Finite size corrections to the blackbody radiation laws

We investigate the radiation of a blackbody in a cavity of finite size. For a given geometry, we use semiclassical techniques to obtain explicit expressions of the modified Planck's and Stefan-Boltzmann's blackbody radiation laws as a function of the size and shape of the cavity. We determine the range of parameters (temperature, size and shape of the cavity) for which these effects are accessible to experimental verification. Finally we discuss potential applications of our findings in the physics of the cosmic microwave background and sonoluminescence.Comment: 5 pages, 1 figure, journal versio

Comparative energetic assessment of methanol production from CO₂: chemical versus electrochemical process

Emerging emission-to-liquid (eTL) technologies that produce liquid fuels from CO₂ are a possible solution for both the global issues of greenhouse gas emissions and fossil fuel depletion. Among those technologies, CO₂ hydrogenation and high-temperature CO₂ electrolysis are two promising options suitable for large-scale applications. In this study, two CO₂ -to-methanol conversion processes, i.e., production of methanol by CO₂ hydrogenation and production of methanol based on high-temperature CO₂ electrolysis, are simulated using Aspen HYSYS. With Aspen Energy Analyzer, heat exchanger networks are optimized and minimal energy requirements are determined for the two different processes. The two processes are compared in terms of energy requirement and climate impact. It is found that the methanol production based on CO₂ electrolysis has an energy efficiency of 41%, almost double that of the CO₂ hydrogenation process provided that the required hydrogen is sourced from water electrolysis. The hydrogenation process produces more CO₂ when fossil fuel energy sources are used, but can result in more negative CO₂ emissions with renewable energies. The study reveals that both of the eTL processes can outperform the conventional fossil-fuel-based methanol production process in climate impacts as long as the renewable energy sources are implemented

A note on static dyonic diholes

In this brief note we argue that a dyonic generalization of the Emparan-Teo dihole solution is described by a static diagonal metric and therefore, contrary to the claim made in a recent paper by Cabrera-Munguia et al., does not involve any "non-vanishing global angular momentum" and rotating charges.Comment: 4 pages, 1 figure; typos corrected, matches the published versio

Electroproduction ratios of Baryon-Meson states and Strangeness Suppression

We describe the electroproduction ratios of baryon-meson states from nucleon, inferring from the sea quarks in the nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states:$\Lambda K^+$, $\Sigma ^{*}K$, $\Sigma K$, $p\pi^0$, and $n\pi^+$. These predictions are in agreement with the new Jlab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial test of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we computed the so called strangeness suppression factor, $\lambda_s$, that is the suppression of strange quark-antiquarks compared to nonstrange pairs, and we found that our finding with this simple extension of the quark model is in good agreement with the results of Jlab and CERN experiments.Comment: 4 pages, 1figur