Energetic Macroscopic Representation (EMR).

Top PDF Energetic Macroscopic Representation (EMR).:

Modelling and Control of an Effort Feedback Actuator in Helicopter Flight Control Using Energetic Macroscopic Representation

Modelling and Control of an Effort Feedback Actuator in Helicopter Flight Control Using Energetic Macroscopic Representation

In helicopter field, electromechanical devices controllers are usually designed and tuned from global analysis with transfer functions calculations. This leads to control architectures with a reduced number of controllers. Their regulating loops are usually global PID controllers where parameters are directly set up on dedicated test benches. Energetic representation tools such as Energetic Macroscopic Representation (EMR) aim at simplifying systems analysis and control providing model and control structuring method. In this paper, a simplified helicopter flight axis control is modelled with the intention of controlling the helicopter stick force feedback. Performances of both global PID and energetic model based inversion controllers are discussed through simulation results.
En savoir plus

8 En savoir plus

Modeling and Control of the Modular Multilevel Converter connected to an inductive DC source using Energetic Macroscopic Representation

Modeling and Control of the Modular Multilevel Converter connected to an inductive DC source using Energetic Macroscopic Representation

The use of DC transmission is particularly advantageous for long-distance transmission and interconnection of asynchronous AC networks. Several converter topologies can be used for HVDC. Multilevel Modular Converters (MMCs) are the most favored given their technological advantages over other converters topologies. Due to their industrial maturity, they have become essential for all AC / DC conversion. So far, they have always been studied with a voltage source on DC side. However, when the converter is equipped with DC breaker, a series inductor is associated to limit current variations. This has consequences in term of modeling and control determination. This article aims to propose a modification of the control law in order to take into account this inductor. To facilitate the control organization, the Energetic Macroscopic Representation (EMR) is used.
En savoir plus

11 En savoir plus

Modelling and Control of an Effort Feedback Actuator in Helicopter Flight Control Using Energetic Macroscopic Representation

Modelling and Control of an Effort Feedback Actuator in Helicopter Flight Control Using Energetic Macroscopic Representation

In helicopter field, electromechanical devices controllers are usually designed and tuned from global analysis with transfer functions calculations. This leads to control architectures with a reduced number of controllers. Their regulating loops are usually global PID controllers where parameters are directly set up on dedicated test benches. Energetic representation tools such as Energetic Macroscopic Representation (EMR) aim at simplifying systems analysis and control providing model and control structuring method. In this paper, a simplified helicopter flight axis control is modelled with the intention of controlling the helicopter stick force feedback. Performances of both global PID and energetic model based inversion controllers are discussed through simulation results.
En savoir plus

2 En savoir plus

Energetic Macroscopic Representati on and Inversion Based Control  of a Modular Multilevel Converter.

Energetic Macroscopic Representati on and Inversion Based Control of a Modular Multilevel Converter.

The use of Energetic Macroscopic Representation (EMR) permits the modeling of the MMC and highlights the important couplings which exist between the different parts of the system. The inversion of the model leads to a general architecture of the control which cope with all these couplings. The control architecture leads to have as many controllers as state variables in the system which thus increases the robustness of the system. All the state variables are under control, which ensures all the dynamic of the system.

11 En savoir plus

Party Preference Representation

Party Preference Representation

Abstract Political parties are key actors in electoral democracies: they organize the legislature, form governments, and citizens choose their representatives by voting for them. How citizens evaluate political parties and how well the parties that citizens evaluate positively perform thus provide useful tools to estimate the quality of representation from the individual’s perspective. We propose a measure that can be used to assess party preference representation at both the individual and aggregate levels, both in government and in parliament. We calculate the measure for over 160,000 survey respondents following 111 legislative elections held in 38 countries. We find little evidence that the party preferences of different socio-economic groups are systematically over or underrepresented. However, we show that citizens on the right tend to have higher representation scores than their left-wing counterparts. We also find that whereas proportional systems do not produce higher levels of representation on average, they reduce variance in representation across citizens.
En savoir plus

41 En savoir plus

New coordination complexes-based gas-generating energetic composites

New coordination complexes-based gas-generating energetic composites

By varying the mass of nanothermite incorporated into the CuC, this study seeks to experimentally find the optimized Al/CuO to CuC mass ratio allowing: (i) the lowering of the power density budget for initiation, (ii) the self-sustained and total decomposi- tion of CuC to maximize the pressure peak, (iii) providing funda- mental understanding on the interplay of the two materials. We will discuss the combustion events in such CuC/Al/CuO energetic composites, experimentally evidenced thanks to coupled thermo- chemical analyses using calorimetry coupled with time-resolved mass spectrometry. Overall, we believe this work opens new per- spectives in the field of non-toxic gas generating material for micro and mini-airbag applications since this new energetic composites feature peak pressure of 12 MPa/g per cm 3 , which is 3.3 higher than that of traditional Al/CuO nanothermites, with much longer high-pressure durations ( ∼30 ms), and with the production of safe gases only .
En savoir plus

11 En savoir plus

Data representation synthesis

Data representation synthesis

Synthesizing Data Representations The problem of automatic data structure selection was explored in SETL [5, 24, 27] and has also been pursued for Java collection implementations [28]. The SETL representation sublanguage [9] maps abstract SETL set and map objects to implementations, although the details are quite dif- ferent from our work. Unlike SETL, we handle relations of arbi- trary arity, using functional dependencies to enforce complex shar- ing invariants. In SETL, set representations are dynamically em- bedded into carrier sets under the control of the runtime system, while by contrast our compiler synthesizes low-level representa- tions for a specific decomposition with no runtime overhead.
En savoir plus

13 En savoir plus

Antescofo Intermediate Representation

Antescofo Intermediate Representation

Research Report n° 8520 — April 2014 — 12 pages Abstract: We describe an intermediate language designed as a medium-level internal represen- tation of programs of the interactive music system Antescofo. This representation is independent both of the Antescofo source language and of the architecture of the execution platform. It is used in tasks such as verification of timings, model-based conformance testing, static control-flow analysis or simulation.

16 En savoir plus

Consciousness and representation

Consciousness and representation

This raises a major difficulty for the self-representational reading. For the idea of a unique mental act with two objects is very problematic if the primary and secondary relations are representations. Suppose that self-representational readers are right and that every mental act includes within itself, say, two partial representations — a primary and a secondary intentions. For example, you represent both the color and your representation of the color at the same time. Thus, the two objects of your total representation are a physical phenomenon and a mental phenomenon. The actual picture, however, is a bit more complex. It is well-known that, in Brentano’s view, “every mental phenomenon includes something as object within itself” (Brentano 1973: 125; Engl. trans. 88). Therefore, the objects of the total representation are, more precisely, the color and your act of seeing with its content — that is, your act of seeing qua something of which the color is a part. In other words: you represent the color and the act of seeing along with its content, namely the color. As a result, the color must be represented twice.
En savoir plus

15 En savoir plus

Ion transport in macroscopic RF linear traps

Ion transport in macroscopic RF linear traps

In many experimental situations, speed of operation can be an issue. We are interested in frequency metrology issues for larger clouds of trapped ions similar to [10, 11], and to that purpose, we have recently build a multi-trap system combining two macroscopic linear traps : one of quadrupole and one of octupole geometry [12]. Our objective is to study ion dynamics for various potentials, and the device relies on shuttling ions along a common z-axis. In the case described below, adiabatic transport of the sample would require transfer times of several tens of seconds, which is at least an order of magnitude longer than the interrogation times, and constitutes a dead time in the overall experiment, which we would like to reduce.
En savoir plus

20 En savoir plus

New coordination complexes-based gas-generating energetic composites

New coordination complexes-based gas-generating energetic composites

Reaction products and residues from burn rate tests of all CuC/Al/CuO energetic composites were collected and examined by SEM. As shown in Figure 4, giving analysis for Al/CuO, CuC/Al/CuO_75 and CuC/Al/CuO_50 samples, there are mainly two populations of product particle sizes, demonstrating the similar combustion behaviors between Al/CuO and CuC/Al/CuO composites. One has relatively larger dimension with a spherical shape and another with a dimension as small as ~50 nm but highly aggregated. EDS measurement results shown in supporting information Figure S5- S7 indicate that the larger ones are alumina particles with a coating of copper particles, and smaller ones are copper metal aggregates (might also contain cuprous oxide particles since oxygen signal was also found in these area).
En savoir plus

29 En savoir plus

The irreversible thermal expansion of an energetic material.

The irreversible thermal expansion of an energetic material.

The quasi-static thermomechanical behavior of both classes of energetic materials display common features, although their ductility is obviously reduced when the binder fraction decreases. At low stress triaxiality, such as uniaxial tension or compression, they undergo damage and strain softening (see Xu et al. (2008) ; Ellis et al. (2005) ; Le et al. (2010) , for instance), mainly by filler-binder debonding ( Rae et al. 2002 ), possibly by filler fracture ( Williamson et al. 2007 ; Trumel et al. 2010 ), until ultimate fracture at 10-150% elongation for solid propellants, 1-5% elongation for pressed explosives. At high stress triaxiality, such as triaxial compression, damage is partially inhibited, filler plasticity may be promoted, and ductility increases strongly with confining pressure ( Trumel et al. 2010 ; Wiegand et al. 2011 ). Additionally, binder-induced viscoelasticity is always displayed, even for very low binder fractions ( Drodge et al. 2010 ; Picart et al. 2010 ). Therefore, polymer-bonded energetic materials exhibit a continuum of thermomechanical behaviors when the binder fraction decreases, provided that the binder phase remains continuous, while direct grain-grain contact force chains must be considered if the binder phase is not continuous ( Bennett and Luscher 2019 ). Within this class of energetic materials, however, pressed explosives based on 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) display an additional peculiarity, namely irreversible thermal expansion. Under repeated thermal cycling, a progressive and irreversible increase of the specific volume, i.e. dilatancy, is observed, and tends, for a large number of cycles, to an asymptotic value dependent on the
En savoir plus

20 En savoir plus

Revealing extracellular electron transfer mediated parasitism: energetic considerations

Revealing extracellular electron transfer mediated parasitism: energetic considerations

www.nature.com/scientificreports/ of IET, such situation would correspond to a mutualistic interaction between electron-donating and accepting microorganisms. For instance, H 2 /formate-mediated EET is likely to be favourable for the growth of fermentative bacteria, as the standard potential for these compounds is −0.42 V vs SHE (25 °C, pH 7) 20 . In contrast, higher values of E RAP would be detrimental for the growth yield of the electron-accepting species at all values of α > 0 (see red lines in Fig.  3 ). This result clearly indicates that EET would disadvantage in most cases the growth of the fermentative partner, suggesting a kind of parasitic interaction in case of IET. An endergonic dissipation of the electrons in the three case studies (i.e. energetic parasitism, see Fig.  1 ) is also possible at E RAP values higher than −0.01 ± 0.09, + 0.46 ± 0.10 and + 0.55 ± 0.06 V vs SHE, respectively (see Fig.  3 ). In this particular case, the growth can be completely stopped at high α value, as the minimal catabolism is not able to compensate the energy losses related to EET. Glucose-fermenting bacteria would unlikely be able to uptake electrons at such high poten- tials (> + 0.46 V vs SHE) under anaerobic conditions. In contrast, in glycerol fermentation, all electrons uptaken by high potential RAPs (e.g. OmcF, ubiquinone) 20 , 22 would make the electron dissipation pathway endergonic with subsequent drastic decrease of growth yields.
En savoir plus

10 En savoir plus

Macroscopic Simulation of Deformation in Soft Microporous Composites

Macroscopic Simulation of Deformation in Soft Microporous Composites

Abstract Soft microporous materials exhibit properties, such as gated adsorption and breathing, which are highly desirable for many applications. These properties are largely studied for single crystals, however, many potential applications expect to construct structured or composite systems, examples of which include monoliths and mixed-matrix membranes. Herein, we use finite element methods to predict the macroscopic mechanical response of composite microporous materials. This implementation connects the microscopic treatment of crystalline structures to the response of a macroscopic sample. Our simulations reveal the bulk modulus of an embedded adsorbent within a composite is affected by the thickness and properties of the encapsulating layer. Subsequently, we employ this methodology to examine mixed-matrix membranes and materials of negative linear compressibility. This application of finite element methods allows for unprecedented insight into the mechanical properties of real-world systems and supports the development of composites containing mechanically anomalous porous materials.
En savoir plus

18 En savoir plus

Macroscopic modeling of colloids adsorption in porous media

Macroscopic modeling of colloids adsorption in porous media

A macroscopic model with a retardation factor, R, and an adsorption coefficient, K d , has been used to describe experimental data. The dependence of the retardation factor on both ionic strength (electrostatic interactions) and Peclet number (Hydrodynamics) has also been highlighted. Moreover, a non-dependence on medium length for same values of P e and I has been underlined.

3 En savoir plus

3D Macroscopic Architectures from Self‐Assembled MXene Hydrogels

3D Macroscopic Architectures from Self‐Assembled MXene Hydrogels

tial use of MXene-based materials in environmental cleanup because of their 3D macroscopic architectures. At room tem­ perature, adsorption capacities of 177, 169, 123, and 169 mg g- 1 for Pb(II), Cu(II), Zn(II), and Ni(II), respectively, could be achi e v e d . These results reveal that F-MXM has larger sorption capacities for many kinds of heavy metals compared to other heavy metal ion adsorbents (Table S3, Supporting Information). Because of the simplicity of the assembly of MXene, a high accessible surface area and the large number of active sites available in the 3D framework greatly improve the adsorption capacity for various heavy metal ions. In contrast, although the carbon foam had a high adsorption capacity for various classes of organic liquids, its adsorption capacity for heavy metal ions was very low as was the specific surface area. The absorption recyclability of F-MXM for phenoxin and Pb 2 + was tested and results are shown in Figure Sf . The process was repeated ten
En savoir plus

9 En savoir plus

Macroscopic models of collective motion and self-organization

Macroscopic models of collective motion and self-organization

We also assume that η ≪ 1 and we consider two scaling laws for η: (i) η = O(ε), (3.8) (ii) η = √ η 0 ε, with η 0 > 0, η 0 = O(1). (3.9) In the first scaling (3.8), the interaction range is of the same order as the interaction mean free path and is therefore microscopic. With the second assumption (3.9), the interaction range η = O( √ ε) is large compared to the interaction mean free path. It means that a particle interact with many more particles than just those that they are able to reach within an interaction time. In the macroscopic limit ε → 0, the interaction range shrinks to 0, meaning that it is smaller than a macroscopic quantity. Therefore, with the second scaling, the interaction range is intermediate between the microscopic scale and the macroscopic one. This choice of scales is illustrated in Fig. 3.
En savoir plus

27 En savoir plus

Macroscopic and edge behavior of a planar jellium

Macroscopic and edge behavior of a planar jellium

In particular, for a certain regime of temperature and total charge, the equilibrium measure is uniform on a disc as in the Ginibre ensemble, while the modulus of the farthest parti- cle[r]

18 En savoir plus

Constraints on energetic particles in the Fleischmann-Pons experiment

Constraints on energetic particles in the Fleischmann-Pons experiment

using scaling (Garcia et al. 1971) of other experimental cross sections. Results for the yield divided by the alpha energy are shown in Figure 4. As will be discussed, Pt K-alpha x-rays have been observed in Fleischmann-Pons experiments (Pt is often used as an anode, and Pt is usually found on the outer Pd cathode). Were these x-rays produced by energetic alpha particles, then one would expect more Pd K α x-rays than Pt K α x-rays, since the binding energy is less for Pd. We have plotted the ratio of the K-shell x-ray production cross sections for Pd relative to Pt in Figure 5. One sees that Pd K-shell x-rays would be produced much more efficiently by energetic alphas in the MeV range.
En savoir plus

26 En savoir plus

A Trace Macroscopic Description based on Time Aggregation

A Trace Macroscopic Description based on Time Aggregation

3.2.1 Visual Representation The macroscopic description we obtain has a reduced complexity, but space dimension is totally preserved. According to space complexity, it can be very difficult to represent the whole set of variables on a visualization without creating visual clutter. That is why we represent only the aggregated intervals, without their contents. The representation is a simple time line, and we associate aggregates to colored rectangles in which width is the duration. Each consecutive rectangle has a different color. The worst case complexity is n rectangles, where n is chosen small enough, less than 1000 elements, to be able to represent all the timeslices on a single computer screen. To summarize the meaning of our representation: we cut the trace in parts, and each part is considered to have a homogeneous behavior. This homogeneity is determined by the combined behavior of all the resources. In other words, all the resources have to behave in a homogeneous way to enable an aggregation of the whole time part.
En savoir plus

26 En savoir plus

Show all 985 documents...