Distinct Edge Research Articles

AN EXPERIMENTAL STUDY OF APPLYING VARIOUS CUTTING EDGES ON WIPER MILLING INSERTS IN FACE MILLING AISI 1070 STEEL

In metal cutting industry, edge preparation on carbide inserts have a significant effect on the productivity of a machine. In this study, the effect of various cutting edge preparations on wiper facet which influences various force components and surface finish in the rough milling operation of AISI 1070 steel were experimentally investigated. Tungsten Carbide inserts with three distinct edge preparations and AISI 1070 steel blocks were used. Three-factor (Cutting speed, Feed and Geometry), three-level full factorial design experiments were conducted under dry conditions. During the rough milling operation, three components of forces and surface finish of the machined surface were measured. This study shows that the effect of various edge geometries is more significant on surface finish and has very little impact on the force components.

Roadside habitats: effects on diversity and composition of plant, arthropod, and small mammal communities

Road edge effects cover extensive areas and exert a wide range of ecological influences on nearby plants and animals. Most studies have focused on individual and population level effects of the road edge; less is known about how communities and their functionality are altered in proximity to roads. Here, we studied the effect of road edges on species richness, rarity, endemism, composition, and functional (trophic) classification of communities of plants, ground-dwelling arthropods (beetles, spiders, scorpions, diplopods), and small mammals. The study, conducted in a Mediterranean ecosystem in central Israel, included sampling of these taxa in 10 plots adjacent to a regional road, and in 12 nearby control plots located in a typical shrubland habitat. We found a variety of community level road edge effects on the structure, composition, and function of the studied communities. The extent of effects varied among taxa, but they were generally positive or neutral. For the species-rich taxa (plants, beetles, and spiders), distinct road edge communities characterized by higher richness and altered species composition were found. Rarity and endemism were lower, and the proportion of disturbance-associated plant species was higher at the road edge. Among the species-poor taxa, scorpions and small mammals were more abundant along road edges than in control plots, while diplopods, the only negatively affected taxon, showed decreased abundance along the road. No ecologically meaningful changes in richness or composition were detected for the species-poor taxa along the road edge. Road edges profoundly affect floral and faunal communities, with possible implications for biodiversity conservation.

From Isolated Metaatoms to Photonic Metamaterials: Evolution of the Plasmonic Near-Field

Metamaterials are artificial media which can provide optical properties not available from natural materials. These properties often result from the resonant excitation of plasmonic modes in the metallic building blocks ("metaatoms") of the metamaterial. Electromagnetic interactions between the metaatoms significantly modify the resonances of the individual metaatoms and influence the optical properties of the whole metamaterial. To better understand these interactions, we study in this Letter the evolution of the plasmonic near-field in the course of the transition from an isolated metaatom, in our case a split-ring resonator (SRR), to a photonic metamaterial via electron energy-loss spectroscopy. For small SRR ensembles, we observe the formation of discrete optical bright and dark modes due to coupling of the metaatoms. Large SRR arrays reveal a quasi-continuum of modes in the interior and distinct edge modes at the boundaries of the array. Our experimental results are in excellent agreement with numerical calculations.

COMPARISON OF AGAR GEL IMMUNODIFFUSION TEST, IMMUNOHISTOCHEMSITRY AND REVERSE TRANSCRIPTION - POLYMERASE CHAIN REACTION FOR DETECTION OF INFECTIOUS BURSAL DISEASE VIRUS

The objective of this study was to compare agar gel immunodiffusion test (AGID) and immunohistochemistry (IHC) with reverse transcriptase-polymerase chain reaction (RT-PCR) in terms of sensitivity and specificity for the detection of infectious bursal disease virus (IBDV). Thirty-five bursal samples collected from filed outbreak of IBD were evaluated by all 3 diagnostic tests. Sensitivity and specificity of both AGIDT and IHC with RT-PCR was 94.12% and 100%, respectively. Both AGIDT and IHC showed a 94.29% association with RT-PCR with a k value of 0.482, indicating a moderate degree of agreement. The Cochran’s Q value was 4.00, which is lower than the critical value, indicating that the methods did not differ significantly (p>0.05) from each other in detection of samples as positive or negative. However, RT-PCR had distinct edge over these two tests employed in the study.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13452

The effect of rainstorms on adult Anopheles funestus behavior and survival

We describe the effect that the passage of a cold front, with a subsequent heavy rainstorm ten days later, had on a population of Anopheles funestus mosquitoes collected exiting houses or in light-traps from a village in southern Mozambique. Temperature effects explained 40% (r=0.634; p <0.001) of the variation in numbers of males collected and 19% of the variation in gravid females collected (r=0.437; p=0.033). The age structure of mosquitoes varied according to distance from the breeding site (χ(2) = 64.1, df 6, p <0.001). The proportion of parous insects that were caught in the light-traps with sacs (χ(2) = 6.33, d.f. 2, p=0.042) and young insects that had mated before being collected (χ(2) = 13,3, d.f. 2, p=0.001) were reduced on the night of the rain but this effect was short lived. It is concluded that the effect of rain on mosquito populations depends on the kind of water body used for larval development.

Polycyclic aromatic hydrocarbons as finite size models of graphene and graphene nanoribbons: Enhanced electron density edge effect

Distinct edge effects on physical and chemical properties are known to exist in graphene and graphene nanoribbons (GNRs). The present study provides a clue to understand the origin of these effects in terms of electron density distribution. Continuous electron density, molecular electrostatic potential and net charges obtained using density functional theory in several polycyclic aromatic hydrocarbons (PAHs) taken as finite size models of graphene and GNRs are analyzed. Electron density is found to be enhanced at the edges in comparison to those in the other parts of several PAHs and a similar distribution is also shown by spin densities in triplet ground states. Electron density is enhanced even at the hydrogen passivated internal edges created by removing carbon atoms of an inner benzene ring. Various experimental observations relating to distinct properties of edges of graphene and GNRs can be explained on the basis of the enhanced electron density edge effect.

A role of oxygen vacancy on annealed ZnO film in the hydrogen atmosphere

RF-sputtered ZnO films were annealed in the ambient atmospheres of Ar or hydrogen gas. Hydrogen effects on oxygen vacancies of ZnO films were studied through the characterizations of physical and electrical properties after annealing at 300 °C. The carrier concentration was increased to ∼1017 cm−3 in both annealing ambient atmospheres. On the other hand, the mobility was distinctly decreased when the films were annealed in the ambient atmosphere of Ar gas. Even though the physical structure undergoes small changes regardless of annealing ambient atmospheres, the increase of oxygen vacancies was remarkably suppressed in the annealing ambient atmosphere of hydrogen gas. Two distinct band edge states, generated by oxygen vacancies, are correlated to the changes in carrier concentration and mobility as a function of energy level below the conduction band.

Formation of One-Dimensional Electronic States along the Step Edges of CeO2(111)

Scanning tunneling microscopy (STM) combined with density functional theory (DFT) are used to analyze the structural and electronic properties of step edges on the surface of CeO(2)(111) films grown on Ru(0001). Depending on the preparation conditions, 211 or 110-oriented steps develop on the surface, which results in the formation of ceria ad-islands with hexagonal or triangular shapes. STM conductance spectroscopy reveals pronounced differences in the electronic properties of the step edges, as reflected in different onset positions of the ceria conduction band. The band shifts are related to the development of distinct edge electronic states that split-off from the ceria conduction band, as shown with DFT calculations. The separation of the edge states from the main band is governed by the atom-coordination and local charge-distribution along the edge, the latter giving rise to the development of electrostatic dipoles. We expect that the observed edge morphologies determine not only the electronic properties but also the adsorption behavior of step edges on the CeO(2)(111) surface.

Thermal Evolution of Band Edge States in ZnO Film as a Function of Annealing Ambient Atmosphere

RF-sputtered ZnO films were annealed under various annealing ambient atmospheres, including a vacuum, air, and water vapor. The physical and electrical properties of ZnO films annealed in various ambient atmospheres, were studied as a function of annealing temperature. The carrier concentration was dramatically increased, and the mobility was decreased when the films were annealed in a vacuum or water vapor. Even though the annealing ambient atmosphere and temperature were different, the preferred orientation and crystallization of the annealed ZnO films are maintained. However, two distinct band edge states below the conduction band, observed by spectroscopic ellipsometry measurement, undergo a thermal change as a function of annealing ambient atmosphere and these changes are correlated to changes in carrier concentration and mobility.

Dirac boundary condition at the reconstructed zigzag edge of graphene

Edge reconstruction modifies the electronic properties of finite graphene samples. We formulate a low-energy theory of the reconstructed zigzag edge by deriving the modified boundary condition to the Dirac equation. If the unit-cell size of the reconstructed edge is not a multiple of three with respect to the zigzag unit cell, valleys remain uncoupled and the edge reconstruction is accounted for by a single angular parameter $\ensuremath{\vartheta}$. Dispersive edge states exist generically, unless $|\ensuremath{\vartheta}|=\ensuremath{\pi}/2$. We compute $\ensuremath{\vartheta}$ from a microscopic model for the ``reczag'' reconstruction (conversion of two hexagons into a pentagon-heptagon pair), and show that it can be measured via the local density of states. In a magnetic field, there appear three distinct edge modes in the lowest Landau level, two of which are counterpropagating.

Prograph Based Analysis of Single Source Shortest Path Problem with Few Distinct Positive Lengths

In this paper we propose an experimental study model S3P2 of a fast fully dynamic programming algorithm design technique in finite directed graphs with few distinct nonnegative real edge weights. The Bellman-Ford’s approach for shortest path problems has come out in various implementations. In this paper the approach once again is re-investigated with adjacency matrix selection in associate least running time. The model tests proposed algorithm against arbitrarily but positive valued weighted digraphs introducing notion of Prograph that speeds up finding the shortest path over previous implementations. Our experiments have established abstract results with the intention that the proposed algorithm can consistently dominate other existing algorithms for Single Source Shortest Path Problems. A comparison study is also shown among Dijkstra’s algorithm, Bellman-Ford algorithm, and our algorithm.

Multiple-level defoliation assessment with hyperspectral data: integration of continuum-removed absorptions and red edges

Hyperspectral data were collected from 40 canopies of saltcedar (Tamarix ramosissima): 10 healthy canopies and 30 canopies defoliated by an introduced biological control agent, the saltcedar leaf beetle (Diorhabda carinata). These data assessed multiple-level defoliations in response to the process of biological control. Two important characteristics of the hyperspectral data – red edges and continuum-removed absorptions – were used to discriminate four defoliation categories of saltcedar (healthy plants, newly defoliated plants, completely defoliated plants and refoliating plants) at the canopy level. The red edge positions were located at ranges of 711–716 nm, 706–712 nm, 694–698 nm and 715–719 nm for the four defoliation stages described above, respectively. These red edge positions alone could not clearly judge the four defoliation categories associated with feeding by the beetles. Only the completely defoliated canopies had distinct red edge positions that could be differentiated from the other three types of canopies. While using a classification tree to integrate the red edge positions and their derivatives with the central band depths of these five continuum-removed absorptions, it was found that only two band depths of the continuum-removed absorptions were selected, which were the red absorption between 570 and 716 nm and the water absorption between 936 and 990 nm in the near-infrared region (NIR). This implied that the continuum-removed absorptions outperformed the red edges for identifying the defoliation categories. The resulting overall accuracy was 87.5%. The producer accuracy was 100%, 70%, 100% and 80% for the healthy plants, newly defoliated, completely defoliated plants and refoliating canopies, respectively. The corresponding user accuracy was 90.91%, 77.78%, 100% and 80%. Therefore, we concluded that single spectral data based variable failed to separate the four stages but a combination of the two continuum-removed absorptions located in the blue absorption and the first water absorption in the NIR improved the identification of defoliated canopies associated with the dynamic defoliation process of the biological control agent. This study developed the defoliation detection techniques of commonly used binary levels (i.e. defoliation and non-defoliation) to multiple vegetation defoliation levels. We anticipate applying these assessment techniques to wide-area collections of hyperspectral data covering the two spectral regions as described above to further evaluate the effectiveness of these biological control beetles and their impact on saltcedar management in the Western United States.

Defect states in epitaxial HfO2 films induced by atomic transport from n-GaAs (100) substrate

We investigated the chemical states and nature of the defect states below the conduction band edge of HfO2 films grown on GaAs (100) substrates using high-resolution x-ray photoelectron spectroscopy (HRXPS), x-ray absorption spectroscopy (XAS), and density functional theory calculations. O K1-edge absorption spectra of the HfO2/GaAs film revealed two distinct conduction band edge defect states, located at 1.6 ± 0.2 eV and 3.0 ± 0.2 eV below the conduction band edge in HfO2. The combined XAS and HRXPS results as a function of post-deposition annealing temperature indicated that the changes in defect states below the conduction band edge of HfO2 were correlated with the extent of interfacial chemical reactions between the HfO2 film and the GaAs substrate. Spectroscopic and theoretical results revealed that the two conduction band defect states are caused by (i) diffused Ga–O states, Hf3+ states, and (ii) an O divacancy related to the As–O states, respectively.

Clear-cutting affects habitat connectivity for a forest amphibian by decreasing permeability to juvenile movements

Conservation of forest amphibians is dependent on finding the right balance between management for timber production and meeting species' habitat requirements. For many pond-breeding amphibians, successful dispersal of the juvenile stage is essential for long-term population persistence. We investigated the influence of timber-harvesting practices on the movements of juvenile wood frogs (Lithobates sylvaticus). We used a chronosequence of stands produced by clear-cutting to evaluate how stand age affects habitat permeability to movements. We conducted experimental releases of juveniles in 2008 (n = 350) and 2009 (n = 528) in unidirectional runways in four treatments: mature forest, recent clearcut, 11-year-old, and 20-year-old regeneration. The runways were 50 x 2.5-m enclosures extending into each treatment, perpendicular to a distinct edge, with four tracking stations at 10, 20, 30, and 40 m from the edge. We recorded the number of animals reaching each tracking station, and the proportion of animals changing their direction of movement at each distance. We found that the mature forest was 3.1 and 3.7 times more permeable than the 11-year-old regeneration and the recent clearcut, respectively. Animals actively avoided open-canopy habitats and sharp edges; significantly more animals returned toward the closed-canopy forest at 0 m and 10 m in the less permeable treatments. There were no significant differences in habitat permeability between the mature forest and the 20-year-old regeneration. Our study is the first to directly assess habitat permeability to juvenile amphibian movement in relation to various forestry practices. We argue that habitat permeability at this scale is largely driven by the behavior of animals in relation to habitat disturbance and that caution needs to be used when using spatial modeling and expert-derived permeability values to assess connectivity of amphibian populations. The effects of clear-cutting on the migratory success of juvenile L. sylvaticus are long-lasting. Forestry practices that involve canopy removal and conversion of natural forest to conifer plantations may affect regional population viability by hindering successful dispersal.

Formation of Irregular Al Islands by Room-Temperature Deposition on NiAl(110)

ABSTRACTSTM studies reveal that irregular non-equilibrium two-dimensional Al islands form during deposition of Al on NiAl(110) at 300 K. These structures reflect the multiple adsorption sites and diffusion paths available for Al adatoms on the binary alloy surface, as well as the details of inhibited edge diffusion and detachment-attachment kinetics of Al adatoms for numerous distinct step edge configurations. We attempt to capture these features by multi-site lattice-gas modeling incorporating DFT energetics for adatoms both at adsorption sites and transition states. This formulation enables description and elucidation of the observed island growth shapes.

The influence of humic acid on the pH-dependent sorption of americium(III) onto kaolinite

This work investigates the sorption of ameri- cium (Am(III)) onto kaolinite and the influence of humic acid (HA) as a function of pH (3-11). It has been studied by batch experiments (V/m = 250:1 mL/g, CAm(III) = 1 9 10 -5 mol/L, CHA = 50 mg/L). Results showed that the Am(III) sorption onto the kaolinite in the absence of HA was typical, showing increases with pH and a distinct adsorption edge at pH 3-5. However in the presence of HA, Am sorption to kaolinite was significantly affected. HA was shown to enhance Am sorption in the acidic pH range (pH 3-4) due to the formation of additional binding sites for Am coming from HA adsorbed onto kaolinite surface, but reduce Am sorption in the intermediate and high pH above 6 due to the formation of aqueous Am- humate complexes. The results on the ternary interaction of kaolinite-Am-HA are compared with those on the binary system of kaolinite-HA and kaolinite-Am and adsorption mechanism with pH are discussed. Effect of different molecular weight of HA, with three HA fractions separated by ultrafiltration techniques, on the Am sorption to kao- linite were also studied. The results showed that the enhancement of the sorption of Am onto kaolinite at the acidic pH conditions (pH 3-4) was higher with HA frac- tions of higher molecular weight. Also, the Am sorption over a pH range from 6 to 10 decreased with decreasing molecular weight of HA.

Transient Separation Control Using Pulse-Combustion Actuation

The transitory response of the flow over a stalled, two-dimensional (NACA 4415) airfoil to pulsed actuation on time scales that are an order of magnitude shorter than the characteristic convective time scale is investigated experimentally (Re = 570, 000). Actuation is effected by momentary [O(1 ms)] pulsed jets that are generated by a spanwise array of combustion-based actuators integrated into the center section of the airfoil. The flowfield in the cross-stream plane above the airfoil and in its near wake is computed from multiple high-resolution particle image velocity images that are obtained phase locked to the actuation waveform and allow for tracking of vorticity concentrations. The brief actuation pulse leads to a remarkably strong transitory change in the circulation about the entire airfoil that is manifested by a severing of the separated vorticity layer and the subsequent shedding of a large-scale clockwise vortex that forms the separated flow domain. The clockwise severed vorticity layer that follows behind this detached vortex has a distinct sharp streamwise edge that grows and rolls up as the layer is advected along the surface. It is shown that the shedding of the severed vortex and the accumulation of surface vorticity are accompanied by a transitory increase in the magnitude of the circulation about the airfoil that lasts 8—10 convective time scales. The attached vorticity layer ultimately lifts off the surface in a manner that is reminiscent of dynamic stall, and the flow separates again.

Strategic outsourcing: status and prospects in global product development processes

Nowadays, firms are realising that being alone in the product development process does not provide them with any differentiation in their production lines and is causing the emergence of a widespread moving towards the phenomenon of outsourcing. The objectives of such an approach are not only cost-effectiveness and focusing on core competition, but also firms are adopting outsourcing to obtain a distinct marketing edge and to score over their competitors. In this paper, the overall strategic views of outsourcing in manufacturing industries are critically analysed and discussed together with the potentials and pitfalls of this emerging approach.

Robust self-assembly of graphs

Self-assembly is a process in which small building blocks interact autonomously to form larger structures. A recently studied model of self-assembly is the Accretive Graph Assembly Model whereby an edge-weighted graph is assembled one vertex at a time starting from a designated seed vertex. The weight of an edge specifies the magnitude of attraction (positive weight) or repulsion (negative weight) between adjacent vertices. It is feasible to add a vertex to the assembly if the total attraction minus repulsion of the already built neighbors exceeds a certain threshold, called the assembly temperature. This model naturally generalizes the extensively studied Tile Assembly Model. A natural question in graph self-assembly is to determine whether or not there exists a sequence of feasible vertex additions to realize the entire graph. However, even when it is feasible to realize the assembly, not much can be inferred about its likelihood of realization in practice due to the uncontrolled nature of the self-assembly process. Motivated by this, we introduce the robust self-assembly problem where the goal is to determine if every possible sequence of feasible vertex additions leads to the completion of the assembly. We show that the robust self-assembly problem is co-NP-complete even on planar graphs with two distinct edge weights. We then examine the tractability of the robust self-assembly problem on a natural subclass of planar graphs, namely grid graphs. We identify structural conditions that determine whether or not a grid graph can be robustly self-assembled, and give poly-time algorithms to determine this for several interesting cases of the problem. Finally, we also show that the problem of counting the number of feasible orderings that lead to the completion of an assembly is #P-complete.

Automatic detection of chessboard and its applications

A chessboard image can be used as a pattern for camera calibration and pose estimation. We propose an algorithm for the automatic detection of a chessboard using one circle as a probe. We first generate candidates using the Lucas-Kanade feature detector algorithm. Finally, we find control points on the chessboard using properties inherent on a chessboard pattern. We suggest that a distinct edge along the border line and black and white sequence on the chessboard can be used as constraints. A circle is used as a probe for checking those properties. We show that the proposed algorithm can be used successfully in camera calibration and pose estimation. Experimental results using images acquired under the variation of scale, pose, and illumination shows the robustness of proposed algorithm.