Electrochemical nucleation of nickel on vitreous carbon electrodes: the influence of organic additives

The initial stages of the electrodeposition of nickel onto vitreous carbon from ethanol/water chloride solutions was studied in the presence and absence of some organic compounds. The influence of both additives and metal concentration was investigated by cyclic voltammetry, potential step experiments and differential capacity measurements. The role of the additives in the deposition process related to their adsorption, both on vitreous carbon and on vitreous carbon/nickel deposited electrodes, is also discussed.     

Improvement of the mechanical and flame-retardant properties of polyetherimide membranes modified with Graphene oxide

Polyetherimide (PEI) membranes doped with different amounts (1–5 wt.%) of Graphene Oxide (GO) were prepared through a solution casting method. The effect of the Graphene Oxide incorporation on mechanical and flame-retardant properties was investigated by XDR, FTIR and SEM analyses. Results showed that the addition of 5 wt.% of GO into the membranes caused a 30% of improvement in the tensile strength and a significant increase in the glass transition temperature. Flame-retardant properties were improved when the amount of Graphene Oxide into PEI membrane was increased. These improvements in the membrane composites expand its application for aerospace and building industries.     

CO2 capture in different carbon materials

In this work, the CO(2) capture capacity of different types of carbon nanofibers (platelet, fishbone, and ribbon) and amorphous carbon have been measured at 26 °C as at different pressures. The results showed that the more graphitic carbon materials adsorbed less CO(2) than more amorphous materials. Then, the aim was to improve the CO(2) adsorption capacity of the carbon materials by increasing the porosity during the chemical activation process. After chemical activation process, the amorphous carbon and platelet CNFs increased the CO(2) adsorption capacity 1.6 times, whereas fishbone and ribbon CNFs increased their CO(2) adsorption capacity 1.1 and 8.2 times, respectively. This increase of CO(2) adsorption capacity after chemical activation was due to an increase of BET surface area and pore volume in all carbon materials. Finally, the CO(2) adsorption isotherms showed that activated amorphous carbon exhibited the best CO(2) capture capacity with 72.0 wt % of CO(2) at 26 °C and 8 bar.     

Quality changes in chilled Norway lobster (Nephrops norvegicus) tail meat and the effects of delayed icing

The quality deterioration of Norway lobster (Nephrops norvegicus) tail meat was monitored during ice storage. The K‐value started at 0.7% and reached a value of 39.7% on day 14. Muscle pH followed a sigmoidal pattern that reached a plateau on day 6. Bacterial load and trimethylamine (TMA) increased only after a lag phase to reach considerable levels by day 14 (5.3 log cfu and 10.2 mg (100 g)^?1, respectively). These analytical data were compared with sensory data. Principal component analysis (PCA) indicated that laboratory measures were correlated positively with the smell strength of cooked product (increasingly strong) and negatively with the smell character of raw and cooked product (sour‐ammoniacal in raw and neutral in cooked products), flavour and aftertaste (both increasingly bland–bitter). The effects of icing delays on the quality of tail meat were also evaluated. Changes in K‐values, microbial load, muscle pH and TMA indicated that the delay to icing should be no more than 4 h (at 16 °C) to ensure that quality is not compromised during subsequent post‐harvest storage.     

Parallel Computation for Radiative Heat Transfer Using the DOM in Combustion Applications: Direction,Frequency, Subdomain Decompositions,and Hybrid Methods

In the framework of coupled large-eddy/discrete ordinates method (LES/DOM) computations of turbulent combustion problems, various decompositions for parallel calculations of the radiative heat transfer based on the DOM are investigated. The methods analyzed are: (A) a task decomposition on the discrete directions and frequencies with two numeric strategies: Message Passing Interface (MPI) with distributed memory and OpenMP with shared memory for the direction decomposition; (B) a new algorithm for a DOM subdomain decomposition, which is proposed and tested using MPI; and (C) hybrid methods combining an OpenMP strategy for direction and MPI for tasks and subdomain decomposition. It is shown for the case of coupled simulations that the convergence and the parallel efficiency of the domain decomposition (B) are optimal. This method is limited in this work to 25 sub-domains, at which point the efficiency stagnates. Combining the directions with frequency and/or domain decompositions in a hybrid method (C) results in very good efficiency up to 1,200 processors. This hybrid strategy is also very efficient in terms of memory usage. This work shows that the best way to perform massively parallel computation for radiative heat transfer with the DOM is to combine different decomposition levels. The analysis performed in this work shows the best parallel strategy to be used in coupled simulations between radiation and LES on massively parallel architectures.     

Electrodeposition of zinc-nickel alloy coatings: influence of a phenolic derivative

The electroplating of Zn–Ni alloy films from a chloride bath has been studied under different plating conditions, both in the absence and presence of a phenolic derivative. Under the conditions examined, the electrodeposition of the alloys belonged to the anomalous type. The morphology and composition of the deposits varied with current density, temperature, bath composition and additive concentration. The results show that the additive modifies the structure and surface topography of the deposits to a large extent and produces smoother deposits. The corrosion resistance of the alloys has been analyzed by means of salt-spray tests.     

A stochastic joint replenishment problem considering transportation and warehouse constraints with gainsharing by Shapley Value allocation

The purpose of this paper is to introduce a heuristic approach that uses a capacitated inventory model as means for identifying a collaborative agreement between different buyers jointly replenishing multiple items from multiple vendors, thus attaining economies of scale while reducing by sharing fixed procurement and operational costs. The proposed approach is denominated Stochastic Collaborative Joint Replenishment Problem (S-CJRP) and consists of two stages. The first stage determines a cost-efficient replenishment frequency for each collaborating company in all possible coalition arrangements. To accomplish the former, an extension of the known Joint Replenishment Problem (JRP) considering real-life capacity constraints, such as stochastic demand assuming normal distribution, finite storage and transport, is solved via genetic algorithms delivering a suitable coalition. In a second stage, the Shapley Value function is established to assess and allocate the potential gains achieved by colluding in the first stage, determining a fair share distribution among players that increases the viability of such coalition. Several scenarios from a simulated numerical study illustrate average cost savings of 32.3%. 28.2% and 32.7% for 3, 4 and 5 players, respectively, considering up to 30 items for the proposed collaboration, in all cases consistently exhibiting cost reduction and increasing the proposal feasibility.     

Physicochemical characterisation and in vitro Starch digestion of Avocado Seed Flour (Persea americana V. Hass) and its starch and fibrous fractions

The avocado seed is considered a by-product of their pulp exploitation and today it does not present relevant food or industrial applications. In this study, we evaluate the potential use of its flour, their isolated starch and fibre fractions. After processing, the flour yielded 46.28%, and showed 6.7% of protein and low fat and ash contents (3.4, and 2.71% respectively). The starch yielded 27.28% with low-fibre content that influenced its viscosity properties; as well as their water absorption index (WAI), water solubility index (WSI) and oil absorption index (OAI), that were 2.43%, 11.22% and 0.16% respectively. The in vitro starch digestion of the different obtained fractions showed higher amounts of rapidly digestible starch (56.8%–75.36%, flour and starch respectively). The functional properties of the materials were correlated with strong molecular interactions with their apparently unique amylose structure; for this, this by-product may have different potential for food applications.     

Boundary element study on the optical method of caustic for measuring fast crack propagation toughness K ID

The dynamic stress field near the tip of a crack tip which is accelerated and decelerated in an elastic plate with finite width under impact loading is analyzed by the boundary element method, and a simulation of measuring fast crack propagation toughness K _ID by the caustic method is performed. The results of the simulation agree qualitatively with the experimental results by Arakawa and Takahashi, and indicate the dependence of the measured K _ID not only on crack acceleration but also plate width. The dependence of measured K _ID on crack acceleration may result from the fact that under the condition of high loading rate or abrupt change in crack velocity, the transient stress field near the initial curve of caustic can not be represented fully by the dynamic stress intensity factor K _I(t, v), as suggested by Rosakis et al. The dependence of measured K _ID on plate width may be attributable to the fact that the transient stress field near the initial curve is affected directly by the reflected stess wave and also indirectly through crack acceleration which depends on the reflected stress wave. The possible dependence of the measured K _ID on loading rate, loading history, crack propagation history is also discussed.