Thermal Stability of Platinum-Silicon Alloy Films Grown on Langasite Substrates for use in Microwave Acoustic Sensor Technology

Wireless sensors that can operate in temperatures up to 1000°C are widely needed for real time monitoring of large-scale industrial processes. Such sensors will improve efficiency and prevent component failure. Under previous work at UMaine, Surface Acoustic Wave Resonator (SAWR) sensors fabricated on piezoelectric langasite (La3Ga5SiO14) wafers have shown promise for wireless strain measurements at high temperatures. However, there is a major technical challenge in attaching SAWR langasite based sensors to metal parts because the large differences in the coefficient of thermal expansion (CTE) between langasite and metals leads to large thermal stresses and fracture of the associated materials during thermal cycling. Preliminary work resulted in the development of a multilayered adhesive containing graded CTE values using platinum, silicon, zirconium, and copper which showed promising adhesion between langasite and steel. However, problems with the multilayered adhesive include non-uniform bonding leading to irreproducible behavior, film delamination, weakening through oxidation, and lack of thermal stability. This thesis reports on results of experiments performed using facilities in UMaine’s Frontier Institute for Research in Sensor Technologies (FIRST). The thermal stability of PtxSi1-x alloy films deposited on langasite substrates was investigated to create a uniform, reproducible layer to reliably adhere langasite to a copper overlayer. The PtxSi1-x films were deposited to a thickness of ~150nm using an electron beam evaporation technique carried out in ultra-high vacuum. Several PtxSi1-x films were synthesized by co-deposition from elemental Si and Pt sources and then subjected to annealing treatments up to 850°C in vacuum, air, or N2 process gases. The PtSi alloy composition was identified to be the most promising for creating a uniform, thermally stable film as determined from X-ray diffraction and scanning electron microscopy analysis. A 500 nm thick copper layer deposited on a PtSi film using a sputter deposition technique yielded a thermally stable film configuration due to a chemical reaction across the PtSi/Cu interface

Aggressive behavior and the perception of violence.

Carl Rogers (1965) stated that the organism reacts to the field as it is experienced and perceived. This perceptual field is, for the individual, \u27reality 1 . 11 Thus, according to phenomenological theory, experience and perception determine reality and consequently behavior. The present study tests the assumption that perception is related to behavior. The validity of the a perception of violence task as a predictor of rated aggressive behavior is tested. Sex is included as an independent variable because no data are available on sex differences for perception of violence

Radio-star visibility fades observed in the auroral zone, part i scientific report no. 1

Radio star signal visibility fading observed in auroral zone by phase-switching interferomete

Radiowave Scattering Structure In The Disturbed Auroral Ionosphere: Some Measured Properties

Thesis (Ph.D.) University of Alaska Fairbanks, 196

Radiowave scattering structure in the disturbed auroral ionosphere - Some measured properties, volume 1

Quantitative analysis on radio wave scattering in disturbed auroral ionospher

The Amsterdam energy transition roadmap – introducing the City-zen methodology

Purpose – City-zen is an EU-funded interdisciplinary project that aims to develop and demonstrate energy-efficient cities and to build methods and tools for cities, industries and citizens to achieve ambitious sustainability targets. As part of the project, an Urban Energy Transition Methodology is developed, elaborated and used to create Roadmaps, which indicate the interventions needed to get from the current situation to the desired sustainable future state of a city. For one of the partner cities, Amsterdam, such a Roadmap was developed. The paper aims to discuss these issues. Design/methodology/approach – This paper discusses the approach and methodology behind the City-zen Urban Energy Transition Methodology, with its six steps from the initial energy analysis to the roadmap towards a desired future state. The paper will illustrate this by results from the Amsterdam Roadmap study, in numbers and figures. Findings – The Roadmap study of Amsterdam revealed that the city can become energy neutral in its heat demand, but not in the production of sufficient electricity from renewables. Research limitations/implications – Although as yet only applied to the City of Amsterdam, the methodology behind the roadmap can be applied by cities across the world. Practical implications – An enormous effort is required in order to transform, renovate and adapt parts of the city. It was calculated, for instance, how many energy renovation projects, district heating pipes and photovoltaic panels will be annually needed in order to timely become carbon neutral, energy neutral and “fossil free”. Social implications – The technical-spatial content of the Roadmap was presented to stakeholders of the Dutch capital city, such as politicians, energy companies, commercial enterprises, and not least citizens themselves. Although informed by scientific work, the Roadmap appealed too many, demonstrated by the extensive media coverage. Originality/value – The City-zen Methodology builds upon earlier urban energy approaches such as REAP (Tillie et al., 2009), LES (Dobbelsteen et al., 2011) and Energy Potential Mapping (Broersma et al., 2013), but creates a stepped approach that has not been presented and applied to a city as a whole yet. As far as the authors know, so far, an energy transition roadmap has never been developed for an entire city

Evidence for the tongue of ionization under northward interplanetary magnetic field conditions

[1] The activities of the International Ionospheric Tomography Community open up new possibilities of simultaneously imaging the large-scale spatial structure of the ionosphere in different longitude sectors. In the study, tomography receiver chains in Scandinavia and Greenland were used to provide a wide view of the plasma density structure in the winter, magnetic postnoon sector under conditions of stable, positive interplanetary magnetic field B z component. The spatial distributions of the plasma are discussed in light of a high-latitude plasma convection pattern pertinent to the conditions, which is supported by DMSP flow measurements. The observations are consistent with a tongue of dayside photoionization being drawn antisunward by the convection pattern to form an arc of enhanced plasma density around the periphery of the polar cap