Proposal of a modal-geometrical-based master nodes selection criterion in modal analysis

Dynamic condensation techniques, used to simplify the dynamic representation of complex mechanical systems, and experimental modal identifications, in terms of number of sensors and their location, are deeply influenced by the selection of the degrees of freedom.The paper deals with a methodology for selecting physical nodes involved in model reduction or in experimental sensor location, named modal-geometrical selection criterion (MoGeSeC). It is based on the geometrical properties of the structure and on mode shape displacements, evaluated through finite element models or measured data set.By means of the well-known system equivalent reduction expansion process (SEREP) approach applied with MoGeSeC methodology, the ill conditioning of mass and stiffness matrices of the reduced model is minimized with a very low computational cost.In order to test MoGeSeC performance, some optimal nodes placement techniques, based on the maximization of the independence of modal properties or on energetic approaches, have been investigated. Finally, by means of a tailored iterative procedure, the best and the worst master node selections are performed on a particular model.Modal properties and ill conditioning of mass and stiffness matrices of reduced models are computed for several cases of different kind (1D-beam, 2D-shell, and 3D-solid elements). Finally an FE model of an exhaust pipeline, characterised by different constraint conditions, is considered and experimentally tested in order to validate the proposed methodology.     

An absorption model for the thickness effect in hydrophilic films

The permeability parameters for moisture transmission through hydrophilic films are well known to be thickness dependent, this effect appearing in permeability studies based on diffusion models. In our model we assume that, besides diffusion, some of the water vapour of the diffusion flux is removed by the hydrophilic components of the films. This water is immobilized and becomes hydration water of the hydrophilic molecules. This paper describes a diffusion–adsorption model, with thickness‐independent parameters, which explains this phenomenon.     

Shear wave Velocities for Sample Quality Assessment on a Residual Soil

For the assessment of the quality of laboratory samples, a number of methods are available, though not universally applicable to any soils. This paper examines the issue of sampling quality and its assessment using comparisons between shear wave velocity measurements in situ and in recovered samples as the base, which is very useful in naturally structured granular soils, like residual soils. For this purpose, cross-hole and down-hole tests were performed in the field and bender elements measurements were made on triaxial samples collected from two experimental sites on residual soil from Porto granite. Various sampling techniques and tools were used, including block sampling and different tube samplers. The analysis of the results has led to a new classification of sampling quality and sample condition based on the comparison of normalised shear wave velocities in the field and in the laboratory.     

The Influence of Geometrical and Operational Factors on Supercooling Capacity in Strawberries: A Simulation Study

Supercooling is still today one of the most challenging physical phenomena to be modelled in food bioprocess engineering. In this study, we evaluate the capacity of a finite-element-cellular automata (FEM-CA) approach to model the propagation of nucleation inside supercooled strawberries with five different morphologies (higher and lower volumes of vascular tissue, pulp, and central air void) frozen inside an air blast freezer under different operational conditions: initial temperature (0 to +20 °C), air temperature (−45 to −20 °C), and velocity (1 to 10 m s^− 1). Results show that nucleation is highly affected by the initial temperature and heat transfer rate during phase change. The stochastic nature of nucleation only allowed us to consider it a random variable inside the model temperature restriction interval, it not yet being possible to know what triggers nucleation. However, this study allowed us to conclude that: (1) the structure of liquid water in the supercooled region plays a very significant role during the supercooling effect, (2) nucleation temperatures increase in the supercooled region due to the release of latent heat, and (3) strawberry morphology and operational variables have a profound effect on the supercooling capacity. In our opinion, supercooling is still an open subject, and only a deeper understanding of the structuring of water and dynamics of nucleation at the molecular level may lead to significant advances in the quality of frozen foods and cryopreservation.     

Microbiological and technological characterization of sourdoughs destined for bread-making with barley flour

The aim of the present study was the microbiological and technological characterization of laboratory- made sourdoughs for use in barley-flour-based bread-making. A defined multi-strain starter culture consisting of selected lactic acid bacteria (LAB) and yeasts from wheat sourdoughs was inoculated into three flour–water mixtures, composed of: (i) 100% wheat flour (ii) 50% wheat flour and 50% hull-less barley flour (composite flour); (iii) 100% hull-less barley flour. After two months of continuous propagation, the chemical characteristics of the three sourdoughs were investigated by measuring: pH, total titratable acidity and concentrations of various microbial metabolites by HPLC (i.e. lactic, acetic, phenyllactic and butyric acids and diacetyl). The microbial traits were studied through viable counts, isolation and typing of LAB and yeasts and PCR-DGGE analyses. Only Saccharomyces cerevisiae and Lactobacillus plantarum were detectable in the sourdoughs together with other lactobacilli species which were different depending on the type of flour blend used. The molecular typing of the isolates highlighted that only a few strains among those initially inoculated prevailed. The volume increases of the three types of sourdough were also investigated and a correlation was seen between an increase in the barley flour content and a reduction in the dough volume.     

Left ventricular volume estimation for real-time three-dimensional echocardiography

The application of level set techniques to echocardiographic data is presented. This method allows semiautomatic segmentation of heart chambers, which regularizes the shapes and improves edge fidelity, especially in the presence of gaps, as is common in ultrasound data. The task of the study was to reconstruct left ventricular shape and to evaluate left ventricular volume. Data were acquired with a real-time three-dimensional (3-D) echocardiographic system. The method was applied directly in the three-dimensional domain and was based on a geometric-driven scheme. The numerical scheme for solving the proposed partial differential equation is borrowed from numerical methods for conservation law. Results refer to in vitro and human in vivo acquired 3-D + time echocardiographic data. Quantitative validation was performed on in vitro balloon phantoms. Clinical application of this segmentation technique is reported for 20 patient cases providing measures of left ventricular volumes and ejection fraction.     

Analysis of particulate pollution on foodstuff and other items by environmental scanning electron microscopy

Combustion processes commonly create fine and ultrafine particles whose effects are often harmful to human health. The present study is aimed at providing more data in this field by testing the capability of environmental electron scanning microscopy of detecting and analyzing such particles. For this purpose, we examined a range of samples taken from everyday food items collected in Tuscany. The results showed that, within the examined samples, inorganic particles can be observed in the nano- and micrometer range. These particles are attributable mostly to natural processes and, in part, to food processing. Little evidence is found for particles whose origin could be attributed to industrial combustion processes, such as waste incineration.     

Active packaging material based on buriti oil – Mauritia flexuosa L.f. (Arecaceae) incorporated into chitosan films

Active and biodegradable materials have great potential in food packaging applications, improving the safety and quality of products. The objective of this study was to develop a new material based on buriti oil incorporated into a chitosan film. Different concentrations of buriti oil in dried films (2.1 g/m², 10.4 g/m², 20.8 g/m², and 31.3 g/m²) were added into a chitosan matrix (41.7 g/m²). The chitosan/buriti oil films were characterized by water‐vapor barrier properties, total water‐soluble matter (TSM), tensile properties, thermogravimetric analysis, microstructure, microbial permeation properties, and biodegradation estimation. The higher oil concentration improved the water‐vapor barrier and the buriti oil acted largely as a plasticizer and increased the elongation at break, and decreased the tensile strength (TS) of chitosan films. The total water‐soluble matter of chitosan films decreased in function of the buriti oil concentration, but the biodegradation and thermal stability increased. The chitosan films presented a microbial barrier against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43210.     

SmartVisionApp: A framework for computer vision applications on mobile devices

In this paper a novel framework for the development of computer vision applications that exploit sensors available in mobile devices is presented. The framework is organized as a client–server application that combines mobile devices, network technologies and computer vision algorithms with the aim of performing object recognition starting from photos captured by a phone camera. The client module on the mobile device manages the image acquisition and the query formulation tasks, while the recognition module on the server executes the search on an existing database and sends back relevant information to the client. To show the effectiveness of the proposed solution, the implementation of two possible plug-ins for specific problems is described: landmark recognition and fashion shopping. Experiments on four different landmark datasets and one self-collected dataset of fashion accessories show that the system is efficient and robust in the presence of objects with different characteristics.