Probing Magnetic Excitations and Correlations in Single and Coupled Spin Systems with Scanning Tunneling Spectroscopy

Spectroscopic measurements with low-temperature scanning tunneling microscopes have been used very successfully for studying not only individual atomic or molecular spins on surfaces but also complexly designed coupled systems. The symmetry breaking of the supporting surface induces magnetic anisotropy which lead to characteristic fingerprints in the spectrum of the differential conductance and can be well understood with simple model Hamiltonians. Furthermore, correlated many-particle states can emerge due to the interaction with itinerant electrons of the electrodes, making these systems ideal prototypical quantum systems. In this manuscript more complex bipartite and spin-chains will be discussed additionally. Their spectra enable to determine precisely the nature of the interactions between the spins which can lead to the formation of new quantum states which emerge by interatomic entanglement.Comment: 46 pages, 21 figure

Crawl space assisted heat pump

A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described

Tangent circles in the hyperbolic disk

Constructions of tangent circles in the hyperbolic disk, interpreted in Euclidean geometry, give us examples of four mutually tangent circles. These are shown to satisfy Descartes\u27s Theorem for tangent circles. We also show that the Archimedes twin circles in the hyperbolic arbelos are usually not hyperbolic congruent, even though they are Euclidean congruent. We include a few construction instructions because all items under consideration require surprisingly few steps

The Effects of Multiple Accommodations on Student Engagement and Work Completion in Fifth Grade Students with Reading Disabilities

The purpose of this study was to investigate the effects of several accommodations that may benefit fifth grade students who have been identified with a reading disability in the general education classroom in order to increase engagement and work completion during English Language Arts instruction. Data was collected through teacher surveys, teacher interviews, and on-task/off-task observations. Surveys were conducted prior to the study, mid-study, and post-study. Teacher interviews were conducted at the planning meeting biweekly and observations were completed prior to the study, mid-study, and post study. Due to the COVID-19 pandemic, the study was not able to be conducted the way it was written so an autoethnographic research design was used, through journal entry data, to determine the main themes I experienced during the COVID-19 extended school closure. These themes included: communication, collaboration, technology, and remote teaching and learning

In Situ Characterization and Modelling of Drying Dynamics for Scalable Printing of Hybrid Perovskite Photovoltaics

Hybrid perovskite photovoltaics could play a vital role in future’s renewable energy production. However, there are still severe challenges when scaling the technology. In this work, perovskite solution films drying in laminar and slot-jet air flows are investigated extensively by optical in situ characterization. The main results are a quantitative model of perovskite drying dynamics and a novel in situ imaging technique – yielding valuable predictions for large-scale perovskite fabrication