Search results for "efficiency."
showing 10 items of 1362 documents
Agro-food markets’ functional efficiency, products’ quality and information’s role
2018
Nowadays agro-food productions’ quality and markets’ economic efficiency are strictly connected and related to the increasing information’s role that is no doubt simplify by the global presence of the World Wide Web system. It is possible to assert that this kind of situation does not always safeguard information’s safety and propriety and at the same time consumers’ aware and complete choice capability. From a production markets’ economic efficiency point of view these elements contribute to create some kind of functional distortions able to prevent their proper working system under the economic theory profile and supply misunderstandings and informational asymmetries. These specific condi…
Effective simulation model and new control strategy to improve energy efficiency in hybrid electric land vehicle
2014
The main objectives of this work is to develop an effective modeling method for an easydeployment of a control strategy, to review and study an optimal control strategy for a specific application, and to analyze improvement that can be effected to engine for better efficiency in hybrid vehicle architecture. The scopes of this work include the simulation part of the studied system and its validation with experimental results. Study cases are used to analyze optimization that can be effected to the original system. A well established optimization tool is chosen to optimize the actual control strategy and becomes a benchmark of a new optimal control strategy to be deployed in the system. A pre…
Smart strategy of an hybrid vehicle global energetic system gestion
2018
The main objective of this work is to develop an optimal management strategy to improve energetic efficiency of hybrid electric vehicle. This work is composed by a mobility experimental analysis part, a numerical modelization part and an optimization part of the energy management strategy. The study of mobility allow to highligth and quantify the predictibility of trips, due to a constraint mobility.The dynamic modelling of the vehicle which is necesary to study perfomance of strategies, was realized by Energetic Macroscopic Representation (EMR) which is a good methode in this case. The proposed strategy is based on the predictive control (MPC), solve by a method of Programming Quadratic, a…
The Education Production Function reviewed in the framework of Education For All in Sub-Saharan Africa: from theoretical and methodological bounds to…
2007
The Coleman report (1966) was the first of numerous researches exploring quality of learning determinants analysis. With the Education Production Function (EPF), economists have greatly contributed to the extension of this research domain. Actually, empirical works are leading the field with important methodological debates which have fuelled controversies (Hanushek, 2003; Krueger, 2003). Thus, methodological issues have particularly rallied researchers' interests on empirical estimations, while academic researches on the renewal of the theoretical framework have remained scarce despite obvious bounds. Without contesting the validity of miscellaneous estimation problems and the necessity of…
Efficient energy conversion for cubic third-harmonic generation that is phase matched in KTiOPO(4).
2000
We demonstrate, for the first time to our knowledge, that efficient third-harmonic generation can be achieved with a cubic contribution much larger than the quadratic processes. An energy-conversion efficiency of 2.4% is achieved for cubic third-harmonic generation that is phase matched along the x axis of a KTiOPO(4) crystal by use of a picosecond fundamental laser emitting at 1618 nm. The associated cascading processes are only 10% of the pure cubic interaction, which is very suitable for study of the specific quantum optical correlations. Calculations of the third-harmonic generation conversion efficiency with respect to group-velocity dispersion and to the longitudinal Gaussian beam pro…
Assessment of MOSFET switching losses in an LLC converter by a calorimetric method
2023
The present work aims to implement a calorimetric method to measure the power dissipated during MOSFET switching in a high efficiency LLC resonant converter. The power dissipated from switching can significantly impact the total power dissipated by the device and consequent efficiency, so correct quantification is fundamental for optimizing the devices and increasing the efficiency of the converters. In LLC converters, this type of dissipated power cannot be measured with standard methods such as measurement with oscilloscopes as some of the energy that is recovered and not dissipated. The calorimetric method requires reasonably accurate measurement of thermal resistance and the temperature…
Hybrid Energy Storage for Underground Mining EV
2021
One of the main concerns when it comes to contributions to the carbon footprint is the consumption of fuel by vehicles, more specifically that of mining vehicles. One solution to this problem is replacing the combustion engine vehicles with electric vehicles. This also poses the problem of low power density. This paper proposes a solution of using supercapacitors and hybrid capacitors with the aim of investigating how they can affect the performance of electric vehicles. For this purpose, a background of fuel consumption and alternative solutions to the problem are discussed, a prototype was designed and built. It was found that when supercapacitors and hybrid capacitors were used in combin…
Compared regimes of NDVI and Rainfall in semi-arid regions of Africa
2006
International audience; Bi-monthly normalized difference vegetation index (NDVI) at an 8km spatial resolution from the advanced very high resolution radiometers (AVHRR) was used from 1981 to 1995 to analyse the vegetation response to rainfall supply in semi-arid regions of Africa. Within the 200-600 mm annual rainfall belt, for which the apparent NDVI response to rainfall was the strongest, three regions were selected which exhibited different patterns in their NDVI regimes and/or relationships with rainfall. The regions, located in western, southern and eastern Africa, were split into coherent sub-regions in terms of mean regime of photosynthetic activity through a cluster analysis. Overal…
Second-harmonic generation in surface periodically poled lithium niobate waveguides:On the role of multiphoton absorption
2008
Second harmonic generation is investigated in lithium niobate channels realized by proton exchange and quasi-phase-matched by surface periodic-poling. The reduction in conversion efficiency at high powers is interpreted in terms of multi-photon absorption via two-color terms, yielding an estimate of the dominating three-photon process.
Backcasting for desirable futures in Finnish forest-based firms
2020
Purpose In Finland, new forest-based sector (FBS) businesses are seen as important for the transition to the circular bioeconomy. The purpose of this study is to explore the transition of Finnish FBS companies to new business models. The aim is to understand how FBS companies define their ideal future states and related business models for the year 2030. Design/methodology/approach This study uses thematic interviews with managers from various FBS firms and companies from interfacing sectors. In the interviews, the key idea of backcasting was pursued when respondents discussed the desirable future states of their business. Findings The effort to achieve growth of the business and the appea…