Search results for "Correlation"
showing 10 items of 2282 documents
A step further in the comprehension of the magnetic coupling in gadolinium(III)-based carboxylate complexes
2013
Three new gadolinium(III) complexes of formula [Gd4(bta) 3(H2O)16]n·12nH2O (1), [Gd4(bta)3(H2O)12] n·18nH2O (2) and [Gd2(H 2bta)(bta)(H2O)2]n·4nH 2O (3) (H4bta = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized and their structures determined by X-ray diffraction. 1 and 3 are three-dimensional compounds whereas 2 exhibits a two-dimensional structure. The ability of the bta4- to adopt different coordination modes accounts for these high dimensionalities although it precludes a rational structural design. The structures of 1-3 have in common the double oxo-carboxylate bridge between gadolinium(III) ions (μ-O: κ2O,O′) either as a discrete units (1 and 2) or as a chain (3) and one (3)…
THE RELATIONSHIP BETWEEN DIFFUSE AND TOTAL SOLAR RADIATION IN COMPUTER SIMULATION OF SOLAR ENERGY SYSTEMS
1978
ABSTRACT The diffuse to total radiation correlation developed by Liu and Jordan [1] was tested for three Italian locations. An acceptable agreement was found between the regression lines in [1] and the ones found for two of the three locations. Using measured hourly values of total solar radiation on a horizontal surface, the corresponding hourly values of total solar radiation on an inclined surface at 45° facing south were computed with both the Liu and Jordan and the Loudon [6] method for estimating the diffuse radiation. Results show that approximately the same degree of accuracy in the prediction is achievable with both methods and that the difference between the measured total monthly…
Speckle Interferometry Analysis of Full-bending Behavior of GFRP Pultruded Material
2016
Abstract The use of Glass Fiber Reinforced Polymer materials (GFRP) has increased in the last years even among civil structural engineering due to their high specific strength, lightweight and excellent corrosion resistance. With application of the pultrusion method, the manufacture of large-scale profiles with various cross-section forms became potentially possible with relatively low costs. Usually two different technological approaches are available to realize the element: in the first one a mat-roving-mat sequence is adopted, in the second one only roving is present. Continuous filament mat (CFM, fibers distributed randomly in all directions) is often used to build up laminate thickness…
Experimental Study Regarding PA and PE Sheets on Single Point Incremental Forming Process
2021
The present paper aims to present an experimental study on the behaviour of PA and PE sheets during the single point incremental forming. Due to the fact that the purpose of this research is to study the behaviour of PA and PE sheets during the single point incremental process both in terms of process forces and in terms of major and minor strain and thickness reduction, a Kuka Kr210 robot was chosen as an alternative to using a universal milling machine. The specimens were made of 3 mm PA and PE sheets. The size of the sheets was 250 mm x 250 mm. The forces measured on the three directions of the coordinate axes were compared. To measure the major strain, minor strain and thickness reducti…
On the use of Digital Image Correlation (DIC) for evaluating the tensile behaviour of BFRCM strips
2019
Abstract. Fibre Reinforced Cementitious Matrix (FRCM) composites are becoming largely adopted for retrofitting masonry structures. These materials offer several advantages in comparison to Fibre Reinforced Polymer (FRP) composites, such as good resistance to fire and high temperatures, vapour permeability, possibility to be applied on wet surfaces, higher compatibility with the masonry substrate. However, the tensile behavior of FRCM materials is more complex compared to FRP composites, due to the limited tensile strength of the cement-based matrix. For this reason, FRCM materials require appropriate tensile characterization and, in this context, the use of non-conventional measurement syst…
Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets
2017
This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip-off failure of the concrete cover. The CFRP sheets were fixed to the concrete surface by epoxy adhesive as well as combined with various configurations of small-diameter steel pins for mechanical fastening to form a hybrid connection. Such hybrid jointing techniques were found to be particularly adva…
In Vitro Measurement of Strain Localization Preceding Dissection of the Aortic Wall Subjected to Radial Tension
2020
AbstractBackgroundAortic dissection (AD) is a common pathology and challenging clinical problem. A better understanding of the biomechanical effects preceding its initiation is essential for predicting adverse events on a patient-specific basis. Moreover, the predictability of patient-specific biomechanics-based computational models is hampered by uncertainty about boundary conditions and material properties.ObjectivePredisposition of thoracic aortic aneurysms (TAA) to ADs can be related to the degradation of biomechanically important constituents in the aortic wall of TAAs. The goal of the present study is to develop a new methodology to measure strain fields in aortic tissues subjected to…
Experimental application of digital image correlation for the tensile characterization of basalt FRCM composites
2021
Abstract Composites made with inorganic matrix, namely fabric reinforced cementitious mortar (FRCM) composites are becoming widespread as strengthening materials for existing masonry structures. These composites are made of a dry grid of fibres embedded in an inorganic matrix. FRCMs can be considered a valid alternative to traditional organic composites such as fibre reinforced polymers (FRPs) because of their better compatibility with the masonry support. This work presents an experimental study for the tensile characterization of a basalt fabric reinforced cementitious mortar (BFRCM) composite. Tensile tests were carried out on coupons reinforced with one, two or three layers of grid to i…
A DIC-based study of flexural behaviour of roving/mat/roving pultruded composites
2015
Abstract This paper reports a study of the flexural behaviour and resultant failure modes in E-glass/polyester pultruded composites. The digital image correlation (DIC) method is used to estimate the effect of fibre orientation on failure behaviour in thick beams, taking into account the presence of continuous filament mat layer (CFM) in the stacking sequence. In particular, the tests were carried out for specimens with off-axis angle of 0°, 7.5°, 15°, 30°, 45° and 90°. The crack initiation and the failure mechanisms depend on the mutual interaction between the stiffness properties of different areas in the stacking sequence. An influence index (I) was introduced to evaluate the magnitude o…
Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications
2018
Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Corr…