Influence of ethanol/water ratio in ultrasound and high‐pressure/high‐temperature phenolic compound extraction from agri‐food waste

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.     

Surface modification of activated carbon fabric with ozone. Part 2: Thermal analysis with TGA-FTIR and DTA

Two samples of activated carbon fabrics (ACF) with very high surface area (>1300 to >1800 m²/g) fully ozonized in the part 1 of this study were analyzed by thermogravimetric analysis (TGA) coupled both with differential thermal analysis (DTA) and FT-IR spectroscopy (TGA-FTIR). The adsorbed water and the amount of oxygenated functional groups were determined. The ozonized ACF shows an exothermal decomposition at about 181–189°C which may be due at least in part to the decomposition of ozonide and/or peroxide groups. The TGA-FTIR has revealed that the main products released from the thermal decomposition are CO₂ followed by CO. Formic acid was detected only in correspondence to the exothermal transition at 181°C and was taken as a proof of the decomposition of secondary ozonides.     

Design considerations for tunnel diode non-linear transmission lines

A tunnel diode non-linear transmission line has been investigated for second and third harmonic generation purposes. Design criteria are given and performance predictions have been obtained simulating the single diode behavior by means of a polynomial expression. An optimization of the non-linear transmission line as a harmonic generator has been obtained as a function of the number of diodes, their separation distances and the bias voltage.     

Oxidation of ethyl alcohol in trickle bed reactors: Analysis of the conversion rate

The interpretation of results of a chemical reaction carried out in a trickle bed reactor is not immediate when the key reactants are volatile; in fact some authors state that the overall conversion rate increases at very low liquid flow rates, i.e. when the catalyst is unevenly wetted. In these conditions, the reactants may penetrate inside the catalyst pellets directly through the “dry” zones; therefore the mass transfer resistance is diminished and the conversion rate can be increased. To investigate this phenomenon tests on the catalytic oxidation of ethyl alcohol dissolved in water were performed at different operating conditions in a trickle bed reactor. An interpretation of the results was tried by using two different models based on partially wetted particles. This approach considers both the cases in which “dry” zones are active or not for mass transfer and mass transfer rates are affected or not by the chemical reaction.     

Sufficient conditions for the stability of equilibrium for nonlinear conservative gyroscopic systems with first integrals

In this paper we find new first integrals of motion for a large class of nonlinear conservative gyroscopic mechanical systems. By means of the known first integrals, utilizing the classical Chetayev (1961) method, we construct a positive-definite first integral which ensures the stability of the equilibrium.     

Finite-Element Approach to the Erosion and Transport of Fine Particles in Granular Soils

The increase of the water table level presently occurring in the city of Milan led to some leakage of groundwater in underground facilities and subway tunnels. These structures, in fact, were completed about three decades ago when the water table was deeply located. To locally lower the ground water, and to eliminate or limit its flow towards the submerged openings, a series of pumping wells was placed in their vicinity. This provision, however, could lead to possible erosion of the fine fraction of the granular soil and to consequent settlements of nearby buildings. To investigate this phenomenon a finite-element approach has been developed for the analysis of the erosion and transport of the fine particles of granular soils subjected to a seepage flow. First, the continuity equation governing the problem and its finite-element formulation are discussed. Then, on the basis of the results of erosion tests presented in the literature, a law is derived that accounts for the nonlinear relationship between the total amount of eroded material, for time tending to infinity, and the velocity of seepage. Finally, this law is applied to the solution of one- and two-dimensional test examples, and some conclusions are drawn on the limits of the developed numerical model and on its possible improvement.     

ginSODA: massive parallel integration of stiff ODE systems on GPUs

The Journal of Supercomputing - Ordinary differential equations (ODEs) are a widespread formalism for the mathematical modeling of natural and engineering systems, whose analysis is generally...     

Software architectural patterns in practice: an empirical study

Software architecture involves a series of decisions based on many factors in a wide range of software development. Architects face recurring issues in different software architecture design, and to reduce huge cost and risks, software architecture decisions can rely on a set of idiomatic patterns commonly named architectural styles or patterns. Architectural pattern determines the vocabulary of components and connectors that are used in instances of the pattern together with a set of constraints to combine the two. Little contemporary data exists to document actual practices used by software professionals when selecting and incorporating architectural patterns for their projects in industry. Therefore, a comprehensive survey of software professionals was conducted to attempt to discover these practices. This exploratory survey and its quantitative results offer opportunities for further interpretation and comparison. Data from this survey are presented in this paper and include characteristics of projects, practices, organizations, and practitioners related to the usage of architectural patterns. Some of the notable findings include that architectural patterns are widely used in software projects with the Model–View–Controller being the most common. Despite reported difficulties in incorporating architectural patterns, the majority of the software professionals revealed that patterns were the most essential for completing the projects. The most difficult pattern to implement and the most expensive to adopt was the peer-to-peer, while the easiest was the client–server.

     

An effective extension of the applicability of alignment-free biological sequence comparison algorithms with Hadoop

Alignment-free methods are one of the mainstays of biological sequence comparison, i.e., the assessment of how similar two biological sequences are to each other, a fundamental and routine task in computational biology and bioinformatics. They have gained popularity since, even on standard desktop machines, they are faster than methods based on alignments. However, with the advent of Next-Generation Sequencing Technologies, datasets whose size, i.e., number of sequences and their total length, is a challenge to the execution of alignment-free methods on those standard machines are quite common. Here, we propose the first paradigm for the computation of k-mer-based alignment-free methods for Apache Hadoop that extends the problem sizes that can be processed with respect to a standard sequential machine while also granting a good time performance. Technically, as opposed to a standard Hadoop implementation, its effectiveness is achieved thanks to the incremental management of a persistent hash table during the map phase, a task not contemplated by the basic Hadoop functions and that can be useful also in other contexts.