Last generation instrument for agriculture multispectral data collection

In recent years, the acquisition and analysis of multispectral data are gaining a growing interest and importance in agriculture. On the other hand, new technologies are opening up for the possibility of developing and implementing sensors with relatively small size and featuring high technical performances. Thanks to low weights and high signal to noise ratios, such sensors can be transported by different type of means (terrestrial as well as aerial vehicles), giving new opportunities for assessment and monitoring of several crops at different growing stages or health conditions. The choice and specialization of individual bands within the electromagnetic spectrum ranging from the ultraviolet to the infrared, plays a fundamental role in the definition of the so-called vegetation indices (eg. NDVI, GNDVI, SAVI, and dozens of others), posing new questions and challenges in their effective implementation. The present paper firstly discusses the needs of low-distance based sensors for indices calculation, then focuses on development of a new multispectral instrument specially developed for agricultural multispectral analysis. Such instrument features high frequency and high resolution imaging through nine different sensors (1 RGB and 8 monochromes with relative band-pass filters, covering the 390 to 950 nm range). The instrument allows synchronized multiband imaging thanks to integrated global shutter technology, with a frame rate up to 5 Hz; exposure time can be as low as 1/5000 s. An applicative case study is eventually reported on an area featuring different materials (organic and non-organic), to show the new instrument potential. Last generation instrument for agriculture multispectral data collection. Available from: https://www.researchgate.net/publication/317596952_Last_generation_instrument_for_agriculture_multispectral_data_collection [accessed Jul 11, 2017]

CONFRONTO NUMERICO E SPERIMENTALE TRA LA VERSIONE RIVETTATA E INCOLLATA DI UNA GIUNZIONE MECCANICA

Le giunzioni metalliche incollate offrono diversi vantaggi nei confronti dei tradizionali collegamenti meccanici (rivettatura, bullonatura, ecc.), tuttavia richiedono un’estensiva caratterizzazione meccanica al fine di garantire un’adeguata affidabilità delle strutture in cui vengono inserite. In questo lavoro si presentano i risultati delle prove sperimentali e delle simulazioni numeriche condotte nell’ambito della riprogettazione di una giunzione rivettata di un componente reale, sfruttando la tecnologia dell’incollaggio. L’adesivo usato è una resina epossidica bicomponente, caratterizzata attraverso una campagna di prove sperimentali e simulazioni numeriche, su provini di tipo single-lap e T-peel. Si presenta quindi un confronto, sia numerico che sperimentale, delle prestazioni meccaniche della giunzione rivettata con l’analoga giunzione incollata. I risultati hanno evidenziato un sostanziale miglioramento in termini di rigidezza e resistenza con l’uso della tecnica dell’incollaggio

Four-point bending test on a middle strength rock: Numerical and experimental investigations

Developing a reliable numerical modelling technique is considered as challenge for fracture assessment of the geological materials, which are much subjected to hydrostatic pressure. For this purpose, the mechanical behaviour and the fracture pattern of a middle strength rock material, called Pietra Serena sandstone, is investigated both numerically and experimentally under a Four-Point Bending (also called Flexural) testing program. For the numerical approach, an innovative method, namely FEM-coupled to-SPH, is exploited due to its capabilities in dealing with rock mechanics related issues. Two different material models, which are the Karagozian and Case Concrete (KCC) and the Extended (Linear) Drucker-Prager, are exerted to assess their capabilities. The Flexural strength and the crack initiation area are studied based on the state of the stress in various parts of the specimen in both models, and finally the results obtained from the numerical models are compared with the data obtained from the experimental tests in order to assess the capability of the modelling approach

Strain wave acquisition by a fiber optic coherent sensor for impact monitoring

A novel fiber optic sensing technology for high frequency dynamics detection is proposed in this paper, specifically tailored for structural health monitoring applications based on strain wave analysis, for both passive impact identification and active Lamb wave monitoring. The sensing solution relies on a fiber optic-based interferometric architecture associated to an innovative coherent detection scheme, which retrieves in a completely passive way the high-frequency phase information of the received optical signal. The sensing fiber can be arranged into different layouts, depending on the requirement of the specific application, in order to enhance the sensor sensitivity while still ensuring a limited gauge length if punctual measures are required. For active Lamb wave monitoring, this results in a sensing fiber arranged in multiple loops glued on an aluminum thin panel in order to increase the phase signal only in correspondence to the sensing points of interest. Instead, for passive impact identification, the required sensitivity is guaranteed by simply exploiting a longer gauge length glued to the structure. The fiber optic coherent (FOC) sensor is exploited to detect the strain waves emitted by a piezoelectric transducer placed on the aluminum panel or generated by an impulse hammer, respectively. The FOC sensor measurements have been compared with both a numerical model based on Finite Elements and traditional piezoelectric sensors, confirming a good agreement between experimental and simulated results for both active and passive impact monitoring scenarios

Relationship between prolactin plasma levels and white matter volume in women with multiple sclerosis

BACKGROUND: The role of prolactin (PRL) on tissue injury and repair mechanisms in multiple sclerosis (MS) remains unclear. The aim of this work was to investigate the relationship between PRL plasma levels and brain damage as measured by magnetic resonance imaging (MRI). METHODS: We employed a chemiluminescence immunoassay for measuring plasma levels of PRL. We used a 1.5 T scanner to acquire images and Jim 4.0 and SIENAX software to analyse them. RESULTS: We included 106 women with relapsing remitting (RR) MS and stable disease in the last two months. There was no difference in PRL plasma levels between patients with and without gadolinium enhancement on MRI. PRL plasma levels correlated with white matter volume (WMV) (rho = 0.284, p = 0.014) but not with grey matter volume (GMV). Moreover, PRL levels predicted changes in WMV (Beta: 984, p = 0.034). CONCLUSIONS: Our data of a positive association between PRL serum levels and WMV support the role of PRL in promoting myelin repair as documented in animal models of demyelination. The lack of an increase of PRL in the presence of gadolinium enhancement, contrasts with the view considering this hormone as an immune-stimulating and detrimental factor in the inflammatory process associated with MS

Bisphosphonate-associated jaws osteonecrosis: an important complication of oncology treatment

Os bisfosfonatos são um grupo de medicamentos utilizados no tratamento de doenças malignas metastáticas e em outras doenças ósseas como osteoporose e doença de Paget. A despeito dos seus benefícios, uma importante complicação denominada de osteonecrose dos maxilares vem sendo observada nos pacientes usuários crônicos dos bisfosfonatos que se caracteriza clinicamente por exposições ósseas na região maxilofacial persistente, acompanhadas de osteomielite, geralmente sintomáticas e cujo tratamento é complexo. Este estudo tem por objetivo revisar a literatura sobre a osteonecrose associada ao uso dos bisfosfonatos, em especial, em oncologia, no período de 2003 a 2008. Serão apresentados e discutidos os fatores de risco, aspectos etiopatogênicos, clínicos, imagenológicos, terapêuticos e preventivos desta doença. Devido à dificuldade de tratamento da osteonecrose associada aos bisfosfonatos, o foco deve ser a prevenção, sendo o ideal a eliminação de quadros infecciosos orais antes da terapia com os bisfosfonatos ter sido iniciada e minimizar traumas em boca após o uso destes medicamentos.Bisphosphonates are drugs used in the treatment of malignant metastatic diseases and in other bone lesions such as osteoporosis and Paget´s disease. Besides their benefits, jaw osteonecrosis, an important side effect, has been observed in long-term users of these drugs. Jaw osteonecrosis is clinically characterized by prolonged maxillary and mandible bone exposure accompanied by osteomyelitis. These lesions are usually symptomatic and difficult to treat. This study has the objective of reviewing publications from 2003 to 2008 about bisphosphonate-associated jaw osteonecrosis, in particular in relation to oncology. Risk factors, and etiopathological, clinical, radiographic, therapeutic, and preventive aspects of this condition are presented and discussed. Due to the difficulty to treat this disease, the focus must be prevention, with the ideal therapy being the elimination of oral infections before treatment with bisphosphonates is initiated thereby attempting to minimize possible traumas to the mouth with the use of these medications

microstructural numerical modeling of al2o3 ti composite

Abstract The present work focuses on the study of a numerical model of a ceramic/metal particle reinforced composite material that has the potential to be used in challenging engineering applications. The composite has been developed combining the specific properties of ceramic and metal in order to improve the overall mechanical characteristic compared to the characteristics of the individual materials only. In particular, the purpose of the composite is to improve the fracture toughness of the single ceramic in order to use it as protection against impact. Finite element modeling and analysis of a microstructure-based model have been used to analyze the mechanical behaviour of the particle reinforced composite in a virtual tensile test. The microstructure-based model has been created from scanning electron microscopy (S.E.M.) images identifying the areas and the edges of the two components present in the composite. The microstructure-based approach has been chosen for calculating the elastic properties starting from the material behaviour at the grain level in the ceramic and metal particles. The properties of the different individual particles have been used separately as the input to define the global mechanical properties of the composite. The aim of this work is to create and validate the microstructure-based model by replicating the results available from experimental data for the elastic properties of the composite. Furthermore, the numerical results have been compared with analytical models for particle reinforced composites to have a wider knowledge of the capability of the model created

Sleep habits and complaints of adults in the city of São Paulo, Brazil, in 1987 and 1995

This study compares the prevalence of complaints of insomnia, excessive diurnal sleepiness, parasomnias, and sleep habits of the adult population in the city of São Paulo, Brazil, estimated in surveys carried out in 1987 and 1995. Representative samples of 1000 adult residents per survey were interviewed using a validated structured sleep questionnaire, the UNIFESP Sleep Questionnaire. Difficulty maintaining sleep, difficulty initiating sleep and early morning awakening, occurring at least three times a week, were reported in 1987 and 1995, by 15.8/27.6, 13.9/19.1, and 10.6/14.2% of the interviewees, respectively, significantly increasing throughout time. These sleep problems were more often found among women. Frequencies of excessive diurnal sleepiness and sleep attacks were unchanged comparing 1987 with 1995 (4.5 vs 3.8 and 3.1 vs 3.0%, respectively). Parasomnia complaints remained unchanged, with the exception of leg cramps, which doubled in prevalence from 1987 to 1995 (2.6 to 5.8%). Snoring was the most common parasomnia (21.5% in 1995), reported more often by men than by women, and somnambulism was the least common (approximately 1%). Besides sleeping slightly less, interviewees went to bed and woke up later in 1995. Approximately 12% of the subjects in both surveys had consulted a physician due to sleep problems and 3.0% reported habitual use of sleep-promoting substances in 1995. Overall, there was a significant increase in insomnia complaints from 1987 to 1995 in the general population of the city of São Paulo. This major change over a little under a decade should be considered as an important public health issue.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicobiologiaUNIFESP, EPM, Depto. de PsicobiologiaSciEL

a comparison of state based peridynamics and solid mesh to sph conversion techniques to reproduce fragmentation of a ceramic tile subject to ballistic impact

Abstract This paper presents a comparison of two present meshfree approaches for modelling brittle material in case of ballistic impact, where extensive cracking and fragmentation is present. These phenomena are very unfeasible to simulate with a standard Lagrangian technique thus alternative methods have been considered in the last years. A comparison between two methods is the main aim of the present article. Smoothed Particle Hydrodynamics (SPH) is an almost consolidated method that exploit the description of a continuum by means of discrete elements whose properties are "smoothed" by a Kernel Function. In this paper a procedure that exploits the transition from finite elements (FE) to SPH particles, following the onset of an erosion criterion is used. This approach and its results are then compared to the recent state-based Peridynamics. Peridynamics method is based on integral equation and allow a direct application to discontinuities and fractures. The results from both methods are critically compared with experimental data and show that the damage morphology is reproduced similarly by both approaches; however less computation efforts are required when peridynamics are used