Control pole placement relationships

NASA Technical Reports Server (NTRS)

Ainsworth, O. R.

1982-01-01

Using a simplified Large Space Structure (LSS) model, a technique was developed which gives algebraic relationships for the unconstrained poles. The relationships, which were obtained by this technique, are functions of the structural characteristics and the control gains. Extremely interesting relationships evolve for the case when the structural damping is zero. If the damping is zero, the constrained poles are uncoupled from the structural mode shapes. These relationships, which are derived for structural damping and without structural damping, provide new insight into the migration of the unconstrained poles for the CFPPS.

Electro-dynamic machine, system and method

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

Ouyang, Wen; Ramanan, Varagur

One embodiment is a unique Vernier machine comprising a rotor and a stator. The rotor comprises a back portion and a plurality of permanent magnets. The stator comprises a plurality of ferromagnetic arm structures, a plurality of ferromagnetic pole structures extending from each of the ferromagnetic arm structures in a direction toward the permanent magnets, and a plurality of conductive windings disposed about respective ones of the plurality of ferromagnetic arm structures. The ferromagnetic pole structures are structured to collect magnetic flux from the permanent magnets. The ferromagnetic pole structures of each of said ferromagnetic arm structures are spaced apartmore » from one another according to a non-uniform pattern such that the ferromagnetic pole structures of a given ferromagnetic arm structure have substantially the same angular position relative to the permanent magnets radially opposite from the ferromagnetic pole structures of the given ferromagnetic arm structure.« less

Electron holography study of magnetization behavior in the writer pole of a perpendicular magnetic recording head by a 1 MV transmission electron microscope.

PubMed

Hirata, Kei; Ishida, Yoichi; Akashi, Tetsuya; Shindo, Daisuke; Tonomura, Akira

2012-01-01

The magnetic domain structure of the writer poles of perpendicular magnetic recording heads was studied using electron holography. Although the domain structure of a 100-nm-thick writer pole could be observed with a 300 kV transmission electron microscope, that of the 250-nm-thick writer pole could not be analyzed due to the limited transmission capability of the instrument. On the other hand, the detailed domain structure of the 250-nm-thick writer pole was successfully analyzed by a 1 MV electron microscope using its high transmission capability. The thickness and material dependency of the domain structure of a writer pole were discussed.

Engineering quadratic nonlinear photonic crystals for frequency conversion of lasers

NASA Astrophysics Data System (ADS)

Chen, Baoqin; Hong, Lihong; Hu, Chenyang; Zhang, Chao; Liu, Rongjuan; Li, Zhiyuan

2018-03-01

Nonlinear frequency conversion offers an effective way to extend the laser wavelength range. Quadratic nonlinear photonic crystals (NPCs) are artificial materials composed of domain-inversion structures whose sign of nonlinear coefficients are modulated with desire to implement quasi-phase matching (QPM) required for nonlinear frequency conversion. These structures can offer various reciprocal lattice vectors (RLVs) to compensate the phase-mismatching during the quadratic nonlinear optical processes, including second-harmonic generation (SHG), sum-frequency generation and the cascaded third-harmonic generation (THG). The modulation pattern of the nonlinear coefficients is flexible, which can be one-dimensional or two-dimensional (2D), be periodic, quasi-periodic, aperiodic, chirped, or super-periodic. As a result, these NPCs offer very flexible QPM scheme to satisfy various nonlinear optics and laser frequency conversion problems via design of the modulation patterns and RLV spectra. In particular, we introduce the electric poling technique for fabricating QPM structures, a simple effective nonlinear coefficient model for efficiently and precisely evaluating the performance of QPM structures, the concept of super-QPM and super-periodically poled lithium niobate for finely tuning nonlinear optical interactions, the design of 2D ellipse QPM NPC structures enabling continuous tunability of SHG in a broad bandwidth by simply changing the transport direction of pump light, and chirped QPM structures that exhibit broadband RLVs and allow for simultaneous radiation of broadband SHG, THG, HHG and thus coherent white laser from a single crystal. All these technical, theoretical, and physical studies on QPM NPCs can help to gain a deeper insight on the mechanisms, approaches, and routes for flexibly controlling the interaction of lasers with various QPM NPCs for high-efficiency frequency conversion and creation of novel lasers.

[Pathomorphism of neurotic disorders among military servicemen].

PubMed

Shamreĭ, V K; Marchenko, A A; Abritalin, E Iu; Kurasov, E S; Krasnov, A A

2010-01-01

There were analyzed changes in popularity, structure and clinical peculiarities of neurotic disorders among military servicemen for the period 1986-2006. There were used epidemiological, clinical-archival and clinical-psypathological methods. It was established, that that internosological pathomorphosis of neurosis came out in reduction of their rates in general structure of psychological pathology. Internosological pathomorphosis has found reflection in narrowing of syndromes spectrum and its drift from hypochondriac to anxiety and depressive pole. Dynamic pathomorphosis consisted of less favorable indices of course and outcomes of these disturbances in 1992-1999, and also in reduction of the period of the period from the beginning of illness to hospitalization to a specialized department.

Molecular profiling and sequential somatic mutation shift in hypermutator tumours harbouring POLE mutations.

PubMed

Hatakeyama, Keiichi; Ohshima, Keiichi; Nagashima, Takeshi; Ohnami, Shumpei; Ohnami, Sumiko; Serizawa, Masakuni; Shimoda, Yuji; Maruyama, Koji; Akiyama, Yasuto; Urakami, Kenichi; Kusuhara, Masatoshi; Mochizuki, Tohru; Yamaguchi, Ken

2018-06-07

Defective DNA polymerase ε (POLE) proofreading leads to extensive somatic mutations that exhibit biased mutational properties; however, the characteristics of POLE-mutated tumours remain unclear. In the present study, we describe a molecular profile using whole exome sequencing based on the transition of somatic mutations in 10 POLE-mutated solid tumours that were obtained from 2,042 Japanese patients. The bias of accumulated variations in these mutants was quantified to follow a pattern of somatic mutations, thereby classifying the sequential mutation shift into three periods. During the period prior to occurrence of the aberrant POLE, bare accumulation of mutations in cancer-related genes was observed, whereas PTEN was highly mutated in conjunction with or subsequent to the event, suggesting that POLE and PTEN mutations were responsible for the development of POLE-mutated tumours. Furthermore, homologous recombination was restored following the occurrence of PTEN mutations. Our strategy for estimation of the footprint of somatic mutations may provide new insight towards the understanding of mutation-driven tumourigenesis.

Differences between radiosonde and dropsonde temperature profiles over the Arctic Ocean

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

Skony, S.M.; Kahl, J.D.W.; Zaitseva, N.A.

1994-10-01

The boundary layer structure measured by 402 pairs of approximately collocated radiosonde and dropsonde temperature profiles over the Arctic Ocean during the period 1957-1961 is examined. The radiosonde profiles were obtained at the Russian drifting ice camps `North Pole 7` and `North Pole 8,` and the dropsonde profiles were measured during the United States Air Force `Ptarmigan` series of weather reconnaissance flights. The boundary layer structure is characterized by the features of the low-level tropospheric temperature inversion. The results indicate that the dropsonde soundings, although containing relatively few measurement levels, contain sufficient vertical resolution to characterize the temperature inversion. Systematicmore » differences were noted in wintertime inversion features and near-surface temperatures as measured by dropsondes and radiosondes. These differences are attributed to contrasting temperature lag errors accompanying ascending and descending sensors.« less

Micro-resonator-based electric field sensors with long durations of sensitivity

NASA Astrophysics Data System (ADS)

Ali, Amir R.

2017-05-01

In this paper, we present a new fabrication method for the whispering gallery mode (WGM) micro-sphere based electric field sensor that which allows for longer time periods of sensitivity. Recently, a WGM-based photonic electric field sensor was proposed using a coupled dielectric microsphere-beam. The external electric field imposes an electrtrostriction force on the dielectric beam, deflecting it. The beam, in turn compresses the sphere causing a shift in its WGM. As part of the fabrication process, the PDMS micro-beams and the spheres are curied at high-temperature (100oC) and subsequently poled by exposing to strong external electric field ( 8 MV/m) for two hours. The poling process allows for the deposition of surface charges thereby increasing the electrostriction effect. This methodology is called curing-then-poling (CTP). Although the sensors do become sufficiently sensitive to electric field, they start de-poling after a short period (within 10 minutes) after poling, hence losing sensitivity. In an attempt to mitigate this problem and to lock the polarization for a longer period, we use an alternate methodology whereby the beam is poled and cured simultaneously (curing-while-poling or CWP). The new fabrication method allows for the retention of polarization (and hence, sensitivity to electric field) longer ( 1500 minutes). An analysis is carried out along with preliminary experiments. Results show that electric fields as small as 100 V/m can be detected with a 300 μm diameter sphere sensor a day after poling.

Update to the conventional model for rotational deformation

NASA Astrophysics Data System (ADS)

Ries, J. C.; Desai, S.

2017-12-01

Rotational deformation (also called the "pole tide") is the deformation resulting from the centrifugal effect of polar motion on the solid earth and ocean, which manifests itself as variations in ocean heights, in the gravity field and in surface displacements. The model for rotational deformation assumes a primarily elastic response of the Earth to the centrifugal potential at the annual and Chandler periods and applies body tide Love numbers to the polar motion after removing the mean pole. The original model was conceived when the mean pole was moving (more or less) linearly, largely in response to glacial isostatic adjustment. In light of the significant variations in the mean pole due to present-day ice mass losses, an `appropriately' filtered mean pole was adopted for the conventional model, so that the longer period variations in the mean pole were not included in the rotational deformation model. However, the elastic Love numbers should be applicable to longer period variations as well, and only the secular (i.e. linear) mean pole should be removed. A model for the linear mean pole is recommended based on a linear fit to the IERS C01 time series spanning 1900 to 2015: in milliarcsec, Xp = 55.0+1.677*dt and Yp = 320.5+3.460*dt where dt=(t-t0), t0=2000.0 and assuming a year=365.25 days. The consequences of an updated model for rotational deformation for site motion and the gravity field are illustrated.

Phase-shifted Solc-type filter based on thin periodically poled lithium niobate in a reflective geometry.

PubMed

Ding, Tingting; Zheng, Yuanlin; Chen, Xianfeng

2018-04-30

Configurable narrow bandwidth filters are indispensable components in optical communication networks. Here, we present an easily-integrated compact tunable filtering based on polarization-coupling process in a thin periodically poled lithium niobate (PPLN) in a reflective geometry via the transverse electro-optic (EO) effect. The structure, composed of an in-line polarizer and a thinned PPLN chip, forms a phase-shift Solc-type filter with similar mechanism to defected Bragg gratings. The filtering effect can be dynamically switched on and off by a transverse electric filed. Analogy of electromagnetically induced transparency (EIT) transmission spectrum and electrically controllable group delay is experimentally observed. The mechanism features tunable center wavelength in a wide range with respect to temperature and tunable optical delay to the applied voltage, which may offer another way for optical tunable filters or delay lines.

Fiber grating system used to measure strain in a 22-ft composite utility pole

NASA Astrophysics Data System (ADS)

Udd, Eric; Corona, Kelli; Slattery, Kerry T.; Dorr, Donald J.

1996-05-01

Composite utility poles have significant advantages with respect to wooden utility poles that include superior strength and uniformity, light weight for ease of deployment, the ability to be recycled reducing hazardous waste associated with chemically treated wooden poles, and compatibility with embedded fiber optic sensors allowing structural loads to be monitored. This paper reports tests conducted of fiber optic grating sensors in combination with an overcoupled coupler demodulation system to support structural testing of a 22 foot composite pole.

Tension and compression measurements in composite utility poles using fiber optic grating sensors

NASA Astrophysics Data System (ADS)

Udd, Eric; Corona-Bittick, Kelli; Slattery, Kerry T.; Dorr, Donald J.

1995-04-01

Composite utility poles have the potential to overcome many of the limitations of wooden poles that are currently widely used. Significant advantages include superior strength and uniformity, light weight for ease of deployment, the ability to be recycled reducing hazardous waste associated with chemically treated wooden poles, and compatibility with embedded fiber optic sensors allowing structural loads to be monitored. This paper describes the usage of fiber optic grating sensors to support structural testing of a 22 foot composite pole.

Division site selection in Escherichia coli involves dynamic redistribution of Min proteins within coiled structures that extend between the two cell poles

NASA Astrophysics Data System (ADS)

Shih, Yu-Ling; Le, Trung; Rothfield, Lawrence

2003-06-01

The MinCDE proteins of Escherichia coli are required for proper placement of the division septum at midcell. The site selection process requires the rapid oscillatory redistribution of the proteins from pole to pole. We report that the three Min proteins are organized into extended membrane-associated coiled structures that wind around the cell between the two poles. The pole-to-pole oscillation of the proteins reflects oscillatory changes in their distribution within the coiled structure. We also report that the E. coli MreB protein, which is required for maintaining the rod shape of the cell, also forms extended coiled structures, which are similar to the MreB structures that have previously been reported in Bacillus subtilis. The MreB and MinCDE coiled arrays do not appear identical. The results suggest that at least two functionally distinct cytoskeletal-like elements are present in E. coli and that structures of this type can undergo dynamic changes that play important roles in division site placement and possibly other aspects of the life of the cell.

Shock wave lithotripsy outcomes for lower pole and non-lower pole stones from a university teaching hospital: Parallel group comparison during the same time period

PubMed Central

Geraghty, Robert; Burr, Jacob; Simmonds, Nick; Somani, Bhaskar K.

2015-01-01

Introduction: Shock wave lithotripsy (SWL) is a treatment option for all locations of renal and ureteric stones. We compared the results of SWL for lower pole renal stones with all other non-lower pole renal and ureteric stones during the same time period. Material and Methods: All SWL procedures were carried out as day case procedures by a mobile lithotripter from January 2012 to August 2013. The follow-up imaging was a combination of KUB X-ray or USS. Following SWL treatment, the stone free rate (SFR) was defined as ≤3 mm fragments. Results: A total of 148 patients with a mean age of 62 years underwent 201 procedures. Of the 201 procedures, 93 (46%) were for lower pole stones. The non-lower pole stones included upper pole (n = 36), mid pole (n = 40), renal pelvis (n = 10), PUJ (n = 8), mid ureter (n = 3), upper ureter (n = 5) and a combination of upper, middle and/or lower pole (n = 6). The mean stone size for lower pole stones (7.4 mm; range: 4-16 mm) was slightly smaller than non-lower pole stones (8 mm; range: 4-17 mm). The stone fragmentation was successful in 124 (62%) of patients. However, the SFR was statistically significantly better (P = 0.023) for non-lower pole stones 43 (40%) compared to lower pole stones 23 (25%). There were 9 (4%) minor complications and this was not significantly different in the two groups. Conclusions: Although SWL achieves a moderately high stone fragmentation rate with a low complication rate, the SFR is variable depending on the location of stone and the definition of SFR, with lower pole stones fairing significantly worse than stones in all other locations. PMID:25657543

Shock wave lithotripsy outcomes for lower pole and non-lower pole stones from a university teaching hospital: Parallel group comparison during the same time period.

PubMed

Geraghty, Robert; Burr, Jacob; Simmonds, Nick; Somani, Bhaskar K

2015-01-01

Shock wave lithotripsy (SWL) is a treatment option for all locations of renal and ureteric stones. We compared the results of SWL for lower pole renal stones with all other non-lower pole renal and ureteric stones during the same time period. All SWL procedures were carried out as day case procedures by a mobile lithotripter from January 2012 to August 2013. The follow-up imaging was a combination of KUB X-ray or USS. Following SWL treatment, the stone free rate (SFR) was defined as ≤3 mm fragments. A total of 148 patients with a mean age of 62 years underwent 201 procedures. Of the 201 procedures, 93 (46%) were for lower pole stones. The non-lower pole stones included upper pole (n = 36), mid pole (n = 40), renal pelvis (n = 10), PUJ (n = 8), mid ureter (n = 3), upper ureter (n = 5) and a combination of upper, middle and/or lower pole (n = 6). The mean stone size for lower pole stones (7.4 mm; range: 4-16 mm) was slightly smaller than non-lower pole stones (8 mm; range: 4-17 mm). The stone fragmentation was successful in 124 (62%) of patients. However, the SFR was statistically significantly better (P = 0.023) for non-lower pole stones 43 (40%) compared to lower pole stones 23 (25%). There were 9 (4%) minor complications and this was not significantly different in the two groups. Although SWL achieves a moderately high stone fragmentation rate with a low complication rate, the SFR is variable depending on the location of stone and the definition of SFR, with lower pole stones fairing significantly worse than stones in all other locations.

The period and Q of the Chandler wobble

NASA Technical Reports Server (NTRS)

Smith, M. L.; Dahlen, F. A.

1981-01-01

The calculation of the theoretical period of the Chandler wobble is extended to account for the non-hydrostatic portion of the earth's equatorial bulge and the effect of the fluid core upon the lengthening of the period due to the pole tide. The theoretical period of a realistic perfectly elastic earth with an equilibrium pole tide is found to be 426.7 sidereal days, which is 8.5 days shorter than the observed period of 435.2 days. Using Rayleigh's principle for a rotating earth, this discrepancy is exploited together with the observed Chandler Q to place constraints on the frequency dependence of mantle anelasticity. In all cases these limits arise from exceeding the 68 percent confidence limits of + or - 2.6 days in the observed period. Since slight departures from an equilibrium pole tide affect the Q much more strongly than the period, these limits are believed to be robust.

Design and evaluation of large scale pultruded fiberglass tubular structures

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

O`Toole, B.J.

1994-12-31

Large solid wood structures have been used in structural applications such as utility poles and marine pilings for a long time. A pultruded fiberglass reinforced polymer composite utility pole has been designed by the Composite Power Corporation of Las Vegas, Nevada which meets or exceeds the wood pole strength standards. This type of pole has many advantages over traditional wood, metal or concrete poles including: lighter weight, easier to climb and service, better dielectric and fire resistance properties, and it is more environmentally sound than treated wood poles. Utility crossarms, other attachments, and climbing devices are secured to grooves whichmore » run the entire length of the pole so there is no need to drill holes or wear spiked boots which would compromise the strength of the pole. Bending and torsion experiments have been conducted to determine if the present design meets the strength requirements of a forty foot Class one wood pole. Initial results of the composite pole tests showed a 17 percent advantage in bending strength, a 449 percent advantage in strength due to a vertical load applied to a crossarm, and a 43 percent advantage in twisting strength. Plans for further material characterization experiments and detailed stress and failure analysis are discussed.« less

Surface spontaneous parametric down-conversion.

PubMed

Perina, Jan; Luks, Antonín; Haderka, Ondrej; Scalora, Michael

2009-08-07

Surface spontaneous parametric down-conversion is predicted as a consequence of continuity requirements for electric- and magnetic-field amplitudes at a discontinuity of chi;{(2)} nonlinearity. A generalization of the usual two-photon spectral amplitude is suggested to describe this effect. Examples of nonlinear layered structures and periodically poled nonlinear crystals show that surface contributions to spontaneous down-conversion can be important.

Electrical Transfer Function and Poling Mechanisms for Nonlinear Optical Polymer Modulators

NASA Technical Reports Server (NTRS)

Watson, Michael Dale

2004-01-01

Electro-Optic Polymers hold great promise in increased electro-optic coefficients as compared to their inorganic corollaries. Many researchers have focused on quantum chemistry to describe how the dipoles respond to temperature and electric fields. Much work has also been done for single layer films to confirm these results. For optical applications, waveguide structures are utilized to guide the optical waves in 3 layer stacks. Electrode poling is the only practical poling method for these structures. This research takes an electrical engineering approach to develop poling models and electrical and optical transfer functions of the waveguide structure. The key aspect of the poling model is the large boundary charge density deposited during the poling process. The boundary charge density also has a large effect on the electrical transfer function which is used to explain the transient response of the system. These models are experimentally verified. Exploratory experiment design is used to study poling parameters including time, temperature, and voltage. These studies verify the poling conditions for CLDX/APC and CLDZ/APEC guest host electro optic polymer films in waveguide stacks predicted by the theoretical developments.

29 CFR 1926.953 - Material handling.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Material handling. (a) Unloading. Prior to unloading steel, poles, cross arms and similar material, the.... During framing operations, employees shall not work under a pole or a structure suspended by a crane, A-frame or similar equipment unless the pole or structure is adequately supported. (g) Attaching the load...

29 CFR 1926.953 - Material handling.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Material handling. (a) Unloading. Prior to unloading steel, poles, cross arms and similar material, the.... During framing operations, employees shall not work under a pole or a structure suspended by a crane, A-frame or similar equipment unless the pole or structure is adequately supported. (g) Attaching the load...

29 CFR 1926.953 - Material handling.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Material handling. (a) Unloading. Prior to unloading steel, poles, cross arms and similar material, the.... During framing operations, employees shall not work under a pole or a structure suspended by a crane, A-frame or similar equipment unless the pole or structure is adequately supported. (g) Attaching the load...

Efficient green light generation by Q-switched Nd: YAG laser in periodically poled potassium titanyl phosphate crystal

NASA Astrophysics Data System (ADS)

Zhang, Shuanggen; Guo, Wengang; Lv, Fuyun

2014-07-01

A PPKTP crystal was used to efficient green emission. Spectrum characteristics of FF and SH wave was analyzed, and phase-matching wavelength shift results from thermally-induced poling period shift. A conversion efficiency of 26.1% can be achieved.

Strength of single-pole utility structures

Treesearch

Ronald W. Wolfe

2006-01-01

This section presents three basic methods for deriving and documenting Rn as an LTL value along with the coefficient of variation (COVR) for single-pole structures. These include the following: 1. An empirical analysis based primarily on tests of full-sized poles. 2. A theoretical analysis of mechanics-based models used in...

Bandwidth tunable THz wave generation in large-area periodically poled lithium niobate.

PubMed

Zhang, Caihong; Avetisyan, Yuri; Glosser, Andreas; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi

2012-04-09

A new scheme of optical rectification (OR) of femtosecond laser pulses in a periodically poled lithium niobate (PPLN) crystal, which generates high energy and bandwidth tunable multicycle THz pulses, is proposed and demonstrated. We show that the number of the oscillation cycles of the THz electric field and therefore bandwidth of generated THz spectrum can easily and smoothly be tuned from a few tens of GHz to a few THz by changing the pump optical spot size on PPLN crystal. The minimal bandwidth is 17 GHz that is smallest ever of reported in scheme of THz generation by OR at room temperature. Similar to the case of Cherenkov-type OR in single-domain LiNbO₃, the spectrum of THz generation extends from 0.1 THz to 3 THz when laser beam is focused to a size close to half-period of PPLN structure. The energy spectral density of narrowband THz generation is almost independent of the bandwidth and is typically 220 nJ/THz for ~1 W pump power at 1 kHz repetition rate.

Photometric geodesy of main-belt asteroids. II - Analysis of lightcurves for poles, periods, and shapes

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R.

1988-01-01

The assumption that asteroids can be modeled as smooth, featureless, triaxial ellipsoids that rotate about their shortest axes is presently used to study all but one of the 26 asteroids treated in the Weidenschilling et al. (1987) 'photometric geodesy' program. Rotational poles derived from three independent methods are used to determine each asteroid's sidereal period and triaxial ellipsoid axial ratios, together with their associated photometric parameters. The asteroids appear to have rotational poles that do not lie along their orbital planes.

Post-earthquake relaxation using a spectral element method: 2.5-D case

USGS Publications Warehouse

Pollitz, Fred

2014-01-01

The computation of quasi-static deformation for axisymmetric viscoelastic structures on a gravitating spherical earth is addressed using the spectral element method (SEM). A 2-D spectral element domain is defined with respect to spherical coordinates of radius and angular distance from a pole of symmetry, and 3-D viscoelastic structure is assumed to be azimuthally symmetric with respect to this pole. A point dislocation source that is periodic in azimuth is implemented with a truncated sequence of azimuthal order numbers. Viscoelasticity is limited to linear rheologies and is implemented with the correspondence principle in the Laplace transform domain. This leads to a series of decoupled 2-D problems which are solved with the SEM. Inverse Laplace transform of the independent 2-D solutions leads to the time-domain solution of the 3-D equations of quasi-static equilibrium imposed on a 2-D structure. The numerical procedure is verified through comparison with analytic solutions for finite faults embedded in a laterally homogeneous viscoelastic structure. This methodology is applicable to situations where the predominant structure varies in one horizontal direction, such as a structural contrast across (or parallel to) a long strike-slip fault.

Dual-frequency continuous wave optical parametric oscillator

NASA Astrophysics Data System (ADS)

Sun, Bingjie; Wang, Xin; Yang, Suhui; Li, Kun

2018-01-01

This article shows a dual-frequency OPO with multi-grating (28.5-31.5 μm) periodically poled MgO:LiNbO3 (MgO:PPLN) pumped by a dual-frequency continuous wave at 1.064 μm. The wavelengths of idler and signal varying versus temperature at different periods of inverted domains were numerical simulated. It proves that as the temperature rises, or as the poling period increases, the idler wavelength shortens and signal wavelength lengthens. The pump is a 30 W dual-frequency fiber laser MOPA with beat note frequency varying from 125 MHz to 175 MHz. The pump threshold of the bow-tie ring cavity OPO was 3 W. An average dual-frequency idler output power of 2.6 W was obtained when the pump power was 17.2 W at 45 °C. The idler wavelength was 3.4 μm when the poling period was 30.5 μm. The idler wavelength could be tuned from 2.9 μm to 3.9 μm by changing the temperature and the poling period, and the beat note frequency was proved to be equal to that of the pump.

A 2 Tesla Full Scale High Performance Periodic Permanent Magnet Model for Attractive (228 KN) and repulsive Maglev

NASA Technical Reports Server (NTRS)

Stekly, Z. J. J.; Gardner, C.; Domigan, P.; Baker, J.; Hass, M.; McDonald, C.; Wu, C.; Farrell, R. A.

1996-01-01

Two 214.5 cm. long high performance periodic (26 cm period) permanent magnet half-assemblies were designed and constructed for use as a wiggler using Nd-B-Fe and vanadium permendur as hard and soft magnetic materials by Field Effects, a division of Intermagnetics General Corporation. Placing these assemblies in a supporting structure with a 2.1 cm pole to pole separation resulted in a periodic field with a maximum value of 2.04 T. This is believed to be the highest field ever achieved by this type of device. The attractive force between the two 602 kg magnet assemblies is 228 kN, providing enough force for suspension of a 45,500 kg vehicle. If used in an attractive maglev system with an appropriate flat iron rail, one assembly will generate the same force with a gap of 1.05 cm leading to a lift to weight ratio of 38.6, not including the vehicle attachment structure. This permanent magnet compares well with superconducting systems which have lift to weight ratios in the range of 5 to 10. This paper describes the magnet assemblies and their measured magnetic performance. The measured magnetic field and resulting attractive magnetic force have a negative spring characteristic. Appropriate control coils are necessary to provide stable operation. The estimated performance of the assemblies in a stable repulsive mode, with eddy currents in a conducting guideway, is also discussed.

Simulations of electrically induced particle structuring on spherical drop surface

NASA Astrophysics Data System (ADS)

Hu, Yi; Vlahovska, Petia; Miksis, Michael

2016-11-01

Recent experiments (Ouriemi and Vlahovska, 2014) show intriguing surface patterns when a uniform electric field is applied to a droplet covered with colloidal particles. Depending on the particle properties and the electrical field intensity, particles organize into an equatorial belt, pole-to-pole chains, or dynamic vortices. Here we present a model to simulate the collective particle dynamics, which accounts for the electrohydrodynamic flow and particle dielectrophoresis due to the non-uniformity of local electrical field. In stronger electric fields, particles are expected to undergo Quincke rotation, inducing rotating clusters through inter-particle hydrodynamical interaction. We discuss how the field intensity influences the width, orientation and periodicity of the particle clusters. Our results provide insight into the various particle assembles discovered in the experiments.

On the Physical Realizability of Broad-Band Equivalent Circuits for Wire Loop and Dipole Antennas.

DTIC Science & Technology

1979-05-01

found numerically, the task of grouping the poles by eigenmodes is much more difficult. For a complex object where the poles are experimentally . ived...structure is PR or can be made PR, then when all the poles for the structure are grouped the low frequency non -PR character of the higher poles are...the quarter point of the wire, some non -PR results are discovered. These groupings are indicated in Figures 45 through 49. The postulated eigenmode

Operational forest stream crossings effects on water quality in the Virginia Piedmont

Treesearch

Wallace M. Aust; Matthew B. Carroll; M. Chad Bolding; Andy Dolloff

2011-01-01

Water quality indices were examined for paired upstream and downstream samples for 23 operational stream crossings and approaches during four periods. Stream crossings were (1) portable bridges (BRIDGE), (2) culverts backfilled with poles (POLE), (3) culverts with earth backfill (CULVERT), and (4) reinforced fords (FORD). The four operational periods were (1) prior to...

Magnetic field adjustment structure and method for a tapered wiggler

DOEpatents

Halbach, Klaus

1988-03-01

An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.

Magnetic field adjustment structure and method for a tapered wiggler

DOEpatents

Halbach, Klaus

1988-01-01

An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.

Imaging and engineering the nanoscale-domain structure of a Sr0.61Ba0.39Nb2O6 crystal using a scanning force microscope

NASA Astrophysics Data System (ADS)

Terabe, K.; Takekawa, S.; Nakamura, M.; Kitamura, K.; Higuchi, S.; Gotoh, Y.; Gruverman, A.

2002-09-01

We have investigated the ferroelectric domain structure formed in a Sr0.61Ba0.39Nb2O6 single crystal by cooling the crystal through the Curie point. Imaging the etched surface structure using a scanning force microscope (SFM) in both the topographic mode and the piezoresponse mode revealed that a multidomain structure of nanoscale islandlike domains was formed. The islandlike domains could be inverted by applying an appropriate voltage using a conductive SFM tip. Furthermore, a nanoscale periodically inverted-domain structure was artificially fabricated using the crystal which underwent poling treatment.

Pole pulling apparatus and method

DOEpatents

McIntire, Gary L.

1989-01-01

An apparatus for removal of embedded utility-type poles which removes the poles quickly and efficiently from their embedded position without damage to the pole or surrounding structures. The apparatus includes at least 2 piston/cylinder members equally spaced about the pole, and a head member affixed to the top of each piston. Elongation of the piston induces rotation of the head into the pole to increase the gripping action and reduce slippage. Repeated actuation and retraction of the piston and head member will "jack" the pole from its embedded position.

A comparative analysis of permanent magnet-type bearingless synchronous motors for fully magnetically levitated rotors

NASA Astrophysics Data System (ADS)

Charpentier, J. F.; Lemarquand, G.

1998-06-01

Radial instability of synchronous motors is important data to design magnetic bearings. Moreover, original motor structures must be proposed to decrease the instability. In this article, four structures with a permanent magnet rotor, six poles, and the same main mechanical dimensions are analyzed and compared. The first concerns a rotor with six tiles of permanent magnets radially magnetized and adhered to an iron core. The second is a rotor with six axial permanent magnets tangentially magnetized and separated by iron pole pieces, where the shaft is amagnetic. The third design proposes a rotor with six contiguous tiles of permanent magnets tangentially magnetized and an amagnetic shaft. In the fourth structure each north pole is made up of two contiguous tiles of permanent magnets tangentially magnetized in opposite direction and each south pole is made up of an iron pole piece. The shaft of this structure is amagnetic. The stator structure and the currents in stator windings produce a six poles flux distribution. A finite element method program is employed to study the forces and the torques. The four structures are designed to provide the same motor performance (torque). The radial instability is modeled by outcentering the rotor. The relationships between the radial force and the type of structure are analyzed. The result is that the third structure is the best solution for fully magnetically levitated rotors. It has a small instability and does not generate any disturbing force whose frequency is the double of the rotation frequency. This structure also has good properties to be used as a radial magnetic bearing.

Wind Stress Forcing of the North Sea "Pole Tide"

NASA Technical Reports Server (NTRS)

OConnor, William P.; Chao, Benjamin Fong; Zheng, Dawei; Au, Andrew Y.

1998-01-01

We conducted numerical simulations of the wind-forcing of the sea level variations in the North Sea using a barotropic ocean model with realistic geography, bathymetry, and boundary conditions, to examine the forcing of the 14-month "pole tide" which is known to be strong along the Denmark- Netherlands coast. The simulation input is the monthly-mean surface wind stress field from the National Centers for Environmental Prediction (NCEP) reanalysis for the 40-year period 1958-1997. The output sea level response was then compared with 10 coastal tide gauge records from the Permanent Service for Mean Sea Level (PSMSL). Besides the strong seasonal variations, several prominent quasi-periodicities exist at around 7 years, 3 years, 14 months, 9 months, and 6.5 months. Correlation and spectral analyses show remarkable agreement between the model output and the observations, particularly in the 14-month, or Chandler period band. The latter indicates that the enhanced pole tide found in the North Sea along the Denmark-Netherlands coast is actually the coastal setup response to wind stress forcing with a periodicity of 14 months. We find no need to invoke a geophysical explanation involving resonance-enhancement of pole tide in the North Sea to explain the observations.

Secular obliquity variations for Ceres

NASA Astrophysics Data System (ADS)

Bills, Bruce; Scott, Bryan R.; Nimmo, Francis

2016-10-01

We have constructed secular variation models for the orbit and spin poles of the asteroid (1) Ceres, and used them to examine how the obliquity, or angular separation between spin and orbit poles, varies over a time span of several million years. The current obliquity is 4.3 degrees, which means that there are some regions near the poles which do not receive any direct Sunlight. The Dawn mission has provided an improved estimate of the spin pole orientation, and of the low degree gravity field. That allows us to estimate the rate at which the spin pole precesses about the instantaneous orbit pole.The orbit of Ceres is secularly perturbed by the planets, with Jupiter's influence dominating. The current inclination of the orbit plane, relative to the ecliptic, is 10.6 degrees. However, it varies between 7.27 and 11.78 degrees, with dominant periods of 22.1 and 39.6 kyr. The spin pole precession rate parameter has a period of 205 kyr, with current uncertainty of 3%, dominated by uncertainty in the mean moment of inertia of Ceres.The obliquity varies, with a dominant period of 24.5 kyr, with maximum values near 26 degrees, and minimum values somewhat less than the present value. Ceres is currently near to a minimum of its secular obliquity variations.The near-surface thermal environment thus has at least 3 important time scales: diurnal (9.07 hours), annual (4.60 years), and obliquity cycle (24.5 kyr). The annual thermal wave likely only penetrates a few meters, but the much long thermal wave associated with the obliquity cycle has a skin depth larger by a factor of 70 or so, depending upon thermal properties in the subsurface.

Is flexible ureterorenoscopy and laser lithotripsy the new gold standard for lower pole renal stones when compared to shock wave lithotripsy: Comparative outcomes from a University hospital over similar time period.

PubMed

Burr, Jacob; Ishii, Hiro; Simmonds, Nick; Somani, Bhaskar K

2015-01-01

Renal lower pole stones pose difficulty in management due to anatomical variation, stone size, hardness and patient demographics. Flexible ureterorenoscopy and laser lithotripsy (FURSL) and shock wave lithotripsy (SWL) are preferred for stones 1-2 cm in size. We wanted to compare the outcomes of FURSL and SWL for lower pole stones during the same time period. All patients who were treated for lower pole stones with FURSL and SWL during a 19-month period were included. The stone free rate (SFR) was defined as ≤3 mm fragments on follow-up imaging or stone free endoscopically. Data was recorded in an excel spreadsheet with SPSS version 21 used for statistical analysis. A total of 161 lower pole procedures were done (93 SWL and 63 FURSL). The mean stone size for SWL (7.4 mm; range: 4-16 mm) was significantly smaller than for FURSL (13.4 mm; 4-53 mm). The mean operating time and hospital stay for FURSL was 65 minutes (range: 30-160 minutes) and 0.5 days (range: 0-7 days) respectively. The SFR was significantly better (p <0.001) for FURSL (n = 63, 93%) compared to SWL (n = 23, 25%). There were 4 (6%) complications (3 Clavien II and 1 Clavien I) in the FURSL group (2 urosepsis, 1 UTI and 1 stent pain). Three patients in the SWL group (Clavien I) were readmitted with renal colic but there were no other complications. FURSL for lower pole stones seems to be a much better alternative than SWL with a high SFR even for larger stones and seems to be the new gold standard for lower pole stone management.

Photometric geodesy of main-belt asteroids. IV - An updated analysis of lightcurves for poles, periods, and shapes

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R.

1991-01-01

The Drummond et al. (1988) analysis of main-belt asteroids is presently extended, using three independent methods to derive poles, periods, phase functions, and triaxial ellipsoid shapes from lightcurve maxima and minima. This group of 26 asteroids is also reinvestigated with a view to the distributions of triaxial shapes and obliquity distributions. Poles weakly tend to avoid asteroid orbital planes; a rough-smooth dichotomization appears to be justified by the persistence of two solar phase angle-amplitude relations. Seven of the objects may be Jacobi ellipsoids if axial ratios are slightly exaggerated by a systematic effect of the analytical method employed.

Decrease of summer tropospheric ozone concentrations in Antarctica

NASA Technical Reports Server (NTRS)

Schnell, R. C.; Stone, R. S.; Liu, S. C.; Oltmans, S. J.; Hofmann, D. J.

1991-01-01

It is shown here that surface ozone concentrations at the South Pole in the austral summer decreased by 17 percent over the period 1976-90. Over the same period, solar irradiance at the South Pole in January and February decreased by 7 percent as a result of a 25 percent increase in cloudiness. It is suggested that the trend in the summer ozone concentrations is caused by enhanced photochemical destruction of ozone in the lower troposphere caused by the increased penetration of UV radiation associated with stratospheric ozone depletion, coupled with enhanced transport of ozone-poor marine air from lower latitudes to the South Pole.

Poling of PVDF matrix composites for integrated structural load sensing

NASA Astrophysics Data System (ADS)

Haghiashtiani, Ghazaleh; Greminger, Michael A.; Zhao, Ping

2014-03-01

The purpose of this study is to create and evaluate a smart composite structure that can be used for integrated load sensing and structural health monitoring. In this structure, PVDF films are used as the matrix material instead of epoxy resin or other thermoplastics. The reinforcements are two layers of carbon fiber with one layer of Kevlar separating them. Due to the electrical conductivity properties of carbon fiber and the dielectric effect of Kevlar, the structure acts as a capacitor. Furthermore, the piezoelectric properties of the PVDF matrix can be used to monitor the response of the structure under applied loads. In order to exploit the piezoelectric properties of PVDF, the PVDF material must be polarized to align the dipole moments of its crystalline structure. The optimal condition for poling the structure was found by performing a 23 factorial design of experiment (DoE). The factors that were studied in DoE were temperature, voltage, and duration of poling. Finally, the response of the poled structure was monitored by exposing the samples to an applied load.

Detection and Classification of Pole-Like Objects from Mobile Mapping Data

NASA Astrophysics Data System (ADS)

Fukano, K.; Masuda, H.

2015-08-01

Laser scanners on a vehicle-based mobile mapping system can capture 3D point-clouds of roads and roadside objects. Since roadside objects have to be maintained periodically, their 3D models are useful for planning maintenance tasks. In our previous work, we proposed a method for detecting cylindrical poles and planar plates in a point-cloud. However, it is often required to further classify pole-like objects into utility poles, streetlights, traffic signals and signs, which are managed by different organizations. In addition, our previous method may fail to extract low pole-like objects, which are often observed in urban residential areas. In this paper, we propose new methods for extracting and classifying pole-like objects. In our method, we robustly extract a wide variety of poles by converting point-clouds into wireframe models and calculating cross-sections between wireframe models and horizontal cutting planes. For classifying pole-like objects, we subdivide a pole-like object into five subsets by extracting poles and planes, and calculate feature values of each subset. Then we apply a supervised machine learning method using feature variables of subsets. In our experiments, our method could achieve excellent results for detection and classification of pole-like objects.

A Self-Contained Pole Syringe Array for Closed-Interval Water Sampling.

DTIC Science & Technology

1982-10-19

L AD-R12l 265 R SELF-CONTAINED POLE SYRINGE ARRAY FOR CLOSDITRR Va WATER SANPLING4U) NAVAL RESEARCH LAB WASHINGTON DC I R E PELLENBARG ET AL. 19 OCT...PERIOD COVERED A SELF-CONTAINED POLE SYRINGE ARRAY FOR Interim report on one phase of CLOSED-INTERVAL WATER SAMPLING an NRL problem. 6. PERFORMING ORG...1473 EDITION OF I NOv ,, IS OMSOLCT S/N 0102-014- 6601 SECURITY CLASSIFICATION OF THIS PAGE (Wm Dle Et ere d A SELF-CONTAINED POLE SYRINGE ARRAY FOR

In-situ poling and structurization of piezoelectric particulate composites.

PubMed

Khanbareh, H; van der Zwaag, S; Groen, W A

2017-11-01

Composites of lead zirconate titanate particles in an epoxy matrix are prepared in the form of 0-3 and quasi 1-3 with different ceramic volume contents from 10% to 50%. Two different processing routes are tested. Firstly a conventional dielectrophoretic structuring is used to induce a chain-like particle configuration, followed by curing the matrix and poling at a high temperature and under a high voltage. Secondly a simultaneous combination of dielectrophoresis and poling is applied at room temperature while the polymer is in the liquid state followed by subsequent curing. This new processing route is practiced in an uncured thermoset system while the polymer matrix still possess a relatively high electrical conductivity. Composites with different degrees of alignment are produced by altering the magnitude of the applied electric field. A significant improvement in piezoelectric properties of quasi 1-3 composites can be achieved by a combination of dielectrophoretic alignment of the ceramic particles and poling process. It has been observed that the degree of structuring as well as the functional properties of the in-situ structured and poled composites enhance significantly compared to those of the conventionally manufactured structured composites. Improving the alignment quality enhances the piezoelectric properties of the particulate composites.

Development of Mini-pole Superconducting Undulator

NASA Astrophysics Data System (ADS)

Jan, J. C.; Hwang, C. S.; Lin, P. H.; Chang, C. H.; Lin, F. Y.

2007-01-01

A mini-pole superconducting undulator with a 15mm period length (SU15) was developed at the National Synchrotron Radiation Research Center (NSRRC). The coil was wound by a superconducting (SC) NbTi wire with small dimensions and low Cu/SC ratio. The design field strength of SU15 with 158turns/pole was 1.4T at 215A, and the magnet gap was 5.6 mm. Extra trim coils and poles are mounted on the main iron pole. The trim coils directly compensate for the strength error of the peak field. The prototype racetrack iron pole was fabricated via electric discharge machining to produce a complete set of 40-poles. The coil was impregnated by epoxy and wrapped in Kapton to maintain insulation between coil and iron pole. A substitution beam duct was built and assembled with the magnet array and tested in the test Dewar. The conceptual design of bath liquid helium (LHe) cryostat has to tolerate more image current and radiation heating on the beam duct.

Lunar Obliquity History Revisited

NASA Astrophysics Data System (ADS)

Siegler, M.; Bills, B.; Paige, D.

2007-12-01

In preparation for a LRO (Lunar Reconnaissance Orbiter) related study of possible lunar polar volatiles, we re- examined the lunar orbital and rotational history, with primary focus on the obliquity history of the Moon. Though broad models have been made of lunar obliquity, a cohesive obliquity history was not found. We report on a new model of lunar obliquity including secular changes in inclination of the lunar orbit, tidal dissipation, lunar moments of inertia, and details for periods outside of the stable configurations known as Cassini states. For planets, the obliquity, or angle between the spin and orbit poles, is the dominant control on incident solar radiation. For planetary satellites, the radiation pattern can be more complex, as it depends on the mutual inclinations of three poles; the satellite spin and orbit poles, and the planetary heliocentric orbit pole. Presently, the lunar spin pole and orbit pole co-precess about the ecliptic pole, in a stable situation known as a Cassini state. As a result, permanently shadowed regions near the poles are expected to exist and act as cold traps, retaining water or other volatiles delivered to the surface by comets, solar wind, or via outgassing of the lunar interior. However, tidally driven secular changes in the lunar semimajor axis cause changes in precession rates of the spin and orbit poles, and thereby alter or destabilize the Cassini states. Only one prograde Cassini state exists at present (state 2). In the standard Cassini state model of Ward [1975], two other such states would have existed in the past (states 1 and 4) with the Moon starting in the low obliquity state 1, and remaining there until states 1 and 4 merged and disappear, at roughly half the present Earth-Moon distance. At that point, the Moon transitioned into the currently occupied state 2, and briefly attained very high obliquity values during the transition, and then stayed in state 2 until the present. If correct, this model implies that the transition from state 1 to state 2 is the most important event in the histories of lunar obliquity and polar volatiles, as it separates two periods in which current lunar cold traps could have existed with a period of high polar insolation which could have mobilized volatiles into space or to greater depths in the lunar near surface. If incorrect, lunar cold traps may prove only a very recent phenomenon. By including secular orbit changes, our model should help determine if this Cassini state stability really dominated in the past and allow detailed examination of extra-Cassini state periods.

High-power, continuous-wave, single-frequency, all-periodically-poled, near-infrared source.

PubMed

Devi, Kavita; Chaitanya Kumar, S; Ebrahim-Zadeh, M

2012-12-15

We report a high-power, single-frequency, continuous-wave (cw) source tunable across 775-807 nm in the near-infrared, based on internal second harmonic generation (SHG) of a cw singly-resonant optical parametric oscillator (OPO) pumped by a Yb-fiber laser. The compact, all-periodically-poled source employs a 48-mm-long, multigrating MgO doped periodically poled lithium niobate (MgO:PPLN) crystal for the OPO and a 30-mm-long, fan-out grating MgO-doped stoichiometric periodically poled lithium tantalate (MgO:sPPLT) crystal for intracavity SHG, providing as much as 3.7 W of near-infrared power at 793 nm, together with 4 W of idler power at 3232 nm, at an overall extraction efficiency of 28%. Further, the cw OPO is tunable across 3125-3396 nm in the idler, providing as much as 4.3 W at 3133 nm with >3.8  W over 77% of the tuning range together with >3  W of near-infrared power across 56% of SHG tuning range, in high-spatial beam-quality with M2<1.4. The SHG output has an instantaneous linewidth of 8.5 MHz and exhibits a passive power stability better than 3.5% rms over more than 1 min.

Microwave active filters based on coupled negative resistance method

NASA Astrophysics Data System (ADS)

Chang, Chi-Yang; Itoh, Tatsuo

1990-12-01

A novel coupled negative resistance method for building a microwave active bandpass filter is introduced. Based on this method, four microstrip line end-coupled filters were built. Two are fixed-frequency one-pole and two-pole filters, and two are tunable one-pole and two-pole filters. In order to broaden the bandwidth of the end-coupled filter, a modified end-coupled structure is proposed. Using the modified structure, an active filter with a bandwidth up to 7.5 percent was built. All of the filters show significant passband performance improvement. Specifically, the passband bandwidth was broadened by a factor of 5 to 20.

Ferroelectric domain building blocks for photonic and nonlinear optical microstructures in LiNbO3

NASA Astrophysics Data System (ADS)

Zisis, G.; Ying, C. Y. J.; Soergel, E.; Mailis, S.

2014-03-01

The ability to manipulate the size and depth of poling inhibited domains, which are produced by UV laser irradiation of the +z face of lithium niobate crystals followed by electric field poling, is demonstrated. It is shown that complex domain structures, much wider than the irradiating laser spot, can be obtained by partially overlapping the subsequent UV laser irradiated tracks. The result of this stitching process is one uniform domain without any remaining trace of its constituent components thus increasing dramatically the utility of this method for the fabrication of surface microstructures as well as periodic and aperiodic domain lattices for nonlinear optical and surface acoustic wave applications. Finally, the impact of multi exposure on the domain characteristics is also investigated indicating that some control over the domain depth can be attained.

Pole orientation of 16 Psyche by two independent methods

NASA Technical Reports Server (NTRS)

Tedesco, E. F.; Taylor, R. C.

1985-01-01

Nineteen new lightcurves of 16 Psyche are presented along with a pole orientation derived using two independent methods, namely, photometric astrometry and magnitude-amplitude-shape-aspect. The pole orientations found using these two methods agree to within 4 deg. The results from applying photometric astrometry were prograde rotation, a sidereal period of 0.1748143 days + or - 0.0000003 days, and a pole at longitude 223 deg and latitude +37 deg, with an uncertainty of 10 deg, and, from applying magnitude-amplitude-shape-aspect a pole at 220 + or - 1 deg, +40 + or - 4 deg, and a modeled triaxial ellipsoid shape (a greater than b greater than c) and a/b = 1.33 + or - 0.07. The discrepancy between the high-pole latitude found here and the low latitudes reported by Lupishko et al. (1982) and Zhou and Yang (1982) is discussed.

The self-consistent dynamic pole tide in global oceans

NASA Technical Reports Server (NTRS)

Dickman, S. R.

1985-01-01

The dynamic pole tide is characterized in a self-consistent manner by means of introducing a single nondifferential matrix equation compatible with the Liouville equation, modelling the ocean as global and of uniform depth. The deviations of the theory from the realistic ocean, associated with the nonglobality of the latter, are also given consideration, with an inference that in realistic oceans long-period modes of resonances would be increasingly likely to exist. The analysis of the nature of the pole tide and its effects on the Chandler wobble indicate that departures of the pole tide from the equilibrium may indeed be minimal.

The Clementine Bistatic Radar Experiment

NASA Technical Reports Server (NTRS)

Nozette, S.; Lichtenberg, C. L.; Spudis, P.; Bonner, R.; Ort, W.; Malaret, E.; Robinson, M.; Shoemaker, E. M.

1996-01-01

During the Clementine 1 mission, a bistatic radar experiment measured the magnitude and polarization of the radar echo versus bistatic angle, beta, for selected lunar areas. Observations of the lunar south pole yield a same-sense polarization enhancement around beta = 0. Analysis shows that the observed enhancement is localized to the permanently shadowed regions of the lunar south pole. Radar observations of periodically solar-illuminated lunar surfaces, including the north pole, yielded no such enhancement. A probable explanation for these differences is the presence of low-loss volume scatterers, such as water ice, in the permanently shadowed region at the south pole.

Quasi-normal modes of holographic system with Weyl correction and momentum dissipation

NASA Astrophysics Data System (ADS)

Wu, Jian-Pin; Liu, Peng

2018-05-01

We study the charge response in complex frequency plane and the quasi-normal modes (QNMs) of the boundary quantum field theory with momentum dissipation dual to a probe generalized Maxwell system with Weyl correction. When the strength of the momentum dissipation α ˆ is small, the pole structure of the conductivity is similar to the case without the momentum dissipation. The qualitative correspondence between the poles of the real part of the conductivity of the original theory and the ones of its electromagnetic (EM) dual theory approximately holds when γ → - γ with γ being the Weyl coupling parameter. While the strong momentum dissipation alters the pole structure such that most of the poles locate at the purely imaginary axis. At this moment, the correspondence between the poles of the original theory and its EM dual one is violated when γ → - γ. In addition, for the dominant pole, the EM duality almost holds when γ → - γ for all α ˆ except for a small region of α ˆ .

Multiwatt-level continuous-wave midwave infrared generation using difference frequency mixing in periodically poled MgO-doped lithium niobate.

PubMed

Guha, Shekhar; Barnes, Jacob O; Gonzalez, Leonel P

2014-09-01

Over 3.5 W of continuous-wave power at 3.4 μm was obtained by single-pass difference frequency mixing of 1.064 and 1.55 μm fiber lasers in a 5 cm long periodically poled lithium niobate crystal. Good agreement was obtained between the observed temperature dependence of the generated power and the prediction from focused Gaussian beam theory.

Electro-optic control of a PPLN-unpoled LiNbO3 boundary for low-voltage Q switching of an intracavity frequency-doubled Nd3+:YVO4 laser.

PubMed

Torregrosa, A J; Maestre, H; Fernández-Pousa, C R; Pereda, J A; Capmany, J

2009-08-01

We present a simple technique to integrate an electro-optic Q switch in a periodically poled bulk lithium niobate crystal bounded by two unpoled (monodomain) regions. The technique exploits the high sensitivity to low applied electric fields of the total internal reflection condition in the periodic poled-unpoled boundary for the small grazing incidence angles associated with the diffraction of a focused Gaussian beam that propagates in the periodically poled region with its axis parallel to the boundary. When the arrangement is placed intracavity to a 1064 nm diode-pumped Nd(3+):YVO(4) laser, it performs simultaneously as a Q switch and as a second-harmonic generator, with Q switching starting at applied voltages as low as 1 V over a 500 microm thickness and with no additional optical elements.

Efficient nonlinear optical conversion of 1.319-micron laser radiation

NASA Astrophysics Data System (ADS)

Byer, Robert L.; Eckardt, Robert C.

1993-01-01

The accomplishments of this program are in the development and application of periodically poled nonlinear optical materials for nonlinear frequency-conversion. We have demonstrated the use of periodically poled lithium niobate (PPLN) as a bulk material for external resonant cavity second-harmonic generation with continuous-wave (cw) output power of 1.7 W. Work that is following this investigation is showing that planar waveguides of PPLN may well be the most satisfactory method of generation of 10's of mW of the 659-nm harmonic of the 1.32-micrometer Nd:YAG laser. We encountered major obstacles obtaining multilayer dielectric coatings necessary to pursue our proposed design of monolithic bulk optical harmonic generators. Additional alternative approaches such as discrete component resonant second harmonic generation employing single domain and periodically poled bulk crystals and monolithic single domain resonators formed by total internal reflection remain under investigation.

Circular polarimetry of EXO 033319-2554.2 - A new eclipsing AM Herculis star

NASA Technical Reports Server (NTRS)

Berriman, Graham; Smith, Paul S.

1988-01-01

This Letter presents circular polarimetry that unequivocally identifies EXO 033319-2554.2 as only the third eclipsing AM Her star and brings the total number of AM Her stars now identified to 14. The orbital period is 126.4 minutes, as previously reported, and defines a new short-period edge to the period gap seen in all classes of cataclysmic variable stars. EXO 033319-2554.2 shows 2.5 mag deep eclipses of the predominantly accreting magnetic pole on the white dwarf. Before the eclipse, the pole rotates into the line of sight and shows white-light circular polarization, due to cyclotron radiation, that reaches values as high as 10 percent. There is some evidence that the second pole is emitting cyclotron radiation too. How high time resolution photometry, linear polarimetry, and spectroscopy will be of great value in understanding this system.

Medial prefrontal aberrations in major depressive disorder revealed by cytoarchitectonically informed voxel-based morphometry

PubMed Central

Bludau, Sebastian; Bzdok, Danilo; Gruber, Oliver; Kohn, Nils; Riedl, Valentin; Sorg, Christian; Palomero-Gallagher, Nicola; Müller, Veronika I.; Hoffstaedter, Felix; Amunts, Katrin; Eickhoff, Simon B.

2017-01-01

Objective The heterogeneous human frontal pole has been identified as a node in the dysfunctional network of major depressive disorder. The contribution of the medial (socio-affective) versus lateral (cognitive) frontal pole to major depression pathogenesis is currently unclear. The present study performs morphometric comparison of the microstructurally informed subdivisions of human frontal pole between depressed patients and controls using both uni- and multivariate statistics. Methods Multi-site voxel- and region-based morphometric MRI analysis of 73 depressed patients and 73 matched controls without psychiatric history. Frontal pole volume was first compared between depressed patients and controls by subdivision-wise classical morphometric analysis. In a second approach, frontal pole volume was compared by subdivision-naive multivariate searchlight analysis based on support vector machines. Results Subdivision-wise morphometric analysis found a significantly smaller medial frontal pole in depressed patients with a negative correlation of disease severity and duration. Histologically uninformed multivariate voxel-wise statistics provided converging evidence for structural aberrations specific to the microstructurally defined medial area of the frontal pole in depressed patients. Conclusions Across disparate methods, we demonstrated subregion specificity in the left medial frontal pole volume in depressed patients. Indeed, the frontal pole was shown to structurally and functionally connect to other key regions in major depression pathology like the anterior cingulate cortex and the amygdala via the uncinate fasciculus. Present and previous findings consolidate the left medial portion of the frontal pole as particularly altered in major depression. PMID:26621569

Load Testing, Finite Element Analysis, and Design of Steel Traffic-Signal Poles

DOT National Transportation Integrated Search

1993-07-01

At request of the Structures Design and Construction Division, the Engineering Research and Development Bureau performed full-scale testing and finite element analysis (FEA) of span-wire traffic-signal poles to evaluate their structural adequacy. Res...

Note on de Haas-van Alphen diamagnetism in thin, free-electron films

NASA Astrophysics Data System (ADS)

Grzesik, J. A.

2012-03-01

We revisit the problem of de Haas-van Alphen (dHvA) diamagnetic susceptibility oscillations in a thin, free-electron film trapped in a synthetic harmonic potential well. A treatment of this phenomenon at zero temperature was announced many years ago by Childers and Pincus (designated hereafter as CP), and we traverse initially much the same ground, but from a slightly different analytic perspective. That difference hinges around our use, in calculating the Helmholtz free energy F, of an inverse Laplace transform, Bromwich-type contour integral representation for the sharp distribution cutoff at Fermi level μ. The contour integral permits closed-form summation all at once over the discrete orbital Landau energy levels transverse to the magnetic field, and the energy associated with the in-plane canonical momenta ℏ k x and ℏ k z. Following such summation/integration, pole/residue pairs appear in the plane of complex transform variable s, a fourth-order pole at origin s = 0, and an infinite ladder, both up and down, of simple poles along the imaginary axis. The residue sum from the infinite pole ladder automatically engenders a Fourier series with period one in dimensionless variable μ/ ℏ ω (with effective angular frequency ω suitably defined), series which admits closed-form summation as a cubic polynomial within any given periodicity slot. Such periodicity corresponds to Landau levels slipping sequentially beneath Fermi level μ as the ambient magnetic field H declines in strength, and is manifested by the dHvA pulsations in diamagnetic susceptibility. The coëxisting steady contribution from the pole at origin has a similar cubic structure but is opposite in sign, inducing a competition whose outcome is a net magnetization that is merely quadratic in any given periodicity slot, modulated by a slow amplitude growth. Apart from some minor notes of passing discord, these simple algebraic structures confirm most of the CP formulae, and their graphic display reveals a numerically faithful portrait of the oscillatory dHvA diamagnetic susceptibility phenomenon. The calculations on view have a merely proof-of-principle aim, with no pretense at all of being exhaustive. The zero-temperature results hold moreover the key to the entire panorama of finite-temperature thermodynamics with T > 0. Indeed, thanks to the elegant work of Sondheimer and Wilson, one can promote the classical, Maxwell-Boltzmann partition function Z ( s ), via an inverse Laplace transform of its ratio to s 2, directly into the required, Fermi-Dirac Helmholtz free energy F at finite temperature T > 0. While the underlying cubic polynomial commonality continues to bestow decisive algebraic advantages, the evolving formulae are naturally more turgid than their zero-temperature counterparts. Nevertheless we do retain control over them by exhibiting their retrenchment into precisely these antecedents. So fortified, we undertake what is at once both a drastic and yet a simple-minded step of successive approximation, a step which clears the path toward numerical evaluation of the finite-temperature diamagnetic susceptibility. We are rewarded finally with a persistent dHvA periodicity imprint, but with its peaks increasingly flattened and its valleys filled in response to temperature rise, all as one would expect on physical grounds.

Is flexible ureterorenoscopy and laser lithotripsy the new gold standard for lower pole renal stones when compared to shock wave lithotripsy: Comparative outcomes from a University hospital over similar time period

PubMed Central

Burr, Jacob; Ishii, Hiro; Simmonds, Nick

2015-01-01

Introduction Renal lower pole stones pose difficulty in management due to anatomical variation, stone size, hardness and patient demographics. Flexible ureterorenoscopy and laser lithotripsy (FURSL) and shock wave lithotripsy (SWL) are preferred for stones 1-2 cm in size. We wanted to compare the outcomes of FURSL and SWL for lower pole stones during the same time period. Material and methods All patients who were treated for lower pole stones with FURSL and SWL during a 19-month period were included. The stone free rate (SFR) was defined as ≤3 mm fragments on follow-up imaging or stone free endoscopically. Data was recorded in an excel spreadsheet with SPSS version 21 used for statistical analysis. Results A total of 161 lower pole procedures were done (93 SWL and 63 FURSL). The mean stone size for SWL (7.4 mm; range: 4-16 mm) was significantly smaller than for FURSL (13.4 mm; 4-53 mm). The mean operating time and hospital stay for FURSL was 65 minutes (range: 30-160 minutes) and 0.5 days (range: 0-7 days) respectively. The SFR was significantly better (p <0.001) for FURSL (n = 63, 93%) compared to SWL (n = 23, 25%). There were 4 (6%) complications (3 Clavien II and 1 Clavien I) in the FURSL group (2 urosepsis, 1 UTI and 1 stent pain). Three patients in the SWL group (Clavien I) were readmitted with renal colic but there were no other complications. Conclusions FURSL for lower pole stones seems to be a much better alternative than SWL with a high SFR even for larger stones and seems to be the new gold standard for lower pole stone management. PMID:26251738

Study of the effects of wind power and vortex-induced vibrations to establish fatigue design criteria for high-mast poles.

DOT National Transportation Integrated Search

2011-08-01

Traffic signal and high-mast poles are used by transportation agencies to control and illuminate intersections; their structural design is governed by national specifications. High-mast poles are luminaire supports located near highway interchanges t...

High-mast light poles anchor nut loosening in Alaska : an investigation of field monitoring and finite-element analysis.

DOT National Transportation Integrated Search

2014-09-01

High mast lighting poles (HMLPs) are tall, roadside structures effective for lighting large areas of highways and intersections. The Alaska Department of Transportation : and Public Facilities (AKDOT&PF) maintains 118 such poles in the greater Anchor...

Poling of Microwave Electro-Optic Devices

NASA Technical Reports Server (NTRS)

Singer, Kenneth D.

1997-01-01

The desire to transmit high frequency, microwave RF signals over fiber optic cables has necessitated the need for electro-optic modulation devices. However, in order to reap these potential benefits, it is necessary to develop the devices and their associated fabrication processes, particularly those processes associated with the poling of the devices. To this end, we entered into a cooperative research agreement with Richard Kunath of NASA LeRC. A graduate student in my group, Tony Kowalczyk, worked closely with the group at NASA to develop processes for construction of a microwave frequency electro-optic modulator. Materials were commercially obtained from Amoco Chemical and in collaboration with Lockheed-Martin. The photolithography processes were developed at NASA LeRC and the electric-field poling process was carried out in our laboratory at CWRU. During the grant period, the poling process conditions were investigated for these multilayer devices. Samples were poled and the resulting nonlinear optical properties were evaluated in our laboratory. Following the grant period, Kowalczyk went to NASA under a NRC fellowship, and I continued to collaborate as a consultant. Publications listed at the end of this report came out of this work. Another manuscript is in preparation and will be submitted shortly.

Simplified Model to Predict Deflection and Natural Frequency of Steel Pole Structures

NASA Astrophysics Data System (ADS)

Balagopal, R.; Prasad Rao, N.; Rokade, R. P.

2018-04-01

Steel pole structures are suitable alternate to transmission line towers, due to difficulty encountered in finding land for the new right of way for installation of new lattice towers. The steel poles have tapered cross section and they are generally used for communication, power transmission and lighting purposes. Determination of deflection of steel pole is important to decide its functionality requirement. The excessive deflection of pole may affect the signal attenuation and short circuiting problems in communication/transmission poles. In this paper, a simplified method is proposed to determine both primary and secondary deflection based on dummy unit load/moment method. The predicted deflection from proposed method is validated with full scale experimental investigation conducted on 8 m and 30 m high lighting mast, 132 and 400 kV transmission pole and found to be in close agreement with each other. Determination of natural frequency is an important criterion to examine its dynamic sensitivity. A simplified semi-empirical method using the static deflection from the proposed method is formulated to determine its natural frequency. The natural frequency predicted from proposed method is validated with FE analysis results. Further the predicted results are validated with experimental results available in literature.

Research on key factors and their interaction effects of electromagnetic force of high-speed solenoid valve.

PubMed

Liu, Peng; Fan, Liyun; Hayat, Qaisar; Xu, De; Ma, Xiuzhen; Song, Enzhe

2014-01-01

Analysis consisting of numerical simulations along with lab experiments of interaction effects between key parameters on the electromagnetic force based on response surface methodology (RSM) has been also proposed to optimize the design of high-speed solenoid valve (HSV) and improve its performance. Numerical simulation model of HSV has been developed in Ansoft Maxwell environment and its accuracy has been validated through lab experiments. Effect of change of core structure, coil structure, armature structure, working air gap, and drive current on the electromagnetic force of HSV has been analyzed through simulation model and influence rules of various parameters on the electromagnetic force have been established. The response surface model of the electromagnetic force has been utilized to analyze the interaction effect between major parameters. It has been concluded that six interaction factors including working air gap with armature radius, drive current with armature thickness, coil turns with side pole radius, armature thickness with its radius, armature thickness with side pole radius, and armature radius with side pole radius have significant influence on the electromagnetic force. Optimal match values between coil turns and side pole radius; armature thickness and side pole radius; and armature radius and side pole radius have also been determined.

Research on Key Factors and Their Interaction Effects of Electromagnetic Force of High-Speed Solenoid Valve

PubMed Central

Fan, Liyun; Xu, De; Ma, Xiuzhen; Song, Enzhe

2014-01-01

Analysis consisting of numerical simulations along with lab experiments of interaction effects between key parameters on the electromagnetic force based on response surface methodology (RSM) has been also proposed to optimize the design of high-speed solenoid valve (HSV) and improve its performance. Numerical simulation model of HSV has been developed in Ansoft Maxwell environment and its accuracy has been validated through lab experiments. Effect of change of core structure, coil structure, armature structure, working air gap, and drive current on the electromagnetic force of HSV has been analyzed through simulation model and influence rules of various parameters on the electromagnetic force have been established. The response surface model of the electromagnetic force has been utilized to analyze the interaction effect between major parameters. It has been concluded that six interaction factors including working air gap with armature radius, drive current with armature thickness, coil turns with side pole radius, armature thickness with its radius, armature thickness with side pole radius, and armature radius with side pole radius have significant influence on the electromagnetic force. Optimal match values between coil turns and side pole radius; armature thickness and side pole radius; and armature radius and side pole radius have also been determined. PMID:25243217

Ulysses discovers the mysteries of the sun's south pole

NASA Astrophysics Data System (ADS)

1994-09-01

Scientists at ESA's space research and technology centre in Noordwijk (the Netherlands) this morning gave a very positive account of the South polar pass phase, which started in June and will be completed in November. In particular they concluded that the south polar region displayed unexpected magnetic and dynamic characteristics; this probably means that the thinking on the magnetic structure of the Sun will have to be revised. The first thing that surprised the scientists was the low cosmic radiation activity above the south pole and the remarkable apparent absence of a south magnetic pole. Richard Marsden, ESA's project scientist, explained: "We expected the Sun to have a relatively simple magnetic field, such as the Earth's or that of a magnetised iron bar. We thought we were going to find a local increase in the field's intensity. But the probe did not detect any such thing and all the evidence so far suggests that the Sun has no south magnetic pole. Could it be that the Sun has no south magnetic pole? Or is one suddenly going to appear before Ulysses completes its pass? These are some of the questions exercising the minds of the team of scientists working on the project, who are keenly looking forward to comparing these results with those that will be coming through next year when the probe passes over the Sun's north geographic pole. It is however already manifestly clear that the structure of the solar magnetic field in the southern polar region is not as predicted by the models. In particular, the instruments on board Ulysses have detected a new type of very slowly varying electromagnetic waves, with oscillation periods of 10 to 20 hours. The experts' theory is that this is due to an unexpected phenomenon that conveys the solar magnetic field into space through the solar wind. It is still far too early to say what effect these new findings are going to have on our overall understanding of the Sun and the interplanetary wind it generates. A vast volume of data running into billions of bits, all of it of great scientific value, has been acquired during the first part of this polar pass. Detailed analysis is going to take many months. However, one thing about which there is no doubt is the complexity of the phenomena observed, which involve the combined effects of the solar wind, magnetic field, electromagnetic waves and fast-moving bursts of particles. Further insights will probably be gained when Ulysses passes over the Sun's north pole in 1995 and, if the mission is extended, when it makes two further polar passes in 2000-2001, during a period of intense magnetic activity. (*) Ulysses is a joint ESA/NASA mission. ESA developed the probe and is contributing an estimated ECU 170 million up to 1995 to its in-fl operation. European research laboratories provided half of the scie instruments. NASA provided the other half of the experiments flown a radio-isotopic power generator and the launch; it is also maintain day-to-day communications with the probe via its dedicated antennas.

Structure of hadron resonances with a nearby zero of the amplitude

NASA Astrophysics Data System (ADS)

Kamiya, Yuki; Hyodo, Tetsuo

2018-03-01

We discuss the relation between the analytic structure of the scattering amplitude and the origin of an eigenstate represented by a pole of the amplitude. If the eigenstate is not dynamically generated by the interaction in the channel of interest, the residue of the pole vanishes in the zero coupling limit. Based on the topological nature of the phase of the scattering amplitude, we show that the pole must encounter with the Castillejo-Dalitz-Dyson (CDD) zero in this limit. It is concluded that the dynamical component of the eigenstate is small if a CDD zero exists near the eigenstate pole. We show that the line shape of the resonance is distorted from the Breit-Wigner form as an observable consequence of the nearby CDD zero. Finally, studying the positions of poles and CDD zeros of the K ¯ N -π Σ amplitude, we discuss the origin of the eigenstates in the Λ (1405 ) region.

Structuring of material parameters in lithium niobate crystals with low-mass, high-energy ion radiation

NASA Astrophysics Data System (ADS)

Peithmann, K.; Eversheim, P.-D.; Goetze, J.; Haaks, M.; Hattermann, H.; Haubrich, S.; Hinterberger, F.; Jentjens, L.; Mader, W.; Raeth, N. L.; Schmid, H.; Zamani-Meymian, M.-R.; Maier, K.

2011-10-01

Ferroelectric lithium niobate crystals offer a great potential for applications in modern optics. To provide powerful optical components, tailoring of key material parameters, especially of the refractive index n and the ferroelectric domain landscape, is required. Irradiation of lithium niobate crystals with accelerated ions causes strong structured modifications in the material. The effects induced by low-mass, high-energy ions (such as 3He with 41 MeV, which are not implanted, but transmit through the entire crystal volume) are reviewed. Irradiation yields large changes of the refractive index Δn, improved domain engineering capability within the material along the ion track, and waveguiding structures. The periodic modification of Δn as well as the formation of periodically poled lithium niobate (PPLN) (supported by radiation damage) is described. Two-step knock-on displacement processes, 3He→Nb and 3He→O causing thermal spikes, are identified as origin for the material modifications.

Two-axis tracker for solar panels and the like

DOEpatents

Liao, Henry H.

2013-04-16

A tracker including an outer post having elongated bore and a lower end mounted on a sub-structure, an inner pole rotatably received in the elongated bore, a lower bearing in the bore adjacent a lower end of the outer post and attached thereto to be constrained from lateral movement and mounted on the sub-structure such that a lower end of the inner pole rests on and is supported by the lower bearing, an upper bearing near an upper end of the outer post, a circumferential drive supported on the outer post for rotating the inner pole relative to the outer post, such that substantially a full weight of a load on the inner pole is directly transmitted to the sub-structure and lateral force and torque leverage are placed on a full length of the outer post by way of the upper and lower bearing.

Unraveling the nature of electric field- and stress- induced structural transformations in soft PZT by a new powder poling technique.

PubMed

Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev

2015-02-25

A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization.

Calligraphic Poling for WGM Resonators

NASA Technical Reports Server (NTRS)

Mohageg, Makan; Strekalov, Dmitry; Savchenkov, Anatoliy; Matsko, Andrey; Ilchenko, Vladimir; Maleki, Lute

2007-01-01

By engineering the geometry of a nonlinear optical crystal, the effective efficiency of all nonlinear optical oscillations can be increased dramatically. Specifically, sphere and disk shaped crystal resonators have been used to demonstrate nonlinear optical oscillations at sub-milliwatt input power when cs light propagates in a Whispering Gallery Mode (WGM) of such a resonant cavity. in terms of both device production and experimentation in quantum optics, some nonlinear optical effects with naturally high efficiency can occult the desired nonlinear scattering process. the structure to the crystal resonator. In this paper, I will discuss a new method for generating poling structures in ferroelectric crystal resonators called calligraphic poling. The details of the poling apparatus, experimental results and speculation on future applications will be discussed.

All-periodically poled, high-power, continuous-wave, single-frequency tunable UV source.

PubMed

Aadhi, A; Chaitanya N, Apurv; Jabir, M V; Singh, R P; Samanta, G K

2015-01-01

We report on experimental demonstration of an all-periodically poled, continuous-wave (CW), high-power, single-frequency, ultra-violet (UV) source. Based on internal second-harmonic-generation (SHG) of a CW singly resonant optical parametric oscillator (OPO) pumped in the green, the UV source provides tunable radiation across 398.94-417.08 nm. The compact source comprising of a 25-mm-long MgO-doped periodically poled stoichiometric lithium tantalate (MgO:sPPLT) crystal of period Λ(SLT)=8.5  μm for OPO and a 5-mm-long, multi-grating (Λ(KTP)=3.3, 3.4, 3.6 and 3.8 μm), periodically poled potassium titanium phosphate (PPKTP) for intra-cavity SHG, provides as much as 336 mW of UV power at 398.94 nm, corresponding to a green-to-UV conversion efficiency of ∼6.7%. In addition, the singly resonant OPO (SRO) provides 840 mW of idler at 1541.61 nm and substantial signal power of 108 mW at 812.33 nm transmitted through the high reflective cavity mirrors. UV source provides single-frequency radiation with instantaneous line-width of ∼18.3  MHz and power >100  mW in Gaussian beam profile (ellipticity >92%) across the entire tuning range. Access to lower UV wavelengths requires smaller grating periods to compensate high phase-mismatch resulting from high material dispersion in the UV wavelength range. Additionally, we have measured the normalized temperature and spectral acceptance bandwidth of PPKTP crystal in the UV wavelength range to be ∼2.25°C·cm and ∼0.15  nm·cm, respectively.

Tailoring single-cycle electromagnetic pulses in the 2-9 THz frequency range using DAST/SiO₂ multilayer structures pumped at Ti:sapphire wavelength.

PubMed

Stepanov, Andrei G; Rogov, Andrii; Bonacina, Luigi; Wolf, Jean-Pierre; Hauri, Christoph P

2014-09-08

We present a numerical parametric study of single-cycle electromagnetic pulse generation in a DAST/SiO₂multilayer structure via collinear optical rectification of 800 nm femtosecond laser pulses. It is shown that modifications of the thicknesses of the DAST and SiO₂layers allow tuning of the average frequency of the generated THz pulses in the frequency range from 3 to 6 THz. The laser-to-THz energy conversion efficiency in the proposed structures is compared with that in a bulk DAST crystal and a quasi-phase-matching periodically poled DAST crystal and shows significant enhancement.

Longitude origins on moving equator II: effects of nutation

NASA Astrophysics Data System (ADS)

Fukushima, T.

We obtained an explicit solution of s, the angle specifying the non-rotating orign (NRO) (Guinot 1979), for the pole uniformly rotating on a circle around an arbitrary fixed direction. Thanks to the obtained formula, we derived an approximate expression of its correction, Δs, due to the fast nutational motion of the pole by ignoring the slow precessional motion. By adopting the IAU 1980 nutation series (Seidelmann 1980) and combining the result with the previous solution for the precessional motion of the Earth's pole (Fukushima 2000), we developed a more precise expression of the global motion of the Celestial Ephemeris Origin (CEO). The current speed of global rotation of CEO amounts to -4.149 688 1"/yr where the contribution of the nutation is small as -38.4μas/yr but non-negligible. The negative sign shows that CEO rotates clockwise with respect to the inertial frame when viewed from the north pole. The long periodic motion of CEO is of the amplitude of the obliquity of ecliptic, around 23.5 degree, and of the period of precession, around 25800 yr. While the effect of nutation on the periodic motion of CEO looks like a series of mixed secular terms, which is simply proportional to the nutation in longitude and is of the order of some tens mas/yr.

A Conventional Mean Pole

NASA Astrophysics Data System (ADS)

Stamatakos, N. G.; McCarthy, D. D.

2016-12-01

A CONVENTIONAL MEAN POLE PATH The gradual drift of the pole associated with the rotational axis of the Earth in a terrestrial reference frame is characterized by the motion of a "mean pole." The IERS Conventions (2010) does not provide a formal definition of such a "mean pole." In its glossary it defines the terminology "mean pole" in the celestial frame by using the definition "the position on the celestial sphere towards which the Earth's axis points at a particular epoch, with the oscillations due to precession-nutation removed." The need for a terrestrial mean pole is mentioned in Section 7.1.4 of the IERS Conventions, which outlines the procedure to account for the variation in terrestrial site coordinates caused by the pole tide. It states, that an estimate of the wander of the mean pole to within about 10 milliarc-seconds is needed to ensure that the geopotential field is aligned to the long term mean pole. Historically the angular coordinates of this "mean pole" were calculated by averaging the observed angular coordinates of the rotational pole over six years, the beat period of the annual and approximately 14-month Chandler motions of the rotational pole. The IERS Conventions (2010) realization of the mean pole is composed of a cubic fit of the polar coordinates valid over 1976-2010 and a linear model for extrapolation after 2010.0. Further it notes that in the future, the IERS conventional mean pole will be revised as needed with sufficient advance notice. However, this document leaves open the formal definition of a conventional terrestrial mean pole, the spectral frequency content to be expected in such a definition and a procedure to be used to realize the coordinates of the path for users. Background is provided regarding past realizations of a "mean pole," and the requirements for a realization of a mean pole path are reviewed. Possible definitions and potential mathematical models to provide mean pole coordinates in the future are outlined. In addition, the authors hope that this poster will serve to open a discussion, which will identify geodesy disciplines that require a mean pole and what type of definition would be suitable to their needs.

Cavity-enhanced generation of 6 W cw second-harmonic power at 532 nm in periodically-poled MgO:LiTaO3.

PubMed

Ricciardi, Iolanda; De Rosa, Maurizio; Rocco, Alessandra; Ferraro, Pietro; De Natale, Paolo

2010-05-24

We report on efficient cw high-power second harmonic generation in a periodically poled LiTaO3 crystal placed in a resonant enhancement cavity. We tested three configurations, differing in the coupling mirror reflectivity, and a maximum conversion efficiency of about 76%, corresponding to 6.1 W of green light with 8.0 W of fundamental power, was achieved. This is, to the best of our knowledge, the highest cw power ever reported using a periodically-poled crystal in an external cavity. We observed photo-thermal effect induced by photon absorption at the mirrors and in the crystal, which however does not affect stable operation of the cavity. A further effect arises for two out of the three configurations, at higher values of the input power, which degrades the performance of the locked cavity. We suggest this effect is due to the onset of competing nonlinearities in the same crystal.

Acoustic wave filter based on periodically poled lithium niobate.

PubMed

Courjon, Emilie; Bassignot, Florent; Ulliac, Gwenn; Benchabane, Sarah; Ballandras, Sylvain

2012-09-01

Solutions for the development of compact RF passive transducers as an alternative to standard surface or bulk acoustic wave devices are receiving increasing interest. This article presents results on the development of an acoustic band-pass filter based on periodically poled ferroelectric domains in lithium niobate. The fabrication of periodically poled transducers (PPTs) operating in the range of 20 to 650 MHz has been achieved on 3-in (76.2-mm) 500-μm-thick wafers. This kind of transducer is able to excite elliptical as well as longitudinal modes, yielding phase velocities of about 3800 and 6500 ms(-1), respectively. A new type of acoustic band-pass filter is proposed, based on the use of PPTs instead of the SAWs excited by classical interdigital transducers. The design and the fabrication of such a filter are presented, as well as experimental measurements of its electrical response and transfer function. The feasibility of such a PPT-based filter is thereby demonstrated and the limitations of this method are discussed.

Periodically poled lithium niobate by electron beam: irradiation conditions and second harmonic generation

NASA Astrophysics Data System (ADS)

Restoin, C.; Couderc, Vincent; Darraud-Taupiac, Claire; Decossas, J.-Louis; Vareille, J.-C.; Barthelemy, Alain; Hauden, Jerome

2000-12-01

Second Harmonic Generation (SHG) using counter-propagating Quasi Phase Matching (QPM) configuration often requires a fine non-linearity with a period of a fraction of a micrometer. The direct Electron Beam (EB) domain reversal technique seems to be promising to achieve gratings on LiNbO3 with such a small period compared to other current poling technologies as it is lithographic free and exhibits a very high theoretical resolution (5 mm). We present here, a preliminary study concerning the influence of EB irradiation conditions on domain inversion; SHG is also examined on a 6.58 j.tm inverted periodic domain grating in lithium niobate using a Nd-YaG laser light. It is well known that LiNbO3 is an attractive material for many optical applications because of its transparency over a large wavelength band (350 mm to 5000 mm) and its high nonlinear coefficients. EB irradiation is performed using a Scanning Electron Microscope (SEM) driven by a Computer Aided Design (CAD) application developed in our laboratory. Various structures such as periodic gratings can be written with the chosen period. The ferroelectric domain inversion is investigated as a function of the accelerating voltage of the electrons (10 to 30 kV), the scanning speed of the EB (0.97 to 7.76 mm/s) and the current received by the sample (1.6 to 14 nA). The inversion patterns have been revealed by chemical etching (HF) and they have been observed using SEM. It has been shown that the duty cycle is respected on the irradiated face. The SHG conversion efficiency is measured as a function of the temperature and the grating period is calculated (value of6.564 jim).

Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization

DOEpatents

Doughty, Frank C.; Spencer, John E.

2000-12-19

In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

30 CFR 75.705-1 - Work on high-voltage lines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... power system, either the steel armor or conduit enclosing the system or a surface grounding field is a... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

30 CFR 75.705-1 - Work on high-voltage lines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... power system, either the steel armor or conduit enclosing the system or a surface grounding field is a... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

30 CFR 75.705-1 - Work on high-voltage lines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... power system, either the steel armor or conduit enclosing the system or a surface grounding field is a... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

30 CFR 77.704-1 - Work on high-voltage lines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ungrounded power system, either the steel armor or conduit enclosing the system or a surface grounding field... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

30 CFR 77.704-1 - Work on high-voltage lines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ungrounded power system, either the steel armor or conduit enclosing the system or a surface grounding field... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

30 CFR 77.704-1 - Work on high-voltage lines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ungrounded power system, either the steel armor or conduit enclosing the system or a surface grounding field... supported by any pole or structure which also supports other high-voltage lines until: (1) All lines supported on the pole or structure are deenergized and grounded in accordance with all of the provisions of...

Development of smart wave mitigation structure using array of poles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Asanuma, Hiroshi

2017-05-01

This paper describes reduction of water flow velocity by array of poles as a new wave mitigation structure. This structure is based on tsunami mitigation coastal forest. As natural forests have many problems such as low fraction of trees, low visibility of ocean waves, low strength, long of time to grow, and so on. To cope with these problems, a new wave mitigation structure has been developed, which are intended to add better capability of high wave or tsunami mitigation effect to actual ones by optimizing various parameters such as configuration, distribution density and material properties. In this study, the effect of type of material and its combination were mainly investigated. According to the results, reduction rate of the flow velocity increases with increasing number of rows for each material up to a certain level, and that of poles having lower Young's modulus is generally higher than that of those having higher Young's modulus. The effect of combination of materials was also investigated and drastic increase of mitigation effect was found when soft and hard poles were combined.

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

Helled, R., E-mail: rhelled@ucla.edu

Knowledge of Saturn's axial moment of inertia can provide valuable information on its internal structure. We suggest that Saturn's angular momentum may be determined by the Solstice Mission (Cassini XXM) by measuring Saturn's pole precession rate and the Lense-Thirring acceleration on the spacecraft, and therefore put constraints on Saturn's moment of inertia. It is shown that Saturn's moment of inertia can change up to {approx}2% due to different core properties. However, a determination of Saturn's rotation rate is required to constrain its axial moment of inertia. A change of about seven minutes in rotation period leads to a similar uncertaintymore » in the moment of inertia value as different core properties (mass, radius). A determination of Saturn's angular momentum and rotation period by the Solstice Mission could reveal important information on Saturn's internal structure, in particular, its core properties.« less

Influence of annealing on the photodeposition of silver on periodically poled lithium niobate

DOE PAGES

Carville, N. Craig; Neumayer, Sabine M.; Manzo, Michele; ...

2016-02-03

Here, the preferential deposition of metal nanoparticles onto periodically poled lithium niobate surfaces, whereby photogenerated electrons accumulate in accordance with local electric fields and reduce metal ions from solution, is known to depend on the intensity and wavelength of the illumination and the concentration of the solution used. Here, it is shown that for identical deposition conditions (wavelength, intensity, concentration), post-poling annealing for 10 h at 200 °C modifies the surface reactivity through the reorientation of internal defect fields. Whereas silver nanoparticles deposit preferentially on the +z domains on unannealed crystals, the deposition occurs preferentially along 180 degrees domain wallsmore » for annealed crystals. In neither case is the deposition selective; limited deposition occurs also on the unannealed -z domain surface and on both annealed domain surfaces. The observed behavior is attributed to a relaxation of the poling-induced defect frustration mediated by Li + ion mobility during annealing, which affects the accumulation of electrons, thereby changing the surface reactivity. The evolution of the defect field with temperature is corroborated using Raman spectroscopy.« less

Effect of roof strength in injury mitigation during pole impact.

PubMed

Friedman, Keith; Hutchinson, John; Mihora, Dennis; Kumar, Sri; Frieder, Russell; Sances, Anthony

2007-01-01

Motor vehicle accidents involving pole impacts often result in serious head and neck injuries to occupants. Pole impacts are typically associated with rollover and side collisions. During such events, the roof structure is often deformed into the occupant survival space. The existence of a strengthened roof structure would reduce roof deformation and accordingly provide better protection to occupants. The present study examines the effect of reinforced (strengthened) roofs using experimental crash study and computer model simulation. The experimental study includes the production cab structure of a pickup truck. The cab structure was loaded using an actual telephone pole under controlled laboratory conditions. The cab structure was subjected to two separate load conditions at the A-pillar and door frame. The contact force and deformation were measured using a force gauge and potentiometer, respectively. A computer finite element model was created to simulate the experimental studies. The results of finite element model matched well with experimental data during two different load conditions. The validated finite element model was then used to simulate a reinforced roof structure. The reinforced roof significantly reduced the structural deformations compared to those observed in the production roof. The peak deformation was reduced by approximately 75% and peak velocity was reduced by approximately 50%. Such a reduction in the deformation of the roof structure helps to maintain a safe occupant survival space.

Fabrication and structural properties of AlN submicron periodic lateral polar structures and waveguides for UV-C applications

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

Alden, D.; Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin; Guo, W.

Periodically poled AlN thin films with submicron domain widths were fabricated for nonlinear applications in the UV-VIS region. A procedure utilizing metalorganic chemical vapor deposition growth of AlN in combination with laser interference lithography was developed for making a nanoscale lateral polarity structure (LPS) with domain size down to 600 nm. The Al-polar and N-polar domains were identified by wet etching the periodic LPS in a potassium hydroxide solution and subsequent scanning electron microscopy (SEM) characterization. Fully coalesced and well-defined vertical interfaces between the adjacent domains were established by cross-sectional SEM. AlN LPSs were mechanically polished and surface roughness with amore » root mean square value of ∼10 nm over a 90 μm × 90 μm area was achieved. 3.8 μm wide and 650 nm thick AlN LPS waveguides were fabricated. The achieved domain sizes, surface roughness, and waveguides are suitable for second harmonic generation in the UVC spectrum.« less

Nonuniformity of the Earth's rotation and the motion of the poles

NASA Technical Reports Server (NTRS)

Sidorenkov, N. S.

1983-01-01

The study of the nonuniformity of the Earth's rotation and the motion of the poles has great practical and theoretical significance. This study makes it possible to determine the coordinates of celestial and terrestrial objects, and to gain information in many domains of earth science. This paper reviews studies of rotation nonuniformity and polar motion, giving attention to astronomical data; the nature of periodic oscillations of the Earth's rotation; the nature of long-period variations of the Earth's rotation rate; and the use of Earth-rotation data in hydrometeorology.

Stimulated Raman scattering in an optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3.

PubMed

My, T-H; Robin, O; Mhibik, O; Drag, C; Bretenaker, F

2009-03-30

The evolution of the spectrum of a singly resonant optical parametric oscillator based on an MgO-doped periodically poled stoichiometric lithium tantalate crystal is observed when the pump power is varied. The onset of cascade Raman lasing due to stimulated Raman scattering in the nonlinear crystal is analyzed. Spurious frequency doubling and sum-frequency generation phenomena are observed and understood. A strong reduction of the intracavity Raman scattering is obtained by a careful adjustment of the cavity losses.

Optical parametric amplification of arbitrarily polarized light in periodically poled LiNbO3.

PubMed

Shao, Guang-hao; Song, Xiao-shi; Xu, Fei; Lu, Yan-qing

2012-08-13

Optical parametric amplification (OPA) of arbitrarily polarized light is proposed in a multi-section periodically poled Lithium Niobate (PPLN). External electric field is applied on selected sections to induce the polarization rotation of involved lights, thus the quasi-phase matched optical parametric processes exhibit polarization insensitivity under suitable voltage. In addition to the amplified signal wave, an idler wave with the same polarization is generated simultaneously. As an example, a ~10 times OPA showing polarization independency is simulated. Applications of this technology are also discussed.

Extended phase matching of second-harmonic generation in periodically poled KTiOPO4 with zero group-velocity mismatch

NASA Astrophysics Data System (ADS)

König, Friedrich; Wong, Franco N. C.

2004-03-01

Under extended phase-matching conditions, the first frequency derivative of the wave-vector mismatch is zero and the phase-matching bandwidth is greatly increased. We present extensive three-wave mixing measurements of the wave-vector mismatch and obtain improved Sellmeier equations for KTiOPO4. We observed a type-II extended phase-matching bandwidth of 100 nm for second-harmonic generation in periodically poled KTiOPO4, centered at the fundamental wavelength of 1584 nm. Applications in quantum entanglement and frequency metrology are discussed.

The efficacy of radiographic anatomical measurement methods in predicting success after extracorporeal shockwave lithotripsy for lower pole kidney stones.

PubMed

Arpali, Emre; Altinel, Mert; Sargin, Semih Yasar

2014-01-01

To assess the impact of lower pole calyceal anatomy on clearace of lower pole stones after extracorporeal shockwave lithotripsy (ESWL) by means of a new and previously defined radiographic measurement method. Sixty-four patients with solitary radiopaque lower pole kidney stones were enrolled in the study. Infundibulopelvic angle (IPA), infundibulotransverse angle (ITA), infundibular lenght(IL), and infundibular width (IW) were measured on the intravenous urographies which were taken before the procedure. 48 of 64 patients (75%) were stone-free after a follow-up period of 3 months. The IPA,ITA,IL and IW were determined as statistically significant factors, while age,gender and stone area were found to have no impact on clearance. By the help of radiographic measurement methods related to lower pole kidney anatomy, appropriate patient selection and increment in success after ESWL may be achieved.

The pole tide in deep oceans

NASA Technical Reports Server (NTRS)

Dickman, S. R.

1990-01-01

The fluid-dynamical theory of the pole tide is examined by describing the oceanic response to the Chandler wobble and assessing its implications for mantle anelasticity and low-frequency ocean dynamics. The Laplace tide equations accounting for bottom friction are given, and a spherical harmonic approach is delineated in which the time-independent portion of the tide height is expanded. Pole-tide height and related inertia products are linearly proportional to wobble amplitude, and the final equations are modified to account for mantle elasticity and oceanic loading. Results for pole tide effects are given for various earth models with attention to the role of boundary constraints. A dynamic effect is identified which lengthens the Chandler period by about 1 day more than static lengthening, a contribution that suggests a vigorous low-frequency response. The values derived are shown to agree with previous models that do not incorporate the effects of the pole tide.

Comparison of the Jovian north and south pole aurorae using the IUE observatory

NASA Technical Reports Server (NTRS)

Skinner, T. E.; Moos, H. W.

1984-01-01

New results on the spatial and temporal variability of the auroral emissions from Jupiter have been obtained from three IUE observations of the south pole made during the period July 1983 to March 1984. The current observations, together with previous IUE studies of the north pole aurora, provide convincing evidence for persistent longitudinal asymmetries in the Jovian auroral emissions. The strongest emissions appear to originate from regions centered near lambda-III of about 0 deg at the south pole and lambda-III of about 185 deg at the north pole. Differences in surface magnetic field strength seem inadequate to explain the extent to which particles precipitating along field lines into a given longitude sector in one hemisphere are inhibited from precipitating along the same field lines into the opposite hemisphere. Thus, the IUE auroral results present a challenge to existing models of auroral production.

A Study of a Mulilayer BPF with Attenuation Poles by Using Folded Resonators with Open-Circuited End

NASA Astrophysics Data System (ADS)

Kasamai, Masashi; Usie, Masahiko; Wada, Kouji

We propose a multilayer bandpass filter(BPF) with attenuation poles using folded resonators with open-circuited end. Firstly, the basic characteristics of a folded resonator with open-circuited end under the change of the parameters is examined by an electromagnetic simulator. Secondly, 3-pole multilayer BPFs using the resonators above are proposed, simulated and experimented. As a result, the bandpass characteristics with attenuation poles near the lower and higher side of the center frequency is realized by the proposed structure.

Activity Cycles in Stars

NASA Technical Reports Server (NTRS)

Hathaway, David H.

2009-01-01

Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.

Formation of a Bright Polar Hood over the Summer North Pole of Saturn in 2016

NASA Astrophysics Data System (ADS)

Sayanagi, Kunio M.; Blalock, John J.; Ingersoll, Andrew P.; Dyudina, Ulyana A.; Ewald, Shawn P.

2016-10-01

We report that a bright polar hood has formed over the north pole of Saturn, seen first in images captured by the Cassini ISS camera in 2016. When the north pole was observed during the previous period of Cassini spacecraft's high-inclination orbits in 2012-2013, the concentration of light-scattering aerosols within 2-degree latitude of the north pole appeared to be less than that of the surrounding region, and appeared as a dark hole in all ISS filters, in particular in the shorter wavelength filters BL1 (460 nm), and VIO (420 nm). The north pole's appearance in 2012 was in contrast to that of the south pole in 2007, when the south pole had a bright polar hood in those short wavelengths; the south pole appeared dark in all other ISS filters in 2007. The difference between the south pole in 2007 and the north pole in 2012 was interpreted to be seasonal; in 2007, Saturn was approaching the equinox of 2009 and the south pole had been continuously illuminated since the previous equinox in 1995. In 2012, the north pole had been illuminated for only ~3 years after the long winter polar night. The bright hood over the summer south pole in 2007 was hypothesized to consist of aerosols produced by ultraviolet photodissociation of hydrocarbon molecules. Fletcher et al (2015) predicted that a similar bright hood should form over the north pole as Saturn approaches the 2017 solstice. In 2016, the Cassini spacecraft raised its orbital inclination again in preparation for its Grande Finale phase of the mission, from where it has a good view of the north pole. New images captured in 2016 show that the north pole has developed a bright polar hood. We present new images of the north polar region captured in 2016 that show the north pole, and other seasonally evolving high-latitude features including the northern hexagon. Our research has been supported by the Cassini Project, NASA grants OPR NNX11AM45G, CDAPS NNX15AD33G PATM NNX14AK07G, and NSF grant AAG 1212216.

Asteroid shapes and pole orientation from visual and infrared photometry

NASA Technical Reports Server (NTRS)

Tedesco, E. F.

1986-01-01

The shape and pole orientation of asteroid 16 Psyche was determined. New evidence supporting the shorter, five hour, period for 4 Vesta was presented. The first mutual eclipse event between Pluto and Charon was detected. The organization of an international campaign to obtain lightcurves and other data on the Pluto-Charon mutual events was started.

Pole movement in electronic and optoelectronic oscillators

NASA Astrophysics Data System (ADS)

Chatterjee, S.; Pal, S.; Biswas, B. N.

2013-12-01

An RLC circuit with poles on the left half of the complex frequency plane is capable of executing transient oscillations. During this period, energy conversion from potential to kinetic and from kinetic to potential continuously goes on, until the stored energy is lost in dissipation through the resistance. On the other hand, in an electronic or opto-electronic oscillator with an embedded RLC circuit, the poles are forcibly placed on the right-half plane (RHP) and as far as practicable away from the imaginary axis in order to help the growth of oscillation as quickly as possible. And ultimately, it is imagined that, like the case of an ideal linear harmonic oscillator, the poles are frozen on the imaginary axis so that the oscillation neither grows nor decays. The authors feel that this act of holding the poles right on the imaginary axis is a theoretical conjecture in a soft or hard self-excited oscillator. In this article, a detailed discussion on pole movement in an electronic and opto-electronic oscillator is carried out from the basic concept. A new analytical method for estimating the time-dependent part of the pole is introduced here.

A coronal hole and its identification as the source of a high velocity solar wind stream

NASA Technical Reports Server (NTRS)

Krieger, A. S.; Timothy, A. F.; Roelof, E. C.

1973-01-01

X-ray images of the solar corona showed a magnetically open structure in the low corona which extended from N20W20 to the south pole. Analysis of the measured X-ray intensities shows the density scale heights within the structure to be typically a factor of two less than that in the surrounding large scale magnetically closed regions. The structure is identified as a coronal hole. Wind measurements for the appropriate period were traced back to the sun by the method of instantaneous ideal spirals. A striking agreement was found between the Carrington longitude of the solar source of a recurrent high velocity solar wind stream and the position of the hole.

Periodically poled potassium niobate for second-harmonic generation at 463 nm.

PubMed

Meyn, J P; Klein, M E; Woll, D; Wallenstein, R; Rytz, D

1999-08-15

We report on the fabrication and characterization of quasi-phase-matched potassium niobate crystals for second-harmonic generation. Periodic 30-mum -pitch antiparallel ferroelectric domains are fabricated by means of poling in an electrical field. Both birefrigence and periodic phase shift of the generated second harmonic contribute to phase matching when the d(31) nonlinear optical tensor element is used. 3.8 mW of second-harmonic radiation at 463 nm is generated by frequency doubling of the output of master-oscillator power-amplifier diode laser in a 5-mm-long crystal. The measured effective nonlinear coefficient is 3.7pm/V. The measured spectral acceptance bandwidth of 0.25 nm corresponds to the theoretical value.

LRO-LAMP Observations of Illumination Conditions in the Lunar South Pole: Multi-Dataset and Model Comparison

NASA Astrophysics Data System (ADS)

Mandt, Kathleen; Mazarico, Erwan; Greathouse, Thomas K.; Byron, Ben; Retherford, Kurt D.; Gladstone, Randy; Liu, Yang; Hendrix, Amanda R.; Hurley, Dana; Stickle, Angela; Wes Patterson, G.; Cahill, Joshua; Williams, Jean-Pierre

2017-10-01

The south pole of the Moon is an area of great interest for exploration and scientific research because many low-lying regions are permanently shaded and are likely to trap volatiles for extended periods of time, while adjacent topographic highs can experience extended periods of sunlight. One of the goals of the Lunar Reconnaissance Orbiter (LRO) mission is to characterize the temporal variability of illumination of the lunar polar regions for the benefit of future exploration efforts. We use far ultraviolet (FUV) observations made by the Lyman Alpha Mapping Project (LAMP) to evaluate illumination at the lunar south pole (within 5° of the pole).LAMP observations are made through passive remote sensing in the FUV wavelength range of 57-196 nm using reflected sunlight during daytime observations and reflected light from the IPM and UV-bright stars during nighttime observations. In this study we focused on the region within 5° of the pole, and produced maps using nighttime data taken between September 2009 and February 2014. Summing over long time periods is necessary to obtain sufficient signal to noise. Many of the maps produced for this study show excess brightness in the “Off Band”, or 155-190 nm, because sunlight scattered into the PSRs is most evident in this wavelength range.LAMP observes the highest rate of scattered sunlight in two large PSRs during nighttime observations: Haworth and Shoemaker. We focus on these craters for comparisons with an illumination model and other LRO datasets. We find that the observations of scattered sunlight do not agree with model predictions. However, preliminary results comparing LAMP maps with other LRO datasets show a correlation between LAMP observations of scattered sunlight and Diviner measurements for maximum temperature.

Periodic domain inversion in x-cut single-crystal lithium niobate thin film

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

Mackwitz, P., E-mail: peterm@mail.upb.de; Rüsing, M.; Berth, G.

2016-04-11

We report the fabrication of periodically poled domain patterns in x-cut lithium niobate thin-film. Here, thin films on insulator have drawn particular attention due to their intrinsic waveguiding properties offering high mode confinement and smaller devices compared to in-diffused waveguides in bulk material. In contrast to z-cut thin film lithium niobate, the x-cut geometry does not require back electrodes for poling. Further, the x-cut geometry grants direct access to the largest nonlinear and electro-optical tensor element, which overall promises smaller devices. The domain inversion was realized via electric field poling utilizing deposited aluminum top electrodes on a stack of LNmore » thin film/SiO{sub 2} layer/Bulk LN, which were patterned by optical lithography. The periodic domain inversion was verified by non-invasive confocal second harmonic microscopy. Our results show domain patterns in accordance to the electrode mask layout. The second harmonic signatures can be interpreted in terms of spatially, overlapping domain filaments which start their growth on the +z side.« less

Integrated 3D printing and corona poling process of PVDF piezoelectric films for pressure sensor application

NASA Astrophysics Data System (ADS)

Kim, Hoejin; Torres, Fernando; Wu, Yanyu; Villagran, Dino; Lin, Yirong; Tseng, Tzu-Liang(Bill

2017-08-01

This paper presents a novel process to fabricate piezoelectric films from polyvinylidene fluoride (PVDF) polymer using integrated fused deposition modeling (FDM) 3D printing and corona poling technique. Corona poling is one of many effective poling processes that has received attention to activate PVDF as a piezoelectric responsive material. The corona poling process occurs when a PVDF polymer is exposed to a high electric field created and controlled through an electrically charged needle and a grid electrode under heating environment. FDM 3D printing has seen extensive progress in fabricating thermoplastic materials and structures, including PVDF. However, post processing techniques such as poling is needed to align the dipoles in order to gain piezoelectric properties. To further simplify the piezoelectric sensors and structures fabrication process, this paper proposes an integrated 3D printing process with corona poling to fabricate piezoelectric PVDF sensors without post poling process. This proposed process, named ‘Integrated 3D Printing and Corona poling process’ (IPC), uses the 3D printer’s nozzle and heating bed as anode and cathode, respectively, to create poling electric fields in a controlled heating environment. The nozzle travels along the programmed path with fixed distance between nozzle tip and sample’s top surface. Simultaneously, the electric field between the nozzle and bottom heating pad promotes the alignment of dipole moment of PVDF molecular chains. The crystalline phase transformation and output current generated by printed samples under different electric fields in this process were characterized by a Fourier transform infrared spectroscopy and through fatigue load frame. It is demonstrated that piezoelectric PVDF films with enhanced β-phase percentage can be fabricated using the IPC process. In addition, mechanical properties of printed PVDF was investigated by tensile testing. It is expected to expand the use of additive manufacturing to fabricate piezoelectric PVDF-based devices for applications such as sensing and energy harvesting.

Secular Orbit and Spin Variations of Asteroid (16) Psyche

NASA Astrophysics Data System (ADS)

Bills, B. G.; Park, R. S.; Scott, B.

2016-12-01

The obliquity, or angular separation between spin and orbit poles, of asteroid (16) Psyche is currently 95 degrees. We are interested in knowing how much that angular separation varies, on time scales of 104 to 106 years. To answer that question, we have done several related analyses. On short time scales, the orbital element variations of Psyche are dominated by perturbations from Jupiter. Jupiter's dominance has two basic causes: first is the large mass and relatively close position of Jupiter, and second is a 19:8 mean motion resonance. Jupiter completes 8 orbits in 94.9009 years, while Psyche takes 94.9107 years to complete 19 orbits. As a result of this, all of the orbital elements of Psyche exhibit significant periodic variations, with a 94.9 year period dominating. There are also significant variations at the synodic period, which is 8.628 years, or 1/11 of the resonant period. Over a 1000 year time span, centered on the present, the eccentricity varies from 0.133 to 0.140, and the inclination varies from 2.961 to 3.229 degrees. On longer time scales, the orbital elements of Psyche vary considerably more than that, due to secular perturbations from the planets. The secular variations are modeled as the response of interacting mass rings, rather than point masses. Again, Jupiter is the main perturbing influence on Psyche. The eccentricity and inclination both oscillate, with dominant periods of 18.667 kyr. The range of values seen over a million year time span, is 0.057 to 0.147 for eccentricity, and 0.384 to 4.777 degrees for inclination. Using a recent shape model, and assumption of uniform density, to constrain relevant moments of inertia, we estimate the spin pole precession rate parameter to be 8.53 arcsec/year. The current spin pole is at ecliptic {lon, lat} = { 32, -7} deg, whereas the orbit pole is at {lon, lat} = {60.47, 86.91} deg. The current obliquity is thus 94.3 degree. Using nominal values of the input parameters, the recovered spin pole trajectory is such that, over a million year time span, centered on the present, the minimum and maximum values of obliquity are 92.36 and 98.56 deg. The obliquity oscillates with dominant periods of 18.45 and 48.40 kyr.

A Quarter-Century of Observations of Comet 10P/Tempel 2 at Lowell Observatory

NASA Astrophysics Data System (ADS)

Schleicher, David G.; Knight, M. M.; Farnham, T. L.; Schwieterman, E. W.; Christensen, S. R.

2012-10-01

We report on our multi-epoch observations of Comet 10P/Tempel 2, primarily from Lowell Observatory. We obtained narrowband photometry during the 1983, 1988, 1999, and 2010 apparitions. Tempel 2 exhibited a rapid “turn-on” in activity 90 days prior to perihelion, with the date of turn on varying somewhat from apparition to apparition. Peak production was achieved 20 days after perihelion, with production decreasing gradually thereafter. The composition was “typical,” in agreement with our own earlier work as well as those of other authors. We also obtained 17 nights of imaging in 1999 and 29 nights of imaging in 2010/11. Tempel 2 exhibited a single, fan-like jet in both gas and dust images. The orientation of the jet varied due to changing viewing geometry during each apparition, but there was little to no change in jet morphology during a rotation period, implying that the source region producing it is near the pole. The pole solutions derived from R and CN data differ systematically, and we adopt RA=162°, Dec=+58° as the preferred solution for the ensemble. Numerical Monte Carlo jet modeling of the faint corkscrew structure evident in some CN images yields a source located only 10° from the pole and having a radius of about 10°, consistent with the source size needed to produce the measured water production. We measured the nucleus lightcurve on 15 nights from 2010 September through 2011 January. This yielded a nucleus rotation period of 8.950±0.002 hr, distinctly different from the rotation periods in 1999 (8.941±0.002 hr) and 1988 (8.932±0.001 hr). This continued spin-down marks only the second time a comet nucleus has been shown to sustain a change in period over multiple apparitions, and is presumably due to asymmetric torquing caused by outgassing. Support was provided by NASA Planetary Astronomy grants NNX09AB51G and NNX11AD95G.

Vibration Monitoring of Power Distribution Poles

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

Clark Scott; Gail Heath; John Svoboda

2006-04-01

Some of the most visible and least monitored elements of our national security infrastructure are the poles and towers used for the distribution of our nation’s electrical power. Issues surrounding these elements within the United States include safety such as unauthorized climbing and access, vandalism such as nut/bolt removal or destructive small arms fire, and major vandalism such as the downing of power poles and towers by the cutting of the poles with a chainsaw or torches. The Idaho National Laboratory (INL) has an ongoing research program working to develop inexpensive and sensitive sensor platforms for the monitoring and characterizationmore » of damage to the power distribution infrastructure. This presentation covers the results from the instrumentation of a variety of power poles and wires with geophone assemblies and the recording of vibration data when power poles were subjected to a variety of stimuli. Initial results indicate that, for the majority of attacks against power poles, the resulting signal can be seen not only on the targeted pole but on sensors several poles away in the distribution network and a distributed sensor system can be used to monitor remote and critical structures.« less

Crown Release Promotes Faster Diameter Growth of Pole-Size Black Walnut

Treesearch

Robert E. Phares; Robert D. Williams

1971-01-01

Complete crown release more than doubles the diameter growth of pole-size black walnut trees in southern Indiana over a 10-year period. Partially released trees gew about 50 percent more than unreleased trees. The faster growth of the released trees was directly related to increases in crown-area expansion. Most of the study trees produced bole sprouts; however, the...

Surface anatomy of major anatomical landmarks of the neck in an adult population: A Ct Evaluation of Vertebral Level.

PubMed

Badshah, Masroor; Soames, Roger; Ibrahim, Muhammad; Khan, Muhammad Jaffar; Khan, Adnan

2017-09-01

To compare the projectional surface anatomy of healthy individuals in an adult population with those with a thyroid mass, using computed tomography (CT). Sixteen slice CT images of 101 individuals were analyzed using a 32-bit Radiant DICOM viewer to establish the relationships among major anatomical landmarks in the neck and their vertebral levels. The structures investigated included: hard palate (HP), hyoid bone (HB) including body and lesser horns, soft palate (SP), thyroid gland (TG) (both superior and inferior poles), thyroid gland anteroposterior (APD) and superoinferior (SID) diameters, thyroid isthmus (TI) superoinferior dimension, epiglottis, vertebral arteries (right and left), and both right and left parotid glands (superior and inferior extents). The vertebral levels noted most frequently were: body of hyoid bone (C4, 42.71%); lesser horns of hyoid bone (C3, 36.46%); thyroid gland superior pole (C6, 31.25%); and thyroid gland inferior pole (T2, 30.2%). TG-ID, TG-APD, and TG-SID were not significantly different between males and females in the healthy group; however, there was a significant gender difference in thyroid gland inferior diameter in the pathology group [males 2.16(±1.16) vs. females 3.37(±1.30), P = 0.01, paired sample t-test]. Further studies are needed to determine whether neck pathology in those with a thyroid mass affects the dimensions of the thyroid gland. Moreover, the surface anatomy of the neck should be revisited using modern imaging techniques to address inconsistencies in anatomy and clinical reference texts. Clin. Anat. 30:781-787, 2017. © 2017Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Myxobacteria, Polarity, and Multicellular Morphogenesis

PubMed Central

Kaiser, Dale; Robinson, Mark; Kroos, Lee

2010-01-01

Myxobacteria are renowned for the ability to sporulate within fruiting bodies whose shapes are species-specific. The capacity to build those multicellular structures arises from the ability of M. xanthus to organize high cell-density swarms, in which the cells tend to be aligned with each other while constantly in motion. The intrinsic polarity of rod-shaped cells lays the foundation, and each cell uses two polar engines for gliding on surfaces. It sprouts retractile type IV pili from the leading cell pole and secretes capsular polysaccharide through nozzles from the trailing pole. Regularly periodic reversal of the gliding direction was found to be required for swarming. Those reversals are generated by a G-protein switch which is driven by a sharply tuned oscillator. Starvation induces fruiting body development, and systematic reductions in the reversal frequency are necessary for the cells to aggregate rather than continue to swarm. Developmental gene expression is regulated by a network that is connected to the suppression of reversals. PMID:20610548

A Mars environmental survey (MESUR) - Feasibility of a low cost global approach

NASA Technical Reports Server (NTRS)

Hubbard, G. S.; Wercinski, Paul F.; Sarver, George L.; Hanel, Robert P.; Ramos, Ruben

1991-01-01

In situ measurements of Mars' surface and atmosphere are the objectives of a novel network mission concept called the Mars Environmental SURvey (MESUR). As envisioned, the MESUR mission will emplace a pole-to-pole global distribution of 16 landers on the Martian surface over three launch opportunites using medium-lift (Delta-class) launch vehicles. The basic concept is to deploy small free-flying probes which would directly enter the Martian atmosphere, measure the upper atmospheric structure, image the local terrain before landing, and survive landing to perform meteorology, seismology, surface imaging, and soil chemistry measurements. Data will be returned via dedicated relay orbiter or direct-to-earth transmission. The mission philosophy is to: (1) 'grow' a network over a period of years using a series of launch opportunities; (2) develop a level-of-effort which is flexible and responsive to a broad set of objectives; (3) focus on Mars science while providing a solid basis for future human presence; and (4) minimize overall project cost and complexity wherever possible.

Aperture scaling effects with monolithic periodically poled lithium niobate optical parametric oscillators and generators.

PubMed

Missey, M; Dominic, V; Powers, P; Schepler, K L

2000-02-15

We used elliptical beams to demonstrate aperture scaling effects in nanosecond single-grating and multigrating periodically poled lithium niobate (PPLN) monolithic optical parametric oscillators and generators. Increasing the cavity Fresnel number in single-grating crystals broadened both the beam divergence and the spectral bandwidth. Both effects are explained in terms of the phase-matching geometry. These effects are suppressed when a multigrating PPLN crystal is used because the individual gratings provide small effective subapertures. A flood-pumped multigrating optical parametric generator displayed a low output beam divergence and contained 19 pairs of signal and idler frequencies.

Efficient high-power frequency doubling of distributed Bragg reflector tapered laser radiation in a periodically poled MgO-doped lithium niobate planar waveguide.

PubMed

Jedrzejczyk, Daniel; Güther, Reiner; Paschke, Katrin; Jeong, Woo-Jin; Lee, Han-Young; Erbert, Götz

2011-02-01

We report on efficient single-pass, high-power second-harmonic generation in a periodically poled MgO-doped LiNbO3 planar waveguide using a distributed Bragg reflector tapered diode laser as a pump source. A coupling efficiency into the planar waveguide of 73% was realized, and 1.07 W of visible laser light at 532 nm was generated. Corresponding optical and electro-optical conversion efficiencies of 26% and 8.4%, respectively, were achieved. Good agreement between the experimental data and the theoretical predictions was observed.

Modal expansions in periodic photonic systems with material loss and dispersion

NASA Astrophysics Data System (ADS)

Wolff, Christian; Busch, Kurt; Mortensen, N. Asger

2018-03-01

We study band-structure properties of periodic optical systems composed of lossy and intrinsically dispersive materials. To this end, we develop an analytical framework based on adjoint modes of a lossy periodic electromagnetic system and show how the problem of linearly dependent eigenmodes in the presence of material dispersion can be overcome. We then formulate expressions for the band-structure derivative (∂ ω )/(∂ k ) (complex group velocity) and the local and total density of transverse optical states. Our exact expressions hold for 3D periodic arrays of materials with arbitrary dispersion properties and in general need to be evaluated numerically. They can be generalized to systems with two, one, or no directions of periodicity provided the fields are localized along nonperiodic directions. Possible applications are photonic crystals, metamaterials, metasurfaces composed of highly dispersive materials such as metals or lossless photonic crystals, and metamaterials or metasurfaces strongly coupled to resonant perturbations such as quantum dots or excitons in 2D materials. For illustration purposes, we analytically evaluate our expressions for some simple systems consisting of lossless dielectrics with one sharp Lorentzian material resonance added. By combining several Lorentz poles, this provides an avenue to perturbatively treat quite general material loss bands in photonic crystals.

Nordic walking versus walking without poles for rehabilitation with cardiovascular disease: Randomized controlled trial.

PubMed

Girold, Sébastien; Rousseau, Jérome; Le Gal, Magalie; Coudeyre, Emmanuel; Le Henaff, Jacqueline

2017-07-01

With Nordic walking, or walking with poles, one can travel a greater distance and at a higher rate than with walking without poles, but whether the activity is beneficial for patients with cardiovascular disease is unknown. This randomized controlled trial was undertaken to determine whether Nordic walking was more effective than walking without poles on walk distance to support rehabilitation training for patients with acute coronary syndrome (ACS) and peripheral arterial occlusive disease (PAOD). Patients were recruited in a private specialized rehabilitation centre for cardiovascular diseases. The entire protocol, including patient recruitment, took place over 2 months, from September to October 2013. We divided patients into 2 groups: Nordic Walking Group (NWG, n=21) and Walking Group without poles (WG, n=21). All patients followed the same program over 4 weeks, except for the walk performed with or without poles. The main outcome was walk distance on the 6-min walk test. Secondary outcomes were maximum heart rate during exercise and walk distance and power output on a treadmill stress test. We included 42 patients (35 men; mean age 57.2±11 years and BMI 26.5±4.5kg/m 2 ). At the end of the training period, both groups showed improved walk distance on the 6-min walk test and treatment stress test as well as power on the treadmill stress test (P<0.05). The NWG showed significantly greater walk distance than the WG (P<0.05). Both ACS and PAOD groups showed improvement, but improvement was significant for only PAOD patients. After a 4-week training period, Nordic walking training appeared more efficient than training without poles for increasing walk distance on the 6-min walk test for patients with ACS and PAOD. Copyright © 2017. Published by Elsevier Masson SAS.

The effect of the Earth's oblateness on the Moon's physical libration in latitude

NASA Astrophysics Data System (ADS)

Kondratyev, B. P.

2013-05-01

The Moon's physical libration in latitude generated by gravitational forces caused by the Earth's oblateness has been examined by a vector analytical method. Libration oscillations are described by a close set of five linear inhomogeneous differential equations, the dispersion equation has five roots, one of which is zero. A complete solution is obtained. It is revealed that the Earth's oblateness: a) has little effect on the instantaneous axis of Moon's rotation, but causes an oscillatory rotation of the body of the Moon with an amplitude of 0.072″ and pulsation period of 16.88 Julian years; b) causes small nutations of poles of the orbit and of the ecliptic along tight spirals, which occupy a disk with a cut in a center and with radius of 0.072″. Perturbations caused by the spherical Earth generate: a) physical librations in latitude with an amplitude of 34.275″; b) nutational motion for centers of small spiral nutations of orbit (ecliptic) pole over ellipses with semi-major axes of 113.850″ (85.158″) and the first pole rotates round the second one along a circle with radius of 28.691″; c) nutation of the Moon's celestial pole over an ellipse with a semi-major axis of 45.04″ and with an axes ratio of about 0.004 with a period of T = 27.212 days. The principal ellipse's axis is directed tangentially with respect to the precession circumference, along which the celestial pole moves nonuniformly nearly in one dimension. In contrast to the accepted concept, the latitude does not change while the Moon's poles of rotation move. The dynamical reason for the inclination of the Moon's mean equator with respect to the ecliptic is oblateness of the body of the Moon.

Periodically poled silicon

NASA Astrophysics Data System (ADS)

Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

2010-02-01

Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

Tunable ultraviolet radiation by second-harmonic generation in periodically poled lithium tantalate.

PubMed

Meyn, J P; Fejer, M M

1997-08-15

We describe electric-field poling of fine-pitch ferroelectric domain gratings in lithium tantalate and characterization of nonlinear-optical properties by single-pass quasi-phase-matched second-harmonic generation (QPM SHG). With a 7.5-microm-period grating, the observed effective nonlinear coefficient for first-order QPM SHG of 532-nm radiation is 9 pm/V, whereas for a grating with a 2.625-microm period, 2.6 pm/V was observed for second-order QPM SHG of 325-nm radiation. These values are 100% and 55% of the theoretically expected values, respectively. We derive a temperature-dependent Sellmeier equation for lithium tantalate that is valid deeper into the UV than currently available results, based on temperature-tuning experiments at different QPM grating periods combined with refractive-index data in the literature.

Electric field poling induced self-biased converse magnetoelectric response in PMN-PT/NiFe2O4 nanocomposites

NASA Astrophysics Data System (ADS)

Ahlawat, Anju; Satapathy, S.; Deshmukh, Pratik; Shirolkar, M. M.; Sinha, A. K.; Karnal, A. K.

2017-12-01

In this letter, studies on structural transitions and the effect of electric field poling on magnetoelectric (ME) properties in 0.65Pb (Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-PT)/NiFe2O4 (NFO) nanocomposites are reported. The composite illustrates dramatic changes in the NFO crystal structure across ferroelectric transition temperature [Curie temperature (Tc) ˜ 450 K] of PMN-PT, while pure NFO does not exhibit any structural change in the temperature range (300 K-650 K). Synchrotron based X-ray diffraction analysis revealed the splitting of NFO peaks across the Tc of PMN-PT in the PMN-PT/NFO composite. Consequently, the anomalies are observed in temperature dependent magnetization of the NFO phase at the Tc of PMN-PT, establishing ME coupling in the PMN-PT/NFO composite. Furthermore, the composite exhibits drastic modification in ME coupling under electrically poled and unpoled conditions. A large self-biased ME effect characterized by non-zero ME response at zero Hbias was observed in electrically poled composites, which was not observed in unpoled PMN-PT/NFO. These results propose an alternative mechanism for intrinsic converse ME effects. The maximum magnetoelectric output was doubled after electrical poling. The observed self-biased converse magnetoelectric effect at room temperature provides potential applications in electrically controlled memory devices and magnetic flux control devices.

Electric field induced cubic to monoclinic phase transition in multiferroic 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} solid solution

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

Pandey, Rishikesh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com

2014-10-20

The results of x-ray diffraction studies on 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} solid solution poled at various electric fields are presented. After poling, significant value of planar electromechanical coupling coefficient (k{sub P}) is observed for this composition having cubic structure in unpoled state. The cubic structure of 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} transforms to monoclinic structure with space group Pm for the poling field ≥5 kV/cm. Large c-axis microscopic lattice strain (1.6%) is achieved at 30 kV/cm poling field. The variation of the c-axis strain and unit cell volume with poling field shows a drastic jump similar to that observed for strainmore » versus electric field curve in (1 − x)Pb(Mg{sub 1/3}Nb{sub 2/3}) O{sub 3}-xPbTiO{sub 3} and (1 − x)Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3}.« less

The puzzling case of asteroid 8 Flora solved

NASA Technical Reports Server (NTRS)

Di Martino, M.; Zappala, V.; Cellino, A.; Barucci, M. A.; Harris, A. W.; Young, J. W.

1989-01-01

This paper reports the results obtained in an international campaign devoted to the observations of the asteroid 8 Flora, a possible target of the Vesta mission. Using the lightcurves obtained during three oppositions (1980, 1983, 1984), a synodic rotational period of 12.87 hours was determined. This period, applied to the lightcurves of 8 Flora already published, satisfactorily explains these observations. Applying the AM-method described by Zappala et al. (1983), the pole position was calculated. The slope parameter G, determined during the 1969 and 1983 apparitions, differs by about 0.10. Considering that in those years the ecliptic longitudes of the asteroid were about 115 degrees apart, this fact probably indicates the presence of variations in the structure and chemical compositions of the surface.

Seasonal Evolution of Titan's Stratosphere Near the Poles

NASA Astrophysics Data System (ADS)

Coustenis, A.; Jennings, D. E.; Achterberg, R. K.; Bampasidis, G.; Nixon, C. A.; Lavvas, P.; Cottini, V.; Flasar, F. M.

2018-02-01

In this Letter, we report the monitoring of seasonal evolution near Titan’s poles. We find Titan’s south pole to exhibit since 2010 a strong temperature decrease and a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously only observed at high northern latitudes. This results from the seasonal change on Titan going from winter (2002) to summer (2017) in the north and, at the same time, the onset of winter in the south pole. During this transition period atmospheric components with longer chemical lifetimes linger in the north, undergoing slow photochemical destruction, while those with shorter lifetimes decrease and reappear in the south. An opposite effect was expected in the north, but not observed with certainty until now. We present here an analysis of high-resolution nadir spectra acquired by Cassini/Cassini Composite Infrared Spectrometer in the past years and describe the temperature and composition variations near Titan’s poles. From 2013 until 2016, the northern polar region has shown a temperature increase of 10 K, while the south has shown a more significant decrease (up to 25 K) in a similar period of time. While the south polar region has been continuously enhanced since about 2012, the chemical content in the north is finally showing a clear depletion for most molecules only since 2015. This is indicative of a non-symmetrical response to the seasons in Titan’s stratosphere that can set constraints on photochemical and GCM models.

High performance hybrid magnetic structure for biotechnology applications

DOEpatents

Humphries, David E; Pollard, Martin J; Elkin, Christopher J

2005-10-11

The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetizable molecular structures and targets. Also disclosed are: a method of assembling the hybrid magnetic plates, a high throughput protocol featuring the hybrid magnetic structure, and other embodiments of the ferromagnetic pole shape, attachment and adapter interfaces for adapting the use of the hybrid magnetic structure for use with liquid handling and other robots for use in high throughput processes.

High performance hybrid magnetic structure for biotechnology applications

DOEpatents

Humphries, David E.; Pollard, Martin J.; Elkin, Christopher J.

2006-12-12

The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides for separation and other biotechnology applications involving holding, manipulation, or separation of magnetic or magnetizable molecular structures and targets. Also disclosed are: a method of assembling the hybrid magnetic plates, a high throughput protocol featuring the hybrid magnetic structure, and other embodiments of the ferromagnetic pole shape, attachment and adapter interfaces for adapting the use of the hybrid magnetic structure for use with liquid handling and other robots for use in high throughput processes.

Polymer poling characterization using second harmonic generation (SHG)

NASA Astrophysics Data System (ADS)

Tellier, Gildas; Averty, Dominique; Blart, Errol; Boisrobert, Christian; Gundel, Hartmut; Le Tacon, Sylvain; Monnereau, Cyrille; Odobel, Fabrice; Seveno, Raynald

2006-04-01

Several polymer molecules have structures which are suitable for the non-linear optic applications. We report on the design and fabrication of a high performance electro-optic modulator made of polymer thin films. The polymer we study contains a chromophore based on Disperse Red One covalently grafted to a host-matrix. The polymer materials are deposited in thin layers on a glass substrate by chemical solution deposition, either by spin-coating or by dip-coating. The thickness of the films is ranging from a hundred nanometers to several micrometers. Initially, the polymer molecules are randomly oriented and the films are isotropic, hence no electro-optic effect can be observed. In order to break the symmetry and align the chromophores, the films are submitted to the so-called corona poling process. As a result, their structure become non-centrosymmetric and the second-order susceptibility is no longer zero. The corona poling method consists of applying a high electric field to the polymer by means of a needle electrode, placed above the polymer film which is posed on a grounded sample support electrode. Thermal regulation of the support electrode allows to control the temperature during the poling of the films. Once the poling process has been established, a chemical cross-linking function is thermally activated in order to fix the orientation of the chromophores in the polymer matrix. The orientation and its stability in time is evaluated with a Second Harmonic Generation measurement set-up using the Makers Fringes configuration. We studied the influence of the poling temperature, the distance between the corona needle electrode and the sample, the high voltage applied, and the duration of the poling process on the efficiency of chromophore orientation in order to optimize the poling procedure. Finally, aging of poled polymer samples has been investigated at elevated temperatures, confirming the stability of the cross-linking process.

Microtubule Flux and Sliding in Mitotic Spindles of Drosophila EmbryosV⃞

PubMed Central

Brust-Mascher, Ingrid; Scholey, Jonathan M.

2002-01-01

We proposed that spindle morphogenesis in Drosophila embryos involves progression through four transient isometric structures in which a constant spacing of the spindle poles is maintained by a balance of forces generated by multiple microtubule (MT) motors and that tipping this balance drives pole-pole separation. Here we used fluorescent speckle microscopy to evaluate the influence of MT dynamics on the isometric state that persists through metaphase and anaphase A and on pole-pole separation in anaphase B. During metaphase and anaphase A, fluorescent punctae on kinetochore and interpolar MTs flux toward the poles at 0.03 μm/s, too slow to drive chromatid-to-pole motion at 0.11 μm/s, and during anaphase B, fluorescent punctae on interpolar MTs move away from the spindle equator at the same rate as the poles, consistent with MT-MT sliding. Loss of Ncd, a candidate flux motor or brake, did not affect flux in the metaphase/anaphase A isometric state or MT sliding in anaphase B but decreased the duration of the isometric state. Our results suggest that, throughout this isometric state, an outward force exerted on the spindle poles by MT sliding motors is balanced by flux, and that suppression of flux could tip the balance of forces at the onset of anaphase B, allowing MT sliding and polymerization to push the poles apart. PMID:12429839

Role of Housing Reconstruction Between Years 2000 - 2014 in Merging of Urban Structure of The North East Wrocław / Rola Zabudowy Mieszkaniowej z Lat 2000-2014 w Scalaniu Struktury Urbanistycznej Północno-Wschodniego Wrocławia

NASA Astrophysics Data System (ADS)

Masztalski, Robert; Michalski, Marcin

2016-03-01

The article presents the urban structure of the North-East of Wroclaw, where in the vicinity of the historic buildings and residential buildings from the 70s of the last century, and between, in the last 20 years there were built new buildings, as binding material of the urban structure. The new multifamily housing development of years 2000-2014 of Psie Pole as a housing development in Wroclaw, closes the gap between the historic district residential buildings in the old Psie Pole and the buildings of large slabs of the 70s of the twentieth century. The contemporary residential development uses the existing social infrastructure centre of the old Psie Pole district, and also the social infrastructure of the housing development of 70s of the twentieth century. The authors analyze, in the first part, the spatial development of these areas on the basis of historical materials. In the following, based on an analysis of urban structure created in the last 15 years of development, analyze existing conditions, context and value (in terms of urban planning - the wealth of social infrastructure), the contemporary housing development of Psie Pole.

Particle-in-cell simulations of Earth-like magnetosphere during a magnetic field reversal

NASA Astrophysics Data System (ADS)

Barbosa, M. V. G.; Alves, M. V.; Vieira, L. E. A.; Schmitz, R. G.

2017-12-01

The geologic record shows that hundreds of pole reversals have occurred throughout Earth's history. The mean interval between the poles reversals is roughly 200 to 300 thousand years and the last reversal occurred around 780 thousand years ago. Pole reversal is a slow process, during which the strength of the magnetic field decreases, become more complex, with the appearance of more than two poles for some time and then the field strength increases, changing polarity. Along the process, the magnetic field configuration changes, leaving the Earth-like planet vulnerable to the harmful effects of the Sun. Understanding what happens with the magnetosphere during these pole reversals is an open topic of investigation. Only recently PIC codes are used to modeling magnetospheres. Here we use the particle code iPIC3D [Markidis et al, Mathematics and Computers in Simulation, 2010] to simulate an Earth-like magnetosphere at three different times along the pole reversal process. The code was modified, so the Earth-like magnetic field is generated using an expansion in spherical harmonics with the Gauss coefficients given by a MHD simulation of the Earth's core [Glatzmaier et al, Nature, 1995; 1999; private communication to L.E.A.V.]. Simulations show the qualitative behavior of the magnetosphere, such as the current structures. Only the planet magnetic field was changed in the runs. The solar wind is the same for all runs. Preliminary results show the formation of the Chapman-Ferraro current in the front of the magnetosphere in all the cases. Run for the middle of the reversal process, the low intensity magnetic field and its asymmetrical configuration the current structure changes and the presence of multiple poles can be observed. In all simulations, a structure similar to the radiation belts was found. Simulations of more severe solar wind conditions are necessary to determine the real impact of the reversal in the magnetosphere.

Laser-induced ferroelectric domain engineering in LiNbO3 crystals using an amorphous silicon overlayer

NASA Astrophysics Data System (ADS)

Zisis, G.; Martinez-Jimenez, G.; Franz, Y.; Healy, N.; Masaud, T. M.; Chong, H. M. H.; Soergel, E.; Peacock, A. C.; Mailis, S.

2017-08-01

We report laser-induced poling inhibition and direct poling in lithium niobate crystals (LiNbO3), covered with an amorphous silicon (a-Si) light-absorbing layer, using a visible (488 nm) continuous wave laser source. Our results show that the use of the a-Si overlayer produces deeper poling inhibited domains with minimum surface damage, as compared to previously reported UV laser writing experiments on uncoated crystals, thus increasing the applicability of this method in the production of ferroelectric domain engineered structures for nonlinear optical applications. The characteristics of the poling inhibited domains were investigated using differential etching and piezoresponse force microscopy.

Cross-cultural differences in psychosocial adaptation to isolated and confined environments.

PubMed

Palinkas, Lawrence A; Johnson, Jeffrey C; Boster, James S; Rakusa-Suszczewski, Stanislaw; Klopov, Valeri P; Fu, Xue Quan; Sachdeva, Usha

2004-11-01

Differences in patterns of psychosocial adaptation under conditions of prolonged isolation and confinement in Antarctica were examined to determine the extent to which they were influenced by national culture in general and the individualist-collectivist orientation of national cultures in particular. The Profile of Mood States and measures of structural and functional social support were administered over an 8-mo period (March through October) to 13 winter-over crews from 5 nations operating research stations in the Antarctic: United States (3 crews, n = 77), Poland (3 crews, n = 40), Russia (3 crews, n = 34), China (3 crews, n = 40), and India (1 crew, n = 26). Americans at South Pole Station reported significant increases in fatigue and anxiety and a significant decrease in vigor over the winter. During the same period, Russians at Vostok Station reported significant decreases in depression, anxiety, and confusion, and Indians at Maitri Station reported a significant decrease in anger. A significant decrease in social interaction with fellow crewmembers occurred at South Pole Station, Vostok Station, and Poland's Arctowski Station. Several differences were also observed between the five stations in correlations between mood scores and measures of structural and functional social support. An individualistic cultural orientation was significantly associated with low social support and low negative mood. Cultural background is associated with mood and social support as well as changes in these measures during the austral winter. Cultural differences in patterns of psychosocial adaptation must be considered in the formation and training of multinational crews for long duration missions in space.

GHOST balloons around Antarctica

NASA Technical Reports Server (NTRS)

Stearns, Charles R.

1988-01-01

The GHOST balloon position as a function of time data shows that the atmospheric circulation around the Antarctic Continent at the 100 mb and 200 mb levels is complex. The GHOST balloons supposedly follow the horizontal trajectory of the air at the balloon level. The position of GHOST balloon 98Q for a three month period in 1968 is shown. The balloon moved to within 2 deg of the South Pole on 1 October 1968 and then by 9 December 1968 was 35 deg from the South Pole and close to its position on 1 September 1968. The balloon generally moved from west to east but on two occasions moved in the opposite direction for a few days. The latitude of GHOST balloons 98Q and 149Z which was at 200 mb is given. Both balloons tended to get closer to the South Pole in September and October. Other GHOST balloons at the same pressure and time period may not indicate similar behavior.

Junocam Imaging Jupiter: Results from PJ1 through PJ8

NASA Astrophysics Data System (ADS)

Ravine, M. A.; Hansen, C. J.; Orton, G. S.; Momary, T. W.; Caplinger, M. A.; Atreya, S. K.; Ingersoll, A. P.; Bolton, S. J.; Tabataba-Vakili, F.; Rogers, J. H.; Eichstadt, G.

2017-09-01

Juno's imaging system, JunoCam, has acquired images of Jupiter's poles for each of the first eight orbits of the mission, providing a significant quantitative improvement in our coverage of Jupiter's poles and revealing very different atmospheric structure than at the lower latitudes.

WEST ELEVATION WITH GRADUATED MEASURING POLE. NOTE THE CIRCULAR OPENINGS ...

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

WEST ELEVATION WITH GRADUATED MEASURING POLE. NOTE THE CIRCULAR OPENINGS INTO THE UNDERGROUND PORTION OF THE STRUCTURE. VIEW FACING EAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

Effect of poling process on piezoelectric properties of BCZT - 0.08 wt.% CeO{sub 2} lead-free ceramics

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

Chandrakala, E.; Praveen, J. Paul; Das, Dibakar, E-mail: ddse@uohyd.ernet.in

2016-05-06

The properties of lead free piezoelectric materials can be tuned by suitable doping in the A and B sites of the perovskite structure. In the present study, cerium has been identified as a dopant to investigate the piezoelectric properties of lead-free BCZT system. BCZT – 0.08 wt.%CeO{sub 2} lead-free ceramics have been synthesized using sol-gel technique and the effects of CeO{sub 2} dopant on their phase structure and piezoelectric properties were investigated systematically. Poling conditions, such as temperature, electric field, and poling time have been optimized to get enhanced piezoelectric response. The optimized poling conditions (50°C, 3Ec and 30min) resultedmore » in high piezoelectric charge coefficient d{sub 33} ~ 670pC/N, high electromechanical coupling coefficient k{sub p} ~ 60% and piezoelectric voltage coefficient g{sub 33} ~ 14 mV.m/N for BCZT – 0.08wt.% CeO{sub 2} ceramics.« less

Detection of discoloration and decay in living trees and utility poles

Treesearch

Alex L. Shigo; Alex Shigo

1974-01-01

A method is described for detecting discoloration and decay in living trees and creosoted utility poles. The method and devices have come from research involving many people over a seven-year period. A probe was inserted into a 3/32-inch (2.4 mm) diameter hole made by drill bits 8 inches (20.32 cm) and 12 inches (30.48 cm) long mounted in a portable, light-weight,...

High-power, continuous-wave, second-harmonic generation at 532 nm in periodically poled KTiOPO(4).

PubMed

Samanta, G K; Kumar, S Chaitanya; Mathew, M; Canalias, C; Pasiskevicius, V; Laurell, F; Ebrahim-Zadeh, M

2008-12-15

We report efficient generation of high-power, cw, single-frequency radiation in the green in a simple, compact configuration based on single-pass, second-harmonic generation of a cw ytterbium fiber laser at 1064 nm in periodically poled KTiOPO(4). Using a crystal containing a 17 mm single grating with period of 9.01 microm, we generate 6.2 W of cw radiation at 532 nm for a fundamental power of 29.75 W at a single-pass conversion efficiency of 20.8%. Over the entire range of pump powers, the generated green output is single frequency with a linewidth of 8.5 MHz and has a TEM(00) spatial profile with M(2)<1.34. The demonstrated green power can be further improved by proper thermal management of crystal heating effects at higher pump powers and also by optimized design of the grating period to include thermal issues.

Finite Element Analysis of Doorframe Structure of Single Oblique Pole Type in Container Crane

NASA Astrophysics Data System (ADS)

Cheng, X. F.; Wu, F. Q.; Tang, G.; Hu, X.

2017-07-01

Compared with the composite type, the single oblique pole type has more advantages, such as simple structure, thrift steel and high safe overhead clearance. The finite element model of the single oblique pole type is established in nodes by ANSYS, and more details are considered when the model is simplified, such as the section of Girder and Boom, torque in Girder and Boom occurred by Machinery house and Trolley, density according to the way of simplification etc. The stress and deformation of ten observation points are compared and analyzed, when the trolley is in nine dangerous positions. Based on the result of analysis, six dangerous points are selected to provide reference for the detection and evaluation of container crane.

Structural stability and chaotic solutions of perturbed Benjamin-Ono equations

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

Birnir, B.; Morrison, P.J.

1986-11-01

A method for proving chaos in partial differential equations is discussed and applied to the Benjamin-Ono equation subject to perturbations. The perturbations are of two types: one that corresponds to viscous dissipation, the so-called Burger's term, and one that involves the Hilbert transform and has been used to model Landau damping. The method proves chaos in the PDE by proving temporal chaos in its pole solutions. The spatial structure of the pole solutions remains intact, but their positions are chaotic in time. Melnikov's method is invoked to show this temporal chaos. It is discovered that the pole behavior is verymore » sensitive to the Burger's perturbation, but is quite insensitive to the perturbation involving the Hilbert transform.« less

Climatic impact of glacial cycle polar motion: Coupled oscillations of ice sheet mass and rotation pole position

USGS Publications Warehouse

Bills, Bruce G.; James, Thomas S.; Mengel, John G.

1999-01-01

Precessional motion of Earth's rotation axis relative to its orbit is a well-known source of long-period climatic variation. It is less well appreciated that growth and decay of polar ice sheets perturb the symmetry of the global mass distribution enough that the geographic location of the rotation axis will change by at least 15 km and possibly as much as 100 km during a single glacial cycle. This motion of the pole will change the seasonal and latitudinal pattern of temperatures. We present calculations, based on a diurnal average energy balance, which compare the summer and winter temperature anomalies due to a 1° decrease in obliquity with those due to a 1° motion of the rotation pole toward Hudson Bay. Both effects result in peak temperature perturbations of about 1° Celsius. The obliquity change primarily influences the amplitude of the seasonal cycle, while the polar motion primarily changes the annual mean temperatures. The polar motion induced temperature anomaly is such that it will act as a powerful negative feedback on ice sheet growth. We also explore the evolution of the coupled system composed of ice sheet mass and pole position. Oscillatory solutions result from the conflicting constraints of rotational and thermal stability. A positive mass anomaly on an otherwise featureless Earth is in rotational equilibrium only at the poles or the equator. The two polar equilibria are rotationally unstable, and the equatorial equilibrium, though rotationally stable, is thermally unstable. We find that with a plausible choice for the strength of coupling between the thermal and rotational systems, relatively modest external forcing can produce significant response at periods of 104–106 years, but it strongly attenuates polar motion at longer periods. We suggest that these coupled oscillations may contribute to the observed dominance of 100 kyr glacial cycles since the mid-Pleistocene and will tend to stabilize geographic patterns that are suitable to glaciations.

Fault Current Distribution and Pole Earth Potential Rise (EPR) Under Substation Fault

NASA Astrophysics Data System (ADS)

Nnassereddine, M.; Rizk, J.; Hellany, A.; Nagrial, M.

2013-09-01

New high-voltage (HV) substations are fed by transmission lines. The position of these lines necessitates earthing design to ensure safety compliance of the system. Conductive structures such as steel or concrete poles are widely used in HV transmission mains. The earth potential rise (EPR) generated by a fault at the substation could result in an unsafe condition. This article discusses EPR based on substation fault. The pole EPR assessment under substation fault is assessed with and without mutual impedance consideration. Split factor determination with and without the mutual impedance of the line is also discussed. Furthermore, a simplified formula to compute the pole grid current under substation fault is included. Also, it includes the introduction of the n factor which determines the number of poles that required earthing assessments under substation fault. A case study is shown.

A Cold-Pole Enhancement in Mercury’s Sodium Exosphere

PubMed Central

Cassidy, Timothy A.; McClintock, William E.; Killen, Rosemary M.; Sarantos, Menelaos; Merkel, Aimee W.; Vervack, Ronald J.; Burger, Matthew H.

2018-01-01

The Ultraviolet and Visible Spectrometer (UVVS) component of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MESSENGER spacecraft characterized the local-time distribution of the sodium exosphere over the course of its orbital mission. The observations show that the sodium exosphere is enhanced above Mercury’s cold-pole longitudes. Based on previously published sodium exosphere models we infer that these regions act as nightside surface reservoirs, temporary sinks to the exosphere that collect sodium atoms transported anti-sunward. The reservoirs are revealed as exospheric enhancements when they are exposed to sunlight. As in the models the reservoir is depleted as the cold poles rotate from dawn to dusk, but unlike the models the depletion is only partial. The persistence of the reservoir means that it could, over the course of geologically long periods of time, contribute to an increase in the bulk concentration of sodium near the cold-pole longitudes. PMID:29720774

The 14 month wind stressed residual circulation (pole tide) in the North Sea

NASA Technical Reports Server (NTRS)

Oconnor, W. P.

1986-01-01

From published research it is known that a quasi-periodic 14 month atmospheric pressure oscillation of a few tenths of a millibar exists in the region of the North and Baltic Seas. At some time in the cycle the associated wind stress has a westerly component that drives a circulation in the North Sea. The results of a dynamical model and comparisons with several North Sea residual circulation studies show that a large sea level gradient results along the Dutch coast. It is this feature that has been referred to as the enhanced pole tide. The dynamical similarity of this pole tide in the North and Baltic Seas to the annual and seasonal wind forced circulations is considered. It is inferred that the large deviations of the pole tide from equilibrium at coastal stations are the result of this sea level set up forces by the 14 month wind stress cycle.

A New Quiet GSN Site at the South Pole: Comparison of Seismic Data Between SPA and QSPA.

NASA Astrophysics Data System (ADS)

Anderson, K. R.; Aster, R. C.; Butler, R.; Hutt, C.; Storm, T.; Anderson, D.; Vineyard, J. J.; Albert, D. G.

2003-12-01

Due to increasing noise from Amundsen-Scott South Pole Station (ASSPS), a new Global Seismic Network (GSN) station, QSPA, was constructed in the 2002-2003 field season to supplant the previous GSN station, SPA, in operation since c. 1985. QSPA is the first experiment established at the South Pole Remote Earth Science and Seismological Observatory (SPRESSO). The new instruments reside in the newly-designated seismic Quiet Sector, 8 km southeast of ASSPS. SPRESSO provides a much lower noise environment, yet is close enough to the south pole to be effectively co-sited with Earth's rotational axis for long-period seismological purposes. The SPRESSO site was selected after examining tractor surface noise propagation, balanced against power and communication considerations. Numerical modeling showed that ASSPS noise should be fairly well trapped in near-surface, lower-velocity firn zone and indicated that a burial depth of 300 m would very substantially reduce noise. QSPA consists of a Geotech Instruments KS-54000 at 275 m and Guralp CMG-3Tb at 255 m depth, separated horizontally by 10 m. These depths are approximately 160 m below the local firn/ice transition. QSPA also includes a near-surface vault ( ˜5 m depth) housing Streckeisen STS-1V and STS-2 sensors. SPA has been left in operation for a period of ˜1 yr to allow for a thorough comparison with QSPA. Although 8 km from the South Pole station activities, the QSPA site borehole instruments still sense South Pole noise. However, these noise levels are significantly diminished at frequencies >1 Hz and at periods >20 s. From 1 to 15 Hz, the improved noise environment is especially dramatic. For example, background noise at 2 Hz is 15 db below SPA, ˜20-25 dB at 3 Hz, ˜30-35 dB at 4Hz, and ˜35-40 dB above 5Hz. Between 2 and 10 Hz the QSPA Guralp borehole sensor shows data intervals with noise levels below the Peterson (1993) Low Noise Model (PLNM) (with minimum noise at ˜3Hz ˜12dB below PLNM), making the site among the quietest ever measured. The improvement in the long period (T > 20 s) band is ˜5-10 dB. Most significant noise reduction is seen in the vertical channels, although the horizontal data are improved as well.

Methods of producing strain in a semiconductor waveguide and related devices

DOEpatents

Cox, Johathan Albert; Rakich, Peter Thomas

2016-02-16

Quasi-phase matched (QPM), semiconductor photonic waveguides include periodically-poled alternating first and second sections. The first sections exhibit a high degree of optical coupling (abbreviated "X.sup.2"), while the second sections have a low X.sup.2. The alternating first and second sections may comprise high-strain and low-strain sections made of different material states (such as crystalline and amorphous material states) that exhibit high and low X.sup.2 properties when formed on a particular substrate, and/or strained corrugated sections of different widths. The QPM semiconductor waveguides may be implemented as silicon-on-insulator (SOI), or germanium-on-silicon structures compatible with standard CMOS processes, or as silicon-on-sapphire (SOS) structures.

Patellar Shape-Memory Fixator for the Treatment of Comminuted Fractures of the Inferior Pole of the Patella

NASA Astrophysics Data System (ADS)

Liu, Xin-Wei; Shang, Hui-Juan; Xu, Shuo-Gui; Wang, Zhi-Wei; Zhang, Chun-Cai; Fu, Qing-Ge

2011-07-01

Comminuted and displaced fractures of the inferior pole of the patella are not easy to reduce and it is difficult to fix the fragments soundly enough to allow early movement of the knee. The purpose of this study is to evaluate the clinical effectiveness of the internal fixation technique with Patellar Shape-Memory Fixator (PSMF) in acute comminuted fractures of the inferior pole of the patella. We retrospectively studied 25 patients with comminuted fractures of the inferior pole of the patella who were treated with PSMF and followed up for a mean period of 26 months (14 to 60). All the fractures healed at a mean of 6 weeks (5 to 7). The mean grading at the final follow-up was 29.5 points (27 to 30) using the Bostman score, with no observable restriction of movement. No breakage of the PSMF or infection occurred. No delayed union, nonunion, and infection were seen. This technique preserved the length of the patella, reduced the comminuted fragments of the inferior pole and avoided long-term immobilization of the knee.

History of Chandra X-Ray Observatory

NASA Image and Video Library

2000-12-18

This Chandra image of Jupiter shows concentrations of aurora x-rays near the north and south poles due to a single `hot spot' that pulsates with a period of 45 minutes, similar to high-latitude radio pulsation previously detected by NASA's Galileo and Cassini spacecraft. Previous x-ray detections of Jupiter have been made with other x-ray telescopes, but did not reveal that the sources of the x-rays, energetic oxygen and sulfur ions, would be located so near the poles. Previous theories held that ions were mostly coming from Jupiter's moon, lo. Chandra's ability to pinpoint the source of the x-rays discards this theory since ions coming from near lo's orbit carnot reach the observed high latitudes. One possibility is that particles flowing out from the Sun are captured in the outer regions of Jupiter's magnetic field, then accelerated and directed toward its magnetic pole. Once captured, the ions would bounce back and forth in the magnetic field from Jupiter's north pole to the south pole in an oscillating motion that could explain the pulsation.

Growth of Ponderosa pine poles thinned to different stocking levels in central Oregon.

Treesearch

James W. Barrett

1983-01-01

This paper presents 15-year results of one installation of a west-wide study of growing-stock levels in even-aged ponderosa pine. Growth was related to growing-stock level in a 65-year-old pole stand on an above average site. Periodic growth is presented for 10 years after the initial thinning and for 5 years after a second thinning to six assigned growing-stock levels...

29 CFR 1926.953 - Material handling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Material handling. (a) Unloading. Prior to unloading steel, poles, cross arms and similar material, the... stored in temporary containers other than those required in § 1926.152, such as pillow tanks. (f) Framing. During framing operations, employees shall not work under a pole or a structure suspended by a crane, A...

29 CFR 1926.953 - Material handling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Material handling. (a) Unloading. Prior to unloading steel, poles, cross arms and similar material, the... stored in temporary containers other than those required in § 1926.152, such as pillow tanks. (f) Framing. During framing operations, employees shall not work under a pole or a structure suspended by a crane, A...

Investigation of anchor nut loosening in high-mast light poles using field monitoring and finite element analysis.

DOT National Transportation Integrated Search

2014-09-01

High mast lighting poles (HMLPs) are cost effective structures for lighting highways and intersections. They are 100 to 250 feet (30m to 76m) tall, and can hold a variety of lamp configurations. They are : commonly used at highway interchanges becaus...

Saturn's Aurora Observed by Cassini Camera in Visible Wavelengths

NASA Astrophysics Data System (ADS)

Dyudina, U.; Ingersoll, A. P.; Ewald, S.; Wellington, D. F.

2014-12-01

Cassini camera's movies in 2009-2013 show Saturn's aurora in both the northern and southern hemispheres. The color of the aurora changes from pink at a few hundreds of km above the cloud tops to purple at 1000-1500 km above the cloud tops. The spectrum observed in 9 lters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with the laboratory simulated auroras [1]. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs, sometimes a spiral around the pole, and sometimes double arcs at 70-75 both north and south latitude. 10,000-km-scale longitudinal brightness structures can persist for more than 100 hours. This structures rotate together with Saturn. Besides the steady structure, the auroras brighten suddenly on the timescales of few minutes. 1000-km-scale disturbances may move faster or lag behind Saturn's rotation on timescales of tens of minutes. The persistence of the longitudinal structure of the aurora in two long observations in 2009 and 2012 allowed us to estimate its period of rotation of 10.65±0.15 h for 2009 and 10.8±0.1 h for 2012. The 2009 north aurora period is close to the north branch of Saturn Kilometric Radiation (SKR) detected at that time. The 2012 south aurora period is longer than the SKR periods detected at the time. These periods are also close to the rotation period of the lightning storms on Saturn. We discuss those periodicities and their relevance to Saturn's internal rotation. [1] Aguilar, A. et al. The Electron-Excited Mid-Ultraviolet to Near-Infrared Spectrum of H2:Cross Sections and Transition Probabilities. Astrophys. J. Supp. Ser. 177, 388-407 (2008).

Evaluation of domain randomness in periodically poled lithium niobate by diffraction noise measurement.

PubMed

Dwivedi, Prashant Povel; Choi, Hee Joo; Kim, Byoung Joo; Cha, Myoungsik

2013-12-16

Random duty-cycle errors (RDE) in ferroelectric quasi-phase-matching (QPM) devices not only affect the frequency conversion efficiency, but also generate non-phase-matched parasitic noise that can be detrimental to some applications. We demonstrate an accurate but simple method for measuring the RDE in periodically poled lithium niobate. Due to the equivalence between the undepleted harmonic generation spectrum and the diffraction pattern from the QPM grating, we employed linear diffraction measurement which is much simpler than tunable harmonic generation experiments [J. S. Pelc, et al., Opt. Lett.36, 864-866 (2011)]. As a result, we could relate the RDE for the QPM device to the relative noise intensity between the diffraction orders.

Narrowband, tunable, 2 µm optical parametric master-oscillator power amplifier with large-aperture periodically poled Rb:KTP

NASA Astrophysics Data System (ADS)

Coetzee, R. S.; Zheng, X.; Fregnani, L.; Laurell, F.; Pasiskevicius, V.

2018-06-01

A high-energy, ns, narrow-linewidth optical parametric oscillator and amplifier system based on large-aperture periodically poled Rb:KTP is presented. The 2 µm seed source is a singly resonant OPO locked with a transversely chirped volume Bragg grating, allowing a wavelength tuning of 21 nm and output linewidth of 0.56 nm. A maximum output energy of 52 mJ and conversion efficiency of 36% was obtained from the amplifier for a pump energy of 140 mJ. The high-energy and the robust and narrow dual-wavelength spectra obtained make this system an ideal pump source for difference frequency generation-based THz generation schemes.

Tunable and highly reproducible surface-enhanced Raman scattering substrates made from large-scale nanoparticle arrays based on periodically poled LiNbO3 templates

NASA Astrophysics Data System (ADS)

Liu, Xiaoyan; Kitamura, Kenji; Yu, Qiuming; Xu, Jiajie; Osada, Minoru; Takahiro, Nagata; Li, Jiangyu; Cao, Guozhong

2013-10-01

This work describes novel surface-enhanced Raman scattering (SERS) substrates based on ferroelectric periodically poled LiNbO3 templates. The templates comprise silver nanoparticles (AgNPs), the size and position of which are tailored by ferroelectric lithography. The substrate has uniform and large sampling areas that show SERS effective with excellent signal reproducibility, for which the fabrication protocol is advantageous in its simplicity. We demonstrate ferroelectric-based SERS substrates with particle sizes ranging from 30 to 70 nm and present tunable SERS effect from Raman active 4-mercaptopyridine molecules attached to AgNPs when excited by a laser source at 514 nm.

Large actuation strain over 0.3% in periodically orthogonal poled BaTiO3 ceramics and multilayer actuators via reversible domain switching

NASA Astrophysics Data System (ADS)

Wang, Qiangzhong; Li, Faxin

2018-06-01

Lead titanate zirconate (PZT) ceramics based piezoelectric actuators always suffer from small output strains (typically 0.1%–0.15%) and have recently been criticized for the toxicity problem of the high-concentration lead. In our recent work (Li et al 2017 J. Appl. Phys. 122 074103), we realized large local actuation strain nearly 0.6% in a periodically orthogonal poled (POP) PZT ceramics via reversible domain switching. In this work, we applied the POP method to barium titanate (BT) ceramics and proposed a specially designed multilayer actuator which can output large uniform strain. The simple tetragonal structure of BT ceramics makes it easier to understand the mechanism of reversible domain switching in POP ceramics and its lead-free characteristic is more promising. Firstly, a POP BT ceramic piece was fabricated and the actuation testing results show that local large actuation strain of 0.36% can be obtained under a field of 2 kV mm‑1 at 0.1 Hz. However, the actuation strain is non-uniform along the period direction, varying from 0.22% to 0.36%. Then, to output uniform large strain, a four-layer actuator based on the POP BT ceramics was designed and fabricated in which only the in-plane poled regions of the adjacent layers were bonded. Results show that the output strain turns to be uniform in this way, which is 0.34% under 2 kV mm‑1, resulting in a very high large-signal (=S max/E max) of 1700 pm V‑1. The large actuation strain is very stable and keeps unchanged after 20k cycles of operation. It drops quickly with the increasing frequency and is stabilized at 0.18% above 1.0 Hz. Finally, bipolar field testing was conducted on the POP BT based actuator. Results show that the actuator shows electrostriction-like symmetric bipolar actuation behavior with the repeatable actuation strain of 0.3% under 2 kV mm‑1. This work may provide a feasible solution to low frequency, large-strain lead-free piezoelectric actuation.

The Effect of Poling on the Properties of 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 Ceramics

NASA Astrophysics Data System (ADS)

Uršič, Hana; Tellier, Jenny; Hrovat, Marko; Holc, Janez; Drnovšek, Silvo; Bobnar, Vid; Alguero, Miguel; Kosec, Marija

2011-03-01

The effects of the poling field on the structural and electrical properties of 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (0.65PMN-0.35PT) ceramics were investigated. The highest piezoelectric coefficient d33, coupling coefficients kp, kt, and mechanical quality factor Qm were achieved for ceramics poled at electric fields between 2 and 3.5 kV/mm, whereas the d33, kp, kt, and Qm of ceramics poled at higher electric fields, i.e., 4 and 4.5 kV/mm, were lower. The non-poled ceramics contained 86% of the monoclinic phase with the space group Pm and 14% of the tetragonal phase with the space group P4mm. However, the ceramics poled at 2.5 kV/mm contained 99% of the monoclinic phase and the rest is the tetragonal phase. The results show that the ratio of the monoclinic to the tetragonal phases can be changed by the application of a poling electric field and that the extent of this change is dependent on the field strength.

SFG synthesis of general high-order all-pass and all-pole current transfer functions using CFTAs.

PubMed

Tangsrirat, Worapong

2014-01-01

An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the g m-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory.

SFG Synthesis of General High-Order All-Pass and All-Pole Current Transfer Functions Using CFTAs

PubMed Central

Tangsrirat, Worapong

2014-01-01

An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the g m-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory. PMID:24688375

Development of Superconducting Insertion Device Magnets at NSRRC

NASA Astrophysics Data System (ADS)

Hwang, C. S.; Chang, C. H.; Chen, H. H.; Jan, J. C.; Lin, F. Y.; Fan, T. C.; Chen, J.; Hsu, S. N.; Hsu, K. T.; Huang, M. H.; Chang, H. P.; Hsiung, G. Y.; Chien, Y. C.; Chen, J. R.; Kuo, C. C.; Chen, C. T.

2007-01-01

A superconducting wavelength shifter (SWLS) with a magnetic field of 6.5 T in cryogen-free operation provides X-rays for high-resolution X-ray microscopy, EXAFS, and medical imaging beamlines. A 32-pole superconducting wiggler (SW) with a period of 6.1 cm and a magnetic field of 3.2 T in a liquid helium bath provides for three dedicated protein crystallography beamlines. Additionally, three 16-pole in-achromatic superconducting wigglers (IASW) with a period of 6.1 cm and a field strength of 3.1 T were constructed in-house and installed between the first and second bending magnets of a TBA arc section. Development of a prototype superconducting undulator (SU15) with a period of 15 mm and a field strength of 1.4 T is currently underway at National Synchrotron Radiation Research Center (MSRRC).

Asteroid (367943) 2012 DA14 Flyby Spin State Analysis

NASA Astrophysics Data System (ADS)

Benson, Conor; Scheeres, Daniel J.; Moskovitz, Nicholas

2017-10-01

On February 15, 2013 asteroid 2012 DA14 experienced an extremely close Earth encounter, passing within 27700 km altitude. This flyby gave observers the chance to directly detect flyby-induced changes to the asteroid’s spin state and physical properties. The strongest shape and spin state constraints were provided by Goldstone delay-Doppler radar and visible-wavelength photometry taken after closest approach. These data indicated a roughly 40 m x 20 m object in non-principal axis rotation. NPA states are described by two fundamental periods. Pφ is the average precession period of the long/short axis about the angular momentum vector and Pψ is the rotation period about the long/short axis.WindowCLEAN (Belton & Gandhi 1988) power spectrum analysis of the post flyby light curve showed three prominent frequencies, two of which were 1:2 multiples of each other. Mueller et al. (2002) suggest peaks with this relationship are 1/Pφ and 2/Pφ, implying that Pφ = 6.35 hr. Likely values for Pψ were then 8.72, 13.95, or 23.39 hr. These Pφ,Pψ pairs yielded six candidate spin states in total, one LAM and one SAM per pair.Second to fourth order, two-dimensional Fourier series fits to the light curve were best for periods of 6.359 and 8.724 hr. The two other candidate pairs were also in the top ten fits. Inertia constraints of a roughly 2:1 uniform density ellipsoid eliminated two of the three SAM states. Using JPL Horizons ephemerides and Lambertian ellipsoids, simulated light curves were generated. The simulated and observed power spectra were then compared for all angular momentum poles and reasonable ellipsoid elongations. Only the Pφ = 6.359 hr and Pψ = 8.724 hr LAM state produced light curves consistent with the observed frequency structure. All other states were clearly incompatible. With two well-fitting poles found, phasing the initial attitude and angular velocity yielded plausible matches to the observed light curve. Neglecting gravitational torques, neither pole agreed with the observed pre-flyby light curve, suggesting that the asteroid’s spin state changed during the encounter, consistent with numerical simulation predictions. The consistency between the pre-flyby observations and simulated states will be discussed.

The stability of coupled renewal-differential equations with econometric applications

NASA Technical Reports Server (NTRS)

Rhoten, R. P.; Aggarwal, J. K.

1969-01-01

Concepts and results are presented in the fields of mathematical modeling, economics, and stability analysis. A coupled renewal-differential equation structure is presented as a modeling form for systems possessing hereditary characteristics, and this structure is applied to a model of the Austrian theory of business cycles. For realistic conditions, the system is shown to have an infinite number of poles, and conditions are presented which are both necessary and sufficient for all poles to lie strictly in the left half plane.

Model reduction and frequency residuals for a robust estimation of nonlinearities in subspace identification

NASA Astrophysics Data System (ADS)

De Filippis, G.; Noël, J. P.; Kerschen, G.; Soria, L.; Stephan, C.

2017-09-01

The introduction of the frequency-domain nonlinear subspace identification (FNSI) method in 2013 constitutes one in a series of recent attempts toward developing a realistic, first-generation framework applicable to complex structures. If this method showed promising capabilities when applied to academic structures, it is still confronted with a number of limitations which needs to be addressed. In particular, the removal of nonphysical poles in the identified nonlinear models is a distinct challenge. In the present paper, it is proposed as a first contribution to operate directly on the identified state-space matrices to carry out spurious pole removal. A modal-space decomposition of the state and output matrices is examined to discriminate genuine from numerical poles, prior to estimating the extended input and feedthrough matrices. The final state-space model thus contains physical information only and naturally leads to nonlinear coefficients free of spurious variations. Besides spurious variations due to nonphysical poles, vibration modes lying outside the frequency band of interest may also produce drifts of the nonlinear coefficients. The second contribution of the paper is to include residual terms, accounting for the existence of these modes. The proposed improved FNSI methodology is validated numerically and experimentally using a full-scale structure, the Morane-Saulnier Paris aircraft.

A vanadium-doped ZnO nanosheets-polymer composite for flexible piezoelectric nanogenerators

NASA Astrophysics Data System (ADS)

Shin, Sung-Ho; Kwon, Yang Hyeog; Lee, Min Hyung; Jung, Joo-Yun; Seol, Jae Hun; Nah, Junghyo

2016-01-01

We report high performance flexible piezoelectric nanogenerators (PENGs) by employing vanadium (V)-doped ZnO nanosheets (NSs) and the polydimethylsiloxane (PDMS) composite structure. The V-doped ZnO NSs were synthesized to overcome the inherently low piezoelectric properties of intrinsic ZnO. Ferroelectric phase transition induced in the V-doped ZnO NSs contributed to significantly improve the performance of the PENGs after the poling process. Consequently, the PENGs exhibited high output voltage and current up to ~32 V and ~6.2 μA, respectively, under the applied strain, which are sufficient to directly turn on a number of light emitting diodes (LEDs). The composite approach for PENG fabrication is scalable, robust, and reproducible during periodic bending/releasing over extended cycles. The approach introduced here extends the performance limits of ZnO-based PENGs and demonstrates their potential as energy harvesting devices.We report high performance flexible piezoelectric nanogenerators (PENGs) by employing vanadium (V)-doped ZnO nanosheets (NSs) and the polydimethylsiloxane (PDMS) composite structure. The V-doped ZnO NSs were synthesized to overcome the inherently low piezoelectric properties of intrinsic ZnO. Ferroelectric phase transition induced in the V-doped ZnO NSs contributed to significantly improve the performance of the PENGs after the poling process. Consequently, the PENGs exhibited high output voltage and current up to ~32 V and ~6.2 μA, respectively, under the applied strain, which are sufficient to directly turn on a number of light emitting diodes (LEDs). The composite approach for PENG fabrication is scalable, robust, and reproducible during periodic bending/releasing over extended cycles. The approach introduced here extends the performance limits of ZnO-based PENGs and demonstrates their potential as energy harvesting devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07185b

Cassini/CIRS Observations of Saturn’s Polar Vortices from Proximal Orbit Observations

NASA Astrophysics Data System (ADS)

Achterberg, Richard; Bjoraker, Gordon L.; Hesman, Brigette E.; Flasar, F. Michael

2017-10-01

The proximal orbit phase of the Cassini mission, with periapses inside the inner edge of the rings, has allowed observations of Saturn’s atmosphere with unprecedented spatial resolution. During the periapse periods on 26 April and 29 June 2017, the Composite Infrared Spectrometer (CIRS) performed scans over both the north and south poles with a spatial resolution better than 0.2° of latitude, over a factor of 4 better resolution than previous observations. A further observation of the south pole is planned on 20 Aug 2017.Previous thermal infrared observations of Saturn’s poles [1,2] showed a compact hot spot in the upper troposphere at each pole, roughly coincident with the hurricane-like polar vortex seen in visible imaging [3]. Preliminary results from the proximal orbit scans of the north pole, near summer solstice, show that in the upper troposphere, the meridional temperature gradient increases sharply at about 89°N, with the temperature increasing by ~5K between 89°N and the pole, with the temperature gradient persisting all the way to the pole within the spatial resolution of the observation. In the northern stratosphere, the polar hot spot is broader than in the troposphere, extending to ~86°N at 4 mbar, and disappearing into the general meridional gradient at 1 mbar.[1] G. S. Orton and P. A. Yanamadra-Fisher, Science 307, 696[2] L. N. Fletcher et al., Science, 319, 79[3] U. A. Dyudina et al., Icarus, 202, 240.

Saturn's visible aurora

NASA Astrophysics Data System (ADS)

Dyudina, U.; Ingersoll, A. P.; Ewald, S.; Porco, C. C.

2013-09-01

Cassini camera's movies show Saturn's aurora in both the northern and southern hemispheres. The color of the aurora changes from pink at a few hundreds of km above the cloud tops to purple at 1000-1500 km above the cloud tops. The spectrum observed in 9 filters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with the laboratory simulated auroras by [1]. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs, sometimes a spiral around the pole, and sometimes double arcs at 70-75° both north and south latitude. 10,000-km-scale longitudinal brightness structure can persist for ∼˜3 days. This structure rotates together with Saturn. Besides the steady structure, the auroras brighten suddenly on the timescales of few minutes. 1000-km-scale disturbances may move faster or lag behind Saturn's rotation on timescales of tens of minutes. The auroral curtains can extend more than 1200 km from their base to their top. The stability of the longitudinal structure of the aurora in 2009 allowed us to estimate its period of rotation of 10.65 ± 0.05 h. This is consistent to the Saturn Kilometric Radiation (SKR) period detected by Cassini in 2009. These periods are also close to the rotation period of the lightning storms on Saturn. We discuss those periodicities and their relevance to Saturn's rotation. In April-May 2013 a multi-instrument campaign using Cassini and Earth-based data was monitoring Saturn's aurora. We will discuss the results of this campaign.

Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schroedinger Basin

NASA Technical Reports Server (NTRS)

Mest, S. C.; Berman, D. C.; Petro, N. E.

2009-01-01

In this study we use recent images and topographic data to map the geology and geomorphology of the lunar South Pole quadrangle (LQ-30) at 1:2.5M scale [1-4] in accordance with the Lunar Geologic Mapping Program. Mapping of LQ-30 began during Mest's postdoctoral appointment and has continued under the PG&G Program, from which funding became available in February 2009. Preliminary map-ping and analyses have been done using base materials compiled by Mest, but properly mosaicked and spatially registered base materials are being compiled by the USGS and should be received by the end of June 2009. The overall objective of this research is to constrain the geologic evolution of the lunar South Pole (LQ-30: 60deg -90deg S, 0deg - +/-180deg ) with specific emphasis on evaluation of a) the regional effects of basin formation on the structure and composition of the crust and b) the spatial distribution of ejecta, in particular resulting from formation of the South Pole-Aitken (SPA) basin and other large basins. Key scientific objectives include: 1) Constraining the geologic history of the lunar South Pole and examining the spatial and temporal variability of geologic processes within the map area. 2) Constraining the vertical and lateral structure of the lunar regolith and crust, assessing the distribution of impact-generated materials, and determining the timing and effects of major basin-forming impacts on crustal structure and stratigraphy in the map area. And 3) assessing the distribution of resources (e.g., H, Fe, Th) and their relationships with surface materials.

A precisely dated Proterozoic palaeomagnetic pole from the North China craton, and its relevance to palaeocontinental reconstruction

NASA Astrophysics Data System (ADS)

Halls, Henry C.; Li, Jianghai; Davis, Don; Hou, Guiting; Zhang, Baoxing; Qian, Xianglin

2000-10-01

A palaeomagnetic pole position, derived from a precisely dated primary remanence, with minimal uncertainties due to secular variation and structural correction, has been obtained for China's largest dyke swarm, which trends for about 1000km in a NNW direction across the North China craton. Positive palaeomagnetic contact tests on two dykes signify that the remanent magnetization is primary and formed during initial cooling of the intrusions. The age of one of these dykes, based on U-Pb dating of primary zircon, is 1769.1+/-2.5Ma. The mean palaeomagnetic direction for 19 dykes, after structural correction, is D=36°, I=-5°, k=63, α95=4°, yielding a palaeomagnetic pole at Plat=36°N, Plong=247°E, dp=2°, dm=4° and a palaeolatitude of 2.6°S. Comparison of this pole position with others of similar age from the Canadian Shield allows a continental reconstruction that is compatible with a more or less unchanged configuration of Laurentia, Siberia and the North China craton since about 1800Ma

Rock magnetic and paleomagnetic study of the Keurusselkä impact structure, central Finland

NASA Astrophysics Data System (ADS)

Raiskila, Selen; Salminen, Johanna; Elbra, Tiiu; Pesonen, Lauri J.

2011-11-01

There are 31 proven impact structures in Fennoscandia—one of the most densely crater-populated areas of the Earth. The recently discovered Keurusselkä impact structure (62°08' N, 24°37' E) is located within the Central Finland Granitoid Complex, which formed 1890-1860 Ma ago during the Svecofennian orogeny. It is a deeply eroded complex crater that yields in situ shatter cones with evidence of shock metamorphism, e.g., planar deformation features in quartz. New petrophysical and rock magnetic results of shocked and unshocked target rocks of various lithologies combined with paleomagnetic studies are presented. The suggested central uplift with shatter cones is characterized by increased magnetization and susceptibility. The presence of magnetite and pyrrhotite was observed as carriers for the remanent magnetization. Four different remanent magnetization directions were isolated: (1) a characteristic Svecofennian target rock component A with a mean direction of D = 334.8°, I = 45.6°, α95 = 14.9° yielding a pole (Plat = 51.1°, Plon = 241.9°, A95 = 15.1°), (2) component B, D = 42.4°, I = 64.1°, α95 = 8.4° yielding a pole (Plat = 61.0°, Plon = 129.1°, A95 = 10.6°), (3) component C (D = 159.5°, I = 65.4°, α95 = 10.7°) yielding a pole (Plat = 21.0°, Plon = 39.3°, A95 = 15.6°), and (4) component E (D = 275.5°, I = 62.0°, α95 = 14.4°) yielding a pole (Plat = 39.7°, Plon = 314.3°, A95 = 19.7°). Components C and E are considered much younger, possibly Neoproterozoic overprints, compared with the components A and B. The pole of component B corresponds with the 1120 Ma pole of Salla diabase dyke and is in agreement with the 40Ar/39Ar age of 1140 Ma from a pseudotachylitic breccia vein in a central part of the structure. Therefore, component B could be related to the impact, and thus represent the impact age.

Sound transmission through a double panel structure periodically coupled with vibration insulators

NASA Astrophysics Data System (ADS)

Legault, Julien; Atalla, Noureddine

2010-07-01

In this paper, sound transmission through an aircraft sidewall representative double panel structure is investigated theoretically and parametric and validation studies are conducted. The studied configuration is composed of a trim panel (receiver side panel) attached to a ribbed skin panel (source side panel) with periodically spaced resilient mounts. The structure is considered infinite in order to use space harmonic expansion. The partition is also assumed planar for simplicity. The model allows for a 3D incident field and the panels can be metallic and/or composite. A four-pole formulation is employed for modeling of the mounts and the absorption provided by the fiberglass that fills the cavity between the leaves is addressed with an equivalent fluid model. The investigation of mount stiffness, damping and spacing show that properly designed mounts can increase the TL significantly (up to 20 dB of difference between rigid and resilient mounts). However, they can create undesirable resonances resulting from their interaction with the panels. The influence of cavity absorption is also studied and results illustrate the fact that it is not worth investing in a highly absorbent fiber if the structure-borne transmission path is not adequately insulated, and likewise that it is not worth investing in highly resilient mounts without sufficient cavity absorption. Moreover, the investigation of panel damping confirms that when structure-borne transmission is present, raising skin damping can increase the TL even below coincidence, but that on average, greater improvements are achieved by raising trim damping. Finally, comparison between the periodic model and finite element simulations for structure-borne transmission shows that the average level of transmitted energy is well reproduced with the periodic approach. However, the modes are only captured approximately due to the assumption of an infinite structure.

Study of the National Science Foundation's South Pole Station as an analogous data base for the logistical support of a Moon laboratory

NASA Technical Reports Server (NTRS)

Hickam, H. H., Jr.

1993-01-01

The day will come when the United States will want to return to the Earth's Moon. When that occurs, NASA may look to the Apollo program for technical and inspirational guidance. The Apollo program, however, was designed to be an end to itself--the landing of a man on the Moon and his return safely within the decade of the 1960's. When that was accomplished, the program folded because it was not self-sustaining. The next time we return to the Moon, we should base our planning on a program that is designed to be a sustained effort for an indefinite period. It is the thrust of this report that the South Pole Station of the National Science Foundation can be used to develop analogs for the construction, funding, and logistical support of a lunar base. Other analogs include transportation and national efforts versus international cooperation. A recommended lunar base using the South Pole Station as inspiration is provided, as well as details concerning economical construction of the base over a 22-year period.

Imaging Borrelly

USGS Publications Warehouse

Soderblom, L.A.; Boice, D.C.; Britt, D.T.; Brown, R.H.; Buratti, B.J.; Kirk, R.L.; Lee, M.; Nelson, R.M.; Oberst, J.; Sandel, B.R.; Stern, S.A.; Thomas, N.; Yelle, R.V.

2004-01-01

The nucleus, coma, and dust jets of short-period Comet 19P/Borrelly were imaged from the Deep Space 1 spacecraft during its close flyby in September 2001. A prominent jet dominated the near-nucleus coma and emanated roughly normal to the long axis of nucleus from a broad central cavity. We show it to have remained fixed in position for more than 34 hr, much longer than the 26-hr rotation period. This confirms earlier suggestions that it is co-aligned with the rotation axis. From a combination of fitting the nucleus light curve from approach images and the nucleus' orientation from stereo images at encounter, we conclude that the sense of rotation is right-handed around the main jet vector. The inferred rotation pole is approximately perpendicular to the long axis of the nucleus, consistent with a simple rotational state. Lacking an existing IAU comet-specific convention but applying a convention provisionally adopted for asteroids, we label this the north pole. This places the sub-solar latitude at ???60?? N at the time of the perihelion with the north pole in constant sunlight and thus receiving maximum average insolation. ?? 2003 Elsevier Inc. All rights reserved.

[Should morphology of the upper pole in renal duplication with preserved function and associated ureterocele be taken into account during treatment planning?].

PubMed

Materny, Jacek; Chojnacka, Hanna; Urasińska, Elzbieta; Gawrych, Elzbieta

2011-01-01

The aim of this study was to assess structural changes of the upper pole in renal duplication with coexisting ureterocele with regard to primary and/or secondary lesions. These changes might be of importance in treatment planning. The material of this study consisted of clinical documentation and results of histopathology of 23 upper poles removed due to renal duplication with coexisting ureterocele. The qualification criterion was preserved function of the upper pole seen with 99mTc-DTPA (99mTechnetium diethylenetriaminepentaacetic acid)/99mTc-DMSA (99mTechnetium dimercaptosuccinic acid). Resection of the upper pole was indicated in patients with recurrent urinary tract infections and/or persistent vesicoureteral reflux to the lower pole following endoscopic surgery of the ureterocele and/or low function of the upper pole. Morphological lesions were classified as primary (dysplasia) or secondary lesions. The patients were operated at the Department of Pediatric and Oncologic Surgery, PMU, in 1990-2008. The study group consisted of 17 girls and 6 boys aged from 4 months to 9 years (mean 40 months). Recurrent urinary tract infections noted in 16 (70%) children were the most frequent indication for surgery. The preoperative mean function of the renal poles assessed with DTPA/DMSA represented 6% of the differential renal function. Dysplasia was identified in eight resected renal poles (34%) with coexisting secondary lesions in three of them. Secondary lesions only were seen in 15 poles (66%). There was no correlation between age and incidence of dysplasia during follow-up (Pearson's correlation coefficient r = 0.031). Secondary lesions are a quite frequent finding in resected upper poles. As 66% of the renal poles studied with histopathology revealed secondary lesions only, we believe that renal sparing treatment is justified in cases of urinary duplication with coexisting ureterocele.

Condition Assessment of Foundation Piles and Utility Poles Based on Guided Wave Propagation Using a Network of Tactile Transducers and Support Vector Machines

PubMed Central

Yu, Yang; Niederleithinger, Ernst; Li, Jianchun; Wiggenhauser, Herbert

2017-01-01

This paper presents a novel non-destructive testing and health monitoring system using a network of tactile transducers and accelerometers for the condition assessment and damage classification of foundation piles and utility poles. While in traditional pile integrity testing an impact hammer with broadband frequency excitation is typically used, the proposed testing system utilizes an innovative excitation system based on a network of tactile transducers to induce controlled narrow-band frequency stress waves. Thereby, the simultaneous excitation of multiple stress wave types and modes is avoided (or at least reduced), and targeted wave forms can be generated. The new testing system enables the testing and monitoring of foundation piles and utility poles where the top is inaccessible, making the new testing system suitable, for example, for the condition assessment of pile structures with obstructed heads and of poles with live wires. For system validation, the new system was experimentally tested on nine timber and concrete poles that were inflicted with several types of damage. The tactile transducers were excited with continuous sine wave signals of 1 kHz frequency. Support vector machines were employed together with advanced signal processing algorithms to distinguish recorded stress wave signals from pole structures with different types of damage. The results show that using fast Fourier transform signals, combined with principal component analysis as the input feature vector for support vector machine (SVM) classifiers with different kernel functions, can achieve damage classification with accuracies of 92.5% ± 7.5%. PMID:29258274

Scavenging energy from human motion with tubular dielectric polymer

NASA Astrophysics Data System (ADS)

Jean-Mistral, Claire; Basrour, Skandar

2010-04-01

Scavenging energy from human motion is a challenge to supply low consumption systems for sport or medical applications. A promising solution is to use electroactive polymers and especially dielectric polymers to scavenge mechanical energy during walk. In this paper, we present a tubular dielectric generator which is the first step toward an integration of these structures into textiles. For a 10cm length and under a strain of 100%, the structure is able to scavenge 1.5μJ for a poling voltage of 200V and up to 40μJ for a poling voltage of 1000V. A 30cm length structure is finally compared to our previous planar structure, and the power management module for those structures is discussed.

Solar Open Flux Migration from Pole to Pole: Magnetic Field Reversal.

PubMed

Huang, G-H; Lin, C-H; Lee, L C

2017-08-25

Coronal holes are solar regions with low soft X-ray or low extreme ultraviolet intensities. The magnetic fields from coronal holes extend far away from the Sun, and thus they are identified as regions with open magnetic field lines. Coronal holes are concentrated in the polar regions during the sunspot minimum phase, and spread to lower latitude during the rising phase of solar activity. In this work, we identify coronal holes with outward and inward open magnetic fluxes being in the opposite poles during solar quiet period. We find that during the sunspot rising phase, the outward and inward open fluxes perform pole-to-pole trans-equatorial migrations in opposite directions. The migration of the open fluxes consists of three parts: open flux areas migrating across the equator, new open flux areas generated in the low latitude and migrating poleward, and new open flux areas locally generated in the polar region. All three components contribute to the reversal of magnetic polarity. The percentage of contribution from each component is different for different solar cycle. Our results also show that the sunspot number is positively correlated with the lower-latitude open magnetic flux area, but negatively correlated with the total open flux area.

Continuous-wave sodium D2 resonance radiation generated in single-pass sum-frequency generation with periodically poled lithium niobate.

PubMed

Yue, J; She, C-Y; Williams, B P; Vance, J D; Acott, P E; Kawahara, T D

2009-04-01

With two cw single-mode Nd:YAG lasers at 1064 and 1319 nm and a periodically poled lithium niobate crystal, 11 mW of 2 kHz/100 ms bandwidth single-mode tunable 589 nm cw radiation has been detected using single-pass sum-frequency generation. The demonstrated conversion efficiency is approximately 3.2%[W(-1) cm(-1)]. This compact solid-state light source has been used in a solid-state-dye laser hybrid sodium fluorescence lidar transmitter to measure temperatures and winds in the upper atmosphere (80-105 km); it is being implemented into the transmitter of a mobile all-solid-state sodium temperature and wind lidar under construction.

Manifestations of motions of the Earth's pole in the El Niño-Southern Oscillation rhythms

NASA Astrophysics Data System (ADS)

Serykh, I. V.; Sonechkin, D. M.

2017-02-01

We analyze autocorrelations and power spectra of the time series of monthly mean data characterizing sea surface temperature anomalies in the equatorial Pacific in the years 1920-2013 and show that the rhythms of El Niño-Southern Oscillation can be interpreted as the responses of the climate system to the external quasi-periodic forcing generated by the motions of the Earth's pole. We conclude that the ENSO phenomenon has no prediction limits.

Experimental evidence of interhemispheric transport from airborne carbon monoxide measurements

NASA Technical Reports Server (NTRS)

Newell, R. E.; Gauntner, D. J.

1979-01-01

During the period 28-30 October 1977, a Pan American 747-SP aircraft flew around the world with an automated instrument package that included measurements of atmospheric CO made every 4 sec. The flight path extended from San Francisco, over the North Pole to London, south to Capetown, over the South Pole to Auckland, and back to San Francisco. The data collected show large changes with longitude, which are interpreted as direct evidence of interhemispheric mixing. Possible sources for CO are discussed.

7 CFR 1728.97 - Incorporation by reference of electric standards and specifications.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Brackets (5-53) Bulletin 50-56 (T-3), RUS Specifications for Steel Plate Anchors for Transmission Lines (12-53) Bulletin 50-60 (T-9), RUS Specification—Single Pole Steel Structures, Complete with Arms (12-71... Pole Top Pins with 1″ Diameter Lead Threads (2-79) Bulletin 50-32 (D-4), RUS Specifications for Steel...

Saturn's aurora observed by Cassini camera in visible wavelengths

NASA Astrophysics Data System (ADS)

Dyudina, Ulyana; Porco, Carolyn; Ingersoll, Andrew; Ewald, Shawn; Wellington, Danika

Cassini camera's movies in 2009-2013 show Saturn's aurora in both the northern and southern hemispheres. The color of the aurora changes from pink at a few hundreds of km above the cloud tops to purple at 1000-1500 km above the cloud tops. The spectrum observed in 9 filters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with the laboratory simulated auroras [1]. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs, sometimes a spiral around the pole, and sometimes double arcs at 70-75(°) both north and south latitude. 10,000-km-scale longitudinal brightness structures can persist for more than 100 hours. This structures rotate together with Saturn. Besides the steady structure, the auroras brighten suddenly on the timescales of few minutes. 1000-km-scale disturbances may move faster or lag behind Saturn's rotation on timescales of tens of minutes. The persistence of the longitudinal structure of the aurora in two long observations in 2009 and 2012 allowed us to estimate its period of rotation of 10.65 ± 0.15 h for 2009 and 10.8± 0.1 h for 2012. The 2009 north aurora period is close to the north branch of Saturn Kilometric Radiation (SKR) detected at that time. The 2012 south aurora period is longer than any SKR periods detected at the time, but it is similar to the SKR period of the south branch of SKR periods in 2004-2008. These periods are also close to the rotation period of the lightning storms on Saturn. We discuss those periodicities and their relevance to Saturn's internal rotation. [1] Aguilar, A. et al. The Electron-Excited Mid-Ultraviolet to Near-Infrared Spectrum of H_2: Cross Sections and Transition Probabilities. Astrophys. J. Supp. Ser. 177, 388-407 (2008).

Performance Analysis of a Pole and Tree Trunk Detection Method for Mobile Laser Scanning Data

NASA Astrophysics Data System (ADS)

Lehtomäki, M.; Jaakkola, A.; Hyyppä, J.; Kukko, A.; Kaartinen, H.

2011-09-01

Dense point clouds can be collected efficiently from large areas using mobile laser scanning (MLS) technology. Accurate MLS data can be used for detailed 3D modelling of the road surface and objects around it. The 3D models can be utilised, for example, in street planning and maintenance and noise modelling. Utility poles, traffic signs, and lamp posts can be considered an important part of road infrastructure. Poles and trees stand out from the environment and should be included in realistic 3D models. Detection of narrow vertical objects, such as poles and tree trunks, from MLS data was studied. MLS produces huge amounts of data and, therefore, processing methods should be as automatic as possible and for the methods to be practical, the algorithms should run in an acceptable time. The automatic pole detection method tested in this study is based on first finding point clusters that are good candidates for poles and then separating poles and tree trunks from other clusters using features calculated from the clusters and by applying a mask that acts as a model of a pole. The method achieved detection rates of 77.7% and 69.7% in the field tests while 81.0% and 86.5% of the detected targets were correct. Pole-like targets that were surrounded by other objects, such as tree trunks that were inside branches, were the most difficult to detect. Most of the false detections came from wall structures, which could be corrected in further processing.

Development of a Multiple Input Integrated Pole-to-Pole Global CMORPH

NASA Astrophysics Data System (ADS)

Joyce, R.; Xie, P.

2013-12-01

A test system is being developed at NOAA Climate Prediction Center (CPC) to produce a passive microwave (PMW), IR-based, and model integrated high-resolution precipitation estimation on a 0.05olat/lon grid covering the entire globe from pole to pole. Experiments have been conducted for a summer Test Bed period using data for July and August of 2009. The pole-to-pole global CMORPH system is built upon the Kalman Filter based CMORPH algorithm of Joyce and Xie (2011). First, retrievals of instantaneous precipitation rates from PMW observations aboard nine low earth orbit (LEO) satellites are decoded and pole-to-pole mapped onto a 0.05olat/lon grid over the globe. Also precipitation estimates from LEO AVHRR retrievals are derived using a PDF matching of LEO IR with calibrated microwave combined (MWCOMB) precipitation retrievals. The motion vectors for the precipitating cloud systems are defined using information from both satellite IR observations and precipitation fields generated by the NCEP Climate Forecast System Reanalysis (CFSR). To this end, motion vectors are first computed for the CFSR hourly precipitation fields through cross-correlation analysis of consecutive hourly precipitation fields on the global T382 (~35 km) grid. In a similar manner, separate processing is also performed on satellite IR-based precipitation estimates to derive motion vectors from observations. A blended analysis of precipitating cloud motion vectors is then constructed through the combination of CFSR and satellite-derived vectors utilizing a two-dimensional optimal interpolation (2D-OI) method, in which CFSR-derived motion vectors are used as the first guess and subsequently satellite derived vectors modify the first guess. Weights used to generate the combinations are defined under the OI framework as a function of error statistics for the CFSR and satellite IR based motion vectors. The screened and calibrated PMW and AVHRR derived precipitation estimates are then separately spatially propagated forward and backward in time, using precipitating cloud motion vectors, from their observation time to the next PMW observation. The PMW estimates propagated in both the forward and backward directions are then combined with propagated IR-based precipitation estimates under the Kalman Filter framework, with weights defined based on previously determined error statistics dependent on latitude, season, surface type, and temporal distance from observation time. Performance of the pole-to-pole global CMORPH and its key components, including combined PMW (MWCOMB), IR-based, and model precipitation, as well as model-derived, IR-based, and blended precipitation motion vectors, will be examined against NSSL Q2 radar observed precipitation estimates over CONUS, Finland FMI radar precipitation, and a daily gauge-based analysis including daily Canadian surface reports over global land. Also an initial investigation will be performed over a January - February 2010 winter Test Bed period. Detailed results will be reported at the Fall 2013 AGU Meeting.

On the origin of the low-temperature band in depolarization current spectra of poled multicomponent silicate glasses

NASA Astrophysics Data System (ADS)

Brunkov, P. N.; Kaasik, V. P.; Lipovskii, A. A.; Tagantsev, D. K.

2018-04-01

Thermally stimulated depolarization current spectra of poled silicate multicomponent glasses in the vicinity of room temperature (220-320 K) have been recorded and two bands, typical for such glasses, have been observed. It was shown that the high-temperature band (at about 290 K) is related to the relaxation of poled glass structure in the bulk, while the low-temperature band (at about 230-270 K) should be attributed to the surface phenomenon—absorption/desorption of positive species of ambient atmosphere, supposedly, water cluster ions H+(H2O)n.

Second-order non-linear optical studies on CdS microcrystallite-doped alkali borosilicate glasses

NASA Astrophysics Data System (ADS)

Liu, Hao; Liu, Qiming; Wang, Mingliang; Zhao, Xiujian

2007-05-01

CdS microcrystal-doped alkali borosilicate glasses were prepared by conventional fusion and heat-treatment method. Utilizing Maker fringe method, second-harmonic generation (SHG) was both observed from CdS-doped glasses before and after certain thermal/electrical poling. While because the direction of polarization axes of CdS crystals formed in the samples is random or insufficient interferences of generated SH waves occur, the fringe patterns obtained in samples without poling treatments showed no fine structures. For the poled samples, larger SH intensity has been obtained than that of the samples without any poling treatments. It was considered that the increase of an amount of hexagonal CdS in the anode surface layer caused by the applied dc field increased the SH intensity. The second-order non-linearity χ(2) was estimated to be 1.23 pm/V for the sample poled with 2.5 kV at 360 °C for 30 min.

Minimax rational approximation of the Fermi-Dirac distribution.

PubMed

Moussa, Jonathan E

2016-10-28

Accurate rational approximations of the Fermi-Dirac distribution are a useful component in many numerical algorithms for electronic structure calculations. The best known approximations use O(log(βΔ)log(ϵ -1 )) poles to achieve an error tolerance ϵ at temperature β -1 over an energy interval Δ. We apply minimax approximation to reduce the number of poles by a factor of four and replace Δ with Δ occ , the occupied energy interval. This is particularly beneficial when Δ ≫ Δ occ , such as in electronic structure calculations that use a large basis set.

Minimax rational approximation of the Fermi-Dirac distribution

NASA Astrophysics Data System (ADS)

Moussa, Jonathan E.

2016-10-01

Accurate rational approximations of the Fermi-Dirac distribution are a useful component in many numerical algorithms for electronic structure calculations. The best known approximations use O(log(βΔ)log(ɛ-1)) poles to achieve an error tolerance ɛ at temperature β-1 over an energy interval Δ. We apply minimax approximation to reduce the number of poles by a factor of four and replace Δ with Δocc, the occupied energy interval. This is particularly beneficial when Δ ≫ Δocc, such as in electronic structure calculations that use a large basis set.

Residual strength and stiffness of lumber from decommissioned chromated copper arsenate-treated southern pine utility poles

Treesearch

Cheng Piao; Leslie Groom

2010-01-01

The reusability of decommissioned treated wood is primarily dependent on the residual strength of the wood after service. Determining the residual strength can provide useful information for structural design and reuse of the decommissioned treated wood. This study evaluated the residual strength of decommissioned chromated copper arsenate–treated utility pole wood....

SOUTH ELEVATION OF BATTERY COMMAND CENTER WITH GRADUATED MEASURING POLE. ...

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

SOUTH ELEVATION OF BATTERY COMMAND CENTER WITH GRADUATED MEASURING POLE. THE ENTRY STAIRWAY IS IN THE FOREGROUND. THE ABOVE-GROUND SECTION OF THE STRUCTURE IS ON THE RIGHT, UNDERGROUND PORTION ON THE LEFT. VIEW FACING NORTH - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

Building on IPY Data, Collaborations and Infrastructure to Understand the Changing Poles (Invited)

NASA Astrophysics Data System (ADS)

Bell, R. E.; Krupnik, I.; Hik, D.; Alverson, K. D.; Drinkwater, M. R.

2010-12-01

In contrast to previous IPY programs that were driven by a central organizing group, the 2007-9 IPY emerged from more than 1000 ideas provided by the global science community. This global IPY planning process produced six major themes that framed the IPY programs. Three themes focused on change at the poles, one focused on probing the frontiers of the polar science, one targeted on using the polar regions as vantage points to look beyond into space and a sixth theme targeted integrated studies of polar cultural, historical and social processes. The results of the IPY 2007-9 are just beginning to emerge. Benchmark data sets were acquired such as coordinated imaging of the poles from space, systematic ocean measurements and a census of marine life. IPY programs have documented how ongoing polar change from permafrost to ecosystems varies regionally depending on local conditions. Analysis of past change in ecosystems, sediment cores and numeric models indicate that during periods with elevated temperatures and atmospheric CO2, the West Antarctic ice sheet can collapse repeatedly. Studies of the polar oceans have confirmed a strong connection between the mid-latitudes and polar processes. The efforts to explore the poles have revealed explosive volcanism beneath the Arctic Ocean, strong genetic similarities between microbes at the two poles and dynamic processes at the base of the East Antarctic ice sheet. IPY programs looking beyond the poles imaged new galaxies and identified new linkages between solar output and weather. The early insights from IPY 2007-9 are remarkable. Building on these will be a challenge for the science community and science agencies over the next decade. The IPY data must be archived and made available to the broad science community to ensure it is preserved as a vital benchmark. The collaborations between scientists, agencies, Arctic residents and institutions initiated by the IPY structure must be fostered and continued. Successful scientific programs in the poles continue to necessitate shared resources, ideas and infrastructure. Goals for the post IPY 2007-9 polar science should include: (1) securing a robust, internationally-coordinated polar-observing infrastructure by sustaining existing IPY elements, complemented by critical new observations to fill identified gaps; (2) building complete ice, ocean, terrestrial and atmospheric data sets to facilitate accurate models of earth systems that will enable prediction and adaptation to future change; (3) recognition that fundamental exploratory science is necessary to ensure our ideas are not too narrow and entrenched; (4) interdisciplinary work must be encouraged to understand the complexity of coupled systems; (5) building on the IPY education and outreach efforts to ensure a vibrant new cohort of polar scientists ready to address polar change and its global ramifications.

Structural analysis of fertilization in the fish Brycon orbignyanus.

PubMed

Ganeco, Luciana Nakaghi; Franceschini-Vicentini, Irene Bastos; Nakaghi, Laura Satiko Okada

2009-05-01

In the present work, we analyzed the structure of oocytes and fertilized eggs of the piracanjuba fish (Brycon orbignyanus) under light and scanning electron microscopy. After inducing spawning, samples were collected at the moment of oocyte extrusion, when oocytes and semen were mixed (time 0), as well as at 10, 20 and 30 s after mixing, every minute up to 10 min, and then at 15 and 20 min. The oocytes are spherical, translucent and greenish with a mean diameter of 1.3 +/- 0.11 mm. During the extrusion, cytoplasmic movement was observed in eggs towards the micropyle, characterizing the animal pole. At the moment of fertilization, the cortical cytoplasm showed a higher concentration of cortical alveoli at the animal pole than at the vegetal pole. The cortical alveoli breakdown promoted the elevation of the chorion with a consequent increase in egg diameter (1.95 +/- 0.08 mm). The penetration of the spermatozoon promotes the formation of a fertilization cone of spherical external structure, which obstructs the opening of the micropyle. This structure acts as a main mechanism to avoid polyspermy, intercepting the access of supernumerary spermatozoa. Such studies about the reproductive biology of fish are important to species survival and conservation programmes.

Dow and Mary Davidson residence - A residence in a hot humid climate with major living spaces in rooms without walls

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

Holder, L.M. III; Holder, L.M. IV

Dow Davidson works out of his home while his wife, Mary, home schools their three children. The entire family uses the house full time throughout the year. Dow and Mary Davidson stressed the importance of a home with minimal site disruption while providing for as many human needs as practical. Specific requirements were for harmony with the natural climate and adjacent bird sanctuary. The clients had a strong preference for a pole structural system reflecting buildings they were familiar with in Hawaii. The house was designed as a pole structure utilizing passive solar heating, natural ventilation, night flushing, daylighting, rainwatermore » harvesting, and an outdoor and indoor living area without walled separation from the climate. This type of open indoor/outdoor living is an extension of the Hawaiian experience. Use of the pole structure system provided compatibility between the residence and the neighboring bird habitat. The completed house easily blended with the surrounding vegetation due to the extensive use of natural materials. Exterior walks and drives, made from caliche and mulch (harvested from cedar cut on-site), helped further balance the structure with the terrain and vegetation.« less

Saturn's Visible Aurora

NASA Astrophysics Data System (ADS)

Dyudina, U.; Ingersoll, A. P.; Wellington, D. F.; Ewald, S.; Porco, C.

2013-12-01

Cassini camera's movies show Saturn's aurora in both the northern and southern hemispheres. The color of the aurora changes from pink at a few hundreds of km above the cloud tops to purple at 1000-1500 km above the cloud tops. The spectrum observed in 9 filters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with the laboratory simulated auroras by [1]. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs, sometimes a spiral around the pole, and sometimes double arcs. Auroras are observed at 70-75 degrees both north and south latitude. 10,000-km-scale longitudinal brightness structure can persist for more than 3 days. This structure rotates together with Saturn. Besides the steady structure, the auroras brighten suddenly on the timescales of few minutes. 1000-km-scale disturbances may move faster or lag behind Saturn's rotation on timescales of tens of minutes. The stability of the longitudinal structure of the aurora in 2009 allowed us to estimate its period of rotation of about 10.65 h. This is consistent with Voyager System III rotation and with the Saturn Kilometric Radiation (SKR) period detected by Cassini at the time of aurora observations. These periods are also close to the rotation period of the lightning storms on Saturn. We discuss those periodicities and their relevance to Saturn's rotation. In April-May 2013 a multi-instrument campaign using Cassini and Earth-based data was monitoring Saturn's aurora. We will discuss the results of this campaign. [1] Aguilar, A. et al. The Electron-Excited Mid-Ultraviolet to Near-Infrared Spectrum of H2: Cross Sections and Transition Probabilities. Astrophys. J. Supp. Ser. 177, 388-407 (2008).

Surface-micromachined magnetic undulator with period length between 10μm and 1 mm for advanced light sources

NASA Astrophysics Data System (ADS)

Harrison, Jere; Joshi, Abhijeet; Lake, Jonathan; Candler, Rob; Musumeci, Pietro

2012-07-01

A technological gap exists between the μm-scale wiggling periods achieved using electromagnetic waves of high intensity laser pulses and the mm scale of permanent-magnet and superconducting undulators. In the sub-mm range, surface-micromachined soft-magnetic micro-electro-mechanical system inductors with integrated solenoidal coils have already experimentally demonstrated 100 to 500 mT field amplitude across air gaps as large as 15μm. Simulations indicate that magnetic fields as large as 1.5 T across 50μm inductor gaps are feasible. A simple rearranging of the yoke and pole geometry allows for fabrication of 10+ cm long undulator structures with period lengths between 12.5μm and 1 mm. Such undulators find application both in high average power spontaneous emission sources and, if used in combination with ultrahigh-brightness electron beams, could lead to the realization of low energy compact free-electron lasers. Challenges include electron energy broadening due to wakefields and Joule heating in the electromagnet.

Pole tide triggering of seismicity

NASA Astrophysics Data System (ADS)

Gorshkov, V.

2015-08-01

The influence of the pole tide (PT) on intensity of seismic process is searched on base of Harvard Centroid-moment tensors catalogue (CMT). The normal and shear stresses excited by PT were calculated for each earthquake (EQ) from CMT (32.3 thousands of EQ events after for- and aftershock declustering). There was revealed that there are two maxima of PT influence on weak (less 5.5 magnitudes) thrust-slip EQ near the both extrema (min and max) of shear stress. This influence has 95 % level of statistical significance by Schuster and χ^2 criteria and could explain the 0.6-year periodicity in seismic intensity spectrum. The PT influence on seismicity becomes negligible when PT variations decrease up to 100~mas. This could explain 6-7 years periodicity in seismic intensity spectrum.

Elliptical Chandler pole motions of the Earth and Mars

NASA Astrophysics Data System (ADS)

Barkin, Yury; Ferrandiz, Jose

2010-05-01

In the work the values of the period and eccentricity of Chandler motion of poles of axes of rotation of the Earth and Mars have been determined. The research has been carried out on the basis of developed earlier by authors an intermediate rotary Chandler-Euler motion of the weakly deformable celestial bodies (Barkin, Ferrandiz and Getino, 1996; Barkin, 1998). An influence of a liquid core on Chandler motion of a pole in the given work has not considered. The periods of the specified pole motions make 447.1 d for the Earth and 218.1 d for Mars. In comparison with Euler motions of poles because of elastic properties of planets the Chandler periods are increased accordingly on 142.8 d (about 46.9 %) for the Earth and on 26.2 d (on 13.7 %) for Mars. Values of eccentricities of specified Chandler motions of pole e = √b2 --a2- b (here a both b are smaller and big semi-axes of Chandler ellipse) make 0.09884 for the Earth and 0.3688 for Mars (accordingly, on 21.1 % and 6.2 % more than the appropriate values of eccentricities for models of planets as rigid non-spherical bodies). Axes of an ellipse a also b correspond to the principal equatorial axes of inertia of a planet Ox and Oyfor which the moments of inertia have the smallest valueA and middle value B. The pole of the principal axis of inertia Ox for the Earth is displaced to the west on the angle 14°9285, and the pole of the principal axis of inertia Ox for Mars is displaced to the west on the angle 105°0178 (in the appropriate basic geographical systems of coordinates of the given planets). For ellipticties of Chandler trajectories ɛ = (b- a)-b the values 0.004897 (for the Earth) and 0.07048 (for Mars) have been obtained. The specified values surpass by Euler values of appropriate ellipticties on 46.8 % (in case of the Earth) and on 13.3 % (in the case of Mars). Love number k2describing the elastic properties of planets, were accepted equal 0.30 for the Earth and 0.153 for Mars. Estimations of Chandler periods will well be coordinated to similar estimations of other authors for models of elastic planet in 200-212 d (Konopliv et al., 2006; Zharkov, Gudkova, 2009). The values of eccentricity and ellipticity of Chandler pole motion of the Earth will be coordinated to earlier estimations e=0.096-0.098 and ɛ=0.0046-0.0048 (Barkin, 1998; Barkin, Ferrandiz, 2004), and for Mars have been obtained for the first time. The account of influence of a liquid core on considered parameters of motion of poles of planet with elastic mantle also is discussed in report on the base of author's approach developed in the paper (Ferrandiz, Barkin, 2001). The Barkin's work partially was finacially accepted by Spanish grants, Japanise-Russian grant N-09-02-92113-JF and by RFBR grant N 08-02-00367. References Barkin Yu.V., Ferrandiz J.M., J. Getino (1996) About Applications Angle-Action Variables in Rotation Dynamics of the Deformable Celestial Bodies. (Eds. S. Ferraz-Mello, B. Morrando, J.-E. Arlot) Dynamics, ephemerides and astrometry of the solar system. Proceedings. 172 nd Symposium of the International Astronomical Union, Paris ( France), 3-8 Jul. 1995. 1996, pp. 243-244. Barkin Yu.V. (1998) Unperturbed Chandler's Motion and Perturbation Theory of the Rotational Motion of the Deformable Celestial Bodies. Astronomical and Astrophysical Transactions, v. 17, N3, pp. 431-475. Barkin Yu.V., Ferrandiz J.M. (2004) Some dynamical effects in unperturbed and perturbed Earth rotation caused by elastic properties of the mantle. Journees 2004 'Systems de reference spatio temporals' (20-22 September, 2004, Paris, France). Fundamental Astronomy: New concepts and models for high accuracy observations. Book of abstracts, Observatoire de Paris, pp. 15-16. Ferrandiz, J.M. and Barkin, Yu.V. (2001) Dynamics of the rotational motion of the planet with the elastic mantle, liquid core and with the changeable external shell. Proceedings of International Conference «AstroKazan-2001». Astronomy and geodesy in new millennium (24-29 September 2001), Kazan State University: Publisher «DAS», pp. 123-129. Konopliv A.S., Yoder C.F., Standish E.M., Yuan D.-N. and Sjogren W.L. (2006) A global solution for Mars static and seasonal gravity, Mars orientation, Phobos and Deimos masses, and Mars ephemeris. Icarus, V. 182, pp. 23-50. Zarkov V.N., Gudkova T.V. (2009) The period and Q of the Chandler wobble of Mars. Planetary and Space Science (in press).

Refined Rotational Period, Pole Solution, and Shape Model for (3200) Phaethon

NASA Astrophysics Data System (ADS)

Ansdell, Megan; Meech, Karen J.; Hainaut, Olivier; Buie, Marc W.; Kaluna, Heather; Bauer, James; Dundon, Luke

2014-09-01

(3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048 × 2048 pixel CCD on the University of Hawaii 2.2 m telescope. We utilized light curve inversion to (1) refine (3200) Phaethon's rotational period to P = 3.6032 ± 0.0008 hr; (2) estimate a rotational pole orientation of λ = +85° ± 13° and β = -20° ± 10° and (3) derive a shape model. We also used our extensive light curve data set to estimate the slope parameter of (3200) Phaethon's phase curve as G ~ 0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic latitude supports previous evidence for (3200) Phaethon's origin in the inner main asteroid belt as well as the potential for deeply buried volatiles fueling impulsive yet rare cometary outbursts.

Nonlinear dynamics near resonances of a rotor-active magnetic bearings system with 16-pole legs and time varying stiffness

NASA Astrophysics Data System (ADS)

Wu, R. Q.; Zhang, W.; Yao, M. H.

2018-02-01

In this paper, we analyze the complicated nonlinear dynamics of rotor-active magnetic bearings (rotor-AMB) with 16-pole legs and the time varying stiffness. The magnetic force with 16-pole legs is obtained by applying the electromagnetic theory. The governing equation of motion for rotor-active magnetic bearings is derived by using the Newton's second law. The resulting dimensionless equation of motion for the rotor-AMB system is expressed as a two-degree-of-freedom nonlinear system including the parametric excitation, quadratic and cubic nonlinearities. The averaged equation of the rotor-AMB system is obtained by using the method of multiple scales when the primary parametric resonance and 1/2 subharmonic resonance are taken into account. From the frequency-response curves, it is found that there exist the phenomena of the soft-spring type nonlinearity and the hardening-spring type nonlinearity in the rotor-AMB system. The effects of different parameters on the nonlinear dynamic behaviors of the rotor-AMB system are investigated. The numerical results indicate that the periodic, quasi-periodic and chaotic motions occur alternately in the rotor-AMB system.

Characterization of Lunar Polar Illumination from a Power System Perspective

NASA Technical Reports Server (NTRS)

Fincannon, James

2008-01-01

This paper presents the results of illumination analyses for the lunar south and north pole regions obtained using an independently developed analytical tool and two types of digital elevation models (DEM). One DEM was based on radar height data from Earth observations of the lunar surface and the other was a combination of the radar data with a separate dataset generated using Clementine spacecraft stereo imagery. The analysis tool enables the assessment of illumination at most locations in the lunar polar regions for any time and any year. Maps are presented for both lunar poles for the worst case winter period (the critical power system design and planning bottleneck) and for the more favorable best case summer period. Average illumination maps are presented to help understand general topographic trends over the regions. Energy storage duration maps are presented to assist in power system design. Average illumination fraction, energy storage duration, solar/horizon terrain elevation profiles and illumination fraction profiles are presented for favorable lunar north and south pole sites which have the potential for manned or unmanned spacecraft operations. The format of the data is oriented for use by power system designers to develop mass optimized solar and energy storage systems.

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

Horn, M.E.

A field study and associated risk assessment was conducted to evaluate the potential ecological and human health impacts related to the standard application of five supplemental wood preservatives to 20 electric utility transmission poles. Post-application monitoring for chemical residuals and microbiological effects was conducted over a 17 month post-application period (June 6, 1990--November 7, 1991). The utility wood poles in the study were located in wetland sites of the New York State Adirondack Park. All poles were western red cedar and all had been treated with pentachlorophenol (PCP) prior to installation. At the time supplemental preservatives were applied, the polesmore » had been in service for approximately 40 years. Groundwater, surface water, and soil around each treated pole were monitored for release of active ingredients, organic carriers and subsequent degradation products of the commercial wood preservatives. The analytes were as follows: chlorpyrifos, 1,1,1-trichloroethane, creosote, 2,4-dinitrophenol, fluoride, chromium, arsenic, copper, naphthenate, sodium methyl dithiocarbamate and methyl isothiocyanate. Ecological response to chemical exposure was estimated by means of measuring soil gases (carbon dioxide and methane), soil macroinvertebrate populations and soil microbial biomass. Results from near-pole post-treatment sampling were compared to pre-treatment samples and reference plots used to establish preapplication biological conditions and background levels of wood preservative constituents.« less

Evaluation of Apple Maturity with Two Types of Dielectric Probes.

PubMed

Kafarski, Marcin; Wilczek, Andrzej; Szypłowska, Agnieszka; Lewandowski, Arkadiusz; Pieczywek, Piotr; Janik, Grzegorz; Skierucha, Wojciech

2018-01-04

The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed using a multipole dielectric relaxation model, which assumes three active relaxation processes: primary α-process (water relaxation) and two secondary processes caused by solid-water-ion interactions α' (bound water relaxations), as well as β' (Maxwell-Wagner effect). The performance of two designs of the dielectric probe was compared: a classical coaxial open-ended probe (OE probe) and an open-ended probe with a prolonged central conductor in a form of an antenna (OE-A-probe). The OE-A probe increases the measurement volume and consequently extends the range of applications to other materials, like granulated agricultural products, soils, or liquid suspensions. However, its measurement frequency range is limited as compared to the OE probe because, above 1.5 GHz, the probe with the antenna generates higher propagation modes and the applied calibrations and calculations are not sufficient. It was shown that data from measurements using the OE-A probe gave slightly stronger correlations with apples' quality parameters than using the typical OE probe. Additionally, we have compared twelve multipole fitting models with different combinations of poles (eight three-pole and four two-pole models). It was shown that the best fit is obtained using a two-pole model for data collected for the OE-A probe and a three-pole model for the OE probe, using only Cole-Cole poles in both cases.

Evaluation of Apple Maturity with Two Types of Dielectric Probes

PubMed Central

Kafarski, Marcin; Szypłowska, Agnieszka; Lewandowski, Arkadiusz; Pieczywek, Piotr; Janik, Grzegorz; Skierucha, Wojciech

2018-01-01

The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed using a multipole dielectric relaxation model, which assumes three active relaxation processes: primary α-process (water relaxation) and two secondary processes caused by solid-water-ion interactions α’ (bound water relaxations), as well as β’ (Maxwell-Wagner effect). The performance of two designs of the dielectric probe was compared: a classical coaxial open-ended probe (OE probe) and an open-ended probe with a prolonged central conductor in a form of an antenna (OE-A-probe). The OE-A probe increases the measurement volume and consequently extends the range of applications to other materials, like granulated agricultural products, soils, or liquid suspensions. However, its measurement frequency range is limited as compared to the OE probe because, above 1.5 GHz, the probe with the antenna generates higher propagation modes and the applied calibrations and calculations are not sufficient. It was shown that data from measurements using the OE-A probe gave slightly stronger correlations with apples’ quality parameters than using the typical OE probe. Additionally, we have compared twelve multipole fitting models with different combinations of poles (eight three-pole and four two-pole models). It was shown that the best fit is obtained using a two-pole model for data collected for the OE-A probe and a three-pole model for the OE probe, using only Cole-Cole poles in both cases. PMID:29300324

Determining titan's spin state from cassini radar images

USGS Publications Warehouse

Stiles, B.W.; Kirk, R.L.; Lorenz, R.D.; Hensley, S.; Lee, E.; Ostro, S.J.; Allison, M.D.; Callahan, P.S.; Gim, Y.; Iess, L.; Del Marmo, P.P.; Hamilton, G.; Johnson, W.T.K.; West, R.D.

2008-01-01

For some 19 areas of Titan's surface, the Cassini RADAR instrument has obtained synthetic aperture radar (SAR) images during two different flybys. The time interval between flybys varies from several weeks to two years. We have used the apparent misregistration (by 10-30 km) of features between separate flybys to construct a refined model of Titan's spin state, estimating six parameters: north pole right ascension and declination, spin rate, and these quantities' first time derivatives We determine a pole location with right ascension of 39.48 degrees and declination of 83.43 degrees corresponding to a 0.3 degree obliquity. We determine the spin rate to be 22.5781 deg day -1 or 0.001 deg day-1 faster than the synchronous spin rate. Our estimated corrections to the pole and spin rate exceed their corresponding standard errors by factors of 80 and 8, respectively. We also found that the rate of change in the pole right ascension is -30 deg century-1, ten times faster than right ascension rate of change for the orbit normal. The spin rate is increasing at a rate of 0.05 deg day -1 per century. We observed no significant change in pole declination over the period for which we have data. Applying our pole correction reduces the feature misregistration from tens of km to 3 km. Applying the spin rate and derivative corrections further reduces the misregistration to 1.2 km. ?? 2008. The American Astronomical Society. All rights reserved.

Simulation study of poled low-water ionomers with different architectures

NASA Astrophysics Data System (ADS)

Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

2011-11-01

The role of the ionomer architecture in the formation of ordered structures in poled membranes is investigated by molecular dynamics computer simulations. It is shown that the length of the sidechain Ls controls both the areal density of cylindrical aggregates Nc and the diameter of these cylinders in the poled membrane. The backbone segment length Lb tunes the average diameter Ds of cylindrical clusters and the average number of sulfonates Ns in each cluster. A simple empirical formula is noted for the dependence of the number density of induced rod-like aggregates on the sidechain length Ls within the parameter range considered in this study.

Multi-Body Orbit Architectures for Lunar South Pole Coverage

NASA Technical Reports Server (NTRS)

Grebow, D. J.; Ozimek, M. T.; Howell, K. C.; Folta, D. C.

2006-01-01

A potential ground station at the lunar south pole has prompted studies of orbit architectures that ensure adequate coverage. Constant communications can be achieved with two spacecraft in different combinations of Earth-Moon libration point orbits. Halo and vertical families, as well as other orbits near L1 and L2 are considered. The investigation includes detailed results using nine different orbits with periods ranging from 7 to 16 days. Natural solutions are generated in a full ephemeris model, including solar perturbations. A preliminary station-keeping analysis is also completed.

The polarized distribution of poly(A+)-mRNA-induced functional ion channels in the Xenopus oocyte plasma membrane is prevented by anticytoskeletal drugs.

PubMed

Peter, A B; Schittny, J C; Niggli, V; Reuter, H; Sigel, E

1991-08-01

Foreign mRNA was expressed in Xenopus laevis oocytes. Newly expressed ion currents localized in defined plasma membrane areas were measured using the two-electrode voltage clamp technique in combination with a specially designed chamber, that exposed only part of the surface on the oocytes to channel agonists or inhibitors. Newly expressed currents were found to be unequally distributed in the surface membrane of the oocyte. This asymmetry was most pronounced during the early phase of expression, when channels could almost exclusively be detected in the animal hemisphere of the oocyte. 4 d after injection of the mRNA, or later, channels could be found at a threefold higher density at the animal than at the vegetal pole area. The pattern of distribution was observed to be similar with various ion channels expressed from crude tissue mRNA and from cRNAs coding for rat GABAA receptor channel subunits. Electron microscopical analysis revealed very similar microvilli patterns at both oocyte pole areas. Thus, the asymmetric current distribution is not due to asymmetric surface structure. Upon incubation during the expression period in either colchicine or cytochalasin D, the current density was found to be equal in both pole areas. The inactive control substance beta-lumicolchicine had no effect on the asymmetry of distribution. Colchicine was without effect on the amplitude of the expressed whole cell current. Our measurements reveal a pathway for plasma membrane protein expression endogenous to the Xenopus oocyte, that may contribute to the formation and maintenance of polarity of this highly organized cell.

Preliminary Study of Methods for Upgrading USGS Antarctic Seismological Capability

USGS Publications Warehouse

Holcomb, L. Gary

1982-01-01

Purpose The purpose of this study is to evaluate potential methods for obtaining higher quality seismic data from Antarctica. Currently, USGS-sponsored WWSSN stations are located at Scott Base, Sanae Base, and at South Pole Station. Scott and Sanae Stations are located near the coast; data obtained from coastal installations are normally degraded by noise generated by ocean wave action on the coast. Operations at South Pole are rather difficult because of the severe environmental characteristics and the extended logistics which are required to provide supplies and operating personnel to its remote location. Short-period data quality from Pole Station has been moderately high with a short-period magnification of 100K at 1Hz. Long-period magnifications have been rather low (<1K @ 15 s period). Recent relocation of the seismic recording facilities at South Pole Station as a result of the construction of a completely new station facility has caused serious degradation of the data quality due to faulty installation techniques. Repairs have been implemented to remedy these deficiencies and to regain the data quality which existed before the move to new facilities. However, the technology being used at South Pole Station is of WWSSN vintage; as a result it is about 20 years old. Much has been learned about achieving higher magnifications since the WWSSN was designed. This study will evaluate the feasibility of applying recent technological advances to Antarctic seismology. Seismological data from the Antarctic Continent is important to the world's seismological community because of the Antarctic's unique geographic position on the globe. Land masses are scarce in that part of the world; the Antarctic sits right in the middle of the void. Therefore, its data are important for completing the data set for the southern hemisphere. Upgrading the USGS seismic capability in the Antarctic should also prove to be a wise investment from another point of view. Although the initial costs of the Antarctic upgrade program would be high, and the cost of routine maintenance and support would be greater than in other parts of the world, the ease of upgrading is aided by the unique nonpolitical aspect of the continent. In addition, the danger of losing our investment due to political unrest or change is almost zero. In the past, political complications have severely impacted operations at several SRO stations. Therefore, an effort to improve data quality from the Antarctic would be a prudent long-term investment.

A QUARTER-CENTURY OF OBSERVATIONS OF COMET 10P/TEMPEL 2 AT LOWELL OBSERVATORY: CONTINUED SPIN-DOWN, COMA MORPHOLOGY, PRODUCTION RATES, AND NUMERICAL MODELING

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

Knight, Matthew M.; Schleicher, David G.; Schwieterman, Edward W.

2012-11-01

We report on photometry and imaging of Comet 10P/Tempel 2 obtained at Lowell Observatory from 1983 through 2011. We measured a nucleus rotation period of 8.950 {+-} 0.002 hr from 16 nights of imaging acquired between 2010 September and 2011 January. This rotation period is longer than the period we previously measured in 1999, which was itself longer than the period measured in 1988, and demonstrates that Tempel 2 is continuing to spin down, presumably due to torques caused by asymmetric outgassing. A nearly linear jet was observed which varied little during a rotation cycle in both R and CNmore » images acquired during the 1999 and 2010 apparitions. We measured the projected direction of this jet throughout the two apparitions and, under the assumption that the source region of the jet was near the comet's pole, determined a rotational pole direction of R.A./decl. = 151 Degree-Sign /+59 Degree-Sign from CN measurements and R.A./decl. = 173 Degree-Sign /+57 Degree-Sign from dust measurements (we estimate a circular uncertainty of 3 Degree-Sign for CN and 4 Degree-Sign for dust). Different combinations of effects likely bias both gas and dust solutions and we elected to average these solutions for a final pole direction of R.A./decl. = 162 Degree-Sign {+-} 11 Degree-Sign /+58 Degree-Sign {+-} 1 Degree-Sign . Photoelectric photometry was acquired on 3 nights in 1983, 2 nights in 1988, 19 nights in 1999/2000, and 10 nights in 2010/2011. The activity exhibited a steep 'turn-on' {approx}3 months prior to perihelion (the exact timing of which varies) and a relatively smooth decline after perihelion. The activity during the 1999 and 2010 apparitions was similar; limited data in 1983 and 1988 (along with IUE data from the literature) were systematically higher and the difference cannot be explained entirely by the smaller perihelion distance. We measured a 'typical' composition, in agreement with previous investigators. Monte Carlo numerical modeling with our pole solution best replicated the observed coma morphology for a source region located near a comet latitude of +80 Degree-Sign and having a radius of {approx}10 Degree-Sign . Our model reproduced the seasonal changes in activity, suggesting that the majority of Tempel 2's activity originates from a small active region located near the pole. We also find that a cosine-squared solar angle function gives the best fit as compared to a standard cosine function.« less

Quadratic soliton self-reflection at a quadratically nonlinear interface

NASA Astrophysics Data System (ADS)

Jankovic, Ladislav; Kim, Hongki; Stegeman, George; Carrasco, Silvia; Torner, Lluis; Katz, Mordechai

2003-11-01

The reflection of bulk quadratic solutions incident onto a quadratically nonlinear interface in periodically poled potassium titanyl phosphate was observed. The interface consisted of the boundary between two quasi-phase-matched regions displaced from each other by a half-period. At high intensities and small angles of incidence the soliton is reflected.

Rotational-oscillational motions of the nonrigid Earth about the center of mass

NASA Astrophysics Data System (ADS)

Bondarenko, V. V.; Perepelkin, V. V.

2009-10-01

We use the model of a nearly axisymmetric viscoelastic rigid body to study perturbed rotational-oscillational motions of the Earth's pole. We point out that the Chandler component of oscillations is of celestial-mechanics nature and is caused by the gravitational-tidal actions of the Sun and the Moon. We analyze the pole oscillation excitation mechanism at a frequency close to the Chandler frequency and show that the undamped pole oscillations are caused by the resonance harmonic of the external perturbation at a frequency close to the free nutation frequency. We discuss whether it is possible to solve the problem of constructing a short-term forecast of the pole motion on the basis of a polynomial filter obtained by the least-squares method without taking into account small-scale oscillations caused by wide-band random factors of arbitrary physical nature. In the present paper, we perform numerical simulation of tidal inhomogeneities in the Earth's axial rotation. Attention is mainly paid to the analysis of day length variations on short time intervals with periods less than or equal to one year (interannual oscillations) and to their forecast.

Minimax rational approximation of the Fermi-Dirac distribution

DOE PAGES

Moussa, Jonathan E.

2016-10-27

Accurate rational approximations of the Fermi-Dirac distribution are a useful component in many numerical algorithms for electronic structure calculations. The best known approximations use O(log(βΔ)log(ϵ –1)) poles to achieve an error tolerance ϵ at temperature β –1 over an energy interval Δ. We apply minimax approximation to reduce the number of poles by a factor of four and replace Δ with Δ occ, the occupied energy interval. Furthermore, this is particularly beneficial when Δ >> Δ occ, such as in electronic structure calculations that use a large basis set.

Parametric down-conversion with nonideal and random quasi-phase-matching

NASA Astrophysics Data System (ADS)

Yang, Chun-Yao; Lin, Chun; Liljestrand, Charlotte; Su, Wei-Min; Canalias, Carlota; Chuu, Chih-Sung

2016-05-01

Quasi-phase-matching (QPM) has enriched the capacity of parametric down-conversion (PDC) in generating biphotons for many fundamental tests and advanced applications. However, it is not clear how the nonidealities and randomness in the QPM grating of a parametric down-converter may affect the quantum properties of the biphotons. This paper intends to provide insights into the interplay between PDC and nonideal or random QPM structures. Using a periodically poled nonlinear crystal with short periodicity, we conduct experimental and theoretical studies of PDC subject to nonideal duty cycle and random errors in domain lengths. We report the observation of biphotons emerging through noncritical birefringent-phasematching, which is impossible to occur in PDC with an ideal QPM grating, and a biphoton spectrum determined by the details of nonidealities and randomness. We also observed QPM biphotons with a diminished strength. These features are both confirmed by our theory. Our work provides new perspectives for biphoton engineering with QPM.

Evidence for free precession in a pulsar

PubMed

Stairs; Lyne; Shemar

2000-08-03

Pulsars are rotating neutron stars that produce lighthouse-like beams of radio emission from their magnetic poles. The observed pulse of emission enables their rotation rates to be measured with great precision. For some young pulsars, this provides a means of studying the interior structure of neutron stars. Most pulsars have stable pulse shapes, and slow down steadily (for example, see ref. 20). Here we report the discovery of long-term, highly periodic and correlated variations in both the pulse shape and the rate of slow-down of the pulsar PSR B1828-11. The variations are best described as harmonically related sinusoids, with periods of approximately 1,000, 500 and 250 days, probably resulting from precession of the spin axis caused by an asymmetry in the shape of the pulsar. This is difficult to understand theoretically, because torque-free precession of a solitary pulsar should be damped out by the vortices in its superfluid interior.

Coupled Riccati equations for complex plane constraint

NASA Technical Reports Server (NTRS)

Strong, Kristin M.; Sesak, John R.

1991-01-01

A new Linear Quadratic Gaussian design method is presented which provides prescribed imaginary axis pole placement for optimal control and estimation systems. This procedure contributes another degree of design freedom to flexible spacecraft control. Current design methods which interject modal damping into the system tend to have little affect on modal frequencies, i.e., they predictably shift open plant poles horizontally in the complex plane to form the closed loop controller or estimator pole constellation, but make little provision for vertical (imaginary axis) pole shifts. Imaginary axis shifts which reduce the closed loop model frequencies (the bandwidths) are desirable since they reduce the sensitivity of the system to noise disturbances. The new method drives the closed loop modal frequencies to predictable (specified) levels, frequencies as low as zero rad/sec (real axis pole placement) can be achieved. The design procedure works through rotational and translational destabilizations of the plant, and a coupling of two independently solved algebraic Riccati equations through a structured state weighting matrix. Two new concepts, gain transference and Q equivalency, are introduced and their use shown.

Strong dipole and higher multi-pole Mie resonance modes with all-dielectric nanoring metasurfaces structure

NASA Astrophysics Data System (ADS)

Zhu, Huihui; Jing, Xufeng; Zhou, Pengwei

2018-01-01

Strong electric and magnetic dipole in infrared region and higher order multi-pole resonance at visible wavelengths are observed in all-dielectric nanoring metasurfaces. We discuss some of the parameters that influence the optical response of the dielectric nanoring. Adjustment of nanoring radius (inner radius and outer radius) and height can change the absorption intensity and the resonance peaks. Dipole, quadrupole, six-pole and ten-pole resonance modes can be found in the silicon nanoring at resonance wavelength. The transmission spectrum of nanoring with high Q-factor and contrast is achieved with appropriate parameters. Further the nanoring is used to application of sensing in which the sensitivity reaches 228 nm/RIU. This research is an important step to understand resonance in silicon nanoring and paves way for designing some optic devices such as sensor, nanoantennas, and photovoltaics.

High-resolution ultrasonic imaging of the posterior segment.

PubMed

Coleman, D Jackson; Silverman, Ronald H; Chabi, Almira; Rondeau, Mark J; Shung, K Kirk; Cannata, Jon; Lincoff, Harvey

2004-07-01

Conventional ophthalmic ultrasonography is performed using 10-megahertz (MHz) transducers. Our aim was to explore the use of higher frequency ultrasound to provide improved resolution of the posterior pole. Prospective case series. One normal subject and 5 subjects with pathologies affecting the posterior coats, including nevii, small melanomas, and macular hole. We modeled the frequency-dependent attenuation of ultrasound across the eye to develop an understanding of the range of frequencies that might be practically applied for imaging of the posterior pole. We compared images of the posterior coats made at 10, 15, and 20 MHz, and 20-MHz ultrasound images of pathologies with 10-MHz ultrasound and optical coherence tomography (OCT). Ability to resolve normal and pathologic structures affecting posterior coats of the eye. Modeling showed that frequencies of 20 to 25 MHz might be used for posterior pole imaging. Twenty-megahertz images allowed differentiation of the retina, choroid, and sclera. In addition, at 20 MHz the retina showed banding patterns suggesting an internal structure comparable in many respects to that seen in OCT and histology. Images of ocular pathology provided much improved detail relative to 10-MHz images and deeper penetration than OCT. Twenty-megahertz ultrasound can be practically employed for imaging of the posterior pole of the eye, providing a 2-fold improvement in resolution relative to conventional 10-MHz instruments. Although not providing the resolution of OCT, ultrasound can be used in the presence of optical opacities and allows evaluation of deeper tissue structures.

Characteristics of optical parametric oscillator synchronously pumped by Yb:KGW laser and based on periodically poled potassium titanyl phosphate crystal

NASA Astrophysics Data System (ADS)

Vengelis, Julius; Tumas, Adomas; Pipinytė, Ieva; Kuliešaitė, Miglė; Tamulienė, Viktorija; Jarutis, Vygandas; Grigonis, Rimantas; Sirutkaitis, Valdas

2018-03-01

We present experimental data and numerical simulation results obtained during investigation of synchronously pumped optical parametric oscillator (SPOPO) pumped by femtosecond Yb:KGW laser (central wavelength at 1033 nm). The nonlinear medium for parametric generation was periodically poled potassium titanyl phosphate crystal (PPKTP). Maximum parametric light conversion efficiency from pump power to signal power was more than 37.5% at λs=1530 nm wavelength, whereas the achieved signal wave continuous tuning range was from 1470 nm to 1970 nm with signal pulse durations ranging from 91 fs to roughly 280 fs. We demonstrated wavelength tuning by changing cavity length and PPKTP crystal grating period and also discussed net cavity group delay dispersion (GDD) influence on SPOPO output radiation characteristics. The achieved high pump to signal conversion efficiency and easy wavelength tuning make this device a very promising alternative to Ti:sapphire based SPOPOs as a source of continuously tunable femtosecond laser radiation in the near and mid-IR range.

Summer at Saturn's North Pole: Seasonal Changes Seen by ISS & CIRS on Cassini, and VLT on the Ground

NASA Astrophysics Data System (ADS)

Sayanagi, K. M.; Blalock, J.; Fletcher, L. N.; Ingersoll, A. P.; Dyudina, U.; Ewald, S. P.

2016-12-01

We report seasonal changes in Saturn's north polar vortex seen by Cassini ISS, Cassini CIRS, and ground-based VLT VISIR thermal infrared observations. ISS observation of Saturn's northern high latitudes show that a reflective, bright polar spot has formed over the north pole, seen first in images captured in 2016. This coincides with the warm cyclonic north polar vortex that has been steadily warming since it was first discovered in 2007 by Cassini CIRS. The reflective spot was not present when the north pole was observed during the previous period of Cassini spacecraft's high-inclination orbits in 2012. In 2012, the concentration of light-scattering aerosols within 2-degree latitude of the north pole appeared to be less than that of the surrounding region, and appeared dark in all ISS filters. The new bright spot over the north pole is similar to that over the south pole seen in 2007. In 2007, Saturn was approaching the equinox of 2009 and south pole had been continuously illuminated since the previous equinox in 1995. The bright spot over the summer south pole in 2007 was hypothesized to consist of aerosols produced by ultraviolet photodissociation of hydrocarbon molecules; we follow this hypothesis to propose that the new bright spot over the north pole is also produced by the same mechanism. We argue that, in 2012 (3 years after equinox), the north polar bright spot hadn't formed because the ultraviolet insolation was not sufficient to produce enough photochemical aerosols. The new polar bright cloud formation is consistent with the rising abundances of stratospheric hydrocarbons (potential precursors to aerosol formation) over the north polar region as tracked by CIRS (Fletcher et al., 2015). In addition to ISS images, we also present CIRS and VLT-VISIR thermal maps of the northern high latitudes as the new north polar bright spot is expected to have implications on radiative energy balance. Our research has been supported by the Cassini Project, NASA grants OPR NNX11AM45G, CDAPS NNX15AD33G, PATM NNX14AK07G, and NSF grant AAG 1212216.

Saturn's aurora observed by the Cassini camera at visible wavelengths

NASA Astrophysics Data System (ADS)

Dyudina, Ulyana A.; Ingersoll, Andrew P.; Ewald, Shawn P.; Wellington, Danika

2016-01-01

The first observations of Saturn's visible-wavelength aurora were made by the Cassini camera. The aurora was observed between 2006 and 2013 in the northern and southern hemispheres. The color of the aurora changes from pink at a few hundred km above the horizon to purple at 1000-1500 km above the horizon. The spectrum observed in 9 filters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with laboratory simulated auroras. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs between 70° and 80° latitude north and between 65° and 80° latitude south, which sometimes spiral around the pole, and sometimes form double arcs. A large 10,000-km-scale longitudinal brightness structure persists for more than 100 h. This structure rotates approximately together with Saturn. On top of the large steady structure, the auroras brighten suddenly on the timescales of a few minutes. These brightenings repeat with a period of ∼1 h. Smaller, 1000-km-scale structures may move faster or lag behind Saturn's rotation on timescales of tens of minutes. The persistence of nearly-corotating large bright longitudinal structure in the auroral oval seen in two movies spanning 8 and 11 rotations gives an estimate on the period of 10.65 ± 0.15 h for 2009 in the northern oval and 10.8 ± 0.1 h for 2012 in the southern oval. The 2009 north aurora period is close to the north branch of Saturn Kilometric Radiation (SKR) detected at that time.

Habitat selection of a declining white-tailed deer herd in the central Black Hills, South Dakota and Wyoming

NASA Astrophysics Data System (ADS)

Deperno, Christopher Shannon

Habitat selection, survival rates, the Black Hills National Forest Habitat Capability Model (HABCAP), and the USDA Forest Service Geographic Information System (GIS) data base were evaluated for a declining white-tailed deer (Odocoileus virginianus dacotensis) herd in the central Black Hills of South Dakota and Wyoming. From July 1993 through July 1996, 73 adult and yearling female and 12 adult and yearling male white-tailed deer were radiocollared and visually monitored. Habitat information was collected at 4,662 white-tailed deer locations and 1,087 random locations. Natural mortality (71%) was the primary cause of female mortality, followed by harvest (22.5%) and accidental causes (6.5%). More females died in spring (53.2%) than in fall (22.6%), winter (14.5%), or summer (9.7%). Male mortality resulted from hunting in fall (66.7%) and natural causes in spring (33.3%). Survival rates for all deer by year were 62.1% in 1993, 51.1% in 1994, 56.4% in 1995, and 53.9% in 1996 and were similar (P = 0.691) across years. During winter, white-tailed deer selected ponderosa pine- (Pinus ponderosa ) deciduous and burned pine cover types. Overstory-understory habitats selected included pine/grass-forb, pine/bearberry (Arctostaphylos uva-ursi), pine/snowberry (Symphoricarpos albus), burned pine/grass-forb, and pine/shrub habitats. Structural stages selected included sapling-pole pine stands with >70% canopy cover, burned pine sapling-pole and saw-timber stands with <40% canopy cover. Bedding locations were represented by saw-timber pine structural stages with >40% canopy cover and all sapling-pole pine structural stages; sapling-pole stands with >70% canopy cover received the greatest use. White-tailed deer primarily fed in pine saw-timber structural stage with less than 40% canopy cover. Overall, selected habitats contained lower amounts of grass/forb, shrubs, and litter than random locations. Male and female deer generally bedded in areas that were characterized by greater horizontal cover than feeding and random sites. When feeding and bedding sites were combined males selected areas that were characterized by greater levels of horizontal cover than females. During summer, white-tailed deer selected pine-deciduous, aspen (Populus tremuloides), aspen-coniferous, spruce (Picea glauca), and spruce-deciduous cover types. Overstory-understory habitats selected included pine/juniper (Juniperus communis), aspen/shrubs, spruce/juniper, and spruce/shrub habitats. Structural stages selected included pine, aspen, and spruce sapling pole stands with all levels (0--40%, 41--70%, 71--100%) of canopy cover. All habitat types (i.e., pine, aspen, and spruce) were used as bedding locations with pine sapling-pole structural stages with >70% canopy cover used most, whereas pine saw-timber structural stage with less than 40% canopy cover was primarily used for feeding. Females bedded in areas that were characterized by greater horizontal cover than feeding and random sites, whereas male feeding sites had greater horizontal cover characteristics than bedding or random locations.

Wavelet based comparison of high frequency oscillations in the geodetic and fluid excitation functions of polar motion

NASA Astrophysics Data System (ADS)

Kosek, W.; Popinski, W.; Niedzielski, T.

2011-10-01

It has been already shown that short period oscillations in polar motion, with periods less than 100 days, are very chaotic and are responsible for increase in short-term prediction errors of pole coordinates data. The wavelet technique enables to compare the geodetic and fluid excitation functions in the high frequency band in many different ways, e.g. by looking at the semblance function. The waveletbased semblance filtering enables determination the common signal in both geodetic and fluid excitation time series. In this paper the considered fluid excitation functions consist of the atmospheric, oceanic and land hydrology excitation functions from ECMWF atmospheric data produced by IERS Associated Product Centre Deutsches GeoForschungsZentrum, Potsdam. The geodetic excitation functions have been computed from the combined IERS pole coordinates data.

Simultaneously phase-matched second- and third-harmonic generation from 1.55 microm radiation in annealed proton-exchanged periodically poled lithium niobate waveguides.

PubMed

Marangoni, M; Lobino, M; Ramponi, R

2006-09-15

Third-harmonic generation (THG) in the cw regime from C-band radiation was achieved in annealed proton-exchanged periodically poled lithium niobate (PPLN) waveguides. By suitable design of fabrication parameters and operating conditions, quasi-phase-matching (QPM) is obtained simultaneously for the second-harmonic generation process (omega-->2omega, first-order QPM) and for the sum-frequency-generation process (omega+2omega-->3omega, third-order QPM), which provides the third harmonic of the pump field. The high overlap between the field profiles of the interacting modes--TM00 at omega and TM10 at 2omega and 3omega--results in what is believed to be the highest ever reported normalized conversion efficiency for THG from telecommunication wavelengths, equal to 0.72%W(-2) cm(-4).

Magnetic field geometry and chemical abundance distribution of the He-strong star CPD -57°3509

NASA Astrophysics Data System (ADS)

Hubrig, S.; Przybilla, N.; Korhonen, H.; Ilyin, I.; Schöller, M.; Järvinen, S. P.; Nieva, M.-F.; Scholz, R.-D.; Kimeswenger, S.; Ramolla, M.; Kholtygin, A. F.; Briquet, M.

2017-10-01

The magnetic field of CPD -57°3509 was recently detected in the framework of the BOB (B fields in OB stars) collaboration. We acquired low-resolution spectropolarimetric observations of CPD -57°3509 with the FOcal Reducer low-dispersion Spectrograph 2 and high-resolution UV-Visual Echelle Spectrograph observations randomly distributed over a few months to search for periodicity, to study the magnetic field geometry and to determine the surface distribution of silicon and helium. We also obtained supplementary photometric observations at a timeline similar to the spectroscopic and spectropolarimetric observations. A period of 6.36 d was detected in the measurements of the mean longitudinal magnetic field. A sinusoidal fit to our measurements allowed us to constrain the magnetic field geometry and estimate the dipole strength in the range of 3.9-4.5 kG. Our application of the Doppler imaging technique revealed the presence of He I spots located around the magnetic poles, with a strong concentration at the positive pole and a weaker one around the negative pole. In contrast, high-concentration Si III spots are located close to the magnetic equator. Furthermore, our analysis of the spectral variability of CPD -57°3509 on short time-scales indicates distinct changes in shape and position of line profiles possibly caused by the presence of β Cep like pulsations. A small periodic variability in line with the changes of the magnetic field strength is clearly seen in the photometric data.

Testing Orbital Parameters as a Hypothesis for the Presence of CO2 Deposits on Mars's South Pole

NASA Astrophysics Data System (ADS)

Bain, Z. M.; Bierson, C. J.

2017-12-01

Observational data of Mars's polar caps shows large deposits of buried CO2 ice in the south polar cap and only seasonal CO2 ice in the north [1]. The lower elevation of Mars's north pole leads to higher surface pressures and therefore more favorable conditions for CO2 ice deposition. There are a few plausible reasons why the CO2 deposits are observed at the southern cap. The first is that during a past epochs of atmospheric collapse, CO2was deposited at both poles and only preserved in the south. Another is that the deposits represent a period where ice was preferentially deposited at the south polar cap. The latter could occur if the orbital parameters were such that the southern cap experienced colder summers (less insolation) than the north. The model of Bierson et. al. 2016 [2] used the observed difference in albedo between the north and the south polar caps and found several periods in the last one million years where deposition was favored at the south polar cap. Here we test if deposition is still favored in the south using the same albedo for both caps. For this work we are using the seasonally resolved KRC model [3]. We varied obliquity, longitude of perihelion, and eccentricity to match their expected values over the last one million years [4]. We modeled the annual CO2 deposition rate in 1,000 year increments. We tested both constant and insolation dependent albedo that was the same at both poles. While we did find periods of deposition on the south pole, this was always in conjunction with deposition in the north in much greater amounts. This finding favors the hypothesis that the deposits are only observed in the southern cap due to the deep pre-existing troughs that allowed the CO2 to be preserved to the modern day. These results also highlight the importance of understanding the observed difference in albedo between the polar caps. [1] Phillips et al. (2011) AAAS, Vol.332 Is.6031 pp.838-841 [2] Bierson et al. (2016) GRL, Vol.43 Is.9 pp.4172-4179 [3] Kieffer (2013) JGR, Vol.118 Is.3 pp.451-470 [4] Laskar et al. (2004) Icarus, Vol.170 Is.2 pp.343-364

The rewritable effects of bonded magnet for large starting torque and high efficiency in the small power single-phase written pole motor

NASA Astrophysics Data System (ADS)

Choi, Jae-Hak; Lee, Sung-Ho

2009-04-01

This paper presents a single-phase written pole motor using a bonded ring magnet for the small power home application. The motor has an exciter pole structure inside the stator and hybrid characteristics of an induction motor and permanent magnet motor. The design parameters and operating characteristics of the hybrid concept motor are investigated to increase starting torque and efficiency, which is most important for the small power home application. Larger starting torque and higher efficiency than those of the conventional induction motor could be obtained by using the rewritable characteristics of bonded magnet on the starting and running conditions.

Closing in on Jupiter North Pole

NASA Image and Video Library

2016-09-02

As NASA's Juno spacecraft closed in on Jupiter for its Aug. 27, 2016 pass, its view grew sharper and fine details in the north polar region became increasingly visible. The JunoCam instrument obtained this view on August 27, about two hours before closest approach, when the spacecraft was 120,000 miles (195,000 kilometers) away from the giant planet (i.e., for Jupiter's center). Unlike the equatorial region's familiar structure of belts and zones, the poles are mottled with rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. Jupiter's poles have not been seen from this perspective since the Pioneer 11 spacecraft flew by the planet in 1974. http://photojournal.jpl.nasa.gov/catalog/PIA21030

Phase degradation in BxGa1-xN films grown at low temperature by metalorganic vapor phase epitaxy

NASA Astrophysics Data System (ADS)

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.; Allerman, Andrew A.; Lee, Stephen R.

2017-04-01

Using metalorganic vapor phase epitaxy, a comprehensive study of BxGa1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750-900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to 7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stacking faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at 362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. Only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.

The Evolution of Networks in Extreme and Isolated Environment

NASA Technical Reports Server (NTRS)

Johnson, Jeffrey C.; Boster, James S.; Palinkas, Lawrence A.

2000-01-01

This article reports on the evolution of network structure as it relates to the formal and informal aspects of social roles in well bounded, isolated groups. Research was conducted at the Amundsen-Scott South Pole Station over a 3-year period. Data was collected on crewmembers' networks of social interaction and personal advice over each of the 8.5-month winters during a time of complete isolation. In addition, data was collected on informal social role structure (e.g., instrumental leadership, expressive leadership). It was hypothesized that development and maintenance of a cohesive group structure was related to the presence of and group consensus on various informal social roles. The study found that core-periphery structures (i.e., reflecting cohesion) in winter-over groups were associated with the presence of critically important informal social roles (e.g., expressive leadership) and high group consensus on such informal roles. On the other hand, the evolution of clique structures (i.e., lack of cohesion) were associated with the absence of critical roles and a lack of consensus on these roles, particularly the critically important role of instrumental leader.

Paleomagnetic study of the northern Ford Ranges, western Marie Byrd Land, West Antarctica: Motion between West and East Antarctica

USGS Publications Warehouse

Luyendyk, B.; Cisowski, S.; Smith, C.; Richard, S.; Kimbrough, D.

1996-01-01

A paleomagnetic study of Paleozoic and Mesozoic crystalline rocks in the northern Ford Ranges of Marie Byrd Land, West Antarctica, has determined a middle Cretaceous (circa 100 Ma) paleomagnetic pole and provided constraints on possible clockwise rotation of these ranges and on the rifting of east Gondwana. The 40Ar/39Ar thermochronology data from the Fosdick Mountains record a period of rapid cooling from ???700??C beginning at ???100 Ma. We relate this to extension, intrusion, and uplift associated with the beginning of rifting between Campbell Plateau and Marie Byrd Land. All rocks from the Fosdick and Chester Mountains are normally polarized. We interpret thermochronology and paleomagnetic data to infer that the region was extensively remagnetized in middle Cretaceous time. Inclinations in samples from the Chester Mountains are less steep than those from the Fosdick Mountains, which we interpret as ???25?? of south tilting of the Chesters. We interpret cooling age data for the time of magnetization to infer that the tilting began after 105 Ma and ended prior to 103 Ma. We further interpret this as constraining the beginning of extension between the Campbell Plateau and western Marie Byrd Land to the interval 105 to 103 Ma. Virtual geomagnetic poles from samples of Early Carboniferous age granodiorite from the western Phillips Mountains lie on the late Paleozoic apparent polar wander path for Australia transferred to Antarctica. Directions from 29 sites in the central and eastern Phillips and Fosdick Mountains give a Middle Cretaceous paleomagnetic pole at 222.3?? E, 70.5?? S (A95 6.1??, KAPPA 20.0). This pole is indistinguishable from other Middle Cretaceous poles for studies further east in Marie Byrd Land. Combining middle Cretaceous poles determined for three other studies of the Antarctic Peninsula. Thurston Island, and the Ruppert-Hobbs coasts with ours gives a Pacific West Antarctic pole at 215.2?? E, 73.5?? S (A95 4.0??, KAPPA 528.9). This pole is discordant by 5?? to 10?? from synthetic mid-Cretaceous East Antarctic reference poles, but the degree of discordance is very sensitive to the choice of the specific reference pole. The lack of native East Antarctic reference poles leaves this analysis inconclusive. Accepting 10?? of discordance, we favor an interpretation where Pacific West Antarctic crustal domains or microplates have rotated clockwise 40?? to 90?? and translated a few degrees away from East Antarctica during Late Cretaceous time.

Premier pôle paléomagnétique, d'âge Moscovien contraint par un test du pli, obtenu dans le bassin d'Illizi (Craton saharien, Algérie)First palaeomagnetic pole, of Moscovian age constrained by a fold test, in the Illizi Basin (Saharan Craton, Algeria)

NASA Astrophysics Data System (ADS)

Bayou, Boualem; Derder, Mohamed El-Messaoud; Henry, Bernard; Djellit, Hamou; Amenna, Mohamed

Palaeomagnetic study, carried out in the Moscovian (˜305 Ma) formation in the Edjeleh anticline, shows the existence of three magnetisation components. Two of them are probably Cenozoic and Permian remagnetisations. The third component determined by both well defined ChRMs and remagnetisation circles analysis passes the fold test. Because the folding started before or during the Stephano-Autunian, this third component is the primary magnetisation. Its palaeomagnetic pole (28.3°S, 58.9°E), close to other poles from the Saharan platform obtained from neighbouring periods but without palaeomagnetic tests, confirms the age of these last data. To cite this article: B. Bayou et al., C. R. Geoscience 334 (2002) 81-87.

Late 20th Century increase in South Pole snow accumulation

USGS Publications Warehouse

Mosley-Thompson, E.; Paskievitch, J.F.; Gow, A.J.; Thompson, L.G.

1999-01-01

A compilation of the 37-year history of net accumulation at the South Pole [Mosley-Thompson et al., 1995] suggests an increase in net annual accumulation since 1965. This record is sporadic and its quality is compromised by spatially restricted observations and nonsystematic measurement procedures. Results from a new, spatially extensive network of 236 accumulation poles document that the current 5-year (1992-1997) average annual net accumulation at the South Pole is 84.5??8.9 mm water equivalent (w.e.). This accumulation rate reflects a 30% increase since the 1960s when the best, although not optimal, records indicate that it was 65 mm w.e. Identification of two prominent beta radioactivity horizons (1954/1955 and 1964/1965) in six firn cores confirms an increase in accumulation since 1965. Viewed from a longer perspective of accumulation provided by ice cores and a snow mine study, the net accumulation of the 30-year period, 1965-1994, is the highest 30-year average of this millennium. Limited data suggest this recent accumulation increase extends beyond the South Pole region and may be characteristic of the high East Antarctic Plateau. Enhanced accumulation over the polar ice sheets has been identified as a potential early indicator of warmer sea surface temperatures and may offset a portion of the current rise in global sea level. Copyright 1999 by the American Geophysical Union.

Broadband continuous-variable entanglement source using a chirped poling nonlinear crystal

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

Zhao, J. S.; Sun, L.; Yu, X. Q.

2010-01-15

Aperiodically poled nonlinear crystal can be used as a broadband continuous-variable entanglement source and has strong stability under perturbations. We study the conversion dynamics of the sum-frequency generation and the quantum correlation of the two pump fields in a chirped-structure nonlinear crystal using the quantum stochastic method. The results show that there exists a frequency window for the pumps where two optical fields can perform efficient upconversion. The two pump fields are demonstrated to be entangled in the window and the chirped-structure crystal can be used as a continuous-variable entanglement source with a broad response bandwidth.

23 CFR 750.711 - Structures which have never displayed advertising material.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Structures which have never displayed advertising... RIGHT-OF-WAY AND ENVIRONMENT HIGHWAY BEAUTIFICATION Outdoor Advertising Control § 750.711 Structures which have never displayed advertising material. Structures, including poles, which have never displayed...

CENP-W Plays a Role in Maintaining Bipolar Spindle Structure

PubMed Central

Kaczmarczyk, Agnieszka; Sullivan, Kevin F.

2014-01-01

The CENP-W/T complex was previously reported to be required for mitosis. HeLa cells depleted of CENP-W displayed profound mitotic defects, with mitotic timing delay, disorganized prometaphases and multipolar spindles as major phenotypic consequences. In this study, we examined the process of multipolar spindle formation induced by CENP-W depletion. Depletion of CENP-W in HeLa cells labeled with histone H2B and tubulin fluorescent proteins induced rapid fragmentation of originally bipolar spindles in a high proportion of cells. CENP-W depletion was associated with depletion of Hec1 at kinetochores. The possibility of promiscuous centrosomal duplication was ruled out by immunofluorescent examination of centrioles. However, centrioles were frequently observed to be abnormally split. In addition, a large proportion of the supernumerary poles lacked centrioles, but were positively stained with different centrosomal markers. These observations suggested that perturbation in spindle force distribution caused by defective kinetochores could contribute to a mechanical mechanism for spindle pole disruption. ‘Spindle free’ nocodazole arrested cells did not exhibit pole fragmentation after CENP-W depletion, showing that pole fragmentation is microtubule dependent. Inhibition of centrosome separation by monastrol reduced the incidence of spindle pole fragmentation, indicating that Eg5 plays a role in spindle pole disruption. Surprisingly, CENP-W depletion rescued the monopolar spindle phenotype of monastrol treatment, with an increased frequency of bipolar spindles observed after CENP-W RNAi. We overexpressed the microtubule cross-linking protein TPX2 to create spindle poles stabilized by the microtubule cross-linking activity of TPX2. Spindle pole fragmentation was suppressed in a TPX2-dependent fashion. We propose that CENP-W, by influencing proper kinetochore assembly, particularly microtubule docking sites, can confer spindle pole resistance to traction forces exerted by motor proteins during chromosome congression. Taken together, our findings are consistent with a model in which centrosome integrity is controlled by the pathways regulating kinetochore-microtubule attachment stability. PMID:25329824

Trolling may intensify exploitation in crappie fisheries

USGS Publications Warehouse

Meals, K. O.; Dunn, A. W.; Miranda, Leandro E.

2012-01-01

In some parts of the USA, anglers targeting crappies Pomoxis spp. are transitioning from mostly stationary angling with a single pole around submerged structures to using multiple poles while drifting with the wind or under power. This shift in fishing methods could result in a change in catch efficiency, possibly increasing exploitation rates to levels that would be of concern to managers. We studied the catch statistics of anglers fishing while trolling with multiple poles (trollers) and those fishing with single poles (polers) in Mississippi reservoirs. Specifically, we tested whether (1) various catch statistics differed between trollers and polers, (2) catch rates of trollers were related to the number of poles fished, and (3) trollers could raise exploitation rates to potentially unsustainable levels. Results showed that participation in the crappie fisheries was about equally split between polers and trollers. In spring, 90% of crappie anglers were polers; in summer, 85% of crappie anglers were trollers. The size of harvested crappies was similar for the two angler groups, but the catch per hour was almost three times higher for trollers than for polers. Catch rates by trollers were directly correlated to the number of poles fished, although the relationship flattened as the number of poles increased. The average harvest rate for one troller fishing with three poles was similar to the harvest rate obtained by one poler. Simulations predicted that at the existing mix of about 50% polers and 50% trollers and with no restrictions on the number of poles used by trollers, exploitation of crappies is about 1.3 times higher than that in a polers-only fishery; under a scenario in which 100% of crappie anglers were trollers, exploitation was forecasted to increase to about 1.7 times the polers-only rate. The efficiency of trolling for crappies should be of concern to fishery managers because crappie fisheries are mostly consumptive and may increase exploitation rates to unsustainable levels.

Thermal maps of Jupiter - Spatial organization and time dependence of stratospheric temperatures, 1980 to 1990

NASA Technical Reports Server (NTRS)

Orton, Glenn S.; Friedson, A. James; Baines, Kevin H.; Martin, Terry Z.; West, Robert A.; Caldwell, John; Hammel, Heidi B.; Bergstralh, Jay T.; Malcolm, Michael E.

1991-01-01

The spatial organization and time dependence of Jupiter's stratospheric temperatures have been measured by observing thermal emission from the 7.8-micrometer CH4 band. These temperatures, observed through the greater part of a Jovian year, exhibit the influence of seasonal radiative forcing. Distinct bands of high temperature are located at the poles and midlatitudes, while the equator alternates between warm and cold with a period of approximately 4 years. Substantial longitudinal variability is often observed within the warm midlatitude bands, and occasionally elsewhere on the planet. This variability includes small, localized structures, as well as large-scale waves with wavelengths longer than about 30,000 kilometers. The amplitudes of the waves vary on a time scale of about 1 month; structures on a smaller scale may have lifetimes of only days. Waves observed in 1985, 1987, and 1988 propagated with group velocities less than + or - 30 meters/sec.

WISEP J060738.65+242953.4: A NEARBY POLE-ON L8 BROWN DWARF WITH RADIO EMISSION

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

Gizis, John E.; Paudel, Rishi; Williams, Peter K. G.

2016-11-01

We present a simultaneous, multi-wavelength campaign targeting the nearby (7.2 pc) L8/L9 (optical/near-infrared) dwarf WISEP J060738.65+242953.4 in the mid-infrared, radio, and optical. Spitzer Space Telescope observations show no variability at the 0.2% level over 10 hr each in the 3.6 and 4.5 μ m bands. Kepler K2 monitoring over 36 days in Campaign 0 rules out stable periodic signals in the optical with amplitudes greater than 1.5% and periods between 1.5 hr and 2 days. Non-simultaneous Gemini optical spectroscopy detects lithium, constraining this L dwarf to be less than ∼2 Gyr old, but no Balmer emission is observed. The lowmore » measured projected rotation velocity ( v sin i < 6 km s{sup −1}) and lack of variability are very unusual compared to other brown dwarfs, and we argue that this substellar object is likely viewed pole-on. We detect quiescent (non-bursting) radio emission with the Very Large Array. Among radio-detected L and T dwarfs, it has the lowest observed L{sub ν} and the lowest v  sin  i . We discuss the implications of a pole-on detection for various proposed radio emission scenarios.« less

Tunable liquid microlens array driven by pyroelectric effect: full interferometric characterization

NASA Astrophysics Data System (ADS)

Miccio, Lisa; Grilli, Simonetta; Vespini, Veronica; Ferraro, Pietro

2008-09-01

Liquid lenses with adjustable focal length are of great interest in the field of microfluidic devices. They are, usually, realized by electrowetting effect after electrodes patterning on a hydrofobic substrate. Applications are possible in many fields ranging from commercial products such as digital cameras to biological cell sorting. We realized an open array of liquid lenses with adjustable focal length without electrode patterning. We used a z-cut Lithium Niobate crystal (LN) as substrate and few microliters of an oily substance to obtain the droplets array. The spontaneous polarization of LN crystals is reversed by the electric field poling process, thus enabling the realization of periodically poled LN (PPLN) crystals. The substrate consists of a two-dimensional square array of reversed domains with a period around 200 μm. Each domain presents an hexagonal geometry due to the crystal structure. PPLN is first covered by a thin and homogeneous layer of the above mentioned liquid and therefore its temperature is changed by means of a digitally controlled hot plate. During heating and cooling process there is a rearrangement of the liquid layer until it reaches the final topography. Lenses formation is due to the superficial tension changing at the liquid-solid interface by means of the pyroelectric effect. Such effect allows to create a two-dimensional lens pattern of tunable focal length without electrodes. The temporal evolution of both shape and focal length lenses are quantitatively measured by Digital Holographic Microscopy. Array imaging properties and quantitative analysis of the lenses features and aberrations are presented.

Late Quaternary variations in relative sea level due to glacial cycle polar wander

USGS Publications Warehouse

Bills, B.G.; James, T.S.

1996-01-01

Growth and decay of continental ice sheets can excite significant motion of the Earth's rotation pole and cause a complex spatio-temporal pattern of changes in relative sea level. These two effects have generally been considered separately, but may interact in important ways. In particular, a simple model of the melting of the Laurentide ice sheet causes a uniform eustatic sea level rise of 55 m, and also induces a motion of the rotation pole by 0.1 to 1 degree, depending on viscosity structure in the mantle. This motion produces a secular pole tide, which is a spherical harmonic degree 2, order 1 component of the relative sea level pattern, with peak-to-peak amplitude of 20 to 40 m. The maximum effect is along the great circle passing through the path of the pole and at latitudes of ??45??. This secular pole tide has been ignored in most previous attempts to estimate ice sheet loading history and mantle viscosity from global patterns of relative sea level change. It has a large influence along the East coast of North America and the West coast of South America, and significantly contributes to present day rates of relative sea level change.

Diffusion Entropy: A Potential Neuroimaging Biomarker of Bipolar Disorder in the Temporal Pole.

PubMed

Spuhler, Karl; Bartlett, Elizabeth; Ding, Jie; DeLorenzo, Christine; Parsey, Ramin; Huang, Chuan

2018-02-01

Despite much research, bipolar depression remains poorly understood, with no clinically useful biomarkers for its diagnosis. The paralimbic system has become a target for biomarker research, with paralimbic structural connectivity commonly reported to distinguish bipolar patients from controls in tractography-based diffusion MRI studies, despite inconsistent findings in voxel-based studies. The purpose of this analysis was to validate existing findings with traditional diffusion MRI metrics and investigate the utility of a novel diffusion MRI metric, entropy of diffusion, in the search for bipolar depression biomarkers. We performed group-level analysis on 9 un-medicated (6 medication-naïve; 3 medication-free for at least 33 days) bipolar patients in a major depressive episode and 9 matched healthy controls to compare: (1) average mean diffusivity (MD) and fractional anisotropy (FA) and; (2) MD and FA histogram entropy-a statistical measure of distribution homogeneity-in the amygdala, hippocampus, orbitofrontal cortex and temporal pole. We also conducted classification analyses with leave-one-out and separate testing dataset (N = 11) approaches. We did not observe statistically significant differences in average MD or FA between the groups in any region. However, in the temporal pole, we observed significantly lower MD entropy in bipolar patients; this finding suggests a regional difference in MD distributions in the absence of an average difference. This metric allowed us to accurately characterize bipolar patients from controls in leave-one-out (accuracy = 83%) and prediction (accuracy = 73%) analyses. This novel application of diffusion MRI yielded not only an interesting separation between bipolar patients and healthy controls, but also accurately classified bipolar patients from controls. © 2017 Wiley Periodicals, Inc.

Surface Temperatures on Titan During Northern Winter and Spring

NASA Technical Reports Server (NTRS)

Jennings, D. E.; Cottini, V.; Nixon, C. A.; Achterberg, R. K.; Flasar, F. M.; Kunde ,V. G.; Romani, P. N.; Samuelson, R. E.; Mamoutkine, A.; Gorius, N. J. P.;

Pollution Beat Explorers to South Pole

NASA Image and Video Library

2014-07-28

Norwegian explorer Roald Amundsen became the first man to reach the South Pole in December 1911. More than 100 years later, an international team of scientists that includes a NASA researcher has proven that air pollution from industrial activities arrived to the planet’s southern pole long before any human. Using data from 16 ice cores collected from widely spaced locations around the Antarctic continent, including the South Pole, a group led by Joe McConnell of the Desert Research Institute (DRI) in Reno, Nevada, created the most accurate and precise reconstruction to date of lead pollution over Earth’s southernmost continent. The new record, described in an article published today in the online edition of the Nature Publishing Group’s journal Scientific Reports, spans a 410-year period from 1600 to 2010. More here: 1.usa.gov/1oB4p9U NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Cavity-dumped femtosecond optical parametric oscillator based on periodically poled stoichiometric lithium tantalate

NASA Astrophysics Data System (ADS)

Yoon, E.; Joo, T.

2016-03-01

A synchronously pumped cavity-dumped femtosecond optical parametric oscillator (OPO) based on a periodically poled stoichiometric lithium tantalate (PPSLT) crystal is reported. The OPO runs in positive group velocity dispersion (GVD) mode to deliver high pulse energy at high repetition rate. It delivers pulse energy over 130 nJ up to 500 kHz and 70 nJ at 1 MHz of repetition rate at 1100 nm. Pulse duration is as short as 42 fs, and the OPO is tunable in the near infrared region from 1050 to 1200 nm. Dispersion property of the OPO was also explored. The cavity-dumped output carries a positive GVD, which can be compensated easily by an external prism pair, and large negative third order dispersion (TOD), which results in a pedestal in the pulse shape. Approaches to obtain clean pulse shape by reducing the large TOD are proposed.

Pediatric volleyball-related injuries treated in US emergency departments, 1990-2009.

PubMed

Pollard, Katherine A; Shields, Brenda J; Smith, Gary A

2011-09-01

This study describes the epidemiology of pediatric volleyball-related injuries treated in US hospital emergency departments. Data for children younger than 18 years obtained from the National Electronic Injury Surveillance System of the US Consumer Product Safety Commission from 1990 through 2009 were analyzed. An estimated 692 024 volleyball-related injuries to children younger than 18 years occurred during the study period. The annual number of injuries declined significantly by 23% during the study period; however, the annual injury rate remained unchanged, and the number of volleyball-related concussions/closed head injuries increased significantly. Upper (48%) and lower (39%) extremity injuries occurred most frequently, as did strains/sprains (54%). Contact with the net/pole was associated with concussions/closed head injury our findings indicate opportunities for making volleyball an even safer sport for children. Protective padding, complying with US volleyball standards, should cover all volleyball poles and protruding hardware to prevent impact-related injuries.

Multiple copies of orbital angular momentum states through second-harmonic generation in a two-dimensional periodically poled LiTaO{sub 3} crystal

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

Fang, Xinyuan; Wei, Dunzhao; Liu, Dongmei

We experimentally demonstrate multiple copies of optical orbital angular momentum (OAM) states through quasi-phase-matched (QPM) second-harmonic (SH) generation in a 2D periodically poled LiTaO{sub 3} (PPLT) crystal. Since the QPM condition is satisfied by involving different reciprocal vectors in the 2D PPLT crystal, collinear and noncollinear SH beams carrying OAMs of l{sub 2} are simultaneously generated by the input fundamental beam with an OAM of l{sub 1}. The OAM conservation law (i.e., l{sub 2} = 2l{sub 1}) holds well in the experiment, which can tolerate certain phase-mismatch between the interacting waves. Our results provide an efficient way to obtain multiple copies ofmore » the wavelength-converted OAM states, which can be used to enhance the capacity in optical communications.« less

Globally Averaged Atmospheric CFC-11 Concentrations: Monthly and Annual Data for the Period 1975-1992 (DB1010)

DOE Data Explorer

Khalil, M. A.K. [Oregon Graduate Institute of Science and Technology Portland, Oregon (USA); Rasmussen, R. A. [Oregon Graduate Institute of Science and Technology Portland, Oregon

1996-01-01

This data set presents globally averaged atmospheric concentrations of chlorofluorocarbon 11, known also as CFC-11 or F-11 (chemical name: trichlorofluoromethane; formula: CCl3F). The monthly global average data are derived from flask air samples collected at eight sites in six locations over the period August 1980-July 1992. The sites are Barrow (Alaska), Cape Meares (Oregon), Cape Kumukahi and Mauna Loa (Hawaii), Cape Matatula (American Samoa), Cape Grim (Tasmania), Palmer Station, and the South Pole (Antarctica). At each collection site, monthly averages were obtained from three flask samples collected every week. In addition to the monthly global averages available for 1980-992, this data set also contains annual global average data for 1975-1985. These annual global averages were derived from January measurements at the South Pole and in the Pacific Northwest of the United States (specifically, Washington state and the Oregon coast).

Lightcurves of nine asteroids, with pole and sense of rotation of 42 Isis

NASA Astrophysics Data System (ADS)

Denchev, P.; Magnusson, P.; Donchev, Z.

1998-02-01

The results of photometric observations of 9 asteroids collected from 1991 to 1997 are presented. The observations have been conducted at Belogradchik and Rozhen observatories, Bulgaria. For 42 Isis a spin pole determination has been performed: we derive a retrograde sense of rotation, a sidereal period of 0.5665417 ± 0.0000005 days and two solutions for the spin vector: ( P1: λ0 = 288° ± 5°, β0 = -16° ± 2°; P2: λ0 = 117° ± 8°, β0 = -5° ± 4°). The rotational period of 266 Aline is estimated to be 12.3±0.1 h. Composite lightcurves have been obtained for four objects (21 Lutetia, 24 Themis, 42 Isis and 266 Aline). Other lightcurves have been obtained for the asteroids 27 Euterpe, 38 Leda, 70 Panopaea, 173 Ino and 218 Bianca.

Ozone vertical profile changes over South Pole

NASA Technical Reports Server (NTRS)

Oltmans, S. J.; Hofmann, D. J.; Komhyr, W. D.; Lathrop, J. A.

1994-01-01

Important changes in the ozone vertical profile over South Pole, Antarctica have occurred both during the recent period of measurements, 1986-1991, and since an earlier set of soundings was carried out from 1967-1971. From the onset of the 'ozone hole' over Antarctica in the early 1980s, there has been a tendency for years with lower spring ozone amounts to alternate with years with somewhat higher (although still depleted) ozone amounts. Beginning in 1989 there have been three consecutive years of strong depletion although the timing of the breakdown of the vortex has varied from year to year. Comparison of the vertical profiles between the two periods of study reveals the dramatic decreases in the ozone amounts in the stratosphere between 15-21 km during the spring. In addition, it appears that summer values are also now much lower in this altitude region.

Broadband sum-frequency generation using d₃₃ in periodically poled LiNbO₃ thin film in the telecommunications band.

PubMed

Li, Guangzhen; Chen, Yuping; Jiang, Haowei; Chen, Xianfeng

2017-03-01

We demonstrate the first, to the best of our knowledge, type-0 broadband sum-frequency generation (SFG) based on single-crystal periodically poled LiNbO₃ (PPLN) thin film. The broad bandwidth property was largely tuned from mid-infrared region to the telecommunications band by engineering the thickness of PPLN from bulk crystal to nanoscale. It provides SFG a solution with both broadband and high efficiency by using the highest nonlinear coefficient d₃₃ instead of d₃₁ in type-I broadband SFG or second-harmonic generation. The measured 3 dB upconversion bandwidth is about 15.5 nm for a 4 cm long single crystal at 1530 nm wavelength. It can find applications in chip-scale spectroscopy, quantum information processing, LiNbO₃-thin-film-based microresonator and optical nonreciprocity devices, etc.

Agile multicasting based on cascaded χ(2) nonlinearities in a step-chirped periodically poled lithium niobate.

PubMed

Ahlawat, Meenu; Bostani, Ameneh; Tehranchi, Amirhossein; Kashyap, Raman

2013-08-01

We experimentally demonstrate the possibility of agile multicasting for wavelength division multiplexing (WDM) networks, of a single-channel to two and seven channels over the C band, also extendable to S and L bands. This is based on cascaded χ(2) nonlinear mixing processes, namely, second-harmonic generation (SHG)-sum-frequency generation (SFG) and difference-frequency generation (DFG) in a 20-mm-long step-chirped periodically poled lithium niobate crystal, specially designed and fabricated for a 28-nm-wide SH-SF bandwidth centered at around 1.55 μm. The multiple idlers are simultaneously tuned by detuning the pump wavelengths within the broad SH-SF bandwidth. By selectively tuning the pump wavelengths over less than 10 and 6 nm, respectively, multicasting into two and seven idlers is successfully achieved across ~70 WDM channels within the 50 GHz International Telecommunication Union grid spacing.

Mid-infrared trace gas detection using continuous-wave difference frequency generation in periodically poled RbTiOAsO4

NASA Technical Reports Server (NTRS)

Chen, W.; Mouret, G.; Boucher, D.; Tittel, F. K.

2001-01-01

A tunable mid-infrared continuous-wave (cw) spectroscopic source in the 3.4-4.5 micrometers region is reported, based on difference frequency generation (DFG) in a quasi-phase-matched periodically poled RbTiOAsO4 (PPRTA) crystal. DFG power levels of 10 microW were generated at approximately 4 micrometers in a 20-mm long PPRTA crystal by mixing two cw single-frequency Ti:Al2O3 lasers operating near 713 nm and 871 nm, respectively, using a laser pump power of 300 mW. A quasi-phase-matched infrared wavelength-tuning bandwidth (FWHM) of 12 cm-1 and a temperature tuning rate of 1.02 cm-1/degree C were achieved. Experimental details regarding the feasibility of trace gas detection based on absorption spectroscopy of CO2 in ambient air using this DFG radiation source are also described.

Active crystals on a sphere

NASA Astrophysics Data System (ADS)

Praetorius, Simon; Voigt, Axel; Wittkowski, Raphael; Löwen, Hartmut

2018-05-01

Two-dimensional crystals on curved manifolds exhibit nontrivial defect structures. Here we consider "active crystals" on a sphere, which are composed of self-propelled colloidal particles. Our work is based on a phase-field-crystal-type model that involves a density and a polarization field on the sphere. Depending on the strength of the self-propulsion, three different types of crystals are found: a static crystal, a self-spinning "vortex-vortex" crystal containing two vortical poles of the local velocity, and a self-translating "source-sink" crystal with a source pole where crystallization occurs and a sink pole where the active crystal melts. These different crystalline states as well as their defects are studied theoretically here and can in principle be confirmed in experiments.

A Meinardus Theorem with Multiple Singularities

NASA Astrophysics Data System (ADS)

Granovsky, Boris L.; Stark, Dudley

2012-09-01

Meinardus proved a general theorem about the asymptotics of the number of weighted partitions, when the Dirichlet generating function for weights has a single pole on the positive real axis. Continuing (Granovsky et al., Adv. Appl. Math. 41:307-328, 2008), we derive asymptotics for the numbers of three basic types of decomposable combinatorial structures (or, equivalently, ideal gas models in statistical mechanics) of size n, when their Dirichlet generating functions have multiple simple poles on the positive real axis. Examples to which our theorem applies include ones related to vector partitions and quantum field theory. Our asymptotic formula for the number of weighted partitions disproves the belief accepted in the physics literature that the main term in the asymptotics is determined by the rightmost pole.

A test of fixed and moving reference point control in posture.

PubMed

Lee, I-Chieh; Pacheco, Matheus M; Newell, Karl M

2017-01-01

This study investigated two contrasting assumptions of the regulation of posture: namely, fixed and moving reference point control. These assumptions were tested in terms of time-dependent structure and data distribution properties when stability is manipulated. Fifteen male participants performed a tightrope simulated balance task that is, maintaining a tandem stance while holding a pole. Pole length (and mass) and the standing support surface (fixed surface/balance board) were manipulated so as to mechanically change the balance stability. The mean and standard deviation (SD) of COP length were reduced with pole length increment but only in the balance board surface condition. Also, the SampEn was lower with greater pole length for the balance board but not the fixed surface. More than one peak was present in the distribution of COP in the majority of trials. Collectively, the findings provide evidence for a moving reference point in the maintenance of postural stability for quiet standing. Copyright © 2016 Elsevier B.V. All rights reserved.

A Micro-Resonant Gas Sensor with Nanometer Clearance between the Pole Plates

PubMed Central

Xu, Lizhong

2018-01-01

In micro-resonant gas sensors, the capacitive detection is widely used because of its simple structure. However, its shortcoming is a weak signal output caused by a small capacitance change. Here, we reduced the initial clearance between the pole plates to the nanometer level, and increased the capacitance between the pole plates and its change during resonator vibration. We propose a fabricating process of the micro-resonant gas sensor by which the initial clearance between the pole plates is reduced to the nanometer level and a micro-resonant gas sensor with 200 nm initial clearance is fabricated. With this sensor, the resonant frequency shifts were measured when they were exposed to several different vapors, and high detection accuracies were obtained. The detection accuracy with respect to ethanol vapor was 0.4 ppm per Hz shift, and the detection accuracy with respect to hydrogen and ammonias vapors was 3 ppm and 0.5 ppm per Hz shift, respectively. PMID:29373546

A Micro-Resonant Gas Sensor with Nanometer Clearance between the Pole Plates.

PubMed

Fu, Xiaorui; Xu, Lizhong

2018-01-26

In micro-resonant gas sensors, the capacitive detection is widely used because of its simple structure. However, its shortcoming is a weak signal output caused by a small capacitance change. Here, we reduced the initial clearance between the pole plates to the nanometer level, and increased the capacitance between the pole plates and its change during resonator vibration. We propose a fabricating process of the micro-resonant gas sensor by which the initial clearance between the pole plates is reduced to the nanometer level and a micro-resonant gas sensor with 200 nm initial clearance is fabricated. With this sensor, the resonant frequency shifts were measured when they were exposed to several different vapors, and high detection accuracies were obtained. The detection accuracy with respect to ethanol vapor was 0.4 ppm per Hz shift, and the detection accuracy with respect to hydrogen and ammonias vapors was 3 ppm and 0.5 ppm per Hz shift, respectively.

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

Husain, Tausif; Hasan, Iftekhar; Sozer, Yilmaz

This paper presents the design considerations of a double-sided transverse flux machine (TFM) for direct-drive wind turbine applications. The TFM has a modular structure with quasi-U stator cores and ring windings. The rotor is constructed with ferrite magnets in a flux-concentrating arrangement to achieve high air gap flux density. The design considerations for this TFM with respect to initial sizing, pole number selection, key design ratios, and pole shaping are presented in this paper. Pole number selection is critical in the design process of a TFM because it affects both the torque density and power factor under fixed magnetic andmore » changing electrical loading. Several key design ratios are introduced to facilitate the design procedure. The effect of pole shaping on back-emf and inductance is also analyzed. These investigations provide guidance toward the required design of a TFM for direct-drive applications. The analyses are carried out using analytical and three-dimensional finite element analysis. A prototype is under construction for experimental verification.« less

Holocene geomagnetic secular variation recorded by volcanic deposits at Mount St. Helens, Washington

USGS Publications Warehouse

Hagstrum, J.T.; Hoblitt, R.P.; Gardner, C.A.; Gray, T.E.

2002-01-01

A compilation of paleomagnetic data from volcanic deposits of Mount St. Helens is presented in this report. The database is used to determine signature paleomagnetic directions of products from its Holocene eruptive events, to assign sampled units to their proper eruptive period, and to begin the assembly of a much larger database of paleomagnetic directions from Holocene volcanic rocks in western North America. The paleomagnetic results from Mount St. Helens are mostly of high quality, and generally agree with the division of its volcanic deposits into eruptive episodes based on previous geologic mapping and radiocarbon dates. The Muddy River andesite's paleomagnetic direction, however, indicates that it is more likely part of the Pine Creek eruptive period rather than the Castle Creek period. In addition, the Two-Fingers andesite flow is more likely part of the Middle Kalama eruptive period and not part of the Goat Rocks period. The paleomagnetic data from Mount St. Helens and Mount Hood document variation in the geomagnetic field's pole position over the last ~2,500 years. A distinct feature of the new paleosecular variation (PSV) record, similar to the Fish Lake record (Oregon), indicates a sudden change from rapid clockwise movement of the pole about the Earth's spin axis to relatively slow counterclockwise movement at ???800 to 900 years B.P.

McDonald 2.1-m and CRTS Photometry of Eclipsing Polars

NASA Astrophysics Data System (ADS)

Wells, Natalie; Mason, Paul

2018-01-01

We present broadband optical photometry of five polars made using the 2.1-m telescope of McDonald Observatory. Four of the polars are eclipsing (EP Dra, FL Cet, V2301 Oph, and a Catalina Sky Survey (CSS) polar candidate). In addition, a pre-polar (MQ Dra) was observed. Typical integration times were 1-3 seconds with no dead time. At this time resolution, eclipse structure can be seen in both one- and two-pole accretors. McDonald 2.1-m data over several years is phased together with CSS photometry covering up to 7 years, in search of indications of period variation. Combining the high-resolution, high-speed photometry obtained using the ProEm camera on the McDonald 2.1-m with the sparse, but high-quality multi-year baseline photometry of the CSS places strong constraints on the time variability of the eclipse periods in these binary systems. In most cases, eclipse variations do not perfectly fit a linear ephemeris. We investigate the source of variations using standard O-C diagram techniques and period search algorithms.

Constraints on Titan's rotation from Cassini mission radar data

NASA Astrophysics Data System (ADS)

Bills, Bruce; Stiles, Bryan W.; Hayes, Alexander

2015-05-01

We present results of a new analysis of the rotational kinematics of Titan, as constrained by Cassini radar data, extending over the entire currently available set of flyby encounters. Our analysis provides a good constraint on the current orientation of the spin pole, but does not have sufficient accuracy and duration to clearly see the expected spin pole precession. In contrast, we do clearly see temporal variations in the spin rate, which are driven by gravitational torques which attempt to keep the prime meridian oriented toward Saturn.Titan is a synchronous rotator. At lowest order, that means that the rotational and orbital motions are synchronized. At the level of accuracy required to fit the Cassini radar data, we can see that synchronous rotation and uniform rotation are not quite the same thing. Our best fitting model has a fixed pole, and a rotation rate which varies with time, so as to keep Titan's prime meridian oriented towards Saturn, as the orbit varies.A gravitational torque on the tri-axial figure of Titan attempts to keep the axis of least inertia oriented toward Saturn. The main effect is to synchronize the orbit and rotation periods, as seen in inertial space. The response of the rotation angle, to periodic changes in orbital mean longitude, is modeled as a damped, forced harmonic oscillator. This acts as a low-pass filter. The rotation angle accurately tracks orbital variations at periods longer than the free libration period, but is unable to follow higher frequency variations.The mean longitude of Titan's orbit varies on a wide range of time scales. The largest variations are at Saturn's orbital period (29.46 years), and are due to solar torques. There are also variations at periods of 640 and 5800 days, due to resonant interaction with Hyperion.For a rigid body, with moments of inertia estimated from observed gravity, the free libration period for Titan would be 850 days. The best fit to the radar data is obtained with a libration period of 645 days, and a damping time of 1000 years.The principal deviation of Titan's rotation from uniform angular rate, as seen in the Cassini radar data, is a periodic signal resonantly forced by Hyperion.

Emotional intelligence moderates the relationship between regional gray matter volume in the bilateral temporal pole and critical thinking disposition.

PubMed

Yao, Xiaonan; Yuan, Shuge; Yang, Wenjing; Chen, Qunlin; Wei, Dongtao; Hou, Yuling; Zhang, Lijie; Qiu, Jiang; Yang, Dong

2018-04-01

Critical thinking enables people to form sound beliefs and provides a basis for emotional life. Research has indicated that individuals with better critical thinking disposition can better recognize and regulate their emotions, though the neuroanatomical mechanisms involved in this process remain to be elucidated. Further, the influence of emotional intelligence on the relationship between brain structure and critical thinking disposition has not been examined. The present study utilized voxel-based morphometry (VBM) to investigate the neural structures underlying critical thinking disposition in a large sample of college students (N = 296). Regional gray matter volume (rGMV) in the bilateral temporal pole, which reflects an individual's ability to process social and emotional information, was negatively correlated with critical thinking disposition. In addition, rGMV in bilateral para hippocampal regions -regions involved in contextual association/emotional regulation-exhibited negative correlation with critical thinking disposition. Further analysis revealed that emotional intelligence moderated the relationship between rGMV of the temporal pole and critical thinking disposition. Specifically, critical thinking disposition was associated with decreased GMV of the temporal pole for individuals who have relatively higher emotional intelligence rather than lower emotional intelligence. The results of the present study indicate that people who have higher emotional intelligence exhibit more effective and automatic processing of emotional information and tend to be strong critical thinkers.

Seasonal Evolution of Titan's South Pole 220 cm-1 Cloud

NASA Astrophysics Data System (ADS)

Jennings, Donald

2016-06-01

A cloud of ices that had been seen only in Titan's north during winter began to emerge at the south pole in 2012. Discovered by Voyager IRIS as an emission feature at 220 cm-1, the cloud has been studied extensively in both the north and south by Cassini CIRS. The spectral feature acts as a tracer of the seasonal changes at Titan's poles, relating to evolving composition, temperature structure and dynamics. Although candidates have been proposed, the chemical makeup of the cloud has never been identified. The cloud is composed of condensates derived from gases created at high altitude and transported to the cold, shadowed pole. In the north the cloud has diminished gradually over the Cassini mission as Titan has transitioned from winter to spring. The southern cloud, on the other hand, grew rapidly after 2012. By late 2014 it had developed a complex ring structure that was confined to latitudes poleward of 70°S within the deep temperature well that had formed at the south pole [1]. The location of the cloud coincides in latitude with the HCN cloud reported by ISS and VIMS [2,3]. CIRS also saw enhanced gas emissions at those latitudes [4]. When it first formed, the cloud was abundant at altitudes as high as 250 km, while later it was found mostly at 100-150 km, suggesting that the material that had been deposited from above had gathered at the lower altitudes. Radiance from the southern cloud increased until mid-2015 and since then has decreased. The cloud may be transitioning to the more uniform hood morphology familiar in the north. Taking the north and south together, by the end of the Cassini mission in 2017 we will have observed almost an entire seasonal cycle of the ice cloud.

Technological and economical analysis of salient pole and permanent magnet synchronous machines designed for wind turbines

NASA Astrophysics Data System (ADS)

Gündoğdu, Tayfun; Kömürgöz, Güven

2012-08-01

Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality. The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted.

State of the Venus Atmosphere from Venus Express at the time of MESSENGER FLy- By

NASA Astrophysics Data System (ADS)

Limaye, S. S.; Markiewicz, W. J.; Titov, D.; Piccione, G.; Baines, K. H.; Robinson, M.

2007-12-01

The Venus Monitoring Camera (VMC) and the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instruments on Venus Express spacecraft have been observing Venus since orbit insertion in April 2006. The state of the atmosphere in 2006 was in the form of a hemispheric vortex centered over the south pole, and presumably, another one in the northen hemisphere. The VMC and VIRTIS data have been used to determine cloud motions as well as the structure and organization of the atmospheric circulation from the the data collected since June 2006. In June 2007, the MESSENGER spacecraft flew-past Venus and also observed Venus on approach and departure from Venus. We report on the atmosphere of Venus as it appeared during this period.

Current studies and improvements on a single frequency blue source generated by second harmonic from IR

NASA Astrophysics Data System (ADS)

Khademian, Ali; Jampani, Sai Lakshman; Truscott, Matthew; Jayaraj, Anooja; Shiner, David

2017-04-01

We have reported 81.5% efficiency in generating 500 mW of blue at 486 nm by second harmonic generation (SHG) from the IR, using a periodically poled Lithium Tantalate (PPSLT) crystal. Initially a total cavity loss of 0.65% was observed. We developed techniques for careful measurement of individual losses such as scattering and absorption in the crystal and mirrors, polarization misalignment caused by the crystal and back reflection from the periodically poled boundaries of crystal. We have replaced the crystal with a tilted periodically poled crystal. This eliminated the reflection loss, but scattering in the crystal, we speculate from the MgO doping, is still causing enough feedback to destabilize the IR source. We are also replacing cavity mirrors with ultra-low loss sputtered mirrors to minimize their contribution to loss. Crystal lifetime at different blue power levels is being investigated. In our setup a mixed signal processer (MSP) is used for cavity locking and temperature stabilizing. Once MSP is programed by a computer interface, it can be installed inside the cavity housing, making the laser source standalone and self-sufficient. We have been able to stabilize and lock the laser cavity length, the temperature of the IR laser source, the temperature of fiber Bragg grating (FBG), and the temperature of the nonlinear crystal using the MSP, matching the performance of high end commercial temperature controllers and lock-in amplifiers. Our recent progress and improvements will be presented. This work is supported by NSF award 1404498.

Periodicity in Attachment Organelle Revealed by Electron Cryotomography Suggests Conformational Changes in Gliding Mechanism of Mycoplasma pneumoniae

PubMed Central

Kawamoto, Akihiro; Matsuo, Lisa; Kato, Takayuki; Yamamoto, Hiroki

2016-01-01

ABSTRACT Mycoplasma pneumoniae, a pathogenic bacterium, glides on host surfaces using a unique mechanism. It forms an attachment organelle at a cell pole as a protrusion comprised of knoblike surface structures and an internal core. Here, we analyzed the three-dimensional structure of the organelle in detail by electron cryotomography. On the surface, knoblike particles formed a two-dimensional array, albeit with limited regularity. Analyses using a nonbinding mutant and an antibody showed that the knoblike particles correspond to a naplike structure that has been observed by negative-staining electron microscopy and is likely to be formed as a complex of P1 adhesin, the key protein for binding and gliding. The paired thin and thick plates feature a rigid hexagonal lattice and striations with highly variable repeat distances, respectively. The combination of variable and invariant structures in the internal core and the P1 adhesin array on the surface suggest a model in which axial extension and compression of the thick plate along a rigid thin plate is coupled with attachment to and detachment from the substrate during gliding. PMID:27073090

Photogeological analysis of Europan tectonic features

NASA Technical Reports Server (NTRS)

Tufts, B. R.

1993-01-01

Preliminary photogeological analyses of the Pelorus Linea and Sidon Flexus regions of Europa were conducted to explore the proposal by Schenk that lateral motion of crustal blocks has occurred in a 'rift zone' including possible strike-slip, tension fracturing, and geometric plate rotation about an Euler pole. These analyses revealed features interpreted as tensional structures and block rotation in a strike-slip regime consistent with the Schenk hypotheses and implied the presence of at least two stages of crustal deformation consistent with a chronology developed by Lucchitta. Confirmation of regional scale Euler pole rotation was ambiguous, however. Up to 80 kilometers of possible extension was identified in the rift zone; to accommodate this, 'cryosubduction' is speculatively proposed as a mechanism for recycling Europan 'ice lithosphere'. The cumulative width of wedge-shaped bands included in the rift zone was measured and plotted versus distance from the inferred rotation pole. Three sharp decreases in the total width were noted. These occur roughly where certain triple bands cross the rift zone suggesting that the bands are structural features that predate and influence the zone. While the curve hints at one or more sinusoidal relationships consistent with rotation geometry, given the low photographic resolution and the preliminary nature of this examination the question of whether the observations represent coherent regional rotation modified by crosscutting structures or instead imply independent local rotations separated by these structures is unanswered by this analysis.

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

DOE PAGES

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.; ...

2016-11-01

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

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

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Waveguide Harmonic Generator for the SIM

NASA Technical Reports Server (NTRS)

Chang, Daniel; Poberezhskiy, Ilya; Mulder, Jerry

2008-01-01

A second-harmonic generator (SHG) serves as the source of the visible laser beam in an onboard calibration scheme for NASA's planned Space Interferometry Mission (SIM), which requires an infrared laser beam and a visible laser beam coherent with the infrared laser beam. The SHG includes quasi-phase-matched waveguides made of MgO-doped, periodically poled lithium niobate, pigtailed with polarization- maintaining optical fibers. Frequency doubling by use of such waveguides affords the required combination of coherence and sufficient conversion efficiency for the intended application. The spatial period of the poling is designed to obtain quasi-phase- matching at a nominal middle excitation wavelength of 1,319.28 nm. The SHG is designed to operate at a warm bias (ambient temperature between 20 and 25 C) that would be maintained in its cooler environment by use of electric heaters; the heater power would be adjusted to regulate the temperature precisely and thereby maintain the required precision of the spatial period. At the state of development at the time of this reporting, the SHG had been packaged and subjected to most of its planned space-qualification tests.

Task relevance modulates the cortical representation of feature conjunctions in the target template.

PubMed

Reeder, Reshanne R; Hanke, Michael; Pollmann, Stefan

2017-07-03

Little is known about the cortical regions involved in representing task-related content in preparation for visual task performance. Here we used representational similarity analysis (RSA) to investigate the BOLD response pattern similarity between task relevant and task irrelevant feature dimensions during conjunction viewing and target template maintenance prior to visual search. Subjects were cued to search for a spatial frequency (SF) or orientation of a Gabor grating and we measured BOLD signal during cue and delay periods before the onset of a search display. RSA of delay period activity revealed that widespread regions in frontal, posterior parietal, and occipitotemporal cortices showed general representational differences between task relevant and task irrelevant dimensions (e.g., orientation vs. SF). In contrast, RSA of cue period activity revealed sensory-related representational differences between cue images (regardless of task) at the occipital pole and additionally in the frontal pole. Our data show that task and sensory information are represented differently during viewing and during target template maintenance, and that task relevance modulates the representation of visual information across the cortex.

Use of wood in buildings and bridges

Treesearch

Russell C. Moody; Anton TenWolde

1999-01-01

In North America, most housing and commercial structures built prior to the 20th century used wood as the major structural material. The abundant wood resource formed the basic structure for most houses, commercial buildings, bridges, and utility poles. Today, houses and many light commercial and industrial buildings are made using modern wood structural materials....

Paléomagnétisme de l'unité inférieure autunienne de la formation rouge du bassin d'Abadla (Algérie)

NASA Astrophysics Data System (ADS)

Bouabdallah, Hamza; Mérabet, Nacer; Henry, Bernard

1998-07-01

A new palaeomagnetic pole situated at 29.1°S and 57.8°E has been obtained in the lower unit, of Autunian age ( Doubinger and Fabre, 1983) of the Abadla redbeds formation. The proximity of this pole with that of Morel et al. (1981), determined in the azoic and undated upper unit of the same formation, suggests an Autunian age for this upper unit. Thus, the subsidence of the Abadla basin and the deposition of the whole series occurred within a period no longer than 20-25 My.

Thermal stability and structural characterization of organic/inorganic hybrid nonlinear optical material containing a two-dimensional chromophore.

PubMed

Chang, Po-Hsun; Tsai, Hsieh-Chih; Chen, Yu-Ren; Chen, Jian-Yu; Hsiue, Ging-Ho

2008-10-21

In this study, two nonlinear optic hybrid materials with different dimensional alkoxysilane dyes were prepared and characterized. One NLO silane (Cz2PhSO 2OH- TES), a two-dimensional structure based on carbazole, had a larger rotational volume than the other (DR19-TES). Second harmonic ( d 33) analysis verified there is an optimum heating process for the best poling efficiency. The maximum d 33 value of NLO hybrid film containing Cz2PhSO 2OH was obtained for 10.7 pm/V after precuring at 150 degrees C for 3 h and poling at 210 degrees C for 60 min. The solid-state (29)Si NMR spectrum shows that the main factor influencing poling efficiency and thermal stability was cross-linking degree of NLO silane, but not that of TMOS. In particular, the two-dimensional sol-gel system has a greater dynamic and temporary stability than the one-dimensional system due to Cz2PhSO 2OH-TES requiring a larger volume to rotate in the hybrid matrix after cross-linking.

Optimal Robust Motion Controller Design Using Multiobjective Genetic Algorithm

PubMed Central

Svečko, Rajko

2014-01-01

This paper describes the use of a multiobjective genetic algorithm for robust motion controller design. Motion controller structure is based on a disturbance observer in an RIC framework. The RIC approach is presented in the form with internal and external feedback loops, in which an internal disturbance rejection controller and an external performance controller must be synthesised. This paper involves novel objectives for robustness and performance assessments for such an approach. Objective functions for the robustness property of RIC are based on simple even polynomials with nonnegativity conditions. Regional pole placement method is presented with the aims of controllers' structures simplification and their additional arbitrary selection. Regional pole placement involves arbitrary selection of central polynomials for both loops, with additional admissible region of the optimized pole location. Polynomial deviation between selected and optimized polynomials is measured with derived performance objective functions. A multiobjective function is composed of different unrelated criteria such as robust stability, controllers' stability, and time-performance indexes of closed loops. The design of controllers and multiobjective optimization procedure involve a set of the objectives, which are optimized simultaneously with a genetic algorithm—differential evolution. PMID:24987749

Modern methods of experimental construction of texture complete direct pole figures by using X-ray data

NASA Astrophysics Data System (ADS)

Isaenkova, M.; Perlovich, Yu; Fesenko, V.

2016-04-01

Currently used methods for constructing texture complete direct pole figure (CDPF) based on the results of X-ray diffractometric measurements were considered with respect to the products of Zr-based alloys and, in particular, used in a nuclear reactor cladding tubes, for which the accuracy of determination of integral texture parameters is of the especial importance. The main attention was devoted to technical issues which are solved by means of computer processing of large arrays of obtained experimental data. Among considered questions there are amendments of the defocusing, techniques for constructing of complete direct pole figures and determination of integral textural parameters. The methods of reconstruction of complete direct pole figures by partial direct pole figures recorded up to tilt angles of sample ψ=70-80°: the method of extrapolation of data to an uninvestigated region of the stereographic projection, and the method of "sewing" of partial pole figures measured for three mutually perpendicular plane sections of the product. The limits of applicability of these methods, depending on the shape of the test product and the degree of inhomogeneity of the layer-by-layer texture, were revealed. On the basis of a large number of experimental data, the accuracy of the integral parameters used for calculation of the physical and mechanical properties of metals with a hexagonal crystal structure was found to be equal to 0.02, when taking into account the texture heterogeneity of regular products from Zr-based alloys.

On the effect of polarization direction on the converse magnetoelectric response of multiferroic composite rings

NASA Astrophysics Data System (ADS)

Youssef, George; Lopez, Mario; Newacheck, Scott

2017-03-01

The application domain of composite multiferroic materials with magnetoelectric coupling has been widening on the nano-, micro- and macro-scales. Generally, a composite multiferroic material consists of two, or more, layers of a piezoelectric material and a magnetostrictive material. In turn, the proliferation of multiferroics in more applications is accompanied by a keen focus on understanding the effect of material phases, geometry, bonding interface and arrangement of phases by performing theoretical, numerical and experimental studies to fundamentally elucidate the response. In this experimental study, a focus is given to exploit the effect of the polarization direction of the piezoelectric phase on the overall converse magnetoelectric (CME) response of a composite concentric PZT/Terfenol-D structure. Specifically, radially and axially polarized PZT rings were concentrically bonded to the outer surface of two Terfenol-D rings, respectively. It was found that the maximum, near resonance, CME coefficient of the axially-poled configuration is 443 mG V-1 when tested at 34 kHz, 80 kV m-1 electric field and 784 Oe bias magnetic field. On the other hand, the near resonance CME value for the radially-poled configuration remained nearly constant at 281.9 ± 5.3 mG V-1 between bias magnetic fields of 532 Oe and 1524 Oe at AC electric field of 80 kV m-1 with a frequency of 36 kHz. Interestingly, the CME coefficient of radially-poled composite structure exhibits a saturation behavior, while the CME coefficient for axially-poled structure is distinguished by a single peak. The difference in the response is attributed to the amount strain transduction due to the polarization direction.

A Scapholunate Ligament-Sparing Technique Utilizing the Medial Femoral Condyle Corticocancellous Free Flap to Reconstruct Scaphoid Nonunions With Proximal Pole Avascular Necrosis.

PubMed

Kazmers, Nikolas H; Thibaudeau, Stephanie; Levin, L Scott

2016-09-01

This article demonstrates a technique for the treatment of scaphoid fracture waist and proximal pole nonunions with avascular necrosis using a free vascularized medial femoral condyle flap. We present our surgical technique and representative case examples in which the scapholunate ligament, a key structure required to preserve carpal kinematics, is spared. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

A singular finite element technique for calculating continuum damping of Alfvén eigenmodes

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

Bowden, G. W.; Hole, M. J.

2015-02-15

Damping due to continuum resonances can be calculated using dissipation-less ideal magnetohydrodynamics provided that the poles due to these resonances are properly treated. We describe a singular finite element technique for calculating the continuum damping of Alfvén waves. A Frobenius expansion is used to determine appropriate finite element basis functions on an inner region surrounding a pole due to the continuum resonance. The location of the pole due to the continuum resonance and mode frequency is calculated iteratively using a Galerkin method. This method is used to find the complex frequency and mode structure of a toroidicity-induced Alfvén eigenmode inmore » a large aspect ratio circular tokamak and is shown to agree closely with a complex contour technique.« less

Protection Method of Biological Lightning Safety around Power Grid Based on Grounding Electrode Structure

NASA Astrophysics Data System (ADS)

Sixiang, Chen; Daopin, Chen; Ming, Zhang; Xiao, Huang; Jian, He; Zhijie, He

2017-05-01

Aimed at the actual situation of fish death in fish ponds near the power transmission line towers after the thunderstorm happened in Guangdong Province in China, this paper studied the influence of the ground current on fish in the pond. Firstly, This paper studied the current density of the fish without protection. On this basis, paper studied the horizontal pole with full-shielded, the vertical pole with half-shielded, the horizontal pole with extension three kinds of protective measures and effects. Finally an effective protection scheme was put forward according to the engineering practice. The results can provide some engineering guidance and quantitative basis for the design and modification of grounding devices when the tower is adjacent to the fish ponds in southern China.

Evidence for mass loss at polar latitudes in the Be stars Omega Orionis and 66 Ophiuchi

NASA Technical Reports Server (NTRS)

Peters, G. J.

1982-01-01

IUE observations of the pole-on Be stars Omega Ori and 66 Oph have revealed the unexpected presence of high velocity (-250 to -850 km/sec), relatively narrow (about 1 A) absorption components to the resonance lines of C IV, Si IV, and Si III. The C IV features show structure indicative of multiple shells or clouds. If Omega Ori and 66 Oph are indeed viewed pole-on, then these observations suggest that substantial matter is being ejected from the polar regions of these stars. The nature of these unusual high velocity features, which were not observed in other pole-on Be stars considered in the program, and the column densities and mass loss rates implied by them are discussed in this Letter.

The South Pole Telescope: Unraveling the Mystery of Dark Energy

NASA Astrophysics Data System (ADS)

Reichardt, Christian L.; de Haan, Tijmen; Bleem, Lindsey E.

2016-07-01

The South Pole Telescope (SPT) is a 10-meter telescope designed to survey the millimeter-wave sky, taking advantage of the exceptional observing conditions at the Amundsen-Scott South Pole Station. The telescope and its ground-breaking 960-element bolometric camera finished surveying 2500 square degrees at 95. 150, and 220 GHz in November 2011. We have discovered hundreds of galaxy clusters in the SPT-SZ survey through the Sunyaev-Zel’dovich (SZ) effect. The formation of galaxy clusters the largest bound objects in the universe is highly sensitive to dark energy and the history of structure formation. I will discuss the cosmological constraints from the SPT-SZ galaxy cluster sample as well as future prospects with the soon to-be-installed SPT-3G camera.

Infrared Signal Detection by Upconversion Technique

NASA Technical Reports Server (NTRS)

Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William E.

2014-01-01

We demonstrated up-conversion assisted detection of a 2.05-micron signal by using a bulk periodically poled Lithium niobate crystal. The 94% intrinsic up-conversion efficiency and 22.58% overall detection efficiency at pW level of 2.05-micron was achieved.

Egg structure and ultrastructure of Paterdecolyus yanbarensis (Insecta, Orthoptera, Anostostomatidae, Anabropsinae).

PubMed

Mashimo, Yuta; Fukui, Makiko; Machida, Ryuichiro

2016-11-01

The egg structure of Paterdecolyus yanbarensis was examined using light, scanning electron and transmission electron microscopy. The egg surface shows a distinct honeycomb pattern formed by exochorionic ridges. Several micropyles are clustered on the ventral side of the egg. The egg membrane is composed of an exochorion penetrated with numerous aeropyles, an endochorion, and an extremely thin vitelline membrane. The endochorion is thickened at the posterior egg pole, probably associated with water absorption. A comparison of egg structure among Orthoptera revealed that the micropylar distribution pattern is conserved in Ensifera and Caelifera and might be regarded as a groundplan feature for each group; in Ensifera, multiple micropyles are clustered on the ventral side of the egg, whereas in Caelifera, micropyles are arranged circularly around the posterior pole of the egg. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pluto and Triton: Interactions Between Volatiles and Dynamics

NASA Astrophysics Data System (ADS)

Rubincam, D. P.

2001-01-01

Volatiles moving across the surfaces of Pluto and Triton can give rise to interesting dynamical consequences. Conversely, measurement of dynamical states can help constrain the movement of volatiles and interior structure of both bodies. Polar wander may theoretically occur on both Triton and Pluto. Triton's obliquity is low, so that the equatorial regions receive more insolation than the poles. Hence there is a tendency for nitrogen ice to sublime at the equator and condense at the poles, creating polar caps. If the nitrogen supply is large enough, then these caps could move in approximately 105 years the global equivalent of 200 m of ice to the poles. At this point the equatorial moment of inertia becomes larger than the moment of inertia measured about the rotation axis, so that Triton overbalances and becomes dynamically unstable. The satellite then undergoes polar wander, restoring stability when the new equator contains the excess matter. Hence the pole may be continually wandering. Neptune raises a permanent tidal bulge on Triton, so that the satellite's surface is elongated like a football, with the long axis pointing at Neptune. This is expected to be the axis about which the pole wanders. Volatile migration would resurface the satellite to some depth and wandering would disturb leading side/trailing side crater statistics. Additional information is contained in the original extended abstract.

Brain hemodynamic activity during viewing and re-viewing of comedy movies explained by experienced humor

PubMed Central

Jääskeläinen, Iiro P.; Pajula, Juha; Tohka, Jussi; Lee, Hsin-Ju; Kuo, Wen-Jui; Lin, Fa-Hsuan

2016-01-01

Humor is crucial in human social interactions. To study the underlying neural processes, three comedy clips were shown twice to 20 volunteers during functional magnetic resonance imaging (fMRI). Inter-subject similarities in humor ratings, obtained immediately after fMRI, explained inter-subject correlation of hemodynamic activity in right frontal pole and in a number of other brain regions. General linear model analysis also indicated activity in right frontal pole, as well as in additional cortical areas and subcortically in striatum, explained by humorousness. The association of the right frontal pole with experienced humorousness is a novel finding, which might be related to humor unfolding over longer time scales in the movie clips. Specifically, frontal pole has been shown to exhibit longer temporal receptive windows than, e.g., sensory areas, which might have enabled processing of humor in the clips based on holding information and reinterpreting that in light of new information several (even tens of) seconds later. As another novel finding, medial and lateral prefrontal areas, frontal pole, posterior-inferior temporal areas, posterior parietal areas, posterior cingulate, striatal structures and amygdala showed reduced activity upon re-viewing of the clips, suggesting involvement in processing of humor related to novelty of the comedic events. PMID:27323928

Nonlinear Talbot Effect and Its Applications

NASA Astrophysics Data System (ADS)

Yang, Zhening

2018-03-01

Talbot effect, a lenless self-imaging phenomenon, was first discovered in 1836 by H.F. Talbot. The conventional Talbott effect has been studied for over a hundred years. Recently, the rapid development of optical superlattices has brought a great breakthrough in Talbot effect research. A nonlinear self-imaging phenomenon was found in the periodically poled LiTaO3 (PPLT) crystals. [1][2][3] This nonlinear Talbot effect has applications not only in optics but also in many other fields. For example, the phenomenon is realized by frequency-doubled beams, which offers people a new way to enhance the spatial resolution of the self-images of periodic objects. And by observing the self-image of the second harmonic (SH) field on the sample surface, people can detect the domain structure in the crystal without damaging the sample. Throughout this review paper, an overview of nonlinear Talbot effect and two applications of this phenomenon is presented. Breakthroughs like achieving a super-focused spot and realizing an acousto-optic tunable SH Talbot illuminator will be introduced as well.

Volatile Transport in Pluto's Super Seasons

NASA Astrophysics Data System (ADS)

Earle, Alissa M.; Binzel, Richard; Young, Leslie; Stern, S. Alan; Olkin, Catherine B.; Ennico, Kimberly; Moore, Jeffrey M.; Weaver, Harold A.; NASA New Horizons Composition Team, The NASA New Horizons GGI Team

2016-10-01

The data returned from NASA's New Horizons' reconnaissance of the Pluto system shows striking albedo variations from polar to equatorial latitudes as well as sharp boundaries for longitudinal variations. Pluto has a high obliquity (currently around 119 degrees) which varies by more than 23 degrees (between roughly 103 and 127 degrees) over a period of less than 3 million years. These obliquity properties, combined with Pluto's orbital regression in longitude of perihelion (360 degrees over 3.7 million years), create epochs of "Super Seasons" on Pluto. A "Super Season" occurs, for example, when Pluto happens to be pole-on towards the Sun at the same time as perihelion. In such a case, one pole experiences a short, intense summer (relative to its long-term average) followed by a longer than average period of winter darkness. By complement, the other pole experiences a much longer, but less intense summer and short winter season. We explore the relationship between albedo variations and volatile transport for the current epoch as well as historical epochs during which Pluto experienced these "Super Seasons". Our investigation suggests Pluto's orbit creates the potential for runaway albedo variations, particularly in the equatorial region, which would create and support stark longitudinal contrasts like the ones we see between the informally named Tombaugh and Cthulhu Regios.This work was supported by the NASA New Horizons mission.

Ionospheric signatures of cusp latitude Pc 3 pulsations

NASA Technical Reports Server (NTRS)

Engebretson, M. J.; Anderson, B. J.; Cahill, L. J., Jr.; Arnoldy, R. L.; Rosenberg, T. J.

1990-01-01

Search coil magnetometer, riometer, photometer, and ELF-VLF receiver data obtained at South Pole Station and McMurdo, Antarctica during selected days in March and April 1986 are compared. Narrow-band magnetic pulsations in the Pc 3 period range are observed simultaneously at both stations in the dayside sector during times of low IMF cone angle, but are considerably stronger at South Pole, which is located at a latitude near the nominal foot point of the dayside cusp/cleft region. Pulsations in auroral light at 427.8 nm wavelength are often observed with magnetic pulsations at South Pole, but such optical pulsations are not observed at McMurdo. The observations suggest that precipitating magnetosheathlike electrons at nominal dayside cleft latitudes are at times modulated with frequencies similar to those of upstream waves. These particles may play an important role, via modification of ionospheric currents and conductivities, in the transmission of upstream wave signals into the magnetosphere and in the generation of dayside high-latitude Pc 3 pulsations.

Cryogenic Field Measurement of Pr2Fe14B Undulator and Performance Enhancement Options at the NSLS-II

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

Tanabe, T.; Chubar, O.; Harder, David A.

2009-09-27

Short period (14.5mm) hybrid undulator arrays composed of Praseodymium Iron Boron (Pr{sub 2}Fe{sub 14}B) magnets (CR53, NEOMAX, Inc.) and vanadium permendur poles have been fabricated at Brookhaven National Laboratory. Unlike Neodymium Iron Boron (Nd{sub 2}Fe{sub 14}B) magnets which exhibit spin reorientation at temperatures below 150K, PrFeB arrays monotonically increase performance with lower operating temperature. It opens up the posibility for use in operating a cryo-permanent magnet undulator (CPMU) in the range of 40K to 60K where very efficient cryocoolers are available. Magnetic flux density profiles were measured at various temperature ranges from room temperature down to liquid helium (LHe) usingmore » the Vertical Testing Facility (VTF) at the National Snchrotron Light Source-II (NSLS-II). Temperature variations of phase error have been characterized. In addition, we examined the use of textured Dysprosium (Dy) poles to replace permendur poles to obtain further improvement in performance.« less

Seasonal Variations in Titan's Stratosphere Observed with Cassini/CIRS: Temperature, Trace Molecular Gas and Aerosol Mixing Ratio Profiles

NASA Technical Reports Server (NTRS)

Vinatier, S.; Bezard, B.; Anderson, C. M.; Coustenis, A.; Teanby, N.

2012-01-01

Titan's northern spring equinox occurred in August 2009. General Circulation Models (e.g. Lebonnois et al., 2012) predict strong modifications of the global circulation in this period, with formation of two circulation cells instead of the pole-to-pole cell that occurred during northern winter. This winter single cell, which had its descending branch at the north pole, was at the origin of the enrichment of molecular abundances and high stratopause temperatures observed by Cassini/CIRS at high northern latitudes (e.g. Achterberg et al., 2011, Coustenis et al., 2010, Teanby et al., 2008, Vinatier et al., 2010). The predicted dynamical seasonal variations after the equinox have strong impact on the spatial distributions of trace gas, temperature and aerosol abundances. We will present here an analysis of CIRS limb-geometry datasets acquired in 2010 and 2011 that we used to monitor the seasonal evolution of the vertical profiles of temperature, molecular (C2H2, C2H6, HCN, ..) and aerosol abundances.

7 CFR 1724.51 - Design requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., galloping or conductor separation, design loads, structure strength limitations, insulator selection and design, guying requirements, and vibration considerations. For lines composed of steel or concrete poles, or steel towers, in which load information will be used to purchase the structures, the design data...

7 CFR 1724.51 - Design requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., galloping or conductor separation, design loads, structure strength limitations, insulator selection and design, guying requirements, and vibration considerations. For lines composed of steel or concrete poles, or steel towers, in which load information will be used to purchase the structures, the design data...

7 CFR 1724.51 - Design requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., galloping or conductor separation, design loads, structure strength limitations, insulator selection and design, guying requirements, and vibration considerations. For lines composed of steel or concrete poles, or steel towers, in which load information will be used to purchase the structures, the design data...

SURFACE TEMPERATURES ON TITAN DURING NORTHERN WINTER AND SPRING

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

Jennings, D. E.; Cottini, V.; Nixon, C. A.

2016-01-01

Meridional brightness temperatures were measured on the surface of Titan during the 2004–2014 portion of the Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five two-year periods show a marked seasonal dependence. The surface temperature near the south pole over this time decreased by 2 K from 91.7 ± 0.3 to 89.7 ± 0.5 K while at the north pole the temperature increased by 1 K from 90.7 ± 0.5 to 91.5 ± 0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the sub-solar latitude. As the latitude changed, the maximum temperature remained constant at 93.65 ± 0.15more » K. In 2010 our temperatures repeated the north–south symmetry seen by Voyager one Titan year earlier in 1980. Early in the mission, temperatures at all latitudes had agreed with GCM predictions, but by 2014 temperatures in the north were lower than modeled by 1 K. The temperature rise in the north may be delayed by cooling of sea surfaces and moist ground brought on by seasonal methane precipitation and evaporation.« less

Brain structural, functional, and cognitive correlates of recent versus remote autobiographical memories in amnestic Mild Cognitive Impairment

PubMed Central

Tomadesso, Clémence; Perrotin, Audrey; Mutlu, Justine; Mézenge, Florence; Landeau, Brigitte; Egret, Stéphanie; de la Sayette, Vincent; Jonin, Pierre-Yves; Eustache, Francis; Desgranges, Béatrice; Chételat, Gaël

2015-01-01

Deficits in autobiographical memory appear earlier for recent than for remote life periods over the course of Alzheimer's disease (AD). The present study aims to further our understanding of this graded effect by investigating the cognitive and neural substrates of recent versus remote autobiographical memories in patients with amnestic Mild Cognitive Impairment (aMCI) thanks to an autobiographical fluency task. 20 aMCI patients and 25 Healthy elderly Controls (HC) underwent neuropsychological tests assessing remote (20-to-30 years old) and recent (the ten last years) autobiographical memory as well as episodic and semantic memory, executive function and global cognition. All patients also had a structural MRI and an FDG-PET scan. Correlations were assessed between each autobiographical memory score and the other tests as well as grey matter volume and metabolism. Within the aMCI, performances for the remote period correlated with personal semantic memory and episodic memory retrieval whereas performances for the recent period only correlated with episodic memory retrieval. Neuroimaging analyses revealed significant correlations between performances for the remote period and temporal pole and temporo-parietal cortex volumes and anterior cingulate gyrus metabolism, while performances for the recent period correlated with hippocampal volume and posterior cingulate, medial prefrontal and hippocampus metabolism. The brain regions related with the retrieval of events from the recent period showed greater atrophy/hypometabolism in aMCI patients compared to HC than those involved in remote memories. Recall of recent memories essentially relies on episodic memory processes and brain network while remote memories also involve other processes such as semantic memory. This is consistent with the semanticization of memories with time and may explain the better resistance of remote memory in AD. PMID:26106572

Brain structural, functional, and cognitive correlates of recent versus remote autobiographical memories in amnestic Mild Cognitive Impairment.

PubMed

Tomadesso, Clémence; Perrotin, Audrey; Mutlu, Justine; Mézenge, Florence; Landeau, Brigitte; Egret, Stéphanie; de la Sayette, Vincent; Jonin, Pierre-Yves; Eustache, Francis; Desgranges, Béatrice; Chételat, Gaël

2015-01-01

Deficits in autobiographical memory appear earlier for recent than for remote life periods over the course of Alzheimer's disease (AD). The present study aims to further our understanding of this graded effect by investigating the cognitive and neural substrates of recent versus remote autobiographical memories in patients with amnestic Mild Cognitive Impairment (aMCI) thanks to an autobiographical fluency task. 20 aMCI patients and 25 Healthy elderly Controls (HC) underwent neuropsychological tests assessing remote (20-to-30 years old) and recent (the ten last years) autobiographical memory as well as episodic and semantic memory, executive function and global cognition. All patients also had a structural MRI and an FDG-PET scan. Correlations were assessed between each autobiographical memory score and the other tests as well as grey matter volume and metabolism. Within the aMCI, performances for the remote period correlated with personal semantic memory and episodic memory retrieval whereas performances for the recent period only correlated with episodic memory retrieval. Neuroimaging analyses revealed significant correlations between performances for the remote period and temporal pole and temporo-parietal cortex volumes and anterior cingulate gyrus metabolism, while performances for the recent period correlated with hippocampal volume and posterior cingulate, medial prefrontal and hippocampus metabolism. The brain regions related with the retrieval of events from the recent period showed greater atrophy/hypometabolism in aMCI patients compared to HC than those involved in remote memories. Recall of recent memories essentially relies on episodic memory processes and brain network while remote memories also involve other processes such as semantic memory. This is consistent with the semanticization of memories with time and may explain the better resistance of remote memory in AD.

Photometric Properties of Enceladus' South Polar Terrain

NASA Astrophysics Data System (ADS)

Annex, Andrew; Verbiscer, A. J.; Helfenstein, P.

2012-10-01

Cassini images reveal in exquisite detail the complex and varied terrains within the geologically active south pole of Enceladus. The region is dominated by four parallel rifts or sulci, informally known as tiger stripes, from which plumes comprised primarily of water vapor erupt [1,2]. The rich data set of Cassini images acquired at high spatial resolution (< 0.5 km/pixel) and a variety of viewing and illumination geometries enables the quantitative analysis of surface scattering properties through disk-resolved photometry. Here we investigate the photometric properties of individual terrain units [3] through fits of the Hapke photometric model [4] to data acquired in the clear (CL1 CL2), UV3, GRN, and IR3 filters, centered at 0.61, 0.34, 0.57, and 0.93 μm, respectively. Terrain units include the tiger stripe smooth and platy plank formations, tiger stripe medial dorsum structures, relict tiger stripe structures, south pole funiscular (ropy) plains, south pole lateral fold-and-wedge formations, and the south pole reticulated plains. Despite the constant, ubiquitous infall of plume particles onto the surface, differences in scattering properties, texture, and albedo among terrain units can be discerned. Work supported by NASA's Cassini Data Analysis Program. [1] Porco et al. 2006 Science 311, 1393-1401. [2] Hansen et al. 2008 Nature 456, 477-479. [3] Spencer et al. 2009 in Saturn from Cassini-Huygens (M. K. Dougherty et al. Eds.) 683-724. [4] Hapke 2002 Icarus 157, 523-534.

Design Considerations of a Transverse Flux Machine for Direct-Drive Wind Turbine Applications: Preprint

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

Husain, Tausif; Hasan, Iftekhar; Sozer, Yilmaz

This paper presents the design considerations of a double-sided transverse flux machine (TFM) for direct-drive wind turbine applications. The TFM has a modular structure with quasi-U stator cores and ring windings. The rotor is constructed with ferrite magnets in a flux-concentrating arrangement to achieve high air gap flux density. The design considerations for this TFM with respect to initial sizing, pole number selection, key design ratios, and pole shaping are presented in this paper. Pole number selection is critical in the design process of a TFM because it affects both the torque density and power factor under fixed magnetic andmore » changing electrical loading. Several key design ratios are introduced to facilitate the design procedure. The effect of pole shaping on back-emf and inductance is also analyzed. These investigations provide guidance toward the required design of a TFM for direct-drive applications. The analyses are carried out using analytical and three-dimensional finite element analysis. A prototype is under construction for experimental verification.« less

On the Double Pole Structure of the Λ(1405)

NASA Astrophysics Data System (ADS)

Roca, Luis; Nieves, Juan; Oset, Eulogio

In the last decade there have been increased theoretical and experimental evidences about the existence of two poles associated to the Λ(1405). In this contribution we summarize several recent works presenting a successful strategy to extract the position of the two Λ(1405) poles from experimental photoproduction data on the γp → KπΣ reaction at Jefferson Lab. The idea is based on considering a production mechanism as model independent as possible and implementing the final state interaction of the final meson-baryon pair based on small modifications of the unitary chiral perturbation theory amplitudes. Precise values for the two poles of the Λ(1405) resonance are then provided. On the other hand, we also present other work where we analyze theoretically the Λb → J/ψK-p reaction from where a recent LHCb experiment extracts a Λ(1405) contribution in the K-p spectrum close to threshold and two baryon states of hidden charm in the J/ψ p spectrum, claimed to be pentaquarks. By assuming that the observed narrow state around 4450 MeV has a nature stemming mostly from {\\bar{D}}\

Conformal amplitude hierarchy and the Poincaré disk

NASA Astrophysics Data System (ADS)

Shimada, Hirohiko

2018-02-01

The amplitude for the singlet channels in the 4-point function of the fundamental field in the conformal field theory of the 2d O(n) model is studied as a function of n. For a generic value of n, the 4-point function has infinitely many amplitudes, whose landscape can be very spiky as the higher amplitude changes its sign many times at the simple poles, which generalize the unique pole of the energy operator amplitude at n = 0. In the stadard parameterization of n by angle in unit of π, we find that the zeros and poles happen at the rational angles, forming a hierarchical tree structure inherent in the Poincaré disk. Some relation between the amplitude and the Farey path, a piecewise geodesic that visits these zeros and poles, is suggested. In this hierarchy, the symmetry of the congruence subgroup Γ(2) of SL(2, ℤ) naturally arises from the two clearly distinct even/odd classes of the rational angles, in which one respectively gets the truncated operator algebras and the logarithmic 4-point functions.

Design Considerations of a Transverse Flux Machine for Direct-Drive Wind Turbine Applications

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

Husain, Tausif; Hasan, Iftekhar; Sozer, Yilmaz

This paper presents the design considerations of a double-sided transverse flux machine (TFM) for direct-drive wind turbine applications. The TFM has a modular structure with quasi-U stator cores and ring windings. The rotor is constructed with ferrite magnets in a flux-concentrating arrangement to achieve high air gap flux density. The design considerations for this TFM with respect to initial sizing, pole number selection, key design ratios, and pole shaping are presented in this paper. Pole number selection is critical in the design process of a TFM because it affects both the torque density and power factor under fixed magnetic andmore » changing electrical loading. Several key design ratios are introduced to facilitate the design procedure. The effect of pole shaping on back-emf and inductance is also analyzed. These investigations provide guidance toward the required design of a TFM for direct-drive applications. The analyses are carried out using analytical and three-dimensional finite element analysis. A prototype is under construction for experimental verification.« less

Location selection and layout for LB10, a lunar base at the Lunar North Pole with a liquid mirror observatory

NASA Astrophysics Data System (ADS)

Detsis, Emmanouil; Doule, Ondrej; Ebrahimi, Aliakbar

2013-04-01

We present the site selection process and urban planning of a Lunar Base for a crew of 10 (LB10), with an infrared astronomical telescope, based on the concept of the Lunar LIquid Mirror Telescope. LB10 is a base designated for permanent human presence on the Moon. The base architecture is based on utilization of inflatable, rigid and regolith structures for different purposes. The location for the settlement is identified through a detailed analysis of surface conditions and terrain parameters around the Lunar North and South Poles. A number of selection criteria were defined regarding construction, astronomical observations, landing and illumination conditions. The location suggested for the settlement is in the vicinity of the North Pole, utilizing the geographical morphology of the area. The base habitat is on a highly illuminated and relatively flat plateau. The observatory in the vicinity of the base, approximately 3.5 kilometers from the Lunar North Pole, inside a crater to shield it from Sunlight. An illustration of the final form of the habitat is also depicted, inspired by the baroque architectural form.

Research on Electromagnetic Force Distribution and Vibration Performance of A Novel 10/4 Switched Reluctance Motor

NASA Astrophysics Data System (ADS)

Fu, Ziyu; Wang, Xinyu; Cao, Cheng; Liu, Meng; Wang, Kangxi

2017-06-01

Radial electromagnetic force is one of the main reasons causing the vibration and noise of the switched reluctance motor. Based on this, the novel structure of 10/4 pole switched reluctance motor is proposed, which increases the air gap flux and electromagnetic torque by increasing the number of stator poles. In addition, the excitation current of the stator winding is reduced by early turn-off angle. Through the finite element modelling analysis, the results show the superiority of the new type of switched reluctance motor. In the end, the vibration characteristics of the conventional motor and the new motor are compared and analysed, and the effect of the structure of this new type of switched reluctance motor is verified.

Paleomagnetic contributions to the Klamath Mountains terrane puzzle-a new piece from the Ironside Mountain batholith, northern California

USGS Publications Warehouse

Mankinen, Edward A.; Gromme, C. Sherman; Irwin, W. Porter

2013-01-01

We obtained paleomagnetic samples from six sites within the Middle Jurassic Ironside Mountain batholith (~170 Ma), which constitutes the structurally lowest part of the Western Hayfork terrane, in the Klamath Mountains province of northern California and southern Oregon. Structural attitudes measured in the coeval Hayfork Bally Meta-andesite were used to correct paleomagnetic data from the batholith. Comparing the corrected paleomagnetic pole with a 170-Ma reference pole for North America indicates 73.5° ± 10.6° of clockwise rotation relative to the craton. Nearly one-half of this rotation may have occurred before the terrane accreted to the composite Klamath province at ~168 Ma. No latitudinal displacement of the batholith was detected.

Fifteen-year growth patterns after thinning a ponderosa-Jeffrey pine plantation in northeastern California

Treesearch

William W. Oliver

1979-01-01

Growth was analyzed after one thinning in a plantation of pole-size ponderosa and Jeffrey pines on land having a site index of 50 feet at 50 years. Periodic annual increment was determined for each of three 5-year periods. On this basis, increment in diameter and cubic volume were found to he related closely to stand basal area only. Basal area and height increment,...

Force interaction and 3D pole movement in double poling.

PubMed

Stöggl, T; Holmberg, H-C

2011-12-01

The aim of this study was to analyze double poling using combined kinetic and 3D kinematic analysis at high skiing speeds as regards pole force components, pole angles and pole behavior during the poling and swing phase. The hypothesis was that a horizontal pole force is more predictive for maximal skiing speed (V(max)) than the resultant pole force. Sixteen elite skiers performed a double-poling V(max) test while treadmill roller skiing. Pole forces and 3D kinematics of pole movement at a speed of 30 km/h were analyzed and related to V(max). The duration of the "preparation phase" showed the strongest relationship with V(max) (r=0.87, P<0.001). Faster skiers generated longer cycle lengths with longer swing and poling times, had less inclined pole angles at pole plant and a later peak pole force. Horizontal pole forces were not more highly related to V(max) compared with the resultant pole force. Impact force was not related to V(max). At high skiing speeds, skiers should aim to combine high pole forces with appropriate timing of pole forces and appropriate pole and body positions during the swing and poling phase. The emphasis in training should be on the development of specific strength capacities for pole force production and the utilization of these capacities in double-poling training sessions. © 2011 John Wiley & Sons A/S.

Fault-tolerant control of large space structures using the stable factorization approach

NASA Technical Reports Server (NTRS)

Razavi, H. C.; Mehra, R. K.; Vidyasagar, M.

1986-01-01

Large space structures are characterized by the following features: they are in general infinite-dimensional systems, and have large numbers of undamped or lightly damped poles. Any attempt to apply linear control theory to large space structures must therefore take into account these features. Phase I consisted of an attempt to apply the recently developed Stable Factorization (SF) design philosophy to problems of large space structures, with particular attention to the aspects of robustness and fault tolerance. The final report on the Phase I effort consists of four sections, each devoted to one task. The first three sections report theoretical results, while the last consists of a design example. Significant results were obtained in all four tasks of the project. More specifically, an innovative approach to order reduction was obtained, stabilizing controller structures for plants with an infinite number of unstable poles were determined under some conditions, conditions for simultaneous stabilizability of an infinite number of plants were explored, and a fault tolerance controller design that stabilizes a flexible structure model was obtained which is robust against one failure condition.

The orbits of satellites of (22) Kalliope and (317) Roxane

NASA Astrophysics Data System (ADS)

Drummond, Jack D.; Reynolds, Odell; Buckman, Miles; Eickhoff, Mark

2017-10-01

Between October 2016 and February 2017 we imaged asteroid (22) Kalliope (10.3

Intrarenal Surgery vs Percutaneous Nephrolithotomy in the Management of Lower Pole Stones Greater than 2 cm.

PubMed

Koyuncu, Hakan; Yencilek, Faruk; Kalkan, Mehmet; Bastug, Yavuz; Yencilek, Esin; Ozdemir, Ahmet Tunc

2015-01-01

To compare the efficacy of RIRS and PNL in lower pole stones ≥ 2 cm. Materials and and Methods: A total of 109 patients who underwent PNL or RIRS for solitary lower pole stone between April 2009 and December 2012, were retrospectively analyzed. Lower pole stone was diagnosed with CT scan. Stone size was assessed as the longest axis of the stone. All patients were informed about the advantages, disadvantages and probable complications of both PNL and RIRS before the selection of the procedure. Patients decided the surgery type by themselves without being under any influences and written informed consent was obtained from all patients prior to the surgery. Patients were divided into two groups according to the patients' preference of surgery type. Group 1 consisted of 77 patients who underwent PNL and Group 2 consisted of 32 patients treated with RIRS. Stone free statuses, postoperative complications, operative time and hospitalization time were compared in both groups. There was no statistical significance between the two groups in mean age, stone size, stone laterality, mean follow-up periods and mean operative times. In PNL group, stone-free rate was 96.1% at first session and 100% after the additional procedure. In Group 2, stone-free rate was 90.6% at the first procedure and 100% after the additional procedure. The final stone-free rates and operative times were similar in both groups. RIRS should be an effective treatment alternative to PNL in lower pole stones larger than 2 cm, especially in selected patients.

Intrarenal Surgery vs Percutaneous Nephrolithotomy in the Management of Lower Pole Stones Greater than 2 cm

PubMed Central

Koyuncu, Hakan; Yencilek, Faruk; Kalkan, Mehmet; Bastug, Yavuz; Yencilek, Esin; Ozdemir, Ahmet Tunc

2015-01-01

Purpose To compare the efficacy of RIRS and PNL in lower pole stones ≥2 cm. Materials and and Methods: A total of 109 patients who underwent PNL or RIRS for solitary lower pole stone between April 2009 and December 2012, were retrospectively analyzed. Lower pole stone was diagnosed with CT scan. Stone size was assessed as the longest axis of the stone. All patients were informed about the advantages, disadvantages and probable complications of both PNL and RIRS before the selection of the procedure. Patients decided the surgery type by themselves without being under any influences and written informed consent was obtained from all patients prior to the surgery. Patients were divided into two groups according to the patients’ preference of surgery type. Group 1 consisted of 77 patients who underwent PNL and Group 2 consisted of 32 patients treated with RIRS. Stone free statuses, postoperative complications, operative time and hospitalization time were compared in both groups. Results There was no statistical significance between the two groups in mean age, stone size, stone laterality, mean follow-up periods and mean operative times. In PNL group, stone-free rate was 96.1% at first session and 100% after the additional procedure. In Group 2, stone-free rate was 90.6% at the first procedure and 100% after the additional procedure. The final stone-free rates and operative times were similar in both groups. Conclusions RIRS should be an effective treatment alternative to PNL in lower pole stones larger than 2 cm, especially in selected patients. PMID:26005965

Automatic Detection and Classification of Pole-Like Objects for Urban Cartography Using Mobile Laser Scanning Data

PubMed Central

Ordóñez, Celestino; Cabo, Carlos; Sanz-Ablanedo, Enoc

2017-01-01

Mobile laser scanning (MLS) is a modern and powerful technology capable of obtaining massive point clouds of objects in a short period of time. Although this technology is nowadays being widely applied in urban cartography and 3D city modelling, it has some drawbacks that need to be avoided in order to strengthen it. One of the most important shortcomings of MLS data is concerned with the fact that it provides an unstructured dataset whose processing is very time-consuming. Consequently, there is a growing interest in developing algorithms for the automatic extraction of useful information from MLS point clouds. This work is focused on establishing a methodology and developing an algorithm to detect pole-like objects and classify them into several categories using MLS datasets. The developed procedure starts with the discretization of the point cloud by means of a voxelization, in order to simplify and reduce the processing time in the segmentation process. In turn, a heuristic segmentation algorithm was developed to detect pole-like objects in the MLS point cloud. Finally, two supervised classification algorithms, linear discriminant analysis and support vector machines, were used to distinguish between the different types of poles in the point cloud. The predictors are the principal component eigenvalues obtained from the Cartesian coordinates of the laser points, the range of the Z coordinate, and some shape-related indexes. The performance of the method was tested in an urban area with 123 poles of different categories. Very encouraging results were obtained, since the accuracy rate was over 90%. PMID:28640189

Jupiter Down Under

NASA Image and Video Library

2016-09-02

This image from NASA's Juno spacecraft provides a never-before-seen perspective on Jupiter's south pole. The JunoCam instrument acquired the view on August 27, 2016, when the spacecraft was about 58,700 miles (94,500 kilometers) above the polar region. At this point, the spacecraft was about an hour past its closest approach, and fine detail in the south polar region is clearly resolved. Unlike the equatorial region's familiar structure of belts and zones, the poles are mottled by clockwise and counterclockwise rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. The south pole has never been seen from this viewpoint, although the Cassini spacecraft was able to observe most of the polar region at highly oblique angles as it flew past Jupiter on its way to Saturn in 2000. http://photojournal.jpl.nasa.gov/catalog/PIA21032

Moon - North Pole Mosaic

NASA Technical Reports Server (NTRS)

1992-01-01

This view of the Moon's north pole is a mosaic assembled from 18 images taken by Galileo's imaging system through a green filter as the spacecraft flew by on December 7, 1992. The left part of the Moon is visible from Earth; this region includes the dark, lava-filled Mare Imbrium (upper left); Mare Serenitatis (middle left); Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is seen at the center of the image. The Moon's north pole is located just inside the shadow zone, about a third of the way from the top left of the illuminated region.

Upper pole access is safe and effective for pediatric percutaneous nephrolithotomy.

PubMed

Oner, Sedat; Karagozlu Akgul, Ahsen; Demirbas, Murat; Onen, Efe; Aydos, Murat; Erdogan, Abdullah

2018-04-01

Upper pole access in percutaneous nephrolithotomy (PCNL) provides a straight tract to the ureter, resulting in easier placement of a guidewire to the ureter, good exposure of the pelvis, calices, and upper ureter, and comfortable manipulations. However, despite these benefits, upper pole access is usually avoided because of the risk of chest complications in both pediatric and adult patients. We aimed to evaluate the safety and morbidity of single upper pole access in pediatric patients undergoing PCNL. We retrospectively reviewed patients aged ≤17 years with renal stones who underwent PCNL with a single access between August 2004 and February 2016. The patients were separated into two groups: the single upper pole access group (SUPAG) and the single other pole access group (SOPAG). We compared the SUPAG and SOPAG in terms of the demographic features of the patients, stone burden and location, operative data, and postoperative outcomes. Complications were classified according to the modified Clavien system. During the study period, 101 PCNL procedures were performed, 77 of which were managed with only one access. The median age of the 77 patients managed with a single access was 12 years (range 3-17 years). The number of cases in the SUPAG and SOPAG was 10 and 67, respectively. There were no statistically significant differences between the SUPAG and SOPAG in terms of age, sex, stone location, hydronephrosis status, stone area, side of kidney, and previous stone treatment or renal surgery. Furthermoret, there were no significant differences between the groups in terms of the operative parameters. Although the difference was insignificant, the median operation times in the SUPAG and SOPAG were 37 and 45 min, respectively. There was no chest complication or bleeding that required transfusion in the SUPAG. Two cases required transfusion, and one case was managed with a double pigtail catheter (double-J) placement because of prolonged extravasation in the SOPAG. The stone-free ratios were 100% and 82.1% in the SUPAG and SOPAG, respectively. Upper pole access provides similar outcomes to other (middle and lower) pole accesses, and may be performed without serious complications. These results indicate that this is a safe and effective approach of PCNL, and it presents a good alternative for removal of renal stones in pediatric patients. Copyright © 2018 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

High speed, precision motion strategies for lightweight structures

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1987-01-01

Abstracts of published papers and dissertations generated during the reporting period are compiled. Work on fine motion control was completed. Specifically, real time control of flexible manipulator vibrations were experimentally investigated. A linear model based on the application of Lagrangian dynamics to a rigid body mode and a series of separable flexible modes was examined with respect to model order requirements, and modal candidate selection. State feedback control laws were implemented based upon linear quadratic regulator design. Specification of the closed loop poles in the regulator design process was obtained by inclusion of a prescribed degree of stability in the manipulator model. Work on gross motion planning and control is also summarized. A systematic method to symbolically derive the full nonlinear dynamic equations of motion of multi-link flexible manipulators was developed.

A two-dimensional model of odd nitrogen in the thermosphere and mesosphere

NASA Technical Reports Server (NTRS)

Gerard, J. C.; Roble, R. G.; Rusch, D. W.

1980-01-01

Satellite measurements of the global nitric oxide distribution demonstrating the need for a two dimensional model of odd nitrogen photochemistry and transport in the thermosphere and mesosphere are reviewed. The main characteristics of a new code solving the transport equation for N(4S), N(2D), and N0 are given. This model extends from pole to pole between 75 and 275 km and reacts to the magnetic activity, the ultraviolet solar flux, and the neutral wind field. The effects of ionization and subsequent odd nitrogen production by high latitude particle precipitation are also included. Preliminary results are illustrated for a magnetically quiet solar minimum period with no neutral wind.

International Heliophysical Year

NASA Technical Reports Server (NTRS)

Davila, J. M.; Harrison, R.; Poland, A.; St.Cyr, O. C.; Thompson, B. J.; Rabin, Douglas (Technical Monitor)

2002-01-01

In 1957 a program of international research, inspired by the International Polar Years of 1882-83 and 1932-33, was organized as the International Geophysical Year (IGY) to study global phenomena of the Earth and geospace. The IGY involved about 60,000 scientists from 66 nations, working at thousands of stations, from pole to pole to obtain simultaneous, global observations on Earth and in space. There had never been anything like it before. The fiftieth anniversary of the International Geophysical Year will occur in 2007. We propose to organize an international program of scientific collaboration for this time period called the International Heliophysical Year (IHY). Like it predecessors, the IHY will focus on fundamental global questions of Earth science.

An experimental analysis of strontium titanate ceramic substrates polished by magnetorheological finishing with dynamic magnetic fields formed by rotating magnetic poles

NASA Astrophysics Data System (ADS)

Pan, Jisheng; Yu, Peng; Yan, Qiusheng; Li, Weihua

2017-05-01

Strontium titanate (SrTiO3, STO) ceramic substrate is an incipient ferroelectric material with a perovskite structure and which has a wide range of applications in the fields of microwave, millimetre wave, and optic fibre. This paper reports on a system of experiments carried out on STO substrates using a new magnetorheological (MR) finishing process where dynamic magnetic fields are formed by magnetic poles rotate. The results show that a circular ring shaped polishing belt with a stability evaluation zone appears on the surface after being polished by MR finishing with a single-point dynamic magnetic field. The dynamic magnetic fields are stronger when the revolutions of magnetic pole increase and eccentricity of pole enlarge, with the surface finish is smoother and more material is removed. The optimum machining times, machining gap, oscillation distance, eccentricity of pole, revolutions of the workpiece and magnetic pole are 60 min, 0.8 mm, 0 mm, 7 mm, and 350 r min-1 and 90 r min-1, respectively, and the best MR fluid consists of 6 wt% of diamond abrasives in W1 particle size and 18 wt% of carbonyl iron powder in W3.5 particle size. A surface roughness of Ra and a material removal rate of 8 nm and 0.154 μm min-1 can be obtained in these optimum process conditions. Finally, the polishing mechanism for dynamic magnetic fields and the mechanism for removing material from STO ceramic substrates are discussed in detail.

Dynamic Echo Information Guides Flight in the Big Brown Bat

PubMed Central

Warnecke, Michaela; Lee, Wu-Jung; Krishnan, Anand; Moss, Cynthia F.

2016-01-01

Animals rely on sensory feedback from their environment to guide locomotion. For instance, visually guided animals use patterns of optic flow to control their velocity and to estimate their distance to objects (e.g., Srinivasan et al., 1991, 1996). In this study, we investigated how acoustic information guides locomotion of animals that use hearing as a primary sensory modality to orient and navigate in the dark, where visual information is unavailable. We studied flight and echolocation behaviors of big brown bats as they flew under infrared illumination through a corridor with walls constructed from a series of individual vertical wooden poles. The spacing between poles on opposite walls of the corridor was experimentally manipulated to create dense/sparse and balanced/imbalanced spatial structure. The bats’ flight trajectories and echolocation signals were recorded with high-speed infrared motion-capture cameras and ultrasound microphones, respectively. As bats flew through the corridor, successive biosonar emissions returned cascades of echoes from the walls of the corridor. The bats flew through the center of the corridor when the pole spacing on opposite walls was balanced and closer to the side with wider pole spacing when opposite walls had an imbalanced density. Moreover, bats produced shorter duration echolocation calls when they flew through corridors with smaller spacing between poles, suggesting that clutter density influences features of the bat’s sonar signals. Flight speed and echolocation call rate did not, however, vary with dense and sparse spacing between the poles forming the corridor walls. Overall, these data demonstrate that bats adapt their flight and echolocation behavior dynamically when flying through acoustically complex environments. PMID:27199690

Terahertz generation by difference frequency generation from a compact optical parametric oscillator

NASA Astrophysics Data System (ADS)

Li, Zhongyang; Wang, Silei; Wang, Mengtao; Wang, Weishu

2017-11-01

Terahertz (THz) generation by difference frequency generation (DFG) processes with dual idler waves is theoretically analyzed. The dual idler waves are generated by a compact optical parametric oscillator (OPO) with periodically poled lithium niobate (PPLN). The phase-matching conditions in a same PPLN for the optical parametric oscillation generating signal and idler waves and for the DFG generating THz waves can be simultaneously satisfied by selecting the poling period of PPLN. Moreover, 3-order cascaded DFG processes generating THz waves can be realized in the same PPLN. To take an example of 8.341 THz which locates in the vicinity of polariton resonances, THz intensities and quantum conversion efficiencies are calculated. Compared with non-cascaded DFG processes, THz intensities of 8.341 THz in 3-order cascaded DFG processes increase to 2.57 times. When the pump intensity equals to 20 MW/mm2, the quantum conversion efficiency of 106% in 3-order cascaded DFG processes can be realized, which exceeds the Manley-Rowe limit.

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes

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

Nong, Hanond, E-mail: Nong.Hanond@rub.de; Markmann, Sergej; Hekmat, Negar

2014-09-15

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunesmore » the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.« less

Performance and microbial community structure of a polar Arctic Circle aerobic granular sludge system operating at low temperature.

PubMed

Gonzalez-Martinez, Alejandro; Muñoz-Palazon, Barbara; Maza-Márquez, Paula; Rodriguez-Sanchez, Alejandro; Gonzalez-Lopez, Jesus; Vahala, Riku

2018-05-01

The aim of this work was to study the performance and microbial community structure of a polar Arctic Circle aerobic granular sludge (AGS) system operating at low temperature. Thus, an AGS bioreactor was operated at 7, 5 and 3 °C of temperature using a cold-adapted sludge from Lapland. At 5 °C, it yielded acceptable conversion rates, in terms of nitrogen, phosphorous, and organic matter. However, under 3 °C a negligible nitrogen and phosphorous removal performance was observed. Below 5 °C, scanning electron microscopy studies showed a wispy, non-dense and irregular granular structure with a strong outgrowth of filamentous. Moreover, Illumina next-generation sequencing showed a heterogeneous microbial population where SM1K20 (Archaea), Trichosporon domesticum (Fungus), and Zooglea, Arcobacter and Acinetobacter (Bacteria) were the dominant phylotypes. Our study suggests that AGS technologies inoculated with North Pole sludge could be operated, in cold regions for a period longer than 3 months (winter season) under 5 °C of water temperature. Copyright © 2018 Elsevier Ltd. All rights reserved.

29 CFR 1917.118 - Fixed ladders.

Code of Federal Regulations, 2011 CFR

2011-07-01

... bolts or structural members of tanks and towers; (3) Ladders built into or vertically attached to..., microwave communications, electrical power and similar towers, poles and structures, including stacks and... consisting of individual rungs that are attached to walls, conical manhole sections or river cells shall: (1...

29 CFR 1917.118 - Fixed ladders.

Code of Federal Regulations, 2010 CFR

2010-07-01

... bolts or structural members of tanks and towers; (3) Ladders built into or vertically attached to..., microwave communications, electrical power and similar towers, poles and structures, including stacks and... consisting of individual rungs that are attached to walls, conical manhole sections or river cells shall: (1...

Low loss pole configuration for multi-pole homopolar magnetic bearings

NASA Technical Reports Server (NTRS)

Blumenstock, Kenneth A. (Inventor); Hakun, Claef F. (Inventor)

2001-01-01

A new pole configuration for multi-pole homopolar bearings proposed in this invention reduces rotational losses caused by eddy-currents generated when non-uniform flux distributions exist along the rotor surfaces. The new homopolar magnetic bearing includes a stator with reduced pole-to-pole and exhibits a much more uniform rotor flux than with large pole-to-pole gaps. A pole feature called a pole-link is incorporated into the low-loss poles to provide a uniform pole-to-pole gap and a controlled path for pole-to-pole flux. In order to implement the low-loss pole configuration of magnetic bearings with small pole-to-pole gaps, a new stator configuration was developed to facilitate installation of coil windings. The stator was divided into sector shaped pieces, as many pieces as there are poles. Each sector-shaped pole-piece can be wound on a standard coil winding machine, and it is practical to wind precision layer wound coils. To achieve maximum actuation efficiency, it is desirable to use all the available space for the coil formed by the natural geometric configuration. Then, the coils can be wound in a tapered shape. After winding, the sectored-pole-pieces are installed into and fastened by bonding or other means, to a ring of material which encloses the sectored-pole-pieces, forming a complete stator.

Approaching Jupiter

NASA Image and Video Library

2017-05-05

This enhanced color view of Jupiter's south pole was created by citizen scientist Gabriel Fiset using data from the JunoCam instrument on NASA's Juno spacecraft. Oval storms dot the cloudscape. Approaching the pole, the organized turbulence of Jupiter's belts and zones transitions into clusters of unorganized filamentary structures, streams of air that resemble giant tangled strings. The image was taken on Dec. 11, 2016 at 9:44 a.m. PST (12:44 p.m. EST), from an altitude of about 32,400 miles (52,200 kilometers) above the planet's beautiful cloud tops. https://photojournal.jpl.nasa.gov/catalog/PIA21390

VizieR Online Data Catalog: Lowell Photometric Database asteroid models (Durech+, 2016)

NASA Astrophysics Data System (ADS)

Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R.

2016-01-01

List of new asteroid models. For each asteroid, there is one or two pole directions in the ecliptic coordinates, the sidereal rotation period, rotation period from LCDB and its quality code (if available), the minimum and maximum lightcurve amplitude, the number of data points, and the method which was used to derive the unique rotation period. The accuracy of the sidereal rotation period is of the order of the last decimal place given. Asteroids marked with asterisk were independently confirmed by Hanus et al. (2016A&A...586A.108H). (2 data files).

Paloma (RX J0524+42): the missing link in magnetic CV evolution?

NASA Astrophysics Data System (ADS)

Schwarz, R.; Schwope, A. D.; Staude, A.; Rau, A.; Hasinger, G.; Urrutia, T.; Motch, C.

2007-10-01

Decent optical photometry of the canditate magnetic CV Paloma has uncovered three persistent periods at 157, 146, and 136 min, which we interpret as the manifestation of the orbital motion of the system, the white dwarf's spin, and a related side-band frequency of the other two. All three periodicities are caused by a double-humped modulation of about 1 mag appearing only at certain fractions of the beat cycle, and it probably originates from one or two accretion spots. Our data is consistent with two plausible solutions, with the spin period being either 146 or 136 min. The appearance of a corresponding spin-folded light curve suggests two different scenarios, for which either pole switching between two diametrically opposed accretion regions (for P_spin = 146 min) or pole migration of one single spot (with P_spin = 136 min) is the preferred accretion mode. Complementary ROSAT X-ray observations and low-resolution spectroscopy provide supporting evidence of the magnetic nature of the object. Depending on the choice of the spin period, the degree of asynchronism with respect to the orbital period is 7% or 14%, implying a beat period of 0.7 or 1.4 days. Thus, the source populates the gap between the near-synchronous polars (<2%) and the DQ Herculis stars with long spin periods (e.g. EX Hya, V1025 Cen, DW Cnc). With an orbital period right within the period gap, Paloma is a key object for magnetic CV evolution: it might be the first bona fide transition object between the DQ Her and AM Her system with a white dwarf currently in the process of synchronisation. Based in part on observations made at Observatoire de Haute Provence (CNRS), France.

Pluto and Triton: Interactions Between Volatiles and Dynamics

NASA Technical Reports Server (NTRS)

Rubincam, D. P.

2001-01-01

Volatiles moving across the surfaces of Pluto and Triton can give rise to interesting dynamical consequences. Conversely, measurement of dynamical states can help constrain the movement of volatiles and interior structure of both bodies. Polar wander may theoretically occur on both Triton and Pluto. Triton's obliquity is low, so that the equatorial regions receive more insolation than the poles. Hence there is a tendency for nitrogen ice to sublime at the equator and condense at the poles, creating polar caps. If the nitrogen supply is large enough, then these caps could move in approximately 10(exp 5) years the global equivalent of 200 m of ice to the poles. At this point the equatorial moment of inertia becomes larger than the moment of inertia measured about the rotation axis, so that Triton overbalances and becomes dynamically unstable. The satellite then undergoes polar wander, restoring stability when the new equator contains the excess matter. Hence the pole may be continually wandering. Neptune raises a permanent tidal bulge on Triton, so that the satellite's surface is elongated like a football, with the long axis pointing at Neptune. This is expected to be the axis about which the pole wanders. Volatile migration would resurface the satellite to some depth and wandering would disturb leading side/trailing side crater statistics. Additional information is contained in the original extended abstract.

A Genome-Wide Analysis of Populations from European Russia Reveals a New Pole of Genetic Diversity in Northern Europe

PubMed Central

Khrunin, Andrey V.; Khokhrin, Denis V.; Filippova, Irina N.; Esko, Tõnu; Nelis, Mari; Bebyakova, Natalia A.; Bolotova, Natalia L.; Klovins, Janis; Nikitina-Zake, Liene; Rehnström, Karola; Ripatti, Samuli; Schreiber, Stefan; Franke, Andre; Macek, Milan; Krulišová, Veronika; Lubinski, Jan; Metspalu, Andres; Limborska, Svetlana A.

2013-01-01

Several studies examined the fine-scale structure of human genetic variation in Europe. However, the European sets analyzed represent mainly northern, western, central, and southern Europe. Here, we report an analysis of approximately 166,000 single nucleotide polymorphisms in populations from eastern (northeastern) Europe: four Russian populations from European Russia, and three populations from the northernmost Finno-Ugric ethnicities (Veps and two contrast groups of Komi people). These were compared with several reference European samples, including Finns, Estonians, Latvians, Poles, Czechs, Germans, and Italians. The results obtained demonstrated genetic heterogeneity of populations living in the region studied. Russians from the central part of European Russia (Tver, Murom, and Kursk) exhibited similarities with populations from central–eastern Europe, and were distant from Russian sample from the northern Russia (Mezen district, Archangelsk region). Komi samples, especially Izhemski Komi, were significantly different from all other populations studied. These can be considered as a second pole of genetic diversity in northern Europe (in addition to the pole, occupied by Finns), as they had a distinct ancestry component. Russians from Mezen and the Finnic-speaking Veps were positioned between the two poles, but differed from each other in the proportions of Komi and Finnic ancestries. In general, our data provides a more complete genetic map of Europe accounting for the diversity in its most eastern (northeastern) populations. PMID:23505534

Ψ-model of micro- and macrosystems

NASA Astrophysics Data System (ADS)

Perepelkin, E. E.; Sadovnikov, B. I.; Inozemtseva, N. G.

2017-08-01

A mathematical model (referred as Ψ-model for convenience) has been developed, which allows describing certain class of micro- and macrosystems. Ψ-model is based on quantum mechanics and classical mechanics of continuous media. Ψ-model describes micro- and macrosystems, in which vector field of velocities of probability flows, charge, mass has specific spiral structure. The field of velocities has spiral structure on concentric spherical surfaces. The velocity field is not defined and has a characteristic property on the poles of sphere and on the axis and tends to zero at infinity. The behavior of Ψ-model can be described in the general case with time-dependent periodic singular solution of the Schrödinger equation. The goal of this paper is to choose a particular probability flux in the continuity equation which we solve in this paper and deduce from it the solution of the Schrödinger equation. For example, in the frame of approach the problem with modified Coulomb potential was considered.

Dynamics and spatial structure of ENSO from re-analyses versus CMIP5 models

NASA Astrophysics Data System (ADS)

Serykh, Ilya; Sonechkin, Dmitry

2016-04-01

Basing on a mathematical idea about the so-called strange nonchaotic attractor (SNA) in the quasi-periodically forced dynamical systems, the currently available re-analyses data are considered. It is found that the El Niño - Southern Oscillation (ENSO) is driven not only by the seasonal heating, but also by three more external periodicities (incommensurate to the annual period) associated with the ~18.6-year lunar-solar nutation of the Earth rotation axis, ~11-year sunspot activity cycle and the ~14-month Chandler wobble in the Earth's pole motion. Because of the incommensurability of their periods all four forces affect the system in inappropriate time moments. As a result, the ENSO time series look to be very complex (strange in mathematical terms) but nonchaotic. The power spectra of ENSO indices reveal numerous peaks located at the periods that are multiples of the above periodicities as well as at their sub- and super-harmonic. In spite of the above ENSO complexity, a mutual order seems to be inherent to the ENSO time series and their spectra. This order reveals itself in the existence of a scaling of the power spectrum peaks and respective rhythms in the ENSO dynamics that look like the power spectrum and dynamics of the SNA. It means there are no limits to forecast ENSO, in principle. In practice, it opens a possibility to forecast ENSO for several years ahead. Global spatial structures of anomalies during El Niño and power spectra of ENSO indices from re-analyses are compared with the respective output quantities in the CMIP5 climate models (the Historical experiment). It is found that the models reproduce global spatial structures of the near surface temperature and sea level pressure anomalies during El Niño very similar to these fields in the re-analyses considered. But the power spectra of the ENSO indices from the CMIP5 models show no peaks at the same periods as the re-analyses power spectra. We suppose that it is possible to improve modeled rhythms if the afore-mentioned external periodicities are taken in an explicit consideration in the models.

New Techniques in Characterization of Ferroelectric Materials

NASA Technical Reports Server (NTRS)

Sehirlioglu, Alp

2008-01-01

Two new techniques have been developed to characterize Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) based ferroelectric single crystals: (i) electro-thermal imaging, and (ii) single crystal x-ray diffraction in the transmission mode. (i) Electro-thermal imaging is a remote sensing technique that can detect the polarization direction and poling state of a whole crystal slice. This imaging technique utilizes an IR camera to determine the field induced temperature change and does not require any special or destructive sample preparation. In the resulting images it is possible to distinguish regions of 180 deg domains. This powerful technique can be used remotely during poling to determine the poling state of the crystal to avoid over-poling that can result in inferior properties and/or cracking of the crystals. Electro-thermal imaging produced the first direct observations of polarization rotation. Under bipolar field, the domains near the corners were the first to switch direction. As the field increased above the coercive field, domains at the center part of the crystals switched direction. (ii) X-ray diffraction in the transmission mode has long been used in structure determination of organic crystals and proteins; however, it is not used much to characterize inorganic systems. 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were examined by this XRD technique for the first time, and a never-before-seen super-lattice was revealed with a doubling of the unit cell in all three directions, giving a cell volume eight times that of a traditional perovskite unit cell. The significance of the super-lattice peaks increased with poling, indicating a structural contribution to ordering. Lack of such observations by electron diffraction in the transmission electron microscope examinations suggests the presence of a bulk effect.

Final Report: Nanoscale Dynamical Heterogeneity in Complex Magnetic Materials

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

Kevan, Stephen

2016-05-27

A magnetic object can be demagnetized by dropping it on a hard surface, but what does ‘demagnetized’ actually mean? In 1919 Heinrich Barkhausen proved the existence of magnetic domains, which are regions of uniform magnetization that are much larger than atoms but much smaller than a macroscopic object. A material is fully magnetized when domain magnetizations are aligned, while it is demagnetized when the domain magnetizations are randomly oriented and the net magnetization is zero. The heterogeneity of a demagnetized object leads to interesting questions. Magnets are unstable when their poles align, and stable when their poles anti-align, so whymore » is the magnetized state ever stable? What do domains look like? What is the structure of a domain wall? How does the magnetized state transform to the demagnetized state? How do domains appear and disappear? What are the statistical properties of domains and how do these vary as the domain pattern evolves? Some of these questions remain the focus of intense study nearly a century after Barkhausen’s discovery. For example, just a few years ago a new kind of magnetic texture called a skyrmion was discovered. A skyrmion is a magnetic domain that is a nanometer-scale, topologically protected vortex. ‘Topologically protected’ means that skyrmions are hard to destroy and so are stable for extended periods. Skyrmions are characterized by integral quantum numbers and are observed to move with little dissipation and so could store and process information with very low power input. Our research project uses soft x-rays, which offer very high magnetic contrast, to probe magnetic heterogeneity and to measure how it evolves in time under external influences. We will condition a soft x-ray beam so that the wave fronts will be coherent, that is, they will be smooth and well-defined. When coherent soft x-ray beam interacts with a magnetic material, the magnetic heterogeneity is imprinted onto the wave fronts and projected into a diffraction pattern. These patterns will be analyzed to understand the structure, motion, and statistical properties of magnetic textures and their boundaries. Over the period covered by this grant we will study a) the structure, phase behaviors, and motion of skyrmions in various thin film materials, and 2) the statistical properties of Barkhausen cascades, which are a key factor in how magnetization varies.« less

Support for the Elimination of Roadside Hazards : Evaluating Roadside Collision Data and Clear Zone Requirements

DOT National Transportation Integrated Search

2009-09-01

Over a three year period (2004-2006), there were more than 60,000 crashes involving fixed objects (trees, utility poles, : culverts, bridge piers, etc.) located within South Carolina roadsides. These fixed object crashes accounted for 20% of all cras...

Can GRACE Explain Some of the Main Interannual Polar Motion Signatures?

NASA Astrophysics Data System (ADS)

Adhikari, S.; Ivins, E. R.; Larour, E. Y.

2016-12-01

GRACE has provided a series of monthly solutions for water mass transport that now span a 14-year period. A natural question to ask is how much of this mass transport information might be used to reconstruct, theoretically, the non-tidal and non-Chandlerian polar motion at interannual time scales. Reconstruction of the pole position at interannual time scales since 2002 has been performed by Chen et al. (2013, GRL) and Adhikari and Ivins (2016, Science Advances). (The main feature of polar motion that has been evolving since the mid 1990's is the increasing dominance of Greenland ice mass loss.) Here we discuss this reconstruction and the level of error that occurs because of missing information about the spherical harmonic degree 1 and 2 terms and the lack of terms associated with angular momentum transfer in the Louiville equations. Using GRACE observations and complementary solutions of self-attraction/loading problem on an elastically compressible rotating earth, we show that ice mass losses from polar ice sheets, and when combined with changes in continental hydrology, explain nearly the entire amplitude (83±23%) and mean directional shift (within 5.9±7.6°) of recently observed eastward polar motion. We also show that decadal scale pole variations are directly linked to global changes in continental hydrology. The energy sources for such motions are likely to be associated with decadal scale ocean and atmospheric oscillations that also drive 20th century continental wet-dry variability. Interannual variability in pole position, therefore, offers a tool for assessing past stability of our climate, and for the future, now faced with an increased intensity in the water cycle and more vulnerable to ice sheet instability. Figure caption: Observed and reconstructed mean annual pole positions with respect to the 2003-2015 mean position. Blue error band is associated with the reconstructed solution; red signifies additional errors that are related to uncertainty in the long-term linear trend. Notice the interannual variability during the GRACE period.

[A quality evaluation tableau for health institutions: an educational tool].

PubMed

Moll, Marie Christine; Decavel, Frédérique; Merlet, Christine

2009-09-01

For a few years, health institutions have had to comply with the certification and the need to establish the new governance. Thanks to the accreditation version 2 (obtained in 2005), the elaboration of the hospital project (adopted in October, 2006) and the organization in poles since 2006, the quality oriented management became a priority axis at the University Hospital of Angers. The strategic adaptation to quality requirements leads to develop the hospital management, more especially at the level of the clinical, medico technical and administrative poles. The elements of the hospital project including the part about the quality, risk and evaluation aim at being adapted by every pole according to the level of its project. This adaptation which is imposed to each pole manager requires a practical and educational accompaniment allowing at the same time to realize a diagnosis of the progress of the quality approach, a measure of the impact of the global impregnation within the institution and a comparison between pole. A eight axis dashboard with criteria and a user guide were developed from certification ISO 9001, the EFQM manual and the certification manual version 2 of the Healthcare High Authorities. The criteria are transcribed in an EXCEL grid ready to use. Succeeding in estimating your own quality system means that you demonstrate the maturity of the quality approach. The results of this evaluation confirmed those of the certification. The dashboard is a management structuring tool at the service of the multidisciplinary team. Two considerations emerge from these results: First of all, for the hospital top management, the axes to be improved emerge as a priority to determine and target the next annual action plans. The results also allow to support the auto evaluation for the certification version 2010 planned in January of the same year. It is a pragmatic tool which allows auto evaluation and comparison to estimate the pole performances. It is a strategic driving tool for the hospital, for the quality department and for the pole. The pole quality system evaluation dashboard for Healthcare institutions is a simple tool which allies strategy and performance for a better efficiency of the actions to be taken to improve the quality, the risk management and the evaluation of the poles for a better service to the hospital users.

Frequency conversion of structured light.

PubMed

Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P

2016-02-15

Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.

Specifications for structural range improvements.

Treesearch

H. Reed Sanderson; Thomas M. Quigley; Emery E. Swan; Louis R. Spink

1990-01-01

Construction specifications and illustrations are provided for several types of barbed wire and pole fences, gates, cattle guards, stiles, spring developments, water troughs, stock ponds, trick tanks, and livestock access trails.

7 CFR 1726.14 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... electric system, e.g., a substation transformer, heat exchanger or a transmission structure. Force account... which is combined with equipment to form an electric system, e.g., poles, insulators, or conductors...

7 CFR 1726.14 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... electric system, e.g., a substation transformer, heat exchanger or a transmission structure. Force account... which is combined with equipment to form an electric system, e.g., poles, insulators, or conductors...

7 CFR 1726.14 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... electric system, e.g., a substation transformer, heat exchanger or a transmission structure. Force account... which is combined with equipment to form an electric system, e.g., poles, insulators, or conductors...

7 CFR 1726.14 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... electric system, e.g., a substation transformer, heat exchanger or a transmission structure. Force account... which is combined with equipment to form an electric system, e.g., poles, insulators, or conductors...

7 CFR 1726.14 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... electric system, e.g., a substation transformer, heat exchanger or a transmission structure. Force account... which is combined with equipment to form an electric system, e.g., poles, insulators, or conductors...

PopZ identifies the new pole, and PodJ identifies the old pole during polar growth in Agrobacterium tumefaciens

PubMed Central

Grangeon, Romain; Zupan, John R.; Anderson-Furgeson, James; Zambryski, Patricia C.

2015-01-01

Agrobacterium tumefaciens elongates by addition of peptidoglycan (PG) only at the pole created by cell division, the growth pole, whereas the opposite pole, the old pole, is inactive for PG synthesis. How Agrobacterium assigns and maintains pole asymmetry is not understood. Here, we investigated whether polar growth is correlated with novel pole-specific localization of proteins implicated in a variety of growth and cell division pathways. The cell cycle of A. tumefaciens was monitored by time-lapse and superresolution microscopy to image the localization of A. tumefaciens homologs of proteins involved in cell division, PG synthesis and pole identity. FtsZ and FtsA accumulate at the growth pole during elongation, and improved imaging reveals FtsZ disappears from the growth pole and accumulates at the midcell before FtsA. The L,D-transpeptidase Atu0845 was detected mainly at the growth pole. A. tumefaciens specific pole-organizing protein (Pop) PopZAt and polar organelle development (Pod) protein PodJAt exhibited dynamic yet distinct behavior. PopZAt was found exclusively at the growing pole and quickly switches to the new growth poles of both siblings immediately after septation. PodJAt is initially at the old pole but then also accumulates at the growth pole as the cell cycle progresses suggesting that PodJAt may mediate the transition of the growth pole to an old pole. Thus, PopZAt is a marker for growth pole identity, whereas PodJAt identifies the old pole. PMID:26324921

Transfer of label from /sup 3/H-glucose in Digitaria eriantha leaves to the rust fungus Puccinia digitariae Pole Evans

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

Rey, M.E.; Garnett, H.M.

1985-08-01

Digitaria eriantha pentzii was fed /sup 3/H-glucose prior to inoculation with uredospores of Puccinia digitariae Pole Evans. Twenty-one hours after inoculation, uptake of label from /sup 3/H-glucose by the primary infection structures of P. digitariae was demonstrated employing autoradiography. These results indicate that an exchange of nutrients between host and pathogen occurs very early on in the infection process, during the formation of the primary infection structures. Despite contrary reports that obligate parasites receive no nutrition before establishment of haustoria, this study supports the work of Andrews, who demonstrated uptake of /sup 3/H-glucose label from lettuce cotyledons into the primarymore » and secondary infection vesicles, appressoria, and germ tubes of Bremia lactucae.« less

Pole structure of the Λ ( 1405 ) in a recent QCD simulation

DOE PAGES

Molina, R.; Doring, M.

2016-09-27

The Λ(1405) baryon is difficult to detect in experiment, absent in many quark model calculations, and supposedly manifested through a two-pole structure. Its uncommon properties made it subject to numerous experimental and theoretical studies in recent years. Lattice-QCD eigenvalues for different quark masses were recently reported by the Adelaide group. We compare these eigenvalues to predictions of a model based on Unitary Chiral Perturbation Theory. The UχPT calculation predicts the quark mass dependence remarkably well. It also explains the overlap pattern with different meson-baryon components, mainly πΣ and K¯N, at different quark masses. As a result, more accurate lattice QCDmore » data are required to draw definite conclusions on the nature of the Λ(1405).« less

Mars Environmental Survey (MESUR): Science objectives and mission description

NASA Technical Reports Server (NTRS)

Hubbard, G. Scott; Wercinski, Paul F.; Sarver, George L.; Hanel, Robert P.; Ramos, Ruben

1992-01-01

In-situ observations and measurements of Mars are objectives of a feasibility study beginning at the Ames Research Center for a mission called the Mars Environmental SURvey (MESUR). The purpose of the MESUR mission is to emplace a pole-to-pole global distribution of landers on the Martian surface to make both short- and long-term observations of the atmosphere and surface. The basic concept is to deploy probes which would directly enter the Mars atmosphere, provide measurements of the upper atmospheric structure, image the local terrain before landing, and survive landing to perform meteorology, seismology, surface imaging, and soil chemistry measurements. MESUR is intended to be a relatively low-cost mission to advance both Mars science and human presence objectives. Mission philosophy is to: (1) 'grow' a network over a period of years using a series of launch opportunities, thereby minimizing the peak annual costs; (2) develop a level-of-effort which is flexible and responsive to a broad set of objectives; (3) focus on science while providing a solid basis for human exploration; and (4) minimize project cost and complexity wherever possible. In order to meet the diverse scientific objectives, each MESUR lander will carry the following strawman instrument payload consisting of: (1) Atmospheric structure experiment, (2) Descent and surface imagers, (3) Meteorology package, (4) Elemental composition instrument, (5) 3-axis seismometer, and (6) Thermal analyzer/evolved gas analyzer. The feasibility study is primarily to show a practical way to design an early capability for characterizing Mars' surface and atmospheric environment on a global scale. The goals are to answer some of the most urgent questions to advance significantly our scientific knowledge about Mars, and for planning eventual exploration of the planet by robots and humans.

Pole-to-pole biogeography of surface and deep marine bacterial communities

PubMed Central

Ghiglione, Jean-François; Galand, Pierre E.; Pommier, Thomas; Pedrós-Alió, Carlos; Maas, Elizabeth W.; Bakker, Kevin; Bertilson, Stefan; Kirchman, David L.; Lovejoy, Connie; Yager, Patricia L.; Murray, Alison E.

2012-01-01

The Antarctic and Arctic regions offer a unique opportunity to test factors shaping biogeography of marine microbial communities because these regions are geographically far apart, yet share similar selection pressures. Here, we report a comprehensive comparison of bacterioplankton diversity between polar oceans, using standardized methods for pyrosequencing the V6 region of the small subunit ribosomal (SSU) rRNA gene. Bacterial communities from lower latitude oceans were included, providing a global perspective. A clear difference between Southern and Arctic Ocean surface communities was evident, with 78% of operational taxonomic units (OTUs) unique to the Southern Ocean and 70% unique to the Arctic Ocean. Although polar ocean bacterial communities were more similar to each other than to lower latitude pelagic communities, analyses of depths, seasons, and coastal vs. open waters, the Southern and Arctic Ocean bacterioplankton communities consistently clustered separately from each other. Coastal surface Southern and Arctic Ocean communities were more dissimilar from their respective open ocean communities. In contrast, deep ocean communities differed less between poles and lower latitude deep waters and displayed different diversity patterns compared with the surface. In addition, estimated diversity (Chao1) for surface and deep communities did not correlate significantly with latitude or temperature. Our results suggest differences in environmental conditions at the poles and different selection mechanisms controlling surface and deep ocean community structure and diversity. Surface bacterioplankton may be subjected to more short-term, variable conditions, whereas deep communities appear to be structured by longer water-mass residence time and connectivity through ocean circulation. PMID:23045668

Effects of plasmon pole models on the G0W0 electronic structure of various oxides

NASA Astrophysics Data System (ADS)

Miglio, A.; Waroquiers, D.; Antonius, G.; Giantomassi, M.; Stankovski, M.; Côté, M.; Gonze, X.; Rignanese, G.-M.

2012-09-01

The electronic properties of three different oxides (ZnO, SnO2 and SiO2) are investigated within many-body perturbation theory in the G 0 W 0 approximation. The frequency dependence of the dielectric function is either approximated using two different well-established plasmon-pole models (one of which enforces the fulfillment of the f-sum rule) or treated explicitly by means of the contour-deformation approach. Comparing these results, it is found that the plasmon-pole model enforcing the f-sum rule gives less accurate results for all three oxides. The calculated electronic properties are also compared with the available experimental data and previous ab initio results, focusing on the d state binding energies. The G 0 W 0 approach leads to significantly improved band gaps with respect to calculations based on the density functional theory in the local density approximation.

Is cohesin required for spindle-pole-body/centrosome cohesion?

PubMed Central

Jin, Hui; Avey, Martin

2012-01-01

Centrosomes are microtubule-organizing centers that nucleate spindle microtubules during cell division. In budding yeast, the centrosome, often referred to as the spindle pole body, shares structural components with the centriole, the central core of the animal centrosome. The parental centrosome is duplicated when DNA replication takes place. Like sister chromatids tethered together by cohesin, duplicated centrosomes are linked and then separate to form the bipolar spindle necessary for chromosome segregation. Recent studies have shown that cohesin is also localized to the animal centrosome and is perhaps directly involved in engaging paired centrioles. Here we discuss the potential role of cohesin in mediating spindle-pole-body cohesion in the context of yeast meiosis. We propose that the coordination of chromosome segregation with centrosome cohesion and duplication is mediated by the antagonistic interaction between the Aurora kinase and the Polo kinase and that the role of cohesin in centrosome regulation appears to be indirect in budding yeast. PMID:22482005

Forest ecology and management

Treesearch

William D. Boyer; James H. Miller

1994-01-01

Over a period of 16 years, unburned longleaf pine (Pinus palustris Mill.) pole stands grew an average of 27% more volume than similar stands regularly burned. Treatments included biennial burns in winter, spring, and summer plus an unburned check, each of which was combined with three supplemental treatments, namely, initial herbicide injection of...

Pulkovo IVS Analysis Center (PUL) 2012 Annual Report

NASA Technical Reports Server (NTRS)

Malkin, Zinovy; Sokolova, Julia

2013-01-01

This report briefly presents the PUL IVS Analysis Center activities during 2012 and plans for the coming year. The main topics of the investigations of PUL staff in that period were ICRF related studies, computation and analysis of EOP series, celestial pole offset (CPO) modeling, and VLBI2010 related issues.

On the Long-Term "Hesitation Waltz" Between the Earth's Figure and Rotation Axes

NASA Astrophysics Data System (ADS)

Couhert, A.; Mercier, F.; Bizouard, C.

2017-12-01

The principal figure axis of the Earth refers to its axis of maximum inertia. In the absence of external torques, the latter should closely coincide with the rotation pole, when averaged over many years. However, because of tidal and non-tidal mass redistributions within the Earth system, the rotational axis executes a circular motion around the figure axis essentially at seasonal time scales. In between, it is not clear what happens at decadal time spans and how well the two axes are aligned. The long record of accurate Satellite Laser Ranging (SLR) observations to Lageos makes possible to directly measure the long time displacement of the figure axis with respect to the crust, through the determination of the degree 2 order 1 geopotential coefficients for the 34-year period 1983-2017. On the other hand, the pole coordinate time series (mainly from GNSS and VLBI data) yield the motion of the rotation pole with even a greater accuracy. This study is focused on the analysis of the long-term behavior of the two time series, as well as the derivation of possible explanations for their discrepancies.

Cryogenic Field Measurement of Pr{sub 2}Fe{sub 14}B Undulator and Performance Enhancement Options at the NSLS-II

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

Tanabe, Toshiya; Chubar, Oleg; Harder, David A.

2010-06-23

Short period (14.5mm) hybrid undulator arrays composed of Praseodymium Iron Boron (Pr{sub 2}Fe{sub 14}B) magnets (CR53, NEOMAX, Inc.) and vanadium permendur poles have been fabricated at Brookhaven National Laboratory. Unlike Neodymium Iron Boron (Nd{sub 2}Fe{sub 14}B) magnets which exhibit spin reorientation at a temperatures below 150 K, PrFeB arrays monotonically increase performance with lower operating temperature. It opens up the possibility for use in operating a cryo-permanent magnet undulator (CPMU) in the range of 40 K to 60 K where very efficient cryocoolers are available. Magnetic flux density profiles were measured at various temperature ranges from room temperature down tomore » liquid helium (LHe) using the Vertical Testing Facility (VTF) at the National Synchrotron Light Source-II (NSLS-II). Temperature variations of phase error have been characterized. In addition, we examined the use of textured Dysprosium (Dy) poles to replace permendur poles to obtain further improvement in performance.« less

The Spin Vector of (832) Karin

NASA Astrophysics Data System (ADS)

Slivan, Stephen M.; Molnar, L. A.

2010-10-01

We observed rotation lightcurves of Koronis family and Karin cluster member (832) Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of 18.352 h, spin obliquity near 41°, and pole ecliptic longitude near either 51° or 228°. Although the two ambiguous pole solutions are near the clustered pole solutions of four Koronis family members whose spins are thought to be trapped in a spin-orbit resonance (Vokrouhlický et al., 2003), Karin does not seem to be trapped in the resonance; this is consistent with the expectation that the 6 My age of Karin (Nesvorný et al., 2002) is too young for YORP torques to have modified its spin since its formation. The spin vector and shape results for Karin will constrain family formation models that include spin properties, and we discuss the Karin results in the context of the other members of the Karin cluster, the Karin parent body, and the parent body's siblings in the Koronis family.

VizieR Online Data Catalog: OGLE: Gaia South Ecliptic Pole Field (Soszynski+, 2012)

NASA Astrophysics Data System (ADS)

Soszynski, I.; Udalski, A.; Poleski, R.; Kozlowski, S.; Wyrzykowski, L.; Pietrukowicz, P.; Szymanski, M. K.; Kubiak, M.; Pietrzynski, G.; Ulaczyk, K.; Skowron, J.

2013-03-01

We present a comprehensive analysis of the Gaia South Ecliptic Pole (GSEP) field, 5.3 square degrees area around the South Ecliptic Pole on the outskirts of the LMC, based on the data collected during the fourth phase of the Optical Gravitational Lensing Experiment, OGLE-IV. The GSEP field will be observed during the commissioning phase of the ESA Gaia space mission for testing and calibrating the Gaia instruments. We provide the photometric maps of the GSEP region containing the mean VI photometry of all detected stellar objects and their equatorial coordinates. We show the quality and completeness of the OGLE-IV photometry and color-magnitude diagrams of this region. We conducted an extensive search for variable stars in the GSEP field leading to the discovery of 6789 variable stars. In this sample we found 132 classical Cepheids, 686 RR Lyr type stars, 2819 long-period, and 1377 eclipsing variables. Several objects deserving special attention were also selected, including a new classical Cepheid in a binary eclipsing system. (9 data files).

Structural deformation of 0.74Pb(Mg1/3Nb2/3)O3-0.26PbTiO3 single crystal in 1-3 composites due to interface stresses and poling procedure optimization

NASA Astrophysics Data System (ADS)

Wang, Chunying; Sun, Enwei; Liu, Yingchun; Zhang, Rui; Yang, Bin; Cao, Wenwu

2016-09-01

Interface stresses strongly influence the functional property of 1-3 piezoelectric composites. Using the translucent nature of (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals, we have studied stress distributions and domain configuration changes during poling inside the crystal rods by polarizing light microscopy and piezoresponse force microscopy. It was found that the interface stresses due to interaction with polymeric filler led a deformed rhombohedral phase and caused incomplete poling near rod-edges. Compared with "hard" epoxy (Epotek301) filler, "soft" epoxy (Stycast) filler showed weaker impact on the crystals rods and less influence on domain configurations. We also show that high temperature poling (70 °C) can substantially improve the piezoelectric coefficient of composites filled with hard epoxy due to creeping above the glass transition Tg. Analytic stress distribution equations based on cylinder rods were modified to explain the physical principle and to predict the stress distribution for square rods case, which was verified by finite element simulation to be accurate within 5%.

What Does Titan's Atmosphere Look Like Near The Poles At The End Of The Cassini Mission ?

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Coustenis, A.; Jennings, D. E.; Achterberg, R. K.; Bampasidis, G.; Cottini, V.; Flasar, F. M.; Lavvas, P.

2017-12-01

The Cassini mission ends on Sept. 15, 2017, after - among other - 127 targeted Titan flybys. We have monitored the seasonal evolution near Titan's poles during the mission. Titan's North pole had been enhanced in chemical species since the beginning of the observations, but since 2010, we observe at Titan's south pole a strong temperature decrease and the onset of a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously observed only at high northern latitudes (Coustenis et al. 2016 and references therein). This is due to the transition of Titan's seasons from northern winter in 2002 to northern summer in 2017 and, at the same time, the advent of winter in the south pole, during which time species with longer chemical lifetimes remain in the north for a little longer undergoing slow photochemical destruction, while those with shorter lifetimes disappear, reappearing in the south. An opposite effect has been expected in the North, but not observed with any significant certainty until 2016. We present here an analysis of nadir spectra acquired by Cassini/CIRS (Jennings et al., 2017) at high resolution in the past years and describe the newly observed decrease in chemical abundances of the components in the North. From 2013 until 2016, the Northern polar region has shown a temperature increase of 10 K, while the South had shown a more significant decrease in a similar period of time. The chemical content in the North is finally showing a clear depletion for most molecules since 2015 (Coustenis et al., 2017). References: Coustenis et al., 2016, Icarus 270, 409-420 ; Coustenis et al., 2017, submitted; Jennings et al., 2017, Applied Optics 56, no 18, 5274-5294.

Seasonal and interannual variations of atmospheric CO2 and climate

USGS Publications Warehouse

Dettinger, M.D.; Ghil, M.

1998-01-01

Interannual variations of atmospheric CO2 concentrations at Mauna Loa are almost masked by the seasonal cycle and a strong trend; at the South Pole, the seasonal cycle is small and is almost lost in the trend and interannual variations. Singular-spectrum analysis (SSA) issued here to isolate and reconstruct interannual signals at both sites and to visualize recent decadal changes in the amplitude and phase of the seasonal cycle. Analysis of the Mauna Loa CO2 series illustrates a hastening of the CO2 seasonal cycle, a close temporal relation between Northern Hemisphere (NH) mean temperature trends and the amplitude of the seasonal CO2 cycle, and tentative ties between the latter and seasonality changes in temperature over the NH continents. Variations of the seasonal CO2 cycle at the South Pole differ from those at Mauna Loa: it is phase changes of the seasonal cycle at the South Pole, rather than amplitude changes, that parallel hemispheric and global temperature trends. The seasonal CO2 cycles exhibit earlier occurrences of the seasons by 7 days at Mauna Loa and 18 days at the South Pole. Interannual CO2 variations are shared at the two locations, appear to respond to tropical processes, and can be decomposed mostly into two periodicities, around (3 years)-1 and (4 years)-1, respectively. Joint SSA analyses of CO2 concentrations and tropical climate indices isolate a shared mode with a quasi-triennial (QT) period in which the CO2 and sea-surface temperature (SST) participation are in phase opposition. The other shared mode has a quasi-quadrennial (QQ) period and CO2 variations are in phase with the corresponding tropical SST variations throughout the tropics. Together these interannual modes exhibit a mean lag between tropical SSTs and CO2 variations of about 6-8 months, with SST leading. Analysis of the QT and QQ signals in global gridded SSTs, joint SSA of CO2 and ??13C isotopic ratios, and SSA of CO2 and NH-land temperatures indicate that the QT variations in CO2 mostly reflect upwelling variations in the eastern tropical Pacific. QQ variations are dominated by the CO2 signature of terrestrial-ecosystem response to global QQ climate variations. Climate variations associated with these two interannual components of tropical variability have very different effects on global climate and, especially, on terrestrial ecosystems and the carbon cycle.

The Neoproterozoic-Paleozoic Arctic Margins: early stages of geodynamic evolution and plate reconstructions

NASA Astrophysics Data System (ADS)

Vernikovsky, V. A.; Metelkin, D. V.; Vernikovskaya, A. E.; Matushkin, N. Yu.; Lobkovsky, L. I.; Shipilov, E. V.

2012-04-01

Available data on the existence of Precambrian metamorphic complexes among the main structures of the Arctic led to the suggestion that a large continental mass existed between Laurentia, Baltica and Siberia - an Arctic continent, more often called Arctida (Zonenshain, Natapov, 1987). It is inferred that as an independent continental mass Arctida was formed after the breakup of Rodinia, and in general it can have a pre-Grenvillian (including Grenvillian) basement age. The breakup of this mass and the collision of its fragments with adjacent cratons led to the formation of heterochronous collisional systems. Arctida probably included the Kara, Novosibirsk, Alaska-Chukotka blocks, the blocks of northern Alaska and the submerged Lomonosov Ridge, small fragments of the Inuit fold belt in the north of Greenland and the Canadian archipelago, the structures of the Svalbard and maybe the Timan-Pechora plates. However the inner structure of this paleocontinent, the mutual configuration of the blocks and its evolution in the Neoproterozoic-Paleozoic is still a matter of discussion. The most accurate way of solving these issues is by using paleomagnetic data, but those are nonexistent for most of the defined blocks. Reliable paleomagnetic determinations for the Neoproterozoic-Paleozoic time interval we are concerned with are available only for fragments of an island arc from Central Taimyr, which are 960 m.y. old (Vernikovsky et al., 2011) and for which the paleomagnetic pole is very close to the pole of Siberia from (Pavlov et al., 2002), and of the Kara microcontinent. This includes three paleomagnetic poles for 500, 450 and 420 Ma (Metelkin et al., 2000; Metelkin et al., 2005). It is those data that made up the basis of the presented paleotectonic reconstructions along with an extensive paleomagnetic database for the cratons of Laurentia, Baltica, Siberia and Gondwana. The paleogeographic position of the cratons is corrected (within the confidence levels for the paleomagnetic poles) according to the general model and the available global reconstructions that include the structures of the Arctic (Scotese, 1997; Lawyer et al., 2002; Golonka et al., 2003, 2006; Cocks, Torsvik, 2002, 2007). The position of those Arctida blocks that lack paleomagnetic data is reconstructed based on geological data.

Neoproterozoic-Paleozoic Evolution of the Arctida Paleocontinent and Plate Reconstructions

NASA Astrophysics Data System (ADS)

Vernikovsky, V. A.; Metelkin, D. V.; Vernikovskaya, A. E.; Matushkin, N. Y.; Lobkovsky, L. I.; Shipilov, E. V.; Scientific Team of Arctida

2011-12-01

Available data on the existence of Precambrian metamorphic complexes among the main structures of the Arctic led to the suggestion that a large continental mass existed between Laurentia, Baltica and Siberia - an Arctic continent, more often called Arctida (Zonenshain, Natapov, 1987). It is inferred that as an independent continental mass Arctida was formed after the breakup of Rodinia, and in general it can have a pre-Grenvillian (including Grenvillian) basement age. The breakup of this mass and the collision of its fragments with adjacent cratons led to the formation of heterochronous collisional systems. Arctida probably included the Kara, Novosibirsk, Alaska-Chukotka blocks, the blocks of northern Alaska and the submerged Lomonosov Ridge, small fragments of the Inuit fold belt in the north of Greenland and the Canadian archipelago, the structures of the Svalbard and maybe the Timan-Pechora plates. However the inner structure of this paleocontinent, the mutual configuration of the blocks and its evolution in the Neoproterozoic-Paleozoic is still a matter of discussion. The most accurate way of solving these issues is by using paleomagnetic data, but those are nonexistent for most of the defined blocks. Reliable paleomagnetic determinations for the Neoproterozoic-Paleozoic time interval we are concerned with are available only for fragments of an island arc from Central Taimyr, which are 960 m.y. old (Vernikovsky et al., 2011) and for which the paleomagnetic pole is very close to the pole of Siberia from (Pavlov et al., 2002), and of the Kara microcontinent. This includes three paleomagnetic poles for 500, 450 and 420 Ma (Metelkin et al., 2000; Metelkin et al., 2005). It is those data that made up the basis of the presented paleotectonic reconstructions along with an extensive paleomagnetic database for the cratons of Laurentia, Baltica, Siberia and Gondwana. The paleogeographic position of the cratons is corrected (within the confidence levels for the paleomagnetic poles) according to the general model and the available global reconstructions that include the structures of the Arctic (Scotese, 1997; Lawver et al., 2002; Golonka et al., 2003, 2006; Cocks, Torsvik, 2002, 2007). The position of those Arctida blocks that lack paleomagnetic data is reconstructed based on geological data.

Newman-Penrose constants of the Kerr-Newman metric

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

Gong Xuefei; Shang Yu; Bai Shan

The Newman-Unti formalism of the Kerr-Newman metric near future null infinity is developed, with which the Newman-Penrose constants for both the gravitational and electromagnetic fields of the Kerr-Newman metric are computed and shown to be zero. The multipole structure near future null infinity in the sense of Janis-Newman of the Kerr-Newman metric is then further studied. It is found that up to the 2{sup 4}-pole, modulo a constant dependent upon the order of the pole, these multipole moments agree with those of Geroch-Hansen multipole moments defined at spatial infinity.

Method and apparatus for assembling a permanent magnet pole assembly

DOEpatents

Carl, Jr., Ralph James; Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Scotia, NY; Dawson, Richard Nils [Voorheesville, NY; Qu, Ronghai [Clifton Park, NY; Avanesov, Mikhail Avramovich [Moscow, RU

2009-08-11

A pole assembly for a rotor, the pole assembly includes a permanent magnet pole including at least one permanent magnet block, a plurality of laminations including a pole cap mechanically coupled to the pole, and a plurality of laminations including a base plate mechanically coupled to the pole.

Ferroelectric Self-Poling, Switching, and Monoclinic Domain Configuration in BiFeO 3 Thin Films

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

Beekman, C.; Siemons, W.; Chi, M.

2016-05-23

Self-poling of ferroelectric films, i.e., a preferred, uniform direction of the ferroelectric polarization in as-grown samples is often observed yet poorly understood despite its importance for device applications. The multiferroic perovskite BiFeO 3, which crystallizes in two distinct structural polymorphs depending on applied epitaxial strain, is well known to exhibit self-poling. This study investigates the effect of self-poling on the monoclinic domain configuration and the switching properties of the two polymorphs of BiFeO 3 (R' and T') in thin films grown on LaAlO 3 substrates with slightly different La 0.3Sr 0.7MnO 3 buffer layers. Our study shows that the polarizationmore » state formed during the growth acts as “imprint” on the polarization and that switching the polarization away from this self-poled direction can only be done at the expense of the sample's monoclinic domain configuration. We observed reduction of the monoclinic domain size and found that it was largely reversible; hence, the domain size is restored when the polarization is switched back to its original orientation. This is a direct consequence of the growth taking place in the polar phase (below T c). Finally, switching the polarization away from the preferred configuration, in which defects and domain patterns synergistically minimize the system's energy, leads to a domain state with smaller (and more highly strained and distorted) monoclinic domains.« less

DISCOVERY OF A DARK AURORAL OVAL ON SATURN

NASA Technical Reports Server (NTRS)

2002-01-01

The ultraviolet image was obtained by the NASA/ESA Hubble Space Telescope with the European Faint Object Camera (FOC) on June 1992. It represents the sunlight reflected by the planet in the near UV (220 nm). * The image reveals a dark oval encircling the north magnetic pole of Saturn. This auroral oval is the first ever observed for Saturn, and its darkness is unique in the solar system (L. Ben-Jaffel, V. Leers, B. Sandel, Science, Vol. 269, p. 951, August 18, 1995). The structure represents an excess of absorption of the sunlight at 220 nm by atmospheric particles that are the product of the auroral activity itself. The large tilt of the northern pole of Saturn at the time of observation, and the almost perfect symmetry of the planet's magnetic field, made this observation unique as even the far side of the dark oval across the pole is visible! * Auroral activity is usually characterized by light emitted around the poles. The dark oval observed for Saturn is a STUNNING VISUAL PROOF that transport of energy and charged particles from the magnetosphere to the atmosphere of the planet at high latitudes induces an auroral activity that not only produces auroral LIGHT but also UV-DARK material near the poles: auroral electrons are probably initiating hydrocarbon polymer formation in these regions. Credits: L. Ben Jaffel, Institut d'Astrophysique de Paris-CNRS, France, B. Sandel (Univ. of Arizona), NASA/ESA, and Science (magazine).

Exceptional Arctic warmth of early winter 2016 and attribution to global warming

NASA Astrophysics Data System (ADS)

van Oldenborgh, Geert Jan; Macias-Fauria, Marc; King, Andrew; Uhe, Peter; Philip, Sjoukje; Kew, Sarah; Karoly, David; Otto, Friederike; Allen, Myles; Cullen, Heidi

2017-04-01

The dark polar winters usually sport the coldest extremes on Earth, however this winter, the North Pole and the surrounding Arctic region have experienced record high temperatures in November and December, with daily means reaching 15 °C (27 °F) above normal and a November monthly mean that was 13 °C (23 °F) above normal on the pole. November also saw a brief retreat of sea-ice that was virtually unprecedented in nearly 40 years of satellite records, followed by a record low in November sea ice area since 1850. Unlike the Antarctic, Arctic lands are inhabited and their socio-economic systems are greatly affected by the impacts of extreme and unprecedented sea ice dynamics and temperatures, such as for example, the timing of marine mammal migrations, and refreezing rain on snow that prevents reindeer from feeding. Here we report on our multi-method rapid attribution analysis of North Pole November-December temperatures. To quantify the rarity of the event, we computed the November-December averaged temperature around the North Pole (80-90 °N) in the (short but North-pole covering) ERA-interim reanalysis. To put the event in context of natural variability, we use a longer and closely related time series based on the northern most meteorological observations on land (70-80 °N). This allows for a reconstruction of Arctic temperatures back to about 1900. We also perform a multi-method analysis of North Pole temperatures with two sets of climate models: the CMIP5 multi-model ensemble, and a large ensemble of model runs in the so-called Weather@Home project. Physical mechanisms that are responsible for temperature and sea ice variability in the North Pole region are also discussed. The observations and the bias-corrected CMIP5 ensemble point to a return period of about 50 to 200 years in the present climate, i.e., the probability of such an extreme is about 0.5% to 2% every year, with a large uncertainty. The observations show that November-December temperatures have risen on the North Pole, modulated by decadal North Atlantic variability. For all phases of this variability, a warm event like the one of this winter would have been extremely unlikely in the climate of a century ago. Both sets of models also give very comparable results and show that the bulk of the arctic temperature increase is due to anthropogenic emissions. This also holds for the warm extremes caused by the type of circulation present in the early winter of 2016.

Round timbers and ties

Treesearch

Ronald W. Wolfe

1999-01-01

Round timbers and ties represent some of the most efficient uses of our forest resources. They require a minimum of processing between harvesting the tree and marketing the structural commodity. Poles and piles are debarked or peeled, seasoned, and often treated with preservative prior to use as structural members. Construction logs are usually shaped to facilitate...

Cleopatra's Bedroom oblique with picture tube wall along walkway. Structure ...

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

Cleopatra's Bedroom oblique with picture tube wall along walkway. Structure is made solely of amber colored bottles. Roof supported by telephone poles. Areas of bottle wall above window opening collapsed in the 1994 Northridge earthquake. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

Piezoelectric paints as one approach to smart structural materials with health-monitoring capabilities

NASA Astrophysics Data System (ADS)

Egusa, Shigenori; Iwasawa, Naozumi

1998-08-01

Piezoelectric paints have a potential to change a conventional structural material into an intelligent material system with health-monitoring capabilities such as vibration sensing and damage detection. Such paints were prepared using lead zirconate titanate (PZT) ceramic powder as a pigment and epoxy resin as a binder. The obtained paints were coated on aluminum test specimens, and were cured at room temperature or at 150 0964-1726/7/4/002/img5, thus forming the paint films having different thicknesses of 25-300 0964-1726/7/4/002/img6. These films were then poled at room temperature, and were evaluated with regard to the sensitivities as vibration and acoustic emission sensors in the frequency ranges of 0-250 Hz and 0-1.0 MHz, respectively. This paper mainly describes the effects of the film thickness and the cure temperature on the poling behavior of the PZT/epoxy paint film. This paper describes also the application of the paint film as a vibration modal sensor integrated into a structural material.

Fabrication and analysis of radiofrequency MEMS series capacitive single-pole double-throw switch

NASA Astrophysics Data System (ADS)

Bansal, Deepak; Bajpai, Anuroop; Kumar, Prem; Kaur, Maninder; Rangra, Kamaljit

2016-10-01

A compact radiofrequency (RF) MEMS single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed. The critical process parameters are analyzed to improve the fabrication process. A technique of cold-hot thermal shock for lift-off method is explored. The residual stress in the structure is quantified by lancet test structures that come out to be 51 MPa. Effect of residual stress on actuation voltage is explored, which changes its value from 24 to 22 V. Resonance frequency and switching speed of the switch are 11 kHz and 44 μs, respectively, measured using laser Doppler vibrometer. Measured bandwidth of the SPDT switch is 20 GHz (5 to 25 GHz), which is verified with finite element method simulations in high frequency structure simulator©; and an equivalent LCR circuit in advanced design system©;. Insertion loss of the switch lies in -0.1 to -0.5 dB with isolation better than -20 dB for the above-mentioned bandwidth.

Experimental and Theoretical Research on the Compression Performance of CFRP Sheet Confined GFRP Short Pipe

PubMed Central

Zhao, Qilin; Chen, Li; Shao, Guojian

2014-01-01

The axial compressive strength of unidirectional FRP made by pultrusion is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. A theoretical iterative calculation approach was suggested to predict the ultimate axial compressive stress of the combined structure and analyze the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure. In this paper, the experimental and theoretical research on the CFRP sheet confined GFRP short pole was extended to the CFRP sheet confined GFRP short pipe, namely, a hollow section pole. Experiment shows that the bearing capacity of the GFRP short pipe can also be heightened obviously by confining CFRP sheet. The theoretical iterative calculation approach in the previous paper is amended to predict the ultimate axial compressive stress of the CFRP sheet confined GFRP short pipe, of which the results agree with the experiment. Lastly the influences of geometrical parameters on the new combined structure are analyzed. PMID:24672288

Design, simulation and testing of a novel radial multi-pole multi-layer magnetorheological brake

NASA Astrophysics Data System (ADS)

Wu, Jie; Li, Hua; Jiang, Xuezheng; Yao, Jin

2018-02-01

This paper deals with design, simulation and experimental testing of a novel radial multi-pole multi-layer magnetorheological (MR) brake. This MR brake has an innovative structural design with superposition principle of two magnetic fields generated by the inner coils and the outer coils. The MR brake has several media layers of magnetorheological (MR) fluid located between the inner coils and the outer coils, and it can provide higher torque and higher torque density than conventional single-disk or multi-disk or multi-pole single-layer MR brakes can. In this paper, a brief introduction to the structure of the proposed MR brake was given first. Then, theoretical analysis of the magnetic circuit and the braking torque was conducted. In addition, a 3D electromagnetic model of the MR brake was developed to simulate and examine the magnetic flux intensity and corresponding braking torque. A prototype of the brake was fabricated and several tests were carried out to validate its torque capacity. The results show that the proposed MR brake can produce a maximum braking torque of 133 N m and achieve a high torque density of 25.0 kN m-2, a high torque range of 42 and a high torque-to-power ratio of 0.95 N m W-1.

The scaffolding and signaling functions of a localization factor impact polar development

PubMed Central

Curtis, Patrick D.; Quardokus, Ellen M.; Lawler, Melanie L.; Guo, Xiaoyun; Klein, David; Chen, Joseph C.; Arnold, Randy J.; Brun, Yves V.

2012-01-01

SUMMARY In the differentiating alphaproteobacterium Caulobacter crescentus, organelle synthesis at cell poles is critical to forming different progeny after cell division. Coordination of polar organelle synthesis, including pili and holdfast, and flagellum ejection, is mediated in part by the scaffolding protein PodJ. At the time of cell division, PodJ undergoes regulated processing to a short form that persists at the flagellar pole of swarmer cells. This study analyzes how PodJ’s role in structural and signaling protein localization impacts organelle synthesis. A PodJ mutant with an internal deletion exhibits reduced sensitivity to pili-tropic phage ΦCbK, resulting from reduced pilA gene expression, which can be linked to altered signaling protein localization. The phage sensitivity defect of a ΔpodJ mutant can be partially suppressed by ectopic pilA expression. Induction of PodJ processing, by manipulation of podJ itself or controlled perP expression, resulted in decreased pilus biogenesis and, when coupled with a podJ mutation that reduced pilA expression, led to complete loss of phage sensitivity. As a whole, the results show that PodJ’s scaffolding role for structural and signaling proteins both contribute to flagellar pole organelle development. PMID:22512778

Big George to Carter Mountain 115-kV transmission line project, Park and Hot Springs Counties, Wyoming. Environmental Assessment

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

Not Available

1994-02-01

The Western Area Power Administration (Western) is proposing to rebuild, operate, and maintain a 115-kilovolt (kV) transmission line between the Big George and Carter Mountain Substations in northwest Wyoming (Park and Hot Springs Counties). This environmental assessment (EA) was prepared in compliance with the National Environmental Policy Act (NEPA) and the regulations of the Council on Environmental Quality (CEQ) and the Department of Energy (DOE). The existing Big George to Carter Mountain 69-kV transmission line was constructed in 1941 by the US Department of Interior, Bureau of Reclamation, with 1/0 copper conductor on wood-pole H-frame structures without an overhead groundmore » wire. The line should be replaced because of the deteriorated condition of the wood-pole H-frame structures. Because the line lacks an overhead ground wire, it is subject to numerous outages caused by lightning. The line will be 54 years old in 1995, which is the target date for line replacement. The normal service life of a wood-pole line is 45 years. Under the No Action Alternative, no new transmission lines would be built in the project area. The existing 69-kV transmission line would continue to operate with routine maintenance, with no provisions made for replacement.« less

Yamato: Bringing the Moon to the Earth ... Again

NASA Technical Reports Server (NTRS)

Lam, King; Martinelli, Scott; Patel, Neal; Powell, David; Smith, Brandon

2008-01-01

The Yamato mission to the lunar South Pole-Aitken Basin returns samples that enable dating of lunar formation and the lunar bombardment period. The design of the Yamato mission is based on a systems engineering process which takes an advanced consideration of cost and mission risk to give the mission a high probability of success.

Analysis of Stationary, Photovoltaic-based Surface Power System Designs at the Lunar South Pole

NASA Technical Reports Server (NTRS)

Freeh, Joshua E.

2009-01-01

Combinations of solar arrays and either batteries or regenerative fuel cells are analyzed for a surface power system module at the lunar south pole. The systems are required to produce 5 kW of net electrical power in sunlight and 2 kW of net electrical power during lunar night periods for a 10-year period between 2020 and 2030. Systems-level models for energy conservation, performance, degradation, and mass are used to compare to various systems. The sensitivities of important and/or uncertain variables including battery specific energy, fuel cell operating voltage, and DC-DC converter efficiency are compared to better understand the system. Switching unit efficiency, battery specific energy, and fuel cell operating voltage appear to be important system-level variables for this system. With reasonably sized solar arrays, the regenerative fuel cell system has significantly lower mass than the battery system based on the requirements and assumptions made herein. The total operational time is estimated at about 10,000 hours in battery discharge/fuel cell mode and about 4,000 and 8,000 hours for the battery charge and electrolyzer modes, respectively. The estimated number of significant depth-of-discharge cycles for either energy storage system is less than 100 for the 10-year period.

A continuous-wave, widely tunable, intra-cavity, singly resonant, magnesium-doped, periodically poled lithium niobate optical parametric oscillator

NASA Astrophysics Data System (ADS)

Li, Z. P.; Duan, Y. M.; Wu, K. R.; Zhang, G.; Zhu, H. Y.; Wang, X. L.; Chen, Y. H.; Xue, Z. Q.; Lin, Q.; Song, G. C.; Su, H.

2013-05-01

We report a continuous-wave (CW), intra-cavity singly resonant optical parametric oscillator (OPO), based on periodically poled MgO:LiNbO3 pumped by a diode-end-pumped CW Nd:YVO4 laser, and calculate the gain of optical parametric amplification as a function of pump beam waist (at 1064 nm) in the singly resonant OPO (SRO) cavity, to balance the mode-matching and the intensity for the higher gain of a signal wave in the operation of the SRO. In order to achieve maximum gain, we use a convex lens to limit the 1064 nm beam waist. In the experiment, a tunable signal output from 1492 to 1614 nm and an idler output from 3122 to 3709 nm are obtained. For an 808 nm pump power of 11.5 W, a maximum signal output power of up to 2.48 W at 1586 nm and an idler output power of 1.1 W at 3232 nm are achieved with a total optical-to-optical conversion efficiency of 31%.

Femtosecond OPO based on MgO:PPLN synchronously pumped by a 532 nm fiber laser

NASA Astrophysics Data System (ADS)

Cao, Jianjun; Shen, Dongyi; Zheng, Yuanlin; Feng, Yaming; Kong, Yan; Wan, Wenjie

2017-05-01

With the rapid progress in fiber technologies, femtosecond fiber lasers, which are compact, cost-effective and stable, have been developed and are commercially available. Studies of optical parametric oscillators (OPOs) pumped by this type of laser are demanding. Here we report a femtosecond optical parametric oscillator (OPO) at 79.6 MHz repetition rate based on MgO-doped periodically poled LiNbO3 (MgO:PPLN), synchronously pumped by the integrated second harmonic radiation of a femtosecond fiber laser at 532 nm. The signal delivered by the single resonant OPO is continuously tunable from 757 to 797 nm by tuning the crystal temperature in a poling period of 7.7 μ \\text{m} . The output signal shows good beam quality in TEM00 mode profile with pulse duration of 206 fs at 771 nm. Maximum output signal power of 71 mW is obtained for a pump power of 763 mW and a low pumping threshold of 210 mW is measured. Moreover, grating tuning and cavity length tuning of the signal wavelength are also investigated.

Sub-nanosecond periodically poled lithium niobate optical parametric generator and amplifier pumped by an actively Q-switched diode-pumped Nd:YAG microlaser

NASA Astrophysics Data System (ADS)

Liu, L.; Wang, H. Y.; Ning, Y.; Shen, C.; Si, L.; Yang, Y.; Bao, Q. L.; Ren, G.

2017-05-01

A sub-nanosecond seeded optical parametric generator (OPG) based on magnesium oxide-doped periodically poled lithium niobate (MgO:PPLN) crystal is presented. Pumped by an actively Q-switched diode-pumped 1 kHz, 1064 nm, Nd:YAG microlaser and seeded with a low power distributed feedback (DFB) diode continuous-wave (CW) laser, the OPG generated an output energy of 41.4 µJ and 681 ps pulse duration for the signal at 1652.4 nm, achieving a quantum conversion efficiency of 61.2% and a slope efficiency of 41.8%. Signal tuning was achieved from 1651.0 to 1652.4 nm by tuning the seed-laser current. The FWHM of the signal spectrum was approximately from 35 nm to 0.5 nm by injection seed laser. The SHG doubled the frequency of OPG signal to produce a output energy of 12 µJ with the energy conversion efficiency of 29.0% and tunanble wavelength near 826 nm.

Seasonal Changes in Titan's Surface Temperatures

NASA Technical Reports Server (NTRS)

Jennins, Donald E.; Cottini, V.; Nixon, C. A.; Flasar, F. M.; Kunde, V. G.; Samuelson, R. E.; Romani, P. N.; Hesman, B. E.; Carlson, R. C.; Gorius, N. J. P.;

160-Gb/s all-optical phase-transparent wavelength conversion through cascaded SFG-DFG in a broadband linear-chirped PPLN waveguide.

PubMed

Lu, Guo-Wei; Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya; Miyazaki, Tetsuya; Ito, Hiromasa

2010-03-15

We experimentally demonstrated ultra-fast phase-transparent wavelength conversion using cascaded sum- and difference-frequency generation (cSFG-DFG) in linear-chirped periodically poled lithium niobate (PPLN). Error-free wavelength conversion of a 160-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) signal was successfully achieved. Thanks to the enhanced conversion bandwidth in the PPLN with linear-chirped periods, no optical equalizer was required to compensate the spectrum distortion after conversion, unlike a previous demonstration of 160-Gb/s RZ on-off keying (OOK) using fixed-period PPLN.

COMPARISON OF FUNCTIONAL ACTIVITIES ON STRUCTURAL CHANGES OF THE INFERIOR PATELLAR POLE

PubMed Central

Wallmann, Harvey; Stalcup, Patrick; DiTommaso, Katie

2017-01-01

Background It is well known that eccentric and concentric exercise produce varied amounts of stress on the connective tissues. Diagnostic ultrasound has been used to measure these structural changes by observing fascicle length, angle, and thickness; however, there is a lack of evidence comparing the structural changes as it relates to eccentric, concentric, and stretching protocols. Purpose The purpose of this study was to compare the acute effects of static stretching, eccentric, concentric, and a combination of eccentric/concentric exercises on structural changes of the muscle tendon unit at the inferior patellar pole utilizing the diagnostic ultrasound. Study Design A repeated measures 2 × 4 within factorial study design with repeated measures on both factors was used to determine the differences in patellar tendon thickness within and between groups. Methods Forty-seven healthy subjects were screened for any lower extremity deficits or orthopaedic pathology. Forty-four (N=44) subjects completed all four protocols; the attrition was due to injuries to the lower extremity, occurring unrelated to the study. A baseline measurement of the anterior inferior patellar tendon was performed with the diagnostic ultrasound prior to each participant completing one of the four interventions per week over a four-week period. Interventions completed by each participant included static stretching, concentric, eccentric, and combined concentric and eccentric exercises. Immediately following each intervention, a post-intervention inferior patellar tendon measurement was recorded using the diagnostic ultrasound. Results Significant differences in anterior to posterior tendon thickness of the inferior patellar tendon were observed between pre (4.983 ± 0.041mm) and post (5.198 ± 0.055mm) measurements (p<0.0005) for the main effect of time. However, no differences in tendon thickness were noted comparing each intervention to one another (p=0.351). Conclusion Differences in tendon thickness were noted acutely for pre- to post measurements across all interventions. Further research is needed to determine if differences in tendon thickness exist with a longer duration of exercise over time and with different types of intervention. PMID:29234561

The Multiplicity of the Mitotic Centers and the Time-Course of Their Duplication and Separation

PubMed Central

Mazia, Daniel; Harris, Patricia J.; Bibring, Thomas

1960-01-01

In this study, the reproduction of the mitotic centers in the eggs of a sea urchin, Strongylocentrotus purpuratus and a sand dollar Dendraster excentricus has been studied by means of experimental designs that do not depend on the actual visualization of centrioles. The centers are defined in operational terms as potential poles. Blockage of mitosis by mercaptoethanol, it was found, inhibits the duplication of the centers, but does not inhibit the splitting and separation of centers that have already duplicated and thus potential poles could be realized as actual poles in multipolar divisions. At all times, the center is at least a duplex structure; that is, it contains two potential poles. The actual duplication process is the earliest event in a given mitotic cycle, taking place at very early interphase or in late telophase of the previous division. The splitting of the centers following duplication is a distinct process, dissociable from the duplication as such. Duplication and splitting normally occur at about the same time in the mitotic cycle, with a precession of the former. That is, as the two members of a pair of "old" centers split, each one gives rise to a new one, which remains associated with it until the next phase of splitting and duplication occurs. The results are consistent with what is termed a "generative" model of the self-reproduction of an intracellular body. According to this, the body does not immediately produce a full-fledged copy of itself, with simultaneous fission, but the primary duplication event involves only a part of the parent structure. This gives rise to a "germ" or "seed" which then grows to be equivalent to the parent body, and finally splits from it. PMID:19866563

Numerical analysis of right-half plane zeros for a single-link manipulator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Girvin, Douglas Lynn

1992-01-01

The purpose of this research is to further develop an understanding of how nonminimum phase zero location is affected by structural link design. As the demand for light-weight robots that can operate in a large workspace increases, the structural flexibility of the links become more of an issue in controls problems. When the objective is to accurately position the tip while the robot is actuated at the base, the system is nonminimum phase. One important characteristic of nonminimum phase systems is system zeros in the right half of the Laplace plane. The ability to pick the location of these nonminimum phase zeros would give the designer a new freedom similar to pole placement. The research targets a single-link manipulator operating in the horizontal plane and modeled as a Euler-Bernoulli beam with pinned-free end conditions. Using transfer matrix theory, one can consider link designs that have variable cross-sections along the length of the beam. A FORTRAN program was developed to determine the location of poles and zeros given the system model. The program was used to confirm previous research on nonminimum phase systems, and develop a relationship for designing linearly tapered links. The method allows the designer to choose the location of the first pole and zero and then defines the appropriate taper to match the desired locations. With the pole and zero location fixes, the designer can independently change the link's moment of inertia about its axis of rotation by adjusting the height of the beam. These results can be applied to inverse dynamic algorithms currently under development at Georgia Tech.

A compensated multi-pole linear ion trap mercury frequency standard for ultra-stable timekeeping.

PubMed

Burt, Eric A; Diener, William A; Tjoelker, Robert L

2008-12-01

The multi-pole linear ion trap frequency standard (LITS) being developed at the Jet Propulsion Laboratory (JPL) has demonstrated excellent short- and long-term stability. The technology has now demonstrated long-term field operation providing a new capability for timekeeping standards. Recently implemented enhancements have resulted in a record line Q of 5 x 10(12) for a room temperature microwave atomic transition and a short-term fractional frequency stability of 5 x 10(-14)/tau(1/2). A scheme for compensating the second order Doppler shift has led to a reduction of the combined sensitivity to the primary LITS systematic effects below 5 x 10(-17) fractional frequency. Initial comparisons to JPL's cesium fountain clock show a systematic floor of less than 2 x 10(-16). The compensated multi-pole LITS at JPL was operated continuously and unattended for a 9-mo period from October 2006 to July 2007. During that time it was used as the frequency reference for the JPL geodetic receiver known as JPLT, enabling comparisons to any clock used as a reference for an International GNSS Service (IGS) site. Comparisons with the laser-cooled primary frequency standards that reported to the Bureau International des Poids et Mesures (BIPM) over this period show a frequency deviation less than 2.7 x 10(-17)/day. In the capacity of a stand-alone ultra-stable flywheel, such a standard could be invaluable for long-term timekeeping applications in metrology labs while its methodology and robustness make it ideal for space applications as well.

Predicting Interactions between Common Dolphins and the Pole-and-Line Tuna Fishery in the Azores

PubMed Central

Cruz, Maria João; Menezes, Gui; Machete, Miguel; Silva, Mónica A.

2016-01-01

Common dolphins (Delphinus delphis) are responsible for the large majority of interactions with the pole-and-line tuna fishery in the Azores but the underlying drivers remain poorly understood. In this study we investigate the influence of various environmental and fisheries-related factors in promoting the interaction of common dolphins with this fishery and estimate the resultant catch losses. We analysed 15 years of fishery and cetacean interaction data (1998–2012) collected by observers placed aboard tuna fishing vessels. Dolphins interacted in less than 3% of the fishing events observed during the study period. The probability of dolphin interaction varied significantly between years with no evident trend over time. Generalized additive modeling results suggest that fishing duration, sea surface temperature and prey abundance in the region were the most important factors explaining common dolphin interaction. Dolphin interaction had no impact on the catches of albacore, skipjack and yellowfin tuna but resulted in significantly lower catches of bigeye tuna, with a predicted median annual loss of 13.5% in the number of fish captured. However, impact on bigeye catches varied considerably both by year and fishing area. Our work shows that rates of common dolphin interaction with the pole-and-line tuna fishery in the Azores are low and showed no signs of increase over the study period. Although overall economic impact was low, the interaction may lead to significant losses in some years. These findings emphasize the need for continued monitoring and for further research into the consequences and economic viability of potential mitigation measures. PMID:27851763

Predicting Interactions between Common Dolphins and the Pole-and-Line Tuna Fishery in the Azores.

PubMed

Cruz, Maria João; Menezes, Gui; Machete, Miguel; Silva, Mónica A

2016-01-01

Common dolphins (Delphinus delphis) are responsible for the large majority of interactions with the pole-and-line tuna fishery in the Azores but the underlying drivers remain poorly understood. In this study we investigate the influence of various environmental and fisheries-related factors in promoting the interaction of common dolphins with this fishery and estimate the resultant catch losses. We analysed 15 years of fishery and cetacean interaction data (1998-2012) collected by observers placed aboard tuna fishing vessels. Dolphins interacted in less than 3% of the fishing events observed during the study period. The probability of dolphin interaction varied significantly between years with no evident trend over time. Generalized additive modeling results suggest that fishing duration, sea surface temperature and prey abundance in the region were the most important factors explaining common dolphin interaction. Dolphin interaction had no impact on the catches of albacore, skipjack and yellowfin tuna but resulted in significantly lower catches of bigeye tuna, with a predicted median annual loss of 13.5% in the number of fish captured. However, impact on bigeye catches varied considerably both by year and fishing area. Our work shows that rates of common dolphin interaction with the pole-and-line tuna fishery in the Azores are low and showed no signs of increase over the study period. Although overall economic impact was low, the interaction may lead to significant losses in some years. These findings emphasize the need for continued monitoring and for further research into the consequences and economic viability of potential mitigation measures.

Nova V2214 Ophiuchi 1988 - A magnetic nova inside the period gap

NASA Technical Reports Server (NTRS)

Baptista, R.; Jablonski, F. J.; Cieslinski, D.; Steiner, J. E.

1993-01-01

The discovery of a coherent photometric modulation in Nova Oph 1988 with period 0.117515 +/- 0.000002 d, which is associated with the orbital period of the underlying binary, is reported. On the basis of photometric observations, it is concluded that Nova V2214 Oph 1988 is a magnetic nova with an orbital period inside the period gap. The inclusion of this system in the statistics of novae suggests that there is no period gap for novae and that there is a clear correlation between the occurrence of novae with short orbital periods and the presence of magnetic white dwarfs. It is suggested that funneling of the accretion flow onto the magnetic poles favors the conditions for a thermonuclear runaway, increasing the frequency of eruptions for magnetic systems.

High performance hybrid magnetic structure for biotechnology applications

DOEpatents

Humphries, David E [El Cerrito, CA; Pollard, Martin J [El Cerrito, CA; Elkin, Christopher J [San Ramon, CA

2009-02-03

The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetic or magnetizable molecular structures and targets. Also disclosed are further improvements to aspects of the hybrid magnetic structure, including additional elements and for adapting the use of the hybrid magnetic structure for use in biotechnology and high throughput processes.

Evidence for Surface and Subsurface Ice Inside Micro Cold-Traps on Mercury's North Pole

NASA Technical Reports Server (NTRS)

Rubanenko, L.; Mazarico, E.; Neumann, G. A.; Paige, D. A.

2017-01-01

The small obliquity of Mercury causes topographic depressions located near its poles to cast persistent shadows. Many [1, 9, 15] have shown these permanently shadowed regions (PSRs) may trap water ice for geologic time periods inside cold-traps. More recently, direct evidence for the presence of water ice deposits inside craters was remotely sensed in RADAR [5] and visible imagery [3]. Albedo measurements (reflectence at 1064 nm) obtained by the MErcury Space ENviroment GEochemistry and Ranging Laser Altimeter (MLA) found unusually bright and dark areas next to Mercury's north pole [7]. Using a thermal illumination model, Paige et al. [8] found the bright deposits are correlated with surface cold-traps, and the dark deposits are correlated with subsurface cold-traps. They suggested these anomalous deposits were brought to the surface by comets and were processed by the magnetospheric radiation flux, removing hydrogen and mixing C-N-O-S atoms to form a variety of molecules which will darken with time. Here we use a thermal illumination model to find the link between the cold-trap area fraction of a rough surface and its albedo. Using this link and the measurements obtained by MESSENGER we derive a surface and a subsurface ice distribution map on Mercury's north pole below the MESSENGER spatial resolution, approximately 500 m. We find a large fraction of the polar ice on Mercury resides inside micro cold-traps (of scales 10 - 100 m) distributed along the inter-crater terrain.

[Kinematics and ultrastructure of plasmic factor regions in the egg of Wachtliella persicariae L. (Diptera) : II. The behaviour of ooplasmic partial systems after centrifugation of eggs in the stage of four cleavage nuclei].

PubMed

Wolf, Rainer

1969-03-01

Kinematics and ultrastructure of centrifuged and untreated eggs fromWachtliella persicariae were investigated for the micromorphological properties of ooplasmic factor regions and their role in early developmental processes by means of time-lapse motion pictures and electron microscopic analysis (see part I).After centrifugation the eggs show up to five different layers, among them a pole of fatty yolk with lipid droplets, a region of clear plasm (rich in ground plasm) which itself may become subdivided into a centripetal region with nuclei and endoplasmic reticulum, followed by a centrifugal part with mitochondria and ribosomes, another region containing orange clods of proteid yolk and finally a cup of glycogen. Displacement of pole plasm from the posterior pole always is accompanied by dislocation of the basophilic oosome material contained therein. At sufficient r.p.m. both of them enter the centripetal area of clear plasm. Structures of "di-polar density" type are orientated by centrifugation. The initial phase till the centrifuge reaches its final r.p.m. may act decicively upon the site of certain egg components after centrifugation as upon the nuclei, and thus may essentially influence the experimental results. In case centrifugation coincides with certain dividing phases of energides, the nuclear envelope becomes fragmented. The fragments then may appear piled up to form annulated membranes which have been recognized as pathological structures in centrifuged eggs. Besides lamellar cytosomes are often found. In centrifuged as well as in untreated eggs the nuclear envelope either consists of two layers as usual or may be of the complex multi-layered type (see part I). As for the movement of nuclei, the possible role of the complex nuclear envelope is not yet clear. The pigment halo of cleavage nuclei does not play an active part in nuclear migration. In centrifuged eggs yolk nuclei are of the usual type i.e. either roundish, horse-shoe-shaped or multi-lobed. They mostly appear in parts of the entoplasm which are poor in yolk. A surrounding rich in yolk does not seem to be essential for transforming normal cleavage nuclei into vitellophagues. For their changing into the multi-lobed type yolk nuclei must be surrounded by a sufficient amount of ground plasm.Pole cells have been found in the posterior pole region only. Their formation requires an abundant amount of ground plasm, the presence of cleavage energides, as well as pole plasm and oosome material, if not either of the two latter systems. Since in centrifuged eggs pole plasm and basophilic oosome material are always shifted together into the region of clear plasm, contrary to the opinion of other authors (p. 42; part I, p. 124) the technique of centrifugation does not permit any decision as to which of both ooplasmic systems controls the karyotic differentiation of the germ line or the formation of pole cells, respectively, or whether both systems are essential to promote these processes.The oolemma may also become invaginated to form cell membranes when no nuclei are present ("pseudoblastoderm"), the formation occurring in regions with sufficient amounts of ground plasm only. For that reason the formation of pole cells is restricted to the posterior pole rich in ground plasm, whereas blastoderm cells exclusively occur in the area of preblastoderm plasm. The ground plasm plays a decisive part in the dynamics of cell membrane formation. As for blastoderm cells, the nuclei seem to be necessary only to control their regular shape. In contradiction to the opinion of other authors (p. 42, part I, p. 124), the periplasm of young eggs cannot range among the essential prerequisites of blastoderm formation. During centrifugation it does not stay at the surface of the egg poles where nevertheless a blastoderm may be formed. Yet blastoderm formation is only possible if, in spite of the compact condition of polar yolk material, the egg poles become covered with preblastoderm plasm from the region of clear plasm, rich in ground plasm, and thus replacing sufficient amounts of periplasm and ground plasm shifted by centrifugation.

Comparative analysis of different weight matrices in subspace system identification for structural health monitoring

NASA Astrophysics Data System (ADS)

Shokravi, H.; Bakhary, NH

2017-11-01

Subspace System Identification (SSI) is considered as one of the most reliable tools for identification of system parameters. Performance of a SSI scheme is considerably affected by the structure of the associated identification algorithm. Weight matrix is a variable in SSI that is used to reduce the dimensionality of the state-space equation. Generally one of the weight matrices of Principle Component (PC), Unweighted Principle Component (UPC) and Canonical Variate Analysis (CVA) are used in the structure of a SSI algorithm. An increasing number of studies in the field of structural health monitoring are using SSI for damage identification. However, studies that evaluate the performance of the weight matrices particularly in association with accuracy, noise resistance, and time complexity properties are very limited. In this study, the accuracy, noise-robustness, and time-efficiency of the weight matrices are compared using different qualitative and quantitative metrics. Three evaluation metrics of pole analysis, fit values and elapsed time are used in the assessment process. A numerical model of a mass-spring-dashpot and operational data is used in this research paper. It is observed that the principal components obtained using PC algorithms are more robust against noise uncertainty and give more stable results for the pole distribution. Furthermore, higher estimation accuracy is achieved using UPC algorithm. CVA had the worst performance for pole analysis and time efficiency analysis. The superior performance of the UPC algorithm in the elapsed time is attributed to using unit weight matrices. The obtained results demonstrated that the process of reducing dimensionality in CVA and PC has not enhanced the time efficiency but yield an improved modal identification in PC.

Robustification and Optimization in Repetitive Control For Minimum Phase and Non-Minimum Phase Systems

NASA Astrophysics Data System (ADS)

Prasitmeeboon, Pitcha

Repetitive control (RC) is a control method that specifically aims to converge to zero tracking error of a control systems that execute a periodic command or have periodic disturbances of known period. It uses the error of one period back to adjust the command in the present period. In theory, RC can completely eliminate periodic disturbance effects. RC has applications in many fields such as high-precision manufacturing in robotics, computer disk drives, and active vibration isolation in spacecraft. The first topic treated in this dissertation develops several simple RC design methods that are somewhat analogous to PID controller design in classical control. From the early days of digital control, emulation methods were developed based on a Forward Rule, a Backward Rule, Tustin's Formula, a modification using prewarping, and a pole-zero mapping method. These allowed one to convert a candidate controller design to discrete time in a simple way. We investigate to what extent they can be used to simplify RC design. A particular design is developed from modification of the pole-zero mapping rules, which is simple and sheds light on the robustness of repetitive control designs. RC convergence requires less than 90 degree model phase error at all frequencies up to Nyquist. A zero-phase cutoff filter is normally used to robustify to high frequency model error when this limit is exceeded. The result is stabilization at the expense of failure to cancel errors above the cutoff. The second topic investigates a series of methods to use data to make real time updates of the frequency response model, allowing one to increase or eliminate the frequency cutoff. These include the use of a moving window employing a recursive discrete Fourier transform (DFT), and use of a real time projection algorithm from adaptive control for each frequency. The results can be used directly to make repetitive control corrections that cancel each error frequency, or they can be used to update a repetitive control FIR compensator. The aim is to reduce the final error level by using real time frequency response model updates to successively increase the cutoff frequency, each time creating the improved model needed to produce convergence zero error up to the higher cutoff. Non-minimum phase systems present a difficult design challenge to the sister field of Iterative Learning Control. The third topic investigates to what extent the same challenges appear in RC. One challenge is that the intrinsic non-minimum phase zero mapped from continuous time is close to the pole of repetitive controller at +1 creating behavior similar to pole-zero cancellation. The near pole-zero cancellation causes slow learning at DC and low frequencies. The Min-Max cost function over the learning rate is presented. The Min-Max can be reformulated as a Quadratically Constrained Linear Programming problem. This approach is shown to be an RC design approach that addresses the main challenge of non-minimum phase systems to have a reasonable learning rate at DC. Although it was illustrated that using the Min-Max objective improves learning at DC and low frequencies compared to other designs, the method requires model accuracy at high frequencies. In the real world, models usually have error at high frequencies. The fourth topic addresses how one can merge the quadratic penalty to the Min-Max cost function to increase robustness at high frequencies. The topic also considers limiting the Min-Max optimization to some frequencies interval and applying an FIR zero-phase low-pass filter to cutoff the learning for frequencies above that interval.

Observations and statistical simulations of a proposed solar cycle/QBO/weather relationship

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

Baldwin, M.P.; Dunkerton, T.J.

1989-08-01

The 10.7 cm solar flux is observed to be highly correlated with north pole stratospheric temperatures when partitioned according to the phase of the equatorial stratospheric winds (the quasi-biennial oscillation, or QBO). The authors supplement observations with calculations showing that temperatures over most of the northern hemisphere are highly correlated or anticorrelated with north pole temperatures. The observed spatial pattern of solar cycle correlations at high latitudes is shown to be not unique to the solar cycle. The authors present results, similar to the observed solar cycle correlations, with simulated harmonics of various periods replacing the solar cycle. These calculationsmore » demonstrate the correlations at least as high as those for the solar cycle results may be obtained using simulated harmonics.« less

Paleomagnetic study of the northern Ford Ranges, western Marie Byrd Land, West Antarctica: Motion between West and East Antarctica

NASA Astrophysics Data System (ADS)

Luyendyk, Bruce; Cisowski, Stan; Smith, Christine; Richard, Steve; Kimbrough, David

1996-02-01

A paleomagnetic study of Paleozoic and Mesozoic crystalline rocks in the northern Ford Ranges of Marie Byrd Land, West Antarctica, has determined a middle Cretaceous (circa 100 Ma) paleomagnetic pole and provided constraints on possible clockwise rotation of these ranges and on the rifting of east Gondwana. The 40Ar/39Ar thermochronology data from the Fosdick Mountains record a period of rapid cooling from ˜700°C beginning at ˜100 Ma. We relate this to extension, intrusion, and uplift associated with the beginning of rifting between Campbell Plateau and Marie Byrd Land. All rocks from the Fosdick and Chester Mountains are normally polarized. We interpret thermochronology and paleomagnetic data to infer that the region was extensively remagnetized in middle Cretaceous time. Inclinations in samples from the Chester Mountains are less steep than those from the Fosdick Mountains, which we interpret as ˜25° of south tilting of the Chesters. We interpret cooling age data for the time of magnetization to infer that the tilting began after 105 Ma and ended prior to 103 Ma. We further interpret this as constraining the beginning of extension between the Campbell Plateau and western Marie Byrd Land to the interval 105 to 103 Ma. Virtual geomagnetic poles from samples of Early Carboniferous age granodiorite from the western Phillips Mountains lie on the late Paleozoic apparent polar wander path for Australia transferred to Antarctica. Directions from 29 sites in the central and eastern Phillips and Fosdick Mountains give a Middle Cretaceous paleomagnetic pole at 222.3° E, 70.5° S (A95 6.1°, KAPPA 20.0). This pole is indistinguishable from other Middle Cretaceous poles for studies further east in Marie Byrd Land. Combining middle Cretaceous poles determined for three other studies of the Antarctic Peninsula, Thurston Island, and the Ruppert-Hobbs coasts with ours gives a Pacific West Antarctic pole at 215.2° E, 73.5° S (A95 4.0°, KAPPA 528.9). This pole is discordant by 5° to 10° from synthetic mid-Cretaceous East Antarctic reference poles, but the degree of discordance is very sensitive to the choice of the specific reference pole. The lack of native East Antarctic reference poles leaves this analysis inconclusive. Accepting 10° of discordance, we favor an interpretation where Pacific West Antarctic crustal domains or microplates have rotated clockwise 40° to 90° and translated a few degrees away from East Antarctica during Late Cretaceous time. An electronic supplement of this material may be obtained on a diskette or Anonymous FFP from KOSMOS.AGU.ORG. (LOGIN to AGU's FTP account using ANONYMOUS as the user name and GUEST as the password. Go to the right directory by typing CD APEND. Type LS to see what files are available. Type GET and the name of the file to get it. Finally, type EXIT to leave the system.) (Paper 95TC02524, Paleomagnetic study of the northern Ford Ranges, western Marie Byrd Land, West Antarctica: Motion between West and East Antarctica, Bruce Luyendyk, Stan Cisowski, Christine Smith, Steve Richard, and David Kimbrough). Diskette may be ordered from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, DC 20009; $15.00. Payment must accompany order.

Evidence of ghost suppression in gluon mass scale dynamics

NASA Astrophysics Data System (ADS)

Aguilar, A. C.; Binosi, D.; Figueiredo, C. T.; Papavassiliou, J.

2018-03-01

In this work we study the impact that the ghost sector of pure Yang-Mills theories may have on the generation of a dynamical gauge boson mass scale, which hinges on the appearance of massless poles in the fundamental vertices of the theory, and the subsequent realization of the well-known Schwinger mechanism. The process responsible for the formation of such structures is itself dynamical in nature, and is governed by a set of Bethe-Salpeter type of integral equations. While in previous studies the presence of massless poles was assumed to be exclusively associated with the background-gauge three-gluon vertex, in the present analysis we allow them to appear also in the corresponding ghost-gluon vertex. The full analysis of the resulting Bethe-Salpeter system reveals that the contribution of the poles associated with the ghost-gluon vertex are particularly suppressed, their sole discernible effect being a slight modification in the running of the gluon mass scale, for momenta larger than a few GeV. In addition, we examine the behavior of the (background-gauge) ghost-gluon vertex in the limit of vanishing ghost momentum, and derive the corresponding version of Taylor's theorem. These considerations, together with a suitable Ansatz, permit us the full reconstruction of the pole sector of the two vertices involved.

Membrane curvature and the Tol-Pal complex determine polar localization of the chemoreceptor Tar in E. coli.

PubMed

Saaki, Terrens N V; Strahl, Henrik; Hamoen, Leendert W

2018-02-20

Chemoreceptors are localized at the cell poles of Escherichia coli and other rod-shaped bacteria. Over the years different mechanisms have been put forward to explain this polar localization; from stochastic clustering, membrane curvature driven localization, interactions with the Tol-Pal complex, to nucleoid exclusion. To evaluate these mechanisms, we monitored the cellular localization of the aspartate chemoreceptor Tar in different deletion mutants. We did not find any indication for either stochastic cluster formation or nucleoid exclusion. However, the presence of a functional Tol-Pal complex appeared to be essential to retain Tar at cell poles. Interestingly, Tar still accumulated at midcell in tol and in pal deletion mutants. In these mutants, the protein appears to gather at the base of division septa, a region characterised by strong membrane curvature. Chemoreceptors, like Tar, form trimer-of-dimers that bend the cell membrane due to a rigid tripod structure. The curvature approaches the curvature of the cell membrane generated during cell division, and localization of chemoreceptor tripods at curved membrane areas is therefore energetically favourable as it lowers membrane tension. Indeed, when we introduced mutations in Tar that abolish the rigid tripod structure, the protein was no longer able to accumulate at midcell or cell poles. These findings favour a model where chemoreceptor localization in E. coli is driven by strong membrane curvature and association with the Tol-Pal complex. Importance Bacteria have exquisite mechanisms to sense and to adapt to the environment they live in. One such mechanism involves the chemotaxis signal transduction pathway, in which chemoreceptors specifically bind certain attracting or repelling molecules and transduce the signals to the cell. In different rod-shaped bacteria, these chemoreceptors localize specifically to cell poles. Here, we examined the polar localization of the aspartate chemoreceptor Tar in E. coli , and found that membrane curvature at cell division sites and the Tol-Pal protein complex, localize Tar at cell division sites, the future cell poles. This study shows how membrane curvature can guide localization of proteins in a cell. Copyright © 2018 American Society for Microbiology.

A new Late Cretaceous paleomagnetic pole from the Adel Mountains, west central Montana

NASA Astrophysics Data System (ADS)

Gunderson, Jay A.; Sheriff, Steven D.

1991-01-01

North America's apparent polar wander path has been poorly defined between the mid-Cretaceous and Paleocene reference pole positions. Existing data allowed 13° of apparent polar motion over about 22 m.y. (87-65 Ma) roughly coinciding with the beginning of Laramide deformation (˜80 Ma). We report on a paleomagnetic study of the Adel Mountain Volcanic rocks to refine the North American apparent polar wander path for this interval. The shonkinite rocks of the Adel Mountain Volcanic field are on the eastern edge of the Cretaceous-Paleocene fold and thrust belt; some of these structures disturb the western edge of the volcanic pile. We obtained two new K-Ar dates from the Adel rocks. One date, on biotite ( from a shonkinite dike that crosscuts most of the volcanic rocks, is 71.2±2.7 Ma. The other, a whole rock date from a flow deep in the volcanic pile, is 81.1±3.5 Ma. We collected six to nine paleomagnetic samples from each of 34 sites in roadcuts and natural outcrops of flows, dikes, and laccoliths. Positive fold and conglomerate tests, along with alternating field and thermal demagnetization, indicate that our characteristic remanent directions are primary magnetizations acquired before Late Cretaceous to Paleocene thrust belt deformation. Averaging the virtual geomagnetic poles from 26 reliable sites, all of normal polarity, yields a paleopole at 82.2°N, 209.9°E (α95 = 6.80°, k = 18.38). This pole is concordant with the Paleocene reference pole (82.0°N, 170.2°E, α95 = 3.5°, k = 18.6 (Diehl et al., 1983)) and is 11.6° from the Globerman and Irving (1988) mid-Cretaceous pole at 71°N, 196°E. The youngest information in the Cretaceous stillstand pole is from the Niobrara Formation (Shive and Frerichs, 1974) at about 85-89 Ma. If we take the average age of the Adel Mountain Volcanics to be 76 Ma, then ˜12° of apparent polar motion occurred between 87 Ma and 76 Ma. Thus, rapid apparent polar motion correlates well with the onset of Laramide deformation.

An improved study of the kappa resonance and the non-exotic s wave πK scatterings up to √{s}=2.1 GeV of LASS data

NASA Astrophysics Data System (ADS)

Zhou, Z. Y.; Zheng, H. Q.

2006-09-01

We point out that the dispersion relation for the left-hand cut integral presented in one of our previous paper [H.Q. Zheng, et al., Nucl. Phys. A 733 (2004) 235] is actually free of subtraction constant, even for unequal mass elastic scatterings. A new fit to the LASS data [D. Aston, et al., LASS Collaboration, Nucl. Phys. B 296 (1988) 493] is performed and firm evidence for the existence of κ pole is found. The correct use of analyticity also put strong constraints on threshold parameters—which are found to be in good agreement with those obtained from chiral theories. We also determined the pole parameters of K0∗(1430) on the second sheet, and reconfirm the existence of K0∗(1950) on the third sheet. We stress that the LASS data do not require them to have the twin pole structure of a typical Breit-Wigner resonance.

Geologic Mapping of the Lunar South Pole Quadrangle (LQ-30)

NASA Technical Reports Server (NTRS)

Mest, S. C.; Berman, D. C.; Petro, N. E.

2010-01-01

In this study we use recent image, spectral and topographic data to map the geology of the lunar South Pole quadrangle (LQ-30) at 1:2.5M scale [1-7]. The overall objective of this research is to constrain the geologic evolution of LQ-30 (60 -90 S, 0 - 180 ) with specific emphasis on evaluation of a) the regional effects of impact basin formation, and b) the spatial distribution of ejecta, in particular resulting from formation of the South Pole-Aitken (SPA) basin and other large basins. Key scientific objectives include: 1) Determining the geologic history of LQ-30 and examining the spatial and temporal variability of geologic processes within the map area. 2) Constraining the distribution of impact-generated materials, and determining the timing and effects of major basin-forming impacts on crustal structure and stratigraphy in the map area. And 3) assessing the distribution of potential resources (e.g., H, Fe, Th) and their relationships with surface materials.

Origins of chemoreceptor curvature sorting in Escherichia coli

PubMed Central

Draper, Will; Liphardt, Jan

2017-01-01

Bacterial chemoreceptors organize into large clusters at the cell poles. Despite a wealth of structural and biochemical information on the system's components, it is not clear how chemoreceptor clusters are reliably targeted to the cell pole. Here, we quantify the curvature-dependent localization of chemoreceptors in live cells by artificially deforming growing cells of Escherichia coli in curved agar microchambers, and find that chemoreceptor cluster localization is highly sensitive to membrane curvature. Through analysis of multiple mutants, we conclude that curvature sensitivity is intrinsic to chemoreceptor trimers-of-dimers, and results from conformational entropy within the trimer-of-dimers geometry. We use the principles of the conformational entropy model to engineer curvature sensitivity into a series of multi-component synthetic protein complexes. When expressed in E. coli, the synthetic complexes form large polar clusters, and a complex with inverted geometry avoids the cell poles. This demonstrates the successful rational design of both polar and anti-polar clustering, and provides a synthetic platform on which to build new systems. PMID:28322223

Rotor apparatus for high strength undiffused brushless electric machine

DOEpatents

Hsu, John S [Oak Ridge, TN

2006-01-24

A radial gap brushless electric machine (30) having a stator (31) and a rotor (32) and a main air gap (34) also has at least one stationary excitation coil (35a, 36a) separated from the rotor (32) by a secondary air gap (35e, 35f, 36e, 36f) so as to induce a secondary flux in the rotor (32) which controls a resultant flux in the main air gap (34). Permanent magnetic (PM) material (38) is disposed in spaces between the rotor pole portions (39) to inhibit the second flux from leaking from the pole portions (39) prior to reaching the main air gap (34). By selecting the direction of current in the stationary excitation coil (35a, 36a) both flux enhancement and flux weakening are provided for the main air gap (34). Improvements of a laminated rotor, an end pole structure, and an arrangement of the PM elements for providing an arrangement of the flux paths from the auxiliary field coil assemblies are also disclosed.

How much material do the radar-bright craters at the Mercurian poles contain?

NASA Astrophysics Data System (ADS)

Vilas, Faith; Cobian, Paul S.; Barlow, Nadine G.; Lederer, Susan M.

2005-12-01

The depth-to-diameter (d/D) ratios were determined for 12 craters located near the Mercurian north pole that were identified by Harmon et al. (2001, Icarus 149) as having strong depolarized radar echos. We find that the mean d/D value of these radar-bright craters is {2}/{3} the mean d/D value of the general population of non-radar-bright craters in the surrounding north polar region. Previous studies, however, show no difference between d/D values of Mercurian polar and equatorial crater populations, suggesting that no terrain softening which could modify crater structure exists at the Mercurian poles (Barlow et al., 1999, 194, Icarus 141). Thus, the change in d/D is governed by a change in crater depth, probably due to deposition of material inside the crater. The volume of infilling material, including volatiles, in the radar-bright craters is significantly greater than predicted by proposed mechanisms for the emplacement of either water ice or sulfur.

Simulation-Based Evaluation of Light Posts and Street Signs as 3-D Geolocation Targets in SAR Images

NASA Astrophysics Data System (ADS)

Auer, S.; Balss, U.

2017-05-01

The assignment of phase center positions (in 2D or 3D) derived from SAR data to physical object is challenging for many man-made structures such as buildings or bridges. In contrast, light poles and traffic signs are promising targets for tasks based on 3-D geolocation as they often show a prominent and spatially isolated appearance. For a detailed understanding of the nature of both targets, this paper presents results of a dedicated simulation case study, which is based on ray tracing methods (simulator RaySAR). For the first time, the appearance of the targets is analyzed in 2D (image plane) and 3D space (world coordinates of scene model) and reflecting surfaces are identified for related dominant image pixels. The case studies confirms the crucial impact of spatial resolution in the context of light poles and traffic signs and the appropriateness of light poles as target for 3-D geolocation in case of horizontal ground surfaces beneath.

Optimal Frequency-Domain System Realization with Weighting

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Maghami, Peiman G.

1999-01-01

Several approaches are presented to identify an experimental system model directly from frequency response data. The formulation uses a matrix-fraction description as the model structure. Frequency weighting such as exponential weighting is introduced to solve a weighted least-squares problem to obtain the coefficient matrices for the matrix-fraction description. A multi-variable state-space model can then be formed using the coefficient matrices of the matrix-fraction description. Three different approaches are introduced to fine-tune the model using nonlinear programming methods to minimize the desired cost function. The first method uses an eigenvalue assignment technique to reassign a subset of system poles to improve the identified model. The second method deals with the model in the real Schur or modal form, reassigns a subset of system poles, and adjusts the columns (rows) of the input (output) influence matrix using a nonlinear optimizer. The third method also optimizes a subset of poles, but the input and output influence matrices are refined at every optimization step through least-squares procedures.

Orbiter escape pole

NASA Technical Reports Server (NTRS)

Goodrich, Winston D. (Inventor); Wesselski, Clarence J. (Inventor); Pelischek, Timothy E. (Inventor); Becker, Bruce H. (Inventor); Kahn, Jon B. (Inventor); Grimaldi, Margaret E. (Inventor); McManamen, John P. (Inventor); Castro, Edgar O. (Inventor)

1989-01-01

A Shuttle type of aircraft (10) with an escape hatch (12) has an arcuately shaped pole housing (16) attachable to an interior wall and ceiling with its open end adjacent to the escape hatch. The pole housing 16 contains a telescopically arranged and arcuately shaped primary pole member (22) and extension pole member (23) which are guided by roller assemblies (30,35). The extension pole member (23) is slidable and extendable relative to the primary pole member (22). For actuation, a spring actuated system includes a spring (52) in the pole housing. A locking member (90) engages both pole members (22,23) through notch portions (85,86) in the pole members. The locking member selectively releases the extension pole member (23) and the primary pole member (22). An internal one-way clutch or anti-return mechanism prevents retraction of the extension pole member from an extended position. Shock absorbers (54)(150,152) are for absoring the energy of the springs. A manual backup deployment system is provided which includes a canted ring (104) biased by a spring member (108). A lever member (100) with a slot and pin connection (102) permits the mechanical manipulation of the canted ring to move the primary pole member. The ring (104) also prevents retraction of the main pole. The crew escape mechanism includes a magazine (60) and a number of lanyards (62), each lanyard being mounted by a roller loop (68) over the primary pole member (22). The strap on the roller loop has stitching for controlled release, a protection sheath (74) to prevent tangling and a hook member (69) for attachment to a crew harness.

Metal explosion chambers: designing, manufacturing, application

NASA Astrophysics Data System (ADS)

Stoyanovskii, O. I.; Zlobin, B. S.; Shtertser, A. A.; Meshcheryakov, Y. P.

2017-10-01

Designing of explosion chambers is based on research investigations of the chamber body stress-strain state, which is determined by numerical computation and experimentally by the strain gage technique. Studies show that chamber bottoms are the most loaded elements, and maximal stresses arise in chamber poles. Increasing the shell thickness around poles by welding-in an insert is a simple and saving way to solve this problem. There are structural solutions, enabling reliable hermetic closure and preventing leakage of detonation products from the chamber. Explosion chambers are employed in scientific research and in different industrial applications: explosive welding and hardening, synthesis of new materials, disposal of expired ammunition, and etc.

Ferroelectric to paraelectric phase transition mechanism in poled PVDF-TrFE copolymer films

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

Pramanick, A.; T. Misture, Scott; Osti, Naresh C.

2017-11-01

Direct experimental insights into the structural and dynamical mechanisms for ferroelectric β to paraelectric α phase transition in a poled PVDF-TrFE copolymer is obtained from in situ x-ray diffraction and quasielastic neutron scattering measurements at high temperatures. It is observed that the β-to-α phase transition proceeds through two energetically distinct processes, which are identified here as the nucleation and growth of an intermediate γ phase with random skew linkages followed by a γ-to-α transition. The two energetically distinct microscopic processes can explain the stages of evolution for β-to-α phase transition observed from heat flow measurements.

On the extraction of P 11 resonances from πN data

DOE PAGES

Hiroyuki Kamano; Nakamura, Satoshi X.; Lee, Tsung -Shung; ...

2010-06-22

With the accuracy of the available P 11 amplitudes of πΔ scattering, we show that two resonance poles near the pi Delta threshold, obtained in several analyses, are stable against large variations of parameters within a dynamical coupled-channels analysis. The number of poles in the 1.5 GeV < W < 2 GeV region could be more than one, depending on how the structure of the single-energy solution of SAID is fitted. Lastly, our results indicate the need of more accurate πN scattering data in the W > 1.6 GeV region for high precision resonance extractions.

47 CFR 1.1404 - Complaint.

Code of Federal Regulations, 2014 CFR

2014-10-01

... default rate of return; (xi) The average amount of usable space per pole for those poles used for pole... unusable space per pole for those poles used for pole attachments (a 24 foot presumption may be used in...) The number of ducts in the conduit subject to the complaint; (vi) The number of inner-ducts in the...

47 CFR 1.1404 - Complaint.

Code of Federal Regulations, 2011 CFR

2011-10-01

... default rate of return; (xi) The average amount of usable space per pole for those poles used for pole... unusable space per pole for those poles used for pole attachments (a 24 foot presumption may be used in...) The number of ducts in the conduit subject to the complaint; (vi) The number of inner-ducts in the...

47 CFR 1.1404 - Complaint.

Code of Federal Regulations, 2013 CFR

2013-10-01

... default rate of return; (xi) The average amount of usable space per pole for those poles used for pole... unusable space per pole for those poles used for pole attachments (a 24 foot presumption may be used in...) The number of ducts in the conduit subject to the complaint; (vi) The number of inner-ducts in the...

Texture and anisotropy in ferroelectric lead metaniobate

NASA Astrophysics Data System (ADS)

Iverson, Benjamin John

Ferroelectric lead metaniobate, PbNb2O6, is a piezoelectric ceramic typically used because of its elevated Curie temperature and anisotropic properties. However, the piezoelectric constant, d33, is relatively low in randomly oriented ceramics when compared to other ferroelectrics. Crystallographic texturing is often employed to increase the piezoelectric constant because the spontaneous polarization axes of grains are better aligned. In this research, crystallographic textures induced through tape casting are distinguished from textures induced through electrical poling. Texture is described using multiple quantitative approaches utilizing X-ray and neutron time-of-flight diffraction. Tape casting lead metaniobate with an inclusion of acicular template particles induces an orthotropic texture distribution. Templated grain growth from seed particles oriented during casting results in anisotropic grain structures. The degree of preferred orientation is directly linked to the shear behavior of the tape cast slurry. Increases in template concentration, slurry viscosity, and casting velocity lead to larger textures by inducing more particle orientation in the tape casting plane. The maximum 010 texture distributions were two and a half multiples of a random distribution. Ferroelectric texture was induced by electrical poling. Electric poling increases the volume of material oriented with the spontaneous polarization direction in the material. Samples with an initial paraelectric texture exhibit a greater change in the domain volume fraction during electrical poling than randomly oriented ceramics. In tape cast samples, the resulting piezoelectric response is proportional to the 010 texture present prior to poling. This results in property anisotropy dependent on initial texture. Piezoelectric properties measured on the most textured ceramics were similar to those obtained with a commercial standard.

47 CFR 36.151 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... communications plant in service: Poles and antenna supporting structures, aerial cable, underground cable, buried... 47 Telecommunication 2 2011-10-01 2011-10-01 false General. 36.151 Section 36.151 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES JURISDICTIONAL SEPARATIONS...

Fatigue Testing of Ring-Stiffened Traffic Signal Structures.

DOT National Transportation Integrated Search

2010-10-09

Based on in-service inspection of poles with traditional designs, the inventory of Wyoming Department of Transportation ?WYDOT? exhibited approximately a one-third cracking rate. A ring-stiffened connection is presently used. Sixteen fatigue tests we...

What is the function of centrioles?

PubMed

Marshall, Wallace F

2007-03-01

The function of centrioles has been controversial and remains incompletely resolved. This is because centrioles, in and of themselves, do not directly perform any physiological activity. Instead, their role is only to act as a jig or breadboard onto which other functional structures can be built. Centrioles are primarily involved in forming two structures-centrosomes and cilia. Centrioles bias the position of spindle pole formation, but because spindle poles can self-organize, the function of the centriole in mitosis is not obligatory. Consequently, lack of centrioles does not generally prevent mitosis, although recent experiments suggest acentriolar spindles have reduced fidelity of chromosome segregation. In contrast, centrioles are absolutely required for the assembly of cilia, including primary cilia that act as cellular antennae. Consistent with this requirement, it is now becoming clear that many ciliary diseases, including nephronophthisis, Bardet-Biedl syndrome, Meckel Syndrome, and Oral-Facial-Digital syndrome, are caused by defects in centriole-associated proteins.

New frontiers: discovering cilia-independent functions of cilia proteins.

PubMed

Vertii, Anastassiia; Bright, Alison; Delaval, Benedicte; Hehnly, Heidi; Doxsey, Stephen

2015-10-01

In most vertebrates, mitotic spindles and primary cilia arise from a common origin, the centrosome. In non-cycling cells, the centrosome is the template for primary cilia assembly and, thus, is crucial for their associated sensory and signaling functions. During mitosis, the duplicated centrosomes mature into spindle poles, which orchestrate mitotic spindle assembly, chromosome segregation, and orientation of the cell division axis. Intriguingly, both cilia and spindle poles are centrosome-based, functionally distinct structures that require the action of microtubule-mediated, motor-driven transport for their assembly. Cilia proteins have been found at non-cilia sites, where they have distinct functions, illustrating a diverse and growing list of cellular processes and structures that utilize cilia proteins for crucial functions. In this review, we discuss cilia-independent functions of cilia proteins and re-evaluate their potential contributions to "cilia" disorders. © 2015 The Authors.

Structural fatigue test results for large wind turbine blade sections

NASA Technical Reports Server (NTRS)

Faddoul, J. R.; Sullivan, T. L.

1982-01-01

In order to provide quantitative information on the operating life capabilities of wind turbine rotor blade concepts for root-end load transfer, a series of cantilever beam fatigue tests was conducted. Fatigue tests were conducted on a laminated wood blade with bonded steel studs, a low cost steel spar (utility pole) with a welded flange, a utility pole with additional root-end thickness provided by a swaged collar, fiberglass spars with both bonded and nonbonded fittings, and, finally, an aluminum blade with a bolted steel fitting (Lockheed Mod-0 blade). Photographs, data, and conclusions for each of these tests are presented. In addition, the aluminum blade test results are compared to field failure information; these results provide evidence that the cantilever beam type of fatigue test is a satisfactory method for obtaining qualitative data on blade life expectancy and for identifying structurally underdesigned areas (hot spots).

Musical Creativity “Revealed” in Brain Structure: Interplay between Motor, Default Mode, and Limbic Networks

PubMed Central

Bashwiner, David M.; Wertz, Christopher J.; Flores, Ranee A.; Jung, Rex E.

2016-01-01

Creative behaviors are among the most complex that humans engage in, involving not only highly intricate, domain-specific knowledge and skill, but also domain-general processing styles and the affective drive to create. This study presents structural imaging data indicating that musically creative people (as indicated by self-report) have greater cortical surface area or volume in a) regions associated with domain-specific higher-cognitive motor activity and sound processing (dorsal premotor cortex, supplementary and pre-supplementary motor areas, and planum temporale), b) domain-general creative-ideation regions associated with the default mode network (dorsomedial prefrontal cortex, middle temporal gyrus, and temporal pole), and c) emotion-related regions (orbitofrontal cortex, temporal pole, and amygdala). These findings suggest that domain-specific musical expertise, default-mode cognitive processing style, and intensity of emotional experience might all coordinate to motivate and facilitate the drive to create music. PMID:26888383

Coronal Polarization of Pseudostreamers and the Solar Polar Field Reversal

NASA Technical Reports Server (NTRS)

Rachmeler, L. A.; Guennou, C.; Seaton, D. B.; Gibson, S. E.; Auchere, F.

2016-01-01

The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP polarization data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere, the last vestiges of the previous polar field polarity remained until March 2015. We present here the evolution of the structure and describe its identification in the Fe XII 1074nm coronal emission line, sensitive to the Hanle effect in the corona.

The Moon's North Pole

NASA Image and Video Library

2017-12-08

NASA image release September 7, 2011 The Earth's moon has been an endless source of fascination for humanity for thousands of years. When at last Apollo 11 landed on the moon's surface in 1969, the crew found a desolate, lifeless orb, but one which still fascinates scientist and non-scientist alike. This image of the moon's north polar region was taken by the Lunar Reconnaissance Orbiter Camera, or LROC. One of the primary scientific objectives of LROC is to identify regions of permanent shadow and near-permanent illumination. Since the start of the mission, LROC has acquired thousands of Wide Angle Camera images approaching the north pole. From these images, scientists produced this mosaic, which is composed of 983 images taken over a one month period during northern summer. This mosaic shows the pole when it is best illuminated, regions that are in shadow are candidates for permanent shadow. Image Credit: NASA/GSFC/Arizona State University NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Kolakoski sequence as an element to radiate giant forward and backward second harmonic signals

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

Parvini, T. S.; Tehranchi, M. M., E-mail: m-hamidi@sbu.ac.ir, E-mail: teranchi@sbu.ac.ir; Laser and Plasma Research Institute, Shahid Beheshti University, Tehran

2015-11-14

We propose a novel type of aperiodic one-dimensional photonic crystal structures which can be used for generating giant forward and backward second harmonic signals. The studied structure is formed by stacking together the air and nonlinear layers according to the Kolakoski self-generation scheme in which each nonlinear layer contains a pair of antiparallel 180° poled LiNbO{sub 3} crystal layers. For different generation stages of the structure, conversion efficiencies of forward and backward second harmonic waves have been calculated by nonlinear transfer matrix method. Numerical simulations show that conversion efficiencies in the Kolakoski-based multilayer are larger than the perfect ones formore » at least one order of magnitude. Especially for 33rd and 39th generation stages, forward second harmonic wave are 42 and 19 times larger, respectively. In this paper, we validate the strong fundamental field enhancement and localization within Kolakoski-based multilayer due to periodicity breaking which consequently leads to very strong radiation of backward and forward second harmonic signals. Following the applications of analogous aperiodic structures, we expect that Kolakosi-based multilayer can play a role in optical parametric devices such as multicolor second harmonic generators with high efficiency.« less

Coincident Above- and Below-ground Autonomous Monitoring to Quantify Co-variability in Permafrost, Soil and Vegetation Properties in Arctic Tundra: Supporting Data

DOE Data Explorer

Baptiste Dafflon; Rusen Oktem; John Peterson; Craig Ulrich; Anh Phuong Tran; Vladimir Romanovsky; Susan Hubbard

2017-05-10

The dataset contains measurements obtained through electrical resistivity tomography (ERT) to monitor soil properties, pole-mounted optical cameras to monitor vegetation dynamics, point probes to measure soil temperature, and periodic manual measurements of thaw layer thickness, snow thickness and soil dielectric permittivity.

The Sensitive Infrared Signal Detection by Sum Frequency Generation

NASA Technical Reports Server (NTRS)

Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin

2013-01-01

An up-conversion device that converts 2.05-micron light to 700 nm signal by sum frequency generation using a periodically poled lithium niobate crystal is demonstrated. The achieved 92% up-conversion efficiency paves the path to detect extremely weak 2.05-micron signal with well established silicon avalanche photodiode detector for sensitive lidar applications.

Analytical Design of Terminally Guided Missiles.

DTIC Science & Technology

1980-01-02

Equivalent Dominant Poles and Zeros Using Industrial Specifications," Trans. on Industrial Electronics and Control Instrumentation, Vol. IECI-26, No...The relaxation of the sampling period requirement and the flexibility of our new method facilitate the practical industrial implementation and...with the Guidance and Control Directorate, U.S. Army Missile Command, Redstone Arsenal, Alabama 35809. I. INTRODUCTION Most practical industrial circuits

Growth and mortality of ponderosa pine poles thinned to various densities in the Blue Mountains of Oregon.

Treesearch

P.H. Cochran; James W. Barrett

1995-01-01

Growth and mortality in a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) stand were investigated for 24 years. High mortality rates from mountain pine beetle (Dendroctonus ponderosae Hopkins) occurred on some plots where values for stand density index exceeded 140. Periodic annual increments for quadratic mean diameters...

The Process of Facilitating Knowledge Acquisition and Retention: An Inquiry into Magnetic Poles with Challenging Questions

ERIC Educational Resources Information Center

Okulu, Hasan Zühtü; Ünver, Ayse Oguz

2018-01-01

The current research is to give an example to the inquiry-based science teaching implementations for facilitating knowledge acquisition and retention in a short period of time. Thus, the aim of the research is to transfer of acquired knowledge into different situations using sequential inquiry activities, which have challenging questions for…

77 FR 66479 - Public Land Order No. 7805; Extension of Public Land Order No. 6952; WA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-05

...-year period. The extension is necessary to continue protection of the tree improvement and forest... telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 1-800- 877-8339... withdrawal was first made requires this extension to continue protection of the Peony, Pole Pick, and Frank...

Taper of wood poles

Treesearch

Billy Bohannan; Hermann Habermann; Joan E. Lengel

1974-01-01

Round wood pole use has changed without accompanying advancement in engineering design data. Previous pole design was based on the assumption that maximum stress occurred at the groundline but, with the larger poles that are now being used, maximum stress may occur along the pole length. For accurate engineering analysis the shape or taper of a pole must be known. Both...

Magnet pole tips

DOEpatents

Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

1984-04-24

An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

Magnet pole tips

DOEpatents

Thorn, C.E.; Chasman, C.; Baltz, A.J.

1981-11-19

An improved magnet more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

An accelerating high-latitude jet in Earth's core

NASA Astrophysics Data System (ADS)

Finlay, C. C.; Livermore, P. W.; Hollerbach, R.

2016-12-01

The structure of the core-generated magnetic field, and how it changes in time (its secular variation or SV), supplies an invaluable constraint on the dynamics of the outer core. At high latitude, previous studies have noted distinctive behaviour of secular change, in particular suggesting a polar vortex tied to the dynamics within the tangent cylinder region. Recent high-resolution observational models that include data from the Swarm satellites have refined the structure of observed SV, to a rapidly changing circular daisy-chain configuration centred on the north geographic pole, on or very close to the tangent cylinder itself. Motivated by theoretical considerations of the likely dynamical regime of the core, we demonstrate that this feature can be explained by a localised westwards cylindrical jet of 420 km width centred the tangent cylinder, whose amplitude appears to have increased in strength by a factor of three over the period 2000-2016 to about 40 km/yr. The current accelerating phase may be a short fragment of decadal fluctuations of the jet strength linked to both torsional wave activity and the rotation direction of the inner core.

Widely tunable eye-safe laser by a passively Q-switched photonic crystal fiber laser and an external-cavity optical parametric oscillator

NASA Astrophysics Data System (ADS)

Chang, H. L.; Zhuang, W. Z.; Huang, W. C.; Huang, J. Y.; Huang, K. F.; Chen, Y. F.

2011-09-01

We report on a widely tunable passively Q-switched photonic crystal fiber (PCF) laser with wavelength tuning range up to 80 nm. The PCF laser utilizes an AlGaInAs quantum well/barrier structure as a saturable absorber and incorporates an external-cavity optical parametric oscillator (OPO) to achieve wavelength conversion. Under a pump power of 13.1 W at 976 nm, the PCF laser generated 1029-nm radiation with maximum output energy of 750 μJ and was incident into an external-cavity OPO. The output energy and peak power of signal wave was found to be 138 μJ and 19 kW, respectively. By tuning the temperature of nonlinear crystal, periodically poled lithium niobate (PPLN), in the OPO, the signal wavelength in eye-safe regime from 1513 to 1593 nm was obtained.

A vanadium-doped ZnO nanosheets-polymer composite for flexible piezoelectric nanogenerators.

PubMed

Shin, Sung-Ho; Kwon, Yang Hyeog; Lee, Min Hyung; Jung, Joo-Yun; Seol, Jae Hun; Nah, Junghyo

2016-01-21

We report high performance flexible piezoelectric nanogenerators (PENGs) by employing vanadium (V)-doped ZnO nanosheets (NSs) and the polydimethylsiloxane (PDMS) composite structure. The V-doped ZnO NSs were synthesized to overcome the inherently low piezoelectric properties of intrinsic ZnO. Ferroelectric phase transition induced in the V-doped ZnO NSs contributed to significantly improve the performance of the PENGs after the poling process. Consequently, the PENGs exhibited high output voltage and current up to ∼32 V and ∼6.2 μA, respectively, under the applied strain, which are sufficient to directly turn on a number of light emitting diodes (LEDs). The composite approach for PENG fabrication is scalable, robust, and reproducible during periodic bending/releasing over extended cycles. The approach introduced here extends the performance limits of ZnO-based PENGs and demonstrates their potential as energy harvesting devices.

Place in History and Astrophysics as the Pole Star and the Nearest Cepheid

NASA Astrophysics Data System (ADS)

Guinan, Edward F.

2012-05-01

Over ten centuries ago years, precession moved the Earth's North Celestial Pole (NCP) near the direction of alpha Ursae Minoris - now known as Polaris. Since that time Polaris has served as an important navigation star. By 2100 (at closest approach) Polaris moves within 0.5 deg of the NCP. Because of its brightness ( 2nd mag) and fixed place in the sky, Polaris is frequently referenced in literature, folklore, and pop culture. For example, in the Arctic, Polaris is known to the Inuit (among other names) as Nuuttuittuq ("never moves"), while the Yup'ik Eskimo refer to Polaris as Agyarrlak ("major star"). But Polaris, as the nearest Classical Cepheid (and also member of a multiple star system) is astrophysically important and interesting in its own right. Primarily this is because Polaris' physical properties can be precisely determined. Its distance provides a luminosity, pulsation mode and calibration for the Leavitt Law (Period-Luminosity relation). But, Polaris has been found to be full of surprises and puzzles. Over the last century Polaris has been undergoing rapid, large changes in its pulsation period (increasing at over 4 sec/yr.) as well as in its light and radial velocity variations. Noteworthy, during the early-1990s, Polaris nearly stopped pulsating and thus almost ceased being a Cepheid! Surprisingly Polaris (and other Cepheids) recently have been discovered to have significant mass-loss, and to display X-ray and FUV-line emission variations in phase with their pulsations. In this introductory talk Polaris' place in history and in the field of astronomy will be briefly discussed along with the important role it plays in the broader understanding of Cepheid structure and evolution. This research is, in part, supported by NASA Grants HST-GO11726.01 and NNX08AX37G, which we gratefully acknowledge.

95 Minutes Over Jupiter

NASA Image and Video Library

2017-09-28

This sequence of color-enhanced images shows how quickly the viewing geometry changes for NASA's Juno spacecraft as it swoops by Jupiter. The images were obtained by JunoCam. Once every 53 days, Juno swings close to Jupiter, speeding over its clouds. In just two hours, the spacecraft travels from a perch over Jupiter's north pole through its closest approach (perijove), then passes over the south pole on its way back out. This sequence shows 11 color-enhanced images from Perijove 8 (Sept. 1, 2017) with the south pole on the left (11th image in the sequence) and the north pole on the right (first image in the sequence). The first image on the right shows a half-lit globe of Jupiter, with the north pole approximately at the upper center of the image close to the terminator -- the dividing line between night and day. As the spacecraft gets closer to Jupiter, the horizon moves in and the range of visible latitudes shrinks. The second and third images in this sequence show the north polar region rotating away from the spacecraft's field of view while the first of Jupiter's lighter-colored bands comes into view. The fourth through the eighth images display a blue-colored vortex in the mid-southern latitudes near Points of Interest "Collision of Colours," "Sharp Edge," "Caltech, by Halka," and "Structure01." The Points of Interest are locations in Jupiter's atmosphere that were identified and named by members of the general public. Additionally, a darker, dynamic band can be seen just south of the vortex. In the ninth and tenth images, the south polar region rotates into view. The final image on the left displays Jupiter's south pole in the center. From the start of this sequence of images to the end, roughly 1 hour and 35 minutes elapsed. https://photojournal.jpl.nasa.gov/catalog/PIA21967

Waveguide structures in anisotropic nonlinear crystals

NASA Astrophysics Data System (ADS)

Li, Da; Hong, Pengda; Meissner, Helmuth E.

2017-02-01

We report on the design and manufacturing parameters of waveguiding structures of anisotropic nonlinear crystals that are employed for harmonic conversions, using Adhesive-Free Bonding (AFB®). This technology enables a full range of predetermined refractive index differences that are essential for the design of single mode or low-mode propagation with high efficiency in anisotropic nonlinear crystals which in turn results in compact frequency conversion systems. Examples of nonlinear optical waveguides include periodically bonded walk-off corrected nonlinear optical waveguides and periodically poled waveguide components, such as lithium triborate (LBO), beta barium borate (β-BBO), lithium niobate (LN), potassium titanyl phosphate (KTP), zinc germanium phosphide (ZGP) and silver selenogallate (AGSE). Simulation of planar LN waveguide shows that when the electric field vector E lies in the k-c plane, the power flow is directed precisely along the propagation direction, demonstrating waveguiding effect in the planar waveguide. Employment of anisotropic nonlinear optical waveguides, for example in combination with AFB® crystalline fiber waveguides (CFW), provides access to the design of a number of novel high power and high efficiency light sources spanning the range of wavelengths from deep ultraviolet (as short as 200 nm) to mid-infrared (as long as about 18 μm). To our knowledge, the technique is the only generally applicable one because most often there are no compatible cladding crystals available to nonlinear optical cores, especially not with an engineer-able refractive index difference and large mode area.

Diagnostic Power of Macular Retinal Thickness Analysis and Structure-Function Relationship in Glaucoma Diagnosis Using SPECTRALIS OCT.

PubMed

Rolle, Teresa; Manerba, Linda; Lanzafame, Pietro; Grignolo, Federico M

2016-05-01

To evaluate the diagnostic power of the Posterior Pole Asymmetry Analysis (PPAA) from the SPECTRALIS OCT in glaucoma diagnosis and to define the correlation between the visual field sensitivity (VFS) and macular retinal thickness (MRT). 90 consecutive open-angle glaucoma patients and 23 healthy subjects were enrolled. All subjects underwent Visual Field test (Humphrey Field Analyzer, central 24-2 SITA-Standard) and SD-OCT volume scans (SPECTRALIS, Posterior Pole Asymmetry Analysis). The areas under the Receiving Operating Characteristic curve (AROC) were calculated to assess discriminating power for glaucoma, at first considering total MRT values and hemisphere MRT value and then quadrant MRT values from 16 square cells in a 8 x 8 posterior pole retinal thickness map that were averaged for a mean retinal thickness value. Structure function correlation was performed for total values, hemisphere values and for each quadrant compared to the matching central test points of the VF. The AROCs ranged from 0.70 to 0.82 (p < 0.0001), with no significant differences between each other. The highest AROC observed was in inferior nasal quadrant. The VFS showed a strong correlation only with the corresponding MRT value s for quadrant analysis: Superior Temporal (r = 0.33, p = 0.0013), Superior Nasal (r = 0.43, p < 0.0001), Inferior Temporal (r = 0.57, p < 0.0001) and Inferior Nasal (r = 0.55, p < 0.0001). the quadrant analysis showed statistically significant structure-function correlations and may provide additional data for the diagnostic performance of SPECTRALIS OCT.

Illumination effects on the ferroelectric and photovoltaic properties of Pb0.95La0.05Zr0.54Ti0.46O3 thin film based asymmetric MFM structure

NASA Astrophysics Data System (ADS)

Batra, V.; Kotru, S.

2017-12-01

We report the effects of illumination on the ferroelectric and photovoltaic properties of the Pb0.95La0.05Zr0.54Ti0.46O3 (PLZT) thin film based asymmetric metal/ferroelectric/metal capacitor structure, using Au as a top electrode and Pt as a bottom electrode. Conductive-AFM (atomic force microscopy) measurements demonstrate the evolution of charge carriers in PLZT films on illumination. The capacitance-voltage, the polarization-electric field, and the leakage current-voltage characteristics of the asymmetric Au/PLZT/Pt capacitor are discussed under dark and illuminated conditions. The light generates charge carriers in the film, which increase the coercive field and net remnant polarization and decrease the capacitance. The leakage current of the capacitor increases by an order of magnitude upon illumination. The leakage current data analyzed to study the conduction mechanism shows that the capacitor structure follows the Schottky emission "1/4" law. The illuminated current density-voltage curve of the capacitor shows non-zero photovoltaic parameters. An open circuit voltage (Voc) of -0.19 V and a short circuit current density (Jsc) of 1.48 μA/cm2 were obtained in an unpoled film. However, after positive poling, the illuminated curve shifts towards a higher voltage value resulting in a Voc of -0.93 V. After negative poling, the curve shows no change in the Voc value. For both poling directions, the Jsc values decrease. The photocurrent in the capacitor shows a linear variation with the incident illumination intensity.

Fabrication and Characterization of Linear and Nonlinear Photonic Devices in Fused Silica by Femtosecond Laser Writing

NASA Astrophysics Data System (ADS)

Ng, Jason Clement

Femtosecond laser processing is a flexible, three-dimensional (3D) fabrication technique used to make integrated low-loss photonic devices in fused silica. My work expanded the suite of available optical devices through the design and optimization of linear optical components such as low-loss (< 0.5 dB) curved waveguides, directional couplers (DCs), and Mach-Zehnder interferometers (MZIs). The robustness and consistency of this maturing fabrication process was also reinforced through the scalable design and integration of a more complex, multi-component flat-top interleaver over a wide >70-nm spectral window. My work further complemented femtosecond laser processing with the development of nonlinear device capabilities. While thermal poling is a well known process, significant challenges had restricted the development of nonlinear devices in fused silica. The laser writing process would erase the induced nonlinearity (erasing) while a written waveguide core acted as a barrier to the thermal poling process (blocking). Using second harmonic (SH) microscopy, the effectiveness of thermal poling on laser-written waveguides was systematically analyzed leading to the technique of "double poling", which effectively overcomes the two challenges of erasing and blocking. In this new process the substrate is poled before and after waveguide writing to restore the induced nonlinearity within the vicinity of the waveguide to enable effective poling for inducing a second-order nonlinearity (SON) in fused silica. A new flexible, femtosecond laser based erasure process was also developed to enable quasi-phase matching and to form arbitrarily chirped gratings. Following this result, second harmonic generation (SHG) in a quasiphase-matched (QPM) femtosecond laser written waveguide device was demonstrated. SHG in a chirped QPM structure was also demonstrated to illustrate the flexibility of the femtosecond laser writing technique. These are the first demonstration of frequency doubling in an all-femtosecond-laser-written structure. A maximum SHG conversion efficiency of 1.3 +/- 0.1x10 -11/W-cm-2 was achieved for the fundamental wavelength of 1552.8 nm with a phase-matching bandwidth of 4.4 nm for a 10.0-mm-long waveguide. For a shorter sample, an effective SON of chi(2) = 0:020 +/- 0:002 pm/V was measured. The results collectively demonstrate the versatility of femtosecond laser additive and subtractive fabrication and opens up the development of integrated nonlinear applications and photonic devices for future lab-on-a-chip and lab-in-a-fiber devices.

Paleomagnetic poles and polarity zonation from the middle proterozoic belt supergroup, montana and Idaho

NASA Astrophysics Data System (ADS)

Elston, Donald P.; Bressler, Stephen L.

1980-01-01

Twelve paleomagnetic poles and a preliminary polarity zonation are reported from geologically mapped, stratigraphically controlled sections of the middle Proterozoic Belt Supergroup in western Montana and northern Idaho. Although gaps exist in the stratigraphic coverage, the lower Belt, Ravalli Group, and middle Belt carbonate appear to be largely if not entirely of normal polarity. A switch to reversed polarity takes place near the base of the overlying Missoula Group (base of Snowslip Fomration), and two comparatively narrow intervals of mixed polarity containing at least 18 reversals are found in the lower and middle Snowslip. Seven reversals, mostly widely spaced in stratigraphic position, have been found in overlying strata of the Missoula Group. Poles from strata of the Ravalli Group through Missoula Group are well defined and tightly clustered. They plot in the south-central Pacific Ocean and display only a small (~20°) southeast to northwest shift in pole path. Poles from Belt strata in the eastern basin plot sytematically east of poles from the more westerly collection sites. A counterclockwise shift in declination of 7°-10° is seen in strata from the easterly sites, which has given rise to a curving pole path that closely parallels the path for the westerly sites. This easterly path appears explainable as a consequence of a counterclokwise structural rotation of eastern Belt strata relative to western and central Belt strata produced during west ot east thrust faulting of late Mesozoic and early Cenozoic age. An additional counterclockwise rotation of the same magnitude exists between the northern and southern parts of the Montana fisturbed belt of the eastern Belt basin. Moreover, anomalously steep inclinations, not yet explained, have been reported from some of the strata sampled at the north end of the disturbed belt. The steep inclinations result in poles that plot distinctly east of poles reported from this study. The Belt pole path lies in a part of the North American apparent polar wander path that has been assigned an age of about 1500-1200 m.y. This is in broad agreement with isotopic ages reported for strata of the lower Belt to the middle Ravalli Group. The Belt path trends toward, and its northwest end overlaps, the beginning of the pole path for the Grand Canyon Supergroup, which formed in the interval from <~1300 to ~830 m.y. ago. Because polarity zonations differ between strata of the upper Belt and lower Grand Canyon Supergroups. Belt strata would appear, on paleomagnetic grounds, to be largely or entirely older than strata of the Grand Canyon Supergroup. However, isotopic ages for the Missoula Group (1100 m.y. and younger) presently require an alternative interpretation, i.e., that the Belt terrance did not participate in inferred plate motion which gave rise to a large north-trending loop in the inverval ~1200 to ~1100 m.y. ago and to later motion seen in the Grand Canyon path. Additional dating is needed for the Purcell Lava of the Missoula Group to support or modify the 1100 m.y. age determined by the K-Ar method.

Self Assembly and Pyroelectric Poling for Organics

DTIC Science & Technology

2015-07-06

ozone or nitrogen oxides) and energetic species from corona discharge . These problems can strongly inhibit the efficient poling and large-scale...poling techniques. Although contact and corona poling protocols are quite well established for decades, there do exist some challenging problems. In...contact poling, severe charge injection from metal electrodes often results in large current that causes dielectric breakdown of films. Corona poling

Polymerase ε (POLE) ultra-mutation in uterine tumors correlates with T lymphocyte infiltration and increased resistance to platinum-based chemotherapy in vitro

PubMed Central

Bellone, Stefania; Eliana, Bignotti; Lonardi, Silvia; Ferrari, Francesca; Centritto, Floriana; Masserdotti, Alice; Pettinella, Francesca; Black, Jonathan; Menderes, Gulden; Altwerger, Gary; Hui, Pei; Lopez, Salvatore; de Haydu, Christopher; Bonazzoli, Elena; Predolini, Federica; Zammataro, Luca; Cocco, Emiliano; Ferrari, Federico; Ravaggi, Antonella; Romani, Chiara; Facchettie, Fabio; Sartori, Enrico; Odicino, Franco E.; Silasi, Dan-Arin; Litkouhi, Babak; Ratner, Elena; Azodi, Masoud; Schwartz, Peter E.; Santin, Alessandro D.

2016-01-01

Objective Up to 12 % of all endometrial-carcinomas (EC) harbor DNA-polymerase-ε-(POLE) mutations. It is currently unknown whether the favorable prognosis of POLE-mutated EC is derived from their low metastatic capability, extraordinary number of somatic mutations thus imparting immunogenicity, or a high sensitivity to chemotherapy. Methods Polymerase-chain-reaction-amplification and Sanger-sequencing were used to test for POLE exonuclease-domain-mutations (exons 9–14) 131 EC. Infiltration of CD4+ and CD8+ T-lymphocytes (TIL) and PD-1-expression in POLE-mutated vs POLE wild-type EC was studied by immunohistochemistry (IHC) and the correlations between survival and molecular features were investigated. Finally, primary POLE-mutated and POLE-wild-type EC cell lines were established and compared in-vitro for their sensitivity to chemotherapy. Results Eleven POLE-mutated EC (8.5%) were identified. POLE-mutated tumors were associated with improved progression-free-survival (P<0.05) and displayed increased numbers of CD4+ (44.5 vs 21.8; P = .001) and CD8+ (32.8 vs 13.5; P < .001) TILs when compared to wild-type POLE EC. PD-1 receptor was overexpressed in TILs from POLE-mutated vs wild-type-tumors (81% vs 28%; P < .001). Primary POLE tumor cell lines were significantly more resistant to platinum-chemotherapy in-vitro when compared to POLE-wild-type tumors (P < 0.004). Conclusions POLE ultra-mutated EC are heavily infiltrated with CD4+/CD8+ TIL, overexpress PD-1 immune-check-point (i.e., features consistent with chronic antigen-exposure), and have a better prognosis when compared to other molecular subtypes of EC patients. POLE-mutated tumor-cell lines are resistant to platinum-chemotherapy in-vitro suggesting that the better prognosis of POLE-patients is not secondary to a higher sensitivity to chemotherapy but likely linked to enhanced immunogenicity. PMID:27894751

Production and marketing of wood piling and poles in the Northeast

Treesearch

Myron D. Ostrander

1953-01-01

Since the earliest colonial settlements along the northeastern seaboard, wood piling has been used for wharves and piers and other waterfront structures. As waterside industries and waterborne commerce grew, the demand for wood piling grew.

Seasonal and interannual variations of atmospheric CO2 and climate

NASA Astrophysics Data System (ADS)

Dettinger, Michael D.; Ghil, Michael

1998-02-01

Interannual variations of atmospheric CO2 concentrations at Mauna Loa are almost masked by the seasonal cycle and a strong trend; at the South Pole, the seasonal cycle is small and is almost lost in the trend and interannual variations. Singular-spectrum analysis (SSA) is used here to isolate and reconstruct interannual signals at both sites and to visualize recent decadal changes in the amplitude and phase of the seasonal cycle. Analysis of the Mauna Loa CO2 series illustrates a hastening of the CO2 seasonal cycle, a close temporal relation between Northern Hemisphere (NH) mean temperature trends and the amplitude of the seasonal CO2 cycle, and tentative ties between the latter and seasonality changes in temperature over the NH continents. Variations of the seasonal CO2 cycle at the South Pole differ from those at Mauna Loa: it is phase changes of the seasonal cycle at the South Pole, rather than amplitude changes, that parallel hemispheric and global temperature trends. The seasonal CO2 cycles exhibit earlier occurrences of the seasons by 7days at Mauna Loa and 18days at the South Pole. Interannual CO2 variations are shared at the two locations, appear to respond to tropical processes, and can be decomposed mostly into two periodicities, around (3years)1 and (4years)1, respectively. Joint SSA analyses of CO2 concentrations and tropical climate indices isolate a shared mode with a quasi-triennial (QT) period in which the CO2 and sea-surface temperature (SST) participation are in phase opposition. The other shared mode has a quasi-quadrennial (QQ) period and CO2 variations are in phase with the corresponding tropical SST variations throughout the tropics. Together these interannual modes exhibit a mean lag between tropical SSTs and CO2 variations of about 6 8months, with SST leading. Analysis of the QT and QQ signals in global gridded SSTs, joint SSA of CO2 and δ13C isotopic ratios, and SSA of CO2 and NH-land temperatures indicate that the QT variations in CO2 mostly reflect upwelling variations in the eastern tropical Pacific. QQ variations are dominated by the CO2 signature of terrestrial-ecosystem response to global QQ climate variations. Climate variations associated with these two interannual components of tropical variability have very different effects on global climate and, especially, on terrestrial ecosystems and the carbon cycle.

Decay resistance of out-of-service utility poles as related to the distribution of residual creosote content

Treesearch

Han Roliadi; Chung Y. Hse; Elvin T. Choong; Todd F. Shupe

2000-01-01

Decay resistance of out-of-service poles was investigated to evaluate their effectiveness against biodegradation for possible recycling of these poles for composite products. Decay resistance was related to creosote content and creosote distribution in poles with service durations of 5 and 25 years and also freshly treated poles. Weathering of the poles had caused...

Real-Time Teleguidance of a Non-Surgeon Crew Medical Officer Performing Orthopedic Surgery at the Amundsen-Scott South Pole Station During Winter-Over

NASA Technical Reports Server (NTRS)

Otto, Christian

2010-01-01

The Amundsen-Scott South Pole Research station located at the geographic South Pole, is the most isolated, permanently inhabited human outpost on Earth. Medical care is provided to station personnel by a non-surgeon crew medical officer (CMO). During the winter-over period from February to October, the station is isolated, with no incoming or outgoing flights due to severe weather conditions. In late June, four months after the station had closed for the austral winter, a 31 year old meteorologist suffered a complete rupture of his patellar tendon while sliding done an embankment. An evacuation was deemed to be too risky to aircrews due to the extreme cold and darkness. A panel of physicians from Massachusetts General Hospital, Johns Hopkins University and the University of Texas Medical Branch were able to assess the patient remotely via telemedicine and agreed that surgery was the only means to restore mobility and prevent long term disability. The lack of a surgical facility and a trained surgical team were overcome by conversion of the clinic treatment area, and intensive preparation of medical laypersons as surgical assistants. The non-surgeon CMO and CMO assistant at South Pole, were guided through the administration of spinal anesthetic, and the two-hour operative repair by medical consultants at Massachusetts General Hospital. Real-time video of the operative field, directions from the remote consultants and audio communication were provided by videoconferencing equipment, operative cameras, and high bandwidth satellite communications. In real-time, opening incision/exposure, tendon relocation, hemostatsis, and operative closure by the CMO was closely monitored and guided and by the remote consultants. The patient s subsequent physical rehabilitation over the ensuing months of isolation was also monitored remotely via telemedicine. This was the first time in South Pole s history that remote teleguidance had been used for surgery and represents a model for real-time guidance of CMO s working at remote duty stations.

Is Ice-Rafted Sediment in a North Pole Marine Record Evidence for Perennial Sea-ice Cover?

NASA Technical Reports Server (NTRS)

Tremblay, L.B.; Schmidt, G.A.; Pfirman, S.; Newton, R.; DeRepentigny, P.

2015-01-01

Ice-rafted sediments of Eurasian and North American origin are found consistently in the upper part (13 Ma BP to present) of the Arctic Coring Expedition (ACEX) ocean core from the Lomonosov Ridge, near the North Pole (approximately 88 degrees N). Based on modern sea-ice drift trajectories and speeds, this has been taken as evidence of the presence of a perennial sea-ice cover in the Arctic Ocean from the middle Miocene onwards. However, other high latitude land and marine records indicate a long-term trend towards cooling broken by periods of extensive warming suggestive of a seasonally ice-free Arctic between the Miocene and the present. We use a coupled sea-ice slab-ocean model including sediment transport tracers to map the spatial distribution of ice-rafted deposits in the Arctic Ocean. We use 6 hourly wind forcing and surface heat fluxes for two different climates: one with a perennial sea-ice cover similar to that of the present day and one with seasonally ice-free conditions, similar to that simulated in future projections. Model results confirm that in the present-day climate, sea ice takes more than 1 year to transport sediment from all its peripheral seas to the North Pole. However, in a warmer climate, sea-ice speeds are significantly faster (for the same wind forcing) and can deposit sediments of Laptev, East Siberian and perhaps also Beaufort Sea origin at the North Pole. This is primarily because of the fact that sea-ice interactions are much weaker with a thinner ice cover and there is less resistance to drift. We conclude that the presence of ice-rafted sediment of Eurasian and North American origin at the North Pole does not imply a perennial sea-ice cover in the Arctic Ocean, reconciling the ACEX ocean core data with other land and marine records.

Performance of PV panels for solar energy conversion at the South Pole

NASA Astrophysics Data System (ADS)

Peeran, Syed M.

Expanding research facilities at the Amundson-Scott South pole station require increased electric power generation. Presently, electric power generation is by diesel generators using the JP8 fuel. As the station is accessible only for a short supply period during the austral summer, there are limitations upon the supply of fuel for power generation. This makes it necessary to seriously consider the use of the renewable energy sources. Although there is no sunlight for six months in the year, abundant solar energy is available during the remaining 6 months because of the clear skies, the clarity of air and the low humidity at the south pole. As the buildings at the south pole are built either without windows or with only porthole type windows, large areas on the walls and the roof are available for mounting the photovoltaic (PV) panels. In addition there is unlimited space around the station for constructing a PV panel 'farm'. In this paper four types of PV panels are evaluated; the 2-axis tracking panels, vertical 1-axis tracking panels, fixed vertical panels on the walls of buildings and mounted outdoors, and fixed horizontal panels on the roofs of the buildings. Equations are developed for the power output in KW/sq. ft and annual energy in kWh/sq. ft for each type of panel. The equations include the effects of the inclination of the sun above the horizon, the movement of the sun around the horizon, the direct, reflected and diffused components of the solar radiation, the characteristics of the solar cells and the types of dc/ac inverters used to interface the output of the cells with the existing ac power. A conceptual design of a 150-kW PV generation system suitable for the south pole is also discussed in this paper.

Climatic Change over the 'Third Pole' from Long Tree-Ring Records

NASA Astrophysics Data System (ADS)

Cook, E.

2011-12-01

Climatic change over the Greater Himalayas and Tibetan Plateau, the 'Third Pole' of the world, is of great concern now as the Earth continues to warm at an alarming rate. While future climatic change over this region and its resulting impacts on humanity and the environment are difficult to predict with much certainty, knowing how climate has varied in the past can provide both an improved understanding of the range of variability and change that could occur in the future and the necessary context for assessing recent observed climatic change there. For this purpose, one of the best natural archives of past climate information available for study of the Third Pole environment is the changing pattern of annual ring widths found in long tree-ring chronologies. The forests of the Third Pole support many long-lived tree species, with some having life spans in excess of 1,000 years. This natural resource is steadily dwindling now due to continuing deforestation caused by human activity, but there is still enough remaining forest cover to produce a detailed network of long tree-ring chronologies for study of climate variability and change covering the past several centuries. The tree-ring records provide a mix of climate information, including that related to both temperature and precipitation. Examples of long drought-sensitive tree-ring records from the more arid parts of the Karakoram and Tibetan Plateau will be presented, along with records that primarily reflect changing temperatures in moister environments such as in Bhutan. Together they provide a glimpse of how climate of the Third Pole has changed over the past several centuries, the range of natural variability that could occur in the future independent of changes caused by greenhouse warming, and how changes during the latter part of the 20th century period of rapid global warming compare to the past.

LRO-LAMP Observations of Illumination Conditions in the Lunar South Pole

NASA Astrophysics Data System (ADS)

Mandt, K.; Greathouse, T. K.; Retherford, K. D.; Mazarico, E.; Gladstone, R.; Liu, Y.; Hendrix, A.; Hurley, D.; Lemelin, M.; Patterson, G. W.; Bowman-Cisneros, E.

2016-12-01

The south pole of the Moon is an area of great interest for space exploration and scientific research, because many low-lying regions are permanently shaded while adjacent topographic highs experience near constant sunlight. The lack of direct sunlight in permanently shaded regions (PSRs) provides cold enough conditions for them to potentially trap and retain large quantities of volatiles in their soils, while the locations that receive extended periods of sunlight could provide a reliable source of solar energy and relatively stable temperature conditions. Illumination conditions at the lunar south pole vary diurnally and seasonally, but on different timescales than days and seasons on the Earth. The most important advancements in understanding illumination conditions at the poles are provided by topographic mapping and illumination modeling. These efforts have provided estimates of the extent of PSRs and the percent of time that sunlit peaks are illuminated. They also help to constrain the thermal balance of the PSRs based on other sources of illumination. However, comparing model results with spacecraft observations can help to validate the models and provides ground truth for planning future exploration efforts. We have developed a new method for observing illumination conditions at the south pole using data taken by the LRO Lyman Alpha Mapping Project (LAMP), a far ultraviolet (FUV) imaging spectrograph. LAMP produces maps of the albedo of the upper 25-100 nm of lunar regolith using measurements of the brightness of reflected light relative to known light sources in daytime and nighttime conditions. Nighttime observations have been used previously to determine the abundance of surface frost within the PSRs and the surface porosity of regolith within the PSRs. The maps that have been used for these studies excluded scattered sunlight by restricting observations to nighttime conditions when the solar zenith angle is greater than 91°. However, by producing maps of the PSRs using data that was excluded from these previous studies we are able to observe scattering of far-UV sunlight at night within the PSRs.

Designation of the anterior/posterior axis in pregastrula Xenopus laevis.

PubMed

Lane, M C; Sheets, M D

2000-09-01

A new fate map for mesodermal tissues in Xenopus laevis predicted that the prime meridian, which runs from the animal pole to the vegetal pole through the center of Spemann's organizer, is the embryo's anterior midline, not its dorsal midline (M. C. Lane and W. C. Smith, 1999, Development 126, 423-434). In this report, we demonstrate by lineage labeling that the column 1 blastomeres at st. 6, which populate the prime meridian, give rise to the anterior end of the embryo. In addition, we surgically isolate and culture tissue centered on this meridian from early gastrulae. This tissue forms a patterned head with morphologically distinct ventral and dorsal structures. In situ hybridization and immunostaining reveal that the cultured heads contain the anterior tissues of all three germ layers, correctly patterned. Regardless of how we dissect early gastrulae along meridians running from the animal to the vegetal pole, both the formation of head structures and the expression of anterior marker genes always segregate with the prime meridian passing through Spemann's organizer. The prime meridian also gives rise to dorsal, axial mesoderm, but not uniquely, as specification tests show that dorsal mesoderm arises in fragments of the embryo which exclude the prime meridian. These results support the hypothesis that the midline that bisects Spemann's organizer is the embryo's anterior midline. Copyright 2000 Academic Press.

Results of paleomagnetic study of Early Proterozoic rocks in the Baikal Range of the Siberian craton

NASA Astrophysics Data System (ADS)

Vodovozov, V. Yu.; Didenko, A. N.; Gladkochub, D. P.; Mazukabzov, A. M.; Donskaya, T. V.

2007-10-01

This paper presents paleomagnetic results obtained from the study of Early Proterozoic rocks in the Baikal Range of the Siberian craton, namely, the 1850 1880-Ma volcanicalstic rocks of the Akitkanskian series of the North Baikal volcanic-plutonic belt) and 1674-Ma basic dikes of the Chaya complex within the massif. The data of this work are used to reconstruct the development of the Siberian craton structure in the Early Precambrian. The projections of the inferred paleomagnetic directions onto a sphere form S (southern) and W (western) groups of vectors of characteristic magnetization components. The S group consists of three clusters representing primary magnetization components belonging to different time levels of the end of the Early Proterozoic. The W group is represented by directions associated with a metachronous magnetization probably acquired during the Riphean. Four paleomagnetic poles are obtained. Two of them that can be regarded as key poles correspond to time levels of 1875 and 1670 Ma (the Early Proterozoic). The two other poles can be used for a detailed reconstruction of the Proterozoic segment of the Siberian apparent polar wander path. The data presented in the paper indicate that the formation of the southern Siberian craton structure was accomplished at the end of the Early Proterozoic, which resulted in a synchronous motion of different blocks composing the southern flank of the craton (in particular, the Sharyzhalgai and Baikal Ranges).

Sphenoid dysplasia in neurofibromatosis type 1: a new technique for repair.

PubMed

Concezio, Di Rocco; Amir, Samii; Gianpiero, Tamburrini; Luca, Massimi; Mario, Giordano

2017-06-01

Sphenoid bone dysplasia in neurofibromatosis type 1 is characterized by progressive exophthalmos and facial disfiguration secondary to herniation of meningeal and cerebral structures. We describe a technique for reconstruction of the sphenoid defect apt at preventing or correcting the ocular globe dislocation. After placement of spinal cerebrospinal fluid drainage to reduce intracranial pressure, the temporal pole is posteriorly dislocated extradurally. The greater sphenoid wing defect is identified. A titanium mesh covered by lyophilized dura, modeled in a curved fashion, is interposed between the bone defect and the cerebro-meningeal structures with its convex surface over the retracted temporal pole. The particular configuration of the titanium mesh allows a self-maintaining position due to the pressure exerted by the brain over its convex central part with its lateral margins consequently pushed and self-anchored against the medial and lateral walls of the temporal fossa. Screw fixation is not needed. The technique utilized in four cases proved to be reliable at the long-term clinical and neuroradiological controls (6 to 19 years). Sphenoid bone dysplasia in NF1, resulting in proptosis and exophthalmos, is usually progressive. It can be surgically repaired using a curved titanium mesh with the convexity faced to the temporal pole that is in the opposite fashion from all the techniques previously introduced. When utilized early in life, the technique can prevent the occurrence of the orbital and facial disfiguration.

Single phase two pole/six pole motor

DOEpatents

Kirschbaum, Herbert S.

1984-01-01

A single phase alternating current two pole/six pole motor is provided with a main stator winding having six coils disposed unequally around the periphery of the machine. These coils are divided into two groups. When these groups are connected such that their magnetomotive forces are additive, two pole motor operation results. When the polarity of one of the groups is then reversed, six pole motor operation results. An auxiliary stator winding which is similar to the main stator winding is displaced from the main stator winding by 90 electrical degrees on a two pole basis.

Use of geometric properties of landmark arrays for reorientation relative to remote cities and local objects.

PubMed

Mou, Weimin; Nankoo, Jean-François; Zhou, Ruojing; Spetch, Marcia L

2014-03-01

Five experiments investigated how human adults use landmark arrays in the immediate environment to reorient relative to the local environment and relative to remote cities. Participants learned targets' directions with the presence of a proximal 4 poles forming a rectangular shape and an array of more distal poles forming a rectangular shape. Then participants were disoriented and pointed to targets with the presence of the proximal poles or the distal poles. Participants' orientation was estimated by the mean of their pointing error across targets. The targets could be 7 objects in the immediate local environment in which the poles were located or 7 cities around Edmonton (Alberta, Canada) where the experiments occurred. The directions of the 7 cities could be learned from reading a map first and then from pointing to the cities when the poles were presented. The directions of the 7 cities could also be learned from viewing labels of cities moving back and forth in the specific direction in the immediate local environment in which the poles were located. The shape of the array of the distal poles varied in salience by changing the number of poles on each edge of the rectangle (2 vs. 34). The results showed that participants regained their orientation relative to local objects using the distal poles with 2 poles on each edge; participants could not reorient relative to cities using the distal pole array with 2 poles on each edge but could reorient relative to cities using the distal pole array with 34 poles on each edge. These results indicate that use of cues in reorientation depends not only on the cue salience but also on which environment people need to reorient to.

Sod Blocks, Lodge Poles, and Cornerstones: On Teaching Cultural History and Structure through Puppetry Arts.

ERIC Educational Resources Information Center

Wheeler, David

1999-01-01

Describes the use of puppet theater in an Alaskan elementary school focusing on the design and implementation of a play on the history of Alaska. Reports that the play's focus was on the change in architectural structures as a means to explore events that transformed Alaska. Provides recommendations for a similar project. (CMK)

High-Fidelity Down-Conversion Source for Secure Communications Using On-Demand Single Photons

NASA Technical Reports Server (NTRS)

Roberts, Tony

2015-01-01

AdvR, Inc., has built an efficient, fully integrated, waveguide-based source of spectrally uncorrelated photon pairs that will accelerate research and development (R&D) in the emerging field of quantum information science. Key to the innovation is the use of submicron periodically poled waveguides to produce counter propagating photon pairs, which is enabled by AdvR's patented segmented microelectrode poling technique. This novel device will provide a high brightness source of down-conversion pairs with enhanced spectral properties and low attenuation, and it will operate in the visible to the mid-infrared spectral region. A waveguide-based source of spectrally and spatially pure heralded photons will contribute to a wide range of NASA's advanced technology development efforts, including on-demand single photon sources for high-rate spaced-based secure communications.

Configuration of the magnetic field and reconstruction of Pangaea in the Permian period.

PubMed

Westphal, M

1977-05-12

The virtual geomagnetic poles of Laurasia and Gondwanaland in the Carboniferous and Permian periods diverge significantly when these continents are reassembled according to the fit calculated by Bullard et al. Two interpretations have been offered: Briden et al. explain these divergences by a magnetic field configuration very different from that of a geocentric axial dipole; Irving (and private communication), Van der Voo and French(4) suggest a different reconstruction and it is shown here that these two interpretations are not incompatible and that the first may help the second.

A Cloudy Day on Mars

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 23 April 2002) The Science This image, centered near 49.7 N and 43.0 W (317.0 E), displays splotchy water ice clouds that obscure the surface. Most of Mars was in a relatively clear period when this image was acquired, which is why many of the other THEMIS images acquired during the same period do not have obvious signs of atmospheric dust or water ice clouds. This image is far enough north to catch the edge of the north polar hood that develops during the northern winter. This is a cap of water ice and CO₂ ice clouds that form over the Martian north pole. Mars has a number of interesting atmospheric phenomena which THEMIS will be able to view in addition to water ice clouds, including dust devils, dust storms, and tracking atmospheric temperatures with the infrared camera. The Story Anyone who's been on an airplane in a storm knows how clouds on Earth can block the view below. The thin water ice clouds on Mars might make things slightly blurry, but at least we can still see the surface. While the surface features may not be as clear in this image, it's actually kind of fascinating to see clouds at work, because we can get a sense of how the north pole on Mars influences the weather and the climate. In this image, the north pole is responsible for the presence of the clouds. Made of water ice and carbon dioxide, these clouds 'mist out' in a atmospheric 'hood' that caps the surface during the northern Martian winter, hiding it from full view of eager observers here on Earth.

Permanent magnet machine and method with reluctance poles and non-identical PM poles for high density operation

DOEpatents

Hsu, John S.

2010-05-18

A method and apparatus in which a stator (11) and a rotor (12) define a primary air gap (20) for receiving AC flux and at least one source (23, 40), and preferably two sources (23, 24, 40) of DC excitation are positioned for inducing DC flux at opposite ends of the rotor (12). Portions of PM material (17, 17a) are provided as boundaries separating PM rotor pole portions from each other and from reluctance poles. The PM poles (18) and the reluctance poles (19) can be formed with poles of one polarity having enlarged flux paths in relation to flux paths for pole portions of an opposite polarity, the enlarged flux paths communicating with a core of the rotor (12) so as to increase reluctance torque produced by the electric machine. Reluctance torque is increased by providing asymmetrical pole faces. The DC excitation can also use asymmetric poles and asymmetric excitation sources. Several embodiments are disclosed with additional variations.

STRUCTURE IN THE ROTATION MEASURE SKY

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

Stil, J. M.; Taylor, A. R.; Sunstrum, C.

2011-01-01

An analysis of structure in rotation measure (RM) across the sky based on the RM catalog of Taylor et al. is presented. Several resolved RM structures are identified with structure in the local interstellar medium, including radio loops I, II, and III, the Gum nebula, and the Orion-Eridanus superbubble. Structure functions (SFs) of RM are presented for selected areas, and maps of SF amplitude and slope across the sky are compared with H{alpha} intensity and diffuse polarized intensity. RM variance on an angular scale of 1{sup 0} is correlated with length of the line of sight through the Galaxy, withmore » a contribution from local structures. The slope of the SFs is less concentrated to the Galactic plane and less correlated with length of the line of sight through the Galaxy, suggesting a more local origin for RM structure on angular scales {approx}10{sup 0}. The RM variance is a factor of {approx}2 higher toward the South Galactic Pole than toward the North Galactic Pole, reflecting a more wide-spread asymmetry between the northern and southern Galactic hemispheres. Depolarization of diffuse Galactic synchrotron emission at latitudes <30{sup 0} can be explained largely by Faraday dispersion related to small-scale variance in RM, but the errors allow a significant contribution from differential Faraday rotation along the line of sight.« less

Amalgamation of East Eurasia Since Late Paleozoic: Constraints from the Apparent Polar Wander Paths of the Major China Blocks

NASA Astrophysics Data System (ADS)

Wu, L.; Kravchinsky, V. A.; Potter, D. K.

2014-12-01

It has been a longstanding challenge in the last few decades to quantitatively reconstruct the paleogeographic evolution of East Eurasia because of its great tectonic complexities. As the core region, the major China cratons including North China Block, South China Block and Tarim Block hold the key clues for the understanding of the amalgamation history, tectonic activities and biological affinity among the component blocks and terranes in East Eurasia. Compared with the major Gondwana and Laurentia plates, however, the apparent polar wander paths of China are not well constrained due to the outdated paleomagnetic database and relatively loose pole selection process. With the recruitment of the new high-fidelity poles published in the last decade, the rejection of the low quality data and the strict implementation of Voo's grading scheme, we build an updated paleomagnetic database for the three blocks from which three types of apparent polar wander paths (APWP) are computed. Version 1 running mean paths are constructed during the pole selection and compared with those from the previous publications. Version 2 running mean and spline paths with different sliding time windows are computed from the thoroughly examined poles to find the optimal paths with the steady trend, reasonable speed for the polar drift and plate rotation. The spline paths are recommended for the plate reconstructions, however, considering the poor data coverage during certain periods. Our new China APWPs, together with the latest European reference path, the geological, geochronological and biological evidence from the studied Asian plates allow us to reevaluate the paleogeographic and tectonic history of East Eurasia.

Seasonal evolution of Titan’s stratosphere near the poles from Cassini/CIRS data

NASA Astrophysics Data System (ADS)

Coustenis, Athena; Jennings, Donald E.; Achterberg, Richard K.; Bampasidis, Georgios; Cottini, Valeria; Nixon, Conor A.; Flasar, F. Michael

2017-10-01

We report on the monitoring of the seasonal evolution near Titan’s poles. Since 2010, we observe at Titan’s south pole a strong temperature decrease and the onset of a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously observed only at high northern latitudes (Coustenis et al. 2016 and references therein). This is due to the transition of Titan’s seasons from northern winter in 2002 to northern summer in 2017 and, at the same time, the advent of winter in the south pole, during which time species with longer chemical lifetimes remain in the north for a little longer undergoing slow photochemical destruction, while those with shorter lifetimes disappear, reappearing in the south. An opposite effect has been expected in the North, but not observed with any significant certainty until 2016. We present here an analysis of nadir spectra acquired by Cassini/CIRS (Jennings et al., 2017) at high resolution in the past years and describe the newly observed decrease in chemical abundances of the components in the North. From 2013 until 2016, the Northern polar region has shown a temperature increase of 10 K, while the South had shown a more significant decrease in a similar period of time. The chemical content in the North is finally showing a clear depletion for most molecules since 2015 (Coustenis et al., 2017).References: Coustenis et al., 2016, Icarus 270, 409-420 ; Coustenis et al., 2017, in preparation; Jennings et al., 2017, Applied Optics 56, no 18, 5274-5294.

Holocene Sea-Levels from Greenland to Antarctica: A Pole-to-Pole Transect of Sea Level History

NASA Astrophysics Data System (ADS)

Horton, Benjamin; Peltier, William; Roy, Keven; Ashe, Erica; Shaw, Tim; Engelhart, Simon; Khan, Nicole; Kopp, Robert; Simkins, Lauren; Vacchi, Matteo; Woodroffe, Sarah

2017-04-01

The Holocene is the most recent period during which natural temperature variability predominates and, therefore, provides an important paleo perspective for understanding the climate:sea-level relationship prior to anthropogenic modification of the climate system. But our understanding of Holocene sea level is limited by a lack of a standard protocol that incorporates full consideration of vertical and temporal uncertainty for each sea-level index point. We have compiled a Holocene RSL database of 3000 validated sea-level index points from Greenland, North American Atlantic coast, Caribbean, South American Atlantic coast and Antarctica. The databases were collated using a formalized and consistent methodology to facilitate the development and comparison of regional RSL records. The database also includes information relevant to sediment compaction, and modelling of both modern-day and paleotidal ranges. We develop a spatio-temporal empirical hierarchical model to compare regional RSL histories and estimate rates of change. Holocene RSL history from near-field regions (e.g., Antarctica, Greenland and Canada) reveal a complex pattern of RSL fall from a maximum marine limit due to the net effect of eustatic sea-level rise and glacio-isostatic uplift with rates of RSL fall as great as 70 ± 5 m/ka (East Hudson Bay). Intermediate field regions (e.g., North American mid-Atlantic coast) display variable rates of RSL rise from the cumulative effect of eustatic and isostatic factors. Fast rates of RSL rise (up to 10 ± 4m/ka; New Jersey) are found in the early Holocene in regions near the center of forebulge collapse. Far-field RSL records (South American Atlantic coast) exhibit a mid-Holocene highstand, the timing and magnitude of which varies between 8 and 4 ka and <1 and 6 m, respectively. We compare RSL histories with the predictions from two recent models of the Glacial Isostatic Adjustment (GIA) process, namely the ICE-6GC (VM5a) model of Peltier et al. (2015) and the ICE-7G_NA (VM7) model of Roy and Peltier (2017 in press). Although the fit of these models to the wide range of inferred RSL histories along the pole-to-pole transect is very high quality, unexplained signals are identified in several restricted regions upon which work is continuing. It is remarkable that a spherically symmetric model of the internal viscoelastic structure is able to reconcile the wide range of RSL signals observed.

Anchor Bolt Behavior in ASR/DEF-Damaged Drilled Shafts.

DOT National Transportation Integrated Search

2007-02-01

The primary objective of this research is to evaluate the effect of Alkali-Silica Reaction (ASR) and Delayed Ettringite Formation (DEF) on the structural performance of High Mast Illumination Pole (HMIP) foundations and if needed, to recommend a poss...

Proof of concept for using unmanned aerial vehicles for high mast pole and bridge inspections.

DOT National Transportation Integrated Search

2015-06-01

Bridges and high mast luminaires (HMLs) are key components of transportation infrastructures. Effective inspection : processes are crucial to maintain the structural integrity of these components. The most common approach for : inspections is visual ...

NASA Spacecraft Images Oregon Wildfire

NASA Image and Video Library

2012-09-21

This image, acquired by NASA Terra spacecraft, is of the Pole Creek fire southwest of Sisters, Ore., which had grown to 24,000 acres as of Sept. 20, 2012. No structures have been destroyed, and the fire is mostly confined to the national forest.

The caprine abomasal microbiome

USDA-ARS?s Scientific Manuscript database

Parasitism is considered the number one health problem in small ruminants. The barber's pole worm Haemonchus contortus infection in goats elicits a strong host immune response. However, the effect of the parasitic infection on the structure and function of the gut microbiome remains largely unknown....

Paleomagnetism of baked sedimentary rocks in the Newark and Culpeper basins: Evidence for the J1 cusp and significant Late Triassic apparent polar wander from the Mesozoic basins of North America

NASA Astrophysics Data System (ADS)

Kodama, Kenneth P.; Cioppa, Maria T.; Sherwood, Elizabeth; Warnock, Andrew C.

1994-08-01

A paleomagnetic study of 14 sites in the baked sedimentary rocks of the Newark basin Passaic Formation in southeastern Pennsylvania reveals two types of magnetic behavior. Dark gray-colored, baked sedimentary rocks have peak unblocking temperatures of 640°C, high magnetic intensities, and shallow, normal polarity, northeasterly directions. Light gray-colored rocks have peak unblocking temperatures of less than 580°C, low magnetic intensities, and intermediate inclination, normal polarity, northwesterly directions. The low unblocking temperature magnetizations are secondary magnetizations which have declinations similar to but are shallower than the B remagnetization observed by Witte and Kent (1991) throughout the Newark basin. The discrepancy may be due to "underprinting" by an unresolved primary magnetization. The low unblocking temperature magnetization was probably acquired by growth of secondary magnetite during a hydrothermal event, as postulated by Sutter (1988), based on geochronologic data. The high unblocking temperature magnetization is significantly prefolding. Both the low-peak unblocking temperature magnetization and the high-peak unblocking temperature magnetization suggest a 15° counterclockwise block rotation of the Sassamansville syncline. If this rotation is removed from the high unblocking temperature sites collected around the fold, a stronger passage of the fold test results. Six sites were also collected from baked sediments and one site from diabase in northern Virginia's Culpeper basin, since Sutter's geochronological work indicated that the intrusives in the Culpeper basin are coeval to the Newark basin intrusives. Virtual geomagnetic poles (VGPs), based on the tilt-corrected, high-temperature Newark basin magnetizations, were compared with the VGPs calculated from the site means of a high-temperature magnetization isolated from baked sedimentary rocks in the Culpeper basin and to the magnetizations reported by Raymond (1982) from dikes and sills. In this comparison the in situ Culpeper poles agreed with the prefolding Newark poles significantly better than the prefolding Culpeper poles. This result indicates that Culpeper intrusives erupted into already tilted sedimentary rocks. The paleomagnetic pole determined from the combined Culpeper baked sediments, dikes, and sills (in situ coordinates) and the Newark basin baked sediments (tilt-corrected coordinates) lies at 60°N, 69°E and is of 201 Ma age. This latest Triassic/earliest Jurassic pole, when combined with the Newark basin Carnian results (Witte and Kent, 1989) and Norian results (Witte et al., 1991) corrected for a counterclockwise block rotation (Kodama et al., 1994), provides a record of significant polar wander from eastern North America's Mesozoic basins for the Late Triassic. This is consistent with observations made for a similar time period from rocks on the Colorado Plateau (Bazard and Butler, 1991). Comparison of the Newark/Culpeper pole to similar age poles from the Kayenta (Bazard and Butler, 1991) and Moenave Formations (Ekstrand and Butler, 1989) only requires small amounts (5°) of Colorado Plateau rotation. The pole also provides the first well-dated evidence of the Jl cusp in North American apparent polar wander from rocks not located on the Colorado Plateau, thus giving strong support for the usefulness of paleomagnetic Euler pole analysis of apparent polar wander.

Milankovic's "end of the world"

NASA Astrophysics Data System (ADS)

Milicevic, Vlado

2009-07-01

The Milankovic's numerical trajectory of secular changes of pole's rotation has shown that its latest positions in positive infinity can be observed on the North Pole of the Siberian plate. Milankovic with his discovers 'end of the world' or total end of activity in asthenosphere. In other words, he discovers plate tectonics of pole's (convergence, divergence, and transform movement), earthquakes, subduction zones, sea floor spreading, etc. This is not just the end of the atmosphere existence, water or life on the planet, but also a geodynamic, co-mechanic and co-climatological climax. This is the beginning of the ice ages. The pole of rotation, by Milankovic, reaches φ = +49° 34'; λ = +65° 16' for the Northern Hemisphere or φ = -130° 26'; λ = -65° 16' for Southern Hemisphere. Based on this data and according to the pole spreading of lithosphere, it is possible to recognize future climatic zones under geographical latitudes and longitudes. These are also known as the green zones, the most endangered continental places. The entire Europe and the parts of Asia will be under ice. Studying the continent of North America we can observe only a part of Canada is under ice (up to 60 of geographical longitude). This will happen due to continuous Atlantic sea floor spreading, and also due to the counterclockwise rotation of the North American plate. This will cause the continents to move away from the North Pole. The problem of some time units and numerical secular positions, Milankovic calculated and graphically presented, still stands as one of the greatest planetary enigmas. Their close picture is available through geophysical, geodetic, and mathematical methods, satellites, stations on the Earth's surface and also through practicing new technology. The mentioned "end of the world" does not present the end of the Earth's cosmic phase. It does not correspond to astronomical age determinants and further planetary deviation. Milankovic has experienced and mathematically presented cinematic planetary model of continents. He further included the water areas, atmosphere, and living beings. The Milankovic's "end of the world" is just an end of the pole's tectonics, critical temperatures and fluidly fall in the atmosphere. Also, it is the ending of the seismic phase, rift genesis, subdaction, and radioactivity. However, all together will not have any further consequences on the other structures, especially not on the Earth's nucleus. The Milankovic's end of the world resembles the minimization of mechanical secular changes of the pole rotation. The Earth's rotation itself stays unchanged or barely changed.

Sensitive Infrared Signal Detection by Upconversion Technique

NASA Technical Reports Server (NTRS)

Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

2014-01-01

We demonstrated upconversion assisted detection of a 2.05-micron signal by sum frequency generation to generate a 700-nm light using a bulk periodically poled lithium niobate crystal. The achieved 94% intrinsic upconversion efficiency and 22.58% overall detection efficiency at a pW level of 2.05 micron pave the path to detect extremely weak infrared (IR) signals for remote sensing applications.