Narrow Corners Research Articles

Geofencing Motion Planning for Unmanned Aerial Vehicles Using an Anticipatory Range Control Algorithm

This paper presents a range control approach for implementing hard geofencing for unmanned air vehicles (UAVs), and especially remotely piloted versions (RPVs), via a proposed anticipatory range calculator. The approach employs turning circle intersection tests that anticipate the fence perimeter on approach. This ensures the vehicle turns before penetrating the geofence and remains inside the allowable operational airspace by accounting for the vehicles’ turning dynamics. Allowance is made for general geozone shapes and locations, including those located at the problematic poles and meridians where nonlinear angle mapping is dealt with, concave geozones, narrow corners with acute internal angles, and transient turn dynamics. The algorithm is shown to prevent any excursions using a high-fidelity simulation of a small remotely piloted vehicle. The algorithm relies on a single tuning parameter which can be determined from the closed-loop rise time in the aircraft’s roll command tracking.

Impact of recent (g − 2)μ measurement on the light CP-even Higgs scenario in general Next-to-Minimal Supersymmetric Standard Model

The General Next-to-Minimal Supersymmetric Standard Model (GNMSSM) is an attractive theory that is free from the tadpole problem and the domain-wall problem of Z3-NMSSM, and can form an economic secluded dark matter (DM) sector to naturally predict the DM experimental results. It also provides mechanisms to easily and significantly weaken the constraints from the LHC search for supersymmetric particles. These characteristics enable the theory to explain the recently measured muon anomalous magnetic moment, (g − 2)μ, in a broad parameter space that is consistent with all experimental results and at same time keeps the electroweak symmetry breaking natural. This work focuses on a popular scenario of the GNMSSM in which the next-to-lightest CP-even Higgs boson corresponds to the scalar discovered at the Large Hadron Collider (LHC). Both analytic formulae and a sophisticated numerical study show that in order to predict the scenario without significant tunings of relevant parameters, the Higgsino mass μtot ≲ 500 GeV and tan β ≲ 30 are preferred. This character, if combined with the requirement to account for the (g − 2)μ anomaly, will entail some light sparticles and make the LHC constraints very tight. As a result, this scenario can explain the muon anomalous magnetic moment in very narrow corners of its parameter space.

Systematic Approach for Static Steering Effort Reduction through Linkages Optimization in Small Commercial Vehicles (SCV)

The steering system design of a vehicle is of utmost importance as it not only acts as an interface between the driver and the entire vehicle but also is one of the key vehicle sub system which accounts for vehicle overall performance including vehicle handling and stability. With the recent infrastructure development and changes been witnessed in doing commercial vehicle business to hub and spoke and to door to door logistics delivery are expecting improved vehicle performance particularly in small and light commercial vehicles segments (SCV and LCV) where the business demands are more for the movement of vehicle in narrow city lanes and sharp corners. Also, now driver comfort is considered one of the key factors before purchasing any commercial vehicle. Thus, having power steering in SCV’s and LCV’s has not only become a mandate but also the vehicle steering system performance should be such that the driver is easily able to maneuver the vehicle in narrow city lanes and corners. Through this paper a methodology has been derived wherein factors contributing for achieving static lock to lock maneuverability in a power steering vehicle are analyzed without overdesigning the hydraulic power assistance of the vehicle. The approach mainly focuses on LH/RH symmetric hydraulic pressure build up in the system by critically designing the steering system linkages hard points such as drop arm length, drop arm SAP angle, steer arm length, track rod arm’s length. Also, this study ensures that the derived hard points not only enhances hydraulic assistance in the steering system but also ensures vehicle to have least turning circle diameter (TCD) and enhanced tire life by having least Ackermann error.

Risks and Threats to Web Applications and Their Preventions : A Theoretical Study on Vital Risks and Threats

With the rapid evolution of technology, almost every business is now online connecting them to the widest and narrow corners of the world. Therefore, instead of physical security, their online security is a pivotal concern the business which all depends on the web applications security. Web application attacks and their risks have become normal since past many years, and the security of web applications has received increased attentions at present. Many attacks work on real time and mostly prevention mechanisms focus on prevention and detection of these attacks on the web applications. This research focuses on giving attention to the top 10 threats that organizations need to know and to ensure the web applications are protected from these risks and attacks.

Status of weak scale supersymmetry after LHC Run 2 and ton-scale noble liquid WIMP searches

While LHC has discovered a very Standard Model-like Higgs boson of mass m_h~ 125 GeV, no solid signal for physics beyond the Standard Model has emerged so far at LHC or at WIMP seach experiments. For the case of weak scale supersymmetry (SUSY), LHC has found rather generally that gluinos are beyond about 2.2 TeV whilst top squark must lie beyond 1.1 TeV. These limits contradict older simplistic notions of naturalness that emerged in the 1980s-1990s, leading to the rather pessimistic view that SUSY is now excluded except for perhaps some remaining narrow corners of parameter space. Yet, this picture ignores several important developments in SUSY/string theory that emerged in the 21st century: 1. the emergence of the string theory landscape and its solution to the cosmological constant problem, 2. a more nuanced view of naturalness including the notion of "stringy naturalness", 3. the emergence of anomaly-free discrete R-symmetries and their connection to R-parity, Peccei-Quinn symmetry, the SUSY mu problem and proton decay and 4. the importance of including a solution to the strong CP problem. Rather general considerations from the string theory landscape favor large values of soft terms, subject to the vacuum selection criteria that electroweak symmetry is properly broken (no CCB minima) and the resulting magnitude of the weak scale is not too far from our measured value. Then stringy naturalness predicts a Higgs mass m_h~ 125 GeV whilst sparticle masses are typically lifted beyond present LHC bounds. In light of these refinements in theory perspective confronted by LHC and dark matter search results, we review the most likely LHC, ILC and dark matter signatures that are expected to arise from weak scale SUSY as we understand it today.

Application of Tiling Theory for Path Planning Strategy in a Polyiamond Inspired Reconfigurable Robot

Commercial floor cleaning robots face significant challenges in accessing convex and narrow corners due to their fixed and regular morphologies. To overcome this, we develop a new class of self-reconfigurable floor cleaning robot, hTetrakis, which is composed of tetriamonds (four equilateral triangles aligned along the edges) that adopt three distinct forms (“I”, “A”, and “U” shapes). When on a flat and rigid platform, these forms have convex corners that help to cover narrow regions. This paper addresses the mechanical structural design, reconfiguration of the robot platform through the hinge mechanism, and the electronics and navigation module of hTetrakis. Based on finite element studies, we estimate the system’s natural frequency, stress, and deformation patterns developed in the structural components of the robot, and validate the proposed design to overcome structural failure and system resonance. In order to achieve maximum area coverage using the tetriamond forms, we formulate tiling theorems and apply them for path-planning techniques during the floor cleaning process. By using a robot prototype, we conduct experiments to validate the proposed tiling theorem based on the percentage of area coverage, and demonstrate that this platform is able to cover the floor area efficiently.

Geometry effect on electrokinetic flow and ionic conductance in pH-regulated nanochannels

Semi-analytical solutions are obtained for the electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties associated with long pH-regulated nanochannels of arbitrary but constant cross-sectional area. The effects of electric double layer overlap, multiple ionic species, and surface association/dissociation reactions are all taken into account, assuming low surface potentials. The method of analysis includes series solutions which the pertinent coefficients are obtained by applying the wall boundary conditions using either of the least-squares or point matching techniques. Although the procedure is general enough to be applied to almost any arbitrary cross section, nine nanogeometries including polygonal, trapezoidal, double-trapezoidal, rectangular, elliptical, semi-elliptical, isosceles triangular, rhombic, and isotropically etched profiles are selected for presentation. For the special case of an elliptic cross section, full analytical solutions are also obtained utilizing the Mathieu functions. We show that the geometrical configuration plays a key role in determination of the ionic conductance, surface charge density, electrical potential and velocity fields, and proton enhancement. In this respect, the net electric charge and convective ionic conductance are higher for channels of larger perimeter to area ratio, whereas the opposite is true for the average surface charge density and mean velocity; the geometry impact on the two latest ones, however, vanishes if the background salt concentration is high enough. Moreover, we demonstrate that considering a constant surface potential equal to the average charge-regulated potential provides sufficiently accurate results for smooth geometries such as an ellipse at medium-high aspect ratios but leads to significant errors for geometries having narrow corners such as a triangle.

Simulation of air gap formation in slab continuous casting mould

A coupled model for describing the air gap formation in a continuous casting mould was developed. In the model, the evolution of the shell and mould temperatures and the gap between them were predicted by a two-dimensional transient thermomechanical coupled finite element model, and the formation of the air gap was described by an interfacial heat transfer model. Based on these, the basic formation characteristics of the air gap in a slab mould during casting of peritectic steel and the influences of varying the casting conditions, such as casting speed, mould taper, molten steel superheat and mould flux solidification temperature on the air gap formation, were described. The results show that the air gap in the mould first forms in the shell corner and mainly concentrates in the regions of 0–20 mm and 0–10 mm from the wide and narrow face corners respectively under typical continuous casting conditions of peritectic steel. The air gap on the shell wide face grows continuously and increases in the low part of the mould, where it mainly forms in the range of 160–450 mm below the meniscus on the shell narrow face. Increasing casting speed reduces the air gap. Increasing mould taper promotes air gap formation on shell wide face but reduces it slightly on the narrow face. Higher steel pouring and mould flux solidifying temperatures result in a wider air gap formation on both the wide and narrow faces.

<p class="SP274468"><strong>Asterocheres siphunculus, a new species of Asterocheridae (Copepoda, Siphonostomatoida) associated with Eucidaris tribuloides (Lamarck, 1816) (Echinodermata, Echinoidea) in Brazil</strong></p>

Asterocheres Boeck, 1859 is the most speciose genus within the copepod family Asterocheridae Giesbrecht, 1899. Its main hosts are sponges, cnidarians, bryozoans, and echinoderms. Among the latter there are records of Asterocheres associations with some species of the echinoid genus Eucidaris Pomel, 1883. Despite the wide distribution of Eucidaris tribuloides (Lamarck, 1883) in the coastal waters of Brazil, no records exist as yet of any copepod associated with this species. Asterocheres siphunculus sp. nov. is described herein based on samples collected from E. tribuloides sampled from two different sites off the coast of Salvador city, Bahia state, in northeastern Brazil. The new species shares a 20-segmented antennule with 20 congeners, but differs from them by having a very short siphon that reaches the insertion of the maxilla, a very wide rostrum that occupies the entire area between the antennules, and a pedigerous somite 4 with pointed and narrow posterolateral corners and a concave posterior margin.

Generation of a Plastic Crystal Including Methane Rotator within Metal-Organic Cavity by Forcible Gas Adsorption

The structural determination of saturated adsorbed methane inside a metal-organic cavity by the forcible pressure swing adsorption method (ca. 13 MPa) through a gas-adsorption equilibrium state gives a methane inclusion crystal even at 298 K. The adsorbed methane molecules regularly locate in the pocket-like narrow corners of the necks of the 1-D channel without disorder. The thermal motion of the pseudo-spherical methane molecules seems to be effectively suppressed in its translation mode but allowed rotation. In cooling to 90 K, the crystal structure remained essentially unchanged while the thermal motion decreased, indicating that a lower temperature reduces the rotation of the adsorbed pseudo-spherical methane. The observed crystal structure could also be influenced by a reduction of the vibrational magnitude, and a phase transition from a static disordered structure to an ordered state might occur. The observed crystal state at a higher temperature should have a plastic crystal nature in terms of the randomness of the orientation of incorporated guests. The single-crystal adsorbent is effective for crystallographic observation of the thermal activated guest forced into regular alignment in the crystal lattice, which can be used as a model of the supercritical fluid.

The Central Group in the Gigantomachy of the Old Athena Temple on the Acropolis

Recent examination of the preserved sculpture from the Gigantomachy pediment of the Old Athena Temple on the Athenian Acropolis has shown that a frontal chariot team occupied the center. Two fragmentary horses belong to the team and, judging from what remains, they are a pole horse and a trace horse, thus proving that the team was a quadriga, not a biga. Stiihler suggested that Zeus stood in the chariot, but did not speculate upon the presence of a passenger. On the basis of the iconography established for this myth, with Zeus, Athena, and Herakles always fighting in close proximity, I suggest that Herakles was a passenger in the chariot. This interpretation would explain the hole in the right breast of the wounded giant further to the right as evidence of an arrow shot by the hero.* The Gigantomachy is one of the most important myths depicted in Greek art, especially in the sixth and fifth centuries B.C.' Representations begin soon after the Panathenaic Games in honor of Athena were reorganized, and several of the earliest illustrations appear on vases dedicated on the Acropolis.2 One of the most impressive examples was the sculpted Gigantomachy that filled one pediment of the Old Athena Temple, whose foundations are preserved between the Parthenon and the Erechtheion. Much of this pediment is lost, but four of the participants are complete enough that we may be fairly confident of where they appeared in the composition: Athena, who strides to right; a wounded giant, who has fallen backward; and two crawling giants, who filled the narrow corners.3 Many puzzles remain, however. Here I discuss the identity and composition of the central figures of the pediment. In 1972, Klaus Stihler suggested that a frontal chariot team originally dominated the center of the pediment, and also argued persuasively that the building and its sculpture should be dated to the last decade of the sixth century rather than the penultimate one.4 The basis for this iconographical idea was his recognition that two horse protomes, which at the time stood in the courtyard of the Acropolis Museum, should belong to the Old Athena Temple; they are now exhibited in the museum gallery along with the rest of the sculpture from this pediment.5 * I wish to thank M.A. Littauer for discussing the reconstruction drawing with me. The following abbreviations are used: Brouskari M. Brouskari, The Acropolis Museum. A Descriptive Catalog (Athens 1974). Knell H. Knell, Mythos und Polis. Bildprogramme griechischer Bauskulptur (Darmstadt 1990). Schrader H. Schrader, Die archaischen Marmorbildwerke der Acropolis (Frankfurt 1939). Stahler K. Stihler, Zur Rekonstruktion und Datierung des Gigantomachiegiebels von der Akropolis, Antike und Universalgeschichte. Festschrift Hans Erich Stier (Miinster 1972) 88-112. 1 For the most comprehensive treatment, cf. LIMC IV (1988) 191-270, esp. 1-21 and 104-388, s.v. Gigantes (E Vian with the collaboration of M.B. Moore). 2 The most important examples, all very fragmentary, are Akr. 2211 (LIMC IV [1988] 215, no. 104); Akr. 607 by Lydos (ABV 107.1; Beazley Addenda2 29); Akr. 2134 (LIMC IV, 216, no. 106); Akr. 1632 (LIMC IV, 216, no. 110). 3 For these, cf. Schrader 347-61, cat. nos. 464-67. 4 Stdihler 88-112, esp. 88-91 for the frontal chariot. In this reconstruction (pl. 1), the team is not filled out to include four horses, but Knell 41, fig. 56, accepting this reconstruction, gives a team of four, crediting Stahler. Knell, however, prefers the earlier dating of ca. 520, but does not give a compelling stylistic argument (41-42). His main reason for retaining the earlier date is to link the tyrant's family with the reorganizing of the Panathenaic Games and their association with the representation of the Gigantomachy, which was woven into the new peplos used to adorn the wooden cult statue of the goddess. H.A. Shapiro, however, in his review of Knell (Gnomon 65 [1993] 644-46, esp. 645), reminds us that the temple, without losing its Panathenaic connection, could also be viewed as a monument celebrating the new democracy of Cleisthenes. Elsewhere, Shapiro has opted for the later dating (Art and Cult under the Tyrants in Athens [Mainz 1989] 38). W.A.P Childs, in recent articles, also accepts the lower dating for the Old Athena Temple (The Date of the Old Temple of Athena on the Athenian Acropolis, in W.D.E. Coulson et al. eds., The Archaeology of Athens and Attica under the Democracy [Oxford 1994] 1-6 and Herodotos, Archaic Chronology, the Temple of Apollo at Delphi,JdI 108 [1993] 399-441, esp. 404-405). 5 The better preserved example is Akr. 6454; the other is Akr. 15244. The most detailed discussion of them is Schrader 242-44, cat. no. 321. The scale of these horses may, at first observation, appear to be too small to belong with this sculpture, but when they were complete they were

Flow measurements in rod bundle subchannels with varying rod-wall proximity

Abstract Detailed measurements of fully developed, turbulent, air flow through a five-rod sector of a 37-rod bundle have been conducted for the design geometry of the bundle, as well as for several cases with the central rod displaced towards the external tube wall and/or towards a neighboring rod, including cases with rod-wall and rod-rod contact. The wall shear stress on an outer rod reached minima at rod-wall and rod-rod gaps and maxima at open flow regions. The average and the minimum wall shear stresses decreased dramatically only for very small values of the rod-wall gap. Measurements of the mean velocity, Reynolds stresses and turbulent scales in the wall and inner subchannels are presented mostly as iso-contours. Isotachs bulged towards narrow gaps and corners, with the bulging becoming more pronounced as the rod-wall gap decreased. The local friction factor not only varied appreciably around the rod as the gap decreased, but also had values much larger than the average friction factor based on the subchannel bulk velocity, due to the variability of the local flow width.

Design considerations in corrosion prevention by electrodeposits and organic coatings

It is clear that for satisfactory service and resistance to corrosion, it is necessary not only to choose the right metal to be electrodeposited, and the right thickness of deposit, but also to ensure that the design of the basic article to be plated is such that a reasonably uniform deposit can be achieved without too much difficulty. The more complex the shape to be plated, the higher will be the cost, either because the total weight of metal over the whole article will have to be greater in order to provide the minimum thickness in the most difficult places, or because special plating jigs and anodes will be required to achieve a uniform deposit. The designer should therefore strive to avoid deep or narrow recesses, sharp edges and corners, sharp points, and generally complex shapes; he should aim to provide relatively simple shapes without sudden changes of contour or cross‐section, and generous radii on all corners and edges, both external and re‐entrant. Ideally, the worse the throwing power of the solution to be used for electroplating, the more simple should be the shape to be plated. Fig. 1 illustrates some of the points mentioned.

A unified velocity correlation for corner wall regions

Following a discussion of the limitations of the universal logarithmic law of the wall in corner wall regions, a unified velocity correlation is proposed which is of such a form that it reduces to a half-power or square-root velocity distribution near the zero-stress regions of corners and to the familiar log-law far enough from the corners. It is found that, except in the case of very narrow corners, the experimental data on a wide variety of corner-flow geometries contain extensive regions of half-power velocity distribution.

Integral Equation Formulation for the Solution of Magnetic Field Problems Part I. Dipole and Current Models

Integral equations are shown to offer definite advantages over conventional finite difference techniques for solving magnetic field problems. In Part I of this paper two models are presented to account for the presence of a ferromagnetic medium. In the first model the magnetic material is replaced by an equivalent dipole distribution which gives rise to an integral equation for the scalar potential. The model is limited to problems involving nonmagnetic current carrying conductors. The second model uses a current distribution to represent the magnetic material. Therefore, it is not subject to the restrictions of the dipole model. Numerical solution of the resulting integral equation in both models is discussed. The technique offers considerable flexibility in the choice of the mesh size and shape. Also, geometries involving narrow air gaps and/or sharp corners are easily accommodated.