Operational modal testing and FE model tuning of a cable-stayed bridge

The paper presents the results obtained from the application of different output-only modal identification techniques to ambient response data collected in two dynamic tests of a cable-stayed bridge and the subsequent finite element model correlation analysis. The first test, performed by using a traditional data acquisition system with servo-accelerometers, was aimed at investigating the vertical dynamic characteristics of the bridge. In the second test, an innovative radar vibrometer was used for non-contact measurement of deflection time series of the forestays and the identification of local natural frequencies of the stay cables.In the theoretical study, vibration modes were determined using a 3D Finite Element model of the bridge and the information obtained from the field tests, combined with a classic system identification technique, provided a linear elastic model, accurately fitting the modal parameters of the bridge in its present condition.     

Study of the content in volatile compounds during the aging of sweet Sherry wines obtained from grapes cv. Muscat and fermented under different conditions

Several experiments of aging in oak wood and stainless steel of sweet Sherry wines obtained from grapes cv. Muscat fermented under different enological conditions have been carried out. These wines were periodically sampled and their volatile content was analyzed using SBSE–GC–MS. A sensory study was also carried out. Data were submitted to different statistical techniques. An important influence of the three factors considered, fermentation type, aging type, and aging time, have been observed. In cluster analysis, the grouping obtained demonstrated that the volatile compounds considered possess sufficient explanatory power to detect the type of aging process and differentiate the two yeast strains studied. In the case of the linear discriminant analysis, high percentages of correct classification were obtained for the three factors considered. Taking into account the global volatile profile, the factor “aging type” (oak cask or stainless steel) has demonstrated the highest influence on the volatile content of the wines, with those wines from Experiments D4 and D5 (fermented with S. bayanus) and aged in oak wood clearly differentiated from those ones fermented with S. cerevisiae and aged in wood or stainless steel. From a sensorial point of view, the wines fermented with S. Cerevisiae and aged in wood (D1C and D2C) were the most valued ones.     

Modeling of the processing force for performing ECAP of circular cross-section materials by the UBM

Equal channel angular extrusion or pressing (ECAP) is a process used to impart severe plastic deformations (SPD) (ε?<<?1) to materials with the aim of improving their mechanical properties by reducing the grain size. In this study, an analytical modeling of the ECAP processing force required, taking circular cross-section for ECAP dies into consideration, is developed where non-strain hardening materials are processed. To obtain the equation that relates the geometry and required force, the upper bound method was used after taking an appropriate and admissible field into consideration. In addition, a comparison between analytical methods and experimental results was made. In order to perform the experimental tests, an F-1050-AA (F means as fabricated) was selected and processed at room temperature. This alloy has a yield stress of 70?MPa and an insignificant strain hardening. The experimental results obtained agree closely with those provided by the analytical formulation. With this study, it is possible to have an analytical approach to the required force for performing the ECAP process. This could help scientists and practical engineers involved in SPD processes such as ECAP, to optimize ECAP dies and the process itself thanks to the knowledge of the analytical expressions of the required force.     

Accelerated aging of a Sherry wine vinegar on an industrial scale employing microoxygenation and oak chips

A study of accelerated aging on an industrial scale, employing both microoxygenation and oak chips, of a Sherry wine vinegar has been carried out. The effect of these two factors, microoxygenation and oak chips, on polyphenolic and volatile compounds, and sensorial parameters has been evaluated. The dose of oxygen applied to the vinegar and the use of chips provoke important changes in its content in polyphenols and volatile compounds and make it similar to the profile obtained using traditional aging. An alternative method of aging is proposed, using 5 g/L of chips and a dose of oxygen around 70 mL/L month. With the proposed method, and according to the sensorial and analytical results obtained, vinegars similar to those traditionally aged can be obtained by accelerated aging with microoxygenation and chips in shorter periods of time. In our case, a final reduction of 86% of time is achieved with the proposed method.     

Capsaicinoid Contents in Peppers and Pepper-Related Spicy Foods

The quantification of the major capsaicinoids, namely nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin, present in spicy foods made from peppers has been performed. The capsaicin content is directly related to the pungency properties of foods that contain hot peppers. The samples studied included 10 different dried hot peppers, 19 hot sauces, 4 kinds of paprika, and 4 different ketchups. The range of concentrations of capsaicinoids found were as follows: dried hot peppers (554.1–1705.9 mol kg^?1), paprikas (582.0–665.0 mol kg^?1), spicy ketchups (4.0–12.4 mol kg^?1), and hot sauces (4.6–843.8 mol kg^?1). Variability in the capsaicinoid content was found, with capsaicin and dihydrocapsaicin present at the highest levels. The capsaicin content was generally higher than the dihydrocapsaicin content.     

Hydrogen production through NaBH4 hydrolysis over supported Ru catalysts: An insight on the effect of the support and the ruthenium precursor

The NaBH₄ hydrolysis over Ru catalysts on different supports was here investigated. It was found that the support has a strong effect on the catalytic activity which was found to be in the order: Ru/activated carbon >> Ru/CeO₂ > Ru/TiO₂ > Ru/γ-Al₂O₃. On the most active system, namely Ru/activated carbon, the effect of the Ru loading and the metal precursor (RuCl₃ and Ru(NO)(NO₃)₃) was studied in more detail. Tests carried out with and without temperature control demonstrated that, for each precursor, the activity increases on increasing the Ru content. Moreover samples prepared by RuCl₃ were more active than the corresponding ones prepared by Ru(NO)(NO₃)₃. Characterization data, namely CO chemisorption and TEM analysis, point out that the Ru particles size is strongly affected from the Ru precursor used, Ru(NO)(NO₃)₃ resulting in very small Ru particles (diameter < 1 nm), RuCl₃ leading to Ru nanoparticles with average diameter of 2.4 nm. This latter size was found to be appropriate for the NaBH₄ hydrolysis reaction, which is proposed to be a structure sensitive reaction.     

Defining amplifier’s gain to maximize the transmission rate in optical systems using evolutionary algorithms and swarm intelligence

Optical networks are currently the only technology capable of providing extremely high data transmission rates. Because of this, systems must be increasingly efficient and immune to failures. One way to improve network efficiency is to use dynamic approaches like Adaptive Control of Operating Point, which consists of autonomously choosing the best operating point for optical amplifiers on the link, thus providing the best configuration concerning Quality of transmission. Unlike the previous works that focused on optimizing Optical Signal-To-Noise Ratio, our proposal and analysis are focused on maximizing the transmission rate. In this paper, we compare the results obtained by five different and widely used evolutionary and swarm-based algorithms in the search for maximizing the transmission rate in optical links. We have observed that the differential evolution provided the best results in the analyzed scenarios.

     

Spatial dependence in the technical efficiency of local banks

Cooperative banks primarily compete with one another because they target niche markets that large banks typically ignore. The current study shows that in this competitive environment, the connection between financial intermediaries affects the operational efficiency of small banks. The findings indicate that the capitalization, diversification strategies, funding costs, liquidity, credit quality, and risk of bank neighbors have spillover effects on technical efficiency. Thus, bank networks trigger a cascading effect that demands the attention of bank stakeholders.