Non-contact ultrasound characterization of paper substrates

Different kinds of paper varying in basis weight, thickness, etc. and finishing characteristics such as cast, gloss, matte were analyzed with and without deposited ink. A 1.7 MHz Ultran non-contact ultrasound focused transducer was operated in the pulse-echo mode to investigate the samples following a raster scan on a 1.5 cm by 1.5 cm area. Both sides of each sample were imaged under this protocol. A pre-designed pattern consisting of some text and a rectangular solid block was printed on the front side of the samples using a Xerox Nuvera120 laser printer and the imaging protocol repeated. C-scan images created from the envelope detected data provide a promising means to investigate and visually differentiate the mechanical properties of the samples as ink is deposited, as well as to differentiate front and back sides of each sample. The second normalized intensity moment and Signal to Noise Ratio (SNR) of the signal envelope are investigated to test their validity to discriminate between different kinds of paper as well as differences in scattering properties when ink is deposited

Going Beyond Promoting: Preparing Students to Creatively Solve Future Problems

While we cannot know what problems the future will bring, we can be almost certain that solving them will require creativity. In this article we describe how our course, a first-year undergraduate mathematics course, supports creative problem solving. Creative problem solving cannot be learned through a single experience, so we provide our students with a blend of experiences. We discuss how the course structure enables creative problem solving through class instruction, during class activities, during out of class assessments, and during in class assessments. We believe this course structure increases student comfort with solving open-ended and ill-defined problems similar to what they will encounter in the real world

Finding the Needles in the Haystacks: High-Fidelity Models of the Modern and Archean Solar System for Simulating Exoplanet Observations

We present two state-of-the-art models of the solar system, one corresponding to the present day and one to the Archean Eon 3.5 billion years ago. Each model contains spatial and spectral information for the star, the planets, and the interplanetary dust, extending to 50 AU from the sun and covering the wavelength range 0.3 to 2.5 micron. In addition, we created a spectral image cube representative of the astronomical backgrounds that will be seen behind deep observations of extrasolar planetary systems, including galaxies and Milky Way stars. These models are intended as inputs to high-fidelity simulations of direct observations of exoplanetary systems using telescopes equipped with high-contrast capability. They will help improve the realism of observation and instrument parameters that are required inputs to statistical observatory yield calculations, as well as guide development of post-processing algorithms for telescopes capable of directly imaging Earth-like planets.Comment: Accepted for publication in PAS

Papier-mach(in)e: Thinking with “sticky” paper in the cloud

There is nothing less about paper and its use when it comes to academic study as we experience increasingly converging media spaces and functionalities of online applications within the screens of our laptops, mobile phones and tablet devices. The paper persists, and the paperless office, classroom and pedagogy become nothing but pure rhetoric. Hence, it is most pertinent to focus on paper and its “stickiness” in maintaining educational structures and practices. Usually hidden from view or neglected in educational technology studies is a consideration on how we think and interact not only with our mind but also with our heads and limbs. This paper will argue that paper has a composite place or bearing, a kind of stickiness to our technologised bodies, digital mobilities and hybrid practices in what I have coined here as papier-mach(in)e. This claim will be supported by evidence that demonstrates how we simply think both practically and pathically and that our mobilities in media and physical spaces are in one form or another meshed with paper. In fact, a drive towards a paperless classroom or pedagogy is without much foundation when it comes to mobilising a sustainable agenda for technology-enhanced learning

Sensitive Probing of Exoplanetary Oxygen via Mid Infrared Collisional Absorption

The collision-induced fundamental vibration-rotation band at 6.4 um is the most significant absorption feature from O2 in the infrared (Timofeyev and Tonkov, 1978; Rinslandet al., 1982, 1989), yet it has not been previously incorporated into exoplanet spectral analyses for several reasons. Either CIAs were not included or incomplete/obsolete CIA databases were used. Also, the current version of HITRAN does not include CIAs at 6.4 um with other collision partners (O2-X). We include O2-X CIA features in our transmission spectroscopy simulations by parameterizing the 6.4 um O2-N2 CIA based on Rinsland et al.(1989) and the O2-CO2 CIA based on Baranov et al. (2004). Here we report that the O2-X CIA may be the most detectable O2 feature for transit observations. For a potentialTRAPPIST-1e analogue system within 5 pc of the Sun, it could be the only O2 detectable signature with JWST (using MIRI LRS) for a modern Earth-like cloudy atmosphere with biological quantities of O2. Also, we show that the 6.4 um O2-X CIA would be prominent for O2-rich desiccated atmospheres (Luger and Barnes, 2015) and could be detectable with JWST in just a few transits. For systems beyond 5 pc, this feature could therefore be a powerful discriminator of uninhabited planets with non-biological "false positive" O2 in their atmospheres - as they would only be detectable at those higher O2 pressures.Comment: Published in Nature Astronom

Metal-ligand ``multiple`` bonding: Revelations in the electronic structure of complexes of high-valent f-elements

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project has been to extend the understanding of the nature of interactions between f-metals and first row elements (important both in natural systems and in ceramics), as well as providing important new information regarding basic differences in the chemical nature of d- and f-metals. By developing preparative routes to novel classes of early actinide and lanthanide complexes in which metal-ligand bonding is formally unsaturated, this project has provided the means to study orbital interactions and charge distribution in these species by physical, chemical, and theoretical means. Evaluation of the physical and chemical characteristics of these species is providing dramatic evidence for the involvement of valence metal orbitals [nf and (n+1)d] in bonding, and is yielding new insights into the factors influencing stability of related species