Specific minor groove solvation is a crucial determinant of DNA binding site recognition

PubMed Central

Harris, Lydia-Ann; Williams, Loren Dean; Koudelka, Gerald B.

2014-01-01

The DNA sequence preferences of nearly all sequence specific DNA binding proteins are influenced by the identities of bases that are not directly contacted by protein. Discrimination between non-contacted base sequences is commonly based on the differential abilities of DNA sequences to allow narrowing of the DNA minor groove. However, the factors that govern the propensity of minor groove narrowing are not completely understood. Here we show that the differential abilities of various DNA sequences to support formation of a highly ordered and stable minor groove solvation network are a key determinant of non-contacted base recognition by a sequence-specific binding protein. In addition, disrupting the solvent network in the non-contacted region of the binding site alters the protein's ability to recognize contacted base sequences at positions 5–6 bases away. This observation suggests that DNA solvent interactions link contacted and non-contacted base recognition by the protein. PMID:25429976

Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

NASA Technical Reports Server (NTRS)

Ream, L. W.

1974-01-01

A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

Mark-forming simulations of phase-change land/groove disks

NASA Astrophysics Data System (ADS)

Nishi, Yoshiko; Shimano, Takeshi; Kando, Hidehiko

2000-09-01

The track pitches of optical discs have become so narrow that it is comparable to the wavelength of laser beam. Finite-difference time-domain (FDTD) simulation, based on vector diffraction analysis, can predict the propagation of light more accurately than scalar analysis, when the size of media texture becomes sub-micron order. The authors applied FDTD simulation to land-and-groove optical disc models, and found out that the effects of 3D geometry is not negligible in analyzing the energy absorption of light inside the land- and-groove multi-layered media. The electromagnetic field in the media does not have the same intensity distribution as the incident beam. Furthermore, the heat conduction inside the media depends on the disc geometry, so the beam spots centered on land and groove makes different effects in heating the recording layers. That is, the spatial and historical profile of temperature requires 3D analysis for both incident light absorption and heat conduction. The difference in temperature profiles is applied to the phase change simulator to see the writing process of the marks in land and groove. We have integrated three simulators: FDTD analysis, heat conduction and phase change simulation. These simulators enabled to evaluate the differences in mark forming process between land and groove.

Tunable THz notch filter with a single groove inside parallel-plate waveguides.

PubMed

Lee, Eui Su; Jeon, Tae-In

2012-12-31

A single groove in a parallel-plate waveguide (PPWG) has been applied to a tunable terahertz (THz) notch filter with a transverse-electromagnetic (TEM) mode. When the air gap between the metal plates of the PPWG is controlled from 60 to 240 μm using a motor controlled translation stage or a piezo-actuator, the resonant frequency of the notch filter is changed from 1.75 up to 0.62 THz, respectively. Therefore, the measured tunable sensitivity of the notch filter increases to 6.28 GHz/μm. The measured resonant frequencies were found to be in good agreement with the calculation using an effective groove depth. Using a finite-difference time-domain (FDTD) simulation, we also demonstrate that the sensitivity of a THz microfluidic sensor can be increased via a small air gap, a narrow groove width, and a deep groove depth.

A Precise Visual Method for Narrow Butt Detection in Specular Reflection Workpiece Welding

PubMed Central

Zeng, Jinle; Chang, Baohua; Du, Dong; Hong, Yuxiang; Chang, Shuhe; Zou, Yirong

2016-01-01

During the complex path workpiece welding, it is important to keep the welding torch aligned with the groove center using a visual seam detection method, so that the deviation between the torch and the groove can be corrected automatically. However, when detecting the narrow butt of a specular reflection workpiece, the existing methods may fail because of the extremely small groove width and the poor imaging quality. This paper proposes a novel detection method to solve these issues. We design a uniform surface light source to get high signal-to-noise ratio images against the specular reflection effect, and a double-line laser light source is used to obtain the workpiece surface equation relative to the torch. Two light sources are switched on alternately and the camera is synchronized to capture images when each light is on; then the position and pose between the torch and the groove can be obtained nearly at the same time. Experimental results show that our method can detect the groove effectively and efficiently during the welding process. The image resolution is 12.5 μm and the processing time is less than 10 ms per frame. This indicates our method can be applied to real-time narrow butt detection during high-speed welding process. PMID:27649173

A Precise Visual Method for Narrow Butt Detection in Specular Reflection Workpiece Welding.

PubMed

Zeng, Jinle; Chang, Baohua; Du, Dong; Hong, Yuxiang; Chang, Shuhe; Zou, Yirong

2016-09-13

During the complex path workpiece welding, it is important to keep the welding torch aligned with the groove center using a visual seam detection method, so that the deviation between the torch and the groove can be corrected automatically. However, when detecting the narrow butt of a specular reflection workpiece, the existing methods may fail because of the extremely small groove width and the poor imaging quality. This paper proposes a novel detection method to solve these issues. We design a uniform surface light source to get high signal-to-noise ratio images against the specular reflection effect, and a double-line laser light source is used to obtain the workpiece surface equation relative to the torch. Two light sources are switched on alternately and the camera is synchronized to capture images when each light is on; then the position and pose between the torch and the groove can be obtained nearly at the same time. Experimental results show that our method can detect the groove effectively and efficiently during the welding process. The image resolution is 12.5 μm and the processing time is less than 10 ms per frame. This indicates our method can be applied to real-time narrow butt detection during high-speed welding process.

Approximation of super-ions for single-file diffusion of multiple ions through narrow pores.

PubMed

Kharkyanen, Valery N; Yesylevskyy, Semen O; Berezetskaya, Natalia M

2010-11-01

The general theory of the single-file multiparticle diffusion in the narrow pores could be greatly simplified in the case of inverted bell-like shape of the single-particle energy profile, which is often observed in biological ion channels. There is a narrow and deep groove in the energy landscape of multiple interacting ions in such profiles, which corresponds to the pre-defined optimal conduction pathway in the configurational space. If such groove exists, the motion of multiple ions can be reduced to the motion of single quasiparticle, called the superion, which moves in one-dimensional effective potential. The concept of the superions dramatically reduces the computational complexity of the problem and provides very clear physical interpretation of conduction phenomena in the narrow pores.

Safety Grooving

NASA Technical Reports Server (NTRS)

1985-01-01

Safety grooving, the cutting of grooves in concrete to increase traction and prevent injury, was first developed to reduce aircraft accidents on wet runways. Represented by the International Grooving and Grinding Association (IG&GA), the industry expanded into highway and pedestrian applications. The technique originated at Langley, which assisted in testing the grooving at airports and on highways. Skidding was reduced, stopping distance decreased, and a vehicle's cornering ability on curves was increased. The process has been extended to animal holding pens, steps, parking lots and other potentially slippery surfaces.

Structural analysis of the binding modes of minor groove ligands comprised of disubstituted benzenes

PubMed Central

Hawkins, Cheryl A.; Watson, Charles; Yan, Yinfa; Gong, Bing; Wemmer, David E.

2001-01-01

Two-dimensional homonuclear NMR was used to characterize synthetic DNA minor groove-binding ligands in complexes with oligonucleotides containing three different A-T binding sites. The three ligands studied have a C2 axis of symmetry and have the same general structural motif of a central para-substituted benzene ring flanked by two meta-substituted rings, giving the molecules a crescent shape. As with other ligands of this shape, specificity seems to arise from a tight fit in the narrow minor groove of the preferred A-T-rich sequences. We found that these ligands slide between binding subsites, behavior attributed to the fact that all of the amide protons in the ligand backbone cannot hydrogen bond to the minor groove simultaneously. PMID:11160926

NMR studies of DNA oligomers and their interactions with minor groove binding ligands

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

Fagan, Patricia A.

1996-05-01

The cationic peptide ligands distamycin and netropsin bind noncovalently to the minor groove of DNA. The binding site, orientation, stoichiometry, and qualitative affinity of distamycin binding to several short DNA oligomers were investigated by NMR spectroscopy. The oligomers studied contain A,T-rich or I,C-rich binding sites, where I = 2-desaminodeoxyguanosine. I•C base pairs are functional analogs of A•T base pairs in the minor groove. The different behaviors exhibited by distamycin and netropsin binding to various DNA sequences suggested that these ligands are sensitive probes of DNA structure. For sites of five or more base pairs, distamycin can form 1:1 or 2:1more » ligand:DNA complexes. Cooperativity in distamycin binding is low in sites such as AAAAA which has narrow minor grooves, and is higher in sites with wider minor grooves such as ATATAT. The distamycin binding and base pair opening lifetimes of I,C-containing DNA oligomers suggest that the I,C minor groove is structurally different from the A,T minor groove. Molecules which direct chemistry to a specific DNA sequence could be used as antiviral compounds, diagnostic probes, or molecular biology tools. The author studied two ligands in which reactive groups were tethered to a distamycin to increase the sequence specificity of the reactive agent.« less

Experimental Studies on Grooved Double Pipe Heat Exchanger with Different Groove Space

NASA Astrophysics Data System (ADS)

Sunu, P. W.; Arsawan, I. M.; Anakottapary, D. S.; Santosa, I. D. M. C.; Yasa, I. K. A.

2018-01-01

Experimental studies were performed on grooved double pipe heat exchanger (DPHE) with different groove space. The objective of this work is to determine optimal heat transfer parameter especially logarithmic mean temperature difference (LMTD). The document in this paper also provides the total heat observed by the cold fluid. The rectangular grooves were incised on outer surface of tube side with circumferential pattern and two different grooves space, namely 1 mm and 2 mm. The distance between grooves and the grooves high were kept constant, 8 mm and 0.3 mm respectively. The tube diameter is 20 mm and its made of aluminium. The shell is made of acrylic which has 28 mm in diameter. Water is used as the working fluid. Using counter flow scheme, the cold fluid flows in the annulus room of DPHE. The volume flowrate of hot fluid remains constant at 15 lpm. The volume flowrate of cold fluid were varied from 11 lpm to 15 lpm. Based on logarithmic mean temperature difference analysis, the LMTD of 1 mm grooves space was higher compared to that of 2 mm grooves space. The smaller grooves space has more advantage since the recirculating region are increased which essentially cause larger heat transfer enhancement.

Development of spiral-groove self-acting face seals

NASA Technical Reports Server (NTRS)

Obrien, M.

1977-01-01

An experimental evaluation and a 100-hour endurance test were performed on a spiral groove geometry, self-acting face seal. The seal was tested and operated successfully at maximum conditions of 243.8 m/s surface speed, 199.9 N/sq cm air pressure, and 645.4K (702 F) air temperature. The maximum speed condition of 243.8 m/s was obtained at a shaft speed of 72,500 rpm. Seal wear, gas leakage, and sealing element temperature were monitored during the test. Condition of the seal at the completion of the test was documented and found acceptable for further use. The spiral groove wear rate measured during the endurance test indicates a minimum potential seal life of over 2700 hours. Seal air leakage measured during the test program is within the range considered acceptable for consideration for use in a small gas turbine engine.

Multiphysics Modeling of a Single Channel in a Nuclear Thermal Propulsion Grooved Ring Fuel Element

NASA Technical Reports Server (NTRS)

Kim, Tony; Emrich, William J., Jr.; Barkett, Laura A.; Mathias, Adam D.; Cassibry, Jason T.

2013-01-01

In the past, fuel rods have been used in nuclear propulsion applications. A new fuel element concept that reduces weight and increases efficiency uses a stack of grooved discs. Each fuel element is a flat disc with a hole on the interior and grooves across the top. Many grooved ring fuel elements for use in nuclear thermal propulsion systems have been modeled, and a single flow channel for each design has been analyzed. For increased efficiency, a fuel element with a higher surface-area-to-volume ratio is ideal. When grooves are shallower, i.e., they have a lower surface area, the results show that the exit temperature is higher. By coupling the physics of turbulence with those of heat transfer, the effects on the cooler gas flowing through the grooves of the thermally excited solid can be predicted. Parametric studies were done to show how a pressure drop across the axial length of the channels will affect the exit temperatures of the gas. Geometric optimization was done to show the behaviors that result from the manipulation of various parameters. Temperature profiles of the solid and gas showed that more structural optimization is needed to produce the desired results. Keywords: Nuclear Thermal Propulsion, Fuel Element, Heat Transfer, Computational Fluid Dynamics, Coupled Physics Computations, Finite Element Analysis

Effects of gap width on droplet transfer behavior in ultra-narrow gap laser welding of high strength aluminum alloys

NASA Astrophysics Data System (ADS)

Song, Chaoqun; Dong, Shiyun; Yan, Shixing; He, Jiawu; Xu, Binshi; He, Peng

2017-10-01

Ultra-narrow gap laser welding is a novel method for thick high strength aluminum alloy plate for its lower heat input, less deformation and higher efficiency. To obtain a perfect welding quality, it is vital to control the more complex droplet transfer behavior under the influence of ultra-narrow gap groove. This paper reports the effects of gap width of groove on droplet transfer behavior in ultra-narrow gap laser welding of 7A52 aluminum alloy plates by a high speed camera, using an ER 5356 filler wire. The results showed that the gap width had directly effects on droplet transfer mode and droplet shape. The droplet transfer modes were, in order, both-sidewall transfer, single-sidewall transfer, globular droplet transfer and bridging transfer, with different droplet shape and transition period, as the gap width increased from 2 mm to 3.5mm. The effect of gap width on lack of fusion was also studied to analyze the cause for lack of fusion at the bottom and on the sidewall of groove. Finally, with a 2.5 mm U-type parallel groove, a single-pass joint with no lack of fusion and other macro welding defects was successfully obtained in a single-sidewall transfer mode.

Narrow Groove and Restricted Anchors of MHC Class I Molecule BF2*0401 Plus Peptide Transporter Restriction can Explain Disease Susceptibility of B4 Chickens

PubMed Central

Zhang, Jianhua; Chen, Yong; Qi, Jianxun; Gao, Feng; Liu, Yanjie; Liu, Jun; Zhou, Xuyu; Kaufman, Jim; Xia, Chun; Gao, George F.

2016-01-01

The major histocompatibility complex (MHC) has genetic associations with many diseases, often due to differences in presentation of antigenic peptides by polymorphic MHC molecules to T lymphocytes of the immune system. In chickens, only a single classical class I molecule in each MHC haplotype is expressed well due to co-evolution with the polymorphic transporters associated with antigen presentation (TAPs), which means that resistance and susceptibility to infectious pathogens are particularly easy to observe. Previously, structures of chicken MHC class I molecule BF2*2101 from B21 haplotype showed an unusually large peptide-binding groove that accommodates a broad spectrum of peptides to present as epitopes to cytotoxic T lymphocytes (CTL), explaining the MHC-determined resistance of B21 chickens to Marek's disease. Here, we report the crystal structure of BF2*0401 from the B4 (also known as B13) haplotype, showing a highly positively-charged surface hitherto unobserved in other MHC molecules, as well as a remarkably narrow groove due to the allele-specific residues with bulky side chains. Together, these properties limit the number of epitope peptides that can bind this class I molecule. However, peptide-binding assays show that in vitro BF2*0401 can bind a wider variety of peptides than are found on the surface of B4 cells. Thus, a combination of the specificities of the polymorphic TAP transporter and the MHC results in a very limited set of BF2*0401 peptides with negatively charged anchors to be presented to T lymphocytes. PMID:23041567

Selective CO2 gas adsorption in the narrow crystalline cavities of flexible peptide metallo-macrocycles.

PubMed

Miyake, Ryosuke; Kuwata, Chika; Masumoto, Yui

2015-02-21

Crystalline peptide Ni(ii)-macrocycles (BF4(-) salt) exhibited moderate CO2 gas adsorption (ca. 6-7 CO2 molecules per macrocycle) into very narrow cavities (narrowest part <2 Å), accompanied by the expansion of the cavities. The BF4(-) salt demonstrated selective uptake of CO2 gas in preference to CH4 and N2 gases.

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, Barry L.

1998-01-01

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

Groove refinishing tool

DOEpatents

Kellogg, Harvey J.; Holm, Robert O.

1983-01-01

A groove refinishing tool which utilizes a finishing wheel which is controlled by an air grinder motor. The air grinder motor is mounted on a main body section which is pivotally attached to a shoe element. The shoe element contains guide pins which guide the shoe element on the groove to be refinished. Application of pressure on the main body element compresses a weight counterbalance spring to extend the finishing wheel through the shoe element to refinish the groove surface. A window is provided for viewing the refinishing operation. Milling operations can also be performed by replacing the finishing wheel with a milling wheel.

Hall thruster with grooved walls

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

Li Hong; Ning Zhongxi; Yu Daren

2013-02-28

Axial-oriented and azimuthal-distributed grooves are formed on channel walls of a Hall thruster after the engine undergoes a long-term operation. Existing studies have demonstrated the relation between the grooves and the near-wall physics, such as sheath and electron near-wall transport. The idea to optimize the thruster performance with such grooves was also proposed. Therefore, this paper is devoted to explore the effects of wall grooves on the discharge characteristics of a Hall thruster. With experimental measurements, the variations on electron conductivity, ionization distribution, and integrated performance are obtained. The involved physical mechanisms are then analyzed and discussed. The findings helpmore » to not only better understand the working principle of Hall thruster discharge but also establish a physical fundamental for the subsequent optimization with artificial grooves.« less

Spectral analysis of groove spacing on Ganymede

NASA Technical Reports Server (NTRS)

Grimm, R. E.; Squyres, S. W.

1985-01-01

A quantitative analysis of groove spacing on Ganymede is described. Fourier transforms of a large number of photometric profiles across groove sets are calculated and the resulting power spectra are examined for the position and strength of peaks representing topographic periodicities. The geographic and global statistical distribution of groove wavelengths are examined, and these data are related to models of groove tectonism. It is found that groove spacing on Ganymede shows an approximately long-normal distribution with a minimum of about 3.5 km, a maximum of about 17 km, and a mean of 8.4 km. Groove spacing tends to be quite regular within a single groove set but can vary substantially from one groove set to another within a single geographic region.

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, B.L.

1998-10-27

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

Local-scale stratigraphy of grooved terrain on Ganymede

NASA Technical Reports Server (NTRS)

Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

1987-01-01

The surface of the Jovian satellite, Ganymede, is divided into two main units, dark terrain cut by arcuate and subradial furrows, and light terrain consisting largely of areas with pervasive U-shaped grooves. The grooved terrain may be subdivided on the basis of pervasive morphology of groove domains into four terrain types: (1) elongate bands of parallel grooves (groove lanes); (2) polygonal domains of parallel grooves (grooved polygons); (3) polygonal domains of two orthogonal groove sets (reticulate terrain); and (4) polygons having two to several complexly cross-cutting groove sets (complex grooved terrain). Reticulate terrain is frequently dark and not extensively resurfaced, and grades to a more hummocky terrain type. The other three grooved terrain types have almost universally been resurfaced by light material during their emplacement. The sequence of events during grooved terrain emplacement has been investigated. An attempt is made to integrate observed geologic and tectonic patterns to better constrain the relative ages and styles of emplacement of grooved terrain types. A revised model of grooved terrain emplacement is proposed and is tested using detailed geologic mapping and measurement of crater density.

Dielectric image line groove antennas for millimeterwaves

NASA Astrophysics Data System (ADS)

Solbach, K.; Wolff, I.

Grooves in the ground plane of dielectric image lines are proposed as a new radiating structure. A figure is included showing the proposed groove structure as a discontinuity in a dielectric image line. A wave incident on the dielectric image line is partly reflected by the discontinuity, partly transmitted across the groove, and partly radiated into space above the line. In a travelling-wave antenna, a number of grooves are arranged below a dielectric guide, with spacings around one guide wavelength to produce a beam in the upper half space. A prescribed aperture distribution can be effected by tapering the series radiation resistance of the grooves. This can be done by adjusting the depths of the grooves with a constant width or by varying the widths of the grooves with a constant depth. Attention is also given to circular grooves. Here, the widths of the holes are chosen so that they can be considered as waveguides operating far below the cut-off frequency of the fundamental circular waveguide mode.

Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

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

Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif

2012-09-26

Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotipsmore » can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 {mu}m. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 {mu}m can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.« less

Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts

NASA Technical Reports Server (NTRS)

Dirusso, E.

1983-01-01

A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter-rotating hafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 psi) absolute and temperatures from 95 deg to 327 C (203 deg to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines.

Influence of musical groove on postural sway.

PubMed

Ross, Jessica M; Warlaumont, Anne S; Abney, Drew H; Rigoli, Lillian M; Balasubramaniam, Ramesh

2016-03-01

Timescales of postural fluctuation reflect underlying neuromuscular processes in balance control that are influenced by sensory information and the performance of concurrent cognitive and motor tasks. An open question is how postural fluctuations entrain to complex environmental rhythms, such as in music, which also vary on multiple timescales. Musical groove describes the property of music that encourages auditory-motor synchronization and is used to study voluntary motor entrainment to rhythmic sounds. The influence of groove on balance control mechanisms remains unexplored. We recorded fluctuations in center of pressure (CoP) of standing participants (N = 40) listening to low and high groove music and during quiet stance. We found an effect of musical groove on radial sway variability, with the least amount of variability in the high groove condition. In addition, we observed that groove influenced postural sway entrainment at various temporal scales. For example, with increasing levels of groove, we observed more entrainment to shorter, local timescale rhythmic musical occurrences. In contrast, we observed more entrainment to longer, global timescale features of the music, such as periodicity, with decreasing levels of groove. Finally, musical experience influenced the amount of postural variability and entrainment at local and global timescales. We conclude that groove in music and musical experience can influence the neural mechanisms that govern balance control, and discuss implications of our findings in terms of multiscale sensorimotor coupling. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

First branchial groove anomaly.

PubMed

Kumar, M; Hickey, S; Joseph, G

2000-06-01

First branchial groove anomalies are very rare. We report a case of a first branchial groove anomaly presented as an infected cyst in an 11-month-old child. Management of such lesions is complicated because of their close association with the facial nerve. Surgical management must include identification and protection of the facial nerve. Embryology and facial nerve disposition in relation to the anomaly are reviewed.

Development of spiral-groove self-acting seals for helicopter engines

NASA Technical Reports Server (NTRS)

Obrien, M.

1979-01-01

A spiral-groove, self-acting face seal was rig tested at advanced gas turbine operating conditions to determine wear and leakage rates. The spiral-groove, self-acting geometry was located in the rotating seal seat. Seal component wear induced by start-stop operation was measured after subjecting the test seal to 176 start-stop cycles. Wear occurring during normal operation was documented throughout a 75-hour endurance test. Seal air leakage was also measured. During endurance operation, the seal was subjected to operating conditions bounded by the values surface speed - 244 m/s (800 ft/sec), air pressure - 148 N/sq cm abs (215 psia), and air temperature - 622 K (660 F). The post-test condition of the seal components was documented. Wear data is presented in tabular form, while seal air leakage is presented graphically, as a function of pressure and speed.

Numerical analysis of flow in a centrifugal compressor with circumferential grooves: influence of groove location and number on flow instability

NASA Astrophysics Data System (ADS)

Chen, X.; Qin, G.; Ai, Z.; Ji, Y.

2017-08-01

As an effective and economic method for flow range enhancement, circumferential groove casing treatment (CGCT) is widely used to increase the stall margin of compressors. Different from traditional grooved casing treatments, in which the grooves are always located over the rotor in both axial and radial compressors, one or several circumferential grooves are located along the shroud side of the diffuser passage in this paper. Numerical investigations were conducted to predict the performance of a low flow rate centrifugal compressor with CGCT in diffuser. Computational fluid dynamics (CFD) analysis is performed under stage environment in order to find the optimum location of the circumferential casing groove in consideration of stall margin enhancement and efficiency gain at design point, and the impact of groove number to the effect of this grooved casing treatment configuration in enhancing the stall margin of the compressor stage is studied. The results indicate that the centrifugal compressor with circumferential groove in vaned diffuser can obtain obvious improvement in the stall margin with sacrificing design efficiency a little. Efforts were made to study blade level flow mechanisms to determine how the CGCT impacts the compressor’s stall margin (SM) and performance. The flow structures in the passage, the tip gap, and the grooves as well as their mutual interactions were plotted and analysed.

MR imaging of apparent 3He gas transport in narrow pipes and rodent airways

NASA Astrophysics Data System (ADS)

Minard, Kevin R.; Jacob, Richard E.; Laicher, Gernot; Einstein, Daniel R.; Kuprat, Andrew P.; Corley, Richard A.

2008-10-01

High sensitivity makes hyperpolarized 3He an attractive signal source for visualizing gas flow with magnetic resonance (MR) imaging. Its rapid Brownian motion, however, can blur observed flow lamina and alter measured diffusion rates when excited nuclei traverse shear-induced velocity gradients during data acquisition. Here, both effects are described analytically, and predicted values for measured transport during laminar flow through a straight, 3.2-mm diameter pipe are validated using two-dimensional (2D) constant-time images of different binary gas mixtures. Results show explicitly how measured transport in narrow conduits is characterized by apparent values that depend on underlying gas dynamics and imaging time. In ventilated rats, this is found to obscure acquired airflow images. Nevertheless, flow splitting at airway branches is still evident and use of 3D vector flow mapping is shown to reveal surprising detail that highlights the correlation between gas dynamics and lung structure.

Discovery of Grooves on Gaspra

USGS Publications Warehouse

Veverka, J.; Thomas, P.; Simonelli, D.; Belton, M.J.S.; Carr, M.; Chapman, C.; Davies, M.E.; Greeley, R.; Greenberg, R.; Head, J.; Klaasen, K.; Johnson, T.V.; Morrison, D.; Neukum, G.

1994-01-01

We report the discovery of grooves in Galileo high-resolution images of Gaspra. These features, previously seen only on Mars' satellite Phobos, are most likely related to severe impacts. Grooves on Gaspra occur as linear and pitted depressions, typically 100-200 m wide, 0.8 to 2.5 km long, and 10-20 m deep. Most occur in two major groups, one of which trends approximately parallel to the asteroid's long axis, but is offset by some 15??; the other is approximately perpendicular to this trend. The first of these directions falls along a family of planes which parallel three extensive flat facets identified by Thomas et al., Icarus 107. The occurrence of grooves on Gaspra is consistent with other indications (irregular shape, cratering record) that this asteroid has evolved through a violent collisional history. The bodywide congruence of major groove directions and other structural elements suggests that present-day Gaspra is a globally coherent body. ?? 1994 Academic Press. All rights reserved.

Terrain types and local-scale stratigraphy of grooved terrain on ganymede

NASA Technical Reports Server (NTRS)

Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

1986-01-01

Grooved terrain is subdivided on the basis of pervasive morphology into: (1) groove lanes - elongate parallel groove bands, (2) grooved polygons - polygonal domains of parallel grooves, (3) reticulate terrain - polygonal domains of orthogonal grooves, and (4) complex grooved terrain - polygons with several complexly cross-cutting groove sets. Detailed geologic mapping of select areas, employing previously established conventions for determining relative age relations, reveals a general three-stage sequence of grooved terrain emplacement: first, dissection of the lithosphere by throughgoing grooves, and pervasive deformation of intervening blocks; second, extensive flooding and continued deformation of the intervening blocks; third, repeated superposition of groove lanes concentrated at sites of initial throughgoing grooves. This sequence is corroborated by crater-density measurements. Dominant orientations of groove sets are parallel to relict zones of weakness that probably were reactivated during grooved terrain formation. Groove lane morphology and development consistent with that predicted for passive rifts suggests a major role of global expansion in grooved terrain formation.

High Precision 2-D Grating Groove Density Measurement

NASA Astrophysics Data System (ADS)

Zhang, Ningxiao; McEntaffer, Randall; Tedesco, Ross

2017-08-01

Our research group at Penn State University is working on producing X-ray reflection gratings with high spectral resolving power and high diffraction efficiency. To estimate our fabrication accuracy, we apply a precise 2-D grating groove density measurement to plot groove density distributions of gratings on 6-inch wafers. In addition to plotting a fixed groove density distribution, this method is also sensitive to measuring the variation of the groove density simultaneously. This system can reach a measuring accuracy (ΔN/N) of 10-3. Here we present this groove density measurement and some applications.

Droplet impact on regular micro-grooved surfaces

NASA Astrophysics Data System (ADS)

Hu, Hai-Bao; Huang, Su-He; Chen, Li-Bin

2013-08-01

We have investigated experimentally the process of a droplet impact on a regular micro-grooved surface. The target surfaces are patterned such that micro-scale spokes radiate from the center, concentric circles, and parallel lines on the polishing copper plate, using Quasi-LIGA molding technology. The dynamic behavior of water droplets impacting on these structured surfaces is examined using a high-speed camera, including the drop impact processes, the maximum spreading diameters, and the lengths and numbers of fingers at different values of Weber number. Experimental results validate that the spreading processes are arrested on all target surfaces at low velocity. Also, the experimental results at higher impact velocity demonstrate that the spreading process is conducted on the surface parallel to the micro-grooves, but is arrested in the direction perpendicular to the micro-grooves. Besides, the lengths of fingers increase observably, even when they are ejected out as tiny droplets along the groove direction, at the same time the drop recoil velocity is reduced by micro-grooves which are parallel to the spreading direction, but not by micro-grooves which are vertical to the spreading direction.

Double-grooved nanofibre surfaces with enhanced anisotropic hydrophobicity.

PubMed

Liang, Meimei; Chen, Xin; Xu, Yang; Zhu, Lei; Jin, Xiangyu; Huang, Chen

2017-11-02

This study reports a facile method for fabricating double-grooved fibrous surfaces. The primary grooves of the surface are formed by aligned fibres, while the secondary grooves are achieved by oriented nanogrooves on the fibre surface. Investigation into the formation mechanism reveals that the nanogrooves can be readily tailored through adjusting the solvent ratio and relative humidity. With this understanding, a variety of polymers have been successfully electrospun into fibres having the same nanogrooved feature. These fibres show high resemblance to natural hierarchical structures, and thereby endowing the corresponding double-grooved surface with enhanced anisotropic hydrophobicity. A water droplet at a parallel direction to the grooves exhibits a much higher contact angle and a lower roll-off angle than the droplet at a perpendicular direction. The application potential of such anisotropic hydrophobicity has been demonstrated via a fog collection experiment, in which the double-grooved surface can harvest the largest amount of water. Moreover, the fabrication method requires neither post-treatment nor sophisticated equipment, making us anticipate that the double-grooved surface would be competitive in areas where a highly ordered surface, a large surface area and an anisotropic hydrophobicity are preferred.

Solar cell with doped groove regions separated by ridges

DOEpatents

Molesa, Steven Edward; Pass, Thomas; Kraft, Steve

2017-01-31

Solar cells with doped groove regions separated by ridges and methods of fabricating solar cells are described. In an example, a solar cell includes a substrate having a surface with a plurality of grooves and ridges. A first doped region of a first conductivity type is disposed in a first of the grooves. A second doped region of a second conductivity type, opposite the first conductivity type, is disposed in a second of the grooves. The first and second grooves are separated by one of the ridges.

Transmission characteristics of a subwavelength metallic slit with perpendicular groove

NASA Astrophysics Data System (ADS)

Jin, Li; Zhou, Jun; Zou, Weibo; Zhang, Haopeng; Zhang, Lingfen

2011-12-01

The transmission property of a subwavelength metallic slit with perpendicular groove is investigated by using finite element method. The lengths for the slits at both sides of the groove are set as the length of a metallic slit without groove at the surface plasmon fundamental mode resonance. In the grooved subwavelength metallic slit, enhanced transmission is found to be attributed to two kinds of resonance including surface plasmon waveguide resonance along the propagating direction and the transversely constructive interferential resonance. For the former resonance, integer antinodes of surface plasmon are formed in the groove. For the later resonance, there is a tradeoff between the maximum amplitude and the full width at half maximum of the transmitted peaks with the change of the groove width. And, the transmission enhancement of the grooved subwavelength metallic slit is related to the number of groove and the incident wavelength. Furthermore, the above resonances also exist in the structure whose lengths of metallic slits are set as the length of a slit without groove at the surface plasmon high-order mode resonance. By optimizing the geometric parameters, the transmission enhancement of the grooved subwavelength metallic slit as high as about 15367% is achieved.

Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts. [o ring seals

NASA Technical Reports Server (NTRS)

Dirusso, E.

1983-01-01

A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter rotating shafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 psi) absolute and temperatures from 95 to 327 C (203 to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines.

Edge seal for a porous gas distribution plate of a fuel cell

DOEpatents

Feigenbaum, Haim; Pudick, Sheldon; Singh, Rajindar

1984-01-01

In an improved seal for a gas distribution plate of a fuel cell, a groove is provided extending along an edge of the plate. A member of resinous material is arranged within the groove and a paste comprising an immobilized acid is arranged surrounding the member and substantially filling the groove. The seal, which is impervious to the gas being distributed, is resistant to deterioration by the electrolyte of the cell.

Axially grooved heat pipe study

NASA Technical Reports Server (NTRS)

1977-01-01

A technology evaluation study on axially grooved heat pipes is presented. The state-of-the-art is reviewed and present and future requirements are identified. Analytical models, the Groove Analysis Program (GAP) and a closed form solution, were developed to facilitate parametric performance evaluations. GAP provides a numerical solution of the differential equations which govern the hydrodynamic flow. The model accounts for liquid recession, liquid/vapor shear interaction, puddle flow as well as laminar and turbulent vapor flow conditions. The closed form solution was developed to reduce computation time and complexity in parametric evaluations. It is applicable to laminar and ideal charge conditions, liquid/vapor shear interaction, and an empirical liquid flow factor which accounts for groove geometry and liquid recession effects. The validity of the closed form solution is verified by comparison with GAP predictions and measured data.

Micrometer for Measuring Trepanned Grooves

NASA Technical Reports Server (NTRS)

Bird, S. K.

1983-01-01

Special micrometer measures diameter of circular groove on face of large part, while part is mounted in lathe chuck. Tool has curved frame so it can reach around obstruction on centerline of part. At one end of frame is blade/ micrometer spindle for reaching into groove to be measured; this type of spindle does not rotate when micrometer thimble is turned in taking measurement. Other end of frame has sliding foot with blade.

Spectral analysis of groove spacing on Ganymede

NASA Technical Reports Server (NTRS)

Grimm, R. E.

1984-01-01

The technique used to analyze groove spacing on Ganymede is presented. Data from Voyager images are used determine the surface topography and position of the grooves. Power spectal estimates are statistically analyzed and sample data is included.

Imaging spectrophotometry of ionized gas in NGC 1068. I - Kinematics of the narrow-line region

NASA Technical Reports Server (NTRS)

Cecil, Gerald; Bland, Jonathan; Tully, R. Brent

1990-01-01

The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis.

Capillary Contact Angle in a Completely Wet Groove

NASA Astrophysics Data System (ADS)

Parry, A. O.; Malijevský, A.; Rascón, C.

2014-10-01

We consider the phase equilibria of a fluid confined in a deep capillary groove of width L with identical side walls and a bottom made of a different material. All walls are completely wet by the liquid. Using density functional theory and interfacial models, we show that the meniscus separating liquid and gas phases at two phase capillary coexistence meets the bottom capped end of the groove at a capillary contact angle θcap(L) which depends on the difference between the Hamaker constants. If the bottom wall has a weaker wall-fluid attraction than the side walls, then θcap>0 even though all the isolated walls are themselves completely wet. This alters the capillary condensation transition which is now first order; this would be continuous in a capped capillary made wholly of either type of material. We show that the capillary contact angle θcap(L) vanishes in two limits, corresponding to different capillary wetting transitions. These occur as the width (i) becomes macroscopically large, and (ii) is reduced to a microscopic value determined by the difference in Hamaker constants. This second wetting transition is characterized by large scale fluctuations and essential critical singularities arising from marginal interfacial interactions.

Resistance of full veneer metal crowns with different forms of axial grooves

NASA Astrophysics Data System (ADS)

Hidayat, A. S.; Masulili, C.; Indrasari, M.

2017-08-01

Dental crowns or bridges can occasionally come loose or separate from the tooth during chewing, particularly when they are situated on small, short, and conical teeth. The main cause of this separation is a lack of retention and resistance to the tooth. There are several methods available to increase the retention and resistance of the crown during both inlay and onlay preparation, including parallelism, groove preparation, crown build-up, and surface roughness. The aim of this study was to determine the differences in resistance of full veneer metal crowns with various forms of groove preparation. The study involved the compressive strength testing of a total of 24 specimens, namely six specimens without groove preparation, six specimens with box-shaped grooves, six specimens with V-shaped grooves, and six specimens with half round grooves. The mean values of the metal crowns that separated from the teeth during testing were 27.97 ± 1.08 kgF for the crowns with box-shaped grooves, 6.15 ± 0.22 kgF for those with V-shaped grooves, 1.77 ± 0.12 kgF for those with half round grooves, and 0.95 ± 0.13 kgF for those without grooves. This study found that the resistance is best in crowns with box-shaped grooves, followed by those with V-shaped grooves, half round grooves, and those without groove. When clinicians are working on short and conical molar teeth, it is therefore recommended that box-shaped grooves are used to increase the resistance of the crown.

Realizing structural color generation with aluminum plasmonic V-groove metasurfaces

DOE PAGES

Wang, Wei; Rosenmann, Daniel; Czaplewski, David A.; ...

2017-08-14

The structural color printing based on all-aluminum plasmonic V-groove metasurfaces is demonstrated under both bright field and dark field illumination conditions. A broad visible color range is realized with the plasmonic V-groove arrays etched on aluminum surface by simply varying the groove depth while keeping the groove period as a constant. Polarization dependent structural color printing is further achieved with interlaced V-groove arrays along both the horizontal and vertical directions. Furthermore, these results pave the way towards the use of all-aluminum structural color printing platform for many practical applications such as security marking and information storage.

Realizing structural color generation with aluminum plasmonic V-groove metasurfaces

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

Wang, Wei; Rosenmann, Daniel; Czaplewski, David A.

The structural color printing based on all-aluminum plasmonic V-groove metasurfaces is demonstrated under both bright field and dark field illumination conditions. A broad visible color range is realized with the plasmonic V-groove arrays etched on aluminum surface by simply varying the groove depth while keeping the groove period as a constant. Polarization dependent structural color printing is further achieved with interlaced V-groove arrays along both the horizontal and vertical directions. Furthermore, these results pave the way towards the use of all-aluminum structural color printing platform for many practical applications such as security marking and information storage.

Spiral groove seal. [for rotating shaft

NASA Technical Reports Server (NTRS)

Ludwig, L. P.; Strom, T. N. (Inventor)

1974-01-01

Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove produces a pumping action toward the fluid when the shaft rotates. This prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear. Provision is made for placing these spiral grooves in communication with the fluid to accelerate the generation of the hydraulic lifting force.

Plasma interaction with emmissive surface with Debye-scale grooves

NASA Astrophysics Data System (ADS)

Schweigert, Irina; Burton, Thomas S.; Thompson, Gregory B.; Langendorf, Samuel; Walker, Mitchell L. R.; Keidar, Michael

2018-04-01

The sheath development over emissive grooved surface in dc discharge plasma controlled by an electron beam is studied in the experiment and in 2D kinetic simulations. Grooved hexagonal boron nitride surfaces with different aspect ratios, designed to mimic the erosion channels, were exposed to an argon plasma. The characteristic size of the grooves (1 mm and 5 mm) is about of the Debye length. The secondary electrons emission from the grooved surfaces is provided by the bombardment with energetic electrons originated from the heated powered cathode. The transition between a developed and a collapsed sheaths near emissive surface takes place with an increase of the beam electron energy. For grooved emissive surfaces, the sheath transition happens at essentially higher voltage compared to the planar one. This phenomenon is analyzed in the terms of the electron energy distribution function.

Strike-Slip Faulting Processes on Ganymede: Global Morphological Mapping and Structural Interpretation of Grooved and Transitional Terrains

NASA Astrophysics Data System (ADS)

Burkhard, L. M.; Cameron, M. E.; Smith-Konter, B. R.; Seifert, F.; Pappalardo, R. T.; Collins, G. C.

2015-12-01

Ganymede's fractured surface reveals many large-scale, morphologically distinct regions of inferred distributed shear and strike-slip faulting that may be important to the structural development of its surface and in the transition from dark to light (grooved) materials. To better understand the role of strike-slip tectonism in shaping Ganymede's complex icy surface, we perform a detailed mapping of key examples of strike-slip morphologies (i.e., en echelon structures, strike-slip duplexes, laterally offset pre-existing features, and possible strained craters) from Galileo and Voyager images. We focus on complex structures associated with grooved terrain (e.g. Nun Sulcus, Dardanus Sulcus, Tiamat Sulcus, and Arbela Sulcus) and terrains transitional from dark to light terrain (e.g. the boundary between Nippur Sulcus and Marius Regio, including Byblus Sulcus and Philus Sulcus). Detailed structural interpretations suggest strong evidence of strike-slip faulting in some regions (i.e., Nun and Dardanus Sulcus); however, further investigation of additional strike-slip structures is required of less convincing regions (i.e., Byblus Sulcus). Where applicable, these results are synthesized into a global database representing an inferred sense of shear for many of Ganymede's fractures. Moreover, when combined with existing observations of extensional features, these results help to narrow down the range of possible principal stress directions that could have acted at the regional or global scale to produce grooved terrain on Ganymede.

Femtosecond laser-induced blazed periodic grooves on metals.

PubMed

Hwang, Taek Yong; Guo, Chunlei

2011-07-01

In this Letter, we generate laser-induced periodic surface structures (LIPSSs) on platinum following femtosecond laser pulse irradiation. For the first time to our knowledge, we study the morphological profile of LIPSSs over a broad incident angular range, and find that the morphological profile of LIPSSs depends significantly on the incident angle of the laser beam. We show that LIPSS grooves become more asymmetric at a larger incident angle, and the morphological profile of LIPSSs formed at an incident angle over 55° eventually resembles that of a blazed grating. Our study suggests that the formation of the blazed groove structures is attributed to the selective ablation of grooves through the asymmetric periodic surface heating following femtosecond pulse irradiation. The blazed grooves are useful for controlling the diffraction efficiency of LIPSSs.

Testing of a single graded groove variable conductance heat pipe

NASA Astrophysics Data System (ADS)

Kapolnek, Michael R.; Holmes, H. R.; Hager, Brian

1992-07-01

Variable conductance heat pipes (VCHPs) with transport capacities in the 50,000 to 100,000 Watt-inch range will be required to transport the large heat loads anticipated for advanced spacecraft. A high-reliability, nonarterial constant conductance heat pipe with this capacity, the Single Graded Groove (SGG) heat pipe, was developed for NASA's Space Station Freedom. The design and testing of a variable conductance SGG heat pipe are described. Response of the pipe to startup and heat load changes was excellent. After correcting for condenser temperature changes, the evaporator temperature varied by only +/- 4 F for large evaporator heat load changes. The surface tension difference between ends of the gas blocked region was found to measurably affect the performance of the pipe. Performance was negligibly affected by Marangoni flow in the gas blocked region.

The Formation of Ganymede's Grooved Terrain: Importance of Strain Weakening

NASA Astrophysics Data System (ADS)

Bland, M. T.; McKinnon, W. B.; Showman, A. P.

2008-12-01

Nearly two-thirds of Ganymede's surface consists of relatively bright, young, tectonically deformed terrain dubbed grooved terrain. The grooved terrain consists of sets of parallel, undulatory ridges and troughs with peak to trough amplitudes of several hundred meters and periodic spacings that range from 3 to 10~km. The low slopes and periodic spacing of the grooves suggest that they formed via unstable extension of the ice lithosphere [e.g. Fink and Fletcher 1981, LPS XII; Pappalardo et al. 1998, Icarus 135]. Application of analytical models of unstable extension to Ganymede suggest that large amplitude grooves with appropriate wavelengths can form if the lithosphere is in pervasive brittle failure and if the lithospheric thermal gradient was relatively high (~45K km-1) [Dombard and McKinnon 2001, Icarus 154]; however, numerical models of unstable extension struggle to produce topographic amplitudes consistent with Ganymede's grooves (maximum amplitudes are a factor of five less than typical large amplitude grooves) [Bland and Showman 2007, Icarus 189]. The difficulties in producing large amplitude deformation may be overcome by the inclusion of strain weakening in models of groove formation. Strain weakening effects account for a material's tendency to strain more easily as viscous and/or plastic deformation accumulates, and as strain localizes in shear zones or along faults. When included in models of terrestrial extension, such effects can increase deformation amplitudes by up to several orders of magnitude [e.g. Fredericksen and Braun 2001, EPSL 188; Behn et al. 2002, EPSL 202]. Here we present the results of simulations of Ganymede's groove formation that include various strain weakening processes. Incorporation of a simple damage rheology, in which the yield strength of the ice lithosphere decreases as plastic strain accumulates, permits a factor of three increase in the amplitude of the simulated grooves, generating topography of 200~m or more. Such groove

Experimental investigation of turbulent flow in smooth and longitudinal grooved tubes

NASA Technical Reports Server (NTRS)

Nitschke, P.

1984-01-01

Turbulent flow in tubes with and without longitudinal grooves is examined. The discovery of fine grooves forming a sort of streamline pattern on the body of sharks led to the expectation that the grooves on a surface reduce the momentum change, and thus the drag. To test this thesis, drag law, velocity profile and the profile of the velocity fluctuation were determined. Results show that for moderate Reynolds numbers the drag coefficient for grooved tubes is about 3 percent smaller than that of the smooth tubes. At higher Reynolds numbers, however, the drag coefficient for grooved tubes becomes larger than that for smooth tubes. No significant differences in the velocity profiles between grooved tubes and smooth tubes are found.

Flow visualization study of grooved surface/surfactant/air sheet interaction

NASA Technical Reports Server (NTRS)

Reed, Jason C.; Weinstein, Leonard M.

1989-01-01

The effects of groove geometry, surfactants, and airflow rate have been ascertained by a flow-visualization study of grooved-surface models which addresses the possible conditions for skin friction-reduction in marine vehicles. It is found that the grooved surface geometry holds the injected bubble stream near the wall and, in some cases, results in a 'tube' of air which remains attached to the wall. It is noted that groove dimension and the use of surfactants can substantially affect the stability of this air tube; deeper grooves, surfactants with high contact angles, and angled air injection, are all found to increase the stability of the attached air tube, while convected disturbances and high shear increase interfacial instability.

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.

Static and dynamic characteristics of parallel-grooved seals

NASA Technical Reports Server (NTRS)

Iwatsubo, Takuzo; Yang, Bo-Suk; Ibaraki, Ryuji

1987-01-01

Presented is an analytical method to determine static and dynamic characteristics of annular parallel-grooved seals. The governing equations were derived by using the turbulent lubrication theory based on the law of fluid friction. Linear zero- and first-order perturbation equations of the governing equations were developed, and these equations were analytically investigated to obtain the reaction force of the seals. An analysis is presented that calculates the leakage flow rate, the torque loss, and the rotordynamic coefficients for parallel-grooved seals. To demonstrate this analysis, we show the effect of changing number of stages, land and groove width, and inlet swirl on stability of the boiler feed water pump seals. Generally, as the number of stages increased or the grooves became wider, the leakage flow rate and rotor-dynamic coefficients decreased and the torque loss increased.

Grooved Fuel Rings for Nuclear Thermal Rocket Engines

NASA Technical Reports Server (NTRS)

Emrich, William

2009-01-01

An alternative design concept for nuclear thermal rocket engines for interplanetary spacecraft calls for the use of grooved-ring fuel elements. Beyond spacecraft rocket engines, this concept also has potential for the design of terrestrial and spacecraft nuclear electric-power plants. The grooved ring fuel design attempts to retain the best features of the particle bed fuel element while eliminating most of its design deficiencies. In the grooved ring design, the hydrogen propellant enters the fuel element in a manner similar to that of the Particle Bed Reactor (PBR) fuel element.

Grooved Terrain on Ganymede: A Galileo-based Synthesis

NASA Technical Reports Server (NTRS)

Pappalardo, Robert T.; Collins, Geoffrey C.; Head, James W.; Moore, Jeffrey M.; Schenk, Paul M.

2003-01-01

Swaths of bright "grooved terrain" (sulci) on Ganymede are 10s to 100s of kilometers wide and cross-cut the older dark terrain, forming an intricate patchwork across 2/3 of Ganymede's surface. The view of grooved terrain developed from Voyager images is that bright cells are broad graben infilled by extrusion of relatively clean (silicate-poor) liquid water, warm ice, or icy slush, and then extended and faulted. Galileo imaging has greatly improved understanding of the emplacement history and geological implications of grooved terrain, supporting a rift-like model for its formation.

The influence of mixture composition, adhesion promotor and compaction degree on the groove stability of grooved Marshall asphalt

NASA Astrophysics Data System (ADS)

Vuye, Cedric; Couscheir, Karolien; Lauriks, Leen; Van den bergh, Wim; Van Bouwel, Philippe

2017-09-01

After the first rehabilitation of runway 07R/25L in 2015, runway 01/19 was reconstructed in the summer of 2016, as part of a cycle where all runway pavements at Brussels airport are completely renovated each thirty years. The top layer is a Marshall asphalt with a polymer modified bitumen. To optimize the water drainage the central part of the runway (47 m wide) is grooved instead of applying an anti-skid layer. In this paper the focus is on the durability of the grooved top layer. Two different Marshall asphalt mixtures with a different maximum granulate size (10 mm or 14 mm) are compared, both in the laboratory and in a full-scale trial. In the laboratory the resistance against rutting and raveling are investigated for both mixtures with and without adhesion promotor, which did not show a positive effect. In the full-scale trial the compactability and impact of both a longer curing period and a variation in the degree of compaction on the groove stability is investigated for both mixtures using a heavy truck. No visual differences could be found except in areas which were undercompacted and showed more damage to the grooves.

Rear-side picosecond laser ablation of indium tin oxide micro-grooves

NASA Astrophysics Data System (ADS)

Liu, Peng; Wang, Wenjun; Mei, Xuesong; Liu, Bin; Zhao, Wanqin

2015-06-01

A comparative study of the fabrication of micro-grooves in indium tin oxide films by picosecond laser ablation for application in thin film solar cells is presented, evaluating the variation of different process parameters. Compared with traditional front-side ablation, rear-side ablation results in thinner grooves with varying laser power at a certain scan speed. In particular, and in contrast to front-side ablation, the width of the micro-grooves remains unchanged when the scan speed was changed. Thus, the micro-groove quality can be optimized by adjusting the scan speed while the groove width would not be affected. Furthermore, high-quality micro-grooves with ripple free surfaces and steep sidewalls could only be achieved when applying rear-side ablation. Finally, the formation mechanism of micro-cracks on the groove rims during rear-side ablation is analyzed and the cracks can be almost entirely eliminated by an optimization of the scan speed.

Polymer Scaffolds with Preferential Parallel Grooves Enhance Nerve Regeneration

PubMed Central

Mobasseri, Atefeh; Faroni, Alessandro; Minogue, Ben M.; Downes, Sandra; Reid, Adam J.

2015-01-01

We have modified the surface topography of poly ɛ-caprolactone (PCL) and polylactic acid (PLA) blended films to improve cell proliferation and to guide the regeneration of peripheral nerves. Films with differing shaped grooves were made using patterned silicon templates, sloped walls (SL), V-shaped (V), and square-shaped (SQ), and compared with nongrooved surfaces with micropits. The solvent cast films were tested in vitro using adult adipose-derived stem cells differentiated to Schwann cell-like cells. Cell attachment, proliferation, and cell orientation were all improved on the grooved surfaces, with SL grooves giving the best results. We present in vivo data on Sprague-Dawley rat sciatic nerve injury with a 10-mm gap, evaluating nerve regeneration at 3 weeks across a polymer nerve conduit modified with intraluminal grooves (SL, V, and SQ) and differing wall thicknesses (70, 100, 120, and 210 μm). The SL-grooved nerve conduit showed a significant improvement over the other topographical-shaped grooves, while increasing the conduit wall thickness saw no positive effect on the biological response of the regenerating nerve. Furthermore, the preferred SL-grooved conduit (C) with 70 μm wall thickness was compared with the current clinical gold standard of autologous nerve graft (Ag) in the rat 10-mm sciatic nerve gap model. At 3 weeks postsurgery, all nerve gaps across both groups were bridged with regenerated nerve fibers. At 16 weeks, features of regenerated axons were comparable between the autograft (Ag) and conduit (C) groups. End organ assessments of muscle weight, electromyography, and skin reinnervation were also similar between the groups. The comparable experimental outcome between conduit and autograft, suggests that the PCL/PLA conduit with inner lumen microstructured grooves could be used as a potential alternative treatment for peripheral nerve repair. PMID:25435096

Interproximal grooving in the Atapuerca-SH hominid dentitions.

PubMed

Bermúdez de Castro, J M; Arsuaga, J L; Pérez, P J

1997-03-01

The dental sample recovered from the Sima de los Huesos (SH) Middle Pleistocene cave site of the Sierra de Atapuerca (Spain) includes 296 specimens. Interproximal wear grooves have been observed in 20 maxillary and mandibular posterior teeth belonging to at least five of the 32 individuals identified so far in the SH hypodigm. Interproximal grooving affected only the adults, and at an age between 25 and 40 years. The appearance, morphology, and location pattern of the SH wear grooves are similar to those reported in other fossil hominids and in more recent human populations. Two alternative proposals, the toothpicking and the fiber or sinew processing hypotheses, compete for explaining the formation of this anomalous wear. The characteristics observed in the wear grooves of the SH teeth are compatible only with the habitual probing of interdental spaces by means of hard and inflexible objects. Dietary grit may also have contributed to the abrasion of the root walls during the motion of the dental probes.

Effectiveness of transverse grooves in rigid pavement

NASA Astrophysics Data System (ADS)

Gurney, G. F.; Bryden, J. E.

1982-10-01

Transverse grooves were installed at 11 intersection approaches on worn rigid pavement to reduce a high rate of wet road accidents. In most cases, accident reductions were experienced only at intersections with multiple negative operational characteristics, including higher approach speeds, limited sight distances, and frequent vehicle stopping for turns or stop signs. Intersections with no more than one negative characteristic generally did not benefit from grooving.

Evaporator film coefficients of grooved heat pipes

NASA Technical Reports Server (NTRS)

Kamotani, Y.

1978-01-01

The heat transfer rate in the meniscus attachment region of a grooved heat pipe evaporator is studied theoretically. The analysis shows that the evaporation takes place mainly in the region where the liquid changes its shape sharply. However, comparisons with available heat transfer data indicate that the heat transfer rate in the meniscus varying region is substantially reduced probably due to groove wall surface roughness.

Simulation of multipactor on the rectangular grooved dielectric surface

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

Cai, Libing; Wang, Jianguo, E-mail: wanguiuc@mail.xjtu.edu.cn; Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024

2015-11-15

Multipactor discharge on the rectangular grooved dielectric surface is simulated self-consistently by using a two-and-a-half dimensional (2.5 D) electrostatic particle-in-cell (PIC) code. Compared with the electromagnetic PIC code, the former can give much more accurate solution for the space charge field caused by the multipactor electrons and the deposited surface charge. According to the rectangular groove width and height, the multipactor can be divided into four models, the spatial distributions of the multipactor electrons and the space charge fields are presented for these models. It shows that the rectangular groove in different models gives very different suppression effect on themore » multipactor, effective and efficient suppression on the multipactor can only be reached with a proper groove size.« less

Grooved Armor Plate

DTIC Science & Technology

1935-05-16

that many of the olateo tested do sux^ ass the reouired limita by a considerable margin. Therefore, the efficiency of these grooved plate...Plpte Thicknesn B>lll<tle .Llji^f - ./.. s... a’ ^ea:: of All RtSUltS !’ Teen of Rlgbeot lOf of All Reoultr. s/i«- 1830 an« 7/16" ?180

Topography and Albedo Image of Grooved Terrain on Vesta

NASA Image and Video Library

2011-11-29

These images from NASA Dawn spacecraft show part of the grooved terrain in asteroid Vesta Pinaria quadrangle, which is in the southern hemisphere. Large-scale grooves and depressions can be seen running diagonally across the image.

Presence of a groove in the lateral wall of the human orbit.

PubMed Central

Santo Neto, H; Penteado, C V; de Carvalho, V C

1984-01-01

The presence of a groove in the lateral wall of the human orbit (Royle, 1973) was found in 45 of 100 orbits examined (45%). In 15 skulls the groove was present bilaterally. The groove probably lodges an anastomosis between the middle meningeal and infraorbital blood vessels. No reference to this groove was found in general anatomical texts. Images Fig. 1 PMID:6746401

The SSME seal test program: Leakage tests for helically-grooved seals

NASA Technical Reports Server (NTRS)

Childs, D. W.

1983-01-01

Helically grooved annular seal configurations were tested in highly turbulent flow to determine if reduced leakage and enhanced stability would result from the pumping action of the seal. It was found that: (1) leakage of a helically grooved seals decreases with running speed; (2) leakage reduction due to increased running speed is greater at lower values of R sub a; (3) an asymptote for leakage reduction is indicated with increasing running speed; (4) leakage is reduced by reducing the ridge (minimum) and average clearances; (5) leakage increases with increasing pitch angles and with increasing groove depth. Plain seals with smooth rotors and stators will leak more than a helically grooved seal. It was also found that plain seals with a rough rotor and a rough stator leak less than a properly designed helically grooved seal. A properly designed helically grooved seal consumes at least twice as much power as a conventional annular seal.

Appraisal of transverse nasal groove: a study.

PubMed

Sathyanarayana, Belagola D; Basavaraj, Halevoor B; Nischal, Kuchangi C; Swaroop, Mukunda R; Umashankar, Puttagangu N; Agrawal, Dhruv P; Swamy, Suchetha S; Okram, Sarda

2012-01-01

Transverse nasal groove is a condition of cosmetic concern which awaits due recognition and has been widely described as a shallow groove that extends transversely over the dorsum of nose. However, we observed variations in the clinical presentations of this entity, hitherto undescribed in literature. We conducted a clinicoepidemiological study of transverse nasal lesions in patients attending our outpatient department. We conducted a prospective observational study. We screened all patients attending our out-patient department for presence of transverse nasal lesions, signs of any dermatosis and associated other skin conditions. One hundred patients were recruited in the study. Females (80%) predominated over males. Most patients were of 15-45 years age group (70%). Majority of the transverse nasal lesions were classical transverse nasal groove (39%) and others included transverse nasal line (28%), strip (28%), ridge (4%) and loop (1%). Seborrhoeic diathesis was the most common condition associated with transverse nasal lesion. Occurrence of transverse nasal line, strip, ridge and loop, in addition to classical transverse nasal groove implies that latter is actually a subset of transverse nasal lesions. Common association of this entity with seborrheic dermatitis, seborrhea and dandruff raises a possibility of whether transverse nasal lesion is a manifestation of seborrheic diathesis.

Design of well and groove microchannel bioreactors for cell culture.

PubMed

Korin, Natanel; Bransky, Avishay; Khoury, Maria; Dinnar, Uri; Levenberg, Shulamit

2009-03-01

Microfluidic bioreactors have been shown valuable for various cellular applications. The use of micro-wells/grooves bioreactors, in which micro-topographical features are used to protect sensitive cells from the detrimental effects of fluidic shear stress, is a promising approach to culture sensitive cells in these perfusion microsystems. However, such devices exhibit substantially different fluid dynamics and mass transport characteristics compared to conventional planar microchannel reactors. In order to properly design and optimize these systems, fluid and mass transport issues playing a key role in microscale bioreactors should be adequately addressed. The present work is a parametric study of micro-groove/micro-well microchannel bioreactors. Operation conditions and design parameters were theoretically examined via a numerical model. The complex flow pattern obtained at grooves of various depths was studied and the shear protection factor compared to planar microchannels was evaluated. 3D flow simulations were preformed in order to examine the shear protection factor in micro-wells, which were found to have similar attributes as the grooves. The oxygen mass transport problem, which is coupled to the fluid mechanics problem, was solved for various groove geometries and for several cell types, assuming a defined shear stress limitation. It is shown that by optimizing the groove depth, the groove bioreactor may be used to effectively maximize the number of cells cultured within it or to minimize the oxygen gradient existing in such devices. Moreover, for sensitive cells having a high oxygen demand (e.g., hepatocytes) or low endurance to shear (e.g., human embryonic stem cells), results show that the use of grooves is an enabling technology, since under the same physical conditions the cells cannot be cultured for long periods of time in a planar microchannel. In addition to the theoretical model findings, the culture of human foreskin fibroblasts in groove (30

Effect of type and location of oil groove on the performance of journal bearings

NASA Technical Reports Server (NTRS)

Vijayaraghavan, D.; Keith, T. G., Jr.

1992-01-01

A numerical study is performed of oil groove type (circumferential and axial), groove number (single and double) and groove location on journal bearing performance. The analysis involves the use of a cavitation algorithm. The interaction between cavitation phenomena and grooving is determined. Quantitative information is provided which will aid designers to better locate oil feed grooves.

Heat capacity of xenon adsorbed on nanobundle grooves

NASA Astrophysics Data System (ADS)

Chishko, K. A.; Sokolova, E. S.

2016-02-01

A model of a one-dimensional nonideal gas in an external transverse force field is used to interpret the experimentally observed thermodynamic properties of xenon deposited in grooves on the surface of carbon nanobundles. A nonideal gas model with pairwise interactions is not entirely adequate for describing dense adsorbates (at low temperatures), but makes it easy to account for the exchange of particles between the 1D adsorbate and the 3D atmosphere, which is an important factor at intermediate (on the order of 35 K for xenon) and, especially, high (˜100 K) temperatures. In this paper, we examine a 1D real gas taking only the one-dimensional Lennard-Jones interaction into account, but under exact equilibrium with respect to the number of particles between the 1D adsorbate and the 3D atmosphere of the measurement cell. The low-temperature branch of the specific heat is fitted independently by an elastic chain model so as to obtain the best agreement between theory and experiment over the widest possible region, beginning at zero temperature. The gas approximation sets in after temperatures for which the phonon specific heat of the chain essentially transforms to a one-dimensional equipartition law. Here the basic parameters of both models can be chosen so that the heat capacity C(T) of the chain transforms essentially continuously into the corresponding curve for the gas approximation. Thus, it can be expected that an adequate interpretation of the real temperature dependences of the specific heat of low-dimensionality atomic adsorbates can be obtained through a reasonable combination of the phonon and gas approximations. The main parameters of the gas approximation (such as the desorption energy) obtained by fitting the theory to experiments on the specific heat of xenon correlate well with published data.

[A case of groove pancreatitis associated with duodenal ulcer].

PubMed

Iemoto, Takao; Shiomi, Hideyuki; Masuda, Atsuhiro; Sanuki, Tsuyoshi; Kutsumi, Hiromu; Hayakumo, Takanobu; Shinzeki, Makoto; Matsumoto, Ippei; Ku, Yonson; Kanzawa, Maki; Hara, Shigeo; Azuma, Takeshi

2013-01-01

We describe a 69-year-old man with a history of multiple gastroduodenal ulcers, presenting with the onset of obstructive jaundice. Abdominal CT, MRI and EUS demonstrated a sheet-like mass in the pancreaticoduodenal groove. EUS-FNA did not reveal malignancy. Conservative treatment did not improve his clinical condition and repeated acute pancreatitis occurred during his treatment. Thus, pancreaticoduodenectomy was performed. Histopathological findings showed a duodenal ulcer penetrating the pancreas and infiltration of inflammatory cells and fibrosis in the pancreaticoduodenal groove. The spread of inflammation associated with the duodenal ulcer may have been one of the causes of groove pancreatitis.

Grooved impactor and inertial trap for sampling inhalable particulate matter

DOEpatents

Loo, Billy W.

1984-01-01

An inertial trap and grooved impactor for providing a sharp cutoff for particles over 15 microns from entering an inhalable particulate sampler. The impactor head has a tapered surface and is provided with V-shaped grooves. The tapered surface functions for reducing particle blow-off or reentrainment while the grooves prevent particle bounce. Water droplets and any resuspended material over the 15 micron size are collected by the inertial trap and deposited in a reservoir associated with the impactor.

Wet Weather Crater Repair Technologies for Grooved and Smooth Pavements

DTIC Science & Technology

2018-04-30

test area needed for this project, the PCC slab was grooved by using a walk-behind saw equipped with one diamond saw- cutting blade rather than a...tent. Figure 49 shows the rainwater running off the edge of the tent. Figure 49. Tent water runoff from simulated rain. Figure 50 shows the catch...covered with the tarp. These barriers still left the pavement grooving exposed, so water was able to run freely into the basin from the grooves. The

Osteochondritis Dissecans Involving the Trochlear Groove Treated With Retrograde Drilling

PubMed Central

Kaji, Yoshio; Nakamura, Osamu; Yamaguchi, Konosuke; Yamamoto, Tetsuji

2015-01-01

Abstract Osteochondritis dissecans (OCD) occurs frequently in the humeral capitellum of the upper extremity, whereas OCD involving the trochlear groove (trochlear groove OCD) is rarely reported. A standard treatment for trochlear groove OCD has therefore not been determined, although several methods have been tried. The case of a 14-year-old male gymnast with bilateral trochlear groove OCD is presented. Retrograde drilling from the lateral condyle of the humerus was applied for the OCD lesion of the left elbow, since it was larger in size than that in the right elbow and was symptomatic. Conversely, since the right lesion was small and asymptomatic, it was managed conservatively. After treatment, consolidation of the OCD lesions was observed in both elbows. However, the time to healing was shorter in the left elbow treated surgically than in the right elbow managed conservatively. In conclusion, retrograde drilling is a very simple and minimally invasive treatment. This case suggests that retrograde drilling for trochlear groove OCD may be a useful procedure that may accelerate the healing process for OCD lesions. PMID:26356703

Sutureless Technique to Fix the Great Saphenous Vein along the Atrioventricular Groove Using Fibrin Glue in Off-Pump Coronary Artery Bypass Grafting.

PubMed

Ohira, Suguru; Doi, Kiyoshi; Yaku, Hitoshi

2016-04-05

We describe a simple method to fix the great saphenous vein graft (SVG) to the right coronary artery along the atrioventricular groove using fibrin glue in off-pump coronary artery bypass grafting (OPCAB). After completion of the proximal anastomosis, the SVG was placed along the atrioventricular groove to the acute margin. Fibrin glue was sprayed using pressurized carbon dioxide gas. A distal anastomosis was subsequently performed after rotating the heart to expose the posterior descending artery. It is a straightforward and reproducible technique to determine the optimal length of the SVG and prevent kinking or stretching of the graft, especially in OPCAB.

Infiltration of Slag Film into the Grooves on a Continuous Casting Mold

NASA Astrophysics Data System (ADS)

Cho, Jung-Wook; Jeong, Hee-Tae

2013-02-01

An analytical model is developed to clarify the slag film infiltration into grooves on a copper mold during the continuous casting of steel slabs. A grooved-type casting mold was applied to investigate the infiltration of slag film into the grooves of a pitch of 0.8 mm, width of 0.7 mm, and depth of 0.6 mm at the vicinity of a meniscus. The plant trial tests were carried out at a casting speed of 5.5 m min-1. The slag film captured at a commercial thin slab casting plant showed that both the overall and the liquid film thickness were decreased exponentially as the distance from the meniscus increases. In contrast, the infiltration of slag film into the grooves had been increased with increasing distance from the meniscus. A theoretic model has been derived based on the measured profile of slag film thickness to calculate the infiltration of slag film into the grooves. It successfully reproduces the empirical observation that infiltration ratio increased sharply along casting direction, about 80 pct at 50 mm and 95 pct at 150 mm below the meniscus. In the model calculation, the infiltration of slag film increases with increasing groove width and/or surface tension of the slag. The effect of groove depth is negligible when the width to depth ratio of the groove is larger than unity. It is expected that the developed model for slag film infiltration in this study will be widely utilized to optimize the design of groove dimensions in continuous casting molds.

Syncopation, body-movement and pleasure in groove music.

PubMed

Witek, Maria A G; Clarke, Eric F; Wallentin, Mikkel; Kringelbach, Morten L; Vuust, Peter

2014-01-01

Moving to music is an essential human pleasure particularly related to musical groove. Structurally, music associated with groove is often characterised by rhythmic complexity in the form of syncopation, frequently observed in musical styles such as funk, hip-hop and electronic dance music. Structural complexity has been related to positive affect in music more broadly, but the function of syncopation in eliciting pleasure and body-movement in groove is unknown. Here we report results from a web-based survey which investigated the relationship between syncopation and ratings of wanting to move and experienced pleasure. Participants heard funk drum-breaks with varying degrees of syncopation and audio entropy, and rated the extent to which the drum-breaks made them want to move and how much pleasure they experienced. While entropy was found to be a poor predictor of wanting to move and pleasure, the results showed that medium degrees of syncopation elicited the most desire to move and the most pleasure, particularly for participants who enjoy dancing to music. Hence, there is an inverted U-shaped relationship between syncopation, body-movement and pleasure, and syncopation seems to be an important structural factor in embodied and affective responses to groove.

The origin of N III lambda 990 and C III lambda 977 emission in AGN narrow-line region gas

NASA Technical Reports Server (NTRS)

Ferguson, J. W.; Ferland, G. J.; Pradhan, A. K.

1995-01-01

We discuss implications of Hopkins Ultraviolet Telescope (HUT) detections of C III lambda 977 and N III lambda 990 emission from the narrow-line region of the Seyfert 2 galaxy NGC 1068. In their discovery paper Kriss et al. showed that the unexpectedly great strength of these lines implies that the emitting gas must be shock-heated if the lines are collisionally excited. Here we investigate other processes which excite these lines in photoionization equilibrium. Recombination, mainly dielectronic, and continuum fluorescence are strong contributors to the line. The resulting intensities are sensitive to the velocity field of the emitting gas and require that the turbulence be of the same order of magnitude as the observed line width. We propose optical observations that will decide whether the gas is collisionally or radiatively heated.

Mechanical grooving effect on the gettering efficiency of crystalline silicon based solar cells

NASA Astrophysics Data System (ADS)

Zarroug, Ahmed; Hamed, Zied Ben; Derbali, Lotfi; Ezzaouia, Hatem

2017-04-01

This paper examines a gettering process of Czochralski silicon (CZ) via mechanical texture, followed by two step heat treatment in the presence of porous silicon layer (PSL) under oxygen flow gas. It is shown that a process with PS has a positive trend of improvement in the electronic quality, and found to be more efficient when used in combination with mechanical grooving. We obtained a significant increase of the effective minority carrier lifetime and majority charge carriers mobility. Thus, there is an apparent decrease in the resistivity. These parameters were estimated through a The Quasi-Steady-State Photo-Conductance technique (QSSPC), the van Der Pauw method and Hall Effect. Particularly, we have made obvious that the large enhancement of the electronic quality of the wafers can be related to the presence of grooves, the influence during which the gettering process is of importance to overcome the unexpected saturation phenomena. The current voltage I-V characteristics of all samples had been measured under illumination. They were shown to enhance the photovoltaic properties of solar cells.

Resistance to minor groove binders.

PubMed

Colmegna, Benedetta; Uboldi, Sarah; Erba, Eugenio; D'Incalci, Maurizio

2014-03-01

In this paper multiple resistance mechanisms to minor groove binders (MGBs) are overviewed. MGBs with antitumor properties are natural products or their derivatives and, as expected, they are all substrates of P-glycoprotein (P-gp). However, a moderate expression of P-gp does not appear to reduce the sensitivity to trabectedin, the only MGB so far approved for clinical use. Resistance to this drug is often related to transcriptional mechanisms and to DNA repair pathways, particularly defects in transcription-coupled nucleotide excision repair (TC-NER). Therefore tumors resistant to trabectedin may become hypersensitive to UV rays and other DNA damaging agents acting in the major groove, such as Platinum (Pt) complexes. If this is confirmed in clinic, that will provide the rationale to combine trabectedin sequentially with Pt derivates.

Champagne Groove Lipectomy: A Safe Technique to Contour the Upper Abdomen in Abdominoplasty.

PubMed

Brooks, Ron; Nguyen, Jonathan; Chowdhry, Saeed; Tutela, John Paul; Kelishadi, Sean; Yonick, David; Choo, Joshua; Wilhelmi, Bradon J

2017-01-01

Objective: Combined liposuction and abdominoplasty, or lipoabdominoplasty, is particularly helpful in sculpting a more aesthetically pleasing abdominal contour, particularly in the supraumbilical midline groove. This groove, coined the "champagne groove" by one of our patients, is a frequently sought-after attribute by patients. However, liposuction adds time and cost to an already costly abdominoplasty. We sought to create this groove without the addition of liposuction, utilizing what we call a champagne groove lipectomy. This study reports on our champagne groove lipectomy technique and compares our complication rates with those reported in the literature for standard abdominoplasty techniques. Methods: This is a retrospective review of a single surgeon's experience at our institution over a 6-year period (2007-2012). A total of 74 patients undergoing consecutive abdominoplasty were studied, all female nonsmokers. Two groups were recognized: 64 of 74 patients underwent abdominoplasty, partial belt lipectomy, and champagne groove lipectomy, while 10 of 74 patients underwent fleur-de-lis abdominoplasty without champagne groove lipectomy. Results: Overall, 10 of 74 patients (13.5%) suffered some type of complication, which compares favorably with reported rates in the literature. The majority of complications were related to delayed wound healing or superficial wound dehiscence. Among those patients who underwent champagne groove lipectomy, complications occurred in 6 of 64 patients (9.3%), versus 4 of 10 (40%) patients undergoing fleur-de-lis abdominoplasty. Conclusions: Champagne groove lipectomy is a cost-effective alternative to lipoabdominoplasty for achieving an aesthetically pleasing upper midline abdominal contour, with complication rates comparing favorably with those reported in the literature.

Current trends in the management of pediatric patients with perineal groove.

PubMed

Esposito, Ciro; Giurin, Ida; Savanelli, Antonio; Alicchio, Francesca; Settimi, Alessandro

2011-10-01

Perineal groove is an uncommon congenital anomaly of the perineum, affecting young girls. We report our experience in the treatment of this pathology. Retrospective review of patients operated in our institution for a perineal groove between 1999 and 2007. Multidisciplinary clinic for young girls with perineal groove at the Department of Pediatrics, "Federico II" University, Naples, Italy. Six young girls (aged between 2 and 7 years) with perineal groove. In the first three patients, who were operated on before 2004, the procedure consisted in resecting the groove and closing the perineal defect using interrupted sutures; in the last three, the skin was closed with similar approach and then covered with a chemical glue to impermeabilize and protect the suture. At a long-term follow-up, two of the three patients operated before 2004 experienced dehiscence of the perineal skin due to urine and feces contamination; in the last three patients in whom the sutures were covered with glue there was no skin dehiscence, and the postoperative course was uneventful. A perineal groove is a rare anomaly in young girls. Treatment consists in the surgical excision of the groove, generally after two years of age. On the basis of our experience it is preferable to cover the suture with a chemical glue to impermeabilize the suture line and protect the skin from infections. Copyright © 2011 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Documentation of roller-bearing effect on butterfly inspired grooves

NASA Astrophysics Data System (ADS)

Gautam, Sashank; Lang, Amy

2017-11-01

Butterfly wings are covered with scales in a roof shingle pattern which align together to form grooves. The increase or decrease of laminar friction drag depends on the flow orientation to the scales. Flow in the longitudinal direction to the grooves encounters increased surface area which increases the friction drag. However, in the transverse direction, for low Re laminar flow, a single vortex is formed inside each groove and is predicted to remain stable due to the very low Re of the flow in each cavity. These embedded vortices act as roller bearings to the flow above, such that the fluid from the outer boundary layer does not mix with fluid inside the cavities. This leads to a reduction of skin friction drag when compared to a smooth surface. When the cavity flow Re is increased beyond a critical point, the vortex becomes unstable and the low-momentum fluid in the grooves mixes with the outer boundary layer flow, increasing the drag. The objective of this experiment is to determine the critical Re where the embedded vortex transitions from a stable to an unstable state using DPIV. Subsequently, for steady vortex conditions, a comparison of skin friction drag between the grooved and flat plate can show that the butterfly scaled surface can result in sub-laminar friction drag. The National Science Foundation (Grant No. 1335848).

Formation Mechanisms for Spur and Groove Features on Fringing Reefs

NASA Astrophysics Data System (ADS)

Bramante, J. F.; Ashton, A. D.; Perron, J. T.

2016-12-01

Spur and groove systems (SAGs) are ubiquitous morphological features found on fore-reef slopes globally. SAGs consist of parallel, roughly shore-normal ridges of actively growing coral and coralline algae (spurs) separated by offshore-sloping depressions typically carpeted by a veneer of sediment (grooves). Although anecdotal observations and recent statistical analyses have reported correlations between wave exposure and the distribution of SAGs on fore-reef slopes, the physical mechanisms driving SAG formation remain poorly understood. For example, there remains significant debate regarding the importance of coral growth versus bed erosion for SAG formation. Here we investigate a hypothesis that SAG formation is controlled by feedbacks between sediment production and diffusion and coral growth. Using linear stability analysis, we find that sediment production, coral growth, and the feedbacks between them are unable to produce stable periodic structures without a sediment sink. However, if incipient grooves act as conduits for sediment transport offshore, a positive feedback can develop as the groove bed erodes through wave-driven abrasion during offshore transport. Eventually a negative feedback slows groove deepening when the groove bed is armored by sediment, and the groove bed relaxes to a sediment-veneered equilibrium profile analogous to sediment-rich shorefaces. To test this hypothesis, we apply a numerical model that incorporates coral growth and sediment production, sediment diffusion, non-linear wave-driven abrasion, and sediment advection offshore. This model produces the periodic, linear features characteristic of SAG morphology. The relative magnitude of growth, production, diffusion, abrasion, and advection rates affect periodic spacing or wavelength of the modeled SAGs. Finally, we evaluate the ability of the model to replicate geographical variability in SAG characteristics using previously published datasets and reanalysis wave data.

Combined endodontic-periodontic treatment of a palatal groove: a case report.

PubMed

Schwartz, Scott A; Koch, Michael A; Deas, David E; Powell, Charles A

2006-06-01

The palatal groove is a developmental anomaly that predisposes the tooth involved to a severe periodontal defect. When further complicated by pulp necrosis, these grooves often present a diagnostic and treatment planning challenge that requires an interdisciplinary treatment approach. This case report describes the successful collaborative management of a maxillary lateral incisor with an extensive palatal groove using a combination of nonsurgical endodontic therapy, odontoplasty, and periodontal regenerative techniques.

Syncopation, Body-Movement and Pleasure in Groove Music

PubMed Central

Witek, Maria A. G.; Clarke, Eric F.; Wallentin, Mikkel; Kringelbach, Morten L.; Vuust, Peter

2014-01-01

Moving to music is an essential human pleasure particularly related to musical groove. Structurally, music associated with groove is often characterised by rhythmic complexity in the form of syncopation, frequently observed in musical styles such as funk, hip-hop and electronic dance music. Structural complexity has been related to positive affect in music more broadly, but the function of syncopation in eliciting pleasure and body-movement in groove is unknown. Here we report results from a web-based survey which investigated the relationship between syncopation and ratings of wanting to move and experienced pleasure. Participants heard funk drum-breaks with varying degrees of syncopation and audio entropy, and rated the extent to which the drum-breaks made them want to move and how much pleasure they experienced. While entropy was found to be a poor predictor of wanting to move and pleasure, the results showed that medium degrees of syncopation elicited the most desire to move and the most pleasure, particularly for participants who enjoy dancing to music. Hence, there is an inverted U-shaped relationship between syncopation, body-movement and pleasure, and syncopation seems to be an important structural factor in embodied and affective responses to groove. PMID:24740381

Numerical investigation of a centrifugal compressor with circumferential grooves in vane diffuser

NASA Astrophysics Data System (ADS)

Chen, X. F.; Qin, G. L.; Ai, Z. J.

2015-08-01

Enhancing stall and surge margin has a great importance for the development of turbo compressors. The application of casing treatment is an effective measure to expand the stall margin and stable operation range. Numerical investigations were conducted to predict the performance of a low flow rate centrifugal compressor with circumferential groove casing treatment in vane diffuser. Numerical cases with different radial location, radial width and axial depth of a circumferential single groove and different numbers of circumferential grooves were carried out to compare the results. The CFD analyses results show that the centrifugal compressor with circumferential grooves in diffuser can extend stable range by about 9% while the efficiency over the whole operating range decreases by 0.2 to 1.7%. The evaluation based on stall margin improvement showed the optimal position for the groove to be located was indicated to exist near the leading edge of the diffuser, and a combination of position, width, depth and numbers of circumferential grooves that will maximize both surge margin range and efficiency.

Grooved Terrain on Ganymede: First Results from Galileo High-Resolution Imaging

USGS Publications Warehouse

Pappalardo, R.T.; Head, J.W.; Collins, G.C.; Kirk, R.L.; Neukum, G.; Oberst, J.; Giese, B.; Greeley, R.; Chapman, C.R.; Helfenstein, P.; Moore, Johnnie N.; McEwen, A.; Tufts, B.R.; Senske, D.A.; Herbert, Breneman H.; Klaasen, K.

1998-01-01

High-resolution Galileo imaging has provided important insight into the origin and evolution of grooved terrain on Ganymede. The Uruk Sulcus target site was the first imaged at high resolution, and considerations of resolution, viewing geometry, low image compression, and complementary stereo imaging make this region extremely informative. Contrast variations in these low-incidence angle images are extreme and give the visual impression of topographic shading. However, photometric analysis shows that the scene must owe its character to albedo variations. A close correlation of albedo variations to topography is demonstrated by limited stereo coverage, allowing extrapolation of the observed brightness and topographic relationships to the rest of the imaged area. Distinct geological units are apparent across the region, and ridges and grooves are ubiquitous within these units. The stratigraphically lowest and most heavily cratered units ("lineated grooved terrain") generally show morphologies indicative of horst-and-graben-style normal faulting. The stratigraphically highest groove lanes ("parallel ridged terrain") exhibit ridges of roughly triangular cross section, suggesting that tilt-block-style normal faulting has shaped them. These extensional-tectonic models are supported by crosscutting relationships at the margins of groove lanes. Thus, a change in tectonic style with time is suggested in the Uruk Sulcus region, varying from horst and graben faulting for the oldest grooved terrain units to tilt block normal faulting for the latest units. The morphologies and geometries of some stratigraphically high units indicate that a strike-slip component of deformation has played an important role in shaping this region of grooved terrain. The most recent tectonic episode is interpreted as right-lateral transtension, with its tectonic pattern of two contemporaneous structural orientations superimposed on older units of grooved terrain. There is little direct evidence for

Champagne Groove Lipectomy: A Safe Technique to Contour the Upper Abdomen in Abdominoplasty

PubMed Central

Brooks, Ron; Chowdhry, Saeed; Tutela, John Paul; Kelishadi, Sean; Yonick, David; Choo, Joshua; Wilhelmi, Bradon J.

2017-01-01

Objective: Combined liposuction and abdominoplasty, or lipoabdominoplasty, is particularly helpful in sculpting a more aesthetically pleasing abdominal contour, particularly in the supraumbilical midline groove. This groove, coined the “champagne groove” by one of our patients, is a frequently sought-after attribute by patients. However, liposuction adds time and cost to an already costly abdominoplasty. We sought to create this groove without the addition of liposuction, utilizing what we call a champagne groove lipectomy. This study reports on our champagne groove lipectomy technique and compares our complication rates with those reported in the literature for standard abdominoplasty techniques. Methods: This is a retrospective review of a single surgeon's experience at our institution over a 6-year period (2007-2012). A total of 74 patients undergoing consecutive abdominoplasty were studied, all female nonsmokers. Two groups were recognized: 64 of 74 patients underwent abdominoplasty, partial belt lipectomy, and champagne groove lipectomy, while 10 of 74 patients underwent fleur-de-lis abdominoplasty without champagne groove lipectomy. Results: Overall, 10 of 74 patients (13.5%) suffered some type of complication, which compares favorably with reported rates in the literature. The majority of complications were related to delayed wound healing or superficial wound dehiscence. Among those patients who underwent champagne groove lipectomy, complications occurred in 6 of 64 patients (9.3%), versus 4 of 10 (40%) patients undergoing fleur-de-lis abdominoplasty. Conclusions: Champagne groove lipectomy is a cost-effective alternative to lipoabdominoplasty for achieving an aesthetically pleasing upper midline abdominal contour, with complication rates comparing favorably with those reported in the literature. PMID:28293334

Study of Mastoid Canals and Grooves in North Karnataka Human Skulls

PubMed Central

Hadimani, Gavishiddappa Andanappa; Bagoji, Ishwar Basavantappa

2013-01-01

Introduction: This study was undertaken to observe the frequency of mastoid canals and grooves in north Karnataka dry human skulls. 100 dry human skulls of unknown age and sex from the department of Anatomy were selected and observed for the present study. Material and Methods: The mastoid regions of dry skulls were observed for the presence of mastoid canals and grooves, if any. A metallic wire was passed through the canal for its confirmation and then the length was measured. Results: The Mastoid canals were present in 53% of the total 100 skulls observed either bilaterally or unilaterally. Mastoid grooves were present in 18% of the total skulls (100) observed. Double mastoid canal was found in 01% of total skull studied and both Mastoid canals & Mastoid grooves together were present in 02% of the total skulls (100) observed. Conclusion: The knowledge of mastoid canals and grooves is very important for otolaryngologists and neurosurgeons. Because they contain an arterial branch of occipital artery with its accompanying vein which is liable to injury resulting into severe bleeding. PMID:24086832

Study of mastoid canals and grooves in north karnataka human skulls.

PubMed

Hadimani, Gavishiddappa Andanappa; Bagoji, Ishwar Basavantappa

2013-08-01

This study was undertaken to observe the frequency of mastoid canals and grooves in north Karnataka dry human skulls. 100 dry human skulls of unknown age and sex from the department of Anatomy were selected and observed for the present study. The mastoid regions of dry skulls were observed for the presence of mastoid canals and grooves, if any. A metallic wire was passed through the canal for its confirmation and then the length was measured. The Mastoid canals were present in 53% of the total 100 skulls observed either bilaterally or unilaterally. Mastoid grooves were present in 18% of the total skulls (100) observed. Double mastoid canal was found in 01% of total skull studied and both Mastoid canals & Mastoid grooves together were present in 02% of the total skulls (100) observed. The knowledge of mastoid canals and grooves is very important for otolaryngologists and neurosurgeons. Because they contain an arterial branch of occipital artery with its accompanying vein which is liable to injury resulting into severe bleeding.

Miranda Fractures, Grooves and Craters

NASA Image and Video Library

1996-01-29

This image of the Uranian moon, Miranda, was taken Jan 24, 1986 by NASA's Voyager 2. This image reveals a bewildering variety of fractures, grooves and craters, as well as features of different albedos reflectancea. http://photojournal.jpl.nasa.gov/catalog/PIA00140

Fluidic Grooves on Doped-Ice Surface as Size-Tunable Channels

PubMed Central

Inagawa, Arinori; Harada, Makoto; Okada, Tetsuo

2015-01-01

We propose a new principle for fabrication of size-tunable fluidic nano- and microchannels with a ubiquitous green material, water. Grooves filled with a solution are spontaneously formed on the surface of ice when an appropriate dopant is incorporated. Sucrose doping allows the development of grooves with lengths of 300 μm along the boundaries of ice crystal grains. This paper focuses on controlling the size of the liquid-filled groove and reveals its applicability to size-selective differentiation of nano- and micromaterials. The width of this groove can be varied in a range of 200 nm to 4 μm by adjusting the working temperature of the frozen platform. The channel dimension is reproducible as long as the same frozen condition is employed. We demonstrate the size-selective entrapment of particles as well as the state evaluation of DNA by controlling the physical interference of the ice wall with the electrophoretic migration of particles. PMID:26601703

Fluidic Grooves on Doped-Ice Surface as Size-Tunable Channels

NASA Astrophysics Data System (ADS)

Inagawa, Arinori; Harada, Makoto; Okada, Tetsuo

2015-11-01

We propose a new principle for fabrication of size-tunable fluidic nano- and microchannels with a ubiquitous green material, water. Grooves filled with a solution are spontaneously formed on the surface of ice when an appropriate dopant is incorporated. Sucrose doping allows the development of grooves with lengths of 300 μm along the boundaries of ice crystal grains. This paper focuses on controlling the size of the liquid-filled groove and reveals its applicability to size-selective differentiation of nano- and micromaterials. The width of this groove can be varied in a range of 200 nm to 4 μm by adjusting the working temperature of the frozen platform. The channel dimension is reproducible as long as the same frozen condition is employed. We demonstrate the size-selective entrapment of particles as well as the state evaluation of DNA by controlling the physical interference of the ice wall with the electrophoretic migration of particles.

Industrial Computer Codes

NASA Technical Reports Server (NTRS)

Shapiro, Wilbur

1996-01-01

This is an overview of new and updated industrial codes for seal design and testing. GCYLT (gas cylindrical seals -- turbulent), SPIRALI (spiral-groove seals -- incompressible), KTK (knife to knife) Labyrinth Seal Code, and DYSEAL (dynamic seal analysis) are covered. CGYLT uses G-factors for Poiseuille and Couette turbulence coefficients. SPIRALI is updated to include turbulence and inertia, but maintains the narrow groove theory. KTK labyrinth seal code handles straight or stepped seals. And DYSEAL provides dynamics for the seal geometry.

Fabrication process for polymer PLC platforms with V-grooves for passive alignment

NASA Astrophysics Data System (ADS)

Park, Suntak; Lee, Jong-Moo; Ahn, Joon Tae; Baek, Yong-Soon

2005-12-01

A method for polymer planar lightwave circuit (PLC) devices fabricated on a substrate with V-grooves is developed for passive alignment of an optical fiber to a polymer waveguide. In order to minimize thickness nonuniformity of polymer layers caused by the V-grooves, dry film resist (DFR) is used. The V-grooves are covered with the DFR before the polymer layers are spin-coated on the substrate. The DFR prevents the polymer from being filled in the V-grooves as well as from being spin-coated nonuniformly on the substrate. This process provides a simple and cost-effective fabrication method of polymer PLCs or platforms for passive alignment.

Laser etching of groove structures with micro-optical fiber-enhanced irradiation

PubMed Central

2012-01-01

A microfiber is used as a laser-focusing unit to fabricate a groove structure on TiAlSiN surfaces. After one laser pulse etching, a groove with the minimum width of 265 nm is manufactured at the area. This technique of microfabricating the groove in microscale is studied. Based on the near-field intensity enhancement at the contact area between the fiber and the surface during the laser irradiation, simulation results are also presented, which agree well with the experimental results. PMID:22713521

The origin of the grooves on Phobos

NASA Technical Reports Server (NTRS)

Thomas, P. C.; Veverka, J.; Duxbury, T.

1977-01-01

Various theories for the long, linear depressions on the surface of Phobos are reviewed. Imagery from Viking Orbiters is used to map the surface distribution of the grooves, study their morphology, and date them by means of the density of superimposed impact craters. Data is presented which tends to support the hypothesis that the deep-seated fracturing was caused by a large, nearly catastrophic cratering event. It is suggested that the grooves were produced during the creation of the Stickney crater, rather than as the result of tidal stresses induced by Mars or by drag forces during the hypothetical capture of the satellite by Mars.

Narrow Escape of Interacting Diffusing Particles

NASA Astrophysics Data System (ADS)

Agranov, Tal; Meerson, Baruch

2018-03-01

The narrow escape problem deals with the calculation of the mean escape time (MET) of a Brownian particle from a bounded domain through a small hole on the domain's boundary. Here we develop a formalism which allows us to evaluate the nonescape probability of a gas of diffusing particles that may interact with each other. In some cases the nonescape probability allows us to evaluate the MET of the first particle. The formalism is based on the fluctuating hydrodynamics and the recently developed macroscopic fluctuation theory. We also uncover an unexpected connection between the narrow escape of interacting particles and thermal runaway in chemical reactors.

Individual Differences in Beat Perception Affect Gait Responses to Low- and High-Groove Music

PubMed Central

Leow, Li-Ann; Parrott, Taylor; Grahn, Jessica A.

2014-01-01

Slowed gait in patients with Parkinson’s disease (PD) can be improved when patients synchronize footsteps to isochronous metronome cues, but limited retention of such improvements suggest that permanent cueing regimes are needed for long-term improvements. If so, music might make permanent cueing regimes more pleasant, improving adherence; however, music cueing requires patients to synchronize movements to the “beat,” which might be difficult for patients with PD who tend to show weak beat perception. One solution may be to use high-groove music, which has high beat salience that may facilitate synchronization, and affective properties, which may improve motivation to move. As a first step to understanding how beat perception affects gait in complex neurological disorders, we examined how beat perception ability affected gait in neurotypical adults. Synchronization performance and gait parameters were assessed as healthy young adults with strong or weak beat perception synchronized to low-groove music, high-groove music, and metronome cues. High-groove music was predicted to elicit better synchronization than low-groove music, due to its higher beat salience. Two musical tempi, or rates, were used: (1) preferred tempo: beat rate matched to preferred step rate and (2) faster tempo: beat rate adjusted to 22.5% faster than preferred step rate. For both strong and weak beat-perceivers, synchronization performance was best with metronome cues, followed by high-groove music, and worst with low-groove music. In addition, high-groove music elicited longer and faster steps than low-groove music, both at preferred tempo and at faster tempo. Low-groove music was particularly detrimental to gait in weak beat-perceivers, who showed slower and shorter steps compared to uncued walking. The findings show that individual differences in beat perception affect gait when synchronizing footsteps to music, and have implications for using music in gait rehabilitation. PMID:25374521

Aerodynamic Inner Workings of Circumferential Grooves in a Transonic Axial Compressor

NASA Technical Reports Server (NTRS)

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

2007-01-01

The current paper reports on investigations of the fundamental flow mechanisms of circumferential grooves applied to a transonic axial compressor. Experimental results show that the compressor stall margin is significantly improved with the current set of circumferential grooves. The primary focus of the current investigation is to advance understanding of basic flow mechanics behind the observed improvement of stall margin. Experimental data and numerical simulations of a circumferential groove were analyzed in detail to unlock the inner workings of the circumferential grooves in the current transonic compressor rotor. A short length scale stall inception occurs when a large flow blockage is built on the pressure side of the blade near the leading edge and incoming flow spills over to the adjacent blade passage due to this blockage. The current study reveals that a large portion of this blockage is created by the tip clearance flow originating from 20% to 50% chord of the blade from the leading edge. Tip clearance flows originating from the leading edge up to 20% chord form a tip clearance core vortex and this tip clearance core vortex travels radially inward. The tip clearance flows originating from 20% to 50% chord travels over this tip clearance core vortex and reaches to the pressure side. This part of tip clearance flow is of low momentum as it is coming from the casing boundary layer and the blade suction surface boundary layer. The circumferential grooves disturb this part of the tip clearance flow close to the casing. Consequently the buildup of the induced vortex and the blockage near the pressure side of the passage is reduced. This is the main mechanism of the circumferential grooves that delays the formation of blockage near the pressure side of the passage and delays the onset of short length scale stall inception. The primary effect of the circumferential grooves is preventing local blockage near the pressure side of the blade leading edge that

Correcting groove error in gratings ruled on a 500-mm ruling engine using interferometric control.

PubMed

Mi, Xiaotao; Yu, Haili; Yu, Hongzhu; Zhang, Shanwen; Li, Xiaotian; Yao, Xuefeng; Qi, Xiangdong; Bayinhedhig; Wan, Qiuhua

2017-07-20

Groove error is one of the most important factors affecting grating quality and spectral performance. To reduce groove error, we propose a new ruling-tool carriage system based on aerostatic guideways. We design a new blank carriage system with double piezoelectric actuators. We also propose a completely closed-loop servo-control system with a new optical measurement system that can control the position of the diamond relative to the blank. To evaluate our proposed methods, we produced several gratings, including an echelle grating with 79  grooves/mm, a grating with 768  grooves/mm, and a high-density grating with 6000  grooves/mm. The results show that our methods effectively reduce groove error in ruled gratings.

Laser melting of groove defect repair on high thermal conductivity steel (HTCS-150)

NASA Astrophysics Data System (ADS)

Norhafzan, B.; Aqida, S. N.; Fazliana, F.; Reza, M. S.; Ismail, I.; Khairil, C. M.

2018-02-01

This paper presents laser melting repair of groove defect on HTCS-150 surface using Nd:YAG laser system. Laser melting process was conducted using JK300HPS Nd:YAG twin lamp laser source with 1064 nm wavelength and pulsed mode. The parameters are pulse repetition frequency (PRF) that is set from 70 to 100 Hz, average power ( P A) of 50-70 W, and laser spot size of 0.7 mm. HTCS-150 samples were prepared with groove dimension of 0.3 mm width and depths of 0.5 mm using EDM wire cut. Groove defect repaired using laser melting process on groove surface area with various parameters' process. The melted surface within the groove was characterized for subsurface hardness profile, roughness, phase identification, chemical composition, and metallographic study. The roughness analysis indicates high PRF at large spot size caused high surface roughness and low surface hardness. Grain refinement of repaired layer was analyzed within the groove as a result of rapid heating and cooling. The hardness properties of modified HTCS inside the groove and the bulk surface increased two times from as received HTCS due to grain refinement which is in agreement with Hall-Petch equation. These findings are significant to parameter design of die repair for optimum surface integrity and potential for repairing crack depth and width of less than 0.5 and 0.3 mm, respectively.

Forming Ganymede's grooves at smaller strain: Toward a self-consistent local and global strain history for Ganymede

NASA Astrophysics Data System (ADS)

Bland, Michael T.; McKinnon, William B.

2015-01-01

The ubiquity of tectonic features formed in extension, and the apparent absence of ones formed in contraction, has led to the hypothesis that Ganymede has undergone global expansion in its past. Determining the magnitude of such expansion is challenging however, and extrapolation of locally or regionally inferred strains to global scales often results in strain estimates that exceed those based on global constraints. Here we use numerical simulations of groove terrain formation to develop a strain history for Ganymede that is generally consistent at local, regional, and global scales. These simulations reproduce groove-like amplitudes, wavelengths, and average slopes at modest regional extensions (10-15%). The modest strains are more consistent with global constraints on Ganymede's expansion. Yet locally, we also find that surface strains can be much larger (30-60%) in the same simulations, consistent with observations of highly-extended impact craters. Thus our simulations satisfy both the smallest-scale and largest-scale inferences of strain on Ganymede. The growth rate of the topography is consistent with (or exceeds) predictions of analytical models, and results from the use of a non-associated plastic rheology that naturally permits localization of brittle failure (plastic strain) into linear fault-like shear zones. These fault-like zones are organized into periodically-spaced graben-like structures with stepped, steeply-dipping faults. As in previous work, groove amplitudes and wavelengths depend on both the imposed heat flux and surface temperature, but because our brittle strength increases with depth, we find (for the parameters explored) that the growth rate of topography is initially faster for lower heat flows. We observe a transition to narrow rifting for higher heat flows and larger strains, which is a potential pathway for breakaway margin or band formation.

From the Bandstand to the Classroom: Thinking and Playing Grooves

ERIC Educational Resources Information Center

Baxter, Marsha; Santantasio, Christopher

2012-01-01

In this article, narratives of a salsa concert and a lesson with a Native American flute performer provide openings for exploring grooves and their application in the music classroom. The term "groove" is examined, along with some non-Western ideas about time as represented in the music of the West African Kpelle people. A sixth-grade…

[Developmental radicular groove as a cause of endodontic failure].

PubMed

Fabra Campos, H; Millet Part, J

1989-01-01

A clinical case of apical injury on an upper lateral incisor with endodontical and surgical failures in its treatment is presented. Extraction of the incisor and its study at the stereoscopic microscope showed the existence of a developmental groove running from the cingulum to the end of the root, establishing a communication between the crevice and the apical part of the tooth. Bacterial infection through the groove could provide an explanation for treatment failure.

Grooving of concrete pavements : final report.

DOT National Transportation Integrated Search

1973-08-01

This project was initiated by the Louisiana Department of Highways in cooperation with the Federal Highway Administration to determine whether transverse diamond cut grooves of a certain style (Christensen Style 7) placed in hardened concrete in seve...

Laser beam joining of optical fibers in silicon V-grooves

NASA Astrophysics Data System (ADS)

Kaufmann, Stefan; Otto, Andreas; Luz, Gerhard

2000-06-01

The increasing use of optical data transmission systems and the development of new optical components require adjustment-insensitive and reliable joining and assembling techniques. The state of the art includes the utilization of silicon submounts with anisotropically etched V-grooves. Several glass fibers are fixed in these V-grooves with adhesive. Adhesive bonds tend towards degradation under the influence of temperature and moisture. For this reason, the alternative joining processes laser beam welding and laser beam soldering are relevant. The goal is a reliable joining of optical fibers in V-grooves without damage to the fibers or the silicon submount. Because of the anomaly of silicon during phase transformation, a positive joining can be realized by laser beam welding. A melt pool is created through the energy of a Nd:YAG-laser pulse. During solidification, the volume of silicon increases and a bump is formed in the center. Experiments have shown that this phenomenon can be used for joining optical fibers in silicon-V-grooves. With suitable parameters the silicon flows half around the fiber during solidification. For each fiber, several welding points are necessary. Another promising joining method is laser bema soldering. In this case, a second silicon sheet with a solder deposit is placed on the fibers which lie in the V-grooves of the metallized silicon submount. The laser heats the upper silicon until the solder metals by heat conduction.

The Narrow-Line Region of Narrow-Line Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Rodríguez-Ardila, A.; Binette, Luc; Pastoriza, Miriani G.; Donzelli, Carlos J.

2000-08-01

This work studies the optical emission-line properties and physical conditions of the narrow-line region (NLR) of seven narrow-line Seyfert 1 galaxies (NLS1's) for which high signal-to-noise ratio spectroscopic observations were available. The resolution is 340 km s-1 (at Hα) over the wavelength interval 3700-9500 Å, enabling us to separate the broad and narrow components of the permitted emission lines. Our results show that the flux carried out by the narrow component of Hβ is, on average, 50% of the total line flux. As a result, the [O III] λ5007/Hβ ratio emitted in the NLR varies from 1 to 5, instead of the universally adopted value of 10. This has strong implications for the required spectral energy distribution that ionizes the NLR gas. Photoionization models that consider a NLR composed of a combination of matter-bounded and ionization-bounded clouds are successful at explaining the low [O III] λ5007/Hβ ratio and the weakness of low-ionization lines of NLS1's. Variation of the relative proportion of these two type of clouds nicely reproduces the dispersion of narrow-line ratios found among the NLS1 sample. Assuming similar physical model parameters of both NLS1's and the normal Seyfert 1 galaxy NGC 5548, we show that the observed differences of emission-line ratios between these two groups of galaxies can be explained, to a first approximation, in terms of the shape of the input ionizing continuum. Narrow emission-line ratios of NLS1's are better reproduced by a steep power-law continuum in the EUV-soft X-ray region, with spectral index α~-2. Flatter spectral indices (α~-1.5) match the observed line ratios of NGC 5548 but are unable to provide a good match to the NLS1 ratios. This result is consistent with ROSAT observations of NLS1's, which show that these objects are characterized by steeper power-law indices than those of Seyfert 1 galaxies with strong broad optical lines. Based on observations made at CASLEO. Complejo Astronómico El Leoncito

Hot gas path component having cast-in features for near wall cooling

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

Miranda, Carlos Miguel; Kottilingam, Srikanth Chandrudu; Lacy, Benjamin Paul

A hot gas path component includes a substrate having an outer surface and an inner surface. The inner surface of the substrate defines at least one interior space. At least a portion of the outer surface of the substrate includes a recess formed therein. The recess includes a bottom surface and a groove extending at least partially along the bottom surface of the recess. A cover is disposed within the recess and covers at least a portion of the groove. The groove is configured to channel a cooling fluid therethrough to cool the cover.

Plant nuclei can contain extensive grooves and invaginations

NASA Technical Reports Server (NTRS)

Collings, D. A.; Carter, C. N.; Rink, J. C.; Scott, A. C.; Wyatt, S. E.; Allen, N. S.; Brown, C. S. (Principal Investigator)

2000-01-01

Plant cells can exhibit highly complex nuclear organization. Through dye-labeling experiments in untransformed onion epidermal and tobacco culture cells and through the expression of green fluorescent protein targeted to either the nucleus or the lumen of the endoplasmic reticulum/nuclear envelope in these cells, we have visualized deep grooves and invaginations into the large nuclei of these cells. In onion, these structures, which are similar to invaginations seen in some animal cells, form tubular or planelike infoldings of the nuclear envelope. Both grooves and invaginations are stable structures, and both have cytoplasmic cores containing actin bundles that can support cytoplasmic streaming. In dividing tobacco cells, invaginations seem to form during cell division, possibly from strands of the endoplasmic reticulum trapped in the reforming nucleus. The substantial increase in nuclear surface area resulting from these grooves and invaginations, their apparent preference for association with nucleoli, and the presence in them of actin bundles that support vesicle motility suggest that the structures might function both in mRNA export from the nucleus and in protein import from the cytoplasm to the nucleus.

Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes

PubMed Central

Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

2017-01-01

Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed. PMID:28335425

Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes.

PubMed

Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

2017-03-14

Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed.

Two pad axially grooved hydrostatic bearing

NASA Technical Reports Server (NTRS)

San Andres, Luis A. (Inventor)

1995-01-01

A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

Development of optimized, graded-permeability axial groove heat pipes

NASA Technical Reports Server (NTRS)

Kapolnek, Michael R.; Holmes, H. Rolland

1988-01-01

Heat pipe performance can usually be improved by uniformly varying or grading wick permeability from end to end. A unique and cost effective method for grading the permeability of an axial groove heat pipe is described - selective chemical etching of the pipe casing. This method was developed and demonstrated on a proof-of-concept test article. The process improved the test article's performance by 50 percent. Further improvement is possible through the use of optimally etched grooves.

A narrow-band k-distribution model with single mixture gas assumption for radiative flows

NASA Astrophysics Data System (ADS)

Jo, Sung Min; Kim, Jae Won; Kwon, Oh Joon

2018-06-01

In the present study, the narrow-band k-distribution (NBK) model parameters for mixtures of H2O, CO2, and CO are proposed by utilizing the line-by-line (LBL) calculations with a single mixture gas assumption. For the application of the NBK model to radiative flows, a radiative transfer equation (RTE) solver based on a finite-volume method on unstructured meshes was developed. The NBK model and the RTE solver were verified by solving two benchmark problems including the spectral radiance distribution emitted from one-dimensional slabs and the radiative heat transfer in a truncated conical enclosure. It was shown that the results are accurate and physically reliable by comparing with available data. To examine the applicability of the methods to realistic multi-dimensional problems in non-isothermal and non-homogeneous conditions, radiation in an axisymmetric combustion chamber was analyzed, and then the infrared signature emitted from an aircraft exhaust plume was predicted. For modeling the plume flow involving radiative cooling, a flow-radiation coupled procedure was devised in a loosely coupled manner by adopting a Navier-Stokes flow solver based on unstructured meshes. It was shown that the predicted radiative cooling for the combustion chamber is physically more accurate than other predictions, and is as accurate as that by the LBL calculations. It was found that the infrared signature of aircraft exhaust plume can also be obtained accurately, equivalent to the LBL calculations, by using the present narrow-band approach with a much improved numerical efficiency.

Stabilizing gas bearing in free piston machines

NASA Technical Reports Server (NTRS)

Dhar, Manmohan (Inventor)

1992-01-01

In a free piston engine, to reduce dynamic loads on the reciprocating elements caused by a time varying pressure gradient across the gas bearing and close clearance seals provided therein, drain galleries are incorporated at the ends of the gas bearings to isolate the same, and circumferentially spaced grooves are incorporated in the close clearance seal region.

Stabilizing Gas Bearings In Free-Piston Machines

NASA Technical Reports Server (NTRS)

Dhar, Manmohan

1995-01-01

Gas bearings and clearance seals between pistons and cylinders in free-piston machines designed to reduce undesired dynamic forces and torques on pistons, gas bearings, and cylinders. Circumferential grooves and drain galleries added to piston or cylinder in improved design. Provides stabilization without significant reduction in length of seal, or significant increase in leakage and consequent reduction of efficiency.

The role of the bicipital groove in tendopathy of the long biceps tendon.

PubMed

Pfahler, M; Branner, S; Refior, H J

1999-01-01

Long biceps tendon disease is often underrated but plays an important role in anterior shoulder pain. We studied prospectively the anatomy of the bicipital groove and its relationship to clinical symptoms. Sixty-seven consecutive patients were investigated by mutual ultrasonography and radiographs of the intertubercular groove. All images were scrutinized for biceps tendon status (ultrasonography) and groove anatomy (radiography). Thirty-seven patients (21 male, 16 female, average age 48 years) had chronic anterior shoulder pain, and 30 patients (16 male, 14 female, average age 46 years) served as a control group. In 28 shoulders we found sonographic signs of tendovaginitis, and in 14 we found degenerative changes. The mean age of patients with pathologic conditions of the long biceps tendon was 40 years, significantly lower than that of the complete study group. The x-ray films revealed a great variation in the medial and total opening angle of the groove, whereas width, depth, and humeral head diameter showed sex-related differences. Radiologic signs of groove degeneration correlated in 43.6% with biceps tendon disease on the sonogram. Our study revealed statistically significant correlations between groove anatomy and long biceps tendon disease, which should be considered more while shoulder problems are evaluated.

Spontaneous formation of multiple land-and-groove structures of silica thin films

NASA Astrophysics Data System (ADS)

Takeda, Yasuhiko; Matsuoka, Yoriko; Motohiro, Tomoyoshi

1999-05-01

We found spontaneous formation of microscopic multiple land-and-groove structures of silica thin films. Silica and nickel were simultaneously deposited onto glass substrates from two opposite oblique directions to form columnar structures of silica among which nickel nanoparticles were embedded. Then nickel was dissolved in hydrochloric acid solution. After the dissolution of the nickel particles the columns of silica became very unstable and coalesced to form the multiple land-and-groove structures. The grooves are oriented to the direction perpendicular to the two deposition directions. The distances between the neighboring grooves are fairly uniform, and can be controlled between several hundred nanometers and several microns by changing the film thickness and the ratio of the nickel deposition rate to the silica deposition rate. The process found here may propose a new class of micro fabrication techniques in contrast to the artificial photolithography.

Forming Ganymede’s grooves at smaller strain: Toward a self-consistent local and global strain history for Ganymede

USGS Publications Warehouse

Bland, Michael T.; McKinnon, W. B.

2015-01-01

The ubiquity of tectonic features formed in extension, and the apparent absence of ones formed in contraction, has led to the hypothesis that Ganymede has undergone global expansion in its past. Determining the magnitude of such expansion is challenging however, and extrapolation of locally or regionally inferred strains to global scales often results in strain estimates that exceed those based on global constraints. Here we use numerical simulations of groove terrain formation to develop a strain history for Ganymede that is generally consistent at local, regional, and global scales. These simulations reproduce groove-like amplitudes, wavelengths, and average slopes at modest regional extensions (10–15%). The modest strains are more consistent with global constraints on Ganymede’s expansion. Yet locally, we also find that surface strains can be much larger (30–60%) in the same simulations, consistent with observations of highly-extended impact craters. Thus our simulations satisfy both the smallest-scale and largest-scale inferences of strain on Ganymede. The growth rate of the topography is consistent with (or exceeds) predictions of analytical models, and results from the use of a non-associated plastic rheology that naturally permits localization of brittle failure (plastic strain) into linear fault-like shear zones. These fault-like zones are organized into periodically-spaced graben-like structures with stepped, steeply-dipping faults. As in previous work, groove amplitudes and wavelengths depend on both the imposed heat flux and surface temperature, but because our brittle strength increases with depth, we find (for the parameters explored) that the growth rate of topography is initially faster for lower heat flows. We observe a transition to narrow rifting for higher heat flows and larger strains, which is a potential pathway for breakaway margin or band formation.

Method of forming grooves in the [011] crystalline direction

NASA Technical Reports Server (NTRS)

Marinelli, Donald Paul (Inventor)

1977-01-01

An A-B etchant is applied to a (100) surface of a body of semiconductor material, a portion of which along the (100) surface of the body is either gallium arsenide or gallium aluminum arsenide. The etchant is applied for at least 15 seconds at a temperature of approximately 80.degree. C. The A-B etchant is a solution by weight percent of 47.5%, water, 0.2% silver nitrate, 23.8% chromium trioxide and 28.5% of a 48% aqueous solution of hydrofluoric acid. As a result of the application of the A-B etchant a pattern of elongated etch pits form having their longitudinal axes along the [011] crystalline direction. Grooves are formed in the body at a surface opposite the (100) surface on which was applied the etchant. The grooves are formed along the [011] crystalline direction by aligning the longitudinal axes of the grooves with the longitudinal axes of the etch pits.

Study on the Correlation Between Dynamical Behavior and Friction/Wear Mechanism Under the Effect of Grooves

NASA Astrophysics Data System (ADS)

Zhu, Z. Y.; Mo, J. L.; Wang, D. W.; Zhao, J.; Zhu, M. H.; Zhou, Z. R.

2018-04-01

In this work, the interfacial friction and wear and vibration characteristics are studied by sliding a chromium bearing steel ball (AISI 52100) over both multi-grooved and single-grooved forged steel disks (20CrMnMo) at low and high rotating speeds in order to reveal the effect mechanism of groove-textured surface on tribological behaviors. The results show that the grooves modify the contact state of the ball and the disk at the contact interface. This consequently causes variations in the normal displacement, normal force, and friction force signals. The changes in these three signals become more pronounced with increasing groove width at a low speed. The collision behavior between the ball and the groove increase the amplitude of vibration acceleration at a high speed. The test results suggest that grooves with appropriate widths could trap wear debris on the ball surface while avoiding a strong collision between the disk and the ball, resulting in an improvement in the wear states.

Generating topography through tectonic deformation of ice lithospheres: Simulating the formation of Ganymede's grooves

NASA Astrophysics Data System (ADS)

Bland, M. T.; McKinnon, W. B.

2010-12-01

Ganymede’s iconic topography offers clues to both the satellite’s thermal evolution, and the mechanics of tectonic deformation on icy satellites. Much of Ganymede’s surface consists of bright, young terrain, with a characteristic morphology dubbed “groove terrain”. As reviewed in Pappalardo et al. (2004), in Jupiter - The Planet, Satellites, and Magnetosphere (CUP), grooved terrain consists of sets of quasi-parallel, periodically-spaced, ridges and troughs. Peak-to-trough groove amplitudes are ~500 m, with low topographic slopes (~5°). Groove spacing is strongly periodic within a single groove set, ranging from 3-17 km; shorter wavelength deformation is also apparent in high-resolution images. Grooved terrain likely formed via unstable extension of Ganymede’s ice lithosphere, which was deformed into periodically-spaced pinches and swells, and accommodated by tilt-block normal faulting. Analytical models of unstable extension support this formation mechanism [Dombard and McKinnon 2001, Icarus 154], but initial numerical models of extending ice lithospheres struggled to produce large-amplitude, groove-like deformation [Bland and Showman 2007, Icarus 189]. Here we present simulations that reproduce many of the characteristics of Ganymede’s grooves [Bland et al. 2010, Icarus in press]. By more realistically simulating the decrease in material strength after initial fault development, our model allows strain to become readily localized into discrete zones. Such strain localization leads to the formation of periodic structures with amplitudes of 200-500 m, and wavelengths of 3-20 km. The morphology of the deformation depends on both the lithospheric thermal gradient, and the rate at which material strength decreases with increasing plastic strain. Large-amplitude, graben-like structures form when material weakening occurs rapidly with increasing strain, while lower-amplitude, periodic structures form when the ice retains its strength. Thus, extension can

Readout signals calculated for near-field optical pickups with land and groove recording.

PubMed

Saito, K; Kishima, K; Ichimura, I

2000-08-10

Optical disk readout signals with a solid immersion lens (SIL) and the land-groove recording technique are calculated by use of a simplified vector-diffraction theory. In this method the full vector-diffraction theory is applied to calculate the diffracted light from the initial state of the disk, and the light scattered from the recorded marks is regarded as a perturbation. Using this method, we confirmed that the land-groove recording technique is effective as a means of cross-talk reduction even when the numerical aperture is more than 1. However, the top surface of the disk under the SIL must be flat, or the readout signal from marks recorded on a groove decays when the optical depth of the groove is greater than lambda/8.

Modeling and Analysis of the Static Characteristics and Dynamic Responses of Herringbone-grooved Thrust Bearings

NASA Astrophysics Data System (ADS)

Yu, Yunluo; Pu, Guang; Jiang, Kyle

2017-12-01

This paper describes a theoretical investigation of static and dynamic characteristics of herringbone-grooved air thrust bearings. Firstly, Finite Difference Method (FDM) and Finite Volume Method (FVM) are used in combination to solve the non-linear Reynolds equation and to find the pressure distribution of the film and the total loading capacity of the bearing. The influence of design parameters on air film gap characteristics, including the air film thickness, depth of the groove and rotating speed, are analyzed based on the FDM model. The simulation results show that hydrostatic thrust bearings can achieve a better load capacity with less air consumption than herringbone grooved thrust bearings at low compressibility number; herringbone grooved thrust bearings can achieve a higher load capacity but with more air consumption than hydrostatic thrust bearing at high compressibility number; herringbone grooved thrust bearings would lose stability at high rotating speeds, and the stability increases with the depth of the grooves.

Dynamic film thickness between bubbles and wall in a narrow channel

NASA Astrophysics Data System (ADS)

Ito, Daisuke; Damsohn, Manuel; Prasser, Horst-Michael; Aritomi, Masanori

2011-09-01

The present paper describes a novel technique to characterize the behavior of the liquid film between gas bubbles and the wall in a narrow channel. The method is based on the electrical conductance. Two liquid film sensors are installed on both opposite walls in a narrow rectangular channel. The liquid film thickness underneath the gas bubbles is recorded by the first sensor, while the void fraction information is obtained by measuring the conductance between the pair of opposite sensors. Both measurements are taken on a large two-dimensional domain and with a high speed. This makes it possible to obtain the two-dimensional distribution of the dynamic liquid film between the bubbles and the wall. In this study, this method was applied to an air-water flow ranging from bubbly to churn regimes in the narrow channel with a gap width of 1.5 mm.

Channel plasmon-polariton guiding by subwavelength metal grooves.

PubMed

Bozhevolnyi, Sergey I; Volkov, Valentyn S; Devaux, Eloïse; Ebbesen, Thomas W

2005-07-22

We report on realization of channel plasmon-polariton (CPP) propagation along a subwavelength metal groove. Using imaging with a near-field microscope and end-fire coupling with a tapered fiber connected to a tunable laser at telecommunication wavelengths (1425-1620 nm), we demonstrate low-loss (propagation length approximately 100 microm) and well-confined (mode width approximately 1.1 microm) CPP guiding along a triangular 0.6 microm-wide and 1 microm-deep groove in gold. We develop a simple model based on the effective-index method that accounts for the main features of CPP guiding and provides a clear physical picture of this phenomenon.

Optimal Tempo for Groove: Its Relation to Directions of Body Movement and Japanese nori

PubMed Central

Etani, Takahide; Marui, Atsushi; Kawase, Satoshi; Keller, Peter E.

2018-01-01

The tendency for groove-based music to induce body movements has been linked to multiple acoustical factors. However, it is unclear how or whether tempo affects groove, although tempo significantly affects other aspects of music perception. To address this issue, the present study investigated effects of tempo, specific rhythmic organizations of patterns, and syncopation on groove and the induction of the sensation of wanting to move. We focused on the directions of body movement in particular by taking into account nori, which is an indigenous Japanese musical term used not only synonymously with groove, but also as a spatial metaphor indicating vertical or horizontal movement directions. Thus, the present study explored how groove was felt and defined, as well as how musical factors induced the sensation of wanting to move in cross-cultural context. A listening experiment was conducted using drum breaks as stimuli. Stimuli consisted of various rhythm patterns at six tempi from 60 to 200 BPM. The main findings are that: (1) an optimal tempo for groove existed for drum breaks at around 100–120 BPM, (2) an optimal tempo existed for the sensation of wanting to move the body in specific directions (i.e., back-and-forth and side-to-side), (3) groove and nori shared a similar concept of wanting to move but differed on several points (i.e., association with sense of pulse and fast tempo). Overall, the present study suggests that there is an optimal tempo for body movement related to groove. This finding has implications for the use of music or rhythmic stimuli to induce smooth motion in rehabilitation, therapy, or dance. PMID:29692747

Mathematical modeling of photovoltaic thermal PV/T system with v-groove collector

NASA Astrophysics Data System (ADS)

Zohri, M.; Fudholi, A.; Ruslan, M. H.; Sopian, K.

2017-07-01

The use of v-groove in solar collector has a higher thermal efficiency in references. Dropping the working heat of photovoltaic panel was able to raise the electrical efficiency performance. Electrical and thermal efficiency were produced by photovoltaic thermal (PV/T) system concurrently. Mathematical modeling based on steady-state thermal analysis of PV/T system with v-groove was conducted. With matrix inversion method, the energy balance equations are explained by means of the investigative method. The comparison results show that in the PV/T system with the V-groove collector is higher temperature, thermal and electrical efficiency than other collectors.

U-Groove aluminum weld strength improvement

NASA Technical Reports Server (NTRS)

Verderaime, V.; Vaughan, R.

1996-01-01

Though butt-welds are among the most preferred joining methods in aerostructures, their strength dependence on inelastic mechanics is generally the least understood. This study investigated experimental strain distributions across a thick aluminum U-grooved weld and identified two weld process considerations for improving the multipass weld strength. The extreme thermal expansion and contraction gradient of the fusion heat input across the groove tab thickness produces severe peaking, which induces bending under uniaxial loading. The filler strain-hardening decreased with increasing filler pass sequence, producing the weakest welds on the last pass side. Current welding schedules unknowingly compound these effects which reduce the weld strength. A depeaking index model was developed to select filler pass thicknesses, pass numbers, and sequences to improve depeaking in the welding process. The intent is to combine the strongest weld pass side with the peaking induced bending tension to provide a more uniform stress and stronger weld under axial tensile loading.

Topography and geologic characteristics of aeolian grooves in the south polar layered deposits of Mars

USGS Publications Warehouse

Bridges, N.T.; Herkenhoff, K. E.

2002-01-01

The topographic and geologic characteristics of grooves and groove-like features in the south polar layered deposits near the Mars Polar Lander/Deep Space 2 landing sites are evaluated using Mariner 9 images and their derived photoclinometry, normalized using Mars Orbiter Laser Altimeter data. Although both Mariner 9 and Viking images of the south polar layered deposits were available at the time of this study, Mariner 9 images of the grooves were selected because they were generally of higher resolution than Viking images. The dimensions and slopes of the grooves, together with orientations that nearly match the strongest winds predicted in the Martian Global Circulation Model and directions inferred from other wind indicators, suggest that they formed by aeolian scour of an easily erodible surface. Most grooves are symmetric and V-shaped in transverse profile, inconsistent with an origin involving extensional brittle deformation. Although the grooves strike along slopes and terraces of the south polar layered deposits, the variable depths and lack of terracing within the grooves themselves indicate that any stratigraphy in the uppermost 100 m of the polar layered deposits is composed of layers of similar, and relatively low, resistance. The grooves do not represent landing hazards at the scale of the Mariner 9 images (72-86 m/pixel) and therefore probably would not have affected Mars Polar Lander and Deep Space 2, had they successfully reached the surface. ?? 2002 Elsevier Science (USA).

The Effect of Expert Performance Microtiming on Listeners' Experience of Groove in Swing or Funk Music

PubMed Central

Senn, Olivier; Kilchenmann, Lorenz; von Georgi, Richard; Bullerjahn, Claudia

2016-01-01

This study tested the influence of expert performance microtiming on listeners' experience of groove. Two professional rhythm section performances (bass/drums) in swing and funk style were recorded, and the performances' original microtemporal deviations from a regular metronomic grid were scaled to several levels of magnitude. Music expert (n = 79) and non-expert (n = 81) listeners rated the groove qualities of stimuli using a newly developed questionnaire that measures three dimensions of the groove experience (Entrainment, Enjoyment, and the absence of Irritation). Findings show that music expert listeners were more sensitive to microtiming manipulations than non-experts. Across both expertise groups and for both styles, groove ratings were high for microtiming magnitudes equal or smaller than those originally performed and decreased for exaggerated microtiming magnitudes. In particular, both the fully quantized music and the music with the originally performed microtiming pattern were rated equally high on groove. This means that neither the claims of PD theory (that microtiming deviations are necessary for groove) nor the opposing exactitude hypothesis (that microtiming deviations are detrimental to groove) were supported by the data. PMID:27761117

The Effect of Expert Performance Microtiming on Listeners' Experience of Groove in Swing or Funk Music.

PubMed

Senn, Olivier; Kilchenmann, Lorenz; von Georgi, Richard; Bullerjahn, Claudia

2016-01-01

This study tested the influence of expert performance microtiming on listeners' experience of groove. Two professional rhythm section performances (bass/drums) in swing and funk style were recorded, and the performances' original microtemporal deviations from a regular metronomic grid were scaled to several levels of magnitude. Music expert ( n = 79) and non-expert ( n = 81) listeners rated the groove qualities of stimuli using a newly developed questionnaire that measures three dimensions of the groove experience ( Entrainment, Enjoyment , and the absence of Irritation ). Findings show that music expert listeners were more sensitive to microtiming manipulations than non-experts. Across both expertise groups and for both styles, groove ratings were high for microtiming magnitudes equal or smaller than those originally performed and decreased for exaggerated microtiming magnitudes. In particular, both the fully quantized music and the music with the originally performed microtiming pattern were rated equally high on groove. This means that neither the claims of PD theory (that microtiming deviations are necessary for groove) nor the opposing exactitude hypothesis (that microtiming deviations are detrimental to groove) were supported by the data.

Hemoglobin encapsulation in vesicles retards NO and CO binding and O2 release when perfused through narrow gas-permeable tubes.

PubMed

Sakai, Hiromi; Okuda, Naoto; Sato, Atsushi; Yamaue, Tatsuya; Takeoka, Shinji; Tsuchida, Eishun

2010-03-01

Intravenous administration of cell-free Hb induces vasoconstriction and circulatory disorders, presumably because of the intrinsic affinities to endogenous nitric oxide (NO) and carbon monoxide (CO) as vasorelaxation factors and because of the facilitated O(2) release that might induce autoregulatory vasoconstriction. We examined these gas reactions when Hb-containing solutions of four kinds were perfused through artificial narrow tubes at a practical Hb concentration (10 g/dl). Purified Hb solution, polymerized bovine Hb (Poly(B)Hb), encapsulated Hb [Hb-vesicles (HbV), 279 nm], and red blood cells (RBCs) were perfused through a gas-permeable narrow tube (25 microm inner diameter) at 1 mm/s centerline velocity. The level of reactions was determined microscopically based on the visible-light absorption spectrum of Hb. When the tube was immersed in NO and CO atmospheres, both NO binding and CO binding of deoxygenated Hb (deoxy-Hb) and Poly(B)Hb in the tube was faster than those of HbV and RBCs, and HbV and RBCs showed almost identical binding rates. When the tube was immersed in a N(2) atmosphere, oxygenated Hb and Poly(B)Hb showed much faster O(2) release than did HbV and RBCs. Poly(B)Hb showed a faster reaction than Hb because of the lower O(2) affinity of Poly(B)Hb than Hb. The diffusion process of the particles was simulated using Navier-Stokes and Maxwell-Stefan equations. Results clarified that small Hb (6 nm) diffuses laterally and mixes rapidly. However, the large-dimension HbV shows no such rapid diffusion. The purely physicochemical differences in diffusivity of the particles and the resulting reactivity with gas molecules are one factor inducing biological vasoconstriction of Hb-based oxygen carriers.

Design, Construction, Demonstration and Delivery of an Automated Narrow Gap Welding System.

DTIC Science & Technology

1983-03-31

evaluated on the Narrow Gap welding system. By using the combinational qas shielding assembly, it is now possible to reduce the gas flow rates to a value...AD-A145 496 DESIGN CONSTRUCTION DEMONSTRATION AND DE IVER OF AN AUTOMATED NARROW GAP WELDING SYSTEM(U) CRC AUTOMATIC WELDING CO HODSTON SX 31 MAR 83...STANDARDS-963 - A CRC REPORT NO. NAV A/W 7 0PHASE 3 REPORT ON SDESIGN, CONSTRUCTION, DEMONSTRATION AND DELIVERY OF AN AUTOMATED NARROW GAP WELDING

Tharsis Grooved Channel

NASA Image and Video Library

2002-12-04

The Tharsis Montes region on Mars is a major center of volcanic and tectonic activity. The channel in this image from NASA Mars Odyssey is west of the relatively small volcano called Biblis Patera although it shows no obvious relationship to that volcano. Instead, it may be related to the more distant, but more massive volcano Olympus Mons to the north. The channel may have hosted flowing lava at one time but now contains a material that has eroded into an impressive ridge-and-groove pattern. These features may be yardangs, landforms produced from the erosion by wind of sedimentary material. http://photojournal.jpl.nasa.gov/catalog/PIA04020

Terahertz absorber based on Fano-like resonance of inverted quadrangular frustum pyramid metal grooves and sensor application

NASA Astrophysics Data System (ADS)

Yu, Yingying; Sun, Bo

2018-07-01

We investigate the multi-resonance coupling of inverted quadrangular frustum pyramid (IQFP) groove metal arrays at terahertz frequencies. The surface plasmon resonance (SPR) and groove resonance are induced, resulting in resonance coupling. The dipole of the groove resonance drives the quadrupole of the SPR and creates a sharp Fano-like resonance. The effects of geometry parameters including the width (at the bottom) and height are analyzed in detail. The results show that with the decrease in the sidewall slope of the groove, the confinement of the groove region on the electromagnetic field decreases, thereby increasing the resonance coupling. The Fano-like resonance is enhanced. The sensitivity and quality factor are discussed. The results show that the Fano-like resonance has high sensitivity and quality factor. With the increase in the sidewall slope of the groove, the sensitivity increases, and the quality factor decreases. The results show that the Fano-like resonance of IQFP groove metal arrays has a significant potential for biological monitoring and sensing.

Modifications of Ti-6Al-4V surfaces by direct-write laser machining of linear grooves

NASA Astrophysics Data System (ADS)

Ulerich, Joseph P.; Ionescu, Lara C.; Chen, Jianbo; Soboyejo, Winston O.; Arnold, Craig B.

2007-02-01

As patients who receive orthopedic implants live longer and opt for surgery at a younger age, the need to extend the in vivo lifetimes of these implants has grown. One approach is to pattern implant surfaces with linear grooves, which elicit a cellular response known as contact guidance. Lasers provide a unique method of generating these surface patterns because they are capable of modifying physical and chemical properties over multiple length scales. In this paper we explore the relationship between surface morphology and laser parameters such as fluence, pulse overlap (translation distance), number of passes, and machining environment. We find that using simple procedures involving multiple passes it is possible to manipulate groove properties such as depth, shape, sub-micron roughness, and chemical composition of the Ti-6Al-4V oxide layer. Finally, we demonstrate this procedure by machining several sets of grooves with the same primary groove parameters but varied secondary characteristics. The significance of the secondary groove characteristics is demonstrated by preliminary cell studies indicating that the grooves exhibit basic features of contact guidance and that the cell proliferation in these grooves are significantly altered despite their similar primary characteristics. With further study it will be possible to use specific laser parameters during groove formation to create optimal physical and chemical properties for improved osseointegration.

U-shaped micro-groove fiber based on femtosecond laser processing for humidity sensing

NASA Astrophysics Data System (ADS)

Fu, Gui; Ma, Li-li; Su, Fu-fang; Shi, Meng

2018-05-01

A novel optical fiber sensor with a U-shaped micro-groove structure ablated by femtosecond laser on single-mode fiber for measuring air relative humidity (RH) is reported in this paper. In order to improve the accuracy of sensor, a graphene oxide (GO)/polyvinyl alcohol (PVA) composite film is coated on the surface of micro-groove structure. In the U-shaped micro-groove structure, the remaining core and micro-cavity in the micro-groove make up two major optical propagation paths, forming a Mach-Zehnder interferometer (MZI). The sensor has a good linear response within the RH range of 30%—85%, and the maximum sensitivity can reach 0.638 1 nm/%RH. The effect of temperature on the overall performance of the humidity sensor is also investigated. As a new type of all-fiber device, the sensor shows excellent sensitivity and stability.

Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading.

PubMed

Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Sasaki, Muneteru; Inoue, Maaya; Yasutake, Munenori; Sawase, Takashi

2017-01-15

The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with -60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50N, 3Hz, 1800 cycles, 2days/week) at 12weeks after surgery for 8weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not -60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry. Although the paradigm of bone quality has shifted from density-based assessments to structural evaluations of bone, clarifying bone quality based on structural bone evaluations remains challenging in implant dentistry. In this study, we firstly demonstrated that the optimal design of dental implant necks improved bone quality defined as osteocytes and the preferential alignment degree of biological

The resistance of high frequency inductive welded pipe to grooving corrosion in salt water

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

Duran, C.; Triess, E.; Herbsleb, G.

1986-09-01

When exposed to neutral, salt-containing waters, electric resistant welded pipe in carbon and low alloy steels with increased sulfur contents may suffer preferential corrosion attack in the weld area. Because of its appearance, this type of corrosion is called grooving corrosion. The susceptibility to grooving corrosion may be determined and quantitatively described by means of an accelerated potentiostatic exposure test. The importance of type, concentration, and temperature of the electrolytic solution; potential; test duration; and the sulfur content of the steel in the accelerated corrosion test and the susceptibility of steels to grooving corrosion are described. Line pipe in highmore » frequency inductive (HFI) welded carbon and low alloy steels are resistant to grooving corrosion particularly because of their low sulfur content.« less

Effect of narrow band nonuniformity on unsteady heat up of water vapor under radiation-conduction combined heat transfer

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

Okamoto, Tatsuyuki; Tanaka, Tomohiro; Morimune, Atsushi

Effect of narrow band nonuniformity on unsteady heat up process of water vapor under radiation-conduction combined heat transfer is examined by comparing the result of numerical simulations with and without incorporation of narrow band nonuniformity. The authors propose a rational and comprehensive computational approach for incorporating the narrow band nonuniformity into numerical simulations of radiative heat transfer when the considered field is nonisothermal. Results of examination exhibited that the contribution of radiative heat transfer to the heat up rate of water vapor may be almost twice overestimated, if the narrow band nonuniformity effect is neglected. Separate analyses of radiative energymore » attributed to wall emission and gas emission clarified that the absorption of wall emission is overestimated and, on the contrary, the absorption of radiation energy emitted by water vapor itself is underestimated if the narrow band nonuniformity is neglected. The reason why such over- or under-estimation is induced is understood by examining the influence of line overlap parameter on the transmittance averaged within a narrow band. Smaller value of line overlap parameter {gamma}/d means more violent narrow band nonuniformity. The broken lines show the narrow band transmittance for flat incident power spectrum, and the solid lines show that for the radiative emission from the absorbing gas itself. It is also clarified that the disregard of the narrow band nonuniformity give rise to serious error in the estimation of absorption rate of wall and gas emission even in the case where the disregard of narrow band nonuniformity bring little change to the temperature distribution. The results illustrated in this paper suggest that the narrow band nonuniformity should not be neglected.« less

Comparative evaluation of three heat transfer enhancement strategies in a grooved channel

NASA Astrophysics Data System (ADS)

Herman, C.; Kang, E.

Results of a comparative evaluation of three heat transfer enhancement strategies for forced convection cooling of a parallel plate channel populated with heated blocks, representing electronic components mounted on printed circuit boards, are reported. Heat transfer in the reference geometry, the asymmetrically heated parallel plate channel, is compared with that for the basic grooved channel, and the same geometry enhanced by cylinders and vanes placed above the downstream edge of each heated block. In addition to conventional heat transfer and pressure drop measurements, holographic interferometry combined with high-speed cinematography was used to visualize the unsteady temperature fields in the self-sustained oscillatory flow. The locations of increased heat transfer within one channel periodicity depend on the enhancement technique applied, and were identified by analyzing the unsteady temperature distributions visualized by holographic interferometry. This approach allowed gaining insight into the mechanisms responsible for heat transfer enhancement. Experiments were conducted at moderate flow velocities in the laminar, transitional and turbulent flow regimes. Reynolds numbers were varied in the range Re=200-6500, corresponding to flow velocities from 0.076 to 2.36m/s. Flow oscillations were first observed between Re=1050 and 1320 for the basic grooved channel, and around Re=350 and 450 for the grooved channels equipped with cylinders and vanes, respectively. At Reynolds numbers above the onset of oscillations and in the transitional flow regime, heat transfer rates in the investigated grooved channels exceeded the performance of the reference geometry, the asymmetrically heated parallel plate channel. Heat transfer in the grooved channels enhanced with cylinders and vanes showed an increase by a factor of 1.2-1.8 and 1.5-3.5, respectively, when compared to data obtained for the basic grooved channel; however, the accompanying pressure drop penalties also

User's Manual for Thermal Analysis Program of Axially Grooved Heat Pipe (HTGAP)

NASA Technical Reports Server (NTRS)

Kamotani, Y.

1978-01-01

A computer program that numerically predicts the steady state temperature distribution inside an axially grooved heat pipe wall for a given groove geometry and working fluid under various heat input and output modes is described. The program computes both evaporator and condenser film coefficients. The program is able to handle both axisymmetric and nonaxisymmetric heat transfer cases. Non-axisymmetric heat transfer results either from non-uniform input at the evaporator or non-uniform heat removal from the condenser, or from both. The presence of a liquid pool in the condenser region under one-g condition also causes non-axisymmetric heat transfer, and its effect on the pipe wall temperature distribution is included in the present program. The hydrodynamic aspect of an axially grooved heat pipe is studied in the Groove Analysis Program (GAP). The present thermal analysis program assumes that the GAP program (or other similar programs) is run first so that the heat transport limit and optimum fluid charge of the heat pipe are known a priori.

Fracture toughness determination using spiral-grooved cylindrical specimen and pure torsional loading

DOEpatents

Wang, Jy-An; Liu, Kenneth C.

2003-07-08

A method for determining fracture toughness K.sub.IC of materials ranging from metallic alloys, brittle ceramics and their composites, and weldments. A cylindrical specimen having a helical V-groove with a 45.degree. pitch is subjected to pure torsion. This loading configuration creates a uniform tensile-stress crack-opening mode, and a transverse plane-strain state along the helical groove. The full length of the spiral groove is equivalent to the thickness of a conventional compact-type specimen. K.sub.IC values are determined from the fracture torque and crack length measured from the test specimen using a 3-D finite element program (TOR3D-KIC) developed for the purpose. In addition, a mixed mode (combined tensile and shear stress mode) fracture toughness value can be determined by varying the pitch of the helical groove. Since the key information needed for determining the K.sub.IC value is condensed in the vicinity of the crack tip, the specimen can be significantly miniaturized without the loss of generality.

Gradient rotating outer volume excitation (GROOVE): A novel method for single-shot two-dimensional outer volume suppression.

PubMed

Powell, Nathaniel J; Jang, Albert; Park, Jang-Yeon; Valette, Julien; Garwood, Michael; Marjańska, Małgorzata

2015-01-01

To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume. Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4T horizontal bore magnet equipped with a TEM coil. Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal. GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory that can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression). © 2014 Wiley Periodicals, Inc.

Major versus minor groove DNA binding of a bisarginylporphyrin hybrid molecule: A molecular mechanics investigation

NASA Astrophysics Data System (ADS)

Gresh, Nohad; Perrée-fauvet, Martine

1999-03-01

On the basis of theoretical computations, we have recently synthesised [Perrée-Fauvet, M. and Gresh, N., Tetrahedron Lett., 36 (1995) 4227] a bisarginyl conjugate of a tricationic porphyrin (BAP), designed to target, in the major groove of DNA, the d(GGC GCC)2 sequence which is part of the primary binding site of the HIV-1 retrovirus site [Wain-Hobson, S. et al., Cell, 40 (1985) 9]. In the theoretical model, the chromophore intercalates at the central d(CpG)2 step and each of the arginyl arms targets O6/N7belonging to guanine bases flanking the intercalation site. Recent IR and UV-visible spectroscopic studies have confirmed the essential features of these theoretical predictions [Mohammadi, S. et al., Biochemistry, 37 (1998) 6165]. In the present study, we compare the energies of competing intercalation modes of BAP to several double-stranded oligonucleotides, according to whether one, two or three N- methylpyridinium rings project into the major groove. Correspondingly, three minor groove binding modes were considered, the arginyl arms now targeting N3, O2 sites belonging to the purine or pyrimidine bases flanking the intercalation site. This investigation has shown that: (i) in both the major and minor grooves, the best-bound complexes have the three N-methylpyridinium rings in the groove opposite to that of the phenyl group bearing the arginyl arms; (ii) major groove binding is preferred over minor groove binding by a significant energy (29 kcal/mol); and (iii) the best-bound sequence in the major groove is d(GGC GCC)2 with two successive guanines upstream from the intercalation. On the other hand, due to the flexibility of the arginyl arms, other GC-rich sequences have close binding energies, two of them being less stable than it by less than 8 kcal/mol. These results serve as the basis for the design of derivatives of BAP with enhanced sequence selectivities in the major groove.

Spiral groove seal. [for hydraulic rotating shaft

NASA Technical Reports Server (NTRS)

Ludwig, L. P. (Inventor)

1973-01-01

Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove pattern produces a pumping action toward the fluid when the shaft rotates which prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear.

Longitudinal afterbody grooves and shoulder radiusing for low-speed bluff body drag reduction

NASA Technical Reports Server (NTRS)

Howard, F. G.; Quass, B. F.; Weinstein, L. M.; Bushnell, D. M.

1981-01-01

A new low-speed drag reduction approach is proposed which employs longitudinal surface V-shaped grooves cutting through the afterbody shoulder region. The test Reynolds number range was from 20,000 to 200,000 based on undisturbed free-stream flow and a body diameter of 6.08 cm. The V-grooves are shown to be most effective in reducing drag when the afterbody shoulder radius is zero. Reductions in drag of up to 33% have been measured for this condition. For large shoulder radius, the grooves are only effective at the lower Reynolds numbers of the test.

Polarizing beam splitter of deep-etched triangular-groove fused-silica gratings.

PubMed

Zheng, Jiangjun; Zhou, Changhe; Feng, Jijun; Wang, Bo

2008-07-15

We investigated the use of a deep-etched fused-silica grating with triangular-shaped grooves as a highly efficient polarizing beam splitter (PBS). A triangular-groove PBS grating is designed at a wavelength of 1550 nm to be used in optical communication. When it is illuminated in Littrow mounting, the transmitted TE- and TM-polarized waves are mainly diffracted in the minus-first and zeroth orders, respectively. The design condition is based on the average differences of the grating mode indices, which is verified by using rigorous coupled-wave analysis. The designed PBS grating is highly efficient over the C+L band range for both TE and TM polarizations (>97.68%). It is shown that such a triangular-groove PBS grating can exhibit a higher diffraction efficiency, a larger extinction ratio, and less reflection loss than the binary-phase fused-silica PBS grating.

Some effects of grooved runway configurations on aircraft tire braking traction under flooded runway conditions

NASA Technical Reports Server (NTRS)

Byrdsong, T. A.

1973-01-01

An experimental investigation was conducted to study the effect of grooved runway configurations on aircraft tire braking traction on flooded runway surfaces. The investigation was performed, utilizing size 49 x 17, type VII, aircraft tires with an inflation pressure of 170 lb per square inch at ground speeds up to approximately 120 knots. The results of this investigation indicate that when the runway is flooded, grooved surfaces provide better braking traction than an ungrooved surface and, in general, the level of braking traction was found to improve as the tire bearing pressure was increased because of an increase in the groove area of either the surface or the tire tread. Rounding the groove edges tended to degrade the tire braking capability from that developed on the same groove configuration with sharp edges. Results also indicate that braking friction coefficients for the test tires and runway surfaces decreased as ground speed was increased because of the hydroplaning effects.

Influence of edge conditions on material ejection from periodic grooves in laser shock-loaded tin

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

Rességuier, T. de; Roland, C.; Prudhomme, G.

2016-05-14

In a material subjected to high dynamic compression, the breakout of a shock wave at a rough free surface can lead to the ejection of high velocity debris. Anticipating the ballistic properties of such debris is a key safety issue in many applications involving shock loading, including pyrotechnics and inertial confinement fusion experiments. In this paper, we use laser driven shocks to investigate particle ejection from calibrated grooves of micrometric dimensions and approximately sinusoidal profile in tin samples, with various boundary conditions at the groove edges, including single groove and periodic patterns. Fast transverse shadowgraphy provides ejection velocities after shockmore » breakout. They are found to depend not only on the groove depth and wavelength, as predicted theoretically and already observed in the past, but also, unexpectedly, on the edge conditions, with a jet tip velocity significantly lower in the case of a single groove than behind a periodic pattern.« less

What Components Comprise the Measurement of the Tibial Tuberosity-Trochlear Groove Distance in a Patellar Dislocation Population?

PubMed

Tensho, Keiji; Akaoka, Yusuke; Shimodaira, Hiroki; Takanashi, Seiji; Ikegami, Shota; Kato, Hiroyuki; Saito, Naoto

2015-09-02

The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercle transfer; however, to our knowledge, no studies have verified whether this distance is strongly affected by tubercle lateralization at the proximal part of the tibia. We hypothesized that the tibial tuberosity-trochlear groove distance is mainly affected by tibial tubercle lateralization at the proximal part of the tibia. Forty-four patients with a history of patellar dislocation and forty-four age and sex-matched controls were analyzed with use of computed tomography. The tibial tuberosity-trochlear groove distance, tibial tubercle lateralization, trochlear groove medialization, and knee rotation were measured and were compared between the patellar dislocation group and the control group. The association between the tibial tuberosity-trochlear groove distance and three other parameters was calculated with use of the Pearson correlation coefficient and partial correlation analysis. There were significant differences in the tibial tuberosity-trochlear groove distance (p < 0.001) and knee rotation (p < 0.001), but there was no difference in the tibial tubercle lateralization (p = 0.13) and trochlear groove medialization (p = 0.08) between the patellar dislocation group and the control group. The tibial tuberosity-trochlear groove distance had no linear correlation with tubercle lateralization (r = 0.21) or groove medialization (r = -0.15); however, knee rotation had a good positive correlation in the patellar dislocation group (r = 0.62). After adjusting for the remaining parameters, knee rotation strongly correlated with the tibial tuberosity-trochlear groove distance (r = 0.69, p < 0.001), whereas tubercle lateralization showed moderate significant correlations in the patellar dislocation group (r = 0.42; p = 0.005). Because the tibial tuberosity-trochlear groove distance is affected more by knee rotation than by tubercle malposition, its use as an indicator for

Preliminary Test Results of a Non-Contacting Finger Seal on a Herringbone-Grooved Rotor

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.; Degado, Irebert R.

2008-01-01

Low leakage, non-contacting finger seals have potential to reduce gas turbine engine specific fuel consumption by 2 to 3 percent and to reduce direct operating costs by increasing the time between engine overhauls. A non-contacting finger seal with concentric lift-pads operating adjacent to a test rotor with herringbone grooves was statically tested at 300, 533, and 700 K inlet air temperatures at pressure differentials up to 576 kPa. Leakage flow factors were approximately 70 percent less than state-of-the-art labyrinth seals. Leakage rates are compared to first order predictions. Initial spin tests at 5000 rpm, 300 K inlet air temperature and pressure differentials to 241 kPa produced no measurable wear.

Levitation and locomotion on an air-table of plates with herringbone grooves

NASA Astrophysics Data System (ADS)

Hinch, John; de Maleprade, Helene

2017-11-01

Recent experiments in ESPCI in Paris and numerical simulations in Nano- and Microfluidics in Darmstadt have shown that plates with herringbone grooves in their base are accelerated on an air-table in the direction that the chevron grooves point. A simple two-dimensional model is constructed of the air flow down a channel with pressure controlled influx across the lower boundary. Limiting cases are considered of low and high Reynolds numbers, and of small and large pressure drop down the channel compared with the pressure drop across the porous plate. The levitation and locomotion forces are calculated. A prediction is made for the locomotive acceleration which avoids the complications of the shorter grooves which exit the front and back edges.

Structure of a Pheromone Receptor-Associated Mhc Molecule With An Open And Empty Groove

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

Olson, R.; Huey-Tubman, K.E.; Dulac, C.

2006-10-06

Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-bindingmore » MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.« less

DRhoGEF2 and Diaphanous Regulate Contractile Force during Segmental Groove Morphogenesis in the Drosophila Embryo

PubMed Central

Mulinari, Shai; Barmchi, Mojgan Padash

2008-01-01

Morphogenesis of the Drosophila embryo is associated with dynamic rearrangement of the actin cytoskeleton mediated by small GTPases of the Rho family. These GTPases act as molecular switches that are activated by guanine nucleotide exchange factors. One of these factors, DRhoGEF2, plays an important role in the constriction of actin filaments during pole cell formation, blastoderm cellularization, and invagination of the germ layers. Here, we show that DRhoGEF2 is equally important during morphogenesis of segmental grooves, which become apparent as tissue infoldings during mid-embryogenesis. Examination of DRhoGEF2-mutant embryos indicates a role for DRhoGEF2 in the control of cell shape changes during segmental groove morphogenesis. Overexpression of DRhoGEF2 in the ectoderm recruits myosin II to the cell cortex and induces cell contraction. At groove regression, DRhoGEF2 is enriched in cells posterior to the groove that undergo apical constriction, indicating that groove regression is an active process. We further show that the Formin Diaphanous is required for groove formation and strengthens cell junctions in the epidermis. Morphological analysis suggests that Dia regulates cell shape in a way distinct from DRhoGEF2. We propose that DRhoGEF2 acts through Rho1 to regulate acto-myosin constriction but not Diaphanous-mediated F-actin nucleation during segmental groove morphogenesis. PMID:18287521

Spectrally-Narrowed Emissions from Organic Crystals Having a One-Dimensional Grating on Their Surface.

PubMed

Yamamoto, Hiroyuki; Obara, Keiji; Higashihara, Shohei; Obama, Yuki; Yamao, Takeshi; Hotta, Shu

2016-04-01

We have succeeded in directly engraving one-dimensional diffraction gratings on the surface of organic semiconducting oligomer crystals by using focused ion beam (FIB) lithography and laser ablation (LA) methods. The FIB method enabled us to shape the gratings with varying periods down to ~150 nm. With the LA method a large-area grating with a ~500-nm period was readily accessible. All the above crystals indicated spectrally-narrowed emission (SNE) lines even in the case of shallow groove depths ~2-4 nm. In particular, we definitively observed the SNE pertinent to the first-order diffraction with the crystal having the diffraction grating of a 148.3-nm average period. The present results indicate utility of the built-in gratings that can directly be fabricated on the surface of the crystals.

Erosion of a grooved surface caused by impact of particle-laden flow

NASA Astrophysics Data System (ADS)

Jung, Sohyun; Yang, Eunjin; Kim, Ho-Young

2016-11-01

Solid erosion can be a life-limiting process for mechanical elements in erosive environments, thus it is of practical importance in many industries such as construction, mining, and coal conversion. Erosion caused by particle-laden flow occurs through diverse mechanisms, such as cutting, plastic deformation, brittle fracture, fatigue and melting, depending on particle velocity, total particle mass and impingement angle. Among a variety of attempts to lessen erosion, here we investigate the effectiveness of millimeter-sized grooves on the surface. By experimentally measuring the erosion rates of smooth and triangular-grooved surfaces under various impingement angles, we find that erosion can be significantly reduced within a finite range of impingement angles. We show that such erosion resistance is attributed to the swirls of air within grooves and the differences in erosive strength of normal and slanted impact. In particular, erosion is mitigated when we increase the effective area under normal impact causing plastic deformation and fracture while decreasing the area under slanted impact that cuts the surface to a large degree. Our quantitative model for the erosion rate of grooved surfaces considering the foregoing effects agrees with the measurement results.

Correcting Nasojugal Groove with Autologous Cultured Fibroblast Injection: A Pilot Study.

PubMed

Moon, Kyung-Chul; Lee, Hyun-Su; Han, Seung-Kyu; Chung, Ho-Yun

2018-06-01

A new commercial drug that contains autologous cultured fibroblasts has been developed and approved by the United States Food and Drug Administration for improving the appearance of nasolabial folds. However, the treatment requires three sessions every 3-6 weeks. It is known that the skin overlying the nasojugal groove is thinner, and the wrinkle is generally shallower than nasolabial folds. Therefore, we hypothesized that the nasojugal groove could be improved by just one treatment session. Therefore, the purpose of this study was to evaluate the efficacy and safety of autologous cultured fibroblast injection to correct nasojugal grooves. Forty-six subjects with nasojugal grooves were enrolled in this study. They were injected with autologous cultured fibroblasts or placebo in one session. Blinded evaluators and subjects assessed the efficacy using a validated wrinkle assessment scale at 4, 12, and 24 weeks after the injection. Information of adverse events was collected at each visit. Based on the evaluators' assessment at 24 weeks after the injection, 76% of subjects treated with autologous cultured fibroblasts showed improvement whereas 0% of subjects treated with placebo showed improvement (P < 0.0001). Based on self-assessment at 24 weeks after the injection, 72% of subjects treated with autologous cultured fibroblasts and 45% of subjects treated with placebo showed improvement (P = 0.0662). There were no serious adverse events related to autologous cultured fibroblast injection. Autologous cultured fibroblast injection might be effective and safe to correct nasojugal grooves. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Plant Nuclei Can Contain Extensive Grooves and InvaginationsW⃞W⃞

PubMed Central

Collings, David A.; Carter, Crystal N.; Rink, Jochen C.; Scott, Amie C.; Wyatt, Sarah E.; Allen, Nina Strömgren

2000-01-01

Plant cells can exhibit highly complex nuclear organization. Through dye-labeling experiments in untransformed onion epidermal and tobacco culture cells and through the expression of green fluorescent protein targeted to either the nucleus or the lumen of the endoplasmic reticulum/nuclear envelope in these cells, we have visualized deep grooves and invaginations into the large nuclei of these cells. In onion, these structures, which are similar to invaginations seen in some animal cells, form tubular or planelike infoldings of the nuclear envelope. Both grooves and invaginations are stable structures, and both have cytoplasmic cores containing actin bundles that can support cytoplasmic streaming. In dividing tobacco cells, invaginations seem to form during cell division, possibly from strands of the endoplasmic reticulum trapped in the reforming nucleus. The substantial increase in nuclear surface area resulting from these grooves and invaginations, their apparent preference for association with nucleoli, and the presence in them of actin bundles that support vesicle motility suggest that the structures might function both in mRNA export from the nucleus and in protein import from the cytoplasm to the nucleus. PMID:11148288

Thermal performance comparison of oscillating heat pipes with and without helical micro-grooves

NASA Astrophysics Data System (ADS)

Qu, Jian; Li, Xiaojun; Xu, Qian; Wang, Qian

2017-11-01

This paper presents an experimental investigation to compare the thermal performance of three closed loop oscillating heat pipes (OHPs) with and without internal helical microgrooves at vertical and horizontal orientations. All of these OHPs were made from copper tubes and have three turns with lengths of 70, 230 and 110 mm at the evaporator, adiabatic and condenser sections, respectively. Deionized water was used as the working fluid at a volumetric filling ratio of 50%. The internal diameters (IDs) of two smooth-tube OHPs are 4.0 and 4.8 mm, respectively, and the internal diameter of micro-grooved OHP without groove structures is about 4.5 mm. Experimental results demonstrated that the addition of groove structures make the OHP remarkably outperform smooth-tube OHPs in both effective thermal conductivity and thermal resistance. The thermal resistance of vertically-oriented micro-grooved OHP could be lowered to 0.057 °C/W associated with an effective thermal conductivity of 6.1 × 104 W/ (m·K) at the input heat flux of 3.8 × 104 W/m2. Compared to smooth-tube OHPs, preliminary mechanism analysis reveals that local heat transfer coefficients both at the heating and cooling sections of micro-grooved OHP could be significantly improved. Moreover, enhanced liquid backflow to the evaporator due to microgroove-induced capillarity is also responsible for the OHP performance enhancement.

A morphometric assessment and classification of coral reef spur and groove morphology

NASA Astrophysics Data System (ADS)

Duce, S.; Vila-Concejo, A.; Hamylton, S. M.; Webster, J. M.; Bruce, E.; Beaman, R. J.

2016-07-01

Spurs and grooves (SaGs) are a common and important feature of coral reef fore slopes worldwide. However, they are difficult to access and hence their morphodynamics and formation are poorly understood. We use remote sensing, with extensive ground truthing, to measure SaG morphometrics and environmental factors at 11,430 grooves across 17 reefs in the southern Great Barrier Reef, Australia. We revealed strong positive correlations between groove length, orientation and wave exposure with longer, more closely-spaced grooves oriented easterly reflecting the dominant swell regime. Wave exposure was found to be the most important factor controlling SaG distribution and morphology. Gradient of the upper reef slope was also an important limiting factor, with SaGs less likely to develop in steeply sloping (> 5°) areas. We used a subset of the morphometric data (11 reefs) to statistically define four classes of SaG. This classification scheme was tested on the remaining six reefs. SaGs in the four classes differ in morphology, groove substrate and coral cover. These differences provide insights into SaG formation mechanisms with implications to reef platform growth and evolution. We hypothesize SaG formation is dominated by coral growth processes at two classes and erosion processes at one class. A fourth class may represent relic features formed earlier in the Holocene transgression. The classes are comparable with SaGs elsewhere, suggesting the classification could be applied globally with the addition of new classes if necessary. While further research is required, we show remotely sensed SaG morphometrics can provide useful insights into reef platform evolution.

[A case of groove pancreatitis (segmental form) presented with obstructive jaundice associated with pancreatobiliary maljunction].

PubMed

Hiramatsu, Kiyoshi; Ito, Takaaki; Kaburagi, Daisuke; Arai, Riki; Maruyama, Hideki; Naganuma, Atsushi; Kato, Kenji

2008-09-01

A 52-year-old-man was admitted to our hospital for obstructive jaundice. Percutaneous transhepatic cholangio drainage (PTCD) and endscopic retrograde cholangiopancreatography (ERCP) were performed, and pointed out stenosis of lower common bile duct (CBD) and pancreatobiliary maljunction. Brushing cytology of this lesion was negative for malignancy. CT and MRI revealed chronic inflammatory change in groove lesion with no mass formation suggesting tumor. So we diagnosed groove pancreatitis (segmental form) associated with pancreatobiliary maljunction, and operation (resection of the bile duct and biliary reconstruction by Roux-en-Y) was done. Resected specimen was revealed stenosis of the bile duct formed by fibrous tissue with no malignancy compatible to groove pancreatitis pathologically. This is first reported case of groove pancreatits associated with pancreatobiliary maljunction.

Formation of Ganymede's Grooved Terrain by Convection-Driven Resurfacing

NASA Astrophysics Data System (ADS)

Hammond, N. P.; Barr, A. C.

2013-12-01

Over half the surface of Ganymede, Jupiter's largest icy moon, is covered in grooved terrain, which is composed of 10-100 km wide swaths of sub-parallel ridges and troughs [1]. Convection in Ganymede's ice shell was originally suggested as a driving mechanism for grooved terrain formation [2] but subsequent work has argued that convective stresses were too weak to deform the surface [3] and that Ganymede's ice shell was thin and conductive during groove terrain formation [4]. However, the heat flow [5] and strain rate [6] inferred for grooved terrain formation resemble the conditions observed at the active Enceladus South Polar Terrain (SPT), where 'sluggish lid' convection may be occurring [7]. During 'sluggish lid' convection, thermal buoyancy stresses exceed the lithospheric yield stress, allowing convection to reach the surface and drive deformation [8]. Previous work shows that the heat flows and strain rates associated with sluggish lid convection are consistent with the observed heat flow and surface age of the Enceladus SPT [7, 9]. Here we use numerical models of convection in Ganymede's ice shell to show that convection can provide the heat flow and strain rate inferred for grooved terrain formation. We use the finite element model CITCOM [10] to model convection for a wide range of ice shell conditions. We use a newtonian temperature-dependent viscosity consistent with deformation by volume diffusion [11]. We impose a limited viscosity contrast between the surface and base of the ice shell to mimic the effect of an upper surface whose yield stress is less than the critical stress for sluggish lid convection [7, 12] due to impact fracturing [13], tidal flexing, and/or shallow tidal heating. We find that ice shells 10 to 80 km thick are consistent with the heat flow and strain rate inferred for grooved terrain formation. Regions above convective upwellings are consistent with conditions inferred at groove lanes. Regions above downwellings are consistent

An Analysis of the Effects of Chip-groove Geometry on Machining Performance Using Finite Element Methods

NASA Astrophysics Data System (ADS)

Ee, K. C.; Dillon, O. W.; Jawahir, I. S.

2004-06-01

This paper discusses the influence of major chip-groove parameters of a cutting tool on the chip formation process in orthogonal machining using finite element (FE) methods. In the FE formulation, a thermal elastic-viscoplastic material model is used together with a modified Johnson-Cook material law for the flow stress. The chip back-flow angle and the chip up-curl radius are calculated for a range of cutting conditions by varying the chip-groove parameters. The analysis provides greater understanding of the effectiveness of chip-groove configurations and points a way to correlate cutting conditions with tool-wear when machining with a grooved cutting tool.

U-Groove Aluminum Weld Strength Improvement

NASA Technical Reports Server (NTRS)

Verderaime, V.; Vaughan, R.

1997-01-01

Though butt-welds are among the most preferred joining methods in aerostructures, their strength dependence on inelastic mechanics is generally the least understood. This study investigated experimental strain distributions across a thick aluminum U-grooved weld and identified two weld process considerations for improving the multipass weld strength. One is the source of peaking in which the extreme thermal expansion and contraction gradient of the fusion heat input across the groove tab thickness produces severe angular distortion that induces bending under uniaxial loading. The other is the filler strain hardening decreasing with increasing filler pass sequences, producing the weakest welds on the last weld pass side. Both phenomena are governed by weld pass sequences. Many industrial welding schedules unknowingly compound these effects, which reduce the weld strength. A depeaking index model was developed to select filler pass thickness, pass numbers, and sequences to improve depeaking in the welding process. The result was to select the number and sequence of weld passes to reverse the peaking angle such as to combine the strongest weld pass side with the peaking induced bending tension component side to provide a more uniform stress and stronger weld under axial tensile loading.

Investigation of mucosal pattern of gastric antrum using magnifying narrow-band imaging in patients with chronic atrophic fundic gastritis.

PubMed

Yamasaki, Yasushi; Uedo, Noriya; Kanzaki, Hiromitsu; Kato, Minoru; Hamada, Kenta; Aoi, Kenji; Tonai, Yusuke; Matsuura, Noriko; Kanesaka, Takashi; Yamashina, Takeshi; Akasaka, Tomofumi; Hanaoka, Noboru; Takeuchi, Yoji; Higashino, Koji; Ishihara, Ryu; Tomita, Yasuhiko; Iishi, Hiroyasu

2017-01-01

Magnifying narrow-band imaging (M-NBI) can reportedly help predict the presence and distribution of atrophy and intestinal metaplasia in the gastric corpus. However, the micro-mucosal pattern of the antrum shown by M-NBI differs from that of the corpus. We studied the distribution and histology of the micro-mucosal pattern in the antrum based on magnifying endoscopy. Endoscopic images of the greater curvature of the antrum were evaluated in 50 patients with chronic atrophic fundic gastritis (CAFG). The extent of CAFG was evaluated by autofluorescence imaging. The micro-mucosal pattern was evaluated by M-NBI and classified into groove and white villiform types. The localization of white villiform type mucosa was classified into three types in relation to the areae gastricae : null, central, and segmental types. Biopsies were taken from regions showing different micro-mucosal patterns. Associations among the extent of CAFG, micro-mucosal pattern, and histology were examined. As the extent of CAFG increased, the proportion of white villiform type mucosa increased, whereas that of groove type mucosa decreased (P=0.022). In patients with extensive CAFG, most of the areae gastricae was composed of the segmental or central type of white villiform type mucosa (P=0.044). The white villiform type mucosa had significantly higher grades of atrophy (P=0.002) and intestinal metaplasia (P<0.001) than did the groove type mucosa. White villiform type mucosa is indicative of atrophy and intestinal metaplasia in the gastric antrum. It extends to the whole or central part of the areae gastricae as CAFG becomes more extensive.

The narrow pulse approximation and long length scale determination in xenon gas diffusion NMR studies of model porous media

NASA Technical Reports Server (NTRS)

Mair, R. W.; Sen, P. N.; Hurlimann, M. D.; Patz, S.; Cory, D. G.; Walsworth, R. L.

2002-01-01

We report a systematic study of xenon gas diffusion NMR in simple model porous media, random packs of mono-sized glass beads, and focus on three specific areas peculiar to gas-phase diffusion. These topics are: (i) diffusion of spins on the order of the pore dimensions during the application of the diffusion encoding gradient pulses in a PGSE experiment (breakdown of the narrow pulse approximation and imperfect background gradient cancellation), (ii) the ability to derive long length scale structural information, and (iii) effects of finite sample size. We find that the time-dependent diffusion coefficient, D(t), of the imbibed xenon gas at short diffusion times in small beads is significantly affected by the gas pressure. In particular, as expected, we find smaller deviations between measured D(t) and theoretical predictions as the gas pressure is increased, resulting from reduced diffusion during the application of the gradient pulse. The deviations are then completely removed when water D(t) is observed in the same samples. The use of gas also allows us to probe D(t) over a wide range of length scales and observe the long time asymptotic limit which is proportional to the inverse tortuosity of the sample, as well as the diffusion distance where this limit takes effect (approximately 1-1.5 bead diameters). The Pade approximation can be used as a reference for expected xenon D(t) data between the short and the long time limits, allowing us to explore deviations from the expected behavior at intermediate times as a result of finite sample size effects. Finally, the application of the Pade interpolation between the long and the short time asymptotic limits yields a fitted length scale (the Pade length), which is found to be approximately 0.13b for all bead packs, where b is the bead diameter. c. 2002 Elsevier Sciences (USA).

The narrow pulse approximation and long length scale determination in xenon gas diffusion NMR studies of model porous media.

PubMed

Mair, R W; Sen, P N; Hürlimann, M D; Patz, S; Cory, D G; Walsworth, R L

2002-06-01

We report a systematic study of xenon gas diffusion NMR in simple model porous media, random packs of mono-sized glass beads, and focus on three specific areas peculiar to gas-phase diffusion. These topics are: (i) diffusion of spins on the order of the pore dimensions during the application of the diffusion encoding gradient pulses in a PGSE experiment (breakdown of the narrow pulse approximation and imperfect background gradient cancellation), (ii) the ability to derive long length scale structural information, and (iii) effects of finite sample size. We find that the time-dependent diffusion coefficient, D(t), of the imbibed xenon gas at short diffusion times in small beads is significantly affected by the gas pressure. In particular, as expected, we find smaller deviations between measured D(t) and theoretical predictions as the gas pressure is increased, resulting from reduced diffusion during the application of the gradient pulse. The deviations are then completely removed when water D(t) is observed in the same samples. The use of gas also allows us to probe D(t) over a wide range of length scales and observe the long time asymptotic limit which is proportional to the inverse tortuosity of the sample, as well as the diffusion distance where this limit takes effect (approximately 1-1.5 bead diameters). The Padé approximation can be used as a reference for expected xenon D(t) data between the short and the long time limits, allowing us to explore deviations from the expected behavior at intermediate times as a result of finite sample size effects. Finally, the application of the Padé interpolation between the long and the short time asymptotic limits yields a fitted length scale (the Padé length), which is found to be approximately 0.13b for all bead packs, where b is the bead diameter. c. 2002 Elsevier Sciences (USA).

[Microsurgical removal of olfactory groove meningiomas].

PubMed

Liang, Ri-Sheng; Zhou, Liang-Fu; Mao, Ying; Zhang, Rong; Yang, Wei-Zhong

2011-01-01

To explore an effective method for further improving the surgical results of treatment of olfactory groove meningiomas. Sixty seven cases of olfactory groove meningiomas were treated by microneurosurgery, among which fifty seven were de novo cases, eight were recurrent tumors and the other two re-recurrent cases. Modified Derome approach was used in 12 cases, bilateral subfrontal approach in 28 cases, modified pterional approach in 21 cases and unilateral subfrontal approach in six cases. Tumors were resected microsurgically with radical removal of invaded dura, bone, and paranasal sinus mucosa. Reconstruction was performed in patients with skull base defect. Simpson grade I removal was accomplished in 59 cases, grade II in seven cases and grade IV in one case. Among 57 patients with de novo tumor, Simpson I resection was accomplished in 54 cases. Postoperative rhinorrhea and intracranial infection occurred in one case and was cured after temporal lumbar CSF drainage and antibiotic therapy. Two patients (2.9%) died within one month after operation, i.e.one aged patient of heart failure and the other of severe hypothalamus complication. Forty seven patients (72.3%) were followed up from one to ten years with an average of five years and four months. With the exception of two cases died, among the alive 45 patients, there were only three patients with tumor recurrence, which had undergone Simpson II or IV tumor resection. No recurrence was found in cases with Simpson I tumor removal. Previous blurred vision was not improved in three patients, hemiparalysis in two patients, and the other patients recovered well, resuming previous jobs or being able to take care themselves. Total tumor removal (Simpson I) should be the surgical goal for treatment of olfactory groove meningiomas, especially for de novo cases. An appropriate approach is fundamental in the effort to remove an OGM totally. Appropriate anterior skull base reconstruction with vascularized material is

Cycle time improvement for plastic injection moulding process by sub groove modification in conformal cooling channel

NASA Astrophysics Data System (ADS)

Kamarudin, K.; Wahab, M. S.; Batcha, M. F. M.; Shayfull, Z.; Raus, A. A.; Ahmed, Aqeel

2017-09-01

Mould designers have been struggling for the improvement of the cooling system performance, despite the fact that the cooling system complexity is physically limited by the fabrication capability of the conventional tooling methods. However, the growth of Solid Free Form Technology (SFF) allow the mould designer to develop more than just a regular conformal cooling channel. Numerous researchers demonstrate that conformal cooling channel was tremendously given significant result in the improvement of productivity and quality in the plastic injection moulding process. This paper presents the research work that applies the passive enhancement method in square shape cooling channel to enhance the efficiency of cooling performance by adding the sub groove to the cooling channel itself. Previous design that uses square shape cooling channel was improved by adding various numbers of sub groove to meet the best sub groove design that able reduced the cooling time. The effect of sub groove design on cooling time was investigated by Autodesk Modlflow Insight software. The simulation results showed that the various sub groove designs give different values to ejection time. The Design 7 showed the lowest value of ejection time with 24.3% increment. The addition of sub groove significantly increased a coolant velocity and a rate of heat transfer from molten plastic to coolant.

Comparison of computational methods to model DNA minor groove binders.

PubMed

Srivastava, Hemant Kumar; Chourasia, Mukesh; Kumar, Devesh; Sastry, G Narahari

2011-03-28

There has been a profound interest in designing small molecules that interact in sequence-selective fashion with DNA minor grooves. However, most in silico approaches have not been parametrized for DNA ligand interaction. In this regard, a systematic computational analysis of 57 available PDB structures of noncovalent DNA minor groove binders has been undertaken. The study starts with a rigorous benchmarking of GOLD, GLIDE, CDOCKER, and AUTODOCK docking protocols followed by developing QSSR models and finally molecular dynamics simulations. In GOLD and GLIDE, the orientation of the best score pose is closer to the lowest rmsd pose, and the deviation in the conformation of various poses is also smaller compared to other docking protocols. Efficient QSSR models were developed with constitutional, topological, and quantum chemical descriptors on the basis of B3LYP/6-31G* optimized geometries, and with this ΔT(m) values of 46 ligands were predicted. Molecular dynamics simulations of the 14 DNA-ligand complexes with Amber 8.0 show that the complexes are stable in aqueous conditions and do not undergo noticeable fluctuations during the 5 ns production run, with respect to their initial placement in the minor groove region.

Binding to the DNA Minor Groove by Heterocyclic Dications: From AT Specific Monomers to GC Recognition with Dimers

PubMed Central

Nanjunda, Rupesh; Wilson, W. David

2012-01-01

Compounds that bind in the DNA minor groove have provided critical information on DNA molecular recognition, they have found extensive uses in biotechnology and they are providing clinically useful drugs against diseases as diverse as cancer and sleeping sickness. This review focuses on the development of clinically useful heterocyclic diamidine minor groove binders. These compounds have shown us that the classical model for minor groove binding in AT DNA sequences must be expanded in several ways: compounds with nonstandard shapes can bind strongly to the groove, water can be directly incorporated into the minor groove complex in an interfacial interaction, and the compounds can form cooperative stacked dimers to recognize GC and mixed AT/GC base pair sequences. PMID:23255206

Design of nano-groove photonic crystal cavities in lithium niobate.

PubMed

Li, Yihang; Wang, Cheng; Loncar, Marko

2015-06-15

We propose a novel design of photonic-crystal nanobeam cavities in lithium niobate (LN) for both TE and TM modes, addressing problems associated with tilted sidewalls, which commonly result from dry etching. Using optimized periodical nano-groove structures, the proposed devices could achieve quality factors as high as 3.9×10(6) with a modal volume of 5.0 (λ/n)3. We also show that such a design is promising for applications in nonlinear optics by theoretically predicting the efficiencies for electro-optic modulation and second-harmonic generation. The proposed nano-groove structures and design rules could also be applied for other material platforms that possess tilted sidewalls.

DNA minor groove electrostatic potential: influence of sequence-specific transitions of the torsion angle gamma and deoxyribose conformations.

PubMed

Zhitnikova, M Y; Shestopalova, A V

2017-11-01

The structural adjustments of the sugar-phosphate DNA backbone (switching of the γ angle (O5'-C5'-C4'-C3') from canonical to alternative conformations and/or C2'-endo → C3'-endo transition of deoxyribose) lead to the sequence-specific changes in accessible surface area of both polar and non-polar atoms of the grooves and the polar/hydrophobic profile of the latter ones. The distribution of the minor groove electrostatic potential is likely to be changing as a result of such conformational rearrangements in sugar-phosphate DNA backbone. Our analysis of the crystal structures of the short free DNA fragments and calculation of their electrostatic potentials allowed us to determine: (1) the number of classical and alternative γ angle conformations in the free B-DNA; (2) changes in the minor groove electrostatic potential, depending on the conformation of the sugar-phosphate DNA backbone; (3) the effect of the DNA sequence on the minor groove electrostatic potential. We have demonstrated that the structural adjustments of the DNA double helix (the conformations of the sugar-phosphate backbone and the minor groove dimensions) induce changes in the distribution of the minor groove electrostatic potential and are sequence-specific. Therefore, these features of the minor groove sizes and distribution of minor groove electrostatic potential can be used as a signal for recognition of the target DNA sequence by protein in the implementation of the indirect readout mechanism.

Unified design of sinusoidal-groove fused-silica grating.

PubMed

Feng, Jijun; Zhou, Changhe; Cao, Hongchao; Lu, Peng

2010-10-20

A general design rule of deep-etched subwavelength sinusoidal-groove fused-silica grating as a highly efficient polarization-independent or polarization-selective device is studied based on the simplified modal method, which shows that the device structure depends little on the incident wavelength, but mainly on the ratio of groove depth to incident wavelength and the ratio of wavelength to grating period. These two ratios could be used as the design guidelines for wavelength-independent structure from deep ultraviolet to far infrared. The optimized grating profile with a different function as a polarizing beam splitter, a polarization-independent two-port beam splitter, or a polarization-independent grating with high efficiency of -1st order is obtained at a wavelength of 1064 nm, and verified by using the rigorous coupled-wave analysis. The performance of the sinusoidal grating is better than a conventional rectangular one, which could be useful for practical applications.

Dance, Music, Meter and Groove: A Forgotten Partnership.

PubMed

Fitch, W Tecumseh

2016-01-01

I argue that core aspects of musical rhythm, especially "groove" and syncopation, can only be fully understood in the context of their origins in the participatory social experience of dance. Musical meter is first considered in the context of bodily movement. I then offer an interpretation of the pervasive but somewhat puzzling phenomenon of syncopation in terms of acoustic emphasis on certain offbeat components of the accompanying dance style. The reasons for the historical tendency of many musical styles to divorce themselves from their dance-based roots are also briefly considered. To the extent that musical rhythms only make sense in the context of bodily movement, researchers interested in ecologically valid approaches to music cognition should make a more concerted effort to extend their analyses to dance, particularly if we hope to understand the cognitive constraints underlying rhythmic aspects of music like meter and groove.

Visualisation by high resolution synchrotron X-ray phase contrast micro-tomography of gas films on submerged superhydrophobic leaves.

PubMed

Lauridsen, Torsten; Glavina, Kyriaki; Colmer, Timothy David; Winkel, Anders; Irvine, Sarah; Lefmann, Kim; Feidenhans'l, Robert; Pedersen, Ole

2014-10-01

Floods can completely submerge terrestrial plants but some wetland species can sustain O2 and CO2 exchange with the environment via gas films forming on superhydrophobic leaf surfaces. We used high resolution synchrotron X-ray phase contrast micro-tomography in a novel approach to visualise gas films on submerged leaves of common cordgrass (Spartina anglica). 3D tomograms enabled a hitherto unmatched level of detail regarding the micro-topography of leaf gas films. Gas films formed only on the superhydrophobic adaxial leaf side (water droplet contact angle, Φ=162°) but not on the abaxial side (Φ=135°). The adaxial side of the leaves of common cordgrass is plicate with a longitudinal system of parallel grooves and ridges and the vast majority of the gas film volume was found in large ∼180μm deep elongated triangular volumes in the grooves and these volumes were connected to each neighbouring groove via a fine network of gas tubules (∼1.7μm diameter) across the ridges. In addition to the gas film retained on the leaf exterior, the X-ray phase contrast micro-tomography also successfully distinguished gas spaces internally in the leaf tissues, and the tissue porosity (gas volume per unit tissue volume) ranged from 6.3% to 20.3% in tip and base leaf segments, respectively. We conclude that X-ray phase contrast micro-tomography is a powerful tool to obtain quantitative data of exterior gas features on biological samples because of the significant difference in electron density between air, biological tissues and water. Copyright © 2014 Elsevier Inc. All rights reserved.

Features and applications of the Groove Analysis Program (GAP)

NASA Technical Reports Server (NTRS)

Ku, Jentung; Nguyen, Tu M.; Brennan, Patrick J.

1995-01-01

An IBM Personal Computer (PC) version of the Groove Analysis program (GAP) was developed to predict the steady state heat transport capability of an axially grooved heat pipe for a specified groove geometry and working fluid. In the model, the capillary limit is determined by the numerical solution of the differential equation for momentum conservation with the appropriate boundary conditions. This governing equation accounts for the hydrodynamic losses due to friction in liquid and vapor flows and due to liquid/vapor shear interaction. Back-pumping in both 0-g and 1-g is accounted for in the boundary condition at the condenser end. Slug formation in 0-g and puddle flow in 1-g are also considered in the model. At the user's discretion, the code will perform the analysis for various fluid inventories (undercharge, nominal charge, overcharge, or a fixed fluid charge) and heat pipe elevations. GAP will also calculate the minimum required heat pipe wall thickness for pressure containment at design temperatures that are greater than or lower than the critical temperature of the working fluid. This paper discusses the theory behind the development of the GAP model. It also presents the many useful and powerful capabilities of the model. Furthermore, a correlation of flight test performance data and the predictions using GAP are presented and discussed.

Morphology of the Lesser Tuberosity and Intertubercular Groove in Patients With Arthroscopically Confirmed Subscapularis and Biceps Tendon Pathology.

PubMed

Shah, Shaan H; Small, Kirstin M; Sinz, Nathan J; Higgins, Laurence D

2016-06-01

To evaluate for an association between the morphology of the lesser tuberosity and intertubercular groove and subscapularis tendon tears and biceps tendon pathology. Sixty-six patients with arthroscopically confirmed subscapularis tendon tears were compared with 59 demographically matched control patients who underwent magnetic resonance imaging or computed tomography arthrography examination of the shoulder. Measurements of the lesser tuberosity and intertubercular groove included maximum depth of the intertubercular groove, intertubercular groove depth at the midpoint of the glenoid, lesser tuberosity length, length from the top of the humeral head to the point of maximum depth of the intertubercular groove, length from the top of the humeral head to the top of the lesser tuberosity, and medial wall angle and depth. Patients with subscapularis tears showed a significantly decreased depth of the intertubercular groove at the mid glenoid (P = .01), shorter length of the lesser tuberosity (P = .002), and greater distance from the top of the humeral head to the top of the lesser tuberosity (P = .02). There was a trend toward a decreased medial wall angle (P = .07) and greater distance from the top of the humeral head to the point of maximum intertubercular groove depth (P = .06). Patients with biceps tendon pathology showed a significantly decreased depth of the intertubercular groove at the mid glenoid (P = .001), shorter length of the lesser tuberosity (P = .0003), greater distance from the top of the humeral head to the top of the lesser tuberosity (P = .01), and decreased medial wall angle (P = .01) and depth (P = .03). There are several morphologic factors related to the lesser tuberosity and intertubercular groove that are associated with both subscapularis tendon tears and biceps tendon pathology. Level III, case-control study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

QSO Narrow [OIII] Line Width and Host Galaxy Luminosity

NASA Astrophysics Data System (ADS)

Bonning, E. W.; Shields, G. A.; Salviander, S.

2004-05-01

Established correlations between galaxy bulge luminosity L, black hole mass MBH, and stellar velocity dispersion sigma in galaxies suggest a close relationship between the growth of supermassive black holes and their host galaxies. Measurements of the MBH - sigma relationship as a function of cosmic time may shed light on the origin of this relationship. One approach is to derive MBH and sigma from the widths of QSO broad and narrow lines, respectively (Shields et al. 2003, ApJ, 583, 124; Nelson 2000, ApJ, 544, L91). We investigate the utility of using the velocity of the narrow line emitting gas as a surrogate for stellar velocity dispersion in QSOs by examining host magnitudes and [OIII] line widths for low redshift QSOs. For our limited range of L, the increase in sigma with L predicted by the Faber-Jackson relation is substantially obscured by scatter. However, sigma([O III]) is consistent in the mean with host galaxy luminosity. EWB is a NASA GSRP fellow. GAS and SS are supported under Texas Advanced Research Program grant 003658-0177-2001 and NSF grant AST-0098594.

Numerical analysis of lateral illumination lightpipes using elliptical grooves

NASA Astrophysics Data System (ADS)

Sánchez-Guerrero, Guillermo E.; Viera-González, Perla M.; Martínez-Guerra, Edgar; Ceballos-Herrera, Daniel E.

2017-09-01

Lightpipes are used for illumination in applications such as back-lighting or solar cell concentrators due to the high irradiance uniformity, but its optimal design requires several parameters. This work presents a procedure to design a square lightpipe to control the light-extraction on its lateral face using commercial LEDs placed symmetrically in the lightpipe frontal face. We propose the use of grooves using total internal reflection placed successively in the same face of extraction to control the area of emission. The LED area of emission is small compared with the illuminated area, and, as expected, the lateral face total power is attenuated. These grooves reduce the optical elements in the system and can control areas of illumination. A mathematical and numerical analysis are presented to determine the dependencies on the light-extraction.

A Surface Groove Essential for Viral Bcl-2 Function During Chronic Infection In Vivo

PubMed Central

Petros, Andrew M; Nettesheim, David; van Dyk, Linda F.; Labrada, Lucia; Speck, Samuel H; Levine, Beth

2005-01-01

Antiapoptotic Bcl-2 family proteins inhibit apoptosis in cultured cells by binding BH3 domains of proapoptotic Bcl-2 family members via a hydrophobic BH3 binding groove on the protein surface. We investigated the physiological importance of the BH3 binding groove of an antiapoptotic Bcl-2 protein in mammals in vivo by analyzing a viral Bcl-2 family protein. We show that the γ-herpesvirus 68 (γHV68) Bcl-2 family protein (γHV68 v-Bcl-2), which is known to inhibit apoptosis in cultured cells, inhibits both apoptosis in primary lymphocytes and Bax toxicity in yeast. Nuclear magnetic resonance determination of the γHV68 v-Bcl-2 structure revealed a BH3 binding groove that binds BH3 domain peptides from proapoptotic Bcl-2 family members Bax and Bak via a molecular mechanism shared with host Bcl-2 family proteins, involving a conserved arginine in the BH3 peptide binding groove. Mutations of this conserved arginine and two adjacent amino acids to alanine (SGR to AAA) within the BH3 binding groove resulted in a properly folded protein that lacked the capacity of the wild-type γHV68 v-Bcl-2 to bind Bax BH3 peptide and to block Bax toxicity in yeast. We tested the physiological importance of this v-Bcl-2 domain during viral infection by engineering viral mutants encoding a v-Bcl-2 containing the SGR to AAA mutation. This mutation resulted in a virus defective for both efficient reactivation of γHV68 from latency and efficient persistent γHV68 replication. These studies demonstrate an essential functional role for amino acids in the BH3 peptide binding groove of a viral Bcl-2 family member during chronic infection. PMID:16201011

The origin of Phobos grooves from ejecta launched from impact craters on Mars: Tests of the hypothesis

NASA Astrophysics Data System (ADS)

Ramsley, Kenneth R.; Head, James W.

2013-01-01

The surface of the martian moon Phobos is characterized by parallel and intersecting grooves that bear resemblance to secondary crater chains observed on planetary surfaces. Murray (2011) has hypothesized that the main groove-forming process on Phobos is the intersection of Phobos with ejecta from primary impact events on Mars to produce chains of secondary craters. The hypothesis infers a pattern of parallel jets of ejecta, either fluidized or solidified, that break into equally-spaced fragments and disperse uniformly along-trajectory during the flight from Mars to Phobos. At the moment of impact with Phobos the dispersed fragments emplace secondary craters that are aligned along strike corresponding to the flight pattern of ejecta along trajectory. The aspects of the characteristics of grooves on Phobos cited by this hypothesis that might be explained by secondary ejecta include: their observed linearity, parallelism, planar alignment, pitted nature, change in character along strike, and a "zone of avoidance" where ejecta from Mars is predicted not to impact (Murray, 2011). To test the hypothesis we plot precise Keplerian orbits for ejecta from Mars (elliptical and hyperbolic with periapsis located below the surface of Mars). From these trajectories we: (1) set the fragment dispersion limits of ejecta patterns required to emplace the more typically well-organized parallel grooves observed in returned images from Phobos; (2) plot ranges of the ejecta flight durations from Mars to Phobos and map regions of exposure; (3) utilize the same exposure map to observe trajectory-defined ejecta exposure shadows; (4) observe hemispheric exposure in response to shorter and longer durations of ejecta flight; (5) assess the viability of ejecta emplacing the large family of grooves covering most of the northern hemisphere of Phobos; and (6) plot the arrival of parallel lines of ejecta emplacing chains of craters at oblique incident angles. We also assess the bulk volume of

Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts.

PubMed

Zhao, Yiming; Zhang, Nong; Si, Guangyao; Li, Xuehua

2018-06-02

Fiber Bragg grating (FBG) measuring bolts, as a useful tool to evaluate the behaviors of steel bolts in underground engineering, can be manufactured by gluing the FBG sensors inside the grooves, which are usually symmetrical cuts along the steel bolt rod. The selection of the cut shape and the glue types could perceivably affect the final supporting strength of the bolts. Unfortunately, the impact of cut shape and glue type on bolting strength is not yet clear. In this study, based on direct tension tests, full tensile load⁻displacement curves of rock bolts with different groove shapes were obtained and analyzed. The effects of groove shape on the bolt strength were discussed, and the stress redistribution in the cross-section of a rock bolt with different grooves was simulated using ANSYS. The results indicated that the trapezoidal groove is best for manufacturing the FBG bolt due to its low reduction of supporting strength. Four types of glues commonly used for the FBG sensors were assessed by conducting tensile tests on the mechanical testing and simulation system and the static and dynamic optical interrogators system. Using linear regression analysis, the relationship between the reflected wavelength of FBG sensors and tensile load was obtained. Practical recommendations for glue selection in engineering practice are also provided.

Safety Modification of Cam-and-Groove Hose Coupling

NASA Technical Reports Server (NTRS)

Schwindt, Paul; Littlefield, Alan

2008-01-01

A modification has been made in the mating halves of a cam-and-groove hose coupling to prevent rapid separation of the halves in the event that the cam levers are released while the fluid in the hose is pressurized. The need for this modification arises because commercial off-the-shelf cam-and-groove hose-coupling halves do not incorporate safety features to prevent separation in the pressurized state. Especially when the pressurized fluid is compressible (e.g., steam or compressed air), the separated halves can be propelled with considerable energy, causing personal injury and/or property damage. Therefore, one purpose served by the modification is to provide for venting to release compressive energy in a contained and safe manner while preventing personal injury and/or property damage. Another purpose served by the modification, during the process of connecting the coupling halves, is to ensure that the coupling halves are properly aligned before the cam levers can be locked into position.

Hydrodynamic simulations of microjetting from shock-loaded grooves

NASA Astrophysics Data System (ADS)

Roland, C.; de Rességuier, T.; Sollier, A.; Lescoute, E.; Soulard, L.; Loison, D.

2017-01-01

The interaction of a shock wave with a free surface which has geometrical defects, such as cavities or grooves, may lead to the ejection of micrometric debris at velocities of km/s. This process can be involved in many applications, like pyrotechnics or industrial safety. Recent laser shock experiments reported elsewhere in this conference have provided some insight into jet formation as well as jet tip velocities for various groove angles and shock pressures. Here, we present hydrodynamic simulations of these experiments, in both 2D and 3D geometries, using both finite element method and smoothed particle hydrodynamics. Numerical results are compared to several theoretical predictions including the Richtmyer-Meshkov instabilities. The role of the elastic-plastic behavior on jet formation is illustrated. Finally, the possibility to simulate the late stage of jet expansion and fragmentation is explored, to evaluate the mass distribution of the ejecta and their ballistic properties, still essentially unknown in the experiments.

Treatment of combined endodontic: periodontic lesion by sealing of palato-radicular groove using biodentine.

PubMed

Naik, Mayuri; de Ataide, Ida de Noronha; Fernandes, Marina; Lambor, Rajan

2014-11-01

Palatoradicular groove is a developmental anomaly which is predominantly found in maxillary lateral incisors. It provides a susceptible alcove for the progression of localised periodontal inflammation which can further cause pulpal involvement. This case report describes the successful treatment of a large periodontic - endodontic lesion usingnon surgical endodontic therapy and biodentine for the sealing of the palatoradicular groove.

Selection of optimal welding condition for GTA pulse welding in root-pass of V-groove butt joint

NASA Astrophysics Data System (ADS)

Yun, Seok-Chul; Kim, Jae-Woong

2010-12-01

In the manufacture of high-quality welds or pipeline, a full-penetration weld has to be made along the weld joint. Therefore, root-pass welding is very important, and its conditions have to be selected carefully. In this study, an experimental method for the selection of optimal welding conditions is proposed for gas tungsten arc (GTA) pulse welding in the root pass which is done along the V-grooved butt-weld joint. This method uses response surface analysis in which the width and height of back bead are chosen as quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, is used as the objective function to obtain the optimal welding conditions. In our experiments, the target values of back bead width and height are 4 mm and zero, respectively, for a V-grooved butt-weld joint of a 7-mm-thick steel plate. The optimal welding conditions could determine the back bead profile (bead width and height) as 4.012 mm and 0.02 mm. From a series of welding tests, it was revealed that a uniform and full-penetration weld bead can be obtained by adopting the optimal welding conditions determined according to the proposed method.

Development of a high-performance boiling heat exchanger by improved liquid supply to narrow channels.

PubMed

Ohta, Haruhiko; Ohno, Toshiyuki; Hioki, Fumiaki; Shinmoto, Yasuhisa

2004-11-01

A two-phase flow loop is a promising method for application to thermal management systems for large-scale space platforms handling large amounts of energy. Boiling heat transfer reduces the size and weight of cold plates. The transportation of latent heat reduces the mass flow rate of working fluid and pump power. To develop compact heat exchangers for the removal of waste heat from electronic devices with high heat generation density, experiments on a method to increase the critical heat flux for a narrow heated channel between parallel heated and unheated plates were conducted. Fine grooves are machined on the heating surface in a transverse direction to the flow and liquid is supplied underneath flattened bubbles by the capillary pressure difference from auxiliary liquid channels separated by porous metal plates from the main heated channel. The critical heat flux values for the present heated channel structure are more than twice those for a flat surface at gap sizes 2 mm and 0.7 mm. The validity of the present structure with auxiliary liquid channels is confirmed by experiments in which the liquid supply to the grooves is interrupted. The increment in the critical heat flux compared to those for a flat surface takes a maximum value at a certain flow rate of liquid supply to the heated channel. The increment is expected to become larger when the length of the heated channel is increased and/or the gravity level is reduced.

One-dimensional arrangement of nanoparticles utilizing the V-groove and cage shaped proteins

NASA Astrophysics Data System (ADS)

Ban, Takahiko; Uenuma, Mutsunori; Migita, Shinji; Okamoto, Naofumi; Ishikawa, Yasuaki; Uraoka, Yukiharu; Yamashita, Ichiro; Yamamoto, Shin-ichi

2017-06-01

The one-dimensional arrangement of nanoparticles (NPs) was performed using a V-groove and ferritins as spherical shell proteins. The V-groove was synthesized by lithography and anisotropic etching of a Si substrate. Ferritin has an outer diameter of 12 nm and an inner diameter of 6 nm, and various inorganic substances can be formed into the cavity. In this study, iron oxide, cobalt oxide, and indium oxide cores were used. The surface potential of ferritin can be changed by genetic modification. Particularly, by using Fer8-K98E, NPs could be arranged one-dimensionally onto the bottom of the V-groove. In addition, we succeeded in selectively forming a one-dimensional array of one layer, two layers, and three layers by changing the protein concentration. This experiment is expected to be applicable to various one-dimensional devices.

The behavior of the skin-friction coefficient of a turbulent boundary layer flow over a flat plate with differently configured transverse square grooves

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

Wahidi, R.; Chakroun, W.; Al-Fahed, S.

2005-11-01

Skin-friction coefficient of turbulent boundary layer flow over a smooth-wall with transverse square grooves was investigated. Four grooved-wall cases were investigated. The four grooved-wall configurations are single 5mm square grooved-wall, and 5mm square grooves spaced 10, 20 and 40 element widths apart in the streamwise direction. Laser-Doppler Anemometer (LDA) was used for the mean velocity and turbulence intensity measurements. The skin-friction coefficient determined from the velocity profile increases sharply just downstream of the groove. This overshoot is followed by an undershoot and then relaxation back to the smooth-wall value. This behavior is observed in most grooved-wall cases. Integrating the skin-frictionmore » coefficient in the streamwise direction indicates that there is an increase in the overall drag in all the grooved-wall cases.« less

Treatment of combined endodontic: periodontic lesion by sealing of palato-radicular groove using biodentine

PubMed Central

Naik, Mayuri; de Ataide, Ida de Noronha; Fernandes, Marina; Lambor, Rajan

2014-01-01

Introduction: Palatoradicular groove is a developmental anomaly which is predominantly found in maxillary lateral incisors. It provides a susceptible alcove for the progression of localised periodontal inflammation which can further cause pulpal involvement. This case report describes the successful treatment of a large periodontic – endodontic lesion usingnon surgical endodontic therapy and biodentine for the sealing of the palatoradicular groove. PMID:25506153

Extended Narrow-Line Region in Seyfert Galaxies

NASA Astrophysics Data System (ADS)

Congiu, Enrico; Contini, Marcella.; Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco; Berton, Marco; Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero

2017-10-01

We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modelling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as a) the contribution of shocks in ionizing the high velocity gas, b) the complex kinematics showed by the profile of the emission lines, c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

Mg2+ in the Major Groove Modulates B-DNA Structure and Dynamics

PubMed Central

Guéroult, Marc; Boittin, Olivier; Mauffret, Oliver; Etchebest, Catherine; Hartmann, Brigitte

2012-01-01

This study investigates the effect of Mg2+ bound to the DNA major groove on DNA structure and dynamics. The analysis of a comprehensive dataset of B-DNA crystallographic structures shows that divalent cations are preferentially located in the DNA major groove where they interact with successive bases of (A/G)pG and the phosphate group of 5′-CpA or TpG. Based on this knowledge, molecular dynamics simulations were carried out on a DNA oligomer without or with Mg2+ close to an ApG step. These simulations showed that the hydrated Mg2+ forms a stable intra-strand cross-link between the two purines in solution. ApG generates an electrostatic potential in the major groove that is particularly attractive for cations; its intrinsic conformation is well-adapted to the formation of water-mediated hydrogen bonds with Mg2+. The binding of Mg2+ modulates the behavior of the 5′-neighboring step by increasing the BII (ε-ζ>0°) population of its phosphate group. Additional electrostatic interactions between the 5′-phosphate group and Mg2+ strengthen both the DNA-cation binding and the BII character of the 5′-step. Cation binding in the major groove may therefore locally influence the DNA conformational landscape, suggesting a possible avenue for better understanding how strong DNA distortions can be stabilized in protein-DNA complexes. PMID:22844516

Analysis of transmission through slit and multiple grooves structures for biosensors

NASA Astrophysics Data System (ADS)

Kim, Bong Ho; Nakarmi, Bikash; Won, Yong Hyub

2015-03-01

We analyze the transmission property of nanostructures made on silver and gold metal for the applications in optical biosensors. Various structures such as slit only, slit groove slit, and multiple slit and groove structures are taken into account to find the effect of various physical parameters such as number of grooves, number of slits and others on the transmission of different wavelength light sources through the structure. A broad wavelength of 400 nm to 900 nm is used to analyze the transmission through the structure. With these structures and broad light source, change in transmission intensity is analyzed with the change in the refractive index. The change in refractive index of the analyte varies transmission intensity and wavelength shift at the output beam which can be used for sensing the amount of analyte such as monitoring glucose amount on blood/saliva, hydrogen peroxide and others. The detection of these analytes can be used to detect the different disease. The analysis of the transmittance through the nanostructure can be used for the detection of several disease such as diabetes and others through the saliva, blood and others non-invasively.

Users' Manual for Computer Code SPIRALI Incompressible, Turbulent Spiral Grooved Cylindrical and Face Seals

NASA Technical Reports Server (NTRS)

Walowit, Jed A.; Shapiro, Wilbur

2005-01-01

The SPIRALI code predicts the performance characteristics of incompressible cylindrical and face seals with or without the inclusion of spiral grooves. Performance characteristics include load capacity (for face seals), leakage flow, power requirements and dynamic characteristics in the form of stiffness, damping and apparent mass coefficients in 4 degrees of freedom for cylindrical seals and 3 degrees of freedom for face seals. These performance characteristics are computed as functions of seal and groove geometry, load or film thickness, running and disturbance speeds, fluid viscosity, and boundary pressures. A derivation of the equations governing the performance of turbulent, incompressible, spiral groove cylindrical and face seals along with a description of their solution is given. The computer codes are described, including an input description, sample cases, and comparisons with results of other codes.

Hydrodynamically Lubricated and Grooved Biomimetic Self-Adapting Surfaces

PubMed Central

Jackson, Robert L.; Lei, Jiang

2014-01-01

In many machines and mechanical components, there is a need for new bearing technologies to reduce friction and wear, and provide precision control of motion when the load is varied. This can be provided by electronically controlled actuators and sensors on the surfaces, but then the system reliability can be an issue. In contrast, biomimetic surfaces can be created that adapt mechanically to variations in load. This work uses numerical methods to research the use of self-adapting surfaces for bearings that are based on the deformable nature of biological materials such as articular cartilage. These surfaces are designed to change their profiles to achieve a desired behavior, without any external control. The surfaces change their profile to control the film height and tilt of the bearing to a near constant value for different loads. If the surfaces are tilted, the grooved self-adapting surfaces will also react with a larger restoring moment than a conventional grooved surface. These surfaces could be beneficial to applications where electrical systems and controls are not feasible. PMID:24956441

Hydrodynamically lubricated and grooved biomimetic self-adapting surfaces.

PubMed

Jackson, Robert L; Lei, Jiang

2014-06-04

In many machines and mechanical components, there is a need for new bearing technologies to reduce friction and wear, and provide precision control of motion when the load is varied. This can be provided by electronically controlled actuators and sensors on the surfaces, but then the system reliability can be an issue. In contrast, biomimetic surfaces can be created that adapt mechanically to variations in load. This work uses numerical methods to research the use of self-adapting surfaces for bearings that are based on the deformable nature of biological materials such as articular cartilage. These surfaces are designed to change their profiles to achieve a desired behavior, without any external control. The surfaces change their profile to control the film height and tilt of the bearing to a near constant value for different loads. If the surfaces are tilted, the grooved self-adapting surfaces will also react with a larger restoring moment than a conventional grooved surface. These surfaces could be beneficial to applications where electrical systems and controls are not feasible.

An optical biosensor using MEMS-based V-grooves

NASA Astrophysics Data System (ADS)

Tian, Ye; Ma, Xiaodong; Zou, Xiaotian; Wu, Nan; Wang, Xingwei

2011-05-01

An optical fiber biosensor featuring miniaturization, electromagnetic interference (EMI)-immunity, and flexibility is presented. The sensor was fabricated by aligning two gold-deposited optical single-mode fiber facets inside V-grooves on a silicon chip to form a Fabry-Perot (FP) cavity. The mirrors on the fiber facets were made of deposited gold (Au) films, which provided a high finesse to produce a highly sensitivity. Microelectromechanical systems (MEMS) fabrication techniques were used to precisely control the profile and angle of the V-grooves on the silicon. The biotin-terminated thiol molecule was firstly immobilized on the gold surface. Subsequently, the molecules of Neutravidin were specifically bound to the biotin-terminated self-assembled monolayers (SAMs). The induced changes of cavity length and refractive index (RI) upon the gold surface lead to an optical path difference (OPD) of the FP cavity, which was detected by demodulating the transmission spectrum phase shift. By taking advantage of MEMS techniques, multiple biosensors can be integrated into one small silicon chip for detecting various biomolecule targets simultaneously.

13. GROOVED FOOTING (CONSTRUCTION KEY) EXTENDING ABOVE CEMENT FLOOR IN ...

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

13. GROOVED FOOTING (CONSTRUCTION KEY) EXTENDING ABOVE CEMENT FLOOR IN FIRST UNLINED SECTION BEYOND SOUTH PORTAL. - Salinas River Project, Cuesta Tunnel, Southeast of U.S. 101, San Luis Obispo, San Luis Obispo County, CA

Aluminum U-groove weld enhancement based on experimental stress analyses

NASA Technical Reports Server (NTRS)

Verderaime, V.; Vaughan, R.

1995-01-01

Though butt-welds are among the most preferred joining methods in aerostructures because of their sealing and assembly integrity and general elastic performance; their inelastic mechanics are generally the least understood. This study investigated experimental strain distributions across a thick aluminum U-grooved weld and identified two weld process considerations for improving the multipass weld strength. The extreme thermal expansion and contraction gradient of the fusion heat input across the tab thickness between the grooves produce severe peaking, which induces bending moment under uniaxial loading. The filler strain hardening decreased with increasing filler pass sequence. These combined effects reduce the weld strength, and a depeaking index model was developed to select filler pass thicknesses, pass numbers, and sequences to improve the welding process results over the current normal weld schedule.

Large diameter metal ring seal prevents gas leakage at 5000 psi

NASA Technical Reports Server (NTRS)

Middelkoop, J. H.

1966-01-01

Large metal ring seal prevents gas leakage in hydrogen, helium, or nitrogen storage bottles at pressures up to 5,000 psi. The grooved ring seal which contains elastomer O-rings is installed between the mating faces of the access cover and the storage bottle.

Solution structure of a highly stable DNA duplex conjugated to a minor groove binder.

PubMed Central

Kumar, S; Reed, M W; Gamper, H B; Gorn, V V; Lukhtanov, E A; Foti, M; West, J; Meyer, R B; Schweitzer, B I

1998-01-01

The tripeptide 1,2-dihydro-(3 H )-pyrrolo[3,2- e ]indole-7-carboxylate (CDPI3) binds to the minor groove of DNA with high affinity. When this minor groove binder is conjugated to the 5'-end of short oligonucleotides the conjugates form unusually stable hybrids with complementary DNA and thus may have useful diagnostic and/or therapeutic applications. In order to gain an understanding of the structural interactions between the CDPI3minor groove binding moiety and the DNA, we have determined and compared the solution structure of a duplex consisting of oligodeoxyribonucleotide 5'-TGATTATCTG-3' conjugated at the 5'-end to CDPI3 and its complementary strand to an unmodified control duplex of the same sequence using nuclear magnetic resonance techniques. Thermal denaturation studies indicated that the hybrid of this conjugate with its complementary strand had a melting temperature that was 30 degrees C higher compared with the unmodified control duplex. Following restrained molecular dynamics and relaxation matrix refinement, the solution structure of the CDPI3-conjugated DNA duplex demonstrated that the overall shape of the duplex was that of a straight B-type helix and that the CDPI3moiety was bound snugly in the minor groove, where it was stabilized by extensive van der Waal's interactions. PMID:9443977

Solution structure of a highly stable DNA duplex conjugated to a minor groove binder.

PubMed

Kumar, S; Reed, M W; Gamper, H B; Gorn, V V; Lukhtanov, E A; Foti, M; West, J; Meyer, R B; Schweitzer, B I

1998-02-01

The tripeptide 1,2-dihydro-(3 H )-pyrrolo[3,2- e ]indole-7-carboxylate (CDPI3) binds to the minor groove of DNA with high affinity. When this minor groove binder is conjugated to the 5'-end of short oligonucleotides the conjugates form unusually stable hybrids with complementary DNA and thus may have useful diagnostic and/or therapeutic applications. In order to gain an understanding of the structural interactions between the CDPI3minor groove binding moiety and the DNA, we have determined and compared the solution structure of a duplex consisting of oligodeoxyribonucleotide 5'-TGATTATCTG-3' conjugated at the 5'-end to CDPI3 and its complementary strand to an unmodified control duplex of the same sequence using nuclear magnetic resonance techniques. Thermal denaturation studies indicated that the hybrid of this conjugate with its complementary strand had a melting temperature that was 30 degrees C higher compared with the unmodified control duplex. Following restrained molecular dynamics and relaxation matrix refinement, the solution structure of the CDPI3-conjugated DNA duplex demonstrated that the overall shape of the duplex was that of a straight B-type helix and that the CDPI3moiety was bound snugly in the minor groove, where it was stabilized by extensive van der Waal's interactions.

Cratering and Grooved Terrain on Ganymede

NASA Technical Reports Server (NTRS)

1979-01-01

This color picture as acquired by Voyager 1 during its approach to Ganymede on Monday afternoon (the 5th of March). At ranges between about 230 to 250 thousand km. The image shows detail on the surface with a resolution of four and a half km. This picture is just south of PIA001515 (P21161) and shows more craters. It also shows the two distinctive types of terrain found by Voyager, the darker ungrooved regions and the lighter areas which show the grooves or fractures in abundance. The most striking features are the bright ray craters which havE a distinctly 'bluer' color appearing white against the redder background. Ganymede's surface is known to contain large amounts of surface ice and it appears that these relatively young craters have spread bright fresh ice materials over the surface. Likewise, the lighter color and reflectivity of the grooved areas suggests that here too, there is cleaner ice. We see ray craters with all sizes of ray patterns, ranging from extensive systems of the crater in the northern part of this picture, which has rays at least 300-500 kilometers long, down to craters which have only faint remnants of bright ejecta patterns. This variation suggests that, as on the Moon, there are processes which act to darken ray material, probably 'gardening' by micrometeoroid impact. JPL manages and controls the Voyager project for NASA's Office of Space Science.

The Effectiveness of the "Golfer's Groove" in Improving Golfers' Scores

ERIC Educational Resources Information Center

Yost, Michael; And Others

1976-01-01

Use of the "golfer's groove," a device for controlling the angle and plane of a practicing golfer's swing, significantly influences the accuracy with which male and female college students can be taught to drive golfballs. (MB)

4. DETAIL VIEW OF TRIPLE TONGUE AND GROOVE CRIBBING USED ...

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

4. DETAIL VIEW OF TRIPLE TONGUE AND GROOVE CRIBBING USED IN DAM CONSTRUCTION, NORTH EAST OF EAST DAM, LOOKING NORTH - Three Bears Lake & Dams, East Dam, North of Marias Pass, East Glacier Park, Glacier County, MT

An analytical solution for the squeeze film between a nondeformable sphere and groove

NASA Technical Reports Server (NTRS)

Allen, C. W.; Wilson, M. P.

1972-01-01

An analysis is presented to compute the film thickness, pressure and load relations between a rigid ball and rigid groove in normal approach when lubricated by a fluid with an exponential pressure-viscosity relationship. The geometry of the ball-groove system is reduced to the equivalent system of a paraboloid approaching a flat plate. Exact and approximate solutions are presented for the load and pressure relations. There is found to be a limiting load for a given geometry and lubricant regardless of the rate of approach.

Static Gas-Charging Plug

NASA Technical Reports Server (NTRS)

Indoe, William

2012-01-01

A gas-charging plug can be easily analyzed for random vibration. The design features two steeped O-rings in a radial configuration at two different diameters, with a 0.050-in. (.1.3-mm) diameter through-hole between the two O-rings. In the charging state, the top O-ring is engaged and sealing. The bottom O-ring outer diameter is not squeezed, and allows air to flow by it into the tank. The inner diameter is stretched to plug the gland diameter, and is restrained by the O-ring groove. The charging port bushing provides mechanical stop to restrain the plug during gas charge removal. It also prevents the plug from becoming a projectile when removing gas charge from the accumulator. The plug can easily be verified after installation to ensure leakage requirements are met.

Laser Surface Hardening of Groove Edges

NASA Astrophysics Data System (ADS)

Hussain, A.; Hamdani, A. H.; Akhter, R.; Aslam, M.

2013-06-01

Surface hardening of groove-edges made of 3Cr13 Stainless Steel has been carried out using 500 W CO2 laser with a rectangular beam of 2.5×3 mm2. The processing speed was varied from 150-500 mm/min. It was seen that the hardened depth increases with increase in laser interaction time. A maximum hardened depth of around 1mm was achieved. The microhardness of the transformed zone was 2.5 times the hardness of base metal. The XRD's and microstructural analysis were also reported.

Effects of hierarchical features on longevity of submerged superhydrophobic surfaces with parallel grooves

NASA Astrophysics Data System (ADS)

Hemeda, A. A.; Gad-el-Hak, M.; Tafreshi, H. Vahedi

2014-08-01

While the air-water interface over superhydrophobic surfaces decorated with hierarchical micro- or nanosized geometrical features have shown improved stability under elevated pressures, their underwater longevity—-the time that it takes for the surface to transition to the Wenzel state—-has not been studied. The current work is devised to study the effects of such hierarchical features on the longevity of superhydrophobic surfaces. For the sake of simplicity, our study is limited to superhydrophobic surfaces composed of parallel grooves with side fins. The effects of fins on the critical pressure—-the pressure at which the surface starts transitioning to the Wenzel state—-and longevity are predicted using a mathematical approach based on the balance of forces across the air-water interface. Our results quantitatively demonstrate that the addition of hierarchical fins significantly improves the mechanical stability of the air-water interface, due to the high advancing contact angles that can be achieved when an interface comes in contact with the fins sharp corners. For longevity on the contrary, the hierarchical fins were only effective at hydrostatic pressures below the critical pressure of the original smooth-walled groove. Our results indicate that increasing the length of the fins decreases the critical pressure of a submerged superhydrophobic groove but increases its longevity. Increasing the thickness of the fins can improve both the critical pressure and longevity of a submerged groove. The mathematical framework presented in this paper can be used to custom-design superhydrophobic surfaces for different applications.

Torque scaling in small-gap Taylor-Couette flow with smooth or grooved wall

NASA Astrophysics Data System (ADS)

Zhu, Bihai; Ji, Zengqi; Lou, Zhengkun; Qian, Pengcheng

2018-03-01

The torque in the Taylor-Couette flow for radius ratios η ≥0.97 , with smooth or grooved wall static outer cylinders, is studied experimentally, with the Reynolds number of the inner cylinder reaching up to Rei=2 ×105 , corresponding to the Taylor number up to Ta =5 ×1010 . The grooves are perpendicular to the mean flow, and similar to the structure of a submersible motor stator. It is found that the dimensionless torque G , at a given Rei and η , is significantly greater for grooved cases than smooth cases. We compare our experimental torques for the smooth cases to the fit proposed by Wendt [F. Wendt, Ing.-Arch. 4, 577 (1993), 10.1007/BF02084936] and the fit proposed by Bilgen and Boulos [E. Bilgen and R. Boulos, J Fluids Eng. 95, 122 (1973), 10.1115/1.3446944], which shows both fits are outside their range for small gaps. Furthermore, an additional dimensionless torque (angular velocity flux) N uω in the smooth cases exhibits an effective scaling of N uω˜T a0.39 in the ultimate regime, which occurs at a lower Taylor number, Ta ≈3.5 ×107 , than the well-explored η =0.714 case (at Ta ≈3 ×108 ). The same effective scaling exponent, 0.39, is also evident in the grooved cases, but for η =0.97 and 0.985, there is a peak before this exponent appears.

Effect of groove width of modified current collector on internal short circuit of abused lithium-ion battery

NASA Astrophysics Data System (ADS)

Wang, Meng; Shi, Yang; Noelle, Daniel J.; Le, Anh V.; Qiao, Yu

2017-10-01

In a lithium-ion battery (LIB), mechanical abuse often leads to internal short circuits (ISC) that trigger thermal runaway. We investigated a thermal-runaway mitigation (TRM) technique using a modified current collector. By generating surface grooves on the current collector, the area of electrodes directly involved in ISC could be largely reduced, which decreased the ISC current. The TRM mechanism took effect immediately after the LIB was damaged. The testing data indicate that the groove width is a critical factor. With optimized groove width, this technique may enable robust and multifunctional design of LIB cells for large-scale energy-storage units.

In Vitro Retentive Effect of Groove, Sandblasting, and Cement Type on Stainless Steel Crowns in Primary Molars.

PubMed

Pathak, Sidhant; Shashibhushan, K K; Bharath, K P; Poornima, P; Reddy, V V Subba

2015-01-01

The purpose of this study was to evaluate and compare the effect of placing vertical grooves, sandblasting, and luting cements on the retention of stainless steel crowns (SSCs). Eighty extracted primary molars were mounted in acrylic blocks. Specimens were divided into Group 1 (RelyX U200) and Group 2 (Smart Cem2). Teeth in each group were further subdivided into Subgroup A (no vertical grooves and no sandblasting), Subgroup B (vertical grooves), Subgroup C (sandblasting of crowns), and Subgroup D (vertical grooves and sandblasting of crowns). After cementation, SSCs were pulled off using a universal testing machine. One-way analysis of variance was used for statistical analyses. In Groups 1 and 2, the highest retentive strengths were found in Subgroup D (1,124 and 783 kPa, respectively), followed by Subgroup C (1,066 and 748 kPa, respectively), Subgroup A (762 and 356 kPa, respectively), and Subgroup B (743 and 314 kPa, respectively). Retentive strength in Group one was significantly higher than in Group two; Subgroups A and B were significantly lower than C and D. RelyX U200 showed higher retentive strength than Smart Cem2. Sandblasting increased the retention strength, whereas a vertical groove had no significant effect on retention.

A Gas Lubricant Combined Support-sealing Node

NASA Astrophysics Data System (ADS)

Falaleev, S. V.; Nadjari, H.; Vinogradov, A. S.

2018-01-01

The purpose of the research provided in this article is to develop a gas-dynamic device capable of performing the functions of support sealing, unloading devices for axial thrust bearings and damping of axial vibrations of the rotor. Some kinds of seals applied in supports of aircraft engines are known. A face gas-dynamic seal is one of the most effective and standard technology solution for compressors. As the basic element of the developed device, a face gas-dynamic seal with spiral grooves is considered. It also includes the fundamental mathematical calculation of such devices and the experimental research outcomes that form the basis of which such devices can be produced and adapted for use.

Getting into the GROOVE: How Building Effective Education Partnerships and Promoting Authentic Student Research through the Girls' Remotely Operated Ocean Vehicle Exploration (GROOVE) Workshop.

NASA Astrophysics Data System (ADS)

Pelz, M.; Heesemann, M.; Hoeberechts, M.

2017-12-01

This presentation outlines the pilot year of Girls' Remotely Operated Ocean Vehicle Exploration or GROOVE, a hands-on learning program created collaboratively with education partners Ocean Networks Canada and St. Margaret's School (Victoria, BC, Canada). The program features student-led activities, authentic student experiences, clearly outlined learning outcomes, teacher and student self-assessment tools, and curriculum-aligned content. Presented through the lens of STEM, students build a modified Seaperch ROV and explore and research thematic scientific concepts such as buoyancy, electronic circuitry, and deep-sea exploration. Further, students learn engineering skills such as isotropic scaling, soldering, and assembly as they build their ROV. Ocean Networks Canada (ONC), an initiative of the University of Victoria, develops, operates, and maintains cabled ocean observatory systems. These include technologies developed on the world-leading NEPTUNE and VENUS observatories and the ever-expanding network of community observatories in the Arctic and coastal British Columbia. These observatories, large and small, enable communities, users, scientists, teachers, and students to monitor real-time and historical data from the local marine environment from anywhere on the globe. GROOVE, Girls' Remotely Operated Ocean Vehicle Exploration, is ONC's newest educational program and is related to their foundational program K-12 Ocean Sense educational program. This presentation will share our experiences developing, refining, and assessing our efforts to implement GROOVE using a train-the-trainer model aimed at formal and informal K-12 educators. We will highlight lessons learned from multiple perspectives (students, participants, developers, and mentors) with the intent of informing future education and outreach initiatives.

In and out of the minor groove: interaction of an AT-rich DNA with the drug CD27

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

Acosta-Reyes, Francisco J.; Dardonville, Christophe; Koning, Harry P. de

New features of an antiprotozoal DNA minor-groove binding drug, which acts as a cross-linking agent, are presented. It also fills the minor groove of DNA completely and prevents the access of proteins. These features are also expected for other minor-groove binding drugs when associated with suitable DNA targets. The DNA of several pathogens is very rich in AT base pairs. Typical examples include the malaria parasite Plasmodium falciparum and the causative agents of trichomoniasis and trypanosomiases. This fact has prompted studies of drugs which interact with the minor groove of DNA, some of which are used in medical practice. Previousmore » studies have been performed almost exclusively with the AATT sequence. New features should be uncovered through the study of different DNA sequences. In this paper, the crystal structure of the complex of the DNA duplex d(AAAATTTT){sub 2} with the dicationic drug 4, 4′-bis(imidazolinylamino)diphenylamine (CD27) is presented. The drug binds to the minor groove of DNA as expected, but it shows two new features that have not previously been described: (i) the drugs protrude from the DNA and interact with neighbouring molecules, so that they may act as cross-linking agents, and (ii) the drugs completely cover the whole minor groove of DNA and displace bound water. Thus, they may prevent the access to DNA of proteins such as AT-hook proteins. These features are also expected for other minor-groove binding drugs when associated with all-AT DNA. These findings allow a better understanding of this family of compounds and will help in the development of new, more effective drugs. New data on the biological interaction of CD27 with the causative agent of trichomoniasis, Trichomonas vaginalis, are also reported.« less

Combustor exhaust emissions with air-atomizing splash-groove fuel injectors burning Jet A and Diesel number 2 fuels

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1975-01-01

Air-atomizing, splash-groove injectors were shown to improve primary-zone fuel spreading and reduce combustor exhaust emissions for Jet A and diesel number 2 fuels. With Jet A fuel large-orifice, splash-groove injectors the oxides-of-nitrogen emission index was reduced, but emissions of carbon monoxide, unburned hydrocarbons, or smoke were unaffected. Small-orifice, splash-groove injectors did not reduce oxides of nitrogen, but reduced the smoke number and carbon monoxide and unburned-hydrocarbon emission indices. With diesel number 2 fuel, the small-orifice, splash-groove injectors reduced oxides of nitrogen by 19 percent, smoke number by 28 percent, carbon monoxide by 75 percent, and unburned hydrocarbons by 50 percent. Smoke number and unburned hydrocarbons were twice as high with diesel number 2 as with Jet A fuel. Combustor blowout limits were similar for diesel number 2 and Jet A fuels.

Development of an equine groove model to induce metacarpophalangeal osteoarthritis: a pilot study on 6 horses.

PubMed

Maninchedda, Ugo; Lepage, Olivier M; Gangl, Monika; Hilairet, Sandrine; Remandet, Bernard; Meot, Francoise; Penarier, Geraldine; Segard, Emilie; Cortez, Pierre; Jorgensen, Christian; Steinberg, Régis

2015-01-01

The aim of this work was to develop an equine metacarpophalangeal joint model that induces osteoarthritis that is not primarily mediated by instability or inflammation. The study involved six Standardbred horses. Standardized cartilage surface damage or "grooves" were created arthroscopically on the distal dorsal aspect of the lateral and medial metacarpal condyles of a randomly chosen limb. The contralateral limb was sham operated. After 2 weeks of stall rest, horses were trotted 30 minutes every other day for 8 weeks, then evaluated for lameness and radiographed. Synovial fluid was analyzed for cytology and biomarkers. At 10 weeks post-surgery, horses were euthanized for macroscopic and histologic joint evaluation. Arthroscopic grooving allowed precise and identical damage to the cartilage of all animals. Under the controlled exercise regime, this osteoarthritis groove model displayed significant radiographic, macroscopic, and microscopic degenerative and reactive changes. Histology demonstrated consistent surgically induced grooves limited to non-calcified cartilage and accompanied by secondary adjacent cartilage lesions, chondrocyte necrosis, chondrocyte clusters, cartilage matrix softening, fissuring, mild subchondral bone inflammation, edema, and osteoblastic margination. Synovial fluid biochemistry and cytology demonstrated significantly elevated total protein without an increase in prostaglandin E2, neutrophils, or chondrocytes. This equine metacarpophalangeal groove model demonstrated that standardized non-calcified cartilage damage accompanied by exercise triggered altered osteochondral morphology and cartilage degeneration with minimal or inefficient repair and little inflammatory response. This model, if validated, would allow for assessment of disease processes and the effects of therapy.

Molecular Probing of the HPV-16 E6 Protein Alpha Helix Binding Groove with Small Molecule Inhibitors

PubMed Central

Rietz, Anne; Petrov, Dino P.; Bartolowits, Matthew; DeSmet, Marsha; Davisson, V. Jo; Androphy, Elliot J.

2016-01-01

The human papillomavirus (HPV) HPV E6 protein has emerged as a central oncoprotein in HPV-associated cancers in which sustained expression is required for tumor progression. A majority of the E6 protein interactions within the human proteome use an alpha-helix groove interface for binding. The UBE3A/E6AP HECT domain ubiquitin ligase binds E6 at this helix-groove interface. This enables formation of a trimeric complex with p53, resulting in destruction of this tumor suppressor. While recent x-ray crystal structures are useful, examples of small molecule probes that can modulate protein interactions at this interface are limited. To develop insights useful for potential structure-based design of ligands for HPV E6, a series of 2,6-disubstituted benzopyranones were prepared and tested as competitive antagonists of E6-E6AP helix-groove interactions. These small molecule probes were used in both binding and functional assays to evaluate recognition features of the E6 protein. Evidence for an ionic functional group interaction within the helix groove was implicated by the structure-activity among the highest affinity ligands. The molecular topographies of these protein-ligand interactions were evaluated by comparing the binding and activities of single amino acid E6 mutants with the results of molecular dynamic simulations. A group of arginine residues that form a rim-cap over the E6 helix groove offer compensatory roles in binding and recognition of the small molecule probes. The flexibility and impact on the overall helix-groove shape dictated by these residues offer new insights for structure-based targeting of HPV E6. PMID:26915086

The effect of shoe soling tread groove width on the coefficient of friction with different sole materials, floors, and contaminants.

PubMed

Li, Kai Way; Chen, Chin Jung

2004-11-01

Tread groove design is very common in footwear. However, coefficient of friction (COF) measurements between the footwear material and floor using a slipmeter were commonly performed using flat footwear pads. Such measurements might underestimate the actual slip resistance of the footwear pad. This research investigates the effects of the tread groove width on the measured COF using four footwear materials, three floors, and four liquid-contamination conditions using a Brungraber Mark II slipmeter. The analysis of variance results indicated that the footwear material, floor, contamination conditions, and groove width were all significant (p < 0.0001) factors affecting the measured COF. The hypothesis that wider tread grooves result in higher COF values was true with some exceptions especially on oil contaminated floors. A regression model, with an R2 of 0.91, was established to describe and predict the relationship between the COF and the tread groove width under footwear material/floor/contamination conditions.

Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves

PubMed Central

GOKTURK, Hakan; OZKOCAK, Ismail; BUYUKGEBIZ, Feyzi; DEMIR, Osman

2017-01-01

Abstract Objective The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities. Material and Methods The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal–Wallis and Bonferroni-Correction Mann–Whitney U tests. Results Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05). Conclusions Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves. PMID:28678948

Roughness-Induced Magnetic Domain in Fe Thin Films on Land-and-Groove Structures Studied by Spin-Polarized Secondary Electron Microscopy

NASA Astrophysics Data System (ADS)

Ueda, Shigenori; Iwasaki, Yoh; Ushioda, Sukekatsu

2003-10-01

The magnetic domain structures of Fe thin films on two-dimensionally arranged land-and-groove structures have been studied by spin-polarized secondary electron microscopy (SP-SEM) under an applied dc field. The coercive force on the land area was found to be higher than that on the groove area under magnetization reversal. The surface roughness measured by atomic force microscopy (AFM) was greater on the land area than on the groove area. The roughness-induced high-coercivity on the land prevented the reversed magnetic domain on the groove from spreading over the land in the initial magnetization reversal. This result indicates that surface roughness is an important factor in domain size control of thin magnetic films.

Effectiveness of noise barriers installed adjacent to transverse grooved concrete pavement.

DOT National Transportation Integrated Search

2009-10-16

In recent years the Ohio Department of Transportation (ODOT) has reconstructed a number of roadways where asphalt pavements were replaced with random transverse grooved concrete pavements. Upon completion, residents living adjacent to the reconstruct...

J{sub IC} evaluation of the smooth and the side-grooved CT specimen in the reactor pressure vessel steel (SA508-3)

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

Oh, S.W.; Lim, M.B.; Kim, T.H.

1993-12-31

The elastic-plastic fracture toughness J{sub IC} of SA508-3 forging steel was investigated by using CT-type specimens. The thickness of the smooth specimen is B{sub 0} = 25.4 mm and the side groove specimen is B{sub N} = 20.4 mm and the side groove deep is S{center_dot}G = [(B{sub 0} {minus} B{sub N})/B{sub 0}] {times} 100 = 19.7% and the groove angle is 90{degree}. The J{sub IC} tests estimated according to the method proposed in the ASTM E813-81 and JSME S001-81. The side-grooved specimen have the advantage of J{sub IC} estimation, it is much easier to determine the onset of ductilemore » tearing by the R-curve method and it improved accuracy and scatter of the toughness values thus determined, provided all the size-requirements for the specimen prescribed in the JSME method were satisfied. But it is difficult to find by the ASTM method. The critical stretched zone width (SZW{sub C}) of the side-grooved specimens found to be smaller than that previously determined for the standard CT specimens without side-grooves. This was attributed to higher triaxiality produced by the side-grooves. The stretched zone width method gave slightly larger J{sub IC} values than those by the R-curve method for SA508-3, as has been observed for the standard specimen without side-groove.« less

Influence of structural parameters of deep groove ball bearings on vibration

NASA Astrophysics Data System (ADS)

Yu, Guangwei; Wu, Rui; Xia, Wei

2018-04-01

Taking 6201 bearing as the research object, a dynamic model of 4 degrees of freedom is established to solve the vibration characteristics such as the displacement, velocity and acceleration of deep groove ball bearings by MATLAB and Runge-Kutta method. By calculating the theoretical value of the frequency of the rolling element passing through the outer ring and the simulation value of the model, it can be known that the theoretical calculation value and the simulation value have good consistency. By the experiments, the measured values and simulation values are consistent. Using the mathematical model, the effect of structural parameters on vibration is obtained. The method in the paper is testified to be feasible and the results can be used as references for the design, manufacturing and testing of deep groove ball bearings.

Investigation of accident reduction by grooved concrete pavement : final report.

DOT National Transportation Integrated Search

1979-06-01

This report is a category 2 experimental project evaluation written in conjunction with EHS-I-10-3(93)158 and EHS-I-12-1(44)0 contracted to groove hardened PCC pavement. In it the wear characteristics, pavement texture, skid resistance, and the accid...

9. DETAIL VIEW OF 2' TONGUE AND GROOVE PLANKING IN ...

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

9. DETAIL VIEW OF 2' TONGUE AND GROOVE PLANKING IN WATER CONTROL BOX. THIS SAME PLANKING IS USED AS CRIBBING FOR BOTH EAST DAM AND WEST DAM - Three Bears Lake & Dams, Water Control Box, North of Marias Pass, East Glacier Park, Glacier County, MT

The location of the peroneus longus tendon in the cuboid groove: sonographic study in various positions of the ankle-foot in asymptomatic volunteers.

PubMed

Choo, Hye Jung; Lee, Sun Joo; Huang, Brady K; Resnick, Donald L

2018-04-10

To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers. Ultrasonographic assessment of the PL in the cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle-foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as "inside" when the PL was entirely within the cuboid groove, as "overlying" when some part of the PL was perched on the cuboid tuberosity, and as "outside" when the PL was entirely on the cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the cuboid groove was measured in the neutral position. The PL location did not significantly change with changes in the ankle-foot position. Qualitatively, an "overlying" PL was the most common type, regardless of the ankle-foot position. "Inside" PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle-foot positions and it was significantly negatively correlated with the cuboid groove width. In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle-foot position. The PL location relative to the cuboid groove was related to the cuboid groove width.

Numerical study of the collar wave characteristics and the effects of grooves in acoustic logging while drilling

NASA Astrophysics Data System (ADS)

Yang, Yufeng; Guan, Wei; Hu, Hengshan; Xu, Minqiang

2017-05-01

Large-amplitude collar wave covering formation signals is still a tough problem in acoustic logging-while-drilling (LWD) measurements. In this study, we investigate the propagation and energy radiation characteristics of the monopole collar wave and the effects of grooves on reducing the interference to formation waves by finite-difference calculations. We found that the collar wave radiates significant energy into the formation by comparing the waveforms between a collar within an infinite fluid, and the acoustic LWD in different formations with either an intact or a truncated collar. The collar wave recorded on the outer surface of the collar consists of the outward-radiated energy direct from the collar (direct collar wave) and that reflected back from the borehole wall (reflected collar wave). All these indicate that the significant effects of the borehole-formation structure on collar wave were underestimated in previous studies. From the simulations of acoustic LWD with a grooved collar, we found that grooves broaden the frequency region of low collar-wave excitation and attenuate most of the energy of the interference waves by multireflections. However, grooves extend the duration of the collar wave and convert part of the collar-wave energy originally kept in the collar into long-duration Stoneley wave. Interior grooves are preferable to exterior ones because both the low-frequency and the high-frequency parts of the collar wave can be reduced and the converted inner Stoneley wave is relatively difficult to be recorded on the outer surface of the collar. Deeper grooves weaken the collar wave more greatly, but they result in larger converted Stoneley wave especially for the exterior ones. The interference waves, not only the direct collar wave but also the reflected collar wave and the converted Stoneley waves, should be overall considered for tool design.

Binding to the minor groove of the double-strand, tau protein prevents DNA from damage by peroxidation.

PubMed

Wei, Yan; Qu, Mei-Hua; Wang, Xing-Sheng; Chen, Lan; Wang, Dong-Liang; Liu, Ying; Hua, Qian; He, Rong-Qiao

2008-07-02

Tau, an important microtubule associated protein, has been found to bind to DNA, and to be localized in the nuclei of both neurons and some non-neuronal cells. Here, using electrophoretic mobility shifting assay (EMSA) in the presence of DNA with different chain-lengths, we observed that tau protein favored binding to a 13 bp or a longer polynucleotide. The results from atomic force microscopy also showed that tau protein preferred a 13 bp polynucleotide to a 12 bp or shorter polynucleotide. In a competitive assay, a minor groove binder distamycin A was able to replace the bound tau from the DNA double helix, indicating that tau protein binds to the minor groove. Tau protein was able to protect the double-strand from digestion in the presence of DNase I that was bound to the minor groove. On the other hand, a major groove binder methyl green as a negative competitor exhibited little effect on the retardation of tau-DNA complex in EMSA. This further indicates the DNA minor groove as the binding site for tau protein. EMSA with truncated tau proteins showed that both the proline-rich domain (PRD) and the microtubule-binding domain (MTBD) contributed to the interaction with DNA; that is to say, both PRD and MTBD bound to the minor groove of DNA and bent the double-strand, as observed by electron microscopy. To investigate whether tau protein is able to prevent DNA from the impairment by hydroxyl free radical, the chemiluminescence emitted by the phen-Cu/H(2)O(2)/ascorbate was measured. The emission intensity of the luminescence was markedly decreased when tau protein was present, suggesting a significant protection of DNA from the damage in the presence of hydroxyl free radical.

Source Listings for Computer Code SPIRALI Incompressible, Turbulent Spiral Grooved Cylindrical and Face Seals

NASA Technical Reports Server (NTRS)

Walowit, Jed A.; Shapiro, Wibur

2005-01-01

This is the source listing of the computer code SPIRALI which predicts the performance characteristics of incompressible cylindrical and face seals with or without the inclusion of spiral grooves. Performance characteristics include load capacity (for face seals), leakage flow, power requirements and dynamic characteristics in the form of stiffness, damping and apparent mass coefficients in 4 degrees of freedom for cylindrical seals and 3 degrees of freedom for face seals. These performance characteristics are computed as functions of seal and groove geometry, load or film thickness, running and disturbance speeds, fluid viscosity, and boundary pressures.

Design and performance of compliant thrust bearing with spiral-groove membranes on resilient supports

NASA Technical Reports Server (NTRS)

Licht, L.; Anderson, W. J.; Doroff, S. W.

1980-01-01

Novel thrust bearings with spiral-groove flexible membranes mounted on resilient supports were designed and their performance demonstrated. Advantages of surface compliance were combined with the superior load-capacity of the spiral-groove geometry. Loads of 127-150N were supported on an area 42 sq cm, at speeds of 43,000-45,000 rpm and mean clearances of 15-20 microns. Support-worthiness was proved when tested in conjunction with foil journal-bearings and a 19N rotor, excited in a pitching mode by a total unbalance of 43 micron-N.

Design and experimental study on Fresnel lens of the combination of equal-width and equal-height of grooves

NASA Astrophysics Data System (ADS)

Guo, Limin; Liu, Youqiang; Huang, Rui; Wang, Zhiyong

2017-06-01

High concentrating PV systems rely on large Fresnel lens that must be precisely oriented in the direction of the Sun to maintain high concentration ratio. We propose a new Fresnel lens design method combining equal-width and equal-height of grooves in this paper based on the principle of focused spot maximum energy. In the ring band near the center of Fresnel lens, the design with equal-width grooves is applied, and when the given condition is reached, the design with equal-height grooves is introduced near the edges of the Fresnel lens, which ensures all the lens grooves are planar. In this paper, we establish a Fresnel lens design example model by Solidworks, and simulate it with the software ZEMAX. An experimental test platform is built to test, and the simulation correctness is proved by experiments. Experimental result shows the concentrating efficiency of this example is 69.3%, slightly lower than the simulation result 75.1%.

Large Grooves in the South Polar Layered Deposits: Insights from Spacecraft Data and Terrestrial Analogs

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Herkenhoff, K. E.

2000-01-01

The Martian polar layered deposits (PLD) are probably the best source of information about the recent climate history of Mars, but their origin and the mechanisms of accumulation are still a mystery. The polar layers are sedimentary deposits that most planetary scientists believe are composed of water ice and varying amounts of wind-blown dust, although their composition is poorly constrained. Interpretation of the observed polar stratigraphy in terms of global climate changes is complicated by the significant difference in surface ages between the north and south PLD inferred from crater statistics. The study reported here was undertaken as part of the landing site selection effort for the Mars Polar Lander (MPL) and Deep Space 2 (DS2) missions that made use of all available data. We used Mariner 9, Viking, and Mars Global Surveyor images of the south PLD in the area accessible to MPL and DS2 to evaluate the topography and morphology of grooves, terraced layers, and other features. Here we report on results from grooves that appear to have been carved by strong winds. Because these features are found throughout the interior of the PLD, where MPL and DS2 were targeted to land, their topographic characteristics were judged as important input for landing site safety assessment. The characteristics of the grooves also provide constraints and insights into aeolian processes in the polar regions and the effects these have on PLD ablation. Our results indicate that these grooves do not represent landing hazards at the scale of the images (approx. 80 m/pixel). Their topography and shape do not seem correlated with south PLD layering. No Earth analog of suitable scale exists, although the grooves bear some resemblance to smaller terrestrial deflation hollows found in soft sediment and ice. Additional information is contained in original extended abstract.

A New Method of Administering the Grooved Pegboard Test: Performance as a Function of Handedness and Sex

ERIC Educational Resources Information Center

Bryden, P.J.; Roy, E.A.

2005-01-01

The purpose of the present study was twofold: first to examine the influences of sex and handedness on manual performance on the Grooved Pegboard Test; and secondly to provide normative data for two versions (Place and Remove tasks) of the Grooved Pegboard Test, as previous work (Bryden & Roy, 1999) had suggested that the Remove task of the…

Process Simulation of Gas Metal Arc Welding Software

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

Murray, Paul E.

2005-09-06

ARCWELDER is a Windows-based application that simulates gas metal arc welding (GMAW) of steel and aluminum. The software simulates the welding process in an accurate and efficient manner, provides menu items for process parameter selection, and includes a graphical user interface with the option to animate the process. The user enters the base and electrode material, open circuit voltage, wire diameter, wire feed speed, welding speed, and standoff distance. The program computes the size and shape of a square-groove or V-groove weld in the flat position. The program also computes the current, arc voltage, arc length, electrode extension, transfer ofmore » droplets, heat input, filler metal deposition, base metal dilution, and centerline cooling rate, in English or SI units. The simulation may be used to select welding parameters that lead to desired operation conditions.« less

Is Perceptual Narrowing Too Narrow?

ERIC Educational Resources Information Center

Cashon, Cara H.; Denicola, Christopher A.

2011-01-01

There is a growing list of examples illustrating that infants are transitioning from having earlier abilities that appear more "universal," "broadly tuned," or "unconstrained" to having later abilities that appear more "specialized," "narrowly tuned," or "constrained." Perceptual narrowing, a well-known phenomenon related to face, speech, and…

Disk in a groove with friction: An analysis of static equilibrium and indeterminacy

NASA Astrophysics Data System (ADS)

Donolato, Cesare

2018-05-01

This note studies the statics of a rigid disk placed in a V-shaped groove with frictional walls and subjected to gravity and a torque. The two-dimensional equilibrium problem is formulated in terms of the angles that contact forces form with the normal to the walls. This approach leads to a single trigonometric equation in two variables whose domain is determined by Coulomb's law of friction. The properties of solutions (existence, uniqueness, or indeterminacy) as functions of groove angle, friction coefficient and applied torque are derived by a simple geometric representation. The results modify some of the conclusions by other authors on the same problem.

Aptamer sensor for cocaine using minor groove binder based energy transfer.

PubMed

Zhou, Jinwen; Ellis, Amanda V; Kobus, Hilton; Voelcker, Nicolas H

2012-03-16

We report on an optical aptamer sensor for cocaine detection. The cocaine sensitive fluorescein isothiocyanate (FITC)-labeled aptamer underwent a conformational change from a partial single-stranded DNA with a short hairpin to a double-stranded T-junction in the presence of the target. The DNA minor groove binder Hoechst 33342 selectively bound to the double-stranded T-junction, bringing the dye within the Förster radius of FITC, and therefore initiating minor groove binder based energy transfer (MBET), and reporting on the presence of cocaine. The sensor showed a detection limit of 0.2 μM. The sensor was also implemented on a carboxy-functionalized polydimethylsiloxane (PDMS) surface by covalently immobilizing DNA aptamers. The ability of surface-bound cocaine detection is crucial for the development of microfluidic sensors. Copyright © 2012 Elsevier B.V. All rights reserved.

UTILITY ROOM WITH CANEC PANEL CEILING AND TONGUE AND GROOVE ...

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

UTILITY ROOM WITH CANEC PANEL CEILING AND TONGUE AND GROOVE WALL BOARDS. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Four-Bedroom, Single-Family Type 10, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Synthesis and characterization of DNA minor groove binding alkylating agents.

PubMed

Iyer, Prema; Srinivasan, Ajay; Singh, Sreelekha K; Mascara, Gerard P; Zayitova, Sevara; Sidone, Brian; Fouquerel, Elise; Svilar, David; Sobol, Robert W; Bobola, Michael S; Silber, John R; Gold, Barry

2013-01-18

Derivatives of methyl 3-(1-methyl-5-(1-methyl-5-(propylcarbamoyl)-1H-pyrrol-3-ylcarbamoyl)-1H-pyrrol-3-ylamino)-3-oxopropane-1-sulfonate (1), a peptide-based DNA minor groove binding methylating agent, were synthesized and characterized. In all cases, the N-terminus was appended with an O-methyl sulfonate ester, while the C-terminus group was varied with nonpolar and polar side chains. In addition, the number of pyrrole rings was varied from 2 (dipeptide) to 3 (tripeptide). The ability of the different analogues to efficiently generate N3-methyladenine was demonstrated as was their selectivity for minor groove (N3-methyladenine) versus major groove (N7-methylguanine) methylation. Induced circular dichroism studies were used to measure the DNA equilibrium binding properties of the stable sulfone analogues; the tripeptide binds with affinity that is >10-fold higher than that of the dipeptide. The toxicities of the compounds were evaluated in alkA/tag glycosylase mutant E. coli and in human WT glioma cells and in cells overexpressing and under-expressing N-methylpurine-DNA glycosylase, which excises N3-methyladenine from DNA. The results show that equilibrium binding correlates with the levels of N3-methyladenine produced and cellular toxicity. The toxicity of 1 was inversely related to the expression of MPG in both the bacterial and mammalian cell lines. The enhanced toxicity parallels the reduced activation of PARP and the diminished rate of formation of aldehyde reactive sites observed in the MPG knockdown cells. It is proposed that unrepaired N3-methyladenine is toxic due to its ability to directly block DNA polymerization.

Study of heat transfer due to turbulent flow of nanofluids through rib-groove channel

NASA Astrophysics Data System (ADS)

Al-Shamani, A. N.; Sopian, K.; Abed, A. M.; Alghoul, M. A.; Ruslan, M. H.; Mat, S.

2015-09-01

Nanofluids for improve characteristics flow in a rib-groove channel are investigate. The continuity, momentum and energy equations were solved by FLUENT program. The bottom wall of channel is heated while the upper wall is symmetry, the left side velocity inlet, and the right side is outlet (pressure out). Four different rib-groove shapes are used. Four different types of nanoparticles, Al2O3, CuO, SiO2, and ZnO with different volumes fractions in the range of 1% to 4% and different nanoparticle diameter in the range of 25 nm to 70 nm, are dispersed in the base fluid water are used. In this paper, several parameters such as different Reynolds numbers in the range of 10000 < Re < 40000 are investigated. The numerical results indicate that the trapezoidal with increasing height in the flow direction rib- trapezoidal groove has the best heat transfer and high Nusselt number; the nanofluids with SiO2 have the best behavior. The Nusselt number increases as the volume fraction increases and it decreases as the nanoparticle diameter increases.

Analysis of focusing error signals by differential astigmatic method under off-center tracking in the land-groove-type optical disk

NASA Astrophysics Data System (ADS)

Shinoda, Masahisa; Nakatani, Hidehiko

2015-04-01

We theoretically calculate the behavior of the focusing error signal in the land-groove-type optical disk when the objective lens traverses on out of the radius of the optical disk. The differential astigmatic method is employed instead of the conventional astigmatic method for generating the focusing error signals. The signal behaviors are compared and analyzed in terms of the gain difference of the slope sensitivity of the focusing error signals from the land and the groove. In our calculation, the format of digital versatile disc-random access memory (DVD-RAM) is adopted as the land-groove-type optical disk model, and advantageous conditions for suppressing the gain difference are investigated. The calculation method and results described in this paper will be reflected in the next generation land-groove-type optical disks.

EUV efficiency of a 6000-grooves per mm diffraction grating

NASA Technical Reports Server (NTRS)

Hurwitz, Mark; Bowyer, Stuart; Edelstein, Jerry; Harada, Tatsuo; Kita, Toshiaki

1990-01-01

In order to explore whether grooves ruled mechanically at a density of 6000 per mm can perform well at EUV wavelengths, a sample grating is measured with this density in an EUV calibration facility. Measurements are presented of the planar uniform line-space diffraction grating's efficiency and large-angle scattering.

Bushing retention system for thermal medium cooling delivery tubes in a gas turbine rotor

DOEpatents

Mashey, Thomas Charles

2002-01-01

Bushings are provided in counterbores for wheels and spacers for supporting thermal medium cooling tubes extending axially adjacent the rim of the gas turbine rotor. The retention system includes a retaining ring disposed in a groove adjacent an end face of the bushing and which retaining ring projects radially inwardly to prevent axial movement of the bushing in one direction. The retention ring has a plurality of circumferentially spaced tabs along its inner diameter whereby the ring is supported by the lands of the tube maintaining its bushing retention function, notwithstanding operation in high centrifugal fields and rotation of the ring in the groove into other circular orientations.

Experimental evaluation of two premixing-prevaporizing fuel injection concepts for a gas turbine catalytic combustor

NASA Technical Reports Server (NTRS)

Tacina, R.

1976-01-01

A premixing-prevaporizing fuel system to be used with a catalytic combustor was evaluated for possible application in an automotive gas turbine. Spatial fuel distribution and degree of vaporization were measured using jet A fuel. Two types of air blast injectors were tested, a splash groove injector and a multiple jet cross stream injector. Air swirlers with vane angles of 15 deg and 30 deg were used to improve the spatial fuel distribution in a 12 cm diameter tubular rig. Distribution and vaporization measurements were made 35.5 cm downstream of the injector. The spatial fuel distribution was nearly uniform with the multiple jet contrastream injector and the splash-groove injector with a 30 deg air swirler. The vaporization was nearly 100 percent at an inlet air temperature of 600 K, and at 800 K inlet air temperature fuel oxidation reactions were observed. The total pressure loss was less than 0.5 percent of the total pressure for the multiple jet cross stream injector and the splash groove injector (without air swirler) and less than 1 percent for the splash groove with a 30 deg air swirler.

A study of narrow gap laser welding for thick plates using the multi-layer and multi-pass method

NASA Astrophysics Data System (ADS)

Li, Ruoyang; Wang, Tianjiao; Wang, Chunming; Yan, Fei; Shao, Xinyu; Hu, Xiyuan; Li, Jianmin

2014-12-01

This paper details a new method that combines laser autogenous welding, laser wire filling welding and hybrid laser-GMAW welding to weld 30 mm thick plate using a multi-layer, multi-pass process. A “Y” shaped groove was used to create the joint. Research was also performed to optimize the groove size and the processing parameters. Laser autogenous welding is first used to create the backing weld. The lower, narrowest part of the groove is then welded using laser wire filling welding. Finally, the upper part of the groove is welded using laser-GMAW hybrid welding. Additionally, the wire feeding and droplet transfer behaviors are observed by high speed photography. The two main conclusions from this work are: the wire is often biased towards the side walls, resulting in a lack of fusion at the joint and the creation of other defects for larger groove sizes. Additionally, this results in the droplet transfer behavior becoming unstable, leading to a poor weld appearance for smaller groove sizes.

Extreme gaseous outflows in radio-loud narrow-line Seyfert 1 galaxies

NASA Astrophysics Data System (ADS)

Komossa, S.; Xu, D. W.; Wagner, A. Y.

2018-07-01

We present four radio-loud narrow-line Seyfert 1 (NLS1) galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km s-1, above the escape velocity of the host galaxies. The forbidden lines show strong broadening, up to 2270 km s-1. An ionization stratification (higher line shift at higher ionization potential) implies that we see a large-scale outflow rather than single, localized jet-cloud interactions. Similarly, the paucity of zero-velocity [O III] λ5007 emitting gas implies the absence of a second narrow-line region (NLR) component at rest, and therefore a large part of the high-ionization NLR is affected by the outflow. Given the radio loudness of these NLS1 galaxies, the observations are consistent with a pole on view onto their central engines, so that the effects of polar outflows are maximized. In addition, a very efficient driving mechanism is required to reach the high observed velocities. We explore implications from recent hydrodynamic simulations of the interaction between fast winds or jets with the large-scale NLR. Overall, the best agreement with observations (and especially the high outflow speeds of the [Ne V] emitting gas) can be reached if the NLS1 galaxies are relatively young sources with lifetimes not much exceeding 1 Myr. These systems represent sites of strong feedback at NLR scales at work, well below redshift one.

Regenerated collagen fibers with grooved surface texture: Physicochemical characterization and cytocompatibility.

PubMed

Wang, Xiang; Wu, Tong; Wang, Wei; Huang, Chen; Jin, Xiangyu

2016-01-01

A novel type of protein fibers, regenerated collagen fibers (RC) from cattle skin, was prepared through wet-spinning. Due to the combined effect of solvent exchange and subsequent drawing process, the fibers were found to have a grooved surface texture. The grooves provided not only ordered topographical cues, but also increased surface area. Protein content of the RC fibers was confirmed by Fourier Transform infrared spectroscopy (FTIR) and ninhydrin color reaction. The fibers could be readily fabricated into nonwovens or other textiles, owning to their comparable physical properties to other commercialized fibers. Cell growth behavior on RC nonwovens suggested both early adhesion and prompt proliferation. The high moisture regain, good processability, along with the excellent cytocompatibility indicated that the RC fibers and nonwovens developed in this study might offer a good candidate for biomedical and healthcare applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Biological Glue Application in Repair of Atrioventricular Groove Rupture: A Case Report

PubMed Central

Durukan, Ahmet Baris; Serter, Fatih Tanzer; Gurbuz, Hasan Alper; Tavlasoglu, Murat; Ucar, Halil Ibrahim; Yorgancioglu, Cem

2014-01-01

Abstract Atrioventricular groove rupture is a rare, albeit mortal, complication following mitral valve surgery. Avoidance is the best strategy but it cannot fully prevent the occurrence of this complication. Several repair techniques have been described with varying success rates; however, the rarity of the complication precludes consensus about the safest technique. Here we report two cases of posterior atrioventricular groove rupture. Both cases were diagnosed immediately after the cessation of cardiopulmonary bypass. Repair was performed successfully with a technique involving the use of biological glue. The postoperative course was uneventful for both of them. Both cases are well with normally functioning mitral prostheses; one with a follow-up time of 5.5 years and the other 10 months. We believe that the glue provides additional hemostasis and support to the repaired area. PMID:25870633

Electrified Flow in Slender V-Groove Microchannels: Generalized Stability of Steady State Configurations

NASA Astrophysics Data System (ADS)

Markeviciute, Vilda; White, Nicholas; Troian, Sandra

2017-11-01

Although spontaneous capillary flow can be an especially rapid process in slender open microchannels resembling V-grooves, enhanced flow control is possible through implementation of electric field distributions which generate opposing electrohydrodynamic pressures along the air/liquid interface to modulate the capillary pressures. Important fundamental work by Romero and Yost (1996) and Weislogel(1996) has elucidated the behavior of Newtonian films in slender V-grooves driven to flow solely by the streamwise change in capillary pressure due to the change in radius of curvature of the circular arc describing the interface of wetting or non-wetting fluids. Here we augment the Romero and Yost model with inclusion of Maxwell stresses for perfectly conducting wetting films and examine which electric field distributions allow formation of steady state film shapes for various inlet and outlet boundary conditions. We investigate the stability of these steady solutions to small perturbations in film thickness using a generalized stability analysis. These results reveal how the ratio of Maxwell to capillary stresses influences the degree of linearized transient growth or decay for thin films confined to flow within an open V-groove. Funding from the 2017 Caltech Summer Undergraduate Research Fellowship Program (Markeviciute) as well as a 2017 NASA Space Technology Research Fellowship (White) is gratefully acknowledged.

Opposed-Flow Flame Spread over Thin Solid Fuels in a Narrow Channel under Different Gravity

NASA Astrophysics Data System (ADS)

Zhang, Xia; Yu, Yong; Wan, Shixin; Wei, Minggang; Hu, Wen-Rui

Flame spread over solid surface is critical in combustion science due to its importance in fire safety in both ground and manned spacecraft. Eliminating potential fuels from materials is the basic method to protect spacecraft from fire. The criterion of material screening is its flamma-bility [1]. Since gas flow speed has strong effect on flame spread, the combustion behaviors of materials in normal and microgravity will be different due to their different natural convec-tion. To evaluate the flammability of materials used in the manned spacecraft, tests should be performed under microgravity. Nevertheless, the cost is high, so apparatus to simulate mi-crogravity combustion under normal gravity was developed. The narrow channel is such an apparatus in which the buoyant flow is restricted effectively [2, 3]. The experimental results of the horizontal narrow channel are consistent qualitatively with those of Mir Space Station. Quantitatively, there still are obvious differences. However, the effect of the channel size on flame spread has only attracted little attention, in which concurrent-flow flame spread over thin solid in microgravity is numerically studied[4], while the similarity of flame spread in different gravity is still an open question. In addition, the flame spread experiments under microgravity are generally carried out in large wind tunnels without considering the effects of the tunnel size [5]. Actually, the materials are always used in finite space. Therefore, the flammability given by experiments using large wind tunnels will not correctly predict the flammability of materials in the real environment. In the present paper, the effect of the channel size on opposed-flow flame spread over thin solid fuels in both normal and microgravity was investigated and compared. In the horizontal narrow channel, the flame spread rate increased before decreased as forced flow speed increased. In low speed gas flows, flame spread appeared the same trend as that in

The suppression effect of a periodic surface with semicircular grooves on the high power microwave long pill-box window multipactor phenomenon

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

Zhang, Xue, E-mail: zhangxue.iecas@yahoo.com; Wang, Yong; Fan, Junjie

2014-09-15

To improve the transmitting power in an S-band klystron, a long pill-box window that has a disk with grooves with a semicircular cross section is theoretically investigated and simulated. A Monte-Carlo algorithm is used to track the secondary electron trajectories and analyze the multipactor scenario in the long pill-box window and on the grooved surface. Extending the height of the long-box window can decrease the normal electric field on the surface of the window disk, but the single surface multipactor still exists. It is confirmed that the window disk with periodic semicircular grooves can explicitly suppress the multipactor and predominantlymore » depresses the local field enhancement and the bottom continuous multipactor. The difference between semicircular and sharp boundary grooves is clarified numerically and analytically.« less

The suppression effect of a periodic surface with semicircular grooves on the high power microwave long pill-box window multipactor phenomenon

NASA Astrophysics Data System (ADS)

Zhang, Xue; Wang, Yong; Fan, Junjie; Zhong, Yong; Zhang, Rui

2014-09-01

To improve the transmitting power in an S-band klystron, a long pill-box window that has a disk with grooves with a semicircular cross section is theoretically investigated and simulated. A Monte-Carlo algorithm is used to track the secondary electron trajectories and analyze the multipactor scenario in the long pill-box window and on the grooved surface. Extending the height of the long-box window can decrease the normal electric field on the surface of the window disk, but the single surface multipactor still exists. It is confirmed that the window disk with periodic semicircular grooves can explicitly suppress the multipactor and predominantly depresses the local field enhancement and the bottom continuous multipactor. The difference between semicircular and sharp boundary grooves is clarified numerically and analytically.

Comparative Investigation and Operational Performance Characteristics of a Wick Assisted and Axially Square Grooved Heat Pipe

NASA Astrophysics Data System (ADS)

Naik, Rudra, Dr.; Rama Narasihma, K., Dr.; Anikivi, Atmanand

2018-04-01

The present work reported here involves the experimental investigation and performance evaluation of wick assisted and axially square grooved heat pipes of outer diameter 8mm, inner diameter 4mm with a length of 150mm.The objective of this work is to design, fabricate and test the heat pipes with and without an axial square groove for horizontal and gravity assisted conditions. The performance of the heat pipes was measured in terms of thermal resistance and heat transfer coefficients. In the present investigation four different working fluids were chosen namely acetone, ethanol, methanol and distilled water. Experiments were conducted by varying the heat load from 2 W to 10 W for different fill charge ratios in the range of 25% to 75% of evaporator volume for wick assisted heat pipe and 8 W to 18 W for axially square grooved heat pipe. From the experiments, it was found that there is a steady increase in temperature with the increase in heat input. The overall heat transfer coefficient was found to increase with the increase heat load for wick assisted heat pipe. In case of axially square grooved heat pipe, an attempt was made to experiment the heat pipe in different orientations. The maximum heat transfer coefficient of 7000 W/m2 °C is found for Acetone at 180° orientation.

In-Roll Stress Analysis Considering Air-Entrainment at the Roll-Inlet with the Effect of Grooves on Nip Roll Surface

NASA Astrophysics Data System (ADS)

Sasaki, Masashi; Tanimoto, Koshi; Kohno, Kazukiyo; Takahashi, Sadamu; Kometani, Hideo; Hashimoto, Hiromu

High-speed winding of paper web sometimes leads the winding system into unstable states, interlayer slippage of wound roll, paper breakage and so on, due to the excessive air-entrainment at the roll-inlet of nip contact region. These phenomena are more frequently observed on coated paper or plastic film comparing with newspaper, because the former allows little permeation of air and their surface roughness is small. Therefore, it is of vital importance to clarify the in-roll stress of wound roll considering the effect of air-entrainment. Generally, it is known that the amount of air-entrainment is affected by grooving shape of nip roll surface. In this paper, we focused on the grooving shape and investigated the relationship with the air-entrainment into two rolls being pressed each other and the grooving shape in order to achieve stable winding at high speed. We conducted experiments using small sized test machine. Entrained air-film thickness was evaluated applying the solution of the elasto-hydrodynamic lubrication for foil bearing with the consideration of nip profile at the grooved area. Air film thickness was measured to ensure the applicability of the above theory. Consequently, we found that the air film thickness can be estimated considering the effect of grooves on the nip roll surface, and that the validity of the above estimations was ensured from experimental investigations. Furthermore, it became to be able to propose the optimal shape of grooves on nip roll surface to maintain the stable winding at high speed and at large-diameter in reel.

Intercalation and de-intercalation pathway of proflavine through the minor and major grooves of DNA: roles of water and entropy.

PubMed

Sasikala, Wilbee D; Mukherjee, Arnab

2013-05-07

DNA intercalation is a clinically relevant biophysical process due to its potential to inhibit the growth and survival of tumor cells and microbes through the arrest of the transcription and replication processes. Extensive kinetic and thermodynamic studies have followed since the discovery of the intercalative binding mode. However, the molecular mechanism and the origin of the thermodynamic and kinetic profile of the process are still not clear. Here we have constructed the free energy landscape of intercalation, de-intercalation and dissociation from both the major and minor grooves of DNA using extensive all-atom metadynamics simulations, capturing both the free energy barriers and stability in close agreement with fluorescence kinetic experiments. In the intercalated state, an alternate orientation of proflavine is found with an almost equal stability compared to the crystal orientation, however, separated by a 5.0 kcal mol(-1) barrier that decreases as the drug approaches the groove edges. This study provides a comprehensive picture in comparison with experiments, which indicates that the intercalation and de-intercalation of proflavine happen through the major groove side, although the effective intercalation barrier increases because the path of intercalation goes through the stable (abortive) minor groove bound state, making the process a millisecond long one in excellent agreement with the experiments. The molecular origin of the higher barrier for the intercalation from the minor groove side is attributed to the desolvation energy of DNA and the loss of entropy, while the barrier from the major groove, in the absence of desolvation energy, is primarily entropic.

[Lymphogranuloma venereum: new serovariant L2b and old "groove sign"].

PubMed

de Lavaissière, M; Nougué, J

2013-08-01

An ongoing lymphogranuloma venereum (LGV) outbreak has been reported in several European countries since 2003, related to a new variant L2b. This serovar appears to affect men who have sex with men (MSM), most of them being co-infected with the Human Immunodeficiency Virus (HIV). The secondary stage of LGV may involve lymph nodes and the inguinal form has sometimes been described on each side of the inguinal ligament thus named the "groove sign". We report the case of LGV serovariant L2b acquired by an heterosexual intercourse in an HIV seronegative patient who presented with an inguinal lymph node and a "groove sign". This is an uncommon but suggestive sign of LGV and we suggest that the clinical presentation of L2b LGV might not be so different than other variants and than the 20th century authors' description. Such a new Chlamydia trachomatis variant may circulate in other populations than MSM in Europe and clinical awareness must prevail.

RNA major groove modifications improve siRNA stability and biological activity

PubMed Central

Terrazas, Montserrat; Kool, Eric T.

2009-01-01

RNA 5-methyl and 5-propynyl pyrimidine analogs were substituted into short interfering RNAs (siRNAs) to probe major groove steric effects in the active RNA-induced silencing complex (RISC). Synthetic RNA guide strands containing varied combinations of propynyl and methyl substitution revealed that all C-5 substitutions increased the thermal stability of siRNA duplexes containing them. Cellular gene suppression experiments using luciferase targets in HeLa cells showed that the bulky 5-propynyl modification was detrimental to RNA interference activity, despite its stabilization of the helix. Detrimental effects of this substitution were greatest at the 5′-half of the guide strand, suggesting close steric approach of proteins in the RISC complex with that end of the siRNA/mRNA duplex. However, substitutions with the smaller 5-methyl group resulted in gene silencing activities comparable to or better than that of wild-type siRNA. The major groove modifications also increased the serum stability of siRNAs. PMID:19042976

Theoretical approach to obtaining dynamic characteristics of noncontacting spiral-grooved seals

NASA Technical Reports Server (NTRS)

Iwatsubo, Takuzo; Yang, Bo-Suk; Ibaraki, Ryuji

1987-01-01

The dynamic characteristics of spiral-grooved seals are theoretically obtained by using the Navier-Stokes equation. First, with the inertia term of the fluid considered, the flow and pressure in the steady state are obtained for the directions parallel to and perpendicular to the groove. Next, the dynamic character is obtained by analyzing the steady state and by analyzing the labyrinth seal. As a result, the following conclusions were drawn: (1) As the land width becomes shorter or the helix angle decreases, the cross-coupling stiffness, direct and cross-coupling damping, and add mass coefficients decrease; (2) As the axial Reynolds number increases, the stiffness and damping coefficients increase. But the add mass coefficient is not influenced by the axial Reynolds number; (3) The rotational Reynolds number influences greatly the direct and cross-coupling stiffness and direct damping coefficients; and (4) As the journal rotating frequency increases, the leakage flow decreases. Therefore zero net leakage flow is possible at a particular rotating frequency.

Influence of groove size and reinforcements addition on mechanical properties and microstructure of friction stir welded joints

NASA Astrophysics Data System (ADS)

Reddy Baridula, Ravinder; Ibrahim, Abdullah Bin; Yahya, Che Ku Mohammad Faizal Bin Che Ku; Kulkarni, Ratnakar; Varma Ramaraju, Ramgopal

2018-03-01

The butt joints fabricated by friction stir welding were found to have more strength than the joints obtained by conventional joining process. The important outcome of this process is the successful fabrication of surface composites with improved properties. Thus in order to further enhance the strength of the dissimilar alloy joints the reinforcements can be deposited in to the aluminium matrix during the process of friction stir welding. In the present study the multi-walled carbon nanotubes were embedded in to the groove by varying the width during joining of dissimilar alloys AA2024 and AA7075. Four widths were selected with constant depth and optimum process parameters were selected to fabricate the sound welded joints. The results show that the mechanical properties of the fabricated butt joints were influenced by the size of the groove, due to variation in the deposition of reinforcement in the stir zone. The microstructural study and identification of the elements of the welded joints show that the reinforcements deposition is influenced by the size of the groove. It has also been observed that the groove with minimum width is more effective than higher width. The mechanical properties are found to be improved due to the pinning of grain boundaries.

Scary gas: intravascular, intracranial, and intraspinal ectopic gas (part III).

PubMed

Sandstrom, Claire K; Osman, Sherif F; Linnau, Ken F

2017-08-01

While ectopic gas can be a sign of dangerous disease requiring immediate medical or surgical intervention, it can also be an incidental and benign finding. Intravenous gas and spinal vacuum gas are common and almost always benign. Intravascular gas is most often related to instrumentation and, if intraarticular, can cause end-organ ischemia; however, treatment is usually supportive. Pneumocephalus arises from a communication with paranasal sinuses or mastoids more often than from meningeal infection and can usually be managed nonoperatively. In part 3 of this series, the different causes of ectopic gas in the vessels, skull, and spine are reviewed, as are the imaging features that can help to narrow the differential diagnosis.

Fibroblast adhesion and activation onto micro-machined titanium surfaces.

PubMed

Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

2013-07-01

Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (<50 μm) at later stages. The use of micro-grooved surfaces could improve implant integration at the gingival site with respect to polished surfaces. Micro-grooved surfaces enhance early fibroblast adhesion and activation, which could be critical for the formation of a biological seal and finally promote tissue integration. Surfaces with wider

Are Narrow Line Seyfert 1 Galaxies Viewed Pole-on?

DTIC Science & Technology

2011-04-01

0.2’’ respectively. Figure 1 displays the position of each slit over a Barbosa et al. (2009) GMOS IFU image of the [S III] flux (which originates...C. Winge, H. Schmitt: Gemini/ GMOS IFU gas velocity ’tomography’ of the narrow line region of nearby active galaxies, MNRAS, 396 (2009) 2. [2] D...1995) 81. 4 P o S ( N L S 1 ) 0 5 0 Are NLS1s Pole-on? Travis C. Fischer 5 Figure 1: NGC 4051 GMOS IFU image showing integrated [SIII] flux

Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

NASA Astrophysics Data System (ADS)

Akyildiz, Oncu; Omer Ogurtani, Tarik

2011-08-01

The morphological evolution kinetics of a bicrystal thin film induced by anisotropic surface drift diffusion and driven by the applied electrostatic field is investigated via self consistent dynamical computer simulations. The physico-mathematical model, which is based upon the irreversible thermodynamic treatment of surfaces and interfaces with singularities [T. O. Ogurtani, J. Chem. Phys. 124, 144706 (2006)], provided us with auto-control on the otherwise free-motion of the triple junction at the intersection of the grooving surface and the grain boundary, without having any a priori assumption on the equilibrium dihedral angles. The destruction of the symmetry of the freshly formed grain boundary grooves under the anisotropic surface diffusion driven by the concurrent action of the capillarity and electromigration is observed. After prolonged exposure times the applied electric field above the well defined threshold level modifies Mullins' familiar stationary state time law as, t¯1/4, and causes the premature termination of the groove penetration because of the current crowding at the tips of counteracting grain boundary-grooves initiated on both sides of the test modulus. That finding indicates that the electromigration plays the same role as a healing agent [T. O. Ogurtani, J. Appl. Phys. 106, 053503 (2009)] in arresting the thermal grooving, thereby avoiding the premature interconnect failure as in the case of surface roughening and crack initiation caused by compressive stress gradients. The role of the electromigration and wetting parameter on the ridge/slit formations are thoroughly investigated in this study and the prerequisite conditions are also identified.

Olfactory groove meningiomas: approaches and complications.

PubMed

Aguiar, Paulo Henrique Pires de; Tahara, Adriana; Almeida, Antonio Nogueira; Simm, Renata; Silva, Arnaldo Neves da; Maldaun, Marcos Vinicius Calfatt; Panagopoulos, Alexandros Theodoros; Zicarelli, Carlos Alexandre; Silva, Pedro Gabriel

2009-09-01

Olfactory groove meningiomas (OGM) account for 4.5% of all intracranial meningiomas. We report 21 patients with OGMs. Tumors were operated on using three surgical approaches: bifrontal (7 patients), fronto-pterional (11 patients) and fronto-orbital (3 patients). Total tumor removal (Simpson Grade 1) was achieved in 13 patients and Simpson II in 8 patients. Perioperative mortality was 4.76%. The average size of the OGM was 4.3+/-1.1cm. The overall recurrence rate was 19%. We preferred to use the pterional approach, which provides quick access to the tumor with less brain exposure. It also allows complete drainage of cisternal cerebrospinal fluid, providing a good level of brain relaxation during surgery. However, for long, thin tumors, hemostasis can be difficult using this approach.

DETAILED VIEW OF THE CARPORT WITH TWO TONGUE AND GROOVE ...

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

DETAILED VIEW OF THE CARPORT WITH TWO TONGUE AND GROOVE DOORS TO THE STORAGE CLOSET. REPLACEMENT VINYL VENTED SOFFIT MATERIAL IS VISIBLE IN THIS SHOT - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Maintenance free gas bearing helium blower for nuclear plant

NASA Astrophysics Data System (ADS)

Molyneaux, A., Dr; Harris, M., Prof; Sharkh, S., Prof; Hill, S.; de Graaff, T.

2017-08-01

This paper describes the design, testing and operation of novel helium blowers used to recirculate the helium blanketing gas in the nuclear reactor used as a neutron source at the Institut Laue Langevan, Grenoble, France. The laser sintered shrouded centrifugal wheel operates at speeds up to 45000 rpm supported on helium lubricated hydrodynamic spiral groove bearings, and is driven by a sensorless permanent magnet motor. The entire machine is designed to keep the helium gas (polluted by a small amount of D2O) out of contact with any iron or copper materials which would contribute to the corrosion of parts of the circuit. It is designed to have zero maintenance during a lifetime of 40,000 hours of continuous operation. This paper will describe the spiral groove journal and thrust bearings. Design and manufacture of the 1 kW motor and centrifugal wheel will be explained including their CFD and FEA analyses. Measurements of rotor displacement will be presented showing the behaviour under factory testing as well as details of the measured centrifugal wheel and motor performances. Two machines are incorporated into the circuit to provide redundancy and the first blower has been in continuous operation since Jan 2015. The blower was designed, manufactured, assembled and tested in the UK using predominantly UK suppliers.

Development of an Equine Groove Model to Induce Metacarpophalangeal Osteoarthritis: A Pilot Study on 6 Horses

PubMed Central

Maninchedda, Ugo; Lepage, Olivier M.; Gangl, Monika; Hilairet, Sandrine; Remandet, Bernard; Meot, Francoise; Penarier, Geraldine; Segard, Emilie; Cortez, Pierre; Jorgensen, Christian; Steinberg, Régis

2015-01-01

The aim of this work was to develop an equine metacarpophalangeal joint model that induces osteoarthritis that is not primarily mediated by instability or inflammation. The study involved six Standardbred horses. Standardized cartilage surface damage or “grooves” were created arthroscopically on the distal dorsal aspect of the lateral and medial metacarpal condyles of a randomly chosen limb. The contralateral limb was sham operated. After 2 weeks of stall rest, horses were trotted 30 minutes every other day for 8 weeks, then evaluated for lameness and radiographed. Synovial fluid was analyzed for cytology and biomarkers. At 10 weeks post-surgery, horses were euthanized for macroscopic and histologic joint evaluation. Arthroscopic grooving allowed precise and identical damage to the cartilage of all animals. Under the controlled exercise regime, this osteoarthritis groove model displayed significant radiographic, macroscopic, and microscopic degenerative and reactive changes. Histology demonstrated consistent surgically induced grooves limited to non-calcified cartilage and accompanied by secondary adjacent cartilage lesions, chondrocyte necrosis, chondrocyte clusters, cartilage matrix softening, fissuring, mild subchondral bone inflammation, edema, and osteoblastic margination. Synovial fluid biochemistry and cytology demonstrated significantly elevated total protein without an increase in prostaglandin E2, neutrophils, or chondrocytes. This equine metacarpophalangeal groove model demonstrated that standardized non-calcified cartilage damage accompanied by exercise triggered altered osteochondral morphology and cartilage degeneration with minimal or inefficient repair and little inflammatory response. This model, if validated, would allow for assessment of disease processes and the effects of therapy. PMID:25680102

A monofunctional platinum complex coordinated to a rhodium metalloinsertor selectively binds mismatched DNA in the minor groove.

PubMed

Weidmann, Alyson G; Barton, Jacqueline K

2015-10-05

We report the synthesis and characterization of a bimetallic complex derived from a new family of potent and selective metalloinsertors containing an unusual Rh-O axial coordination. This complex incorporates a monofunctional platinum center containing only one labile site for coordination to DNA, rather than two, and coordinates DNA nonclassically through adduct formation in the minor groove. This conjugate displays bifunctional, interdependent binding of mismatched DNA via metalloinsertion at a mismatch as well as covalent platinum binding. DNA sequencing experiments revealed that the preferred site of platinum coordination is not the traditional N7-guanine site in the major groove, but rather N3-adenine in the minor groove. The complex also displays enhanced cytotoxicity in mismatch repair-deficient and mismatch repair-proficient human colorectal carcinoma cell lines compared to the chemotherapeutic cisplatin, and it triggers cell death via an apoptotic pathway, rather than the necrotic pathway induced by rhodium metalloinsertors.

Determinig the Shape Coefficient A of Groove on the Pen for the Shaft

NASA Astrophysics Data System (ADS)

Křístek, Ivo; Havlík, Jiří; Mosler, Václav; Daniš, Igor

2017-12-01

This article focuses on creating a diagram for determining the shape coefficient α for a tongue groove on the shaft. Experimental determination of curve diagrams by comparing diagrams and monograms used using FEM calculations.

Presentation of computer code SPIRALI for incompressible, turbulent, plane and spiral grooved cylindrical and face seals

NASA Technical Reports Server (NTRS)

Walowit, Jed A.

1994-01-01

A viewgraph presentation is made showing the capabilities of the computer code SPIRALI. Overall capabilities of SPIRALI include: computes rotor dynamic coefficients, flow, and power loss for cylindrical and face seals; treats turbulent, laminar, Couette, and Poiseuille dominated flows; fluid inertia effects are included; rotor dynamic coefficients in three (face) or four (cylindrical) degrees of freedom; includes effects of spiral grooves; user definable transverse film geometry including circular steps and grooves; independent user definable friction factor models for rotor and stator; and user definable loss coefficients for sudden expansions and contractions.

Self-consistent simulation of radio frequency multipactor on micro-grooved dielectric surface

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

Cai, Libing; Wang, Jianguo, E-mail: wanguiuc@mail.xjtu.edu.cn; Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024

2015-02-07

The multipactor plays a key role in the surface breakdown on the feed dielectric window irradiated by high power microwave. To study the suppression of multipactor, a 2D electrostatic PIC-MCC simulation code was developed. The space charge field, including surface deposited charge and multipactor electron charge field, is obtained by solving 2D Poisson's equation in time. Therefore, the simulation is self-consistent and does not require presetting a fixed space charge field. By using this code, the self-consistent simulation of the RF multipactor on the periodic micro-grooved dielectric surface is realized. The 2D space distributions of the multipactor electrons and spacemore » charge field are presented. From the simulation results, it can be found that only half slopes have multipactor discharge when the slope angle exceeds a certain value, and the groove presents a pronounced suppression effect on the multipactor.« less

Vertically aligned gas-insulated transmission line having particle traps at the inner conductor

DOEpatents

Dale, Steinar J.

1984-01-01

Gas insulated electrical apparatus having first and second conductors separated by an insulating support within an insulating gas environment, and particle traps disposed along the surface of the high potential conductor for trapping and inactivating foreign particles which may be present within the insulating gas medium. Several embodiments of the invention were developed which are particularly suited for vertically aligned gas insulated transmission lines. The particle traps are grooves or cavities formed into the walls of the tubular inner conductor, without extending into the hollow portion of the conductor. In other embodiments, the traps are appendages or insert flanges extending from the inner conductor, with the insulator supports contacting the appendages instead of the inner conductor.

Grooved nanowires from self-assembling hairpin molecules for solar cells.

PubMed

Tevis, Ian D; Tsai, Wei-Wen; Palmer, Liam C; Aytun, Taner; Stupp, Samuel I

2012-03-27

One of the challenges facing bulk heterojunction organic solar cells is obtaining organized films during the phase separation of intimately mixed donor and acceptor components. We report here on the use of hairpin-shaped sexithiophene molecules to generate by self-assembly grooved nanowires as the donor component in bulk heterojunction solar cells. Photovoltaic devices were fabricated via spin-casting to produce by solvent evaporation a percolating network of self-assembled nanowires and fullerene acceptors. Thermal annealing was found to increase power conversion efficiencies by promoting domain growth while still maintaining this percolating network of nanostructures. The benefits of self-assembly and grooved nanowires were examined by building devices from a soluble sexithiophene derivative that does not form one-dimensional structures. In these systems, excessive phase separation caused by thermal annealing leads to the formation of defects and lower device efficiencies. We propose that the unique hairpin shape of the self-assembling molecules allows the nanowires as they form to interact well with the fullerenes in receptor-ligand type configurations at the heterojunction of the two domains, thus enhancing device efficiencies by 23%. © 2012 American Chemical Society

Nail findings in patients with psoriatic arthritis: A cross-sectional study with special reference to transverse grooves.

PubMed

Zenke, Yukari; Ohara, Yuri; Kobayashi, Daiki; Arai, Satoru; Kishimoto, Mitsumasa; Okada, Masato; Eto, Hikaru

2017-11-01

Patients with psoriatic arthritis (PsA) commonly present with nail manifestations; however, little is known about these manifestations. This study investigated whether nail findings can be used to discriminate between PsA and psoriasis without arthritis. We performed a retrospective analysis of 118 patients with PsA and 974 patients with psoriasis without arthritis who visited St. Luke's International Hospital (Tokyo, Japan) between July 2003 and February 2015. Patients with PsA were classified according to the Classification of Psoriatic Arthritis criteria. Skin lesion severity was assessed by using the Psoriasis Area and Severity Index, and 9 types of nail findings were investigated. The incidence of nail involvement in patients with PsA was 67.6%. Female sex, presence of transverse grooves, onycholysis, and splinter hemorrhages were significantly related to PsA, with transverse grooves demonstrating the strongest association (odds ratio, 5.01; 95% confidence interval, 2.31-10.8; P < .01). Furthermore, the presence of transverse grooves was strongly related to both distal interphalangeal arthritis and enthesitis. The PsA population was relatively small. Nail findings enabled us to distinguish patients with PsA from those without arthritis. The presence of transverse grooves is significantly associated with PsA and may be associated with distal interphalangeal arthritis and enthesitis. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Simultaneous minimization of leaf travel distance and tongue-and-groove effect for segmental intensity-modulated radiation therapy.

PubMed

Dai, Jianrong; Que, William

2004-12-07

This paper introduces a method to simultaneously minimize the leaf travel distance and the tongue-and-groove effect for IMRT leaf sequences to be delivered in segmental mode. The basic idea is to add a large enough number of openings through cutting or splitting existing openings for those leaf pairs with openings fewer than the number of segments so that all leaf pairs have the same number of openings. The cutting positions are optimally determined with a simulated annealing technique called adaptive simulated annealing. The optimization goal is set to minimize the weighted summation of the leaf travel distance and tongue-and-groove effect. Its performance was evaluated with 19 beams from three clinical cases; one brain, one head-and-neck and one prostate case. The results show that it can reduce the leaf travel distance and (or) tongue-and-groove effect; the reduction of the leaf travel distance reaches its maximum of about 50% when minimized alone; the reduction of the tongue-and-groove reaches its maximum of about 70% when minimized alone. The maximum reduction in the leaf travel distance translates to a 1 to 2 min reduction in treatment delivery time per fraction, depending on leaf speed. If the method is implemented clinically, it could result in significant savings in treatment delivery time, and also result in significant reduction in the wear-and-tear of MLC mechanics.

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Taylor, Brian; Emrich, Bill; Tucker, Dennis; Barnes, Marvin; Donders, Nicolas; Benensky, Kelsa

2018-01-01

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nu- clear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and de ne a fabrication process that will serve for constructing grooved ring fuel rods for large system tests.

Surface diffusivity measurements on 8mol.% yttrium oxide-zirconia bicrystals via grain boundary grooving experiments

NASA Astrophysics Data System (ADS)

Nassirou, Maissarath

Thermal grooving at grain boundaries (GBs) is a capillary-driven evolution of surface topography in the region where the grain boundary emerges at a free surface. The study of these topographic changes can provide insight into surface energetics, and in our particular case, the measurement of surface diffusivity. We have measured the surface diffusion coefficient of 8mol% Y 2O3-ZrO2 by studying the formation of thermal grooves. We studied a total of five bicrystals, with well defined orientation relationships; random [110] -60°, random [001] -30°, Sigma13 [001]/{510}, Sigma13 [001]/{320}, Sigma5 [001]/{210}. Our calculations employed the Herring relation (1951), in which the variation in the chemical potential is related to changes in topography. The samples were annealed at 1300°C and 1400°C for various period of time. Atomic Force Microscopy was used to determine the exact geometry of the thermal grooves. A first approach consisted of estimating the diffusion coefficient by using Mullins' equation. yx=0= dsDs1/ 4gb2g s12G 5/4( WkTgs) 1/4t 1/4 Where y(x =0) is the groove depth at the GB triple junction, O is the atomic volume, gs is the surface tension, gb is the grain boundary surface energy, ds is the thickness of the diffusion layer, t is the annealing time, and Ds is the surface diffusion coefficient. In Mullins' derivation, the atomic structure of the surface was ignored and it was assumed that the surface energy is independent of crystallographic orientation. In the case of zirconia, the surface energy is anisotropic. We will describe in this work a new approach to measuring surface diffusivity which accounts for the surface energy anisotropy. The study of these bicrystals will emphasize the effect of grain boundary structure on the surface diffusion coefficient, and it is for that purpose that we selected bicrystals with different tilt axes and angles. The results obtained using the equation set we have developed will be compared to those obtained by

Olfactory groove meningiomas.

PubMed

Hentschel, Stephen J; DeMonte, Franco

2003-06-15

Olfactory groove meningiomas (OGMs) arise over the cribriform plate and may reach very large sizes prior to presentation. They can be differentiated from tuberculum sellae meningiomas because OGMs arise more anterior in the skull base and displace the optic nerve and chiasm inferiorly rather than superiorly. The authors searched the neurosurgery database at the M. D. Anderson Cancer Center for cases of OGM treated between 1993 and 2003. The records of these patients were then reviewed retrospectively for details regarding clinical presentation, imaging findings, surgical results and complications, and follow-up status. Thirteen patients, (12 women and one man, mean age 56 years) harbored OGMs (mean size 5.7 cm). All patients underwent bifrontal craniotomies and biorbital osteotomies. There were 11 complete resections (including the hyperostotic bone and dura of the cribriform plate and any extension into the ethmoid sinuses) and two subtotal resections with minimal residual tumor left in patients with recurrent lesions. No complication directly due to the surgery occurred in any patient. There were no recurrences in a mean follow-up period of 2 years (range 0-5 years). With current microsurgical techniques, the results of OGM resection are excellent, with a high rate of total resection and a low incidence of complications. All hyperostotic bone should be removed with the dura of the anterior skull base to minimize the risk of recurrence.

A Monofunctional Platinum Complex Coordinated to a Rhodium Metalloinsertor Selectively Binds Mismatched DNA in the Minor Groove

PubMed Central

Weidmann, Alyson G.; Barton, Jacqueline K.

2015-01-01

We report the synthesis and characterization of a bimetallic complex derived from a new family of potent and selective metalloinsertors containing an unusual Rh—O axial coordination. This complex incorporates a monofunctional platinum center containing only one labile site for coordination to DNA, rather than two, and coordinates DNA non-classically through adduct formation in the minor groove. This conjugate displays bifunctional, interdependent binding of mismatched DNA via metalloinsertion at a mismatch as well as covalent platinum binding. DNA sequencing experiments revealed that the preferred site of platinum coordination is not the traditional N7-guanine site in the major groove, but rather N3-adenine in the minor groove. The complex also displays enhanced cytotoxicity in mismatch repair-deficient and mismatch repair-proficient human colorectal carcinoma cell lines compared to the chemotherapeutic cisplatin, and triggers cell death via an apoptotic pathway, rather than the necrotic pathway induced by rhodium metalloinsertors. PMID:26397309

Unusually Strong Binding to the DNA Minor Groove by a Highly Twisted Benzimidazole-Diphenylether: Induced Fit and Bound Water†

PubMed Central

Tanious, Farial A.; Laine, William; Peixoto, Paul; Bailly, Christian; Goodwin, Kristie D.; Lewis, Mark A.; Long, Eric C.; Georgiadis, Millie M.; Tidwell, Richard R.; Wilson, W. David

2008-01-01

RT29 is a dicationic diamidine derivative that does not obey the classical “rules” for shape and functional group placement that are expected to result in strong binding and specific recognition of the DNA minor groove. The compound contains a benzimidazole-diphenyl ether core that is flanked by the amidine cations. The diphenyl ether is highly twisted and gives the entire compound too much curvature to fit well to the shape of the minor groove. DNaseI footprinting, fluorescence intercalator displacement studies and circular dichroism spectra, however, indicate that the compound is an AT specific minor groove binding agent. Even more surprisingly, quantitative biosensor-surface plasmon resonance and isothermal titration calorimetric results indicate that the compound binds with exceptional strength to certain AT sequences in DNA with a large negative enthalpy of binding. Crystallographic results for the DNA complex of RT29 compared to calculated results for the free compound show that the compound undergoes significant conformational changes to enhance its minor groove interactions. In addition, a water molecule is incorporated directly into the complex to complete the compound-DNA interface and it forms an essential link between the compound and base pair edges at the floor of the minor groove. The calculated ΔCp value for complex formation is substantially less than the experimentally observed value in support of water being an intrinsic part of the complex with a major contribution to the ΔCp value. Both the induced fit conformational changes of the compound and the bound water are essential for strong binding to DNA by RT29. PMID:17506529

Microjetting from grooved surfaces in metallic samples subjected to laser driven shocks

NASA Astrophysics Data System (ADS)

de Rességuier, T.; Lescoute, E.; Sollier, A.; Prudhomme, G.; Mercier, P.

2014-01-01

When a shock wave propagating in a solid sample reflects from a free surface, geometrical effects predominantly governed by the roughness and defects of that surface may lead to the ejection of tiny jets that may breakup into high velocity, approximately micrometer-size fragments. This process referred to as microjetting is a major safety issue for engineering applications such as pyrotechnics or armour design. Thus, it has been widely studied both experimentally, under explosive and impact loading, and theoretically. In this paper, microjetting is investigated in the specific loading conditions associated to laser shocks: very short duration of pressure application, very high strain rates, small spatial scales. Material ejection from triangular grooves in the free surface of various metallic samples is studied by combining transverse optical shadowgraphy and time-resolved velocity measurements. The influences of the main parameters (groove angle, shock pressure, nature of the metal) on jet formation and ejection velocity are quantified, and the results are compared to theoretical estimates.

Microjetting from grooved surfaces in metallic samples subjected to laser driven shocks

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

Rességuier, T. de, E-mail: resseguier@ensma.fr; Lescoute, E.; Sollier, A.

2014-01-28

When a shock wave propagating in a solid sample reflects from a free surface, geometrical effects predominantly governed by the roughness and defects of that surface may lead to the ejection of tiny jets that may breakup into high velocity, approximately micrometer-size fragments. This process referred to as microjetting is a major safety issue for engineering applications such as pyrotechnics or armour design. Thus, it has been widely studied both experimentally, under explosive and impact loading, and theoretically. In this paper, microjetting is investigated in the specific loading conditions associated to laser shocks: very short duration of pressure application, verymore » high strain rates, small spatial scales. Material ejection from triangular grooves in the free surface of various metallic samples is studied by combining transverse optical shadowgraphy and time-resolved velocity measurements. The influences of the main parameters (groove angle, shock pressure, nature of the metal) on jet formation and ejection velocity are quantified, and the results are compared to theoretical estimates.« less

Anomalous effective dimensionality of quantum gas adsorption near nanopores.

PubMed

Full, Steven J; McNutt, Jessica P; Cole, Milton W; Mbaye, Mamadou T; Gatica, Silvina M

2010-08-25

Three problems involving quasi-one-dimensional (1D) ideal gases are discussed. The simplest problem involves quantum particles localized within the 'groove', a quasi-1D region created by two adjacent, identical and parallel nanotubes. At low temperature (T), the transverse motion of the adsorbed gas, in the plane perpendicular to the axes of the tubes, is frozen out. Then, the low T heat capacity C(T) of N particles is that of a 1D classical gas: C(*)(T) = C(T)/(Nk(B)) --> 1/2. The dimensionless heat capacity C(*) increases when T ≥ 0.1T(x, y) (transverse excitation temperatures), asymptoting at C(*) = 2.5. The second problem involves a gas localized between two nearly parallel, co-planar nanotubes, with small divergence half-angle γ. In this case, too, the transverse motion does not contribute to C(T) at low T, leaving a problem of a gas of particles in a 1D harmonic potential (along the z axis, midway between the tubes). Setting ω(z) as the angular frequency of this motion, for T ≥ τ(z) ≡ ω(z)ħ/k(B), the behavior approaches that of a 2D classical gas, C(*) = 1; one might have expected instead C(*) = 1/2, as in the groove problem, since the limit γ ≡ 0 is 1D. For T < τ(z), the thermal behavior is exponentially activated, C(*) ∼ (τ(z)/T)(2)e(-τ(z)/T). At higher T (T ≈ ε(y)/k(B) ≡ τ(y) > τ(z)), motion is excited in the y direction, perpendicular to the plane of nanotubes, resulting in thermal behavior (C(*) = 7/4) corresponding to a gas in 7/2 dimensions, while at very high T (T > ħω(x)/k(B) ≡ τ(x) > τ(y)), the behavior becomes that of a D = 11/2 system. The third problem is that of a gas of particles, e.g. (4)He, confined in the interstitial region between four square parallel pores. The low T behavior found in this case is again surprising--that of a 5D gas.

TEM00 mode Nd:YAG solar laser by side-pumping a grooved rod

NASA Astrophysics Data System (ADS)

Vistas, Cláudia R.; Liang, Dawei; Almeida, Joana; Guillot, Emmanuel

2016-05-01

A simple TEM00 mode solar laser system with a grooved Nd:YAG rod pumped through a heliostat-parabolic mirror system is reported here. The radiation coupling capacity of a fused silica tube lens was combined with the multipass pumping ability of a 2 V-shaped cavity to provide efficient side-pumping along a 4.0 mm diameter grooved Nd:YAG single-crystal rod. TEM00 mode solar laser power of 3.4 W was measured by adopting an asymmetric large-mode laser resonant cavity. Record TEM00 mode solar laser collection efficiency of 3.4 W/m2and slope efficiency of 1.9% was achieved, which corresponds to 1.8 and 2.4 times more than the previous TEM00 mode Nd:YAG solar laser using the PROMES-CNRS heliostat-parabolic mirror system, respectively.

Searching for Variability of NV Intrinsic Narrow Absorption Line Systems

NASA Astrophysics Data System (ADS)

Rodruck, Michael; Charlton, Jane; Ganguly, Rajib

2018-01-01

The majority of quasar absorption line systems with NV detected are found within the associated region (within 5000 km/s of the quasar redshift) and many/most are believed to be related to the quasar accretion disk wind or outflows. The most definite evidence that these NV absorbers are "intrinsic" is partial covering of the quasar continuum source and/or broad line region. Over 75 quasars containing NV narrow absorption lines have observations obtained at different times with the Keck/HIRES and the VLT/UVES spectrographs at high resolution. The interval between these observations range from months to a decade in the quasar rest frame. While variability is common for intrinsic broad and mini-broad absorption lines, intrinsic narrow absorption lines have been found to be less likely to vary, though systematic studies with large, high quality datasets have been limited. The variability timescales are useful for deriving gas densities and thus the distances from the central engines. This is important in mapping the quasar surroundings, understanding the accretion disk wind mechanism, and assessing the effect the wind has on the galaxy surroundings. We report on the results of a systematic study of variability of NV NALs, exploiting the overlap of targets for observations in the archives of Keck and VLT, and discuss the consequences for interpretation of the origin of intrinsic narrow absorption lines.

Quantum spill-out in few-nanometer metal gaps: Effect on gap plasmons and reflectance from ultrasharp groove arrays

NASA Astrophysics Data System (ADS)

Skjølstrup, Enok J. H.; Søndergaard, Thomas; Pedersen, Thomas G.

2018-03-01

Plasmons in ultranarrow metal gaps are highly sensitive to the electron density profile at the metal surfaces. Using a quantum mechanical approach and assuming local response, we study the effects of electron spill-out on gap plasmons and reflectance from ultrasharp metal grooves. We demonstrate that the mode index of ultranarrow gap plasmons converges to the bulk refractive index in the limit of vanishing gap and, thereby, rectify the unphysical divergence found in classical models. Surprisingly, spill-out also significantly increases the plasmonic absorption for few-nanometer gaps and lowers the reflectance from arrays of ultrasharp metal grooves. These findings are explained in terms of enhanced gap plasmon absorption taking place inside the gap 1-2 Å from the walls and delocalization near the groove bottom. Reflectance calculations taking spill-out into account are shown to be in much better agreement with measurements compared with classical models.

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Taylor, Brian; Emrich, Bill; Tucker, Dennis; Barnes, Marvin; Donders, Nicolas; Benensky, Kelsa

2018-01-01

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nuclear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are discussed. The authors demonstrated success in reaching desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and define a fabrication process that will serve for constructing grooved ring fuel rods for large system tests.

Light effects in the atomic-motion-induced Ramsey narrowing of dark resonances in wall-coated cells

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

Breschi, E.; Schori, C.; Di Domenico, G.

2010-12-15

We report on light shift and broadening in the atomic-motion-induced Ramsey narrowing of dark resonances prepared in alkali-metal vapors contained in wall-coated cells without buffer gas. The atomic-motion-induced Ramsey narrowing is due to the free motion of the polarized atomic spins in and out of the optical interaction region before spin relaxation. As a consequence of this effect, we observe a narrowing of the dark resonance linewidth as well as a reduction of the ground states' light shift when the volume of the interaction region decreases at constant optical intensity. The results can be intuitively interpreted as a dilution ofmore » the intensity effect similar to a pulsed interrogation due to the atomic motion. Finally the influence of this effect on the performance of compact atomic clocks is discussed.« less

Standardized performance tests of collectors of solar thermal energy: Prototype moderately concentrating grooved collectors

NASA Technical Reports Server (NTRS)

1976-01-01

Prototypes of moderately concentrating grooved collectors were tested with a solar simulator for varying inlet temperature, flux level, and incident angle. Collector performance is correlated in terms of inlet temperature and flux level.

Effects of reset stators and a rotating, grooved stator hub on performance of a 1.92-pressure-ratio compressor stage

NASA Technical Reports Server (NTRS)

Lewis, G. W., Jr.; Urasek, D. C.; Reid, L.

1977-01-01

The overall performance and blade-element performance of a transonic fan stage are presented for two modified test configurations and are compared with the unmodified stage. Tests were conducted with reset stators 2 deg open and reset stators with a rotating grooved stator hub. Detailed radial and circumferential (behind stator) surveys of the flow conditions were made over the stable operating range at rotative speeds of 70, 90, and 100 percent of design speed. Reset stator blade tests indicated a small increase in stage efficiency, pressure ratio, and maximum weight flow at each speed. Performance with reset stators and a rotating, grooved stator hub resulted in an additional increase in stage efficiency and pressure ratio at all speeds. The rotating grooved stator hub reduced hub losses considerably.

Commissioning of the tongue-and-groove modelling in treatment planning systems: from static fields to VMAT treatments

NASA Astrophysics Data System (ADS)

Hernandez, Victor; Vera-Sánchez, Juan Antonio; Vieillevigne, Laure; Saez, Jordi

2017-08-01

Adequate modelling of the multi-leaf collimator (MLC) by treatment planning systems (TPS) is essential for accurate dose calculations in intensity-modulated radiation-therapy. For this reason modern TPSs incorporate MLC characteristics such as the leaf end curvature, MLC transmission and the tongue-and-groove. However, the modelling of the tongue-and-groove is often neglected during TPS commissioning and it is not known how accurate it is. This study evaluates the dosimetric consequences of the tongue-and-groove effect for two different MLC models using both film dosimetry and ionisation chambers. A set of comprehensive tests are presented that evaluate the ability of TPSs to accurately model this effect in (a) static fields, (b) sliding window beams and (c) VMAT arcs. The tests proposed are useful for the commissioning of TPSs and for the validation of major upgrades. With the ECLIPSE TPS, relevant differences were found between calculations and measurements for beams with dynamic MLCs in the presence of the TG effect, especially for the High Definition MLC, small gap sizes and the 1 mm calculation grid. For this combination, dose differences as high as 10% and 7% were obtained for dynamic MLC gaps of 5 mm and 10 mm, respectively. These differences indicate inadequate modelling of the tongue-and-groove effect, which might not be identified without the proposed tests. In particular, the TPS tended to underestimate the calculated dose, which may require tuning of other configuration parameters in the TPS (such as the dosimetric leaf gap) in order to maximise the agreement between calculations and measurements in clinical plans. In conclusion, a need for better modelling of the MLC by TPSs is demonstrated, one of the relevant aspects being the tongue-and-groove effect. This would improve the accuracy of TPS calculations, especially for plans using small MLC gaps, such as plans with small target volumes or high complexities. Improved modelling of the MLC would

Biomimetic "Cactus Spine" with Hierarchical Groove Structure for Efficient Fog Collection.

PubMed

Bai, Fan; Wu, Juntao; Gong, Guangming; Guo, Lin

2015-07-01

A biomimetic "cactus spine" with hierarchical groove structure is designed and fabricated using simple electrospinning. This novel artificial cactus spine possesses excellent fog collection and water transportation ability. A model cactus equipped with artificial spines also shows a great water storage capacity. The results can be helpful in the development of water collectors and may make a contribution to the world water crisis.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

PubMed

Youssef, A Samy; Sampath, Raghuram; Freeman, Jacob L; Mattingly, Jameson K; Ramakrishnan, Vijay R

2016-10-01

Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus. An expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction. The surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia. Olfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.

Sectoral combustor for burning low-BTU fuel gas

DOEpatents

Vogt, Robert L.

1980-01-01

A high-temperature combustor for burning low-BTU coal gas in a gas turbine is disclosed. The combustor includes several separately removable combustion chambers each having an annular sectoral cross section and a double-walled construction permitting separation of stresses due to pressure forces and stresses due to thermal effects. Arrangements are described for air-cooling each combustion chamber using countercurrent convective cooling flow between an outer shell wall and an inner liner wall and using film cooling flow through liner panel grooves and along the inner liner wall surface, and for admitting all coolant flow to the gas path within the inner liner wall. Also described are systems for supplying coal gas, combustion air, and dilution air to the combustion zone, and a liquid fuel nozzle for use during low-load operation. The disclosed combustor is fully air-cooled, requires no transition section to interface with a turbine nozzle, and is operable at firing temperatures of up to 3000.degree. F. or within approximately 300.degree. F. of the adiabatic stoichiometric limit of the coal gas used as fuel.

Minor groove RNA triplex in the crystal structure of a ribosomal frameshifting viral pseudoknot

NASA Technical Reports Server (NTRS)

Su, L.; Chen, L.; Egli, M.; Berger, J. M.; Rich, A.

1999-01-01

Many viruses regulate translation of polycistronic mRNA using a -1 ribosomal frameshift induced by an RNA pseudoknot. A pseudoknot has two stems that form a quasi-continuous helix and two connecting loops. A 1.6 A crystal structure of the beet western yellow virus (BWYV) pseudoknot reveals rotation and a bend at the junction of the two stems. A loop base is inserted in the major groove of one stem with quadruple-base interactions. The second loop forms a new minor-groove triplex motif with the other stem, involving 2'-OH and triple-base interactions, as well as sodium ion coordination. Overall, the number of hydrogen bonds stabilizing the tertiary interactions exceeds the number involved in Watson-Crick base pairs. This structure will aid mechanistic analyses of ribosomal frameshifting.

Strong minor groove base conservation in sequence logos implies DNA distortion or base flipping during replication and transcription initiation.

PubMed

Schneider, T D

2001-12-01

The sequence logo for DNA binding sites of the bacteriophage P1 replication protein RepA shows unusually high sequence conservation ( approximately 2 bits) at a minor groove that faces RepA. However, B-form DNA can support only 1 bit of sequence conservation via contacts into the minor groove. The high conservation in RepA sites therefore implies a distorted DNA helix with direct or indirect contacts to the protein. Here I show that a high minor groove conservation signature also appears in sequence logos of sites for other replication origin binding proteins (Rts1, DnaA, P4 alpha, EBNA1, ORC) and promoter binding proteins (sigma(70), sigma(D) factors). This finding implies that DNA binding proteins generally use non-B-form DNA distortion such as base flipping to initiate replication and transcription.

Narrow band gap amorphous silicon semiconductors

DOEpatents

Madan, A.; Mahan, A.H.

1985-01-10

Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

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

Pascucci, I.; Simon, M. N.; Edwards, S.

2015-11-20

We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within themore » circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.« less

Effectiveness of noise barriers installed adjacent to transverse grooved concrete pavement : executive summary report.

DOT National Transportation Integrated Search

2009-10-16

In recent years the Ohio Department of Transportation (ODOT) has reconstructed a number of roadways where asphalt pavements were replaced with concrete pavements which were finished with a random transverse grooved surface texture (ODOT specification...

Automated two-dimensional interface for capillary gas chromatography

DOEpatents

Strunk, M.R.; Bechtold, W.E.

1996-02-20

A multidimensional gas chromatograph (GC) system is disclosed which has wide bore capillary and narrow bore capillary GC columns in series and has a novel system interface. Heart cuts from a high flow rate sample, separated by a wide bore GC column, are collected and directed to a narrow bore GC column with carrier gas injected at a lower flow compatible with a mass spectrometer. A bimodal six-way valve is connected with the wide bore GC column outlet and a bimodal four-way valve is connected with the narrow bore GC column inlet. A trapping and retaining circuit with a cold trap is connected with the six-way valve and a transfer circuit interconnects the two valves. The six-way valve is manipulated between first and second mode positions to collect analyte, and the four-way valve is manipulated between third and fourth mode positions to allow carrier gas to sweep analyte from a deactivated cold trap, through the transfer circuit, and then to the narrow bore GC capillary column for separation and subsequent analysis by a mass spectrometer. Rotary valves have substantially the same bore width as their associated columns to minimize flow irregularities and resulting sample peak deterioration. The rotary valves are heated separately from the GC columns to avoid temperature lag and resulting sample deterioration. 3 figs.

Automated two-dimensional interface for capillary gas chromatography

DOEpatents

Strunk, Michael R.; Bechtold, William E.

1996-02-20

A multidimensional gas chromatograph (GC) system having wide bore capillary and narrow bore capillary GC columns in series and having a novel system interface. Heart cuts from a high flow rate sample, separated by a wide bore GC column, are collected and directed to a narrow bore GC column with carrier gas injected at a lower flow compatible with a mass spectrometer. A bimodal six-way valve is connected with the wide bore GC column outlet and a bimodal four-way valve is connected with the narrow bore GC column inlet. A trapping and retaining circuit with a cold trap is connected with the six-way valve and a transfer circuit interconnects the two valves. The six-way valve is manipulated between first and second mode positions to collect analyte, and the four-way valve is manipulated between third and fourth mode positions to allow carrier gas to sweep analyte from a deactivated cold trap, through the transfer circuit, and then to the narrow bore GC capillary column for separation and subsequent analysis by a mass spectrometer. Rotary valves have substantially the same bore width as their associated columns to minimize flow irregularities and resulting sample peak deterioration. The rotary valves are heated separately from the GC columns to avoid temperature lag and resulting sample deterioration.

Definition of a simple statistical parameter for the quantification of orientation in two dimensions: application to cells on grooves of nanometric depths.

PubMed

Davidson, P; Bigerelle, M; Bounichane, B; Giazzon, M; Anselme, K

2010-07-01

Contact guidance is generally evaluated by measuring the orientation angle of cells. However, statistical analyses are rarely performed on these parameters. Here we propose a statistical analysis based on a new parameter sigma, the orientation parameter, defined as the dispersion of the distribution of orientation angles. This parameter can be used to obtain a truncated Gaussian distribution that models the distribution of the data between -90 degrees and +90 degrees. We established a threshold value of the orientation parameter below which the data can be considered to be aligned within a 95% confidence interval. Applying our orientation parameter to cells on grooves and using a modelling approach, we established the relationship sigma=alpha(meas)+(52 degrees -alpha(meas))/(1+C(GDE)R) where the parameter C(GDE) represents the sensitivity of cells to groove depth, and R the groove depth. The values of C(GDE) obtained allowed us to compare the contact guidance of human osteoprogenitor (HOP) cells across experiments involving different groove depths, times in culture and inoculation densities. We demonstrate that HOP cells are able to identify and respond to the presence of grooves 30, 100, 200 and 500 nm deep and that the deeper the grooves, the higher the cell orientation. The evolution of the sensitivity (C(GDE)) with culture time is roughly sigmoidal with an asymptote, which is a function of inoculation density. The sigma parameter defined here is a universal parameter that can be applied to all orientation measurements and does not require a mathematical background or knowledge of directional statistics. Copyright 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Flight trajectory of a rotating golf ball with grooves

NASA Astrophysics Data System (ADS)

Baek, Moonheum; Kim, Jooha; Choi, Haecheon

2014-11-01

Dimples are known to reduce drag on a sphere by the amount of 50% as compared to a smooth surface. Despite the advantage of reducing drag, dimples deteriorate the putting accuracy owing to their sharp edges. To minimize this putting error but maintain the same flight distance, we have devised a grooved golf ball (called G ball hereafter) for several years. In this study, we modify the shape and pattern of grooves, and investigate the flow characteristics of the G ball by performing wind-tunnel experiments at the Reynolds numbers of 0 . 5 ×105 - 2 . 5 ×105 and the spin ratios (ratio of surface velocity to the free-stream velocity) of 0 - 0.6 that include the real golf-ball velocity and rotational speed. We measure the drag and lift forces on the rotating G ball and compare them with those of a smooth ball and two well-known dimpled balls. The lift-to-drag ratio of the G ball is much higher than that of a smooth ball and is in between those of the two dimpled balls. The trajectories of flying golf balls are computed. The flight distance of G ball is almost the same as that of one dimpled ball but slightly shorter than that of the other dimpled ball. The fluid-dynamic aspects of these differences will be discussed at the talk. Supported by 2011-0028032, 2014M3C1B1033980.

Analysis of behavior of focusing error signals generated by astigmatic method when a focused spot moves beyond the radius of a land-groove-type optical disk

NASA Astrophysics Data System (ADS)

Shinoda, Masahisa; Nakatani, Hidehiko; Nakai, Kenya; Ohmaki, Masayuki

2015-09-01

We theoretically calculate behaviors of focusing error signals generated by an astigmatic method in a land-groove-type optical disk. The focusing error signal from the land does not coincide with that from the groove. This behavior is enhanced when a focused spot of an optical pickup moves beyond the radius of the optical disk. A gain difference between the slope sensitivities of focusing error signals from the land and the groove is an important factor with respect to stable focusing servo control. In our calculation, the format of digital versatile disc-random access memory (DVD-RAM) is adopted as the land-groove-type optical disk model, and the dependences of the gain difference on various factors are investigated. The gain difference strongly depends on the optical intensity distribution of the laser beam in the optical pickup. The calculation method and results in this paper will be reflected in newly developed land-groove-type optical disks.

Comparison of microstructure and mechanical properties of ultra-narrow gap laser and gas-metal-arc welded S960 high strength steel

NASA Astrophysics Data System (ADS)

Guo, Wei; Li, Lin; Dong, Shiyun; Crowther, Dave; Thompson, Alan

2017-04-01

The microstructural characteristics and mechanical properties, including micro-hardness, tensile properties, three-point bending properties and Charpy impact toughness at different test temperatures of 8 mm thick S960 high strength steel plates were investigated following their joining by multi-pass ultra-narrow gap laser welding (NGLW) and gas metal arc welding (GMAW) techniques. It was found that the microstructure in the fusion zone (FZ) for the ultra-NGLW joint was predominantly martensite mixed with some tempered martensite, while the FZ for the GMAW joint was mainly consisted of ferrite with some martensite. The strength of the ultra-NGLW specimens was comparable to that of the base material (BM), with all welded specimens failed in the BM in the tensile tests. The tensile strength of the GMAW specimens was reduced approximately by 100 MPa when compared with the base material by a broad and soft heat affected zone (HAZ) with failure located in the soft HAZ. Both the ultra-NGLW and GMAW specimens performed well in three-point bending tests. The GMAW joints exhibited better impact toughness than the ultra-NGLW joints.

Nanoscale Plasmonic V-Groove Waveguides for the Interrogation of Single Fluorescent Bacterial Cells.

PubMed

Lotan, Oren; Bar-David, Jonathan; Smith, Cameron L C; Yagur-Kroll, Sharon; Belkin, Shimshon; Kristensen, Anders; Levy, Uriel

2017-09-13

We experimentally demonstrate the interrogation of an individual Escherichia coli cell using a nanoscale plasmonic V-groove waveguide. Several different configurations were studied. The first involved the excitation of the cell in a liquid environment because it flows on top of the waveguide nanocoupler, while the obtained fluorescence is coupled into the waveguide and collected at the other nanocoupler. The other two configurations involved the positioning of the bacterium within the nanoscale waveguide and its excitation in a dry environment either directly from the top or through waveguide modes. This is achieved by taking advantage of the waveguide properties not only for light guiding but also as a mechanical tool for trapping the bacteria within the V-grooves. The obtained results are supported by a set of numerical simulations, shedding more light on the mechanism of excitation. This demonstration paves the way for the construction of an efficient bioplasmonic chip for diverse cell-based sensing applications.

Gas film disturbance characteristics analysis of high-speed and high-pressure dry gas seal

NASA Astrophysics Data System (ADS)

Chen, Yuan; Jiang, Jinbo; Peng, Xudong

2016-08-01

The dry gas seal(DGS) has been widely used in high parameters centrifugal compressor, but the intense vibrations of shafting, especially in high-speed condition, usually result in DGS's failure. So the DGS's ability of resisting outside interference has become a determining factor of the further development of centrifugal compressor. However, the systematic researches of which about gas film disturbance characteristics of high parameters DGS are very little. In order to study gas film disturbance characteristics of high-speed and high-pressure spiral groove dry gas seal(S-DGS) with a flexibly mounted stator, rotor axial runout and misalignment are taken into consideration, and the finite difference method and analytical method are used to analyze the influence of gas film thickness disturbance on sealing performance parameters, what's more, the effects of many key factors on gas film thickness disturbance are systematically investigated. The results show that, when sealed pressure is 10.1MPa and seal face average linear velocity is 107.3 m/s, gas film thickness disturbance has a significant effect on leakage rate, but has relatively litter effect on open force; Excessively large excitation amplitude or excessively high excitation frequency can lead to severe gas film thickness disturbance; And it is beneficial to assure a smaller gas film thickness disturbance when the stator material density is between 3.1 g/cm3 to 8.4 g/cm3; Ensuring sealing performance while minimizing support axial stiffness and support axial damping can help to improve dynamic tracking property of dry gas seal. The proposed research provides the instruction to optimize dynamic tracking property of the DGS.

Enhancement of fluorescence quenching and exciplex formation in DNA major groove by double incorporation of modified fluorescent deoxyuridines.

PubMed

Tanaka, Makiko; Oguma, Kazuhiro; Saito, Yoshio; Saito, Isao

2012-06-15

5-(1-Naphthalenylethynyl)-2'-deoxyuridine ((N)U) and 5-[(4-cyano-1-naphthalenyl)ethynyl]-2'-deoxyuridine ((CN)U) were synthesized and incorporated into oligodeoxynucleotides. Fluorescence emissions of modified duplexes containing double (N)U were efficiently quenched depending upon the sequence pattern of the naphthalenes in DNA major groove, as compared to the duplex possessing single (N)U. When one of the naphthalene moieties has a cyano substituent, the exciplex emission from the chromophores in DNA major groove was observed at longer wavelength. Copyright © 2012 Elsevier Ltd. All rights reserved.

Generalized Stability Analysis of Capillary Flow in Slender V-Grooves

NASA Astrophysics Data System (ADS)

White, Nicholas; Troian, Sandra

2017-11-01

Spontaneous capillary flow, an especially rapid process in slender open microchannels resembling V-grooves, is of significant importance to many applications requiring passive robust flow control. Many types of biomedical devices for point-of-care use in developing countries are being designed around this principle. Important fundamental work by Romero and Yost (1996) and Weislogel (1996) elucidated the behavior of Newtonian films in slender V-grooves driven to flow by the streamwise change in capillary pressure due to the change in radius of curvature of the circular arc describing the interface of wetting or non-wetting fluids. Self-similar solutions describing Washburn type dynamics were found but other solutions are possible. Here we extend the Romero and Yost model to include a variety of inlet and outlet boundary conditions and examine the transient growth and generalized stability of perturbations to steady state and self-similar flows. Although most cases examined for wetting fluids exhibit robust stability against small perturbations, some exceptions reveal unstable flow. In total, these results support decades of experimental work which has found this method of flow control to be especially reliable, robust and self-healing. The authors gratefully acknowledge financial support from the 2016 NASA/Jet Propulsion Laboratory President's and Director's Fund as well as a 2017 NASA Space Technology Research Fellowship.

Design, fabrication and test of a hydrogen heat pipe. [extruding and grooving 6063-T6 aluminum tubes for cryogenic heat pipes

NASA Technical Reports Server (NTRS)

Alario, J.

1979-01-01

Re-entrant groove technology was extended to hydrogen heat pipes. Parametric analyses are presented which optimize the theoretical design while considering the limitations of state-of-the-art extrusion technology. The 6063-T6 aluminum extrusion is 14.6 mm OD with a wall thickness of 1.66 mm and contains 20 axial grooves which surround a central 9.3 mm diameter vapor core. Each axial groove is 0.775 mm diameter with a 0.33 mm opening. An excess vapor reservoir is provided at the evaporator to minimize the pressure containment hazard during ambient storage. Modifications to the basic re-entrant groove profile resulted in improved overall performance. While the maximum heat transport capacity decreased slightly to 103 w-m the static wicking height increased markedly to 4.5 cm. The heat pipe became operational between 20 and 30 K after a cooldown from 77 K without any difficulty. Steady state performance data taken over a 19 to 23 K temperature range indicated: (1) maximum heat transport capacity of 5.4 w-m; (2) static wicking height of 1.42 cm; and (3) overall heat pipe conductance of 1.7 watts/deg C.

Enhanced Broadband Electromagnetic Absorption in Silicon Film with Photonic Crystal Surface and Random Gold Grooves Reflector

PubMed Central

Chen, Zhi-Hui; Qiao, Na; Yang, Yibiao; Ye, Han; Liu, Shaoding; Wang, Wenjie; Wang, Yuncai

2015-01-01

We show a hybrid structure consisting of Si film with photonic crystal surface and random triangular gold grooves reflector at the bottom, which is capable of realizing efficient, broad-band, wide-angle optical absorption. It is numerically demonstrated that the enhanced absorption in a broad wavelength range (0.3–9.9 μm) due to the scattering effect of both sides of the structure and the created resonance modes. Larger thickness and period are favored to enhance the absorption in broader wavelength range. Substantial electric field concentrates in the grooves of surface photonic crystal and in the Si film. Our structure is versatile for solar cells, broadband photodetection and stealth coating. PMID:26238270

Time-resolved measurement of single pulse femtosecond laser-induced periodic surface structure formation induced by a pre-fabricated surface groove.

PubMed

Kafka, K R P; Austin, D R; Li, H; Yi, A Y; Cheng, J; Chowdhury, E A

2015-07-27

Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a single femtosecond laser pulse (pump) with a nano-scale groove mechanically formed on a single-crystal Cu substrate. The interaction dynamics (0-1200 ps) was captured by diffracting a time-delayed, frequency-doubled pulse (probe) from nascent LIPSS formation induced by the pump with an infinity-conjugate microscopy setup. The LIPSS ripples are observed to form asynchronously, with the first one forming after 50 ps and others forming sequentially outward from the groove edge at larger time delays. A 1-D analytical model of electron heating including both the laser pulse and surface plasmon polariton excitation at the groove edge predicts ripple period, melt spot diameter, and qualitatively explains the asynchronous time-evolution of LIPSS formation.

Electrophoresis in ice surface grooves for probing protein affinity to a specific plane of ice crystal.

PubMed

Inagawa, Arinori; Okada, Yusuke; Okada, Tetsuo

2018-06-01

Channel-like grooves are formed on the surface of frozen aqueous sucrose. They are filled with a freeze concentrated solution (FCS) and act as an efficient size-tunable separation field for micro and nanoparticles. The width of the channel can be easily varied by changing the temperature. Because the channel width decreases with decreasing temperature, particles become immobilized due to physical interference from the ice wall when the temperature reaches a threshold point specific to the particle size. Surface modification of particles can add a factor of chemical interaction between the particles and ice walls. In this study, anti-freeze proteins (AFPs) are anchored on 1µm-polystyrene (PS) particles, and their behavior in the surface grooves on the ice is studied. The threshold temperature is an effective criterion for evaluating chemical interactions between particles and ice walls. The AFP binding on 1µm PS particles lowers the threshold temperature by 2.5°C, indicating interactions between AFPs on the PS particles and the ice wall. Because the AFPs studied here show selectivity towards the prism plane, it is critical that the prism plane of the ice crystal is in contact with the FCS in the surface grooves. Copyright © 2017 Elsevier B.V. All rights reserved.

NDE and DE of PWSCC Found in the J-Groove Weld of a Removed-From-Service Control Rod Drive Mechanism

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

Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.

2008-01-01

Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. Two CRDM assemblies were removed from service, decontaminated, and thenmore » used in a series of laboratory NDE and DE measurements; this report addresses the following questions: 1) What did each NDE technique detect?, 2) What did each NDE technique miss?, 3) How accurately did each NDE technique characterize the detected flaws?, and finally 4) What were the basis for the NDE techniques performance? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. This paper focuses on a CRDM assembly that contained suspected PWSCC, based on in-service inspection data and through-wall leakage. The laboratory NDE measurements used to examine the CRDM assembly followed standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. These techniques included eddy current testing, time of flight diffraction ultrasound, and penetrant testing. In addition, other laboratory-based NDE methods were employed to conduct inspections of the CRDM assembly with particular emphasis on inspecting the J-groove weld and buttering. These techniques included volumetric ultrasonic inspection of the J-groove weld metal, visual testing via replicant material of the J-groove weld and high resolution

Interaction of Nevirapine with the Peptide Binding Groove of HLA-DRB1*01:01 and Its Effect on the Conformation of HLA-Peptide Complex.

PubMed

Hirasawa, Makoto; Hagihara, Katsunobu; Abe, Koji; Ando, Osamu; Hirayama, Noriaki

2018-06-04

Human leukocyte antigen (HLA)-DRB1*01:01 has been shown to be involved in nevirapine-induced hepatic hypersensitivity reactions. In the present study, in silico docking simulations and molecular dynamics simulations were performed to predict the interaction mode of nevirapine with the peptide binding groove of HLA-DRB1*01:01 and its possible effect on the position and orientation of the ligand peptide derived from hemagglutinin (HA). In silico analyses suggested that nevirapine interacts with HLA-DRB1*01:01 around the P4 pocket within the peptide binding groove and the HA peptide stably binds on top of nevirapine at the groove. The analyses also showed that binding of nevirapine at the groove will significantly change the inter-helical distances of the groove. An in vitro competitive assay showed that nevirapine (1000 μM) increases the binding of the HA peptide to HLA-DRB1*01:01 in an allele-specific manner. These results indicate that nevirapine might interact directly with the P4 pocket and modifies its structure, which could change the orientation of loaded peptides and the conformation of HLA-DRB1*01:01; these changes could be distinctively recognized by T-cell receptors. Through this molecular mechanism, nevirapine might stimulate the immune system, resulting in hepatic hypersensitivity reactions.

Functional specificity of a Hox protein mediated by the recognition of minor groove structure.

PubMed

Joshi, Rohit; Passner, Jonathan M; Rohs, Remo; Jain, Rinku; Sosinsky, Alona; Crickmore, Michael A; Jacob, Vinitha; Aggarwal, Aneel K; Honig, Barry; Mann, Richard S

2007-11-02

The recognition of specific DNA-binding sites by transcription factors is a critical yet poorly understood step in the control of gene expression. Members of the Hox family of transcription factors bind DNA by making nearly identical major groove contacts via the recognition helices of their homeodomains. In vivo specificity, however, often depends on extended and unstructured regions that link Hox homeodomains to a DNA-bound cofactor, Extradenticle (Exd). Using a combination of structure determination, computational analysis, and in vitro and in vivo assays, we show that Hox proteins recognize specific Hox-Exd binding sites via residues located in these extended regions that insert into the minor groove but only when presented with the correct DNA sequence. Our results suggest that these residues, which are conserved in a paralog-specific manner, confer specificity by recognizing a sequence-dependent DNA structure instead of directly reading a specific DNA sequence.

Evaluation of a Spiral Groove Geometry for Improvement of Hemolysis Level in a Hydrodynamically Levitated Centrifugal Blood Pump.

PubMed

Murashige, Tomotaka; Kosaka, Ryo; Sakota, Daisuke; Nishida, Masahiro; Kawaguchi, Yasuo; Yamane, Takashi; Maruyama, Osamu

2015-08-01

The purpose of this study is to evaluate a spiral groove geometry for a thrust bearing to improve the hemolysis level in a hydrodynamically levitated centrifugal blood pump. We compared three geometric models: (i) the groove width is the same as the ridge width at any given polar coordinate (conventional model); (ii) the groove width contracts inward from 9.7 to 0.5 mm (contraction model); and (iii) the groove width expands inward from 0.5 to 4.2 mm (expansion model). To evaluate the hemolysis level, an impeller levitation performance test and in vitro hemolysis test were conducted using a mock circulation loop. In these tests, the driving conditions were set at a pressure head of 200 mm Hg and a flow rate of 4.0 L/min. As a result of the impeller levitation performance test, the bottom bearing gaps of the contraction and conventional models were 88 and 25 μm, respectively. The impeller of the expansion model touched the bottom housing. In the hemolysis test, the relative normalized index of hemolysis (NIH) ratios of the contraction model in comparison with BPX-80 and HPM-15 were 0.6 and 0.9, respectively. In contrast, the relative NIH ratios of the conventional model in comparison with BPX-80 and HPM-15 were 9.6 and 13.7, respectively. We confirmed that the contraction model achieved a large bearing gap and improved the hemolysis level in a hydrodynamically levitated centrifugal blood pump. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Scary gas: a spectrum of soft tissue gas encountered in the axial body (part II).

PubMed

Sandstrom, Claire K; Osman, Sherif F; Linnau, Ken F

2017-08-01

Ectopic gas in the mediastinum, subperitoneal abdomen, and superficial soft tissues is concerning and can be seen in the setting of trauma, iatrogenic injuries, infection, and inflammation. It can spread along different dissection pathways and may present remotely from the involved organ as described in part one. Recognition of ectopic gas on imaging and differentiating it from other causes of benign gas is very important as these conditions associated with ectopic gas can lead to rapid patient deterioration and usually require urgent surgery. In part two, the different causes of ectopic and benign gas in the torso are reviewed as well as the imaging features that can help to narrow the differential diagnosis.

All metal valve structure for gas systems

DOEpatents

Baker, Ray W.; Pawlak, Donald A.; Ramey, Alford J.

1984-11-13

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

All-metal valve structure for gas systems

DOEpatents

Baker, R.W.; Pawlak, D.A.; Ramey, A.J.

1982-06-10

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

Computer-Aided Drug Discovery: Molecular Docking of Diminazene Ligands to DNA Minor Groove

ERIC Educational Resources Information Center

Kholod, Yana; Hoag, Erin; Muratore, Katlynn; Kosenkov, Dmytro

2018-01-01

The reported project-based laboratory unit introduces upper-division undergraduate students to the basics of computer-aided drug discovery as a part of a computational chemistry laboratory course. The students learn to perform model binding of organic molecules (ligands) to the DNA minor groove with computer-aided drug discovery (CADD) tools. The…

Processing of high-precision ceramic balls with a spiral V-groove plate

NASA Astrophysics Data System (ADS)

Feng, Ming; Wu, Yongbo; Yuan, Julong; Ping, Zhao

2017-03-01

As the demand for high-performance bearings gradually increases, ceramic balls with excellent properties, such as high accuracy, high reliability, and high chemical durability used, are extensively used for highperformance bearings. In this study, a spiral V-groove plate method is employed in processing high-precision ceramic balls. After the kinematic analysis of the ball-spin angle and enveloped lapping trajectories, an experimental rig is constructed and experiments are conducted to confirm the feasibility of this method. Kinematic analysis results indicate that the method not only allows for the control of the ball-spin angle but also uniformly distributes the enveloped lapping trajectories over the entire ball surface. Experimental results demonstrate that the novel spiral Vgroove plate method performs better than the conventional concentric V-groove plate method in terms of roundness, surface roughness, diameter difference, and diameter decrease rate. Ceramic balls with a G3-level accuracy are achieved, and their typical roundness, minimum surface roughness, and diameter difference are 0.05, 0.0045, and 0.105 μm, respectively. These findings confirm that the proposed method can be applied to high-accuracy and high-consistency ceramic ball processing.

Dynamic Behavior of Spiral-Groove and Rayleigh-Step Self-Acting Face Seals

NASA Technical Reports Server (NTRS)

Dirusso, Eliseo

1984-01-01

Tests were performed to determine the dynamic behavior and establish baseline dynamic data for five self-acting face seals employing Rayleigh-step lift-pads and inward pumping as well as outward-pumping spiral grooves for the lift-generating mechanism. The primary parameters measured in the tests were film thickness, seal seat axial motion, and seal frictional torque. The data show the dynamic response of the film thickness to the motion of the seal seat. The inward-pumping spiral-groove seals exhibited a high-amplitude film thickness vibratory mode with a frequency of four times the shaft speed. This mode was not observed in the other seals tested. The tests also revealed that high film thickness vibration amplitude produces considerably higher average film thickness than do low amplitude film thickness vibrations. The seals were tested at a constant face load of 73 N (16.4 lb) with ambient air at room temperature and atmospheric pressure as the fluid medium. The test speed range was from 7000 to 17000 rpm. Seal tangential speed range was 34.5 to 83.7 m/sec (113 to 274 ft/sec).

A Novel Infrared Gas Monitor

NASA Astrophysics Data System (ADS)

Wang, Yingding; Zhong, Hongjie

2000-03-01

In the paper a novel non-dispersive infrared(IR) gas monitor is described.It is based on the principle that certain gases absorb IR radiation at specific(and often unique) wavelengths.Conventional devices typically include several primary components:a broadband source, usually an incandescent filament,a rotating chopper shutter,a narrow-band filter,a sample tube and a detector. We have developed a number of IR light emitting diodes(LED) having narrow optical bandwidths and which can be intensity modulated by electrical means,for example InAsSbP(4.2 micron)LED.The IR LED can thus replace the thermal source,narrow-band filter and chopper assembly of the conventional IR gas monitor,yielding a solid state,low- powered,compact and almost maintenance-free instrument with high sensitivity and stability and which free of the effects of mechanical vibration too. The detector used in the IR gas monitor is the solid-state detector,such as PbS,PbSe, InSb,HgCdTe,TGS,LT and PZT detector etc. The different configuration of the IR gas monitor is designed.For example,two-path version for measuring methane concentration by monitoring the 3.31 micron absorption band,it can eliminate the interference effects,such as to compensate for LED intensity changes caused by power and temperature variations,and for signal fluctuations due to changes in detector bias. we also have designed portable single-beam version without the sample tube.Its most primary advantage is very cheap(about cost USD 30 ).It measures carbon dioxide concentration by monitoring the 4.25 micron absorption band.Thought its precisions is low,it is used to control carbon dioxide concentration in the air in the green houses and plastic houses(there are about twenty millon one in the China).Because more carbon dioxide will increase the quanity of vegetable and flower production to a greatextent. It also is used in medical,sanitary and antiepidemic applications,such as hospital, store,hotel,cabin and ballroom etc. Key words

Analysis of mandibular second molars with fused roots and shallow radicular grooves by using micro-computed tomography.

PubMed

Amoroso-Silva, Pablo; De Moraes, Ivaldo Gomes; Marceliano-Alves, Marilia; Bramante, Clovis Monteiro; Zapata, Ronald Ordinola; Hungaro Duarte, Marco Antonio

2018-01-01

This study aimed to describe the morphological and morphometric aspects of fused mandibular second molars with radicular shallow grooves using micro-computed tomography (CT). Eighty-eight mandibular second molars with fused roots were scanned in a micro-CT scanner at a voxel size of 19.6 μm. After reconstruction, only molars without C-shaped roots and presenting shallow radicular grooves were selected. 30 molars were chosen for further analysis. Canal cross-sections were classified according to Fan's modified classification (C1, C2, C3, and C4) and morphometric parameters at the apical region, examination of accessory foramina and tridimensional configuration were evaluated. Three-dimensional reconstructions indicated a higher prevalence of merging type ( n = 22). According to Fan's modified classification, the C4 configuration was predominant in the 3 apical mm. Roundness median values revealed a more round-shaped canals at 3 mm (0.72) than at 2 (0.63) and 1 (0.61) mm from the apex. High values of major and minor diameters were observed in the canals of these evaluated sections. In addition, few accessory apical foramina were observed at 1 and 2 mm from the apex. The average distance between last accessory foramina and the anatomic apex was 1.17 mm. A less complex internal anatomy is found when a mandibular second molar presents fused roots with shallow radicular grooves. The merging type canal was frequently observed. Moreover, the C4 configuration was predominant at a point 3 mm from the apex and presented rounded canals, large apical diameters, and few accessory foramina. The cervical and middle thirds presented C3 and C1 canal configurations most frequently. A minor morphological complexity is found when fused mandibular second molars present shallow radicular grooves.

Multipacting in a grooved choke joint at SRF gun for BNL ERL prototype

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

Xu, W.; Ben-Zvi, I.; Belomestnykh, S.

2011-03-28

The 703 MHz superconducting gun for BNL ERL prototype was tested at JLab with and without choke-joint and cathode stalk. Without choke-joint and cathode stalk, the gradient reached was 25 MV/m with Q{sup 0} {approx} 6E9. The gun cathode insertion port is equipped with a grooved choke joint for multipacting suppression. We carried out tests with choke-joint and cathode stalk. The test results show that there are at least two barriers at about 3.5 MV/m and 5 MV/m. We considered several possibilities and finally found that fine details of the grooved shape are important for multipacting suppression. A triangular groovemore » with round crest may cause strong multipacting in the choke-joint at 3.5 MV/m, 5 MV/m and 10 MV/m. This paper presents the primary test results of the gun and discusses the multipacting analysis in the choke-joint. It also suggests possible solutions for the gun and multipacting suppressing for a similar structure.« less

Minor groove binding of a bis-quaternary ammonium compound: the crystal structure of SN 7167 bound to d(CGCGAATTCGCG)2.

PubMed Central

Squire, C J; Clark, G R; Denny, W A

1997-01-01

The X-ray crystal structure of the complex between the synthetic antitumour and antiviral DNA binding ligand SN 7167 and the DNA oligonucleotide d(CGCGAATTCGCG)2 has been determined to an R factor of 18.3% at 2.6 A resolution. The ligand is located within the minor groove and covers almost 6 bp with the 1-methylpyridinium ring extending as far as the C9-G16 base pair and the 1-methylquinolinium ring lying between the G4-C21 and A5-T20 base pairs. The ligand interacts only weakly with the DNA, as evidenced by long range contacts and shallow penetration into the groove. This structure is compared with that of the complex between the parent compound SN 6999 and the alkylated DNA sequence d(CGC[e6G]AATTCGCG)2. There are significant differences between the two structures in the extent of DNA bending, ligand conformation and groove binding. PMID:9321660

The method for measuring the groove density of variable-line-space gratings with elimination of the eccentricity effect

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

Wang, Qingbo; Liu, Zhengkun, E-mail: zhkliu@ustc.edu.cn; Chen, Huoyao

2015-02-15

To eliminate the eccentricity effect, a new method for measuring the groove density of a variable-line-space grating was adapted. Based on grating equation, groove density is calculated by measuring the internal angles between zeroth-order and first-order diffracted light for two different wavelengths with the same angle of incidence. The measurement system mainly includes two laser sources, a phase plate, plane mirror, and charge coupled device. The measurement results of a variable-line-space grating demonstrate that the experiment data agree well with theoretical values, and the value of measurement error (ΔN/N) is less than 2.72 × 10{sup −4}.

Finding the Groove: A Grounded Theory Study on Leading Others to a Productive Path

ERIC Educational Resources Information Center

Williams, Roshann Reed

2011-01-01

Finding the groove was systematically discovered directly from data following the classical grounded theory methodology developed by Glaser and Strauss (1967) and further developed by Glaser (1965, 1978, 1992, 1998, 2001). This basic social process emerged from data as the pattern of behavior that leaders proceed through to increase performer…

DOUBLE-PEAKED NARROW-LINE ACTIVE GALACTIC NUCLEI. II. THE CASE OF EQUAL PEAKS

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

Smith, K. L.; Shields, G. A.; Salviander, S.

Active galactic nuclei (AGNs) with double-peaked narrow lines (DPAGNs) may be caused by kiloparsec-scale binary AGNs, bipolar outflows, or rotating gaseous disks. We examine the class of DPAGNs in which the two narrow-line components have closely similar intensity as being especially likely to involve disks or jets. Two spectroscopic indicators support this likelihood. For DPAGNs from Smith et al., the 'equal-peaked' objects (EPAGNs) have [Ne V]/[O III]ratios lower than for a control sample of non-double-peaked AGNs. This is unexpected for a pair of normal AGNs in a galactic merger, but may be consistent with [O III] emission from a rotatingmore » ring with relatively little gas at small radii. Also, [O III]/H{beta} ratios of the redshifted and blueshifted systems in the EPAGN are more similar to each other than in a control sample, suggestive of a single ionizing source and inconsistent with the binary interpretation.« less

Olfactory Groove Meningiomas: Comparison of Extent of Frontal Lobe Changes After Lateral and Bifrontal Approaches.

PubMed

Nanda, Anil; Maiti, Tanmoy K; Bir, Shyamal C; Konar, Subhas K; Guthikonda, Bharat

2016-10-01

Olfactory groove meningiomas often are behaviorally silent. Numerous surgical approaches have been described in the literature for the successful removal of these meningiomas. Lateral (pterional/frontolateral) and anterior (bifrontal/fronto-orbito-basal) approaches with their various modifications remain the 2 major corridors in resecting them. In this study, we discuss our experience in microsurgical treatment of these tumors at our institution and assess the extent of frontal lobe damage after the resection of tumor. We reviewed the medical records of patients who underwent surgical excision of olfactory groove meningiomas from 1990 to 2014. To measure the extent of frontal lobe damage via lateral and anterior approaches, we measured the volume of porencephalic cave in the postoperative magnetic resonance imaging by using Brainlab software. The ratio of volume of porencephalic cave to tumor was measured between 2 sides and 2 approaches. Fifty-seven patients with olfactory groove meningiomas, who underwent 62 microsurgical resection procedures in 1990-2014 were included in the study (74% were more than 5 cm at presentation). Pterional and bifrontal craniotomies were the most commonly used approaches. At follow-up, the volume of porencephalic cave after lateral approach was significantly less in the side contralateral to craniotomy irrespective of tumor size. The difference between ratio of volume of porencephalic cave and initial tumor was significantly less after lateral approaches, when compared to anterior approaches. Lateral approaches (pterional/frontolateral) resulted in less frontal lobe change and better olfactory preservation in comparison to anterior approaches in present series. Published by Elsevier Inc.

Visible and Near-Infrared Spectroscopy of Seyfert 1 and Narrow-Line Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Rodríguez-Ardila, Alberto; Pastoriza, Miriani G.; Donzelli, Carlos J.

2000-01-01

This paper studies the continuum and emission-line properties of a sample composed of 16 normal Seyfert 1 and seven narrow-line Seyfert 1 (NLS1) galaxies using optical and near-IR CCD spectroscopy. The continuum emission of the galaxies can be described in terms of a combination of stellar population, a nonstellar continuum of power-law form, and Fe II emission. A significative difference in the optical spectral index between NLS1's and normal Seyfert 1's is observed; the latter is steeper. Most NLS1's show Fe II/Hβ ratios larger than those observed in the other Seyfert 1's. In the IRAS band, both groups of galaxies have very similar properties. We have searched for the presence of optically thin gas in the broad-line region (BLR) of the galaxies by comparing the broad O I λ8446 and Hα emission-line profiles. Our analysis show that in the NLS1's, both profiles are similar in shape and width. This result contradicts the hypothesis of thin gas emission in the high-velocity part of the BLR to explain the ``narrowness'' of broad optical permitted lines in these objects. Evidence of narrow O I λ8446 emission is found in six galaxies of our sample, implying that this line is not restricted to a pure BLR phenomenon. In the narrow-line region, we find similar luminosities in the permitted and high-ionization lines of NLS1's and normal Seyfert 1's. However, low-ionization lines such as [O I] λ6300, [O II] λ3727, and [S II] λλ6717, 6731 are intrinsically less luminous in NLS1's. Physical properties derived from density- and temperature-sensitive line ratios suggest that the [O II] and [S II] emitting zones are overlapping in normal Seyfert 1's and separated in NLS1's. Based on observations made at CASLEO. Complejo Astronómico El Leoncito (CASLEO) is operated under agreement between the Consejo Nacional de Investigaciones Científicas y técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juán.

INJURIES OF THE SAGITTAL GROOVE OF THE PROXIMAL PHALANX IN WARMBLOOD HORSES DETECTED WITH LOW-FIELD MAGNETIC RESONANCE IMAGING: 19 CASES (2007-2016).

PubMed

Gold, Sarah J; Werpy, Natasha M; Gutierrez-Nibeyro, Santiago D

2017-05-01

Sagittal groove injuries of the proximal phalanx are an important cause of lameness in performance horses. The purpose of this retrospective case series study was to describe standing low-field magnetic resonance imaging (MRI) characteristics of these injuries in a group of Warmblood horses. Horses with an MRI diagnosis of sagittal groove injuries involving the proximal phalanx and that had follow-up MRI and clinical outcome information were included. Findings from clinical examinations, diagnostic tests, and other imaging modalities were recorded. All MRI studies were retrieved for re-evaluation by an experienced, board-certified veterinary radiologist. A total of 19 horses met inclusion criteria. All horses had MRI lesions consistent with unilateral or bilateral sagittal groove injuries of the proximal phalanx and abnormal mineralization of the sagittal ridge of the third metacarpal/metatarsal bone. Fifteen horses (79%) had concurrent osteoarthritis of the affected metacarpophalangeal/metatarsophalangeal joint. Eighteen horses received conservative therapy and all horses still had osseous abnormalities detected at the time of follow-up MRI. Thirteen horses (68.5%) were still lame at the time of follow-up, whereas the other six horses (31.5%) had become sound and returned to the previous level of exercise. Findings indicated that, for mature Warmblood horses, acute or chronic injuries of the sagittal groove of the proximal phalanx may have variable standing low-field MRI characteristics. Based on this sample of 19 horses, findings also indicated that the prognosis for performance soundness in horses diagnosed with sagittal groove injury of the proximal phalanx and concurrent osteoarthritis is poor. © 2017 American College of Veterinary Radiology.

Groove micro-structure optical fiber refractive index sensor with nanoscale gold film based on surface plasmon resonance

NASA Astrophysics Data System (ADS)

Zhang, Zhen; Li, Shuguang; Liu, Qiang; Feng, Xinxing; Zhang, Shuhuan; Wang, Yujun; Wu, Junjun

2018-07-01

A groove micro-structure optical fiber refractive index sensor with nanoscale gold film based on surface plasmon resonance (SPR) is proposed and analyzed by the finite element method (FEM). Numerical results show that the average sensitivity is 15,933 nm/refractive index unit (RIU) with the refractive index of analyte ranging from 1.40 to 1.43 and the maximum sensitivity is 28,600 nm/RIU and the resolution of the sensor is 3.50 × 10-8 RIU. The groove micro-structure optical fiber refractive index sensor do some changes on the D-shaped fiber sensor, compared with conventional D-shaped fiber sensor, it has a higher sensitivity and it is easier to produce than the traditional SPR sensor.

Study on airflow characteristics in the semi-closed irregular narrow flow channel

NASA Astrophysics Data System (ADS)

Jin, Yuzhen; Hu, Xiaodong; Zhu, Linhang; Hu, Xudong; Jin, Yingzi

2016-04-01

The air-jet loom is widely used in the textile industry. The interaction mechanism of airflow and yarn is not clear in such a narrow flow channel, the gas consumption is relatively large, the yarn motion is unstable and the weft insertion is often interrupted during the operation. In order to study the characteristics of the semi-closed flow field in profiled dents, the momentum conservation equation is modified and the model parameters and boundary conditions are set. Compared with the different r, the ratio of profiled dent's thickness and gap, the results show that the smaller the r is, the smaller the velocity fluctuations of the airflow is. When the angle of profiled dents α is close to zero, the diffusion of the airflow will be less. The experiment is also conducted to verify the result of the simulation with a high-speed camera and pressure sensor in profiled dents. The airflow characteristics in the semi-closed irregular narrow flow channel in the paper would provide the theoretical basis for optimizing the weft insertion process of the air-jet loom.

Galaxy Feeds Off Gas Artist Concept

NASA Image and Video Library

2011-09-13

In this artist conception based on data from ESA Herschel observatory, a galaxy accretes mass from rapid, narrow streams of cold gas. These filaments provide the galaxy with continuous flows of raw material to feed its star-forming at a leisurely pace

Narrow-headed garter snake (Thamnophis rufipunctatus)

USGS Publications Warehouse

Nowak, Erika M.

2006-01-01

The narrow-headed garter snake is a harmless, nonvenomous snake that is distinguished by its elongated, triangular-shaped head and the red or dark spots on its olive to tan body. Today, the narrow-headed garter snake is a species of special concern in the United States because of its decline over much of its historic range. Arizona's Oak Creek has historically contained the largest population of narrow-headed garter snakes in the United States. The U.S. Geological Survey (USGS) and the Arizona Game and Fish Department jointly funded research by USGS scientists in Oak Creek to shed light on the factors causing declining population numbers. The research resulted in better understanding of the snake's habitat needs, winter and summer range, and dietary habits. Based on the research findings, the U.S. Forest Service has developed recommendations that visitors and local residents can adopt to help slow the decline of the narrow-headed garter snake in Oak Creek.

Incremental Drag due to Grooves and Threads for KE (Kinetic Energy) Projectiles

DTIC Science & Technology

1989-03-01

RFI • CTsB TF * - MF (3a) q L where TF1 is the Thread Factor defined as: TF 0.84 + 0.117 P - o (3b) where p is the groove pitch in inches, MF1 is...g2) MF RF CD (4) where TF11 and TF1 2 are the thread factors for the threads of pitch p, and P2, respectively. 5 One can notice the large

Analysis and Design of a Double-Divert Spiral Groove Seal

NASA Technical Reports Server (NTRS)

Zheng, Xiaoqing; Berard, Gerald

2007-01-01

This viewgraph presentation describes the design and analysis of a double spiral groove seal. The contents include: 1) Double Spiral Design Features; 2) Double Spiral Operational Features; 3) Mating Ring/Rotor Assembly; 4) Seal Ring Assembly; 5) Insert Segment Joints; 6) Rotor Assembly Completed Prototype Parts; 7) Seal Assembly Completed Prototype Parts; 8) Finite Element Analysis; 9) Computational Fluid Dynamics (CFD) Analysis; 10) Restrictive Orifice Design; 11) Orifice CFD Model; 12) Orifice Results; 13) Restrictive Orifice; 14) Seal Face Coning; 15) Permanent Magnet Analysis; 16) Magnetic Repulsive Force; 17) Magnetic Repulsive Test Results; 18) Spin Testing; and 19) Testing and Validation.

Effect on Bone Architecture of Marginal Grooves in Dental Implants Under Occlusal Loaded Conditions in Beagle Dogs.

PubMed

Kato, Hatsumi; Kuroshima, Shinichiro; Inaba, Nao; Uto, Yusuke; Sawase, Takashi

2018-02-01

The aim of this study was to clarify whether marginal grooves on dental implants affect osseointegration, bone structure, and the alignment of collagen fibers to determine bone quality under loaded conditions. Anodized Ti-6Al-4V alloy dental implants, with and without marginal grooves (test and control implants, respectively), were used (3.7 × 8.0 mm). Fourth premolars and first molars of 6 beagle mandibles were extracted. Two control and test implants were placed in randomly selected healed sites at 12 weeks after tooth extraction. Screw-retained single crowns for first molars were fabricated. Euthanasia was performed at 8 weeks after the application of occlusal forces. Implant marginal bone level, bone to implant contact (BIC), bone structure around dental implants, and the alignment of collagen fibers determining bone quality were analyzed. The marginal bone level in test implants was significantly higher than that in control implants. Occlusal forces significantly increased BIC in test implants ( P = .007), whereas BIC did not change in control implants, irrespective of occlusal forces ( P = .303). Moreover, occlusal forces significantly increased BIC in test implants compared with control implants ( P = .032). Additionally, occlusal forces preferentially aligned collagen fibers in test implants, but not control implants. Hence, marginal grooves on dental implants have positive effects on increased osseointegration and adapted bone quality based on the preferential alignment of collagen fibers around dental implants under loaded conditions.

CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

NASA Astrophysics Data System (ADS)

Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa

2017-07-01

The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O III], [S II], and Hα, as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ˜10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include Hα evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.

Conventional and narrow bore short capillary columns with cyclodextrin derivatives as chiral selectors to speed-up enantioselective gas chromatography and enantioselective gas chromatography-mass spectrometry analyses.

PubMed

Bicchi, Carlo; Liberto, Erica; Cagliero, Cecilia; Cordero, Chiara; Sgorbini, Barbara; Rubiolo, Patrizia

2008-11-28

The analysis of complex real-world samples of vegetable origin requires rapid and accurate routine methods, enabling laboratories to increase sample throughput and productivity while reducing analysis costs. This study examines shortening enantioselective-GC (ES-GC) analysis time following the approaches used in fast GC. ES-GC separations are due to a weak enantiomer-CD host-guest interaction and the separation is thermodynamically driven and strongly influenced by temperature. As a consequence, fast temperature rates can interfere with enantiomeric discrimination; thus the use of short and/or narrow bore columns is a possible approach to speeding-up ES-GC analyses. The performance of ES-GC with a conventional inner diameter (I.D.) column (25 m length x 0.25 mm I.D., 0.15 microm and 0.25 microm d(f)) coated with 30% of 2,3-di-O-ethyl-6-O-tert-butyldimethylsilyl-beta-cyclodextrin in PS-086 is compared to those of conventional I.D. short column (5m length x 0.25 mm I.D., 0.15 microm d(f)) and of different length narrow bore columns (1, 2, 5 and 10 m long x 0.10 mm I.D., 0.10 microm d(f)) in analysing racemate standards of pesticides and in the flavour and fragrance field and real-world-samples. Short conventional I.D. columns gave shorter analysis time and comparable or lower resolutions with the racemate standards, depending mainly on analyte volatility. Narrow-bore columns were tested under different analysis conditions; they provided shorter analysis time and resolutions comparable to those of conventional I.D. ES columns. The narrow-bore columns offering the most effective compromise between separation efficiency and analysis time are the 5 and 2m columns; in combination with mass spectrometry as detector, applied to lavender and bergamot essential oil analyses, these reduced analysis time by a factor of at least three while separation of chiral markers remained unaltered.

Stackable multi-port gas nozzles

DOEpatents

Poppe, Steve; Rozenzon, Yan; Ding, Peijun

2015-03-03

One embodiment provides a reactor for material deposition. The reactor includes a chamber and at least one gas nozzle. The chamber includes a pair of susceptors, each having a front side and a back side. The front side mounts a number of substrates. The susceptors are positioned vertically so that the front sides of the susceptors face each other, and the vertical edges of the susceptors are in contact with each other, thereby forming a substantially enclosed narrow channel between the substrates mounted on different susceptors. The gas nozzle includes a gas-inlet component situated in the center and a detachable gas-outlet component stacked around the gas-inlet component. The gas-inlet component includes at least one opening coupled to the chamber, and is configured to inject precursor gases into the chamber. The detachable gas-outlet component includes at least one opening coupled to the chamber, and is configured to output exhaust gases from the chamber.

Into the groove: instructive silk-polypyrrole films with topographical guidance cues direct DRG neurite outgrowth.

PubMed

Hardy, John G; Khaing, Zin Z; Xin, Shangjing; Tien, Lee W; Ghezzi, Chiara E; Mouser, David J; Sukhavasi, Rushi C; Preda, Rucsanda C; Gil, Eun S; Kaplan, David L; Schmidt, Christine E

2015-01-01

Instructive biomaterials capable of controlling the behaviour of the cells are particularly interesting scaffolds for tissue engineering and regenerative medicine. Novel biomaterials are particularly important in societies with rapidly aging populations, where demand for organ/tissue donations is greater than their supply. Herein we describe the preparation of electrically conductive silk film-based nerve tissue scaffolds that are manufactured using all aqueous processing. Aqueous solutions of Bombyx mori silk were cast on flexible polydimethylsiloxane substrates with micrometer-scale grooves on their surfaces, allowed to dry, and annealed to impart β-sheets to the silk which assures that the materials are stable for further processing in water. The silk films were rendered conductive by generating an interpenetrating network of polypyrrole and polystyrenesulfonate in the silk matrix. Films were incubated in an aqueous solution of pyrrole (monomer), polystyrenesulfonate (dopant) and iron chloride (initiator), after which they were thoroughly washed to remove low molecular weight components (monomers, initiators, and oligomers) and dried, yielding conductive films with sheet resistances of 124 ± 23 kΩ square(-1). The micrometer-scale grooves that are present on the surface of the films are analogous to the natural topography in the extracellular matrix of various tissues (bone, muscle, nerve, skin) to which cells respond. Dorsal root ganglions (DRG) adhere to the films and the grooves in the surface of the films instruct the aligned growth of processes extending from the DRG. Such materials potentially enable the electrical stimulation (ES) of cells cultured on them, and future in vitro studies will focus on understanding the interplay between electrical and topographical cues on the behaviour of cells cultured on them.

Spatially Resolved Spectroscopy of Narrow-line Seyfert 1 Host Galaxies

NASA Astrophysics Data System (ADS)

Scharwächter, J.; Husemann, B.; Busch, G.; Komossa, S.; Dopita, M. A.

2017-10-01

We present optical integral field spectroscopy for five z< 0.062 narrow-line Seyfert 1 (NLS1) galaxies, probing their host galaxies at ≳ 2{--}3 {kpc} scales. Emission lines from the active galactic nucleus (AGN) and the large-scale host galaxy are analyzed separately, based on an AGN-host decomposition technique. The host galaxy gas kinematics indicates large-scale gas rotation in all five sources. At the probed scales of ≳ 2{--}3 {kpc}, the host galaxy gas is found to be predominantly ionized by star formation without any evidence of a strong AGN contribution. None of the five objects shows specific star formation rates (SFRs) exceeding the main sequence of low-redshift star-forming galaxies. The specific SFRs for MCG-05-01-013 and WPVS 007 are roughly consistent with the main sequence, while ESO 399-IG20, MS 22549-3712, and TON S180 show lower specific SFRs, intermediate to the main sequence and the red quiescent galaxies. The host galaxy metallicities, derived for the two sources with sufficient data quality (ESO 399-IG20 and MCG-05-01-013), indicate central oxygen abundances just below the low-redshift mass-metallicity relation. Based on this initial case study, we outline a comparison of AGN and host galaxy parameters as a starting point for future extended NLS1 studies with similar methods.

Do size, shape, and alignment parameters of the femoral condyle affect the trochlear groove tracking? A morphometric study based on 3D- computed tomography models in Chinese people.

PubMed

Du, Zhe; Chen, Shichang; Yan, Mengning; Yue, Bing; Zeng, Yiming; Wang, You

2017-01-06

Our study aimed to investigate whether geometrical features (size, shape, or alignment parameters) of the femoral condyle affect the morphology of the trochlear groove. Computed tomography models of 195 femurs (97 and 98 knees from male and female subjects, respectively) were reconstructed into three-dimensional models and categorised into four types of trochlear groove morphology based on the position of the turning point in relation to the mechanical axis (types 45°, 60°, 75°, and 90°). Only subjects with healthy knees were included, whereas individuals with previous knee trauma or knee pain, soft tissue injury, osteoarthritis, or other chronic diseases of the musculoskeletal system were excluded. The size parameters were: radius of the best-fit cylinder, anteroposterior dimension of the lateral condyles (AP), and distal mediolateral dimension (ML). The shape parameters were: aspect ratio (AP/ML), arc angle, and proximal- and distal- end angles. The alignment parameters were: knee valgus physiologic angle (KVPA), mechanical medial distal femoral angle (mMDFA), and hip-knee-ankle angle (HKA). All variables were measured in the femoral condyle models, and the means for each groove type were compared using one-way analysis of variance. No significant difference among groove types was observed regarding size parameters. There were significant differences when comparing type 45° with types 60°, 75°, and 90° regarding aspect ratio and distal-end angle (p < 0.05), but not regarding proximal-end angle. There were significant differences when comparing type 90° with types 45°, 60°, and 75° regarding KVPA, mMDFA, and HKA (p < 0.05). Among size, shape, and alignment parameters, the latter two exhibited partial influence on the morphology of the trochlear groove. Shape parameters affected the trochlear groove for trochlear type 45°, for which the femoral condyle was relatively flat, whereas alignment parameters affected the trochlear groove for trochlear

Friction characteristics of three 30 by 11.5-14.5, type 8, aircraft tires with various tread groove patterns and rubber compounds

NASA Technical Reports Server (NTRS)

Yager, T. J.; Mccarty, J. L.

1977-01-01

A test program was conducted to evaluate friction performance and wear characteristics on wet runways of three 30 x 11.5-14.5, type, aircraft tires having two different tread patterns and natural rubber contents. All test tires had the standard three circumferential groove tread, but two had molded transverse grooves which extended from shoulder to shoulder. The tread rubber content of the two tires with transverse grooves differed in that one had a 100 percent natural rubber tread and the other had a rubber tread composition that was 30 percent synthetic and 70 percent natural. The third test tire had the conventional 100 percent natural rubber tread. Results indicate that the differences in tire tread design and rubber composition do not significantly affect braking and cornering friction capability on wet or dry surfaces. Braking performance of the tires decreases with increased speed, with increased yaw angle and, at higher speeds, with increased wetness of the surface.

Increased viscosity of hemoglobin-based oxygen carriers retards NO-binding when perfused through narrow gas-permeable tubes.

PubMed

Sakai, Hiromi; Okuda, Naoto; Takeoka, Shinji; Tsuchida, Eishun

2011-03-01

Increased fluid viscosity of a solution of hemoglobin-based oxygen carriers (HBOCs) reduces vasoconstrictive effects because increased shear stress on the vascular wall enhances the production of vasorelaxation factors such as NO. Nevertheless, on a microcirculatory level, it remains unclear how viscosity affects the reaction of HBOCs and NO. In this study, different HBOCs were perfused through narrow gas-permeable tubes (25 μm inner diameter at 1 mm/s centerline velocity; hemoglobin concentration [Hb]=5 g/dL). The reaction was examined microscopically based on the Hb visible-light absorption spectrum. When immersed in a NO atmosphere, the NO-binding of deoxygenated Hb solution (viscosity, 1.1 cP at 1000 s(-1)) in the tube occurred about twice as rapidly as that of red blood cells (RBCs): 1.6 cP. Binding was reduced by PEGylation (PEG-Hb, 7.7 cP), by addition of a high molecular weight hydroxyethyl starch (HES) (2.8 cP), and by encapsulation to form Hb-vesicles (HbVs, 1.5 cP; particle size 279 nm). However, the reduction was not as great as that shown for RBCs. A mixture of HbVs and HES (6.2 cP) showed almost identical NO-binding to that of RBCs. Higher viscosity and particle size might reduce lateral diffusion when particles are flowing. The HbVs with HES showed the slowest NO-binding. Furthermore, Hb encapsulation and PEGylation, but not HES-addition, tended to retard CO-binding. Increased viscosity reportedly enhances production of endothelium NO. In addition, our results show that the increased viscosity also inhibits the reaction with NO. Each effect might mitigate vasoconstriction. Copyright © 2010 Elsevier Inc. All rights reserved.

DNA Replication Arrest and DNA Damage Responses Induced by Alkylating Minor Groove Binders

DTIC Science & Technology

2003-05-01

Alkylating minor groove DNA binder adozelesin is capable of inhibiting DNA replication in treated cells through a trans-acting mechanism. The trans... replication in vitro. Using purified proteins in DNA replication initiation assays, we found that RPA purified from cells treated with adozelesin in not...adozelesin has the same single-stranded DNA binding activity and support nucleotide excision repair as normal RPA, but is not able to support SV40 DNA

A comparative study of ethylene oxide gas, hydrogen peroxide gas plasma, and low-temperature steam formaldehyde sterilization.

PubMed

Kanemitsu, Keiji; Imasaka, Takayuki; Ishikawa, Shiho; Kunishima, Hiroyuki; Harigae, Hideo; Ueno, Kumi; Takemura, Hiromu; Hirayama, Yoshihiro; Kaku, Mitsuo

2005-05-01

To compare the efficacies of ethylene oxide gas (EOG), hydrogen peroxide gas plasma (PLASMA), and low-temperature steam formaldehyde (LTSF) sterilization methods. The efficacies of EOG, PLASMA, and LTSF sterilization were tested using metal and plastic plates, common medical instruments, and three process challenge devices with narrow lumens. All items were contaminated with Bacillus stearothermophilus spores or used a standard biological indicator. EOG and LTSF demonstrated effective killing of B. stearothermophilus spores, with or without serum, on plates, on instruments, and in process challenge devices. PLASMA failed to adequately sterilize materials on multiple trials in several experiments, including two of three plates, two of three instruments, and all process challenge devices. Our results suggest that PLASMA sterilization may be unsuccessful under certain conditions, particularly when used for items with complex shapes and narrow lumens. Alternatively, LTSF sterilization demonstrates excellent efficacy and is comparable to EOG sterilization. LTSF could potentially act as a substitute if EOG becomes unavailable due to environmental concerns.

A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

NASA Astrophysics Data System (ADS)

Cracco, V.; Ciroi, S.; Berton, M.; Di Mille, F.; Foschini, L.; La Mura, G.; Rafanelli, P.

2016-10-01

We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole masses and higher Eddington ratios than classic broad-line Seyfert 1 (BLS1s), but they also appear to be active galactic nuclei (AGNs) contiguous with BLS1s and sharing with them common properties. Strong Fe II emission does not seem to be a distinctive property of NLS1s, as low values of Fe II/Hβ are equally observed in these AGNs. Our data indicate that Fe II and Ca II kinematics are consistent with the one of Hβ. On the contrary, O I λ8446 seems to be systematically narrower and it is likely emitted by gas of the broad-line region more distant from the ionizing source and showing different physical properties. Finally, almost all NLS1s of our sample show radial motions of the narrow-line region highly ionized gas. The mechanism responsible for this effect is not yet clear, but there are hints that very fast outflows require high continuum luminosities (>1044 erg s-1) or high Eddington ratios (log (Lbol/LEdd) > -0.1).

The Tongue-in-Groove Technique in Primary and Revision Rhinoplasty.

PubMed

Datema, Frank R; Lohuis, Peter J F M

2016-08-01

The tongue-in-groove (TIG) is a conservative but powerful surgical suture technique to control tip rotation and projection, to set an appropriate alar-columellar relationship, to straighten a caudal septal deviation, and to stabilize the nasal base. TIG is suitable in primary and most revision cases and is easily combined with other surgical techniques. Seventeen years after its popularization, the TIG technique is embedded in modern-day rhinoplasty literature and teaching material. This article describes indications and considerations during external primary and revision rhinoplasty, based on clinical experience and the available literature. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Narrow Networks on the Individual Marketplace in 2017.

PubMed

Polski, Daniel; Weiner, Janet; Zhang, Yuehan

2017-09-01

This Issue Brief describes the breadth of physician networks on the ACA marketplaces in 2017. We find that the overall rate of narrow networks is 21%, which is a decline since 2014 (31%) and 2016 (25%). Narrow networks are concentrated in plans sold on state-based marketplaces, at 42%, compared to 10% of plans on federally-facilitated marketplaces. Issuers that have traditionally offered Medicaid coverage have the highest prevalence of narrow network plans at 36%, with regional/local plans and provider-based plans close behind at 27% and 30%. We also find large differences in narrow networks by state and by plan type.

Artificial neural network modeling of a deflector in a grooved channel as well as optimization of its effective parameters

NASA Astrophysics Data System (ADS)

Abdollahi, Azita; Shams, Mehrzad; Abdollahi, Anita

2018-01-01

One of methods available to increase the rate of heat transfer in channels with parallel plates is making grooves in them. But, the fundamental problem of this method is the formation of stagnation zone in the grooves and as a result formation a zone with low energy transfer. In this paper, the effect of placing curved deflectors (geometries with elliptical forms) in channel on thermal and hydraulic characteristic of the fluid flow- with the aim of directing of the flow into the grooves and as a result increasing the rate of heat transfer in this zone- are investigated and heat transfer coefficient and pressure drop are calculated for different values of Reynolds number and geometrical parameters of the deflector (its small and large radiuses). The results show that the presence of the deflector in the channel significantly increases the heat transfer rate compare to the channel without deflector. Of course, it should be noted that this work also increases the pressure drop. So, finally in order to determine configurations of the deflector causing minimum pressure drop, maximum Nusselt number or a balance between them, optimization algorithm consisting of artificial neural network and multi-objective genetic algorithm was utilized to calculate the optimal values of these parameters.

Investigation of a Tricarbide Grooved Ring Fuel Element for a Nuclear Thermal Rocket

NASA Technical Reports Server (NTRS)

Taylor, Brian D.; Emrich, Bill; Tucker, Dennis; Barnes, Marvin; Donders, Nicolas; Benensky, Kelsa

2017-01-01

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nuclear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the temperature limitations of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment.

Polarization-independent triangular-groove fused-silica gratings with high efficiency at a wavelength of 1550 nm

NASA Astrophysics Data System (ADS)

Cao, Hongchao; Zhou, Changhe; Feng, Jijun; Lv, Peng; Ma, Jianyong

2010-11-01

We describe polarization-independent triangular-groove fused-silica gratings illuminated by incident lights in the C + L bands as (de)multiplexers for dense wavelength division multiplexing (DWDM) application. The physical mechanisms of the grating can be shown clearly by using the simplified modal method with consideration of the corresponding accumulated average phase difference of two excited propagating grating modes, which illustrates that the grating structure depends mainly on the ratio of the average effective indices difference to the incident wavelength. Exact grating profile is optimized by using the rigorous coupled-wave analysis (RCWA). With the optimized grating parameters, the grating exhibits diffraction efficiencies of greater than 90% under TE- and TM-polarized incident lights for 101 nm spectral bandwidths (1500-1601 nm) and it can reach an efficiency of more than 99% for both polarizations at a wavelength of 1550 nm. Without loss of metal absorption, coating of dielectric film layers, the designed triangular-groove fused-silica grating should be of great interest for DWDM application.

Modern Microsurgical Resection of Olfactory Groove Meningiomas by Classical Bicoronal Subfrontal Approach without Orbital Osteotomies

PubMed Central

Farooq, Ghulam; Rehman, Lal; Bokhari, Irum; Rizvi, Syed Raza Hussain

2018-01-01

Background: The olfactory groove meningioma has always been surgically challenging. The common microscopic surgical procedures exercised involve modification of pterional or sub-frontal approaches with or without orbital osteotomies. However, we believe that orbital osteotomies are not mandatory to achieve gross total resection. Hence, this study was performed to evaluate the surgical outcomes of olfactory groove meningioma with bicoronal sub frontal approach but without orbital osteotomies. Materials and Methods: The study was performed by reviewing the medical charts, neuroimaging data, and follow-up data of 19 patients who were treated micro surgically for olfactory groove meningioma without orbital osteotomies in our department. Mean overall follow up period of our study was 5 years. Statistical analysis was done by means of IBM SPSS Software version 19. Results: Nineteen patients (1 male and 18 female patients, with an age range of 35-67 years; average age of patients' 51±7.5 years) of OGM were managed in our department. All patients were evaluated by MRI Brain with and without Gadolinium, CTA, CT Scan both axial and Coronal sequences. Most common symptom reported was head ache (80%), others include; urinary incontinence (26%), seizures (78%), decreased visual acuity (79%), papilledema (74%), personality changes (68%) and olfactory loss was reported in 57% of the patients. Post-operative complications include; CSF accumulation (5%), hematoma at tumor bed (10%), skin infection (5%) and mild post-operative brain edema (26%). Mortality rate was 5%. During 5 years of follow-up, we recorded one recurrence which was after 26 months and successfully removed in reoperation. Conclusion: Bi-coronal sub frontal approach appears to be an excellent technique for Olfactory Meningioma removal as practiced by most neurosurgeons. Nevertheless, it is not mandatory to carry out orbital osteotomy to acquire optimal surgical outcome as is advocated by some Authors. PMID:29682018

Modern Microsurgical Resection of Olfactory Groove Meningiomas by Classical Bicoronal Subfrontal Approach without Orbital Osteotomies.

PubMed

Farooq, Ghulam; Rehman, Lal; Bokhari, Irum; Rizvi, Syed Raza Hussain

2018-01-01

The olfactory groove meningioma has always been surgically challenging. The common microscopic surgical procedures exercised involve modification of pterional or sub-frontal approaches with or without orbital osteotomies. However, we believe that orbital osteotomies are not mandatory to achieve gross total resection. Hence, this study was performed to evaluate the surgical outcomes of olfactory groove meningioma with bicoronal sub frontal approach but without orbital osteotomies. The study was performed by reviewing the medical charts, neuroimaging data, and follow-up data of 19 patients who were treated micro surgically for olfactory groove meningioma without orbital osteotomies in our department. Mean overall follow up period of our study was 5 years. Statistical analysis was done by means of IBM SPSS Software version 19. Nineteen patients (1 male and 18 female patients, with an age range of 35-67 years; average age of patients' 51±7.5 years) of OGM were managed in our department. All patients were evaluated by MRI Brain with and without Gadolinium, CTA, CT Scan both axial and Coronal sequences. Most common symptom reported was head ache (80%), others include; urinary incontinence (26%), seizures (78%), decreased visual acuity (79%), papilledema (74%), personality changes (68%) and olfactory loss was reported in 57% of the patients. Post-operative complications include; CSF accumulation (5%), hematoma at tumor bed (10%), skin infection (5%) and mild post-operative brain edema (26%). Mortality rate was 5%. During 5 years of follow-up, we recorded one recurrence which was after 26 months and successfully removed in reoperation. Bi-coronal sub frontal approach appears to be an excellent technique for Olfactory Meningioma removal as practiced by most neurosurgeons. Nevertheless, it is not mandatory to carry out orbital osteotomy to acquire optimal surgical outcome as is advocated by some Authors.

SSME seal test program: Test results for smooth, hole-pattern and helically-grooved stators

NASA Technical Reports Server (NTRS)

Childs, Dara W.

1987-01-01

All of the listed seals were tested in a liquid Halon test facility at high Reynolds numbers. In addition, a helically-grooved-stator seal was tested in an air seal facility. An analysis of the test results with comparisons to theoretical predictions supports the following conclusions: (1) For small seals, the Hirs' friction-factor model is more restricted than had been thought; (2) For smooth seals, predictions of stiffness and damping improve markedly as the radical clearance is reduced; (3) Friction-factor data for hole-pattern-seal stators frequently deviates from the Hirs model; (4) Predictions of stiffness and damping coefficients for hole-pattern-stator seals is generally reasonable; (5) Tests for the hole-pattern stators at reduced clearances show no clear optimum for hole-pattern seals with respect to either hole-area ratio or hole depth to minimum clearance ratios; (6) Tests of these hole-pattern stators show no significant advantage in net damping over smooth seals; (7) Tests of helically-grooved seal stators in Halon show reasonable agreement between theory and prediction for leakage and direct stiffness but poor agreement for the net damping coefficient.

Grooves to tubes: evolution of the venom delivery system in a Late Triassic "reptile"

NASA Astrophysics Data System (ADS)

Mitchell, Jonathan S.; Heckert, Andrew B.; Sues, Hans-Dieter

2010-12-01

Venom delivery systems occur in a wide range of extant and fossil vertebrates and are primarily based on oral adaptations. Teeth range from unmodified (Komodo dragons) to highly specialized fangs similar to hypodermic needles (protero- and solenoglyphous snakes). Developmental biologists have documented evidence for an infolding pathway of fang evolution, where the groove folds over to create the more derived condition. However, the oldest known members of venomous clades retain the same condition as their extant relatives, resulting in no fossil evidence for the transition. Based on a comparison of previously known specimens with newly discovered teeth from North Carolina, we describe a new species of the Late Triassic archosauriform Uatchitodon and provide detailed analyses that provide evidence for both venom conduction and document a complete structural series from shallow grooves to fully enclosed tubular canals. While known only from teeth, Uatchitodon is highly diagnostic in possessing compound serrations and for having two venom canals on each tooth in the dentition. Further, although not a snake, Uatchitodon sheds light on the evolutionary trajectory of venom delivery systems in amniotes and provide solid evidence for venom conduction in archosaur-line diapsids.

CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

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

Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin

The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc)more » across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.« less

A statistical study of H i gas in nearby narrow-line AGN-hosting galaxies

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

Zhu, Yi-Nan; Wu, Hong, E-mail: zyn@bao.ac.cn, E-mail: hwu@bao.ac.cn

As a quenching mechanism, active galactic nucleus (AGN) feedback could suppress on going star formation in host galaxies. On the basis of a sample of galaxies selected from the Arecibo Legacy Fast ALFA (ALFALFA) H i survey, the dependence of the H i mass (M{sub H} {sub i}), stellar mass (M{sub *}), and H i-to-stellar mass ratio (M{sub H} {sub i}/M{sub *}) on various tracers of AGN activity are presented and analyzed in this paper. Almost all the AGN hostings in this sample are gas-rich galaxies, and there is not any evidence to indicate that the AGN activity could increasemore » or decrease either M{sub H} {sub i} or M{sub H} {sub i}/M{sub *}. The position of the cold neutral gas cannot be fixed accurately based only on available H i data, due to the large beam size of ALFALFA survey. In addition, even though AGN hostings are more easily detected by an H i survey compared with absorption line galaxies, these two types of galaxies show similar star formation history. If an AGN hosting would ultimately evolve into an old red galaxy with low cold gas, then when and how the gas has been exhausted must be solved by future hypotheses and observations.« less

Planar spoof plasmonic ultra-wideband filter based on low-loss and compact terahertz waveguide corrugated with dumbbell grooves.

PubMed

Zhou, Yong Jin; Yang, Bao Jia

2015-05-10

Although subwavelength planar terahertz (THz) plasmonic devices can be implemented based on planar spoof surface plasmons (SPs), they still suffer from a little high propagation loss. Here the dispersion and propagation characteristics of the spoof plasmonic waveguide composed of double metal strips corrugated with dumbbell shaped grooves have been investigated. It has been found that much lower propagation loss and longer propagation length can be achieved based on the waveguide compared with the conventional spoof plasmonic waveguide with rectangular grooves. Moreover, the waveguide can implement a decrease in size of about 22%. An ultra-wideband THz plasmonic filter for planar circuits has been demonstrated based on the proposed waveguide. The experimental verification at the microwave frequency has been conducted by scaling up the geometry size of the filter.

An analysis of tire tread wear groove patterns and the effect of heteroscedasticity on tire tread wear statistics

DOT National Transportation Integrated Search

1985-09-01

This report examines the groove wear variability among tires subjected to the : Uniform Tire Quality Grading (UTQC) test procedure for determining tire tread wear. : The effects of heteroscedasticity (variable variance) on a previously reported : sta...

Dance, Music, Meter and Groove: A Forgotten Partnership

PubMed Central

Fitch, W. Tecumseh

2016-01-01

I argue that core aspects of musical rhythm, especially “groove” and syncopation, can only be fully understood in the context of their origins in the participatory social experience of dance. Musical meter is first considered in the context of bodily movement. I then offer an interpretation of the pervasive but somewhat puzzling phenomenon of syncopation in terms of acoustic emphasis on certain offbeat components of the accompanying dance style. The reasons for the historical tendency of many musical styles to divorce themselves from their dance-based roots are also briefly considered. To the extent that musical rhythms only make sense in the context of bodily movement, researchers interested in ecologically valid approaches to music cognition should make a more concerted effort to extend their analyses to dance, particularly if we hope to understand the cognitive constraints underlying rhythmic aspects of music like meter and groove. PMID:26973489

Ring resonator based narrow-linewidth semiconductor lasers

NASA Technical Reports Server (NTRS)

Ksendzov, Alexander (Inventor)

2005-01-01

The present invention is a method and apparatus for using ring resonators to produce narrow linewidth hybrid semiconductor lasers. According to one embodiment of the present invention, the narrow linewidths are produced by combining the semiconductor gain chip with a narrow pass band external feedback element. The semi conductor laser is produced using a ring resonator which, combined with a Bragg grating, acts as the external feedback element. According to another embodiment of the present invention, the proposed integrated optics ring resonator is based on plasma enhanced chemical vapor deposition (PECVD) SiO.sub.2 /SiON/SiO.sub.2 waveguide technology.

Experimental evaluation of two premixing-prevaporizing fuel injection concepts for a gas turbine catalytic combustor

NASA Technical Reports Server (NTRS)

Tacina, R.

1976-01-01

A premixing-prevaporizing fuel system for a gas turbine catalytic combustor has been developed and evaluated. Spatial fuel distribution and degree of vaporization were measured at inlet temperatures up to 800 K and fuel-air ratios of 0.01 and 0.025. The test pressure was 0.5 MPa; velocity was 20 m/sec. Both a multiple-jet cross-stream injector and a splash-groove injector with a 30 deg air swirler exhibited a uniform fuel distribution and a high degree of vaporization with little total pressure drop. Fuel oxidation reactions were observed at the 800 K inlet air temperature, indicating that a different design concept is necessary for application with an automotive gas turbine.

Ocular Biometrics of Myopic Eyes With Narrow Angles.

PubMed

Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

2016-02-01

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

Intramyocardial arterial narrowing in dogs with subaortic stenosis.

PubMed

Falk, T; Jönsson, L; Pedersen, H D

2004-09-01

Earlier studies have described intramyocardial arterial narrowing based on hyperplasia and hypertrophy of the vessel wall in dogs with subaortic stenosis (SAS). In theory, such changes might increase the risk of sudden death, as they seem to do in heart disease in other species. This retrospective pathological study describes and quantifies intramyocardial arterial narrowing in 44 dogs with naturally occurring SAS and in eight control dogs. The majority of the dogs with SAS died suddenly (n=27); nine had died or been euthanased with signs of heart failure and eight were euthanased without clinical signs. Dogs with SAS had significantly narrower intramyocardial arteries (P<0.001) and more myocardial fibrosis (P<0.001) than control dogs. Male dogs and those with more severe hypertrophy had more vessel narrowing (P=0.02 and P=0.02, respectively), whereas dogs with dilated hearts had slightly less pronounced arterial thickening (P=0.01). Arterial narrowing was not related to age, but fibrosis increased with age (P=0.047). Dogs that died suddenly did not have a greater number of arterial changes than other dogs with SAS. This study suggests that most dogs with SAS have intramyocardial arterial narrowing and that the risk of dying suddenly is not significantly related to the overall degree of vessel obliteration.

Line Narrowing Parameter Measurement by Modulation Spectroscopy

NASA Technical Reports Server (NTRS)

Dharamsi, Amin N.

1998-01-01

Accurate Characterization of Oxygen A-Band Line Parameters by Wavelength Modulation Spectroscopy with tunable diode lasers is an ongoing research at Old Dominion University, under sponsorship from NASA Langley research Center. The work proposed here will be undertaken under the guidance of Dr. William Chu and Dr. Lamont Poole of the Aerosol Research Branch at NASA Langley-Research Center in Hampton, Virginia. The research was started about two years ago and utilizes wavelength modulation absorption spectroscopy with higher harmonic detection, a technique that we developed at Old Dominion University, to obtain the absorption line characteristics of the Oxygen A-band rovibronic lines. Accurate characterization of this absorption band is needed for processing of data that will be obtained in experiments such as the NASA Stratospheric Aerosol and Gas Experiment III (SAGE III) as part of the US Mission to Planet Earth. The research work for Summer Fellowship undertook a measurement of the Dicke line-narrowing parameters of the Oxygen A-Band lines by using wavelength modulation spectroscopy. Our previous theoretical results had indicated that such a measurement could be done sensitively and in a convenient fashion by using this type of spectroscopy. In particular, theoretical results had indicated that the signal magnitude would depend on pressure in a manner that was very sensitive to the narrowing parameter. One of the major tasks undertaken during the summer of 1998 was to establish experimentally that these theoretical predictions were correct. This was done successfully and the results of the work are being prepared for publication. Experimental Results were obtained in which the magnitude of the signal was measured as a function of pressure, for various harmonic detection orders (N = 1, 2, 3, 4, 5). A comparison with theoretical results was made, and it was shown that the agreement between theory and experiment was very good. More importantly, however, it was shown

Self-aliquoting micro-grooves in combination with laser ablation-ICP-mass spectrometry for the analysis of challenging liquids: quantification of lead in whole blood.

PubMed

Nischkauer, Winfried; Vanhaecke, Frank; Limbeck, Andreas

2016-08-01

We present a technique for the fast screening of the lead concentration in whole blood samples using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The whole blood sample is deposited on a polymeric surface and wiped across a set of micro-grooves previously engraved into the surface. The engraving of the micro-grooves was accomplished with the same laser system used for LA-ICP-MS analysis. In each groove, a part of the liquid blood is trapped, and thus, the sample is divided into sub-aliquots. These aliquots dry quasi instantly and are then investigated by means of LA-ICP-MS. For quantification, external calibration against aqueous standard solutions was relied on, with iron as an internal standard to account for varying volumes of the sample aliquots. The (208)Pb/(57)Fe nuclide ratio used for quantification was obtained via a data treatment protocol so far only used in the context of isotope ratio determination involving transient signals. The method presented here was shown to provide reliable results for Recipe ClinChek® Whole Blood Control levels I-III (nos. 8840-8842), with a repeatability of typically 3 % relative standard deviation (n = 6, for Pb at 442 μg L(-1)). Spiked and non-spiked real whole blood was analysed as well, and the results were compared with those obtained via dilution and sectorfield ICP-MS. A good agreement between both methods was observed. The detection limit (3 s) for lead in whole blood was established to be 10 μg L(-1) for the laser ablation method presented here. Graphical Abstract Micro-grooves are filled with whole blood, dried, and analyzed by laser ablation ICP-mass spectrometry. Notice that the laser moves in perpendicular direction with regard to the micro-grooves.

Magnetic roller gas gate employing transonic sweep gas flow to isolate regions of differing gaseous composition or pressure

DOEpatents

Doehler, Joachim

1994-12-20

Disclosed herein is an improved gas gate for interconnecting regions of differing gaseous composition and/or pressure. The gas gate includes a narrow, elongated passageway through which substrate material is adapted to move between said regions and inlet means for introducing a flow of non-contaminating sweep gas into a central portion of said passageway. The gas gate is characterized in that the height of the passageway and the flow rate of the sweep gas therethrough provides for transonic flow of the sweep gas between the inlet means and at least one of the two interconnected regions, thereby effectively isolating one region, characterized by one composition and pressure, from another region, having a differing composition and/or pressure, by decreasing the mean-free-path length between collisions of diffusing species within the transonic flow region. The gas gate preferably includes a manifold at the juncture point where the gas inlet means and the passageway interconnect.

From old alkylating agents to new minor groove binders.

PubMed

Puyo, Stéphane; Montaudon, Danièle; Pourquier, Philippe

2014-01-01

Alkylating agents represent the oldest class of anticancer agents with the approval of mechloretamine by the FDA in 1949. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in the treatment of specific malignancies, sometimes representing the unique option for the treatment of refractory tumors. Here, we are reviewing the major classes of alkylating agents, with a particular focus on the latest generations of compounds that specifically target the minor groove of the DNA. These naturally occurring derivatives have a unique mechanism of action that explains the recent regain of interest in developing new classes of alkylating agents that could be used in combination with other anticancer drugs to enhance tumor response in the clinic. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Gas vesicles.

PubMed Central

Walsby, A E

1994-01-01

The gas vesicle is a hollow structure made of protein. It usually has the form of a cylindrical tube closed by conical end caps. Gas vesicles occur in five phyla of the Bacteria and two groups of the Archaea, but they are mostly restricted to planktonic microorganisms, in which they provide buoyancy. By regulating their relative gas vesicle content aquatic microbes are able to perform vertical migrations. In slowly growing organisms such movements are made more efficiently than by swimming with flagella. The gas vesicle is impermeable to liquid water, but it is highly permeable to gases and is normally filled with air. It is a rigid structure of low compressibility, but it collapses flat under a certain critical pressure and buoyancy is then lost. Gas vesicles in different organisms vary in width, from 45 to > 200 nm; in accordance with engineering principles the narrower ones are stronger (have higher critical pressures) than wide ones, but they contain less gas space per wall volume and are therefore less efficient at providing buoyancy. A survey of gas-vacuolate cyanobacteria reveals that there has been natural selection for gas vesicles of the maximum width permitted by the pressure encountered in the natural environment, which is mainly determined by cell turgor pressure and water depth. Gas vesicle width is genetically determined, perhaps through the amino acid sequence of one of the constituent proteins. Up to 14 genes have been implicated in gas vesicle production, but so far the products of only two have been shown to be present in the gas vesicle: GvpA makes the ribs that form the structure, and GvpC binds to the outside of the ribs and stiffens the structure against collapse. The evolution of the gas vesicle is discussed in relation to the homologies of these proteins. Images PMID:8177173

High-resolution spectroscopy of the extended narrow-line region of IC 5063 and NGC 7212

NASA Astrophysics Data System (ADS)

Congiu, E.; Contini, M.; Ciroi, S.; Cracco, V.; Berton, M.; Di Mille, F.; Frezzato, M.; La Mura, G.; Rafanelli, P.

2017-10-01

We studied the properties of the gas of the extended narrow-line region (ENLR) of two Seyfert 2 galaxies: IC 5063 and NGC 7212. We analysed high-resolution spectra to investigate how the main properties of this region depend on the gas velocity. We divided the emission lines in velocity bins and we calculated several line ratios. Diagnostic diagrams and suma composite models (photoionization + shocks) show that in both galaxies there might be evidence of shocks significantly contributing in the gas ionization at high |V|, even though photoionization from the active nucleus remains the main ionization mechanism. In IC 5063, the ionization parameter depends on V and its trend might be explained assuming an hollow bi-conical shape for the ENLR, with one of the edges aligned with the galaxy disc. On the other hand, NGC 7212 does not show any kind of dependence. The models show that solar O/H relative abundances reproduce the observed spectra in all the analysed regions. They also revealed an high fragmentation of the gas clouds, suggesting that the complex kinematics observed in these two objects might be caused by interaction between the interstellar medium and high-velocity components, such as jets.

Extreme Gaseous Outflows in Radio-Loud Narrow-Line Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Komossa, S.; Xu, D. W.; Wagner, A. Y.

2018-04-01

We present four radio-loud NLS1 galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km/s, above the escape velocity of the host galaxies. The forbidden lines show strong broadening, up to 2270 km/s. An ionization stratification (higher line shift at higher ionization potential) implies that we see a large-scale outflow rather than single, localized jet-cloud interactions. Similarly, the paucity of zero-velocity [OIII]λ5007 emitting gas implies the absence of a second narrow-line region (NLR) component at rest, and therefore a large part of the high-ionization NLR is affected by the outflow. Given the radio loudness of these NLS1 galaxies, the observations are consistent with a pole on view onto their central engines, so that the effects of polar outflows are maximized. In addition, a very efficient driving mechanism is required, to reach the high observed velocities. We explore implications from recent hydrodynamic simulations of the interaction between fast winds or jets with the large-scale NLR. Overall, the best agreement with observations (and especially the high outflow speeds of the [NeV] emitting gas) can be reached if the NLS1 galaxies are relatively young sources with lifetimes not much exceeding 1 Myr. These systems represent sites of strong feedback at NLR scales at work, well below redshift one.

Solar-pumped gas laser development

NASA Technical Reports Server (NTRS)

Wilson, J. W.

1980-01-01

A survey of gas properties through detailed kinetic models led to the identification of critical gas parameters for use in choosing appropriate gas combinations for solar pumped lasers. Broadband photoabsorption in the visible or near UV range is required to excite large volumes of gas and to insure good solar absorption efficiency. The photoexcitation density is independent of the absorption bandwidth. The state excited must be a metastable state which is not quenched by the parent gas. The emission bandwidth must be less than 10 A to insure lasing threshold over reasonable gain lengths. The system should show a high degree of chemical reversibility and an insensitivity to increasing temperature. Other properties such as good quantum efficiency and kinetic efficiency are also implied. Although photoexcitation of electronic vibrational transitions is considered as a possible system if the emission bands sufficiently narrow, it appears that photodissociation into atomic metastables is more likely to result in a successful solar pumped laser system.

Superdiffusive gas recovery from nanopores

NASA Astrophysics Data System (ADS)

Wu, Haiyi; He, Yadong; Qiao, Rui

2016-11-01

Understanding the recovery of gas from reservoirs featuring pervasive nanopores is essential for effective shale gas extraction. Classical theories cannot accurately predict such gas recovery and many experimental observations are not well understood. Here we report molecular simulations of the recovery of gas from single nanopores, explicitly taking into account molecular gas-wall interactions. We show that, in very narrow pores, the strong gas-wall interactions are essential in determining the gas recovery behavior both quantitatively and qualitatively. These interactions cause the total diffusion coefficients of the gas molecules in nanopores to be smaller than those predicted by kinetic theories, hence slowing down the rate of gas recovery. These interactions also lead to significant adsorption of gas molecules on the pore walls. Because of the desorption of these gas molecules during gas recovery, the gas recovery from the nanopore does not exhibit the usual diffusive scaling law (i.e., the accumulative recovery scales as R ˜t1 /2 ) but follows a superdiffusive scaling law R ˜tn (n >0.5 ), which is similar to that observed in some field experiments. For the system studied here, the superdiffusive gas recovery scaling law can be captured well by continuum models in which the gas adsorption and desorption from pore walls are taken into account using the Langmuir model.

The fundamental ribosomal RNA transcription initiation factor-IB (TIF-IB, SL1, factor D) binds to the rRNA core promoter primarily by minor groove contacts.

PubMed

Geiss, G K; Radebaugh, C A; Paule, M R

1997-11-14

Acanthamoeba castellanii transcription initiation factor-IB (TIF-IB) is the TATA-binding protein-containing transcription factor that binds the rRNA promoter to form the committed complex. Minor groove-specific drugs inhibit TIF-IB binding, with higher concentrations needed to disrupt preformed complexes because of drug exclusion by bound TIF-IB. TIF-IB/DNA interactions were mapped by hydroxyl radical and uranyl nitrate footprinting. TIF-IB contacts four minor grooves in its binding site. TIF-IB and DNA wrap around each other in a right-handed superhelix of high pitch, so the upstream and downstream contacts are on opposite faces of the helix. Dimethyl sulfate protection assays revealed limited contact with a few guanines in the major groove. This detailed analysis suggests significant DNA conformation dependence of the interaction.

Gas arc constriction for plasma arc welding

NASA Technical Reports Server (NTRS)

McGee, William F. (Inventor); Rybicki, Daniel J. (Inventor)

1994-01-01

A welding torch for plasma arc welding apparatus has an inert gas applied circumferentially about the arc column externally of the constricting nozzle so as to apply a constricting force on the arc after it has exited the nozzle orifice and downstream of the auxiliary shielding gas. The constricting inert gas is supplied to a plenum chamber about the body of the torch and exits through a series of circumferentially disposed orifices in an annular wall forming a closure at the forward end of the constricting gas plenum chamber. The constricting force of the circumferential gas flow about the arc concentrates and focuses the arc column into a more narrow and dense column of energy after exiting the nozzle orifice so that the arc better retains its energy density prior to contacting the workpiece.

Flow Regime Transition in Inner Grooved Minichannel Cold Plates for Cooling Hybrid Electric Power Electronics

DTIC Science & Technology

2013-01-01

reentrant cavities) Corrugated or fluted tubes Screens Inner grooved tubes ( microfin tubes ) Fins Electrohydrodynamic field effect 3.1 Convective... microfin geometries, including 3-D geometries, but most commercial vendors continue to manufacture seamless tubes (46). Figure 6a shows the...enhancement technologies are compiled in table 4. Table 4. Comparison of leading refrigeration tube performance (42). Metric Microfin Tube Twisted

Narrow-linewidth Q-switched random distributed feedback fiber laser.

PubMed

Xu, Jiangming; Ye, Jun; Xiao, Hu; Leng, Jinyong; Wu, Jian; Zhang, Hanwei; Zhou, Pu

2016-08-22

A narrow-linewidth Q-switched random fiber laser (RFL) based on a half-opened cavity, which is realized by narrow-linewidth fiber Bragg grating (FBG) and a section of 3 km passive fiber, has been proposed and experimentally investigated. The narrow-linewidth lasing is generated by the spectral filtering of three FBGs with linewidth of 1.21 nm, 0.56 nm, and 0.12 nm, respectively. The Q switching of the distributed cavity is achieved by placing an acousto-optical modulator (AOM) between the FBG and the passive fiber. The maximal output powers of the narrow-linewidth RFLs with the three different FBGs are 0.54 W, 0.27 W, and 0.08 W, respectively. Furthermore, the repetition rates of the output pulses are 500 kHz, and the pulse durations are about 500 ns. The corresponding pulse energies are about 1.08 μJ, 0.54 μJ, and 0.16 μJ, accordingly. The linewidth of FBG can influence the output characteristics in full scale. The narrower the FBG, the higher the pump threshold; the lower the output power at the same pump level, the more serious the linewidth broadening; and thus the higher the proportion of the CW-ground exists in the output pulse trains. Thanks to the assistance of the band-pass filter (BPF), the proportion of the CW-ground of narrow-linewidth Q-switched RFL under the relative high-pump-low-output condition can be reduced effectively. The experimental results indicate that it is challenging to demonstrate a narrow-linewidth Q-switched RFL with high quality output. But further power scaling and linewidth narrowing is possible in the case of operating parameters, optimization efforts, and a more powerful pump source. To the best of our knowledge, this is the first demonstration of narrow-linewidth generation in a Q-switched RFL.

Turbomachinery Laboratory Texas A and M University research progress on annular gas seals

NASA Technical Reports Server (NTRS)

Childs, Dara W.

1994-01-01

Three helically-grooved seals were tested and the results were compared to the MTI code SPIRALG. A smooth annular seal was tested at six eccentricity ratios from 0 to 0.5. The following are concluded in this viewgraph presentation: (1) Helical-grooved seals provide a substantial reduction in cross-coupled stiffness coefficients. Negative k(sub xy) values are obtained for no-swirl or low-swirl cases. (2) SPIRALG is completely unsuitable for the type of seal tested, namely, turbulent flow, wide grooves and lands, etc. (3) A good analysis code is needed to guide the design of helically-grooved annular seals including groove and smooth sections.

Discovery of a narrow line quasar

NASA Technical Reports Server (NTRS)

Stocke, J.; Liebert, J.; Maccacaro, T.; Griffiths, R. E.; Steiner, J. E.

1982-01-01

A stellar object is reported which, while having X-ray and optical luminosities typical of quasars, has narrow permitted and forbidden emission lines over the observed spectral range. The narrow-line spectrum is high-excitation, the Balmer lines seem to be recombinational, and a redder optical spectrum than that of most quasars is exhibited, despite detection as a weak radio source. The object does not conform to the relationships between H-beta parameters and X-ray flux previously claimed for a large sample of the active galactic nuclei. Because reddish quasars with narrow lines, such as the object identified, may not be found by the standard techniques for the discovery of quasars, the object may be a prototype of a new class of quasars analogous to high-luminosity Seyfert type 2 galaxies. It is suggested that these objects cannot comprise more than 10% of all quasars.

Mechanistic aspects of thioflavin-T self-aggregation and DNA binding: evidence for dimer attack on DNA grooves.

PubMed

Biancardi, A; Biver, T; Burgalassi, A; Mattonai, M; Secco, F; Venturini, M

2014-10-07

Thioflavin-T (TFT) is a fluorescent marker widely employed in biomedical research but the mechanism of its binding to polynucleotides has been poorly understood. This paper presents a study of the mechanisms of TFT self-aggregation and binding to DNA. Relaxation kinetics of TFT solutions show that the cyanine undergoes dimerization followed by dimer isomerisation. The interaction of TFT with DNA has been investigated using static methods, such as spectrophotometric and spectrofluorometric titrations under different conditions (salt content, temperature), fluorescence quenching, viscometric experiments and the T-jump relaxation method. The combined use of these techniques enabled us to show that the TFT monomer undergoes intercalation between the DNA base pairs and external binding according to a branched mechanism. Moreover, it has also been observed that, under dye excess conditions, the TFT dimer binds to the DNA grooves. The molecular structures of intercalated TFT and the groove-bound TFT dimer are obtained by performing QM/MM MD simulations.

Gas Debris Disks: A New Way to Produce Dust Patterns

NASA Technical Reports Server (NTRS)

Kuchner, Marc J.

2012-01-01

Debris disks like those around Fomalhaut and Beta Pictoris show striking dust patterns often attributed to planets. But adding a bit of gas to our models of these disks--too little to detect-could alter this interpretation. Small amounts of gas lead to new dynamical instabilities that may mimic the narrow eccentric rings and other structures planets would create in a gas-free disk. rll discuss these phenomena and whether or not we can still use dust patterns as indicators of hidden exoplanets.

Infants Experience Perceptual Narrowing for Nonprimate Faces

ERIC Educational Resources Information Center

Simpson, Elizabeth A.; Varga, Krisztina; Frick, Janet E.; Fragaszy, Dorothy

2011-01-01

Perceptual narrowing--a phenomenon in which perception is broad from birth, but narrows as a function of experience--has previously been tested with primate faces. In the first 6 months of life, infants can discriminate among individual human and monkey faces. Though the ability to discriminate monkey faces is lost after about 9 months, infants…

Olfactory groove meningioma: discussion of clinical presentation and surgical outcomes following excision via the subcranial approach.

PubMed

Pepper, Jon-Paul; Hecht, Sarah L; Gebarski, Stephen S; Lin, Erin M; Sullivan, Stephen E; Marentette, Lawrence J

2011-11-01

To describe surgical outcomes and radiographic features of olfactory groove meningiomas treated by excision through the subcranial approach. Special emphasis is placed on paranasal sinus and orbit involvement. Retrospective review of a series of patients. Nineteen patients underwent excision of olfactory groove meningioma (OGM) via the transglabellar/subcranial approach between December 1995 and November 2009. Nine patients had previously undergone prior resection at outside institutions, and four had prior radiotherapy in addition to a prior excision. Transglabellar/subcranial surgical approach to the anterior skull base was performed. Tumor histology included three World Health Organization (WHO) grade III lesions, one WHO grade II lesion, and 15 WHO grade I lesions. Fourteen patients had evidence of extension into the paranasal sinuses, with the ethmoid sinus being most commonly involved. Kaplan-Meier estimates of mean overall and disease-free survival were 121.45 months and 93.03 months, respectively. The mean follow-up interval was 41.0 months, and at the time of data analysis three patients had recurrent tumors. Seven (36.8%) patients experienced a major complication in the perioperative period; there were no perioperative mortalities. Orbit invasion was observed in four patients, with optic nerve impingement in 11 patients. Of these, three patients had long-term diplopia. No patients experienced worsening of preoperative visual acuity. Olfactory groove meningiomas demonstrate a propensity to spread into the paranasal sinuses, particularly in recurrent cases. Given a tendency for infiltrative recurrence along the skull base, this disease represents an important area of collaboration between neurosurgery and otolaryngology. The subcranial approach offers excellent surgical access for excision, particularly for recurrences that involve the paranasal sinuses and optic apparatus. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society

The size-luminosity relationship of quasar narrow-line regions

NASA Astrophysics Data System (ADS)

Dempsey, Ross; Zakamska, Nadia L.

2018-07-01

The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105-107 M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g. star formation). We find that the observed saturation of sizes at ˜10 kpc which is observed at high AGN luminosities (Lion ≃ 1046 erg s-1) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size-IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.

The Size-Luminosity Relationship of Quasar Narrow-Line Regions

NASA Astrophysics Data System (ADS)

Dempsey, Ross; Zakamska, Nadia L.

2018-04-01

The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105M⊙ to 107M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g., star formation). We find that the observed saturation of sizes at ˜10kpc which is observed at high AGN luminosities (Lion ≃ 1046erg/s) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size - IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.

Gas Forming a V-Shape Aluminum Sheet into a Trough of Saddle-Contour

NASA Astrophysics Data System (ADS)

Lee, Shyong; Lan, Hsien-Chin; Lee, Jye; Wang, Jian-Yih; Huang, J. C.; Chu, Chun Lin

2012-11-01

A sheet metal trough of aluminum alloys is manufactured by gas-forming process at 500 °C. The product with slope walls is of ~1.2 m long and ~260 mm opening width, comprising two conical sinks at two ends. The depth of one sink apex is ~350 mm, which results in the depth/width ratio reaching 1.4. To form such a complex shape with high aspect ratio, a pre-form of V-shape groove is prepared prior to the gas-forming work. When this double concave trough is turned upside down, the convex contour resembles the back of a twin hump camel. The formability of this configuration depends on the gas pressurization rate profile, the working temperature, material's micro-structure, as well as pre-form design. The latter point is demonstrated by comparing two aluminum alloys, AA5182 and SP5083, with nearly same compositions but very different grain sizes.

Theory of g-factor enhancement in narrow-gap quantum well heterostructures.

PubMed

Krishtopenko, S S; Gavrilenko, V I; Goiran, M

2011-09-28

We report on the study of the exchange enhancement of the g-factor in the two-dimensional (2D) electron gas in n-type narrow-gap semiconductor heterostructures. Our approach is based on the eight-band k⋅p Hamiltonian and takes into account the band nonparabolicity, the lattice deformation, the spin-orbit coupling and the Landau level broadening in the δ-correlated random potential model. Using the 'screened' Hartree-Fock approximation we demonstrate that the exchange g-factor enhancement not only shows maxima at odd values of Landau level filling factors but, due to the conduction band nonparabolicity, persists at even filling factor values as well. The magnitude of the exchange enhancement, the amplitude and the shape of the g-factor oscillations are determined by both the screening of the electron-electron interaction and the Landau level width. The 'enhanced' g-factor values calculated for the 2D electron gas in InAs/AlSb quantum well heterostructures are compared with our earlier experimental data and with those obtained by Mendez et al (1993 Phys. Rev. B 47 13937) in magnetic fields up to 30 T.

Narrow-Line Seyfert 1 Galaxies

NASA Technical Reports Server (NTRS)

Leighly, Karen M.

2000-01-01

The primary work during this year has been the analysis and interpretation of our HST spectra from two extreme Narrow-line Seyfert 1 galaxies (NLS1s) Infrared Astronomy Satellite (IRAS) 13224-3809 and 1H 0707-495. This work has been presented as an invited talk at the workshop entitled "Observational and theoretical progress in the Study of Narrow-line Seyfert 1 Galaxies" held in Bad Honnef, Germany December 8-11, as a contributed talk at the January 2000 AAS meeting in Atlanta, Georgia, and as a contributed talk at the workshop "Probing the Physics of Active Galactic Nuclei by Multiwavelength Monitoring" held at Goddard Space Flight Center June 20-22, 2000.

A blue optical filter for narrow-band imaging in endoscopic capsules

NASA Astrophysics Data System (ADS)

Silva, M. F.; Ghaderi, M.; Goncalves, L. M.; de Graaf, G.; Wolffenbuttel, R. F.; Correia, J. H.

2014-05-01

This paper presents the design, simulation, fabrication, and characterization of a thin-film Fabry-Perot resonator composed of titanium dioxide (TiO2) and silicon dioxide (SiO2) thin-films. The optical filter is developed to be integrated with a light emitting diode (LED) for enabling narrow-band imaging (NBI) in endoscopy. The NBI is a high resolution imaging technique that uses spectrally centered blue light (415 nm) and green light (540 nm) to illuminate the target tissue. The light at 415 nm enhances the imaging of superficial veins due to their hemoglobin absorption, while the light at 540 nm penetrates deeper into the mucosa, thus enhances the sub-epithelial vessels imaging. Typically the endoscopes and endoscopic capsules use white light for acquiring images of the gastrointestinal (GI) tract. However, implementing the NBI technique in endoscopic capsules enhances their capabilities for the clinical applications. A commercially available blue LED with a maximum peak intensity at 404 nm and Full Width Half Maximum (FWHM) of 20 nm is integrated with a narrow band blue filter as the NBI light source. The thin film simulations show a maximum spectral transmittance of 36 %, that is centered at 415 nm with FWHM of 13 nm for combined the blue LED and a Fabry Perot resonator system. A custom made deposition scheme was developed for the fabrication of the blue optical filter by RF sputtering. RF powered reactive sputtering at 200 W with the gas flows of argon and oxygen that are controlled for a 5:1 ratio gives the optimum optical conditions for TiO2 thin films. For SiO2 thin films, a non-reactive RF sputtering at 150 W with argon gas flow at 15 sccm results in the best optical performance. The TiO2 and SiO2 thin films were fully characterized by an ellipsometer in the wavelength range between 250 nm to 1600 nm. Finally, the optical performance of the blue optical filter is measured and presented.

Efficient unidirectional launching of surface plasmons by a cascade asymmetric-groove structure.

PubMed

Song, Xue-Yang; Zhang, Zhengxing; Liao, Huimin; Li, Zhi; Sun, Chengwei; Chen, Jianjun; Gong, Qihuang

2016-03-28

Increasing the unidirectional launching efficiency of surface plasmon polaritons (SPPs) is crucial in plasmonics. Here, we demonstrate that this efficiency may be improved by cascading subwavelength unidirectional SPP launching units. A unidirectional SPP launching efficiency of at least 46% and an extinction ratio of 40 are experimentally demonstrated using a cascade asymmetric-groove structure. Meanwhile, the device is ultracompact, and has a lateral dimension of only 1.1 μm. The proposed structure also presents a broadband response and is easy to fabricate. This high-performance wavelength-scale unidirectional SPP launcher represents an important development in practical SPP sources.

2. Photocopied July 1971 from photostat Jordan Narrows Folder #1, ...

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

2. Photocopied July 1971 from photostat Jordan Narrows Folder #1, Engineering Department, Utah Power and Light Co., Salt Lake City, Utah. JORDAN NARROWS STATION. PLAN AND SECTION. - Salt Lake City Water & Electrical Power Company, Jordan Narrows Hydroelectric Plant, Jordan River, Riverton, Salt Lake County, UT

Friction Anisotropy with Respect to Topographic Orientation

PubMed Central

Yu, Chengjiao; Wang, Q. Jane

2012-01-01

Friction characteristics with respect to surface topographic orientation were investigated using surfaces of different materials and fabricated with grooves of different scales. Scratching friction tests were conducted using a nano-indentation-scratching system with the tip motion parallel or perpendicular to the groove orientation. Similar friction anisotropy trends were observed for all the surfaces studied, which are (1) under a light load and for surfaces with narrow grooves, the tip motion parallel to the grooves offers higher friction coefficients than does that perpendicular to them, (2) otherwise, equal or lower friction coefficients are found under this motion. The influences of groove size relative to the diameter of the mating tip (as a representative asperity), surface contact stiffness, contact area, and the characteristic stiction length are discussed. The appearance of this friction anisotropy is independent of material; however, the boundary and the point of trend transition depend on material properties. PMID:23248751

Nanopatterning as a Probe of Unstable Growth on GaAs(001)

NASA Astrophysics Data System (ADS)

Cosert, Krista; Lin, Chuan-Fu; Hammouda, Ajmi; Kan, Hung-Chih; Subrumaniam, Kanakaraju; Richardson, Chris; Phaneuf, Ray

2009-03-01

We report on observations of unstable growth on nanopatterned GaAs(001) surfaces. For growth at 500^oC, 1 ML/sec and an As2/Ga beam equivalent pressure ratio of 10:1, we find that grooves oriented at right angles to [110] produce a build up of ridges of GaAs at the upper edges, while for grooves oriented at right angles to [110] no ridges form; instead cusps evolve at the bottoms of such grooves [1]. The cusp-forming grooves show a pronounced initial amplification of depth during growth which changes with length/width ratio, and become more narrow. The ridge-forming grooves instead broaden during growth. We compare these experimental observations with kinetic Monte Carlo simulations in which a small anisotropic Ehrlich-Schwoebel barrier is included. [1] T. Tadayyon-Eslami, H.-C. Kan, L. C. Calhoun and R. J. Phaneuf, Phys. Rev. Lett. 97, 126101 (2006)

A molecular gas-rich GRB host galaxy at the peak of cosmic star formation

NASA Astrophysics Data System (ADS)

Arabsalmani, M.; Le Floc'h, E.; Dannerbauer, H.; Feruglio, C.; Daddi, E.; Ciesla, L.; Charmandaris, V.; Japelj, J.; Vergani, S. D.; Duc, P.-A.; Basa, S.; Bournaud, F.; Elbaz, D.

2018-05-01

We report the detection of the CO(3-2) emission line from the host galaxy of gamma-ray burst (GRB) 080207 at z = 2.086. This is the first detection of molecular gas in emission from a GRB host galaxy beyond redshift 1. We find this galaxy to be rich in molecular gas with a mass of 1.1 × 10^{11} M_{{\\odot }} assuming αCO = 4.36 M_{{\\odot }} (K km s^{-1} pc^2)^{-1}. The molecular gas mass fraction of the galaxy is ˜0.5, typical of star-forming galaxies (SFGs) with similar stellar masses and redshifts. With an SFR_{FIR} of 260 M_{{\\odot }} yr^{-1}, we measure a molecular gas depletion time-scale of 0.43 Gyr, near the peak of the depletion time-scale distribution of SFGs at similar redshifts. Our findings are therefore in contradiction with the proposed molecular gas deficiency in GRB host galaxies. We argue that the reported molecular gas deficiency for GRB hosts could be the artefact of improper comparisons or neglecting the effect of the typical low metallicities of GRB hosts on the CO-to-molecular-gas conversion factor. We also compare the kinematics of the CO(3-2) emission line to that of the H α emission line from the host galaxy. We find the H α emission to have contributions from two separate components, a narrow and a broad one. The narrow component matches the CO emission well in velocity space. The broad component, with a full width at half-maximum of ˜1100 km s^{-1}, is separated by +390 km s^{-1} in velocity space from the narrow component. We speculate this broad component to be associated with a powerful outflow in the host galaxy or in an interacting system.

Outcomes After Conservative, Endoscopic, and Surgical Treatment of Groove Pancreatitis: A Systematic Review.

PubMed

Kager, Liesbeth M; Lekkerkerker, Selma J; Arvanitakis, Marianna; Delhaye, Myriam; Fockens, Paul; Boermeester, Marja A; van Hooft, Jeanin E; Besselink, Marc G

2017-09-01

Groove pancreatitis (GP) is a focal form of chronic pancreatitis affecting the paraduodenal groove area, for which consensus on diagnosis and management is lacking. We performed a systematic review of the literature to determine patient characteristics and imaging features of GP and to evaluate clinical outcomes after treatment. Eight studies were included reporting on 335 GP patients with a median age of 47 years (range, 34 to 64 y), with 90% male, 87% smokers, and 87% alcohol consumption, and 47 months (range, 15 to 122 mo) of follow-up. Most patients presented with abdominal pain (91%) and/or weight loss (78%). Imaging frequently showed cystic lesions (91%) and duodenal stenosis (60%).Final treatment was conservative (eg, pain medication) in 29% of patients. Endoscopic treatment (eg, pseudocyst drainage) was applied in 19% of patients-34% of these patients were subsequently referred for surgery. Overall, 59% of patients were treated surgically (eg, pancreatoduodenectomy). Complete symptom relief was observed in 50% of patients who were treated conservatively, 57% who underwent endoscopic treatment, and 79% who underwent surgery. GP is associated with male gender, smoking, and alcohol consumption. The vast majority of patients presents with abdominal pain and with cystic lesions on imaging. Although surgical treatment seems to be the most effective, both conservative and endoscopic treatment are successful in about half of patients. A stepwise treatment algorithm starting with the least invasive treatment options seems advisable.

An enhanced narrow-band imaging method for the microvessel detection

NASA Astrophysics Data System (ADS)

Yu, Feng; Song, Enmin; Liu, Hong; Wan, Youming; Zhu, Jun; Hung, Chih-Cheng

2018-02-01

A medical endoscope system combined with the narrow-band imaging (NBI), has been shown to be a superior diagnostic tool for early cancer detection. The NBI can reveal the morphologic changes of microvessels in the superficial cancer. In order to improve the conspicuousness of microvessel texture, we propose an enhanced NBI method to improve the conspicuousness of endoscopic images. To obtain the more conspicuous narrow-band images, we use the edge operator to extract the edge information of the narrow-band blue and green images, and give a weight to the extracted edges. Then, the weighted edges are fused with the narrow-band blue and green images. Finally, the displayed endoscopic images are reconstructed with the enhanced narrow-band images. In addition, we evaluate the performance of enhanced narrow-band images with different edge operators. Experimental results indicate that the Sobel and Canny operators achieve the best performance of all. Compared with traditional NBI method of Olympus company, our proposed method has more conspicuous texture of microvessel.

Development of gas-to-gas lift pad dynamic seals, volumes 1 and 2

NASA Technical Reports Server (NTRS)

Pope, A. N.; Pugh, D. W.

1987-01-01

Dynamic tests were performed on self acting (hydrodynamic) carbon face rotary shaft seals to assess their potential, relative to presently used labyrinth seals, for improving performance of aircraft gas turbine engines by reducing air leakage flow rate at compressor end seal locations. Three self acting bearing configurations, designed to supply load support at the interface of the stationary carbon seal and rotating seal race, were tested. Two configurations, the shrouded taper and shrouded flat step, were incorporated on the face of the stationary carbon seal element. The third configuration, inward pumping spiral grooves, was incorporated on the hard faced surface of the rotating seal race. Test results demonstrated seal leakage air flow rates from 75 to 95% lower that can be achieved with best state-of-the-art labyrinth designs and led to identification of the need for a more geometrically stable seal design configuration which is presently being manufactured for subsequent test evaluation.

Acquisition and visualization techniques for narrow spectral color imaging.

PubMed

Neumann, László; García, Rafael; Basa, János; Hegedüs, Ramón

2013-06-01

This paper introduces a new approach in narrow-band imaging (NBI). Existing NBI techniques generate images by selecting discrete bands over the full visible spectrum or an even wider spectral range. In contrast, here we perform the sampling with filters covering a tight spectral window. This image acquisition method, named narrow spectral imaging, can be particularly useful when optical information is only available within a narrow spectral window, such as in the case of deep-water transmittance, which constitutes the principal motivation of this work. In this study we demonstrate the potential of the proposed photographic technique on nonunderwater scenes recorded under controlled conditions. To this end three multilayer narrow bandpass filters were employed, which transmit at 440, 456, and 470 nm bluish wavelengths, respectively. Since the differences among the images captured in such a narrow spectral window can be extremely small, both image acquisition and visualization require a novel approach. First, high-bit-depth images were acquired with multilayer narrow-band filters either placed in front of the illumination or mounted on the camera lens. Second, a color-mapping method is proposed, using which the input data can be transformed onto the entire display color gamut with a continuous and perceptually nearly uniform mapping, while ensuring optimally high information content for human perception.

The Role of Radiation Pressure in the Narrow Line Regions of Seyfert Host Galaxies

NASA Astrophysics Data System (ADS)

Davies, Rebecca L.; Dopita, Michael A.; Kewley, Lisa; Groves, Brent; Sutherland, Ralph; Hampton, Elise J.; Shastri, Prajval; Kharb, Preeti; Bhatt, Harish; Scharwächter, Julia; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; James, Bethan; Juneau, Stéphanie; Srivastava, Shweta

2016-06-01

We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ˜ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ˜ 0 to -3.2 ≲ log U ≲ -3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

Adding Some Gas Can Completely Change How an Object in a Liquid-Filled Housing Responds to Vibration

NASA Astrophysics Data System (ADS)

Torczynski, J. R.; O'Hern, T. J.; Clausen, J. R.

2015-11-01

Adding a little gas can completely change the motion of an object in a liquid-filled housing during vibration. A common system exhibiting this behavior is a spring-supported piston in a liquid-filled cylinder, where the gaps between them are narrow and depend on the piston position. When gas is absent, the piston's vibrational response is highly overdamped due to forcing viscous liquid through narrow gaps. When a small amount of gas is added, Bjerknes forces cause some of the gas to migrate below the piston. The resulting two gas regions form a pneumatic spring that enables the liquid to move with the piston, with the result that very little liquid is forced through the narrow gaps. This ``Couette mode'' has low damping and thus has a strong resonance near the frequency given by the pneumatic spring constant and the piston mass. At this frequency, the piston response is large, and the nonlinearity from the gap geometry produces a net force on the piston. This ``rectified'' force can be many times the piston's weight and can cause the piston to compress its supporting spring. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Associations between narrow angle and adult anthropometry: the Liwan Eye Study.

PubMed

Jiang, Yuzhen; He, Mingguang; Friedman, David S; Khawaja, Anthony P; Lee, Pak Sang; Nolan, Winifred P; Yin, Qiuxia; Foster, Paul J

2014-06-01

To assess the associations between narrow angle and adult anthropometry. Chinese adults aged 50 years and older were recruited from a population-based survey in the Liwan District of Guangzhou, China. Narrow angle was defined as the posterior trabecular meshwork not visible under static gonioscopy in at least three quadrants (i.e. a circumference of at least 270°). Logistic regression models were used to examine the associations between narrow angle and anthropomorphic measures (height, weight and body mass index, BMI). Among the 912 participants, lower weight, shorter height, and lower BMI were significantly associated with narrower angle width (tests for trend: mean angle width in degrees vs weight p < 0.001; vs height p < 0.001; vs BMI p = 0.012). In univariate analyses, shorter height, lower weight and lower BMI were all significantly associated with greater odds of narrow angle. The crude association between height and narrow angle was largely attributable to a stronger association with age and sex. Lower BMI and weight remained significantly associated with narrow angle after adjustment for height, age, sex, axial ocular biometric measures and education. In analyses stratified by sex, the association between BMI and narrow angle was only observed in women. Lower BMI and weight were associated with significantly greater odds of narrow angle after adjusting for age, education, axial ocular biometric measures and height. The odds of narrow angle increased 7% per 1 unit decrease in BMI. This association was most evident in women.

Duplex and triplex formation of mixed pyrimidine oligonucleotides with stacking of phenyl-triazole moieties in the major groove.

PubMed

Andersen, Nicolai Krog; Døssing, Holger; Jensen, Frank; Vester, Birte; Nielsen, Poul

2011-08-05

5-(1-Phenyl-1,2,3-triazol-4-yl)-2'-deoxycytidine was synthesized from a modified CuAAC protocol and incorporated into mixed pyrimidine oligonucleotide sequences together with the corresponding 5-(1-phenyl-1,2,3-triazol-4-yl)-2'-deoxyuridine. With consecutive incorporations of the two modified nucleosides, improved duplex formation with a complementary RNA and improved triplex formation with a complementary DNA duplex were observed. The improvement is due to π-π stacking of the phenyl-triazole moieties in the major groove. The strongest stacking and most pronounced positive influence on thermal stability was found in between the uridine analogues or with the cytidine analogue placed in the 3' direction to the uridine analogue. Modeling indicated a different orientation of the phenyl-triazole moieties in the major groove to account for the difference between the two nucleotides. The modified oligonucleotides were all found to be significantly stabilized toward nucleolytic degration.

Gas transfer in a bubbly wake flow

NASA Astrophysics Data System (ADS)

Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.

2016-05-01

The present work reports simultaneous bubble size and gas transfer measurements in a bubbly wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. Bubble size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size bubbles and a reduced weighted mean bubble size. Bubble-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that characteristic turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.

Hot Wax Sweeps Debris From Narrow Passages

NASA Technical Reports Server (NTRS)

Ricklefs, Steven K.

1990-01-01

Safe and effective technique for removal of debris and contaminants from narrow passages involves entrainment of undesired material in thermoplastic casting material. Semisolid wax slightly below melting temperature pushed along passage by pressurized nitrogen to remove debris. Devised to clean out fuel passages in main combustion chamber of Space Shuttle main engine. Also applied to narrow, intricate passages in internal-combustion-engine blocks, carburetors, injection molds, and other complicated parts.

Fracture strength and probability of survival of narrow and extra-narrow dental implants after fatigue testing: In vitro and in silico analysis.

PubMed

Bordin, Dimorvan; Bergamo, Edmara T P; Fardin, Vinicius P; Coelho, Paulo G; Bonfante, Estevam A

2017-07-01

To assess the probability of survival (reliability) and failure modes of narrow implants with different diameters. For fatigue testing, 42 implants with the same macrogeometry and internal conical connection were divided, according to diameter, as follows: narrow (Ø3.3×10mm) and extra-narrow (Ø2.9×10mm) (21 per group). Identical abutments were torqued to the implants and standardized maxillary incisor crowns were cemented and subjected to step-stress accelerated life testing (SSALT) in water. The use-level probability Weibull curves, and reliability for a mission of 50,000 and 100,000 cycles at 50N, 100, 150 and 180N were calculated. For the finite element analysis (FEA), two virtual models, simulating the samples tested in fatigue, were constructed. Loading at 50N and 100N were applied 30° off-axis at the crown. The von-Mises stress was calculated for implant and abutment. The beta (β) values were: 0.67 for narrow and 1.32 for extra-narrow implants, indicating that failure rates did not increase with fatigue in the former, but more likely were associated with damage accumulation and wear-out failures in the latter. Both groups showed high reliability (up to 97.5%) at 50 and 100N. A decreased reliability was observed for both groups at 150 and 180N (ranging from 0 to 82.3%), but no significant difference was observed between groups. Failure predominantly involved abutment fracture for both groups. FEA at 50N-load, Ø3.3mm showed higher von-Mises stress for abutment (7.75%) and implant (2%) when compared to the Ø2.9mm. There was no significant difference between narrow and extra-narrow implants regarding probability of survival. The failure mode was similar for both groups, restricted to abutment fracture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Associations between Narrow Angle and Adult Anthropometry: The Liwan Eye Study

PubMed Central

Jiang, Yuzhen; He, Mingguang; Friedman, David S.; Khawaja, Anthony P.; Lee, Pak Sang; Nolan, Winifred P.; Yin, Qiuxia; Foster, Paul J.

2015-01-01

Purpose To assess the associations between narrow angle and adult anthropometry. Methods Chinese adults aged 50 years and older were recruited from a population-based survey in the Liwan District of Guangzhou, China. Narrow angle was defined as the posterior trabecular meshwork not visible under static gonioscopy in at least three quadrants (i.e. a circumference of at least 270°). Logistic regression models were used to examine the associations between narrow angle and anthropomorphic measures (height, weight and body mass index, BMI). Results Among the 912 participants, lower weight, shorter height, and lower BMI were significantly associated with narrower angle width (tests for trend: mean angle width in degrees vs weight p<0.001; vs height p<0.001; vs BMI p = 0.012). In univariate analyses, shorter height, lower weight and lower BMI were all significantly associated with greater odds of narrow angle. The crude association between height and narrow angle was largely attributable to a stronger association with age and sex. Lower BMI and weight remained significantly associated with narrow angle after adjustment for height, age, sex, axial ocular biometric measures and education. In analyses stratified by sex, the association between BMI and narrow angle was only observed in women. Conclusion Lower BMI and weight were associated with significantly greater odds of narrow angle after adjusting for age, education, axial ocular biometric measures and height. The odds of narrow angle increased 7% per 1 unit decrease in BMI. This association was most evident in women. PMID:24707840

[The supportive outcome of periodontal non-surgical therapy to severe chronic periodontitis accompanied with malformed lingual groove in lateral incisor for 6 years: a case report].

PubMed

Li, Zheng; Kang, Jun

2011-06-01

To track the initiating and developing process of one case diagnosed as chronic periodontitis accompanied with malformed lingual groove in maxillary lateral incisor and report the long-term prognosis to the periodontal conservative and supportive therapy. The patient was diagnosed with mild chronic periodontitis 6 years ago and accepted routine periodontal scaling and root planning (SRP) plus supportive periodontal therapy (SPT) one time. Two years later the periodontal condition deteriorated by deep pockets in molars and severe bone destruction around the maxillary lateral incisor with malformed lingual groove. After SRP in sites which pocket depth more than 4mm plus root canal therapy and lingual groove plasty of maxillary right lateral incisor, the SPT regularly proceeded at 3rd, 6th and 12th month. At present the whole periodontal tissue was healthy, the bone lesion around maxillary lateral incisor recovered well, the tooth had no mobile, the cosmetic effect andtooth function was in good state, and the patient was very satisfied.

Random-hole optical fiber evanescent-wave gas sensing.

PubMed

Pickrell, G; Peng, W; Wang, A

2004-07-01

Research on development of optical gas sensors based on evanescent-wave absorption in random-hole optical fibers is described. A process to produce random-hole optical fibers was recently developed that uses a novel in situ bubble formation technique. Gas molecules that exhibit characteristic vibrational absorption lines in the near-IR region that correspond to the transmission window for silica optical fiber have been detected through the evanescent field of the guided mode in the pore region. The presence of the gas molecules in the holes of the fiber appears as a loss at wavelengths that are characteristic of the particular gas species present in the holes. An experimental setup was constructed with these holey fibers for detection of acetylene gas. The results clearly demonstrate the characteristic absorptions in the optical spectra that correspond to the narrow-line absorptions of the acetylene gas, and this represents what is to our knowledge the first report of random-hole fiber gas sensing in the literature.

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study.

PubMed

Romero-Hermida, M I; Romero-Enrique, J M; Morales-Flórez, V; Esquivias, L

2016-08-21

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N2, CO2, and O2, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO2 concentrations and low temperatures, the CO2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

Ultra-thin narrow-band, complementary narrow-band, and dual-band metamaterial absorbers for applications in the THz regime

NASA Astrophysics Data System (ADS)

Astorino, Maria Denise; Frezza, Fabrizio; Tedeschi, Nicola

2017-02-01

In this paper, ultra-thin narrow-band, complementary narrow-band, and dual-band metamaterial absorbers (MMAs), exploiting the same electric ring resonator configuration, are investigated at normal and oblique incidence for both transverse electric (TE) and transverse magnetic (TM) polarizations, and with different physical properties in the THz regime. In the analysis of the ultra-thin narrow-band MMA, the limit of applicability of the transmission line model has been overcome with the introduction of a capacitance which considers the z component of the electric field. These absorbing structures have shown a wide angular response and a polarization-insensitive behavior due to the introduction of a conducting ground plane and to the four-fold rotational symmetry of the resonant elements around the propagation axis. We have adopted a retrieval procedure to extract the effective electromagnetic parameters of the proposed MMAs and we have compared the simulated and analytical results through the interference theory.

Searching for the influence radius of AGN in nearby narrow emission-line galaxies using the CALIFA survey

NASA Astrophysics Data System (ADS)

Robleto-Orús, A. C.; Torres-Papaqui, J. P.; Coziol, R.; Morales-Vargas, A.; Romero-Cruz, F. J.; Ortega-Minakata, R. A.; Chow-Martinez, M.; Trejo-Alonso, J. J.

2017-07-01

In narrow emission-line galaxies, one important problem consists in discriminating gas ionization due to an AGN and gas ionization due to OB stars in active star-forming regions. This problem becomes more acute in case of AGNs classified as transition-type objects (TO), where star formation is relatively intense, and for LINERs, where the AGN is very weak. Thanks to the integral field spectroscopy, we have a new way to attack this problem. By definition, OB stars ionize a definite portion of space, the Strömgren's sphere, which size depends on the total luminosity of the star, its temperature, and the density of the surrounding gas. Therefore one expects gas ionized by OB stars to cover limited areas in a galaxy. On the other hand, due to the huge amount of ionizing photons emitted by an AGN, its "influence radius" is expected do be much more extended, in the order of kpc. Using a sample of galaxies from included in the CALIFA survey DR3, we will test a new way to measure the characteristic "influence radius" of AGN with different intensities.

Narrow-band generation in random distributed feedback fiber laser.

PubMed

Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V

2013-07-15

Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.

The C-terminal helix of ribosomal P stalk recognizes a hydrophobic groove of elongation factor 2 in a novel fashion.

PubMed

Tanzawa, Takehito; Kato, Koji; Girodat, Dylan; Ose, Toyoyuki; Kumakura, Yuki; Wieden, Hans-Joachim; Uchiumi, Toshio; Tanaka, Isao; Yao, Min

2018-04-06

Archaea and eukaryotes have ribosomal P stalks composed of anchor protein P0 and aP1 homodimers (archaea) or P1•P2 heterodimers (eukaryotes). These P stalks recruit translational GTPases to the GTPase-associated center in ribosomes to provide energy during translation. The C-terminus of the P stalk is known to selectively recognize GTPases. Here we investigated the interaction between the P stalk and elongation factor 2 by determining the structures of Pyrococcus horikoshii EF-2 (PhoEF-2) in the Apo-form, GDP-form, GMPPCP-form (GTP-form), and GMPPCP-form bound with 11 C-terminal residues of P1 (P1C11). Helical structured P1C11 binds to a hydrophobic groove between domain G and subdomain G' of PhoEF-2, where is completely different from that of aEF-1α in terms of both position and sequence, implying that such interaction characteristic may be requested by how GTPases perform their functions on the ribosome. Combining PhoEF-2 P1-binding assays with a structural comparison of current PhoEF-2 structures and molecular dynamics model of a P1C11-bound GDP form, the conformational changes of the P1C11-binding groove in each form suggest that in response to the translation process, the groove has three states: closed, open, and release for recruiting and releasing GTPases.

Consequences of narrow cyclotron emission from Hercules X-1

NASA Technical Reports Server (NTRS)

Weaver, R. P.

1978-01-01

The implications of the recent observations of a narrow cyclotron line in the hard X-ray spectrum of Hercules X-1 are studied. A Monte Carlo code is used to simulate the X-ray transfer of an intrinsically narrow feature at approximately 56 keV through an opaque, cold magnetospheric shell. The results of this study indicate that if a narrow line can be emitted by the source region, then only about 10% of the photons remain in a narrow feature after scattering through the shell. The remaining photons are scattered into a broad feature (FWHM approximately 30 keV) that peaks near 20 keV. Thus, these calculations indicate that the intrinsic source luminosity of the cyclotron line is at least an order of magnitude greater than the observed luminosity.

An Introverted Starburst: Gas and SSC Formation in NGC 5253

NASA Astrophysics Data System (ADS)

Turner, J. L.; Beck, S. C.

2004-06-01

High resolution Brackett line spectroscopy with the Keck Telescope reveals relatively narrow recombination lines toward the embedded young super star cluster nebula in NGC 5253. The gas within this nebula is almost certainly gravitationally bound by the massive and compact young star cluster.

Grooved Glaucoma Drainage Devices That Continuously Deliver Cyclosporine A Decrease Postsurgical Scar Formation in Rabbit Eyes.

PubMed

Dai, Zhaoxing; Yu, Xiaobo; Sun, Jianguo; Sun, Xinghuai

2017-03-01

To study the functional outcomes of filtration surgery by implanting improved glaucoma drainage devices (GDDs) comprising surface grooves and a composite coating of cyclosporine A (CsA) and PLGA in experimental rabbit eyes. Improved GDDs were designed and prepared by modifying normal GDD with surface grooves and a CsA-PLGA composite coating. Normal GDDs, grooved GDDs (G-GDDs), and G-GDDs with a CsA-PLGA composite coating (CsA@G-GDD) were implanted into 18 rabbit eyes (six eyes per group). The intraocular pressure (IOP), bleb survival time, bleb morphology, and anterior chamber reactions were assessed for up to 12 weeks after GDD implantation. The IOPs were compared statistically among the three groups. Bleb morphology was quantified using the Indiana Bleb Appearance Grading Scale. Anterior chamber radiography was performed to check whether the filtrating pathway was blocked, and determine the drainage time and diffusion area of the contrast agent. Hematoxylin and eosin staining and immunohistochemistry were conducted to assess how the GDDs slowed or prevented scar formation. The improved GDDs were successfully prepared and implanted in 18 rabbit eyes without severe surgical complications. Bleb survival time was significantly longer and IOP was significantly lower in the G-GDD and CsA@G-GDD groups compared with the GDD group (all, P < 0.001). Blebs were significantly higher in the CsA@G-GDD group than in the GDD and G-GDD groups (P = 0.003). Anterior chamber radiography revealed more unobstructed filtration channels in the CsA@G-GDD group than in the GDD group (P = 0.032). Postsurgical scar formation was less extensive in the G-GDD and CsA@G-GDD groups than in the GDD group. Compared with the normal GDDs, G-GDDs with a CsA-PLGA coating inhibited postsurgical scar formation and improved the surgical success rate, and might represent an alternative to existing glaucoma filtration devices.

Ultra-narrow band diode lasers with arbitrary pulse shape modulation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ryasnyanskiy, Aleksandr I.; Smirnov, Vadim; Mokhun, Oleksiy; Glebov, Alexei L.; Glebov, Leon B.

2017-03-01

Wideband emission spectra of laser diode bars (several nanometers) can be largely narrowed by the usage of thick volume Bragg gratings (VBGs) recorded in photo-thermo-refractive glass. Such narrowband systems, with GHz-wide emission spectra, found broad applications for Diode Pumped Alkali vapor Lasers, optically pumped rare gas metastable lasers, Spin Exchange Optical Pumping, atom cooling, etc. Although the majority of current applications of narrow line diode lasers require CW operation, there are a variety of fields where operation in a different pulse mode regime is necessary. Commercial electric pulse generators can provide arbitrary current pulse profiles (sinusoidal, rectangular, triangular and their combinations). The pulse duration and repetition rate however, have an influence on the laser diode temperature, and therefore, the emitting wavelength. Thus, a detailed analysis is needed to understand the correspondence between the optical pulse profiles from a diode laser and the current pulse profiles; how the pulse profile and duty cycle affects the laser performance (e.g. the wavelength stability, signal to noise ratio, power stability etc.). We present the results of detailed studies of the narrowband laser diode performance operating in different temporal regimes with arbitrary pulse profiles. The developed narrowband (16 pm) tunable laser systems at 795 nm are capable of operating in different pulse regimes while keeping the linewidth, wavelength, and signal-to-noise ratio (>20 dB) similar to the corresponding CW modules.

Traction suture modification to tongue-in-groove caudal septoplasty.

PubMed

Indeyeva, Y A; Lee, T S; Gordin, E; Chan, D; Ducic, Y

2018-02-01

Caudal septal deviation leads to unfavorable esthetic as well as functional effects on the nasal airway. A modification to the tongue-in-groove (TIG) technique to correct these caudal septal deformities is described. With placement of a temporary suspension suture to the caudal septum, manual traction is applied, assuring that the caudal septum remains in the midline position while it is being secured with multiple through-and-through, trans-columellar and trans-septal sutures. From 2003 to 2016, 148 patients underwent endonasal septoplasty using this modified technique, with excellent functional and cosmetic outcomes and a revision rate of 1.4%. This modified TIG technique replaces the periosteal suture that secures the caudal septum to the midline nasal crest in the original TIG technique. This simplifies the procedure and minimizes the risk of securing the caudal septum off-midline when used in endonasal septoplasty. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Design, Construction, Demonstration and Delivery of an Automated Narrow Gap Welding System.

DTIC Science & Technology

1982-06-29

DESIGN, CONSTRUCTION, DEMONSTRATION AND DELIVERY OF WE DA4I &NARROW GAP CONTRACT NO. NOOGOO-81-C-E923 TO DAVID TAYLOR NAVAL RESEARCH AND DEVELOPMENT...the automated * Narrow Gap welding process, is the narrow (3/8 - inch), square-butt joint *design. This narrow joint greatly reduces the volume of weld...AD-i45 495 DESIGN CONSTRUCTION DEMONSTRATION AiND DELIVERY OF RN 1/j AUrOMATED NARROW GAP WELDING SYSTEMI() CRC AUTOMATIC WELDING CO HOUSTON TX 29

Bayesian Face Recognition and Perceptual Narrowing in Face-Space

PubMed Central

Balas, Benjamin

2012-01-01

During the first year of life, infants’ face recognition abilities are subject to “perceptual narrowing,” the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in developing humans and primates. Though the phenomenon is highly robust and replicable, there have been few efforts to model the emergence of perceptual narrowing as a function of the accumulation of experience with faces during infancy. The goal of the current study is to examine how perceptual narrowing might manifest as statistical estimation in “face space,” a geometric framework for describing face recognition that has been successfully applied to adult face perception. Here, I use a computer vision algorithm for Bayesian face recognition to study how the acquisition of experience in face space and the presence of race categories affect performance for own and other-race faces. Perceptual narrowing follows from the establishment of distinct race categories, suggesting that the acquisition of category boundaries for race is a key computational mechanism in developing face expertise. PMID:22709406

Partial wetting gas-liquid segmented flow microreactor.

PubMed

Kazemi Oskooei, S Ali; Sinton, David

2010-07-07

A microfluidic reactor strategy for reducing plug-to-plug transport in gas-liquid segmented flow microfluidic reactors is presented. The segmented flow is generated in a wetting portion of the chip that transitions downstream to a partially wetting reaction channel that serves to disconnect the liquid plugs. The resulting residence time distributions show little dependence on channel length, and over 60% narrowing in residence time distribution as compared to an otherwise similar reactor. This partial wetting strategy mitigates a central limitation (plug-to-plug dispersion) while preserving the many attractive features of gas-liquid segmented flow reactors.

Parametric Dynamic Load Prediction of a Narrow Gauge Rocket Sled

DTIC Science & Technology

2006-12-01

Monorail λ Compared to Sled Tests.......................................................... 11 Figure 2.1 Application of Vertical λ to a Narrow Gauge sled...Three distinct sled configurations are used: monorail , dual rail wide gauge, and dual rail narrow gauge. Of the three, the narrow gauge...weight and the resulting value was termed λ. Monorail λ factor loading was first documented by Mixon (1971) where a few measured data points were

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.

Behavior of Solvent-Exposed Hydrophobic Groove in the Anti-Apoptotic Bcl-XL Protein: Clues for Its Ability to Bind Diverse BH3 Ligands from MD Simulations

PubMed Central

Sankararamakrishnan, Ramasubbu

2013-01-01

Bcl-XL is a member of Bcl-2 family of proteins involved in the regulation of intrinsic pathway of apoptosis. Its overexpression in many human cancers makes it an important target for anti-cancer drugs. Bcl-XL interacts with the BH3 domain of several pro-apoptotic Bcl-2 partners. This helical bundle protein has a pronounced hydrophobic groove which acts as a binding region for the BH3 domains. Eight independent molecular dynamics simulations of the apo/holo forms of Bcl-XL were carried out to investigate the behavior of solvent-exposed hydrophobic groove. The simulations used either a twin-range cut-off or particle mesh Ewald (PME) scheme to treat long-range interactions. Destabilization of the BH3 domain-containing helix H2 was observed in all four twin-range cut-off simulations. Most of the other major helices remained stable. The unwinding of H2 can be related to the ability of Bcl-XL to bind diverse BH3 ligands. The loss of helical character can also be linked to the formation of homo- or hetero-dimers in Bcl-2 proteins. Several experimental studies have suggested that exposure of BH3 domain is a crucial event before they form dimers. Thus unwinding of H2 seems to be functionally very important. The four PME simulations, however, revealed a stable helix H2. It is possible that the H2 unfolding might occur in PME simulations at longer time scales. Hydrophobic residues in the hydrophobic groove are involved in stable interactions among themselves. The solvent accessible surface areas of bulky hydrophobic residues in the groove are significantly buried by the loop LB connecting the helix H2 and subsequent helix. These observations help to understand how the hydrophobic patch in Bcl-XL remains stable in the solvent-exposed state. We suggest that both the destabilization of helix H2 and the conformational heterogeneity of loop LB are important factors for binding of diverse ligands in the hydrophobic groove of Bcl-XL. PMID:23468841

Pulse stretcher for narrow pulses

NASA Technical Reports Server (NTRS)

Lindsey, R. S., Jr. (Inventor)

1974-01-01

A pulse stretcher for narrow pulses is presented. The stretcher is composed of an analog section for processing each arriving analog pulse and a digital section with logic for providing command signals to the gates and switches in the analog section.

Experimental investigation of circular, flat, grooved and plain steel diaphragms bursting into a 30.5-centimeter-square section

NASA Technical Reports Server (NTRS)

Yamaki, Y.; Rooker, J. R.

1972-01-01

Limited data on the bursting of circular, initially flat, grooved and plain steel diaphragms opening into a 30.5-cm-square section are presented in tabular form. In addition, these data were used to determine values of an empirical constant to be used in a design equation for predicting diaphragm bursting pressures and opening times.

Comparison of liquid chemical sterilization with peracetic acid and ethylene oxide sterilization for long narrow lumens.

PubMed

Alfa, M J; DeGagne, P; Olson, N; Hizon, R

1998-10-01

The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method.

Efficient solar-pumped Nd:YAG laser by a double-stage light-guide/V-groove cavity

NASA Astrophysics Data System (ADS)

Almeida, Joana; Liang, Dawei

2011-05-01

Since the first reported Nd:YAG solar laser, researchers have been exploiting parabolic mirrors and heliostats for enhancing laser output performance. We are now investigating the production of an efficient solar-pumped laser for the reduction of magnesium from magnesium oxide, which could be an alternative solution to fossil fuel. Therefore both high conversion efficiency and excellent beam quality are imperative. By using a single fused silica light guide of rectangular cross section, highly concentrated solar radiation at the focal spot of a stationary parabolic mirror is efficiently transferred to a water-flooded V-groove pump cavity. It allows for the double-pass absorption of pump light along a 4mm diameter, 30mm length, 1.1at% Nd:YAG rod. Optimum pumping parameters and solar laser output power are found through ZEMAXTM non-sequential ray-tracing and LASCADTM laser cavity analysis. 11.0 W of multimode laser output power with excellent beam profile is numerically calculated, corresponding to 6.1W/m2 collection efficiency. To validate the proposed pumping scheme, an experimental setup of the double-stage light-guide/V-groove cavity was built. 78% of highly concentrated solar radiation was efficiently transmitted by the fused silica light guide. The proposed pumping scheme can be an effective solution for enhancing solar laser performances when compared to other side-pump configurations.

Applied anatomy of small branches of the portal vein in transverse groove of hepatic hilum.

PubMed

Yan, Pei-ning; Tan, Wei-feng; Yang, Xin-wei; Zhang, Chuan-sen; Jiang, Xiao-qing

2014-12-01

The objective of this study was to provide the morphological details on small branches of the portal vein in transverse groove of hepatic hilum. According to the surgery significance, the small branches of portal vein in transverse groove of hepatic hilum were named as "Short hepatic portal veins (SHPVs)". SHPVs were minutely dissected in 30 adult cadaveric livers. The number, diameter, length, origin points, and entering liver sites of SHPVs were explored and measured. There were 181 SHPVs in 30 liver specimens, including 46% (83/181) from the left portal vein, 31% (56/181) from the bifurcation, and 23% (42/181) from the right portal vein. At the entering liver sites of SHPVs, 22% (40/181) supplied for segment IV, 9% (17/181) for segment V, 4% (7/181) for segment VI, 23% (41/181) for segment VII, and 42% (76/181) for segment I (caudate lobe). There were 6.0 ± 2.4 branches per liver specimen with range 3-12. The mean diameter of SHPVs was 2.25 ± 0.89 mm. The average length of SHPVs was 4.86 ± 2.12 mm. SHPVs widely existed in each liver specimen. The detailed anatomical study of SHPVs could be useful to avoid damaging the short portal branches during hepatic operations, such as isolated or combined caudate lobectomy.

Seasonal pattern of reverse mounting in the groove-billed ani (Crotophaga sulcirostris)

USGS Publications Warehouse

Bowen, B.S.; Koford, Rolf R.; Vehrencamp, S.L.

1991-01-01

We observed reverse mounting behavior in a color-banded population of Groove-billed Anis (Crotophaga sulcirostris) in Costa Rica. Sex was determined with measurements and laparotomies. Reverse mounting appeared nearly identical to mounting by males. Of 27 mountings in which at least one bird was banded, 15 were reverse mountings. Only reverse mountings (11 observations) were observed in the pre-breeding period. During the breeding season males mounted females in 12 of 16 mountings; one of the reverse mountings followed nest predation. The timing of reverse mounting in anis suggests that it has an adaptive function in courtship. The proximate mechanism may be differential timing between partners in the development of breeding condition or of sexual motivation.

Plastic (wire-combed) grooving of a slip-formed concrete runway overlay at Patrick Henry Airport: An initial evaluation

NASA Technical Reports Server (NTRS)

Marlin, E. C.; Horne, W. B.

1977-01-01

A wire-comb technique is described for transversely grooving the surface of a freshly laid (plastic state) slip-formed concrete overlay installed at Patrick Henry Airport. This method of surface texturing yields better water drainage and pavement skid resistance than that obtained with an older conventional burlap drag concrete surface treatment installed on an adjacent portion of the runway.

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

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

Romero-Hermida, M. I.; Departamento de Física Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla; Romero-Enrique, J. M.

Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N{sub 2}, CO{sub 2}, and O{sub 2}, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO{sub 2} adsorption properties depend mainly on the bulk flue gas thermodynamic conditionsmore » and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO{sub 2} adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO{sub 2} adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO{sub 2} adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO{sub 2} concentrations and low temperatures, the CO{sub 2} adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.« less

Investigating the Temperature Problem in Narrow Line Emitting AGN

NASA Astrophysics Data System (ADS)

Jenkins, Sam; Richardson, Chris T.

2018-06-01

Our research investigates the physical conditions in gas clouds around the narrow line region of AGN. Specifically, we explore the necessary conditions for anomalously high electron temperatures, Te, in those clouds. Our 321 galaxy data set was acquired from SDSS DR14 after requiring S/N > 5.0 in [OIII] 4363 and S/N > 3.0 in all BPT diagram emission lines, to ensure both accurate Te and galaxy classification, with 0.04 < z < 1.0. Interestingly, our data set contained no LINERs. We ran simulations using the simulation code Cloudy, and focused on matching the emission exhibited by the hottest of the 70 AGN in our data set. We used multicore computing to cut down on run time, which drastically improved the efficiency of our simulations. We varied hydrogen density, ionization parameter, and metallicity, Z, only to find these three parameters alone were incapable of recreating anomalously high Te, but successfully matched galaxies showing low- to moderate Te. These highest temperature simulations were at low Z, and were able to facilitate higher temperatures because they avoided the cooling effects of high Z. Our most successful simulations varied Z and grain content, which matched approximately 10% of our high temperature data. Our simulations with the highest grain content produced the highest Te because of the photoelectric heating effect that grains provide, which we confirmed by monitoring each heating mechanism as a function of depth. In the near future, we plan to run simulations varying grain content and ionization parameter in order to study the effects these conditions have on gas cloud Te.

Imidazopyridine/Pyrrole and hydroxybenzimidazole/pyrrole pairs for DNA minor groove recognition.

PubMed

Renneberg, Dorte; Dervan, Peter B

2003-05-14

The DNA binding properties of fused heterocycles imidazo[4,5-b]pyridine (Ip) and hydroxybenzimidazole (Hz) paired with pyrrole (Py) in eight-ring hairpin polyamides are reported. The recognition profile of Ip/Py and Hz/Py pairs were compared to the five-membered ring pairs Im/Py and Hp/Py on a DNA restriction fragment at four 6-base pair recognition sites which vary at a single position 5'-TGTNTA-3', where N = G, C, T, A. The Ip/Py pair distinguishes G.C from C.G, T.A, and A.T, and the Hz/Py pair distinguishes T.A from A.T, G.C, and C.G, affording a new set of heterocycle pairs to target the four Watson-Crick base pairs in the minor groove of DNA.

Effect of Passive Ultrasonic Activation on Organic Tissue Dissolution from Simulated Grooves in Root Canals Using Sodium Hypochlorite with or without Surfactants and EDTA.

PubMed

Estevez, Roberto; Conde, Antonio J; Valencia de Pablo, Oliver; de la Torre, Francisco; Rossi-Fedele, Giampiero; Cisneros, Rafael

2017-07-01

The aim of this study was to evaluate the porcine palatal mucosa dissolution from artificial grooves using a final rinse with sodium hypochlorite (NaOCl) with or without a surfactant or ultrasonic activation (PUI). The root canals of 130 human maxillary central incisors were chemomechanically prepared and the teeth split. A standardized longitudinal intracanal groove was created in 1 of the root halves. One hundred thirty porcine palatal mucosa samples were collected, adapted in order to fit into the grooves, and weighed. The reassembled specimens were randomly divided in 3 experimental groups (n = 40) based on their irrigation protocol (ie, positive pressure [PP] and PUI during 15 [PUI-15] or 30 seconds [PUI-30]) and divided in subgroups according to the NaOCl preparation used: Vista 6% plain (Vista Dental Products, Racine, WI) or Chlor-XTRA (Vista Dental Products) (containing surfactant). An EDTA intermediate rinse was included. Palatal mucosa weights were measured after the assays. The intergroup weight changes were statistically analyzed. Complete dissolution did not occur in any sample. Chlor-XTRA subgroups were associated with increased weight reduction compared with Vista 6% plain subgroups; however, the differences were significant (P < .05) only for PP and PUI-15. PUI-30 increased weight reduction compared with PP for both hypochlorites and PUI-15 using Vista 6% plain (P < .05). PUI-30 with Vista 6% plain performed significantly better than PP with Chlor-XTRA (P < .05). The addition of a surfactant to NaOCl and/or PUI activation increased palatal mucosa dissolution within artificial grooves in the root canal of incisor teeth. PUI agitation was often able to compensate for the absence of surfactants. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Methylene blue binding to DNA with alternating AT base sequence: minor groove binding is favored over intercalation.

PubMed

Rohs, Remo; Sklenar, Heinz

2004-04-01

The results presented in this paper on methylene blue (MB) binding to DNA with AT alternating base sequence complement the data obtained in two former modeling studies of MB binding to GC alternating DNA. In the light of the large amount of experimental data for both systems, this theoretical study is focused on a detailed energetic analysis and comparison in order to understand their different behavior. Since experimental high-resolution structures of the complexes are not available, the analysis is based on energy minimized structural models of the complexes in different binding modes. For both sequences, four different intercalation structures and two models for MB binding in the minor and major groove have been proposed. Solvent electrostatic effects were included in the energetic analysis by using electrostatic continuum theory, and the dependence of MB binding on salt concentration was investigated by solving the non-linear Poisson-Boltzmann equation. We find that the relative stability of the different complexes is similar for the two sequences, in agreement with the interpretation of spectroscopic data. Subtle differences, however, are seen in energy decompositions and can be attributed to the change from symmetric 5'-YpR-3' intercalation to minor groove binding with increasing salt concentration, which is experimentally observed for the AT sequence at lower salt concentration than for the GC sequence. According to our results, this difference is due to the significantly lower non-electrostatic energy for the minor groove complex with AT alternating DNA, whereas the slightly lower binding energy to this sequence is caused by a higher deformation energy of DNA. The energetic data are in agreement with the conclusions derived from different spectroscopic studies and can also be structurally interpreted on the basis of the modeled complexes. The simple static modeling technique and the neglect of entropy terms and of non-electrostatic solute

The narrow pentaquark

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

Diakonov, Dmitri

2007-02-27

The experimental status of the pentaquark searches is briefly reviewed. Recent null results by the CLAS collaboration are commented, and new strong evidence of a very narrow {theta}+ resonance by the DIANA collaboration is presented. On the theory side, I revisit the argument against the existence of the pentaquark - that of Callan and Klebanov - and show that actually a strong resonance is predicted in that approach, however its width is grossly overestimated. A recent calculation gives 2 MeV for the pentaquark width, and this number is probably still an upper bound.

Studies on 405nm blue-violet diode laser with external grating cavity

NASA Astrophysics Data System (ADS)

Li, Bin; Gao, Jun; Zhao, Jun; Yu, Anlan; Luo, Shiwen; Xiong, Dongsheng; Wang, Xinbing; Zuo, Duluo

2016-03-01

Spectroscopy applications of free-running laser diodes (LD) are greatly restricted as its broad band spectral emission. And the power of a single blue-violet LD is around several hundred milliwatts by far, it is of great importance to obtain stable and narrow line-width laser diodes with high efficiency. In this paper, a high efficiency external cavity diode laser (ECDL) with high output power and narrow band emission at 405 nm is presented. The ECDL is based on a commercially available LD with nominal output power of 110 mW at an injection current of 100 mA. The spectral width of the free-running LD is about 1 nm (FWHM). A reflective holographic grating which is installed on a home-made compact adjustable stage is utilized for optical feedback in Littrow configuration. In this configuration, narrow line-width operation is realized and the effects of grating groove density as well as the groove direction related to the beam polarization on the performances of the ECDL are experimentally investigated. In the case of grating with groove density of 3600 g/mm, the threshold is reduced from 21 mA to 18.3 mA or 15.6 mA and the tuning range is 3.95 nm or 6.01 nm respectively when the grating is orientated in TE or TM polarization. In addition, an output beam with a line-width of 30 pm and output power of 92.7 mW is achieved in TE polarization. With these narrow line-width and high efficiency, the ECDL is capable to serve as a light source for spectroscopy application such as Raman scattering and laser induced fluorescence.

Measurement of optical Feshbach resonances in an ideal gas.

PubMed

Blatt, S; Nicholson, T L; Bloom, B J; Williams, J R; Thomsen, J W; Julienne, P S; Ye, J

2011-08-12

Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the optical Feshbach resonance effect in an ultracold gas of bosonic (88)Sr. A systematic measurement of three resonances allows precise determinations of the optical Feshbach resonance strength and scaling law, in agreement with coupled-channel theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. Optical Feshbach resonance could be used to control atomic interactions with high spatial and temporal resolution.

The effect of retentive groove, sandblasting and cement type on the retentive strength of stainless steel crowns in primary second molars--an in vitro comparative study.

PubMed

Veerabadhran, M M; Reddy, V; Nayak, U A; Rao, A P; Sundaram, M A

2012-01-01

This in vitro study was conducted to find out the effect of retentive groove, sand blasting and cement type on the retentive strength of stainless steel crowns in primary second molars. Thirty-two extracted intact human maxillary and mandibular primary second molars were embedded in aluminum blocks utilizing autopolymerising acrylic resin. After tooth preparation, the 3M stainless steel crown was adjusted to the prepared tooth. Then weldable buccal tubes were welded on the buccal and lingual surfaces of each crown as an attachment for the testing machine. A full factorial design matrix for four factors (retentive groove placement on the tooth, cement type, sandblasting and primary second molar) at two levels each was developed and the study was conducted as dictated by the matrix. The lower and upper limits for each factor were without and with retentive groove placement on the tooth, GIC and RMGIC, without and with sandblasting of crown, maxillary and mandibular second primary molar. For those teeth for which the design matrix dictated groove placement, the retentive groove was placed on the middle third of the buccal surface of the tooth horizontally and for those crowns for which sandblasting of the crowns are to be done, sandblasting was done with aluminium oxide with a particle size of 250 mm. The crowns were luted with either GIC or RMGIC, as dictated by the design matrix. Then the retentive strength of each sample was evaluated by means of an universal testing machine. The obtained data was analyzed using ANOVA for statistical analysis of the data and 't'- tests for pairwise comparison. The mean retentive strength in kg/cm 2 stainless steel crowns luted with RMGIC was 19.361 and the mean retentive strength of stainless steel crowns luted with GIC was 15.964 kg/cm 2 with a mean difference of 3.397 kg/cm 2 and was statistically significant. The mean retentive strength in kg/cm 2 of stainless steel crowns, which was not sandblasted, was 18.880 and which was

Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

NASA Technical Reports Server (NTRS)

Singh, K. P.; Garmire, G. P.; Nousek, J.

1985-01-01

The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption.

Galaxy properties from J-PAS narrow-band photometry

NASA Astrophysics Data System (ADS)

Mejía-Narváez, A.; Bruzual, G.; Magris, C. G.; Alcaniz, J. S.; Benítez, N.; Carneiro, S.; Cenarro, A. J.; Cristóbal-Hornillos, D.; Dupke, R.; Ederoclite, A.; Marín-Franch, A.; de Oliveira, C. Mendes; Moles, M.; Sodre, L.; Taylor, K.; Varela, J.; Ramió, H. Vázquez

2017-11-01

We study the consistency of the physical properties of galaxies retrieved from spectral energy distribution (SED) fitting as a function of spectral resolution and signal-to-noise ratio (SNR). Using a selection of physically motivated star formation histories, we set up a control sample of mock galaxy spectra representing observations of the local Universe in high-resolution spectroscopy, and in 56 narrow-band and 5 broad-band photometry. We fit the SEDs at these spectral resolutions and compute their corresponding stellar mass, the mass- and luminosity-weighted age and metallicity, and the dust extinction. We study the biases, correlations and degeneracies affecting the retrieved parameters and explore the role of the spectral resolution and the SNR in regulating these degeneracies. We find that narrow-band photometry and spectroscopy yield similar trends in the physical properties derived, the former being considerably more precise. Using a galaxy sample from the Sloan Digital Sky Survey (SDSS), we compare more realistically the results obtained from high-resolution and narrow-band SEDs (synthesized from the same SDSS spectra) following the same spectral fitting procedures. We use results from the literature as a benchmark to our spectroscopic estimates and show that the prior probability distribution functions, commonly adopted in parametric methods, may introduce biases not accounted for in a Bayesian framework. We conclude that narrow-band photometry yields the same trend in the age-metallicity relation in the literature, provided it is affected by the same biases as spectroscopy, albeit the precision achieved with the latter is generally twice as large as with the narrow-band, at SNR values typical of the different kinds of data.

The extreme ultraviolet spectrograph: A radial groove grating, sounding rocket-borne, astronomical instrument

NASA Technical Reports Server (NTRS)

Wilkinson, Erik; Green, James C.; Cash, Webster

1993-01-01

The design, calibration, and sounding rocket flight performance of a novel spectrograph suitable for moderate-resolution EUV spectroscopy are presented. The sounding rocket-borne instrument uses a radial groove grating to maintain a high system efficiency while controlling the aberrations induced when doing spectroscopy in a converging beam. The instrument has a resolution of approximately 2 A across the 200-330 A bandpass with an average effective area of 2 sq cm. The instrument, called the Extreme Ultraviolet Spectrograph, acquired the first EUV spectra in this wavelength region of the hot white dwarf G191-B2B and the late-type star Capella.

GaAs Solar Cells on V-Grooved Silicon via Selective Area Growth: Preprint

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

Warren, Emily L; Jain, Nikhil; Tamboli, Adele C

Interest in integrating III-Vs onto Si has recently resurged as a promising pathway towards high-efficiency, low-cost tandem photovoltaics. Here, we present a single junction GaAs solar cell grown monolithically on polished Si (001) substrates using V-grooves, selective area growth, and aspect ratio trapping to mitigate defect formation without the use of expensive, thick graded buffers. The GaAs is free of antiphase domains and maintains a relatively low TDD of 4x107 cm-2, despite the lack of a graded buffer. This 6.25 percent-efficient demonstration solar cell shows promise for further improvements to III-V/Si tandems to enable cost-competitive photovoltaics.

Novel Gas Sensor Based on ZnO Nanorod Circular Arrays for C2H5OH Gas Detection.

PubMed

Jianjiao, Zhang; Hongyan, Yue; Erjun, Guo; Shaolin, Zhang; Liping, Wang; Chunyu, Zhang; Xin, Gao; Jing, Chang; Hong, Zhang

2015-03-01

Novel side-heating gas sensor based on ZnO nanorod circular arrays was firstly fabricated by hydrothermal treatment assisted with a kind of simple dip-coating technique. The structure and morphologies of ZnO nanorods were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), respectively. XRD result indicates that the obtained ZnO nanorods have good crystalline with the hexagonal wurtzite structure. SEM result indicates that ZnO nanorod arrays are vertically growth on the surface of ceramic tube of side-heating sensor with controlled diameter and length, narrow size distribution and high orientation. The gas sensing properties of ZnO nanorod circular arrays are also evaluated. Comparative to the sensor based on scattered ZnO nanorods responding to 25 ppm H2, CO, C6H5CH3 and C2H5OH gas, respectively, the sensing values of high orientation gas sensor are generally increased by 5%. This novel sensor has good application promising for the fabrication of cost effective and high performance gas sensors.

The Effect of Divided Attention on Emotion-Induced Memory Narrowing

PubMed Central

Steinmetz, Katherine R. Mickley; Waring, Jill D.; Kensinger, Elizabeth A.

2014-01-01

Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorized to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants’ attentional resources at encoding, by dividing attention, did not affect the emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2), and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across-the-board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond limitations of attentional resources. PMID:24295041

The effect of divided attention on emotion-induced memory narrowing.

PubMed

Mickley Steinmetz, Katherine R; Waring, Jill D; Kensinger, Elizabeth A

2014-01-01

Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorised to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants' attentional resources at encoding by dividing attention did not affect emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2) and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across the board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond the limitations of attentional resources.

M-shaped grating by nanoimprinting: a replicable, large-area, highly active plasmonic surface-enhanced Raman scattering substrate with nanogaps.

PubMed

Zhu, Zhendong; Bai, Benfeng; Duan, Huigao; Zhang, Haosu; Zhang, Mingqian; You, Oubo; Li, Qunqing; Tan, Qiaofeng; Wang, Jia; Fan, Shoushan; Jin, Guofan

2014-04-24

Plasmonic nanostructures separated by nanogaps enable strong electromagnetic-field confinement on the nanoscale for enhancing light-matter interactions, which are in great demand in many applications such as surface-enhanced Raman scattering (SERS). A simple M-shaped nanograting with narrow V-shaped grooves is proposed. Both theoretical and experimental studies reveal that the electromagnetic field on the surface of the M grating can be pronouncedly enhanced over that of a grating without such grooves, due to field localization in the nanogaps formed by the narrow V grooves. A technique based on room-temperature nanoimprinting lithography and anisotropic reactive-ion etching is developed to fabricate this device, which is cost-effective, reliable, and suitable for fabricating large-area nanostructures. As a demonstration of the potential application of this device, the M grating is used as a SERS substrate for probing Rhodamine 6G molecules. Experimentally, an average SERS enhancement factor as high as 5×10⁸ has been achieved, which verifies the greatly enhanced light-matter interaction on the surface of the M grating over that of traditional SERS surfaces. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bayesian Face Recognition and Perceptual Narrowing in Face-Space

ERIC Educational Resources Information Center

Balas, Benjamin

2012-01-01

During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

Sequence-specific binding of counterions to B-DNA

PubMed Central

Denisov, Vladimir P.; Halle, Bertil

2000-01-01

Recent studies by x-ray crystallography, NMR, and molecular simulations have suggested that monovalent counterions can penetrate deeply into the minor groove of B form DNA. Such groove-bound ions potentially could play an important role in AT-tract bending and groove narrowing, thereby modulating DNA function in vivo. To address this issue, we report here 23Na magnetic relaxation dispersion measurements on oligonucleotides, including difference experiments with the groove-binding drug netropsin. The exquisite sensitivity of this method to ions in long-lived and intimate association with DNA allows us to detect sequence-specific sodium ion binding in the minor groove AT tract of three B-DNA dodecamers. The sodium ion occupancy is only a few percent, however, and therefore is not likely to contribute importantly to the ensemble of B-DNA structures. We also report results of ion competition experiments, indicating that potassium, rubidium, and cesium ions bind to the minor groove with similarly weak affinity as sodium ions, whereas ammonium ion binding is somewhat stronger. The present findings are discussed in the light of previous NMR and diffraction studies of sequence-specific counterion binding to DNA. PMID:10639130

The effects of an airborne-particle abrasion and silica-coating on the bond strength between grooved titanium alloy temporary cylinders and provisional veneering materials.

PubMed

Wei, Ann Yu-Chieh; Sharma, Arun B; Watanabe, Larry G; Finzen, Frederick C

2011-03-01

Even though mechanical retentive features, such as grooves, are incorporated into the surface of titanium alloy temporary cylinders, a reliable bond to veneering provisional materials is not always achievable for screw-retained provisional implant restorations. There is insufficient information about the effect of tribochemical silica coating on the bond strength between provisional materials and grooved titanium alloy temporary cylinders. The purpose of this study was to evaluate, in vitro, the effect of an airborne-particle abrasion and silica-coating technique on the bond strength between grooved titanium alloy temporary cylinders and provisional veneering bisphenol-A glycidyl methacrylate and polymethyl methacrylate materials. Forty grooved titanium alloy (Ti-6Al-4V) internal connection implant temporary cylinders were used. A disc of veneering material (7.1 × 3.4 mm) was created around the midsection of each cylinder. Forty specimens were divided into 4 groups (n=10): group NoTxPMMA, no surface treatment and polymethyl methacrylate veneering material; group NoTxBisGMA, no surface treatment and BisGMA veneering material; group AbPMMA, airborne-particle abrasion, silica-coating surface treatment (Rocatec), and polymethyl methacrylate; and group AbBisGMA, airborne-particle abrasion, silica-coating surface treatment (Rocatec), and BisGMA. Each specimen was subjected to ultimate shear load testing at the interface of the veneering material and the temporary cylinder in a universal testing machine at a constant crosshead speed of 5 mm/min. Data were analyzed with a 1-way ANOVA (α=.05) followed by post hoc Student-Newman-Keuls test. Each specimen underwent surface observation with a light microscope at ×40 magnification to compare fracture patterns. Airborne-particle abrasion and silica-coating surface treatment significantly lowered the shear bond strength (P<.05). The type of provisional material did not significantly affect the shear bond strength, with or

Groove Pancreatitis, a Masquerading Yet Distinct Clinicopathological Entity: Analysis of Risk Factors and Differentiation.

PubMed

Oza, Veeral M; Skeans, Jacob M; Muscarella, Peter; Walker, Jon P; Sklaw, Brett C; Cronley, Kevin M; El-Dika, Samer; Swanson, Benjamin; Hinton, Alice; Conwell, Darwin L; Krishna, Somashekar G

2015-08-01

Our objective was to delineate predictive factors differentiating groove pancreatitis (GP) from other lesions involving the head of the pancreas (HOP). A case-control study of patients older than 10 years was performed comparing patients with GP to those with other surgically resected HOP lesions. Thirteen patients with GP (mean ± SD age, 51.9 ± 10.5 years; 11 males [84.6%]), all with a history of smoking (mean, 37.54 ± 17.8 pack-years), were identified. Twelve patients (92.3%) had a history of heavy alcohol drinking (heavy alcohol [EtOH]). The mean lesion size was 2.6 ± 1.1 cm, and the CA 19-9 was elevated (>37 IU/mL) in 5 patients (45.5%). The most common histopathologic condition was duodenal wall cyst with myofibroblastic proliferation and changes of chronic pancreatitis in the HOP.Univariate analysis revealed decreasing age, male sex, weight loss, nausea/vomiting, heavy EtOH, smoking, and a history of chronic pancreatitis were predictive of GP. A multivariate analysis among smokers demonstrated that weight loss (P = 0.006; odds ratio, 11.96; 95% confidence interval, 2.1-70.2), and heavy EtOH (P < 0.001; odds ratio, 82.2; 95% confidence interval, 9.16-738.1) were most predictive of GP. Compared to pancreatic adenocarcinoma (n = 183), weight loss and heavy EtOH remained predictive of GP. Groove pancreatitis in the HOP is associated with a history of heavy EtOH and weight loss. In the absence of these symptoms, it is essential to rule out a malignant lesion.

Resource-assessment perspectives for unconventional gas systems

USGS Publications Warehouse

Schmoker, J.W.

2002-01-01

Concepts are described for assessing those unconventional gas systems that can also be defined as continous accumulations. Continuous gas accumulations exist more or less independently of the water column and do not owe their existence directly to the bouyancy of gas in water. They cannot be represented in terms of individual, countable fields or pools delineated by downdip water contacts. For these reasons, traditional resource-assessment methods based on estimating the sizes and numbers of undiscovered discrete fields cannot not be applied to continuous accumulations. Specialized assessment methods are required. Unconventional gas systems that are also continous accumulations include coalbed methane, basin-centered gas, so-called tight gas, fractured shale (and chalk) gas, and gas hydrates. Deep-basin and bacterial gas systems may or may not be continuous accumulations, depending on their geologic setting. Two basic resource-assessment approaches have been employed for continous accumulations. The first approach is based on estimates of gas in place. A volumetric estimate of total gas in place is commonly coupled with an overall recovery factor to narrow the assessment scope from a treatment of gas volumes residing in sedimentary strata to a prediction of potential additions to reserves. The second approach is based on the production performance of continous gas reservoirs, as shown empirically by wells and reservoir-simulation models. In these methods, production characteristics (as opposed to gas in place) are the foundation for forecasts of potential additions to reserves.