Determining an optimal transport velocity in the marginal ice zone using operational ice-ocean prediction systems

Knowledge of transport in the marginal ice zone (MIZ) is critical for operations in the Arctic and associated emergency response applications, for example, the transport of pollutants, such as oil, as well as predicting drift associated with search and rescue operations. This paper proposes a general transport equation for the MIZ that can be used for operational purposes in the MIZ. This equation is designed to use a mean velocity of the ice and water velocity, which is weighted by the ice concentration. A key component is the introduction of a leeway coefficient for both the ocean and ice components. These leeway coefficients are determined by minimizing the velocity error between the transport model and observed drifter velocity in the MIZ. These leeway values are found to be 3 % of the wind for the water leeway and 2 % and 30° to the right of the wind for the ice leeway, which are consistent with "rule of thumb" values for surface drifters and sea ice respectively. This general transport model is compared with other transport models and the error is reduced by a factor of 2 compared with traditional transport models for 48 hour lead times. The inclusion of a leeway coefficient in the ice is the key component to reduce trajectory errors in the MIZ.

Designing Well-Organized Donor-Bridge-Acceptor Conjugated Systems Based on Cyclopentadithiophene as Donors in Bulk Heterojunction Organic Solar Cells: DFT-Based Modeling and Calculations

Two host materials based on CPDT as donors in bulk heterojunction organic solar cells were designed and investigated by means of DFT calculations. The first one (P-CPDTBT3) is a copolymer with D-A configuration and the second one (SM-CPDTDPP) is a D-π-A-π-D type small molecule. The investigated materials exhibited interesting structural properties with high planarity and rigidity originated from intra-molecular non-covalent interactions between the different building blocks. Thanks to their narrow band gaps, the optical absorption spectra have covered the main part of solar spectrum of interest. In addition, some general transport properties have been established. The transition density matrix (TDM) was used to get insight into the interaction of hole–electron localization and the electronic excitation processes. The photovoltaic parameters (FF, Voc) were calculated. The obtained results have been attempted to provide novel structure–property relationships for the rational design strategies of high-performance photovoltaic materials with power conversion efficiency of nearly 10%.

Holographic DC conductivity for backreacted NLED in massive gravity

In this work a holographic model with the charge current dual to a general non-linear electrodynamics (NLED) is discussed in the framework of massive gravity. Massive graviton can break the diffeomorphism invariance in the bulk and generates momentum dissipation in the dual boundary theory. The expression of DC conductivities in a finite magnetic field are obtained, with the backreaction of NLED field on the background geometry. General transport properties in various limits are presented, and then we turn to the three of specific NLED models: the conventional Maxwell electrodynamics, the Maxwell-Chern-Simons electrodynamics, and the Born-Infeld electrodynamics, to study the parameter-dependence of in-plane resistivities. Two mechanisms leading to the Mott-insulating behaviors and negative magneto-resistivities are revealed at zero temperature, and the role played by the massive gravity coupling parameters are discussed.

Effects of FUdR on gene expression in the C. elegans bacterial diet OP50

Objective Many C. elegans aging studies use the compound 5-fluro-2ʹ-deoxyuridine (FUdR) to produce a synchronous population of worms. However, the effects of FUdR on the bacterial gene expression of OP50 E. coli, the primary laboratory C. elegans food source, is not fully understood. This is particularly relevant as studies suggest that intestinal microbes can affect C. elegans physiology. Therefore, it is imperative that we understand how exposure to FUdR can affect gene expression changes in OP50 E. coli. Results An RNAseq dataset comprised of expression patterns of 2900 E. coli genes in the strain OP50, which were seeded on either nematode growth media (NGM) plates or on FUdR (50 µM) supplemented NGM plates, was analyzed. Analysis showed differential gene expression in genes involved in general transport, amino acid biosynthesis, transcription, iron transport, and antibiotic resistance. We specifically highlight metabolic enzymes in the l-histidine biosynthesis pathway as differentially expressed between NGM and FUdR exposed OP50. We conclude that OP50 exposed to FUdR results in differential expression of many genes, including those in amino acid biosynthetic pathways.

Eolian sedimentation in central European Auel dry maar from 60 to 13 ka

The climate in central Europe during the last 60 ka is characterized by rapid temperature and moisture changes and strong cold periods (Heinrich events). All these variations are preserved in sediments of marine and also some terrestrial archives. Here we present a continuous, terrestrial sediment record with almost all Greenland stadials and Heinrich events between 60 and 13 ka visible from carbonate roundness of the Eifel Laminated Sediment Archive Dust Stack-20 and CaCO3 data for central Europe. The carbonate roundness data show almost all stadials between 60 and 13 ka. CaCO3 data show a general transport system change with the beginning of Heinrich event 3. Since there are no carbonates west of the Auel Maar, we conclude that the eolian-transported grains were not transported by westerly but easterly winds. These postulated easterly winds during the last glacial maximum are supported by similar findings of previous works.

Mixed Delivery and Pickup Vehicle Routing Problem With Limited Flow and Assignment of Drones in an Urban Network

A new variant of the delivery and pickup transportation problem called mixed delivery and pickup routing problem with unmanned aerial vehicles in case of limited flow is introduced. The objective is to minimize operational costs including total transportation costs and service time at each point. This variant is a solution for the urban congestion, and consequently, it is an improvement of the general transport system. First, the problem is formulated mathematically. It is considered as NP-hard; therefore, the authors proposed an iterated local search algorithm to solve the problem of mixed pickup and delivery without drone. Then, a vehicle first-drone second algorithm is used to solve the mixed delivery and pickup problem with drone. The performance of the method is compared through numerical experiments based on instance derived from the literature as well as on a set of randomly generated instances. Numerical results have shown that proposed metaheuristic method performs consistently well in terms of both the quality of the solution and the computational time when using drone with vehicle.

DETERMINATION OF RUT DEPTH AND RUTING POWER WHEN ROLLING WHEELS ON DEFORMABLE GROUND

Wheeled tractors and wheeled earth-moving machines are widely used in road construction, in municipal services. The group of wheeled vehicles, numerous and varied in purpose and design, are general transport vehicles used for the transportation of various types of bulk cargo, and specialized vehicles designed to perform narrow target functions. A characteristic feature of these types of wheeled vehicles is their ability to work not only on roads with asphalt-concrete pavement, but also on deformable soil surfaces. When the wheels roll on the ground, the power consumption required to ensure the movement of the wheeled vehicle increases sharply, questions arise related to the passability of the vehicles, their controllability, and the loads in the transmission. In this regard, it becomes necessary to consider various aspects of the movement of machines in these conditions, in particular, the determination of the power spent on rutting and the depth of the track, which is what this study is devoted to. The use of the “stamp wheel” model in this work made it possible to obtain relatively simple dependencies that make it possible to calculate the track depth and the power spent on rolling both a single wheel on deformable soil, and during the sequential passage of the wheels with an expansion of the track, when the next wheel does not move. in the next ", ie exactly along the track laid by the first wheel, and with some lateral displacement. In this case, part of the wheel moves along the laid track, and the other part expands the track, compacting the previously non-deformable soil. The results of calculations using the derived formulas are in good agreement with the experimental data, which indicates the practical applicability of the obtained dependences.