Modeling of Small-Scale Wind Power System with Virtual Synchronous Generator

Wind power systems are the most commonly used systems for a renewable energy source over the past few decades. Most of the current wind turbines are large scale wind turbines which produce mega watts power. This thesis is prepared to develop a small scale wind turbine with axial flux permanent magnet synchronous generator for regional areas and small commercial industries. This thesis mainly focuses on the Axial Flux PMSG which is a small scale prototype with the characteristics of the large scale wind turbine generator and having a super capacitor embedded in it. The first objective is to create the dynamic wind gust model. The second objective is to study the background of the large scale wind turbine synchronous generator characteristics and to derive the equations to model the AFPMSG. The next objective is to implement the super capacitor model with a controller. The other main objective of this thesis is to design a Virtual Synchronous Generator to emulate the inertia and damping same as the conventional synchronous generator to maintain output power and the frequency stable when there is a change in the load. The model will be tested using the MATLAB-Simulink environment and the results will be discussed

Shrinking into the big city: influence of genetic and environmental factors on urban dragon lizard morphology and performance capacity

Urban wildlife faces a novel set of challenges resulting in selective pressure that can lead to population-level changes. We studied Australian water dragons (Intellagama lesueurii) from urban and natural populations to test if urban populations differed in body size, shape, and performance capacity. If urban-derived morphology has arisen through selection, we predicted distinct morphological differences between wild dragons from urban and natural areas in both adult and hatchling life-stages. Urban hatchlings were morphologically distinct (shorter body lengths and longer limbs) from natural populations, while urban adult males continued this trend but only for body size (shorter body lengths). We then experimentally reared hatchlings originating from urban and natural populations within urban- and natural-style enclosures (2 x 2 factorial design) for a year to determine if differences in morphology and performance capacity (sprint speed, endurance, and clinging ability) were related to either the individual's origin population or developmental environment. Yearlings reared in urban-style enclosures, irrespective of population origin, had smaller body sizes compared to those from natural-style enclosures, suggesting developmental environment was affecting their morphology. Despite this difference in body size, yearling dragon performance capacity was not significantly different between treatments. Overall, this study provides evidence of a complex relationship driving urban-divergent morphology - whereby urban dragons emerge as smaller hatchlings with longer limbs (innate traits) and are then further influenced by the urban environments that they develop in (phenotypic plasticity); however, and potentially owing to behavioral, ecological, and demographical differences, these changes appear to be sex-specific

Density waves in dry granular media falling through a vertical pipe

We report experimental measurements of density waves in granular materials flowing down in a capillary tube. The density wave regime occurs at intermediate flow rates between a low density free fall regime and a high compactness slower flow.Comment: LaTeX file, 17 pages, 6 EPS figures, Phys.Rev.E (Feb.1996

Pedestrian Solution of the Two-Dimensional Ising Model

The partition function of the two-dimensional Ising model with zero magnetic field on a square lattice with m x n sites wrapped on a torus is computed within the transfer matrix formalism in an explicit step-by-step approach inspired by Kaufman's work. However, working with two commuting representations of the complex rotation group SO(2n,C) helps us avoid a number of unnecessary complications. We find all eigenvalues of the transfer matrix and therefore the partition function in a straightforward way.Comment: 10 pages, 2 figures; eqs. (101) and (102) corrected, files for fig. 2 fixed, minor beautification

Parallelising and Developing Control Algorithms for Heterogeneous Architectures

System developers have found that exploiting parallel architectures for control systems is challenging and often, the resulting implementations do not provide the expected performance advantages over traditional uni-processor solutions. This paper presents a generic method and a suite of design tools for the implementation of control algorithms o parallel architectures.........

Heterogeneous and Homogeneous Parallel Architectures for Real-Time Adaptive Active Vibration Control

This paper presents an investigation into parallel processing techniques for real-time adaptive control of a flexible beam structure. Three different algorithms, namely simulation, control and identification are involved in the adaptive control algorithm. These are implemented on a number of computing platforms including a homogeneous network of transputer nodes, a homogeneous network of digital signal processing (DSP) devices, heterogeneous architectures involving transputers, reduced instruction set computer superscalar processor and DSP device, single DSP devices and transputer nodes and several general purpose sequential processors. The partitioning and mapping of the algorithms on the homogeneous and heterogeneous architectures is also explored. The inter-processor communication speed is investigated to establish the real-time performance aspects of the processors on the basis of the nature of the algorithms involved. A close investigation into the performance of several compilers is made and discussed within the context of real-time implementations. Finally, a comparison of the results of the implementations is made, on the basis of real-time communications performance, computation performance and complier performance, to lead to merits of design of parallel systems incorporating fast processing techniques for real-time control applications

Bethe ansatz solution of the Osp(1∣2n)Osp(1|2n) invariant spin chain

We have applied the analytical Bethe ansatz approach in order to solve the $Osp(1|2n)$ invariant magnet. By using the Bethe ansatz equations we have calculated the ground state energy and the low-lying dispersion relation. The finite size properties indicate that the model has a central charge $c=n$.Comment: 9 page

High-Temperature Hall Effect in Ga(1-x)Mn(x)As

The temperature dependence of the Hall coefficient of a series of ferromagnetic Ga(1-x)Mn(x)As samples is measured in the temperature range 80K < T < 500K. We model the Hall coefficient assuming a magnetic susceptibility given by the Curie-Weiss law, a spontaneous Hall coefficient proportional to rho_xx^2(T), and including a constant diamagnetic contribution in the susceptibility. For all low resistivity samples this model provides excellent fits to the measured data up to T=380K and allows extraction of the hole concentration (p). The calculated p are compared to alternative methods of determining hole densities in these materials: pulsed high magnetic field (up to 55 Tesla) technique at low temperatures (less than the Curie temperature), and electrochemical capacitance- voltage profiling. We find that the Anomalous Hall Effect (AHE) contribution to rho_xy is substantial even well above the Curie temperature. Measurements of the Hall effect in this temperature regime can be used as a testing ground for theoretical descriptions of transport in these materials. We find that our data are consistent with recently published theories of the AHE, but they are inconsistent with theoretical models previously used to describe the AHE in conventional magnetic materials.Comment: 6 pages, 5 figures, 1 table. Accepted to Phys.Rev.

Regional Conformational Flexibility Couples Substrate Specificity and Scissile Phosphate Diester Selectivity in Human Flap Endonuclease 1

Human flap endonuclease-1 (hFEN1) catalyzes the divalent metal ion-dependent removal of single-stranded DNA protrusions known as flaps during DNA replication and repair. Substrate selectivity involves passage of the 5′-terminus/flap through the arch and recognition of a single nucleotide 3′-flap by the α2–α3 loop. Using NMR spectroscopy, we show that the solution conformation of free and DNA-bound hFEN1 are consistent with crystal structures; however, parts of the arch region and α2–α3 loop are disordered without substrate. Disorder within the arch explains how 5′-flaps can pass under it. NMR and single-molecule FRET data show a shift in the conformational ensemble in the arch and loop region upon addition of DNA. Furthermore, the addition of divalent metal ions to the active site of the hFEN1–DNA substrate complex demonstrates that active site changes are propagated via DNA-mediated allostery to regions key to substrate differentiation. The hFEN1–DNA complex also shows evidence of millisecond timescale motions in the arch region that may be required for DNA to enter the active site. Thus, hFEN1 regional conformational flexibility spanning a range of dynamic timescales is crucial to reach the catalytically relevant ensemble

Singularites at a Dense Set of Temperature in Husimi Tree

We investigate complex temperature singularities of the three-site interacting Ising model on the Husimi tree in the presentce of magnetic field. We show that at certain magnetic field these singularities lie at a dense set and as a consequence the phase transition condensation take place.Comment: ps file, 10 page