Mechanical and Morphological Studies of Poly(propylene)‐Filled Eggshell Composites

Poly(propylene) (PP) composites were prepared by using eggshell (ES) as filler and their mechanical properties were compared with those using talc (TA) and calcium carbonate (CC) of different grain sizes (X₅₀). A decrease in impact strength and deformation at break with increase in filler content was observed. The PP composite with ES (X₅₀ = 8.4 µm) was stiffer than those with CC (X₅₀ = 0.7 µm). The hybrid composite PP‐ES‐TA showed a similar stiffness as the PP‐TA composites due to the similar morphology of TA (X₅₀ = 0.5 µm) and ES, when TA was replaced up to 75 wt.‐% by ES. SEM study revealed evidence of improved interfacial bonding between PP and ES in theirs composites.

     

Effect of food intake on protein quality measured in chicks by traditional or biochemical methods

Previous studies have shown that the activities of the hepatic enzymes xanthine dehydrogenase and nucleoside phosphorylase, as well as the uric acid excreted, can be used to determine the quality of the protein consumed in chickens, in a short time and using a small amount of the test protein. A common observation in protein quality evaluation is that the food intake of the control animals is considerably greater than that observed in those receiving proteins of low quality. Since this can affect the results, this study measured the quality of garbanzo bean and black bean proteins in chickens fed these beans ad libitum, feeding the bean diets at the level observed in the controls (soy protein+methionine) by enteral intubation or pair feeding the controls with the amount of food consumed by the chickens receiving the bean diets. In every case, protein quality was determined by protein efficiency ratio, net protein utilisation or the biochemical methods used in this study. The results showed that, when fed ad libitum, the animals assigned to the bean diets exhibited a lower food intake than the controls but, by tube feeding, food intake was made equal in both groups. Equal consumption, between these groups, was also obtained by reducing the amount of food offered to the controls to the levels measured in the groups assigned to the bean diets (pair feeding). These feeding strategies had a marked effect on growth, carcass protein content, protein catabolism and also in the results of protein quality. Thus, the control whose intake was reduced grew less, accumulated less protein in tissues and catabolised more of the protein consumed than the control fed ad libitum. In contrast, the chickens assigned to the bean diets, but whose food intake was increased by tube feeding, grew better, accumulated more protein in tissues and catabolised less protein. In general, the results of these experiments confirm the effectiveness of the biochemical methods for estimating protein quality and indicate that the protein quality of both garbanzo beans and black beans increased when it was measured at a food intake equivalent to that measured in the control animals. Since the overall purpose of this study was to evaluate techniques for protein quality determination meant to be applicable to humans nutrition rather than poultry nutrition, single proteins were used instead of combinations of proteins. © 1998 Society of Chemical Industry.     

A terrestrial biotic ligand model. 1. Development and application to Cu and Ni toxicities to barley root elongation in soils

A Terrestrial Biotic Ligand Model (TBLM) was developed using noncalcareous soils from Europe based on Cu and Ni speciation and barley (Hordeum vulgare cv. Regina) root elongation bioassays. Free metal ion (M2+) activity was computed by the WHAM VI model using inputs of soil metal, soil organic matter, and alkali and alkaline earth metals concentrations, and pH in soil solution. The TBLM assumes that metal in soil and in the solution are in equilibrium. Metal ions react with the biotic ligand, the receptor site, and inhibit root elongation. Other ions, principally H+, Ca2+ and Mg2+, compete with M2+ and, therefore, affect its toxicity. Toxicity is correlated only to the fraction of the total biotic ligand sites occupied by M2+. Compared to other models using either the soil metal concentration or M2+ activity as the toxic dose, the TBLM provides a more consistent method to normalize and compare Cu and Ni toxicities to root elongation among different soils. The TBLM was able to predictthe EC50 soil Cu and Ni concentrations generally within a factor of 2 of the observed values, a level of precision similar to that for the aquatic Biotic Ligand Model, indicating its potential utility in metals risk assessment in soils.     

Density-Functional-Theory Study of Cohesive,Structural and Electronic Properties of Ni-Sb Intermetallic Phases

This work has its roots in a long-term theoretical research line aimed at developing a complete database with structural, thermodynamic, cohesive and elastic properties of the intermetallic compounds (ICs) of the type Me_aX_b where Me = Cu, Ni and X = In, Sn and Sb. The paper reports the results of an ab initio study of various phases occurring in the Ni-Sb phase diagram, viz., the low-temperature Ni₃Sb (orthorhombic oP8), the high-temperature Ni₃Sb (cubic cF16), Ni₅Sb₂ (monoclinic mC28), NiSb (hexagonal hP4) and the NiSb₂ (orthorhombic oP6) compounds. The molar volume, bulk modulus and its pressure derivative, the electronic density of states (DOS) and the energy of formation from the elements of these compounds are calculated ab initio using the relativistic projected augmented wave (PAW) method implemented in the VASP code. The Local Density Approximation of Ceperley and Alder and the Generalized Gradient Approximation due to Perdew and Wang are adopted to treat the exchange and correlation energies. Detailed comparisons between the current and previously reported theoretical and experimental values are reported.     

The effect of fructooligosaccharides on the sensory characteristics of cooked sausages

The effect of a short chain fructooligosaccharide on the sensory properties of conventional and reduced-fat cooked meat sausages has been studied in products in which a fat reduction of close to 40% was obtained. The fibre assayed was used in sufficient amounts to constitute between 2% and 12% of the final product. The energy value reduction of the final products was close to 35%. Instrumental measurements of colour and texture were performed. Sensory properties were estimated by a hedonic test. A correlation principal component analysis was performed. The results showed that the sensory and textural properties and the overall acceptability were very good, which indicated that this fibre can be considered a good fat replacer in meat products. Thus, with its addition, a reduced calorie product enriched with soluble dietetic fibre is obtained.     

Biomolecular conjugation inside synthetic polymer nanopores via glycoprotein-lectin interactions

We demonstrate the supramolecular bioconjugation of concanavalin A (Con A) protein with glycoenzyme horseradish peroxidase (HRP) inside single nanopores, fabricated in heavy ion tracked polymer membranes. Firstly, the HRP-enzyme was covalently immobilized on the inner wall of the pores using carbodiimide coupling chemistry. The immobilized HRP-enzyme molecules bear sugar (mannose) groups available for the binding of Con A protein. Secondly, the bioconjugation of Con A on the pore wall was achieved through its biospecific interactions with the mannose residues of the HRP enzyme. The immobilization of biomolecules inside the nanopore leads to the reduction of the available area for ionic transport, and this blocking effect can be exploited to tune the conductance and selectivity of the nanopore in aqueous solution. Both cylindrical and conical nanopores were used in the experiments. The possibility of obtaining two or more conductance states (output), dictated by the degree of nanopore blocking resulted from the different biomolecules in solution (input), as well as the current rectification properties obtained with the conical nanopore, could also allow implementing information processing at the nanometre scale. Model simulations based on the transport equations further verify the feasibility of the sensing procedure that involves concepts from supramolecular chemistry, molecular imprinting, recognition, and nanotechnology.     

Degradation of an Azo Dye (Ponceau 4R) and Treatment of Wastewater from a Food Industry by Ozonation

Experiments for degradation of the extensively marketed Ponceau 4R dye in aqueous solution and for oxidation of raw wastewater from a confectionary industry have been carried out by using ozone. All the experiments were performed in a cylindrical semi-batch reactor at approximately 20 ^oC for 7200 s. A mass flow rate of 1.158?×?10^?6 kg s^?1 of ozone was continuously fed in the reactor. The pH of the azo dye aqueous solution (distilled water + Ponceau 4R) was always kept at approximately 5.8, while in the case of the raw wastewater the same factor was changed from 4.7 to 9.4 in two different experimental runs. Absorbance measurements at 508 nm show that the investigated azo dye found in the azo dye aqueous solution was completely degraded after only 600 s. At this initial period a substantial fall of TOC (Total Organic Carbon) (up to 45%) was noticed, but the rate was exponentially decreased at longer reaction times up to a TOC removal no higher than 60%. The ozonation was also responsible for reducing the apparent color of the raw wastewater to almost 10% of its initial value at the optimum pH (9.4 ± 1.5). The effect of pH was important on apparent color, but it had absolutely no influence on the kinetics results of COD (Chemical Oxygen Demand), which were kept constant over the entire period of reaction.     

Oily Wastewater Treatment through a Separation Process Using Bubbles without Froth Formation

Abstract

This study seeks to investigate the use of a surfactant derived from coconut oil in the recovery process of organic compounds from oily effluents. To evaluate its efficiency in oil removal and its optimal concentration for each oil/water ratio, experiments were carried out using water/oil emulsions (50, 100, 200, and 400 ppm of oil) and produced water (50 ppm) in a small-scale column. According to these experiments, it was verified that there is an optimum surfactant concentration for each emulsion, and for produced water the extraction efficiency reaches a maximum value (80%) at a surfactant concentration of 0.1 g/L^?1.