Robust stability and performance analysis of unstable process with dead time using Mu synthesis

I. Thirunavukkarasu, V. George, G. Saravana Kumar  and A. Ramakalyan

The design of the H∞ Controller was done with µ synthesis for the unstable processes with dead time. It is important to look at various issues like disturbance rejection and the robustness of the controller due to the uncertainties present in the system. While designing the controller, the weighing functions are chosen such that the system could meet the performance requirements, such as the peak value of the µ plot should be less than one [1]. The D-K iteration is also used to improve the performance of the H-infinity controller. Once the D(s) is approximated, the plant is scaled appropriately and the H-infinity controller design is synthesized for the scaled plant. This procedure is repeated until; the µ calculation for robust performance yields a value less than 1 for all frequencies. The application of robust control was extended for such processes with uncertainties and disturbance as mentioned in [2, 3, 4, and 5].

Analysis on electrical energy consumption of agricultural sector in indian context

K. V. S. Ramachandra Murthy and M. Ramalinga Raju

This paper attempts to identify inter-linkages between agriculture and Electricity. The growth of agriculture has been possible because of timely and adequate supply of water. As a result, ground water irrigation started assuming greater importance as compared to canal irrigation. Farmers have better control over water availability with ground water irrigation. A study of Electrical Energy requirements for the irrigation purposes based on crop pattern and area irrigated under various heads has been carried out. The energy audit reports of various departments such as Irrigation, Agriculture and Electric Utilities are some time at variance. This paper highlights the need for proper interfacing between these agencies to evolve a credible strategy for optimum utilization of resources like electrical energy and underground water.

Steady state motion of rail vehicle with controlled creep forces on curved track

M. Messouci

A linear analysis of steady state curve traversing is developed for rail vehicle with wheels coupled with a torsional viscous damper. The governing equations are given and are solved numerically. We consider the equilibrium of the bogie with two wheel sets acted upon by the forces of gravity and the transverse force.The approach is based on providing guidance by creep forces in conjunction with wheel conicity, so that flange contact is normally avoided. It describes the behavior of the vehicle in the curves of different radii. It is therefore important to define the characteristics of the torsional damper. It gives the couple developed by the torsional damper as well as the bogie yaw, the relative lateral and yaw displacement of the leading and trailing wheel set at each curve track of constant curvature.

Dynamic compensation requirement analysis for an Indian utility

Anshul Chaudhary, Vivek C. Niraj, S. Prabhakar Karthikeyan, R. Nagaraja, I. J. Raglend and D. P. Kothari

This paper presents a technique to find out the suitable dynamic compensation requirement for an Indian utility i.e. Maharashtra region. The practical system considered was a part of western grid which is very critical for power evacuation from a major generating station. The objective of this paper was to increase the power flow in identified weak lines using dynamic compensation. As the variable capacitor does not suite economically, the option of using the series compensation which is used for reducing the angular separation and shunt compensation with (static VAR compensator) SVC was used for damping out the voltage oscillations at the receiving end is explored. The study result showed that the power flow could be increased considerably in the weak lines and also the system was stable in the steady state as well as in the dynamic conditions.

Computational modeling and simulation of low velocity impact on fibrous composite panels drop weight un_partitioned model

Umar Farooq and Kar Gregory

A computational model was developed to simulate and predict failure response of fibrous composite panels subjected to drop-weight impact on un-partitioned fibrous composite panels using finite element analysis. The mathematical formulation consisting of constitutive, equilibrium, and strain-displacement relations; finite element formulation with contact and external force; failure criteria proposed by Hasin. Finite Element Method (FEM) was chosen to perform simulation in commercially available software ABAQUS incorporating dynamic load in time-domain instead of using conventional analysis procedures of quasi-static indentation or drop weight model. To improve convergence, adaptive meshing techniques were employed to mesh the regions of high stress gradient with fine meshes and coarse meshes for the rest. Results were compared with the results from the available literature and found to be in good agreement. However, some values of acceleration parameters were very large. That was due to being computed from second order derivates, divided by very small time step size produced such larger values. Therefore, a four-point moving average filter was applied to remove ‘noise’ from the results. Some of the results from failure threshold loads were selected and included in the form of tables, contour plots and graphs.

Electrical energy loss in rural distribution feeders- A case study

K. V. S. Ramachandra Murthy and M. Ramalinga Raju

Abstract:

This paper presents the analysis of electrical energy loss in rural distribution feeders. Eastern Power Distribution Corporation Limited, APEPDCL of Andhra Pradesh State in India has been implementing some methods to reduce technical losses on rural distribution feeders. Statistical Data of two years on 80 rural distribution feeders of Visakhapatnam district has been analyzed and the results were presented. Field survey has been conducted to assess the exact conditions of feeder loading and distribution system configurations. The rural distribution feeders considered predominantly supply the agricultural loads.  Month wise cumulative percentage energy loss, power factor, length of line and line capacity were taken into consideration for analysis. Data of some sample feeders was presented. Critical observations were summarized. Suggestions were given for further improvement of efficiency of the system and reduction of losses based on simulation studies carried out.

Adjacent vertical members (columns and shear walls) in a tall building undergo differential time dependent deformations due to creep and shrinkage in concrete. These differential deformations in adjacent vertical members produce shear and moments in the connecting beams or slabs which further result in a redistribution of forces among vertical members. Shear walls in composite frame-shear wall systems are of concrete and properties of these will affect creep and shrinkage behaviour of these composite frame-shear wall systems. In this paper, behavioural studies are reported for these systems with varying shear wall properties. In these studies, the creep and shrinkage effects on deflections, differential deflections and axial forces in various members are evaluated. It is shown that significant change occurs in net change in elastic forces when volume to surface ratio is varied.

Abstract:

The digestive system is the one of the important system in the human body, which plays major role directly or indirectly for the normal function of human body. Most of the people around the world have the digestive system disorders due to improper digestion of food due to inefficient performance of stomach activity. The main objective of this paper is to propose a novel method of finding the digestive system disorders using Electrogastrogram [EGG], which is a non-invasive, cheap and painless method by detecting the electrical signal from the stomach cutaneously and also it acts as a preliminary investigation without a need for Endoscopy which is painful investigation. The recording setup explained in this proposed system includes LabVIEW software and hardware which is used to record the EGG for more than hundred patients, nearly 75% of the patients suffered from digestive system disorders, such as Dyspepsia, Stomach ulcer, nausea, cyclic vomiting syndrome, etc. For the above said digestive system disorders dissimilarity is found in its frequency and amplitude is compared with its normal individual parameter (3cpm) at a fair amount of accuracy.

Abstract:

Marble Powder is a waste product from marble cutting industries. It is produced in huge quantities and is a big environmental and health hazard. Therefore, researchers are focusing on development of technologies for its mass consumption. The present research aims to use marble powder in bulk quantities for manufacture of tiles. This paper presents results of an investigation on flexural strength and flexural creep characteristics of the flooring tiles containing marble powder. Four different mix proportions (1:5 to 1:8) were chosen for the investigation. The strength testing was carried out as per IS: 1237 and creep specimens were subjected to sustained central line load at 0.75 stress-strength ratio (applied stress: ultimate flexural strength) for a period up to 81 days. The change in deformation was found to become negligible between 45 to 60 days. The results indicated that the tiles satisfying flexural strength requirement as per IS: 1237 can be manufactured having marble powder content up to approximately 87%. These specimens also indicated that the creep deformations are lesser for tiles having greater proportions of marble powder.

Abstract:

Pavement rehabilitation and repair methods selection is one of the key issues many road organizations and researchers have occupied. Not only road management cost but also road user’s cost and cost for inhabitants and community should be included in the life cycle cost in order to help infrastructure investment judgment. Thus in estimating life cycle cost, Pavement rehabilitation and repair methods selection is essential even if technological capabilities of evaluation are not sufficient. In order for Pavement Management Systems (PMS) to be effective, they must be based on a reliable, statistically sound means for the rehabilitation and repair methods that are present on the system. To make sensible life cycle cost decisions in design and rehabilitation, pavement engineers must be able to account for distress phenomena and repair methods. This paper will present a Mathematical Failure-Theory (MFT) methodology for incorporating statistical and probabilistically Factors into life cycle cost analysis and PMS. This approach gives the engineer the ability to statistically and probability consider different rehabilitation and repair method and statistically and probability factors in computing the life cycle costs for rehabilitation and repair methods selection.

Abstract:

Telemedicine is the use of information technology to deliver medical services and information from one location to another. The evolution and growth of telemedicine is highly correlated with the developments in communication technology and IT software development. In Iraq health services was degraded not only in rural areas, but also, in the big cities because of the migration of doctors, especially, specialist doctors. There is a great shortage in the advance medical equipments so that there is a great need for telemedicine. This paper introduces two issues related to the telemedicine; the first issue is to introduce and discusses the possibilities of all available technologies that can be used to implement telemedicine facility in Iraq. Three scenarios of different levels and requirements were analyzed to cover the possible cases (big city, small town and mobile unit in a rural area). The second issue is to introduce the design and implementation of E-Hospitals to facilitate the process of medical data exchange.

Abstract:

Closed form analytical expressions for the displacement field due to single couples in a layer overlying a half-space using the Fourier Transform Method in term of Galerkin vector are obtained. In engineering, elastic layer represents an elastic plate while in geophysics it represents a lithosphere. This type of coupling of an elastic layer overlying an elastic half-space corresponds to the realistic earth model-lithosphere lying over an asthenoshere. These expressions are true for all Lame’s parameters to remain non-zero and non-infinite. The final results are simple and quite convenient.

Abstract:

Connecting green power sources to power grid are gradually becoming popular. Proper placement and sizing of these energy sources is important in order to obtain their maximum potential benefits. There have been studies to allocate the DG, in which loads are generally modeled as constant power or constant current types of loads. Since most of the distribution system loads are uncontrolled and dependent on the voltage and frequency of the system. Accordingly in this study a methodology has been presented that uses genetic algorithm to optimally place the DGs in terms of locations and sizes so as to minimize the per unit locational charges for active power at buses by incorporating different voltage dependent static load models. The presence of DG sources at distribution level has changed the characteristics of distribution network from passive to active. Nodal pricing and per unit locational charges often used in the pricing of short-term operation in transmission are good candidates to consider in distribution. Several simulation studies have been conducted on radial feeder as well as networked systems with single DG and multiple DG separately, subjected to no voltage violation at any of the buses.

Abstract:

Voltage instability in power systems is characterised by a monotonic voltage drop, which is slow at first and becomes abrupt after some time; and occurs when the system is unable to meet the increasing power demand. The operating conditions of the present day distribution systems are closer to the voltage stability boundaries due to the ever increasing load demand. Capacitors are used in distribution systems to minimise line losses and improve the voltage profile. A new algorithm for optimal locations and sizing of static and/or switched shunt capacitors, with a view to enhance voltage stability is presented in this paper. The superiority of this approach is demonstrated by testing the algorithm on 33 and 69-node distribution systems.