Oxidative Precipitation of Manganese from Dilute Waters

Various metals may be removed from mine water by precipitation of their hydroxides. However, over the pH range of 7–9, it is more efficient to oxidize Mn II to Mn IV than to precipitate Mn II as its hydroxide. Chlorine (or hypochlorite) can be used to do this, but its use may not be appropriate for mine waters that will be recycled as process solutions or discharged into a receiving body. Consequently, there has been interest in reducing chlorine use or its total replacement by non-chlorinated oxidants, such as oxygen and peroxygens, for treatment of mine water. In this work, we report the results of a comparative investigation of the following oxidants: NaClO (as reference), O₂; H₂O₂; Caro’s acid (H₂SO₅), and the combination of H₂O₂ with NaClO, with initial [Mn] = 10 mg/L, at 25 °C, with 100 and 300 % excess oxidant above the stoichiometric requirement. It was found that the reaction pH has to be greater than 8 to obtain effective precipitation. It is possible to reach a final [Mn] below 1.0 mg/L in 60 min of batch reaction time, using either NaClO, Caro’s Acid, or a combination of NaClO + H₂O₂. Using only O₂ or H₂O₂ was ineffective.     

Analysis of the influence of composition and processing parameters on the mechanical properties of biodegradable starch/pectin blends

The selection of the composition and processing conditions for carbohydrate-based blends is of fundamental importance for many applications and plays a role in determining the mechanical behavior of these biodegradable materials. In this study, starch/pectin (PEC) blends were obtained via melt technique and an investigation of the effects of composition and processing parameters on their mechanical properties was performed. The blends were prepared by adopting an experimental design and were characterized by uniaxial tensile tests, scanning electron microscopy, and phase imaging atomic force microscopy. The starch:PEC mass ratio showed the maximum influence on the tensile properties, which were independent on the processing parameters. It was suggested that as the degree of methyl esterification of PEC decreased, the modulus and tensile strength of the blends increased, and this effect was observed up to 50?wt% starch. AFM revealed the immiscibility between the polymers and this phenomenon was associated to the mechanical behavior of the blends.     

Fixed-sized representation learning from offline handwritten signatures of different sizes

Methods for learning feature representations for offline handwritten signature verification have been successfully proposed in recent literature, using deep convolutional neural networks to learn representations from signature pixels. Such methods reported large performance improvements compared to handcrafted feature extractors. However, they also introduced an important constraint: the inputs to the neural networks must have a fixed size, while signatures vary significantly in size between different users. In this paper, we propose addressing this issue by learning a fixed-sized representation from variable-sized signatures by modifying the network architecture, using spatial pyramid pooling. We also investigate the impact of the resolution of the images used for training and the impact of adapting (fine-tuning) the representations to new operating conditions (different acquisition protocols, such as writing instruments and scan resolution). On the GPDS dataset, we achieve results comparable with the state of the art, while removing the constraint of having a maximum size for the signatures to be processed. We also show that using higher resolutions (300 or 600 dpi) can improve performance when skilled forgeries from a subset of users are available for feature learning, but lower resolutions (around 100dpi) can be used if only genuine signatures are used. Lastly, we show that fine-tuning can improve performance when the operating conditions change.     

A note on supply chain risk classification: discussion and proposal

The main objective of this note is to complement the excellent work on supply chain risk classification by Rangel et al. [International Journal of Production Research, vol. 52 (7), 2014]. In this note, we consider the use of ISO/IEC (International Organisation for Standardisation/International Electrotechnical Commission) norms to support the supply chain risk classification. Its purpose is to develop, maintain and promote standards in the fields of information technology and information communications technology. Therefore, to improve on the work by Rangel et al. (2014), ISO 27036 (Information Security for Supplier Relationship) and ISO 28000 (Specification for Security Management Systems for the Supply Chain) are aligned with ISO 31000 (Risk Management–Risk Assessment Techniques). Furthermore, since supply chain risk management does not have a standardised process, these norms, particularly ISO 31000, can serve as a guide to improve its implementation.     

Hybrid evolutionary algorithm for the Capacitated Centered Clustering Problem

The Capacitated Centered Clustering Problem (CCCP) consists of defining a set of p groups with minimum dissimilarity on a network with n points. Demand values are associated with each point and each group has a demand capacity. The problem is well known to be NP-hard and has many practical applications. In this paper, the hybrid method Clustering Search (CS) is implemented to solve the CCCP. This method identifies promising regions of the search space by generating solutions with a metaheuristic, such as Genetic Algorithm, and clustering them into clusters that are then explored further with local search heuristics. Computational results considering instances available in the literature are presented to demonstrate the efficacy of CS.     

Shear strength parallel to grain with distinct ray orientation on four Brazilian wood species

Ray orientation (perpendicular, parallel and diagonal) was compared with respect to shear strength parallel to grain and specific gravity in four Brazilian wood species. Higher absolute strengths occurred with ray oriented perpendicular to the shear plane, and lower ones for parallel orientation for almost all species. In particular, specimens with parallel ray orientation to shear plane did not differ statistically from shear values when compared to specimens having perpendicular and diagonal orientation to shear plane.     

The air temperature modulation impact on the drying of soybeans in a fixed bed

This work aimed to explore an alternative to reduce costs in the soybean drying process using a periodic drying operation, which can enhance mass and energy transfer, leading to lower energy consumption in comparison with the conventional operation carried out with entrance drying air in steady-state conditions. A fixed bed dryer for laboratory scale was used to dry soybean grains and experiments were carried out, applying the periodic and conventional operations with the same drying time and energy consumption. Results indicated with 5% of significance that the experiments conducted with entrance air temperature modulation achieved higher levels of the percentage of evaporated water improving the dryer performance. These results were in agreement with predicted data obtained with heterogeneous models and they indicated that the periodic drying operation can demand less energy to achieve a specific safe level of soybean moisture content for storage.     

Protein quality of dried enzymatic hydrolysate from anchovy produced in a spouted bed of inert particles

The anchovy (Engraulis anchoita) is a pelagic fish and due to its abundance in South America shows a sustainable exploitation. The enzymatic hydrolysis of anchovy protein associated to the drying technique in spouted bed was analysed in order to obtain products with the best characteristics. The drying conditions were inlet air temperature, concentration and flow rate of suspension. The degree of hydrolysis of the anchovy suspension was of 3.8%, and its available lysine and specific antioxidant activity were of 86 g kg^?1_protein and 4.31 mm _DPPH kg^?1 min^?1, respectively. In spouted bed drying, the lowest reduction in available lysine (9%) and loss of specific antioxidant activity (8%) were found at 90 °C, and suspension concentration and flow rate of 65 g L^?1 and 200 mL h^?1, respectively. The dried product was characterised as a protein source of high biological value due to the essential amino acids profile.