An algorithm for recognizing palm polygons

A polygonP is said to be apalm polygon if there exists a pointxP such that the Euclidean shortest path fromx to any pointyP makes only left turns or only right turns. The set of all such pointsx is called thepalm kernel. In this paper we propose an O(E) time algorithm for recognizing a palm polygonP, whereE is the size of the visibility graph ofP. The algorithm recognizes the given polygonP as a palm polygon by computing the palm kernel ofP. If the palm kernel is not empty,P is a palm polygon.The extended abstract of this paper was reported at the Second Canadian Conference in Computational Geometry, pp. 246–251, 1990     

Optimizing the energy and exergy of building integrated photovoltaic thermal (BIPVT) systems under cold climatic conditions

Building integrated photovoltaic thermal (BIPVT) system has the potential to become a major source of renewable energy in the urban environment. In this paper, the system has been used as the roof top of a building to generate higher electrical energy per unit area and to produce necessary thermal energy required for space heating. One-dimensional transient model has been developed using basic heat transfer equations. On the basis of this model, an analysis has been carried in order to select an appropriate BIPVT system suitable for the cold climatic conditions of India. The PV performances, net energy gain and exergy of the building are determined. The results show that for a constant mass flow rate of air the system connected in series gives a better performance whereas for a constant velocity of air flow the system connected in parallel gives a better performance. The BIPVT system, fitted on the rooftop in an effective area of 65 m², is capable of annually producing the net electrical and thermal exergies of 16,209 kW h and 1531 kW h, respectively, at an overall thermal efficiency of 53.7%.     

Influence of annealing on p-type Cu2ZnSnS4 thin film by dip coating solution growth technique for the application of solar cell

Thin films of Cu₂ZnSnS₄ have been deposited by solution growth dip coating method. Different Cu/Zn/Sn/S molar ratios were applied, which tells the properties of copper, Zinc, Tin, and Sulfide using X-ray diffraction, UV–vis, Energy dispersive X-ray spectroscopy, and scanning electron spectroscopy. The pure CZTS thin film showed the phase transformation from Kesterite (tetragonal) to Kesterite (orthorhombic) crystal structure. Optical measurement analysis reveals that layers have relatively high absorption coefficient in the visible spectrum with a band gap reduction of 1.51–1.49?eV with an increase in the annealing temperature from room temperature to 300?°C for 1?h in hot air furnace without any presence of an inert gas. Optical conductivity was observed to increase from 10¹² to 10¹³ (sec)^?1 and electrical conductivity was of the order of 10² (Ω?cm)^?1.     

Simple first-order translinear-C current-mode all-pass sections

A first-order translinear-C current-mode (CM) all-pass section (APS) using two current-controlled conveyors (CCCII) and a single capacitor is given. A canonical CM-APS using only one dual-output CCCII and one capacitor is also derived from the proposed configuration. The circuits are analysed for the non-idealities of CCCII and possess attractive sensitivity performance. The proposed circuits are electronically tunable over a wide frequency range. RSPICE simulation results for ac analysis, transient analysis and harmonic distortions are incorporated to verify the theory.     

Multi-objective optimization of electric-discharge machining process using controlled elitist NSGA-II

Parametric optimization of electric discharge machining (EDM) process is a multi-objective optimization task. In general, no single combination of input parameters can provide the best cutting speed and the best surface finish simultaneously. Genetic algorithm has been proven as one of the most popular multi-objective optimization techniques for the parametric optimization of EDM process. In this work, controlled elitist non-dominated sorting genetic algorithm has been used to optimize the process. Experiments have been carried out on die-sinking EDM by taking Inconel 718 as work piece and copper as tool electrode. Artificial neural network (ANN) with back propagation algorithm has been used to model EDM process. ANN has been trained with the experimental data set. Controlled elitist non-dominated sorting genetic algorithm has been employed in the trained network and a set of pareto-optimal solutions is obtained.

     

Energy-efficient production of chilled water in industry

Current practices for operation of a water-chilling plant (WCP) in the cement product industry in Kuwait have been studied and evaluated under different load conditions. Experimental results and weather data are used to demonstrate deficiencies in the present design. An analysis has been conducted to arrive at the optimum use of a cooling tower (CT) and chillers for year-round application. A significantly larger cooling tower is recommended for technical and economic viability. Our case study may serve as a guide for optimizing the design and operation of other types of water-chilling plants.     

Video--EEG monitoring in intractable attacks of uncertain etiology

Video-EEG monitoring was done in 26 patients with paroxysmal intractable attacks of uncertain etiology to determine the nature and cause. Two broad categories were identified: Those with prominent motor activity and those with attacks of collapse/limpness. Events were recorded in 16 patients of which 11 showed no abnormality on the simultaneously recorded EEG, thus helping to confirm their diagnosis of pseudoseizures.     

Effects of regulation on the flow regime of the river Murray,Australia

The flow regime of the River Murray has changed markedly over the last century, and especially the last 50 years, through increased diversions, construction of dams, weirs and levees and changes in operational procedures. A model developed by the Murray–Darling Basin Commission is used to compare simulated natural (unregulated) flows at eight stations with those at seven consecutive stages in the development of regulation. Monthly and annual average flows and coefficients of variation and skewness were computed, and the flow-duration, peak-flow and low-flow characteristics curves plotted. The results confirm that average monthly and annual flows are now considerably lower than those which prevailed under natural conditions. The seasonal distribution of flows has changed in the upper Murray, owing to the influence of dams. Flow-duration characteristics now vary considerably along the river, whereas there was little change under natural conditions. The effect of regulation on flow-duration characteristics is minimal at Albury and becomes more pronounced downstream; it is most apparent in regard to flows exceeded 20–80% of the time. The magnitude of average annual floods (annual exceedance probability 50%) has been reduced by over 50% at all stations, but big floods (average recurrence interval 20 years or more) are little affected. Further, the low flows for a given annual non-exceedance probability are higher under regulated conditions than those under natural conditions. These changes have profound implications for communities of native plants and animals in both riverine and floodplain environments, and also for the long-term utility of the river as a resource.