On the properties and processing of polyethylene terephthalate/styrene‐butadiene rubber blend

The mixing of incompatible polymers such as polyethylene terephthalate (PET) and styrene‐butadiene rubber (SBR) produces a blend with poor mechanical and impact properties, because polymeric phases interact weakly with each other and segregate. The use of SBR grafted with maleic anhydride (MAH) increases the compatibility of the SBR‐PET system by generating higher interactions and chemical links between the ingredients of the blend. The induced compatibility is reflected in the 2.5‐fold increase in the impact resistance of the blend as compared to that of pure PET. The grafting reaction to produce SBR‐g‐MAH is carried out by reactive extrusion using a reaction initiator, benzoyl peroxide (BPO), and the extent of the reaction depends on the concentration of MAH and BPO. Results indicate the close relationship between processing conditions and microstructural parameters, such as particle diameter and interparticle distances of the dispersed rubber phase, necessary to achieve the optimum impact resistance.     

Production of safflower protein isolates: Composition,yield and protein quality

The use of laboratory- and commercially-prepared safflower meal for the production of protein isolates is described. The isolates were obtained by micellisation and isoelectric precipitation techniques, the latter being the most efficient procedure. Previous treatments received by the meal, for example heating, influenced the protein recovery. In general, isolates produced by micellisation were more soluble than samples obtained by isoelectric precipitation. The colour of the protein isolates depended on the isolation technique and type of safflower meal utilised. All isolates had a similar amino acid composition and levels of in-vitro protein digestibility.     

Hand movement recognition based on biosignal analysis

This paper proposes a methodology that analyses and classifies the electromyographic (EMG) signals using neural networks to control multifunction prostheses. The control of these prostheses can be made using myoelectric signals taken from surface electrodes. Finger motions discrimination is the key problem in this study. Thus the emphasis, in the proposed work, is put on myoelectric signal processing approaches. The EMG signals classification system was established using the linear neural network. The experimental results show a promising performance in classification of motions based on biosignal patterns.     

Staggered heat sinks with aerodynamic cooling fins

The effect of aerodynamic shaping of the cooling fins in staggered heat sinks is numerically studied. It is shown that by rounding the cooling fins, the aerodynamic efficiency is increased without affecting the thermal efficiency. Three different geometries (in-line rectangular, staggered rectangular and rounded staggered shape) have been compared. These three different layouts were studied to obtain the best ratio between the removed heat and the energy spent to drive the coolant flow through the cooling fins. The main purpose of the paper is to determine the influence of the rounded shape on the average performance. As an example, it was found that a rounded staggered fin layout removes the same heat for an incident air velocity of 4 m/s as a classical in-line fin layout with a higher air speed of 6 m/s, with a reduction of fan power consumption by more than 60%.     

Stress relaxation tests in polypropylene monofilament meshes used in the repair of abdominal walls

The objective of this work has been to characterize stress relaxation in the polymer material on applying different levels of constant strain. The meshes were strained at values of 5.2%, 5.4% and 5.6% which are the values at which the mesh is strained in clinical use for the repair of abdominal walls. Laws have been obtained to model the viscoelastic behavior at different strains for this material. Finally, fracture studies were carried out by environmental scanning electron microscopy to determine the fracture mechanisms of these meshes. Besides, the implantation of the meshes was practised in two different layers of abdominal wall: the superficial or preaponeurotic layer and deep or preperitoneal layer, showing the neoformation of connective tissue on the mesh, which tended to be organized differently in each layer studied; more roughly and densely in the superficial layer than in the deep one.     

Properties of Portland Cement Pastes Incorporating Nanometer-Sized Franklinite Particles Obtained from Electric-Arc-Furnace Dust

The present work presents preliminary results concerning ordinary portland cement (OPC) blended with electric-arc-furnace dust (EAFD) obtained from steel-smelting plants. The powder obtained after acid treatment of the EAFD consisted basically of nanometer-sized particles of ZnFe₂O₄. Incorporation of the EAFD in the OPC produced retardation of the setting process. Nevertheless, after 7 d, the compressive strength of the OPC/EAFD pastes was superior to undoped OPC, and, after 28 d, the extent of hydration of the OPC/EAFD pastes was equivalent to undoped OPC. A compressive strength of 72 MPa was attained after 42 d for OPC doped with 10 wt% EAFD.     

Effect of biodiesel fuels on diesel engine emissions

The call for the use of biofuels which is being made by most governments following international energy policies is presently finding some resistance from car and components manufacturing companies, private users and local administrations. This opposition makes it more difficult to reach the targets of increased shares of use of biofuels in internal combustion engines. One of the reasons for this resistance is a certain lack of knowledge about the effect of biofuels on engine emissions. This paper collects and analyzes the body of work written mainly in scientific journals about diesel engine emissions when using biodiesel fuels as opposed to conventional diesel fuels. Since the basis for comparison is to maintain engine performance, the first section is dedicated to the effect of biodiesel fuel on engine power, fuel consumption and thermal efficiency. The highest consensus lies in an increase in fuel consumption in approximate proportion to the loss of heating value. In the subsequent sections, the engine emissions from biodiesel and diesel fuels are compared, paying special attention to the most concerning emissions: nitric oxides and particulate matter, the latter not only in mass and composition but also in size distributions. In this case the highest consensus was found in the sharp reduction in particulate emissions.     

Characterization of Two Ti-Nb-Hf-Zr Alloys Under Different Cold Rolling Conditions

The objective of this study is to obtain a new biomaterial to use in the load transfer medical implants field. The influence of cold work in the thermoelastic martensitic transformation and elastic modulus was investigated for a previously developed Ti-24.8Nb-16.2Hf-1Zr alloy (A1) and a new Ti-35Nb-9Hf-1Zr alloy (A2). The nanoindentation tests with spherical tip showed a decrease of the elastic modulus when increasing the cold work percentage. The lowest value (46 GPa) was achieved after the 95% reduction in thickness for A1. By contrast, the A2 alloy exhibits its lowest elastic modulus in the uncold-worked condition (58 GPa) and did not present evidences of thermoelastic martensitic transformation.     

Effect of miscibility on mechanical and thermal properties of poly(lactic acid)/ polycaprolactone blends

Binary blends based on poly(lactic acid) (PLA) and polycaprolactone (PCL) were prepared by melt mixing in a twin‐screw co‐rotating extruder in order to increase the low intrinsic elongation at break of PLA for packaging applications. Although PLA and PCL show low miscibility, the presence of PCL leads to a marked improvement in the ductile properties of PLA. Various mechanical properties were evaluated in terms of PCL content up to 30 wt% PCL. In addition to tensile and flexural properties, Poisson's ratio was obtained using biaxial extensometry to evaluate transversal deformations when axial loads are applied. Very slight changes in the melt temperature and glass transition temperature of PLA are observed thus indicating the low miscibility of the PLA–PCL system. Field emission scanning electron microscopy reveals some interactions between the two components of the blend since the morphology is characterized by non‐spherical polycaprolactone drops dispersed into the PLA matrix. In addition to the improvement of mechanical ductile properties, PCL provides higher degradation rates of blends under conditions of composting for contents below 22.5% PCL. © 2016 Society of Chemical Industry     

Hard‐to‐cook phenomenon in common beans — A review

Legumes are one of the world's most important sources of food supply, especially in developing countries, in terms of food energy as well as nutrients. Common beans are a good source of proteins, vitamins (thiamine, riboflavin, niacin, vitamin B₆) and certain minerals (Ca, Fe, Cu, Zn, P, K, and Mg). They are an excellent source of complex carbohydrates and polyunsaturated free fatty acids (linoleic, linolenic). However, common beans have several undesirable attributes, such as long cooking times, being enzyme inhibitors, phytates, flatus factors, and phenolic compounds, having a “beany” flavor, and being lectins and allergens, which should be removed or eliminated for effective utilization.

Grain quality of common beans is determined by factors such as acceptability by the consumer, soaking characteristics, cooking quality, and nutritive value. Acceptability characteristics include a wide variety of attributes, such as grain size, shape, color, appearance, stability under storage conditions, cooking properties, quality of the product obtained, and flavor.

Storage of common beans under adverse conditions of high temperature and high humidity renders them susceptible to a hardening phenomenon, also known as the hard‐to‐cook (HTC) defect. Beans with this defect are characterized by extended cooking times for cotyledon softening, are less acceptable to the consumer, and are of lower nutritive value. Mechanisms involved in the HTC defect have not been elucidated satisfactorily. Attempts to provide a definitive explanation of this phenomenon have not been successful. The most important hypotheses that have been proposed to explain the cause of bean hardening are (1) lipid oxidation and/or polymerization, (2) formation of insoluble pectates, (3) lignification of middle lamella, and (4) multiple mechanisms. Most researchers have reported that the defect develops in the cotyledons. Recently, some authors have suggested that the seed coat plays a significant role in the process of common bean hardening. A better knowledge of cotyledon and seed coat microstructure may lead to a better understanding of the causes of seed hardness.

In order to prevent the development of the HTC defect several procedures have been proposed: (1) appropriate storage, (2) controlled atmospheres, and (3) pretreatments. Probably, the most workable solution to the hardening phenomenon may be the development of materials less prone to HTC phenomenon.

Decreasing cooking time, increasing nutritive value, and improving sensory properties of seeds with HTC defect would have great nutritional and economical impact. Furthermore, an understanding of the mechanisms leading to reversibility of this phenomenon would provide insight into the development of the defect itself and would aid in the search for appropriate methods to prevent it.

Efforts to develop technological processes are needed in order to transform the HTC beans into edible and useful products. Several economic alternatives to utilize HTC common beans have been proposed: (1) dehulling, (2) extrusion, (3) solid state fermentation, (4) quick‐cooking beans, and (5) production of protein concentrates and isolates and starch fractions.