Search results for "Beck"

Observable Variables in Thermoelectric Phenomena

2002

New transport equations for the thermoelectric phenomena have been deduced. All of the variables in this formulation are observable quantities. The limitations of the usual formulations, which work with nonobservable quantities, have been overcome. The electric potential can be measured by using auxiliary probes which connect the electronic conductor to a potentiometer. This observable electric potential depends on the nature of the probes but not on the room temperature where the potentiometer is placed. Also, we emphasize that absolute values for the thermoelectric power are in contradiction with the thermodynamic limitation of measuring electric potential differences in these systems. Th…

Towards a complete phylogeny of African Melastomateae : systematics of Dissotis and allies (Melastomataceae)

2020

Thermal potential of ion-exchange membranes and its application to thermoelectric power generation

2016

The low efficiency and high price of thermoelectric semiconductors has generated interest in unconventional forms of thermoelectric materials. In this article, ionic thermoelectricity has been studied with commercial ion-exchange membranes for different aqueous 1:1 electrolytes. The theory of thermal membrane potential has been derived taking into account the ionic heats of transport, the non-isothermal Donnan potentials, the temperature polarization, and the thermally-induced concentration polarization of the electrolyte. Also the generated thermoelectric power has been experimentally studied. The experiments show good agreement with the theory, and suggest ways for systematic improvement …

Long-term stability of phase-separated half-Heusler compounds

2015

Half-Heusler (HH) compounds have shown high figure of merit up to 1.5. Here, we address the long-term stability of n- and p-type HH materials. For this purpose, we investigated HH materials based on the Ti0.3Zr0.35Hf0.35NiSn-system after 500 cycles (1700 h) from 373 to 873 K. Both compounds exhibit a maximum Seebeck coefficient of |α|≈ 210 μV K(-1) and a phase separation into two HH phases. The dendritic microstructure is temperature resistant and upon cycling the changes in the microstructure are so marginal that the low thermal conductivity values (κ4 W m(-1) K(-1)) could be maintained. Our results emphasize that phase-separated HH compounds are suitable low cost materials and can lead to…

Resolving the true band gap of ZrNiSn half-Heusler thermoelectric materials

2015

N-type XNiSn (X = Ti, Zr, Hf) half-Heusler (HH) compounds possess excellent thermoelectric properties, which are believed to be attributed to their relatively high mobility. However, p-type XNiSn HH compounds have poor figures of merit, zT, compared to XCoSb compounds. This can be traced to the suppression of the magnitude of the thermopower at high temperatures. E_g = 2eS_(max)T_(max) relates the band gap to the thermopower peak. However, from this formula, one would conclude that the band gap of p-type XNiSn solid solutions is only one-third that of n-type XNiSn, which effectively prevents p-type XNiSn HHs from being useful thermoelectric materials. The study of p-type HH Zr_(1−x)Sc_xNiSn…

Characterization of thermoelectric and thermogravimetric properties of conductive PEDOT:PSS films blended with SWCNTs and PVA

2019

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was blended with polyvinyl alcohol (PVA) and single-walled carbon nanotube (SWCNT) filler to form composites with thermoelectric properties. Studied samples were obtained by drop coating and solution casting methods. Thermoelectric measurements of PEDOT:PSS demonstrated that the addition of 5 wt. % SWCNTs increased the Seebeck coefficient value from 8.0 μV/K to 23.6 μV/K, while in the case of PEDOT:PSS/PVA blended with 5 wt. % SWCNT Seebeck coefficient value of 20.3 μV/K was achieved. Thermogravimetric analysis showed slight SWCNT effect on thermal stability of the investigated systems.

An Approach on the Hydrogen Absorption in Carbon Black after Gamma Irradiation

2013

In this work, different samples of an industrial carbon black are used to study the hydrogen intake from an over pres-surized atmosphere and its changes due to alteration of its level of crystallinity produced by ¿-irradiation. The monitor-ing of the hydrogen adsorption was made by means of thermogravimetric analysis and by measurements of some elec-trical parameters as the Seebeck coefficient. X-ray diffraction shows that the irradiation diminishes the level of crystal-line perfection. These results show interesting possibilities to use carbon black as cheap hydrogen absorbers.

Vita et processus S. Thomae Cantuariensis super libertate ecclesiastica

1495

Sig. a-l8, m6, A4 L. gòt. - 2 tam. - 2 col. - 45 lín. - Esp. o min. p. inic. - Capçaleres

Distrofia Muscular de Duchenne y Becker: implicaciones cognitivas y conductuales

2021

La distrofia muscular de Duchenne (DMD; OMIM: 310200), es causada por la ausencia de distrofina; y la distrofia muscular de Becker (DMB; OMIM: 300376), es causada por una disminución o expresión anómala de distrofina. Al menos el 30% de los pacientes cursan con alteración cognitiva y conductual durante el neurodesarrollo. En esta investigación se pretenden estudiar los fenotipos cognitivos y conductuales asociados, en una muestra de pacientes españoles. Siendo el primer estudio cognitivo a nivel nacional. MÉTODO: 41 pacientes DMD, 19 pacientes DMB y 39 pacientes control. Rango de edades entre 3 y 16 años. Se valora el nivel cognitivo general del paciente (CI) y las funciones cognitivas espe…

Antropologia filosòfica i literatura: G. Anders interpreta S. Beckett

2004

Abstract: This paper is intended to stress the importance of studying the relationship between philosophy and literature, or, to put it more precisely, between philosophical anthropology and contemporary dramaturgy. To this purpose, it analyses a deep text that has gone largely unnoticed up to now, namely the interpretation, elaborated in 1955 by the writer and thinker Günther Anders, of one of the most radical and innovative revolutions in contemporary drama: Samuel Beckett’s En attendant Godot (Waiting for Godot). In addition to introducing the life and work of Anders’s, this paper presents the different sections of the central chapter of his most important work, Die Antiquierheit des Men…