Designing a forwarder operation considering tolerable soil disturbance and minimum total cost

A model is developed to minimize the sum of road construction plus forwarding costs with the constraint that rut depth caused by the forwarder cannot exceed a maximum depth during the anticipated season of operation. Road spacing, forwarder trail spacing, forwarder size, forwarder load capacity, and tire inflation pressures are used as decision variables in developing the transportation plan. The total cost was minimized using the optimum road spacing approach. The model identifies whether the cumulative rut depth caused by the forwarder exceeds the maximum allowable rut depth at the point of or prior to the spacing that minimizes the cost, and if so, the rut depth limits the road spacing. If the road spacing at the point of minimum cost is less than the road spacing at the maximum allowable rut depth, road spacing is not constrained by rut depth. This model will help logging managers to evaluate the trade-offs between specified decision variables and then to design an optimum forwarder operation with tolerable soil disturbance and minimum total cost. The solution procedure of the model is described and a computer program is used to apply this model using a numerical example.     

Preparation and Application of a Hydrochar-Based Palladium Nanocatalyst for the Reduction of Nitroarenes

In the present study, a novel heterogeneous catalyst was successfully fabricated through the decoration of palladium nanoparticles on the surface of designed Fe₃O₄-coffee waste composite (Pd-Fe₃O₄-CWH) for the catalytic reduction of nitroarenes. Various characterization techniques such as XRD, FE-SEM and EDS were used to establish its nano-sized chemical structure. It was determined that Pd-Fe₃O₄-CWH is a useful nanocatalyst, which can efficiently reduce various nitroarenes, including 4-nitrobenzoic acid (4-NBA), 4-nitroaniline (4-NA), 4-nitro-o-phenylenediamine (4-NPD), 2-nitroaniline (2-NA) and 3-nitroanisole (3-NAS), using NaBH₄ in aqueous media and ambient conditions. Catalytic reactions were monitored with the help of high-performance liquid chromatography. Additionally, Pd-Fe₃O₄-CWH was proved to be a reusable catalyst by maintaining its catalytic activity through six successive runs. Moreover, the nanocatalyst displayed a superior catalytic performance compared to other catalysts by providing a shorter reaction time to complete the reduction in nitroarenes.     

A new approach to solar flare prediction

Frontiers of Physics - Graphene oxide (GO), the functionalized graphene with oxygenated groups (mainly epoxy and hydroxyl), has attracted resurgent interests in the past decade owing to its large...     

Thermal boundary layer and the characteristic length on natural convection over a horizontal plate

Thickness of the thermal boundary layer on natural convection from a horizontal plate was experimentally measured and expressed as a function of Rayleigh number both in laminar and turbulent regimes. Several parametric equations expressing the Nusselt number as a function of Rayleigh number were developed combining experimental data by other authors with the ones obtained in this work. The characteristic length was taken as the thickness of the thermal boundary layer in one equation and as the ratio of the area to the perimeter in another one. Both characteristic lengths correlated the data precisely in wide ranges of Rayleigh numbers.

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Stability and coherence of strong-coupling magneto-bipolaron in asymmetric quantum dot under laser field effect

On the fundamental basis of the modified Lee Low Pines theoretical method, we study analytically the stability and coherence of magneto-bipolaron in asymmetric quantum dot (QD) under the laser field. It is observed that, the bipolaron stability strongly depends on the electron–phonon coupling constant, magnetic field, laser frequency and high laser field strength. It is shown that, the laser field can trap and cool the magneto-bipolaron under certain conditions. The laser and magnetic field strongly affect the coherence time of bipolaron. This study enables to construct superconducting materials.     

Determination of electrical parameters of ZnO/Si heterojunction device fabricated by RF magnetron sputtering

Optical and Quantum Electronics - A single mode condition for silica–titania rib waveguides is proposed in this work. It is applicable to rib waveguides having rib height sufficiently small...     

Parallel Implementation of Synchronous Type Artificial Bee Colony Algorithm for Global Optimization

Evolutionary algorithms often need huge running times when solving large-scale optimization problems. One of the solutions for this issue is to introduce parallelization into the algorithm. To benefit from this approach for the artificial bee colony optimization algorithm, we present a new synchronous and parallel version of the algorithm. Performances of the proposed version and the original asynchronous algorithm are compared in terms of efficiency and speedup. Algorithms are competed to solve 20 large-scale global optimization problems. Comparative results show that the proposed parallel algorithm is still efficient as asynchronous version while it requires much less time to solve complex and large problems.     

Light-activated hydrogel formation via the triggered folding and self-assembly of a designed peptide

Photopolymerization can be used to construct materials with precise temporal and spatial resolution. Applications such as tissue engineering, drug delivery, the fabrication of microfluidic devices and the preparation of high-density cell arrays employ hydrogel materials that are often prepared by this technique. Current photopolymerization strategies used to prepare hydrogels employ photoinitiators, many of which are cytotoxic and require large macromolecular precursors that need to be functionalized with moieties capable of undergoing radical cross-linking reactions. We have developed a simple light-activated hydrogelation system that employs a designed peptide whose ability to self-assemble into hydrogel material is dependent on its intramolecular folded conformational state. An iterative design strategy afforded MAX7CNB, a photocaged peptide that, when dissolved in aqueous medium, remains unfolded and unable to self-assemble; a 2 wt % solution of freely soluble unfolded peptide is stable to ambient light and has the viscosity of water. Irradiation of the solution (260 < lambda < 360 nm) releases the photocage and triggers peptide folding to produce amphiphilic beta-hairpins that self-assemble into viscoelastic hydrogel material. Circular dichroic (CD) spectroscopy supports this folding and self-assembly mechanism, and oscillatory rheology shows that the resulting hydrogel is mechanically rigid (G' = 1000 Pa). Laser scanning confocal microscopy imaging of NIH 3T3 fibroblasts seeded onto the gel indicates that the gel surface is noncytotoxic, conducive to cell adhesion, and allows cell migration. Lastly, thymidine incorporation assays show that cells seeded onto decaged hydrogel proliferate at a rate equivalent to cells seeded onto a tissue culture-treated polystyrene control surface.