Concept design of a fast sail assisted feeder container ship

An environmentally sustainable fast sail-assisted feeder-container ship concept, with a maximum speed of 25 knots, has been developed for the 2020 South East Asian and Caribbean container markets. The use of low-carbon and zero-sulphur fuel (liquefied natural gas) and improvements in operational efficiency (cargo handling and scheduling) mean predicted Green house gas emissions should fall by 42% and 40% in the two selected operational regions. The adoption of a Multi-wing sail system reduces power requirement by up to 6% at the lower ship speed of 15 knots. The predicted daily cost savings are respectively 27% and 33% in South East Asian and the Caribbean regions.Two hull forms with a cargo capacity of 1270TEU utilising different propulsion combinations were initially developed to meet operational requirements. Analysis & tank testing of different hydrodynamic phenomena has enabled identification of efficiency gains for each design. The final propulsion chosen is a contra-rotating podded drive arrangement. Wind tunnel testing improved Multi-wing sail performance by investigating wing spacing, wing stagger and sail-container interactions. The associated lift coefficient was increased by 32%. Whilst savings in sail-assisted power requirement are lower than initially predicted an unexpected identified benefit was motion damping.The fast feeder-container ship is a proposed as a viable future method of container transhipment

Target annihilation by diffusing particles in inhomogeneous geometries

The survival probability of immobile targets, annihilated by a population of random walkers on inhomogeneous discrete structures, such as disordered solids, glasses, fractals, polymer networks and gels, is analytically investigated. It is shown that, while it cannot in general be related to the number of distinct visited points, as in the case of homogeneous lattices, in the case of bounded coordination numbers its asymptotic behaviour at large times can still be expressed in terms of the spectral dimension $\widetilde {d}$, and its exact analytical expression is given. The results show that the asymptotic survival probability is site independent on recurrent structures ($\widetilde{d}\leq2$), while on transient structures ($\widetilde{d}>2$) it can strongly depend on the target position, and such a dependence is explicitly calculated.Comment: To appear in Physical Review E - Rapid Communication

Intranasal ciclesonide for allergic rhinitis

Ciclesonide is a novel corticosteroid which is optimized for topical use. It is a pro-drug which is activated locally in the airway mucosa, lipid-conjugated for local retention, and has very high protein binding in circulation leading to low systemic bioavailability. These characteristics should lead to highly selective activity with reduced local and systemic side effects. It has been established as an inhaled medication for asthma and has also been shown in double-blind trials to be efficacious for the treatment of seasonal and perennial allergic rhinitis. However no data have yet demonstrated superiority over existing nasal topical corticosteroids, either in terms of efficacy or adverse effects, and trials have not yet clearly shown efficacy in rhinitis in children. Therefore the place of ciclesonide in the treatment of allergic rhinitis relative to other existing products remains unclear

Cis/trans energetics in epoxide, thiirane, aziridine and phosphirane containing cyclopentanols: Effects of intramolecular OH···O,S,N and P contacts

c 2019 by the authors A recent computational analysis of the stabilizing intramolecular OH···O contact in 1,2-dialkyl-2,3-epoxycyclopentanol diastereomers has been extended to thiiriane, aziridine and phosphirane analogues. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and CCSD(T) coupled-cluster computations with simple methyl and ethyl substituents indicate that electronic energies of the cis isomers are lowered by roughly 3 to 4 kcal mol−1 when the OH group of these cyclopentanol systems forms an intramolecular contact with the O, S, N or P atom on the adjacent carbon. The results also suggest that S and P can participate in these stabilizing intramolecular interactions as effectively as O and N in constrained molecular environments. The stabilizing intramolecular OH···O, OH···S, OH···N and OH···P contacts also increase the covalent OH bond length and significantly decrease the OH stretching vibrational frequency in every system with shifts typically on the order of −41 cm−

Lubricating Bacteria Model for Branching growth of Bacterial Colonies

Various bacterial strains (e.g. strains belonging to the genera Bacillus, Paenibacillus, Serratia and Salmonella) exhibit colonial branching patterns during growth on poor semi-solid substrates. These patterns reflect the bacterial cooperative self-organization. Central part of the cooperation is the collective formation of lubricant on top of the agar which enables the bacteria to swim. Hence it provides the colony means to advance towards the food. One method of modeling the colonial development is via coupled reaction-diffusion equations which describe the time evolution of the bacterial density and the concentrations of the relevant chemical fields. This idea has been pursued by a number of groups. Here we present an additional model which specifically includes an evolution equation for the lubricant excreted by the bacteria. We show that when the diffusion of the fluid is governed by nonlinear diffusion coefficient branching patterns evolves. We study the effect of the rates of emission and decomposition of the lubricant fluid on the observed patterns. The results are compared with experimental observations. We also include fields of chemotactic agents and food chemotaxis and conclude that these features are needed in order to explain the observations.Comment: 1 latex file, 16 jpeg files, submitted to Phys. Rev.

Non-linear evolution of cosmological structures in warm dark matter models

The dark energy dominated warm dark matter (WDM) model is a promising alternative cosmological scenario. We explore large-scale structure formation in this paradigm. We do this in two different ways: with the halo model approach and with the help of an ensemble of high-resolution N-body simulations. Combining these quasi-independent approaches leads to a physical understanding of the important processes which shape the formation of structures. We take a detailed look at the halo mass function, the concentrations and the linear halo bias of WDM. In all cases we find interesting deviations with respect to cold dark matter (CDM). In particular, the concentration-mass relation displays a turnover for group scale dark matter haloes, for the case of WDM particles with masses of the order of mWDM∼ 0.25 keV. This may be interpreted as a hint for top-down structure formation on small scales. We implement our results into the halo model and find much better agreement with simulations. On small scales, the WDM halo model now performs as well as its CDM counterpar

Biological Channeling of a Reactive Intermediate in the Bifunctional Enzyme DmpFG

It has been hypothesized that the bifunctional enzyme DmpFG channels its intermediate, acetaldehyde, from one active site to the next using a buried intermolecular channel identified in the crystal structure. This channel appears to switch between an open and a closed conformation depending on whether the coenzyme NAD(+) is present or absent. Here, we applied molecular dynamics and metadynamics to investigate channeling within DmpFG in both the presence and absence of NAD(+). We found that substrate channeling within this enzyme is energetically feasible in the presence of NAD(+) but was less likely in its absence. Tyr-291, a proposed control point at the channel's entry, does not appear to function as a molecular gate. Instead, it is thought to orientate the substrate 4-hydroxy-2-ketovalerate in DmpG before reaction occurs, and may function as a proton shuttle for the DmpG reaction. Three hydrophobic residues at the channel's exit appear to have an important role in controlling the entry of acetaldehyde into the DmpF active site

Biological Channeling of a Reactive Intermediate in the Bifunctional Enzyme DmpFG

AbstractIt has been hypothesized that the bifunctional enzyme DmpFG channels its intermediate, acetaldehyde, from one active site to the next using a buried intermolecular channel identified in the crystal structure. This channel appears to switch between an open and a closed conformation depending on whether the coenzyme NAD+ is present or absent. Here, we applied molecular dynamics and metadynamics to investigate channeling within DmpFG in both the presence and absence of NAD+. We found that substrate channeling within this enzyme is energetically feasible in the presence of NAD+ but was less likely in its absence. Tyr-291, a proposed control point at the channel's entry, does not appear to function as a molecular gate. Instead, it is thought to orientate the substrate 4-hydroxy-2-ketovalerate in DmpG before reaction occurs, and may function as a proton shuttle for the DmpG reaction. Three hydrophobic residues at the channel's exit appear to have an important role in controlling the entry of acetaldehyde into the DmpF active site