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Long Range (long + range)
Terms modified by Long Range Selected AbstractsOptimization of the Magnetic Properties of FePd Alloys by Severe Plastic Deformation,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Abdelahad Chbihi Abstract A FePd alloy was nanostructured by severe plastic deformation following two different routes: ordered and disordered states were processed by high pressure torsion (HPT). A grain size in a range of 50 to 150,nm is obtained in both cases. Severe plastic deformation induces some significant disordering of the long range ordered L10 phase. However, transmission electron microscopy (TEM) data clearly show that few ordered nanocrystals remain in the deformed state. The deformed materials were annealed to achieve nanostructured long range ordered alloys. The transformation proceeds via a first order transition characterized by the nucleation of numerous ordered domains along grain boundaries. The influence of the annealing conditions (temperature and time) on the coercivity was studied for both routes. It is demonstrated that starting with the disorder state prior to HPT and annealing at low temperature (400,°C) leads to the highest coercivity (about 1.8,kOe). [source] Seismological identification of the 1998 May 28 Pakistan nuclear testGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2002D. Bowers Summary On 1998 May 28 Pakistan announced that it had conducted an underground nuclear test. Here we assess whether seismological data, recorded by the International Monitoring System (IMS) being set up to help verify the Comprehensive Test Ban Treaty (CTBT), can be used to identify the Pakistani test as a possible underground explosion. The prototype International Data Centre (pIDC) automatically determined the network-averaged body wave and surface wave magnitudes to be 4.9 and 3.6, respectively. One of the most reliable methods of identifying possible underground explosions is the mb : Ms criterion. However, mb : Ms is calibrated using conventional magnitudes from historical earthquakes and explosions. We calculate , in the conventional way, using P waves from the Pakistani test recorded by a simulated standard short-period seismograph and read by an experienced analyst. We also analyse the three components of the surface waves from the Pakistani test to confirm that these are correctly associated, and calculate . On mb : Ms the Pakistani test falls between the historical Eurasian underground explosion and earthquake populations. Thus, while the source may arouse suspicion on mb : Ms, its signature is typical of both explosions and deep-lithospheric Eurasian earthquakes. The vast majority of the seismic P signals from the Pakistani test, recorded at long range, are complex. However, simple P seismograms are recorded by at least three of the IMS stations. Analysis, using the relative amplitude method, of three of the simple P seismograms suggests that the source is shallow (less than 5 km). We conclude that the combination of the mb : Ms signature and shallow depth are sufficient to classify the Pakistani test as a possible explosion. Under the CTBT an on-site inspection would be required to determine whether the explosion was nuclear. [source] High-resolution millimeter-wave radar systems for visualization of unstructured outdoor environmentsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2006Graham Brooker This paper examines the use of millimeter-wave radar systems for visualization and navigation in unstructured outdoor environments. Three types of radar systems are described. The first is a long range, 94 GHz, frequency modulated interrupted continuous wave radar which is capable of producing two-dimensional (2D) reflectivity images to a range of more than 3 km. This is intended for use in long-range path planning. The second is a class of medium range 77 GHz frequency modulated continuous wave (FMCW) radar with two axis mirror scanners which is capable of producing high resolution threedimensional (3D) imagery out to 500 m at a reasonably slow frame rate. The final class also operates using the FMCW principle, but at 94 GHz, to produce high resolution 2D and 3D images out to about 50 m at a much higher update rate. These shorter range sensors may be used to determine the traversability of the local terrain. The outputs produced by the different classes of radar are examined and the paper considers their advantages when compared to other sensors such as vision and scanning laser. Using radar images, the final section compiles rules for interpreting radar reflectivity images from a path-planning perspective. © 2006 Wiley Periodicals, Inc. [source] New Traversability Indices and Traversability Grid for Integrated Sensor/Map-Based NavigationJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2003Homayoun Seraji This paper presents new measures of terrain traversability at short range and long range of a mobile robot; namely, local and global traversability indices. The sensor-based local traversability index is related by a set of linguistic rules to large obstacles and surface softness within a short range of the robot measured by on-board sensors. The map-based global traversability index is obtained from the terrain topographic map, and is based on major surface features such as hills and lakes within a long range of the robot. These traversability indices complement the mid-range sensor-based regional traversability index introduced earlier. Each traversability index is represented by four fuzzy sets with the linguistic labels {POOR, LOW, MODERATE, HIGH}, corresponding to surfaces that are unsafe, moderately-unsafe, moderately-safe, and safe for traversal, respectively. The global terrain analysis also leads to the new concepts of traversability map and traversability grid for representation of terrain quality based on the global map information. The traversability indices are used in two sensor-based traverse-local and traverse-regional behaviors and one map-based traverse-global behavior. These behaviors are integrated with a map-based seek-goal behavior to ensure that the mobile robot reaches its goal safely while avoiding both sensed and mapped terrain hazards. This provides a unified system in which the two independent sources of terrain quality information, i.e., prior maps and on-board sensors, are integrated together for reactive robot navigation. The paper is concluded by a graphical simulation study. © 2003 Wiley Periodicals, Inc. [source] Numerical simulation of anisotropic elastic fields of a GaAs/GaAs twist boundaryPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2007Salah Madani Abstract Self-assembled nanostructures are particularly interesting for optoelectronic and photonic applications, especially on silicon and GaAs substrates. Nevertheless, their long-range spatial distribution is random, their density is difficult to control, their size distribution can be large and their shapes can be different. By overcoming these drawbacks, it should be possible to improve the performances of existing devices or to fabricate new ones. This work studies the possibility to order on a long range self-assembled nanostructures on a GaAs substrate, by means of the elastic fields induced at the surface by shallowly buried periodic dislocation networks. The needed strain and stress fields, generated by a square network of screw dislocations located between a finite layer of GaAs bonded onto a semi-infinite GaAs substrate, are calculated using anisotropic elasticity. The results obtained are compared to those obtained using isotropic elasticity. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ambient temperature and sound power of cicada calling songs (Hemiptera: Cicadidae: Tibicina)PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003Jérôme Sueur Abstract., Male cicadas produce a loud calling song that attracts females at long range. In some cases, ambient temperature has been shown to have an effect on the temporal structure of this acoustic signal. Here, a positive correlation is reported for the first time between the ambient temperature and the sound power of the calling song. This relationship is illustrated in three species of the Palaearctic genus Tibicina: Tibicina corsica fairmairei Boulard, Tibicina garricola Boulard and Tibicina tomentosa Olivier. It is suggested that the males thermoregulate behaviourally. The minimal ambient temperature range that the Tibicina species need to call is 22,24 °C. The effect of ambient temperature on calling song power is assumed to be the result of thermal effects in the response of the acoustic system (i.e. muscle activity of the acoustic system being temperature-dependent). Inter-individual and interspecific differences in calling song power are interpreted in the general context of the Tibicina sound behaviour. [source] Structure determination of a Galectin-3,carbohydrate complex using paramagnetism-based NMR constraintsPROTEIN SCIENCE, Issue 7 2008Tiandi Zhuang Abstract The determination of the location and conformation of a natural ligand bound to a protein receptor is often a first step in the rational design of molecules that can modulate receptor function. NMR observables, including NOEs, often provide the basis for these determinations. However, when ligands are carbohydrates, interactions mediated by extensive hydrogen-bonding networks often reduce or eliminate NOEs between ligand and protein protons. In these cases, it is useful to look to other distance- and orientation-dependent observables that can constrain the geometry of ligand,protein complexes. Here we illustrate the use of paramagnetism-based NMR constraints, including pseudo-contact shifts (PCS) and field-induced residual dipolar couplings (RDCs). When a paramagnetic center can be attached to the protein, field-induced RDCs and PCS reflect only bound-state properties of the ligand, even when averages over small fractions of bound states and large fractions of free states are observed. The effects can also be observed over a long range, making it possible to attach a paramagnetic center to a remote part of the protein. The system studied here is a Galectin-3,lactose complex. A lanthanide-binding peptide showing minimal flexibility with respect to the protein was integrated into the C terminus of an expression construct for the Galectin-3,carbohydrate-binding domain. Dysprosium ion, which has a large magnetic susceptibility anisotropy, was complexed to the peptide, making it possible to observe both PCSs and field-induced RDCs for the protein and the ligand. The structure determined from these constraints shows agreement with a crystal structure of a Galectin-3,N -acetyllactosamine complex. [source] Application of NMR, molecular simulation, and hydrodynamics to conformational analysis of trisaccharides,BIOPOLYMERS, Issue 4 2003Ann M. Dixon Abstract The preferred conformations and conformational flexibilities of the trisaccharides ,-D-Glcp -(1,2)-,-D-Glcp -(1,3)-,-D-Glcp -OMe (I) and ,-D-Glcp -(1,3)[,-D-Glcp -(1,4)]-,-D-Glcp -OMe (II) in aqueous solution were determined using nuclear magnetic resonance (NMR) spectroscopy, molecular dynamics (MD) and Langevin dynamics (LD) simulations, and hydrodynamics calculations. Both trisaccharides have a vicinal substitution pattern in which long range (nonsequential) interactions may play an important role. LD simulation at 600 K indicated that the all- syn conformation predominated, though other conformations were apparent. NOE data and MD and LD simulations at 298 K all indicated that trisaccharide I is a single all- syn conformer in solution. Given that previous studies showed evidence of anti -conformers in ,-D-Glcp -(1,2)-,-D-Glcp -(1,3)-,-D-Glcp -OMe, this result provides an example of how changing the anomeric configuration of one residue from , to , can make an oligosaccharide more rigid. Discrepancies in inter-ring distances obtained by experiment and by simulation of the all- syn conformer suggest the presence of an anti -, conformation at the ,-(1,4)-linkage for II. A combined analysis of measured and calculated translational diffusion constants and 13C T1 relaxation times yield order parameters of 0.9 for each trisaccharide. This implies that any interconversion among conformations is significantly slower than tumbling. Anisotropies of approximately 1.6 and 1.3 calculated for I and II, respectively, are consistent with the observed relatively flat T1 profiles because the tumbling is not in the motional narrowing regime. Published 2003 Wiley Periodicals, Inc. Biopolymers 69: 448,460, 2003 [source] | ||||||||||