arXiv subjects

David Carroll

Publications and source records attributed to David Carroll.

3 recordsLinked to original sources

arXiv2025

SIMLA: The Spitzer Infrared Spectrograph Mapping Legacy Archive

We present the Spitzer/IRS Mapping Legacy Archive (SIMLA); a complete set of mid-infrared spectral cubes built from low-resolution mapping-mode fixed-target observations from Spitzer/IRS (5.2-38 micron, R~60-130). Contained in this dataset are spectral maps for several hundred spatially-resolved and unresolved objects, including galaxies, molecular clouds, supernova remnants, HII regions, and more. Each cube has been carefully treated to remove astronomical foregrounds and backgrounds as well as detector effects using a novel pipeline. Cube assembly was facilitated by the CUBISM code, which included automatic detection and removal of bad pixels. We describe the SIMLA pipeline for reducing and validating the cubes, and we show that synthetic photometry derived from SIMLA spectra and corresponding WISE photometry typically agree within a few percent. SIMLA products and documentation related to their use will soon be available at the NASA/IPAC Infrared Science Archive (DOI:10.26131/IRSA655).

astro-ph.IM↗

arXiv2025

A Brief Perspective on Piezotronic and Thermoelectric Coupling: Flexible Platforms for Synergistic Energy Scavenging and Peltier-Caloric Effects

Advances in the development of flexible piezoelectric and thermoelectric materials have provided an important avenue for the exploration of energy scavenging through the thermodynamic-coupling of orthogonal energy-scavenging modalities. This has led to a body of work creating hybrid thermo/piezo-electric generator devices (T/PEGs) in which the two effects become thermodynamically entangled. Based on hetero- thin film architectures, such devices can exhibit a surprising power generation characteristic which is non-additive between the two energy-scavenging effects. For example, when the thermoelectric and piezoelectric effects are strongly coupled by their proximal fields, the efficacy of energy scavenging can be made to exceed that of the two effects independently. In this review of such effects, a basic coupled heat engine model is shown to provide insight into the origins of synergistic power generation. These models however, suggest the emergence of other combined thermodynamic properties such as the kinetic Peltier-Caloric Effect (PCE) traced to Onsager reciprocity. The recent observation of this effect in multicomponent systems is confirmation of the limited perspective of thermodynamic separability.

cond-mat.mtrl-sci↗

arXiv2015

Periodic Points on Shifts of Finite Type and Commensurability Invariants of Groups

We explore the relationship between subgroups and the possible shifts of finite type (SFTs) that can be defined on the group. In particular, we investigate two group invariants, weak periodicity and strong periodicity, defined via symbolic dynamics on the group. We show that these properties are invariants of commensurability. Thus, many known results about periodic points in SFTs defined over groups are actually results about entire commensurability classes. Additionally, we show that the property of being not strongly periodic (also called weakly aperiodic) is preserved under extensions with finitely generated kernels. We conclude by raising questions and conjectures about the relationship of these invariants to the geometric notions of quasi-isometry and growth.

math.GR↗