Search results for " Inertia"
showing 10 items of 117 documents
Assessing the performance of thermal inertia and Hydrus models to estimate surface soil water content
2017
The knowledge of soil water content (SWC) dynamics in the upper soil layer is important for several hydrological processes. Due to the difficulty of assessing the spatial and temporal SWC dynamics in the field, some model-based approaches have been proposed during the last decade. The main objective of this work was to assess the performance of two approaches to estimate SWC in the upper soil layer under field conditions: the physically-based thermal inertia and the Hydrus model. Their validity was firstly assessed under controlled laboratory conditions. Thermal inertia was firstly validated in laboratory conditions using the transient line heat source (TLHS) method. Then, it was applied in…
Eckhaus instability of stationary patterns in hyperbolic reaction–diffusion models on large finite domains
2022
AbstractWe have theoretically investigated the phenomenon of Eckhaus instability of stationary patterns arising in hyperbolic reaction–diffusion models on large finite domains, in both supercritical and subcritical regime. Adopting multiple-scale weakly-nonlinear analysis, we have deduced the cubic and cubic–quintic real Ginzburg–Landau equations ruling the evolution of pattern amplitude close to criticality. Starting from these envelope equations, we have provided the explicit expressions of the most relevant dynamical features characterizing primary and secondary quantized branches of any order: stationary amplitude, existence and stability thresholds and linear growth rate. Particular em…
Online Estimation of the Mechanical Parameters of an Induction Machine Using Speed Loop characteristics and Recursive Least Square Technique
2022
This paper presents a novel approach for estimation of mechanical parameters, inertia and friction coefficient of an Induction Machine (IM) using speed loop characteristics and Recursive Least Square (RLS) estimator. Using the 5th order dynamic equation for Induction Machine and the forgetting factor based RLS algorithm the technique herein proposed employs the speed of the machine and the torque as the inputs for the estimator. Results obtained compares the estimated parameters with the actual parameters under multiple step varying and exponentially varying scenarios. Upon analyzing the results, the validity and the effectiveness of the proposed identification technique is confirmed
Mitigating-casi: relation between propositional content and discourse units
2018
El aproximativo casi entraña la inversión polar de su proposición, sin embargo, los usos considerados expletivos presentan valores atenuantes. Este trabajo complementa con un estudio de corpus la descripción teórica del uso expletivo-atenuante en relación con la unidad discursiva de casi en el habla coloquial. La unidad que ocupa en el discurso determina su uso atenuante y supone una prueba efectiva de su naturaleza semántica, al tiempo que aclara ciertas cuestiones de la bibliografía deductiva. This paper explores the mitigating function of Spanish casi and its relation to the discourse units casi fulfills in spoken language. Casi can either entail a polar inversion of the proposition it h…
Equilibrium geometries of cyclic SiC3 isomers
2001
Equilibrium geometries of two isomers of cyclic SiC3 are determined by both large scale ab initio calculation and a procedure involving the use of experimental data from microwave spectroscopy and calculated harmonic and cubic force fields. Internuclear distances corresponding to structures obtained by both procedures agree to better than 0.003 A in all cases, allowing for precise recommendations of equilibrium structures. Rather large residual inertial defects obtained from moments of inertia based on rotational constants adjusted for effects of vibration–rotation interaction were found to be reduced significantly by inclusion of electronic contributions as estimated from calculations of r…
Impact of RES penetration on the frequency dynamics of the 500 kV vietnamese power system
2019
The increase of renewable energy sources (RES) typically operating as converter-interfaced generation (CIG) is progressively causing a significant change of power systems operation paradigm. The reduction of the overall available kinetic energy and the consequent impact on the dynamic response of the system is a relevant issue currently under investigation in academic and industrial scopes. The work analyzes the impact of different CIG penetration in the three areas of the 500 kV Vietnamese power system, North, Center and South. The system is modified substituting conventional synchronous generation with converter-interfaced generation. The models of power converters and corresponding contr…
Inertial response of isolated power networks with wind power plants
2019
The constant increase of power generation provided by renewable energy source (RES) power plants is causing a progressive reduction of the overall inertia of the power systems. Especially in the case of small, isolated power networks, the replacement of conventional generation plants with RES power plants can affect significantly the frequency response of the system. The critical low-inertia conditions can be improved by the introduction of specific additional controls to the RES power converters. These control schemes are known as “synthetic inertia” or “virtual inertia” controls. The paper analyzes the impact of a derivative-based inertial control on a small, isolated power system, with a…
Primary Frequency Control in the Power System of Continental Europe including the Dynamics of the HVDC Link France-Great Britain
2020
The paper presents a study of primary frequency control within the power system of Continental Europe (CE) including the dynamics of the high voltage direct current (HVDC) link between France and Great Britain (GB). The large-scale dynamic model of the CE system originally provided by ENTSO-E is extended with a more detailed representation of the whole HVDC interconnection. The dynamics of the GB synchronous area is also considered in the analysis, implementing a system equivalent suitable for primary frequency control studies. The opportunity of frequency containment reserve exchange between the two areas through the link is also investigated, considering supplementary frequency controls w…
Critical questions in diabetes management: What are the most compelling challenges and how can we handle them?
2022
Background: The prevalence of diabetes mellitus is growing worldwide, showing almost a 10-fold increase in the last five decades. Despite advances in the understanding of the disease mechanisms, preventive measures, and treatment options, morbidity and mortality remain high. Moreover, the burden of uncontrolled glycemia and associated complications have a significant impact on healthcare costs. To be ready for the future and emerging issues in the management of diabetes and related disorders, a holistic approach is essential for the prevention of the next generations. So many challenges in the management of diabetes exist globally, which differ according to the health infrastructure, and cu…
Is experience a useful resource for business model innovation?
2016
ABSTRACTBusiness model innovation has been proposed as a powerful strategic tool, able to offer competitive advantage, create markets and even reshape industries. Despite these powerful effects, little research has been conducted into studying and improving business model generation methods, and even less study has gone into analysing how to define new business models that can exert a disruptive effect on markets and industries. Our work tries to fill this gap, analysing whether experience encourages or discourages the generation of disruptive business models. An empirical analysis was carried out using an experimental methodology. The results seem to contradict the currently dominant Resou…