Influence of solvents on the photoinduced birefringence in chitosan films incorporating azo dyes

The photoinduced birefringence arising from trans–cis–trans isomerization has been studied in chitosan cast films doped with the azo dye Ponceau‐S. The chitosan/Ponceau‐S films are highly resistant to several solvents, which allowed the study of their optical storage features after immersion in various solvents. We demonstrate that the induced birefringence and its dynamics are influenced by the solvent. From experiments using such different solvents as water, dimethylsulfoxide, ethylene glycol, methanol and chloroform, it was found that the induced birefringence and the writing rate increase linearly with the dielectric constant of the solvent. At high dielectric constant, photoinduced molecular reorientation is facilitated, leading both to a larger birefringence and faster dynamics. Copyright © 2007 Society of Chemical Industry     

Characterisation of Photocathodes Based on Pb Thin Film Deposited by UV Pulsed Laser Ablation简

This work deals with the deposition of lead(Pb) thin films by the U V pulsed laser ablation technique,for their further use as photocathode devices in superconducting radio frequency guns.Scanning electron microscopy and atomic force microscopy analyses were performed to study the morphological features of Pb thin films deposited on Si(100) and Nb substrates.The films showed a granular structure with a nearly fully covered surface only for that one deposited on Nb substrata X-ray diffraction measurements indicate the growth of polycrystalline Pb thin films with a preferential orientation along(111) planes.Results of the photoemission performance of Pb thin film deposited on Nb substrate showed a very encouraging average value of quantum efficiency of 6×10~(-5) through a single-photon absorption process,promoting further studies in the realisation of Pb photocathodes by this techniqua     

Determination of ethyl carbamate in cachaças produced by selected yeast and spontaneous fermentation

Cachaça is a beverage produced by the distillation of fermented must from sugarcane. During the manufacturing steps, producers commonly use naturally occurring yeasts in the preparation of the fermentation broth, resulting in spontaneous fermentation. The composition of the resulting beverages can vary greatly, especially if various species and strains of yeast are present. The beverages produced with selected yeast strains are an alternative, leading to the production of more standardized beverages. Ethyl carbamate, which is highly toxic and has carcinogenic potential, is among the possible contaminants. The objectives of this study were to determine the levels of ethyl carbamate in cachaça produced by different types of fermentation and follow its formation during the production stages. The cachaças that contained rice bran as a nutrient during the fermentation stage contained the highest levels of ethyl carbamate throughout the production process and storage. Copyright © 2016 The Institute of Brewing & Distilling     

Are cellulose nanocrystals “alien particles” to human experience?

A wide family of cellulose‐based additives are authorized worldwide as fillers and thickening agents in foods, pills, and tablets, and microcrystalline cellulose (MCC) is, among these, the most important one. Since MCC manufacturing is similar to the main production route of cellulose nanocrystals (CNCs), it is reasonable to wonder whether the MCC would contain CNCs as minor components. In this Short Communication, we provide first results about the occurrence of CNCs in MCC, observed by dynamic light scattering and transmission electron microscopy after serial filtrations of MCC suspensions. The incidence of cellulose nanoparticles has been proved in several different trials in our ongoing works on diverse MCC samples, and the nanoparticles isolated showed shape and dimensions similar to those commonly produced by acidic hydrolysis at laboratory level. Therefore, the presence of CNCs in many products is considered as a certainty. The foods and the pharmaceuticals we have been consuming so far do indeed contain traces of CNCs to such an extent that this wide presence in consumed products should be taken into account when considering possible limitations of the use of these nanoparticles in food contact materials manufacture.     

Effect of High Hydrostatic Pressure (HHP) Treatment on Edible Flowers’ Properties

Edible flowers are increasing worldwide because they can improve the appearance, taste, and aesthetic value of food, aspects that the consumer appreciates. However, some of these are highly perishable and have a short shelf-life. To overcome these problems, high hydrostatic pressure (HHP) food processing might be applied, allowing producing high-quality food with enhanced safety and increased shelf-life. The application of HHP to vegetables has been extensively discussed and is already an industrial reality, but information on edible flowers is scarce and incomplete. Thus, in order to summarize the current knowledge on potential applications of HHP treatment in edible flowers and to determine the effect of this treatment on physical (e.g., color and texture) and nutritional characteristics as well as on microbial and enzymatic inactivation, a literature review was performed. It was stated that broccoli and cauliflower (inflorescences, usually not considered by consumers as flowers) have been the most studied, existing few information for other edible flowers. Thus, much more works are needed to better understand the effect and mechanisms behind HHP, and to define the adequate technological conditions for each flower.     

Influence of procedures and transfer modes in MAG welding in the reduction of deformations on marine structure panels

With the growth of the Brazilian shipbuilding industry, problems from the production processes emerged in the form of distortions and residual stresses. This study researched the influence of welding procedures (sequence, welding direction and reverse pass) and transfer modes (MAG-CC, MAG-STT and MAG-CW) on distortion values. All of the welds were performed with ER70S-6 wire and pure CO₂ shielding gas in the short-circuit mode. It was observed that the most important variable was change of welding direction, which is directly connected to restriction levels of the test panel. The sequences used showed little effect on the distortion values. The reverse pass had low distortion values, yet was unproductive. It was observed that the distortion values were similar for the processes and MAG-STT. The panels welded by the MAG-CW process obtained the lowest distortion values measured.     

Dynamics of the yeast flora in artisanal country style and industrial dry cured sausage (yeast in fermented sausage)

Yeast can act as an adjunct in the sausage-making process as a way to prevent or reduce excessive acidification during aging of products. Two kinds of process were studied: industrial and artisanal country style. Three hundred and fifty three yeast strains were isolated, characterized and identified by biochemical and molecular techniques. Evolution of pH, Aw, weight loss, bacterial growth and proteolytic and lipolytic activity was studied. Final pH in artisanal country style product was higher than in the industrial sausage. There was little difference noted between final weights of products but it was observed a lower yeast count in artisanal country style sausage. No relevant difference was observed in center or surface yeast count in both products. The biochemical assay identified six yeast genera and the molecular test confirmed four different genera, and further analysis showed predominance of the genera Debaryomyces. The relations between this four genera and isolation point (center or surface of sausage) were established. The presence of yeast in the center/surface of ART sausage was more prevalent than in the same places of industrial sausage.     

Investigations on the hp-Cloud Method by solving Timoshenko beam problems

 The hp-Cloud Method is a new and promising approximation technique which, without relying on a mesh, can be used in both finite and boundary element methods. In spite of its great success in solving problems with high accuracy and convergence rates, there are still a number of aspects to be qualitative and quantitatively investigated. Among these are: the sensitivity to the weight functions used in the construction of the Shepard functions, the sensitivity to the class of enrichment functions used in the p-adaptivity, the sensitivity to the cloud overlapping, and the variations of the condition number. This paper describes numerical experiments regarding some of the many choices allowed by the hp-Cloud methodology applied to Timoshenko beam problems. Since the Moving Least Squares Method is used to generate the partition of unity, some choices of weighting functions are studied and the results are compared to each other. In addition, convergence results are presented for successive h-refinements, when the number of clouds is increased, and for increasingly higher order approximation functions characterizing p-refinements. Since the new basis functions are in general not polynomials, an adaptive integration procedure is employed. The efficiency of several types of basis functions is verified. The rates of h and p convergence are determined as functions of other parameters. Also, examples of degradation of the stiffness matrix condition number is displayed and discussed.     

A reduced MIMO Wiener model for recursive identification of the depth of anesthesia

This paper presents a modeling and identification strategy for the depth of anesthesia using the propofol and remifentanil rates as the system inputs, and the bispectral index and state entropy measurements as the systems outputs. The standard model used for this purpose has twenty two patient‐dependent parameters. This high number of parameters, the little input excitation, and the small amount of output data make classical system identification approaches unsuccessful. To overcome these issues, the new model presented in this paper has six parameters, thereby meeting the parsimony principle of system identification. An extended Kalman filter algorithm is also developed and applied to real data. The good fitting results, combined with noise suppression and a recursive update of the model parameters, are promising for the design of the depth of anesthesia controllers to be used in real time platforms. Copyright © 2013 John Wiley & Sons, Ltd.