An application of frequency and duration approach in generationplanning

The available analytical tools for planning not only inadequately model pumped storage (PS) power plant units but also underestimate their load-levelling benefits. Therefore, if a PS power plant is among the candidate plants, its selection in the final “optimal plan” is highly unlikely. This research deals to assess the complete load-levelling benefits of PS units. The technique used is the frequency and duration approach coupled with the equivalent load duration curve (ELDC) method, used for generation planning. The proposed method is applied to IEEE RTS data and it is shown that almost 50% of PS benefits are not quantified in ELDC method     

Structured carbon haemoadsorbents for the removal of middle molecular weight toxins

There is continued interest in the development of novel haemoadsorbents for the removal of middle molecular weight molecules from blood in patients suffering with chronic renal failure. Conventional activated carbons have shown poor biocompatibility whereas polymer coated carbons have been applied with limited success. The external biocompatible coating significantly reduces the adsorption capacity for middle molecules due to size exclusion and slows down the adsorption kinetics due to mass transport limitations. In this work, we show that polymer derived mesoporous activated carbons (pore size in the range 2-50 nm) and surface area of between 400 and 800 m²/g are efficient adsorbents for middle molecular weight species such as interleukin IL-1beta.     

Integrated Urban Lei River (North Pakistan) Water Resources Management

The urban Lei river consists of a catchment area of about 211 km 2 . About 55% lies in Islamabad (population about 3 million) and the rest in Rawalpindi (population about 3 million). The city of Islamabad is growing without considering its hydrogeological set-up, which is creating further flood problems in Rawalpindi. Even after the drought of 1994, groundwater is being privately exploited without any central legal control. Measures for increasing the amount of available groundwater would improve drinking water both qualitatively and quantitatively, reduce loss through uncontrolled runoff, reduce aquifer depletion and lead also to improved monitoring. The chessboard regional city planning of Islamabad, as laid down in the Master Plan (1960), has to be replanned inter-disciplinary according to topographical, geological, meteorological, hydrological and hydrogeological investigations. Sustainable ecological solutions ought not be sacrificed to political short-sighted expedience.     

Possible Impact of Global Warming on Water Resources and Objects of Power Engineering

The main directions in global warming and its possible impact on the hydrological system are determined. __________ Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, May 2005, pp. 2 – 14.     

Exact memory size estimation for array computations

This paper presents a new algorithm for exact estimation of the minimum memory size required by programs dealing with array computations. Based on parametric partitioning of the iteration space and formalized live variable analysis, our algorithm transforms the minimum memory size estimation into an equivalent problem: integer point counting for intersection/union of mappings of parameterized polytopes. A heuristics was then proposed to solve the counting problem. Experimental results show that the algorithm achieves the exactness traditionally associated with totally unrolling loops while exploiting reduced computation complexity by preserving the original loop structure     

A synchronous generator fuzzy excitation controller optimallydesigned with a genetic algorithm

Design of a fuzzy logic power system controller with satisfactory performance is not an easy task. The difficulties come from two aspects. First, design of a fuzzy logic controller mainly uses the experience of the human experts. To acquire enough heuristic knowledge from the domain experts and to represent this kind of knowledge appropriately with a set of fuzzy rules present difficulties. Second, it is difficult to appropriately tune the parameters used in the fuzzy logic controller. These parameters are commonly determined by a “trial and error” method which is rather time consuming. In this paper, genetic algorithm is introduced to design an optimal fuzzy logic controller. The proposed method has been used to design an optimal fuzzy logic excitation controller for a generating unit. Test results with the fuzzy logic controller show very satisfactory results     

Comprehensive analysis of retroreflection in Papilio crino Fabricius, 1792 wings

Multilayer thin‐film structures in the wings of a butterfly; Papilio crino produce a colourful iridescence from reflected light. In this investigation, scanning electron microscope images show both the concave cover scales and pigmented air‐chamber ground scales. The microstructures with the concavities retroreflect incident light, thus causing the double reflection. This gives rise to both the colour mixing and polarisation conversion clearly depicted in the optical images. The result of the numerical and theoretical analysis via the CIELAB, and optical reflection and transmission of light through the multilayer stacks with the use of transfer method show that the emerging colouration on the Papilio crino is structural and is due to the combination of colours caused by multiple bounces within the concavities. The butterfly wing structure can be used as the template for designing the photonic device.Inspec keywords: bio‐optics, scanning electron microscopy, photodiodes, optical sensors, optical images, light reflection, reflectivity, colour, optical links, multilayers, optical multilayers, light polarisationOther keywords: pigmented air‐chamber ground scales, concavities, incident light, double reflection, colour mixing, polarisation conversion, optical images, numerical analysis, theoretical analysis, optical reflection, multilayer stacks, emerging colouration, butterfly wing structure, papilio crino fabricius, thin‐film structures, colourful iridescence, reflected light, electron microscope images, concave cover scales     

Amplitude comparator based algorithm for directional comparisonprotection of transmission lines

A high-speed directional comparison relay based on an evaluation of the locally measured deviations of the voltage and the phase-shifted current from their prefault values is described. The operation of the relay depends on the power frequency components of the voltage and phase-shifted current deviation signals. The direction to a fault is determined by an amplitude comparator technique which compares a discriminant value with a positive or negative threshold. Simulation studies on a three-phase power system model show that the direction to a fault is determined within the first few milliseconds following the inception of a fault. Studies over a wide range of faults and source impedance angles show that the proposed amplitude comparator technique performs better than an analogous phase comparator technique