Thermal conductance and thermoelectric figure of merit of C60_{60}-based single-molecule junctions: electrons, phonons, and photons

Motivated by recent experiments, we present here an ab initio study of the impact of the phonon transport on the thermal conductance and thermoelectric figure of merit of C$_{60}$-based single-molecule junctions. To be precise, we combine density functional theory with nonequilibrium Green's function techniques to compute these two quantities in junctions with either a C$_{60}$ monomer or a C$_{60}$ dimer connected to gold electrodes, taking into account the contributions of both electrons and phonons. Our results show that for C$_{60}$ monomer junctions phonon transport plays a minor role in the thermal conductance and, in turn, in the figure of merit, which can reach relatively high values on the order of 0.1, depending on the contact geometry. At the contrary, phonons completely dominate the thermal conductance in C$_{60}$ dimer junctions and strongly reduce the figure of merit as compared to monomer junctions. Thus, claims that by stacking C$_{60}$ molecules one could achieve high thermoelectric performance, which have been made without considering the phonon contribution, are not justified. Moreover, we analyze the relevance of near-field thermal radiation for the figure of merit of these junctions within the framework of fluctuational electrodynamics. We conclude that photon tunneling can be another detrimental factor for the thermoelectric performance, which has been overlooked so far in the field of molecular electronics. Our study illustrates the crucial roles that phonon transport and photon tunneling can play when critically assessing the performance of molecular junctions as potential nanoscale thermoelectric devices

Developing Multicompartment Biopolymer Hydrogel Beads for Tandem Chemoenzymatic One-Pot Process

Pauly J, Gröger H, Patel A. Developing Multicompartment Biopolymer Hydrogel Beads for Tandem Chemoenzymatic One-Pot Process. Catalysts. 2019;9(6): 547.Chemoenzymatic processes have been gaining interest to implement sustainable reaction steps or even create new synthetic routes. In this study, we combined Grubbs' second-generation catalyst with pig liver esterase and conducted a chemoenzymatic one-pot process in a tandem mode. To address sustainability, we encapsulated the catalysts in biopolymer hydrogel beads and conducted the reaction cascade in an aqueous medium. Unfortunately, conducting the process in tandem led to increased side product formation. We then created core-shell beads with catalysts located in different compartments, which notably enhanced the selectivity towards the desired product compared to homogeneously distributing both catalysts within the matrix. Finally, we designed a specific large-sized bead with a diameter of 13.5 mm to increase the diffusion route of the Grubbs' catalyst-containing shell. This design forced the ring-closing metathesis to occur first before the substrate could diffuse into the pig liver esterase-containing core, thus enhancing the selectivity to 75%. This study contributes to addressing reaction-related issues by designing specific immobilisates for chemoenzymatic processes

Design of a combined emergency fire truck of the RZA/VEA type on a uniform chassis of the Army of the Czech Republic

Předmětem této práce je vytvoření návrhu kombinovaného zásahového požárního automobilu druhu rychlý zásahový automobil a velitelský automobil na jednotném podvozku Armády České republiky pro vojenskou hasičskou jednotku Armády České republiky. V teoretické části bude popsána vojenská hasičská jednotka a dále zásahové požární automobily, jejich historie, požadavky pro zástavbu a úpravu podle zákonných požadavků České republiky. Dále bude v teoretické části popsaná teorie technických prostředků použitých v návrhu rychlého zásahového automobilu. V praktické části bude zpracovaný návrh vozidla splňující podmínky pro požární techniku podle vyhlášky č. 35/2007 Sb., o technických podmínkách požární techniky a pro vojenskou techniku podle vyhlášky č. 100/2018 Sb. o technické způsobilosti a pravidelných technických prohlídkách vojenských vozidel a splnění požadovaného vybavení od vojenské hasičské jednotky. Výsledkem práce bude vytvoření návrhu kombinované zástavby vozidla, která pomůže při realizaci výsledné zástavby vozidla vyrobené do konce roku 2025.The subject of this work is the creation of a proposal for a combined emergency fire vehicle of the type rapid intervention vehicle and command vehicle on the unified chassis of the Army of the Czech Republic for the military firefighting unit of the Army of the Czech Republic. In the theoretical part, the military fire brigade and emergency fire trucks, their history, requirements for construction and modification according to the legal requirements of the Czech Republic will be described. Furthermore, the theoretical part will describe the theory of the technical means used in the design of a rapid intervention vehicle. In the practical part, the design of a vehicle meeting the conditions for fire equipment according to Decree No. 35/2007 Coll., on the technical conditions of fire equipment and for military equipment according to Decree No. 100/2018 Coll. on the technical capability and regular technical inspections of military vehicles and the fulfillment of the required equipment from the military fire department. The result of the work will be the creation of a design of a combined vehicle structure, which will help in the implementation of the resulting vehicle structure produced by the end of 2025.030 - Katedra požární ochranydobř