Spectral Distortion in a Radially Inhomogeneous Cosmology

The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous spacetime, designed to exactly reproduce a LambdaCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous Big Bang.Comment: 16 pages, 8 figures (added references and clarified discussion; some numbers revised

Gravitational Wave - Gauge Field Oscillations

Gravitational waves propagating through a stationary gauge field transform into gauge field waves and back again. When multiple families of flavor-space locked gauge fields are present, the gravitational and gauge field waves exhibit novel dynamics. At high frequencies, the system behaves like coupled oscillators in which the gravitational wave is the central pacemaker. Due to energy conservation and exchange among the oscillators, the wave amplitudes lie on a multidimensional sphere, reminiscent of neutrino flavor oscillations. This phenomenon has implications for cosmological scenarios based on flavor-space locked gauge fields.Comment: 4 pages, 3 figures, 1 animation; replacement matches published versio

Culture and Sustainability: An Interplay on the New Made in Italy Landscape

The current global interest and urge to propose alternatives to the predominant super-polluting and non-ethical fashion system require major attention to the unconventional fashion production models. Sustainable start-ups are often analysed as both circular systems and devices to re-activate local crafts, pointing toward not only the environmentally-friendly practices but also underlying the need to take better care of people, both as workers and consumers. However, little to no research is dedicated to the assessment of the holistic approach to sustainability of these born-responsible fashion entities. The analysis adopts the Earth Logic Fashion Action Research Plan (2019) framework by Kate Fletcher and Mathilda Tham and critically examines 60 born-sustainable brands in the Italian context. Through the analysis, it will be presented and discussed that born-sustainable does not imply a holistic approach, nor does it guarantee attention to the often-wrongly-separated environmental, social and cultural aspects of the sustainable agency

Simulation of Thermal Surface Waves in a Protoplanetary Disk in a Two-Dimensional Approximation

Theoretical models predict that the obscuration of stellar radiation by irregularities on the surface of a protoplanetary disk can cause self-generating waves traveling towards the star. However, this process is traditionally simulated using the 1+1D approach, the key approximations of which - vertical hydrostatic equilibrium of the disk and vertical diffusion of IR radiation - can distort the picture. This article presents a two-dimensional radiative hydrodynamic model of the evolution of an axially symmetric gas and dust disk. Within this model, but using simplified assumptions from 1+1D models, we have reproduced the spontaneous generation and propagation of thermal surface waves. The key conclusion of our work is that taking into account two-dimensional hydrodynamics and diffusion of IR radiation suppresses the spontaneous generation and development of thermal waves observed in the 1+1D approximation. The search for the possibility of the existence of surface thermal waves should be continued by studying the problem for various parameters of protoplanetary disks.Comment: Accepted for publication in Astronomy Reports (2022

Plasmon Resonance in а-С : Н Films Modified with Platinum Nanoclusters

Optical density spectra of amorphous diamond-like films of hydrogenated carbon modified with plati-num impurity (a-C : H) have been investigated. a-C : H films were prepared by the method of ion plasma magnetron co-sputtering of graphite and platinum in argon-hydrogen atmosphere. Platinum con-tent in the films was varied from 0 to 9 at. %. In the optical spectra of a-C : H films with different Pt content the peaks of resonance absorption in the range from 496 to 501 nm were found, whilst in the spec-trum of a-C : H films the absorption peak is absent. The appearance of these absorption peaks in a-C : H films is explained by resonance plasmon vibrations of free electrons in platinum nanocl usters. The average diameter of the Pt nanoclusters was estimated using electromagnetic theory of Mie, and it is ~ 5 nm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3638