A Characterization of Visibility Graphs for Pseudo-Polygons

In this paper, we give a characterization of the visibility graphs of pseudo-polygons. We first identify some key combinatorial properties of pseudo-polygons, and we then give a set of five necessary conditions based off our identified properties. We then prove that these necessary conditions are also sufficient via a reduction to a characterization of vertex-edge visibility graphs given by O'Rourke and Streinu

A mathematical model for the study of interstitial fluid movement vis-a-vis the non-newtonian behaviour of blood in a constricted artery

AbstractA mathematical model is developed with an aim to study the transport of interstitial fluid in the wall of a constricted artery by taking into account the microrotation of the erythrocytes of blood. The movement of the interstitial fluid has been described by the Debye-Brinkman equation. Exact solutions are obtained for the displacement of the solid matrix of the porous interstitial space, the velocity of the interstitial fluid movement, and the pressure distribution in the constricted arterial segment, for large and small consolidation times. Expression for the wall shear stress is also obtained for the constricted segment of the artery. Theoretical estimates of the distributions of the axial velocity of blood in the stenosed zone, rotational velocity of the erythrocytes, wall shear stress, and wall displacement, as well as the pressure and velocity profiles for the interstitial fluid movement, have been presented in the form of graphs

Histological and ultrastructural studies of the olfactory epithelium of spotted butter fish Scatophagus argus (Linnaeus)

The olfactory epithelium of Scatophagus argus (Linnaeus) was investigated by light and scanning electron microscopy. The elongated olfactory organ is made up of 20 to 22 primary lamellae arranged on both sides of the narrow median raphe. Sensory and non-sensory regions are located separately on each lamella. The sensory epithelium occupies the upper apical broad half and extreme basal part of the olfactory lamellae whereas the middle slender part is covered with non-sensory epithelium. The sensory epithelium consists of ciliated, microvillus, and crypt cells. The non-sensory epithelium is made up of stratified epithelial cells having different patterns of finger-like micro-ridges and mucous cells. Different cells lining the olfactory epithelium have been correlated with the functional views of the fish concerned. (Folia Morphol 2011; 70, 2: 74–79

Cellular organisation and functions of the olfactory epithelium of pearl spot Etroplus suratensis (Bloch): a light and scanning electron microscopic study

The cellular organisation of the olfactory rosettes of Etroplus suratensis was studied by light and scanning electron microscopy. The oval shaped olfactory rosette of the fish consists of 12 lamellae radiating from a central raphe. The olfactory lamellae are comprised of restricted areas of sensory epithelium and broad areas of non-sensory epithelium in the apical, middle, and basal regions. The sensory epithelium contains three types of receptor cells: microvillus, ciliated, and rod cells, as well as labyrinth cells and supporting cells. The non-sensory epithelium consists of stratified epithelial and mucous cells. The transitional region between the sensory and non-sensory epithelium consists of ciliated receptor cells, mucous cells, and stratified epithelial cells. The different cells on the olfactory epithelium were discussed regarding the functional significance of the fish concerned. (Folia Morphol 2010; 69, 3: 154-159

Synthesis of Corrosion-resistant Nanocrystalline Nickle-copper Alloy Coatings by Pulse-plating Technique

Bright and smooth nanocrystalline Monel-type Ni-Cu alloy gets deposited from complex citrate electrolyte by pulse electrolysis. Transmission electron microscopy studies have revealedthat the deposited Ni-Cu alloy was nanocrystalline in nature and it comprised a two-phase (fcc+Ll,) mixture. The presence of twins could be seen in the nanocrystals. The Ni-Cu alloysprepared by pulse electrolysis were finer grained (- 2.5-28.5 nm) than those deposited by direct current method. Nelson-Riley function has been used to calculate the lattice parameters for both the pulse current-plated and direct current-plated alloys from x-ray diffraction analysis. The microhardness values for pulse current-plated alloys were higher than for the direct currentplated alloys. The internal stresses of both the pulse current-deposited and the direct currentdeposited alloys have also been measured; the values were lower for pulse current-plated alloys. Potentiodynamic polarisation studies were carried out in aerated and deaerated neutral 3.0 Wt per cent NaCl solution and instantaneous corrosion current density of the plated alloy was determined and compared with the Monel-400 alloy. It was found that nanocrystalline pulse current-N,-35 8 Wt p;r cent copper alloy uxh~bitedlo wer instantaneous value of corros~onc urrent densirv than that of soeclrnens with direct current method and Monel-400 allov The d~ssolut~on ~ ~~~~-~ behaviour ofthe deposited nanocrystalline material was found to be more like general corrosion rather than localised corrosion as in the case of Monel-400 alloy

Loop antenna over a conducting cone with a spherical cap

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163889/1/mia2bf01314.pd

Coal mine fires - hazards and modern control techniques

Fires have long been recognized as hazards associated with coal mining. Coal mine fire causes economic losses by virtue of loss of coal and coal winning machinery. Environmental problems at surface and underground due to coal mine fire are discussed in terms of production of noxious, toxic gases, global warming and fire damp explosion. Social and health problems due to mine fire are dealt with. An account of modern techniques like water mist technology, remote sensing and infusion of carbon dioxide are also given

A comparative assessment of waste incinerators in the UK

The uptake in Europe of Energy from Waste (EfW) incinerator plants has increased rapidly in recent years. In the UK, 25 municipal waste incinerators with energy recovery are now in operation; however, their waste supply chains and business practices vary significantly. With over a hundred more plant developments being considered it is important to establish best business practices for ensuring efficient environmental and operational performance. By reviewing the 25 plants we identify four suitable case study plants to compare technologies (moving grate, fluidised bed and rotary kiln), plant economics and operations. Using data collected from annual reports and through interviews and site visits we provide recommendations for improving the supply chain for waste incinerators and highlight the current issues and challenges faced by the industry. We find that plants using moving grate have a high availability of 87-92%. However, compared to the fluidised bed and rotary kiln, quantities of bottom ash and emissions of hydrogen chloride and carbon monoxide are high. The uptake of integrated recycling practices, combined heat and power, and post incineration non-ferrous metal collections needs to be increased among EfW incinerators in the UK. We conclude that one of the major difficulties encountered by waste facilities is the appropriate selection of technology, capacity, site, waste suppliers and heat consumers. This study will be of particular value to EfW plant developers, government authorities and researchers working within the sector of waste management

Facets for Art Gallery Problems

The Art Gallery Problem (AGP) asks for placing a minimum number of stationary guards in a polygonal region P, such that all points in P are guarded. The problem is known to be NP-hard, and its inherent continuous structure (with both the set of points that need to be guarded and the set of points that can be used for guarding being uncountably infinite) makes it difficult to apply a straightforward formulation as an Integer Linear Program. We use an iterative primal-dual relaxation approach for solving AGP instances to optimality. At each stage, a pair of LP relaxations for a finite candidate subset of primal covering and dual packing constraints and variables is considered; these correspond to possible guard positions and points that are to be guarded. Particularly useful are cutting planes for eliminating fractional solutions. We identify two classes of facets, based on Edge Cover and Set Cover (SC) inequalities. Solving the separation problem for the latter is NP-complete, but exploiting the underlying geometric structure, we show that large subclasses of fractional SC solutions cannot occur for the AGP. This allows us to separate the relevant subset of facets in polynomial time. We also characterize all facets for finite AGP relaxations with coefficients in {0, 1, 2}. Finally, we demonstrate the practical usefulness of our approach. Our cutting plane technique yields a significant improvement in terms of speed and solution quality due to considerably reduced integrality gaps as compared to the approach by Kr\"oller et al.Comment: 29 pages, 18 figures, 1 tabl