First principle electronic, structural, elastic, and optical properties of strontium titanate

We report self-consistent ab-initio electronic, structural, elastic, and optical properties of cubic SrTiO$_{3}$ perovskite. Our non-relativistic calculations employed a generalized gradient approximation (GGA) potential and the linear combination of atomic orbitals (LCAO) formalism. The distinctive feature of our computations stem from solving self-consistently the system of equations describing the GGA, using the Bagayoko-Zhao-Williams (BZW) method. Our results are in agreement with experimental ones where the later are available. In particular, our theoretical, indirect band gap of 3.24 eV, at the experimental lattice constant of 3.91 \AA{}, is in excellent agreement with experiment. Our predicted, equilibrium lattice constant is 3.92 \AA{}, with a corresponding indirect band gap of 3.21 eV and bulk modulus of 183 GPa.Comment: 11 pages, 6 figures,Accepted for publication in AIP Advances (2012

Embodying Difference. An Initial Dialogue

One of the points that ‘Anti-Racism at SSoA: A Call to Action’ calls for is the ‘diversification and contextualisation of the teaching of architectural history’ under the section of ‘equalising and diversifying the curriculum in all aspects’. Throughout the academic year 2020-21, as Humanities and Environment and Technology Leaders, we had regular conversations to reflect, as well as to think how, from our positions, we responded to this call. Our presentation at a recent ACAN Tutor’s Workshop was the platform where we publicly reflected on these initial discussions and suggested steps towards addressing some of the questions from the call in the Humanities and the Environment and Technology modules at the School of Architecture at the University of Sheffield. However, sometimes our conversations went beyond the call, but also sometimes we found ourselves struggling. Sometimes our thoughts took us to different places and experiences, sometimes we ended up having conversations with some of the voices that have influenced our thinking. Most importantly, these conversations brought to the fore, once again, complexities and entanglements, lacks and gaps, legacies and hierarchies that we needed to recognise, acknowledge and embody, to have this conversation to then be able to embody and work towards anti-racism. This piece reflects one initial conversation between the two of us. Whilst we didn’t wish to be named, the dialogue follows the fonts in the paragraphs. Moreover, some of the voices that have inspired and shaped our thinking and practice are also included, in red or quotations

First Disk-Resolved Millimeter Observations Of Io's Surface And SO2 Atmosphere

Aims. In spite of considerable progress in the last two decades, Io's atmosphere remains poorly understood. The goal of this work is to improve our understanding of its spatial distribution, temperature and dynamics. Methods. We present millimeter observations of Io's surface and SO2 atmosphere at 1.4 mm obtained with the IRAM Plateau de Bure Interferometer in January-February 2005. With a synthesized beam of 0.5 x 1.5 '', these observations resolve Io's similar to 1.0 '' disk in the longitudinal/local time direction, and sample the leading and trailing hemispheres of Io. Results. The measured continuum total flux and visibilities show that continuum radiation originates from a depth of at least 1 cm in Io's subsurface. On both the leading and trailing sides, emission in the SO2 216.643 GHz line appears spatially narrower than the continuum, and suggests that the atmosphere covers similar to 80% of the surface on the leading side and similar to 60% on the trailing. On the leading side, disk-resolved spectra yield Doppler shift measurements, indicating a beam-integrated limb-to-limb velocity difference of 330 +/-3 100 m/s in the prograde direction. Such a flow allows an improved fit of disk-averaged SO2 spectra, but its origin remains to be understood. Mean gas temperatures are in the range 130-180 K, in agreement with estimates from IR measurements, and with a tendency for higher trailing vs leading side gas temperatures. On the basis of realistic plume models, we find that the contribution of isolated volcanic plumes to the SO2 emission is small.Astronom

Study of off-diagonal disorder using the typical medium dynamical cluster approximation

We generalize the typical medium dynamical cluster approximation (TMDCA) and the local Blackman, Esterling, and Berk (BEB) method for systems with off-diagonal disorder. Using our extended formalism we perform a systematic study of the effects of non-local disorder-induced correlations and of off-diagonal disorder on the density of states and the mobility edge of the Anderson localized states. We apply our method to the three-dimensional Anderson model with configuration dependent hopping and find fast convergence with modest cluster sizes. Our results are in good agreement with the data obtained using exact diagonalization, and the transfer matrix and kernel polynomial methods.Comment: 10 pages, 8 figure

Developing Scenarios for Product Longevity and Sufficiency

This paper explores the narrative of peoples’ relationships with products as a window on understanding the types of innovation that may inform a culture of sufficiency. The work forms part of the 'Business as Unusual: Designing Products with Consumers in the Loop' [BaU] project, funded as part of the UK EPSRC-ESRC RECODE network (RECODE, 2016) that aims to explore the potential of re-distributed manufacturing (RdM) in a context of sustainability. This element of the project employed interviews, mapping and workshops as methods to investigate the relationship between people and products across the product lifecycle. A focus on product longevity and specifically the people-product interactions is captured in conversations around product maintenance and repair. In exploring ideas of ‘broken’ we found different characteristics of, and motivations for, repair. Mapping these and other product-people interactions across the product lifecycle indicated where current activity is, who owns such activity (i.e. organisation or individual) and where gaps in interactions occur. These issues were explored further in a workshop which grouped participants to look at products from the perspective of one of four scenarios; each scenario represented either short or long product lifespans and different types of people engagement in the design process. The findings help give shape to new scenarios for designing sufficiency-based social models of material flows

Re-examining the electronic structure of germanium: A first-principle study

We report results from an efficient, robust, ab-initio method for self-consistent calculations of electronic and structural properties of Ge. Our non-relativistic calculations employed a generalized gradient approximation (GGA) potential and the linear combination of atomic orbitals (LCAO) formalism. The distinctive feature of our computations stem from the use of Bagayoko-Zhao-Williams-Ekuma-Franklin (BZW-EF) method. Our results are in agreement with experimental ones where the latter are available. In particular, our theoretical, indirect band gap of 0.65 eV, at the experimental lattice constant of 5.66 \AA{}, is in excellent agreement with experiment. Our predicted, equilibrium lattice constant is 5.63 \AA{}, with a corresponding indirect band gap of 0.65 eV and a bulk modulus of 80 GPa. We also calculated the effective masses in various directions with respect to the $\Gamma$ point.Comment: 10 Pages, 3 Figures, and 1 tabl

Duality between Topologically Massive and Self-Dual models

We show that, with the help of a general BRST symmetry, different theories in 3 dimensions can be connected through a fundamental topological field theory related to the classical limit of the Chern-Simons model.Comment: 13 pages, LaTe