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1

Longitudinal Spin Seebeck Effect  

NASA Astrophysics Data System (ADS)

The spin Seebeck effect (SSE) refers to the generation of a spin voltage as a result of a temperature gradient in magnetic materials [1-7]. Here, a spin voltage is a potential for electron spins to drive a nonequilibrium spin current; when a conductor is attached to a magnet with a finite spin voltage, it induces a spin injection into the conductor. The SSE is of crucial importance in spintronics and spin caloritronics, since it enables simple and versatile generation of a spin current from heat. The simplest and most straightforward setup of the SSE is the longitudinal configuration [4], in which a spin current flowing parallel to a temperature gradient is measured via the inverse spin Hall effect (ISHE). The longitudinal SSE device consists of a ferromagnetic or ferrimagnetic insulator (FI, e.g. YIG) covered with a paramagnetic metal (PM, e.g. Pt) film. When a temperature gradient is applied perpendicular to the FI/PM interface, an ISHE-induced voltage is generated in the PM layer. In this talk, we report the observation of the longitudinal SSE in various FI/PM systems and provide evidence that the longitudinal SSE is free from thermoelectric artefact [7], i.e., the anomalous Nernst effect caused by extrinsic magnetic proximity [8]. Then, we discuss the longitudinal SSE from an application point of view [6]. We thank E. Saitoh, S. Maekawa, G. E. W. Bauer, X.-F. Jin, H. Adachi, D. Hou, D. Tian, T. Kikkawa, A. Kirihara, and M. Ishida for their support and valuable discussions. [4pt] [1] K. Uchida et al., Nature 455, 778 (2008).[0pt] [2] K. Uchida et al., Nature Mater. 9, 894 (2010).[0pt] [3] C. M. Jaworski et al., Nature Mater. 9, 898 (2010).[0pt] [4] K. Uchida et al., Appl. Phys. Lett. 97, 172505 (2010).[0pt] [5] K. Uchida et al., Nature Mater. 10, 737 (2011).[0pt] [6] A. Kirihara et al., Nature Mater. 11, 686 (2012).[0pt] [7] T. Kikkawa et al., arXiv:1211.0139 (2012). [0pt] [8] S. Y. Huang et al., Phys. Rev. Lett. 109, 107204 (2012).

Uchida, Ken-Ichi

2013-03-01

2

Theory of the spin Seebeck effect  

NASA Astrophysics Data System (ADS)

The spin Seebeck effect refers to the generation of a spin voltage caused by a temperature gradient in a ferromagnet, which enables the thermal injection of spin currents from the ferromagnet into an attached nonmagnetic metal over a macroscopic scale of several millimeters. The inverse spin Hall effect converts the injected spin current into a transverse charge voltage, thereby producing electromotive force as in the conventional charge Seebeck device. Recent theoretical and experimental efforts have shown that the magnon and phonon degrees of freedom play crucial roles in the spin Seebeck effect. In this paper, we present the theoretical basis for understanding the spin Seebeck effect and briefly discuss other thermal spin effects.

Adachi, Hiroto; Uchida, Ken-ichi; Saitoh, Eiji; Maekawa, Sadamichi

2013-03-01

3

Theory of the spin Seebeck effect.  

PubMed

The spin Seebeck effect refers to the generation of a spin voltage caused by a temperature gradient in a ferromagnet, which enables the thermal injection of spin currents from the ferromagnet into an attached nonmagnetic metal over a macroscopic scale of several millimeters. The inverse spin Hall effect converts the injected spin current into a transverse charge voltage, thereby producing electromotive force as in the conventional charge Seebeck device. Recent theoretical and experimental efforts have shown that the magnon and phonon degrees of freedom play crucial roles in the spin Seebeck effect. In this paper, we present the theoretical basis for understanding the spin Seebeck effect and briefly discuss other thermal spin effects. PMID:23420561

Adachi, Hiroto; Uchida, Ken-ichi; Saitoh, Eiji; Maekawa, Sadamichi

2013-03-01

4

Exciton Seebeck effect in molecular systems.  

PubMed

We investigate the exciton dynamics under temperature difference with the hierarchical equations of motion. Through a nonperturbative simulation of the transient absorption of a heterogeneous trimer model, we show that the temperature difference causes exciton population redistribution and affects the exciton transfer time. It is found that one can reproduce not only the exciton population redistribution but also the change of the exciton transfer time induced by the temperature difference with a proper tuning of the site energies of the aggregate. In this sense, there exists a site energy shift equivalence for any temperature difference in a broad range. This phenomenon is similar to the Seebeck effect as well as spin Seebeck effect and can be named as exciton Seebeck effect. PMID:25106568

Yan, Yun-An; Cai, Shaohong

2014-08-01

5

Time resolved spin Seebeck effect experiments  

NASA Astrophysics Data System (ADS)

In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our thin film hybrid structures.

Roschewsky, Niklas; Schreier, Michael; Kamra, Akashdeep; Schade, Felix; Ganzhorn, Kathrin; Meyer, Sibylle; Huebl, Hans; Geprägs, Stephan; Gross, Rudolf; Goennenwein, Sebastian T. B.

2014-05-01

6

Seebeck effect at the atomic scale.  

PubMed

The atomic variations of electronic wave functions at the surface and electron scattering near a defect have been detected unprecedentedly by tracing thermoelectric voltages given a temperature bias [Cho et al., Nat. Mater. 12, 913 (2013)]. Because thermoelectricity, or the Seebeck effect, is associated with heat-induced electron diffusion, how the thermoelectric signal is related to the atomic-scale wave functions and what the role of the temperature is at such a length scale remain very unclear. Here we show that coherent electron and heat transport through a pointlike contact produces an atomic Seebeck effect, which is described by the mesoscopic Seebeck coefficient multiplied by an effective temperature drop at the interface. The mesoscopic Seebeck coefficient is approximately proportional to the logarithmic energy derivative of local density of states at the Fermi energy. We deduced that the effective temperature drop at the tip-sample junction could vary at a subangstrom scale depending on atom-to-atom interaction at the interface. A computer-based simulation method of thermoelectric images is proposed, and a point defect in graphene was identified by comparing experiment and the simulation of thermoelectric imaging. PMID:24745445

Lee, Eui-Sup; Cho, Sanghee; Lyeo, Ho-Ki; Kim, Yong-Hyun

2014-04-01

7

Seebeck Effect at the Atomic Scale  

NASA Astrophysics Data System (ADS)

The atomic variations of electronic wave functions at the surface and electron scattering near a defect have been detected unprecedentedly by tracing thermoelectric voltages given a temperature bias [Cho et al., Nat. Mater. 12, 913 (2013)]. Because thermoelectricity, or the Seebeck effect, is associated with heat-induced electron diffusion, how the thermoelectric signal is related to the atomic-scale wave functions and what the role of the temperature is at such a length scale remain very unclear. Here we show that coherent electron and heat transport through a pointlike contact produces an atomic Seebeck effect, which is described by the mesoscopic Seebeck coefficient multiplied by an effective temperature drop at the interface. The mesoscopic Seebeck coefficient is approximately proportional to the logarithmic energy derivative of local density of states at the Fermi energy. We deduced that the effective temperature drop at the tip-sample junction could vary at a subangstrom scale depending on atom-to-atom interaction at the interface. A computer-based simulation method of thermoelectric images is proposed, and a point defect in graphene was identified by comparing experiment and the simulation of thermoelectric imaging.

Lee, Eui-Sup; Cho, Sanghee; Lyeo, Ho-Ki; Kim, Yong-Hyun

2014-04-01

8

Simple Demonstration of the Seebeck Effect  

ERIC Educational Resources Information Center

In this article we propose a simple and low-cost experimental set-up through which science educators can demonstrate the Seebeck effect using a thermocouple and an instrumentation amplifier. The experiment can be set up and conducted during a 1-hour laboratory session. (Contains 3 tables and 3 figures.)

Molki, Arman

2010-01-01

9

Photo-Seebeck effect of conjugated polymers  

NASA Astrophysics Data System (ADS)

Photo-Seebeck effect of conjugated polymers (CPs) from thiophenes and selenophenes were explored for a flexible energy conversion device. CP films were obtained by oxidative polymerizations, which grow conductive channels as polymerization proceeds. Through an optimized polymerization condition, highly conductive CP films were obtained with lower oxidation level. Taking advantage of their high electrical conductivity, the CP films were further explored as a transparent photo-thermo-electric film, because their absorption energy is easily controlled by the degree of oxidation or doping. Upon exposure to a near IR source, the CP films got heated, to result in temperature rise on a substrate. The generated heat was effectively converted into electricity to confirm a photo-Seebeck effect from the CP film under a light exposure. Efficient near-IR photothermal effect and heat to electric conversion have been realized in CP films that could benefit in exploiting multifunctional film displays, invisible NIR sensors, and hybrid energy harvesters.

Kim, B.; Lim, H.; Kim, E.

2014-08-01

10

Magnons, Spin Current and Spin Seebeck Effect  

NASA Astrophysics Data System (ADS)

When metals and semiconductors are placed in a temperature gradient, the electric voltage is generated. This mechanism to convert heat into electricity, the so-called Seebeck effect, has attracted much attention recently as the mechanism for utilizing wasted heat energy. [1]. Ferromagnetic insulators are good conductors of spin current, i.e., the flow of electron spins [2]. When they are placed in a temperature gradient, generated are magnons, spin current and the spin voltage [3], i.e., spin accumulation. Once the spin voltage is converted into the electric voltage by inverse spin Hall effect in attached metal films such as Pt, the electric voltage is obtained from heat energy [4-5]. This is called the spin Seebeck effect. Here, we present the linear-response theory of spin Seebeck effect based on the fluctuation-dissipation theorem [6-8] and discuss a variety of the devices. [4pt] [1] S. Maekawa et al, Physics of Transition Metal Oxides (Springer, 2004). [0pt] [2] S. Maekawa: Nature Materials 8, 777 (2009). [0pt] [3] Concept in Spin Electronics, eds. S. Maekawa (Oxford University Press, 2006). [0pt] [4] K. Uchida et al., Nature 455, 778 (2008). [0pt] [5] K. Uchida et al., Nature Materials 9, 894 (2010) [0pt] [6] H. Adachi et al., APL 97, 252506 (2010) and Phys. Rev. B 83, 094410 (2011). [0pt] [7] J. Ohe et al., Phys. Rev. B (2011) [0pt] [8] K. Uchida et al., Appl. Phys. Lett. 97, 104419 (2010).

Maekawa, Sadamichi

2012-02-01

11

Surface sensitivity of the spin Seebeck effect  

NASA Astrophysics Data System (ADS)

We have investigated the influence of the interface quality on the spin Seebeck effect (SSE) of the bilayer system yttrium iron garnet (YIG)-platinum (Pt). The magnitude and shape of the SSE is strongly influenced by mechanical treatment of the YIG single crystal surface. We observe that the saturation magnetic field ( H sat SSE) for the SSE signal increases from 55.3 mT to 72.8 mT with mechanical treatment. The change in the magnitude of H sat SSE can be attributed to the presence of a perpendicular magnetic anisotropy due to the treatment induced surface strain or shape anisotropy in the Pt/YIG system. Our results show that the SSE is a powerful tool to investigate magnetic anisotropy at the interface.

Aqeel, A.; Vera-Marun, I. J.; van Wees, B. J.; Palstra, T. T. M.

2014-10-01

12

Intrinsic Spin Seebeck Effect in Gold  

NASA Astrophysics Data System (ADS)

In Spin Seebeck Effect (SSE), a pure spin current can be generated by a temperature gradient (?T) and detected by the inverse spin Hall effect usually by Pt. Due to the propensity of out-of-plane ?zT through substrate, the SSE in the transverse configuration with an in-plane ?xT has been shown contaminated by the anomalous Nernst effect.footnotetextS. Y. Huang, et al. Phys. Rev. Lett. 107, 216604 (2011) The SSE in the longitudinal configuration with ?zT suffers from the magnetic proximity effect (MPE) of Pt in contact with a ferromagnetic material thus also contaminated.footnotetextS. Y. Huang, et al. Phys. Rev. Lett. 109, 107204 (2012) In this work, we demonstrate that Au does not exhibit MPE and reveals the intrinsic SSE. In contrast to Pt/YIG, Au/YIG shows no anomalous Hall signals, very weak inverse MR, and non-monotonic thickness dependence of spin thermal voltage, thus very weak if any MPE. Our results place an upper limit to the intrinsic SSE of 0.1?V/K at the Au thickness of 8nm, two orders of magnitude smaller than that in Pt/YIG. Spin-polarized density-functional calculations also show a sizable Pt but a negligible Au magnetic moment in contact with YIG, in agreement with experiments.

Qu, Danru; Huang, Ssu-Yen; Hu, Jun; Wu, Ruqian; Chien, Chia-Ling

2013-03-01

13

Spin Seebeck effect: Thinks globally but acts locally  

NASA Astrophysics Data System (ADS)

Experiments on magnetic insulators and semiconductors imply that the spin Seebeck effect is conceptually different from the standard thermoelectric effect, launching new challenges for both theorists and experimentalists in spintronics.

Sinova, Jairo

2010-11-01

14

Seebeck effect in carbon fiber-reinforced cement  

SciTech Connect

The Seebeck effect in carbon fiber-reinforced cement paste was found to involve electrons from the cement matrix and holes from the biers. The two contributions were equal at the percolation threshold, with a fiber content between 0.5 and 1.0% by mass of cement. The hole contribution increased monotonically with increasing fiber content below and above the percolation threshold. The fiber addition increased the linearity and reversibility of the Seebeck effect. Silica fume and latex as admixtures had minor influence on the Seebeck effect. The Seebeck effect in concrete is of interest because it gives the concrete the ability to sense its own temperature. No attached or embedded sensor is needed since the concrete itself is the sensor. This means low cost, high durability, large sensing volume, and absence of mechanical property degradation due to embedded sensors. As the temperature affects the performance and reliability of concrete, its detection is valuable.

Wen, S.; Chung, D.D.L.

1999-12-01

15

Anisotropic magnetothermal transport and spin Seebeck effect  

NASA Astrophysics Data System (ADS)

The anisotropic properties of thermal transport in insulating or conducting ferromagnets are derived on the basis of the Onsager reciprocity relations applied to a magnetic system. It is shown that the angular dependence of the temperature gradient takes the same form as that of the anisotropic magnetoresistance, including anomalous and planar Hall contributions. The measured thermocouple generated between the extremities of the nonmagnetic electrode in thermal contact to the ferromagnet follows this same angular dependence. The sign and amplitude of the magnetovoltaic signal is controlled by the difference of the Seebeck coefficients of the thermocouple.

Wegrowe, J.-E.; Drouhin, H.-J.; Lacour, D.

2014-03-01

16

Giant spin Seebeck effect in a non-magnetic material.  

PubMed

The spin Seebeck effect is observed when a thermal gradient applied to a spin-polarized material leads to a spatially varying transverse spin current in an adjacent non-spin-polarized material, where it gets converted into a measurable voltage. It has been previously observed with a magnitude of microvolts per kelvin in magnetically ordered materials, ferromagnetic metals, semiconductors and insulators. Here we describe a signal in a non-magnetic semiconductor (InSb) that has the hallmarks of being produced by the spin Seebeck effect, but is three orders of magnitude larger (millivolts per kelvin). We refer to the phenomenon that produces it as the giant spin Seebeck effect. Quantizing magnetic fields spin-polarize conduction electrons in semiconductors by means of Zeeman splitting, which spin-orbit coupling amplifies by a factor of ?25 in InSb. We propose that the giant spin Seebeck effect is mediated by phonon-electron drag, which changes the electrons' momentum and directly modifies the spin-splitting energy through spin-orbit interactions. Owing to the simultaneously strong phonon-electron drag and spin-orbit coupling in InSb, the magnitude of the giant spin Seebeck voltage is comparable to the largest known classical thermopower values. PMID:22785317

Jaworski, C M; Myers, R C; Johnston-Halperin, E; Heremans, J P

2012-07-12

17

Longitudinal Spin Seebeck Effect Free from the Proximity Nernst Effect  

NASA Astrophysics Data System (ADS)

This Letter provides evidence for intrinsic longitudinal spin Seebeck effects (LSSEs) that are free from the anomalous Nernst effect (ANE) caused by an extrinsic proximity effect. We report the observation of LSSEs in Au/Y3Fe5O12 (YIG) and Pt/Cu/YIG systems, showing that the LSSE appears even when the mechanism of the proximity ANE is clearly removed. In the conventional Pt/YIG structure, furthermore, we separate the LSSE from the ANE by comparing the voltages in different magnetization and temperature-gradient configurations; the ANE contamination was found to be negligibly small even in the Pt/YIG structure.

Kikkawa, T.; Uchida, K.; Shiomi, Y.; Qiu, Z.; Hou, D.; Tian, D.; Nakayama, H.; Jin, X.-F.; Saitoh, E.

2013-02-01

18

Intrinsic Spin Seebeck Effect in Au/YIG  

NASA Astrophysics Data System (ADS)

The acute magnetic proximity effects in Pt/YIG compromise the suitability of Pt as a spin current detector. We show that Au/YIG, with no anomalous Hall effect and a negligible magnetoresistance, allows the measurements of the intrinsic spin Seebeck effect with a magnitude much smaller than that in Pt/YIG. The experiment results are consistent with the spin polarized density functional calculations for Pt with a sizable and Au with a negligible magnetic moment near the interface with YIG.

Qu, D.; Huang, S. Y.; Hu, Jun; Wu, Ruqian; Chien, C. L.

2013-02-01

19

Charging of Heated Colloidal Particles Using the Electrolyte Seebeck Effect  

E-print Network

We propose a novel actuation mechanism for colloids, which is based on the Seebeck effect of the electrolyte solution: Laser heating of a nonionic particle accumulates in its vicinity a net charge Q, which is proportional to the excess temperature at the particle surface. The corresponding long-range thermoelectric field provides a tool for controlled interactions with nearby beads or with additional molecular solutes. An external field Eext drags the thermocharged particle at a velocity that depends on its size and absorption properties; the latter point could be particularly relevant for separating carbon nanotubes according to their electronic band structure.

Arghya Majee; Alois Würger

2014-01-29

20

Tailoring of Seebeck coefficient with surface roughness effects in silicon sub-50-nm films  

PubMed Central

The effect of surface roughness on the Seebeck coefficient in the sub-50-nm scale silicon ultra thin films is investigated theoretically using nonequilibrium Green's function formalism. For systematic studies, the surface roughness is modelled by varying thickness periodically with square wave profile characterized by two parameters: amplitude (A0) and wavelength (?). Since high Seebeck coefficient is obtained if the temperature difference between the ends of device produces higher currents and higher induced voltages, we investigate how the generated current and induced voltage is affected with increasing A0 and ?. The theoretical investigations show that pseudoperiodicity of the device structure gives rise to two effects: firstly the threshold energy at which the transmission of current starts is shifted towards higher energy sides and secondly transmission spectra of current possess pseudobands and pseudogaps. The width of the pseudobands and their occupancies determine the total generated current. It is found that current decreases with increasing A0 but shows a complicated trend with ?. The trends of threshold energy determine the trends of Seebeck voltage with roughness parameters. The increase in threshold energy makes the current flow in higher energy levels. Thus, the Seebeck voltage, i.e. voltage required to nullify this current, increases. Increase in Seebeck voltage results in increase in Seebeck coefficient. We find that threshold energy increases with increasing A0 and frequency (1/?). Hence, Seebeck voltage and Seebeck coefficient increase vice versa. It is observed that Seebeck coefficient is tuneable with surface roughness parameters. PMID:22390685

2012-01-01

21

Designing a study of the Spin Seebeck Effect  

NASA Astrophysics Data System (ADS)

The Spin Seebeck Effect (SSE) refers to the recently discovered generation of a spin voltage as a result of an applied temperature gradient. The SSE has been observed in ferromagnetic (FM) metals, semiconductors, and insulators. This area of research has attracted much interest because it may provide a means to make use of waste heat from electronic devices. While several theories have been presented, there are still open questions regarding the physical mechanism of this effect. Recent experimental evidence suggests that magnons and phonons play a role in thermal spin physics; however, the experiments done to date are performed primarily through detection of a voltage via the Inverse Spin Hall Effect that is due to the steady-state accumulation of a spin distribution across the FM material and consequently provide only indirect information on the magnons. Here we will discuss an experimental setup that we have designed to explore the role of magnons in the SSE using Brillouin light scattering.

Riley, Grant; Liu, Jason; Roberts, Gerri; Buchanan, Kristen

2012-10-01

22

Thermoelectric Seebeck effect in oxide-based resistive switching memory  

NASA Astrophysics Data System (ADS)

Reversible resistive switching induced by an electric field in oxide-based resistive switching memory shows a promising application in future information storage and processing. It is believed that there are some local conductive filaments formed and ruptured in the resistive switching process. However, as a fundamental question, how electron transports in the formed conductive filament is still under debate due to the difficulty to directly characterize its physical and electrical properties. Here we investigate the intrinsic electronic transport mechanism in such conductive filament by measuring thermoelectric Seebeck effects. We show that the small-polaron hopping model can well describe the electronic transport process for all resistance states, although the corresponding temperature-dependent resistance behaviours are contrary. Moreover, at low resistance states, we observe a clear semiconductor–metal transition around 150?K. These results provide insight in understanding resistive switching process and establish a basic framework for modelling resistive switching behaviour.

Wang, Ming; Bi, Chong; Li, Ling; Long, Shibing; Liu, Qi; Lv, Hangbing; Lu, Nianduan; Sun, Pengxiao; Liu, Ming

2014-08-01

23

Nonlinear thermokinetic phenomena due to the Seebeck effect.  

PubMed

We propose a novel mechanism to produce nonlinear thermokinetic vortex flows around a circular cylinder with ideally high thermal conductivity in an electrolyte. That is, the nonlinear thermokinetic slip velocity, which is proportional to the square of the temperature gradient [?(T)0(2)], is derived based on the electrolyte Seebeck effect, heat conduction equation, and Helmholtz–Smoluchowski formula. Different from conventional linear thermokinetic theory, our theory predicts that the inversion of the temperature gradient does not change the direction of the thermokinetic flows and thus a Janus particle using this phenomenon can move to the both hotter and colder regions in a temperature gradient field by changing the direction of its dielectric end. Our findings bridge the gap between the electro- and thermo-kinetic phenomena and provide an integrated physical viewpoint for the interface science. PMID:25003210

Sugioka, Hideyuki

2014-07-22

24

Thermoelectric Seebeck effect in oxide-based resistive switching memory  

PubMed Central

Reversible resistive switching induced by an electric field in oxide-based resistive switching memory shows a promising application in future information storage and processing. It is believed that there are some local conductive filaments formed and ruptured in the resistive switching process. However, as a fundamental question, how electron transports in the formed conductive filament is still under debate due to the difficulty to directly characterize its physical and electrical properties. Here we investigate the intrinsic electronic transport mechanism in such conductive filament by measuring thermoelectric Seebeck effects. We show that the small-polaron hopping model can well describe the electronic transport process for all resistance states, although the corresponding temperature-dependent resistance behaviours are contrary. Moreover, at low resistance states, we observe a clear semiconductor–metal transition around 150?K. These results provide insight in understanding resistive switching process and establish a basic framework for modelling resistive switching behaviour. PMID:25141267

Wang, Ming; Bi, Chong; Li, Ling; Long, Shibing; Liu, Qi; Lv, Hangbing; Lu, Nianduan; Sun, Pengxiao; Liu, Ming

2014-01-01

25

Thermoelectric Seebeck effect in oxide-based resistive switching memory.  

PubMed

Reversible resistive switching induced by an electric field in oxide-based resistive switching memory shows a promising application in future information storage and processing. It is believed that there are some local conductive filaments formed and ruptured in the resistive switching process. However, as a fundamental question, how electron transports in the formed conductive filament is still under debate due to the difficulty to directly characterize its physical and electrical properties. Here we investigate the intrinsic electronic transport mechanism in such conductive filament by measuring thermoelectric Seebeck effects. We show that the small-polaron hopping model can well describe the electronic transport process for all resistance states, although the corresponding temperature-dependent resistance behaviours are contrary. Moreover, at low resistance states, we observe a clear semiconductor-metal transition around 150?K. These results provide insight in understanding resistive switching process and establish a basic framework for modelling resistive switching behaviour. PMID:25141267

Wang, Ming; Bi, Chong; Li, Ling; Long, Shibing; Liu, Qi; Lv, Hangbing; Lu, Nianduan; Sun, Pengxiao; Liu, Ming

2014-01-01

26

Communication Role of moisture in the Seebeck effect in cement-based materials  

E-print Network

). Cement and Concrete Research 35 (2005) 810­812 #12;cement, water, silica fume (if applicable) and fibers; Silica fume; Thermoelectric 1. Introduction The Seebeck effect is a thermoelectric effect in which charge. Experimental methods The cement used was Portland cement (Type I) from Lafarge (Southfield, MI). The silica

Chung, Deborah D.L.

27

Transverse spin Seebeck effect versus anomalous and planar Nernst effects in Permalloy thin films.  

PubMed

Transverse magnetothermoelectric effects are studied in Permalloy thin films grown on MgO and GaAs substrates and compared to those grown on suspended SiN(x) membranes. The transverse voltage along platinum strips patterned on top of the Permalloy films is measured versus the external magnetic field as a function of the angle and temperature gradients. After the identification of the contribution of the planar and anomalous Nernst effects, we find an upper limit for the transverse spin Seebeck effect, which is several orders of magnitude smaller than previously reported. PMID:24237554

Schmid, M; Srichandan, S; Meier, D; Kuschel, T; Schmalhorst, J-M; Vogel, M; Reiss, G; Strunk, C; Back, C H

2013-11-01

28

Extracting the effective mass of electrons in transparent conductive oxide thin films using Seebeck coefficient  

NASA Astrophysics Data System (ADS)

A method is proposed that combines Seebeck coefficient and carrier concentration to determine the electron effective mass of transparent conductive oxide (TCO) thin films. Experiments were conducted to test the validity of this approach on the transparent conductive Ga-doped ZnO thin films deposited by magnetron sputtering. An evident agreement of the calculated electron effective mass of the films is observed between the proposed approach and the previous studies. Besides, the optical carrier concentration and mobility derived from the calculated electron effective mass and spectroscopic ellipsometry using a complex dielectric function are consistent with those from direct Hall-effect measurement. The agreements suggest that Seebeck coefficient can serve as an alternative tool for extracting the effective mass of electrons in TCO films.

Wang, Yaqin; Zhu, Junhao; Tang, Wu

2014-05-01

29

Magnon spin-current theory for the longitudinal spin-Seebeck effect  

NASA Astrophysics Data System (ADS)

We present a theoretical model for the longitudinal spin-Seebeck effect (LSSE) in bilayers made of a ferromagnetic insulator (FMI), such as yttrium iron garnet (YIG), and a normal metal (NM), such as platinum (Pt), that relies on the bulk magnon spin current created by the temperature gradient across the thickness of the FMI. We show that the spin current pumped into the NM layer by the magnon accumulation in the FMI provides continuity of the spin current at the FMI/NM interface and is essential for the existence of the longitudinal spin-Seebeck effect. The results of the theory are in good agreement with experimental data for the variation of the LSSE with the sample temperature and with the FMI layer thickness in YIG/Pt bilayers.

Rezende, S. M.; Rodríguez-Suárez, R. L.; Cunha, R. O.; Rodrigues, A. R.; Machado, F. L. A.; Fonseca Guerra, G. A.; Lopez Ortiz, J. C.; Azevedo, A.

2014-01-01

30

Magneto-Seebeck effect in R FeAsO (R =rare earth) compounds: Probing the magnon drag scenario  

NASA Astrophysics Data System (ADS)

We investigate the Seebeck effect in R FeAsO (R =rare earth) compounds as a function of temperature and magnetic field up to 30 T. The Seebeck curves are characterized by a broad negative bump around 50 K, which is sample dependent and strongly enhanced by the application of a magnetic field. A model for the temperature and field dependence of the magnon drag contribution to the Seebeck effect by antiferromagnetic (AFM) spin fluctuation is developed. It accounts for the magnitude and scaling properties of such bump feature in our experimental data in LaFeAsO. This analysis accounts for the apparent inconsistency of literature Seebeck effect data on these compounds and has the potential to extract precious information on the coupling between electrons and AFM spin fluctuations in these parent compound systems, with implications on the pairing mechanism of the related superconducting compounds.

Caglieris, F.; Braggio, A.; Pallecchi, I.; Provino, A.; Pani, M.; Lamura, G.; Jost, A.; Zeitler, U.; Galleani D'Agliano, E.; Manfrinetti, P.; Putti, M.

2014-10-01

31

Seebeck coefficient of one electron  

NASA Astrophysics Data System (ADS)

The Seebeck coefficient of one electron, driven thermally into a semiconductor single-electron box, is investigated theoretically. With a finite temperature difference ?T between the source and charging island, a single electron can charge the island in equilibrium, directly generating a Seebeck effect. Seebeck coefficients for small and finite ?T are calculated and a thermally driven Coulomb staircase is predicted. Single-electron Seebeck oscillations occur with increasing ?T, as one electron at a time charges the box. A method is proposed for experimental verification of these effects.

Durrani, Zahid A. K.

2014-03-01

32

Surface polarization enhanced Seebeck effects in vertical multi-layer metal-polymer-metal thin-film devices.  

PubMed

We explore a new mechanism to develop Seebeck effects by using temperature-dependent surface polarization based on vertical multi-layer Al-P3HT:PCBM-Al thin-film devices. Here, the temperature-dependent surface polarization functions as an additional driving force, as compared with the traditional driving force from the entropy difference, to diffuse the charge carriers under a temperature gradient towards the development of Seebeck effects. The temperature-dependent surface polarization is essentially generated by both the thermally dependent polarization through the charge-phonon coupling mechanism and the thermally modulated interface dipoles by Fermi electrons. It is noted that the entropy difference often causes an inverse relationship between the Seebeck coefficient and electrical conductivity in thermoelectric developments. However, this temperature-dependent surface polarization provides a mechanism allowing a co-operative relationship between the Seebeck coefficient and electrical conductivity. We demonstrate simultaneously the enhanced Seebeck coefficient and electrical conductivity by using the dielectric interface through the temperature-dependent surface polarization to diffuse charge carriers in the Al-MoO3-P3HT:PCBM-Al thin-film device. PMID:25213557

Liu, Qing; Hu, Dehua; Wang, Hongfeng; Stanford, Michael; Wang, Hsin; Hu, Bin

2014-10-28

33

Planar Nernst effect and Spin dependent Seebeck effect on Py/Ag thin films  

NASA Astrophysics Data System (ADS)

We are reporting a systematic study of planar Nernst effect (PNE) and Spin dependent Seebeck effect (SDSE) measurements and their relation to the Anisotropic Magneto Resistance (AMR) on Py thin films grown on SiOx substrates by magnetron sputtering. A 30nm thick Py film was followed by a 15nm of Ag cross electrodes. An in-situ mask exchanging system was allowed the Py and Ag to grow without breaking the vacuum. The sample was placed on top of two thermal baths which were independently controlled by a PID controller. A constant temperature gradient of 15K/cm was applied along the sample and the resultant voltages across the Ag electrodes were measured by nanovoltmeters as the field was swept. In measuring AMR no thermal gradient was applied, and a constant current was applied using a function generator. Both PNE and SDSE showed an AMR like field dependence and angular dependence. SDSE showed a Cos^2 (?) angular dependence and PNE showed a Sin (2?) angular dependence. AMR showed the same angular dependence along the Py film and across the Py film respectively. This suggests both PNE and SDSE behave similar to the AMR in thin films.

Jayathilaka, Priyanga; Belyea, Dustin; Eggers, Tatiana; Kirby, Hillary; Miller, Casey W.

2013-03-01

34

Investigation of the magnetic properties of insulating thin films using the longitudinal spin Seebeck effect  

NASA Astrophysics Data System (ADS)

The longitudinal spin Seebeck effect is used as a detector for the magnetic properties and switching characteristics of magnetic thin insulating films. We use a 300 nm and a 20 nm thick Yttrium Iron Garnet (YIG, Y3Fe5O12) film prepared by pulsed laser deposition and afterwards coated by platinum for the detection of the thermally excited magnons by the inverse spin Hall effect. The inverse spin Hall signals reveal a magnetic uniaxial anisotropy along the direction of the platinum stripe in the thicker film. For the thin film we find a more isotropic behavior, which is complementarily observed using the magnetoresistance occurring at the platinum/YIG interface. We explain our results on the basis of x-ray diffraction data, which reveal a miscut of the substrate and film surface and an expansion of the YIG lattice. Both findings favor a growth-induced magnetic anisotropy that we observe.

Kehlberger, A.; Jakob, G.; Onbasli, M. C.; Kim, D. H.; Ross, C. A.; Kläui, M.

2014-05-01

35

Spin-dependent Seebeck effect in non-local spin valve devices  

NASA Astrophysics Data System (ADS)

We performed measurements of Py/Cu and Py/Ag lateral spin valves as a function of injection current direction and magnitude. Above a "critical" current, there is an unexpected dependence of spin injection on current direction. Positive currents show higher polarization of spin injection than negative. This implies that in addition to current-induced spin injection, there is a thermally induced injection from a spin-dependent Seebeck effect. A temperature gradient in the Py electrode, caused by Joule heating, is responsible for injecting excess spins into the non-magnetic channel. This effect has important consequences for understanding high-current spin-based devices, such as spin transfer torque devices.

Erekhinsky, Mikhail; Casanova, Fèlix; Schuller, Ivan K.; Sharoni, Amos

2012-05-01

36

A novel strongly correlated electronic thin-film laser energy/power meter based on anisotropic Seebeck effect  

NASA Astrophysics Data System (ADS)

Strongly correlated electronic (SCE) materials including high-temperature superconducting cuprate and colossal magnetoresistance manganite thin films demonstrate tremendous anisotropic Seebeck effect which makes them very promising for developing high-performance laser detectors. In this work, laser-induced thermoelectric voltage (LITV) signals with nanosecond response time have been measured in SCE La1- x Pb x MnO3 thin films based on anisotropic Seebeck effect at room temperature. The magnitude of the LITV signals increases linearly with laser energy/power density in a wide range of laser wavelengths from ultraviolet, visible to infrared based on which a novel SCE thin-film laser energy/power meter has been developed.

Zhang, G.-Y.; Zhang, H.; Tan, S.-L.; Zhang, P.-X.; Tseng, T.-Y.; Habermeier, H.-U.; Lin, C.-T.; Singjai, P.

2014-09-01

37

Unambiguous separation of the inverse spin Hall and anomalous Nernst effects within a ferromagnetic metal using the spin Seebeck effect  

NASA Astrophysics Data System (ADS)

The longitudinal spin Seebeck effect is measured on the ferromagnetic insulator Fe3O4 with the ferromagnetic metal Co0.2Fe0.6B0.2 (CoFeB) as the spin detector. By using a non-magnetic spacer material between the two materials (Ti), it is possible to decouple the two ferromagnetic materials and directly observe pure spin flow from Fe3O4 into CoFeB. It is shown that in a single ferromagnetic metal, the inverse spin Hall effect (ISHE) and anomalous Nernst effect (ANE) can occur simultaneously with opposite polarity. Using this and the large difference in the coercive fields between the two magnets, it is possible to unambiguously separate the contributions of the spin Seebeck effect from the ANE and observe the degree to which each effect contributes to the total response. These experiments show conclusively that the ISHE and ANE in CoFeB are separate phenomena with different origins and can coexist in the same material with opposite response to a thermal gradient.

Wu, Stephen M.; Hoffman, Jason; Pearson, John E.; Bhattacharya, Anand

2014-09-01

38

Cu Doping Effect on Electrical Resistivity and Seebeck Coefficient of Perovskite-Type LaFeO3 Ceramics  

NASA Astrophysics Data System (ADS)

Perovskite-type LaFe1-xCuxO3 (x = 0.10, 0.14, 0.18) solid solution is prepared with the conventional solid-state reaction technique. The electrical resistivity and the Seebeck coefficient are measured in the temperature range 473-1073K to elucidate the Cu doping effect on the thermoelectric properties of the LaFeO3. The electrical resisitivity of LaFe1-x Cux O3 shows semiconducting behavior. The temperature dependence of the electrical resistivity indicates that the adiabatic small-polaron hopping mechanism is dominant for their electric transportations. The activation energy decreases with the increasing Cu content as well as the increasing temperature. The Seebeck coefficient changes from a negative value to a positive value around 510 K, and increases with rising temperature up to 710K, then becomes saturated around 200?V/K. The Seebeck coefficient decreases with the substitution of Cu atoms in the temperature range of 573-1073 K, while the electrical resistivity decreases with the substitution of Cu atoms in the whole measured temperature. Overall the power factor increases with rising temperature, and the highest value of power factor is 54 ?W/K2 m for x = 0.10 of Cu doping.

Wang, Hong-Chao; Wang, Chun-Lei; Zhang, Jia-Liang; Zhao, Ming-Lei; Liu, Jian; Su, Wen-Bin; Yin, Na; Mei, Liang-Mo

2009-10-01

39

High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture  

SciTech Connect

Conductive polymers are of particular interest for thermoelectric applications due to their low thermal conductivity and relatively high electrical conductivity. In this study, commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) was used in a hybrid metal/polymer/metal thin film design in order to achieve a high Seebeck coefficient with the value of 252lV/k on a relatively low temperature scale. Polymer film thickness was varied in order to investigate its influence on the Seebeck effect. The high Seebeck coefficient indicates that the metal/polymer/metal design can develop a large entropy difference in internal energy of charge carriers between high and low-temperature metal electrodes to develop electrical potential due to charge transport in conducting polymer film through metal/polymer interface. Therefore, the metal/polymer/metal structure presents a new design to combine inorganic metals and organic polymers in thin-film form to develop Seebeck devices

Stanford, Michael G [ORNL; Wang, Hsin [ORNL; Ivanov, Ilia N [ORNL; Hu, Bin [University of Tennessee, Knoxville (UTK)

2012-01-01

40

Role of bulk-magnon transport in the temporal evolution of the longitudinal spin-Seebeck effect  

NASA Astrophysics Data System (ADS)

We present the temporal evolution of the longitudinal spin Seebeck effect in a YIG|Pt bilayer system. Our findings reveal that this effect is a submicrosecond fast phenomenon governed by the thermal-magnon diffusion along the thermal gradient inside the magnetic material. A comparison of experimental results with the thermal-driven magnon-diffusion model demonstrates that the temporal behavior of this effect depends on the time development of the temperature gradient in the magnetic material close to the interface. The effective thermal-magnon diffusion length for the YIG|Pt system is estimated to be around 500 nm.

Agrawal, M.; Vasyuchka, V. I.; Serga, A. A.; Kirihara, A.; Pirro, P.; Langner, T.; Jungfleisch, M. B.; Chumak, A. V.; Papaioannou, E. Th.; Hillebrands, B.

2014-06-01

41

Platinum thickness dependence and annealing effect of the spin-Seebeck voltage in platinum/yttrium iron garnet structures  

NASA Astrophysics Data System (ADS)

We investigate the substrate annealing effect of thermoelectric voltage induced by the spin-Seebeck effect in Pt/polycrystalline yttrium iron garnet Y3Fe5O12 (YIG) structures with different Pt thicknesses. The thermoelectric voltage is increased by decreasing the Pt thickness to 1.9 nm as well as by annealing. Annealing at 1073 K for 5 h enhances the thermoelectric voltage up to 7.4 µV/K in structures with 1.9 nm Pt thickness.

Saiga, Yuta; Mizunuma, Kotaro; Kono, Yasushi; Ryu, Jeong Chun; Ono, Hiroshi; Kohda, Makoto; Okuno, Eiichi

2014-09-01

42

Cu Doping Effect on Electrical Resistivity and Seebeck Coefficient of Perovskite-Type LaFeO3 Ceramics  

Microsoft Academic Search

Perovskite-type LaFe1-xCuxO3 (x = 0.10, 0.14, 0.18) solid solution is prepared with the conventional solid-state reaction technique. The electrical resistivity and the Seebeck coefficient are measured in the temperature range 473-1073K to elucidate the Cu doping effect on the thermoelectric properties of the LaFeO3. The electrical resisitivity of LaFe1-x Cux O3 shows semiconducting behavior. The temperature dependence of the electrical

Hong-Chao Wang; Chun-Lei Wang; Jia-Liang Zhang; Ming-Lei Zhao; Jian Liu; Wen-Bin Su; Na Yin; Liang-Mo Mei

2009-01-01

43

A high-performance laser energy meter based on anisotropic Seebeck effect in a strongly correlated electronic thin film  

NASA Astrophysics Data System (ADS)

We have developed a high-performance laser energy meter based on anisotropic Seebeck effect in a strongly correlated electronic (SCE) thin film. SCE thin films, typically represented by high-temperature superconductor (HTS) cuprate and colossal magnetoresistance (CMR) manganite thin films, demonstrate tremendous anisotropic Seebeck effect. In this study, a La2/3Ca1/3MnO3 thin film grown on a tilted LaAlO3 substrate is tested with the fundamental, the second, the third, and the fourth harmonics (1064, 532, 355, 266 nm, respectively) of a Q-switched Nd:YAG laser over a wide range of temperatures from room temperature to 16 K. The peak-value of the laser-induced thermoelectric voltage signal shows a good linear relationship with the laser energy per pulse in the measured wavelength and temperature ranges. The combined advantages over other commercial laser detectors such as nanosecond-order response and spectrally broad and flat response over a wide range of temperatures, in situ real-time measurement, and energy savings, make the device an ideal candidate for next-generation laser detectors and laser power/energy meters.

Zhang, G.-Y.; Zheng, H.-R.; Huang, W.-H.; Zhang, X.-Y.; Gao, D.-L.; Zhang, H.; Zhang, P.-X.; Tseng, T.-Y.; Habermeier, H.-U.; Lin, C.-T.; Cheng, H.-H.

2013-11-01

44

Thermal properties of magnons and the spin Seebeck effect in yttrium iron garnet/normal metal hybrid structures  

NASA Astrophysics Data System (ADS)

In the study of the spin Seebeck effect (SSE) in structures with a ferromagnetic insulator (FMI) in contact with a normal metal it is important to know the distributions of the temperatures of the magnon, phonon, and electron systems. Studies of the SSE in yttrium iron garnet (YIG) have relied on the thermal properties of magnons in YIG calculated with expressions valid for low temperatures. Here we present a calculation of the magnon specific heat and thermal conductivity in YIG and show that the values at room temperature are very discrepant from numbers used in the literature. With our values we calculate the temperature profiles of the magnon and phonon systems in a FMI subject to a temperature gradient in the configurations used to study the transverse and longitudinal SSE. In both cases the results are quite different from those obtained in previous studies.

Rezende, S. M.; Rodríguez-Suárez, R. L.; Lopez Ortiz, J. C.; Azevedo, A.

2014-04-01

45

High temperature Seebeck coefficient metrology  

SciTech Connect

We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

Martin, J. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Tritt, T. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634 (United States); Uher, C. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-12-15

46

Tunable Seebeck Coefficient in Monolayer Graphene Under Periodic Potentials  

NASA Astrophysics Data System (ADS)

The effect of the superlattice potential on the Seebeck coefficient tensor of graphene sheet is theoretically investigated. Strong anisotropy of the Seebeck coefficient tensor is observed. The origin of the anisotropy can be attributed to the modification of the dispersion relation in the vicinity of the Dirac point. Our finding shows that the magnitude of the Seebeck coefficient of graphene can be flexibly changed under a superlattice potential.

Ono, Shota; Zhang, Ming; Noda, Yusuke; Ohno, Kaoru

2014-06-01

47

ac current generation in chiral magnetic insulators and Skyrmion motion induced by the spin Seebeck effect.  

PubMed

We show that a temperature gradient induces an ac electric current in multiferroic insulators when the sample is embedded in a circuit. We also show that a thermal gradient can be used to move magnetic Skyrmions in insulating chiral magnets: the induced magnon flow from the hot to the cold region drives the Skyrmions in the opposite direction via a magnonic spin transfer torque. Both results are combined to compute the effect of Skyrmion motion on the ac current generation and demonstrate that Skyrmions in insulators are a promising route for spin caloritronics applications. PMID:24856718

Lin, Shi-Zeng; Batista, Cristian D; Reichhardt, Charles; Saxena, Avadh

2014-05-01

48

Joule heating-induced coexisted spin Seebeck effect and spin Hall magnetoresistance in the platinum/Y3Fe5O12 structure  

NASA Astrophysics Data System (ADS)

Spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) are observed simultaneously in the Pt/Y3Fe5O12 hybrid structure when thermal gradient is produced by Joule heating. According to their dependences on applied current, these two effects can be separated. Their dependence on heating power and magnetic field is systematically studied. With the increase of heating power, the SSE enhances linearly, whereas the SMR decreases slowly. The origin of the spin currents is further analyzed. The heating power dependences of the spin currents associated with the SSE and the SMR are found to be different.

Wang, W. X.; Wang, S. H.; Zou, L. K.; Cai, J. W.; Sun, Z. G.; Sun, J. R.

2014-11-01

49

Seebeck effect in {ital p}-CdTe: The control of electrical properties of the system Au/{ital p}-CdTe/Au by temperature gradient  

SciTech Connect

The interaction of holes with phonons was studied in {ital p}-CdTe by means of Seebeck effect and {ital I}-{ital U} characteristics measurements without and with longitudinal temperature gradient. The both phenomena are evidently influenced by optical phonon drag effect. Optical phonon drag effect obviously diminishes thermopower values, in the second case the {ital I}-{ital U} characteristics shift was observed; in our arrangement temperature difference 10 K increases or decreases the current through the sample of about 40%. The explanation of this effects observed is based on Gurevich {ital et} {ital al}. theory about the charge redistribution in mediums with nonequilibrium carriers (of two types) and phonons in semiconductors. Our experimental results could have new promising applications. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Vackova, S. [Charles University, Prague (Czech Republic)

1994-08-10

50

Nanoscale Spin Seebeck Rectifier: Controlling Thermal Spin Transport across Insulating Magnetic Junctions with Localized Spin  

NASA Astrophysics Data System (ADS)

The spin Seebeck effect is studied across a charge insulating magnetic junction, in which thermal-spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads. We show that, in contrast with bulk spin Seebeck effect, the figure of merit of such nanoscale thermal-spin conversion can be infinite, leading to the ideal Carnot efficiency in the linear response regime. We also find that in the nonlinear spin Seebeck transport regime the device possesses the asymmetric and negative differential spin Seebeck effects. In the last, the situations with leaking electron tunneling are also discussed. This nanoscale thermal spin rectifier, by tuning the junction parameters, can act as a spin Seebeck diode, spin Seebeck transistor, and spin Seebeck switch, which could have substantial implications for flexible thermal and information control in molecular spin caloritronics.

Ren, Jie; Fransson, Jonas; Zhu, Jian-Xin

2014-06-01

51

Nanoscale Spin Seebeck Rectifier: Controlling Thermal Spin Transport across Insulating Magnetic Junctions with Localized Spin  

E-print Network

The spin Seebeck effect is studied across a charge insulating magnetic junction, in which thermal-spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads. We show that, in contrast with bulk spin Seebeck effect, the figure of merit of such nanoscale thermal-spin conversion can be infinite, leading to the ideal Carnot efficiency in the linear response regime. We also find that in the nonlinear spin Seebeck transport regime, the device possesses the asymmetric and negative differential spin Seebeck effects. In the last, the situations with leaking electron tunneling are also discussed. This nanoscale thermal spin rectifier, by tuning the junction parameters, can act as a spin Seebeck diode, spin Seebeck transistor and spin Seebeck switch, which could have substantial implications for flexible thermal and information control in molecular spin caloritronics.

Jie Ren; Jonas Fransson; Jian-Xin Zhu

2013-10-15

52

Uncertainty analysis for common Seebeck and electrical resistivity measurement systems  

NASA Astrophysics Data System (ADS)

This work establishes the level of uncertainty for electrical measurements commonly made on thermoelectric samples. The analysis targets measurement systems based on the four probe method. Sources of uncertainty for both electrical resistivity and Seebeck coefficient were identified and evaluated. Included are reasonable estimates on the magnitude of each source, and cumulative propagation of error. Uncertainty for the Seebeck coefficient includes the cold-finger effect which has been quantified with thermal finite element analysis. The cold-finger effect, which is a result of parasitic heat transfer down the thermocouple probes, leads to an asymmetric over-estimation of the Seebeck coefficient. A silicon germanium thermoelectric sample has been characterized to provide an understanding of the total measurement uncertainty. The electrical resistivity was determined to contain uncertainty of ±7.0% across any measurement temperature. The Seebeck coefficient of the system is +1.0%/-13.1% at high temperature and ±1.0% near room temperature. The power factor has a combined uncertainty of +7.3%/-27.0% at high temperature and ±7.5% near room temperature. These ranges are calculated to be typical values for a general four probe Seebeck and resistivity measurement configuration.

Mackey, Jon; Dynys, Frederick; Sehirlioglu, Alp

2014-08-01

53

Uncertainty analysis for common Seebeck and electrical resistivity measurement systems.  

PubMed

This work establishes the level of uncertainty for electrical measurements commonly made on thermoelectric samples. The analysis targets measurement systems based on the four probe method. Sources of uncertainty for both electrical resistivity and Seebeck coefficient were identified and evaluated. Included are reasonable estimates on the magnitude of each source, and cumulative propagation of error. Uncertainty for the Seebeck coefficient includes the cold-finger effect which has been quantified with thermal finite element analysis. The cold-finger effect, which is a result of parasitic heat transfer down the thermocouple probes, leads to an asymmetric over-estimation of the Seebeck coefficient. A silicon germanium thermoelectric sample has been characterized to provide an understanding of the total measurement uncertainty. The electrical resistivity was determined to contain uncertainty of ±7.0% across any measurement temperature. The Seebeck coefficient of the system is +1.0%/-13.1% at high temperature and ±1.0% near room temperature. The power factor has a combined uncertainty of +7.3%/-27.0% at high temperature and ±7.5% near room temperature. These ranges are calculated to be typical values for a general four probe Seebeck and resistivity measurement configuration. PMID:25173324

Mackey, Jon; Dynys, Frederick; Sehirlioglu, Alp

2014-08-01

54

GMAG PhD Dissertation Research Award: The Planar Nernst and Seebeck Effects in Ferromagnetic Metal Films with In-Plane Thermal Gradients  

NASA Astrophysics Data System (ADS)

Recently, the spin Seebeck effect (SSE) has attracted a great deal of attention as one possible source of pure spin currents. In response to a thermal gradient (?T), the SSE is thought to produce a pure spin current detectable by measuring a transverse voltage (VT) generated by the inverse spin Hall effect. However, recent work on spin-dependent transport in thin film nanostructures supported by bulk substrates suggests that early SSE experiments may have been strongly affected by unintended ?T through the supporting substrates. They may also have been affected by thermoelectric effects generated from planar thermal gradients such as transverse thermopower, also known as the planar Nernst effect (PNE), in which a VT develops in response to a ?T applied in the plane of a film with in-plane magnetization. In this talk, we present the first results from experiments designed to probe the SSE and related effects such as the PNE and longitudinal thermopower in 20 nm thick nickel and permalloy thin films deposited on suspended Si-N platforms. In our experiments, the background thermal conduction of the 500 nm thick platforms is at least 1000x smaller than the bulk substrates used previous experiments, thus confining ?T to the plane of the film. The results exhibit the ?? angular dependence predicted by the PNE, where ? is the angle between film magnetization and thermal gradient, rather than the ? dependence expected from SSE predictions. We demonstrate that the magnetic field dependence of the PNE, anisotropic magnetoresistance, and longitudinal thermopower (?) is generated by spin-dependent scattering and present results confirming the Onsager reciprocity between ? and the Peltier coefficient. Finally, we present an upper limit for the SSE coefficient in our experiment that is at least an order of magnitude smaller than previously reported by experiments conducted using bulk substrates. I would like to thank my collaborators Barry L. Zink and Matthew R. Pufall and gratefully acknowledge support from the NSF CAREER Grant No. DMR-0847796.

Avery, Azure

2013-03-01

55

Huge Seebeck coefficients in non-aqueous electrolytes  

E-print Network

The Seeebeck coefficients of the non-aqueous electrolytes tetrabutylammonium nitrate, tetraoctylphosphonium bromide and tetradodecylammonium nitrate in 1-octanol, 1-dodecanol and ethylene-glycol are measured in a temperature range from T=30 to T=45 C. The Seebeck coefficient is generally of the order of a few hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here we report huge values of 7 mV/K at 0.1M concentration for tetrabutylammonium nitrate in 1-dodecanol. These striking results open the question of unexpectedly large kosmotrope or "structure making" effects of tetraalkylammonium ions on the structure of alcohols.

M. Bonetti; S. Nakamae; M. Roger; P. Guenoun

2011-02-11

56

Protocols for the high temperature measurement of the Seebeck coefficient in thermoelectric materials  

NASA Astrophysics Data System (ADS)

In Seebeck coefficient metrology, the present diversity in apparatus design, acquisition methodology and contact geometry has resulted in conflicting materials data that complicate the interlaboratory confirmation of reported high efficiency thermoelectric materials. To elucidate the influence of these factors in the measurement of the Seebeck coefficient at high temperature and to identify optimal metrology protocols, we measure the Seebeck coefficient as a function of contact geometry under both steady-state and transient thermal conditions of the differential method, using a custom developed apparatus capable of in situ comparative measurement. The thermal gradient formation and data acquisition methodology, under ideal conditions, have little effect on the measured Seebeck coefficient value. However, the off-axis 4-probe contact geometry, as compared to the 2-probe, results in a greater local temperature measurement error that increases with temperature. For surface temperature measurement, the dominant thermal errors arise from a parasitic heat flux that is dependent on the temperature difference between the sample and the external thermal environment, and on the various thermal resistances. Due to higher macroconstriction and contact resistance in the 4-probe arrangement, the measurement of surface temperature for this contact geometry exhibits greater error, thereby overestimating the Seebeck coefficient.

Martin, Joshua

2013-08-01

57

Description of a Sensitive Seebeck Calorimeter Used for Cold Fusion Studies  

NASA Astrophysics Data System (ADS)

A sensitive and stable Seebeck calorimeter is described and used to determine the heat of formation of PdD. This determination can be used to show that such calorimeters are sufficiently accurate to measure the LENR effect and give support to the claims.

Storms, Edmund

58

The impact of commonly used approximations on the computation of the Seebeck coefficient and mobility of polar semiconductors  

NASA Astrophysics Data System (ADS)

Seebeck coefficient modeling and measurement has important applications in direct thermal to electrical energy conversion and solid-state physics. The computations of the Seebeck coefficient and mobility of polar semiconductors in the literature often employ certain approximations, notably the relaxation time approximation (RTA) and the truncation of the Boltzmann transport equation. We study the accuracy of these approximations as a function of the effective mass, temperature, and carrier concentration using a recently developed technique for rigorous solution of the Boltzmann transport equation. We find that the approximations give rise to considerable error in the computed Seebeck coefficients of heavily doped semiconductors with a low effective mass, and that the RTA is entirely inapplicable for the accurate computation of the mobility of several important materials.

Ramu, Ashok T.; Bowers, John E.

2012-10-01

59

Fast Seebeck coefficient measurement based on dynamic method  

NASA Astrophysics Data System (ADS)

A setup based on dynamic method was developed for fast Seebeck coefficient measurement from room temperature to 473 K. Two T-type thermocouples with a response time of less than 0.1 s were used to measure the dynamic temperatures of the sample. The Cu wires of the two thermocouples served as leads for Seebeck voltage measurement. The dynamic temperature feature of the setup was characterized. Test measurements were conducted with LaCo0.9Cu0.1O3 and LaCo0.85Cu0.15O3 samples with the customized setup, and the results had a difference of ±8.4% compared with the data provided by ZEM-2 (Ulvac-Riko, Japan), which showed that the Seebeck measurement with the customized setup was reliable. In addition, the error on the Seebeck coefficient caused by the dynamic variation of temperature was discussed. The setup described in this paper has the advantage of fast Seebeck coefficient measurement with a measurement speed of about 14-23 K min-1.

Zhou, Yang; Yang, Donghua; Li, Liangliang; Li, Fu; Li, Jing-Feng

2014-05-01

60

First Principles Explanation of the Positive Seebeck Coefficient of Lithium  

NASA Astrophysics Data System (ADS)

Lithium is one of the simplest metals, with negative charge carriers and a close reproduction of free-electron dispersion. Experimentally, however, Li is one of a handful of elemental solids (along with Cu, Ag, and Au) where the sign of the Seebeck coefficient (S) is opposite to that of the carrier. This counterintuitive behavior still lacks a satisfactory interpretation. We calculate S fully from first principles, within the framework of Allen's formulation of Boltzmann transport theory. Here it is crucial to avoid the constant relaxation time approximation, which gives a sign for S which is necessarily that of the carriers. Our calculated S are in excellent agreement with experimental data, up to the melting point. In comparison with another alkali metal, Na, we demonstrate that within the simplest nontrivial model for the energy dependency of the electron lifetimes, the rapidly increasing density of states (DOS) across the Fermi energy is related to the sign of S in Li. The exceptional energy dependence of the DOS is beyond the free-electron model, as the dispersion is distorted by the Brillouin zone edge; this has a stronger effect in Li than other alkali metals. The electron lifetime dependency on energy is central, but the details of the electron-phonon interaction are found to be less important, contrary to what has been believed for several decades. Band engineering combined with the mechanism exposed here may open the door to new "ambipolar" thermoelectric materials, with a tunable sign for the thermopower even if either n- or p-type doping is impossible.

Xu, Bin; Verstraete, Matthieu J.

2014-05-01

61

Giant magnetoresistance and spin Seebeck coefficient in zigzag ?-graphyne nanoribbons.  

PubMed

We investigate the spin-dependent electric and thermoelectric properties of ferromagnetic zigzag ?-graphyne nanoribbons (Z?GNRs) using density-functional theory combined with non-equilibrium Green's function method. A giant magnetoresistance is obtained in the pristine even-width Z?GNRs and can be as high as 10(6)%. However, for the doped systems, a large magnetoresistance behavior may appear in the odd-width Z?GNRs rather than the even-width ones. This suggests that the magnetoresistance can be manipulated in a wide range by the dopants on the edges of Z?GNRs. Another interesting phenomenon is that in the B- and N-doped even-width Z?GNRs the spin Seebeck coefficient is always larger than the charge Seebeck coefficient, and a pure-spin-current thermospin device can be achieved at specific temperatures. PMID:25214422

Zhai, Ming-Xing; Wang, Xue-Feng; Vasilopoulos, P; Liu, Yu-Shen; Dong, Yao-Jun; Zhou, Liping; Jiang, Yong-Jing; You, Wen-Long

2014-10-01

62

Giant magnetoresistance and spin Seebeck coefficient in zigzag ?-graphyne nanoribbons  

NASA Astrophysics Data System (ADS)

We investigate the spin-dependent electric and thermoelectric properties of ferromagnetic zigzag ?-graphyne nanoribbons (Z?GNRs) using density-functional theory combined with non-equilibrium Green's function method. A giant magnetoresistance is obtained in the pristine even-width Z?GNRs and can be as high as 106%. However, for the doped systems, a large magnetoresistance behavior may appear in the odd-width Z?GNRs rather than the even-width ones. This suggests that the magnetoresistance can be manipulated in a wide range by the dopants on the edges of Z?GNRs. Another interesting phenomenon is that in the B- and N-doped even-width Z?GNRs the spin Seebeck coefficient is always larger than the charge Seebeck coefficient, and a pure-spin-current thermospin device can be achieved at specific temperatures.

Zhai, Ming-Xing; Wang, Xue-Feng; Vasilopoulos, P.; Liu, Yu-Shen; Dong, Yao-Jun; Zhou, Liping; Jiang, Yong-Jing; You, Wen-Long

2014-09-01

63

Spin-Seebeck like signal in ferromagnetic bulk metallic glass without platinum contacts  

NASA Astrophysics Data System (ADS)

The anomalous, ordinary, and planar Nernst effects of the ferromagnetic bulk metallic glass Co85Si5Fe3B3Mo2Ni2 are reported. The contribution of the anomalous Nernst signal when the magnetic field is oriented in the plane of the specimen is shown to be zero; yet there is an odd component to the measured signal that varies along the sample length. Even though all measurements here are made using point contacts, and no spin-sensitive Pt strips are present, the signal has similarities to the spin-Seebeck signal.

Jin, Hyungyu; Yang, Zihao; Myers, Roberto C.; Heremans, Joseph P.

2014-11-01

64

Cu-induced Seebeck peak in HMS/Si film  

NASA Astrophysics Data System (ADS)

It is well known that aluminum (Al), boron (B) and copper (Cu) are acceptor impurities with shallow- and deep-energy levels in silicon (Si), respectively. Thus, Al and B impurities with shallow-energy levels in Si are essentially completely ionized at room temperature while Cu impurities with deep-energy levels in Si at higher temperature. In this paper, Al, B and Cu co-doped Si layer is used as a barrier layer while the higher manganese silicide layer (HMS) as a well layer. The Seebeck coefficient (S) of Al and Cu modulation doped film, HMS/Si:(Al + Cu), increases sharply above 583 K, reaches a peak value of 0.300 mV/K at 683 K, and then decreases with further increasing temperature. Concomitance with the great increase in Seebeck coefficient, however, the electrical resistivity (R) is still smaller than that of only Al modulation doped film, HMS/Si:Al. The Cu-induced Seebeck peak, Smax = 0.303 mV/K at 733 K, and reduction in electrical resistivity are also observed in (B + Al + Cu) modulation doped film, Si:(B + Al + Cu)/HMS/Si:(B + Al + Cu), where B is used to reduce the electrical resistivity further. As a result, the thermoelectric power factor (PF = S2/R) is greatly enhanced and can reach 3.140 × 10-3 W/m-K2 at 733 K, which is larger than that of HMS bulk material.

Hou, Q. R.; Gu, B. F.; Chen, Y. B.

2014-08-01

65

Seebeck Coefficient of Lithium and Lithium-Tin Alloys  

NASA Astrophysics Data System (ADS)

Experiments into the viability of lithium as a first wall material in a fusion device have shown that it offers great benefits in reducing recycling of hydrogenic species at the wall, increasing energy confinement times, and gettering impurities. However, concerns have been raised about its practicality in regions of high heat fluxes, and one of the greatest is whether or not a lithium divertor concept can function at high steady state temperatures without significant evaporation of the lithium. Lithium-tin alloys might offer a solution by suppressing evaporation, but their performance in a TEMHD driven device such as the LIMIT device under development at UIUC is directly dependent on their thermoelectric properties, namely their unknown Seebeck coefficient. In support of the use of lithium-tin alloys in such a device, experiments are performed to recover the Seebeck coefficient of several different compositions of lithium-tin alloys. Experiments previously performed at the University of Illinois of the Seebeck coefficient of lithium [1] were confirmed and expanded upon by this study. Values of ranging from 12 +/-1 uV/K at 82C to 28 +/-1 uV/K at 240C were obtained.[4pt] [1] V. Surla et al. Journal of Nuclear Materials 415 (2011) 18-22.

Kirsch, L.; Fiflis, P.; Andruczyk, D.; Curreli, D.; Ruzic, D. N.

2012-10-01

66

Simultaneous Enhancement of the Electrical Conductivity and Seebeck Coefficient of PEDOT-block-PEG/SWCNTs Nanocomposites  

NASA Astrophysics Data System (ADS)

In this study, the thermoelectric (TE) performance of poly(3,4-ethylenedioxythiophene)-block-poly(ethylene glycol) (PEDOT-block-PEG), one of the most important poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives, was studied. To improve its TE performance, different mass fractions of single-walled carbon nanotubes (SWCNTs) were incorporated by physical mixing. Blending with SWCNTs resulted in simultaneous enhancement of the electrical conductivity and Seebeck coefficient of the PEDOT-block-PEG/SWCNTs nanocomposites. At 300 K, the maximum electrical conductivity was increased from 0.51 to 78.6 S/cm, and the Seebeck coefficient was increased from 5.1 to 46.3 ?V/K. The thermal conductivity of the composite films was low (0.24-0.34 W/m/K). The maximum ZT of PEDOT-block-PEG/SWCNTs nanocomposites was 1.24 × 10-2 when the SWCNTs content was 66.7 wt.%. This study suggests that constructing PEDOT-block-PEG/SWCNTs nanocomposites might be an effective way of improving the TE properties of PEDOT-block-PEG.

Jiang, Qinglin; Liu, Congcong; Zhu, Danhua; Song, Haijun; Xu, Jingkun; Shi, Hui; Mo, Daize; Wang, Zhipeng; Zhu, Zhengyou

2014-11-01

67

Seebeck Rectification Enabled by Intrinsic Thermoelectrical Coupling in Magnetic Tunneling Junctions  

NASA Astrophysics Data System (ADS)

An intrinsic thermoelectric coupling effect in the linear response regime of magnetic tunneling junctions (MTJ) is reported. In the dc response, it leads to a nonlinear correction to Ohm’s law. Dynamically, it enables a novel Seebeck rectification and second harmonic generation, which apply for a broad frequency range and can be magnetically controlled. A phenomenological model on the footing of the Onsager reciprocal relation and the principle of energy conservation explains very well the experimental results obtained from both dc and frequency-dependent transport measurements performed up to GHz frequencies. Our work refines previous understanding of magnetotransport and microwave rectification in MTJs. It forms a new foundation for utilizing spin caloritronics in high-frequency applications.

Zhang, Z. H.; Gui, Y. S.; Fu, L.; Fan, X. L.; Cao, J. W.; Xue, D. S.; Freitas, P. P.; Houssameddine, D.; Hemour, S.; Wu, K.; Hu, C.-M.

2012-07-01

68

A unified physical model of Seebeck coefficient in amorphous oxide semiconductor thin-film transistors  

NASA Astrophysics Data System (ADS)

A unified physical model for Seebeck coefficient was presented based on the multiple-trapping and release theory for amorphous oxide semiconductor thin-film transistors. According to the proposed model, the Seebeck coefficient is attributed to the Fermi-Dirac statistics combined with the energy dependent trap density of states and the gate-voltage dependence of the quasi-Fermi level. The simulation results show that the gate voltage, energy disorder, and temperature dependent Seebeck coefficient can be well described. The calculation also shows a good agreement with the experimental data in amorphous In-Ga-Zn-O thin-film transistor.

Lu, Nianduan; Li, Ling; Sun, Pengxiao; Banerjee, Writam; Liu, Ming

2014-09-01

69

Studies on Seebeck Coefficient of Individual Bismuth Telluride Nanotube  

NASA Astrophysics Data System (ADS)

We have studied on Seebeck coefficient (S) of freestanding individual Bismuth Telluride nanotubes using micro-fabricated thermoelectric workbench at the temperatures from 300 K to 25 K. The thermoelectric workbench is composed of three main elements: heater, thermocouple, and platinum pad. A polysilicon-gold thermocouple accurately measures the temperature, arising from the heat generated at the tips of the test sites from the polysilicon heater located 2 ?m apart from the thermocouple. Platinum pads placed on top of the heater and thermocouple structures and electrically isolated from these constitute S measurement circuit. IPA solution containing Bi2Te3 nanotubes was drop-cast on the workbench and the Ebeam Induced Deposition of platinum was used to improve the electrical and thermal contacts between nanotube and platinum pads. The inner and outer diameter of nanotube is 50 nm and 70 nm, respectively. The sign of obtained S was positive which is indicating the nanotube is p-type. And the magnitude was increased compared to the bulk and nanowire types. The measured S (364 ?V/K) of nanotube at T = 300 K is 1.65 times larger than that (220 ?V/K) of bulk and 1.4 times larger than the previously reported value (260 ?V/K) of nanowire.

Kim, Duksoo; Du, Renzhong; Yin, Yuewei; Dong, Sining; Li, Xiaoguang; Li, Qi; Tadigadapa, Srinivas

2013-03-01

70

Dependence of Seebeck coefficient on a load resistance and energy conversion efficiency in a thermoelectric composite  

SciTech Connect

The thermo-emf {delta}V and current {delta}I generated by imposing the alternating temperature gradients (ATG) at a period of T and the steady temperature gradient (STG) on a thermoelectric (TE) composite were measured as a function of t, where t is the lapsed time and T was varied from 60 to or {infinity} s. The STG and ATG were produced by imposing steadily and alternatively a source voltage V in the range from 1.0 to 4.0 V on two Peltier modules sandwiching a composite. {delta}T, {delta}V, {delta}I and V{sub P} oscillate at a period T and their waveforms vary significantly with a change of T, where {delta}V and V{sub P} are the voltage drops in a load resistance R{sub L} and in resistance R{sub P} of two modules. The resultant Seebeck coefficient |{alpha}| = |{delta}V|/{delta}T of a composite under the STG was found to be expressed as |{alpha}| = |{alpha}{sub 0}|(1 - R{sub comp}/R{sub T}), where R{sub T} is the total resistance of a circuit for measuring the output signals and R{sub comp} is the resistance of a composite. The effective generating power {delta}W{sub eff} has a local maximum at T = 960 s for the p-type composite and at T = 480 s for the n-type one. The maximum energy conversion efficiency {eta} of the p- and n-type composites under the ATG produced by imposing a voltage of 4.0 V at an optimum period were 0.22 and 0.23% at {delta}T{sub eff} = 50 K, respectively, which are 42 and 43% higher than those at {delta}T = 42 K under the STG. These maximum {eta} for a TE composite sandwiched between two Peltier modules, were found to be expressed theoretically in terms of R{sub P}, R{sub T}, R{sub L}, {alpha}{sub P} and {alpha}, where {alpha}{sub P} and {alpha} are the resultant Seebeck coefficients of Peltier modules and a TE composite.

Yamashita, Osamu [Materials Science Co. Ltd., 5-5-44 Minamikasugaoka, Ibaraki, Osaka 567-0046 (Japan)], E-mail: yamashio567@yahoo.co.jp; Odahara, Hirotaka [Advanced Materials Co. Ltd., 4-6-10 Kizuri, Higashiosaka, Osaka 577-0827 (Japan); Ochi, Takahiro; Satou, Kouji [Faculty of Engineering, Ehime University, Bunkyocho, Matsuyama 790-8577 (Japan)

2007-10-02

71

Macro and Micro-Scale Features of Thermoelectric PbTe (Br, Na) Systems: Micro-FTIR Spectroscopy, Micro-Seebeck Measurements, and SEM/EDX Observations  

NASA Astrophysics Data System (ADS)

In this work, n-type and p-type PbTe doped with Br and Na, respectively, were thoroughly examined to determine the effect of the dopant on microstructure. Macro and micro homogeneity of the samples were studied by means of micro-Fourier-transform infrared (micro-FTIR) spectroscopy, micro-Seebeck measurements, and scanning electron microscopy with energy-dispersive x-ray analysis (SEM/EDX). SEM/EDX observations showed the samples were not single-phase materials—second phases were created by inclusions that disturbed the coherence of the matrix and, subsequently, drastically affected the Seebeck coefficient. In a micro-scale study, local variations of sodium content were detected in Na-doped samples; in Br-doped samples a second, PbBr2, phase was observed in the PbTe matrix. A direct effect of matrix dopant on Seebeck coefficient and plasmon frequency for the Br-doped and Na-doped samples was observed by use of the three complementary techniques.

Stefanaki, E. C.; Polymeris, G. S.; Nikolic, P. M.; Papageorgiou, Ch.; Pavlidou, E.; Hatzikraniotis, E.; Kyratsi, Th.; Paraskevopoulos, K. M.

2014-10-01

72

Profiling the Local Seebeck Coefficient with Nanometer Resolution Using Scanning Thermoelectric Microscopy (SThEM)  

NASA Astrophysics Data System (ADS)

Thermoelectric (TE) devices offer a method of recovering waste heat through solid state conversion of heat to electricity. Nanostructured thermoelectric materials may provide the key to increased efficiencies, which are sensitive to the Seebeck coefficients (S) However, traditional bulk measurement techniques can only provide a spatially averaged measurement of S over the whole sample, which can hardly investigate the effects of nanostructures on S on the nanoscale. A novel technique known as scanning thermoelectric microscopy (SThEM) has recently been developed to measure induced thermal voltages with nanometer resolution In SThEM, an unheated scanning tunneling microscopy tip acts as a high-resolution voltmeter probe to measure the thermally-induced voltage, V, in a heated sample. Here we present a local S measurement using SThEM across an InGaAs P-N junction. The thermovoltage shows an abrupt change of sign within 10 nanometers, which reveals nanometer spatial resolution. We will discuss local S measurements of AlAs/GaAs superlattices (SLs) with various SL periods and compare the local S with scanning tunneling spectroscopy measurements, which will reveal how local electronic states influence thermoelectric properties.

Lin, Yen-Hsiang; Walrath, Jenna; Goldman, Rachel

2013-03-01

73

Measurement system of the Seebeck coefficient or of the electrical resistivity at high temperature.  

PubMed

A high temperature Seebeck coefficient or electrical resistivity apparatus has been designed and fabricated to measure sample with typical size ~10 × 1 × 1 mm(3). It can measure both transport properties from 300 K to 1000 K in argon atmosphere. The sample lies transversely on top of two metallic half-cylinders, which contain heating cartridges and allow temperature and thermal gradient control and reversal. The temperature gradient is measured by two type N thermocouples pressed against the upper surface of the sample. The key feature of this apparatus is the disk-shaped junction of each type N thermocouple which strongly improves the thermal contact with the sample. The Seebeck coefficient is obtained by averaging over two measured values with opposite thermal gradient directions (~±2 K). For the resistivity measurements, the temperature is stabilized and the temperature gradient is actively reduced below 0.2 K to make negligible any spurious thermal voltage. Uncertainties of ~3% for the Seebeck coefficient and 1% for the resistivity were obtained on Ni samples. The Seebeck coefficient and resistivity have also been measured on a skutterudite sample as small as ~7 × 1.5 × 0.5 mm(3) with very good agreement with literature. PMID:24182159

Rouleau, O; Alleno, E

2013-10-01

74

Development and application of an instrument for spatially resolved Seebeck coefficient measurements  

NASA Astrophysics Data System (ADS)

The Seebeck coefficient is a key indicator of the majority carrier type (electrons or holes) in a material. The recent trend toward the development of combinatorial materials research methods has necessitated the development of a new high-throughput approach to measuring the Seebeck coefficient at spatially distinct points across any sample. The overall strategy of the high-throughput experiments is to quickly identify the region of interest on the sample at some expense of accuracy, and then study this region by more conventional techniques. The instrument for spatially resolved Seebeck coefficient measurements reported here relies on establishing a temperature difference across the entire compositionally graded thin-film and consecutive mapping of the resulting voltage as a function of position, which facilitates the temperature-dependent measurements up to 400 °C. The results of the designed instrument are verified at ambient temperature to be repeatable over 10 identical samples and accurate to within 10% versus conventional Seebeck coefficient measurements over the -100 to +150 ?V/K range using both n-type and p-type conductive oxides as test cases. The developed instrument was used to determine the sign of electrical carriers of compositionally graded Zn-Co-O and Ni-Co-O libraries prepared by combinatorial sputtering. As a result of this study, both cobalt-based materials were determined to have p-type conduction over a broad single-phase region of chemical compositions and small variation of the Seebeck coefficient over the entire investigated range of compositions and temperature.

Zakutayev, Andriy; Luciano, Frank J.; Bollinger, Vincent P.; Sigdel, Ajaya K.; Ndione, Paul F.; Perkins, John D.; Berry, Joseph J.; Parilla, Philip A.; Ginley, David S.

2013-05-01

75

Enhancement of Seebeck coefficient for SrO(SrTiO3)2 by Sm substitution: Crystal symmetry restoration of distorted TiO6 octahedra  

NASA Astrophysics Data System (ADS)

We found that Sm3+ substitution in SrO(SrTiO3)2 is effective in improving the Seebeck coefficient (S). The ?S? value increases notably with temperature, benefiting from an enhancement of the density of states (DOS) effective mass md* from ˜3m0 (300K)to˜7.5m0 (1000K), due to an improvement of the local symmetry of TiO6 octahedra, enhancing the degeneracy in the Ti 3d orbitals, which form the conduction band (CB), and also to an accompanying lattice expansion, which gives rise to a higher DOS at the bottom of the CB and, consequently, a larger md*.

Wang, Yifeng; Lee, Kyu Hyoung; Hyuga, Hideki; Kita, Hideki; Inaba, Katsuhiko; Ohta, Hiromichi; Koumoto, Kunihito

2007-12-01

76

Local Seebeck coefficient near the boundary in touching Cu/Bi-Te/Cu composites  

NASA Astrophysics Data System (ADS)

The thermo-emf ?V and temperature difference ?T across the boundary were measured as a function of r for the touching p- and n-type Cu/Bi-Te/Cu composites composed of a combination of tBi-Te=2.0 mm and tCu=0.3 mm, where ?T is produced by imposing a constant voltage of 1.7 V on two Peltier modules connected in series and r is the distance from the boundary that corresponds to the interval s between two thermocouples. The resultant Seebeck coefficient ? across the boundary was obtained from the relation ?=?V/?T. As a result, the resultant ? of the touching p- and n-type composites have surprisingly great local maximum values of 1330 and -1140 ?V/K at r?0.03 mm, respectively, and decreased rapidly with an increase of r to approach the Seebeck coefficients of the intrinsic Bi-Te compounds. The resultant maximum ? of the touching p- and n-type Cu/Bi-Te/Cu composites are approximately 5.4 and 5.5 times higher in absolute value than those of the intrinsic Bi-Te compounds, respectively. It was thus clarified for the first time that the local Seebeck coefficient is enhanced most strongly in the Bi-Te region where there is an approximately 30-?m distance from the boundary, not at the boundary between Bi-Te compounds and copper.

Yamashita, O.; Odahara, H.

2007-06-01

77

Seebeck Coefficient and Optical Studies of Cadmium Doped CuInS2 Single Crystal  

NASA Astrophysics Data System (ADS)

Full Text PDF Single crystals of CuInS2 were successfully grown by chemical vapor transport technique using iodine as transporting agent. The as grown chemical vapor transport CuInS2 single crystals were found to have large resistivity. To decrease the resistivity of the crystals they were doped with three different cadmium concentrations. Seebeck coefficient variation with temperature is measured for all the three doped samples. Optical bandgaps were determined for these three doped samples using optical absorption spectra. The obtained results are discussed in detail.

Chaki, S. H.

2009-08-01

78

Improvement of Thermoelectric Properties of PEDOT/PSS Films by Addition of Gold Nanoparticles: Enhancement of Seebeck Coefficient  

NASA Astrophysics Data System (ADS)

Thermoelectric properties of hybrid films composed of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) and gold nanoparticles (AuNPs) stabilized with 3-mercaptopropinoic acid (Au-MPA NPs) and 6-mercaptohexanoic acid (Au-MHA NPs) were investigated. Several factors such as the size and content of the AuNPs, and the chain length of the NP stabilizer were found to influence the thermoelectric properties of the hybrid film. The Seebeck coefficient can be raised by varying the size of the Au-MPA NPs or the content of Au-MHA NPs. The enhancement in the Seebeck coefficient is suggested to be a result of reduced carrier concentration due to the increased number of AuNPs. This could be the first report on the fact that AuNPs enhance the Seebeck coefficient in PEDOT/PSS hybrid films.

Toshima, Naoki; Jiravanichanun, Nattha

2013-07-01

79

Seebeck Coefficient of Manganese Oxide Nanoparticles as a Function of Ohmic Resistance  

NASA Astrophysics Data System (ADS)

Due to the ever increasing energy demand and growing global concern over the environmental impact of CO2 emissions, there is an urging need to seek solutions to transit from fossil fuels to sustainable energy. Thermoelectric (TE) materials show great promise for converting waste heat energy into electricity. TE systems have many unique advantages such as silent operationality, time reliability, and dimensional scalability. Most recently, researchers Song et al. [1] found that MnO2 nanoparticles show a giant Seebeck coefficient of S = 20 mV/K, which is100 times higher than bismuth telluride, one of the best TE materials. Song et al.[1] concluded the paper claiming that the giant S is related to the surface density of the electronic states (DOS). However, they provided very little information about the S as a function of Ohmic resistance [R] for different nano particle sizes which can give information about the DOS. Our preliminary results show that there is a sudden increase of S from 0.33-0.63 mV/K as R increases from 80-110 Ohms. This transition has never been seen before and it can give clues as to the existence of the Giant S observed in this material.[4pt] [1] F. Song, L. Wu and S. Liang, Giant Seebeck coefficient thermoelectric device of MnO2 powder, Nano. 23, 085401 (2012).

Francis, Nicholas; Hedden, Morgan; Constantin, Costel

2013-03-01

80

Thermal spin injection and accumulation in CoFe/MgO tunnel contacts to n-type Si through Seebeck spin tunneling  

NASA Astrophysics Data System (ADS)

We report the thermal spin injection and accumulation in crystalline CoFe/MgO tunnel contacts to n-type Si through Seebeck spin tunneling (SST). With the Joule heating (laser heating) of Si (CoFe), the thermally induced spin accumulation is detected by means of the Hanle effect for both polarities of the temperature gradient across the tunnel contact. The magnitude of the thermal spin signal scales linearly with the heating power, and its sign is reversed as we invert the temperature gradient, demonstrating the major features of SST and thermal spin accumulation. Based on a quantitative comparison of the thermal and electrical spin signals, the thermal spin injection through SST is suggested as an effective route to inject the spin accumulation.

Jeon, Kun-Rok; Min, Byoung-Chul; Park, Seung-Young; Lee, Kyeong-Dong; Song, Hyon-Seok; Park, Youn-Ho; Shin, Sung-Chul

2013-09-01

81

Giant thermoelectric Seebeck coefficient of a two-dimensional electron gas in SrTiO3  

Microsoft Academic Search

Enhancement of the Seebeck coefficient (S) without reducing the electrical conductivity (sigma) is essential to realize practical thermoelectric materials exhibiting a dimensionless figure of merit (ZT=S2.sigma.T.kappa-1) exceeding 2, where T is the absolute temperature and kappa is the thermal conductivity. Here, we demonstrate that a high-density two-dimensional electron gas (2DEG) confined within a unit cell layer thickness in SrTiO3 yields

Hiromichi Ohta; Sungwng Kim; Yoriko Mune; Teruyasu Mizoguchi; Kenji Nomura; Shingo Ohta; Takashi Nomura; Yuki Nakanishi; Yuichi Ikuhara; Masahiro Hirano; Hideo Hosono; Kunihito Koumoto

2007-01-01

82

The Seebeck Coefficient in Oxygen Enriched La2NiO4  

NASA Astrophysics Data System (ADS)

Oxide-based devices show promise for themoelectric applications due to their chemical stability and straightforward fabrication. The La2NiO4+? system has been predicted to show an increased thermopower coupled with an increased electrical conductivity around ?=0.05 [Pardo et al. PRB 86, 165114 (2012)] that could lead to a large thermoelectric figure of merit (ZT). We investigate the suitability of lanthanum nickelate as a candidate material for high-ZT devices through a systematic study of oxygenated thin films grown by pulsed laser deposition. We report the electrical conductivity, Seebeck coefficient, and structural morphology of La2NiO4 grown in a range of oxidizing atmospheres and discuss their implications for controlled engineering of thermoelectric properties. We have explored the possibility of gate-tuning these systems in order to fabricate single-oxide based devices. This work was supported by the Ministerio de Ciencia e Innovación (Spain), grant MAT2010-16157, and the European Research Council, grant ERC-2010-StG 259082 2D THERMS.

Bach, Paul; Leboran, Victor; Rivadulla, Francisco

2013-03-01

83

Thermal conductivity and Seebeck coefficients of icosahedral boron arsenide films on silicon carbide  

SciTech Connect

The thermal conductivity of icosahedral boron arsenide (B{sub 12}As{sub 2}) films grown on (0001) 6H-SiC substrates by chemical vapor deposition was studied by the 3{omega} technique. The room temperature thermal conductivity decreased from 27.0 to 15.3 W/m K as the growth temperature was decreased from 1450 to 1275 deg. C. This is mainly attributed to the differences in the impurity concentration and microstructure, determined from secondary ion mass spectrometry and high resolution transmission electron microscopy, respectively. Callaway's theory was applied to calculate the temperature-dependent thermal conductivity, and the results are in good agreement with the experimental data. Seebeck coefficients were determined as 107 {mu}V/K and 136 {mu}V/K for samples grown at 1350 deg. C with AsH{sub 3}/B{sub 2}H{sub 6} flow ratio equals to 1:1 and 3:5, respectively.

Gong, Y.; Kuball, M. [H.H. Wills Physics Laboratory, Centre for Device Thermography and Reliability (CDTR), University of Bristol, Bristol BS8 1TL (United Kingdom); Zhang, Y.; Dudley, M. [Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794-2275 (United States); Zhang, Y.; Edgar, J. H. [Department of Chemical Engineering, Kansas State University, Manhattan, Kansas 66506 (United States); Heard, P. J. [Interface Analysis Centre, University of Bristol, Bristol BS2 8BS (United Kingdom)

2010-10-15

84

Evaluation of Seebeck coefficients in n- and p-type silicon nanowires fabricated by complementary metal-oxide-semiconductor technology.  

PubMed

Silicon-based thermoelectric nanowires were fabricated by using complementary metal-oxide-semiconductor (CMOS) technology. 50 nm width n- and p-type silicon nanowires (SiNWs) were manufactured using a conventional photolithography method on 8 inch silicon wafer. For the evaluation of the Seebeck coefficients of the silicon nanowires, heater and temperature sensor embedded test patterns were fabricated. Moreover, for the elimination of electrical and thermal contact resistance issues, the SiNWs, heater and temperature sensors were fabricated monolithically using a CMOS process. For validation of the temperature measurement by an electrical method, scanning thermal microscopy analysis was carried out. The highest Seebeck coefficients were - 169.97 ?V K(-1) and 152.82 ?V K(-1) and the highest power factors were 2.77 mW m(-1) K(-2) and 0.65 mW m(-1) K(-2) for n- and p-type SiNWs, respectively, in the temperature range from 200 to 300 K. The larger power factor value for n-type SiNW was due to the higher electrical conductivity. The total Seebeck coefficient and total power factor for the n- and p-leg unit device were 157.66 ?V K(-1) and 9.30 mW m(-1) K(-2) at 300 K, respectively. PMID:22995969

Hyun, Younghoon; Park, Youngsam; Choi, Wonchul; Kim, Jaehyeon; Zyung, Taehyoung; Jang, Moongyu

2012-10-12

85

Erratum to ``Seebeck effect in carbon fiber reinforced cement''$ Sihai Wen, D.D.L. Chung*  

E-print Network

fume; L: latex. a % by mass of cement. b From Ref. 1. Table 2 of Paper 2 Cement and Concrete Research 0.05 + 2.72 F 0.05 (ii) Silica fume + 0.31 F 0.02 + 2.65 F 0.02 + 0.36 F 0.03 + 2.70 F 0.03 (iii) 0.5% fibers + silica fume + 1.45 F 0.09 + 3.79 F 0.09 + 1.45 F 0.09 + 3.79 F 0.09 (iv) 1.0% fibers + silica

Chung, Deborah D.L.

86

Seebeck and figure of merit enhancement in nanostructured antimony telluride by antisite defect suppression through sulfur doping.  

PubMed

Antimony telluride has a low thermoelectric figure of merit (ZT < ?0.3) because of a low Seebeck coefficient ? arising from high degenerate hole concentrations generated by antimony antisite defects. Here, we mitigate this key problem by suppressing antisite defect formation using subatomic percent sulfur doping. The resultant 10-25% higher ? in bulk nanocrystalline antimony telluride leads to ZT ? 0.95 at 423 K, which is superior to the best non-nanostructured antimony telluride alloys. Density functional theory calculations indicate that sulfur increases the antisite formation activation energy and presage further improvements leading to ZT ? 2 through optimized doping. Our findings are promising for designing novel thermoelectric materials for refrigeration, waste heat recovery, and solar thermal applications. PMID:22891784

Mehta, Rutvik J; Zhang, Yanliang; Zhu, Hong; Parker, David S; Belley, Matthew; Singh, David J; Ramprasad, Ramamurthy; Borca-Tasciuc, Theodorian; Ramanath, Ganpati

2012-09-12

87

Transport Properties of Bulk Thermoelectrics An International Round-Robin Study, Part I: Seebeck Coefficient and Electrical Resistivity  

SciTech Connect

Recent research and development of high temperature thermoelectric materials has demonstrated great potential of converting automobile exhaust heat directly into electricity. Thermoelectrics based on classic bismuth telluride have also started to impact the automotive industry by enhancing air conditioning efficiency and integrated cabin climate control. In addition to engineering challenges of making reliable and efficient devices to withstand thermal and mechanical cycling, the remaining issues in thermoelectric power generation and refrigeration are mostly materials related. The figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In the meantime, the thermoelectric community could greatly benefit from the development of international test standards, improved test methods and better characterization tools. Internationally, thermoelectrics have been recognized by many countries as an important area for improving energy efficiency. The International Energy Agency (IEA) group under the implementing agreement for Advanced Materials for Transportation (AMT) identified thermoelectric materials as an important area in 2009. This paper is Part I of the international round-robin testing of transport properties of bulk thermoelectrics. The main focuses in Part I are on two electronic transport properties: Seebeck coefficient and electrical resistivity.

Wang, Hsin [ORNL; Porter, Wallace D [ORNL; Bottner, Harold [Fraunhofer-Institute, Freiburg, Germany; Konig, Jan [Fraunhofer-Institute, Freiburg, Germany; Chen, Lidong [Chinese Academy of Sciences; Bai, Shengqiang [Chinese Academy of Sciences; Tritt, Terry M. [Clemson University; Mayolett, Alex [Corning, Inc; Senawiratne, Jayantha [Corning, Inc; Smith, Charlene [Corning, Inc; Harris, Fred [ZT-Plus; Gilbert, Partricia [Marlow Industries, Inc; Sharp, Jeff [Marlow Industries, Inc; Lo, Jason [CANMET - Materials Technology Laboratory, Natural Resources of Canada; Keinke, Holger [University of Waterloo, Canada; Kiss, Laszlo I. [University of Quebec at Chicoutimi

2013-01-01

88

Thermal conductivity and Seebeck coefficient of 12CaO?7Al2O3 electride with a cage structure  

NASA Astrophysics Data System (ADS)

Thermal conductivity (?) and Seebeck coefficient (?) of electron-doped light-metal oxide 12CaO?7Al2O3 (C12A7 electride) with a subnanometer-sized cage structure are reported on single crystals with various electron concentrations (Ne) . The semiconducting C12A7 electride exhibits n -type conduction with the highest ? value of -100?VK-1 at 300 K. The ? exhibits an amorphouslike T2 dependence at low temperatures and varies between 2.3 and 4.5Wm-1K-1 at 300 K. This is an order-of-magnitude lower than that of the constituents, CaO (15Wm-1K-1) and Al2O3 (30Wm-1K-1) . These properties are attributed to the cage structure, suggesting that the semiconducting electride should be regarded as a phonon glass and electron crystal material. The thermoelectric performance of electrides evaluated by a dimensionless figure of merit (ZT) shows an optimized value of 2×10-3 at 300 K for the semiconducting electride with Ne of 5×1020cm-3 .

Kim, Sung Wng; Tarumi, Ryuichi; Iwasaki, Hideo; Ohta, Hiromichi; Hirano, Masahiro; Hosono, Hideo

2009-08-01

89

Valley photothermoelectric effects in transition-metal dichalcogenides  

NASA Astrophysics Data System (ADS)

We theoretically investigate photothermoelectric effects, i.e., the photoenabled versions of the Seebeck and Nernst effects in monolayer transition metal dichalcogenides (TMDCs) using semiclassical transport theory. We find that monolayer TMDCs subjected to circular polarized light show anomalous thermoelectric properties as a result of strong spin-orbit interaction and broken inversion symmetry. The Seebeck coefficient for photogenerated carriers is relatively large and changes its sign at a critical carrier density. In addition, a nontrivial photo-Nernst effect emerges in the absence of an external magnetic field or magnetic moments.

Konabe, Satoru; Yamamoto, Takahiro

2014-08-01

90

Hall, Seebeck, and Nernst Coefficients of Underdoped HgBa2CuO4+?: Fermi-Surface Reconstruction in an Archetypal Cuprate Superconductor  

Charge-density-wave order has been observed in cuprate superconductors whose crystal structure breaks the square symmetry of the CuO2 planes, such as orthorhombic YBa2Cu3Oy (YBCO), but not so far in cuprates that preserve that symmetry, such as tetragonal HgBa2CuO4+? (Hg1201). We have measured the Hall (RH), Seebeck (S), and Nernst (?) coefficients of underdoped Hg1201 in magnetic fields large enough to suppress superconductivity. The high-field RH(T) and S(T) are found to drop with decreasing temperature and become negative, as also observed in YBCO at comparable doping. In YBCO, the negative RH and S are signatures of a small electron pocket caused by Fermi-surface reconstruction, attributed to charge-density-wave modulations observed in the same range of doping and temperature. We deduce that a similar Fermi-surface reconstruction takes place in Hg1201, evidence that density-wave order exists in this material. A striking similarity is also found in the normal-state Nernst coefficient ?(T), further supporting this interpretation. Given the model nature of Hg1201, Fermi-surface reconstruction appears to be common to all hole-doped cuprates, suggesting that density-wave order is a fundamental property of these materials.

Doiron-Leyraud, Nicolas; Lepault, S.; Cyr-Choinière, O.; Vignolle, B.; Grissonnanche, G.; Laliberté, F.; Chang, J.; Bariši?, N.; Chan, M. K.; Ji, L.; Zhao, X.; Li, Y.; Greven, M.; Proust, C.; Taillefer, Louis

2013-06-01

91

Seebeck coefficient in organic semiconductors  

E-print Network

demonstrated examples of such applications are large area bendy displays based on organic light emitting diodes (OLEDs) such as LG’s 77-inch Ultra HD curved OLED TV [23] and flexible electronic skin meshed with embedded sensors and actuators [24]. 1.3 Organic...

Venkateshvaran, Deepak

2014-07-01

92

The Seebeck coefficient of iodine  

E-print Network

stals Nitrogen gas was used to dry the crystals. To wet them, the gas was first bubbled through water. Wet crystals were found to attach themselves to the upper platinum foil (hot junction) and to have a lower resistance than dry crystals... erature Variation and Measurement The temperature of the sample was varied by blowing air through two tubes in thermal, but not electrical contact with the copper rods. The stability of the cool junction was found to be below I/2 K' for temperatures...

Perez-Fernandez, Domingo Miguel

2012-06-07

93

Thermoelectric Effect across the Metal-Insulator Domain Walls in VO2  

E-print Network

Thermoelectric Effect across the Metal-Insulator Domain Walls in VO2 Microbeams J. Cao,,, W. Fan-performance thermoelectric materials are currently one of the focuses in materials research for energy conversion technologies.1-4 A good thermoelectric material should have a relatively high thermopower (Seebeck coefficient

Wu, Junqiao

94

Analysis of Residual Acceleration Effects on Transport and Segregation During Directional Solidification of Tin-Bismuth in the MEPHISTO Furnace Facility  

NASA Technical Reports Server (NTRS)

The objective of this work is to approach the problem of determining the transport conditions (and effects of residual acceleration) during the plane-front directional solidification of a tin-bismuth alloy under low gravity conditions. The work involves using a combination of 2- and 3-D numerical models, scaling analyses, ID models and the results of ground-based and low-gravity experiments. The latter are to be conducted during the MEPHISTO experiment scheduled for USMP-3 in early 1996. The models will be used to predict the response of the transport conditions and consequent solute segregation in directionally solidifying tin-bismuth melt. Real-time Seebeck voltage variations across a Sn-Bi melt during directional solidification in MEPHISTO on USMP-1 show a distinct variation which can be correlated with thruster firings. The Seebeck voltage measurement is related to the response of the instantaneous average melt composition at the melt-solid interface. This allows a direct comparison of numerical simulations with the Seebeck signals obtained on USMP-1. The effects of such accelerations on composition for a directionally solidifying Sn-Bi alloy have been simulated numerically. USMP-1 acceleration data was used to assist in our choice of acceleration magnitude and orientation. The results show good agreement with experimental observations. The USMP-3 experiments took place earlier this year (February 22 through March 6). There were several differences between the USMP-3 experiments as compared to USMP-1. Firstly a more concentrated alloy was solidified and, secondly, Primary Reaction Control System thruster burns were requested at particular times during four separate growth runs. This allowed us to monitor the response Seebeck response under well-characterized growth conditions. In addition, we carried out simulations during the experiment in order to interpret the Seebeck signal. Preliminary results are described here.

Alexander J. Iwan D. (Principal Investigator)

1996-01-01

95

Effect of aluminum on the thermoelectric properties of nanostructured PbTe.  

PubMed

In the present work, the effect of aluminum (Al) on the thermoelectric properties of PbTe is studied. Aluminum doped PbTe samples, fabricated by a ball milling and hot pressing, have Seebeck coefficients between -100 and -200 ?V K-1 and electrical conductivities of (3.6-18) × 104 S m-1 at room temperature, which means that Al is an effective donor in PbTe. The first principle calculations clearly show an increase of the density of states close to the Fermi level in the conduction band due to Al doping, which averages up the energy and effective mass of electrons, resulting in enhancement of the Seebeck coefficient. The maximum figure-of-merit ZT of 1.2 is reached at 770 K in the Al0.03PbTe sample. PMID:23912680

Zhang, Qinyong; Yang, Siqi; Zhang, Qian; Chen, Shuo; Liu, Weishu; Wang, Hui; Tian, Zhiting; Broido, David; Chen, Gang; Ren, Zhifeng

2013-08-30

96

On the Quantum Hall Effect in mono(bi)-layer graphene  

NASA Astrophysics Data System (ADS)

Based on a thermodynamic approach, we have calculated the specific resistivity of mono(bi)-layer graphene assumed dissipationless in quantizing magnetic field. The resistivity arises from combination of Peltier and Seebeck effects. The current I causes heating (cooling) at the first (second) sample contacts, due to the Peltier effect. The voltage measured across the sample is equal to the Seebeck thermoemf, and thus provides finite resistivity as I?0. The resistivity is a universal function of the magnetic field, e-h plasma density and temperature, expressed in fundamental units h/e2. At fixed magnetic field the magneto-transport problem is resolved in the vicinity of the Dirac point taking into account the splitting of zeroth Landau level. For mono(bi)- layer graphene the B-dependent splitting of zeroth Landau level is recovered from experimental data.

Cheremisin, M. V.

2014-11-01

97

Effect of Doping on Thermoelectric Properties of Delafossite-Type Oxide CuCrO2  

Microsoft Academic Search

We have studied the effects of doping on the high-temperature thermoelectric properties of the delafossite-type oxide CuCrO2. The single or double doping of divalent cations for Cr3+ ions was carried out to introduce hole carriers. For the first step, we measured the electrical conductivity sigma and Seebeck coefficient S of single-doped samples, and calculated the power factor P=sigma S2. Mg-,

Kei Hayashi; Ken-ichi Sato; Tomohiro Nozaki; Tsuyoshi Kajitani

2008-01-01

98

Seebeck nanoantennas for solar energy harvesting  

NASA Astrophysics Data System (ADS)

We propose a mid-infrared device based on thermocouple optical antennas for light sensing and energy harvesting applications. We numerically demonstrate that antennas are able to generate low-power dc signals by beneficing of the thermoelectric properties of the metals that constitute them. We theoretically evaluate the optical-to-electrical conversion efficiency for harvesting applications and finally discuss strategies to increase its performance. Thermocouple optical antennas therefore open the route toward the design of photovoltaic devices.

Briones, E.; Briones, J.; Cuadrado, A.; Martinez-Anton, J. C.; McMurtry, S.; Hehn, M.; Montaigne, F.; Alda, J.; Gonzalez, F. J.

2014-09-01

99

Effect of Ag or Sb addition on the thermoelectric properties of PbTe  

NASA Astrophysics Data System (ADS)

In this study, the effect of Ag or Sb addition on the thermoelectric properties of PbTe including the Seebeck coefficient, the electrical resistivity, and the thermal conductivity, was studied in the temperature range from 323 to 723 K. The major carriers in the Ag-doped and the Sb-doped PbTe are holes and electrons, respectively. A degenerate semiconductor behavior in the electrical transport properties was observed in the Ag-doped, whereas the semi-metallic in the Sb-doped. It was suggested from the results of the Hall effect measurement and the Seebeck coefficient that the effective mass was significantly altered by the Sb-doping. The maximum dimensionless figure of merit, ZT, of Pb1-xAgxTe and Pb1-xSbxTe (x=0.1) alloys showed 0.27 and 0.62 at 723 K, respectively. Based on the analysis of the Seebeck coefficient of the Ag or the Sb-doped PbTe, the interaction between Ag and Sb in PbTe, as expected in the AgPbmSbTem+2 (LAST-m), may be supposed.

Dow, H. S.; Oh, M. W.; Kim, B. S.; Park, S. D.; Min, B. K.; Lee, H. W.; Wee, D. M.

2010-12-01

100

Application of the Transverse Thermoelectric Effects  

NASA Astrophysics Data System (ADS)

Most thermoelectric applications make use of the longitudinal Seebeck and Peltier effects. However, it is possible to produce thermoelectric effects in which the electrical and thermal flows are perpendicular to one another. This has certain practical advantages; for example, it makes possible the realization of an infinite-staged cascade refrigerator using a single piece of material. The benefits of separating the directions of the electrical and thermal currents have been demonstrated convincingly at low temperatures using the transverse thermomagnetic effects, but at ordinary temperatures the transverse thermoelectric effects are of more interest. These effects are to be found in any material in which the Seebeck coefficient is anisotropic. However, for them to be of practical value, a large and strongly anisotropic Seebeck coefficient must be combined with a high ratio of electrical to thermal conductivity. There is no known homogeneous substance in which this combination of properties is to be found. On the other hand, it is possible to obtain the required parameters in a synthetic material consisting of two phases. The two components A and B should form a couple with a large conventional figure of merit Z AB. The optimum value for the transverse figure of merit Z ? can approach Z AB only when the two components have very different electrical and thermal conductivities. Various workers have used semiconductor-metal or semiconductor-semimetal combinations in attempts to satisfy these requirements. It has also been proposed that the necessary combination of properties might be met by making one of the components porous. The work that has been done on synthetic transverse thermoelements will be reviewed, and the prospects for practical devices will be discussed.

Goldsmid, H. J.

2011-05-01

101

Anomalous and planar Nernst effects in thin films of the half-metallic ferromagnet La2/3Sr1/3MnO3  

NASA Astrophysics Data System (ADS)

We report the planar and anomalous Nernst effects in epitaxial thin films of spin polarized La2/3Sr1/3MnO3. The thermal counterpart of the anomalous Hall effect in this material (i.e., the anomalous Nernst effect) shows an extreme sensitivity to any parasitic thermal gradient, resulting in large asymmetric voltages under small temperature differences. This should be considered when interpreting the magnitude of the electrical response in nanostructures and devices that operate under high current densities. Finally, none of the observed magnetothermoelectric signals is related to the spin Seebeck effect in this material.

Bui, Cong Tinh; Rivadulla, F.

2014-09-01

102

Spin-dependent thermoelectric effects in graphene-based spin valves.  

PubMed

Using first-principles calculations combined with non-equilibrium Green's function (NEGF), we investigate spin-dependent thermoelectric effects in a spin valve which consists of zigzag graphene nanoribbon (ZGNR) electrodes with different magnetic configurations. We find that electron transport properties in the ZGNR-based spin valve are strongly dependent on the magnetic configurations. As a result, with a temperature bias, thermally-induced currents can be controlled by switching the magnetic configurations, indicating a thermal magnetoresistance (MR) effect. Moreover, based on the linear response assumption, our study shows that the remarkably different Seebeck coefficients in the various magnetic configurations lead to a very large and controllable magneto Seebeck ratio. In addition, we evaluate thermoelectric properties, such as the power factor, electron thermal conductance and figure of merit (ZT), of the ZGNR-based spin valve. Our results indicate that the power factor and the electron thermal conductance are strongly related to the transmission gap and electron-hole symmetry of the transmission spectrum. Moreover, the value of ZT can reach 0.15 at room temperature without considering phonon scattering. In addition, we investigate the thermally-controlled magnetic distributions in the ZGNR-based spin valve and find that the magnetic distribution, especially the local magnetic moment around the Ni atom, is strongly related to the thermal bias. The very large, multi-valued and controllable thermal magnetoresistance and Seebeck effects indicate the strong potential of ZGNR-based spin valves for extremely low-power consuming spin caloritronics applications. The thermally-controlled magnetic moment in the ZGNR-based spin valve indicates its possible applications for information storage. PMID:23151965

Zeng, Minggang; Huang, Wen; Liang, Gengchiau

2013-01-01

103

Spin-dependent thermoelectric effects in graphene-based spin valves  

NASA Astrophysics Data System (ADS)

Using first-principles calculations combined with non-equilibrium Green's function (NEGF), we investigate spin-dependent thermoelectric effects in a spin valve which consists of zigzag graphene nanoribbon (ZGNR) electrodes with different magnetic configurations. We find that electron transport properties in the ZGNR-based spin valve are strongly dependent on the magnetic configurations. As a result, with a temperature bias, thermally-induced currents can be controlled by switching the magnetic configurations, indicating a thermal magnetoresistance (MR) effect. Moreover, based on the linear response assumption, our study shows that the remarkably different Seebeck coefficients in the various magnetic configurations lead to a very large and controllable magneto Seebeck ratio. In addition, we evaluate thermoelectric properties, such as the power factor, electron thermal conductance and figure of merit (ZT), of the ZGNR-based spin valve. Our results indicate that the power factor and the electron thermal conductance are strongly related to the transmission gap and electron-hole symmetry of the transmission spectrum. Moreover, the value of ZT can reach 0.15 at room temperature without considering phonon scattering. In addition, we investigate the thermally-controlled magnetic distributions in the ZGNR-based spin valve and find that the magnetic distribution, especially the local magnetic moment around the Ni atom, is strongly related to the thermal bias. The very large, multi-valued and controllable thermal magnetoresistance and Seebeck effects indicate the strong potential of ZGNR-based spin valves for extremely low-power consuming spin caloritronics applications. The thermally-controlled magnetic moment in the ZGNR-based spin valve indicates its possible applications for information storage.

Zeng, Minggang; Huang, Wen; Liang, Gengchiau

2012-12-01

104

Photo-controllable thermoelectric properties with reversibility and photo-thermoelectric effects of tungsten trioxide accompanied by its photochromic phenomenon  

NASA Astrophysics Data System (ADS)

The addition of photo-controllable properties to tungsten trioxide (WO3) is of interest for developing practical applications of WO3 as well as for interpreting such phenomena from scientific viewpoints. Here, a sputtered crystalline WO3 thin film generated thermoelectric power due to ultraviolet (UV) light-induced band-gap excitation and was accompanied by a photochromic reaction resulting from generating W5+ ions. The thermoelectric properties (electrical conductivity (?) and Seebeck coefficient (S)) and coloration of WO3 could be reversibly switched by alternating the external stimulus between UV light irradiation and dark storage. After irradiating the film with UV light, ? increased, whereas the absolute value of S decreased, and the photochromic (coloration) reaction was detected. Notably, the opposite behavior was exhibited by WO3 after dark storage, and this reversible cycle could be repeated at least three times. Moreover, photo-thermoelectric effects (photo-conductive effect (photo-conductivity, ?photo) and photo-Seebeck effect (photo-Seebeck coefficient, Sphoto)) were also detected in response to visible-light irradiation of the colored WO3 thin films. Under visible-light irradiation, ?photo and the absolute value of Sphoto increased and decreased, respectively. These effects are likely attributable to the excitation of electrons from the mid-gap visible light absorption band (W5+ state) to the conduction band of WO3. Our findings demonstrate that the simultaneous, reversible switching of multiple properties of WO3 thin film is achieved by the application of an external stimulus and that this material exhibits photo-thermoelectric effects when irradiated with visible-light.

Azuma, Chiori; Kawano, Takuto; Kakemoto, Hirofumi; Irie, Hiroshi

2014-11-01

105

Effect of hot-press sintering temperature on thermal transport properties of TiSe2  

NASA Astrophysics Data System (ADS)

Titanium diselenide (TiSe2) alloy was prepared using solid state reaction method and hot press sintering. The effects of hot press sintering temperatures on TiSe2 were studied on the thermal transport properties of the material. As grown material shows pure TiSe2 phase and layer structure. Increasing sintering temperature results in reduced electrical resistivity ? whereas the Seebeck coefficient, ? show no significant relative change. Reduced electrical resistivity may be attributed to the increased crystalline nature. This results in improved power factor showing the optimum condition for producing better TiSe2 thermoelectric material.

Bhatt, R.; Bhattacharya, S.; Basu, R.; Patel, M.; Singh, A.; Bhatt, P.; Aswal, D. K.; Gupta, S. K.

2013-06-01

106

Specific salt effects on thermophoresis of charged colloids.  

PubMed

We study the Soret effect of charged polystyrene particles as a function of temperature and electrolyte composition. As a main result we find that the Soret coefficient is determined by charge effects, and that non-ionic contributions are small. In view of the well-known electric-double layer interactions, our thermal field-flow fractionation data lead us to the conclusion that the Soret effect originates to a large extent from diffusiophoresis in the salt gradient and from the electrolyte Seebeck effect, both of which show strong specific-ion effects. Moreover, we find that thermophoresis of polystyrene beads is fundamentally different from proteins and aqueous polymer solutions, which show a strong non-ionic contribution. PMID:24652409

Eslahian, Kyriakos A; Majee, Arghya; Maskos, Michael; Würger, Alois

2014-03-28

107

Specific Salt Effects on Thermophoresis of Charged Colloids  

E-print Network

We study the Soret effect of charged polystyrene particles as a function of temperature and electrolyte composition. As a main result we find that the Soret coefficient is determined by charge effects, and that non-ionic contributions are small. In view of the well-kown electric-double layer interactions, our thermal field-flow fractionation data lead us to the conclusion that the Soret effect originates to a large extent from diffusiophoresis in the salt gradient and from the electrolyte Seebeck effect, both of which show strong specific-ion effects. Moreover, we find that thermophoresis of polystyrene beads is fundamentally different from proteins and aqueous polymer solutions, which show a strong non-ionic contribution.

Kyriakos A. Eslahian; Arghya Majee; Michael Maskos; Alois Würger

2014-01-28

108

Thermal Cycling Effects on the Thermoelectric Properties of n-Type In, Ce based Skutterudite Compounds  

SciTech Connect

N-type In-filled CoSb3 are known skutterudite compounds that have shown promising thermoelectric (TE) properties resulting in high dimensionless figure of merit values at elevated temperatures. Their use in various waste heat recovery applications will require that they survive and operate after exposure to harsh thermal cycling environments. This research focused on uncovering the thermal cycling effects on thermoelectric properties of n-type In0.2Co4Sb12 and In0.2Ce0.15Co4Sb12 skutterudite compositions as well as quantifying their temperature-dependent structural properties (elastic modulus, shear modulus, and Poisson's ratio). It was observed that the Seebeck coefficient and resistivity increased only slightly in the double-filled In,Ce skutterudite materials upon thermal cycling. In the In-filled skutterudites the Seebeck coefficient remained approximately the same on thermal cycling, while electrical resistivity increased significantly after thermal cycling. Results also show that thermal conductivity marginally decreases in the case of In-filled skutterudites, whereas the reduction is more pronounced in In, Ce-based skutterudite compounds. The possible reason for this kind of reduction can be attributed to grain pinning effects due to formation of nano inclusions. High temperature structural property measurements (i.e., Young's modulus and shear modulus) are also reported and the results show that these structural properties decrease slowly as temperature increases and the compounds are structurally stable after numerous thermal cycles.

Biswas, Krishnendu; Subramanian, Mas A.; Good, Morris S.; Roberts, Kamandi C.; Hendricks, Terry J.

2012-06-14

109

Observation of the Spin Peltier Effect for Magnetic Insulators  

NASA Astrophysics Data System (ADS)

We report the observation of the spin Peltier effect (SPE) in the ferrimagnetic insulator yttrium iron garnet (YIG), i.e., a heat current generated by a spin current flowing through a platinum (Pt)|YIG interface. The effect can be explained by the spin transfer torque that transforms the spin current in the Pt into a magnon current in the YIG. Via magnon-phonon interactions the magnetic fluctuations modulate the phonon temperature that is detected by a thermopile close to the interface. By finite-element modeling we verify the reciprocity between the spin Peltier and spin Seebeck effect. The observed strong coupling between thermal magnons and phonons in YIG is attractive for nanoscale cooling techniques.

Flipse, J.; Dejene, F. K.; Wagenaar, D.; Bauer, G. E. W.; Youssef, J. Ben; van Wees, B. J.

2014-07-01

110

Seebeck and Peltier coefficients of hydrogen electrodes related to the  

E-print Network

in different chemical and electrochemical systems. She further went on showing how they can be mini- mized through the right knowledge of entropy of the system in question, and how the lost work in heat for how to continue Masters' degree in Chemistry was motivated by the description of the specialization course. I

Kjelstrup, Signe

111

Spin-dependent thermoelectric effects in transport through a nanoscopic junction involving a spin impurity  

NASA Astrophysics Data System (ADS)

Conventional and spin-related thermoelectric effects in transport through a magnetic tunnel junction with a large-spin impurity, such as a magnetic molecule or atom, embedded into the corresponding barrier are studied theoretically in the linear-response regime. The impurity is described by the giant spin Hamiltonian, with both uniaxial and transverse magnetic anisotropy taken into account. Owing to the presence of the transverse component of magnetic anisotropy, the spin of a tunneling electron can be reversed during scattering on the impurity, even in the low-temperature regime. This reversal appears due to the exchange interaction of tunneling electrons with the magnetic impurity. We calculate Seebeck and spin Seebeck coefficients, and analyze their dependence on various parameters of the spin impurity and tunnel junction. In addition, conventional and spin figures of merit as well as the electronic contribution to heat conductance are considered. We also show that pure spin current can be driven by a spin bias applied to the junction with spin impurity, even if no electron transfer between the electrodes can take place. The underlying mechanism employs single-electrode tunneling processes (electrode-spin exchange interaction) and the impurity as an intermediate reservoir of angular momentum.

Misiorny, Maciej; Barna?, Józef

2014-06-01

112

Effect of a transverse magnetic field on solidification structure in directionally solidified Sn-Pb hypoeutectic alloys  

NASA Astrophysics Data System (ADS)

Effect of a transverse magnetic field on the macrosegregation and the growth of the Sn dendrite in the directionally solidified Sn-Pb alloys was investigated experimentally. The results indicated that the magnetic field modified the shape of the liquid/solid interface and the dendrite morphology significantly. Indeed, the application of the magnetic field caused the formation of the sloping interface and the refinement of the dendrite. It is also found that the magnetic field decreased the mushy zone length. These effects were enhanced with the increase of the magnetic field intensity and the decrease of the growth speed. Further, the Seebeck thermoelectric force (ES) at the liquid/solid interface in the Sn-20 wt%Pb alloy was measured in-situ and the results indicated that the value of the Seebeck thermoelectric force was about 1 ?V. The modification of the solidification structure during directional solidification under the magnetic field may be attributed to the interdendritic thermoelectric magnetic convection (TEMC).

Du, Dafan; Lu, Zhenyuan; Gagnoud, Annie; Fautrelle, Yves; Ren, Zhongming; Lu, Xionggang; Moreau, Rene; Li, Xi

2014-09-01

113

Thermal Cycling Effects on the Thermoelectric Properties of n-Type In,Ce-Based Skutterudite Compounds  

NASA Astrophysics Data System (ADS)

n-Type In-filled CoSb3 is a known skutterudite compound that has shown promising thermoelectric (TE) properties resulting in high dimensionless figure of merit values at elevated temperatures. Use in various waste heat recovery applications will require survival and operation after exposure to harsh thermal cycling environments. This research focused on uncovering the thermal cycling effects on TE properties of n-type In0.2Co4Sb12 and In0.2Ce0.15Co4Sb12 skutterudite compositions as well as quantifying their temperature-dependent structural properties (elastic modulus, shear modulus, and Poisson's ratio). It was observed that the Seebeck coefficient and resistivity increased only slightly in the double-filled In,Ce skutterudite materials upon thermal cycling. In the In-filled skutterudites the Seebeck coefficient remained approximately the same on thermal cycling, while the electrical resistivity increased significantly after thermal cycling. Results also show that the thermal conductivity marginally decreases in the case of In-filled skutterudites, whereas the reduction is more pronounced in In,Ce-based skutterudite compounds. The possible reason for this kind of reduction can be attributed to grain pinning effects due to formation of nanoinclusions. High-temperature structural property measurements (i.e., Young's modulus and shear modulus) are also reported. The results show that these structural properties decrease slowly as temperature increases and that the compounds are structurally stable after numerous (up to 200) thermal cycles.

Biswas, Krishnendu; Subramanian, M. A.; Good, Morris S.; Roberts, Kamandi C.; Hendricks, Terry J.

2012-06-01

114

Competing spin pumping effects in magnetic hybrid structures  

NASA Astrophysics Data System (ADS)

Pure spin current can be detected by its conversion into charge current in nanometer thick nonmagnetic metal layer with large spin-orbit coupling by means of the inverse spin Hall effect (ISHE). Recently, it has been shown that the metallic ferromagnet Permalloy (Py) can also be used as spin current detector in experiments in which an ISHE voltage is created in a Py layer in contact with the insulating ferromagnet yttrium iron garnet (YIG) under a thermal gradient in the longitudinal spin Seebeck configuration. Here, we report experiments with microwave driven spin pumping in heterostructures made with single crystal YIG film and a nanometer thick Py or Pt layer that show that Py behaves differently than nonmagnetic metals as a spin current detector. The results are attributed to the competition between the spin currents generated by the dynamics of the magnetizations in YIG and in Py, which are exchange coupled at the interface.

Azevedo, A.; Alves Santos, O.; Fonseca Guerra, G. A.; Cunha, R. O.; Rodríguez-Suárez, R.; Rezende, S. M.

2014-02-01

115

Large inverse spin Hall effect in the antiferromagnetic metal Ir20Mn80  

NASA Astrophysics Data System (ADS)

A spin current is usually detected by converting it into a charge current through the inverse spin Hall effect (ISHE) in thin layers of a nonmagnetic metal with large spin-orbit coupling, such as Pt, Pd, and Ta. Here we demonstrate that Ir20Mn80, a high-temperature antiferromagnetic metal that is commonly employed in spin-valve devices, exhibits a large inverse spin Hall effect, as recently predicted theoretically. We present results of experiments in which the spin currents are generated either by microwave spin pumping or by the spin Seebeck effect in bilayers of singe-crystal yttrium iron garnet (YIG)/Ir20Mn80 and compare them with measurements in YIG/Pt bilayers. The results of both measurements are consistent, showing that Ir20Mn80 has a spin Hall angle similar to Pt, and that it is an efficient spin-current detector.

Mendes, J. B. S.; Cunha, R. O.; Alves Santos, O.; Ribeiro, P. R. T.; Machado, F. L. A.; Rodríguez-Suárez, R. L.; Azevedo, A.; Rezende, S. M.

2014-04-01

116

Effect of Heat Treatment in Air on Thermoelectric Properties of Polycrystalline Type-I Silicon-Based Clathrate: Ba8Al15Si31  

NASA Astrophysics Data System (ADS)

The effect of heat treatment in air on the thermoelectric properties was investigated for polycrystalline Ba8Al15Si31, where the Al content is almost at the maximum in the Ba8Al x Si46-x system, to evaluate the thermal stability in air at high temperatures, which is indispensable for practical use in thermoelectric applications. Samples were prepared by combining arc melting and spark plasma sintering techniques. Heat treatments were performed in air at 873 K for 10 days and 20 days. The Seebeck coefficient, electrical conductivity, and thermal conductivity were measured before and after the heat treatments. The microstructure and chemical composition were also analyzed before and after the heat treatments, using scanning electron microscopy with energy-dispersive x-ray spectroscopy. Although an oxidation layer was formed on the surface by the heat treatment in air, the chemical composition of the interior of Ba8Al15Si31 was found to be stable in air at 873 K for 10 days and 20 days. The Seebeck coefficient, the electrical conductivity, and the thermal conductivity were found to be almost unchanged after the heat treatment, indicating that Ba8Al15Si31 clathrate is promising as a thermoelectric material with high thermal stability for use in air at 873 K.

Anno, Hiroaki; Shirataki, Ritsuko

2014-09-01

117

Effect of Ca doping level on the laser-induced voltages in tilted La1- x Ca x MnO3 (0.1 ? x ? 0.7) thin films  

NASA Astrophysics Data System (ADS)

Tilted La1- x Ca x MnO3 (0.1 ? x ? 0.7) thin films have been grown on vicinal cut LaAlO3 (100) substrate by pulsed laser deposition. The laser-induced voltage effect was studied at room temperature with the KrF excimer laser using as the thermal source. The relationships between Ca doping level and voltage signal, response time and anisotropy Seebeck coefficient were established. The voltage signal and anisotropy Seebeck coefficient increase at first with increasing Ca doping level, reach a maximum at the same Ca content around x = 0.5, and then decrease. The respond time decreases with the Ca concentration increasing, and changes very little after x = 0.5. The figure of merit F m was also the largest at this doping level, indicating a potential good performance of the photodetector devices. The variation of intrinsic structural and transport anisotropy induced by the change of Ca concentration has been proposed to account for the different LIV effects observed in LCMO thin films.

Ma, Ji; Theingi, Mya; Zhang, Hui; Chen, Qingming; Liu, Xiang

2014-03-01

118

Comment on "Unexpected size effect in the thermopower of thin-film stripes" [J. Appl. Phys. 110, 083709 (2011)  

NASA Astrophysics Data System (ADS)

In a recent article, Sun et al. [J. Appl. Phys. 110, 083709 (2011)] claim to measure a size-dependent thermoelectric effect in a micron-scale single-metal thermocouple. In this Comment, we demonstrate that the observed phenomenon is not due to a size-dependent Seebeck effect as claimed, but is rather wire-size-dependent heat transport that causes unequal heating at the bonding pads. As a result, the bonding pads are at two different temperatures, and the observed voltage corresponds to a thermoelectric effect of a parasitic thermocouple formed between their metal structure and the bonding-pad wires. We provide simulations and suggest a control experiment based on their structure that supports our contention that the observation depends on width-dependent heat transport in the wires.

Szakmany, Gergo P.; Orlov, Alexei O.; Bernstein, Gary H.; Porod, Wolfgang

2014-06-01

119

Effects of Nano-?-Al2O3 Dispersion on the Thermoelectric and Mechanical Properties of CoSb3 Composites  

NASA Astrophysics Data System (ADS)

Nano-?-Al2O3/CoSb3 composites with different ?-Al2O3 contents were prepared by spark plasma sintering. The effects of ?-Al2O3 addition on the microstructure, the thermoelectric properties, and the mechanical properties were studied in this article. It is found that ?-Al2O3 nanoparticles locate mainly at grain boundaries of the matrix. The dispersed particles decrease both the electrical conductivity and the thermal conductivity, but make the Seebeck coefficient increase. The dimensionless figure of merit is nearly unchanged by the dispersion. However, the introduction of nano-?-Al2O3 is very effective in improving the mechanical performance of the composites. The compressive strength and flexural strength of the 1.0 wt.% nano-?-Al2O3 dispersed samples are improved by 42.7 and 52.0%, respectively, compared with the nondispersed samples.

Wen, Pengfei; Mei, Hong; Zhai, Pengcheng; Duan, Bo

2013-11-01

120

Transport Magnetic Proximity Effects in Platinum  

NASA Astrophysics Data System (ADS)

Platinum (Pt) metal, being non-magnetic and having a strong spin-orbit coupling interaction, has been central in detecting pure spin current and establishing most of the recent spin-based phenomena. Thus, it is important to ascertain the transport and magnetic characteristics of thin Pt films in contact with a ferromagnet. In this work, we use both electric and thermal means to conclusively show the transport magnetic proximity effects (MPE) of thin Pt film in contact with ferromagnetic insulator YIG. At thicknesses comparable to, and less than, the spin diffusion length, the strong ferromagnetic characteristics in Pt films on YIG are indistinguishable from those of ferromagnetic permalloy on YIG. [1] The MPE occurs at the interface and decreases exponentially away from the interface, concentrating in only a few monolayers. As a result, the pure spin current detected by a thin Pt is tainted with a spin polarized current. The pure spin current phenomena, such as the inverse spin Hall effect and the spin Seebeck effect, have been contaminated with the anomalous Hall effect and the anomalous Nernst effect respectively. These results raise serious questions about the suitability, and the validity, of using Pt in establishing pure spin current phenomena; on the other hand, a much stronger spin-based effect can be induced by the MPE at the interface. This research is in collaboration with X. Fin, Y. P. Chen, J. Wu, and J. Q. Xiao (University of Delaware), T. Y. Chen (Arizona State University) and D. Qu, W. G. Wang, and C. L. Chien (The Johns Hopkins University).[4pt] [1] S. Y. Huang et al., Phys. Rev. Letts. 109, 107204 (2012).

Huang, Ssu-Yen

2013-03-01

121

Induced Magneto-transport Effects in Non-magnetic Metals on Yttrium Iron Garnet  

NASA Astrophysics Data System (ADS)

Yttrium iron garnet (YIG) was called ``spin Seebeck insulator,'' for it supports heat-generated pure spin currents. Pt thin film, with strong spin-orbit interaction, is used as a spin current generator or detector based on the spin Hall effect or the inverse spin Hall effect. The combination of these two materials plays a very important role in spintronics. A recent magnetotransport study shows strong evidence of a magnetic proximity effect in thin Pt films deposited on YIG. Here, we present a magneto-transport study of several non-magnetic (NM) metal films (e.g. Pt, Pd) on YIG films grown on gadolinium gallium garnet substrates with laser molecular beam epitaxy. The anisotropic magnetoresistance (AMR) and anomalous Hall effect (AHE) reveal clear ferromagnetic characteristics in NM films. The magnitude of the AHE angle ? in Pd/YIG structure increases with decreasing temperature, while ? in Pt/YIG structure has a sign reversal at an intermediate temperature. Both AMR and AHE have been investigated as the NM film thickness is varied and an optimal effective thickness is identified. The effect of annealing has also been studied and the results are consistent with the observed thickness dependence. In thin NM films, a ln(T) temperature dependence with a resistivity minimum is observed at low temperatures, suggesting that the Kondo effect may be relevant. Detailed discussions about the origin of these effects will be presented.

Lin, Tao; Tang, Chi; Shi, Jing

2013-03-01

122

Thermomagnonic spin transfer and Peltier effects in insulating magnets  

NASA Astrophysics Data System (ADS)

The recent discovery of the spin Seebeck effect [1] in metals, insulators and semiconductors stimulated development of spincaloritronics [2]. The possibility of measuring the Onsager reciprocal spin Peltier effect has been investigated recently as well. In our theoretical work [3], we study the fictitious electromagnetic fields induced by magnetic textures which may offer an alternative route for observing the spin Peltier effect. Particularly, in an insulating ferromagnet a moving magnetic texture should effectively drive the spin (wave) current which in turn should lead to the heat current by the spin Peltier effect. We further study the coupled magnon energy transport and collective magnetization dynamics in ferromagnets with magnetic textures. We conclude that the analogy between the fictitious electromagnetic fields and real fields should lead to magnonic counterparts of such effects as the Hall effect, the Ettingshausen effect, the Nernst effect, and the Righi-Leduc effect. By constructing a phenomenological theory based on irreversible thermodynamics, we describe motion of domain walls by thermal gradients and generation of heat flows by magnetization dynamics. From microscopic description based on magnon kinetics, we estimate the transport coefficients and analyze the feasibility of energy-related applications (e.g. nanoscale heat pumps [4]) in insulating ferromagnets, such as yttrium iron garnet and europium oxide. Our estimates show that the viscous coupling effects between magnetization dynamics and magnon flows can be strong in materials with low spin densities (e.g. dilute magnetic systems) and narrow domain walls, which can allow the magnonic manipulation of magnetization dynamics and heat pumping.[4pt] [1] K. Uchida et al. Nature 455, 778 (2008).[0pt] [2] G. E. W. Bauer, A. H. MacDonald, S. Maekawa, Solid State Commun. 150, 459 (2010).[0pt] [3] A. A. Kovalev and Y. Tserkovnayk, arXiv:1106.3135.[0pt] [4] A. A. Kovalev and Y. Tserkovnyak, Solid State Commun. 150, 500 (2010).

Kovalev, Alexey A.

2012-02-01

123

Thermoelectric effects and magnetic anisotropy of Ga1-xMnxAs thin films  

NASA Astrophysics Data System (ADS)

The transverse voltages generated in a Ga1-xMnxAs ferromagnetic semiconductor in planar Hall effect and transverse spin Seebeck effect configurations are systematically analyzed. The observed field dependences consist of symmetric and asymmetric contributions. The former is attributed to the planar Nernst effect in the magnetic film in the presence of an in-plane temperature gradient, while the latter is caused by the anomalous Nernst effect due to spurious out-of-plane temperature gradients with a coefficient as high as 500 ?V/K. We also report on the experimental observation of the planar Hall effect measured at different temperatures. Using a Stoner-Wohlfarth model for data analysis, the anisotropy constants Ku and Kc of superimposed uniaxial and cubic anisotropies in the magnetic film are determined. The temperature dependence of the Ku/Kc ratio reveals a gradual substitution of the cubic anisotropy dominating at low temperatures with the uniaxial anisotropy as the temperature rises. This behavior is confirmed by the simultaneous domain observation using Kerr microscopy, demonstrating different field evolutions of the domain structure at different temperatures.

Soldatov, I. V.; Panarina, N.; Hess, C.; Schultz, L.; Schäfer, R.

2014-09-01

124

Cement and Concrete Research 29 (1999) 19891993 0008-8846/99/$ see front matter 2000 Elsevier Science Ltd. All rights reserved.  

E-print Network

the linearity and reversibility of the Seebeck effect. Silica fume and latex as admixtures had minor influence paste; Electrical properties; Silica fume; Thermoelectric 1. Introduction The Seebeck effect depends not only on the fiber content, but also on the admixtures present [3,4]. The use of silica fume

Chung, Deborah D.L.

125

Effect of Doping on Thermoelectric Properties of Delafossite-Type Oxide CuCrO2  

NASA Astrophysics Data System (ADS)

We have studied the effects of doping on the high-temperature thermoelectric properties of the delafossite-type oxide CuCrO2. The single or double doping of divalent cations for Cr3+ ions was carried out to introduce hole carriers. For the first step, we measured the electrical conductivity ? and Seebeck coefficient S of single-doped samples, and calculated the power factor P=?S2. Mg-, Zn-, Ca-, Ni-, and Co-doped samples showed a higher power factor than CuCrO2, while the Fe-, V-, and Mn-doped samples exhibited a lower power factor. The maximum power factor P=2.36×10-4 W/mK2 at 1100 K was obtained with the Mg-doped sample. The above tendencies of the power factor are well explained by the valence states and ionic radii of the dopants. For the next step, Mg and M (M = Zn, Ca, Ni, or Co) double-doped samples were prepared. Since there was no impurity phase in the Mg+Ni cases, we have elucidated the structure and high-temperature thermoelectric properties of CuCr0.97-xMg0.03NixO2 (0Seebeck coefficient of the double-doped samples was higher than that of the Mg-doped sample, in which the total number of hole carriers (i.e., the sum of the hole carriers in the Cu and Cr sites) is decreasing. The Seebeck coefficient of the double-doped samples was higher than 225 µV/K from 300 to 1100 K. The thermal conductivity of the double-doped samples (?>6 W/mK) was higher than that of the Mg-doped sample. As a result, the maximum dimensionless figure of merit ZT=?S2T/?=0.10 was realized with the sample of x=0.04 at 1100 K, which was twice as high as that of the Mg-doped sample.

Hayashi, Kei; Sato, Ken-ichi; Nozaki, Tomohiro; Kajitani, Tsuyoshi

2008-01-01

126

Using first principles Destiny Functional Theory methods to model the Seebeck coefficient of bulk silicon  

E-print Network

Thermoelectrics are gaining significant amounts of attention considering their relevance today in the areas of sustainable energy generation and energy efficiency. In this thesis, the thermoelectric properties of bulk ...

Mehra, Saahil

2008-01-01

127

Importance of relativistic effects in electronic structure and thermopower calculations for Mg2Si, Mg2Ge, and Mg2Sn  

NASA Astrophysics Data System (ADS)

We present a theoretical study of the influence of relativistic effects on the electronic band structure and thermopower of Mg2X (X = Si, Ge, Sn) semiconductors. The full potential Korringa-Kohn-Rostoker (KKR) method is used, and a detailed comparison between the fully relativistic and semirelativistic electronic structure features is done. We show that the spin-orbit (S-O) interaction splits the valence band at ? point in good agreement with the experimental data, and this effect strongly depends on X atom. The S-O modifications of the topology of the ?-centered holelike Fermi surface pockets lead to a change in electron transport properties, which are investigated using the Boltzmann approach. In addition, a simple and efficient method is presented for the calculation of density of states effective mass m*, and then used to examine the impact of relativistic effects on m*. It is found that the S-O coupling of the valence bands reduces the effective mass and therefore significantly lowers the thermopower, primarily in Mg2Sn, but also in Mg2Ge. A detrimental influence of the S-O interaction on the thermoelectric performance of p-type Mg2X is analyzed as a function of temperature (10-900 K) and carrier concentration (1018-1022 cm-3). Interestingly, similar calculations in n-type Mg2X, show a negligible effect of the S-O interaction on the lowest conduction bands and, consequently, also on the Seebeck coefficient.

Kutorasinski, K.; Wiendlocha, B.; Tobola, J.; Kaprzyk, S.

2014-03-01

128

Poole-Frenkel effect in sputter-deposited CuAlO(2+x) nanocrystals.  

PubMed

Field-assisted thermionic emission within a sputter-deposited, nanocrystalline thin film of CuAlO2.06 is observed for the first time, and explained in terms of the Poole-Frenkel model. The presence of adsorbed oxygen ions as trap-states at the grain boundary regions of the nanostructured thin film is considered to manifest this phenomenon. Under an applied field, the barrier of the trap potential is lowered and thermal emission of charge carriers takes place at different sample temperatures to induce nonlinearity in the current (I)-voltage (V) characteristics of the nanomaterial. Fitting of the Poole-Frenkel model with the I-V data shows that the nonlinearity is effective above 50 V under the operating conditions. Calculations of the energy of the trap level, acceptor level and Fermi level reveal the existence of deep level trap-states and a shallow acceptor level with acceptor concentration considerably higher than the trap-states. Hall measurements confirm the p-type semiconductivity of the film, with a hole concentration around 10(18) cm(-3). Thermopower measurements give a room-temperature Seebeck coefficient around 130 ?V K(-1). This temperature-dependent conductivity enhancement within CuAlO2 nanomaterial may find interesting applications in transparent electronics and high-voltage applications for power supply networks. PMID:23535666

Banerjee, Arghya Narayan; Joo, Sang Woo

2013-04-26

129

Compositional disorder and its effect on the thermoelectric performance of Zn3P2 nanowire-copper nanoparticle composites  

NASA Astrophysics Data System (ADS)

Recent studies indicated that nanowire format of materials is ideal for enhancing the thermoelectric performance of materials. Most of these studies were performed using individual nanowires as the test elements. It is not currently clear whether bulk assemblies of nanowires replicate this enhanced thermoelectric performance of individual nanowires. Therefore, it is imperative to understand whether enhanced thermoelectric performance exhibited by individual nanowires can be extended to bulk assemblies of nanowires. It is also imperative to know whether the addition of metal nanoparticle to semiconductor nanowires can be employed for enhancing their thermoelectric performance further. Specifically, it is important to understand the effect of microstructure and composition on the thermoelectric performance on bulk compound semiconductor nanowire-metal nanoparticle composites. In this study, bulk composites composed of mixtures of copper nanoparticles with either unfunctionalized or 1,4-benzenedithiol (BDT) functionalized Zn3P2 nanowires were fabricated and analyzed for their thermoelectric performance. The results indicated that use of BDT functionalized nanowires for the fabrication of composites leads to interface-engineered composites that have uniform composition all across their cross-section. The interface engineering allows for increasing their Seebeck coefficients and electrical conductivities, relative to the Zn3P2 nanowire pellets. In contrast, the use of unfunctionalized Zn3P2 nanowires for the fabrication of composite leads to the formation of composites that are non-uniform in composition across their cross-section. Ultimately, the composites were found to have Zn3P2 nanowires interspersed with metal alloy nanoparticles. Such non-uniform composites exhibited very high electrical conductivities, but slightly lower Seebeck coefficients, relative to Zn3P2 nanowire pellets. These composites were found to show a very high zT of 0.23 at 770 K, orders of magnitude higher than either interface-engineered composites or Zn3P2 nanowire pellets. The results indicate that microstructural composition of semiconductor nanowire-metal nanoparticle composites plays a major role in determining their thermoelectric performance, and such composites exhibit enhanced thermoelectric performance.

Brockway, Lance; Vasiraju, Venkata; Vaddiraju, Sreeram

2014-03-01

130

?he Effect of Ge on Mg2Si0.6-x Sn0.4Ge x Materials  

NASA Astrophysics Data System (ADS)

In this work, we investigate the influence of the introduction of Ge on the thermoelectric properties of Bi-doped quaternary Mg2Si0.6- x Sn0.4Ge x alloys. Mg2Si0.58- x Sn0.4Bi0.02Ge x materials were fabricated by a low temperature reaction method, followed by hot pressing. Structure and phase composition of the obtained hot-pressed pellets were observed by x-ray diffraction. Morphology and chemical composition were monitored by scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy. The results indicate a natural tendency of the material to phase separate into Si-rich, Sn-rich, and Ge-rich regions, which seem to become finer in size with Ge concentration. The compounds have been characterized by electrical conductivity, Seebeck coefficient, and thermal conductivity measurements in the temperature range of 300-823 K. The effect of Ge in the lattice thermal conductivity is discussed in terms of solid solution formation as well as effective medium theory.

Vlachos, N.; Hatzikraniotis, E.; Mihailescu, C. N.; Giapintzakis, J.; Kyratsi, Th.

2014-10-01

131

Exploring the doping effects of Ag in p-type PbSe compounds with enhanced thermoelectric performance  

NASA Astrophysics Data System (ADS)

In this study, we prepared a series of Ag-doped PbSe bulk materials by a melting-quenching process combined with a subsequent spark plasma sintering process, and systematically investigated the doping effects of Ag on the thermoelectric properties. Ag substitution in the Pb site does not introduce resonant levels near the valence band edge or detectable change in the density of state in the vicinity of the Fermi level, but moves the Fermi level down and increases the carrier concentration to a maximum value of ~4.7 × 1019 cm-3 which is still insufficient for heavily doped PbSe compounds. Nonetheless, the non-monotonic variation in carrier concentration with increasing Ag content indicates that Ag doping reaches the solution limit at ~1.0% and the excessive Ag presumably acts as donors in the materials. Moreover, the large energy gap of the PbSe-based material wipes off significant 'roll-over' in the Seebeck coefficient at elevated temperatures which gives rise to high power factors, being comparable to p-type Te analogues. Consequently, the maximum ZT reaches ~1.0 for the 1.5% Ag-doped samples with optimized carrier density, which is ~70% improvement in comparison with an undoped sample and also superior to the commercialized p-type PbTe materials.

Wang, Shanyu; Zheng, Gang; Luo, Tingting; She, Xiaoyu; Li, Han; Tang, Xinfeng

2011-11-01

132

Effects of impurity-band conduction on thermoelectric properties of lightly doped p-type CoSb3  

NASA Astrophysics Data System (ADS)

Experimental data on the thermoelectric properties of lightly doped p-type CoSb3 reported by Mandrus et al. [Phys. Rev. B 52, 4926 (1995)], Arushanov et al. [Phys. Rev. B 56, 1911 (1997)], and Dyck et al. [Phys. Rev. B 65, 115204 (2002)] have been analyzed, incorporating both the impurity-band conduction and the nonparabolicity of the valence band. The concentrations of a resonant acceptor, a deep acceptor, and a compensating donor level have been considerably corrected from those obtained in the original studies by Arushanov et al. and Dyck et al. The impurity-band conduction in the deep acceptor level has been proved to be the dominant conduction mechanism at low temperatures in the sample of Dyck et al. while that in the resonant acceptor level has been proved to be the dominant one in the other samples. Especially, the impurity-band conduction has been proved to be predominant up to as high as 400 K in the sample of Mandrus et al. As a result of incorporating the effects of both the impurity-band conduction and the nonparabolicity, the agreement of the simulated Seebeck coefficient with the experimental one has been excellently improved.

Kajikawa, Y.

2014-10-01

133

Effects of indium-filling and synthesis pressure on the thermoelectric properties of CoSb3  

NASA Astrophysics Data System (ADS)

InxCo4Sb12 skutterudite compounds have been prepared successfully at different synthesis pressures by high pressure and high temperature (HPHT) method, the processing time has been reduced from a few days to half an hour. In addition, the effect of synthesis pressure on the thermoelectric properties of In0.4Co4Sb12 compounds has been investigated in this paper. The structure of In0.4Co4Sb12 samples was evaluated by means of X-ray diffraction and scanning electron microscopy (SEM). The Seebeck coefficient, electrical resistivity and thermal conductivity were all measured in the temperature range of room temperature to 673 K. The sample synthesized at 2.0 GPa showed the highest power factor of 29.3 ?Wcm-1K-2 at 373 K. A dimensionless thermoelectric figure of merit (ZT) of 0.51 at 673 K was achieved for n-type In0.4Co4Sb12 prepared at 1.3 GPa, which was significantly enhanced in comparison with pure CoSb3.

Deng, Le; Wang, Li Bin; Qin, Jie Ming; Zheng, Tao; Jia, Xiao Peng; Ma, Hong An

2014-06-01

134

Oxide based thermoelectric materials for large scale power generation  

E-print Network

The thermoelectric (TE) devices are based on the Seebeck and Peltier effects, which describe the conversion between temperature gradient and electricity. The effectiveness of the material performance can be described by ...

Song, Yang, M. Eng. Massachusetts Institute of Technology

2008-01-01

135

The effect of element substitution on high-temperature thermoelectric properties of Ca{sub 3}Co{sub 2}O{sub 6} compounds  

SciTech Connect

Polycrystalline Ca{sub 3}Co{sub 1.8}M{sub 0.2}O{sub 6} (M=Mn, Fe, Co, Ni, Cu) and Ca{sub 2.7}Na{sub 0.3}Co{sub 2}O{sub 6} were synthesized by solid-state reaction to evaluate the effect of substitution on the thermoelectric properties of Ca{sub 3}Co{sub 2}O{sub 6}. Substitution by Mn, Cu and Na appears to increase carrier density, given that electrical resistivity ({rho}) and the Seebeck coefficient (S) were simultaneously reduced. Conversely, Fe substitution seems to reduce carrier density, resulting in a simultaneous increase in S and {rho}. Cu and Na substitution resulted in a significant decrease in {rho} due to enhancement of grain size and grain boundary connectivity, which could have a strong impact on {rho}. Not only the intrinsic substitution effect on the electronic state but also this modification of the microstructure plays an important role in improvement of the thermoelectric power factor, particularly in the case of the Na-substituted sample.

Mikami, Masashi [National Institute of Advanced Industrial Science and Technology, Research Institute of Ubiquitous Energy Devices, 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577 (Japan) and CREST, Japan Science and Technology Agency, 4-1-8, Honcho Kawaguchi, Saitama 332-0012 (Japan)]. E-mail: m-mikami@aist.go.jp; Funahashi, Ryoji [National Institute of Advanced Industrial Science and Technology, Research Institute of Ubiquitous Energy Devices, 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577 (Japan); CREST, Japan Science and Technology Agency, 4-1-8, Honcho Kawaguchi, Saitama 332-0012 (Japan)

2005-05-15

136

Effects of Gd, Co, and Ni doping in La{sub 2/3}Ca{sub 1/3}MnO{sub 3}: Resistivity, thermopower, and paramagnetic resonance  

SciTech Connect

The effect of elemental substitutions on the properties of the ferromagnetic, conducting, highly magnetoresistive compound La{sub 2/3}Ca{sub 1/3}MnO{sub 3} has been studied. The results of Co doping and Ni doping on the Mn site and Gd doping on the La site are reported. These compounds were investigated by x-ray diffraction, magnetization measurements, resistivity measurements, thermopower measurements, and by paramagnetic resonance. The result of replacing La by Gd atoms is to lower the ferromagnetic (or metal-insulator) transition temperature, an effect which is shown to be due to bond bending caused by the lattice adjusting to the size differential between the La and Gd ions. On the other hand, the reduction of the magnetic transition temperature when Mn ions are replaced with Co or Ni ions is {ital not} attributed to changes in the size of the ions. Instead, we ascribe the lowering of the ferromagnetic transition temperature to a weakening of the double-exchange interaction between two unlike ions. The resistivity and Seebeck coefficient in these materials have been investigated as a function of elemental substitution. The magnetic polaron theory of Zhang is used, phenomenologically, to provide a quantitative explanation of these transport properties. In addition, the effect of these elemental substitutions on the linewidths of the paramagnetic resonances is studied and is discussed in terms of exchange narrowing and spin-lattice relaxation.

Rubinstein, M.; Gillespie, D.J.; Snyder, J.E. [U.S. Naval Research Laboratory, Washington, D.C. 20390 (United States)] [U.S. Naval Research Laboratory, Washington, D.C. 20390 (United States); Tritt, T.M. [Clemson University, Clemson, South Carolina 29634 (United States)] [Clemson University, Clemson, South Carolina 29634 (United States)

1997-09-01

137

Effect of Nanoparticles on Electron and Thermoelectric MONA ZEBARJADI,1,5  

E-print Network

is more accurate for particle sizes in the 1 nm to 5 nm range where the point scattering approximation applications such as thermoelectric power generators1 and solar cells.2 The advantage of incorporating the Seebeck coefficient due to electron filtering.4 Adding nano- particles also reduces the electrical

138

Microwave-induced spin currents in ferromagnetic-insulator|normal-metal bilayer system  

NASA Astrophysics Data System (ADS)

A microwave technique is employed to simultaneously examine the spin pumping and the spin Seebeck effect processes in a YIG|Pt bilayer system. The experimental results show that for these two processes, the spin current flows in opposite directions. The temporal dynamics of the longitudinal spin Seebeck effect exhibits that the effect depends on the diffusion of bulk thermal-magnons in the thermal gradient in the ferromagnetic-insulator|normal-metal system.

Agrawal, Milan; Serga, Alexander A.; Lauer, Viktor; Papaioannou, Evangelos Th.; Hillebrands, Burkard; Vasyuchka, Vitaliy I.

2014-09-01

139

Band Structure Engineering in Geometry-Modulated Nanostructures for Thermoelectric Efficiency Enhancement  

NASA Astrophysics Data System (ADS)

The energy subband structure of nanowires with periodically modulated cross-section has been calculated within a continuum model and the effective mass approximation. A characteristic structure of minibands and resonances has been found. This leads to a remarkable enhancement of the Seebeck coefficient compared with that of nonmodulated nanowires of the same dimensions. The Seebeck coefficient enhancement depends on the interplay between the thermal broadening and the quantum confinement. It is pointed out here that the modulation geometry and material parameters can provide design tools for Seebeck coefficient enhancement in nanowires.

Zianni, Xanthippi

2014-10-01

140

The effects of the size and the doping concentration on the power factor of n-type lead telluride nanocrystals for thermoelectric energy conversion.  

PubMed

For the first time, we demonstrate a successful synthesis of colloidal n-type lead telluride nanocrystals doped with iodine. By tuning the reaction time and iodine concentration in the precursor solution, nanocrystals with different sizes and doping concentrations are synthesized. The Seebeck coefficient and electrical conductivity of the nanocrystals are measured on nanocrystal thin films fabricated by dip-coating glass substrates in the nanocrystals solution. Investigations on the influence of size and doping concentration on the electrical properties have been performed. The results show that the size of the nanocrystals significantly influences the electrical conductivity but not the Seebeck coefficient of nanocrystal films, while higher doping concentration leads to lower Seebeck coefficient but higher electrical conductivity in the nanocrystal films. Proof-of-concept thin-film thermoelectric modules are also fabricated using both p-type and n-type PbTe nanocrystals for the conversion of thermal energy into electrical energy. PMID:24527850

Fang, Haiyu; Luo, Zhiqiang; Yang, Haoran; Wu, Yue

2014-03-12

141

The Effects of Substitution of Alkaline Earths or Y for La on Structure and Electrical Properties of LaSrFeO 4  

NASA Astrophysics Data System (ADS)

The effects of the substitution of alkaline earths or Y for La on the structure and electrical properties of LaSrFeO 4 with K 2NiF 4 structure have been investigated. EDTA titration confirmed that Fe 3+ was oxidized to Fe 4+ in an amount corresponding to that of divalent alkaline earth ions substituted for La 3+. The change in the lattice constants was interpreted in terms of the ionic radius of the substituted ions and the Jahn-Teller distortion of the Fe(IV)O 6 octahedra having d4 electronic configuration. All the substituted LaSrFeO 4 samples were semiconducting over the temperature range from 100 to 300 K. The measurement of the Seebeck coefficient revealed that the conduction carriers of LaSrFeO 4 were holes and the carrier concentration increased with increasing amount of Fe 4+. La 1- xAxSrFeO 4 exhibited a monotonic decrease in resistivity and activation energy for conduction with increasing Fe 4+ abundance. The activation energy for conduction did not change by changing the lattice constant where the Fe 4+ abundance did not change with various substituents.

Fujihara, Shinobu; Nakata, Toshiyuki; Kozuka, Hiromitsu; Yoko, Toshinobu

1995-03-01

142

Solar thermoelectrics for small scale power generation  

E-print Network

In the past two decades, there has been a surge in the research of new thermoelectric (TE) materials, driven party by the need for clean and sustainable power generation technology. Utilizing the Seebeck effect, the ...

Amatya, Reja

2012-01-01

143

Modeling of solar thermal selective surfaces and thermoelectric generators  

E-print Network

A thermoelectric generator is a solid-state device that converts a heat flux into electrical power via the Seebeck effect. When a thermoelectric generator is inserted between a solar-absorbing surface and a heat sink, a ...

McEnaney, Kenneth

2010-01-01

144

Effect of Processing Temperature on the Thermoelectric and Optical Properties of Copper Manganite-based Spinels  

NASA Astrophysics Data System (ADS)

This research is focused on investigation of the effect of doping and processing on the microstructure and phase evolution, and the effect of the microstructure and phases on the thermoelectric and optical properties of doped Copper Manganites. Undoped CuMn2O4 and four doped compositions, with nickel and cobalt, were investigated. Detailed processing protocols, including green state processing, were developed to make samples with a range of densities between 65 to 95%. Densification kinetics studies (dilatometry), together with phase and microstructural evolution (XRD, SEM and EDS) were used to demonstrate the role of second phases and especially liquid phase in controlling the densification. It is shown that the Cu content of the oxides plays an important role in controlling the densification and optimum sintering temperature. X-ray diffraction analysis showed that all the majority phase in all materials maintained a cubic spine] structure at all sintering temperatures. The thermoelectric and optical properties were also characterized. Electronic conduction in these oxides is through polaron hopping between Mn3+ and Mn4+. Thus, the thermoelectric properties were controlled largely by the nature of the primary phase, as the secondary phase was too Mn-deficient to support such conduction. Seebeck coefficient ranged from 16 to 185 microV/K, with both composition and the sintering temperature affecting it. The electrical resistivity spanned a wide range of 1.4--2537 O-cm, and was also affected by both the composition, and sintering temperature. Although no general trend was established for the thermal conductivity, it was apparent that the thermal diffusivity was dependent on the density as expected. The FTIR results show that these materials are transparent in the mid-infrared region, showing appreciable transmittance in the range of 12--18 microm. Finally, XPS analysis indicated that the Mn valence states ranged from Mn4+ to Mn2.5+ and generally decreased as sintering temperature increased, in agreement with the results of previous studies on thin films.

Leslie, Clifford J.

145

Temperature gradient measurements by using thermoelectric effect in CNTs-silicone adhesive composite.  

PubMed

This work presents the fabrication and investigation of thermoelectric cells based on composite of carbon nanotubes (CNT) and silicone adhesive. The composite contains CNT and silicon adhesive 1?1 by weight. The current-voltage characteristics and dependences of voltage, current and Seebeck coefficient on the temperature gradient of cell were studied. It was observed that with increase in temperature gradient the open circuit voltage, short circuit current and the Seebeck coefficient of the cells increase. Approximately 7 times increase in temperature gradient increases the open circuit voltage and short circuit current up to 40 and 5 times, respectively. The simulation of experimental results is also carried out; the simulated results are well matched with experimental results. PMID:24748375

Chani, Muhammad Tariq Saeed; Karimov, Kh S; Asiri, Abdullah M; Ahmed, Nisar; Bashir, Muhammad Mehran; Khan, Sher Bahadar; Rub, Malik Abdul; Azum, Naved

2014-01-01

146

Effect of ruthenium substitution in layered sodium cobaltate Na{sub x}CoO{sub 2}: Synthesis, structural and physical properties  

SciTech Connect

Solid-state synthesis of Na{sub 0.71}Co{sub 1-x}Ru{sub x}O{sub 2} compositions shows that ruthenium can be substituted for cobalt in the hexagonal Na{sub 0.71}CoO{sub 2} phase up to x=0.5. The cell expands continuously with increasing ruthenium content. All mixed Co-Ru phases show a Curie-Weiss behaviour with no evidence of magnetic ordering down to 2 K. Unlike the parent phase Na{sub 0.71}CoO{sub 2}, ruthenium-substituted phases are all semiconducting. They exhibit high thermoelectric power, with a maximum of 165 muV/K at 300 K for x=0.3. The Curie constant C and Seebeck coefficient S show a non-monotonic evolution as a function of ruthenium content, demonstrating a remarkable interplay between magnetic properties and thermoelectricity. The presence of ruthenium has a detrimental effect on water intercalation and superconductivity in this system. Applying to Ru-substituted phases the oxidative intercalation of water known to lead to superconductivity in the Na{sub x}CoO{sub 2} system yields a 2-water layer hydrate only for x=0.1, and this phase is not superconducting down to 2 K. - Graphical Abstract: Effect of ruthenium substitution on thermoelectric power in Na{sub 0.71}Co{sub 1-x}Ru{sub x}O{sub 2} (left) and on low-temperature ac susceptibility in hydrated derivative (right).

Strobel, Pierre, E-mail: pierre.strobel@grenoble.cnrs.f [Institut Neel, CNRS, and Universite Joseph Fourier, B.P. 166, 38042 Grenoble, Cedex 9 (France); Muguerra, Herve [Institut Neel, CNRS, and Universite Joseph Fourier, B.P. 166, 38042 Grenoble, Cedex 9 (France); Hebert, Sylvie [CRISMAT (UMR CNRS 6508), ENSI-Caen, F-14050 Caen Cedex (France); Pachoud, Elise [Institut Neel, CNRS, and Universite Joseph Fourier, B.P. 166, 38042 Grenoble, Cedex 9 (France); CRISMAT (UMR CNRS 6508), ENSI-Caen, F-14050 Caen Cedex (France); Colin, Claire [Institut Neel, CNRS, and Universite Joseph Fourier, B.P. 166, 38042 Grenoble, Cedex 9 (France); Julien, Marc-Henri [Laboratoire de Spectrometrie Physique, UMR CNRS 5588 and Universite Joseph Fourier, 38402 Saint Martin d'Heres (France)

2009-07-15

147

Effect of CeO 2 on the thermoelectric properties of WO 3-based ceramics  

Microsoft Academic Search

The thermoelectric properties of tungsten trioxide (WO3) ceramics doped with cerium dioxide (CeO2) were investigated. The results demonstrated that the addition of CeO2 to WO3 could promote the grain growth and the densification. The magnitude of the electrical conductivity (?) and the absolute value of the Seebeck coefficient (|s|) depended strongly on the CeO2 content. The sample doped with 2.0mol%

Haiqing Wang; Zhongqiu Hua; Shujie Peng; Xiang Dong; Liang Dong; Yu Wang

148

Micro-thermoelectric cooler: interfacial effects on thermal and electrical transport  

Microsoft Academic Search

The flows of heat and electricity in a column-type micro-thermoelectric cooler are analyzed by modeling the various interfacial resistances. Electron (barrier tunneling) and phonon (diffuse mismatch) boundary resistances at the thermoelectric\\/metal interface, and thermal non-equilibrium between electrons and phonons adjacent to this interface (cooling length), increase the thermal conduction resistance and decrease the Seebeck coefficient of the thermoelectric elements. These

Luciana W. da Silva; Massoud Kaviany

2004-01-01

149

Effects of Se substitution on the thermoelectric performance of n-type Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x} skutterudites  

SciTech Connect

Highlights: ? The simple solid state reaction technique was employed to prepare Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x} skutterudites. ? The thermal conductivity decreases gradually with the increasing Se content. ? Doping with moderate Se is an effective way to enhance the thermoelectric performance of Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x}. ? The highest ZT of 1.11 at 800 K is obtained for the Co{sub 4}Sb{sub 11.3}Te{sub 0.58}Se{sub 0.12} sample. -- Abstract: A series of double-substituted Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x} skutterudites have been fabricated by combining the solid state reaction and the spark plasma sintering method, and the effects of Se substitution on the thermoelectric properties are characterized by measurements of the electrical conductivity, the Seebeck coefficient and the thermal conductivity in the temperature range of 300–800 K. Doping Se into the Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x} matrix suppresses the carrier concentration, and the electrical conductivity actually decreases with the Se content. However, moderate Se doping is effective in enhancing the thermoelectric performance of the n-type Co{sub 4}Sb{sub 11.3}Te{sub 0.7?x}Se{sub x}, because of the resulted dramatically decreased thermal conductivity. Analyses indicate that the heightened point-defect scattering induced by Se doping together with the electron–phonon scattering induced by Te doping is responsible for the reduction of lattice thermal conductivity of these compounds.

Duan, Bo [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China)] [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China); Zhai, Pengcheng, E-mail: pczhai@126.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China)] [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China); Liu, Lisheng; Zhang, Qingjie [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China)] [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, No. 122, Luoshi Road, Wuhan 430070 (China)

2012-07-15

150

Advertising Effects and Effectiveness  

Microsoft Academic Search

The results of the application of an integrated econometric time-series model for advertising effectiveness is presented. The model form gives rise to three possible advertising effects: brand loyalty, current effects (both simple and compound) and carryover effects. The inherent nature of these effects is related to the degree of involvement and the affective or cognitive aspects of the purchase decision.

Mike T. Bendixen

1993-01-01

151

The effect of structural vacancies on the thermoelectric properties of (Cu2Te)1-x(Ga2Te3)x  

NASA Astrophysics Data System (ADS)

We have studied the effects of structural vacancies on the thermoelectric properties of the ternary compounds (Cu2Te)1-x(Ga2Te3)x (x=0.5, 0.55, 0.571, 0.6, 0.625, 0.667 and 0.75), which are solid solutions found in the pseudo-binary phase diagram for Cu2Te and Ga2Te3, and possesses tunable structural vacancy concentrations. This materials system is not suitable due to the cost and scarcity of the constituent elements, but the vacancy behavior is well understood and will provide a valuable test case for other systems more suitable from the standpoint of cost and abundance of raw materials, which also possesses these vacancy features, but whose structural characterization is lacking at this stage. We find that the nominally defect free phase CuGaTe2 possess the highest ZT (ZT=S2T/??, where S is the Seebeck coefficient and ? is the electrical resistivity ? is the thermal conductivity and T is the absolute temperature) which approaches 1 at 840 K and seems to continuously increase above this temperature. This result is due to the unexpectedly low thermal conductivity found for this material at high temperature. The low thermal conductivity was caused by strong Umklapp (thermally resistive scattering processes involving three phonons) phonon scattering. We find that due to the coincidentally strong scattering of carriers by the structural defects that higher concentrations of these features lead to poor electrical transport properties and decreased ZT.

Ye, Zuxin; Young Cho, Jung; Tessema, Misle M.; Salvador, James R.; Waldo, Richard A.; Wang, Hsin; Cai, Wei

2013-05-01

152

Effect of Heat Treatment on the Thermoelectric Properties of Bismuth-Antimony-Telluride Prepared by Mechanical Deformation and Mechanical Alloying  

NASA Astrophysics Data System (ADS)

In this work, p-type 20%Bi2Te3-80%Sb2Te3 bulk thermoelectric (TE) materials were prepared by mechanical deformation (MD) of pre-melted ingot and by mechanical alloying (MA) of elemental Bi, Sb, and Te granules followed by cold-pressing. The dependence on annealing time of changes of microstructure and TE properties of the prepared samples, including Seebeck coefficient, electrical resistivity, thermal conductivity, and figure-of-merit, was investigated. For both samples, saturation of the Seebeck coefficient and electrical resistivity were observed after annealing for 1 h at 380°C. It is suggested that energy stored in samples prepared by both MA and MD facilitated their recrystallization within short annealing times. The 20%Bi2Te3-80%Sb2Te3 sample prepared by MA followed by heat treatment had higher a Seebeck coefficient and electrical resistivity than specimens fabricated by MD. Maximum figures-of-merit of 3.00 × 10-3/K and 2.85 × 10-3/K were achieved for samples prepared by MA and MD, respectively.

Lee, Deuk-Hee; Lee, Jae-Uk; Jung, Sung-Jin; Baek, Seung-Hyub; Kim, Ju-Heon; Kim, Dong-Ik; Hyun, Dow-Bin; Kim, Jin-Sang

2014-06-01

153

Thermoelectric properties of electrolessly etched silicon nanowire arrays  

NASA Astrophysics Data System (ADS)

Patterning silicon as nanowires with roughened sidewalls enhances the thermoelectric figure-of-merit ZT by order of magnitude compared to the bulk at 300 K [1]. The enhancement is mainly achieved by the remarkable reduction in the thermal conductivity below 5 W/mK at 300 K with only a negligible effect on the power factor of these nanowires. While the focus remained on understanding the implications of surface disorder on the thermal conductivity, the phonon transport effects on the Seebeck coefficient of these wires remains largely unexplored. We developed an electroless etching technique to generate nanowire arrays (NWAs) with controlled surface roughness, morphology, porosity and doping [2]. We conduct the simultaneous device-level measurements of the Seebeck coefficient and thermal conductivity of the NWAs using frequency domain techniques. We observe that nano-structuring quenches the phonon drag [3] in NWAs thereby reducing the Seebeck coefficient by ˜25% compared to the bulk at degenerate doping levels. Further, we observe that the sidewall roughness greater than 3 nm roughness height lowers the thermal conductivity 75% below the Casimir limit [4] with 10% - 15% increase in Seebeck coefficient. The porous NWAs show thermal conductivity close to the amorphous limit of Si with enhancement in the Seebeck coefficient primarily due to the carrier depletion. References: [1] A. I. Hochbaum et al, Nature 451, 163-167 (2008). [2] K. Balasundaram et. al., Nanotechnology 23, 305304 (2012). [3] C. Herring, Phys. Rev. 96, 1163 (1954). [4] H. G. B. Casimir, Physica 5, 495 (1938).

Sadhu, Jyothi; Tian, Hongxiang; Ma, Jun; Valavala, Krishna; Singh, Piyush; Sinha, Sanjiv

2013-03-01

154

Synthesis and thermoelectric properties of RuO{sub 2} nanorods  

SciTech Connect

We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO{sub 2} nanorods (space group P4{sub 2}/mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.

Music, Denis; Basse, Felix H.-U.; Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Hassdorf, Ralf [Institute of Materials Research, German Aerospace Centre (DLR), D-51147 Cologne (Germany)

2010-07-15

155

Spin density wave order and fluctuations in Mn3Si : A transport study  

NASA Astrophysics Data System (ADS)

We present a comprehensive transport investigation of the itinerant antiferromagnet Mn3Si which undergoes a spin density wave (SDW) order below TN˜21.3K. The electrical resistivity, the thermal conductivity, and the Hall, Seebeck, and Nernst effects exhibit pronounced anomalies at the SDW transition. At temperatures higher than TN our data provide strong evidence for a large fluctuation regime which extends up to ˜200K in the resistivity, the Seebeck effect, and the Nernst effect. From the comparison of our results with other prototype SDW materials, viz., LaFeAsO and chromium, we conclude that many of the observed features are of generic character.

Steckel, Frank; Rodan, Steven; Hermann, Regina; Blum, Christian G. F.; Wurmehl, Sabine; Büchner, Bernd; Hess, Christian

2014-10-01

156

Thermoelectric properties of Yb-filled CoSb3 skutterudites  

NASA Astrophysics Data System (ADS)

Yb-filled skutterudites Yb z Co4Sb12 (z = 0, 0.1, 0.2, 0.3, 0.4) were prepared by encapsulated melting and hot pressing. The filling effects of Yb on the transport and the thermoelectric properties of the skutterudites were examined. In the case of z ? 0.3, a secondary phase (YbSb2) was formed, indicating that the filling fraction limit of Yb was z = 0.2 - 0.3. The intrinsic CoSb3 had a high positive Seebeck coefficient, but Yb-filled CoSb3 exhibited a negative Seebeck coefficient. In the case of z ? 0.1, the maximum absolute value of the Seebeck coefficient was | -231| ?VK-1, and in the case of z ? 0.2, the absolute value of the Seebeck coefficient increased with increasing temperature. The electrical conductivity increased and the Seebeck coefficient decreased with increasing Yb filling content due to the increased carrier concentration. The thermal conductivity was reduced significantly by Yb filling, mainly due to a decrease in the lattice thermal conductivity. Also, the lattice thermal conductivity decreased with increasing Yb filling content, indicating that the phonon scattering was caused by the rattling of Yb fillers in the voids of the skutterudite structure. Yb0.2Co4Sb12 showed the highest figure of merit of 1.0 at 823 K.

Park, Kwan-Ho; Seo, Won-Seon; Shin, Dong-Kil; Kim, Il-Ho

2014-08-01

157

Effect of Nickel Substitution on Defect Chemistry, Electrical Properties, and Dimensional Stability of Calcium-Doped Yttrium Chromite  

SciTech Connect

The effect of nickel substitution on defect chemistry, electrical properties, and dimensional stability of calcium-doped yttrium chromite was studied for use as an interconnect material in high temperature solid oxide fuel cells (SOFCs). The compositions of Y0.8Ca0.2Cr1-xNixO3±? (x=0-0.15), prepared using the glycine nitrate process, showed single phase orthorhombic perovskite structures over a wide range of oxygen partial pressures (10^-17 atm ? pO2 ? 0.21 atm). X-ray diffraction (XRD) analysis indicated that most of the nickel ions replacing chromium ions are divalent and act as acceptor dopants, leading to a substantial increase in conductivity. In particular, the conductivity at 900 degree C in air increased from 10 S/cm to 34 S/cm with 15% nickel substitution, and an increase in charge carrier density was confirmed by Seebeck measurements. A point defect model was derived, and the relationship between electrical conductivity and oxygen partial pressure was successfully fitted into the proposed model. The defect modeling results indicated that nickel substitution improves the stability of calcium-doped yttrium chromite toward reduction and suppresses the oxygen vacancy formation, which results in significantly increased electrical conductivity in reducing environment. The electrical conductivity of Y0.8Ca0.2Cr0.85Ni0.15O3±? at 900 degree C in reducing atmosphere (pO2=10^-17 atm) was 5.8 S/cm, which was more than an order of magnitude higher than that of Y0.8Ca0.2CrO3±? (0.2 S/cm). Improved stability in reducing atmosphere was further confirmed by dilatometry measurements showing reduced isothermal "chemical" expansion, and the isothermal expansion in reducing atmosphere (pO2=10^-17 atm) at 900 degree C decreased from 0.07% for Y0.8Ca0.2CrO3±? to 0.03% for Y0.8Ca0.2Cr0.85Ni0.15O3±?. Based on these results, enhanced electrical performance and mechanical integrity is expected with nickel substitution on calcium-doped yttrium chromite in SOFC operating conditions.

Yoon, Kyung J.; Stevenson, Jeffry W.; Marina, Olga A.

2011-06-30

158

Low effective mass and carrier concentration optimization for high performance p-type Mg2(1-x)Li2xSi0.3Sn0.7 solid solutions.  

PubMed

Mg2Si1-xSnx solid solutions are promising thermoelectric materials for power generation applications in the 500-800 K range. Outstanding n-type forms of these solid solutions have been developed in the past few years with the thermoelectric figure of merit ZT as high as 1.4. Unfortunately, no comparable performance has been achieved so far with p-type forms of the structure. In this work, we use Li doping on Mg sites in an attempt to enhance and control the concentration of hole carriers. We show that Li as well as Ga is a far more effective p-type dopant in comparison to Na or K. With the increasing content of Li, the electrical conductivity rises rapidly on account of a significantly enhanced density of holes. While the Seebeck coefficient decreases concomitantly, the power factor retains robust values supported by a rather high mobility of holes. Theoretical calculations indicate that Mg2Si0.3Sn0.7 intrinsically possesses the almost convergent double valence band structure (the light and heavy band), and Li doping retains a low density of states (DOS) on the top of the valence band, contrary to the Ga doping at the sites of Si/Sn. Low temperature specific heat capacity studies attest to a low DOS effective mass in Li-doped samples and consequently their larger hole mobility. The overall effect is a large power factor of Li-doped solid solutions. Although the thermal conductivity increases as more Li is incorporated in the structure, the enhanced carrier density effectively shifts the onset of intrinsic excitations (bipolar effect) to higher temperatures, and the beneficial role of phonon Umklapp processes as the primary limiting factor to the lattice thermal conductivity is thus extended. The final outcome is the figure of merit ZT ? 0.5 at 750 K for x = 0.07. This represents a 30% improvement in the figure of merit of p-type Mg2Si1-xSnx solid solutions over the literature values. Hence, designing low DOS near Fermi level EF for given carrier pockets can serve as an effective approach to optimize the PF and thus ZT value. PMID:25178356

Zhang, Qiang; Cheng, Long; Liu, Wei; Zheng, Yun; Su, Xianli; Chi, Hang; Liu, Huijun; Yan, Yonggao; Tang, Xinfeng; Uher, Ctirad

2014-11-21

159

Doppler Effect  

NSDL National Science Digital Library

This site offers information on the classical doppler effect, the relativistic doppler effect, aberration, and the transverse doppler effect. It also discusses wave fronts, first-order and second order effect, light-time correction, Galilean transformation, and parallax.

Calvert, J. B.

2005-04-26

160

High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures  

NASA Astrophysics Data System (ADS)

Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.

Nath, Chandrani; Kumar, Ashok; Kuo, Yung-Kang; Okram, Gunadhor Singh

2014-09-01

161

Effect of Fe Substitution on Thermoelectric Properties of Fe x In4- x Se3 Compounds  

NASA Astrophysics Data System (ADS)

Starting from elemental powder mixtures of Fe x In4- x Se3 ( x = 0, 0.05, 0.1, 0.15), polycrystalline In4Se3-based compounds with homogeneous microstructures were prepared by mechanical alloying (MA) and hot pressing (HP). With the increase of x from 0 to 0.15, the electrical resistivity and the absolute value of the Seebeck coefficient increased, while the thermal conductivity first decreased and then increased. The maximal dimensionless figure of merit ZT of 0.44 was obtained for the Fe x In4- x Se3 ( x = 0.05) sample at 723 K.

Li, Gen; Yang, Junyou; Xiao, Ye; Fu, Liangwei; Peng, Jiangying; Deng, Yuan; Zhu, Pinwen; Yan, Haixue

2013-04-01

162

JOURNAL DE PHYSIQUE Colloque C4, supple'ment au no 10, Tome 37, Octobre 1976, page C4-l11 TRANSITION METAL-SEMICONDUCTEUR  

E-print Network

been observed, by electrical resistivity and Seebeck effect measurements, in the Cr~+&Sescompounds when minimale en chrome (E 0'04) et B l'issue d'un refroidissement brutal (trempe a l'eau a partir de 900 OC ult6rieur : sur une pastille frittte nous n'avons jamais pu rtaliser de trempe effective et c'est la

Paris-Sud XI, Université de

163

Solution to the 1-D unsteady heat conduction equation with internal Joule heat generation for thermoelectric devices  

Microsoft Academic Search

Thermoelectric devices are semiconductor devices which are capable of either generating a voltage when placed in between a temperature gradient, exploiting the Seebeck effect, or producing a temperature gradient when powered by electricity, exploiting the Peltier effect. The devices are usually employed in environments with time-varying temperature differences and input\\/output powers. Therefore it becomes important to understand the behaviour of

A. Montecucco; J. R. Buckle; A. R. Knox

164

The Effect of Structural Vacancies on the Thermoelectric Properties of (Cu2Te)1-x(Ga2Te3)x  

SciTech Connect

We have studied the effects of structural vacancies on the thermoelectric properties of the ternary compounds (Cu2Te)1-x(Ga2Te3)x (x = 0.5, 0.55, 0.571, 0.6, 0.625, 0.667 and 0.75), which are solid solutions found in the pseudo-binary phase diagram for Cu2Te and Ga2Te3. This system possesses tunable structural vacancy concentrations. The x= 0.5 phase, CuGaTe2, is nominally devoid of structural vacancies, while the rest of the compounds contain varying amounts of these features, and the volume density of vacancies increases with Ga2Te3 content. The sample with x = 0.5, 0.55, 0.571, 0.6, 0.625 crystallize in the chalcopyrite structure while the x = 0.667 and 0.75 adopt the Ga2Te3 defect zinc blende structure. Strong scattering of heat carrying phonons by structural defects, leads to the reduction of thermal conductivity, which is beneficial to the thermoelectric performance of materials. On the other hand, these defects also scatter charge carriers and reduce the electrical conductivity. All the samples investigated are p-type semiconductors as inferred by the signs of their respective Hall (RH) and Seebeck (S) coefficients. The structural vacancies were found to scatter phonons strongly, while a combination of increased carrier concentration, and vacancies decreases the Hall mobility ( H), degrading the overall thermoelectric performance. The room temperature H drops from 90 cm2/V s for CuGaTe2 to 13 cm2/V s in Cu9Ga11Te21 and 4.6 cm2/V s in CuGa3Te5. The low temperature thermal conductivity decreases significantly with higher Ga2Te3 concentrations (higher vacancy concentration) due to increased point defect scattering which dominate thermal resistance terms. At high temperatures, the dependence of thermal conductivity on the Ga2Te3 content is less significant. The presence of strong Umklapp scattering leads to low thermal conductivity at high temperatures for all samples investigated. The highest ZT among the samples in this study was found for the defect-free CuGaTe2 with ZT ~ 1.0 at 840K.

Ye, Zuxin [GM Research and Development Center; Cho, Jung Y [GM R& D and Planning, Warren, Michigan; Tessema, Misle [GM Research and Development Center; Salvador, James R. [GM R& D and Planning, Warren, Michigan; Waldo, Richard [GM R& D and Planning, Warren, Michigan; Wang, Hsin [ORNL; Cai, Wei [ORNL

2013-01-01

165

INSTITUTE OF PHYSICS PUBLISHING SEMICONDUCTOR SCIENCE AND TECHNOLOGY Semicond. Sci. Technol. 20 (2005) 286289 doi:10.1088/0268-1242/20/3/005  

E-print Network

. Materials and methods Test specimens were prepared from live hornets originally collected from nests of hornet cuticle D Galushko1, N Ermakov2, M Karpovski1, A Palevski1, J S Ishay2 and D J Bergman1 1 Raymond/286 Abstract Seebeck effect (thermo-emf ), thermal conductivity and electrical conductivity of social hornet

Palevski, Alexander

166

On the Use of Thermoelectric (TE) Applications Based on Commercial Modules: The Case of TE Generator and TE Cooler  

Microsoft Academic Search

In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric Generators (TEG) which make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy and is of particular interest for systems of highest reliability or for waste

K. Zorbas; E. Hatzikraniotis; K. M. Paraskevopoulos; Th. Kyratsi

2010-01-01

167

Belgirate, Italy, 28-30 September 2005 ULTRA-LOCAL TEMPERATURE MAPPING WITH AN INTRINSIC THERMOCOUPLE  

E-print Network

THERMOCOUPLE P. Vairaca , B. Cretina , M. Genixa , B. Charlotb , S. Dilhairec , S. Gomesc , G. Tessierc , N-known Seebeck effect through an intrinsic thermocouple made from an EFM conducting tip put in contact reactions and phase transformations. Existing techniques include thermoelectric probes such as thermocouples

168

Progress on Searching Optimal Thermal Spray Parameters for Magnesium Silicide Gaosheng Fu1  

E-print Network

process, thermal spray has been traditionally used for protective barrier coating. In the past decade to be effective way to reduce thermal conductivity which may due to the coating microstructure. VPS result shows coatings. Seebeck coefficient was characterized for thermal sprayed samples and compared with other methods

Zuo, Lei

169

On the magnetotransport of 3D systems in quantizing magnetic field  

NASA Astrophysics Data System (ADS)

The resistivity components of 3D electron gas placed in quantizing magnetic field are calculated taking into account the correction caused by combined action of the Peltier and Seebeck thermoelectric effects. The longitudinal, transverse and the Hall magnetoresistivities exhibit familiar 1/B-period oscillations being universal functions of magnetic field and temperature.

Cheremisin, M. V.

2014-12-01

170

Thermodiffusion in binary liquids: The role of irreversibility Alois Wrger  

E-print Network

[5] and the isotope fractionation in silicate melts [6]. In recent years, thermal diffusion has as driving mechanism and pointing the out the role of the electrolyte Seebeck effect [13--15]. Much less/T of component i is given by the ratio of its chemical potential µi (or partial Gibbs energy) and the absolute

Boyer, Edmond

171

Doppler Effect  

NSDL National Science Digital Library

Doppler effect followed from water waves to sound waves to light waves. Red shift of the universe is also explored. What is doppler effect? It is the change in frequency of a wave for an observer moving relative to the source of the wave. What does that mean? Watch this: moving doppler effect video What does the doppler effect look like in a stationary and moving object? dooppler effect views What does doppler effect have to do with stars and galaxies??? View the following ...

Brown, Mrs.

2010-10-26

172

Doppler Effect  

NSDL National Science Digital Library

Doppler effect followed from water waves to sound waves to light waves. Red shift of the universe is also explored. What is doppler effect? It is the change in frequency of a wave for an observer moving relative to the source of the wave. What does that mean? Watch this: moving doppler effect video What does the doppler effect look like in a stationary and moving object? dooppler effect views What does doppler effect have to do with stars and galaxies??? View the following ...

Clemons, Mrs.

2010-11-10

173

Health Effects  

MedlinePLUS

... significant health impacts on a global scale. Potential Climate Change Health Effects Heat-Related Morbidity and Mortality Asthma, ... Cancer Additional Readings about the Health Effects of Climate Change Frumkin H, Hess J, and Vindigni S. Peak petroleum ...

174

Development of Flexible Micro-Thermo-electrochemical Generators Based on Ionic Liquids  

NASA Astrophysics Data System (ADS)

The unfavourable relationship between electrical and thermal conductivity limits the choice of solid-state materials for thermoelectric generators (TEG). Among ionic liquids (IOL), it appears that a large variety of thermoelectric (TE) materials with promising high Seebeck coefficients have potential for development. Furthermore, the novel solid-on-liquid deposition technology (SOLID) allows the encapsulation of liquid TE materials to create new, highly integrated TEG devices. Following this vision, this paper studies a large number of IOLs looking at TE-relevant parameters such as thermal and electrical conductivity, Seebeck coefficient and temperature-dependent viscosity. We show that positive and negative Seebeck coefficients can be obtained, depending on the molecular structure and the viscosity of the IOL. The properties of single-junction TEGs are presented in terms of I- V characteristics correlated with the IOL properties. We prove that the limiting effect of conversion efficiency is the current density that can be extracted from a device rather than the Seebeck coefficient.

Uhl, Stefanie; Laux, Edith; Journot, Tony; Jeandupeux, Laure; Charmet, Jérôme; Keppner, Herbert

2014-10-01

175

Gauging Effectiveness  

ERIC Educational Resources Information Center

Books by education experts and speakers at national professional conferences have inspired many school leaders to initiate professional learning communities (PLCs). Sustaining them effectively to raise student achievement is another matter. How can one know whether a PLC is moving toward a desired outcome? Measuring effectiveness requires an…

Foord, Kathleen A.; Haar, Jean M.

2012-01-01

176

Chemotherapy Effects  

MedlinePLUS

... our Understanding Chemotherapy guide that discusses chemotherapy side effects. Home Care for the Cancer Patient: Chemotherapy This section of our Home Care guide provides a brief overview of chemotherapy and managing some of its side effects. Chemo Brain The mental cloudiness some people notice ...

177

Doppler Effect  

NSDL National Science Digital Library

In this activity, learners use a tuning fork to explore how the Doppler effect works. They strike the tuning fork to produce a sound, then observe as the tone changes as the fork is swung back and forth. Learners also explore applications of the Doppler effect in technology.

Cosi

2009-01-01

178

Deterministic effects.  

PubMed

Deterministic effects are distinguished from stochastic effects for radiation protection purposes by the following characteristics: both incidence and severity increase as a function of dose after a threshold dose is reached. Cell killing is central to all deterministic effects with the exception of radiation-induced cataracts. The understanding of radiation-induced killing of cells has increased greatly in the last decade with an extraordinarily intense interest in apoptosis. Programmed cell death has long been known to developmental biologists and the importance of cell death has been recognized and quantified by tumor biologists and students of cell kinetics but the coining of a new name and the increase of understanding of the molecular aspects of cell death has stimulated interest. Some cells appear to be very sensitive to radiation and undergo apoptosis, whereas others such as fibroblasts do not with equal frequency. This characteristic, like many others, underlines the genetic differences among cell types. We are reaching a time that there are techniques and the knowledge to apply them to clinical and radiation protection problems. In radiotherapy, success depends on the differential effect between tumor and normal tissues that is obtained. To design the optimum therapy, a profile of both the tumor cells and the cells of the normal tissues that may be at risk would help. The profile would characterize the radiosensitivity and the underlying factors, which could help in the choice of adjunct therapy for tumor and normal tissue. Fibrosis, a common unwanted late effect, appears to be influenced by genetic factors, at least in experimental animals. Techniques are available for treating people as individuals more than ever before, and that must be a good thing to do. Protection against deterministic effects would seem an easy matter but we are uncomfortably ignorant of the precise effect of protracted low-dose irradiation on tissues, such as the bone marrow and the testis, important features of risk in space. Entering the new century, it may be timely to classify radiation effects, as Radiation Effects Research Foundation (RERF) has done, into cancer, genetic effects, and noncancer effects. The recognition in the atomic-bomb survivors of noncancer effects at doses on the order of 0.5 Sv (half the dose level considered a threshold in earlier studies) should stimulate interest in deterministic effects. PMID:11281201

Fry, R J

2001-04-01

179

Effect of rare earth radius and concentration on the structural and transport properties of doped Mn Zn ferrite  

NASA Astrophysics Data System (ADS)

Dielectric constant ( ?'), AC conductivity ( ?), and seebeck coefficient ( S) have been measured for the ferrite samples of the general formula Mn 0.5Zn 0.5R yFe 2O 4; where R=Dy, Gd, Sm, Ce, and La prepared by standard ceramic technique and sintered at 1200 °C with a heating rate 4 °C/min. X-ray diffractograms show that all samples posses the spinel structure with the appearance of small peaks representing secondary phases. There is a lowering in the porosity starting after Sm-doped samples due to the presence of the secondary phases, which limits the grain growth. Due to seebeck measurements the manganese-zinc (Mn-Zn) ferrite doped with the rare earth has been classified as P-type semiconductors. It is possible to increase the electrical resistivity by using a small quantity of Dy 3+ ions substitutions owing to the structural heterogeneity generated by the insulating intergranular layers. The isolation of the grains is the most promising approaches for further reduction in the eddy current losses at the operating frequencies.

Ateia, E.; Ahmed, M. A.; El-Aziz, A. K.

2007-04-01

180

Effects of Bi on the thermoelectric properties of Mg2Si-Mg2Ge solid solutions  

NASA Astrophysics Data System (ADS)

Mg2Si1- x Ge x :Bi m (0.3 ? x ? 0.7, m = 0 or 0.02) solid solutions were synthesized by using a solid-state reaction (SSR) and were consolidated by hot pressing (HP). In the case of the undoped Mg2Si1- x Ge x specimens, the electrical conduction changed from n-type to p-type at room temperature for x ? 0.7 due to the intrinsic properties of Mg2Ge. The electrical conductivity rapidly increased with increasing temperature, indicating a non-degenerate semiconducting behavior, and decreased with increasing Ge content. However, all Bi-doped Mg2Si1- x Ge x solutions showed n-type conduction. The carrier concentration was increased from 4.0 × 1017 to 1.9 × 1020 cm-3 by Bi doping, and the electrical conductivity was increased from 7.3 × 10 to 4.3 × 104 Sm-1. The absolute value of the Seebeck coefficient increased with increasing temperature, and the Seebeck coefficient ranged from -91 to -224 ?VK-1 for the Bi-doped specimens. Bi doping reduced the thermal conductivities of the Mg2Si1- x Ge x solid solutions at temperatures above 723 K. Mg2Si0.7Ge0.3:Bi0.02 exhibited a maximum dimensionless figure-of-merit of 0.79 at 823 K.

You, Sin-Wook; Shin, Dong-Kil; Kim, Il-Ho

2014-09-01

181

Effect of Y doping on magnetic and transport properties of La0.7Sr0.3CoO3  

NASA Astrophysics Data System (ADS)

The temperature variation of magnetization, resistivity and thermo electric power of undoped and Y-doped La0.7Sr0.3CoO3 samples have been investigated. Y-doping decreases the magnetization possibly due to the spin state transition of Co-ions. The low temperature conduction in (La1-yYy)0.7Sr0.3CoO3 is consistent with the variable range hopping. With Y doping, value of the Seebeck coefficient increases, as Y doping decreases bandwidth and increases distortion.

Dwivedi, G. D.; Shukla, K. K.; Shahi, P.; Jha, O. K.; Ghosh, A. K.; Nigam, A. K.; Chatterjee, Sandip

2013-02-01

182

Psychopharmaceuticals: effects and side effects  

PubMed Central

Drugs which affect psychological behaviour are being used in vast amounts nowadays, with, in all too many cases, but scant regard for their exact uses or possible side effects. This article contains a clinical classification of these drugs, followed by an account of their principal side effects and the means of obviating them. PMID:14409889

Kline, Nathan S.

1959-01-01

183

Doppler Effect  

NSDL National Science Digital Library

- The Doppler Effect explains why we hear a sonic boom when an airplane flies faster than the speed of sound. - Applying the Doppler Effect is how we have Doppler Radar used to track weather. - The Doppler Effect can be applied to outerspace and it evidence that the universe is expanding. Sound is energy traveling through a medium. A medium can be a gas, liquid, or solid. Therefore sound can not travel in outerspace since it is a vacuum which means there is nothing not even air. Energy traveling through a medium or even a vacuum is considered a wave. ...

Leet, Mr.

2008-03-16

184

Effective Parenting  

MedlinePLUS

... parents? There is a whole history to your parent-child relationship that began at the moment your youngster was ... effectively, so they will not interfere with your parent-child relationships. For example, if you are like many parents, ...

185

Health Effects  

MedlinePLUS

... of Cannabis sativa or cannabis indica—the hemp plant Health Effects Acute Heightened sensory perception; euphoria, followed ... addiction. Street Opioids (Heroin, Opium) Processed from poppy plants; a white or brownish powder or black sticky ...

186

Effects and Effectiveness of Telemedicine  

PubMed Central

The use of telemedicine has recently undergone rapid growth and proliferation. Although the feasibility of many applications has been tested for nearly 30 years, data concerning the costs, effects, and effectiveness of telemedicine are limited. Consequently, the development of a strategy for coverage, payment, and utilization policy has been hindered. Telemedicine continues to expand, and pressure for policy development increases in the context of Federal budget cuts and major changes in health service financing. This article reviews the literature on the effects and medical effectiveness of telemedicine. It concludes with several recommendations for research, followed by a discussion of several specific questions, the answers to which might have a bearing on policy development. PMID:10153466

Grigsby, Jim; Kaehny, Margaret M.; Sandberg, Elliot J.; Schlenker, Robert E.; Shaughnessy, Peter W.

1995-01-01

187

[Effective delegation].  

PubMed

Ninety-seven percent of middle level managers feel they face work overload. The source of this problem may lie in a failure to delegate tasks effectively. If a manager does not effectively delegate, he/she is more likely to report fatigue, stress and depression. Conversely, effectively delegating tasks will improve overall job quality, professional growth in subordinates and cooperation within the team. While it is necessary for managers to delegate tasks effectively, few can be considered to be good natural 'delegators'. Learning and training is necessary for managers to develop the necessary confidence and maturity. This article describes the definitions, purpose and benefits of delegation; factors related to effective delegation; strategies related to successful delegation and skills related to performing cross-cultural delegations. Such issues have seldom been addressed in previous articles. Moreover, nursing implications and suggested applications in nursing practice, education, management and research are mentioned. This article is intended to provide directions to nursing managers and subordinates to promote delegation knowledge and skills. PMID:19051179

Fang, Li; Hung, Chich-Hsiu

2008-12-01

188

Photoelectric Effect  

NSDL National Science Digital Library

This is a series of simulations of aspects of the photoelectric effect. There is an animation of the experiment with four choices of incident radiation - low and high intensity "red", to represent low energy light and low and high intensity "blue" to represent higher energy light. Electron production is animated and there is an ammeter to simulate current flow. Additional simulations show the effect of light frequency and intensity. There is a link to a spreadsheet that allows students to choose a sample from among five metals. The spreadsheet includes several questions to be answered after working through the materials.

189

Interpersonal Effectiveness  

NSDL National Science Digital Library

Interpersonal Effectiveness provides participants with an opportunity to develop their interpersonal skills through interactive exercises conducted in a team setting. Debriefing these exercises with all members of the class helps ensure that the exercises translate into personal and interpersonal learning for the participants. After completing this module, students should be able to identify the principles of good teamwork and effective communication and demonstrate those skills during a series of interactive exercises. Note: This module is part of a modularized manufacturing technology curriculum created by the PSCME, found at www.pscme.org/educators.html.

Alston, Michele; King, John

2010-07-26

190

Sleeper Effects  

ERIC Educational Resources Information Center

Early experience preserves and refines many capabilities that emerge prenatally. Here we describe another role that it plays--establishing the neural substrate for capabilities that emerge at a much later point in development. The evidence comes from sleeper effects: permanent deficits when early experience was absent in capabilities that normally…

Maurer, Daphne; Mondloch, Catherine J.; Lewis, Terri L.

2007-01-01

191

Effective Evaluation  

ERIC Educational Resources Information Center

Principals know that effective teachers are the greatest school-based contributors to improved student outcomes. What is not always clear is how principals can help teachers adapt their instructional practices to the increasingly diverse learning styles they find in their classrooms. Teacher evaluation practices are typically not seen as a tool…

Oliva, Michelle; Mathers, Carrie; Laine, Sabrina

2009-01-01

192

System Effectiveness  

SciTech Connect

An effective risk assessment system is needed to address the threat posed by an active or passive insider who, acting alone or in collusion, could attempt diversion or theft of nuclear material. It is critical that a nuclear facility conduct a thorough self-assessment of the material protection, control, and accountability (MPC&A) system to evaluate system effectiveness. Self-assessment involves vulnerability analysis and performance testing of the MPC&A system. The process should lead to confirmation that mitigating features of the system effectively minimize the threat, or it could lead to the conclusion that system improvements or upgrades are necessary to achieve acceptable protection against the threat. Analysis of the MPC&A system is necessary to understand the limits and vulnerabilities of the system to internal threats. Self-assessment helps the facility be prepared to respond to internal threats and reduce the risk of theft or diversion of nuclear material. MSET is a self-assessment or inspection tool utilizing probabilistic risk assessment (PRA) methodology to calculate the system effectiveness of a nuclear facility's MPC&A system. MSET analyzes the effectiveness of an MPC&A system based on defined performance metrics for MPC&A functions based on U.S. and international best practices and regulations. A facility's MC&A system can be evaluated at a point in time and reevaluated after upgrades are implemented or after other system changes occur. The total system or specific subareas within the system can be evaluated. Areas of potential performance improvement or system upgrade can be assessed to determine where the most beneficial and cost-effective improvements should be made. Analyses of risk importance factors show that sustainability is essential for optimal performance. The analyses reveal where performance degradation has the greatest detrimental impact on total system risk and where performance improvements have the greatest reduction in system risk. The risk importance factors show the amount of risk reduction achievable with potential upgrades and the amount of risk reduction actually achieved after upgrades are completed. Applying the risk assessment tool gives support to budget prioritization by showing where budget support levels must be sustained for MC&A functions most important to risk. Results of the risk assessment are also useful in supporting funding justifications for system improvements that significantly reduce system risk.

Powell, Danny H [ORNL] [ORNL; Elwood Jr, Robert H [ORNL] [ORNL

2011-01-01

193

Pseudo-direct bandgap transitions in silicon nanocrystals: effects on optoelectronics and thermoelectrics.  

PubMed

While silicon nanostructures are extensively used in electronics, the indirect bandgap of silicon poses challenges for optoelectronic applications like photovoltaics and light emitting diodes (LEDs). Here, we show that size-dependent pseudo-direct bandgap transitions in silicon nanocrystals dominate the interactions between (photoexcited) charge carriers and phonons, and hence the optoelectronic properties of silicon nanocrystals. Direct measurements of the electronic density of states (DOS) for different sized silicon nanocrystals reveal that these pseudo-direct transitions, likely arising from the nanocrystal surface, can couple with the quantum-confined silicon states. Moreover, we demonstrate that since these transitions determine the interactions of charge carriers with phonons, they change the light emission, absorption, charge carrier diffusion and phonon drag (Seebeck coefficient) in nanoscaled silicon semiconductors. Therefore, these results can have important implications for the design of optoelectronics and thermoelectric devices based on nanostructured silicon. PMID:25367148

Singh, Vivek; Yu, Yixuan; Sun, Qi-C; Korgel, Brian; Nagpal, Prashant

2014-12-21

194

Magnetothermoelectric effects in Fe1+dTe1-xSex  

NASA Astrophysics Data System (ADS)

We report data on resistivity as well as Hall, Seebeck and Nernst coefficients for the Fe1+dTe1-xSex single crystals with x = 0, 0.39, and 0.40. The parent compound Fe1.04Te exhibits a Fermi surface reconstruction at T = 61 K, which is ascribed to the onset of the antiferromagnetic order. Two very closely doped samples: Fe1.01Se0.39Te0.61 (Se39) and Fe1.01Se0.4Te0.6 (Se40) are superconductors with Tc = 13.4 K and 13.9 K, respectively. Properties of these two single crystals are almost identical at high temperatures, but start to diverge below T 80 K. Despite there is no magnetic transition in neither Se39 nor Se40, the observed differences seem to be a consequence of varying with selenium content spin correlations.

Matusiak, Marcin; Conder, Kazimierz

2012-02-01

195

Blazhko Effect  

NASA Technical Reports Server (NTRS)

The cause of the Blazhko effect, the long-term modulation of the light and radial velocity curves of some RR Lyr stars, is still not understood. The observational characteristics of the Blazhko effect are discussed. Some preliminary results are presented from two recent campaigns to observe RR Lyr, using the International Ultraviolet Explorer along with ground-based spectroscopy and photometry, throughout a pulsation cycle, at a variety of Blazhko phases. A set of ultraviolet light curves have been generated from low dispersion IUE spectra. In addition, the (visual) light curves from IUE's Fine Error Sensor are analyzed using the Fourier decomposition technique. The values of the parameters Psi(sub 21) and R(sub 21) at different Blazhko phases of RR Lyr span the range of values found for non-Blazhko variables of similar period.

Teays, Terry

1996-01-01

196

Effectiveness performance  

E-print Network

Effectiveness of Remote Cache in a NUMA System Don DeSota, Sequent Computers Ruth Forester, Sequent Computers #12; . In NUMA systems remote accesses will degrade performance . A level 3 cache for remote Database cust1 NUMA 8 PPro 32M DB­A cust2 NUMA 8 PPro 32M DB­A cust3­1 NONNUMA 4 PPro 32M DB­A cust3

Zilles, Craig

197

Effective Presentations  

PubMed Central

Where the purpose of presentations is to inform, effective delivery is important to ensure that audiences receive the educational message. We offer six suggestions: introduce the topic in an interesting way; speak loudly enough; do not read; involve the audience actively; respect the attention span of the audience; and limit the amount of content. We conclude that the skills of live public presentation can be learned, but that the art of presentation is innate. Imagesp2063-ap2064-a PMID:21233951

Spooner, H. James; Swanson, Richard W.

1990-01-01

198

Ripple Effects  

E-print Network

policies and practices might have on producers? incomes and water savings, as well as the ripple effects on the regional economy. Drs. Steve Amosson of Texas Cooperative Extension in Amarillo, Lal K. Almas of West Texas A&M University, Jeff Peterson... income and aquifer-saturated thickness for each county in the study. Almas, assistant professor of agricultural business and economics, said the optimization model determines the number of irrigated acres for each crop that maximizes the value...

Wythe, Kathy

2006-01-01

199

Compton Effect  

NSDL National Science Digital Library

The Compton Effect model simulates the the scattering of light off of an electron, the Compton effect. Compton used the idea that light behaves like a particle to explain light-electron (photon-electron) scattering. He used the relation for the energy and momentum of the photon and the relativistic expression for the energy of the electron, and applied relativistic energy and momentum conservation for the collision. The wavelength shift of the light depend on the angle of the scattered photon (and the electron). By changing the scattering angle in the simulation, the angle of the scattered photon changes according to Compton's equation. The panel on the left shows the experimental set up, while the panel on the right shows the resulting photon wavelength from the scattering. In a typical Compton experiment, light is scattered off of the electrons in an atom, and there is little scattering due to the more tightly held electrons while there is more scattering due to the less tightly held electrons. This is what is responsible for the two peak distribution shown. The Compton Effect model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_qm_compton.jar file will run the program if Java is installed.

Palop, Jose I.

2010-12-12

200

Effects of Thermal Annealing on the Thermoelectric and Optical Properties of SiO2/SiO2+Cu Nanolayer Thin Films  

NASA Astrophysics Data System (ADS)

We have prepared multi-nanolayer superlattice thin-film systems comprising 36 alternating layers of SiO2 and SiO2+Cu nanolayers, of total thickness approximately 300 nm, by magnetron direct current-radio frequency sputtering. To modify their thermoelectric and optical properties, the films were placed in a furnace for annealing at temperatures between 500°C and 700°C, in air, for 1 h, to form quantum nano-dots and/or quantum clusters. Atomic force microscopy was used to analyze the surface of the thin-film systems. The thermoelectric and optical properties of the systems were characterized by study of ultraviolet-visible-near infrared absorption, fluorescence, and Raman spectroscopy, and by measurement of Seebeck coefficients. Seebeck coefficients increased from -70 ?V/K to -100 ?V/K when the temperature was increased from 0°C to 700°C. Optical absorption spectra showed that formation of nano-dots and/or nano-clustering also occurred as the temperature was increased. Thermal annealing affected the optical and thermal properties of the multi-nanolayer thermoelectric thin-film systems in the positive direction.

Budak, S.; Baker, M.; Lassiter, J.; Smith, C.; Muntele, C.; Johnson, R. B.

2014-09-01

201

Piezoelectric Effect  

NSDL National Science Digital Library

In this activity, by the Concord Consortium's Molecular Literacy project, students explore the piezoelectric effect, which is the conversion between electricity and mechanical motion. The model used in this activity shows this conversion and users can manipulate the model to change the voltage and observe changes to a crystal. The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In these activities, students are allowed to explore at their own pace in a digital environment full of demonstrations, illustrations, and models they can manipulate. In addition to the activity, visitors will find an overview of the activity and central and key concepts.

2008-10-23

202

Erosion Effects  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.

2003-01-01

203

Effective committees.  

PubMed

A committee is a group of people officially delegated to perform a function, such as investigating, considering, reporting, or acting on a matter. Some committees function like task forces and work on specific, time-limited projects. When the work is finished, the committees are no longer needed. These committees are called ad hoc committees. Other committees are standing committees. They are created by the standing orders, rules, by-laws, or regulations of an organization and exist and function indefinitely (eg, finance, membership, education, nomination). Both types of committees can form subcommittees if the workloads are heavy or complex in nature. Committees can be among the most important working forces of an organization. They serve as work units of the organization, taking work and breaking it into meaningful and manageable chunks. They efficiently carry out the work of the organization. Committee work should be a rewarding experience for both the members and the organization. Committees represent, involve, and serve members, as well as provide an important training ground for future leaders of an organization. New or inexperienced members can gain valuable insight into an organization and develop confidence by serving on committees. There are several key elements of effective committees, including (1) a clear, written purpose; (2) an effective committee chair; (3) thoughtfully appointed members; and (4) well-run meetings. PMID:22386164

Collins, Jannette

2012-03-01

204

Sputter deposited p-type nickel oxide thin films as an anode buffer layer in organic solar cells  

Microsoft Academic Search

P-type NiO thin films were prepared by magnetron sputtering and their characteristic properties were investigated with varying oxygen gas ratio in sputtering ambient. From the measurements of Hall effect and Seebeck coefficient, the films were confirmed to be of p-type conduction. NiO films were applied as the anode buffer layer between ITO and active layer in organic solar cells. Effects

Dong-Ho Kim; Jae-Wook Kang; Hye-Ri Kim; Yong-Jin Kang; Sun-Young Park; Yong-Soo Jeong

2011-01-01

205

Dimensional Analysis of Thermoelectric Modules Under Constant Heat Flux  

NASA Astrophysics Data System (ADS)

Thermoelectric power generation is examined in the case of radiative heating. A constant heat flux is assumed in addition to consideration of the Seebeck effect, Peltier effect, and Joule heating with temperature-dependent material properties. Numerical evaluations are conducted using a combination of the finite-volume method and an original simultaneous solver for the heat transfer, thermoelectric, and electric transportation phenomena. Comparison with experimental results shows that the new solver could work well in the numerical calculations. The calculations predict that the Seebeck effect becomes larger for longer thermoelectric elements because of the larger temperature difference. The heat transfer to the cold surface is critical to determine the junction temperatures under a constant heat flux from the hot surface. The negative contribution from Peltier cooling and heating can be minimized when the current is smaller for longer elements. Therefore, a thicker TE module can generate more electric power even under a constant heat flux.

Suzuki, Ryosuke O.; Fujisaka, Takeyuki; Ito, Keita O.; Meng, Xiangning; Sui, Hong-Tao

2014-08-01

206

Spin current generation from sputtered Y3Fe5O12 films  

NASA Astrophysics Data System (ADS)

Spin current injection from sputtered yttrium iron garnet (YIG) films into an adjacent platinum layer has been investigated by means of the spin pumping and the spin Seebeck effects. Films with a thickness of 83 and 96 nanometers were fabricated by on-axis magnetron rf sputtering at room temperature and subsequent post-annealing. From the frequency dependence of the ferromagnetic resonance linewidth, the damping constant has been estimated to be (7.0 ± 1.0) × 10-4. Magnitudes of the spin current generated by the spin pumping and the spin Seebeck effect are of the same order as values for YIG films prepared by liquid phase epitaxy. The efficient spin current injection can be ascribed to a good YIG|Pt interface, which is confirmed by the large spin-mixing conductance (2.0 ± 0.2) × 1018 m-2.

Lustikova, J.; Shiomi, Y.; Qiu, Z.; Kikkawa, T.; Iguchi, R.; Uchida, K.; Saitoh, E.

2014-10-01

207

Thermoelectric properties of magnesium silicide fabricated using vacuum plasma thermal spray  

NASA Astrophysics Data System (ADS)

The thermoelectric properties of magnesium silicide samples prepared by Vacuum Plasma Spray (VPS) are compared with those made from the conventional hot press method using the same feedstock powder. Thermal conductivity, electrical conductivity, Seebeck coefficient, and figure of merit are characterized from room temperature to 700 K. X-ray diffraction and scanning electron microscopy of the samples are obtained to assess how phase and microstructure influence the thermoelectric properties. Carrier concentration and Hall mobility are obtained from Hall Effect measurements, which provide further insight into the electrical conductivity and Seebeck coefficient mechanisms. Low-temperature electrical conductivity measurements suggest a 3D variable range hopping effect in the samples. VPS samples achieved a maximum ZT = 0.16 at 700 K, which is around 30% of the hot press sample ZT = 0.55 at 700 K using the same raw powder. The results suggest that thermal spray is a potential deposition technique for thermoelectric materials.

Fu, Gaosheng; Zuo, Lei; Longtin, Jon; Nie, Chao; Gambino, Richard

2013-10-01

208

Magnetic and transport properties of delafossite oxides CuCr 1 - x ( Mg , Ca ) x O 2  

Microsoft Academic Search

We investigated an effect of Mg2+ or Ca2+ substitution at the Cr sites on magnetic and transport properties in CuCrO2. In the case of CuCr1-xMgxO2 polycrystals, the physical properties such as resistivity, magnetization, Seebeck coefficient and specific heat systematically varied with the increase of Mg content x, which indicated that holes were doped into them by substitution of Mg2+ ions

T. Okuda; T. Onoe; Y. Beppu; N. Terada; T. Doi; S. Miyasaka; Y. Tokura

2007-01-01

209

Magnetic and transport properties of delafossite oxides CuCr1-x(Mg,Ca)O2  

Microsoft Academic Search

We investigated an effect of Mg or Ca substitution at the Cr sites on magnetic and transport properties in CuCrO2. In the case of CuCr1-xMgO2 polycrystals, the physical properties such as resistivity, magnetization, Seebeck coefficient and specific heat systematically varied with the increase of Mg content x, which indicated that holes were doped into them by substitution of Mg ions

T. Okuda; T. Onoe; Y. Beppu; N. Terada; T. Doi; S. Miyasaka; Y. Tokura

2007-01-01

210

Influence of the rare-earth element on the effects of the structural and magnetic phase transitions in CeFeAsO, PrFeAsO, and NdFeAsO  

SciTech Connect

We present results of transport and magnetic properties and heat capacity measurements on polycrystalline CeFeAsO, PrFeAsO and NdFeAsO. These materials undergo structural phase transitions, spin density wave-like magnetic ordering of small moments on iron and antiferromagnetic ordering of rare-earth moments. The temperature dependence of the electrical resistivity, Seebeck coefficient, thermal conductivity, Hall coefficient and magnetoresistance are reported. The magnetic behavior of the materials have been investigated using Moessbauer spectroscopy and magnetization measurements. Transport and magnetic properties are affected strongly by the structural and magnetic transitions, suggesting significant changes in the band structure and/or carrier mobilities occur, and phonon-phonon scattering is reduced upon transformation to the low-temperature structure. Results are compared with recent reports for LaFeAsO, and systematic variations in properties as the identity of Ln is changed are observed and discussed. As Ln progresses across the rare-earth series from La to Nd, an increase in the hole contributions to the Seebeck coefficient and increases in magnetoresistance and the Hall coefficient are observed in the low-temperature phase. Analysis of hyperfine fields at the iron nuclei determined from Moessbauer spectra indicates that the moment on Fe in the orthorhombic phase is nearly independent of the identity of Ln, in apparent contrast to reports of powder neutron diffraction refinements.

McGuire, Michael A [ORNL; Hermann, Raphael P. [Forschungszentrum Julich, Julich, Germany; Safa-Sefat, Athena [ORNL; Sales, Brian C [ORNL; Jin, Rongying [ORNL; Mandrus, David [ORNL; Grandjean, F. [University of Liege, Belgium; Long, Gary J. [University of Missouri, Rolla

2009-01-01

211

Effects of MeV Si ions bombardment on the thermoelectric generator from SiO 2/SiO 2 + Cu and SiO 2/SiO 2 + Au nanolayered multilayer films  

NASA Astrophysics Data System (ADS)

The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO 2/SiO 2 + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO 2/SiO 2 + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO 2, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

Budak, S.; Chacha, J.; Smith, C.; Pugh, M.; Colon, T.; Heidary, K.; Johnson, R. B.; Ila, D.

2011-12-01

212

Structural and Thermoelectric Properties of Nanocrystalline Bismuth Telluride Thin Films Under Compressive and Tensile Strain  

NASA Astrophysics Data System (ADS)

To investigate the effect of strain on bismuth telluride films, we applied different compressive and tensile strains to thin films by changing the bending radius of a flexible substrate so the strain ranged from -0.3% (compressive) to +0.3% (tensile). The structural properties of the strained thin films, composed of nanosized grains, were analyzed by x-ray diffraction and scanning electron microscopy. For all samples the main peak was the (015) diffraction peak; crystal orientation along the (015) growth direction was slightly enhanced by application of compressive strain. The thermoelectric properties of strained bismuth telluride thin films were evaluated by measurement of electrical conductivity, Seebeck coefficient, and power factor. The magnitude and direction of the applied strain did not significantly affect the power factor, because when the strain changed from compressive to tensile the electrical conductivity increased and the absolute Seebeck coefficient decreased.

Kusagaya, K.; Hagino, H.; Tanaka, S.; Miyazaki, K.; Takashiri, M.

2014-11-01

213

Ecological Effects in Malaria Vaccine Effectiveness in  

E-print Network

Ecological Effects in Malaria Vaccine Effectiveness in Lilongwe, Malawi Cameron Taylor B component to a GlaxoSmithKline phase III trial vaccine trial so that researchers can better understand distribution and the ecological effects of both malaria transmission intensity and vaccine efficacy

Doyle, Martin

214

Side Effects of Chemotherapy  

MedlinePLUS

... PCF Spotlight Glossary African American Men Living with Prostate Cancer Side Effects of Chemotherapy Side Effects Urinary Dysfunction ... side effects of docetaxel as used to treat prostate cancer are VERY different and less severe than the ...

215

Mercury: Health Effects  

MedlinePLUS

... toxicological profile for mercury . Top of page Elemental mercury effects Elemental (metallic) mercury primarily causes health effects ... 0370.htm . Top of page Effects of other mercury compounds (inorganic and organic) High exposures to inorganic ...

216

Communicating Effectively PDF  

Cancer.gov

Effective communication is essential for the delivery of quality cancer palliative care. And yet, healthcare providers often lack the skills to communicate effectively with their patients and families.

217

High-temperature resistivity and thermoelectric properties of coupled substituted Ca3Co2O6  

NASA Astrophysics Data System (ADS)

Polycrystalline samples of Ca3-xNaxCo2-xMnxO6 (x=0.0-0.5) have been prepared by the sol-gel cum combustion method using sucrose in order to investigate the effects of the coupled substitution of Na and Mn on Ca and Co sites on the transport properties of Ca3Co2O6(Co326). The products were characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction (XRD), thermogravimetry (TGA), differential thermal analysis and scanning electron microscopy. XRD patterns reveal the formation of single-phase products up to x=0.5. Coupled substitution increases the solubility of both Na and Mn on Ca and Co sites, respectively, in contrast to the limited solubility of Na and Mn (x=0.2) when separately substituted. TGA confirms the formation of the Ca3Co2O6 phase at temperatures ~720 °C. The grain size of the parent and substituted products is in the range 150-250 nm. Electrical resistivity and Seebeck coefficient were measured in the temperature range 300-800 K. Resistivity shows semiconducting behavior for all the compositions, particularly in the low-temperature regime. The Seebeck coefficient increases with temperature throughout the measured temperature range for all compositions. The maximum Seebeck coefficient (200 ?V K-1) is observed for x=0.5 at 825 K, and this composition may be optimal for high-temperature thermoelectric applications.

Senthilkumar, Meenakshisundaram; Vijayaraghavan, Rajagopalan

2009-01-01

218

Thermoelectric Properties of Double-Filled p-Type La1-z Yb z Fe4-x Co x Sb12 Skutterudites  

NASA Astrophysics Data System (ADS)

La and Yb double-filled p-type skutterudites (La1-z Yb z Fe4-x Co x Sb12; 0.25 ? z ? 0.75 and 0.5 ? x ? 1) were synthesized by encapsulated melting and homogenized by use of heat treatment. It was apparent from the positive signs of the Seebeck coefficient and the Hall coefficient that all specimens had p-type characteristics. The carrier concentration decreased with charge compensation. The thermal conductivity and the electrical conductivity decreased and the Seebeck coefficient increased with increasing substitution of Co for Fe. However, the carrier concentration was increased by increasing the Yb filling ratio. Electrical conductivity increased and the Seebeck coefficient decreased with increasing Yb filling, because the electron valence of Yb2+ was lower than that of La3+. The thermal conductivity decreased with charge compensation, and the lattice thermal conductivity decreased with increasing Yb filling. Yb was more effective than La at reducing lattice thermal conductivity. The power factor (PF) and dimensionless figure of merit (ZT) increased with increasing temperature up to a specific temperature. The maximum PF = 2.81 mW/mK2 at 823 K was obtained for La0.75Yb0.25Fe3.5Co0.5Sb12 and the maximum ZT = 0.74 at 723 K was achieved for La0.5Yb0.5Fe3CoSb12.

Joo, Gyeong-Seok; Shin, Dong-Kil; Kim, Il-Ho

2014-09-01

219

Potential Chemotherapy Side Effects  

PubMed Central

Background In order to determine the number of short-term side effects and late effects discussed during an informed consent conference (ICC) after the diagnosis of acute leukemia, we observed the occurrence(s) and the ratio between short-term side effects versus late effects during an ICC. Procedure ICC(s) of childhood leukemia trials were audio-taped at six different study sites. The side effects mentioned during each of these ICC(s) were coded and analyzed. Results One hundred and forty cases were reviewed, from which we coded a total of 3173 acute side effects and 242 late effects. The mean total side effects mentioned during each ICC was 24 (range 5-47). The number of late effects coded were significantly less than acute side effects. We also found that the duration of ICC(s) was positively correlated with the number of side effects mentioned. In addition, the frequency of total side effects mentioned was independent of patient or parent demographic factors. Conclusions Our results show that acute side effects are often mentioned but the discussion of late effects is much less frequent in the initial ICC(s). Careful consideration regarding the ratio of acute and late effects that are communicated to parents in the context of the informed consent conference may facilitate parental understanding of clinically relevant side effects. PMID:19101994

Ramirez, Lisa Ysela; Huestis, Samantha E; Yi Yap, Tsiao; Zyzanski, Stephen; Drotar, Dennis; Kodish, Eric

2008-01-01

220

AHSGE Cause and Effect  

NSDL National Science Digital Library

Cause and Effect practice to build skill knowledge for the reading portion of the graduation exam. Complete the Cause and Effect activities at your pace . Cause and Effect Match , Cause and Effect Mini Lesson and Game , What s the Cause?? Quiz . ...

Ufomadu, Ms.

2013-06-13

221

New type of thermoelectric conversion of energy by semiconducting liquid anisotropic media  

E-print Network

The paper describes preliminary investigations of a new effect in conducting anisotropic liquids, which leads to thermoelectric conversion of energy. Nematic liquid crystals with semiconducting dopes are used. A thermoelectric figure of merit ZT = 0.2 is obtained in experiments. The effect can be explained by assuming that the thermocurrent in semiconducting nematics, in contrast to the Seebeck effect, is a nonlinear function of the temperature gradient and of the temperature itself. Though the discovered effect has to be further investigated, the data obtained suggest that it can be effectively used in alternative energy engineering.

Sergey I. Trashkeev; Alexey N. Kudryavtsev

2012-11-02

222

Power Generator Modules of Segmented Bi2Te3 and ErAs:(InGaAs)1-x(InAlAs)x  

E-print Network

by vari- able-temperature measurements of thermal conductivity, electrical conduc- tivity, and Seebeck coefficient, electrical con- ductivity, thermal conductivity, and absolute temperature, respectively of a large Seebeck coefficient, low thermal conductivity, and possibly high electrical conductivity can

223

CaMn1-x NbxO3 (x e 0.08) Perovskite-Type Phases As Promising New High-Temperature n-Type Thermoelectric Materials  

E-print Network

of their high-temperature thermoelectric properties (Seebeck coefficient, electrical resistivity, and thermal phases exhibit large absolute Seebeck coefficient and low electrical resistivity values, resulting maintenance-free, since electricity is generated (i) without involvement of chemical reactions compared

224

Medications and Side Effects  

MedlinePLUS

... medication. WHEN & HOW SEVERE (1= NOT VERY/ SIDE EFFECT 5 = EXTREMELY)SUGGESTIONS FOR COPING Lack of energy/ ... doctor. WHEN & HOW SEVERE (1= NOT VERY/ SIDE EFFECT 5 = EXTREMELY)SUGGESTIONS FOR COPING Anxiety I Ask ...

225

Aeroelastic Thermal Effects.  

National Technical Information Service (NTIS)

The adverse effect of increasing temperature on the stability of turbomachinery airfoils was long recognized but remains today one that is not fully understood. The quantitative effect on the reduced frequency parameter, k = omega c/V, which was experimen...

J. D. Jeffers

1988-01-01

226

Managing Physical Effects  

Cancer.gov

Browse a list of common side effects of cancer or cancer treatment with links to practical information for preventing or relieving these effects. Also find information on maintaining proper nutrition during cancer treatment.

227

Effective 4-H Meetings  

E-print Network

As a 4-H volunteer, you will have different functions. An especially important task is to prepare interesting and effective meetings where youth can obtain the greatest educational benefit while having fun. This publication outlines effective...

Howard, Jeff W.

2005-05-10

228

Stormwater BMP Effectiveness Toolkit  

EPA Science Inventory

US EPA has identified the effectiveness of Stormwater Best Management Practices (BMPs) as a priority research need. Effective protection of biotic integrity requires that processes maintaining the diversity of physical habitats be protected. Methods are needed to evaluate the e...

229

Prednisone [Possible Side Effects  

MedlinePLUS

Prednisone is a corticosteroid. In contrast to anabolic steroids (used by “bodybuilders”), corticosteroids are used in inflammatory ... Side Effects Many of the side–effects of steroids are predictable. All are related to: 1) the ...

230

Side Effects (Management)  

MedlinePLUS

... cancer care is relieving side effects, called symptom management, palliative care, or supportive care. It is important ... treat them. To learn about the symptoms and management of the long-term side effects of cancer ...

231

Scale effects in transmissivity  

Microsoft Academic Search

Heterogeneity accounts for several paradoxes in groundwater flow and solute transport. One of the most striking observations is the emergence of scale effects in transmissivity, that is, the increase in effective transmissivity (or hydraulic conductivity, for that matter) with increasing scale of observation. Traditional stochastic approaches, where transmissivity is treated as a multilog-normal random function, lead to a large-scale effective

Xavier Sánchez-Vila; Jesús Carrera; Jorge P. Girardi

1996-01-01

232

Psychological effects of drugs  

Microsoft Academic Search

Reviews reports (1912-1913) on the effects of drugs. The influence of alcohol, tea, and coffee on the speed and accuracy of work in type-writing reveals that alcohol decreases speed and increases errors. Tea and caffeine increase the amount of work. In regard to the effects of alcohol on mental and muscular activity, it has a brief stimulating effect which is

1914-01-01

233

Effects of Nuclear Weapons.  

ERIC Educational Resources Information Center

Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

Sartori, Leo

1983-01-01

234

Effective scientific communication  

E-print Network

Effective scientific communication in biomedicine is the basic mechanism of existence and progress of science. For effective written scientific communication it is not enough only to publish report of obtained scientific results. Scientific article must be written in a way to be easily noticed and understand by the reader. Moreover, effective scientific communication includes the response of readers (feedback) to published information. In this article several facts, important for effective scientific communication, are emphasized: publication is an integral part of scientific meted of knowledge, the reasons why the results of scientific research must be published and the way to write and publish to be included in effective scientific communication.

Jovan Saviæ

235

Strongly nonlinear thermovoltage and heat dissipation in interacting quantum dots  

NASA Astrophysics Data System (ADS)

We investigate the nonlinear regime of charge and energy transport through Coulomb-blockaded quantum dots. We discuss crossed effects that arise when electrons move in response to thermal gradients (Seebeck effect) or energy flows in reaction to voltage differences (Peltier effect). We find that the differential thermoelectric conductance shows a characteristic Coulomb butterfly structure due to charging effects. Importantly, we show that experimentally observed thermovoltage zeros are caused by the activation of Coulomb resonances at large thermal shifts. Furthermore, the power dissipation asymmetry between the two attached electrodes can be manipulated with the applied voltage, which has implications for the efficient design of nanoscale coolers.

Sierra, Miguel A.; Sánchez, David

2014-09-01

236

Allee effects in ants.  

PubMed

1. Allee effects occur when the aggregation of individuals result in mutually beneficial intraspecific interactions whereby individual fitness, or per capita growth rate, increases with the number of individuals. Allee effects are common in social species due to their cooperative behaviours, such as breeding, feeding or defence. Allee effects have important implications for many aspects of basic and applied ecology. Over the past decades, the study of Allee effects has influenced population dynamics, community ecology, endangered species management and invasion biology. 2. Despite the fact that cooperation is the basis of their social structure, Allee effects have received little attention among eusocial insects. Extreme cooperation is common, and reproductive specialization of individuals occurs due to division of labour. These life-history traits suggest that the potential contribution of each caste to reproduction and survival may be differential and nonadditive. 3. We studied Allee effects in the invasive Argentine ant (Linepithema humile). In this species, many queens and workers are present in colonies, which allowed us to explore the differential effects of castes on the presence of Allee effects. In the laboratory, we measured brood production and individual survival in experimental colonies that differed in the initial numbers of queens and workers.4. Our results highlight the differential effect of queens and workers on survival and productivity. We found three positive density-dependent relationships indicative of component Allee effects at the colony level: both workers and queens had a positive effect on the productivity of the other caste, and queens had a positive effect on worker survivorship. 5. Our experimental results suggest a potential positive feedback between worker and queen abundance, which may have contributed to the evolution of large colony sizes. Our study provides the first evidence of Allee effects in eusocial insects and highlights the need to consider castes separately in population dynamics. Division of labour and differential reproductive rates are factors that should be integrated into the study of Allee effects. PMID:23672650

Luque, Gloria M; Giraud, Tatiana; Courchamp, Franck

2013-09-01

237

Giant thermoelectric effect in graphene-based topological insulators with heavy adatoms and nanopores.  

PubMed

Designing thermoelectric materials with high figure of merit ZT = S(2)GT/Ktot requires fulfilling three often irreconcilable conditions, that is, the high electrical conductance G, small thermal conductance Ktot, and high Seebeck coefficient S. Nanostructuring is one of the promising ways to achieve this goal as it can substantially suppress lattice contribution to Ktot. However, it may also unfavorably influence the electronic transport in an uncontrollable way. Here, we theoretically demonstrate that this issue can be ideally solved by fabricating graphene nanoribbons with heavy adatoms and nanopores. The adatoms locally enhance spin-orbit coupling in graphene thereby converting it into a two-dimensional topological insulator with a band gap in the bulk and robust helical edge states, which carry electrical current and generate a highly optimized power factor S(2)G per helical conducting channel due to narrow boxcar-function-shaped electronic transmission (surpassing even the Mahan-Sofo limit obtained for delta-function-shaped electronic transmission). Concurrently, the array of nanopores impedes the lattice thermal conduction through the bulk. Using quantum transport simulations coupled with first-principles electronic and phononic band structure calculations, the thermoelectric figure of merit is found to reach its maximum ZT ? 3 at low temperatures T ? 40 K. This paves a way to design high-ZT materials by exploiting the nontrivial topology of electronic states through nanostructuring. PMID:24932511

Chang, Po-Hao; Bahramy, Mohammad Saeed; Nagaosa, Naoto; Nikoli?, Branislav K

2014-07-01

238

Magnetothermoelectric effects in Fe1+dTe1-xSex  

NASA Astrophysics Data System (ADS)

We report resistivity as well as the Hall, Seebeck and Nernst coefficients data for Fe1+dTe1-xSex single crystals with x = 0, 0.38, and 0.40. In the parent compound Fe1.04Te we observe at TN = 61 K a sudden change of all quantities studied, which can be described to the Fermi surface reconstruction due to onset of the antiferromagnetic order. Two very closely doped samples: Fe1.01Te0.62Se0.38 (Se38) and Fe1.01Te0.60Se0.40 (Se40) are superconductors with Tc = 13.4 K and 13.9 K, respectively. There are no evident magnetic transitions in either Se38 or Se40. Properties of these two single crystals are almost identical at high temperatures, but start to diverge below T ? 80 K. Perhaps we see the onset of scattering that might be a related to changes in short range magnetic correlations caused by selenium doping.

Matusiak, Marcin; Pomjakushina, Ekaterina; Conder, Kazimierz

2012-12-01

239

The butterfly effect of the "butterfly effect".  

PubMed

The "Butterfly Effect" metaphor states with variance that the flap of a butterfly's wings in Brazil can cause a tornado in Texas. This metaphor has become part of the common vernacular of Western culture. In this paper I discuss the origins of the metaphor, examine its current usage within popular culture, and present an argument as to why it is popular. I propose that the metaphor is a type of semantic attractor, a narrative device with invariant meaning but audience-specific contextualization. Finally I address whether the Butterfly Effect metaphor is a good example of itself. PMID:19527619

Dooley, Kevin J

2009-07-01

240

Blowing Ratio Effects on Film Cooling Effectiveness  

E-print Network

The research focuses on testing the film cooling effectiveness on a gas turbine blade suction side surface. The test is performed on a five bladed cascade with a blow down facility. Four different blowing ratios are used in this study, which are 0...

Liu, Kuo-Chun

2010-01-14

241

Effective Strategies Brief  

NSDL National Science Digital Library

In this research brief the authors detail effective teaching strategies for teaching students with difficulties in math. The brief summarizes the work of over fifty research studies and details the practices that were seen as consistently effective across many of them. The brief details six instructional strategies and presents data describing the effectiveness of each on special education students and low-achieving students. The brief can be viewed on the webpage or downloaded as a PDF.

Gersten, Russell; Clarke, Benjamin S.

2007-01-01

242

Space applications of shape memory alloys  

E-print Network

junction to become hot and the other one cold [26]. Jean Charles Athanase Peltier (1785-1845) was a French watchmaker who became a scientist and discovered this reversible effect in 1834. The opposite effect is called the Seebeck effect after the German... to these free electrons. When the two materials are put in contact with one junction kept cold, and the other one kept hot, the free electrons will flow from the more conductive to the less conductive material trying to reach a new equilibrium, and therefore...

Godard, Olivier Jean

2012-06-07

243

Volcanic effects on climate  

NASA Technical Reports Server (NTRS)

Volcanic eruptions which inject large amounts of sulfur-rich gas into the stratosphere produce dust veils which last years and cool the earth's surface. At the same time, these dust veils absorb enough solar radiation to warm the stratosphere. Since these temperature changes at the earth's surface and in the stratosphere are both in the opposite direction of hypothesized effects from greenhouse gases, they act to delay and mask the detection of greenhouse effects on the climate system. Tantalizing recent research results have suggested regional effects of volcanic eruptions, including effects on El Nino/Southern Oscillation (ENSO). In addition, a large portion of the global climate change of the past 100 years may be due to the effects of volcanoes, but a definite answer is not yet clear. While effects of several years were demonstrated with both data studies and numerical models, long-term effects, while found in climate model calculations, await confirmation with more realistic models. Extremely large explosive prehistoric eruptions may have produced severe weather and climate effects, sometimes called a 'volcanic winter'. Complete understanding of the above effects of volcanoes is hampered by inadequacies of data sets on volcanic dust veils and on climate change. Space observations can play an increasingly important role in an observing program in the future. The effects of volcanoes are not adequately separated from ENSO events, and climate modeling of the effects of volcanoes is in its infancy. Specific suggestions are made for future work to improve the knowledge of this important component of the climate system.

Robock, Alan

1991-01-01

244

Effects of Drug Abuse  

MedlinePLUS

Listen to this page Effects of Drug Abuse Drug abuse hurts the people who take drugs AND the people around them, including families , kids , and ... HIV/AIDS Click here to learn more about effects of specific drugs . VIDEO: Why Are Drugs So ...

245

Earthquake Effects and Experiences  

NSDL National Science Digital Library

This portion of the United States Geological Survey's (USGS) frequently-asked-questions feature on earthquakes addresses what individuals might actually experience during an earthquake. Topics include earthquake motion (rolling or shaking), earthquake effects (ground shaking, surface faulting, ground failure, etc.), earthquake magnitude, what an earthquake feels like, and others. There are also links to additional resources on earthquake effects and experiences.

2010-11-23

246

Effects on aquatic ecosystems  

Microsoft Academic Search

Regarding the effects of UV-B radiation on aquatic ecosystems, recent scientific and public interest has focused on marine primary producers and on the aquatic web, which has resulted in a multitude of studies indicating mostly detrimental effects of UV-B radiation on aquatic organisms. The interest has expanded to include ecologically significant groups and major biomass producers using mesocosm studies, emphasizing

D.-P. Häder; H. D. Kumar; R. C. Smith; R. C. Worrest

1998-01-01

247

The Kaye effect  

Microsoft Academic Search

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, The Kaye effect, as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid is poured onto a surface.

J. M. Binder; A. J. Landig

2009-01-01

248

Generalized gravitomagnetic clock effect  

E-print Network

In General Relativity, the rotation of a gravitating body like the Earth influences the motion of orbiting test particles or satellites in a non-Newtonian way. This causes, e.g., a precession of the orbital plane known as the Lense-Thirring effect and a precession of the spin of a gyroscope known as the Schiff effect. Here, we discuss a third effect first introduced by Cohen and Mashhoon called the gravitomagnetic clock effect. It describes the difference in proper time of counterrevolving clocks after a revolution of $2\\pi$. For two clocks on counterrotating equatorial circular orbits around the Earth, the effect is about $10^{-7}$ seconds per revolution, which is quite large. We introduce a general relativistic definition of the gravitomagnetic clock effect which is valid for arbitrary pairs of orbits. This includes rotations in the same direction and different initial conditions, which are crucial if the effect can be detected with existing satellites or with payloads on nondedicated missions. We also derive the post-Newtonian expansion of the general relativistic expression and calculate the effect for the example of a satellite of a Global Navigation Satellite System compared to a geostationary satellite.

Eva Hackmann; Claus Lämmerzahl

2014-06-24

249

Generalized gravitomagnetic clock effect  

NASA Astrophysics Data System (ADS)

In general relativity, the rotation of a gravitating body like the Earth influences the motion of orbiting test particles or satellites in a non-Newtonian way. This causes, e.g., a precession of the orbital plane known as the Lense-Thirring effect and a precession of the spin of a gyroscope known as the Schiff effect. Here, we discuss a third effect first introduced by Cohen and Mashhoon called the gravitomagnetic clock effect. It describes the difference in proper time of counterrevolving clocks after a revolution of 2?. For two clocks on counterrotating equatorial circular orbits around the Earth, the effect is about 10-7 s per revolution, which is quite large. We introduce a general relativistic definition of the gravitomagnetic clock effect which is valid for arbitrary pairs of orbits. This includes rotations in the same direction and different initial conditions, which are crucial if the effect can be detected with existing satellites or with payloads on nondedicated missions. We also derive the post-Newtonian expansion of the general relativistic expression and calculate the effect for the example of a satellite of a global navigation satellite system compared to a geostationary satellite.

Hackmann, Eva; Lämmerzahl, Claus

2014-08-01

250

Effective Learning in Classrooms  

ERIC Educational Resources Information Center

This book addresses an important and seldom addressed issue: learning. Not teaching, not performance, not "work": this book really is about learning, what makes learning effective and how it may be promoted in classrooms. The authors take the context of the classroom seriously, not only because of its effects on teachers and pupils, but because…

Watkins, Chris; Carnell, Eileen; Lodge, Caroline M.

2007-01-01

251

Aharonov-Bohm Effect  

NSDL National Science Digital Library

This web page illustrates the effect of a magnetic flux on the interference of a quantum double-slit experiment. The time-dependent scattering patterns are shown with and without a magnetic field. In addition, the effects of changing the topology of the system are discussed and displayed.

Michielsen, Kristel; De Raedt, Hans

2004-03-10

252

The polarized EMC effect  

SciTech Connect

We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

Bentz, W. [Department of Physics, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Cloet, I. C. [Special Research Centre for the Subatomic Structure of Matter, University of Adelaide, SA 5005 (Australia); Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Thomas, A. W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2007-02-27

253

The polarized EMC effect  

SciTech Connect

We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

W. Bentz; I. C. Cloet; A. W. Thomas

2007-02-01

254

Photovoltaic effect applications  

Microsoft Academic Search

The photovoltaic effect is examined theoretically with attention given to efficiency as a function of the energy band gap. The properties of a number of solar-cell materials (silicon and gallium arsenide) are discussed, considering energy losses, the effects of doping on mobility, lifetime, and diffusion length, efficiency as a function of junction depth, and the characteristics of surface coatings. Different

F. P. Califano

1976-01-01

255

CCTV effectiveness study  

Microsoft Academic Search

The field of CCTV surveillance is topical and widely used in many different applications. The fundamental part of the CCTV system is a reliable image evaluation by a human observer, whose effectiveness is influenced by many variables. Optimization of the effectiveness is a multidimensional problem related to both technical and human characteristics. In many applied systems, the overall performance is

G. van Voorthuijsen; H. van Hoof; M. Klima; K. Roubik; M. Bernas; P. Pata

2005-01-01

256

JPL Radiation Effects Facilities  

NASA Technical Reports Server (NTRS)

Radiation Effects Group investigates the effects of space radiation on present and future microelectronic and optoelectronic technologies, evaluate the risk of using them in specific space missions, and recommend component and design techniques for JPL and NASA programs to reduce reliability risk from space radiation.

Thorbourn, Dennis

2013-01-01

257

Effects of Mobile Communication  

Microsoft Academic Search

Before reviewing some of the key consequences of mobile communication technology, a brief discussion of how they fit within the media effects paradigm is in order. At the risk of oversimplification, we understand the media effects paradigm as a framework for understanding how mass media content influences attitudes and behavior of audience members. To be fair, it is important to

Scott W. Campbell

258

Earthquake Effects and Experiences  

NSDL National Science Digital Library

This portion of the United States Geological Survey's (USGS) frequently-asked-questions feature on earthquakes addresses what individuals might actually experience during an earthquake. Topics include earthquake motion (rolling or shaking), earthquake effects (ground shaking, surface faulting, ground failure, etc.), earthquake magnitude, what an earthquake feels like, and others. There are also links to additional resources on earthquake effects and experiences.

259

Interdependence and Group Effectiveness.  

ERIC Educational Resources Information Center

Investigated the differential effects of task design and reward system design on group functioning in a large U.S. corporation; the effectiveness of "hybrid" groups (having tasks and rewards with both individual and group elements); and how individuals' autonomy preferences moderate their responses to interdependence. Groups performed best when…

Wageman, Ruth

1995-01-01

260

Adverse effects of Benzodiazepines  

Microsoft Academic Search

The growing realisation that the benzodiazepines have potential for causing serious harm has caused concern due to their wide and common use. This paper is a review of the adverse effects of benzodiazepines, and concentrates on four areas of particular concern; drug dependence with the consequent withdrawal symptoms; psychological effects while on the drugs; use by the elderly; and tolerance

C. Gudex

1991-01-01

261

The Kaye Effect  

ERIC Educational Resources Information Center

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, "The Kaye effect", as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid…

Binder, J. M.; Landig, A. J.

2009-01-01

262

effectively tax treaty?  

E-print Network

Is income effectively connected to US trade/ business? Is this exempt under the tax treaty? Does- employee comp? Is income "effectively connected"? Is payment subject to a lower tax rate? Is payment for rent or royalty? Individual completes IRS form 1001. Payment will not be taxed. (Code "N") Taxes

Krovi, Venkat

263

Comparative Effectiveness Research  

Cancer.gov

Comparative Effectiveness Research (CER) is the conduct and synthesis of systematic research comparing different interventions and strategies to prevent, diagnose, treat and monitor health conditions. The purpose of this research is to inform patients, providers, and decision-makers about which interventions are most effective for which patients under specific circumstances.

264

Side effects of antibiotics  

Microsoft Academic Search

A review of the side effects of antibiotics in human patients is presented. At least three classes of untoward reactions may be distinguished: development of drug hypersensitivity, toxicological hazards, and microbial effects such as emergence of drug resistance.The intrinsic toxicities of the oldest discoveries, penicillin and sulphonamides, have turned out te be very low for most animals as well as

A. Manten

1981-01-01

265

Cardiovascular Effects of Felypressin  

PubMed Central

Cardiovascular effects of felypressin (FEL) were studied in Wistar rats. Heart rate and mean arterial pressure measurements were taken in awake rats treated with vasopressin (AVP), FEL, or epinephrine (EPI). Each group received either an intravenous (IV) or an intracerebroventricular V1 receptor antagonist, saline, area postrema removal, or sham surgery. Analysis of variance and Student-Newman-Keuls (P < .05) were applied. Felypressin and AVP induced a pressor effect, and bradycardia was inhibited by IV V1 antagonist. Intracerebroventricular V1 antagonist and area postrema removal enhanced their pressor effects. Epinephrine induced a higher pressor effect and a similar bradycardia that was not affected by the treatments. It was concluded that FEL depends on V1 receptors to induce pressor and bradycardic effects, and that it produces a high relationship between bradycardia and mean arterial pressure variation depending on area postrema and central V1 receptors. These effects are potentially less harmful to the cardiovascular system than the effects of EPI. PMID:17177590

Cecanho, Rodrigo; De Luca, Laurival Antonio; Ranali, José

2006-01-01

266

CAUSE & EFFECT What Is It?  

E-print Network

CAUSE & EFFECT What Is It? Cause and effect analysis answers the questions: "Why did this happen questions: Is there really a cause and effect relationship between these two events? If there really is a cause and effect relationship, what is the exact connection between the cause(s) and the effect(s)? What

Boonstra, Rudy

267

Effective Field Theories  

NASA Astrophysics Data System (ADS)

Effective field theories encode the predictions of a quantum field theory at low energy. The effective theory has a fairly low ultraviolet cutoff. As a result, loop corrections are small, at least if the effective action contains a term which is quadratic in the fields, and physical predictions can be read straight from the effective Lagrangian. Methods will be discussed how to compute an effective low energy action from a given fundamental action, either analytically or numerically, or by a combination of both methods. Basically, the idea is to integrate out the high frequency components of fields. This requires the choice of a "blockspin", i.e. the specification of a low frequency field as a function of the fundamental fields. These blockspins will be the fields of the effective field theory. The blockspin needs not be a field of the same type as one of the fundamental fields, and it may be composite. Special features of blockspins in nonabelian gauge theories will be discussed in some detail. In analytical work and in multigrid updating schemes one needs interpolation kernels A from coarse to fine grid in addition to the averaging kernels C which determines the blockspin. A neural net strategy for finding optimal kernels is presented. Numerical methods are applicable to obtain actions of effective theories on lattices of finite volume. The special case of a "lattice" with a single site (the constraint effective potential) is of particular interest. In a Higgs model, the effective action reduces in this case to the free energy, considered as a function of a gauge covariant magnetization. Its shape determines the phase structure of the theory. Its loop expansion with and without gauge fields can be used to determine finite size corrections to numerical data.

Mack, G.; Kalkreuter, T.; Palma, G.; Speh, M.

268

Bustling argon: biological effect  

PubMed Central

Argon is a noble gas in group 18 of the periodic table. Certificated to exist in air atmosphere merely one century ago, discovery of argon shows interesting stories of researching and exploring. It was assumed to have no chemical activity. However, argon indeed present its biological effect on mammals. Narcotic effect of argon in diving operation and neur-protective function of argon in cerebral injury demonstrate that argon has crucial effect and be concentrated on is necessary. Furthermore, consider to be harmless to human, argon clinical application in therapy would be another option. PMID:24088583

2013-01-01

269

[Cholinergic effects of nootropics].  

PubMed

With respect to the enhancing effect of nootropics on learning and memory, the influence of some of these drugs on the high affinity choline uptake has been investigated. Meclofenoxate competes with choline uptake in vitro because of its similar side chain; other nootropics are without in vitro effects. A single dose of pramiracetam enhances the choline uptake in cortex and hippocampus. Application of meclofenoxate decreases the uptake of choline. Other nootropics lack acute effects. Possible increases of uptake after repeated dosage disappear within 24 h. PMID:3149192

Funk, K F; Schmidt, J

1988-01-01

270

Bustling argon: biological effect.  

PubMed

Argon is a noble gas in group 18 of the periodic table. Certificated to exist in air atmosphere merely one century ago, discovery of argon shows interesting stories of researching and exploring. It was assumed to have no chemical activity. However, argon indeed present its biological effect on mammals. Narcotic effect of argon in diving operation and neur-protective function of argon in cerebral injury demonstrate that argon has crucial effect and be concentrated on is necessary. Furthermore, consider to be harmless to human, argon clinical application in therapy would be another option. PMID:24088583

Ye, Zhouheng; Zhang, Rongjia; Sun, Xuejun

2013-01-01

271

Explore Learning: Doppler Effect  

NSDL National Science Digital Library

This site contains a Shockwave interactive animation used to teach students about the wave motion specific to doppler effect. Users can change frequency, wave speed, as well as source and detector speeds.

2004-12-15

272

Matthew: Effect or Fable?  

E-print Network

In a market context, a status effect occurs when actors are accorded differential recognition for their efforts depending on their location in a status ordering, holding constant the quality of these efforts. In practice, ...

Azoulay, Pierre

273

Strategies for Effective Outsourcing.  

ERIC Educational Resources Information Center

Emphasizes strategies that can be employed for effective outsourcing in higher education settings. Several models of outsourcing are identified and described, and examples of institutions using each model are provided. (GCP)

Moneta, Larry; Dillon, William L.

2001-01-01

274

Conducting Effective Performance Evaluations  

E-print Network

Conducting Effective Performance Evaluations February 2013 #12;Performance Management v probationary employees ­ conduct the discussion immediately upon conclusion of the probationary period is required before considering a supervisor's request to award Flexible Pay Options available through the MUS

Lawrence, Rick L.

275

[Profibrotic effects of aldosterone].  

PubMed

Animal studies have shown that during high sodium intake aldosterone induces cardiac fibrosis and renal nephrosclerosis through activation of mineralocorticoid receptors. In the human heart mineralocorticoid receptors and activity of the enzyme 11beta-hydroxysteroid-dehydrogenase type 2, which is required for the activation of mineralocorticoid receptors by aldosterone, are both present. In clinical medicine the profibrotic effect of aldosterone has been related to diastolic dysfunction, arrhythmia and progression of cardiac and renal failure. The addition of an aldosterone receptor antagonist to optimal treatment in patients with heart failure causes a decrease in serum markers of collagen turnover and a decline in cardiac morbidity and mortality. These findings are a strong indication of a profibrotic effect of aldosterone in cardiac failure. Studies concerning the profibrotic effect of aldosterone in patients with primary hyperaldosteronism are contradictory and at the moment no data are available about a potential antifibrotic effect of aldosterone receptor antagonists in patients with impaired renal function. PMID:15366722

Van Den Meiracker, A H; Huizenga, A T M; Boomsma, F

2004-07-31

276

Ototoxic Medications (Medication Effects)  

MedlinePLUS

... hearing and balance should be recorded by an audiologist. The baseline record should include an audiologic hearing ... be stopped or changed, the patient and the audiologist can take steps to manage the effects of ...

277

[Economical effect of vaccine].  

PubMed

In Japan, some vaccines are provided partially or only at citizens' own expense, while France and Germany publicly cover immunization on the basis of findings in economical effect on VPD (vaccine preventable disease). Such study recently conducted in Japan by the government was reported. According to cost comparative analysis, pneumococcal conjugate vaccine (PCV) for both children and adults, mumps, and varicella were found to have certain economical effect, while cervical cancer, hepatitis B, and Hib virus were not. Cost effectiveness analysis found PCV for adults, pertussis, mumps, and cervical cancer to have favorable effect, while not for Hib and PCV for children. These results offer some perspective, but cautious interpretation may be necessary since premises differ among analyses. PMID:21922773

Kawabuchi, Koichi

2011-09-01

278

Training Services Organizational Effectiveness  

E-print Network

ULearn Training Services Organizational Effectiveness 612-626-1373 trngsvcs@umn.edu www/material is available in alternative formats upon request. Please contact University of Minnesota Training Services, 260 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Search for Training

Minnesota, University of

279

Radiation effects in space  

SciTech Connect

The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

Fry, R.J.M.

1986-01-01

280

Chesapeake Bay Impact Effects  

NSDL National Science Digital Library

This PowerPoint show depicts the effects (blast, heat, etc.) of the Chesapeake Bay impact. To emphasize the human consequences of asteroid and comet impacts, the slides show what would happen to East Coast communities if an identical object hit the same place today. (The impact actually happened roughly 35 million years ago.) Impact effects were estimated with the Earth Impact Effects Program (www.lpl.arizona.edu/impacteffects/). Effects shown on these slides are at best very approximate, and, consequently, these slides should only be used to stimulate discussions about impact hazards. Satellite images were obtained through the NASA Earth Observing System Higher Education Alliance (GeoBrain) which provided funding for this work. Graphics were created with the Environmental Systems Research Institute (ESRI) family of geographic information system (GIS) products.

Abolins, Mark; Univiversity, Middle T.

281

[Adverse effects of atazanavir].  

PubMed

Atazanavir is a drug that inhibits HIV protease. It has many of the characteristics of other protease inhibitors and also some advantages over these, such as the single dose of once per day, low capsule load, less gastrointestinal problems and a very friendly metabolic profile, including carbohydrate metabolism. Secondary high plasma bilirubin and jaundice are its main adverse effect which only on rare occasions requires stopping the drug. Other adverse effects, such as nephrolithiasis or ECG changes are extremely rare. PMID:20116616

Palacios, R; González, M; Ruiz, J; Santos, Jesús

2008-12-01

282

Doppler Effect JS Model  

NSDL National Science Digital Library

The Doppler Effect JS Model shows five different animations with different combinations of moving/stationary sources/detectors. The final animation shows what happens when a source exceeds the speed of sound. The Doppler Effect JS Model was developed using the Easy Java Simulations (EJS) version 5. It is distributed as a ready-to-run html page and requires only a browser with JavaScript support. It is also distributed as an ePub.

Kennedy, Matt; Dixon, Rachel

2014-07-02

283

Interpersonal effectiveness training  

E-print Network

, and behavior modification. Conjoint family therapy, the first to treat husband and wife together at the same time, strives to develop techniques for pro- moting expression of one's real feelings and attitudes, thereby reduc- ing barriers to free, genuine...-exploration and that this training is more effective than insight therapy. Steele (1968) designed a workshop for clients with identified needs which demonstrated that stating objectives in behaviorally clear language is more effective than open-ended, non- structured...

DeOtte, Dona Lou Lewis

2012-06-07

284

Modulational effects in accelerators  

SciTech Connect

We discuss effects of field modulations in accelerators, specifically those that can be used for operational beam diagnostics and beam halo control. In transverse beam dynamics, combined effects of nonlinear resonances and tune modulations influence diffusion rates with applied tune modulation has been demonstrated. In the longitudinal domain, applied RF phase and voltage modulations provide mechanisms for parasitic halo transport, useful in slow crystal extraction. Experimental experiences with transverse tune and RF modulations are also discussed.

Satogata, T.

1997-12-01

285

The Doppler Effect  

NSDL National Science Digital Library

This Flash animation provides a simulation of the Doppler effect. The user can change the speed of the wave source and can move a microphone to detect the wave frequency at different points relative to the moving source. The resulting wave pattern can be both observed and heard. Instructional notes outlining the details of the Doppler effect are provided. This material is part of a web site for a second semester physics course for majors covering gravity, fluids, waves, and thermodynamics.

Fowler, Michael; Welch, Heather

2008-07-31

286

Effects of periodic discharges  

NASA Technical Reports Server (NTRS)

Periodic capacity checks are assessed as well as the effects of periodic discharges on the cycle life and the performance of cells during the cycle life. Topics discussed include the effect of the amount of electrolyte on cell capacity at 35 C; battery design for spacecraft; electrolyte starvation theory; battery separator degradation; negative electrode stability; voltage regulation; operating temperatures; and integration of reconditioning systems using microprocessors.

Ford, F. E.

1977-01-01

287

Vacuum Boundary Effects  

E-print Network

The effect of boundary conditions on the vacuum structure of quantum field theories is analysed from a quantum information viewpoint. In particular, we analyse the role of boundary conditions on boundary entropy and entanglement entropy. The analysis of boundary effects on massless free field theories points out the relevance of boundary conditions as a new rich source of information about the vacuum structure. In all cases the entropy does not increase along the flow from the ultraviolet to the infrared.

M. Asorey; J. M. Munoz-Castaneda

2008-03-18

288

Low-Temperature Thermoelectric Properties of PtSb2-x Te x for Cryogenic Peltier Cooling Applications  

NASA Astrophysics Data System (ADS)

PtSb2 is a potential material for cryogenic Peltier cooling applications because of its semimetal character with a high Seebeck coefficient and low electrical resistivity. To investigate the effects of n-type doping we studied PtSb2-x Te x with x between 0 and 0.04. A clear doping effect was observed, and the power factor was maximized for samples with x = 0.005, 0.02, and 0.04. If thermal conductivity reduction techniques can be used, this material may be a promising candidate for cryogenic Peltier cooling applications.

Waldrop, Spencer; Morelli, Donald

2014-10-01

289

Thermally driven spin and charge currents in thin NiFe2O4/Pt films  

NASA Astrophysics Data System (ADS)

We present results on the longitudinal spin Seebeck effect (LSSE) shown by semiconducting ferrimagnetic NiFe2O4/Pt films from room temperature down to 50 K base temperature. The temperature dependence of the conductivity has been studied in parallel to obtain information about the origin of the electric potentials detected at the Pt coverage of the ferrimagnet in order to distinguish the LSSE from the anomalous Nernst effect. Furthermore, the dependence of the LSSE on temperature gradients as well as the influence of an external magnetic field direction is investigated.

Meier, D.; Kuschel, T.; Shen, L.; Gupta, A.; Kikkawa, T.; Uchida, K.; Saitoh, E.; Schmalhorst, J.-M.; Reiss, G.

2013-02-01

290

Thermomagnetic phenomena in the mixed state of high temperature superconductors  

NASA Technical Reports Server (NTRS)

Galvano- and thermomagnetic-phenomena in high temperature superconductors, based on kinetic coefficients, are discussed, along with a connection between the electric field and the heat flow in superconductor mixed state. The relationship that determines the transport coefficients of high temperature superconductors in the mixed state based on Seebeck and Nernst effects is developed. It is shown that this relationship is true for a whole transition region of the resistive mixed state of a superconductor. Peltier, Ettingshausen and Righi-Leduc effects associated with heat conductivity as related to high temperature superconductors are also addressed.

Meilikhov, E. Z.

1995-01-01

291

Effects and side effects of inspections and accountability in education  

Microsoft Academic Search

This paper presents an overview of studies into effects and side effects of control mechanisms in education. We focus on effects and side effects of inspection visits and public performance indicators. A first conclusion is that the studies do not provide us with a clear answer to the question of whether inspection visits have positive causal effects on quality of

Wolff de I; F. Janssens

2005-01-01

292

Causes of Effects and Effects of Causes Judea Pearl  

E-print Network

Causes of Effects and Effects of Causes Judea Pearl University of California, Los Angeles Computer "Effect of Causes" (EoC) and "Causes of Effect" (CoE). My aim in this comment is to share with readers a progress report on what has been accomplished on the question of "causes of effects," CoE, how far we have

California at Los Angeles, University of

293

[Clinical effect and side effect of troglitazone].  

PubMed

Troglitazone, a PPAR-gamma agonist, is a new drug for type 2 diabetes. The drug decreases blood glucose via enhancing insulin action. Recently Sankyo pharmaceutical company is warning severe hepatotoxicity by troglitazone. It recommends to examine liver function every month in diabetic patients treated with the drug in order early to find drug-induced hepatitis. In Japan 153 diabetic patients treated with the drug developed severe hepatitis and 8 of them died of drug-side effects. Quinone metabolite of troglitazone predominantly in the liver to a sulfate conjugate and activation of PPAR gamma and PXR(pregnane X receptor) by troglitazone are supposed to be factors of hepatotoxic mechanism. PMID:10707561

Toyota, T; Ueno, Y

2000-02-01

294

Effective Transport Properties  

NASA Astrophysics Data System (ADS)

In this chapter we study a particular case of multiphase systems, namely two-phase materials in which one of the phases is randomly dispersed in the other, so that the composite can be viewed on a macroscale as an effective continuum, with well defined properties. In general, the theoretical determination of the parameter for an effective medium requires, as a rule, the solution of a corresponding transport problem at the microscale, which takes into account the morphology of the system and its evolution. As the mathematical problem is well-posed on a microscale, this can be accomplished using, for example, the multiple scale approach shown in Chap. 11 ; however, the task requires massive computations and is therefore difficult to implement from the practical standpoint. Here, instead, we focus on a deterministic approach to the problem, where the geometry and spatial configuration of the particles comprising the included phase are given and the solution to the microscale problem is therefore sought analytically. As examples, we study the effective thermal conductivity of solid reinforced materials (Sect. 10.1), the effective viscosity of non-colloidal suspensions (Sect. 10.2), the effective permeability of porous materials (10.3) and the effective self- and gradient diffusivities of colloidal suspensions (Sect. 10.4). Then, in Sect. 10.5, an alternative dynamic definition of the transport coefficients is considered, which can also serve as a basis to determine the effective properties of complex systems.

Mauri, Roberto

295

A "voice inversion effect?".  

PubMed

Voice is the carrier of speech but is also an "auditory face" rich in information on the speaker's identity and affective state. Three experiments explored the possibility of a "voice inversion effect," by analogy to the classical "face inversion effect," which could support the hypothesis of a voice-specific module. Experiment 1 consisted of a gender identification task on two syllables pronounced by 90 speakers (boys, girls, men, and women). Experiment 2 consisted of a speaker discrimination task on pairs of syllables (8 men and 8 women). Experiment 3 consisted of an instrument discrimination task on pairs of melodies (8 string and 8 wind instruments). In all three experiments, stimuli were presented in 4 conditions: (1) no inversion; (2) temporal inversion (e.g., backwards speech); (3) frequency inversion centered around 4000 Hz; and (4) around 2500 Hz. Results indicated a significant decrease in performance caused by sound inversion, with a much stronger effect for frequency than for temporal inversion. Interestingly, although frequency inversion markedly affected timbre for both voices and instruments, subjects' performance was still above chance. However, performance at instrument discrimination was much higher than for voices, preventing comparison of inversion effects for voices vs. non-vocal stimuli. Additional experiments will be necessary to conclude on the existence of a possible "voice inversion effect." PMID:15177788

Bédard, Catherine; Belin, Pascal

2004-07-01

296

Effective Documentation Tools  

NASA Technical Reports Server (NTRS)

Quality assurance programs provide a very effective means to monitor and evaluate medical care. Quality assurance involves: (1) Identify a problem; (2) Determine the source and nature of the problem; (3) Develop policies and methods to effect improvement; (4) Implement those polices; (5) Monitor the methods applied; and (6) Evaluate their effectiveness. Because this definition of quality assurance so closely resembles the Nursing Process, the health unit staff was able to use their knowledge of the nursing process to develop many forms which improve the quality of patient care. These forms include the NASA DFRC Service Report, the occupational injury form (Incident Report), the patient survey (Pre-hospital Evaluation/Care Report), the Laboratory Log Sheet, the 911 Run Sheet, and the Patient Assessment Stamp. Examples and steps which are followed to generate these reports are described.

Sleboda, Claire

1997-01-01

297

Effective Nutritional Supplement Combinations  

NASA Astrophysics Data System (ADS)

Few supplement combinations that are marketed to athletes are supported by scientific evidence of their effectiveness. Quite often, under the rigor of scientific investigation, the patented combination fails to provide any greater benefit than a group given the active (generic) ingredient. The focus of this chapter is supplement combinations and dosing strategies that are effective at promoting an acute physiological response that may improve/enhance exercise performance or influence chronic adaptations desired from training. In recent years, there has been a particular focus on two nutritional ergogenic aids—creatine monohydrate and protein/amino acids—in combination with specific nutrients in an effort to augment or add to their already established independent ergogenic effects. These combinations and others are discussed in this chapter.

Cooke, Matt; Cribb, Paul J.

298

Aviation noise effects  

NASA Astrophysics Data System (ADS)

This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

Newman, J. S.; Beattie, K. R.

1985-03-01

299

Habituation of reinforcer effectiveness.  

PubMed

In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral- and neural-based explanations of reinforcement. We argue that HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009; Rankin etal., 2009). We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow) normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect "accelerated-HRE." Consideration of HRE is important for the development of effective reinforcement-based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior. PMID:24409128

Lloyd, David R; Medina, Douglas J; Hawk, Larry W; Fosco, Whitney D; Richards, Jerry B

2014-01-01

300

Pressure effect on the electronic transport properties of Fe1+yTe1-xSex  

NASA Astrophysics Data System (ADS)

We present a systematic study of electronic transport as function of pressure up to 25 kbar of Fe+yTe1-xSex single crystalline samples (with y=0.02, 0.05, and x=0, 0.2, and 0.3). Pressure is demonstrated to be a clean control parameter to drive the system with high Fe-excess through the metal-insulator (MIT) transition, in analogy with increasing the Se-doping or reducing the Fe-excess. The scaling of resistivity ?(T, p) below 50 K identified a critical pressure of pc=8 kbar which separates non-metallic and metallic temperature dependences. At the pc the low-temperature sheet resistance is in the 6.5 k?/square range. The Seebeck coefficient (S) at pc changes sign from negative to positive indicating a change in the electronic structure and in the balance between the electron and hole carriers. The S at the highest pressure exhibits low positive values similar to the metallic, superconducting cuprates. The critical MIT behavior, related to a quantum phase transition, indicates a universality of the Fe- and Cu-based high-Tc superconductors.

Arsenijevi?, Stevan; Gaál, Richard; Rønnow, Henrik; Viennois, Romain; Giannini, Enrico; van der Marel, Dirk; Forró, László

2012-02-01

301

Magnon gap formation and charge density wave effect on thermoelectric properties in SmNiC2 compound  

NASA Astrophysics Data System (ADS)

We studied the magnetic, electrical, and thermal properties of polycrystalline compound of SmNiC2. The electrical resistivity and magnetization measurement show the interplay between the charge density wave at TCDW = 157 K and the ferromagnetic ordering of Tc = 18 K. Below the ferromagnetic transition temperature, we observed the magnon gap formation of 4.3 ˜ 4.4 meV by ?(T) and Cp(T) measurements. The charge density wave is attributed to the increase of Seebeck coefficient resulting in the increase of power factor S^2?. The thermoelectric figure-of-merit ZT significantly increases due to the increase of power factor at TCDW = 157 K. Here we argue that the competing interaction between electron-phonon and electron-magnon couplings exhibits the unconventional behavior of electrical and thermal properties. This research was supported by Basic Science Research Program (2011-0021335), Nano-Material Technology Development Program (2011-0030147), and Mid-career Research Program (Strategy) (No. 2012R1A2A1A03005174) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology.

Kim, Jin-Hee; Rhyee, Jong-Soo; Kwon, Yong Seung

2013-03-01

302

Studies in MBO effectiveness.  

PubMed

Management by objectives (MBO) is a popular management approach the efficacy of which has been seriously questioned recently. I have analyzed 185 studies for the effects of MBO on employee productivity and/or job satisfaction. Research support for MBO was found to be inversely related to the degree of research design sophistication. Although the five well-controlled experiments leaned toward finding MBO to be ineffective, it appears a contingency approach to MBO is more appropriate than a definitive affirmation or rejection of MBO effectiveness. PMID:10298234

Kondrasuk, J N

1981-07-01

303

Extrapyramidal effects of neuroleptics.  

PubMed Central

A study was conducted on 66 psychiatric inpatients who took major tranquilizers for periods of four to 16 years. The frequency of signs of Parkinsonism and the effects of orphenadrine on these were studied in a double-blind crossover method. Sixty-one per cent of the patients showed signs of Parkinsonism. Female patients and those with organic brain pathology more frequently exhibited Parkinsonism (although the difference was not statistically significant). No correlation was found between duration of treatment and extrapyramidal effects. Of the 40 patients who developed Parkinsonism, 25 responded favourably to orphenadrine, while six (15%) had more marked manifestations on orphenadrine than on placebo. PMID:11277

Korczyn, A D; Goldberg, G J

1976-01-01

304

Anticancer effects of fucoidan.  

PubMed

Recently, there has been an increased interest in the pharmacologically active natural compounds isolated and used for remedies of various kinds of diseases, including cancer. The great deal of interest has been developed to isolate bioactive compounds from marine resources because of their numerous health beneficial effects. Among marine resources, marine algae are valuable sources of structurally diverse bioactive compounds. Fucoidan is a sulfated polysaccharide derived from brown seaweeds and has been used as an ingredient in some dietary supplement products. Fucoidan has various biological activities including antibacterial, antioxidant, anti-inflammatory, anticoagulant, and antitumor activities. So this chapter deals with anticancer effects of fucoidan. PMID:25081084

Senthilkumar, Kalimuthu; Kim, Se-Kwon

2014-01-01

305

Chiral magnetic effect  

SciTech Connect

Topological charge changing transitions can induce chirality in the quark-gluon plasma by the axial anomaly. We study the equilibrium response of the quark-gluon plasma in such a situation to an external magnetic field. To mimic the effect of the topological charge changing transitions we will introduce a chiral chemical potential. We will show that an electromagnetic current is generated along the magnetic field. This is the chiral magnetic effect. We compute the magnitude of this current as a function of magnetic field, chirality, temperature, and baryon chemical potential.

Fukushima, Kenji [Yukawa Institute, Kyoto University, Kyoto (Japan); Kharzeev, Dmitri E.; Warringa, Harmen J. [Department of Physics, Brookhaven National Laboratory, Upton New York 11973 (United States)

2008-10-01

306

Effective Nonlocal Euclidean Gravity  

E-print Network

A nonlocal form of the effective gravitational action could cure the unboundedness of euclidean gravity with Einstein action. On sub-horizon length scales the modified gravitational field equations seem compatible with all present tests of general relativity and post-Newtonian gravity. They induce a difference in the effective Newton's constant between regions of space with vanishing or nonvanishing curvature scalar (or Ricci tensor). In cosmology they may lead to a value $\\Omega<1$ for the critical density after inflation. The simplest model considered here appears to be in conflict with nucleosynthesis, but generalizations consistent with all cosmological observations seem conceivable.

C. Wetterich

1997-04-18

307

Modeling Hofmeister Effects  

PubMed Central

A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A.

2009-01-01

308

The constraint effective potential  

NASA Astrophysics Data System (ADS)

Because of the non-perturbative nature of the conventional effective potential ?(?, ?¯) (for classical Higgs potentials and volume ?) and because of the inconvenience of a Legendre transform for numerical computations, it is proposed to replace ?(?, ?¯) by a "constraint" effective potential U(?, ?¯), which has a direct intuitive meaning, which is very convenient for lattice computations, and from which ?(?, ?¯) can immediately be recovered (as the convex hull). In particular, ?(?, ?¯) = U(?, ?¯). Various properties of U(?, ?¯), such as convexity properties, upper and lower bounds and volume dependence are established. It is computed directly for zero dimensions and by Monte Carlo simulations in one and four dimensions, with up to 160 and 8 4 lattice sites, respectively.

O'Raifeartaigh, L.; Wipf, A.; Yoneyama, H.

1986-06-01

309

Contamination effects study  

NASA Technical Reports Server (NTRS)

The in-situ optical surface measurement system is a facility designed to study the deleterious effects of particulate materials on the surface reflectivities of optical materials in the vacuum ultraviolet (VUV). This arrangement is designed to simulate the on-orbit effects of contamination and degradation of optical surfaces. This simulation is accomplished through the use of non-coherent VUV sources illuminating optical surfaces located in a high vacuum chamber. Several sources of contamination are employed. The reflectivity is measured both at the specular reflection as well as at two scattered positions, forward and reverse. The system components are described and an operating procedure is given.

1988-01-01

310

Modeling Hofmeister Effects.  

PubMed

A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A

2009-03-11

311

Health Effects of Wood Smoke  

MedlinePLUS

... Radiation Burn Wise Consumers Health Effects Consumers - Health Effects Subscribe to BurnWise Click image to enlarge Smoke ... exposure can lead to a variety of health effects. For example, numerous studies link particle levels to ...

312

Side Effects of Hormone Therapy  

MedlinePLUS

... PCF Spotlight Glossary African American Men Living with Prostate Cancer Side Effects of Hormone Therapy Side Effects Urinary ... to evaluate its use in men with advanced prostate cancer. If the approach proves to be as effective ...

313

Health Effects of Noise Pollution  

MedlinePLUS

... effects of noise pollution Health effects of noise pollution People of all ages, including children, teens, young ... noises around them. The health effects of noise pollution include: Hearing loss. Noise-induced hearing loss usually ...

314

Health Effects of Air Pollution  

MedlinePLUS

... Health effects of air pollution Health effects of air pollution Breathing air that is not clean can hurt ... important to know about the health effects that air pollution can have on you and others. Once you ...

315

Enhanced thermoelectric performance in zinc substituted p-type filled skutterudites CeFe{sub 4-x}Zn{sub x}Sb{sub 12}  

SciTech Connect

In this study, Zn-substituted polycrystalline skutterudites CeFe{sub 4-x}Zn{sub x}Sb{sub 12} (x=0, 0.05, 0.1, 0.2, 0.3) were successfully prepared by a traditional melting-annealing method. The solubility of Zn in Fe site is {approx}1.2%, exceeding which trace amount of ZnSb phase can be detected in the XRD. This ZnSb impurity phase, with size of several hundred nanometers for the sample with x=0.2 but showing surprisingly small size of {approx}10 nm for the sample with x=0.3, selectively distributes on the grain boundaries. In particular, the introduction of Zn in Fe site effectively improves the Seebeck coefficient in a manner of enhancement in hole effective mass, but it has negligible influence on both electrical and thermal conductivities though the hole concentration is increased. Consequently the corresponding improvement in power factor leads to an improved thermoelectric figure of merit (ZT) of 0.9 at 800 K for the sample with x=0.1, which is {approx}15% higher than that of Zn-free sample. This study demonstrates a favorable effect of Zn iso-substitution and opens a new strategy to improve the thermoelectric properties of p-type Fe-based skutterudites beyond the sole phonon engineering. - Graphical abstract: (a)-(c) ZnSb nanoinclusions emerge when Zn exceeds its solubility limit. (d), (e) The introduction of Zn boosts the Seebeck coefficient and thus enhances the ZT value. Highlights: Black-Right-Pointing-Pointer Zn is successfully employed to substitute Fe atom for the first time. Black-Right-Pointing-Pointer ZnSb nanoinclusions emerge when Zn exceeds its solubility limit {approx}0.12. Black-Right-Pointing-Pointer The introduction of Zn boosts the Seebeck coefficient and enhances the ZT value.

Tan Gangjian; Wang Shanyu; Li Han; Yan Yonggao [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Hongshan district, Wuhan 430070 (China); Tang Xinfeng, E-mail: tangxf@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Hongshan district, Wuhan 430070 (China)

2012-03-15

316

Exploring the relationship between celebrity endorser effects and advertising effectiveness A quantitative synthesis of effect size  

Microsoft Academic Search

This study provides a quantitative summary of the relationship between celebrity endorser source effects and effectiveness in advertising. The Kruskal-Wallis non- parametric test is used to identify the most influential celebrity endorser source effects on effectiveness. The role of celebrity\\/product fit, interaction effects, sample type, study setting, and country of study are also included as moderators. Results suggest negative celebrity

Clinton Amos

317

What Effective Schools Do  

ERIC Educational Resources Information Center

Research has been showing that the most important development in K-12 education over the past decade has been the emergence of a growing number of urban schools that have been convincingly shown to have dramatic positive effects on the achievement of disadvantaged students. Those with the strongest evidence of success are oversubscribed charter…

West, Martin R.; Gabrieli, Christopher F. O.; Finn, Amy S.; Kraft, Matthew A.; Gabrieli, John D. E.

2014-01-01

318

Desert Storm environmental effects  

Microsoft Academic Search

It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide

E. W. Kimball

1992-01-01

319

Conditional Effects in Graphplan  

Microsoft Academic Search

Graphplan has attracted considerable interest because of its extremely high performance, but the algorithm's inability to handle action representations more expressive than STRIPS is a major limitation. In particular, extending Graphplan to handle conditional effects is a surprisingly subtle enterprise. In this paper, we describe the space of possible alternatives, and then concentrate on one particular approach we call factored

Corin R. Anderson; David E. Smith; Daniel S. Weld

1998-01-01

320

FIELD DISPERSANT EFFECTIVENESS TEST  

EPA Science Inventory

The EPA's OHMSETT facility has developed a rapid field test that includes some of the theoretical aspects and conditions of dispersion at sea. This Field Dispersant Effectiveness Test (FDET) has been used to evaluate the dispersibility of various commonly-transported oils and mak...

321

Media effect in commercial  

Microsoft Academic Search

Keywords Brand identity, Brand image, Consumer behaviour, Goodwill, Marketing communications, Sponsorship Abstract Various elements of brand identity contribute to brand image development; however, the role of marketing communications is particularly important in achieving brand image effects. In the case of advertising, two separate elements of communications, a message and a medium, combine to deliver particular brand image values. In the

David Shipley

322

Defending Double Effect  

Microsoft Academic Search

According to the doctrine of double effect(DDE), there is a morally significantdifference between harm that is intended andharm that is merely foreseen and not intended.It is not difficult to explain why it is bad tointend harm as an end (you have a ``badattitude'' toward that harm) but it is hard toexplain why it is bad to intend harm as a

Alison Hills

2003-01-01

323

Rainfall Effects Acknowledgements  

E-print Network

and falling water table Constant hydraulic gradient Air Flowlines Displaced Vapor plume Dissolved plume Rain Schulte - Colorado School of Mines Michael Glatthar - US Air Force Academy Effects of Water Table for Disposal of Radioactive Waste, Wettingen, Switzerland Introduction Objectives Water Table Fluctuation

324

Camp's "Disneyland" Effect.  

ERIC Educational Resources Information Center

Describes the positive mental, physical, and social growth impacts that the camping experience had on the author, and urges camp program evaluation to plan and implement such changes. Sidebar lists steps of effective evaluation: program goals and objectives, goals of evaluation, implementation of evaluation, data analysis, and findings and…

Renville, Gary

1999-01-01

325

Effective Online Privacy Policies  

Microsoft Academic Search

Online privacy policies are important mechanisms for informing web site users about the level of information privacy protection afforded when visiting web sites. To date, societal mechanisms and technologies have been the focus of attempts to improve the quality and effectiveness of online privacy policies. Little attention, however, has been given to the development and use of organisational measures for

Sharman Lichtenstein; Paula M C Swatman; Kanchan Babu

326

Explaining Charter School Effectiveness  

ERIC Educational Resources Information Center

This study uses entrance lotteries to explore heterogeneity in the achievement effects of charter schools across demographic groups and between urban and non-urban areas in Massachusetts. The authors develop a framework for interpreting this heterogeneity using both student- and school-level explanatory variables. (Contains 4 tables.)

Angrist, Joshua D.; Pathak, Parag A.; Walters, Christopher R.

2012-01-01

327

Effective sample labeling  

Microsoft Academic Search

Ground-water samples collected by the Pacific Northwest Laboratory (PNL) for hazardous waste and radiological monitoring programs have come under strict regulatory and quality assurance requirements as a result of laws such as the Resource Conservation and Recovery Act. Before these laws were in effect, sample collection consisted mainly of filling a single plastic bottle that was then submitted for limited

J. T. Reiger; R. W. Bryce

1989-01-01

328

Courtside: Private Effects?  

ERIC Educational Resources Information Center

After being accused of sexually harassing a student, a high school math teacher in New York was suspended with pay pending an impartial hearing. The district allowed the teacher to return to his classroom to collect his personal effects, which he had kept in boxes, desk drawers, and three filing cabinets, one of which was locked. He did not…

Zirkel, Perry A.

2004-01-01

329

Reporting Research Results Effectively  

ERIC Educational Resources Information Center

Assessment research is at its best when it packages research results and data so that they can be digested by multiple audiences. Too many assessment researchers spend all their efforts planning and executing the research project with little attention to closing the loop at the end. If assessment findings are not communicated effectively, the…

Volkwein, J. Fredericks

2010-01-01

330

Tips for Effective Management  

ERIC Educational Resources Information Center

School business officials' days are filled with numbers and reports--audits, balance sheets, check registers, financial statements, journal entries, vouchers, and warrant reports, just to name a few. Those are all important tools that school business officers use to manage the financial resources of the district effectively. However, they are also…

Supple, Kevin F.

2009-01-01

331

Earth Impacts Effects Program  

NSDL National Science Digital Library

This interactive web site estimates the regional environmental consequences of an impact on Earth. The program will estimate the ejecta distribution, ground shaking, atmospheric blast wave, and thermal effects of an impact as well as the size of the crater produced.

Marcus, Robert; Melosh, H. J.

332

Effects of nuclear war  

SciTech Connect

The author reviews the subject rising the following topics and subtopics: I. Nuclear explosions: heat, nuclear radiation, and radioactive fallout; II. Effects: radiation sickness, burns, blast injuries, and equivalent areas of death; III. Nuclear war: battlefield, regional, intercontinental - counterforce, and intercontinental - counter-city and industry. There are two appendices. 34 references, 32 figures.

von Hippel, F.

1983-01-01

333

Documentation: Effective AND Literate  

Microsoft Academic Search

The purpose of this paper is to show how documentation can be literate, in a stylistic sense, and still be effective. Literate prose is a powerful tool that, when properly used in computer documentation, can take advantage of the full power of the English language. This does not mean that all computer documentation must or can read like a Nobel

Paul S. Burdett Jr.

1985-01-01

334

Humor and group effectiveness  

Microsoft Academic Search

Despite the importance of groups in the workplace and the demand from workers for a fun work environment, there is no model that explains how successful organizational humor can impact work groups. The purpose of this article is to present a model, based on Hackman's framework of group effectiveness, that can be used to understand the relationship between successful organizational

Eric Romero; Anthony Pescosolido

2008-01-01

335

Cardiovascular effects of alcohol.  

PubMed Central

The effects of alcohol on the heart include modification of the risk of coronary artery disease, the development of alcoholic cardiomyopathy, exacerbation of conduction disorders, atrial and ventricular dysrhythmias, and an increased risk of hypertension, hemorrhagic stroke, infectious endocarditis, and fetal heart abnormalities. PMID:2686174

Davidson, D M

1989-01-01

336

EMERGENCY MANAGEMENT Effective Date  

E-print Network

SUBJECT: EMERGENCY MANAGEMENT Effective Date: 4-7-14 Policy Number: 1.14 Supersedes: Policy 4- made, by implementing appropriate emergency management policies, plans, and procedures designed.001. In the absence of specific regulatory mandates for particular situations, best emergency management practices

Fernandez, Eduardo

337

Effective management through delegation  

Microsoft Academic Search

Management is concerned with the pulling together of resources so that jobs are done efficiently and objectives are met within the time-scale laid down. Of prime importance among those resources are the people involved – effective management of people is essential if we are to take full advantage of their skills and aptitudes. It is not just a question of

John Muir

1995-01-01

338

The Anrep Effect Reconsidered  

PubMed Central

Evidence is presented supporting the hypothesis that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed. Major evidence consists of data obtained from an isolated heart preparation showing that the Anrep effect can be abolished with coronary vasodilation, and that with an abrupt increase in systolic pressure there is a significant reduction in the distribution of coronary flow to subendocardial layers of the ventricle. Furthermore, the intracardiac electrocardiogram shows S-T segment and T wave changes after an abrupt increase in ventricular pressure similar to that noted after coronary constriction. Major implications are that normally there may be ischemia of the subendocardial layers tending to reduce myocardial contractility which may account, in part, for the positive inotropic effect of various coronary vasodilators; that with an abrupt increase in ventricular pressure the subendocardium is rendered temporarily ischemic, placing the heart in jeopardy from arrhythmias until this is corrected; and that end-diastolic pressure and the intracardiac electrocardiogram may provide a means of evaluating the adequacy of circulation to subendocardial layers in diseased ventricles when systolic pressure is abruptly increased. PMID:5056656

Monroe, R. G.; Gamble, W. J.; Lafarge, C. G.; Kumar, A. E.; Stark, J.; Sanders, G. L.; Phornphutkul, C.; Davis, M.

1972-01-01

339

Managing the Effective University.  

ERIC Educational Resources Information Center

Evidence from the literature of college administration in a changing environment points to the critical role of academic leadership in maintaining morale, enhancing productivity, and helping staff welcome momentous change. Tomorrow's effective universities will require academic managers whose leadership qualities resemble those of good teachers in…

Ramsden, Paul

1998-01-01

340

Alcohol's Effects on Adolescents  

Microsoft Academic Search

uring adolescence, many people begin to experi­ ment with alcohol, yet relatively little is known about alcohol's effects on this critical stage of development. We do know that early initiation of alcohol use remains one of the most powerful predictors of later alcohol abuse (Grant 1998). We also know that during adolescence changes occur in the regions of the brain

Linda Patia Spear

2002-01-01

341

Effectively Communicating Qualitative Research  

ERIC Educational Resources Information Center

This article is a guide for counseling researchers wishing to communicate the methods and results of their qualitative research to varied audiences. The authors posit that the first step in effectively communicating qualitative research is the development of strong qualitative research skills. To this end, the authors review a process model for…

Ponterotto, Joseph G.; Grieger, Ingrid

2007-01-01

342

Reading and Writing Effectively.  

ERIC Educational Resources Information Center

This workbook, designed for workplace literacy courses, covers effective reading and writing. Introductory materials include objectives, a topical outline, sources, and information on time for the course and continuing education credits. The 16 sessions of the course cover the following topics: job terms; abbreviations, acronyms, and pictorial…

Lewandowski, Carol; Burt, Lorna

343

Tips for Effective Negotiating  

Microsoft Academic Search

Negotiation is a valuable skill in every part of your life. When carried out effectively negotiation can produce an outcome that is mutually beneficial for both parties. Negotiation is most enjoyable when both parties think they have gained something and when both parties have developed a positive working relationship. Since many of your negotiations at work and at home involve

Nikisha Williams; Virginia Valian

344

Interactive Pi Bonding Effects  

NSDL National Science Digital Library

This application demonstrates the effect of pi bonding on the one-electron ligand field splitting in an octahedral. By clicking on the appropriate buttons students can see how D changes when you move from ligands with no pi bonding capability to pi donor and pi acceptor ligands.

345

Tracking the Effectiveness of  

E-print Network

of Usability Evaluation Methods Abstract We present a case study that tracks usability problems predictedTracking the Effectiveness of Usability Evaluation Methods Bonnie E. John & Steven J. Marks* 12 contained in this document are those of the author and should not be interpreted as representing

346

Physiological effects of hypnosis  

Microsoft Academic Search

There are many studies indicating that sensory, circulatory, gastrointestinal, and cutaneous functions can be altered by means of hypnosis. There also are many studies indicating that similar physiological effects can be produced by symbolic stimulation without hypnosis. The assumption that hypnotic behavior is a function of the trance state is open to question. From Psyc Abstracts 36:01:3II90B.

Theodore Xenophon Barber

1961-01-01

347

Adverse effects of benzodiazepines  

Microsoft Academic Search

The growing realisation that the benzodiazepines have potential for causing serious harm has caused concern due to their wide and common use. This has stimulated interest in the costs and benefits of their use. This paper is a review of the adverse effects of benzodiazepines, and concentrates on four areas of particular concern: drug dependence which the consequent withdrawal symptoms;

Claire Gudex

1990-01-01

348

Cost Effective Prototyping  

NASA Technical Reports Server (NTRS)

This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

Wickman, Jerry L.; Kundu, Nikhil K.

1996-01-01

349

EFFECTS ON SALTWATER ORGANISMS  

EPA Science Inventory

The literature review summarizes current data on the effects of pesticides and metals on marine organisms, aquatic environmental research methods, bioaccumulation of pollutants by estuarine and marine organisms and in water/sediment residues and biota. Results of studies of the e...

350

Measuring Teacher Effectiveness  

ERIC Educational Resources Information Center

Prior research has shown that there is a correlation between teacher characteristics (e.g., pedagogical knowledge, teacher preparation/certification) and student achievement. Current political contexts call for the utilization of student achievement data to measure the effectiveness of our education systems. A solid research base of how teacher…

Jacobo, Amber Leann

2012-01-01

351

Lorenz Attractor -- Butterfly Effect  

NSDL National Science Digital Library

The "Butterfly Effect", or more technically the "sensitive dependence on initial conditions", is the essence of chaos. This is illustrated an applet of the Lorenz Attractor. The demonstration shows a graphical representation of the time variation of three variables X(t),Y(t) and Z(t), coupled by non-linear evolution equations.

Michael Cross, Cal T.

352

Revisiting Effective Teaching.  

ERIC Educational Resources Information Center

Discusses connections between Madeline Hunter's elements of effective teaching and current brain research. Hunter's emphasis on setting the stage for learning fits precisely with research on the brain's attentional mechanisms. Other Hunter elements, including level of concern (challenge), task analysis, procedural memory, and prior learning, are…

Wolfe, Pat

1998-01-01

353

Psychotropic effects of thymogen  

Microsoft Academic Search

Effects of thymogen on the behavior of mice were studied, and the results obtained suggest that this immunomodulator possesses\\u000a psychostimulatory, antidepressive, and stress-protecting properties which open up new prospects for the use of thymic peptides\\u000a in psychiatry.

T. I. Nevidimova; N. I. Suslov

1995-01-01

354

Measuring Institutional Effectiveness.  

ERIC Educational Resources Information Center

The measurement of institutional effectiveness involves a systematic comparison of organizational purpose and performance. For community colleges, organizational purpose can be defined in terms of providing access to education, realizing student achievement, promoting student development, or addressing social needs. If all four purposes are…

Macomb County Community Coll., Warren, MI.

355

Effectiveness Review Analysis (Insert Effectiveness Review Name) Root Cause  

E-print Network

Effectiveness Review Analysis ­ (Insert Effectiveness Review Name) 1 of 1 Root Cause: Corrective: · Effective (Yes)--Corrective actions are implemented as intended, have addressed the causes of the issue the causes of the issue / finding, does not effectively prevent recurrence of the issue / finding, and does

356

Long-term effectiveness and side effects of laser resurfacing  

NASA Astrophysics Data System (ADS)

Laser resurfacing have been used for treatment of photoaged facial skin since 1994. Very few long-term follow-up studies regarding the effectiveness and side effects of the laser resurfacing exist. We investigated the long-term effectiveness and side effects of laser resurfacing in our patients who underwent this procedure since our pioneering invention.

Manuskiatti, Woraphong; Fitzpatrick, Richard E.; Goldman, Mitchel P.; Krejci-Papa, Niels

1998-07-01

357

Graphene nanoribbon thermopower as a tool for molecular spectroscopy  

NASA Astrophysics Data System (ADS)

In this work, we study thermoelectric properties of graphene nanoribbons with side-attached organic molecules. By adopting a single-band tight binding Hamiltonian and the Green's function formalism, we calculated the transmission and Seebeck coefficients for different hybrid systems. The corresponding thermopower profiles exhibit a series of sharp peaks at the eigenenergies of the isolated molecule indicating that the system can be proposed as a molecular thermo-device. We have studied the effects of the temperature on the thermoelectric response, and considered random configurations of molecule distributions, in different disorder regimes. We have found that the main features of the thermopower are robust under temperature and disorder.

Rosales, L.; Nunez, C. D.; Pacheco, M.; Latgé, A.; Orellana, P. A.

2013-10-01

358

Lattice thermal conductivity diminution and high thermoelectric power factor retention in nanoporous macroassemblies of sulfur-doped bismuth telluride nanocrystals  

NASA Astrophysics Data System (ADS)

We report ultralow lattice thermal conductivity in the 0.3 ? ?L ? 0.6 W m-1 K-1 range in nanoporous bulk bismuth telluride pellets obtained by sintering chemically synthesized nanostructures, together with single-crystal-like electron mobilities and Seebeck coefficients at comparable charge carrier concentrations. The observed ?L is up to 35% lower than classical effective medium predictions, and can be quantitatively explained by increased phonon scattering at nanopores and nanograins. Our findings are germane to tailoring nanoporous thermoelectric materials for efficient solid-state refrigeration, thermal energy harvesting, and thermal management applications.

Zhang, Yanliang; Mehta, Rutvik J.; Belley, Matthew; Han, Liang; Ramanath, Ganpati; Borca-Tasciuc, Theodorian

2012-05-01

359

Energy Conversion Efficiency of an Exponentially Graded Thermoelectric Material  

NASA Astrophysics Data System (ADS)

This work describes an analytical model that predicts the effects of property gradients on the energy conversion efficiency of a functionally graded thermoelectric material (FGTEM) with an exponentially varying Seebeck coefficient S, electrical resistivity ?, and thermal conductivity k. The figure-of-merit parameter, Z = S 2/( ?k), thus also varies exponentially. A closed-form solution for the temperature distribution in the FGTEM and the efficiency as a function of current density are obtained. The peak efficiency and the optimal current density are determined from the efficiency solution. It is found that the efficiency may be increased by about 30% using appropriate property gradients.

Jin, Zhi-He; Wallace, Travis T.; Lad, Robert J.; Su, Ji

2014-02-01

360

Thermoelectric power enhancement of PEDOT:PSS in high-humidity conditions  

NASA Astrophysics Data System (ADS)

We report an increase in the thermoelectric power factor of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) from 23 ± 5 to 225 ± 130 µW/(m·K2) in high-humidity conditions. This enhancement was caused mainly by an increase in the apparent Seebeck coefficient, which could be related to morphological change after water absorption or electrochemical reaction of PEDOT in air. Our results demonstrate a positive effect of water in the PEDOT:PSS system and indicate the need for well-controlled measurement conditions, particularly humidity, in evaluating the performance of conducting organic materials.

Wei, Qingshuo; Mukaida, Masakazu; Kirihara, Kazuhiro; Naitoh, Yasuhisa; Ishida, Takao

2014-03-01

361

Electrical and electrothermal transport in InN: The roles of defects  

NASA Astrophysics Data System (ADS)

The transport properties of Mg doped and undoped InN films are studied with capacitance-voltage, thermopower, and Hall mobility measurements. A positive Seebeck coefficient is observed for Mg doped InN confirming p-type conductivity, though high doping and structural defect density can lead to n-type films. Transport measurements of undoped films are analyzed employing Rode's iterative Boltzmann equation method. Observed thermopower, Hall mobility, and dislocation density data for undoped films are consistent with calculations including the effects of charged line defect (donor-type dislocation) scattering.

Miller, N.; Ager, J. W.; Jones, R. E.; Smith, H. M.; Mayer, M. A.; Yu, K. M.; Hawkridge, M. E.; Liliental-Weber, Z.; Haller, E. E.; Walukiewicz, W.; Schaff, W. J.; Gallinat, C.; Koblmüller, G.; Speck, J. S.

2009-12-01

362

Thermopower and conductivity activation energies in hydrogenated amorphous silicon  

SciTech Connect

The long range fluctuation model has been widely used to account for the difference in activation energies seen experimentally in dark conductivity and thermopower measurements in hydrogenated amorphous silicon. The authors report on a test of this model using measurements of the conductivity and thermoelectric effects carried out in both open and short circuit configurations. While the thermopower activation energy is less than that of the dark conductivity, the short circuit Seebeck conductivity is found to be nearly identical to the dark conductivity in both activation energy and magnitude, consistent with the long range fluctuation model.

Dyalsingh, H.M.; Kakalios, J. [Univ. of Minnesota, Minneapolis, MN (United States). School of Physics and Astronomy

1996-12-31

363

Structural Characterization and Thermoelectric Properties of Hot-Pressed CoSi Nanocomposites  

NASA Astrophysics Data System (ADS)

Fabrication of nanocomposites by introduction of SiO2 metal oxide nanoparticles into a cobalt silicide thermoelectric matrix is studied. The CoSi matrix material was prepared through solid-state synthesis, and the nano-SiO2 metal oxide was introduced by mechanical grinding. The mixed powders were hot pressed to fabricate nanocomposites. The structural and morphological modifications were studied by powder x-ray diffraction analysis and scanning electron microscopy. The thermoelectric properties of the materials were followed through the Hall effect, Seebeck coefficient, and electrical and thermal conductivities in the temperature range from 300 K to 1000 K.

Ioannou, Maria; Symeou, Elli; Giapintzakis, John; Kyratsi, Theodora

2014-10-01

364

Thermomicrocapillaries as temperature biosensors in single cells  

NASA Astrophysics Data System (ADS)

Temperature is an important physical parameter in biology and its deviation from optimum can cause damage in biosystems. Thermocouples based on the Seebeck effect can be structured on glass microcapillaries to obtain thermomicrocapillaries (TMCs) usable in a micromanipulation setup. The suitability of the setup was proven by monitoring the temperature increase upon illumination of leaves and single cells following insertion of the TMC. The increase was 1.5 K in green tissue and 0.75 K in white leaf sections due to lower absorption. In single cells of trichomes, the increase was 0.5 K due to heat dissipation to the surrounding air.

Herth, Simone; Giesguth, Miriam; Wedel, Waldemar; Reiss, Günther; Dietz, Karl-Josef

2013-03-01

365

Structural Characterization and Thermoelectric Properties of Hot-Pressed CoSi Nanocomposites  

NASA Astrophysics Data System (ADS)

Fabrication of nanocomposites by introduction of SiO2 metal oxide nanoparticles into a cobalt silicide thermoelectric matrix is studied. The CoSi matrix material was prepared through solid-state synthesis, and the nano-SiO2 metal oxide was introduced by mechanical grinding. The mixed powders were hot pressed to fabricate nanocomposites. The structural and morphological modifications were studied by powder x-ray diffraction analysis and scanning electron microscopy. The thermoelectric properties of the materials were followed through the Hall effect, Seebeck coefficient, and electrical and thermal conductivities in the temperature range from 300 K to 1000 K.

Ioannou, Maria; Symeou, Elli; Giapintzakis, John; Kyratsi, Theodora

2014-06-01

366

Thermoelectric properties of n-type polycrystalline BixSb2-xTe3 alloys  

NASA Technical Reports Server (NTRS)

(BixSbl-x)2Te3(.5 = x = .7) polycrystalline samples were synthesized using a combination of melting and powder metallurgy techniques. The samples were hot pressed in graphite dies and cut perpendicular and parallel to the pressing direction. Samples were examined by microprobe analysis to determine their atomic composition. The thermoelectric properties were measured at room temperature in both directions. These properties include Seebeck coefficient, thermal conductivity, electrical resistivity, and Hall effect. The thermoelectric figure-of-merit, ZT, was calculated fiom these properties.

Snyder, J.; Gerovac, N.; Caillat, T.

2002-01-01

367

Enhanced room temperature electronic and thermoelectric properties of the dilute bismuthide InGaBiAs  

SciTech Connect

We report room temperature electronic and thermoelectric properties of Si-doped In{sub 0.52}Ga{sub 0.48}Bi{sub y}As{sub 1-y} with varying Bi concentrations. These films were grown epitaxially on a semi-insulating InP substrate by molecular beam epitaxy. We show that low Bi concentrations are optimal in improving the conductivity, Seebeck coefficient, and thermoelectric power factor, possibly due to the surfactant effects of bismuth. We observed a reduction in thermal conductivity with increasing Bi concentration, which is expected because of alloy scattering. We report a peak ZT of 0.23 at 300 K.

Dongmo, Pernell; Zhong Yujun; Bomberger, Cory; Zide, Joshua [Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); Attia, Peter [Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Cheaito, Ramez; Hopkins, Patrick E. [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 2294 (United States); Ihlefeld, Jon F. [Sandia National Laboratories, P.O. Box 5800, M.S. 1069, Albuquerque, New Mexico 87185 (United States)

2012-11-01

368

Low-Temperature Drift in MIMS Base-Metal Thermocouples  

NASA Astrophysics Data System (ADS)

Inhomogeneities are known to develop within thermoelements exposed to elevated temperatures, resulting in temperature measurement errors. While the Seebeck coefficient drift in base-metal thermocouples due to aging at temperatures over has been extensively investigated, there have been very few investigations into possible Seebeck changes at lower temperatures. Despite warnings about possible effects, most practitioners assume changes in homogeneity are either not significant or not able to develop at temperatures less than . This study reports on measurements of inhomogeneities in base-metal thermocouples arising from heat treatment at temperatures in the region of . Thermoelectric scans of thermocouples were carried out following exposure of a range of mineral-insulated metal-sheathed base-metal thermocouples, from two large manufacturers, of Types E, J, K, N, and T, to either a linear-gradient furnace within the range of to or uniform temperature zones of , , and . The experiments reveal noticeable drift in all base-metal types for temperatures as low as and exposure times as short as 1 h. The most sensitive thermoelement alloys appear to be Constantan, Alumel, and Nicrosil. It is concluded that the common working assumption that base-metal thermocouples suffer no thermally induced changes in the Seebeck coefficient below is false. This observation has significant implications for many high-stability monitoring and control systems reliant on base-metal thermocouples that operate in the range of to . Additionally, thermoelectric scanning of base-metal thermocouples should be carried out at temperatures well below to avoid erasure of strain effects or imprinting of new thermal signatures.

Webster, E. S.

2014-04-01

369

The uniform rugosity effect  

E-print Network

Relying on the effect of microscopic asperities, one can mathematically justify that viscous fluids adhere completely on the boundary of an impermeable domain. The rugosity effect accounts asymptotically for the transformation of complete slip boundary conditions on a rough surface in total adherence boundary conditions, as the amplitude of the rugosities vanishes. The decreasing rate (average velocity divided by the amplitude of the rugosities) computed on close flat layers is definitely influenced by the geometry. Recent results prove that this ratio has a uniform upper bound for certain geometries, like periodical and ”almost Lipschitz ” boundaries. The purpose of this paper is to prove that such a result holds for arbitrary (non-periodical) crystalline boundaries and general (non-smooth) periodical boundaries.

unknown authors

370

The Uniform Rugosity Effect  

NASA Astrophysics Data System (ADS)

Relying on the effect of microscopic asperities, one can mathematically justify that viscous fluids adhere completely on the boundary of an impermeable domain. The rugosity effect accounts asymptotically for the transformation of complete slip boundary conditions on a rough surface in total adherence boundary conditions, as the amplitude of the rugosities vanishes. The decreasing rate (average velocity divided by the amplitude of the rugosities) computed on close flat layers is definitely influenced by the geometry. Recent results prove that this ratio has a uniform upper bound for certain geometries, like periodical and "almost Lipschitz" boundaries. The purpose of this paper is to prove that such a result holds for arbitrary (non-periodical) crystalline boundaries and general (non-smooth) periodical boundaries.

Bonnivard, Matthieu; Bucur, Dorin

2012-06-01

371

[Hypertensive effects of qat].  

PubMed

Chewing of Qat leaves which contain amphetamine alkaloids is a traditional drug practice in the horn of Africa. Cathine and cathinone are responsible for the desired psychogenic (suppression of hunger, mind stimulation, euphoria) and sympathicomimetic effects. In this study, we monitored seven volunteers during a traditional qat ritual. An increase in systolic and diastolic pressure was observed in three patients including one presenting predisposing chronic arterial hypertension. Peak pressure was observed approximately seven hours after beginning the ritual. The three patients presenting pressure changes were not significantly different from the four unaffected patients with regard to age or duration of qat use. These findings suggest that qat use by untreated hypertensive patients who react strongly to vasoconstrictive effects can lead to hypertension and resulting cardiovascular complications. PMID:10088104

Mion, G; Oberti, M; Ali, A W

1998-01-01

372

Leptophilic Effective WIMPs  

E-print Network

Effective WIMP models are minimal extensions of the standard model that explain the relic density of dark matter by the ``WIMP miracle.'' In this paper we consider the phenomenology of effective WIMPs with trilinear couplings to leptons and a new ``lepton partner'' particle. The observed relic abundance fixes the strength of the cubic coupling, so the parameters of the models are defined by the masses of the WIMP and lepton partner particles. This gives a simple parameter space where collider and direct detection experiments can be compared under well-defined physical minimality assumptions. The most sensitive collider probe is the search for leptons + MET, while the most sensitive direct detection channel is scattering from nuclei arising from loop diagrams. Collider and direct detection searches are highly complementary: colliders give the only meaningful constraint when dark matter is its own antiparticle, while direct detection is generally more sensitive if the dark matter is not its own antiparticle.

Spencer Chang; Ralph Edezhath; Jeffrey Hutchinson; Markus Luty

2014-02-28

373

Leptophilic Effective WIMPs  

E-print Network

Effective WIMP models are minimal extensions of the standard model that explain the relic density of dark matter by the ``WIMP miracle.'' In this paper we consider the phenomenology of effective WIMPs with trilinear couplings to leptons and a new ``lepton partner'' particle. The observed relic abundance fixes the strength of the cubic coupling, so the parameters of the models are defined by the masses of the WIMP and lepton partner particles. This gives a simple parameter space where collider and direct detection experiments can be compared under well-defined physical minimality assumptions. The most sensitive collider probe is the search for leptons + MET, while the most sensitive direct detection channel is scattering from nuclei arising from loop diagrams. Collider and direct detection searches are highly complementary: colliders give the only meaningful constraint when dark matter is its own antiparticle, while direct detection is generally more sensitive if the dark matter is not its own antiparticle.

Chang, Spencer; Hutchinson, Jeffrey; Luty, Markus

2014-01-01

374

Fuel Vaporization Effects  

NASA Technical Reports Server (NTRS)

A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

Bosque, M. A.

1983-01-01

375

Polarization effects. Volume 2  

SciTech Connect

The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

Courant, E.

1981-01-01

376

AHIS Cost-Effectiveness  

PubMed Central

In 1977, Fairfax Hospital Association (FHA) set out to determine the cost-effectiveness of installing a comprehensive Automated Hospital Information System (AHIS) within its institutions. In order to determine this, FHA developed a formalized staffing impact analysis methodology. The objective of the methodology is to determine the effect that any automated system will have on staffing requirements if the specific functions of the system are known in advance. This methodology was subsequently used in the evaluation of two departments - Radiology and Utilization Review. This paper describes the methodology used so that other institutions can benefit by the experience, and discusses why it is necessary to perform such an analysis, concentrating on determining whether a system is cost beneficial, identifying benefits in advance to ensure that they are in fact achieved later, and satisfying external reporting requirements. The bulk of the paper documents step-by-step how the analysis is performed.

Bunnell, Pamela; Lemons, Lorena F.; Shapin, Paul G.

1980-01-01

377

Doppler Effect Model  

NSDL National Science Digital Library

The Doppler Effect model demonstrates the shift in frequency of a wave that is produced by the motion of either the wave source or the observer of the wave (or both). In this simulation, you can explore the change in the wave that is produced by source and/or observer motion, and you can even view what the situation looks like from the perspective of the medium (the standard reference frame), the source, or the observer. The Doppler Effect model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_Doppler.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

378

Fire Effects Information System  

NSDL National Science Digital Library

The Fire Effects Information System (FEIS) provides up-to-date information about fire effects on plants and animals. It was developed at the USDA Forest Service Rocky Mountain Research Station's Fire Sciences Laboratory in Missoula, Montana. The FEIS database contains synoptic descriptions, taken from current English-language literature of almost 900 plant species, about 100 animal species, and 16 Kuchler plant communities found on the North American continent. The emphasis of each synopsis is fire and how it affects each species. Background information on taxonomy, distribution, basic biology and ecology of each species is also included. Synopses are thoroughly documented, and each contains a complete bibliography. Personnel from several land management agencies (USDA Forest Service, USDI-BIA, NPS, BLM, F&WS) identified the species to be included in the database. Those agencies funded the original work and continue to support maintenance and updating of the database.

1995-12-12

379

[Herbs and cardiotoxic effects].  

PubMed

Accidental or deliberate ingestion of poisonous herbs has become an increasingly common phenomenon over the last years. From existing literature data and case reports from emergency room visits or poison control centers, an overview is presented of the potential cardiotoxic manifestations following intoxication by wild herbal plants of the territory. The effects of the consumption of cardiac glycoside-containing plants (e.g., digitalis) are discussed along with tachyarrhythmias induced by Aconitum napellus L., Atropa belladonna L., Mandragora officinarum L. or Ephedra distachya L. herbs, and hypertensive crises associated with licorice abuse. For each plant, a brief historical and botanical background is provided, focusing on pathophysiology of intoxication and cardiotoxic effects on the basis of the most recent literature. Finally, medical management of intoxication, from both a general and cardiological viewpoint, is reviewed. PMID:23748541

Maffè, Stefano; Paffoni, Paola; Laura Colombo, Maria; Davanzo, Franca; Dellavesa, Pierfranco; Cucchi, Lorenzo; Zenone, Franco; Paino, Anna Maria; Franchetti Pardo, Nicolò; Bergamasco, Luca; Signorotti, Fabiana; Parravicini, Umberto

2013-06-01

380

NEURODEVELOPMENTAL EFFECTS OF COCAINE  

PubMed Central

The United States has recently been compelled to acknowledge and to cope with an alarming increase in incidence of drug exposure in newborns owing to a new cocaine epidemic. Perhaps because of the sudden onset of national recognition of the problem, the lack of a firm knowledge base regarding the mechanisms of the effects of cocaine on child development, and the sheer magnitude of the problem in urban areas of the United States, the issue of cocaine exposure in children has been characterized by medical, legal, and social policy controversies. This article focuses on elucidating what is and what is not known about cocaine’s neurodevelopmental effects and aims to inform perinatologists about the complex issues associated with understanding and caring for the cocaine-exposed newborn. PMID:8458168

Singer, Lynn; Arendt, Robert; Minnes, Sonia

2014-01-01

381

Tips for Effective Webinars  

Microsoft Academic Search

Giving an effective webinar requires some presentation redesign and technology skills that you don't necessarily need in a face-to-face presentation. A great speaker in a face-to-face environment can easily crash and burn in a webinar setting if he or she isn't prepared for the unique challenges and needs of that environment. Here are some tips to help you pull off

Maria H. Andersen

2010-01-01

382

Center for Effective Organizations  

Microsoft Academic Search

ABSTRACT In this chapter, we closely examine one set of factors that are critical for knowledge work team effectiveness --how organizations set and communicate,direction for teams. The variables we examine encompass,several related elements in the organization's direction-setting context: the clarity of the organization's strategy, the alignment of individual team, and organizational goals, and the measurability and specificity of those goals.

JAY R. GALBRAITH; SUSAN G. COHEN; CRISTINA B. GIBSON; JULIAN BIRKINSHAW

383

Identifying Effective School Principals  

E-print Network

focus on three dimensions: student performance, teacher retention, and financial management. Data is derived from the Texas Education Agency (TEA) to develop a total of seven specific indicators to measure success in these three areas for Texas... tests and school accountability ratings. TEA data is used from 1996-2005 to develop indicators for these two measures. Since our goal was to capture the improvements in student performance attributable to principal effectiveness, we used a value...

Fernandez, Kandyce; Flores, Santa; Huang, Emily; Igwe, Carolyn; McDonald, Leslie; Stroud, Ryan; Willis, Rebecca; Dugat, Amber

2007-01-01

384

Incubated reminiscence effects  

Microsoft Academic Search

Reminiscence, the recall of material that was not successfully recalled on a previous attempt, was examined in three experiments\\u000a as a function of the intertest (incubation) interval. Incubation intervals inserted between successive recall tests resulted\\u000a in increased reminiscence, but the effect was seen primarily in the first retested minute. Neither the duration of the initial\\u000a test (1–4 mm), nor the

Steven M. Smith; Edward Vela

1991-01-01

385

Transgenerational effects of NMs.  

PubMed

Nanomaterials are present in a number of commercially available products but there are uncertainties as to whether the unique properties that support their commercial use may also pose potential health risks. Information is missing concerning the influence of nanomaterials on the overall reproductive outcome and transgenerational effects in animals and plants. To obtain this information, long-term studies would be required using animal models phylogenetically close to humans and exposure conditions that reflect realistic scenarios with regard to dosages and admission. The nanoreprotoxicology literature published to date is largely descriptive in nature regarding the effects of nanoparticles. The mechanisms, which determine particle reproduction compatibility, are mostly elusive at the moment. Thus, it is recommended that future research explore the interactions between nanomaterials and transgenerational matter on a molecular level. It would, for instance, be of major importance to understand the behaviour of nanoparticles inside the cells but also their genotoxic and epigenetic effects. Recent studies have shown that intravenous and/or intra-abdominal administration of nanoparticles to mice results in their accumulation in the cells of many tissues, including the brain and the testis, suggesting that they easily pass through the blood-brain and blood-testis barriers. In parallel embryo development after exposure to nanoparticles should be comparatively investigated. The majority of studies on embryo toxicology have concentrated on piscine embryos, mostly derived from zebrafish. Plants for human food as an important component of the ecosystem need also to be taken into account when evaluating transgenerational effects of engineered nanomaterials in crops. PMID:24683035

Poma, Anna; Colafarina, Sabrina; Fontecchio, Gabriella; Chichiriccò, Giuseppe

2014-01-01

386

Magnetic effects on thermocouples  

NASA Astrophysics Data System (ADS)

Thermometers in laboratory environment and industrial applications are often subject to extraneous, usually unwanted and uncontrolled magnetic fields. Magnetic field influence can be minimized, but cannot be fully cancelled out. Even more, in most cases, there is no awareness of the existence of magnetic fields, let alone their effect on measurement instrumentation. In the past, sensitivity to high dc magnetic fields has been investigated in cryogenics and at high temperatures. More recently, the magnetic effect on weak dc magnetic fields was presented. The goal of this paper was to analyse and empirically and experimentally prove the magnetic sensitivity of thermocouples exposed to low magnetic fields: both dc and ac. Precision and uniform alternating and direct magnetic flux densities were generated by means of permanent magnets and power amplifiers with air-cored coils. The magnetic effect on ferromagnetic and non-ferromagnetic thermocouples at liquid-nitrogen-boiling point (-196 °C), ice point (0 °C), in water (17 °C) and at melting point of gallium fixed point cell (29.7646 °C) was investigated. Magnetic-field-dependent temperature errors of up to 700 mK (at 5.3 mT: dc) and up to 1 °C (at 10 mT: ac 50 Hz magnetic fields) were detected. From the results, it can be concluded that, ideally for temperature measurements of the highest accuracy in the above-cryogenic temperature range, magnetic sensitivity should be estimated and taken into account either as the correction of an error and/or as an additional source of measurement uncertainty. Special consideration should be given to thermocouple orientation relative to the magnetic field direction, influence of metal enclosures and magnetization effects on ferromagnetic components of thermocouples.

Beguš, Samo; Bojkovski, Jovan; Drnovšek, Janko; Geršak, Gregor

2014-03-01

387

Neuroprotective effects of creatine  

Microsoft Academic Search

There is a substantial body of literature, which has demonstrated that creatine has neuroprotective effects both in vitro\\u000a and in vivo. Creatine can protect against excitotoxicity as well as against ?-amyloid toxicity in vitro. We carried out studies\\u000a examining the efficacy of creatine as a neuroprotective agent in vivo. We demonstrated that creatine can protect against excitotoxic\\u000a lesions produced by

M. Flint Beal

2011-01-01

388

Hall Effect Measurements  

NSDL National Science Digital Library

The objective of this Web site is twofold: (1) to describe the Hall measurement technique for determining the carrier density and mobility in semiconductor materials and (2) to initiate an electronic interaction forum where workers interested in the Hall effect can exchange ideas and information. It includes an introductory description of the Hall measurement technique and covers basic principles, equipment, and recommended procedures. Keywords: Conductance, conductivity, resistance, resistivity

2012-07-26

389

Adipokine Effects on Bone  

Microsoft Academic Search

The adipocyte is an important source of factors that act as circulating regulators of bone metabolism. These include estrogens,\\u000a and the adipokines, leptin, resistin, adiponectin, and probably others. Leptin acts directly on bone cells, and in some experimental\\u000a models these effects are modified by its actions on the central nervous system, which impact on appetite, body weight, and\\u000a insulin sensitivity.

Ian R. Reid; J. B. Richards

2009-01-01

390

Treatment Side Effects  

Microsoft Academic Search

Mothers of children referred for psychological services at a community-based, outpatient psychiatric facility completed an assessment of side effects following termination of treatment. The children and their families were randomly assigned to therapists and treatment model (i.e., behavioral or strategic family therapy). A research assistant blind to treatment assignment contacted the mothers following termination and conducted an in-home interview to

Thomas V. Sayger; Steven A. Szykula; Curtis Sudweeks

1992-01-01

391

The Effects of Outliers  

NSDL National Science Digital Library

Created by Illuminations: Resources for Teaching Mathematics, this lesson is designed to help students understand the significance of outliers. This lesson includes thought questions and an applet to help students visualize the effect of an outlier. The authors divide the lesson into different groups, they include: learning objectives, materials, instructional plans, NCTM standards/expectations, and finally references. This is a great interactive resource for those wanting to learn more about correlation and regression.

2009-01-01

392

Lightning effects on aircraft  

NASA Technical Reports Server (NTRS)

Direct and indirect effects of lightning on aircraft were examined in relation to aircraft design. Specific trends in design leading to more frequent lightning strikes were individually investigated. These trends included the increasing use of miniaturized, solid state components in aircraft electronics and electric power systems. A second trend studied was the increasing use of reinforced plastics and other nonconducting materials in place of aluminum skins, a practice that reduces the electromagnetic shielding furnished by a conductive skin.

1977-01-01

393

Effects on Development  

Microsoft Academic Search

This chapter will review the effects produced on neural development by maternal consumption of cannabinoids during gestation\\u000a and lactation, with emphasis in thematuration of several neurotransmitter systems (dopamine, serotonin, opioids, cannabinoids,\\u000a etc.) and possible modifications in their functional expression at the behavioral or neuroendocrine levels. In addition, we\\u000a have analyzed the possible existence of a sexual dimorphism in these ontogenic

J. A. Ramos; M. Gómez; R. de Miguel

394

Quantum Effects In Cosmology  

E-print Network

Contents: Introduction. The Present State of the Universe. What Can We Expect From a Complete Cosmological Theory? An Overview of Quantum Effects in Cosmology. Parametric (Superadiabatic) Amplification of Classical Waves. Graviton Creation in the Inflationary Universe. Quantum States of a Harmonic Oscillator. Squeezed Quantum States of Relic Gravitons and Primordial Density Perturbations. Quantum Cosmology, Minisuperspace Models and Inflation. From the Space of Classical Solutions to the Space of Wave Functions. On the Probability of Quantum Tunneling From "Nothing". Duration of Inflation

L. P. Grishchuk

1993-02-26

395

Power electronics' polluting effects  

Microsoft Academic Search

In use far and wide for improved delivery and control of the electricity supply, power electronics systems are both the cause and remedy of the power system harmonic pollution problem. Here, the authors describe how an insidious side-effect of any solution involving power electronics converters is their generation of high-frequency pollution-namely, conducted and radiated noise in the 100 kHz to

R. Redl; P. Tenti; J. Daan van Wyk

1997-01-01

396

Toward Effective Conversational Messaging  

Microsoft Academic Search

The ubiquity of the telephone suggests it as an ideal messaging tool. The slow, serialoutput of speech, however, makes it difficult to find important messages quickly.MailCall, a telephone-based messaging system using speech recognition, takes a steptoward effective conversational messaging with a combination of filtering, randomaccess, and recognition error handling. Incoming voice and text messages are categorizedand prioritized based on the

Matthew Talin Marx

1995-01-01

397

Preattentive auditory context effects  

Microsoft Academic Search

The effects of auditory context on the preattentive and perceptual organization of tone sequences were investigated. Two sets\\u000a of experiments were conducted in which the pitch of contextual tones was varied, bringing about two different contextual manipulations.\\u000a Preattentive auditory organization was indexed by the mismatch negativity event-related potential, which is elicited by violations\\u000a of auditory regularities even when participants ignore

István Winkler; Elyse Sussman; Mari Tervaniemi; János Horváth; Walter Ritter; Risto Näätänen

2003-01-01

398

The Kaye effect  

NASA Astrophysics Data System (ADS)

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, The Kaye effect, as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid is poured onto a surface. Suddenly, a jet leaves the heap that is formed by the shampoo and begins to 'dance' around the primary jet like a lasso. The phenomenon ends when the 'dancing' jet hits the primary jet and subsequently collapses. We started our investigations based on available literature (Kaye 1963 Nature 197 1001, Versluis et al 2006 J. Stat. Mech., Collyer and Fischer 1976 Nature 261 682). We made experiments with a similar experimental set-up in which we could determine the velocities of both shampoo streams as well as the angle of the 'dancing' stream. From there on, we developed a theoretical model for the energy loss of the jet in the heap. We discovered that the air layer between the jet and the heap is a necessity for the Kaye effect to occur. At this point, our observations differ from the aforementioned literature. This also accounts for the shampoo beam acting as a light guide. Further experiments concerning the viscoelasticity of the shampoo revealed that the elastic property of the shampoo is necessary for the effect to occur. This article is a written version of the oral contribution of the German team to the 21st IYPT competition, which was awarded first prize by an international jury. The article has been edited by European Journal of Physics.

Binder, J. M.; Landig, A. J.

2009-11-01

399

Writing Effective TAFs  

NSDL National Science Digital Library

This module provides an overview of some of the applicable TAF Amendment and Conditional Group usage rules, as presented in the latest version of the National Weather Service Instruction 10-813 on TAF directives. It also presents a methodology for TAF writing and development that will lead to an effective and user-friendly product. The focus is on the ceiling and visibility aspects of the TAF. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Comet

2003-06-28

400

SAD effects on grantmanship  

E-print Network

Seasonal affective disorder (SAD) is a state of depression induced by a lack of sufficient sunlight that occurs at high latitudes during the fall and winter. One effect of SAD is that causes people to be more risk-adverse, an effect that should be considered by granting agencies of high latitude countries. Funding agencies often have programmes aimed at high-risk, innovative research. However, the time of the year during which these purposefully high-risk proposals are evaluated usually does not take into consideration the effects of SAD. In high-latitude countries (e.g., Canada, UK, Nordic and Baltic countries), evaluating proposals for high-risk programmes during the late fall might significantly detract from the very purpose of such programmes. At this time of the year, grant evaluators might be in a darkness-induced state of mild depression. As such, evaluators might be more likely to opt for safe investments, more of the same, the well established, which is the antithesis of innovative research.

Lozano, George A

2014-01-01

401

Ejs Doppler Effect Model  

NSDL National Science Digital Library

The Ejs Doppler Effect model displays the detection of sound waves from a moving source and the change in frequency of the detected wave via the Doppler effect. In addition to the wave fronts from the source a graph depicting the time of emission and time of detection of each of the wave fronts is given. The speed of sound, the velocity of the source and the position and velocity of the detector can be changed via text boxes. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Doppler Effect model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_doppler.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-20

402

Photoelectric Effect Model  

NSDL National Science Digital Library

The EJS Photoelectric Effect model simulates the Photoelectric effect discovered by Hertz in 1887 and described theoretically by Einstein in 1905. Light of a given frequency (energy) shines on a metal in a vacuum tube. If the energy of the photons is greater than the work function of the metal, W, electrons are ejected and can form a current in an external circuit. These photoelectrons will have a kinetic energy if the energy of the light is greater than the work function. If subjected to an electric potential between the plates in the tube, the electrons excited from the metal will be accelerated resulting in an increase, decrease, or stopping of the current. This model provides controls for the frequency of the light source and the external potential on the electron tube. An ammeter allows users to take data for the photo-current. The EJS Photoelectric Effect model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_qm_photoelectric.jar file will run the program if Java is installed.

Palop, Jose I.

2010-07-16

403

Cascading Effects Following Intervention  

PubMed Central

Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial (RCT) of a preventive intervention using Parent Management Training – Oregon Model (PMTO™). The social interaction learning (SIL) model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments. PMID:20883592

Patterson, Gerald R.; Forgatch, Marion S.; DeGarmo, David S.

2010-01-01

404

Effectiveness Review Overview Theresa Triplett  

E-print Network

National Laboratory Office of Contractor Assurance #12;2 Objectives Discuss: ­ What is an Effectiveness Review ­ How to perform an Effectiveness Review #12;3 What is an Effectiveness Review A validation · and prevents recurrence of similar, future events / findings #12;4 What is an Effectiveness Review Key Points

405

SOLAR EFFECTS ON BUILDING DESIGN.  

ERIC Educational Resources Information Center

A REPORT OF A PROGRAM HELD AS PART OF THE BUILDING RESEARCH INSTITUTE 1962 SPRING CONFERENCE ON THE SOLAR EFFECTS ON BUILDING DESIGN. TOPICS DISCUSSED ARE--(1) SOLAR ENERGY DATA APPLICABLE TO BUILDING DESIGN, (2) THERMAL EFFECTS OF SOLAR RADIATION ON MAN, (3) SOLAR EFFECTS ON ARCHITECTURE, (4) SOLAR EFFECTS ON BUILDING COSTS, (5) SELECTION OF…

Building Research Inst., Inc., Washington, DC.

406

Pairing correlations and effective mass  

SciTech Connect

We study the effect of effective mass on pairing correlations in the ground states of superfluid nuclei {sup 124}Sn and {sup 136}Sn. Various parameter sets of Skyrme interactions and relativistic Lagrangians are adopted to study pairing correlations across a wide range of effective mass. It is shown that surface-type pairing interaction gives an almost constant pairing gap as a function of the effective mass, while volume-type pairing interaction shows rather strong dependence of the pairing gap upon the effective mass. The local pair potentials of various effective interactions are also examined in relation to the effective mass.

Yoshida, Satoshi [Science Research Center, Hosei University, 2-17-1 Fujimi, Chiyoda, Tokyo 102-8160 (Japan); Sagawa, Hiroyuki [Center for Mathematical Sciences, University of Aizu Aizu-Wakamatsu, Fukushima 965-8580 (Japan)

2008-05-15

407

Quantum Effects in Biology  

NASA Astrophysics Data System (ADS)

List of contributors; Preface; Part I. Introduction: 1. Quantum biology: introduction Graham R. Fleming and Gregory D. Scholes; 2. Open quantum system approaches to biological systems Alireza Shabani, Masoud Mohseni, Seogjoo Jang, Akihito Ishizaki, Martin Plenio, Patrick Rebentrost, Alàn Aspuru-Guzik, Jianshu Cao, Seth Lloyd and Robert Silbey; 3. Generalized Förster resonance energy transfer Seogjoo Jang, Hoda Hossein-Nejad and Gregory D. Scholes; 4. Multidimensional electronic spectroscopy Tomáš Man?al; Part II. Quantum Effects in Bacterial Photosynthetic Energy Transfer: 5. Structure, function, and quantum dynamics of pigment protein complexes Ioan Kosztin and Klaus Schulten; 6. Direct observation of quantum coherence Gregory S. Engel; 7. Environment-assisted quantum transport Masoud Mohseni, Alàn Aspuru-Guzik, Patrick Rebentrost, Alireza Shabani, Seth Lloyd, Susana F. Huelga and Martin B. Plenio; Part III. Quantum Effects in Higher Organisms and Applications: 8. Excitation energy transfer in higher plants Elisabet Romero, Vladimir I. Novoderezhkin and Rienk van Grondelle; 9. Electron transfer in proteins Spiros S. Skourtis; 10. A chemical compass for bird navigation Ilia A. Solov'yov, Thorsten Ritz, Klaus Schulten and Peter J. Hore; 11. Quantum biology of retinal Klaus Schulten and Shigehiko Hayashi; 12. Quantum vibrational effects on sense of smell A. M. Stoneham, L. Turin, J. C. Brookes and A. P. Horsfield; 13. A perspective on possible manifestations of entanglement in biological systems Hans J. Briegel and Sandu Popescu; 14. Design and applications of bio-inspired quantum materials Mohan Sarovar, Dörthe M. Eisele and K. Birgitta Whaley; 15. Coherent excitons in carbon nanotubes Leonas Valkunas and Darius Abramavicius; Glossary; References; Index.

Mohseni, Masoud; Omar, Yasser; Engel, Gregory S.; Plenio, Martin B.

2014-08-01

408

'The Kesterson effect'  

USGS Publications Warehouse

Hypothesized to be derived from Cretaceous marine sedimentary rocks, selenium contamination of the Kesterson National Wildlife Refuge is traced through irrigation drainage to the source bedrock of the California Coast Ranges. This biogeochemical pathway of selenium is defined here as the 'Kesterson effect.' At the refuge ponds, this effect culminated in 1983 in a 64% rate of deformity and death of embryos and hatchlings of wild aquatic birds. From the previous companion paper on irrigation drainage, the Kesterson effect has been implicated in nine of 11 reconnaissance areas studied in the western United States. Deformities have resulted in at least five of these sites. Climatic, geologic, hydrologic, and soil conditions in these reconnaissance areas are similar to those in the area surrounding Kesterson National Wildlife Refuge in the west-central San Joaquin Valley of California, in California, selenium as selenate, was ultimately found weathered with sulfur from marine sources in soluble sodium and magnesium sulfate salts, which are concentrated by evaporation on farmland soils. The Se, mobilized by irrigation drainage, is bioaccumulated to toxic levels in refuge wetland ponds that are located mainly in hydrologically closed basins and thus act as concentrating disposal points. The depositional environment of the ponds may be similar to that of the nutrient-rich continental shelf edge and slope in which Cretaceous, Eocene, and Miocene sediments found to be seleniferous in the California Coast Ranges were deposited. Bioaccumulation may be therefore a primary mechanism of selenium enrichment in ancient sediments in addition to that of the formerly suggested Cretaceous volcanic pathway.

Presser, T.S.

1994-01-01

409

Transistors: The Field Effect  

NSDL National Science Digital Library

Transistors are the building blocks of modern electronic devices. Your cell phones, iPods, and computers all depend on them to operate. Thanks to today's microfabrication technology, transistors can be made very tiny and be massively produced. You are probably using billions of them while working with this activity now--as of 2006, a dual-core Intel microprocessor contains 1.7 billion transistors. The field effect transistor is the most common type of transistor. So we will focus on it in this activity.

Consortium, The C.

2011-12-11

410

Hepatoprotective effects of mushrooms.  

PubMed

The particular characteristics of growth and development of mushrooms in nature result in the accumulation of a variety of secondary metabolites such as phenolic compounds, terpenes and steroids and essential cell wall components such as polysaccharides, b-glucans and proteins, several of them with biological activities. The present article outlines and discusses the available information about the protective effects of mushroom extracts against liver damage induced by exogenous compounds. Among mushrooms, Ganoderma lucidum is indubitably the most widely studied species. In this review, however, emphasis was given to studies using other mushrooms, especially those presenting efforts of attributing hepatoprotective activities to specific chemical components usually present in the mushroom extracts. PMID:23884116

Soares, Andréia Assunço; de Sá-Nakanishi, Anacharis Babeto; Bracht, Adelar; da Costa, Sandra Maria Gomes; Koehnlein, Eloá Angélica; de Souza, Cristina Giatti Marques; Peralta, Rosane Marina

2013-01-01

411

Effective string theory simplified  

NASA Astrophysics Data System (ADS)

In this note we simplify the formulation of the Poincaré-invariant effective string theory in D dimensions by adding an intrinsic metric and embedding its dynamics into the Polyakov formalism. We use this formalism to classify operators order-by-order in the inverse physical length of the string, in a fully gauge-invariant framework. We then use this classification to analyze the universality and nonuniversality of observables, up to and including the second sub-leading order in the long string expansion.

Hellerman, Simeon; Maeda, Shunsuke; Maltz, Jonathan; Swanson, Ian

2014-09-01

412

Isotopic trans effect  

SciTech Connect

D is found to have a higher trans influence than H, as reflected in /sup 1/J(Pt,P) and /sup 1/J(Pt,C) coupling constants in trans-(HPt(PEt/sub 3/)/sub 2/L)/sup +/ (L = /sup 13/CO or PEt/sub 3/) and the PtD analogues. The isotopic effect on trans ligand labilization is also discussed in the case of (IrH/sub 2/(Me/sub 2/CO)/sub 2/(PPh/sub 3/)/sub 2/)/sup +/. Molecular H/sub 2/ (D/sub 2/) complexes are proposed as intermediates in the deuteration of the iridium complex.

Crabtree, R.H.; Habib, A.

1986-09-24

413

Interfacial effects in multilayers  

SciTech Connect

Interfacial structure and the atomic interactions between atoms at interfaces in multilayers or nano-laminates have significant impact on the physical properties of these materials. A technique for the experimental evaluation of interfacial structure and interfacial structure effects is presented and compared to experiment. In this paper the impact of interfacial structure on the performance of x-ray, soft x-ray and extreme ultra-violet multilayer optic structures is emphasized. The paper is concluded with summary of these results and an assessment of their implications relative to multilayer development and the study of buried interfaces in solids in general.

Barbee, T.W., Jr.

1998-04-01

414

Effective Gauge Theory  

NASA Astrophysics Data System (ADS)

The global iso-spin invariance of the hadronic interaction, which is areflection of the SU(2) × U(1) QFD and QCD, as well as the U(1) invariance related to the charge of the hadrons, is formulated as an effective gauge theory. The pseudo-gauge fields in this theory are the vector mesons, and these composite fields become massive when the Higgs field at the quark-lepton level and the bar{q}q pair states acquire the vacuum expectation value. The formulation gives a theoretical basis for the vector dominance model and gives some insights to the possible composite structure of quarks and leptons.

Ebata, T.

1982-02-01

415

TEACHING PHYSICS: Capillary effects  

NASA Astrophysics Data System (ADS)

We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

Ivanov, Dragia; Petrova, Hristina

2000-07-01

416

Assessments of astronaut effectiveness  

NASA Technical Reports Server (NTRS)

This study examined the reliability and convergent validity of three methods of peer and supervisory ratings of the effectiveness of individual NASA astronauts and their relationships with flight assignments. These two techniques were found to be reliable and relatively convergent. Seniority and a peer-rated Performance and Competence factor proved to be most closely associated with flight assignments, while supervisor ratings and a peer-rated Group Living and Personality factor were found to be unrelated. Results have implications for the selection and training of astronauts.

Rose, Robert M.; Helmreich, Robert L.; Fogg, Louis; Mcfadden, Terry J.

1993-01-01

417

75 FR 10411 - Borrower Rights; Effective Interest Rates; Effective Date  

Federal Register 2010, 2011, 2012, 2013

...Part 617 RIN 3052-AC45 Borrower Rights; Effective Interest Rates; Effective Date AGENCY: Farm Credit Administration...publicized external index receive appropriate disclosure of interest rate changes in accordance with statutory requirements...

2010-03-08

418

Ecotoxicological effects extrapolation models  

SciTech Connect

One of the central problems of ecological risk assessment is modeling the relationship between test endpoints (numerical summaries of the results of toxicity tests) and assessment endpoints (formal expressions of the properties of the environment that are to be protected). For example, one may wish to estimate the reduction in species richness of fishes in a stream reach exposed to an effluent and have only a fathead minnow 96 hr LC50 as an effects metric. The problem is to extrapolate from what is known (the fathead minnow LC50) to what matters to the decision maker, the loss of fish species. Models used for this purpose may be termed Effects Extrapolation Models (EEMs) or Activity-Activity Relationships (AARs), by analogy to Structure-Activity Relationships (SARs). These models have been previously reviewed in Ch. 7 and 9 of and by an OECD workshop. This paper updates those reviews and attempts to further clarify the issues involved in the development and use of EEMs. Although there is some overlap, this paper does not repeat those reviews and the reader is referred to the previous reviews for a more complete historical perspective, and for treatment of additional extrapolation issues.

Suter, G.W. II

1996-09-01

419

Predicting Earthquake Effects  

NASA Astrophysics Data System (ADS)

Advances in the earth sciences and information technology have lead to dramatic improvements in our ability to respond to, as well as anticipate and mitigate, earthquake effects in our communities. The development of Geographic Information System (GIS) based tools such as ShakeMap and HAZUS have ushered in a new era of risk and emergency management. Real-time maps of strong ground motion, coupled with engineering-based descriptions of building and infrastructure inventory and vulnerability enable more accurate determinations of the location and severity of earthquake damage and the socio-economic consequences for emergency managers and officials following significant earthquakes. The ability to map the distribution and growth of seismic risk in the United States has long-term benefits for public policy as well. Long-term forecasts of seismic risk based on varying mitigation strategies can provide guidance for developing national and local earthquake policy. The successful performance of the Trans-Alaska pipeline during the 2002 Denali earthquake illustrates the dependence of performance-based engineering on the ability to predict earthquake effects (e.g., levels of strong ground motion, amounts of fault displacement or ground deformation). Being able to reduce the uncertainty in predicting these parameters has significant economic consequences and enables decision makers to more efficiently prioritize risk management strategies.

Nishenko, S.

2005-12-01

420

Lake Effect Clouds  

NASA Technical Reports Server (NTRS)

The lake effect is particularly clear in this Sea-viewing Wide field-of-view Sensor (SeaWiFS) true-color image of the North American Great Lakes region, acquired December 5, 2000. Lakes Nipigon, Superior, and Michigan show striking contrasts between clear and cloudy air as the wind blows from the northwest across the lakes. As it flows across the relatively warm lakes, the cold dry air gathers heat and moisture from the surface. The warm moist air rises into the atmosphere and mixes vigorously with the cold dry air above. The layer of warm moist air deepens as it travels across the lake. Some of the evaporated water from the lake condenses into streamers of fog rising from the surface, while much of the moisture condenses to form a stratocumulus cloud in the upper half of the mixed layer. The cloud-forming water droplets may freeze into ice crystals and, due to accumulated water deposition over time, grow into snowflakes. This process can generate snowstorms that produce significant amounts of snowfall downwind. It is not uncommon for lake effect snowstorms to produce as much as two feet of snow within a 24-hour period in northwestern parts of New York and Pennsylvania. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

2002-01-01

421

Astroinfect Effect - Revised Model  

NASA Astrophysics Data System (ADS)

Space activities lead to a lasting pollution of the Solar System. Light pressure, gravitational interaction with the planets, collisions and explosions (similar to spontaneous explosions of Earth satellite) of artefacts in the outer parts of the planetary system can lead to effective, inevitable spontaneous leakage of interplanetary trash into the interstellar medium, even in the absence of interstellar flights. If there are alien artefacts between the stars, some of them are likely to fall down to Earth at times [1,2]. They could be non-sterile, so sporadic interstellar panspermia is possible [3]. The minimum pollution threshold for such panspermia was estimated [2] for 2 m-microartefacts at the level of Galactic cosmic radiation of 4 x 10-7 rad/s [4]. However, C. Mileikowsky showed that, if the X-rays are taken into consideration, the interstellar dose rate is ~3 x 10- 5 rad/s [5]. At this high dose rate the microartefacts must be sterilised at the distances >0.1 pc from the planetary system, hence they cannot be an effective agent of interstellar panspermia. Sufficient protection of microbial spores is possible inside macroartefacts. Therefore, the panspermia model and the corresponding minimum pollution threshold must be re-examined.

Arkhipov, A. V.

422

Topological phase effects  

E-print Network

Quantum eigenstates undergoing cyclic changes acquire a phase factor of geometric origin. This phase, known as the Berry phase, or the geometric phase, has found applications in a wide range of disciplines throughout physics, including atomic and molecular physics, condensed matter physics, optics, and classical dynamics. In this article, the basic theory of the geometric phase is presented along with a number of representative applications. The article begins with an account of the geometric phase for cyclic adiabatic evolutions. An elementary derivation is given along with a worked example for two-state systems. The implications of time-reversal are explained, as is the fundamental connection between the geometric phase and energy level degeneracies. We also discuss methods of experimental observation. A brief account is given of geometric magnetism; this is a Lorenz-like force of geometric origin which appears in the dynamics of slow systems coupled to fast ones. A number of theoretical developments of the geometric phase are presented. These include an informal discussion of fibre bundles, and generalizations of the geometric phase to degenerate eigenstates (the nonabelian case) and to nonadiabatic evolution. There follows an account of applications. Manifestations in classical physics include the Hannay angle and kinematic geometric phases. Applications in optics concern polarization dynamics, including the theory and observation of Pancharatnam's phase. Applications in molecular physics include the molecular Aharonov-Bohm effect and nuclear magnetic resonance studies. In condensed matter physics, we discuss the role of the geometric phase in the theory of the quantum Hall effect.

J. M. Robbins

2010-08-31

423

The thermoelectric properties of bulk crystalline n- and p-type Mg2Si prepared by the vertical Bridgman method  

NASA Astrophysics Data System (ADS)

Bulk Mg2Si crystals were grown using the vertical Bridgman melt growth method. The n-type and p-type dopants, bismuth (Bi) and silver (Ag), respectively, were incorporated during the growth. X-ray powder diffraction analysis revealed clear peaks of Mg2Si with no peaks associated with the metallic Mg and Si phases. Residual impurities and process induced contaminants were investigated by using glow discharge mass spectrometry (GDMS). A comparison between the results of GDMS and Hall effect measurements indicated that electrical activation of the Bi doping in the Mg2Si was sufficient, while activation of the Ag doping was relatively smaller. It was shown that an undoped n-type specimen contained a certain amount of aluminum (Al), which was due either to residual impurities in the Mg source or the incorporation of process-induced impurities. Thermoelectric properties such as the Seebeck coefficient and the electrical and thermal conductivities were measured as a function of temperature up to 850 K. The dimensionless figures of merit for Bi-doped and Ag-doped samples were 0.65 at 840 K and 0.1 at 566 K, respectively. Temperature dependence of the observed Seebeck coefficient was fitted well by the two-carrier model. The first-principles calculations were carried out by using the all-electron band-structure calculation package (ABCAP) in which the full-potential linearized augmented-plane-wave method was employed. The ABCAP calculation adequately presents characteristics of the Seebeck coefficients for the undoped and heavily Bi-doped samples over the whole measured temperature range from room temperature to 850 K. The agreement between the theory and the experiment is poorer for the Ag-doped p-type samples.

Akasaka, Masayasu; Iida, Tsutomu; Matsumoto, Atsunobu; Yamanaka, Kohei; Takanashi, Yoshifumi; Imai, Tomohiro; Hamada, Noriaki

2008-07-01

424

Key to effective video retrieval: effective cataloging and browsing  

Microsoft Academic Search

-—— ——— — : 1. ABSTRACT Mukirnedia data is an increasingly important information medium today. Providing intelligent access for effective use of this information continues to offer challenges in digital Iibrary research. As computer vision, image processing and speech recognition research continue to progress, we examine the effectiveness of these fully automated techniques in architecting effective video retrieval systems. We

Dulce B. Ponceleon; Savitha Srinivasan; Arnon Amir; Dragutin Petkovic; Dan Diklic

1998-01-01

425

Magnetoelectric effects in multiferroics  

NASA Astrophysics Data System (ADS)

Magneto-electric phenomena were investigated in two different multiferroic systems: The strong coupling of dielectric and magnetic properties and the simultaneous occurrence of long-range magnetic and ferroelectric order are discussed for rare earth manganites and sulfo spinels. A phase diagram of Eu1-xYxMnO3 is established, which recovers the main features of the well-known magneto-electric phase diagram for the pure rare earth manganites RMnO3. Here a variety of magnetic and electric phases emerge with varying rare earth ions R. As function of temperature and external magnetic field, also Y doped EuMnO3 compounds undergo a sequence of different magnetic and polar phase transitions for varying effective ionic radii of the rare earth ions. Special attention is paid to the occurrence of fundamentally new hybrid spin-electromagnetic excitations, which we name electromagnons and are characterized as spin waves that can be excited by an ac electric field. These excitations are identified in Eu1-xYxMnO3 with x = 0.2, in GdMnO3, and in TbMnO3. Specifically in GdMnO3 the electromagnons can easily be suppressed by external magnetic fields and allow tuning the index of refraction by moderate fields. In the second part we discuss the simultaneous appearance of colossal magneto-resistance (CMR) and colossal magneto-capacitance (CMC) effects in chromium sulfo spinels. In CdCr2S4 ferromagnetism of localized Cr spins evolves at 85 K, while polar order is established below 130 K. The onset of ferroelectric order is neither accompanied by the occurrence of soft modes nor by structural changes which break the inversion symmetry of the high-temperature cubic phase. HgCr2S4 becomes ferroelectric close to 70 K while a complex antiferromagnetic order is found below 25 K. CMR and CMC effects are specifically strong in the mercury compound, as moderate magnetic fields of only 0.1 T induce ferromagnetism at much higher temperatures. We speculate that the occurrence of ferroelectricity in these multiferroic compounds is rather of electronic than of ionic origin.

Loidl, Alois

2006-03-01

426

Local spin currents in magnetothermal landscapes  

NASA Astrophysics Data System (ADS)

Spin caloritronic effects - such as the spin Seebeck effect - are concerned with the interplay of heat and spin currents and have been experimentally studied using homogeneous thermal gradients to date. However, in order to understand the underlying magnon-phonon interactions that take place on short length scales, a spatially resolved study of spin currents in magnetothermal landscapes [1] is mandatory. We here use a focussed, scannable laser beam to generate local thermal perturbations in thin film multilayers incorporating the ferromagnetic insulator Y3Fe5O12 (YIG). In both, YIG/Pt thin film bilayers and YIG/Au/Pt trilayers, the laser heating results in a difference of the magnon and electron temperatures in the YIG and Pt, respectively, as quantitatively modeled in numerical simulations. In the presence of this temperature difference, we experimentally observe a local in-plane electric field in the YIG/Pt and YIG/Au/Pt samples. This electric field is ascribed to the detection of the local longitudinal spin Seebeck effect via the inverse spin Hall effect in Pt. Our experiments allow to, e.g., electrically image magnetic texture in a magnetic insulator and provide a local, bipolar, magnetically controllable spin current source. [1] M. Weiler et al. PRL 108, 106602

Weiler, M.; Schreier, M.; Huebl, H.; Althammer, M.; Opel, M.; Gross, R.; Goennenwein, S. T. B.

2013-03-01

427

Managing Chemotherapy Side Effects: Pain  

MedlinePLUS

... services national institutes of health Managing Chemotherapy Side Effects Pain “I was worried about getting addicted to ... to pay for pain medicine. Managing Chemotherapy Side Effects: Pain Keep track of the pain. Each day, ...

428

Hall Effect in a Plasma.  

ERIC Educational Resources Information Center

Describes an apparatus and procedure for conducting an undergraduate laboratory experiment to quantitatively study the Hall effect in a plasma. Includes background information on the Hall effect and rationale for conducting the experiment. (JN)

Kunkel, W. B.

1981-01-01

429

Atomistic and orthoatomistic effect algebras  

SciTech Connect

We characterize atomistic effect algebras, prove that a weakly orthocomplete Archimedean atomic effect algebra is orthoatomistic and present an example of an orthoatomistic orthomodular poset that is not weakly orthocomplete.

Tkadlec, Josef [Department of Mathematics, Faculty of Electrical Engineering, Czech Technical University, 166 27 Praha (Czech Republic)

2008-05-15

430

Atomistic and orthoatomistic effect algebras  

E-print Network

We characterize atomistic effect algebras, prove that a weakly orthocomplete Archimedean atomic effect algebra is orthoatomistic and present an example of an orthoatomistic orthomodular poset that is not weakly orthocomplete.

Josef Tkadlec

2007-12-21

431

Flight effects of fan noise  

NASA Technical Reports Server (NTRS)

Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

Chestnutt, D. (editor)

1982-01-01

432

HIV Medicines and Side Effects  

MedlinePLUS

... will depend on a person’s individual needs. Can HIV medicines cause side effects? HIV medicines help people ... What are common short-term side effects from HIV medicines? When starting an HIV medicine for the ...

433

Heat Island Effect  

NSDL National Science Digital Library

For people living in and around cities, heat islands are of growing concern. This phenomenon describes urban and suburban temperatures that are 2 to 10 degrees F (1 to 6 degrees C) hotter than nearby rural areas. Elevated temperatures can impact communities by increasing peak energy demand, air conditioning costs, air pollution levels, and heat-related illness and mortality. The materials available here describe the basic causes of the heat island effect, and what can be done to mitigate some of the impacts. There is also an overview of the Urban Heat Island Pilot Project (UHIPP), an initiative being conducted in five cities in the U.S. to adopt and evaluate heat island reduction strategies and programs.

434

[Side effects of caffeine].  

PubMed

Caffeine is one of the most commonly ingested alkaloids worldwide. It is present in coffee, tea, soft and energy drinks, chocolate, etc. Currently published data has been stressed that the metyloxantine consumption increases the risk of coronary heart disease, arterial hypertension, arterial stiffness, and an elevation of cholesterol and homocysteine plasma concentration. The acute high consumption may also modulate insulin sensitivity and glucose blood level. However, the long-term consumption reduces the incidence of the type 2 diabetes mellitus. When administered in high doses the substance may cause various side effects, related to abnormal stimulation of the central nervous system, decrease tonus of the lower esophageal sphincter, as well as increase risk of miscarriage and intrauterine growth retardation. The final manifestation of side reactions is dependent on the genotype, especially polymorphisms of genes associated with caffeine metabolism, i.e., cytochrome P450-CYP1A2 and catechol-O-methyltransferase (COMT). PMID:19999796

Dworza?ski, Wojciech; Opielak, Grzegorz; Burdan, Franciszek

2009-11-01

435

The Greenhouse Effect  

NSDL National Science Digital Library

This site is a joint effort of NOAA Research and the College of Education at the University of South Alabama. The goal of the site is to provide middle school science students and teachers with research and investigation experiences using on-line resources. In this unit students learn about what the greenhouse effect is and what causes it. By looking at greenhouse gas rates and amounts, students can propose reasons for trends and solutions to global warming. Parts of the unit include gathering information from other websites, applying the data gathered, and performing enrichment exercises. This site contains a downloadable teachers guide, student guide, and all activity sheets to make the unit complete.

436

Orbital magnetic ratchet effect  

NASA Astrophysics Data System (ADS)

Magnetic ratchets—two-dimensional systems with superimposed noncentrosymmetric ferromagnetic gratings—are considered theoretically. It is demonstrated that excitation by radiation results in a directed motion of two-dimensional carriers due to the pure orbital effect of the periodic magnetic field. Magnetic ratchets based on various two-dimensional systems such as topological insulators, graphene, and semiconductor heterostructures are investigated. The mechanisms of the electric current generation caused by both radiation-induced heating of carriers and by acceleration in the radiation electric field in the presence of a space-oscillating Lorentz force are studied in detail. The electric currents sensitive to the linear polarization plane orientation as well as to the radiation helicity are calculated. It is demonstrated that the frequency dependence of the magnetic ratchet currents is determined by the dominant elastic-scattering mechanism of two-dimensional carriers and differs for the systems with linear and parabolic energy dispersions.

Budkin, G. V.; Golub, L. E.

2014-09-01

437

The hot chocolate effect  

NASA Astrophysics Data System (ADS)

The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

Crawford, Frank S.

1982-05-01

438

Grantmakers for Effective Organizations  

NSDL National Science Digital Library

Grantmakers for Effective Organizations (GEO) makes it their mission to promote the strategies and practices that contribute to grantee success. To this end, the GEO website contains information about its outreach efforts, peer learning opportunities, conferences, and upcoming events. Within GEO Priorities visitors can learn about the organization's own development plan and long-term goals, while the GEO Publications area contains a raft of useful publications for policy types and others. Noteworthy publications, here, include "Many Hands, More Impact: Philanthropy's Role in Supporting Movements" and "Cracking the Network Code: Four Principles for Grantmakers." The Peer Learning Opportunities section is another great installment, containing links to helpful webinars, speaking engagement possibilities, and other useful resources.

439

Effective monitoring of agriculture.  

PubMed

An opinion piece published in Nature proposed a global network for agricultural monitoring [J. Sachs, R. Remans, S. Smukler, L. Winowiecki, S. J. Andelman, K. G. Cassman, D. Castle, R. DeFries, G. Denning, J. Fanzo, L. E. Jackson, R. Leemans, J. Leemans, J. C. Milder, S. Naeem, G. Nziguheba, C. A. Palm, J. P. Reganold, D. D. Richter, S. J. Scherr, J. Sircely, C. Sullivan, T. P. Tomich and P. A. Sanchez, Nature, 2010, 466, 558-560.]. Whilst we agree with Sachs et al. that monitoring of agricultural systems is a critically important activity of global significance, especially given increasing problems with global food security and the potential impacts of agriculture on the environment [J. Cribb, The Coming Famine. The Global Food Crisis and What We Can Do to Avoid It, CSIRO Publishing and University of California Press, Melbourne and Oakland, 2010.], we argue in this paper that their generic, mandated monitoring framework has a high probability of failure or at best will be highly inefficient. We base this conclusion on our recently published examination of the factors influencing the success or failure of monitoring programs worldwide [D. B. Lindenmayer and G. E. Likens, Effective Ecological Monitoring, CSIRO Publishing and Earthscan, Melbourne and London, 2010.]. We briefly outline what we believe are three serious flaws in the monitoring framework proposed by Sachs et al. We then suggest an alternative approach that we argue would be more effective, more efficient, and have a greater chance of successfully addressing key issues in sustainable agriculture. PMID:21479312

Lindenmayer, David B; Likens, Gene E

2011-06-01

440

The rugosity effect Dorin Bucur  

E-print Network

The rugosity effect Dorin Bucur Abstract This paper surveys the series of lectures given-Murat, Babuska's paradox, the Courant-Hilbert example and the rugosity effect in fluid dynamics. Some classical conditions are presented. In particular we describe different ways to deal with the rugosity effect in fluid

Bucur, Dorin

441

Probiotics: mechanisms and established effects  

Microsoft Academic Search

The definition for probiotics has gradually changed with increasing understanding of the mechanisms by which they influence human health. Health effects related to changes in the intestinal microflora also accompany or are related to adhesion and immune system effects, competitive exclusion or metabolic and nutritional effects, with an increasing array of other potential modes of action. Most clinically documented and

Arthur C. Ouwehand; Pirkka V. Kirjavainen; Colette Shortt; Seppo Salminen

1999-01-01

442

Assessing and Improving Institutional Effectiveness.  

ERIC Educational Resources Information Center

Information to promote assessment of organizational effectiveness in colleges and universities is presented, along with an exercise to rank the effectiveness of 10 institutions. The exercise uses three types of criteria to indicate effectiveness: subjective ratings, data about students and activities, and institutional capacity and financial…

Cameron, Kim S.

443

Numerical calculation of effective action  

NASA Astrophysics Data System (ADS)

We propose a method to calculate the effective action for scalar theories. This is an extension of the constraint effective potential method, so it is easily applied to lattice calculations. We apply this method to lattice Z2 symmetric ?? 4 theory and discuss the effectiveness of this method.

Tominaga, S.

1999-03-01

444

Hall effect in spinor condensates  

SciTech Connect

We consider a neutral spinor condensate moving in a periodic magnetic field. The spatially dependent magnetic field induces an effective spin-dependent Lorentz force, which in turn gives rise to a spin-dependent Hall effect. Simulations of the Gross-Pitaevskii equation quantify the Hall effect. We discuss possible experimental realizations.

Taillefumier, Mathieu; Dahl, Eskil K.; Brataas, Arne [Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Hofstetter, Walter [Institut fuer Theoretische Physik, J. W. Goethe-Universitaet, Max-von-Laue-Strasse 1, 60438 Frankfurt/Main (Germany)

2009-07-01

445

The Enigma of Organizational Effectiveness.  

ERIC Educational Resources Information Center

Organizational effectiveness is not a clearly defined concept. The author illustrates how the four most widely used models are not uniformly applicable. He states the evaluator must make explicit certain critical choices when measuring effectiveness. These criteria reveal the definition of effectiveness and what is being measured. (DWH)

Cameron, Kim

1981-01-01

446

Faculty Perceptions of Institutional Effectiveness  

ERIC Educational Resources Information Center

This study examined (a) the differences in perceptions of faculty, full-time versus part-time, at a community college in northern Alabama on the importance of institutional effectiveness activities; (b) the factors that affect perceptions of the importance of institutional effectiveness activities; and (c) the effect of academic discipline,…

LoCascio, Susan H.

2010-01-01

447

Solar Neutrino Matter Effects Redux  

E-print Network

Following recent low-threshold analysis of the Sudbury Neutrino Observatory and asymmetry measurements of the BOREXINO Collaboration of the solar neutrino flux, we revisit the analysis of the matter effects in the Sun. We show that solar neutrino data constrains the mixing angle $\\theta_{13}$ poorly and that subdominant Standard Model effects can mimic the effects of the physics beyond the Standard Model.

A. B. Balantekin; A. Malkus

2011-09-24

448

Side effects with amiodarone therapy  

Microsoft Academic Search

Amiodarone hydrochloride is increasingly being used in the treatment of ventricular and supraventricular arrhythmias. Although a highly effective anti-arrhythmic agent, its use is restricted by the high incidence of side effects. To elucidate the value of monitoring serum level of both the parent drug and its active metabolite in predicting the occurrence of side effects, the investigators examined 109 patients

R. Shukla; N. I. Jowett; D. R. Thompson; J. E. Pohl

1994-01-01

449

40 CFR 1508.8 - Effects.  

Code of Federal Regulations, 2010 CFR

...ecosystems. Effects and impacts as used in these regulations are synonymous. Effects includes ecological (such as the effects on natural resources...or cumulative. Effects may also include...believes that the effect will be...

2010-07-01

450

Gravitomagnetic effects in conformal gravity  

E-print Network

Gravitomagnetic effects are characterized by two phenomena: first, the geodetic effect which describes the precession of the spin of a gyroscope in a free orbit around a massive object, second, the Lense-Thirring effect which describes the precession of the orbital plane about a rotating source mass. We calculate both these effects in the fourth-order theory of conformal Weyl gravity for the test case of circular orbits. We show that for the geodetic effect a linear term arises which may be interesting for high radial orbits, whereas for the Lense-Thirring effect the additional term has a diminishing effect for most orbits. Circular orbits are also considered in general leading up to a generalization of Kepler's third law.

Said, Jackson Levi; Adami, Kristian Zarb

2014-01-01

451

Gravitomagnetic effects in conformal gravity  

E-print Network

Gravitomagnetic effects are characterized by two phenomena: first, the geodetic effect which describes the precession of the spin of a gyroscope in a free orbit around a massive object, second, the Lense-Thirring effect which describes the precession of the orbital plane about a rotating source mass. We calculate both these effects in the fourth-order theory of conformal Weyl gravity for the test case of circular orbits. We show that for the geodetic effect a linear term arises which may be interesting for high radial orbits, whereas for the Lense-Thirring effect the additional term has a diminishing effect for most orbits. Circular orbits are also considered in general leading up to a generalization of Kepler's third law.

Jackson Levi Said; Joseph Sultana; Kristian Zarb Adami

2014-01-10

452

Public Opinion on Mass Media Effects: Perceived Societal Effects and Perceived Personal Effects.  

ERIC Educational Resources Information Center

The questionnaire in a study of perceived mass media effects included nine statements about the possible negative effects of the mass media, to which respondents could agree, disagree, or indicate "no opinion," and an open-ended question that asked the subjects what effects the mass media had on them personally. Most of the 340 respondents showed…

Tiedge, James T.

453

Low Temperature Electronic and Magnetic Properties of CePd3Mx  

NASA Astrophysics Data System (ADS)

The intermediate valence compound CePd3 is a strong candidate for low temperature thermoelectric applications due to its unusually large Seebeck coefficient which peaks at approximately 115 ?V/K near 125K. This phenomenon results from a sharp peak in the density of states near the Fermi level due to the hybridization of conduction electrons with those in the partially occupied cerium f-shell, thus making the system highly sensitive to changes in the average cerium valence state. We have systematically studied the structural and thermoelectric properties of various CePd3Mx compounds, where M is an s- or p-block element and 0 < x < 0.1, in order to explore the effects of such partial filling on the cerium valence. The results of X-ray diffraction, Seebeck coefficient, and magnetic susceptibility measurements are reported. We have found that incorporating M elements of various valence configurations has similar effects on the electronic and magnetic properties as changing the M concentration, thus establishing an effective new mechanism for tailoring the thermoelectric properties of the system.

Boona, Stephen; Morelli, Donald

2012-02-01

454

Fabrication and properties of thermoelectric oxide thick films deposited with aerosol deposition method  

NASA Astrophysics Data System (ADS)

Thermoelectric materials can directly convert thermal energy to electric energy via Seebeck effect and have attracted attention for clean energy harvesting material. Ca3Co4O9+? (Co349) oxide shows a high thermoelectric performance. Since the Co349 is a misfit-layered oxide, the c-axis oriented structure should be required to achieve high thermoelectric performance. In this study, the Co349 thick film was deposited with aerosol deposition (AD) method. The effect of process parameters on the microstructure and thermoelectric properties were investigated. The thermal strain caused by the difference in thermal expansion coefficient should be less than 0.2%. The deposition rate of 2 ?m/min could be attained by controlling particle size distribution. The c-axis oriented Co349 film was obtained after the annealing at the temperature higher than 700°C. Seebeck coefficient of 170 (?V/°C) and electrical conductivity of 110 (S/cm) were achieved at 700 °C in the film annealed at 900 °C for 1 hour. The thermoelectric performance could be kept up to the thick film of 55?m. These values were as high as those of the usual bulk samples. This suggests that the AD process is effective to fabricate thick film type thermoelectric module.

Nakamura, Y.; Matsufuji, Y.; Inoue, M.

2012-03-01

455

Time-integral type strongly correlated electronic thin-film laser energy meter  

NASA Astrophysics Data System (ADS)

Strongly correlated electronic (SCE) systems, such as high-temperature superconducting (HTSC) cuprate and colossal magnetoresistance (CMR) manganite thin films, exhibit giant laser-induced thermoelectric voltage (LITV) effect due to anisotropic Seebeck effect and have a great potential for laser detector applications. In this work, we develop a novel time-integral type LaSrMnO thin-film laser energy meter based on anisotropic Seebeck effect. An epitaxial LaSrMnO thin film prepared by means of the pulsed laser deposition method onto a vicinal cut LaAlO3 substrate is irradiated by a 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonics at room temperature. The time integral of the LITV signal shows a good linear relationship with the laser energy per pulse in the measured wavelength range, which not only confirms the theoretical analysis, but also provides the basis for designing time-integral type laser energy meter. The advantages over other conventional laser detectors, such as fast (nanosecond order) response, spectrally broadband (from infrared to ultraviolet) and flat response, exceptional chemical and thermal stability, real-time measurement, and energy savings, make the device a promising candidate for next-generation laser detectors and laser energy/power meters.

Zhang, G.-Y.; Zheng, H.-R.; Zhang, X.-Y.; Gao, D.-L.; Zhang, P.-X.; Habermeier, H.-U.

2012-09-01

456

Compartment effects in hemodialysis.  

PubMed

Compartment effects in hemodialysis are important because they reduce the efficiency of removal of the compartmentalized solute during dialysis. The dialyzer can only remove those waste products that are presented to it, and then only in proportion to the concentration of the solute in the blood. Classically a two-compartment system has been modeled, with the compartments arranged in series. Because modeling suggests that the sequestered compartment is larger than the accessible compartment, an assumption has been made that the sequestered compartment is the intracellular space. For urea and other solutes that move easily across many cell membranes, compartmentalization may be flow related, that is, related to sequestration in organs (muscle, skin, bone). Although mathematically urea rebound and mass balance can be described with either model, the flow-related model best explains data showing that urea rebound after dialysis is increased during ultrafiltration, diminished during high cardiac output states, and also reduced during exercise. Whether compartmentalization is increased in vasoconstricted intensive care unit patients receiving acute dialysis remains an open question. PMID:11489202

Schneditz, D; Daugirdas, J T

2001-01-01

457

The Ratchet Effect  

PubMed Central

Objective: To describe the previously unexamined association between admissions to hospital with chronic disease and changes in all-cause health service utilization over time. Research Design: A cohort study examining the population of Western Australia with hospitalizations for chronic disease from 2002 to 2010. A “rolling” clearance period is used to define “cardinal events,” that is, a disease-specific diagnosis upon hospital admission, where such an event has not occurred in the previous 2 years. Changes in the rate of cardinal events associated with diagnoses of heart failure, type 2 diabetes, chronic obstructive pulmonary disease, cataract with diabetes, asthma, and dialysis are examined. Health service utilization (defined as inpatient days or emergency department presentations) 6 years preceding and 4 years following such events is presented. Results: Cardinal events make up 40%–60% of all chronic disease admissions. A previously undescribed ratchet effect following cardinal events specifically associated with type 2 diabetes, heart failure, and chronic obstructive pulmonary disease is observed. This involves a 2- to 3-fold increase in inpatient days and emergency department presentations that are sustained for at least 4 years. Conclusions: Cardinal events represent an important reference point to understand the impact of chronic disease on health service utilization. Events that herald such a marked transition in health service demand have not been previously described. PMID:25054825

Tenneti, Raji; Marsh, Julie; Bolt, Sarah E.; Kemp, Anna; Firth, Laura; Murray, Kevin; Turlach, Berwin; Vickery, Alistair

2014-01-01

458

Landslides - Cause and effect  

USGS Publications Warehouse

Landslides can cause seismic disturbances; landslides can also result from seismic disturbances, and earthquake-induced slides have caused loss of life in many countries. Slides can cause disastrous flooding, particularly when landslide dams across streams are breached, and flooding may trigger slides. Slope movement in general is a major process of the geologic environment that places constraints on engineering development. In order to understand and foresee both the causes and effects of slope movement, studies must be made on a regional scale, at individual sites, and in the laboratory. Areal studies - some embracing entire countries - have shown that certain geologic conditions on slopes facilitate landsliding; these conditions include intensely sheared rocks; poorly consolidated, fine-grained clastic rocks; hard fractured rocks underlain by less resistant rocks; or loose accumulations of fine-grained surface debris. Field investigations as well as mathematical- and physical-model studies are increasing our understanding of the mechanism of slope movement in fractured rock, and assist in arriving at practical solutions to landslide problems related to all kinds of land development for human use. Progressive failure of slopes has been studied in both soil and rock mechanics. New procedures have been developed to evaluate earthquake response of embankments and slopes. The finite element method of analysis is being extensively used in the calculation of slope stability in rock broken by joints, faults, and other discontinuities. ?? 1976 International Association of Engineering Geology.

Radbruch-Hall, D. H.; Varnes, D. J.

1976-01-01

459

(Limiting the greenhouse effect)  

SciTech Connect

Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

Rayner, S.

1991-01-07

460

Effectively Rebutting Climate Misinformation  

NASA Astrophysics Data System (ADS)

Climate science faces one of the best funded misinformation campaigns in history. The challenge for climate communicators is that misinformation is extremely difficult to dislodge, even after people understand that it's incorrect. Understanding how the human brain processes information is crucial to successful rebuttal. To avoid the danger of reinforcing misinformation (known as the 'backfire effect'), emphasis should be on positive facts, not the myth. Another key to dislodging myths is replacing them with an alternate narrative. In order to provide a narrative about arguments that misrepresent climate science, a broader understanding of how these arguments mislead is required. Movements that deny a scientific consensus have 5 characteristics in common and these also apply to climate denial. The arguments against the scientific consensus involve conspiracy theories, fake experts, cherry picking, logical fallacies and misrepresentation or impossible expectations. Learning to identify these rhetorical techniques is an important tool in the climate communication toolbox. I discuss examples of misrepresentations of climate science and the rhetorical techniques employed. I demonstrate how to respond to these arguments by explaining the facts of climate science while in the process, providing an alternate narrative.

Cook, J.

2011-12-01

461

Effective training methodology  

SciTech Connect

Training has become an important part of facility operation in the Department of Energy (DOE) complex. Ongoing changes in DOE requirements dictate that facilities must react to those changes promptly and effectively. This paper presents training techniques particularly suited to training adults, as contrasted with the educational process that most of the authors are familiar with as a result of their primary, secondary and perhaps college educations. DOE has established the Central Training Academy in Albuquerque for the purpose of providing specialized training to persons throughout the complex. However, much of the training for facility operating personnel must necessarily be conducted at those facilities, either by dedicated trainers or by persons who conduct training as a part-time activity. Techniques outlined in this paper should be of particular interest to persons involved in training at DOE facilities. Training should be designed with recognition that adults have real life experiences, which they often like to share; they also like to actively participate in the learning process. Participatory lecture, demonstration and practical exercise instructional methods are particularly suited to training of adults. Proper questioning techniques can be used to increase involvement and to obtain the feedback required to determine if learning has taken place. Setup of the room used for training and properly designed training aids can enhance the learning experience. Finally, testing should be used at the proper time and should always be designed around training objectives.

Crain, B. Jr. [Science Applications International Corp., Aiken, SC (United States)

1995-12-31

462

The Second Mössbauer Effect  

NASA Astrophysics Data System (ADS)

"The Second Mössbauer Effect" was the headline of the "Spiegel" (a German weekly journal like the "Times") from May 13, 1964 for announcing the foundation of the "Physik-Department" at the Technische Hochschule München (THM), as it was still called at this time. Maier-Leibnitz was irritated by this headline because the article did not mention at all his contribution to the consolidation of the structure of the three physics institutes (Experimental, Technical, and Theoretical Physics) in the beginning of the sixties. Already in the late fifties ML's Institute for Technical Physics was overloaded with students working on their diploma or doctoral theses, because research in the new field of applied nuclear physics was very attractive and ML had for each student who applied an interesting research project. In the average, ML had to supervise between 150-200 diploma students, an impossible task. So, young postdoctoral students had to help him out by taking over the duties of professors. In a letter to the Bavarian Ministry of Education and Arts in 1957 he complained: "The directors of the institutes are hopelessly surcharged and the institutes are overcrowded, the resources for research projects are totally insufficient and lots of time and energy is wasted for finding additional resources."

Kienle, Paul

463

Paper field effect transistor  

NASA Astrophysics Data System (ADS)

In this paper we report the use of a sheet of cellulose fiber-based paper as the dielectric layer used in oxide based semiconductor thin film field-effect transistors (FETs). In this new approach we are using the cellulose fiber-based paper in an "interstrate" structure since the device is build on both sides of the cellulose sheet. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>30 cm2/Vs), drain-source current on/off modulation ratio of approximately 104, near-zero threshold voltage, enhancement n-type operation and sub-threshold gate voltage swing of 0.8 V/decade. The cellulose fiber-based paper FETs characteristics have been measured in air ambient conditions and present good stability. The obtained results outpace those of amorphous Si TFTs and rival with the same oxide based TFTs produced on either glass or crystalline silicon substrates. The compatibility of these devices with large-scale/large-area deposition techniques and low cost substrates as well as their very low operating bias delineates this as a promising approach to attain high-performance disposable electronics like paper displays, smart labels, smart packaging, RFID and point-of-care systems for self analysis in bio-applications, among others.

Fortunato, E.; Correia, Nuno; Barquinha, Pedro; Costa, Cláudia; Pereira, Luís; Gonçalves, Gonçalo; Martins, Rodrigo

2009-02-01

464

The photorefractive effect  

SciTech Connect

When Arthur Ashkin and his colleagues at Bell Laboratories first noticed the photorefractive effect some 25 years ago, they considered the phenomenon a curiosity at best and a complete nuisance at worst. Today photorefractive materials are being shaped into components for a new generation of computers that exploit light instead of electricity. During the past 25 years investigators have discovered a wide variety of photorefractive materials, including insulators, semiconductors and organic compounds. Photorefractive materials, like film emulsions, change rapidly when exposed to bright light, respond slowly when subjected to dim light and capture sharp detail when struck by some intricate pattern of light. Unlike film, photorefractive materials are erasable: images can be stored or obliterated at whim or by design. By virtue of their sensitivity, robustness, and unique optical properties, photorefractive materials have the potential to be fashioned into data-processing elements for optical computers. In theory, these devices would allow optical computers to process information at much faster rates than their electronic counterparts. Employing photorefractive materials, workers have already developed the optical analogue to the transistor: if two laser beams interact within a photorefractive material, one beam can control, switch or amplify the second beam. Photorefractive materials also lie at the heart of devices that trace the edges of images, that connect networks of lasers and that store three-dimensional images.

Pepper, D.M. (Pepperdine Univ., CA (USA)); Kukhtarev, N.V. (Institute of Physics, Kiev (Ukrainian SSR))

1990-10-01

465

The effect of simultaneous substitution on the electronic band structure and thermoelectric properties of Se-doped Co3SnInS2 with the Kagome lattice  

NASA Astrophysics Data System (ADS)

The thermoelectric properties and electronic band structures for Se-doped Co3SnInS2 were examined. The parent compound of this material (Co3Sn2S2) has two kinds of Sn sites (Sn1 and Sn2 sites). The density functional theory (DFT) calculations show that the indium substitution at the Sn2 site induces a metallic band structure, on the other hand, a semiconducting band structure is obtained from substitution at the Sn1 site. However, according to the previous reports, since the indium atom prefers to replace the tin atom at the Sn1 site rather than the Sn2 site, the resistivity of Co3SnInS2 shows semiconducting-like behavior. In this study we have demonstrated that metallic behavior and a decrease in resistivity for Se-doped Co3SnInS2 occurs without suppression of the Seebeck coefficient. From the DFT calculations, when the selenium content is above 0.5, the total crystallographic energy shows that a higher indium occupancy at Sn2 site is more stable. Therefore, it is suggested that the selenium doping suppress the site preference for indium substitution. This is one of the possible explanations for the metallic conductivity observed in Se-doped Co3SnInS2

Fujioka, Masaya; Shibuya, Taizo; Nakai, Junya; Yoshiyasu, Keigo; Sakai, Yuki; Takano, Yoshihiko; Kamihara, Yoichi; Matoba, Masanori

2014-12-01

466

Effect of sintering in ball-milled K{sub 2}Bi{sub 8}Se{sub 13} thermoelectric nano-composites  

SciTech Connect

K{sub 2}Bi{sub 8}Se{sub 13} has many attractive features for thermoelectric applications. Recently, K{sub 2}Bi{sub 8}Se{sub 13}-based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated based on powder technology techniques. The Seebeck coefficient has been enhanced while the thermal conductivity has been decreased presenting, thus, interesting behavior. The behavior of the materials under heat treatment conditions is now of interest, as the application of sintering process is necessary for the development of thermoelectric modules. In this work, the crystallization of the K{sub 2}Bi{sub 8}Se{sub 13}-based nano-composites is studied using Differential Scanning Calorimetry. The results show that crystallization follows a multiple-step process with different activation energies. The thermoelectric properties are also discussed in the range that crystallization occurs. - Graphical Abstract: {beta}-K{sub 2}Bi{sub 8}Se{sub 13}-based nanocomposites follow a multiple-step crystallization process. Highlights: Black-Right-Pointing-Pointer K{sub 2}Bi{sub 8}Se{sub 13}-based composites consisting of nanocrystalline and amorphous phases. Black-Right-Pointing-Pointer Sintering results multiple-step crystallization with variable activation energies. Black-Right-Pointing-Pointer Thermoelectric properties follow a step-like behavior during sintering. Black-Right-Pointing-Pointer Properties are attributed to the strain relaxation, nucleation and grain growth.

Hatzikraniotis, E. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)] [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Ioannou, M. [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus)] [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus); Chrissafis, K. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)] [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chung, D.Y. [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Paraskevopoulos, K.M. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)] [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kyratsi, Th., E-mail: kyratsi@ucy.ac.cy [Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia (Cyprus)

2012-09-15

467

The gap between effect of drugs and effectiveness of treatments.  

PubMed

Despite profound effects on the immune system, drugs for multiple sclerosis (MS) therapy have shown only moderate treatment effectiveness. The approved drugs, interferon (IFN)-beta and glatiramer acetate, have a number of effects on the immune system that could interfere with the disease processes in MS but are only able to reduce the relapse rate by 30% and have little or no effect on disease progression. The new targeted immune therapies, campath-1H and natalizumab, have shown immense treatment effectiveness as for inflammation-related disease manifestations, i.e. relapses and MRI activity, but an effect on long-term disease progression has not yet been demonstrated. There are several explanations of the gap between drug effects and treatment effectiveness of which some are related to the properties of the immune system and some are related to the properties of drugs used for treatment of MS. To fill the gap we need to have drugs that both effectively and safely eliminate the inflammation and in addition have neuroprotective properties. However, this may not be obtained from a single drug but may require combinations of drugs with different actions on the disease processes. PMID:17362994

Sorensen, Per Soelberg

2007-08-15

468

Bronchodilating effect and anabolic effect of inhaled procaterol.  

PubMed

While the use of oral beta (2)-agonists by athletes is prohibited because of their anabolic effects, some inhaled beta (2)-agonists can be used in accordance with the World Anti-Doping Agency regulations. We examined the dose disparity between the bronchodilating effect and anabolic effect of inhaled procaterol, a selective beta (2)-agonist, to determine if the drug might be effective for athletes with asthma. Intact rats were given nebulized procaterol at 0.001, 0.01, 0.1 and 1 mg/mL by inhalation, and its inhibitory effect on carbachol-induced bronchoconstriction was evaluated. Castrated rats were given nebulized procaterol at 0.03, 0.1, 0.3 and 1 mg/mL by inhalation 3 times a day for 14 days, and anabolic markers (body weight gain, weight of the levator ani muscle and gastrocnemius muscle) were measured. At 0.01 mg/mL and higher, procaterol dose-dependently inhibited carbachol-induced bronchoconstriction with a significant effect. At doses of up to 0.3 mg/mL, there were no signs indicating an anabolic effect of procaterol. At 1 mg/mL, however, a slight but statistically significant increase in the weight of the levator ani muscle was observed with no significant changes in other anabolic markers. It was suggested that inhaled procaterol might be useful for athletes with asthma because of the big dose disparity between its bronchodilating effect and anabolic effect in rats. PMID:18461498

Ikezono, K; Maeda, T; Kamata, M; Mori, T; Yabuuchi, Y

2008-11-01

469

Effective Sizes for Subdivided Populations  

PubMed Central

Many derivations of effective population sizes have been suggested in the literature; however, few account for the breeding structure and none can readily be expanded to subdivided populations. Breeding structures influence gene correlations through their effects on the number of breeding individuals of each sex, the mean number of progeny per female, and the variance in the number of progeny produced by males and females. Additionally, hierarchical structuring in a population is determined by the number of breeding groups and the migration rates of males and females among such groups. This study derives analytical solutions for effective sizes that can be applied to subdivided populations. Parameters that encapsulate breeding structure and subdivision are utilized to derive the traditional inbreeding and variance effective sizes. Also, it is shown that effective sizes can be determined for any hierarchical level of population structure for which gene correlations can accrue. Derivations of effective sizes for the accumulation of gene correlations within breeding groups (coancestral effective size) and among breeding groups (intergroup effective size) are given. The results converge to traditional, single population measures when similar assumptions are applied. In particular, inbreeding and intergroup effective sizes are shown to be special cases of the coancestral effective size, and intergroup and variance effective sizes will be equal if the population census remains constant. Instantaneous solutions for effective sizes, at any time after gene correlation begins to accrue, are given in terms of traditional F statistics or transition equations. All effective sizes are shown to converge upon a common asymptotic value when breeding tactics and migration rates are constant. The asymptotic effective size can be expressed in terms of the fixation indices and the number of breeding groups; however, the rate of approach to the asymptote is dependent upon dispersal rates. For accurate assessment of effective sizes, initial, instantaneous or asymptotic, the expressions must be applied at the lowest levels at which migration among breeding groups is nonrandom. Thus, the expressions may be applicable to lineages within socially structured populations, fragmented populations (if random exchange of genes prevails within each population), or combinations of intra- and interpopulation discontinuities of gene flow. Failure to recognize internal structures of populations may lead to considerable overestimates of inbreeding effective size, while usually underestimating variance effective size. PMID:8307332

Chesser, R. K.; Rhodes-Jr., O. E.; Sugg, D. W.; Schnabel, A.

1993-01-01

470