Superior Thermoelectric Performance of SiGe Nanowires Epitaxially Integrated into Thermal Micro-Harvesters

Semiconductor nanowires have demonstrated fascinating properties with applications in a wide range of fields, including energy and information technologies. Particularly, increasing attention has focused on SiGe nanowires for applications in a thermoelectric generation. In this work, a bottom-up vapour-liquid-solid chemical vapour Deposition methodology is employed to integrate heavily boron-doped SiGe nanowires on thermoelectric generators. Thermoelectrical properties –, i.e., electrical and thermal conductivities and Seebeck coefficient – of grown nanowires are fully characterized at temperatures ranging from 300 to 600 K, allowing the complete determination of the Figure-of-merit, zT, with obtained values of 0.4 at 600 K for optimally doped nanowires. A correlation between doping level, thermoelectric performance, and elemental distribution is established employing advanced elemental mapping (synchrotron-based nano-X-ray fluorescence). Moreover, the operation of p-doped SiGe NWs integrated into silicon micromachined thermoelectrical generators is shown over standalone and series- and parallel-connected arrays. Maximum open circuit voltage of 13.8 mV and power output as high as 15.6 µW cm⁻² are reached in series and parallel configurations, respectively, operating upon thermal gradients generated with hot sources at 200 °C and air flows of 1.5 m s⁻¹. These results pave the way for direct application of SiGe nanowire-based micro-thermoelectric generators in the field of the Internet of Things.     

Influence of Austempering Temperature on Microstructure and Mechanical Properties of High-Silicon Carbide-Free Bainitic Steel

The microstructural evolution of a novel high-silicon carbide-free bainitic steel at different austempering temperatures is investigated. The microstructure is evaluated by means of optical and electron microscopy, X-ray diffraction, microhardness, and nanohardness. Results show a variation in the amount of stabilized retained austenite changing the temperature of the isothermal treatment. In particular, it is observed an increase in the retained austenite volume fraction increasing the temperature up to 350 °C, while further increase leads to a reduction. Moreover, increasing the isothermal holding temperature from 250 °C, through 300, 350, and 370 °C, a progressive bainite coarsening and an increase in the amount of stabilized carbon-enriched retained austenite are observed. Tensile tests reveal an excellent combination of mechanical properties: mechanical strength in the range 1276–1988 MPa and total elongation 0.18–0.44.     

Regional science: economy and geography in France and French-speaking countries

The objective of this paper is to assess the French-speaking countries contributions to regional science since its creation in the 1950s. France, and other French-speaking countries, very quickly adhered to the approach of the founding fathers of regional science. French-language research developed for several years without maintaining major relations with the main streams that flow through regional science. However, the years 2000 and 2010 saw the emergence of streams of thought that strongly irrigate at the international level. The authors of this paper are part of this movement. Here we trace the origins and development of the French-speaking contribution to regional sciences, while highlighting the originality of the French-language approach. First, the question of academic and institutional contexts is discussed, with the role of the founders and the peculiar place of Journals and public institutions. Further sections analyse the main contributions coming from economics (local systems of production and innovation, innovative milieus and proximity analysis) and geography (regional development at a global scale, and urban systems and complexity). We conclude with cross-disciplinary contributions including intra-urban organization and mobility, territorial governance and territorial development, as well as other approaches to the social sciences, in the contemporary issues of city and territorial governance.     

Exploring the biomechanics of walking and crowd “flow”

Crowd movement simulation models are generally based on aggregated speed and flow data collected more than 50 years ago. There appears to be no validated modelling capability to include the impact of recent and future changes in population demographics, resulting from an ageing population and increasing obesity rates. New analytical approaches and data gathering are required to successfully model crowd movement and safety for current and future generations. This study carried out (a) a review of the primary components of crowd movement, demographics and analytical techniques, (b) prototype experiments to investigate age-related aspects of space and potential points of contact and (c) a new predictive model for crowd flow analysis based on pedestrian biomechanics and anthropometric data. The model uses the physical space taken up by the biomechanical walking process and the spatial buffer between points of potential contact with other pedestrians to predict the speed of movement at different levels of congestion. The new analytical model was used to predict single file speeds (for people with different demographics in congested space), which compared well with published experimental data. The next steps for model development for wider “flows” and additional experiments to provide data sets for wider demographics are also proposed.     

Nanoemulsions of Acai Oil: Physicochemical Characterization for the Topical Delivery of Antifungal Drugs

Nanoemulsion-based acai oil was obtained by the phase inversion method using two nonionic surfactants, Ceteareth-20 (Brij™ CS20) and polyoxyethylene-hydrogenated castor oil (Croduret™ 50), with the concentration of each surfactant varying from 7 to 10 %. The formulation with 10 % Brij CS20 presented the best values for droplet size, zeta potential, and polydispersity index (PDI). Ketoconazole was incorporated into this formulation, with an encapsulation efficiency of 98.31 % and equally good zeta potential, droplet size, and PDI, and spherical shape when observed by transmission electron microscopy. Overall, nanoemulsions of acai oil proved to be a good vehicle for imidazole antifungals such as ketoconazole.     

Kinetic study of uranium removal from aqueous solutions by macaúba biochar

Abstract

Macaúba (Acronomia aculeata) is a palm tree native of the Brazilian savanna and a valuable renewable source of vegetable oil for human consumption and biodiesel production. In this study, the potentiality of the macaúba endocarp for biochar (BC) production was demonstrated. Moisture, density, elemental and molecular composition, along with TGA, FTIR, and XRD analyses were performed for the endocarp. Adsorption of uranyl ions, U(VI), from aqueous solutions was studied by batch technique using BC produced by slow pyrolysis of the endocarp at 350?°C (BC350). The effect of contact time on the removal of U(VI) by BC350 was evaluated. Linear and non-linear kinetics models were employed and the best fit for the experimental data was achieved for pseudo-first order non-linear model. The adsorption equilibrium was attained after 180?min of contact time and the equilibrium adsorption capacity achieved was of 400?mg g^?1. Finally, BC350 was characterized by SEM, FTIR, WDXRF, and XRD techniques.     

Conceptually derived treatments for sexual aggressors.

The relative absence of theoretical models has interfered with progress in the assessment and treatment of sexual aggressors. G. C. Hall and R. Hirschman (see record 1992-05851-001) have proposed a conceptual model of sexual aggression that has treatment implications. Physiological, cognitive, affective, and developmentally related personality precursors correspond to subtypes of sexual aggressors. Each subtype, the associated primary motivational precursor, a case example, and treatment methods that could be used for treating each subtype are presented here. There is some evidence of effective interventions for each of the motivational precursors. However, additional research is needed on the effectiveness of treatments in reducing recidivism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Defensive Zeal and the Uncertain Self: What Makes You So Sure?

In Studies 1-3, undergraduates with high self-esteem (HSEs) reacted to personal uncertainty-threats with compensatory conviction about unrelated issues and aspects of the self. In Study 1 HSEs reacted to salience of personal dilemmas with increased implicit conviction about self-definition. In Study 2 they reacted to the same uncertainty-threat with increased explicit conviction about social issues. In Study 3, HSEs (particularly defensive HSEs, i.e., with low implicit self-esteem; C. H. Jordan, S. J. Spencer, & M. P. Zanna, 2003) reacted to uncertainty about a personal relationship with compensatory conviction about social issues. For HSEs in Study 4, expressing convictions about social issues decreased subjective salience of dilemma-related uncertainties that were not related to the social issues. Compensatory conviction is viewed as a mode of repression, akin to reaction formation, that helps keep unwanted thoughts out of awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RECOGNITION OF TWO LIPASES FROM BARLEY AND GREEN MALT

Lipase was extracted from ground samples of germinating and ungerminated barley, using the detergent Triton X-100. Enzyme activity, measured by the release of oleic acid from radioactively labelled triolein, was approximately half that in suspensions of barley flour. Two distinct lipases, both active at neutral pHs, and having similar molecular weights (around 400,000) but differing in their ionic properties, were isolated from barley. The more abundant lipase was found mainly in the embryo, while the other was located in the endosperm. Both total and extractable lipase activity increased during germination.