scholarly journals State-of-the-art of contactless energy transfer (CET) systems: design rules and applications

2014 ◽  
Vol 1 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Riccardo Trevisan ◽  
Alessandra Costanzo
Keyword(s):  
Energy Transfer ◽  
State Of The Art ◽  
Resonance Condition ◽  
Systems Design ◽  
Maximum Efficiency ◽  
Extensive Review ◽  
Design Rules ◽  
Figures Of Merit ◽  
Automatic Machinery ◽  
Main Operating

This paper is dedicated to the extensive review of state-of-the-art contactless energy transfer (CET) systems that are gaining increasing interest in the automatic machinery industries. We first introduce the circuit equivalent networks considered in the literature, and discuss the main operating principles. Possible circuital resonant solutions are also discussed together with the required compensating networks. Then we focus on the problem of transferring, at the maximum efficiency, high-power levels (of the order of 1 kW or higher), showing that highly coupled inductive links are needed, requiring to refrain from the resonance condition. These systems are usually referred to as CET systems, since the link distances are negligible with respect to the coils dimensions. The operating frequencies are of the order of tens to hundreds of kilohertz. The fundamental figures of merit are analytically defined and used to measure the actual limitations involved in this class of systems, including aspects related to realization feasibility with respect to voltages and currents limitations. Finally, state-of-the-art CET works are surveyed, and realistic applications for different operating frequencies are considered and critically compared.

scholarly journals Characterization and Design of Photovoltaic Solar Cells That Absorb Ultraviolet, Visible and Infrared Light

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 78
Author(s):  
Sara Bernardes ◽  
Ricardo A. Marques Lameirinhas ◽  
João Paulo N. Torres ◽  
Carlos A. F. Fernandes
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
State Of The Art ◽  
Infrared Light ◽  
Maximum Efficiency ◽  
Space Applications ◽  
Figures Of Merit ◽  
The World ◽  
Photovoltaic Solar Cells ◽  
Lattice Matched

The world is witnessing a tide of change in the photovoltaic industry like never before; we are far from the solar cells of ten years ago that only had 15–18% efficiency. More and more, multi-junction technologies seem to be the future for photovoltaics, with these technologies already hitting the mark of 30% under 1-sun. This work focuses especially on a state-of-the-art triple-junction solar cell, the GaInP/GaInAs/Ge lattice-matched, that is currently being used in most satellites and concentrator photovoltaic systems. The three subcells are first analyzed individually and then the whole cell is put together and simulated. The typical figures-of-merit are extracted; all the I−V curves obtained are presented, along with the external quantum efficiencies. A study on how temperature affects the cell was done, given its relevance when talking about space applications. An overall optimization of the cell is also elaborated; the cell’s thickness and doping are changed so that maximum efficiency can be reached. For a better understanding of how varying both these properties affect efficiency, graphic 3D plots were computed based on the obtained results. Considering this optimization, an improvement of 0.2343% on the cell’s efficiency is obtained.

scholarly journals State of the art in persuasive systems design

2015 ◽  
Vol Volume 4, Number 1, Special... (Special Issue...) ◽  
Author(s):  
Anthony Foulonneau ◽  
Gaëlle Calvary ◽  
Eric Villain
Keyword(s):  
State Of The Art ◽  
Systems Design ◽  
Grand Challenge ◽  
Nouvelles Technologies ◽  
Societal Challenges ◽  
Persuasive Technologies ◽  
International Audience ◽  
Persuasive Systems Design ◽  
Persuasive Systems ◽  
Systems Studies

International audience By their ability to change person's behaviors and attitudes, persuasive technologies appear as promising for overcoming societal challenges. They are based on theories and models from cognitive psychology and social psychology. The earlier works on persuasive technologies, by Fogg, identified many persuasive principles to influence user's behaviors and attitude, and thus useful for building persuasive systems. Studies on persuasive technologies also bring design methods, architectures, persuasive interfaces, and experimentation in numerous domains. The grand challenge is now to adapt persuasion to the complexity and versatility of each individual, thereby maximizing the persuasive effectiveness. We still have to build plastic persuasive technologies. Les technologies persuasives, par leur capacité à agir sur le comportement et les attitudes des individus, sont une piste prometteuse dans de nombreux domaines, comme pour le traitement des grands défis sociétaux (ex : santé, environnement, …) ou le marketing (ex : inciter l’adoption d’un service, …) qui se présentent à nous. Elles s’appuient sur des résultats obtenus en psychologie cognitive et sociale lors des dernières décennies. Les travaux sur la persuasion technologique, initiés par Fogg à la fin des années 90, ont permis d’identifier de nombreux principes de persuasion sur lesquels les nouvelles technologies peuvent s’appuyer pour influencer le comportement de leurs utilisateurs. Ces travaux ont aussi permis de mettre en œuvre des méthodes de conception, des interfaces persuasives et d’expérimenter la persuasion technologique dans des domaines variés. Le plus grand défi reste maintenant d’adapter la persuasion à la complexité et à la variabilité intra-individuelle et interindividuelle, à la versatilité de chaque individu pour optimiser l’efficacité persuasive. Il nous reste à construire des technologies persuasives plastiques.

A Historical Overview of Design Analyses and Experimental Observations of Ratcheting Phenomenon

2020 ◽  
Author(s):  
Jean Macedo ◽  
Stéphane Chapuliot ◽  
Jean-Michel Bergheau ◽  
Eric Feulvarch ◽  
Olivier Ancelet ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
State Of The Art ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Design Codes ◽  
Historical Overview ◽  
Design Rules ◽  
Current Article ◽  
The Difference ◽  
Design Analyses

Abstract In order to investigate the ratcheting behavior and to determine new design rules, some experimental tests were conducted in many countries in the last decades. In France, some tests were carried out under mechanical or thermal cyclic loading to examine this risk. The first section of the current article is addressed to the state of the art concerning the ratcheting effects. The difference between Local and Global Ratcheting is clarified. The second section is dedicated to the experimental observations of ratcheting. The following section describes the constitutive models which are able to simulate material/structural ratcheting responses. The models presented are Linear Kinematic, Armstrong-Frederick, Chaboche, Ohno-Wang and Chen-Jiao-Kim. Finally, the ratcheting rules in design codes are exposed. Both simple and complex rules are presented.

Progress in the development of segmented thermoelectric unicouples at the Jet Propulsion Laboratory

2000 ◽  
Vol 626 ◽  
Author(s):  
T. Caillat ◽  
J.-P. Fleurial ◽  
G. J. Snyder ◽  
A. Borshchevsky
Keyword(s):  
Contact Resistance ◽  
Thermoelectric Materials ◽  
State Of The Art ◽  
Jet Propulsion ◽  
Electrical Efficiency ◽  
Figures Of Merit ◽  
Novel Materials ◽  
Metallic Interconnects ◽  
Jet Propulsion Laboratory

ABSTRACTA new version of a segmented thermoelectric unicouple incorporating advanced thermoelectric materials with superior thermoelectric figures of merit has been recently proposed and is currently under development at the Jet Propulsion Laboratory (JPL). This advanced segmented thermoelectric unicouple includes a combination of state-of-the-art thermoelectric materials based on Bi2Te3 and novel materials developed at JPL. The segmented unicouple currently being developed is expected to operate between 300 and about 975K with a projected thermal to electrical efficiency of up to 15%. The segmentation can be adjusted to accommodate various hot-side temperatures depending on the specific application envisioned. Techniques and materials have been developed to bond the different thermoelectric segments together for the nand p-legs and low contact resistance bonds have been achieved. In order to experimentally determine the thermal to electrical efficiency of the unicouple, metallic interconnects must be developed for the hot side of the thermocouple to connect the n- and p-legs electrically. The latest results in the development of these interconnects are described in this paper. Efforts are also focusing on the fabrication of a unicouple specifically designed for thermal and electrical testing.

English for Business Communication

2012 ◽  
Vol 45 (4) ◽  
pp. 410-445 ◽  
Author(s):  
Vijay K. Bhatia ◽  
Stephen Bremner
Keyword(s):  
State Of The Art ◽  
Business Communication ◽  
Genre Theory ◽  
Professional Communication ◽  
Genre Analysis ◽  
Extensive Review ◽  
Business English ◽  
Business World ◽  
Design And Implementation ◽  
Gradual Shift

The concept of Business English has undergone some major shifts in the last few years because of a number of developments, such as advances in genre theory and the coming together of English for Business Purposes and Business Communication, inspired by the realization that there is a gap to be bridged between the academy and the globalized business world. Drawing on advances in the analysis of business discourses, especially in applied genre analysis, this state-of-the-art review revisits the frameworks currently used in English for Business Purposes and Business Communication (or, more generally, Professional Communication) to suggest an integration of the two approaches for the design of English for Business Communication (EBC) programmes. The study incorporates an extensive review of much of the relevant published work in all the three areas mentioned above to identify some of the main issues in EBC, and illustrates a gradual shift in the rationale for the design and implementation of EBC programmes.

Turbine Cooling Systems Design: Past, Present and Future

2009 ◽  
Author(s):  
James P. Downs ◽  
Kenneth K. Landis
Keyword(s):  
Research And Development ◽  
Film Cooling ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Systems Design ◽  
Maximum Temperature ◽  
Cooling Systems ◽  
Cooling Flows ◽  
Turbine Cooling

Over a half a century ago, the power and performance of the first gas turbine engines were constrained by material limits on operating temperature. In these machines, the combustor exit temperature could not exceed the capability of the materials used to construct the turbine. Eventually, cooling was introduced into turbine components to enable turbine power and efficiency to be increased. That revolutionary step enabled gas turbines to become competitive with other heat engines for business, particularly in the rapidly expanding aviation and electrical power generation sectors. Although the first cooled turbine components may be considered crude by present standards, the underlying foundation of internal convection cooling remains the backbone for cooled turbine components today. Since its introduction, many improvements and additions to the fundamental basis of turbine component cooling have been developed. The introduction of film cooling is a prominent example. With this past research and development, turbine cooling system designs have progressed to the point where they represent the norm, rather than the exception in today’s gas turbines. Further, the confidence and robustness of these systems has been elevated to the point where the working fluid temperatures can exceed the maximum temperature of the structural materials by wide margins. In this paper, from an engineering perspective, we explore some of the significant accomplishments that have led to the current state-of-the-art in turbine cooling systems design. These systems employ a delicate balance of structural material capabilities with advanced internal and film cooling and the use of thermal barrier coatings to satisfy the goals and objectives of specific applications. At the same time, it is widely recognized that the use of cooling flows in the turbine results in parasitic losses that reduce performance. To that end, we also consider some of the specific challenges that face cooling system designers to reduce cooling flows today. Based on the research and development that has been performed to date, we consider the current status of cooling technology relative to a theoretical peak. Finally, we explore some of the hurdles that must be overcome to effectively raise the bar and realize future advancement of the state-of-the-art. The goal is to measure and separate new technologies that are merely different from those that are superior to past designs. Clearly, the identification of risk and risk reduction will play an important role in the development of future turbine cooling systems.

scholarly journals RF Performance of Si/SiGe MODFETs: A Simulation Study

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 325-330
Author(s):  
S. Roy ◽  
A. Asenov ◽  
S. Babiker ◽  
J. R. Barker ◽  
S. P. Beaumont
Keyword(s):  
State Of The Art ◽  
Strong Dependence ◽  
Intrinsic Noise ◽  
Performance Potential ◽  
Figures Of Merit ◽  
Analysis Technique ◽  
Channel Velocity ◽  
The Difference ◽  
Rf Performance ◽  
Gate Region

The microwave performance potential of Si/SiGe pseudomorphic MODFETs are studied, in comparison to state of the art InGaAs pseudomorphic HEMTs. Both devices have equivalent structures corresponding to a physical HEMT used for calibration. We use an RF analysis technique based on transient Monte Carlo simulations to estimate the intrinsic noise figures, the RF figures of merit fT and fmax, and the effect of contact and gate resistances. Both devices exhibit velocity overshoot below the gate region. It is shown that the difference in noise figures and fT values can be mainly attributed to differences in device channel velocity, fmax exhibits a strong dependence on device contact resistance, eroding some of the performance advantage of the pseudomorphic HEMT.

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