Search results for "Merit"
showing 10 items of 135 documents
Thermal conductivity of half-Heusler superlattices
2014
Thin films and superlattices (SLs) of TiNiSn and ZrHfNiSn layers have been grown by dc magnetron sputtering on MgO (100) substrates to reduce the thermal conductivity, aiming for improvement of the thermoelectric figure of merit ZT. The thermal conductivity of 1 Wm−1K−1 was measured by the differential 3ω method for an SL with a periodicity of 8.8 nm. In addition to x-ray diffraction analysis of the SL crystal structure, smooth interfaces were confirmed by scanning/transmission electron microscopy.
Phase separation as a key to a thermoelectric high efficiency
2012
This work elucidates the possible reasons for the outstanding, but never reproduced thermoelectric properties of the doped Ti(0.5)Zr(0.25)Hf(0.25)NiSn Heusler compounds. The structural investigations done via synchrotron X-ray diffraction measurements and scanning electron microscope measurements, which clearly show that the microstructure consists of three temperature stable C1(b) phases with possible semi-coherent interfaces, are presented. The exceptional thermoelectric properties are due to this intrinsic phase separation. It is possible to reproduce the high Figure of Merit values with ZT = 1.2 at 830 K. Furthermore, the influence of doping different elements on the Sn position in this…
Unequal Attainments: Ethnic educational inequalities in ten Western countries
2014
Western countries have become increasingly diverse in recent decades and these demographic trends are certain to continue. The resulting ethnic diversity is a major challenge to policy-makers, who need to tackle issues of social justice and social integration. Education plays a pivotal role since it is the major stepping stone for the children of immigrants to successful economic integration and also plays a major role in social and political integration more generally since education gives access to the skills, resources and contacts which enable individuals to participate fully in the life of their society. Our central research questions are: Do the descendants of migrants experience equa…
Thermoelectric properties of Zn-doped Ca_(3)AlSb_(3)
2012
Polycrystalline samples of Ca_(3)Al_(1)−_(x)Zn_(x)Sb_(3), with x = 0.00, 0.01, 0.02, and 0.05 were synthesized via a combined ball milling and hot pressing technique and the influence of zinc as a dopant on the thermoelectric properties was studied and compared to the previously reported transport properties of sodium-doped Ca_(3)AlSb_(3). Consistent with the transport in the sodium-doped material, substitution of aluminum with zinc leads to p-type carrier conduction that can be sufficiently explained with a single parabolic band model. It is found that, while exhibiting higher carrier mobilities, the doping effectiveness of zinc is lower than that of sodium and the optimum carrier concentr…
A comparison among different kinds of stator lamination in tubular linear machines
2016
In this paper the authors perform a comparison among three different stator structures for a Tubular Permanent Magnet Linear Machine. Each structure is characterized by its own lamination which is expected to contribute to the overall performance of the machine. A detailed analysis of the main figures of merit of the three configurations has been carried out in order to identify the configuration with the best characteristics. Significant data such as flux distribution, rated voltage and current, force on the moved and power losses have been compared. The results show that the choice of a mixed stator lamination allows to improve the performance of these machines.
Misura delle performance finanziarie e patrimoniali delle aziende agricole: proposta operativa per un nuovo modello di rating per le aziende agricole
2012
La profonda evoluzione dei sistemi agricoli negli ultimi anni hanno accresciuto l'attenzione di tutti gli attori istituzionali ed economici rispetto alla problematica dell'accesso al credito per le imprese. Nel passato molto spesso il credito in agricoltura ha usufruito di regimi "speciali"; con l'implementazione delle regole di Basilea 2 (più di recente Basilea 3), le condizioni per l'accesso al credito si sono notevolmente irrigidite. Nell'ambito del settore agricolo, la pressoché assenza di bilanci certificati rende particolarmente difficoltosa questa valutazione. Nel presente lavoro, dopo aver analizzato la letteratura in materia di valutazione del merito creditizio delle aziende agrico…
HEMT for low-noise microwaves: CAD-oriented performance evaluation
1995
This paper shows how a graphic processing of low-noise HEMT's small signal parameters, allows evaluating and comparing the actual performance obtainable in front-end applications. HEMT's tradeoff charts which solve tradeoffs among the basic low-noise amplifier performance are reported. Figures of merit for microwave low-noise HEMT which represent a fast way of evaluating HEMT in actual working conditions and of selecting the proper transistor, are defined. As an example, the tradeoff charts and the figures of merit of two HEMT's (Fujitsu FHR02FH, Sony 2SK677) and a pseudomorphic-HEMT (Celeritek CFB001-03) are reported and compared with the data sheets. © 1995, IEEE. All rights reserved.
2-D approach to the analysis of semianechoic chambers using a hybrid technique
2003
Semianechoic chambers are the most widely used emplacements for electromagnetic compatibility (EMC) tests. In this work a new and efficient technique for the analysis of 2-D simplified model of a chamber with arbitrary absorber is introduced and validated Some advanced results are presented, and a 2-D figure of merit for studying the overall behaviour of the chamber is proposed.
Justicia y legitimidad de la desigualdad tras la crisis financiera
2009
La crisis no sólo ha puesto de manifiesto la desconexión entre economía real y financiera sino también ha permitido cuestionar, aunque tímidamente, el papel legitimador que a menudo corresponde a los atributos meritocráticos (esfuerzo, inteligencia, etc.) en el tipo de desigualdad a la que da lugar el sistema de mercado. Cuestionadas algunas de las bases (morales si se quiere) con las que se pretendía fundado pero también fundante el principio de justicia del capitalismo (la vieja cuestión de la desigualdad económica legítima en relación con la igualdad formal y de derechos en el seno de la ciudadanía, pero también el nuevo problema de los techos salariales, etc.) nos encontramos, querámosl…
Enhanced thermoelectric performance in the p-type half-Heusler (Ti/Zr/Hf)CoSb0.8Sn0.2 system via phase separation
2014
A novel approach for optimization of the thermoelectric properties of p-type Heusler compounds with a C1b structure was investigated. A successful recipe for achieving intrinsic phase separation in the n-type material based on the TiNiSn system is isoelectronic partial substitution of Ti with its heavier homologues Zr and Hf. We applied this concept to the p-type system MCoSb0.8Sn0.2 by a systematic investigation of samples with different compositions at the Ti position (M = Ti, Zr, Hf, Ti0.5Zr0.5, Zr0.5Hf0.5, and Ti0.5Hf0.5). We thus achieved an approximately 40% reduction of the thermal conductivity and a maximum figure of merit ZT of 0.9 at 700 °C. This is a 80% improvement in peak ZT fr…