Using a fuzzy inference system to control a pumped storage hydro plant

The paper discusses the development of a fuzzy inference system (FIS) based governor control for a pumped storage hydroelectric plant. The First Hydro Company's plant at Dinorwig in North Wales is the largest of its kind in Europe and is mainly used for frequency control of the UK electrical grid. In previous investigations, a detailed model of the plant was developed using MATLAB(R)/SIMULINK(R) and this is now being used to compare FIS governor operation with the proportional-integral-derivative (PID) controller currently used. The paper describes the development of an FIS governor, and shows that its response to a step increase in load is superior to the PID under certain conditions of load. The paper proceeds to discuss the implications of these results in view of the possible practical application of an FIS governor at the Dinorwig plant

Effects of Bulk Viscosity in Non-linear Bubble Dynamics

The non-linear bubble dynamics equations in a compressible liquid have been modified considering the effects of compressibility of both the liquid and the gas at the bubble interface. A new bubble boundary equation has been derived, which includes a new term resulted from the liquid bulk viscosity effects. The influence of this term has been numerically investigated considering the effects of water vapor and chemical reactions on the bubble evolution. The results clearly indicate that the new term has an important damping role at the collapse, so that its consideration decreases the amplitude of the bubble rebounds after the collapse. This damping feature is more remarkable for higher deriving pressures.Comment: 4 pages, 7 figure

Ionic and electronic properties of the topological insulator Bi2_2Te2_2Se investigated using β\beta-detected nuclear magnetic relaxation and resonance of 8^8Li

We report measurements on the high temperature ionic and low temperature electronic properties of the 3D topological insulator Bi$_2$Te$_2$Se using ion-implanted $^8$Li $\beta$-detected nuclear magnetic relaxation and resonance. With implantation energies in the range 5-28 keV, the probes penetrate beyond the expected range of the topological surface state, but are still within 250 nm of the surface. At temperatures above ~150 K, spin-lattice relaxation measurements reveal isolated $^8$Li$^{+}$ diffusion with an activation energy $E_{A} = 0.185(8)$ eV and attempt frequency $\tau_{0}^{-1} = 8(3) \times 10^{11}$ s$^{-1}$ for atomic site-to-site hopping. At lower temperature, we find a linear Korringa-like relaxation mechanism with a field dependent slope and intercept, which is accompanied by an anomalous field dependence to the resonance shift. We suggest that these may be related to a strong contribution from orbital currents or the magnetic freezeout of charge carriers in this heavily compensated semiconductor, but that conventional theories are unable to account for the extent of the field dependence. Conventional NMR of the stable host nuclei may help elucidate their origin.Comment: 17 pages, 12 figures, submitted to Phys. Rev.

Dynamics of filaments and membranes in a viscous fluid

Motivated by the motion of biopolymers and membranes in solution, this article presents a formulation of the equations of motion for curves and surfaces in a viscous fluid. We focus on geometrical aspects and simple variational methods for calculating internal stresses and forces, and we derive the full nonlinear equations of motion. In the case of membranes, we pay particular attention to the formulation of the equations of hydrodynamics on a curved, deforming surface. The formalism is illustrated by two simple case studies: (1) the twirling instability of straight elastic rod rotating in a viscous fluid, and (2) the pearling and buckling instabilities of a tubular liposome or polymersome.Comment: 26 pages, 12 figures, to be published in Reviews of Modern Physic

Groundwater resources assessment using numerical model : a case study in low-lying coastal area.

The impacts of climate change and human pressure in groundwater have been greatest threats facing small islands. This paper represents a case study of groundwater responses towards the climate change and human pressures in Manukan Island Malaysia. SEAWAT-2000 was used for the simulations of groundwater response in study area. Simulations of six scenarios representing climate change and human pressures showed changes in hydraulic heads and chloride concentrations. Reduction in pumping rate and an increase in recharge rate can alter the bad effects of overdrafts in Manukan Island. In general, reduction in pumping rate and an increase in recharge rate are capable to restore and protect the groundwater resources in Manukan Island. Thus, for groundwater management options in Manukan Island, scenario 2 is capable to lessen the seawater intrusion into the aquifer and sustain water resources on a long-term basis. The selection of scenario 6 is the preeminent option during wet season. The output of this study provides a foundation which can be used in other small islands of similar hydrogeological condition for the purpose of groundwater resources protection

Women DPR-RI Members and the Public Policy Making Process: the Amendment of the General Election Law

This Policy Research is WRI's research report as well as recommendation for the involvement of women DPR-RI members in policy making. This policy research is a means for WRI to deliver inputs from its findings so that gender equality and equity, in particular the 30% quota target of women in parliaments can be achieved. This Women Research Institute (WRI) study attempts to see how the current women DPR-RI members are involved in the process of policy making, particularly policies that accommodate the needs and interests of women (gender responsive policies). Through this study, WRI also seeks to analyse the effectiveness of the 30% quota policy for women parliament members

Homophily and Contagion Are Generically Confounded in Observational Social Network Studies

We consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual's covariates on their behavior or other measurable responses. We show that, generically, all of these are confounded with each other. Distinguishing them from one another requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular we demonstrate, with simple examples, that asymmetries in regression coefficients cannot identify causal effects, and that very simple models of imitation (a form of social contagion) can produce substantial correlations between an individual's enduring traits and their choices, even when there is no intrinsic affinity between them. We also suggest some possible constructive responses to these results.Comment: 27 pages, 9 figures. V2: Revised in response to referees. V3: Ditt

Subadventitial stenting around occluded stents: A bailout technique to recanalize in-stent chronic total occlusions

To evaluate the outcomes of subadventitial stenting (SS) around occluded stents for recanalizing in-stent chronic total occlusions (IS-CTOs).There is little evidence on the outcomes of SS for IS-CTO.We examined the outcomes of SS for IS-CTO PCI at 14 centers between July 2011 and June 2017, and compared them to historical controls recanalized using within-stent stenting (WSS). Target-vessel failure (TVF) on follow-up was the endpoint of this study, and was defined as a composite of cardiac death, target-vessel myocardial infarction, and target-vessel revascularization.During study period, 422 IS-CTO PCIs were performed, of which 32 (7.6%) were recanalized with SS, usually when conventional approaches failed. The most frequent CTO vessel was the right coronary artery (72%). Mean J-CTO score was 3.1 ± 0.9. SS was antegrade in 53%, and retrograde in 47%. Part of the occluded stent was crushed in 37%, while the whole stent was crushed in 63%. Intravascular imaging was used in 59%. One patient (3.1%) suffered tamponade. Angiographic follow-up was performed in 10/32 patients: stents were patent in six cases, one had mild neointimal hyperplasia, and three had severe restenosis at the SS site. Clinical follow-up was available for 29/32 patients for a mean of 388 ± 303 days. The 24-month incidence of TVF was 13.8%, which was similar to historical controls treated with WSS (19.5%, P = 0.49).SS is rarely performed, usually as last resort, to recanalize complex IS-CTOs. It is associated with favorable acute and mid-term outcomes, but given the small sample size of our study additional research is warranted