Simultaneous Hydrogen Production and Acetic Acid Degradation by Heterogeneous Photocatalysis using a Metallurgical Waste as Catalyst

Topics in Catalysis - This study presents the generation of a renewable fuel using acetic acid as electron donor, copper slag (CS) as photocatalyst and UV–Vis irradiation. The CS was...     

Improvement of water transport mechanisms during potato drying by applying ultrasound

BACKGROUND: The drying rate of vegetables is limited by internal moisture diffusion and convective transport mechanisms. The increase of drying air temperature leads to faster water mobility; however, it provokes quality loss in the product and presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during convective drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve convective drying of potato and quantify the influence of the applied power in the water transport mechanisms. RESULTS: Drying kinetics of potato cubes were increased by the ultrasonic application. The influence of power ultrasound was dependent on the ultrasonic power (from 0 to 37 kW m^?3), the higher the applied power, the faster the drying kinetic. The diffusion model considering external resistance to mass transfer provided a good fit of drying kinetics. From modelling, it was observed a proportional and significant (P < 0.05) influence of the applied ultrasonic power on the identified kinetic parameters: effective moisture diffusivity and mass transfer coefficient. CONCLUSIONS: The ultrasonic application during drying represents an interesting alternative to traditional convective drying by shortening drying time, which may involve an energy saving concerning industrial applications. In addition, the ultrasonic effect in the water transport is based on mechanical phenomena with a low heating capacity, which is highly relevant for drying heat sensitive materials and also for obtaining high‐quality dry products. Copyright © 2011 Society of Chemical Industry     

Influence of High-Intensity Ultrasound on Drying Kinetics of Persimmon

Drying persimmon pieces is recognized as a way to preserve and add value to the excess production of the fruit in Spain. To this end, air drying kinetics of persimmon cylinders (30 mm height and 13 mm diameter) were determined under different drying conditions: 8 air drying velocities (0.5, 1, 2, 4, 6, 8, 10, and 12 m/s) with and without application of high-intensity ultrasound (21.8 kHz and 154.3 dB). The drying process was modeled using two diffusion models with and without the influence of external resistance to drying. From the effective diffusivity and the mass transfer coefficient identified from the data it was concluded that high-intensity ultrasound increased the drying rate at the lowest air velocities tested, affecting both external and internal resistances.     

Application of emerging technologies to obtain legume protein isolates with improved techno-functional properties and health effects

Current demand of consumers for healthy and sustainable food products has led the industry to search for different sources of plant protein isolates and concentrates. Legumes represent an excellent nonanimal protein source with high-protein content. Legume species are distributed in a wide range of ecological conditions, including regions with drought conditions, making them a sustainable crop in a context of global warming. However, their use as human food is limited by the presence of antinutritional factors, such as protease inhibitors, lectins, phytates, and alkaloids, which have adverse nutritional effects. Antitechnological factors, such as fiber, tannins, and lipids, can affect the purity and protein extraction yield. Although most are removed or reduced during alkaline solubilization and isoelectric precipitation processes, some remain in the resulting protein isolates. Selection of appropriate legume genotypes and different emerging and sustainable facilitating technologies, such as high-power ultrasound, pulsed electric fields, high hydrostatic pressure, microwave, and supercritical fluids, can be applied to increase the removal of unwanted compounds. Some technologies can be used to increase protein yield. The technologies can also modify protein structure to improve digestibility, reduce allergenicity, and tune technological properties. This review summarizes recent findings regarding the use of emerging technologies to obtain high-purity protein isolates and the effects on techno-functional properties and health.     

Approximations for <Emphasis Type="Italic">F</Emphasis>-tests which are ratios of sums of squares of independent variables with a model close to the normal

The F _(a,b)-distribution is very frequently used in Statistics to compute significance levels when the individual observations follow a normal distribution. In this paper, we obtain good analytic approximations for the p-value and critical value of tests in which the test statistic is a ratio of sums of squares of independent and identically distributed random variables (i.e., F-tests under a normal) when the underlying distribution is close to but different from the normal. The class of distributions for the approximations to be valid is delimited with a “breakdown condition.” With these approximations, we can study, for example, the robustness of validity of this kind of tests and corroborate the thought that they have robustness of validity if only the second degree of freedom depends on a large n and that they do not have robustness of validity if both degrees of freedom depend on n and are similar. These robustness properties are displayed with the “Robustness of Validity Plot,” a diagram of the nominal level versus the actual level of a test. The simulations carried out confirm these conclusions.     

Influence of monomeric concentration on mechanical and electrical properties of poly(styrene-co-acrylonitrile) and poly(styrene-co-acrylonitrile/acrylic acid) yarns electrospun

Two series of copolymers were synthesized by emulsion polymerization: poly(styrene-co-acrylonitrile) P(S:AN) and P(S:AN-acrylic acid) P(S:AN-AA). The monomeric concentrations in both series were: 0:100, 20:80, 40:60, 50:50 (wt%:wt%), and 1 wt% of AA. The copolymers were dissolved in N,N-dimethylformamide (4–10 wt%) and were electrospun. Polymeric yarns were collected using a blade collector. The synthesized and fabricated materials were characterized by known techniques. Mechanical and electrical properties of polymeric yarns indicated a dependence of monomeric concentration. Elastic modulus increases as acrylonitrile concentration increases (up to 30 MPa). Yarns were submitted to degradation process into saline solution, where the acrylic acid content kept a constant elastic modulus at long times. The electrical current into yarns was higher when the concentration is 50:50 wt%:wt% (1.2 mA). The cytotoxicity results showed a cell viability close to 100% for yarns without AA.     

Picea mariana bark: A new source of trans-resveratrol and other bioactive polyphenols

The ethyl acetate soluble fraction obtained from the hot water extract of Picea mariana bark (BS-EAc(f)) has been demonstrated to have anti-inflammatory and antioxidant properties. Thus, in the current study, we isolated and characterised major compounds of this fraction by HPLC, NMR and MS analyses. On the whole, 28 compounds were identified, among which were five neolignans, seven lignans, trans-resveratrol, three phenolic acids and four flavonoids. To the best of our knowledge, 2,3-dihydro-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-(2S,3S)-1,4-benzodioxin-6-propanol, threo and erythro 3-methoxy-8,4'-oxyneolignan-3',4,7,9,9'-pentol, pallasiin, (±) epi-taxifolin, homovanillyl alcohol, orcinol and 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol are reported for the first time in the Picea genus. P. mariana dry bark contains at least 104μgg(-1)dw of trans-resveratrol and it could be therefore considered as a new accessible source of this molecule. This study provides novel information about the identity of major compounds present in BS-EAc(f), which is essential for the understanding of the anti-inflammatory and nutraceutical potential of this extract.     

The Role of Parametric Assumptions in Adaptive Bayesian Estimation.

Variants of adaptive Bayesian procedures for estimating the 5% point on a psychometric function were studied by simulation. Bias and standard error were the criteria to evaluate performance. The results indicated a superiority of (a) uniform priors, (b) model likelihood functions that are odd symmetric about threshold and that have parameter values larger than their counterparts in the psychometric function, (c) stimulus placement at the prior mean, and (d) estimates defined as the posterior mean. Unbiasedness arises in only 10 trials, and 20 trials ensure constant standard errors. The standard error of the estimates equals 0.617 limes the inverse of the square root of the number of trials. Other variants yielded bias and larger standard errors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)