Signatures of electron-boson coupling in half-metallic ferromagnet Mn5_5Ge3_3: study of electron self-energy Σ(ω)\Sigma(\omega) obtained from infrared spectroscopy

We report results of our infrared and optical spectroscopy study of a half-metallic ferromagnet Mn$_5$Ge$_3$. This compound is currently being investigated as a potential injector of spin polarized currents into germanium. Infrared measurements have been performed over a broad frequency (50 - 50000 cm$^{-1}$) and temperature (10 - 300 K) range. From the complex optical conductivity $\sigma(\omega)$ we extract the electron self-energy $\Sigma(\omega)$. The calculation of $\Sigma(\omega)$ is based on novel numerical algorithms for solution of systems of non-linear equations. The obtained self-energy provides a new insight into electron correlations in Mn$_5$Ge$_3$. In particular, it reveals that charge carriers may be coupled to bosonic modes, possibly of magnetic origin

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)

Temperature Induced Changes in Morphology and Structure of Tio2-al2o3 Fibers

Electrospinning of a sol-gel and polymer mixture is used to produce titania-alumina (TiO2–Al2O3) fibers with diameters ranging from 200 to 800 nm. These composite metal-oxide fibers were calcined at various temperatures and their morphology is studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The decrease in the average diameter of the fibers with increasing temperature is observed. Powder X-ray diffraction (XRD) reveals that up to 800 °C the composite fibers have anatase titania structure whereas at 900 °C the fibers exhibit mixture of anatase and rutile phases. It is found that specific surface area decreases as a function of temperature in the 700–900 °C range. The change in phase (anatase-to-rutile) and the increase in crystallite size occur simultaneously. The presence of smaller amount of amorphous alumina in the primarily titania-based structure seems to play the role in stabilizing the anatase phase

Selective emitters for thermophotovoltaics: erbia-modified electrospun titania nanofibers

Titania nanofibers were synthesized by electrospinning and characterized with scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The nanofibers were annealed to 773 K to achieve the anatase titania crystal structure, and to 1173 K to obtain the rutile phase. In order to create erbia-containing titania nanofibers, erbium (III) oxide particles were added to the pre-cursor solution before electrospinning. After pyrolysis the titania nanofibers supported and encapsulated the erbia particles. Temperature-dependent near-infrared emission spectra demonstrate that the erbia-containing nanofibers emit selectively in the range 6000–7000 cm−1. Because of their large surface to volume ratios and narrow-band optical emission, these nanofibers can be used as selective emitters for thermophotovoltaic applications

Selective Emitters for Thermophotovoltaics: Erbia-modified Electrospun Titania Nanofibers

Titania nanofibers were synthesized by electrospinning and characterized with scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The nanofibers were annealed to 773 K to achieve the anatase titania crystal structure, and to 1173 K to obtain the rutile phase. In order to create erbia-containing titania nanofibers, erbium (III) oxide particles were added to the pre-cursor solution before electrospinning. After pyrolysis the titania nanofibers supported and encapsulated the erbia particles. Temperature-dependent near-infrared emission spectra demonstrate that the erbia-containing nanofibers emit selectively in the range 6000–7000 cm−1. Because of their large surface to volume ratios and narrow-band optical emission, these nanofibers can be used as selective emitters for thermophotovoltaic applications

Erbia-modified Electrospun Titania Nanofibres for Selective Infrared Emitters

Tetraisopropyl titanate (TPT) was mixed with a solution of polyvinylpyrrolidone (PVP) and the solution electrospun into nanofibres. Thermal annealing at 900 °C was used to pyrolyse the PVP, leaving nanofibres of rutile-phase titania. Erbium (III) oxide particles were also added into the solution before electrospinning, and selectively modified the near-infrared optical properties of the titania nanofibres as verified by both absorption and emission spectra. We thereby demonstrate the production of high-temperature optically functionalized nanostructures that can be used in a thermophotovoltaic energy conversion system

Erbia-modified electrospun titania nanofibres for selective infrared emitters

Tetraisopropyl titanate (TPT) was mixed with a solution of polyvinylpyrrolidone (PVP) and the solution electrospun into nanofibres. Thermal annealing at 900 °C was used to pyrolyse the PVP, leaving nanofibres of rutile-phase titania. Erbium (III) oxide particles were also added into the solution before electrospinning, and selectively modified the near-infrared optical properties of the titania nanofibres as verified by both absorption and emission spectra. We thereby demonstrate the production of high-temperature optically functionalized nanostructures that can be used in a thermophotovoltaic energy conversion system

Many Labs 5: Registered Replication Report of LoBue & DeLoache (2008)

Across three studies, LoBue and DeLoache (2008) provided evidence suggesting that both young children and adults exhibit enhanced visual detection of evolutionarily relevant threat stimuli (as compared with nonthreatening stimuli). A replication of their Experiment 3, conducted by Cramblet Alvarez and Pipitone (2015) as part of the Reproducibility Project: Psychology (RP:P), demonstrated trends similar to those of the original study, but the effect sizes were smaller and not statistically significant. There were, however, some methodological differences (e.g., screen size) and sampling differences (the age of recruited children) between the original study and the RP:P replication study. Additionally, LoBue and DeLoache expressed concern over the choice of stimuli used in the RP:P replication. We sought to explore the possible moderating effects of these factors by conducting two new replications—one using the protocol from the RP:P and the other using a revised protocol. We collected data at four sites, three in Serbia and one in the United States (total N = 553). Overall, participants were not significantly faster at detecting threatening stimuli. Thus, results were not supportive of the hypothesis that visual detection of evolutionarily relevant threat stimuli is enhanced in young children. The effect from the RP:P protocol (d = −0.10, 95% confidence interval = [−1.02, 0.82]) was similar to the effect from the revised protocol (d = −0.09, 95% confidence interval = [−0.33, 0.15]), and the results from both the RP:P and the revised protocols were more similar to those found by Cramblet Alvarez and Pipitone than to those found by LoBue and DeLoache