morphological observations on tongue of Scincella tsinlingensis (Reptilia, Squamata, Scincidae).

PubMed

Yang, Chun; Wang, Limin

2016-01-01

The histology and morphology characteristics of the tongue in Scincella tsinlingensis were studied by light and electronic microscopy. Under light microscopy, the tongue consists of tip, lingual body and radix in sequence. Numerous lingual papillae widely distribute on the surface of the dorsal and ventral flanks in the tongue, in addition to some regions of the tip. The papillae's surface is covered with the epithelial layer. The lamina propria and dense connective tissue are distinct existing under the epithelial layer. There are many lingual glands spread over the lamina propria. Tongue muscle is developed and composed of distinct intrinsic muscle, hyoglossus and genioglossus. By scanning electron microscopy, at higher magnification, the epithelial cells of the dorsal surface in the divaricate tongue tips show numerous microvilli, micro-ridges and micro-pores. The surface of dorsal side of the papillae in lingual body is covered with abundant of micro-ridges and taste bud lacuna. On the surface of the papillae in radix, micro-facets and micro-ridges are compactly distributed, as well as scattered mucilage-pores. The lingual epithelium is divided into four layers observed by the transmission electron microscope. Cells of basal layer are irregularly elliptical in shape, with sparse organelles in the cytoplasm. The deep intermediate layer is not always distinct. Small numbers of organelles are scattered into the cytoplasm. The cells of the superficial intermediate layer gradually flatten, as do their nuclei. The cytoplasm contains many keratohyalin granules. Cell membranes are formed processes around cells and joined by abundant desmosomes to the cell membranes of adjacent cells. The cells located on the extreme free-surface side of the keratinized layer have fallen off. The basal lamina is intercalated between the basal layer and the lamina propria. The lamina propria of lingual body contains lingual gland. A large part of the cytoplasm is occupied by mucus granules which located in the distal part of the cell. The connective tissue contains myelinated nerve fibers, vessel and muscle cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

A visual stethoscope to detect the position of the tracheal tube.

PubMed

Kato, Hiromi; Suzuki, Akira; Nakajima, Yoshiki; Makino, Hiroshi; Sanjo, Yoshimitsu; Nakai, Takayoshi; Shiraishi, Yoshito; Katoh, Takasumi; Sato, Shigehito

2009-12-01

Advancing a tracheal tube into the bronchus produces unilateral breath sounds. We created a Visual Stethoscope that allows real-time fast Fourier transformation of the sound signal and 3-dimensional (frequency-amplitude-time) color rendering of the results on a personal computer with simultaneous processing of 2 individual sound signals. The aim of this study was to evaluate whether the Visual Stethoscope can detect bronchial intubation in comparison with auscultation. After induction of general anesthesia, the trachea was intubated with a tracheal tube. The distance from the incisors to the carina was measured using a fiberoptic bronchoscope. While the anesthesiologist advanced the tracheal tube from the trachea to the bronchus, another anesthesiologist auscultated breath sounds to detect changes of the breath sounds and/or disappearance of bilateral breath sounds for every 1 cm that the tracheal tube was advanced. Two precordial stethoscopes placed at the left and right sides of the chest were used to record breath sounds simultaneously. Subsequently, at a later date, we randomly entered the recorded breath sounds into the Visual Stethoscope. The same anesthesiologist observed the visualized breath sounds on the personal computer screen processed by the Visual Stethoscope to examine changes of breath sounds and/or disappearance of bilateral breath sound. We compared the decision made based on auscultation with that made based on the results of the visualized breath sounds using the Visual Stethoscope. Thirty patients were enrolled in the study. When irregular breath sounds were auscultated, the tip of the tracheal tube was located at 0.6 +/- 1.2 cm on the bronchial side of the carina. Using the Visual Stethoscope, when there were any changes of the shape of the visualized breath sound, the tube was located at 0.4 +/- 0.8 cm on the tracheal side of the carina (P < 0.01). When unilateral breath sounds were auscultated, the tube was located at 2.6 +/- 1.2 cm on the bronchial side of the carina. The tube was also located at 2.3 +/- 1.0 cm on the bronchial side of the carina when a unilateral shape of visualized breath sounds was obtained using the Visual Stethoscope (not significant). During advancement of the tracheal tube, alterations of the shape of the visualized breath sounds using the Visual Stethoscope appeared before the changes of the breath sounds were detected by auscultation. Bilateral breath sounds disappeared when the tip of the tracheal tube was advanced beyond the carina in both groups.

Simple physics-based analytical formulas for the potentials of mean force of the interaction of amino-acid side chains in water. V. Like-charged side chains.

PubMed

Makowski, Mariusz; Liwo, Adam; Sobolewski, Emil; Scheraga, Harold A

2011-05-19

A new model of side-chain-side-chain interactions for charged side-chains of amino acids, to be used in the UNRES force-field, has been developed, in which a side chain consists of a nonpolar and a charged site. The interaction energy between the nonpolar sites is composed of a Gay-Berne and a cavity term; the interaction energy between the charged sites consists of a Lennard-Jones term, a Coulombic term, a generalized-Born term, and a cavity term, while the interaction energy between the nonpolar and charged sites is composed of a Gay-Berne and a polarization term. We parametrized the energy function for the models of all six pairs of natural like-charged amino-acid side chains, namely propionate-propionate (for the aspartic acid-aspartic acid pair), butyrate-butyrate (for the glutamic acid-glutamic acid pair), propionate-butyrate (for the aspartic acid-glutamic acid pair), pentylamine cation-pentylamine cation (for the lysine-lysine pair), 1-butylguanidine cation-1-butylguanidine cation (for the arginine-arginine pair), and pentylamine cation-1-butylguanidine cation (for the lysine-arginine pair). By using umbrella-sampling molecular dynamics simulations in explicit TIP3P water, we determined the potentials of mean force of the above-mentioned pairs as functions of distance and orientation and fitted analytical expressions to them. The positions and depths of the contact minima and the positions and heights of the desolvation maxima, including their dependence on the orientation of the molecules were well represented by analytical expressions for all systems. The values of the parameters of all the energy components are physically reasonable, which justifies use of such potentials in coarse-grain protein-folding simulations. © 2011 American Chemical Society

[Echo-guided radiofrequency percutaneous ablation of hepatocellular carcinoma in cirrhosis using a cooled needle].

PubMed

Marone, G; Francica, G; D'Angelo, V; Iodice, G; Pastore, P; Altamura, G; Cusati, B; Siani, A

1998-06-01

Radiofrequency hyperthermia using the newly-developed "cooled-tip" needle is one of the latest US-guided percutaneous treatments of hepatocellular carcinoma arising in cirrhosis. The continuous cooling of the needle tip allows tissue heating and necrosis far from the electrode without tissue charring, which was the major drawback of the old monopolar technique. Herein we report our preliminary results on feasibility and effectiveness of the thermoablation of mono- or paucifocal hepatocellular carcinoma with the cooled-tip needle. November, 1996, to January, 1998, we treated thirteen cirrhotic patients (mean age 69.5 yrs, 10 men, 12 HCV-positive; 11 in Child's Class A and 2 in Class B) with 19 hepatocellular carcinoma nodules (mean diameter: 27 mm; range: 10-41 mm; 6 with diameter > 3 cm). None of the patients had portal thrombosis and/or extrahepatic spread. We used a radiofrequency generator (100 W power) connected to an 18 G perfusion electrode needle with an exposed tip of 2-3 cm. The circuit is closed through a dispersive electrode positioned under the patient's thighs. A peristaltic pump infuses a chilled (2-5 degrees C) saline solution to guarantee the continuous cooling of the needle tip. The needle was placed into target lesions under US guidance. The interventional procedure was carried out under general anesthesia using Propofol without intubation. Dynamic CT (more recently with the helical technique) was carried out 15-20 days after thermoablation to assess treatment efficacy. In all, 31 thermal injuries (at 1000-1200 mA for 10-15 minutes) were caused in 21 sessions in the 19 hepatocellular carcinoma nodules (mean: 1.5 lesions per nodule and 1.6 sessions per patient). Complete necrosis as assessed at dynamic CT (no enhancement during the arteriographic phase) was achieved in 16 of 19 nodules (84%). No side-effects occurred. During the follow-up (median: 11 months) no death occurred and five patients had recurrent hepatocellular carcinoma appearing either as single nodule or as multinodular liver involvement. In our experience radiofrequency hyperthermia with the cooled-tip needle permits effective and safe percutaneous ablation of HCC in cirrhosis. In addition, treatment time is short and lesions > 3 cm can be treated. Further experience is needed to better define the role of percutaneous thermoablation in the treatment strategy of hepatocellular carcinoma.

Imaging electron flow from collimating contacts in graphene

NASA Astrophysics Data System (ADS)

Bhandari, S.; Lee, G. H.; Watanabe, K.; Taniguchi, T.; Kim, P.; Westervelt, R. M.

2018-04-01

The ballistic motion of electrons in graphene opens exciting opportunities for electron-optic devices based on collimated electron beams. We form a collimating contact in a hBN-encapsulated graphene hall bar by adding zigzag contacts on either side of an electron emitter that absorb stray electrons; collimation can be turned off by floating the zig-zag contacts. The electron beam is imaged using a liquid-He cooled scanning gate microscope (SGM). The tip deflects electrons as they pass from the collimating contact to a receiving contact on the opposite side of the channel, and an image of electron flow can be made by displaying the change in transmission as the tip is raster scanned across the sample. The angular half width Δθ of the electron beam is found by applying a perpendicular magnetic field B that bends electron paths into cyclotron orbits. The images reveal that the electron flow from the collimating contact drops quickly at B  =  0.05 T when the electron orbits miss the receiving contact. The flow for the non-collimating case persists longer, up to B  =  0.19 T, due to the broader range of entry angles. Ray-tracing simulations agree well with the experimental images. By fitting the fields B at which the magnitude of electron flow drops in the experimental SGM images, we find Δθ  =  9° for electron flow from the collimating contact, compared with Δθ  =  54° for the non-collimating case.

Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

NASA Technical Reports Server (NTRS)

Skoch, G. J.; Prahst, P. S.; Wernet, M. P.; Wood, J. R.; Strazisar, A. J.

1997-01-01

A laser-doppler anemometer was used to obtain flow-field velocity measurements in a 4:1 pressure ratio, 4.54 kg/s (10 lbm/s), centrifugal impeller, with splitter blades and backsweep, which was configured with a vaneless diffuser. Measured through-flow velocities are reported for ten quasi-orthogonal survey planes at locations ranging from 1% to 99% of main blade chord. Measured through-flow velocities are compared to those predicted by a 3-D viscous steady flow analysis (Dawes) code. The measurements show the development and progression through the impeller and vaneless diffuser of a through-flow velocity deficit which results from the tip clearance flow and accumulation of low momentum fluid centrifuged from the blade and hub surfaces. Flow traces from the CFD analysis show the origin of this deficit which begins to grow in the inlet region of the impeller where it is first detected near the suction surface side of the passage. It then moves toward the pressure side of the channel, due to the movement of tip clearance flow across the impeller passage, where it is cut by the splitter blade leading edge. As blade loading increases toward the rear of the channel the deficit region is driven back toward the suction surface by the cross-passage pressure gradient. There is no evidence of a large wake region that might result from flow separation and the impeller efficiency is relatively high. The flow field in this impeller is quite similar to that documented previously by NASA Lewis in a large low-speed backswept impeller.

Applying AFM-based nanofabrication for measuring the thickness of nanopatterns: the role of head groups in the vertical self-assembly of omega-functionalized n-alkanethiols.

PubMed

Kelley, Algernon T; Ngunjiri, Johnpeter N; Serem, Wilson K; Lawrence, Steve O; Yu, Jing-Jiang; Crowe, William E; Garno, Jayne C

2010-03-02

Molecules of n-alkanethiols with methyl head groups typically form well-ordered monolayers during solution self-assembly for a wide range of experimental conditions. However, we have consistently observed that, for either carboxylic acid or thiol-terminated n-alkanethiols, under certain conditions nanografted patterns are generated with a thickness corresponding precisely to a double layer. To investigate the role of head groups for solution self-assembly, designed patterns of omega-functionalized n-alkanethiols were nanografted with systematic changes in concentration. Nanografting is an in situ approach for writing patterns of thiolated molecules on gold surfaces by scanning with an AFM tip under high force, accomplished in dilute solutions of desired ink molecules. As the tip is scanned across the surface of a self-assembled monolayer under force, the matrix molecules are displaced from the surface and are immediately replaced with fresh molecules from solution to generate nanopatterns. In this report, side-by-side comparison of nanografted patterns is achieved for different matrix molecules using AFM images. The chain length and head groups (i.e., carboxyl, hydroxyl, methyl, thiol) were varied for the nanopatterns and matrix monolayers. Interactions such as head-to-head dimerization affect the vertical self-assembly of omega-functionalized n-alkanethiol molecules within nanografted patterns. At certain threshold concentrations, double layers were observed to form when nanografting with head groups of carboxylic acid and dithiols, whereas single layers were generated exclusively for nanografted patterns with methyl and hydroxyl groups, regardless of changes in concentration.

Tilt/Tip/Piston Manipulator with Base-Mounted Actuators

NASA Technical Reports Server (NTRS)

Tahmasebi, Farhad

2006-01-01

A proposed three-degree-of-freedom (tilt/tip/piston) manipulator, suitable for aligning an optical or mechanical component, would offer several advantages over prior such manipulators: Unlike in some other manipulators, no actuator would support the weight of another actuator: All of the actuators would be mounted on a base. Hence, there would be less manipulated weight. The basic geometry of the manipulator would afford mechanical advantage: that is, actuator motions would be larger than the motions they produce in the manipulated object. Mechanical advantage inherently increases the accuracy and resolution of manipulation. Unlike in some other manipulators, it would not be necessary to route power and/or data lines through manipulator joints. The proposed manipulator (see figure) would include three prismatic actuators (T1N1, T2N2, and T3N3) mounted on the base and operating in the same plane. Examples of suitable prismatic actuators include lead-screw mechanisms, linear hydraulic motors, piezoelectric linear drives, inchworm-movement linear stepping motors, and linear flexure drives. The actuators would control the lengths of links R1T1, R2T2, and R3T3. Three spherical joints (P1, P2, and P3) would be located at the corners of an equilateral triangle of side length q on the platform holding the object to be manipulated. Three inextensible limbs (R1P1, R2P2, and R3P3) having length r would connect the spherical joints on the platform to revolute joints (R1, R2, and R3) at the ends of the actuator-controlled links R1T1, R2T2, and R3T3. By varying the lengths of these links, one could control the tilt, tip, and piston coordinates of the platform. Closed-form equations for direct or forward kinematics of the manipulator (given the lengths of the variable links, find the tilt, tip, and piston coordinates) have been derived. The equations of inverse kinematics (find the variable link lengths needed to obtain the desired tilt, tip, and piston coordinates) have also been derived.

The Brassicaceae species Heliophila coronopifolia produces root border-like cells that protect the root tip and secrete defensin peptides.

PubMed

Weiller, Florent; Moore, John P; Young, Philip; Driouich, Azeddine; Vivier, Melané A

2017-03-01

Root border cells and border-like cells (BLCs), the latter originally described in Arabidopsis thaliana , have been described as cells released at the root tips of the species in which they occur. BLCs are thought to provide protection to root meristems similar to classical root border cells. In addition, four defensin peptides (Hc-AFP1-4) have previously been characterized from Heliophila coronopifolia , a South African semi-desert flower, and found to be strongly antifungal. This provided an opportunity to evaluate if the BLCs of H. coronopifolia indeed produce these defensins, which would provide evidence towards a defence role for BLCs. Fluorescence microscopy, using live-cell-imaging technology, was used to characterize the BLCs of H. coronopifolia . Quantitative real-time PCR (qRT-PCR) analysis and immunofluorescence microscopy was used to characterize these defensin peptides. BLCs originated at the root apical meristem and formed a protective sheath at the tip and along the sides as the root elongated in solid medium. BLCs have a cellulose-enriched cell wall, intact nuclei and are embedded in a layer of pectin-rich mucilage. Pectinase treatments led to the dissolution of the sheath and dissociation of the root BLCs. Hc-AFP1-4 genes were all expressed in root tissues, but Hc-AFP3 transcripts were the most abundant in these tissues as measured by qRT-PCR. A polyclonal antibody that was cross-reactive with all four defensins, and probably recognizing a general plant defensin epitope, was used in fluorescence microscopy analysis to examine the presence of the peptides in the root tip and BLCs. Data confirmed the peptides present in the root tip tissues, the mucilage sheath and the BLCs. This study provides a link between defensin peptides and BLCs, both embedded in a protective pectin mucilage sheath, during normal plant growth and development. The presence of the Hc-AFP3 defensin peptides in the BLCs suggests a role for these cells in root protection. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

The Brassicaceae species Heliophila coronopifolia produces root border-like cells that protect the root tip and secrete defensin peptides

PubMed Central

Weiller, Florent; Young, Philip; Driouich, Azeddine; Vivier, Melané A.

2017-01-01

Background and Aims Root border cells and border-like cells (BLCs), the latter originally described in Arabidopsis thaliana, have been described as cells released at the root tips of the species in which they occur. BLCs are thought to provide protection to root meristems similar to classical root border cells. In addition, four defensin peptides (Hc-AFP1–4) have previously been characterized from Heliophila coronopifolia, a South African semi-desert flower, and found to be strongly antifungal. This provided an opportunity to evaluate if the BLCs of H. coronopifolia indeed produce these defensins, which would provide evidence towards a defence role for BLCs. Methods Fluorescence microscopy, using live-cell-imaging technology, was used to characterize the BLCs of H. coronopifolia. Quantitative real-time PCR (qRT-PCR) analysis and immunofluorescence microscopy was used to characterize these defensin peptides. Key Results BLCs originated at the root apical meristem and formed a protective sheath at the tip and along the sides as the root elongated in solid medium. BLCs have a cellulose-enriched cell wall, intact nuclei and are embedded in a layer of pectin-rich mucilage. Pectinase treatments led to the dissolution of the sheath and dissociation of the root BLCs. Hc-AFP1–4 genes were all expressed in root tissues, but Hc-AFP3 transcripts were the most abundant in these tissues as measured by qRT-PCR. A polyclonal antibody that was cross-reactive with all four defensins, and probably recognizing a general plant defensin epitope, was used in fluorescence microscopy analysis to examine the presence of the peptides in the root tip and BLCs. Data confirmed the peptides present in the root tip tissues, the mucilage sheath and the BLCs. Conclusions This study provides a link between defensin peptides and BLCs, both embedded in a protective pectin mucilage sheath, during normal plant growth and development. The presence of the Hc-AFP3 defensin peptides in the BLCs suggests a role for these cells in root protection. PMID:27481828

Differences in the Limits of Stability Between Older Rolling Walker Users and Older Single-Tip-Cane Users - A Preliminary Study.

PubMed

Liu, Hao Howe; Quiben, Myles; Holmes, Clayton; Connors, Michael; Salem, Yasser

To identify the differences in the limits of stability (LOS) between older rolling walker and single-tip-cane users. This was a matched paired t-test design with repeated measure. Eighteen older subjects were matched based on age, gender, and functional level. The subjects were assessed using the multidirectional reach test initially and 5-month later in four directions: forward, backward, leftward, and rightward. Initially, there were no differences between cane users and rolling walker users in the LOS in all directions. However, 5-month later, the cane users who held their canes in their right hand had significantly better stability in forward and rightward reach than the walker users (p < .05). Further, the walker users demonstrated significantly decreased functional reach in forward reach (p < .05). Cane users might have better stability than walker users in the forward direction and in the direction toward the side holding the cane. This study may provide guide for clinicians including nurses for selecting appropriate rehabilitative interventions for older adults using walkers and canes.

The Flying Diamond: A joined aircraft configuration design project, volume 1

NASA Technical Reports Server (NTRS)

Ball, Chris; Czech, Joe; Lentz, Bryan; Kobashigawa, Daryl; Oishi, Curtis; Poladian, David

1988-01-01

The results of the analysis conducted on the Joined Wing Configuration study are presented. The joined wing configuration employs a conventional fuselage and incorporates two wings joined together near their tips to form a diamond shape in both plan view and front view. The arrangement of the lifting surfaces uses the rear wing as a horizontal tail and as a forward wing strut. The rear wing has its root at the tip of the vertical stabilizer and is structurally attached to the trailing edge of the forward wing. This arrangement of the two wings forms a truss structure which is inherently resistant to the aerodynamic bending loads generated during flight. This allows for a considerable reduction in the weight of the lifting surfaces. With smaller internal wing structures needed, the Joined Wing may employ thinner wings which are more suitable for supersonic and hypersonic flight, having less induced drag than conventional cantilever winged aircraft. Inherent in the Joined Wing is the capability of the generation of direct lift and side force which enhance the performance parameters.

The Monorail Technique to Overcome Difficult Anatomical Course During Implantation of Central Venous Port via the Left Internal Jugular Vein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Eu Hyun, E-mail: doorihyun6@gmail.com; Oh, Jung Suk; Chun, Ho Jong

PurposeThe study aimed to introduce a monorail technique to overcome difficult anatomical course via left internal jugular vein in implantable port insertion.MethodsFrom 2007 to 2016, a total of 9346 patients were referred for implantable port insertion in our interventional unit, among which 79 cases were requested to insert on the left side. Our monorail technique was applied only when the technical challenge of the catheter tip entering the azygos vein instead of the superior vena cava occurred (n = 7). The technique consists of puncturing at the distal tip of the port catheter with a 21-gauge micropuncture needle and advancing a 0.018-in.more » hair-wire to guide and provide support for pre-assembled port.ResultsThe monorail technique was performed in seven patients and all but one case were technically successful, showing a technical success rate of 85.7%. There were no immediate or delayed complications.ConclusionsThe monorail technique is helpful to overcome the difficult anatomical course via left internal jugular vein in implantable port insertion.« less

Optical Tip Clearance Measurements as a Tool for Rotating Disk Characterization

PubMed Central

García, Iker; Zubia, Joseba; Beloki, Josu; Arrue, Jon; Durana, Gaizka; Aldabaldetreku, Gotzon

2017-01-01

An experimental investigation on the vibrational behavior of a rotating disk by means of three optical fiber sensors is presented. The disk, which is a scale model of the real disk of an aircraft engine, was assembled in a wind tunnel in order to simulate real operation conditions. The pressure difference between the upstream and downstream sides of the disk causes an airflow that might force the disk to vibrate. To characterize this vibration, a set of parameters was determined by measuring the tip clearance of the disk: the amplitude, the frequency and the number of nodal diameters in the disk. All this information allowed the design of an upgraded prototype of the disk, whose performance was also characterized by the same method. An optical system was employed for the measurements, in combination with a strain gauge mounted on the disk surface, which served to confirm the results obtained. The data of the strain gauge coincided closely with those provided by the optical fiber sensors, thus demonstrating the suitability of this innovative technique to evaluate the vibrational behavior of rotating disks. PMID:28098845

Graviresponsiveness and the Development of Columella Tissue in Primary and Lateral Roots of Ricinus communis1

PubMed Central

Moore, Randy; Pasieniuk, John

1984-01-01

Half-tipped primary and lateral roots of Ricinus communis cv Hale bend toward the side of the root on which the intact half-tip remains. Therefore, the minimal graviresponsiveness of lateral roots is not due to the inability of their caps to produce growth effectors (presumably inhibitors). The columella tissues of primary (i.e. graviresponsive) roots are (a) 4.30 times longer, (b) 2.95 times wider, (c) 37.4 times more voluminous, and (d) composed of 17.2 times more cells than those of lateral roots. The onset of positive gravitropism by lateral roots is positively correlated with a (a) 2.99-fold increase in length, (b) 2.63-fold increase in width, and (c) 20.7-fold increase in volume of their columella tissues. We propose that the minimal graviresponsiveness of lateral roots is due to the small size of their columella tissues, which results in their caps being unable to (a) establish a concentration gradient of the effector sufficient to induce gravicurvature and (b) produce as much of the effector as caps of graviresponsive roots. Images Fig. 1 PMID:11540818

The Monorail Technique to Overcome Difficult Anatomical Course During Implantation of Central Venous Port via the Left Internal Jugular Vein.

PubMed

Kim, Eu Hyun; Oh, Jung Suk; Chun, Ho Jong; Lee, Hae Giu; Choi, Byung Gil

2017-03-01

The study aimed to introduce a monorail technique to overcome difficult anatomical course via left internal jugular vein in implantable port insertion. From 2007 to 2016, a total of 9346 patients were referred for implantable port insertion in our interventional unit, among which 79 cases were requested to insert on the left side. Our monorail technique was applied only when the technical challenge of the catheter tip entering the azygos vein instead of the superior vena cava occurred (n = 7). The technique consists of puncturing at the distal tip of the port catheter with a 21-gauge micropuncture needle and advancing a 0.018-in. hair-wire to guide and provide support for pre-assembled port. The monorail technique was performed in seven patients and all but one case were technically successful, showing a technical success rate of 85.7%. There were no immediate or delayed complications. The monorail technique is helpful to overcome the difficult anatomical course via left internal jugular vein in implantable port insertion.

Quantitative study of fungiform papillae and taste buds on the cat's tongue.

PubMed

Robinson, P P; Winkles, P A

1990-01-01

The number of fungiform papillae has been counted on the tongues of six adult cats and of kittens both at birth and aged 2 and 4 months. Papillae were sampled from different regions of the tongue, and their size and the number of taste buds they contained were determined using histological sections taken parallel to the tongue surface. There were approximately 250 fungiform papillae on the tongues of the adult cats, the papillae were most numerous at the tip of the tongue, and there was no significant difference between the number of papillae on each side. The size of the papillae increased from a mean maximum diameter of 0.28 mm at the tip of the tongue to 0.48 mm at the back; the mean number of taste buds increased correspondingly from 6.9 to 16.6. The kitten tongues had a number and distribution of fungiform papillae similar to that found in the adults. In the neonate, papillae were smaller and contained fewer taste buds; these parameters increased with the corresponding increase in tongue size in the 2- and 4-month-old kittens.

[Development of a new technique to detect the laterality of microscopic hematuria by means of gas cystoscopy].

PubMed

Kamoi, K; Teraski, T; Kojima, M; Uchida, M; Watanabe, H

1996-04-01

We developed a new technique to determine the laterality of microscopic hematuria by means of gas cystoscopy. An originally designed catheter system consisted of two catheters. On the tip of an inner catheter, a urine dipstick for blood was attached, with a cap on the tip of an outer catheter to keep the dipstick dry. In order to react a dipstick with the urine coming out from a ureteral orifice in the bladder, CO2 was insufflated into the bladder through a cystoscope (gas cystoscopy). The laterality of microscopic hematuria was determined in the bladder, based on the color reaction on the dipstick. This technique was performed successfully in 14 (88%) of 16 cases with microscopic hematuria. The laterality of microscopic hematuria was determined to be ipsilateral in 6 patients, which coincided with the side of a urological upper urinary tract disorder. In contract, bilateral microscopic hematuria was confirmed in 8 patients with glomerular disorders. The diagnostic process in patients with microscopic hematuria remains unsolved for urologists and nephrologists. This technique may provide a new approach in diagnosing microscopic hematuria.

Large deflections and vibrations of a tip pulled beam with variable transversal section

NASA Astrophysics Data System (ADS)

Kurka, P.; Izuka, J.; Gonzalez, P.; Teixeira, L. H.

2016-10-01

The use of long flexible probes in outdoors exploration vehicles, as opposed to short and rigid arms, is a convenient way to grant easier access to regions of scientific interest such as terrain slopes and cliff sides. Longer and taller arms can also provide information from a wider exploration horizon. The drawback of employing long and flexible exploration probes is the fact that its vibration is not easily controlled in real time operation by means of a simple analytic linear dynamic model. The numerical model required to describe the dynamics of a very long and flexible structure is often very large and of slow computational convergence. The present work proposes a simplified numerical model of a long flexible beam with variable cross section, which is statically deflected by a pulling cable. The paper compares the proposed simplified model with experimental data regarding the static and dynamic characteristics of a beam with variable cross section. The simulations show the effectiveness of the simplified dynamic model employed in an active control loop to suppress tip vibrations of the beam.

High-crystalline medium-band-gap polymers consisting of benzodithiophene and benzotriazole derivatives for organic photovoltaic cells.

PubMed

Kim, Ji-Hoon; Song, Chang Eun; Shin, Nara; Kang, Hyunbum; Wood, Sebastian; Kang, In-Nam; Kim, Bumjoon J; Kim, Bongsoo; Kim, Ji-Seon; Shin, Won Suk; Hwang, Do-Hoon

2013-12-26

Two semiconducting conjugated polymers were synthesized via Stille polymerization. The structures combined unsubstituted or (triisopropylsilyl)ethynyl (TIPS)-substituted 2,6-bis(trimethylstannyl)benzo[1,2-b:4.5-b']dithiophene (BDT) as a donor unit and benzotriazole with a symmetrically branched alkyl side chain (DTBTz) as an acceptor unit. We investigated the effects of the different BDT moieties on the optical, electrochemical, and photovoltaic properties of the polymers and the film crystallinities and carrier mobilities. The optical-band-gap energies were measured to be 1.97 and 1.95 eV for PBDT-DTBTz and PTIPSBDT-DTBTz, respectively. Bulk heterojunction photovoltaic devices were fabricated and power conversion efficiencies of 5.5% and 2.9% were found for the PTIPSBDT-DTBTz- and PBDT-DTBTz-based devices, respectively. This difference was explained by the more optimal morphology and higher carrier mobility in the PTIPSBDT-DTBTz-based devices. This work demonstrates that, under the appropriate processing conditions, TIPS groups can change the molecular ordering and lower the highest occupied molecular orbital level, providing the potential for improved solar cell performance.

Noncontact Measurement Of Sizes And Eccentricities Of Holes

NASA Technical Reports Server (NTRS)

Chern, Engmin J.

1993-01-01

Semiautomatic eddy-current-probe apparatus makes noncontact measurements of nominally round holes in electrically conductive specimens and processes measurement data into diameters and eccentricities of holes. Includes x-y translation platform, which holds specimen and moves it horizontally. Probe mounted on probe scanner, positioning probe along vertical (z) direction and rotates probe about vertical axis at preset low speed. Eddy-current sensing coil mounted in side of probe near tip. As probe rotates, impedance analyzer measures electrical impedance (Z) of coil as function of instantaneous rotation angle. Translation and rotation mechanisms and impedance analyzer controlled by computer, which also processes impedance-measurement data.

Interferometric fibre-optic curvature sensing for structural, directional vibration measurements

NASA Astrophysics Data System (ADS)

Kissinger, Thomas; Chehura, Edmon; James, Stephen W.; Tatam, Ralph P.

2017-06-01

Dynamic fibre-optic curvature sensing using fibre segment interferometry is demonstrated using a cost-effective rangeresolved interferometry interrogation system. Differential strain measurements from four fibre strings, each containing four fibre segments of gauge length 20 cm, allow the inference of lateral vibrations as well as the direction of the vibration of a cantilever test object. Dynamic tip displacement resolutions in the micrometre range over a 21 kHz interferometric bandwidth demonstrate the suitability of this approach for highly sensitive fibre-optic directional vibration measurements, complementing existing laser vibrometry techniques by removing the need for side access to the structure under test.

Multiplexing curvature sensors using fibre segment interferometry for lateral vibration measurements

NASA Astrophysics Data System (ADS)

Kissinger, Thomas; Chehura, Edmon; James, Stephen W.; Tatam, Ralph P.

2017-04-01

Dynamic fibre-optic curvature sensing is demonstrated by interrogating chains of fibre segments, separated by broadband Bragg grating reflectors, using range-resolved interferometry (RRI). Four fibre strings, containing four fibre segments each of gauge length 20 cm, are attached to the opposing sides of a support structure and the resulting differential strain measurements allow inference of lateral displacements of a cantilever test object. Dynamic tip displacement resolutions in the micrometre range at an interferometric bandwidth of 21 kHz demonstrate the suitability of this approach for highly sensitive and cost-effective fibre-optic directional vibration measurements of smart structures.

DESIGN ANALYSIS OF RADIAL INFLOW TURBINES

NASA Technical Reports Server (NTRS)

Glassman, A. J.

1994-01-01

This program performs a velocity-diagram analysis required for determining geometry and estimating performance for radial-inflow turbines. Input design requirements are power, mass flow rate, inlet temperature and pressure, and rotative rate. The design variables include stator-exit angle, rotor-exit-tip to rotor-inlet radius ratio, rotor-exit-hub to tip radius ratio, and the magnitude and radial distribution of rotor-exit tangential velocity. The program output includes diameters, total and static efficiences, all absolute and relative temperatures, pressures, and velocities, and flow angles at stator inlet, stator exit, rotor inlet, and rotor exit. Losses accounted for in this program by the internal loss model are three-dimensional (profile plus end wall) viscous losses in the stator and the rotor, the disk-friction loss on the back side of the rotor, the loss due to the clearance between the rotor tip and the outer casing, and the exit velocity loss. The flow analysis is one-dimensional at the stator inlet, stator exit, and rotor inlet, each of these calculation stations being at a constant radius. At the rotor exit where there is a variation in flow-field radius, an axisymmetric two-dimensional analysis is made using constant height sectors. Simple radial equilibrium is used to establish the static pressure gradient at the rotor exit. This program is written in FORTRAN V and has been implemented on a UNIVAC 1100 series computer with a memory requirement of approximately 22K of 36 bit words.

Monocular tool control, eye dominance, and laterality in New Caledonian crows.

PubMed

Martinho, Antone; Burns, Zackory T; von Bayern, Auguste M P; Kacelnik, Alex

2014-12-15

Tool use, though rare, is taxonomically widespread, but morphological adaptations for tool use are virtually unknown. We focus on the New Caledonian crow (NCC, Corvus moneduloides), which displays some of the most innovative tool-related behavior among nonhumans. One of their major food sources is larvae extracted from burrows with sticks held diagonally in the bill, oriented with individual, but not species-wide, laterality. Among possible behavioral and anatomical adaptations for tool use, NCCs possess unusually wide binocular visual fields (up to 60°), suggesting that extreme binocular vision may facilitate tool use. Here, we establish that during natural extractions, tool tips can only be viewed by the contralateral eye. Thus, maintaining binocular view of tool tips is unlikely to have selected for wide binocular fields; the selective factor is more likely to have been to allow each eye to see far enough across the midsagittal line to view the tool's tip monocularly. Consequently, we tested the hypothesis that tool side preference follows eye preference and found that eye dominance does predict tool laterality across individuals. This contrasts with humans' species-wide motor laterality and uncorrelated motor-visual laterality, possibly because bill-held tools are viewed monocularly and move in concert with eyes, whereas hand-held tools are visible to both eyes and allow independent combinations of eye preference and handedness. This difference may affect other models of coordination between vision and mechanical control, not necessarily involving tools. Copyright © 2014 Elsevier Ltd. All rights reserved.

Caractérisation aérodynamique d'un rotor éolien en site naturel

NASA Astrophysics Data System (ADS)

Fabre, B.; Coudeville, H.

1991-03-01

The C_p/V_s curve (aerodynamic power coefficient versus tip-speed ratio) may be obtained in the field, therefore with different windspeeds, and to varying rotor speed, whithout selection of measures by steady state criterion. Experimentation is made on a small windmill with a straight blades Darrieus turbine and an eddy current converter. It allows us to display the conditions for a satisfying characterisation. So, the histogram of tip-speed ratio's instantaneous values must be as flat as it is possible, this on both sides of the tip-speed ratio's value for which the power coefficient is maximum. La courbe du coefficient de puissance aérodynamique (C_p) en fonction de la vitesse spécifique (V_s) peut être obtenue en champ libre, à vitesse de rotation variable et sans sélection des mesures par des critères de stabilité. L'expérimentation sur un système éolien composé d'un rotor Darrieus à pales droites associé à un convertisseur mécano-thermique nous a permis de mettre en évidence les conditions d'une caractérisation correcte. Notamment, l'histogramme des valeurs instantanées, acquises et traitées, de la vitesse spécifique doit être le plus plat possibie sur une large zone de part et d'autre de la valeur donnant le coefficient de puissance maximal.

A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes

PubMed Central

Manjila, Sunil; Mencattelli, Margherita; Rosa, Benoit; Price, Karl; Fagogenis, Georgios; Dupont, Pierre E.

2017-01-01

OBJECTIVE Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments—a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)—is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy. METHODS A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig. RESULTS Testing in porcine brains confirmed the multiport endoscope’s ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device’s utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°. CONCLUSIONS The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy. PMID:27581309

Asymmetrical development of root endodermis and exodermis in reaction to abiotic stresses

PubMed Central

Líška, Denis; Martinka, Michal; Kohanová, Jana; Lux, Alexander

2016-01-01

Background and Aims In the present study, we show that development of endodermis and exodermis is sensitively regulated by water accessibility. As cadmium (Cd) is known to induce xeromorphic effects in plants, maize roots were exposed also to Cd to understand the developmental process of suberin lamella deposition in response to a local Cd source. Methods In a first experiment, maize roots were cultivated in vitro and unilaterally exposed to water-containing medium from one side and to air from the other. In a second experiment, the roots were placed between two agar medium layers with a strip of Cd-containing medium attached locally and unilaterally to the root surface. Key Results The development of suberin lamella (the second stage of exodermal and endodermal development) started asymmetrically, preferentially closer to the root tip on the side exposed to the air. In the root contact with Cd in a spatially limited area exposed to one side of the root, suberin lamella was preferentially developed in the contact region and additionally along the whole length of the root basipetally from the contact area. However, the development was unilateral and asymmetrical, facing the treated side. The same pattern occurred irrespective of the distance of Cd application from the root apex. Conclusions These developmental characteristics indicate a sensitive response of root endodermis and exodermis in the protection of vascular tissues against abiotic stresses. PMID:27112163

Morphometric Analysis of the Occipital Condyle and Its Surgical Importance

PubMed Central

Das, Sushant Swaroop; Vasudeva, Neelam

2016-01-01

Introduction The Occipital Condyle (OC) is an integral component of craniovertebral region which is predisposed to a wide array of traumatic, degenerative and neoplastic diseases. Frequent surgical interventions of OC are required for successful management of these conditions. Hence a meticulous anatomical knowledge of the OC is vital but variability in morphometric dimensions exist amongst different races and hinder the standardization of measurements. Aim The aim of this study was to present a morphometric reference database for OC of the Indian population and enable comparisons with other populations. Materials and Methods The study was performed on 228 OC of 114 adult human skulls. Linear measurements of the OC were taken with the help of digital Vernier’s Calliper and angular measurements were determined with software Image J. Statistical Analysis Mean and standard deviation of the morphometric parameters taken into account were analysed. The comparison of morphometric dimensions of the right and left sides was carried out using Student’s t-test and p-value was calculated. Results The morphometric analysis of the OC established that mean width was larger (12.97 mm) in Indians population when compared to other races. The anterior and posterior intercondylar distances as well as the distances between the tips of OC and opisthion and basion were observed to be shorter in Indians. We found a significant difference (p=0.01) among the distance between Posterior tip of Occipital Condyle (POC) and basion of the right and left sides. The sagittal condylar angle and sagittal intercondylar angle were found to be greater in our study when compared to other researchers. There existed a highly significant difference (p=0.001) between the sagittal condylar angles of the right and left sides. Conclusion The present morphometric study would be valuable for the successful instrumentation of the OC as wider and ventrally oriented OC as well as smaller intercondylar distances may pose challenge to the surgeons during condylectomy. The data of present study offer anatomical reference to the surgeons and would be helpful in designing implants for the OC. PMID:28050351

Spring frost vulnerability of sweet cherries under controlled conditions

NASA Astrophysics Data System (ADS)

Matzneller, Philipp; Götz, Klaus-P.; Chmielewski, Frank-M.

2016-01-01

Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar `Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations.

Three-finger tracheal palpation to guide endotracheal tube depth in children.

PubMed

Gamble, Jonathan J; McKay, William P; Wang, Andrew F; Yip, Kinsha A; O'Brien, Jennifer M; Plewes, Christopher E

2014-10-01

Accurate endotracheal tube (ETT) depth is critical, especially in children. The current tools used to guide appropriate ETT depth have significant limitations. To evaluate the utility of tracheal palpation in the neck to guide appropriate ETT placement in children. A prospective observational study with a convenience sample of 50 children was conducted. During intubation, an investigator palpated the trachea with three fingertips side-by-side extending upward from the suprasternal notch. The anesthesiologist advanced the ETT slowly until palpated at the sternal notch. The investigator stated ETT palpation certainty as 'strongly felt', 'weakly felt', or 'not felt.' Final ETT position was determined by bronchoscopy and categorized as 'ETT too shallow' (tip in proximal ¼ of trachea), 'ETT too deep' (tip in distal ¼ of trachea), or 'ETT placement satisfactory' (between those extremes). Thirty boys and 20 girls undergoing dental surgery with nasal intubation were recruited (median age 4.4 years; range 2.0-10.8). The ETT (all ≥4 mm ID) was palpable at the sternal notch in all patients: 46 of 50 strongly palpable and 4 of 50 weakly palpable. The experimental methods led to satisfactory ETT placement in 49 of 50 patients, too deep in 1 of 50 patients. Compared with the Pediatrics Advanced Life Support (PALS) predictive formula, satisfactory placement would have been 41 of 50 patients (P < 0.008). Number needed to treat is 6.3 for improvement over the PALS method. The use of tracheal palpation to guide ETT placement has excellent clinical performance and better guides appropriate ETT depth than the PALS formula in our study population. © 2014 John Wiley & Sons Ltd.

Spring frost vulnerability of sweet cherries under controlled conditions.

PubMed

Matzneller, Philipp; Götz, Klaus-P; Chmielewski, Frank-M

2016-01-01

Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar 'Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations.

Kinematics of fault-related folding derived from a sandbox experiment

NASA Astrophysics Data System (ADS)

Bernard, Sylvain; Avouac, Jean-Philippe; Dominguez, StéPhane; Simoes, Martine

2007-03-01

We analyze the kinematics of fault tip folding at the front of a fold-and-thrust wedge using a sandbox experiment. The analog model consists of sand layers intercalated with low-friction glass bead layers, deposited in a glass-sided experimental device and with a total thickness h = 4.8 cm. A computerized mobile backstop induces progressive horizontal shortening of the sand layers and therefore thrust fault propagation. Active deformation at the tip of the forward propagating basal décollement is monitored along the cross section with a high-resolution CCD camera, and the displacement field between pairs of images is measured from the optical flow technique. In the early stage, when cumulative shortening is less than about h/10, slip along the décollement tapers gradually to zero and the displacement gradient is absorbed by distributed deformation of the overlying medium. In this stage of detachment tip folding, horizontal displacements decrease linearly with distance toward the foreland. Vertical displacements reflect a nearly symmetrical mode of folding, with displacements varying linearly between relatively well defined axial surfaces. When the cumulative slip on the décollement exceeds about h/10, deformation tends to localize on a few discrete shear bands at the front of the system, until shortening exceeds h/8 and deformation gets fully localized on a single emergent frontal ramp. The fault geometry subsequently evolves to a sigmoid shape and the hanging wall deforms by simple shear as it overthrusts the flat ramp system. As long as strain localization is not fully established, the sand layers experience a combination of thickening and horizontal shortening, which induces gradual limb rotation. The observed kinematics can be reduced to simple analytical expressions that can be used to restore fault tip folds, relate finite deformation to incremental folding, and derive shortening rates from deformed geomorphic markers or growth strata.

Effect of dopant density on contact potential difference across n-type GaAs homojunctions using Kelvin Probe Force Microscopy

NASA Astrophysics Data System (ADS)

Boumenou, C. Kameni; Urgessa, Z. N.; Djiokap, S. R. Tankio; Botha, J. R.; Nel, J.

2018-04-01

In this study, cross-sectional surface potential imaging of n+/semi-insulating GaAs junctions is investigated by using amplitude mode kelvin probe force microscopy. The measurements have shown two different potential profiles, related to the difference in surface potential between the semi-insulating (SI) substrate and the epilayers. It is shown that the contact potential difference (CPD) between the tip and the sample is higher on the semi-insulating substrate side than on the n-type epilayer side. This change in CPD across the interface has been explained by means of energy band diagrams indicating the relative Fermi level positions. In addition, it has also been found that the CPD values across the interface are much smaller than the calculated values (on average about 25% of the theoretical values) and increase with the electron density. Therefore, the results presented in study are only in qualitative agreement with the theory.

Influence of Beam Rotation on the Response of Cantilevered Flow Energy Harvesters Exploiting the Galloping Instability

NASA Astrophysics Data System (ADS)

Noel, James H.

Energy harvesters are scalable devices that generate microwatt to milliwatt power levels by scavenging energy from their ambient natural environment. Applications of such devices are numerous, ranging from wireless sensing to biomedical implants. A particular type of energy harvester is a device which converts the momentum of an incident fluid flow into electrical output by using flow-induced instabilities such as galloping, flutter, vortex shedding and wake galloping. Galloping flow energy harvesters (GFEHs), which represent the core of this thesis, consist of a prismatic tip body mounted on a long, thin cantilever beam fixed on a rigid base. When the bluff body is placed such that its leading edge faces a moving fluid, the flow separates at the edges of the leading face causing shear layers to develop behind the bluff face. The shear layer interacts with the surface area of the afterbody. An asymmetric condition in the shear layers causes a net lift which incites motion. This causes the beam to oscillate periodically at or near the natural frequency of the system. The periodic strain developed near the base of the oscillating beam is then transformed into electricity by attaching a piezoelectric layer to either side of the beam surface. This thesis focuses on characterizing the influence of the rotation of the beam tip on the response and output power of GFEHs. Previous modeling efforts of GFEHs usually adopt two simplifying assumptions. First, it is assumed that the tip rotation of the beam is arbitrarily small and hence can be neglected. Second, it is assumed that the quasi-steady assumption of the aerodynamic force can be adopted even in the presence of tip rotation. Although the validity of these two assumptions becomes debatable in the presence of finite tip rotations, which are common to occur in GFEHs, none the previous research studies have systematically addressed the influence of finite tip rotations on the validity of the quasi-steady assumption and the response of cantilevered flow energy harvesters. To this end, the first objective of this thesis is to investigate the influence of the tip rotation on the output power of energy harvesters under the quasi-steady assumption. It is shown that neglecting the tip rotation will cause significant over-prediction of the output power even for small tip rotations. This thesis further assesses the validity of the quasi-steady assumption of the aerodynamic force in the presence of tip rotations using extensive experiments. It is shown that the quasi-steady model fails to accurately predict the behavior of square and trapezoidal prisms mounted on a cantilever beam and undergoing galloping oscillations. In particular, it is shown that the quasi-steady model under-predicts the amplitude of oscillation because it fails to consider the effect of body rotation. Careful analysis of the experimental data indicates that, unlike the quasi-steady aerodynamic lift force which depends only on the angle of attack, the effective aerodynamic curve is a function of both the angle of attack and the upstream flow velocity when the effects of body rotation are included. Nonetheless, although the quasi-steady assumption fails, the remarkable result is that the overall structure of the aerodynamic model remains intact, permitting the use of aerodynamic force surfaces to capture the influence of tip rotation. The second objective of this thesis is to present an approach to optimize the geometry of the bluff body to improve the performance of flow energy harvesters. It is shown that attaching a splitter plate to the afterbody of the prism can improve the output power of the device by as much as 60% for some cases. By increasing the reattachment angle of the shear layer and producing additional flow recirculation bubbles, the extension of the body using the splitter plate increases the useful range of the galloping instability for energy harvesting.

TRGB Distances to Galaxies in Front of the Virgo Cluster

NASA Astrophysics Data System (ADS)

Karachentsev, Igor D.; Makarova, Lidia N.; Tully, R. Brent; Rizzi, Luca; Shaya, Edward J.

2018-05-01

Tip of the red giant branch distances are acquired from Hubble Space Telescope images for 16 galaxies to the foreground of the Virgo Cluster. The new distances with 5% accuracy, combined with archival measurements, tightly constrain the near-side location of the onset of infall into the Virgo Cluster to be 7.3 ± 0.3 Mpc from the cluster, reaching within 9 Mpc of the Milky Way. The mass within this turnaround radius about the cluster is (8.3 ± 0.9) × 1014 M ⊙. Color–magnitude diagrams are provided for galaxies in this study and there is a brief discussion of their group affiliations.

Stockton Lake Survey and Assessment. National Register Assessment of Prehistoric Archeological Sites 23DA407 and 23DA408 and Historic Properties Survey in the Stockton Lake Project, Cedar and Dade Counties, Missouri

DTIC Science & Technology

1993-01-01

Elevation 890 HPA Reports Stockton Lake Survey and Assessment page 38 23CE46723CE398 .1 IYAR CPA .COWN if Y 344 CD meer 50 suvexae sitvey area transect...Stockton Lake. The shelter is within the emergency floodpool of the lake. Some deposits north of the beck wall appuoxitmtely 5 to 6 feet my stiU be...point ha some tip damage and one baa corner mintin Arrow point sftm (Sallisaw variant?) 1 0.9 Am*a between remaining side notch and coaesve bowe

Dendritic sidebranching in the three-dimensional symmetric model in the presence of noise

NASA Technical Reports Server (NTRS)

Langer, J. S.

1987-01-01

The time-dependent behavior of sidebranching deformations in the three-dimensional symmetric model of dendritic solidification is studied within a WKB approximation. Localized wave packets generated by pulses in the neighborhood of the tip are found to grow in amplitude and to spread and stretch as they move down the sides of the dendrite. This behavior is shown to imply that noise in the solidifying medium is selectively amplified in such a way as to produce a fluctuating train of sidebranches in qualitative agreement with experimental observations. A rough estimate indicates that purely thermal noise is probably not quite strong enough to fit the data.

Cardioembolic strokes resulting from a self-inflicted needle puncture involving both sides of the heart.

PubMed

Tan, Mark Zheng Yi; Brunswicker, Annemarie; Abdelraheem, Shamsaldeen; Sheehan, Alison

2017-04-01

Foreign bodies in the heart are rare occurrences with a limited evidence base to guide recommendations on management. We report a case of multiple cardioembolic strokes as a result of a self-inflicted sewing needle puncture from the anterior chest through the right ventricle and interventricular septum with its tip in the left ventricle close to the subvalvular apparatus in a 39-year-old psychiatric patient. We discuss issues surrounding decision making and ongoing care and highlight the importance of further follow-up and reporting of cases to form a robust evidence base to guide future recommendations. © 2017, Wiley Periodicals, Inc.

Pain is Associated to Clinical, Psychological, Physical, and Neurophysiological Variables in Women With Carpal Tunnel Syndrome.

PubMed

Fernández-Muñoz, Juan J; Palacios-Ceña, María; Cigarán-Méndez, Margarita; Ortega-Santiago, Ricardo; de-la-Llave-Rincón, Ana I; Salom-Moreno, Jaime; Fernández-de-las-Peñas, César

2016-02-01

To investigate potential relationships of clinical (age, function, side of pain, years with pain), physical (cervical range of motion, pinch grip force), psychological (depression), and neurophysiological (pressure and thermal pain thresholds) outcomes and hand pain intensity in carpal tunnel syndrome (CTS). Two hundred and forty-four (n=224) women with CTS were recruited. Demographic data, duration of the symptoms, function and severity of the disease, pain intensity, depression, cervical range of motion, pinch tip grip force, heat/cold pain thresholds (HPT/CPT), and pressure pain thresholds (PPT) were collected. Correlation and regression analysis were performed to determine the association among those variables and to determine the proportions of explained variance in hand pain intensity. Significant negative correlations existed between the intensity of pain and PPTs over the radial nerve, C5/C6 zygapophyseal joint, carpal tunnel and tibialis anterior muscle, HPT over the carpal tunnel, cervical extension and lateral-flexion, and thumb-middle, fourth, and little finger pinch tip forces. Significant positive correlations between the intensity of hand pain with function and depression were also observed. Stepwise regression analyses revealed that function, thumb-middle finger pinch, thumb-little finger pinch, depression, PPT radial nerve, PPT carpal tunnel, and HPT carpal tunnel were significant predictors of intensity of hand pain (R²=0.364; R² adjusted=0.343; F=16.87; P<0.001). This study showed that 36.5% of the variance of pain intensity was associated to clinical (function), neurophysiological (localized PPT and HPT), psychological (depression), and physical (finger pinch tip force) outcomes in women with chronic CTS.

Imaging Electron Motion in a Few Layer MoS2 Device

NASA Astrophysics Data System (ADS)

Bhandari, S.; Wang, K.; Watanabe, K.; Taniguchi, T.; Kim, P.; Westervelt, R. M.

2017-06-01

Ultrathin sheets of MoS2 are a newly discovered 2D semiconductor that holds great promise for nanoelectronics. Understanding the pattern of current flow will be crucial for developing devices. In this talk, we present images of current flow in MoS2 obtained with a Scanned Probe Microscope (SPM) cooled to 4 K. We previously used this technique to image electron trajectories in GaAs/AlGaAs heterostructures and graphene. The charged SPM tip is held just above the sample surface, creating an image charge inside the device that scatters electrons. By measuring the change in resistance ΔR while the tip is raster scanned above the sample, an image of electron flow is obtained. We present images of electron flow in an MoS2 device patterned into a hall bar geometry. A three-layer MoS2 sheet is encased by two hBN layers, top and bottom, and patterned into a hall-bar with multilayer graphene contacts. An SPM image shows the current flow pattern from the wide contact at the end of the device for a Hall density n = 1.3×1012 cm-2. The SPM tip tends to block flow, increasing the resistance R. The pattern of flow was also imaged for a narrow side contact on the sample. At density n = 5.4×1011 cm-2; the pattern seen in the SPM image is similar to the wide contact. The ability to image electron flow promises to be very useful for the development of ultrathin devices from new 2D materials.

ESD Test Apparatus for Soldering Irons

NASA Technical Reports Server (NTRS)

Sancho, Jose; Esser, Robert

2013-01-01

ESDA (Electrostatic Discharge Association) ESD STM 13.1-2000 requires frequent testing of the voltage leakage from the tip of a soldering iron and the resistance from the tip of the soldering iron to the common point ground. Without this test apparatus, the process is time-consuming and requires several wires, alligator clips, or test probes, as well as additional equipment. Soldering iron tips must be tested for electrostatic discharge risks frequently, and this typically takes a lot of time in setup and testing. This device enables the operator to execute the full test in one minute or less. This innovation is a simple apparatus that plugs into a digital multimeter (DMM) and the Common Point Ground (CPG) reference. It enables the user to perform two of the electrostatic discharge tests required in ESD STM 13.1-2000. The device consists of a small black box with two prongs sticking out of one end, two inputs on the opposite end (one of the inputs is used to connect the reference CPG to the DMM), and a metal tab on one side. Inside the box are wires, several washers of various materials, and assembly hardware (nuts and screws/bolts). The device is a passive electronic component that is plugged into a DMM. The operator sets the DMM to read voltage. The operator places the heated tip of the soldering iron onto the metal tab with a small amount of solder to ensure a complete connection. The voltage is read and recorded. The operator switches the DMM to read resistance. The operator places the heated tip of the soldering iron onto the metal tab with a small amount of solder to ensure a complete connection. The resistance is recorded. If the recorded voltage and resistance are below a number stated in ESDA ESD STM 13.1-2000, the test is considered to pass. The device includes all the necessary wiring internal to its body so the operator does not need to do any independent wiring, except for grounding. It uses a stack of high-thermal-resistance washers to minimize the heat transfer from the soldering iron to the wiring used to measure the resistance and voltages. This minimizes thermal error. The device allows very rapid execution of a test that is performed frequently.

Novel air-injection technique to locate the medial cut end of lacerated canaliculus.

PubMed

Liu, Bingqian; Li, Yonghao; Long, Chongde; Wang, Zhonghao; Liang, Xuanwei; Ge, Jian; Wang, Zhichong

2013-12-01

Locating the medial cut end of the severed canaliculus is the most difficult aspect of canalicular repair, especially in patients with more medial laceration, severe oedema, persistent errhysis and a narrow canaliculus. Irrigation is a widely used technique to identify the cut end; however, we found that air injected through the intact canaliculus with a straight needle failed to reflux when the common canaliculus or lacrimal sac was not blocked. We describe a simple, safe and efficient air-injection technique to identify the medial cut edge of a lacerated canaliculus. In this method, we initially submersed the medial canthus under normal saline, then injected filtered air through the intact canaliculus using a side port stainless steel probe with a closed round tip. The tip was designed to block the common canaliculus to form a relatively closed system. The efficiency of this novel air-injection technique was equivalent to the traditional technique but does not require the cooperation of the patient to blow air. Using this technique, the medial cut end was successfully identified by locating the air-bubble exit within minutes in 19 cases of mono-canalicular laceration without any complication.

Contact compliance effects in the frictional response of bioinspired fibrillar adhesives

PubMed Central

Piccardo, Marco; Chateauminois, Antoine; Fretigny, Christian; Pugno, Nicola M.; Sitti, Metin

2013-01-01

The shear failure and friction mechanisms of bioinspired adhesives consisting of elastomer arrays of microfibres terminated by mushroom-shaped tips are investigated in contact with a rigid lens. In order to reveal the interplay between the vertical and lateral loading directions, experiments are carried out using a custom friction set-up in which normal stiffness can be made either high or low when compared with the stiffness of the contact between the fibrillar adhesive and the lens. Using in situ contact imaging, the shear failure of the adhesive is found to involve two successive mechanisms: (i) cavitation and peeling at the contact interface between the mushroom-shaped fibre tip endings and the lens; and (ii) side re-adhesion of the fibre's stem to the lens. The extent of these mechanisms and their implications regarding static friction forces is found to depend on the crosstalk between the normal and lateral loading directions that can result in contact instabilities associated with fibre buckling. In addition, the effects of the viscoelastic behaviour of the polyurethane material on the rate dependence of the shear response of the adhesive are accounted for. PMID:23554349

Technological innovation in video-assisted thoracic surgery.

PubMed

Özyurtkan, Mehmet Oğuzhan; Kaba, Erkan; Toker, Alper

2017-01-01

The popularity of video-assisted thoracic surgery (VATS) which increased worldwide due to the recent innovations in thoracic surgical technics, equipment, electronic devices that carry light and vision and high definition monitors. Uniportal VATS (UVATS) is disseminated widely, creating a drive to develop new techniques and instruments, including new graspers and special staplers with more angulation capacities. During the history of VATS, the classical 10 mm 0° or 30° rigid rod lens system, has been replaced by new thoracoscopes providing a variable angle technology and allowing 0° and 120° range of vision. Besides, the tip of these novel thoracoscopes can be positioned away from the operating side minimize fencing with other thoracoscopic instruments. The curved-tip stapler technology, and better designed endostaplers helped better dissection, precision of control, more secure staple lines. UVATS also contributed to the development of embryonic natural orifice transluminal endoscopic surgery. Three-dimensional VATS systems facilitated faster and more accurate grasping, suturing, and dissection of the tissues by restoring natural 3D vision and the perception of depth. Another innovation in VATS is the energy-based coagulative and tissue fusion technology which may be an alternative to endostaplers.

A case of annular pancreas with Wirsung's duct encircling the duodenum: embryological hypothesis based on cholangiopancreatographic and immunohistochemical findings.

PubMed

Fukai, Manami; Kamisawa, Terumi; Horiguchi, Shin-Ichirou; Hishima, Tsunekazu; Kuruma, Sawako; Chiba, Kazuro; Koizumi, Satomi; Tabata, Taku; Nagao, Sayaka; Kikuyama, Masataka; Honda, Goro; Kurata, Masanao

2017-06-01

We present a resected case of annular pancreas in which Wirsung's duct encircled the duodenum and continued directly to the main pancreatic duct in the body and tail. Furthermore, Wirsung's duct coursed along the right side of the lower bile duct near the major duodenal papilla. Histologically, the islets of Langerhans in the annular pancreas were irregular in shape and were characterized by a striking abundance of pancreatic polypeptide (PP)-positive cells. The PP-rich area that encircled the duodenum was fused with the PP-poor area in the head of the pancreas. The following embryological hypothesis is proposed. The tip of the ventral pancreatic anlage adhered to the duodenal wall and stretched to form a ring during clockwise rotation. The rotation was incomplete, and the pancreatic duct did not cross over the lower bile duct. Since there was adequate ventral anlage in the lower part of the head of the pancreas, fusion between the ducts of the ventral and dorsal anlagen did not occur. The tip of the ventral anlage overgrew and adhered to the dorsal anlage, and the annular duct fused with the main duct of the dorsal anlage.

The Acoustic Lens Design and in Vivo Use of a Multifunctional Catheter Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

PubMed Central

Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Sahn, David

2009-01-01

A multifunctional 9F intracardiac imaging and electrophysiology mapping catheter was developed and tested to help guide diagnostic and therapeutic intracardiac electrophysiology (EP) procedures. The catheter tip includes a 7.25-MHz, 64-element, side-looking phased array for high resolution sector scanning. Multiple electrophysiology mapping sensors were mounted as ring electrodes near the array for electrocardiographic synchronization of ultrasound images. The catheter array elevation beam performance in particular was investigated. An acoustic lens for the distal tip array designed with a round cross section can produce an acceptable elevation beam shape; however, the velocity of sound in the lens material should be approximately 155 m/s slower than in tissue for the best beam shape and wide bandwidth performance. To help establish the catheter’s unique ability for integration with electrophysiology interventional procedures, it was used in vivo in a porcine animal model, and demonstrated both useful intracardiac echocardiographic visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheter also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. PMID:18407850

Excellent Field Emission Properties of Short Conical Carbon Nanotubes Prepared by Microwave Plasma Enhanced CVD Process

PubMed Central

2008-01-01

Randomly oriented short and low density conical carbon nanotubes (CNTs) were prepared on Si substrates by tubular microwave plasma enhanced chemical vapor deposition process at relatively low temperature (350–550 °C) by judiciously controlling the microwave power and growth time in C2H2 + NH3gas composition and Fe catalyst. Both length as well as density of the CNTs increased with increasing microwave power. CNTs consisted of regular conical compartments stacked in such a way that their outer diameter remained constant. Majority of the nanotubes had a sharp conical tip (5–20 nm) while its other side was either open or had a cone/pear-shaped catalyst particle. The CNTs were highly crystalline and had many open edges on the outer surface, particularly near the joints of the two compartments. These films showed excellent field emission characteristics. The best emission was observed for a medium density film with the lowest turn-on and threshold fields of 1.0 and 2.10 V/μm, respectively. It is suggested that not only CNT tip but open edges on the body also act as active emission sites in the randomly oriented geometry of such periodic structures.

A K(+)/H (+) P-ATPase transport in the accessory cell membrane of the blowfly taste chemosensilla sustains the transepithelial potential.

PubMed

Sollai, Giorgia; Solari, Paolo; Masala, Carla; Liscia, Anna; Crnjar, Roberto

2008-11-01

An electrogenic K(+) transport in the tormogen cell of insect chemosensilla is involved in the generation and maintenance of the transepithelial potential (TEP). To gain more information about the K(+) transport system underlying the TEP generation and the location of its components in the plasma membrane of the tormogen cell, we studied the effects of inhibitors of K(+)/H(+) P-ATPase (bafilomycin A1, omeprazole and Na-orthovanadate), of K(+)/Cl(-) co-transport (bumetanide), of Cl(-) channels (NPPB) and of a K(+) channel blocker (BaCl(2)). The relationship between TEP amplitude and spike firing activity was also studied. Experiments were performed on the labellar chemosensilla of the blowfly Protophormia terraenovae using a modified tip-recording technique. Results show that: (a) K(+)/H(+) P-ATPase inhibitors significantly decrease the TEP, when properly applied to the labellum for 20 min, so as to reach the basolateral side of the plasma membrane, while no effect was detected when applied to the apical side, (b) bumetanide, NPPB and BaCl(2) decrease the TEP value only when administered to the apical side, (c) spike activity is positively correlated with the TEP. A model is proposed of the active and passive K(+) transports sustaining the TEP associated with the blowfly chemosensilla.

Airframe Noise from a Hybrid Wing Body Aircraft Configuration

NASA Technical Reports Server (NTRS)

Hutcheson, Florence V.; Spalt, Taylor B.; Brooks, Thomas F.; Plassman, Gerald E.

2016-01-01

A high fidelity aeroacoustic test was conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel to establish a detailed database of component noise for a 5.8% scale HWB aircraft configuration. The model has a modular design, which includes a drooped and a stowed wing leading edge, deflectable elevons, twin verticals, and a landing gear system with geometrically scaled wheel-wells. The model is mounted inverted in the test section and noise measurements are acquired at different streamwise stations from an overhead microphone phased array and from overhead and sideline microphones. Noise source distribution maps and component noise spectra are presented for airframe configurations representing two different approach flight conditions. Array measurements performed along the aircraft flyover line show the main landing gear to be the dominant contributor to the total airframe noise, followed by the nose gear, the inboard side-edges of the LE droop, the wing tip/LE droop outboard side-edges, and the side-edges of deployed elevons. Velocity dependence and flyover directivity are presented for the main noise components. Decorrelation effects from turbulence scattering on spectral levels measured with the microphone phased array are discussed. Finally, noise directivity maps obtained from the overhead and sideline microphone measurements for the landing gear system are provided for a broad range of observer locations.

Fan-head shear rupture mechanism as a source of off-fault tensile cracking

NASA Astrophysics Data System (ADS)

Tarasov, Boris

2016-04-01

This presentation discusses the role of a recently identified fan-head shear rupture mechanism [1] in the creation of off-fault tensile cracks observed in earthquake laboratory experiments conducted on brittle photoelastic specimens [2,3]. According to the fan-mechanism the shear rupture propagation is associated with consecutive creation of small slabs in the fracture tip which, due to rotation caused by shear displacement of the fracture interfaces, form a fan-structure representing the fracture head. The fan-head combines such unique features as: extremely low shear resistance (below the frictional strength) and self-sustaining tensile stress intensification along one side of the interface. The variation of tensile stress within the fan-head zone is like this: it increases with distance from the fracture tip up to a maximum value and then decreases. For the initial formation of the fan-head high local stresses corresponding to the fracture strength should be applied in a small area, however after completions of the fan-head it can propagate dynamically through the material at low shear stresses (even below the frictional strength). The fan-mechanism allows explaining all unique features associated with the off-fault cracking process observed in photoelastic experiments [2,3]. In these experiments spontaneous shear ruptures were nucleated in a bonded, precut, inclined and pre-stressed interface by producing a local pressure pulse in a small area. Isochromatic fringe patterns around a shear rupture propagating along bonded interface indicate the following features of the off-fault tensile crack development: tensile cracks nucleate and grow periodically along one side of the interface at a roughly constant angle (about 80 degrees) relative to the shear rupture interface; the tensile crack nucleation takes place some distance behind the rupture tip; with distance from the point of nucleation tensile cracks grow up to a certain length within the rupture head zone; behind this zone static microcracks are left in the wake of the propagating rupture. Unfortunately, the modern technology used in these experiments is not able to identify the shear rupture mechanism itself operated within the narrow rupture interface. However, a special analysis of side effects accompanying the shear rupture propagation (including the off-fault tensile cracking) allows supposing that the failure process was governed by the fan-mechanism. 1. Tarasov, B.G. 2014. Hitherto unknown shear rupture mechanism as a source of instability in intact hard rocks at highly confined compression. Tectonophysics, 621, 69-84. 2. Griffith, W.A., Rosakis, A., Pollard, D.D. and Ko, C.W., 2009. Dynamic rupture experiments elucidate tensile crack development during propagating earthquake ruptures, Geology, pp 795-798. 3. Ngo, D., Huang, Y., Rosakis, A., Griffith, W.A., Pollard D. 2012. Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models. Journal of Geophysical Research, vol. 117, B01307, doi: 10.1029/2011JB008577 (2012).

Endosseous titanium implants as anchors for mesiodistal tooth movement in the beagle dog.

PubMed

Saito, S; Sugimoto, N; Morohashi, T; Ozeki, M; Kurabayashi, H; Shimizu, H; Yamasaki, K; Shiba, A; Yamada, S; Shibasaki, Y

2000-12-01

The purpose of this study was to determine the anchorage potential of titanium implants (Branemark; 3.75 x 7 mm) with the use of a sectional arch wire technique for orthodontic mesiodistal tooth movement, as assessed by the osseointegration of implants and tooth movement. Two implants were surgically placed in healed mandibular extraction sites of the second and third premolars on each side in 4 adult male beagle dogs. The implants were surgically uncovered 18 weeks later, and second-stage abutments with soldered edgewise tubes were attached. Segmented edgewise rectangular archwires (0.017 x 0. 025 inch) with a T-loop or an L-loop were placed between the implants and the fourth premolars on both sides as the anchorage unit. One segment in each dog served as a loaded side, and the archwire was calibrated to produce 200 g of lateral force on the fourth premolar. The contralateral segment served as an unloaded side and was not subjected to orthodontic force. Sectional wires were activated biweekly 24, 28, 28, and 32 weeks, respectively, depending on the magnitude and the appearance of mesial tipping movement of the fourth premolar. After mandibular impressions were taken to measure the distance between the first molar and the fourth premolar, the animals were euthanized and dissected mandibles were prepared. The specimens were then embedded in polyester resin and cut to take backscattered electron images. On the basis of these images, the percentage of peri-implant bone volume was calculated and defined as an index of osseointegration. The differences between the initial and final fourth premolar to first molar distances varied (7.40, 8.85, 10.50, and 3.30 mm) on the loaded side, whereas the unloaded side showed no movement. Not only was there no statistical difference in the percent of peri-implant bone volume between the loaded and unloaded sides, but there was also no statistical difference between the compression and tension sides in both loaded and unloaded implants, which suggests that the implants maintained rigid osseointegration. In conclusion, the present study demonstrated that endosseous titanium implants can function as anchors for long-term orthodontic mesiodistal movement.

Wind-tunnel test of an articulated helicopter rotor model with several tip shapes

NASA Technical Reports Server (NTRS)

Berry, J. D.; Mineck, R. E.

1980-01-01

Six interchangeable tip shapes were tested: a square (baseline) tip, an ogee tip, a subwing tip, a swept tip, a winglet tip, and a short ogee tip. In hover at the lower rotational speeds the swept, ogee, and short ogee tips had about the same torque coefficient, and the subwing and winglet tips had a larger torque coefficient than the baseline square tip blades. The ogee and swept tip blades required less torque coefficient at lower rotational speeds and roughly equivalent torque coefficient at higher rotational speeds compared with the baseline square tip blades in forward flight. The short ogee tip required higher torque coefficient at higher lift coefficients than the baseline square tip blade in the forward flight test condition.

Gecko-Inspired, Controlled Adhesion and Its Applications

NASA Astrophysics Data System (ADS)

Menguc, Yigit

This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles). So far synthetic gecko adhesives fail to capture this behavior and self-cleaning remains the least studied characteristic in the field gecko-inspired adhesives. In this work we use two distinct arrays of micropillars with mushroom-shaped tips made from polyurethane. The two geometries we use all have the same aspect ratios of pillar height to base diameter of about 2 to 1, and all have mushroom tips that are twice the diameter of base. The pillar tip diameters are 20 mum and 95 mum, and we will refer to them as the small and large pillars, respectively. We contaminate the adhesives with simulated dirt particles in the form of well-characterized soda lime glass spheres ranging in diameter from 1 to 250 mum. Both micropillar arrays recovered adhesive strength after contamination and cleaning through dry, shearing contact with glass. In a best case scenario, we found that large pillars contaminated with 150-250 mum diameter particles can rid the tips of contaminating particles completely and recover 90% of the initial adhesive strength. This finding is significant because it is the first demonstration of adhesion recovery through dry self-cleaning by contact to a non-sticky cleaning substrate. The degree to which adhesion is recovered is superior to any conventional adhesive and is nearly identical to the gecko itself. This thesis presents a study of controlling adhesion in gecko-inspired adhesives. This control is achieved by maximizing or minimizing attachment strength on demand by simple mechanical loading, and enables robotic manipulation tasks and the recovery of adhesion after contamination. Looking forward, we can predict what is possible for gecko-inspired adhesives if the discoveries in this thesis are implemented, and if other shortcomings in the field are resolved. Looking at the applications already under development, it seems clear that medical adhesives have great potential, and climbing robots might achieve significant utility. In consumer products, gecko-adhesives might replace VelcroRTMand zippers in clothing, and might become a critical component in sports gear, e.g. soccer goal keeper and rock climber gloves. The reversible, controllable nature of the adhesion, as well as its incredible bonding strength, suggests more impressive possibilities for gecko-inspired adhesives: perhaps it might act as a fastener for temporary or emergency construction. We might yet see rolls of single-sided and double-sided gecko-tape sold in hardware stores, not as a replacement for duct tape, but as a replacement for nails, staples and screws. (Abstract shortened by UMI.)

75 FR 26889 - Airworthiness Directives; Arrow Falcon Exporters, Inc. (previously Utah State University) et al...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-13

... the forward tip weight retention block (tip block) or aft tip closure (tip closure), loss of the blade...) forward tip weight retention block (tip block) and the aft tip closure (tip closure) for adhesive bond... prevent loss of a tip block or tip closure, loss of a blade, and subsequent loss of control of the...

Mitigating operating room fires: development of a carbon dioxide fire prevention device.

PubMed

Culp, William C; Kimbrough, Bradly A; Luna, Sarah; Maguddayao, Aris J

2014-04-01

Operating room fires are sentinel events that present a real danger to surgical patients and occur at least as frequently as wrong-sided surgery. For fire to occur, the 3 points of the fire triad must be present: an oxidizer, an ignition source, and fuel source. The electrosurgical unit (ESU) pencil triggers most operating room fires. Carbon dioxide (CO2) is a gas that prevents ignition and suppresses fire by displacing oxygen. We hypothesize that a device can be created to reduce operating room fires by generating a cone of CO2 around the ESU pencil tip. One such device was created by fabricating a divergent nozzle and connecting it to a CO2 source. This device was then placed over the ESU pencil, allowing the tip to be encased in a cone of CO2 gas. The device was then tested in 21%, 50%, and 100% oxygen environments. The ESU was activated at 50 W cut mode while placing the ESU pencil tip on a laparotomy sponge resting on an aluminum test plate for up to 30 seconds or until the sponge ignited. High-speed videography was used to identify time of ignition. Each test was performed in each oxygen environment 5 times with the device activated (CO2 flow 8 L/min) and with the device deactivated (no CO2 flow-control). In addition, 3-dimensional spatial mapping of CO2 concentrations was performed with a CO2 sampling device. The median ± SD [range] ignition time of the control group in 21% oxygen was 2.9 s ± 0.44 [2.3-3.0], in 50% oxygen 0.58 s ± 0.12 [0.47-0.73], and in 100% oxygen 0.48 s ± 0.50 [0.03-1.27]. Fires were ignited with each control trial (15/15); no fires ignited when the device was used (0/15, P < 0.0001). The CO2 concentration at the end of the ESU pencil tip was 95%, while the average CO2 concentration 1 to 1.4 cm away from the pencil tip on the bottom plane was 64%. In conclusion, an operating room fire prevention device can be created by using a divergent nozzle design through which CO2 passes, creating a cone of fire suppressant. This device as demonstrated in a flammability model effectively reduced the risk of fire. CO2 3-dimensional spatial mapping suggests effective fire reduction at least 1 cm away from the tip of the ESU pencil at 8 L/min CO2 flow. Future testing should determine optimum CO2 flow rates and ideal nozzle shapes. Use of this device may substantially reduce the risk of patient injury due to operating room fires.

Orbital experiment ``Gravisensor'': phototropic reactions of the moss Physcomitrella patens to different types of LED lighting.

NASA Astrophysics Data System (ADS)

Nikitin, Vladimir; Berkovich, Yuliy A.; Skripnikov, Alexander; Zyablova, Natalya; Mukhoyan, Makar; Emelianov, Grigory

The experiment was conducted on Russian Biological Satelite Bion-M #1 19.04-19.05 2013. Five transparent plastic cultural flasks were placed in five light isolated sections of Biocont-B2 cylindrical container with inner diameter of 120 mm and height of 230 mm. In four sections the flasks could be illuminated by top or side LED with wavelength of 458 nm, 630 nm, 730 nm, and white (color temperature 5000° K, peaks 453, 559 nm). Photon flux in each variant was 15 umol/(m2c). In the fifth section the flask with the shoots was in conditions of constant dark. Each section was equipped with its own video camera module. Cameras, video recorder and lighting were managed by micro controller. 12 days before launch, 5 tips of the moss shoots were explanted at each of the five flasks on the agar medium with nutrient components and were cultivated under white fluorescent lamps at 12 hour photo period till the launch. After entering the orbit and during next 14 days of flight top LEDs were turned on above the flasks. Then for the following 14 days of flight the side LEDs of similar wavelength were turned on. The moss gametophores were cultivated at 12-h photoperiod. During the experiment on an hourly basis a video recording of the moss was performed. Similar equipment was used for ground control. After the experiment video files were used to produce separate time-lapse films for each flask using AviSynth program. In flight the shoots demonstrated the maximum growth speed with far red lighting and slower speed with white lighting. With blue and red lighting after switching to side light stimuli the growth of shoots almost stopped. In the dark the shoots continued to grow until the 13 day after launch of the satellite, then their growth stopped. In ground control the relation of growth rate with various LEDs remained basically the same, with the exception of side blue lighting, where the shoots demonstrated considerable vertical growth. In flight the angle of inclination towards the light source was maximal (about 90º) with white lighting, and somewhat smaller with 730 nm. Under red and blue light the angle of phototropic inclination was difficult to measure due to poor growth of the shoots.In ground control the growth rate under blue light was several times higher, than in flight and final degree of inclination of the shoot tip came to about 10º. In ground control under side red lighting the growth was weak, while demonstrating a pronounced phototropic bend of 90º. In ground control in the dark a vertical growth of one shoot was observed with the rate somewhat larger, than in flight variant. Data on the dynamics of inclination of experimental and control plants are presented. The acquired data will be used to analyse the mechanisms of phototropic growth changes of moss shoots.

Diffusing, side-firing, and radial delivery laser balloon catheters for creating subsurface thermal lesions in tissue

NASA Astrophysics Data System (ADS)

Chang, Chun-Hung; Fried, Nathaniel M.

2016-02-01

Infrared lasers have been used in combination with applied cooling methods to preserve superficial skin layers during cosmetic surgery. Similarly, combined laser irradiation and tissue cooling may also allow development of minimally invasive laser therapies beyond dermatology. This study compares diffusing, side-firing, and radial delivery laser balloon catheter designs for creation of subsurface lesions in tissue, ex vivo, using a near-IR laser and applied contact cooling. An Ytterbium fiber laser with 1075 nm wavelength delivered energy through custom built 18 Fr (6-mm-OD) balloon catheters incorporating either 10-mm-long diffusing fiber tip, 90 degree side-firing fiber, or radial delivery cone mirror, through a central lumen. A chilled solution was flowed through a separate lumen into 9-mm-diameter balloon to keep probe cooled at 7°C. Porcine liver tissue samples were used as preliminary tissue model for immediate observation of thermal lesion creation. The diffusing fiber produced subsurface thermal lesions measuring 49.3 +/- 10.0 mm2 and preserved 0.8 +/- 0.1 mm of surface tissue. The side-firing fiber produced subsurface thermal lesions of 2.4 +/- 0.9 mm2 diameter and preserved 0.5 +/- 0.1 mm of surface tissue. The radial delivery probe assembly failed to produce subsurface thermal lesions, presumably due to the small effective spot diameter at the tissue surface, which limited optical penetration depth. Optimal laser power and irradiation time measured 15 W and 100 s for diffusing fiber and 1.4 W and 20 s, for side-firing fiber, respectively. Diffusing and side-firing laser balloon catheter designs provided subsurface thermal lesions in tissue. However, the divergent laser beam in both designs limited the ability to preserve a thicker layer of tissue surface. Further optimization of laser and cooling parameters may be necessary to preserve thicker surface tissue layers.

Influence of blade tip rounding on tip leakage vortex cavitation of axial flow pump

NASA Astrophysics Data System (ADS)

Wu, S. Q.; Shi, W. D.; Zhang, D. S.; Yao, J.; Cheng, C.

2013-12-01

Tip leakage flow in axial flow pumps is mainly caused by the tip clearance, which is the main cause of tip leakage vortex cavitation and blade tip cavitation erosion. In order to improve tip clearance flow and reduce TLV cavitation, four schemes were adopted to the round blade tip. These are: no tip rounding, one time tip clearance tip rounding, two times tip clearance tip rounding, four times tip clearance tip rounding. Using SST k-ω turbulence model and Zwart cavitation model in CFX software, this simulation obtained four kinds of inner flow field results. The numerical results indicated that with the increase of r*, NPSHc gradually increased and the cavitation performance reduced. However, corner vortex was eliminated so that cavitation in gap was restrained. But TLV vorticity increased and cavitation's range here had a little expansion. Combined with the research of this paper and the different analyses of four schemes, we recommend adopting the two times of the tip clearance rounding.

Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy

PubMed Central

Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola

2016-01-01

Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique. PMID:27426442

Photonic jet μ-etching: from static to dynamic process

NASA Astrophysics Data System (ADS)

Abdurrochman, A.; Lecler, S.; Zelgowski, J.; Mermet, F.; Fontaine, J.; Tumbelaka, B. Y.

2017-05-01

Photonic jet etching is a direct-laser etching method applying photonic jet phenomenon to concentrate the laser beam onto the proceeded material. We call photonic jet the phenomenon of the localized sub-wavelength propagative beam generated at the shadow-side surfaces of micro-scale dielectric cylinders or spheres, when they are illuminated by an electromagnetic plane-wave or laser beam. This concentration has made possible the laser to yield sub-μ etching marks, despite the laser was a near-infrared with nano-second pulses sources. We will present these achievements from the beginning when some spherical glasses were used for static etching to dynamic etching using an optical fiber with a semi-elliptical tip.

Noise of the SR-3 propeller model at 2 deg and 4 deg angle of attack

NASA Technical Reports Server (NTRS)

Dittmar, J. H.; Jeracki, R. J.

1981-01-01

The noise effect of operating supersonic tip speed propellers at angle of attack with respect to the incoming flow was determined. Increases in the maximum blade passage noise were observed for the propeller operating at angle of attack. The noise increase was not symmetrical with one wall of the wind tunnel having significantly more noise increase than the other wall. This was apparently the result of the rotational direction of the propeller. The lack of symmetry of the noise at angle of attack to the use of oppositely rotating propellers on opposite sides of an airplane fuselage as a way of minimizing the noise due to operation at angle of attack.

Reconciling STS and ARPES data for the correlated superconductor LiFeAs

NASA Astrophysics Data System (ADS)

Hong, Jongbae; Abergel, David

The inconsistency between the density of states revealed by scanning tunneling spectroscopy (STS) and that given by angle-resolved photoemission spectroscopy (ARPES) is a substantial problem for understanding the nature of strongly correlated superconductors such as Fe-based LiFeAs and the cuprates. We reveal that the two side peaks commonly appearing in both pnictide and cuprate superconductors are the result of the non-equilibrium behavior associated with singlet cotunneling from the tip to the strongly correlated sample. We accurately reproduce the STS line shape of the Fe-based LiFeAs using a sample density of states which coincides with ARPES data, thereby producing a unified description for these materials.

Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy.

PubMed

Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola

2016-07-18

Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique.

Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy

NASA Astrophysics Data System (ADS)

Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola

2016-07-01

Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique.

Quantification of asymmetric microtubule nucleation at sub-cellular structures

PubMed Central

Zhu, Xiaodong; Kaverina, Irina

2012-01-01

Cell polarization is important for multiple physiological processes. In polarized cells, microtubules (MTs) are organized into a spatially polarized array. Generally, in non-differentiated cells, it is assumed that MTs are symmetrically nucleated exclusively from centrosome (microtubule organizing center, MTOC) and then reorganized into the asymmetric array. We have recently identified the Golgi complex as an additional MTOC that asymmetrically nucleates MTs toward one side of the cell. Methods used for alternative MTOC identification include microtubule re-growth after complete drug-induced depolymerization and tracking of growing microtubules using fluorescence labeled MT +TIP binding proteins in living cells. These approaches can be used for quantification of MT nucleation sites at diverse sub-cellular structures. PMID:21773933

Multiple piece turbine blade

DOEpatents

Kimmel, Keith D [Jupiter, FL

2012-05-29

A turbine rotor blade with a spar and shell construction, the spar including an internal cooling supply channel extending from an inlet end on a root section and ending near the tip end, and a plurality of external cooling channels formed on both side of the spar, where a middle external cooling channel is connected to the internal cooling supply channels through a row of holes located at a middle section of the channels. The spar and the shell are held together by hooks that define serpentine flow passages for the cooling air and include an upper serpentine flow circuit and a lower serpentine flow circuit. the serpentine flow circuits all discharge into a leading edge passage or a trailing edge passage.

Effects of Alternate Leading Edge Cutback on the Space Shuttle Main Engine Low Pressure Fuel Pump

NASA Technical Reports Server (NTRS)

Mulder, Andrew; Skelley, Stephen

2016-01-01

A higher order cavitation oscillation observed in the SSME low pressure fuel pump has been eliminated in water flow testing of a modified subscale replica of the inducer. The low pressure pump was modified by removing the outboard sections of two opposing blades of the four-bladed inducer, blending the "cutback" regions into the blades at the leading edge and tip, and removing material on the suction sides to decrease the exposed leading edge thickness. The leading edge tips of the cutback blades were moved approximately 25 degrees from their previous locations, thereby increasing one blade to blade spacing, decreasing the second, while simultaneously moving the cutback tips downstream. The test was conducted in MSFC's inducer test loop at scaled operating conditions in degassed and filtered water. In addition to eliminating HOC across the entire scaled operating regime, rotating cavitation was suppressed while the range of both alternate blade and asymmetric cavitation were increased. These latter phenomena, and more significantly, the shifts between these cavitation modes also resulted in significant changes to the head coefficient at low cavitation numbers. Reverse flow was detected at a slightly larger flow coefficient with the cutback inducer and suction capability was reduced by approximately 1 velocity head at and above approximately 90% of the reference flow coefficient. These performance changes along with more intense reverse flow are consistent with poor flow area management and increased incidence in the cutback region. Although the test demonstrated that the inducer modification was successful at eliminating the higher order cavitation across the entire scaled operating regime, different, previously unobserved, cavitation oscillations were introduced and significant performance penalties were imposed.

Polarization-resolved micro-photoluminescence investigation of InGaN/GaN core-shell microrods

NASA Astrophysics Data System (ADS)

Mounir, Christian; Schimpke, Tilman; Rossbach, Georg; Avramescu, Adrian; Strassburg, Martin; Schwarz, Ulrich T.

2017-01-01

We investigate the optical emission properties of the active InGaN shell of high aspect-ratio InGaN/GaN core-shell microrods (μRods) by confocal quasi-resonant polarization-resolved and excitation density dependent micro-photoluminescence (μPL). The active shell, multiple thin InGaN/GaN quantum wells (MQWs), was deposited on GaN μRods selectively grown by metal organic vapor phase epitaxy on patterned SiO2/n-GaN/sapphire template. High spatial resolution mappings reveal a very homogeneous emission intensity along the whole μRods including the tip despite a red-shift of 30 nm from the base to the tip along the 8.6 μm-long m-plane sidewalls. Looking at the Fabry-Perot interference fringes superimposed on the μPL spectra, we get structural information on the μRods. A high degree of linear polarization (DLP) of 0.6-0.66 is measured on the lower half of the m-plane side facets with a slight decrease toward the tip. We observe the typical drop of the DLP with an excitation density caused by degenerate filling of valence bands (Fermi regime). Local internal quantum efficiencies (IQEs) of 55 ±11 % up to 73 ±7 % are estimated on the m-plane facet from measurements at low temperature. Finally, simultaneously fitting the DLP and IQE as a function of the excitation density, we determine the carrier density inside the active region and the recombination rate coefficients of the m-plane MQWs. We show that phase-space filling and the background carrier density have to be included in the recombination rate model.

Biochemical and Immunocytological Characterizations of Arabidopsis Pollen Tube Cell Wall1[C][W][OA

PubMed Central

Dardelle, Flavien; Lehner, Arnaud; Ramdani, Yasmina; Bardor, Muriel; Lerouge, Patrice; Driouich, Azeddine; Mollet, Jean-Claude

2010-01-01

During plant sexual reproduction, pollen germination and tube growth require development under tight spatial and temporal control for the proper delivery of the sperm cells to the ovules. Pollen tubes are fast growing tip-polarized cells able to perceive multiple guiding signals emitted by the female organ. Adhesion of pollen tubes via cell wall molecules may be part of the battery of signals. In order to study these processes, we investigated the cell wall characteristics of in vitro-grown Arabidopsis (Arabidopsis thaliana) pollen tubes using a combination of immunocytochemical and biochemical techniques. Results showed a well-defined localization of cell wall epitopes. Low esterified homogalacturonan epitopes were found mostly in the pollen tube wall back from the tip. Xyloglucan and arabinan from rhamnogalacturonan I epitopes were detected along the entire tube within the two wall layers and the outer wall layer, respectively. In contrast, highly esterified homogalacturonan and arabinogalactan protein epitopes were found associated predominantly with the tip region. Chemical analysis of the pollen tube cell wall revealed an important content of arabinosyl residues (43%) originating mostly from (1→5)-α-l-arabinan, the side chains of rhamnogalacturonan I. Finally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of endo-glucanase-sensitive xyloglucan showed mass spectra with two dominant oligosaccharides (XLXG/XXLG and XXFG), both being mono O-acetylated, and accounting for over 68% of the total ion signals. These findings demonstrate that the Arabidopsis pollen tube wall has its own characteristics compared with other cell types in the Arabidopsis sporophyte. These structural features are discussed in terms of pollen tube cell wall biosynthesis and growth dynamics. PMID:20547702

Biochemical and immunocytological characterizations of Arabidopsis pollen tube cell wall.

PubMed

Dardelle, Flavien; Lehner, Arnaud; Ramdani, Yasmina; Bardor, Muriel; Lerouge, Patrice; Driouich, Azeddine; Mollet, Jean-Claude

2010-08-01

During plant sexual reproduction, pollen germination and tube growth require development under tight spatial and temporal control for the proper delivery of the sperm cells to the ovules. Pollen tubes are fast growing tip-polarized cells able to perceive multiple guiding signals emitted by the female organ. Adhesion of pollen tubes via cell wall molecules may be part of the battery of signals. In order to study these processes, we investigated the cell wall characteristics of in vitro-grown Arabidopsis (Arabidopsis thaliana) pollen tubes using a combination of immunocytochemical and biochemical techniques. Results showed a well-defined localization of cell wall epitopes. Low esterified homogalacturonan epitopes were found mostly in the pollen tube wall back from the tip. Xyloglucan and arabinan from rhamnogalacturonan I epitopes were detected along the entire tube within the two wall layers and the outer wall layer, respectively. In contrast, highly esterified homogalacturonan and arabinogalactan protein epitopes were found associated predominantly with the tip region. Chemical analysis of the pollen tube cell wall revealed an important content of arabinosyl residues (43%) originating mostly from (1-->5)-alpha-L-arabinan, the side chains of rhamnogalacturonan I. Finally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of endo-glucanase-sensitive xyloglucan showed mass spectra with two dominant oligosaccharides (XLXG/XXLG and XXFG), both being mono O-acetylated, and accounting for over 68% of the total ion signals. These findings demonstrate that the Arabidopsis pollen tube wall has its own characteristics compared with other cell types in the Arabidopsis sporophyte. These structural features are discussed in terms of pollen tube cell wall biosynthesis and growth dynamics.

En-masse retraction with a preformed nickel-titanium and stainless steel archwire assembly and temporary skeletal anchorage devices without posterior bonding

PubMed Central

Jee, Jeong-Hyun; Ahn, Hyo-Won; Seo, Kyung-Won; Kook, Yoon-Ah; Chung, Kyu-Rhim; Nelson, Gerald

2014-01-01

Objective To evaluate the therapeutic effects of a preformed assembly of nickel-titanium (NiTi) and stainless steel (SS) archwires (preformed C-wire) combined with temporary skeletal anchorage devices (TSADs) as the sole source of anchorage and to compare these effects with those of a SS version of C-wire (conventional C-wire) for en-masse retraction. Methods Thirty-one adult female patients with skeletal Class I or II dentoalveolar protrusion, mild-to-moderate anterior crowding (3.0-6.0 mm), and stable Class I posterior occlusion were divided into conventional (n = 15) and preformed (n = 16) C-wire groups. All subjects underwent first premolar extractions and en-masse retraction with pre-adjusted edgewise anterior brackets, the assigned C-wire, and maxillary C-tubes or C-implants; bonded mesh-tube appliances were used in the mandibular dentition. Differences in pretreatment and post-retraction measurements of skeletal, dental, and soft-tissue cephalometric variables were statistically analyzed. Results Both groups showed full retraction of the maxillary anterior teeth by controlled tipping and space closure without altered posterior occlusion. However, the preformed C-wire group had a shorter retraction period (by 3.2 months). Furthermore, the maxillary molars in this group showed no significant mesialization, mesial tipping, or extrusion; some mesialization and mesial tipping occurred in the conventional C-wire group. Conclusions Preformed C-wires combined with maxillary TSADs enable simultaneous leveling and space closure from the beginning of the treatment without maxillary posterior bonding. This allows for faster treatment of dentoalveolar protrusion without unwanted side effects, when compared with conventional C-wire, evidencing its clinical expediency. PMID:25309863

Computer-aided analysis of cutting processes for brittle materials

NASA Astrophysics Data System (ADS)

Ogorodnikov, A. I.; Tikhonov, I. N.

2017-12-01

This paper is focused on 3D computer simulation of cutting processes for brittle materials and silicon wafers. Computer-aided analysis of wafer scribing and dicing is carried out with the use of the ANSYS CAE (computer-aided engineering) software, and a parametric model of the processes is created by means of the internal ANSYS APDL programming language. Different types of tool tip geometry are analyzed to obtain internal stresses, such as a four-sided pyramid with an included angle of 120° and a tool inclination angle to the normal axis of 15°. The quality of the workpieces after cutting is studied by optical microscopy to verify the FE (finite-element) model. The disruption of the material structure during scribing occurs near the scratch and propagates into the wafer or over its surface at a short range. The deformation area along the scratch looks like a ragged band, but the stress width is rather low. The theory of cutting brittle semiconductor and optical materials is developed on the basis of the advanced theory of metal turning. The fall of stress intensity along the normal on the way from the tip point to the scribe line can be predicted using the developed theory and with the verified FE model. The crystal quality and dimensions of defects are determined by the mechanics of scratching, which depends on the shape of the diamond tip, the scratching direction, the velocity of the cutting tool and applied force loads. The disunity is a rate-sensitive process, and it depends on the cutting thickness. The application of numerical techniques, such as FE analysis, to cutting problems enhances understanding and promotes the further development of existing machining technologies.

Patterns and perspectives in applied fracture mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkle, J.G.

1994-12-31

This lecture begins with a overview of applied fracture mechanics pertinent to safety of pressure vessels. It then progresses to a chronological panorama of experimental and analytical results. To be useful and dependable in safety analysis of real structures, new analysis developments must be physically realistic, which means that they must accurately describe physical cause and effect. Consequently, before mathematical modeling can begin, cause and effect must be established from experimental data. This can be difficult and time consuming, but worth the effort. Accordingly, the theme of this paper is that the search for patterns is constant and vital. Thismore » theme is illustrated by the development of small, single-specimen, fracture toughness testing techniques. It is also illustrated by the development, based on two different published large-strain, elastic-plastic, three-dimensional finite-element analyses, of a hypothesis concerning three-dimensional loss of constraint. When a generalization of Irwin`s thickness-normalized plastic-zone parameter, reaches a value close to 2{pi}, the through-thickness contraction strain at the apex of the near-tip logarithmic-spiral slip-line region becomes the dominant negative strain accommodating crack opening. Because slip lines passing from the midplane to the stress-free side surfaces do not have to curve, once these slip lines are established, stresses near the crack tip are only elevated by strain hardening and constraint becomes significantly relaxed. This hypothesis, based on published three-dimensional elastic-plastic analyses, provides a potentially valuable means for gaining additional insight into constraint effects on fracture toughness by considering the roles played by the plastic strains as well as the stresses that develop near a crack tip.« less

NPH3- and PGP-like genes are exclusively expressed in the apical tip region essential for blue-light perception and lateral auxin transport in maize coleoptiles.

PubMed

Matsuda, Satomi; Kajizuka, Tomomi; Kadota, Akeo; Nishimura, Takeshi; Koshiba, Tomokazu

2011-06-01

Phototropic curvature results from differential growth on two sides of the elongating shoot, which is explained by asymmetrical indole-3-acetic acid (IAA) distribution. Using 2 cm maize coleoptile segments, 1st positive phototropic curvature was confirmed here after 8 s irradiation with unilateral blue light (0.33 μmol m(-2) s(-1)). IAA was redistributed asymmetrically by approximately 20 min after photo-stimulation. This asymmetric distribution was initiated in the top 0-3 mm region and was then transmitted to lower regions. Application of the IAA transport inhibitor, 1-N-naphthylphthalamic acid (NPA), to the top 2 mm region completely inhibited phototropic curvature, even when auxin was simultaneously applied below the NPA-treated zone. Thus, lateral IAA movement occurred only within the top 0-3 mm region after photo-stimulation. Localized irradiation experiments indicated that the photo-stimulus was perceived in the apical 2 mm region. The results suggest that this region harbours key components responsible for photo-sensing and lateral IAA transport. In the present study, it was found that the NPH3- and PGP-like genes were exclusively expressed in the 0-2 mm region of the tip, whereas PHOT1 and ZmPIN1a, b, and c were expressed relatively evenly along the coleoptile, and ZmAUX1, ZMK1, and ZmSAURE2 were strongly expressed in the elongation zone. These results suggest that the NPH3-like and PGP-like gene products have a key role in photo-signal transduction and regulation of the direction of auxin transport after blue light perception by phot1 at the very tip region of maize coleoptiles.

An experimental investigation of free-tip response to a jet

NASA Technical Reports Server (NTRS)

Young, L. A.

1986-01-01

The aerodynamic response of passively oscillating tips appended to a model helicopter rotor was investigated during a whirl test. Tip responsiveness was found to meet free-tip rotor requirements. Experimental and analytical estimates of the free-tip aerodynamic spring, mechanical spring, and aerodynamic damping were calculated and compared. The free tips were analytically demonstrated to be operating outside the tip resonant response region at full-scale tip speeds. Further, tip resonance was shown to be independent of tip speed, given the assumption that the tip forcing frequency is linearly dependent upon the rotor rotational speed.

Feasibility of Using Ultrasonography to Establish Relationships Among Sacral Base Position, Sacral Sulcus Depth, Body Mass Index, and Sex.

PubMed

Lockwood, Michael D; Kondrashova, Tatyana; Johnson, Jane C

2015-11-01

Identifying relationships among anatomical structures is key in diagnosing somatic dysfunction. Ultrasonography can be used to visualize anatomical structures, identify sacroiliac landmarks, and validate anatomical findings and measurements in relation to somatic dysfunction. As part of the osteopathic manipulative medicine course at A.T. Still University-Kirksville College of Osteopathic Medicine, first-year students are trained to use ultrasonography to establish relationships among musculoskeletal structures. To determine the ability of first-year osteopathic medical students to establish sacral base position (SBP) and sacral sulcus depth (SSD) using ultrasonography and to identify the relationship of SBP and SSD to body mass index (BMI) and sex. Students used ultrasonography to obtain the distance between the skin and the sacral base (the SBP) and the distance between the skin and the tip of the posterior superior iliac spine bilaterally. Next, students calculated the SSD (the distance between the tip of the posterior superior iliac spine and the SBP). Data were analyzed with respect to side of the body, BMI, sex, and age. The BMI data were subdivided into normal (18-25 mg/kg) and overweight (25-30 mg/kg) groups. Ultrasound images of 211 students were included in the study. The SBP was not significantly different between the left and right sides (36.5 mm vs 36.5 mm; P=.95) but was significantly different between normal and overweight BMI categories (33.0 mm vs 40.0 mm; P<.001) and between men and women (34.1 mm vs 39.0 mm; P<.001). The SSD was not significantly different between left and right sides (18.9 mm vs 19.8 mm; P=.08), normal and overweight BMI categories (18.9 mm vs 19.7 mm, P=.21), or men and women (19.7 mm vs 19.0 mm; P=.24). No significant relationship was identified between age and SBP (P=.46) or SSD (P=.39); however, the age range was narrow (21-33 years). The study yielded repeatable and reproducible results when establishing SBP and SSD using ultrasonography. The statistically significant relationship between SBP and higher BMI and between SBP and female sex may point to more soft tissue overlaying the sacrum in these groups. Further research is needed on the use of ultrasonography to establish criteria for somatic dysfunction.

A study about the split drag flaps deflections to directional motion of UiTM's blended wing body aircraft based on computational fluid dynamics simulation

NASA Astrophysics Data System (ADS)

Mohamad, Firdaus; Wisnoe, Wirachman; Nasir, Rizal E. M.; Kuntjoro, Wahyu

2012-06-01

This paper discusses on the split drag flaps to the yawing motion of BWB aircraft. This study used split drag flaps instead of vertical tail and rudder with the intention to generate yawing moment. These features are installed near the tips of the wing. Yawing moment is generated by the combination of side and drag forces which are produced upon the split drag flaps deflection. This study is carried out using Computational Fluid Dynamics (CFD) approach and applied to low subsonic speed (0.1 Mach number) with various sideslip angles (β) and total flaps deflections (δT). For this research, the split drag flaps deflections are varied up to ±30°. Data in terms of dimensionless coefficient such as drag coefficient (CD), side coefficient (CS) and yawing moment coefficient (Cn) were used to observe the effect of the split drag flaps. From the simulation results, these split drag flaps are proven to be effective from ±15° deflections or 30° total deflections.

Room-temperature fracture in V-(4-5)Cr-(4-5)Ti tensile specimens irradiated in Fusion-1 BOR-60 experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gazda, J.; Meshii, M.; Tsai, H.

Specimens of V-(4-5)Cr-(4-5)Ti alloys were irradiated to {approx}18 dpa at 320 C in the Fusion-1 capsule inserted into the BOR-60 reactor. Tensile tests at 23 C indicated dramatic yield strength increase (>300%), lack of work hardening, and minimal (<1%) total elongations. SEM analysis of fracture and side surfaces were conducted to determine reduction in are and the mode of fracture. The reduction of area was negligible. All but one specimen failed by a combination of ductile shear deformation and cleavage crack growth. Transgranular cleavage cracks were initiated by stress concentrations at the tips of the shear bands. In side-view observations,more » evidence was found of slip bands typically associated with dislocation channeling. No differences due to pre-irradiation heat treatment and heat-to-heat composition variations were detected. The only deviation from this behavior was found in V-4Cr-4Ti-B alloy, which failed in the grip portion by complete cleavage cracking.« less

Wake Geometry Effects on Rotor Blade-Vortex Interaction Noise Directivity

NASA Technical Reports Server (NTRS)

Martin, R. M.; Marcolini, Michael A.; Splettstoesser, W. R.; Schultz, K.-J.

1990-01-01

Acoustic measurements from a model rotor wind tunnel test are presented which show that the directionality of rotor blade vortex interaction (BVI) noise is strongly dependent on the rotor advance ratio and disk attitude. A rotor free wake analysis is used to show that the general locus of interactions on the rotor disk is also strongly dependent on advance ratio and disk attitude. A comparison of the changing directionality of the BVI noise with changes in the interaction locations shows that the strongest noise radiation occurs in the direction of motion normal to the blade span at the time of interaction, for both advancing and retreating side BVI. For advancing side interactions, the BVI radiation angle down from the tip-path plane appears relatively insensitive to rotor operating condition and is typically between 40 and 55 deg below the disk. However, the azimuthal radiation direction shows a clear trend with descent speed, moving towards the right of the flight path with increasing descent speed. The movement of the strongest radiation direction is attributed to the movement of the interaction locations on the rotor disk with increasing descent speed.

On the aeroacoustic and flow structures developed on a flat plate with a serrated sawtooth trailing edge

NASA Astrophysics Data System (ADS)

Chong, Tze Pei; Vathylakis, Alexandros

2015-10-01

Results of an experimental study on turbulent flow over a flat plate with a serrated sawtooth trailing edge are presented in this paper. After tripping the boundary layer to become turbulent, the broadband noise sources at the sawtooth serrated trailing edge is studied by several experimental techniques. Broadband noise reduction by the serrated sawtooth trailing edge can be realistically achieved in the flat plate configuration. The variations of wall pressure power spectral density and the spanwise coherence (which relates to the spanwise correlation length) in a sawtooth trailing edge play a minor role in the mechanisms underpinning the reduction of self noise radiation. Conditional-averaging technique was applied in the boundary layer data where a pair of pressure-driven oblique vortical structures near the sawtooth side edges is identified. In the current flat plate configuration, the interaction between the vortical structures and the local turbulent boundary layer results in a redistribution of the momentum transport and turbulent shear stress near the sawtooth side edges as well as the sawtooth tip, thus affecting the efficiency of self noise radiation.

Melanism is related to behavioural lateralization in nestling barn owls.

PubMed

Gaillard, Maryline; Scriba, Madeleine F; Roulin, Alexandre

2017-07-01

Behavioural laterality is a commonly observed phenomenon in many species suggesting there might be an advantage of using dominantly one side over the other for certain tasks. Indeed, lateralized individuals were often shown to be more successful in cognitive tasks compared to non-lateralized conspecifics. However, stressed individuals are also often, but not always, more strongly lateralized. Because barn owl (Tyto alba) females displaying larger black spots on the tip of their ventral feathers produce offspring that are more resistant to a variety of environmental stressful factors, we examined whether laterality is associated with melanin-based coloration. We recorded whether nestlings use more often the right or left foot to scratch their body and whether they preen more often one side of the body or the other using their bills. We found that the strength of lateralization of preening and scratching was less pronounced in individuals born from heavily spotted mothers. This result might be explained by plumage-related variation in the ability to resist stressful rearing conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

[Shaping ability of two nickel-titanium rotary systems in simulated S-shaped canals].

PubMed

Luo, Hong-xia; Huang, Ding-ming; Zhang, Fu-hua; Tan, Hong; Zhou, Xue-dong

2008-01-01

To evaluate the shaping ability of two nickel-titanium rotary systems (ProTaper and Hero642) in simulated S-shaped canals. Thirty simulated S-shaped canals were randomly divided into three groups and prepared by ProTaper, Hero642, ProTaper combined with Hero642 respectively. All the canals were scanned before and after instrumentation, and the amount of material removed in the inner and outer wall and the canal width after instrumentation were measured with a computer image analysis program. There was significant difference in the amount of material removed at the inner side of apical curvature and outer side of apex between ProTaper combined with Hero642 and ProTaper files (P < 0.05) at the same tip size. The inner and outer wall of the canals were evenly prepared by ProTaper combined with Hero642, and the taper of canals were better than those prepared by Hero642. ProTaper combined with Hero 642 had better shaping ability to maintain the original shape and could create good taper canals in the simulated S-shaped canal model.

Receptivity of Hypersonic Boundary Layers to Acoustic and Vortical Disturbances

NASA Technical Reports Server (NTRS)

Balakamar, P.; Kegerise, Michael A.

2011-01-01

Boundary layer receptivity to two-dimensional acoustic disturbances at different incidence angles and to vortical disturbances is investigated by solving the Navier-Stokes equations for Mach 6 flow over a 7deg half-angle sharp-tipped wedge and a cone. Higher order spatial and temporal schemes are employed to obtain the solution. The results show that the instability waves are generated in the leading edge region and that the boundary layer is much more receptive to slow acoustic waves as compared to the fast waves. It is found that the receptivity of the boundary layer on the windward side (with respect to the acoustic forcing) decreases when the incidence angle is increased from 0 to 30 degrees. However, the receptivity coefficient for the leeward side is found to vary relatively weakly with the incidence angle. The maximum receptivity is obtained when the wave incident angle is about 20 degrees. Vortical disturbances also generate unstable second modes, however the receptivity coefficients are smaller than that for the acoustic waves. Vortical disturbances first generate the fast acoustic modes and they switch to the slow mode near the continuous spectrum.

The sensory equipment of a spider - A morphological survey of different types of sensillum in both sexes of Argiope bruennichi (Araneae, Araneidae).

PubMed

Ganske, Anne-Sarah; Uhl, Gabriele

2018-03-01

Spiders show a wide range of sensory capabilities as evidenced by behavioural observations. Accordingly, spiders possess diverse sensory structures like mechano-, hygro-, thermo- or chemoreceptive sensilla. As to chemoreceptive structures, only trichoid tip-pore sensilla were found so far that were tested for gustation. That spiders are also able to receive airborne signals is corroborated by numerous behavioural experiments but the responsible structures have not been determined yet. Here, we provide sensilla distribution maps of pedipalps and walking legs of both sexes of the wasp spider Argiope bruennichi whose biology and mating system is well explored. By means of scanning electron microscopy, we scrutinized whether there is in fact only one type of trichoid pore sensillum and if so, if there are deviations in the outer structure of the tip-pore sensilla depending on their position on the body. We also describe the external structure and distribution of slit sense organs, trichobothria and tarsal organs. Our study shows that all four sensillum types occur on pedipalps and walking legs of both sexes. As to chemosensory organs, only tip-pore sensilla were found, suggesting that this sensillum type is used for both gustation and olfaction. The highest numbers of tip-pore sensilla were observed on metatarsi and tarsi of the first two walking legs. Mechanosensitive slit sense organs occur as single slit sensilla in rows along all podomers or as lyriform organs next to the joints. The mechanosensitive trichobothria occur on the basal part of tibiae and metatarsi. Tarsal organs occur on the dorsal side of all tarsi and the male cymbium. The distribution maps of the sensilla are the starting point for further exploration of internal, morphological differences of the sensilla from different regions on the body. Cryptic anatomical differences might be linked to functional differences that can be explored in combination with electrophysiological analyses. Consequently, the maps will help to elucidate the sensory world of spiders. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bi-directional vibration control of offshore wind turbines using a 3D pendulum tuned mass damper

NASA Astrophysics Data System (ADS)

Sun, C.; Jahangiri, V.

2018-05-01

Offshore wind turbines suffer from excessive bi-directional vibrations due to wind-wave misalignment and vortex induced vibrations. However, most of existing research focus on unidirectional vibration attenuation which is inadequate for real applications. The present paper proposes a three dimensional pendulum tuned mass damper (3d-PTMD) to mitigate the tower and nacelle dynamic response in the fore-aft and side-side directions. An analytical model of the wind turbine coupled with the 3d-PTMD is established wherein the interaction between the blades, the tower and the 3d-PTMD is modeled. Aerodynamic loading is computed using the Blade Element Momentum method where the Prandtls tip loss factor and the Glauert correction are considered. JONSWAP spectrum is adopted to generate wave data. Wave loading is computed using Morisons equation in collaboration with the strip theory. Via a numerical search approach, the design formula of the 3d-PTMD is obtained and examined on a National Renewable Energy Lab (NREL) monopile 5 MW baseline wind turbine model under misaligned wind, wave and seismic loading. Dual linear tuned mass dampers (TMDs) deployed in the fore-aft and side-side directions are utilized for comparison. It is found that the 3d-PTMD with a mass ratio of 2 % can improve the mitigation of the root mean square and peak response by around 10 % when compared with the dual linear TMDs in controlling the bi-directional vibration of the offshore wind turbines under misaligned wind, wave and seismic loading.

Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing.

PubMed

Baik, Un-Bong; Chun, Youn-Sic; Jung, Min-Ho; Sugawara, Junji

2012-06-01

In a young woman, aged 18 years 8 months, who had an anterior open bite and anterior spacing, the right and left mandibular first molar extraction spaces were closed by protraction of the second and third molars without reciprocal retraction of the incisors and the premolars. The amounts of protraction for the second molars were 12 mm on the right side and 11 mm on the left side. Two miniscrews were inserted into the mesiobuccal side of the edentulous spaces, and 2 more screws were inserted into the anterior sites after removing previous miniscrews. In addition, 4 miniscrews were inserted into the buccal and palatal sides between the first and second maxillary molars to intrude the maxillary posterior teeth, which had extruded into the missing mandibular spaces. Careful biomechanical consideration was used to prevent extrusion of the molars and worsening of the anterior open bite from protraction of the posterior teeth. Ultimately, the anterior open bite was corrected by both intrusion of the maxillary molars and extrusion of the maxillary anterior teeth. Excellent occlusion and correction of the anterior open bite were achieved without tipping, rotation of the posterior teeth, or other problems. The right mandibular third molar, which had been impacted at the beginning of treatment, erupted into the second molar space and functioned properly. At the 1-year follow-up examination, the patient had a slight anterior open bite, but closure of the first molar extraction spaces was well maintained. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Effects of rigid fixation on the growing neurocranium of immature rabbits.

PubMed

Sanus, Galip Zihni; Tanriverdi, Taner; Kacira, Tibet; Jackson, Ian T

2007-03-01

The improved intraoperative long-term skeletal stability achieved with rigid fixation techniques has led to their widespread popularity and application. However, experimental studies have revealed some drawbacks related to metallic implants and long-term results of clinical studies, especially in pediatric patients, has confirmed the results of experimental studies. Our aim in this experimental study using an infant rabbit model is to answer the following question: "Does short-term skeletal stability cause long-term growth inhibition?" Forty, 9-day-old New Zealand white albino rabbits were divided into four groups: 1) experimental, n=6: plated across the right coronal suture and two screws on each side of the left coronal suture; 2) re-operation, n=6: the same materials as group I were placed, and only the plate was removed at the end of 1 month; 3) sham, n=6: sham control with simulated surgery and two screws on each side of the left coronal suture; 4) control, n=2: no operation. The animals were killed 6 months after microplate application, and the skulls were evaluated both grossly and cephalometrically. Gross examination showed that the plates and the screws were covered by bony overgrowth and caused bony irregularity and regional bone degeneration. The parietal bones on the plated sides became striated and lost their concave shape. Cephalometric analysis demonstrated overt mastoid tip deviation toward, or shortening of cranionasal length on, the side with rigid fixation. We conclude from our study that rigid fixation during skeletal development causes growth retardation and should not be used in the growing child.

Characterization of closely related delta-TIP genes encoding aquaporins which are differentially expressed in sunflower roots upon water deprivation through exposure to air.

PubMed

Sarda, X; Tousch, D; Ferrare, K; Cellier, F; Alcon, C; Dupuis, J M; Casse, F; Lamaze, T

1999-05-01

We isolated five sunflower (Helianthus annuus) cDNAs belonging to the TIP (tonoplast intrinsic protein) family. SunRb7 and Sun gammaTIP (partial sequence) are homologous to tobacco TobRb7 and Arabidopsis gamma-TIP, respectively. SunTIP7, 18 and 20 (SunTIPs) are closely related and homologous to Arabidopsis delta-TIP (SunTIP7 and 20 have already been presented in Sarda et al., Plant J. 12 (1997) 1103-1111). As was previously shown for SunTIP7 and 20, expression of SunTIP18 and SunRb7 in Xenopus oocytes caused an increase in osmotic water permeability demonstrating that they are aquaporins. In roots, in situ hybridization revealed that SunTIP7 and 18 mRNAs accumulate in phloem tissues. The expression of TIP-like genes was studied in roots during 24 h water deprivation through exposure to air. During the course of the treatment, each SunTIP gene displayed an individual response: SunTIP7 transcript abundance increased, SunTIP18 decreased whereas that of SunTIP20 was transitorily enhanced. By contrast, SunRb7 and Sun gammaTIP mRNA levels did not fluctuate. Due to the changes in their transcript levels, it is proposed that SUNTIP aquaporins encoded by delta-TIP-like genes play a role in the sunflower response to drought.

Single-Use Energy Sources and Operating Room Time for Laparoscopic Hysterectomy: A Randomized Controlled Trial.

PubMed

Holloran-Schwartz, M Brigid; Gavard, Jeffrey A; Martin, Jared C; Blaskiewicz, Robert J; Yeung, Patrick P

2016-01-01

To compare the intraoperative direct costs of a single-use energy device with reusable energy devices during laparoscopic hysterectomy. A randomized controlled trial (Canadian Task Force Classification I). An academic hospital. Forty-six women who underwent laparoscopic hysterectomy from March 2013 to September 2013. Each patient served as her own control. One side of the uterine attachments was desiccated and transected with the single-use device (Ligasure 5-mm Blunt Tip LF1537 with the Force Triad generator). The other side was desiccated and transected with reusable bipolar forceps (RoBi 5 mm), and transected with monopolar scissors using the same Covidien Force Triad generator. The instrument approach used was randomized to the attending physician who was always on the patient's left side. Resident physicians always operated on the patient's right side and used the converse instruments of the attending physician. Start time was recorded at the utero-ovarian pedicle and end time was recorded after transection of the uterine artery on the same side. Costs included the single-use device; amortized costs of the generator, reusable instruments, and cords; cleaning and packaging of reusable instruments; and disposal of the single-use device. Operating room time was $94.14/min. We estimated that our single use-device cost $630.14 and had a total time savings of 6.7 min per case, or 3.35 min per side, which could justify the expense of the device. The single-use energy device had significant median time savings (-4.7 min per side, p < .001) and total intraoperative direct cost savings ($254.16 per case). A single-use energy device that both desiccates and cuts significantly reduced operating room time to justify its own cost, and it also reduced total intraoperative direct costs during laparoscopic hysterectomy in our institution. Operating room cost per minute varies between institutions and must be considered before generalizing our results. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Taste function assessed by electrogustometry in burning mouth syndrome: a case-control study.

PubMed

Braud, A; Descroix, V; Ungeheuer, M-N; Rougeot, C; Boucher, Y

2017-04-01

Idiopathic burning mouth syndrome (iBMS) is characterized by oral persistent pain without any clinical or biological abnormality. The aim of this study was to evaluate taste function in iBMS subjects and healthy controls. Electrogustometric thresholds (EGMt) were recorded in 21 iBMS patients and 21 paired-matched controls at nine loci of the tongue assessing fungiform and foliate gustatory papillae function. Comparison of EGMt was performed using the nonparametric Wilcoxon signed-rank test. A correlation between EGMt and self-perceived pain intensity assessed using a visual analogic scale (VAS) was analyzed with the Spearman coefficient. The level of significance was fixed at P < 0.05. Mean EGMt were significantly increased with iBMS for right side of the dorsum of the tongue and right lateral side of the tongue (P < 0.05). In the iBMS group, VAS scores were significantly correlated to EGMt at the tip of the tongue (r = -0.59; P < 0.05) and at the right and left lateral sides of the tongue (respectively, r = -0.49 and r = -0.47; P < 0.05). These data depicted impaired taste sensitivity in iBMS patients within fungiform and foliate taste bud fields and support potent gustatory/nociceptive interaction in iBMS. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Infraorbital Foramen and Pterygopalatine Fossa Location in Dry Skulls: Anatomical Guidelines for Local Anesthesia

PubMed Central

2017-01-01

Purpose The aim of the study was to locate the infraorbital foramen (IOF) in relation to the infraorbital margin (IOM) for proper injections of local anesthetics in skull specimens. Another aim was to determine the depth of needle penetration into pterygopalatine fossa through the greater palatine canal (GPC). Materials and Methods 102 skull halves were used to measure the distances between (1) IOF and IOM and (2) IOF and alveolar ridge of maxilla at second premolar. Needles were inserted and bent at a 45° angle, passing through the GPC at the level of hard palate. The depth of the tip of needle emerging out of GPC into pterygopalatine fossa was measured. Results The mean distance between IOF and IOM was 6.46 ± 1.57 mm on the right side and 6.74 ± 1.72 mm on the left. The mean distance between IOF and alveolar bone process of the maxilla at second premolar was 29.07 ± 3.58 mm on the right side and 29.39 ± 3.78 mm on the left. The mean depth of penetration of the needle into the pterygopalatine fossa was similar on both sides. Conclusions Proper identification of IOF and pterygopalatine fossa is of great significance during local anesthesia injections, due to their close proximity to vital anatomic structures. PMID:29410916

Electrochemical polishing of notches

DOEpatents

Kephart, A.R.; Alberts, A.H.

1989-02-21

An apparatus and method are disclosed for the selective electrochemical polishing of a lateral tip of a deep longitudinal notch in a work piece used to test crack initiation properties of materials. A DC power source is connected to the work piece and to an electrode disposed laterally along the distal end of an insulated body which is inserted in the longitudinal notch. The electrode and distal end of the body are disposed along the tip of the notch, but are spaced from the notch so as to provide a lateral passage for an electrolyte. The electrolyte is circulated through the passage so that the electrolyte only contacts the work piece adjacent the passage. Conveniently, the electrolyte is circulated by use of an inlet tube and an outlet tube provided at opposite ends of the passage. These tubes are preferably detachably located adjacent the ends of the passage and suitable seals are provided. A holding device including arms to which the tubes are attached is conveniently used to rapidly and easily locate the test specimen with the passage aligned with the tubes. The electrode is preferably a wire which is located in grooves along the distal end of the insulated body and up one side of the body or a plastic sheath insulated thin metal strip. 4 figs.

Electrochemical polishing of notches

DOEpatents

Kephart, Alan R.; Alberts, Alfred H.

1989-01-01

An apparatus and method are disclosed for the selective electrochemical polishing of a lateral tip of a deep longitudinal notch in a work piece used to test crack initiation properties of materials. A DC power source is connected to the work piece and to an electrode disposed laterally along the distal end of an insulated body which is inserted in the longitudinal notch. The electrode and distal end of the body are disposed along the tip of the notch, but are spaced from the notch so as to provide a lateral passage for an electrolyte. The electrolyte is circulated through the passage so that the electrolyte only contacts the work piece adjacent the passage. Conveniently, the electrolyte is circulated by use of an inlet tube and an outlet tube provided at opposite ends of the passage. These tubes are preferably detachably located adjacent the ends of the passage and suitable seals are provided. A holding device including arms to which the tubes are attached is conveniently used to rapidly and easily locate the test specimen with the passage aligned with the tubes. The electrode is preferably a wire which is located in grooves along the distal end of the insulated body and up one side of the body or a plastic sheath insulated thin metal strip.

[New record of a bat species from China, Megaderma spasma (Linnaeus, 1758)].

PubMed

Zhang, Li-Biao; Gong, Yan-Yan; Zhu, Guang-Jian; Hong, Ti-Yu; Zhao, Xu-Dong; Mao, Xiu-Guang

2010-06-01

One male bat was collected in a cave in Cuibi Hill (N: 21 degree 53', E: 101 degree 18', H: 683 m a.s.l.), Menglun Town, Mengla County, Yunnan Province, on November 26, 2006. This bat is of medium body size, with 60.7 mm forearm and 21.4 g body mass. Its ears are large ovals and joined medially to the forehead at about 15% of the height of inner margin. The tragus of each ear is slender and distinctly bifid. The noseleaf is simple, and the posterior noseleaf is oval with obtuse tip and convex sides, a significant longitudinal ridge laying middle, which connects to intermediate noseleaf at the base. Intermediate noseleaf presents triangle with a W-shaped tip. Frontal noseleaf is horseshoe shape and attached directly to the muzzle. The tail is absent, and the second finger of each wing has only one phalanx. There are no upper incisors, Pm3 and Pm3. The upper canine has an anterior and a large posterior basal cusps. This bat is identified as lesser false vampire, Megaderma spasma, which is a new record of China. Its external and craniodental measurements were presented and compared with those of M. lyra. The specimen is preserved in Guangdong Entomological Institute.

Rolling Moments Due to Rolling and Yaw for Four Wing Models in Rotation

NASA Technical Reports Server (NTRS)

Knight, Montgomery; Wenzinger, Carl J

1932-01-01

This report presents the results of a series of autorotation and torque tests on four different rotating wing systems at various rates of roll and at several angles of yaw. The investigation covered an angle of attack range up to 90 degrees and angles of yaw of 0 degree, 5 degrees, 10 degrees, and 20 degrees. The tests were made in a 5-foot, closed-throat atmospheric wind tunnel. The object of the tests was primarily to determine the effects of various angles of yaw on the rolling moments of the rotating wings up to large angles of attack. It was found that at angles of attack above that of maximum lift the rolling moments on the wings due to yaw (or side slip) from 5 degrees to 20 degrees were roughly of the same magnitude as those due to rolling. There was a wide variation in magnitude of the rolling moment due to yaw angle. The rates and ranges of stable autorotation for the monoplane models were considerably increased by yaw, whereas for an unstaggered biplane they were little affected. The immediate cause of the rolling moment due to yaw is apparently the building up of large loads on the forward wing tip and the reduction of loads on the rearward wing tip.

Insight into the performance of multi-color InGaN/GaN nanorod light emitting diodes.

PubMed

Robin, Y; Bae, S Y; Shubina, T V; Pristovsek, M; Evropeitsev, E A; Kirilenko, D A; Davydov, V Yu; Smirnov, A N; Toropov, A A; Jmerik, V N; Kushimoto, M; Nitta, S; Ivanov, S V; Amano, H

2018-05-09

We report on the thorough investigation of light emitting diodes (LEDs) made of core-shell nanorods (NRs) with InGaN/GaN quantum wells (QWs) in the outer shell, which are grown on patterned substrates by metal-organic vapor phase epitaxy. The multi-bands emission of the LEDs covers nearly the whole visible region, including UV, blue, green, and orange ranges. The intensity of each emission is strongly dependent on the current density, however the LEDs demonstrate a rather low color saturation. Based on transmission electron microscopy data and comparing them with electroluminescence and photoluminescence spectra measured at different excitation powers and temperatures, we could identify the spatial origination of each of the emission bands. We show that their wavelengths and intensities are governed by different thicknesses of the QWs grown on different crystal facets of the NRs as well as corresponding polarization-induced electric fields. Also the InGaN incorporation strongly varies along the NRs, increasing at their tips and corners, which provides the red shift of emission. With increasing the current, the different QW regions are activated successively from the NR tips to the side-walls, resulting in different LED colors. Our findings can be used as a guideline to design effectively emitting multi-color NR-LEDs.

Flow measurement and thrust estimation of a vibrating ionic polymer metal composite

NASA Astrophysics Data System (ADS)

Chae, Woojin; Cha, Youngsu; Peterson, Sean D.; Porfiri, Maurizio

2015-09-01

Ionic polymer metal composites (IPMCs) are an emerging class of soft active materials that are finding growing application as underwater propulsors for miniature biomimetic swimmers. Understanding the hydrodynamics generated by an IPMC vibrating under water is central to the design of such biomimetic swimmers. In this paper, we propose the use of time-resolved particle image velocimetry to detail the fluid kinematics and kinetics in the vicinity of an IPMC vibrating along its fundamental structural mode. The reconstructed pressure field is ultimately used to estimate the thrust produced by the IPMC. The vibration frequency is systematically varied to elucidate the role of the Reynolds number on the flow physics and the thrust production. Experimental results indicate the formation and shedding of vortical structures from the IPMC tip during its vibration. Vorticity shedding is sustained by the pressure gradients along each side of the IPMC, which are most severe in the vicinity of the tip. The mean thrust is found to robustly increase with the Reynolds number, closely following a power law that has been derived from direct three-dimensional numerical simulations. A reduced order distributed model is proposed to describe IPMC underwater vibration and estimate thrust production, offering insight into the physics of underwater propulsion and aiding in the design of IPMC-based propulsors.

Improvement of vibration energy harvesters mechanical Q-factor through high density proof mass integration

NASA Astrophysics Data System (ADS)

Dompierre, A.; Fréchette, L. G.

2016-11-01

This paper reports on improvement of the mechanical Q-factor of resonant energy harvesters at ambient pressure via the use of tungsten proof masses by evaluating the impact of the mass size and density on the squeeze film damping. To this end, a simplified model is first proposed to evaluate cantilever beams deflection and the resulting fluid pressure build up between the mass and a near surface. The model, which accounts for simultaneous transverse and rotational motion of very long tip masses as well as for 2D fluid flow in the gap, is used to extract a scaling law for the device fluidic Q-factor Qf. This law states that Qf can be improved by either increasing the linear mass density of the tip mass or by reducing the side lengths compared to the gap height. The first approach is validated experimentally by adding a tungsten proof mass on a silicon based device and observing an improvement of the Q-factor by 103%, going from 430 to 871, while the resonance frequency drops from 457 to 127 Hz. In terms of fluidic Q-factor, this represents an increase from 562 to 1673. These results successfully demonstrate the benefits of integrating a tungsten mass to reduce the fluid losses while potentially reducing the device footprint.

A generalized one-dimensional computer code for turbomachinery cooling passage flow calculations

NASA Technical Reports Server (NTRS)

Kumar, Ganesh N.; Roelke, Richard J.; Meitner, Peter L.

1989-01-01

A generalized one-dimensional computer code for analyzing the flow and heat transfer in the turbomachinery cooling passages was developed. This code is capable of handling rotating cooling passages with turbulators, 180 degree turns, pin fins, finned passages, by-pass flows, tip cap impingement flows, and flow branching. The code is an extension of a one-dimensional code developed by P. Meitner. In the subject code, correlations for both heat transfer coefficient and pressure loss computations were developed to model each of the above mentioned type of coolant passages. The code has the capability of independently computing the friction factor and heat transfer coefficient on each side of a rectangular passage. Either the mass flow at the inlet to the channel or the exit plane pressure can be specified. For a specified inlet total temperature, inlet total pressure, and exit static pressure, the code computers the flow rates through the main branch and the subbranches, flow through tip cap for impingement cooling, in addition to computing the coolant pressure, temperature, and heat transfer coefficient distribution in each coolant flow branch. Predictions from the subject code for both nonrotating and rotating passages agree well with experimental data. The code was used to analyze the cooling passage of a research cooled radial rotor.

Deep Space 1 moves to CCAS for testing

NASA Technical Reports Server (NTRS)

1998-01-01

Workers in the Payload Hazardous Servicing Facility lower Deep Space 1 onto its transporter, for movement to the Defense Satellite Communications System Processing Facility (DPF), Cape Canaveral Air Station, where it will undergo testing. At either side of the spacecraft are its solar wings, folded for launch. When fully extended, the wings measure 38.6 feet from tip to tip. The first flight in NASA's New Millennium Program, Deep Space 1 is designed to validate 12 new technologies for scientific space missions of the next century. Onboard experiments include a solar-powered ion propulsion engine and software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propelling a spacecraft. Deep Space 1 will complete most of its mission objectives within the first two months, but may also do a flyby of a near-Earth asteroid, 1992 KD, in July 1999. Deep Space 1 will be launched aboard a Boeing Delta 7326 rocket from Launch Pad 17A, Cape Canaveral Air Station, in October. Delta II rockets are medium capacity expendable launch vehicles derived from the Delta family of rockets built and launched since 1960. Since then there have been more than 245 Delta launches.

KSC-98pc1188

NASA Image and Video Library

1998-09-30

KENNEDY SPACE CENTER, FLA. -- Workers in the Payload Hazardous Servicing Facility lower Deep Space 1 onto its transporter, for movement to the Defense Satellite Communications System Processing Facility (DPF), Cape Canaveral Air Station, where it will undergo testing. At either side of the spacecraft are its solar wings, folded for launch. When fully extended, the wings measure 38.6 feet from tip to tip. The first flight in NASA's New Millennium Program, Deep Space 1 is designed to validate 12 new technologies for scientific space missions of the next century. Onboard experiments include a solar-powered ion propulsion engine and software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propelling a spacecraft. Deep Space 1 will complete most of its mission objectives within the first two months, but may also do a flyby of a near-Earth asteroid, 1992 KD, in July 1999. Deep Space 1 will be launched aboard a Boeing Delta 7326 rocket from Launch Pad 17A, Cape Canaveral Air Station, in October. Delta II rockets are medium capacity expendable launch vehicles derived from the Delta family of rockets built and launched since 1960. Since then there have been more than 245 Delta launches

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit.

PubMed

Dixson, Ronald G; Orji, Ndubuisi G; Goldband, Ryan S

2016-01-25

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm/V is the baseline response due to the induced motion of the cantilever base.

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

PubMed Central

Dixson, Ronald G.; Orji, Ndubuisi G.; Goldband, Ryan S.

2016-01-01

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm/V is the baseline response due to the induced motion of the cantilever base. PMID:27087883

Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

NASA Astrophysics Data System (ADS)

Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

2018-04-01

We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

Local Mass and Heat Transfer on a Turbine Blade Tip

DOE PAGES

Jin, P.; Goldstein, R. J.

2003-01-01

Locmore » al mass and heat transfer measurements on a simulated high-pressure turbine blade-tip surface are conducted in a linear cascade with a nonmoving tip endwall, using a naphthalene sublimation technique. The effects of tip clearance (0.86–6.90% of chord) are investigated at various exit Reynolds numbers (4–7 × 10 5 ) and turbulence intensities (0.2 and 12.0%). The mass transfer on the tip surface is significant along its pressure edge at the smallest tip clearance. At the two largest tip clearances, the separation bubble on the tip surface can cover the whole width of the tip on the second half of the tip surface. The average mass-transfer rate is highest at a tip clearance of 1.72% of chord. The average mass-transfer rate on the tip surface is four and six times as high as on the suction and the pressure surface, respectively. A high mainstream turbulence level of 12.0% reduces average mass-transfer rates on the tip surface, while the higher mainstream Reynolds number generates higher local and average mass-transfer rates on the tip surface.« less

Evaluation of cutting efficiency of ultrasonic tips used in orthograde endodontic treatment.

PubMed

Lin, Yu-Heng; Mickel, André K; Jones, Jefferson J; Montagnese, Thomas A; González, Alvaro F

2006-04-01

The purpose of the present study was to evaluate the cutting efficiency of the three different ultrasonic tips for orthograde endodontic treatment: stainless steel, zirconium nitride-coated, and diamond-coated tips. An ultrasonic handpiece was mounted on a custom-made automated balance, and each tip repeatedly penetrated dental stone blocks to a depth of 3 mm for 10 times. The amount of time taken to penetrate 3 mm of stone was measured. The diamond-coated tips showed significantly greater cutting efficiency than either stainless steel tips or zirconium-nitride coated tips. The stainless steel tips showed initial better cutting efficiency, but over time , there is no significant difference between the cutting efficiency of the stainless steel tips and the zirconium nitride coated tips. The diamond coated tips were the only group that showed breakage in this study.

The risk of capsular breakage from phacoemulsification needle contact with the lens capsule: a laboratory study.

PubMed

Meyer, Jay J; Kuo, Annie F; Olson, Randall J

2010-06-01

To determine capsular breakage risk from contact by phacoemulsification needles by machine and tip type. Experimental laboratory investigation. Infiniti (Alcon, Inc.) with Intrepid cartridges and Signature (Abbott Medical Optics, Inc.) phacoemulsification machines were tested using 19- and 20-gauge sharp and rounded tips. Actual and unoccluded flow vacuum were determined at 550 mm Hg, bottle height of 75 cm, and machine-indicated flow rate of 60 mL/minute. Breakage from brief tip contact with a capsular surrogate and human cadaveric lenses was calculated. Nineteen-gauge tips had more flow and less unoccluded flow vacuum than 20-gauge tips for both machines, with highest unoccluded flow vacuum in the Infiniti. The 19-gauge sharp tip was more likely than the 20-gauge sharp tip to cause surrogate breakage for Signature with micropulse and Ellips (Abbott Medical Optics, Inc.) ultrasound at 100% power. For Infiniti using OZil (Alcon, Inc.) ultrasound, 20-gauge sharp tips were more likely than 19-gauge sharp tips to break the membrane. For cadaveric lenses, using rounded 20-gauge tips at 100% power, breakage rates were micropulse (2.3%), Ellips (2.3%), OZil (5.3%). Breakage rates for sharp 20-gauge Ellips tips were higher than for rounded tips. Factors influencing capsular breakage may include active vacuum at the tip, flow rate, needle gauge, and sharpness. Nineteen-gauge sharp tips were more likely than 20-gauge tips to cause breakage in lower vacuum methods. For higher-vacuum methods, breakage is more likely with 20-gauge than with 19-gauge tips. Rounded-edge tips are less likely than sharp-edged tips to cause breakage. Copyright 2010 Elsevier Inc. All rights reserved.

KSC-07pd2901

NASA Image and Video Library

2007-10-20

KENNEDY SPACE CENTER, FLA. -- Debris from apparent contact with a tree near Kennedy Space Center's Shuttle Landing Facility can be seen in the strobe light cavity on the left side of one of NASA's Shuttle Training Aircraft, or STA. The left position light and wing tip also received minor damage. The incident occurred during landing about 6:30 p.m. EDT Oct. 19 following a training session. An STA flight instructor was piloting the aircraft. The flight crew was unaware of any contact with the tree, and there were no injuries. Thunderstorms were in the area at the time of the incident, which is under investigation. The STA is a twin-engine Gulfstream II jet that was modified to simulate a space shuttle during landing. Photo credit: NASA/Kim Shiflett

KSC-07pd2900

NASA Image and Video Library

2007-10-20

KENNEDY SPACE CENTER, FLA. -- Debris from apparent contact with a tree near Kennedy Space Center's Shuttle Landing Facility can be seen in the position light cavity on the left side of one of NASA's Shuttle Training Aircraft, or STA. The left strobe light and wing tip also received minor damage. The incident occurred during landing about 6:30 p.m. EDT Oct. 19 following a training session. An STA flight instructor was piloting the aircraft. The flight crew was unaware of any contact with the tree, and there were no injuries. Thunderstorms were in the area at the time of the incident, which is under investigation. The STA is a twin-engine Gulfstream II jet that was modified to simulate a space shuttle during landing. Photo credit: NASA/Kim Shiflett

NLTE modeling of a small active region filament observed with the VTT

NASA Astrophysics Data System (ADS)

Schwartz, P.; Balthasar, H.; Kuckein, C.; Koza, J.; Gömöry, P.; Rybák, J.; Heinzel, P.; Kučera, A.

2016-11-01

An active region mini-discretionary-filament was observed with the Vacuum Tower Telescope (VTT) in Tenerife simultaneously in the He I infrared triplet using the Tenerife Infrared Polarimeter 1 (TIP 1), in Hα with the TESOS Fabry-Pérot interferometer, and in Ca II 8542 Å with the VTT spectrograph. The spectropolarimetric data were inverted using the HAZEL code and Hα profiles were modelled by solving a NLTE radiative transfer in a simple isobaric and isothermal 2D slab irradiated both from its bottom and sides from the solar surface. It was found that the mini-discretionary-filament is composed of horizontal fluxtubes, along which the cool plasma of T˜10 000 K can flow with very large, even supersonic, velocities.

Land-level changes from a late Holocene earthquake in the northern Puget lowland, Washington

USGS Publications Warehouse

Kelsey, H.M.; Sherrod, B.; Johnson, S.Y.; Dadisman, S.V.

2004-01-01

An earthquake, probably generated on the southern Whidbey Island fault zone, caused 1-2 m of ground-surface uplift on central Whidbey Island ???2800-3200 yr ago. The cause of the uplift is a fold that grew coseismically above a blind fault that was the earthquake source. Both the fault and the fold at the fault's tip are imaged on multichannel seismic refection profiles in Puget Sound immediately east of the central Whidbey Island site. Uplift is documented through contrasting histories of relative sea level at two coastal marshes on either side of the fault. Late Holocene shallow-crustal earthquakes of Mw = 6.5-7 pose substantial seismic hazard to the northern Puget Lowland. ?? 2004 Geological Society of America.

Implanon NXT: Expert tips for best-practice insertion and removal.

PubMed

Pearson, Suzanne; Stewart, Mary; Bateson, Deborah

2017-03-01

The single rod etonogestrel contraceptive implant is available in Australia as Implanon NXT. It is a highly effective, long-acting reversible contraceptive method, which is suitable for most women across the reproductive lifespan. This article provides practical advice for clinicians who already insert and remove the contraceptive implant, as well as advice for those who have not yet acquired this procedural skill. Contraceptive implant procedures are usually performed in the general practice setting. Clinicians can support women in making an informed choice to have an implant by providing information about their benefits, side effects and risks, and timely access to insertion. Training in the procedures and compliance with procedural instructions are essential to minimise risks, including deep insertion and damage to neurovascular structures.

In situ scanning tunneling microscope tip treatment device for spin polarization imaging

DOEpatents

Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

2008-04-22

A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

Comparison of actual vacuum pressures at the end of 3 phacoemulsification tips in swine eyes.

PubMed

Park, Sang Hoon; Choi, Chul Young; Kim, Joon Mo; Chang, Hae Ran; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon; Kim, Jae Chan

2009-05-01

To compare the actual vacuum pressure at the end of an aspiration bypass system (ABS) phaco tip and a conventional tip in conditions similar to those during human cataract surgery. Kangbuk Samsung Hospital, Seoul, Korea. A 4.0 mm diameter rubber eraser ball was inserted in a phacoemulsified swine eye and engaged to a phaco tip. With a vacuum pressure of 300 mm Hg, the eraser ball was pulled in the opposite direction with the phaco tip. The pulling power separating the eraser ball from the phaco tip was measured using the volume of water dripped into a container connected to the eraser ball. Measurements were taken with an Infiniti ABS tip and 2 conventional tips: Sovereign (conventional tip S) and Infiniti (conventional tip I). Measurements were taken alternatively at random in the same eye. The mean pulling power was 17.35 mL +/- 5.01 (SD) with conventional tip S and 16.85 +/- 4.45 mL with conventional tip I. The mean pulling power of the ABS tip was 13.35 +/- 4.32 mL, which was a mean 20.8% lower than that of conventional tip I (P = .016) and 23.1% lower than that of conventional tip S (P = .010). The actual vacuum pressure of the phaco tip was significantly influenced by the presence of the ABS hole. To compensate for the decrease in actual vacuum pressure, surgeons should be aware of the characteristics of the ABS tip being used and change the standard settings accordingly.

Online monitoring of dynamic tip clearance of turbine blades in high temperature environments

NASA Astrophysics Data System (ADS)

Han, Yu; Zhong, Chong; Zhu, Xiaoliang; Zhe, Jiang

2018-04-01

Minimized tip clearance reduces the gas leakage over turbine blade tips and improves the thrust and efficiency of turbomachinery. An accurate tip clearance sensor, measuring the dynamic clearances between blade tips and the turbine case, is a critical component for tip clearance control. This paper presents a robust inductive tip clearance sensor capable of monitoring dynamic tip clearances of turbine machines in high-temperature environments and at high rotational speeds. The sensor can also self-sense the temperature at a blade tip in situ such that temperature effect on tip clearance measurement can be estimated and compensated. To evaluate the sensor’s performance, the sensor was tested for measuring the tip clearances of turbine blades under various working temperatures ranging from 700 K to 1300 K and at turbine rotational speeds ranging from 3000 to 10 000 rpm. The blade tip clearance was varied from 50 to 2000 µm. The experiment results proved that the sensor can accurately measure the blade tip clearances with a temporal resolution of 10 µm. The capability of accurately measuring the tip clearances at high temperatures (~1300 K) and high turbine rotation speeds (~30 000 rpm), along with its compact size, makes it promising for online monitoring and active control of blade tip clearances of high-temperature turbomachinery.

The influence of tip shape on bending force during needle insertion

PubMed Central

van de Berg, Nick J.; de Jong, Tonke L.; van Gerwen, Dennis J.; Dankelman, Jenny; van den Dobbelsteen, John J.

2017-01-01

Steering of needles involves the planning and timely modifying of instrument-tissue force interactions to allow for controlled deflections during the insertion in tissue. In this work, the effect of tip shape on these forces was studied using 10 mm diameter needle tips. Six different tips were selected, including beveled and conical versions, with or without pre-bend or pre-curve. A six-degree-of-freedom force/torque sensor measured the loads during indentations in tissue simulants. The increased insertion (axial) and bending (radial) forces with insertion depth — the force-displacement slopes — were analyzed. Results showed that the ratio between radial and axial forces was not always proportional. This means that the tip load does not have a constant orientation, as is often assumed in mechanics-based steering models. For all tip types, the tip-load assumed a more radial orientation with increased axial load. This effect was larger for straight tips than for pre-bent or pre-curved tips. In addition, the force-displacement slopes were consistently higher for (1) increased tip angles, and for (2) beveled tips compared to conical tips. Needles with a bent or curved tip allow for an increased bending force and a decreased variability of the tip load vector orientation. PMID:28074939

Control of the Water Transport Activity of Barley HvTIP3;1 Specifically Expressed in Seeds.

PubMed

Utsugi, Shigeko; Shibasaka, Mineo; Maekawa, Masahiko; Katsuhara, Maki

2015-09-01

Tonoplast intrinsic proteins (TIPs) are involved in the transport and storage of water, and control intracellular osmotic pressure by transporting material related to the water potential of cells. In the present study, we focused on HvTIP3;1 during the periods of seed development and desiccation in barley. HvTIP3;1 was specifically expressed in seeds. An immunochemical analysis showed that HvTIP3;1 strongly accumulated in the aleurone layers and outer layers of barley seeds. The water transport activities of HvTIP3;1 and HvTIP1;2, which also accumulated in seeds, were measured in the heterologous expression system of Xenopus oocytes. When they were expressed individually, HvTIP1;2 transported water, whereas HvTIP3;1 did not. However, HvTIP3;1 exhibited water transport activity when co-expressed with HvTIP1;2 in oocytes, and this activity was higher than when HvTIP1;2 was expressed alone. This is the first report to demonstrate that the water permeability of a TIP aquaporin was activated when co-expressed with another TIP. The split-yellow fluorescent protein (YFP) system in onion cells revealed that HvTIP3;1 interacted with HvTIP1;2 to form a heterotetramer in plants. These results suggest that HvTIP3;1 functions as an active water channel to regulate water movement through tissues during the periods of seed development and desiccation. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Reduction of TIP30 in esophageal squamous cell carcinoma cells involves promoter methylation and microRNA-10b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Wenjie, E-mail: dongwenjie200581@126.com; Shen, Ruizhe; Cheng, Shidan

2014-10-31

Highlights: • TIP30 expression is frequently suppressed in ESCC. • TIP30 was hypermethylated in ESCC. • Reduction of TIP30 was significantly correlated with LN metastasis. • miR-10b is a direct regulator of TIP30. - Abstract: TIP30 is a putative tumor suppressor that can promote apoptosis and inhibit angiogenesis. However, the role of TIP30 in esophageal squamous cell carcinoma (ESCC) biology has not been investigated. Immunohistochemistry was used to investigate the expression of TIP30 in 70 ESCC. Hypermethylation of TIP30 was evaluated by the methylation specific PCR (MSP) method in ESCC (tumor and paired adjacent non-tumor tissues). Lost expression of TIP30more » was observed in 50 of 70 (71.4%) ESCC. 61.4% (43 of 70) of primary tumors analyzed displayed TIP30 hypermethylation, indicating that this aberrant characteristic is common in ESCC. Moreover, a statistically significant inverse association was found between TIP30 methylation status and expression of the TIP30 protein in tumor tissues (p = 0.001). We also found that microRNA-10b (miR-10b) targets a homologous DNA region in the 3′untranslated region of the TIP30 gene and represses its expression at the transcriptional level. Reporter assay with 3′UTR of TIP30 cloned downstream of the luciferase gene showed reduced luciferase activity in the presence of miR-10b, providing strong evidence that miR-10b is a direct regulator of TIP30. These results suggest that TIP30 expression is regulated by promoter methylation and miR-10b in ESCC.« less

A tonoplast intrinsic protein in Gardenia jasminoides

NASA Astrophysics Data System (ADS)

Gao, Lan; Li, Hao-Ming

2017-08-01

Physiological and molecular studies proved that plasma membrane intrinsic proteins (PIPs) and tonoplast intrinsic proteins (TIPs) subfamily of aquaporins play key functions in plant water homeostasis. Five specialized subgroups (TIP1-5) of TIPs have been found in higher plants, in which the TIP1 and TIP2 isoforms are the largest arbitrary groups. TIPs have high water-transport activity than PIPs, some TIPs can transport other small molecule such as urea, ammonia, hydrogen peroxide, and carbon dioxide. In this work, the structure of the putative tonoplast aquaporin from Gardenia jasminoides (GjTIP) was analyzed. Its transcript level has increased during fruit maturation. A phylogenetic analysis indicates that the protein belongs to TIP1 subfamily. A three-dimensional model structure of GjTIP was built based on crystal structure of an ammonia-permeable AtTIP2-1 from Arabidopsis thaliana. The model structure displayed as a homo-tetramer, each monomer has six trans-membrane and two half-membrane-spanning α helices. The data suggests that the GjTIP has tendency to be a mixed function aquaporin, might involve in water, urea and hydrogen peroxide transport, and the gating machanism founded in some AQPs involving pH and phosphorylation response have not been proved in GjTIP.

Gravitropism and phototropism of oat coleoptiles: Post-tropic autostraightening and tissue shrinkage during tropism

NASA Astrophysics Data System (ADS)

Tarui, Y.; Iino, M.

1999-01-01

We measured changes in length on the two opposite sides of the red-light-grown oat (Avena sativa L.) coleoptiles subjected to either gravitropic or phototropic stimulation and subsequently rotated on a horizontal clinostat. The length measurement was conducted using three 5 mm-long zones delimited by ink markers from the tip. Curvature of each zone was analyzed from the length difference between the two sides. Gravitropism was induced by displacing the seedling from the vertical by 30° or 90° for 25 min. Phototropism was induced by exposing the coleoptile to unilateral blue light for 30 s, which provided a fluence (1.0 μmol m-2) optimal for the pulse-induced positive phototropism or a lower, suboptimal fluence (0.03 μmol m-2). After negatively gravitropic bending, the upper two zones straightened rapidly at either displacement angle. After positively phototropic bending, straightening occurred, but only in the top zone and at the lower fluence. The upper two zones straightened rapidly, however, when bilateral blue light (30 s; 15 μmol m-2 from either direction) was applied 25 min after unilateral stimulation at the higher fluence. Bilateral blue light alone induced no curvature. These results confirm that the straightening of gravitropically bent coleoptiles is autonomic, and suggest that a similar autonomic response participates in the straightening of phototropically bent coleoptiles. Suppression of elongation on the concave side of the coleoptile mainly accounted for gravitropic and phototropic curvatures. The concave side of the top zone shrank during both tropisms. This shrinkage progressed at a high rate from the beginning of curvature response, suggesting that a drop in turgor pressure is the main and direct cause of the shrinkage.

High-resolution Near-infrared Observations of a Small Cluster Associated with a Bright-rimmed Cloud in W5

NASA Astrophysics Data System (ADS)

Imai, Rieko; Sugitani, Koji; Miao, Jingqi; Fukuda, Naoya; Watanabe, Makoto; Kusune, Takayoshi; Pickles, Andrew J.

2017-08-01

We carried out near-infrared (IR) observations to examine star formation toward the bright-rimmed cloud SFO 12, of which the main exciting star is O7V star in W5-W. We found a small young stellar object (YSO) cluster of six members embedded in the head of SFO 12 facing its exciting star, aligned along the UV radiation incident direction from the exciting star. We carried out high-resolution near-IR observations with the Subaru adaptive optics (AO) system and revealed that three of the cluster members appear to have circumstellar envelopes, one of which shows an arm-like structure in its envelope. Our near-IR and {L}\\prime -band photometry and Spitzer IRAC data suggest that formation of two members at the tip side occurred in advance of other members toward the central part, under our adopted assumptions. Our near-IR data and previous studies imply that more YSOs are distributed in the region just outside the cloud head on the side of the main exciting star, but there is little sign of star formation toward the opposite side. We infer that star formation has been sequentially occurring from the exciting star side to the central part. We examined archival data of far-infrared and CO (J=3-2) which reveals that, unlike in the optical image, SFO 12 has a head-tail structure that is along the UV incident direction. This suggests that SFO 12 is affected by strong UV from the main exciting star. We discuss the formation of this head-tail structure and star formation there by comparing with a radiation-driven implosion (RDI) model.

Effect of fluoride on root resorption following heavy and light orthodontic force application for 4 weeks and 12 weeks of retention.

PubMed

Karadeniz, Ersan I; Gonzales, Carmen; Turk, Tamer; Isci, Devrim; Sahin-Saglam, Aynur M; Alkis, Huseyin; Elekdag-Turk, Selma; Darendeliler, M Ali

2013-05-01

To evaluate the null hypothesis that fluoride intake via drinking water has no effect on orthodontic root resorption in humans after orthodontic force application for 4 weeks and 12 weeks of retention. Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from two cities in Turkey. These cities had a high and low fluoride concentration in public water of ≥2 pm and ≤0.05 pm, respectively. The patients were randomly separated into four groups of 12 each: group 1HH, high fluoride (≥2 ppm) and heavy force (225 g); group 2LH, low fluoride (≤0.05 ppm) and heavy force; group 3HL, high fluoride and light force (25 g); and group 4LL, low fluoride and light force. Light or heavy buccal tipping force was applied on the upper first premolars for 28 days. At day 28, the left premolars were extracted (positive control side); the right premolars (experimental side) were extracted after 12 weeks of retention. The samples were analyzed with microcomputed tomography. On the positive control side, under heavy force application, the high fluoride groups exhibited less root resorption (P  =  .015). On the experimental side, it was found that fluoride reduced the total volume of root resorption craters; however, this effect was not statistically significant (P  =  .237). Moreover, the results revealed that under heavy force application experimental teeth exhibited more root resorption than positive control groups. The null hypothesis could not be rejected. High fluoride intake from public water did not have a beneficial effect on the severity of root resorption after a 4-week orthodontic force application and 12 weeks of passive retention.

Gravitropism and phototropism of oat coleoptiles: post-tropic autostraightening and tissue shrinkage during tropism.

PubMed

Tarui, Y; Iino, M

1999-01-01

We measured changes in length on the two opposite sides of the red-light-grown oat (Avena sativa L.) coleoptiles subjected to either gravitropic or phototropic stimulation and subsequently rotated on a horizontal clinostat. The length measurement was conducted using three 5 mm-long zones delimited by ink markers from the tip. Curvature of each zone was analyzed from the length difference between the two sides. Gravitropism was induced by displacing the seedling from the vertical by 30 degrees or 90 degrees for 25 min. Phototropism was induced by exposing the coleoptile to unilateral blue light for 30 s, which provided a fluence (1.0 micromoles m-2) optimal for the pulse-induced positive phototropism or a lower, suboptimal fluence (0.03 micromoles m-2). After negatively gravitropic bending, the upper two zones straightened rapidly at either displacement angle. After positively phototropic bending, straightening occurred, but only in the top zone and at the lower fluence. The upper two zones straightened rapidly, however, when bilateral blue light (30 s; 15 micromoles m-2 from either direction) was applied 25 min after unilateral stimulation at the higher fluence. Bilateral blue light alone induced no curvature. These results confirm that the straightening of gravitropically bent coleoptiles is autonomic, and suggest that a similar autonomic response participates in the straightening of phototropically bent coleoptiles. Suppression of elongation on the concave side of the coleoptile mainly accounted for gravitropic and phototropic curvatures. The concave side of the top zone shrank during both tropisms. This shrinkage progressed at a high rate from the beginning of curvature response, suggesting that a drop in turgor pressure is the main and direct cause of the shrinkage.

Evaluation of the safety and efficiency of novel metallic implant scaler tips manufactured by the powder injection molding technique.

PubMed

Chun, Kyung A; Kum, Kee-Yeon; Lee, Woo-Cheol; Baek, Seung-Ho; Choi, Hae-Won; Shon, Won-Jun

2017-07-11

Although many studies have compared the properties of ultrasonic scaling instruments, it remains controversial as to which is most suitable for implant scaling. This study evaluated the safety and efficiency of novel metallic ultrasonic scaler tips made by the powder injection molding (PIM) technique on titanium surfaces. Mechanical instrumentation was carried out using four types of metal scaler tips consisting of copper (CU), bronze (BR), 316 L stainless steel (316 L), and conventional stainless steel (SS) tips. The instrumented surface alteration image of samples was viewed with scanning electron microscope (SEM) and surface profile of the each sample was investigated with confocal laser scanning microscopy (CLSM). Arithmetic mean roughness (Ra) and maximum height roughness (Rmax) of titanium samples were measured and dissipated power of the scaler tip was estimated for scaling efficiency. The average Ra values caused by the 316 L and SS tip were about two times higher than those of the CU and BR tips (p < 0.05). The Rmax value showed similar results. The efficiency of the SS tip was about 3 times higher than that of CU tip, the 316 L tip is about 2.7 times higher than that of CU tip, and the BR tip is about 1.2 times higher than that of CU tip. Novel metallic bronze alloy ultrasonic scaler tip minimally damages titanium surfaces, similar to copper alloy tip. Therefore, this bronze alloy scaler tip may be promising instrument for implant maintenance therapy.

Normal and variant anatomy of the nasal tip.

PubMed

Ketcham, Amy S; Dobratz, Eric J

2012-04-01

A thorough understanding of nasal tip anatomy is a prerequisite to understanding the nuances of restructuring the nasal tip. The three-dimensional structural anatomy of the nasal tip is complex. Additionally, the interrelationship between these structures determines the ultimate form and function of the nasal tip. As a result, alteration of one structure in the tip will often lead to change in other portions of the nasal tip. This dynamic concept of anatomy in the nasal tip makes proper alteration of the nasal tip one of the most challenging tasks faced by a rhinoplasty surgeon. This article provides a fundamental knowledge of the normal anatomy of the tip structures and how their interaction with each other determines the shape and support of the lower portion of the nose. It also provides a description of some common variants of tip anatomy that cause patients to seek consultation for rhinoplasty. A proper understanding of the concepts presented provides a foundation to build on as the reader continues to explore the "nuances of the nasal tip." Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Reference system for scanning probe tip fingerprinting

NASA Astrophysics Data System (ADS)

Turansky, Robert; Bamidele, Joseph; Sugawara, Yasuhiro; Kantorovitch, Lev; Stich, Ivan

2012-02-01

Knowledge of the chemical structure of the tip asperity in Non-Contact Atomic Force Microscopy (NC-AFM) is crucial as controlled manipulation of atoms and/or molecules on surfaces can only be performed if this information is available. However, a simple and robust protocol for ensuring a specific tip termination has not yet been developed. We propose a procedure for chemical tip finger printing and an example of a reference system, the oxygen-terminated Cu(110) surface, that enables one to ensure a specific tip termination with Si, Cu, or O atoms. To follow this up and unambiguously determine tip types, we performed a theoretical DFT study of the line scans with the tip models in question and found that the tip characterization made based on experimental results (Cu/O-terminated tip imaging Cu/O atoms) is in fact incorrect and the opposite is true (Cu/O-terminated tip imaging O/Cu atoms). This protocol allows the tip asperity's chemical structure to be verified and established both before as well as at any stage of the manipulation experiment when numerous tip changes may take place.

Shell-Isolated Tip-Enhanced Raman and Fluorescence Spectroscopy.

PubMed

Huang, Ya-Ping; Huang, Sheng-Chao; Wang, Xiang-Jie; Bodappa, Nataraju; Li, Chao-Yu; Yin, Hao; Su, Hai-Sheng; Meng, Meng; Zhang, Hua; Ren, Bin; Yang, Zhi-Lin; Zenobi, Renato; Tian, Zhong-Qun; Li, Jian-Feng

2018-06-18

Tip-enhanced Raman spectroscopy can provide molecular fingerprint information with ultrahigh spatial resolution, but the tip will be easily contaminated, thus leading to artifacts. It also remains a great challenge to establish tip-enhanced fluorescence because of the quenching resulting from the proximity of the metal tip. Herein, we report shell-isolated tip-enhanced Raman and fluorescence spectroscopies by employing ultrathin shell-isolated tips fabricated by atomic layer deposition. Such shell-isolated tips not only show outstanding electromagnetic field enhancement in TERS but also exclude interference by contaminants, thus greatly promoting applications in solution. Tip-enhanced fluorescence has also been achieved using these shell-isolated tips, with enhancement factors of up to 1.7×10 3 , consistent with theoretical simulations. Furthermore, tip-enhanced Raman and fluorescence signals are acquired simultaneously, and their relative intensities can be manipulated by changing the shell thickness. This work opens a new avenue for ultrahigh resolution surface analysis using plasmon-enhanced spectroscopies. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High versus moderate energy use of bipolar fractional radiofrequency in the treatment of acne scars: a split-face double-blinded randomized control trial pilot study.

PubMed

Phothong, Weeranut; Wanitphakdeedecha, Rungsima; Sathaworawong, Angkana; Manuskiatti, Woraphong

2016-02-01

Bipolar fractional radiofrequency (FRF) device was firstly FDA-approved for treating atrophic acne scar in 2008 through the process of dermal coagulation and minimal epidermal ablation. The average energy at 60 mJ/pin was widely used to treat atrophic acne scars. However, the higher energy was delivered, the deeper ablation and coagulation were found. At present, the new generation of a device with bipolar FRF technology with electrode-pin tip was developed to maximize ability to deliver energy up to 100 mJ/pin. The objective of the study was to explore and compare the efficacy of utilizing high energy (100 mJ/pin) and moderate energy (60 mJ/pin) of bipolar fractional radiofrequency in treatment of atrophic acne scar in Asians. This is a split-face, double-blinded, randomized control trial, pilot study by using parallel group design technique. Thirty healthy subjects with Fitzpatrick skin phototype III-IV diagnosed as atrophic acne scares were enrolled. All subjects received four monthly sessions of bipolar FRF treatment. Left and right facial sides of individual patients were randomly assigned for different energy (high energy at 100 mJ/pin versus moderate energy at 60 mJ/pin). Acne scars improvement was blinded graded by dermatologist using global acne scarring score (GASS) which was subjectively evaluated at baseline, 1-, 3-, and 6-month follow-up. Objective scar analysis was also done using UVA-light video camera to measure scar volume, skin smoothness, and wrinkle at baseline, 3-, and 6-month follow-up after the last treatment. Side effects including pain, erythema, swelling, and crusting were also recorded. Thirty subjects completed the study with full 4-treatment course. The mean GASS of high energy side and moderate energy side was significantly reduced at 1-, 3-, and 6-month follow-up visits. At 1 month follow-visit, high energy side demonstrated significant improvement compared with moderate energy side (p = 0.03). Postinflammatory hyperpigmentation (PIH) developed in 21/120 sessions in high energy side (17.5 %) and 16/120 sessions in moderate energy side (13.3 %). Pain score and the duration of erythema after treatments were significant higher on the side that was treated with high energy. Bipolar FRF device was safe and effective in the treatment of atrophic acne scars in Asians. High energy setting demonstrated significant higher efficacy at 1 month follow-visit. However, the efficacy of both energy settings was comparable at 3- and 6-month follow-up. In addition, side effects were significantly more intense on the side treated with high energy.

Gravity-dependent regulation of red light induced moss protonemata branching and gametophore bud formation

NASA Astrophysics Data System (ADS)

Ripetskyj, R. T.; Kit, N. A.

Isolated leafy shoots of the moss Pottia intermedia positioned horizontally on the agar surface in vertically oriented petri dishes regenerate unbranching negatively gravitropic protonemata on upper side of the regenerant. Gravity determines the site of regeneration not the process itself. White light of low intensity unsufficient to induce positive phototropism of dark-grown protonemata can, however, provoke their branching and gametophore bud formation (Ripetskyj et al., 1998; 1999). The presented experiments have been carried out with red light in Biological Research in Canisters/Light Emitting Diode (BRIC/LED) hardware developed at Kennedy Space Center, USA. Seven-day-old dark-grown negatively gravitropic secondary P. intermedia protonemata were positioned differently with respect to gravity vector and to the source of red light of low, 1 or 2 μ mol\\cdot m-2\\cdot s-1, intensities. The light induced intensive branching of the protonemata and gametophore bud formation initiation site of both processes as well as the direction of growth of branches and buds being depent on the position of protonemata with respect to gravity and light vectors. Vertically positioned, i.e. ungravistimulated, dark grown protonemata illuminated from one side with red light of 2 μ mol\\cdot m-2\\cdot s-1 intensity produced 96,9 ± 2,2% of side branches and buds growing directly towards the light source from the lit protonema side. Horizontally disposed protonemata irradiated from below with red light of the same intensity regenerate 31,7 ± 3,9% of branches and buds on the upper, i.e. shaded protonemata side, the upward growth of which should undoubtedly be determined by gravity. In vertically disposed protonemata illuminated with red light of 1 μ mol\\cdot m-2\\cdot s-1 intensity from aside 31,9 ± 5,5% of side branches and buds arised on shaded protonema side and grew away from the light. Illumination of the protonemata in horizontal position from below increased the number of upgrowing branches and buds on upper shaded protonemata side to 76,9 ± 2,4%. The results convincingly speak for stimulating effect of the interaction of gravity and red light of low intensity. Characteristically, the number of side branches and buds on upper side of horizontally disposed protonemata illuminated from below (76,9 ± 2,4%) or parallely to protonemata length from their tips (86,0 ± 5,3%) were slightly, however, statistically significantly, greater than in the case of illumination from above (62,9 ± 3,1%). The effect may be probably be explained by some intensification of gravity action with red light of low intensity from shading of upper cell side or from lighting parallelly with respect to the cell surface. This research was supported by NASA grant NN-09(R).

Skin Cancer Trends

MedlinePlus

... Children from the Sun? Are There Benefits to Spending Time Outdoors? The Surgeon General’s Call to Action to Prevent Skin Cancer Related Resources Sun Safety Tips for Men Tips for Families Tips for Schools Tips for Employers Tips for ...

The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping.

PubMed

Clifton, Sara M; Herbers, Eileen; Chen, Jack; Abrams, Daniel M

2018-02-01

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping

NASA Astrophysics Data System (ADS)

Clifton, Sara M.; Herbers, Eileen; Chen, Jack; Abrams, Daniel M.

2018-02-01

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

Conflicting Selection Pressures Will Constrain Viral Escape from Interfering Particles: Principles for Designing Resistance-Proof Antivirals.

PubMed

Rast, Luke I; Rouzine, Igor M; Rozhnova, Ganna; Bishop, Lisa; Weinberger, Ariel D; Weinberger, Leor S

2016-05-01

The rapid evolution of RNA-encoded viruses such as HIV presents a major barrier to infectious disease control using conventional pharmaceuticals and vaccines. Previously, it was proposed that defective interfering particles could be developed to indefinitely control the HIV/AIDS pandemic; in individual patients, these engineered molecular parasites were further predicted to be refractory to HIV's mutational escape (i.e., be 'resistance-proof'). However, an outstanding question has been whether these engineered interfering particles-termed Therapeutic Interfering Particles (TIPs)-would remain resistance-proof at the population-scale, where TIP-resistant HIV mutants may transmit more efficiently by reaching higher viral loads in the TIP-treated subpopulation. Here, we develop a multi-scale model to test whether TIPs will maintain indefinite control of HIV at the population-scale, as HIV ('unilaterally') evolves toward TIP resistance by limiting the production of viral proteins available for TIPs to parasitize. Model results capture the existence of two intrinsic evolutionary tradeoffs that collectively prevent the spread of TIP-resistant HIV mutants in a population. First, despite their increased transmission rates in TIP-treated sub-populations, unilateral TIP-resistant mutants are shown to have reduced transmission rates in TIP-untreated sub-populations. Second, these TIP-resistant mutants are shown to have reduced growth rates (i.e., replicative fitness) in both TIP-treated and TIP-untreated individuals. As a result of these tradeoffs, the model finds that TIP-susceptible HIV strains continually outcompete TIP-resistant HIV mutants at both patient and population scales when TIPs are engineered to express >3-fold more genomic RNA than HIV expresses. Thus, the results provide design constraints for engineering population-scale therapies that may be refractory to the acquisition of antiviral resistance.

Regulation of Histone Acetyltransferase TIP60 Function by Histone Deacetylase 3

PubMed Central

Yi, Jingjie; Huang, Xiangyang; Yang, Yuxia; Zhu, Wei-Guo; Gu, Wei; Luo, Jianyuan

2014-01-01

The key member of the MOZ (monocyticleukaemia zinc finger protein), Ybf2/Sas3, Sas2, and TIP60 acetyltransferases family, Tat-interactive protein, 60 kD (TIP60), tightly modulates a wide array of cellular processes, including chromatin remodeling, gene transcription, apoptosis, DNA repair, and cell cycle arrest. The function of TIP60 can be regulated by SIRT1 through deacetylation. Here we found that TIP60 can also be functionally regulated by HDAC3. We identified six lysine residues as its autoacetylation sites. Mutagenesis of these lysines to arginines completely abolishes the autoacetylation of TIP60. Overexpression of HDAC3 increases TIP60 ubiquitination levels. However, unlike SIRT1, HDAC3 increased the half-life of TIP60. Further study found that HDAC3 colocalized with TIP60 both in the nucleus and the cytoplasm, which could be the reason why HDAC3 can stabilize TIP60. The deacetylation of TIP60 by both SIRT1 and HDAC3 reduces apoptosis induced by DNA damage. Knockdown of HDAC3 in cells increased TIP60 acetylation levels and increased apoptosis after DNA damage. Together, our findings provide a better understanding of TIP60 regulation mechanisms, which is a significant basis for further studies of its cellular functions. PMID:25301942

Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

NASA Astrophysics Data System (ADS)

Duan, Fajie; Zhang, Jilong; Jiang, Jiajia; Guo, Haotian; Ye, Dechao

2016-01-01

Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

Numerical simulation of tip vortices of wings in subsonic and transonic flows

NASA Technical Reports Server (NTRS)

Srinivasan, G. R.; Mccroskey, W. J.; Baeder, J. D.; Edwards, T. A.

1986-01-01

A multi block zonal algorithm which solves the thin-layer Navier-Stokes and the Euler equations is used to numerically simulate the formation and roll-up of the tip vortex in both subsonic and transonic flows. Four test cases which used small and large aspect ratio wings have been considered to examine the influence of the tip-cap shape, the tip planform and the free-stream Mach number. It appears that both the tip-planform and the tip-cap shape have some influence on the formation of the tip vortex, but its subsequent roll-up seems to be more influenced by the tip-planform shape. In general, a good definition of the formation and the roll-up of the tip vortex has been observed for all the cases considered here. Comparions of the numerical results with the limited, available experimental data show good agreement with both the surface pressures and the tip-vortex strength.

DNA-binding activity of TNF-{alpha} inducing protein from Helicobacter pylori

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuzuhara, T.; Suganuma, M.; Oka, K.

2007-11-03

Tumor necrosis factor-{alpha} (TNF-{alpha}) inducing protein (Tip{alpha}) is a carcinogenic factor secreted from Helicobacter pylori (H. pylori), mediated through both enhanced expression of TNF-{alpha} and chemokine genes and activation of nuclear factor-{kappa}B. Since Tip{alpha} enters gastric cancer cells, the Tip{alpha} binding molecules in the cells should be investigated. The direct DNA-binding activity of Tip{alpha} was observed by pull down assay using single- and double-stranded genomic DNA cellulose. The surface plasmon resonance assay, indicating an association between Tip{alpha} and DNA, revealed that the affinity of Tip{alpha} for (dGdC)10 is 2400 times stronger than that of del-Tip{alpha}, an inactive Tip{alpha}. This suggestsmore » a strong correlation between DNA-binding activity and carcinogenic activity of Tip{alpha}. And the DNA-binding activity of Tip{alpha} was first demonstrated with a molecule secreted from H. pylori.« less

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips.

PubMed

Tewari, Sumit; Bastiaans, Koen M; Allan, Milan P; van Ruitenbeek, Jan M

2017-01-01

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

Energy output reduction and surface alteration of quartz and sapphire tips following Er:YAG laser contact irradiation for tooth enamel ablation.

PubMed

Eguro, Toru; Aoki, Akira; Maeda, Toru; Takasaki, Aristeo Atsushi; Hasegawa, Mitsuru; Ogawa, Masaaki; Suzuki, Takanori; Yonemoto, Kazuaki; Ishikawa, Isao; Izumi, Yuichi; Katsuumi, Ichiroh

2009-10-01

Despite the recent increase in application of Er:YAG laser for various dental treatments, limited information is available regarding the contact tips. This study examined the changes in energy output and surface condition of quartz and sapphire contact tips after Er:YAG laser contact irradiation for tooth enamel ablation. Ten sets of unused quartz or sapphire contact tips were employed for contact irradiation to sound enamel of extracted teeth. The teeth were irradiated with Er:YAG laser at approximately 75 J/cm(2)/pulse and 20 Hz under water spray for 60 minutes. The energy output was measured before and every 5 minutes after irradiation, and the changes in morphology and chemical composition of the contact surface were analyzed. The energy output significantly decreased with time in both tips. The energy output from the sapphire tips was generally higher on average than that of the quartz. The contact surfaces of all the used quartz tips were concave and irregular. Most of the sapphire tips also appeared rough with crater formation and fractures, except for a few tips in which a high energy output and the original smooth surface were maintained. Spots of melted tooth substances were seen attached to the surface of both tips. In contact enamel ablation, the sapphire tip appeared to be more resistant than the quartz tip. The quartz tips showed similar patterns of energy reduction and surface alteration, whereas the sapphire tips revealed a wider and more characteristic variation among tips. Lasers Surg. Med. 41:595-604, 2009. (c) 2009 Wiley-Liss, Inc.

Effect of tip flange on tip leakage flow of small axial flow fans

NASA Astrophysics Data System (ADS)

Zhang, Li; Jin, Yingzi; Jin, Yuzhen

2014-02-01

Aerodynamic performance of an axial flow fan is closely related to its tip clearance leakage flow. In this paper, the hot-wire anemometer is used to measure the three dimensional mean velocity near the blade tips. Moreover, the filtered N-S equations with finite volume method and RNG k-ɛ turbulence model are adopted to carry out the steady simulation calculation of several fans that differ only in tip flange shape and number. The large eddy simulation and the FW-H noise models are adopted to carry out the unsteady numerical calculation and aerodynamic noise prediction. The results of simulation calculation agree roughly with that of tests, which proves the numerical calculation method is feasible.The effects of tip flange shapes and numbers on the blade tip vortex structure and the characteristics are analyzed. The results show that tip flange of the fan has a certain influence on the characteristics of the fan. The maximum efficiencies for the fans with tip flanges are shifted towards partial flow with respect to the design point of the datum fan. Furthermore, the noise characteristics for the fans with tip flanges have become more deteriorated than that for the datum fan. Tip flange contributes to forming tip vortex shedding and the effect of the half-cylinder tip flange on tip vortex shedding is obvious. There is a distinct relationship between the characteristics of the fan and tip vortex shedding. The research results provide the profitable reference for the internal flow mechanism of the performance optimization of small axial flow fans.

Nanostar probes for tip-enhanced spectroscopy

NASA Astrophysics Data System (ADS)

Kim, Woong; Kim, Nara; Park, Joon Won; Kim, Zee Hwan

2015-12-01

To overcome the current limit of tip-enhanced spectroscopy that is based on metallic nano-probes, we developed a new scanning probe with a metallic nanostar, a nanoparticle with sharp spikes. A Au nanoparticle of 5 nm was first attached to the end of a tip through DNA-DNA hybridization and mechanical pick-up. The nanoparticle was converted to a nanostar with a core diameter of ~70 nm and spike lengths between 50 nm and 80 nm through the reduction of Au3+ with ascorbic acid in the presence of Ag+. Fabrication yields of such tips exceeded 60%, and more than 80% of such tips showed a mechanical durability sufficient for use in scanning microscopy. Effectiveness of the new probes for tip-enhanced Raman scattering (TERS) and tip-enhanced fluorescence (TEF) was confirmed. The probes exhibited the necessary enhancement for TEF, and the tip-on and tip-off ratios varied between 5 and 100. This large tip-to-tip variability may arise from the uncontrolled orientation of the apexes of the spike with respect to the sample surface, which calls for further fabrication improvement. The result overall supports a new fabrication approach for the probe that is effective for tip-enhanced spectroscopy.To overcome the current limit of tip-enhanced spectroscopy that is based on metallic nano-probes, we developed a new scanning probe with a metallic nanostar, a nanoparticle with sharp spikes. A Au nanoparticle of 5 nm was first attached to the end of a tip through DNA-DNA hybridization and mechanical pick-up. The nanoparticle was converted to a nanostar with a core diameter of ~70 nm and spike lengths between 50 nm and 80 nm through the reduction of Au3+ with ascorbic acid in the presence of Ag+. Fabrication yields of such tips exceeded 60%, and more than 80% of such tips showed a mechanical durability sufficient for use in scanning microscopy. Effectiveness of the new probes for tip-enhanced Raman scattering (TERS) and tip-enhanced fluorescence (TEF) was confirmed. The probes exhibited the necessary enhancement for TEF, and the tip-on and tip-off ratios varied between 5 and 100. This large tip-to-tip variability may arise from the uncontrolled orientation of the apexes of the spike with respect to the sample surface, which calls for further fabrication improvement. The result overall supports a new fabrication approach for the probe that is effective for tip-enhanced spectroscopy. Electronic supplementary information (ESI) available: Illustrations of TERS and TEF experiments, information about the TEM images, scheme of surface preparation and peak assignments of TERS spectra. See DOI: 10.1039/c5nr06657c

Probe tip heating assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitz, Roger William; Oh, Yunje

A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably receivedmore » and clamped within the socket.« less

The tonoplast intrinsic aquaporin (TIP) subfamily of Eucalyptus grandis: Characterization of EgTIP2, a root-specific and osmotic stress-responsive gene.

PubMed

Rodrigues, Marcela I; Bravo, Juliana P; Sassaki, Flávio T; Severino, Fábio E; Maia, Ivan G

2013-12-01

Aquaporins have important roles in various physiological processes in plants, including growth, development and adaptation to stress. In this study, a gene encoding a root-specific tonoplast intrinsic aquaporin (TIP) from Eucalyptus grandis (named EgTIP2) was investigated. The root-specific expression of EgTIP2 was validated over a panel of five eucalyptus organ/tissues. In eucalyptus roots, EgTIP2 expression was significantly induced by osmotic stress imposed by PEG treatment. Histochemical analysis of transgenic tobacco lines (Nicotiana tabacum SR1) harboring an EgTIP2 promoter:GUS reporter cassette revealed major GUS staining in the vasculature and in root tips. Consistent with its osmotic-stress inducible expression in eucalyptus, EgTIP2 promoter activity was up-regulated by mannitol treatment, but was down-regulated by abscisic acid. Taken together, these results suggest that EgTIP2 might be involved in eucalyptus response to drought. Additional searches in the eucalyptus genome revealed the presence of four additional putative TIP coding genes, which could be individually assigned to the classical TIP1-5 groups. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Microlensed dual-fiber probe for depth-resolved fluorescence measurements

NASA Astrophysics Data System (ADS)

Choi, Hae Young; Ryu, Seon Young; Kim, Jae Young; Kim, Geon Hee; Park, Seong Jun; Lee, Byeong Ha; Chang, Ki Soo

2011-07-01

We propose and demonstrate a compact microlensed dual-fiber probe that has a good collection efficiency and a high depth-resolution ability for fluorescence measurements. The probe is formed with a conventional fusion splicer creating a common focusing lens on two fibers placed side by side. The collection efficiency of the fabricated probe was evaluated by measuring the fluorescence signal of a fresh ginkgo leaf. It was shown experimentally that the proposed probe could effectively collect the fluorescence signal with a six-fold increase compared to that of a general flat-tipped probe. The beam propagation method was used to design a probe with an optimized working distance and an improved resolving depth. It was found that the working distance depends mainly on the radius of curvature of the lens, whereas the resolving depth is determined by the core diameters of the illumination and collection fibers. The depth-resolved ability of probes with working distances of ~100 μm and 300 μm was validated by using a two-layer tissue phantom. The experimental results demonstrate that the microlensed dual-fiber probe has the potential to facilitate depth-resolved fluorescence detection of epithelial tissue.

High-Speed Additive Manufacturing Through High-Aspect-Ratio Nozzles

NASA Astrophysics Data System (ADS)

Shaw, Leon; Islam, Mashfiqul; Li, Jie; Li, Ling; Ayub, S. M. Imran

2018-03-01

The feasibility of layer-by-layer manufacturing through high-aspect-ratio (HAR) nozzles for microextrusion of paste to deposit planes has been investigated. Various conditions for paste extrusion, including nozzle moving speed, piston speed, extrusion rate, and distance between the nozzle tip and substrate, have been evaluated. By linking various microextrusion parameters together with the aid of a critical distance concept derived from microextrusion using circular nozzles and addressing the extrusion delay in response to the change of the piston speed and air pocket problems properly, we successfully microextruded single planes, multilayer objects, and larger planes made of multiple smaller planes side by side through HAR nozzles. It is further demonstrated that the X- Y dimensions of an extruded plane in the steady-state extrusion stage are determined by the nozzle travel distance and the length of the HAR nozzle opening if microextrusion is conducted with proper conditions. However, the height of the extruded plane is not only determined by the microextrusion conditions, but also affected by the drying shrinkage of the paste after microextrusion. This demonstration of the feasibility of using a HAR nozzle machine opens the door to manufacture of multimaterial, multilayer devices with high productivity in the near future.

Pressure-assisted melt-filling and optical characterization of Au nano-wires in microstructured fibers.

PubMed

Lee, H W; Schmidt, M A; Russell, R F; Joly, N Y; Tyagi, H K; Uebel, P; Russell, P St J

2011-06-20

We report a novel splicing-based pressure-assisted melt-filling technique for creating metallic nanowires in hollow channels in microstructured silica fibers. Wires with diameters as small as 120 nm (typical aspect ration 50:1) could be realized at a filling pressure of 300 bar. As an example we investigate a conventional single-mode step-index fiber with a parallel gold nanowire (wire diameter 510 nm) running next to the core. Optical transmission spectra show dips at wavelengths where guided surface plasmon modes on the nanowire phase match to the glass core mode. By monitoring the side-scattered light at narrow breaks in the nanowire, the loss could be estimated. Values as low as 0.7 dB/mm were measured at resonance, corresponding to those of an ultra-long-range eigenmode of the glass-core/nanowire system. By thermal treatment the hollow channel could be collapsed controllably, permitting creation of a conical gold nanowire, the optical properties of which could be monitored by side-scattering. The reproducibility of the technique and the high optical quality of the wires suggest applications in fields such as nonlinear plasmonics, near-field scanning optical microscope tips, cylindrical polarizers, optical sensing and telecommunications.

Low reflection and field localization over surface plasmon device with subwavelength patterned aluminum film

NASA Astrophysics Data System (ADS)

Yuan, Ying; Peng, Sha; Long, Huabao; Liu, Runhan; Wei, Dong; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

2018-02-01

In this paper, we propose a new device composed of patterned sub-wavelength arrays to investigate surface plasmons (SPs) over sub-wavelength metal nano-structures. The device consists of silicon substrate and sub-wavelength patterns fabricated on a layer of aluminum film with nanometer thickness. Each sub-wavelength pattern formed in aluminum film is composed of a basic nano-square and twelve triangles for shaping single nano-pattern, which are uniformly distributed on the four sides of each square. Reflectance spectra and electric field distribution in infrared region are simulated. Numerical simulation results demonstrate that the device can efficiently lower its reflectance in infrared spectrum, and the response frequency can be controlled by only changing the device parameters such as square side length and then triangle vertex angle. Besides, the simulated electric field distribution of the device shows obviously field localization effect at the edges of aluminum film nano-structure. The electric filed around the tips of aluminum triangles is localized into sub-wavelength scale, so as to be beyond the common diffraction limitation. Our work will help to reveal the interesting properties of SPs device, and also bring new prospect of photonic device.

Experimental measurements and analytical analysis related to gas turbine heat transfer. Part 1: Time-averaged heat-flux and surface-pressure measurements on the vanes and blades of the SSME fuel-side turbine and comparison with prediction. Part 2: Phase-resolved surface-pressure and heat-flux measurements on the first blade of the SSME fuel-side turbine

NASA Technical Reports Server (NTRS)

1994-01-01

Time averaged Stanton number and surface-pressure distributions are reported for the first-stage vane row, the first stage blade row, and the second stage vane row of the Rocketdyne Space Shuttle Main Engine two-stage fuel-side turbine. Unsteady pressure envelope measurements for the first blade are also reported. These measurements were made at 10 percent, 50 percent, and 90 percent span on both the pressure and suction surfaces of the first stage components. Additional Stanton number measurements were made on the first stage blade platform blade tip, and shroud, and at 50 percent span on the second vane. A shock tube was used as a short duration source of heated and pressurized air to which the turbine was subjected. Platinum thin-film heat flux gages were used to obtain the heat flux measurements, while miniature silicon-diaphragm flush-mounted pressure transducers were used to obtain the pressure measurements. The first stage vane Stanton number distributions are compared with predictions obtained using a version of STAN5 and a quasi-3D Navier-Stokes solution. This same quasi-3D N-S code was also used to obtain predictions for the first blade and the second vane.

Control of nasal vasculature and airflow resistance in the dog.

PubMed Central

Lung, M A; Phipps, R J; Wang, J C; Widdicombe, J G

1984-01-01

Nasal vascular and airflow resistances have been measured in dogs, simultaneously on both sides separately. Vascular resistance was measured either by constant flow perfusion of the terminal branch of the maxillary artery (which supplies, via the sphenopalatine artery, the nasal septum, most of the turbinates and the nasal sinuses) or by measuring blood flow through this artery, maintained by the dog's own blood pressure. Airflow resistance was assessed by inserting balloon-tipped endotracheal catheters into the back of each nasal cavity via the nasopharynx, and measuring transnasal pressure at constant airflow through each side of the nose simultaneously. Preliminary experiments indicated that there was 5-10% collateral anastomosis between the two sides. Close-arterial injection of drugs showed different patterns of response. Adrenaline, phenylephrine, chlorpheniramine and low doses of prostaglandin F2 alpha increased vascular resistance and lowered airway resistance. Salbutamol, methacholine and histamine lowered vascular resistance and increased airway resistance. Dobutamine decreased airway resistance with a small increase in vascular resistance. Prostaglandins E1, E2 and F2 alpha (high dose) decreased both vascular and airway resistances. Substance P, eledoisin-related peptide and vasoactive intestinal polypeptide lowered vascular resistance with little change in airway resistance. The results are interpreted in terms of possible drug actions on precapillary resistance vessels, sinusoids and venules, and arteriovenous anastomoses. It is concluded that nasal airway resistance cannot be correlated with vascular resistance or blood flow, since the latter has a complex and ill-defined relationship with nasal vascular blood volume. PMID:6204040

Control of nasal vasculature and airflow resistance in the dog.

PubMed

Lung, M A; Phipps, R J; Wang, J C; Widdicombe, J G

1984-04-01

Nasal vascular and airflow resistances have been measured in dogs, simultaneously on both sides separately. Vascular resistance was measured either by constant flow perfusion of the terminal branch of the maxillary artery (which supplies, via the sphenopalatine artery, the nasal septum, most of the turbinates and the nasal sinuses) or by measuring blood flow through this artery, maintained by the dog's own blood pressure. Airflow resistance was assessed by inserting balloon-tipped endotracheal catheters into the back of each nasal cavity via the nasopharynx, and measuring transnasal pressure at constant airflow through each side of the nose simultaneously. Preliminary experiments indicated that there was 5-10% collateral anastomosis between the two sides. Close-arterial injection of drugs showed different patterns of response. Adrenaline, phenylephrine, chlorpheniramine and low doses of prostaglandin F2 alpha increased vascular resistance and lowered airway resistance. Salbutamol, methacholine and histamine lowered vascular resistance and increased airway resistance. Dobutamine decreased airway resistance with a small increase in vascular resistance. Prostaglandins E1, E2 and F2 alpha (high dose) decreased both vascular and airway resistances. Substance P, eledoisin-related peptide and vasoactive intestinal polypeptide lowered vascular resistance with little change in airway resistance. The results are interpreted in terms of possible drug actions on precapillary resistance vessels, sinusoids and venules, and arteriovenous anastomoses. It is concluded that nasal airway resistance cannot be correlated with vascular resistance or blood flow, since the latter has a complex and ill-defined relationship with nasal vascular blood volume.

Phase-Imaging with a Sharpened Multi-Walled Carbon Nanotube AFM Tip: Investigation of Low-k Dielectric Polymer Hybrids

NASA Technical Reports Server (NTRS)

Nguyen, Cattien V.; Stevens, Ramsey M.; Meyyappan, M.; Volksen, Willi; Miller, Robert D.

2005-01-01

Phase shift tapping mode scanning force microscopy (TMSFM) has evolved into a very powerful technique for the nanoscale surface characterization of compositional variations in heterogeneous samples. Phase shift signal measures the difference between the phase angle of the excitation signal and the phase angle of the cantilever response. The signal correlates to the tip-sample inelastic interactions, identifying the different chemical and/or physical property of surfaces. In general, the resolution and quality of scanning probe microscopic images are highly dependent on the size of the scanning probe tip. In improving AFM tip technology, we recently developed a technique for sharpening the tip of a multi-walled carbon nanotube (CNT) AFM tip, reducing the radius of curvature of the CNT tip to less than 5 nm while still maintaining the inherent stability of multi-walled CNT tips. Herein we report the use of sharpened (CNT) AFM tips for phase-imaging of polymer hybrids, a precursor for generating nanoporous low-k dielectrics for on-chip interconnect applications. Using sharpened CNT tips, we obtained phase-contrast images having domains less than 10 nm. In contrast, conventional Si tips and unsharpened CNT tips (radius greater than 15 nm) were not able to resolve the nanoscale domains in the polymer hybrid films. C1early, the size of the CNT tip contributes significantly to the resolution of phase-contrast imaging. In addition, a study on the nonlinear tapping dynamics of the multi-walled CNT tip indicates that the multi-walled CNT tip is immune to conventional imaging instabilities related to the coexistence of attractive and repulsive tapping regimes. This factor may also contribute to the phase-contrast image quality of multi-walled CNT AFM tips. This presentation will also offer data in support of the stability of the CNT tip for phase shift TMSFM.

Trafficking and Health: A Systematic Review of Research Methods.

PubMed

Cannon, Abby C; Arcara, Jennet; Graham, Laurie M; Macy, Rebecca J

2018-04-01

Trafficking in persons (TIP) is a human rights violation with serious public health consequences. Unfortunately, assessing TIP and its health sequelae rigorously and reliably is challenging due to TIP's clandestine nature, variation in definitions of TIP, and the need to use research methods that ensure studies are ethical and feasible. To help guide practice, policy, and research to assess TIP and health, we undertook a systematic literature review of 70 peer-reviewed, published articles to (a) identify TIP and health research methods being used, (b) determine what we can learn about TIP and health from these varied methodologies, and (c) determine the gaps that exist in health-focused TIP research. Results revealed that there are various quantitative and qualitative data collection and analysis methods being used to investigate TIP and health. Furthermore, findings show that the limitations of current methodologies affect what is known about TIP and health. In particular, varying definitions, participant recruitment strategies, ethical standards, and outcome measures all affect what is known about TIP and health. Moreover, findings demonstrate an urgent need for representative and nonpurposive recruitment strategies in future investigations of TIP and health as well as research on risk and protective factors related to TIP and health, intervention effectiveness, long-term health outcomes, and research on trafficked people beyond women trafficked for sex. We offer recommendations for research, policy, and practice based on review results.

[Results after distraction arthroplasty according to Bufalini and Perugia in early stages of trapeziometacarpal osteoarthritis].

PubMed

Fatzer, Lukas; Soleman, E; Sanchez, T

2015-02-01

A distraction arthroplasty of the trapeziometacarpal joint was introduced by Bufalini and Perugia for the treatment of the early stages of carpometacarpal osteoarthritis. Our retrospective study presents the results of this technique. Thereby, a tendon graft anchored to the distal second metacarpal is fixed at the base of the first metacarpal, keeping it in distraction. 10 distraction arthroplasties were performed in 9 patients with carpometacarpal osteoarthritis stage I and II of the thumb after unsuccessful conservative therapy. In 2 cases, which were excluded from our study, trapeziectomy had to be performed because of persisting pain. Patient satisfaction, pain measurement, range of motion, and tip, key and grip strength were evaluated at a follow-up of 46.5 (29-63) months in the remaining 7 patients (8 operations overall). Strengh measurement was taken in an absolute value and compared to the opposite side. Thumb range of motion was measured with the combined flexion-opposition of the thumb with the Kapandij index and also the angle of abduction of the metacarpal I to metacarpal II. Assessment included a DASH score evaluation and an X-ray control. All of the 7 evaluated patients were satisfied with the operation results. Compared to the opposite side, patients achieved 80.1% (5.9 kg±1.1 kg) of key pinch strength, 86.3% (4.8 kg±0.9 kg) of oppositional tip pinch strength, and 86.1% (23.1 kg±4.8 kg) of grip strength. In combined flexion and opposition a Kapandij index of 8.5 (94.4%) compared to 9 on the opposite side was achieved. Thumb radial abduction was 48.2°±2.8°, compared to 51.0°±2.9° on the contralateral hand. At follow-up, the mean DASH score was 17.8 (±10.0). Radiological control showed no progression of carpometacarpal osteoarthritis of the thumb. The collected data after distraction arthroplasty according to Bufalini and Perugia confirm the efficacy of the technique in the early stage of carpometacarpal osteoarthritis of the thumb. Even though a failure rate of 20% occurred, in our opinion the operation is justified in the early stages of carpometacarpal osteoarthritis of the thumb as the patients benefit from a pain-free interval, leaving the option for future trapeziectomy. © Georg Thieme Verlag KG Stuttgart · New York.

Efficacy of four different irrigation techniques combined with 60 °C 3% sodium hypochlorite and 17% EDTA in smear layer removal.

PubMed

Guo, Xiangjun; Miao, Hui; Li, Lei; Zhang, Shasha; Zhou, Dongyan; Lu, Yan; Wu, Ligeng

2014-09-08

Efforts to improve the efficacy of smear layer removal by applying irrigant activation at the final irrigation or by elevating the temperature of the irrigant have been reported. However, the combination of such activation protocols with 60 °C 3% sodium hypochlorite (NaOCl) has seldom been mentioned. The aim of this study was to compare the efficacy in smear layer removal of four different irrigation techniques combined with 60 °C 3% NaOCl and 17% EDTA. Fifty single-rooted teeth were randomly divided into five groups (n = 10) according to the irrigant agitation protocols used during chemomechanical preparation(Dentsply Maillefer, Ballaigues, Switzerland): a side-vented needle group, a ultrasonic irrigation (UI) group, a NaviTip FX group, an EndoActivator group, and a control group (no agitation). After each instrumentation, the root canals were irrigated with 1 mL of 3% NaOCl at 60 °C for 1 minute, and after the whole instrumentation, the root canals were rinsed with 1 mL of 17% EDTA for 1 minute. Both NaOCl and EDTA were activated with one of the five irrigation protocols. The efficacy of smear layer removal was scored at the apical, middle and coronal thirds. The Data were statistically analyzed using SAS version 9.2 for Windows (rank sum test for a randomised block design and ANOVA). No significant differences among the NaviTip FX group, EndoActivator group and control groups, and each of these groups showed a lower score than that of UI group (P < 0.05). Within each group, all three thirds were ranked in the following order: coronal > middle > apical (P < 0.05). In the coronal third, the NaviTip FX group was better than UI group. In the middle and apical third, the differences were not significant among any of the groups. Even without any activation, the combination of 60 °C 3% NaOCl and 17% EDTA could remove the smear layer effectively, similar to NaviTip FX or EndoActivator, and these three protocols were more effective than UI. However, regardless of different types of irrigation technique applied, complete removal of the smear layer was not achieved, particularly in the apical third.

Moons Around Saturn

NASA Technical Reports Server (NTRS)

1996-01-01

This series of 10 Hubble Space Telescope images captures several small moons orbiting Saturn. Hubble snapped the five pairs of images while the Earth was just above the ring plane and the Sun below it. The telescope captured a pair of images every 97 minutes as it circled the Earth. Moving out from Saturn, the visible rings are: the broad C Ring, the Cassini Division, and the narrow F Ring.

The first pair of images shows the large, bright moon Dione, near the middle of the frames. Two smaller moons, Pandora (the brighter one closer to Saturn) and Prometheus, appear as if they're touching the F Ring. In the second frame, Mimas emerges from Saturn's shadow and appears to be chasing Prometheus.

In the second image pair, Mimas has moved towards the tip of the F Ring. Rhea, another bright moon, has just emerged from behind Saturn. Prometheus, the closest moon to Saturn, has rounded the F Ring's tip and is approaching the planet. The slightly larger moon Epimetheus has appeared.

The third image pair shows Epimetheus, as a tiny dot just beyond the tip of the F Ring. Prometheus is in the lower right corner. An elongated clump or arc of debris in the F ring is seen as a slight brightening on the far side of this thin ring.

In the fourth image pair, Epimetheus, in the lower right corner, streaks towards Saturn. The long ring arc can be seen in both frames.

The fifth image pair again captures Mimas, beyond the tip of the F Ring. The same ring arc is still visible.

In addition to the satellites, a pair of stars can be seen passing behind the rings, appearing to move towards the lower left due to Saturn's motion across the sky.

The images were taken Nov. 21, 1995 with Wide Field Planetary Camera-2.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

Molecular genetic investigations of root gravitropism and other complex growth behaviors using Arabidopsis and Brachypodium as models

NASA Astrophysics Data System (ADS)

Masson, Patrick; Barker, Richard; Miller, Nathan; Su, Shih-Hao; Su, Shih-Heng

2016-07-01

When growing on hard surfaces, Arabidopsis roots tend to grown downward, as dictated by positive gravitropism. At the same time, surface-derived stimuli promote a wavy pattern of growth that is superimposed to a rightward root-skewing trend. This behavior is believed to facilitate obstacle avoidance in soil. To better understand these complex behaviors, we have isolated and characterized mutations that affect them. Some of these mutations were shown to affect gravitropism whereas others did not. Within the latter group, most of the mutations affected mechanisms that control anisotropic cell expansion. We have also characterized mutations that affect early steps of gravity signal transduction within the gravity-sensing columella cells of the root cap. Upon reorientation within the gravity field, starch-filled plastids sediment to the bottom-side of these cells, triggering a pathway that leads to re-localization of auxin efflux facilitators to the bottom membrane. Lateral auxin transport toward the bottom flank ensues, leading to gravitropic curvature. Several of the mutations we characterized affect genes that encode proteins associated with the vesicle trafficking pathway needed for this cell polarization. Other mutations were shown to affect components of the plastid outer envelope protein import complex (TOC). Their functional analysis suggests an active role for plastids in gravity signal transduction, beyond a simple contribution as sedimenting gravity susceptors. Because most cultivated crops are monocots, not dicots like Arabidopsis, we have also initiated studies of root-growth behavior with Brachypodium distachyon. When responding to a gravistimulus, the roots of Brachypodium seedlings develop a strong downward curvature that proceeds until the tip reaches a ~50-degree curvature. At that time, an oscillatory tip movement occurs while the root continues its downward reorientation. These root-tip oscillations also occur if roots are allowed to simply grow downward on vertical surfaces, or fully embedded in agar-containing medium. Brachypodium distachyon accessions differ in their gravisensitivity, kinetics of gravitropism and occurrence, periodicity and amplitude of tip oscillations. Mathematical models are being built to fit the data, and used to estimate growth, gravitropism and oscillation parameters for incorporation into Genome-Wide Association Study (GWAS) algorithms aimed at identifying contributing loci. This work was supported by grants from the National Aeronautics and Space Administration (NASA) and from the National Science Foundation (NSF).

Theoretical Study of tip apex electronic structure in Scanning Tunneling Microscope

NASA Astrophysics Data System (ADS)

Choi, Heesung; Huang, Min; Randall, John; Cho, Kyeongjae

2011-03-01

Scanning Tunneling Microscope (STM) has been widely used to explore diverse surface properties with an atomic resolution, and STM tip has played a critical role in controlling surface structures. However, detailed information of atomic and electronic structure of STM tip and the fundamental understanding of STM images are still incomplete. Therefore, it is important to develop a comprehensive understanding of the electronic structure of STM tip. We have studied the atomic and electronic structures of STM tip with various transition metals (TMs) by DFT method. The d-electrons of TM tip apex atoms show different orbital states near the Fermi level. We will present comprehensive data of STM tips from our DFT calculation. Verified quantification of the tip electronic structures will lead to fundamental understanding of STM tip structure-property relationship. This work is supported by the DARPA TBN Program and the Texas ETF. DARPA Tip Based Nanofabrication Program and the Emerging Technology Fund of the State of Texas.

Integrated Turbine Tip Clearance and Gas Turbine Engine Simulation

NASA Technical Reports Server (NTRS)

Chapman, Jeffryes W.; Kratz, Jonathan; Guo, Ten-Huei; Litt, Jonathan

2016-01-01

Gas turbine compressor and turbine blade tip clearance (i.e., the radial distance between the blade tip of an axial compressor or turbine and the containment structure) is a major contributing factor to gas path sealing, and can significantly affect engine efficiency and operational temperature. This paper details the creation of a generic but realistic high pressure turbine tip clearance model that may be used to facilitate active tip clearance control system research. This model uses a first principles approach to approximate thermal and mechanical deformations of the turbine system, taking into account the rotor, shroud, and blade tip components. Validation of the tip clearance model shows that the results are realistic and reflect values found in literature. In addition, this model has been integrated with a gas turbine engine simulation, creating a platform to explore engine performance as tip clearance is adjusted. Results from the integrated model explore the effects of tip clearance on engine operation and highlight advantages of tip clearance management.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schürpf, Thomas; Chen, Qiang; Liu, Jin-huan

Developmental endothelial cell locus-1 (Del-1) glycoprotein is secreted by endothelial cells and a subset of macrophages. Del-1 plays a regulatory role in vascular remodeling and functions in innate immunity through interaction with integrin {alpha}{sub V}{beta}{sub 3}. Del-1 contains 3 epidermal growth factor (EGF)-like repeats and 2 discoidin-like domains. An Arg-Gly-Asp (RGD) motif in the second EGF domain (EGF2) mediates adhesion by endothelial cells and phagocytes. We report the crystal structure of its 3 EGF domains. The RGD motif of EGF2 forms a type II' {beta} turn at the tip of a long protruding loop, dubbed the RGD finger. Whereas EGF2more » and EGF3 constitute a rigid rod via an interdomain calcium ion binding site, the long linker between EGF1 and EGF2 lends considerable flexibility to EGF1. Two unique O-linked glycans and 1 N-linked glycan locate to the opposite side of EGF2 from the RGD motif. These structural features favor integrin binding of the RGD finger. Mutagenesis data confirm the importance of having the RGD motif at the tip of the RGD finger. A database search for EGF domain sequences shows that this RGD finger is likely an evolutionary insertion and unique to the EGF domain of Del-1 and its homologue milk fat globule-EGF 8. The RGD finger of Del-1 is a unique structural feature critical for integrin binding.« less

The Vortex Lattice Method for the Rotor-Vortex Interaction Problem

NASA Technical Reports Server (NTRS)

Padakannaya, R.

1974-01-01

The rotor blade-vortex interaction problem and the resulting impulsive airloads which generate undesirable noise levels are discussed. A numerical lifting surface method to predict unsteady aerodynamic forces induced on a finite aspect ratio rectangular wing by a straight, free vortex placed at an arbitrary angle in a subsonic incompressible free stream is developed first. Using a rigid wake assumption, the wake vortices are assumed to move downsteam with the free steam velocity. Unsteady load distributions are obtained which compare favorably with the results of planar lifting surface theory. The vortex lattice method has been extended to a single bladed rotor operating at high advance ratios and encountering a free vortex from a fixed wing upstream of the rotor. The predicted unsteady load distributions on the model rotor blade are generally in agreement with the experimental results. This method has also been extended to full scale rotor flight cases in which vortex induced loads near the tip of a rotor blade were indicated. In both the model and the full scale rotor blade airload calculations a flat planar wake was assumed which is a good approximation at large advance ratios because the downwash is small in comparison to the free stream at large advance ratios. The large fluctuations in the measured airloads near the tip of the rotor blade on the advance side is predicted closely by the vortex lattice method.

[Z2 appliance: the pre-adjusted appliance based on Chinese normal occlusion].

PubMed

Zeng, Xiang-long; Gao, Xue-mei

2008-12-01

Z2 appliance is the pre-adjusted appliance designed for Chinese orthodontic patients. The prescription of the appliance is based on Chinese normal occlusion, which is much different from the West in the first and the second orders as well as the third one. The appliance routinely includes 20 brackets and 8 molar buccal tubers with 3 standard arch forms. Clinically, continued light force is used in whole treatment. The side-effects such as forward tipping of incisors, bite deepening and loss of molar anchorage are reduced further due to fewer tips built into the anterior brackets as well as lower friction elastometric modules used during aligning and leveling. In condition of arch are leveled completely, 0.48 mm x 0.64 mm stainless steel archwire with 1.47 N retraction force is the best combination for sliding mechanics, which is proved by 3D nonlinear finite element study. Self drilling micro-screw is used for maximum anchorage. In finishing stage 0.53 mm x 0.64 mm NT arch wire is added in order to get full torque expressing. The research of Chinese pre-adjusted appliance has been lasted for more than 10 years in the department and clinical studies on Z2 appliance show that with minimal wire bending, treatment is more efficient and result is high quality and more consistent for Chinese orthodontic patients.

Potential in vivo UVC disinfection of catheter lumens: estimation of the doses received by the blood flow outside the catheter tip hole.

PubMed

Bak, Jimmy; Jørgensen, Thomas M; Helfmann, Jurgen; Gravemann, Ute; Vorontsova, Inessa

2011-01-01

We have demonstrated that it is possible to launch UVC LED light into bacterial contaminated polymer tubes/catheters and disinfect the intraluminal space of these tubes. This can be achieved by UVC treatment of the catheters on a regular basis. Catheters are in the distal end equipped with an exit hole for administration of drugs, bloods or nutrients into the bloodstream. Even if the UVC light is strongly attenuated during its propagation through the catheter tube a fraction of the UVC launched into the catheter will escape through the exit hole and irradiate the blood. We demonstrate by calculations that very small effective doses are exposed to the blood (ca 10(-4) J m(-2)). This dosage level is very low compared with UVC doses reported from other therapeutic applications. The very short residence time of the blood constituents in the irradiated volume in front of the exit hole is the main reason why the UVC exposure to the blood in the catheter application is so low. The very low dose received by the blood through the catheter tip indicated that possible side effects are negligible and makes the UV disinfection technique feasible in a clinical setting. © 2011 Jimmy Bak. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Fusion of deformed nuclei in the reactions of 76Ge+150Nd and 28Si+198Pt at the Coulomb barrier region

NASA Astrophysics Data System (ADS)

Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Lu, J.

2000-07-01

Evaporation residue cross sections for 28Si+198Pt and 76Ge+150Nd, both of which form a compound nucleus 226U, were measured in the vicinity of the Coulomb barrier. The measurement gives direct evidence that the system really fuses together to form a fully equilibrated compound nucleus. For the 28Si+198Pt reaction, we have measured the fission fragments to determine the fusion cross section by taking advantage of the highly fissile character of 226U. The evaporation residue cross section and the fusion cross section for 28Si+198Pt allowed us to investigate the deexcitation process (exit channel) of the compound nucleus 226U, and the parameters entering in a statistical model calculation could be determined. By estimating the deexcitation of the compound nucleus 226U with the statistical model, the effect of the deformed nucleus 150Nd on the fusion reaction 76Ge+150Nd was extracted. The experimental data indicated that there is more than 13 MeV extra-extra-push energy for the system to fuse together when the projectile 76Ge collides at the tip of the deformed 150Nd nucleus. On the contrary, for the side collision which is more compact in configuration than the tip collision, no fusion hindrance is suggested.

Balance in Representation - More Than One Way to Tip the Scales

NASA Astrophysics Data System (ADS)

Rowell, D. S.; Carlis, D. L.

2017-12-01

Too often diversity balance is seen as purely a numbers issue - one of influx and totals. And thus recruiting and retention being two sides of the same valuable coin. However, balance is not just numbers. There is more than one means to add diversity value to an organization. Numbers is one, but power is another. `Balance' is also reached through empowerment and voice. Whereas recruiting and retention can be seen as hard currency buying balanced demographics, empowerment is an investment that takes various forms and yields various dividends. Empowerment includes investment in people, and training, and systems, and pays dividends in performance, and voice, and careers, and service. In this way space is created for the benefits of diversity even where numbers and composition is statically unyielding. Equilibrium comes from tipping the scales with involvement, impact and affect. And finally in coming back full circle, empowerment has a bonus direct effect on the numbers, as it does improve diverse recruiting and retention. This presentation places a focus on balance in terms of gender efficacy. It will highlight the requirements to grow and mature gender empowerment investments and show how these investments have diversity dividends. And finally the presentation will note how NWS is taking a multi-faceted approach to diversity to achieve `balance' through empowerment, involvement, (gender) mainstreaming, training, etc…, and of course recruiting and retention.

Observations on the Growth of Roughness Elements Into Icing Feathers

NASA Technical Reports Server (NTRS)

Vargas, Mario; Tsao, Jen, Ching

2007-01-01

This work presents the results of an experiment conducted in the Icing Research Tunnel at NASA Glenn Research Center to understand the process by which icing feathers are formed in the initial stages of ice accretion formation on swept wings. Close-up photographic data were taken on an aluminum NACA 0012 swept wing tip airfoil. Two types of photographic data were obtained: time sequence close-up photographic data during the run and close-up photographic data of the ice accretion at the end of each run. Icing runs were conducted for short ice accretion times from 10 to 180 sec. The time sequence close-up photographic data was used to study the process frame by frame and to create movies of how the process developed. The movies confirmed that at glaze icing conditions in the attachment line area icing feathers develop from roughness elements. The close-up photographic data at the end of each run showed that roughness elements change into a pointed shape with an upstream facet and join on the side with other elements having the same change to form ridges with pointed shape and upstream facet. The ridges develop into feathers when the upstream facet grows away to form the stem of the feather. The ridges and their growth into feathers were observed to form the initial scallop tips present in complete scallops.

Tips of the dual-lumen microcatheter-facilitated reverse wire technique in percutaneous coronary interventions for markedly angulated bifurcated lesions.

PubMed

Nomura, Tetsuya; Kikai, Masakazu; Hori, Yusuke; Yoshioka, Kenichi; Kubota, Hiroshi; Miyawaki, Daisuke; Urata, Ryota; Sugimoto, Takeshi; Keira, Natsuya; Tatsumi, Tetsuya

2018-04-01

In practical settings of percutaneous coronary intervention (PCI), we sometimes encounter difficulty in introducing a guidewire (GW) to the markedly angulated side branch (SB), and the reverse wire technique is considered as a last resort to overcome such a situation. We analyzed 12 cases that underwent PCI with dual-lumen microcatheter-facilitated reverse wire technique between January 2013 and July 2016. We retrospectively investigated the lesion's characteristics and the details of the PCI procedures, and discussed tips about the use of this technique. The SB that exhibits both a smaller take-off angle and a larger carina angle is considered to be the most suitable candidate for this technique. The first step of this technique involves the delivery of the reverse wire system to the target bifurcation. However, most cases exhibit significant stenosis proximal to the bifurcation, which often hampers the delivery of the reverse wire system. Because the sharply curved reverse wire system is easier to pass the stenosis as compared to the roundly curved system, we recommend a sharp curve should be adopted for this technique. On the other hand, it is sure that device delivery is much easier on the GW with a round curve as compared to that with a sharp curve. Therefore, it is important to modify the details of this procedure on a case-by-case basis according to the lesion's characteristics.

Investigation of the shape transferability of nanoscale multi-tip diamond tools in the diamond turning of nanostructures

NASA Astrophysics Data System (ADS)

Luo, Xichun; Tong, Zhen; Liang, Yingchun

2014-12-01

In this article, the shape transferability of using nanoscale multi-tip diamond tools in the diamond turning for scale-up manufacturing of nanostructures has been demonstrated. Atomistic multi-tip diamond tool models were built with different tool geometries in terms of the difference in the tip cross-sectional shape, tip angle, and the feature of tool tip configuration, to determine their effect on the applied forces and the machined nano-groove geometries. The quality of machined nanostructures was characterized by the thickness of the deformed layers and the dimensional accuracy achieved. Simulation results show that diamond turning using nanoscale multi-tip tools offers tremendous shape transferability in machining nanostructures. Both periodic and non-periodic nano-grooves with different cross-sectional shapes can be successfully fabricated using the multi-tip tools. A hypothesis of minimum designed ratio of tool tip distance to tip base width (L/Wf) of the nanoscale multi-tip diamond tool for the high precision machining of nanostructures was proposed based on the analytical study of the quality of the nanostructures fabricated using different types of the multi-tip tools. Nanometric cutting trials using nanoscale multi-tip diamond tools (different in L/Wf) fabricated by focused ion beam (FIB) were then conducted to verify the hypothesis. The investigations done in this work imply the potential of using the nanoscale multi-tip diamond tool for the deterministic fabrication of period and non-periodic nanostructures, which opens up the feasibility of using the process as a versatile manufacturing technique in nanotechnology.

Ergonomic factors related to drop-off detection with the long cane: effects of cane tips and techniques.

PubMed

Kim, Dae Shik; Emerson, Robert S Wall; Curtis, Amy B

2010-06-01

This study examined the effect of cane tips and cane techniques on drop-off detection with the long cane. Blind pedestrians depend on a long cane to detect drop-offs. Missing a drop-off may result in falls or collision with moving vehicles in the street. Although cane tips appear to affect a cane user's ability to detect drop-offs, few experimental studies have examined such effect. A repeated-measures design with block randomization was used for the study. Participants were 17 adults who were legally blind and had no other disabilities. Participants attempted to detect the drop-offs of varied depths using different cane tips and cane techniques. Drop-off detection rates were similar between the marshmallow tip (77.0%) and the marshmallow roller tip (79.4%) when both tips were used with the constant contact technique, p = .294. However, participants detected drop-offs at a significantly higher percentage when they used the constant contact technique with the marshmallow roller tip (79.4%) than when they used the two-point touch technique with the marshmallow tip (63.2%), p < .001. The constant contact technique used with a marshmallow roller tip (perceived as a less advantageous tip) was more effective than the two-point touch technique used with a marshmallow tip (perceived as a more advantageous tip) in detecting drop-offs. The findings of the study may help cane users and orientation and mobility specialists select appropriate cane techniques and cane tips in accordance with the cane user's characteristics and the nature of the travel environment.