Search results for "Vertica"
showing 10 items of 419 documents
Rail track field testing using laser/air hybrid ultrasonic technique
2003
Nondestructive testing methods used for the testing of rail in tracks worldwide can be limited by discontinuity location or orientation within the rail. Vertical split head and rail base cracks are among those types of discontinuities that are difficult to detect, which in some cases may result in a reail failure in service. A noncontact and remote hybrid ultrasonic technique has been developed by combining laser generation with air coupled detection of ultrasonic signals in rails. The test apparatus mounts on a railroad pushcart and tests are performed in motion with all components kept above the running surface of the rail track. Tracks have been tested for vertical split head and rail ba…
Influence of Geometrical Parameters, Wall Angle and Part Shape on Thickness Reduction of Single Point Incremental Forming
2014
Abstract The aim of this paper is to study the thickness reduction during the whole single point incremental forming process. The experimental setup is realized in such a way that the blank sheet is in the vertical position and forming is done using an anthropomorphic robot with six degrees of freedom. The vertical positioning of the blank sheet allows the on-line visualization using an optical measuring system of the major and minor strains and of the thickness reduction. The wall angle varied between values of 45 0 , 55 0 and 65 0 respectively. The logarithmic major strain and minor strains and logarithmic thickness reduction were analyzed in order to allow a comparison with values obtain…
Integration of green roofs&walls in urban areas
2020
Growing urbanization is associated with the emergence of environmental problems, such as the reduction of natural resources, the atmosphere pollution and the increase of the heat islands phenomenon in cities. The integration of vegetation in the urban areas, through the creation of green hanging systems, represents a possible solution to improve the energy sustainability of buildings, to combat meteoric excesses, to improve stormwater management and to reduce pollutant levels. These energy and environmental benefits are related to the properties of evapotranspiration, shading and thermal insulation of the vegetation. The work reports the results of the main studies concerning the use of han…
Vertical relationships for the European railway industry
2001
Abstract A key question in the reform process of Europe's railway industry is the decision whether to opt for a market structure that vertically integrates infrastructure and operations, or for one that separates them. In making this decision, knowledge of the relationship between operating costs and the infrastructure is fundamental. For this purpose a translogarithmic cost function is estimated, including the multi-product nature of railway companies and a measurement of the value of the infrastructure. The results show that costs deriving from freight transport and from the infrastructure are complementary, while those deriving from passenger transport and from the infrastructure are sub…
A macro-modelling approach for the analysis of infilled frame structures considering the effects of openings and vertical loads
2015
During the last decades, several macro-models have been proposed for the modelling of the infill panels' contribution to the lateral strength of frames. Despite all this effort, a robust model, which takes into account the influence of the vertical load, is not yet available. Furthermore, the influence of the very common case of infill walls with openings, such as windows and doors, has been neglected in all the code provisions that have been published so far. In this paper, an updated macro-model, based on the equivalent pin-jointed diagonal compressive strut, is presented. The proposed macro-model is able to represent the stiffening effect of the infill panel with openings by taking into …
Analysis of radiologic factors in determining premolar root canal systems
2000
Abstract Objectives. Certain tooth groups pose problems as to radiologic determination of root canal morphology. For example, the premolars may have superimposed roots that give the appearance of a single canal when 2 are actually present. This study examined the effect of X-ray tube inclination so as to visualize the complete root canal system in premolars. Study Design. One hundred extracted premolars were divided into 4 groups of 25 teeth each: 1MxP (first maxillary premolar), 2MxP (second maxillary premolar), 1MdP (first mandibular premolar), and 2MdP (second mandibular premolar). A total of 10 radiographs were made of each tooth in the horizontal and vertical planes (horizontal angles …
Diversity and composition of the microbiome associated with eggs of the Southern green stinkbug, Nezara viridula (Hemiptera: Pentatomidae).
2022
Although microbial communities of insects from larval to adult stage have been increasingly investigated in recent years, little is still known about the diversity and composition of egg-associated microbiomes. In this study, we used high-throughput amplicon sequencing and quantitative PCR to get a better understanding of the microbiome of insect eggs and how they are established using the Southern green stinkbug Nezara viridula (L.) (Hemiptera: Pentatomidae) as a study object. First, to determine the bacterial community composition, egg masses from two natural populations in Belgium and Italy were examined. Subsequently, microbial community establishment was assessed by studying stinkbug e…
Submerged speleothems and sea level reconstructions: a global overview and new results from the Mediterranean Sea
2021
This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Fa…
Markers of the last interglacial sea level high stand along the coast of Italy: Tectonic implications.
2006
A compilation of the Marine Isotope Substage (MIS) 5.5 high stand (similar to 125Ka) sites spanning the coastline of Italy allows a picture of the vertical displacement pattern affecting the Central Mediterranean coasts since the Late Pleistocene to be drawn. For each of the 246 listed sites, the accurate elevation of the high stand is defined through well-known markers. Coupled with a refilled age assessment locally Supported by new radiometric dating, these markers provide robust constraints oil deformation. Significant alongshore differences in site elevation between + 175 and - 125 m a.s.l. resulted from the interplay of regional and local tectonic processes, including faulting and volc…
The Effect of Nonlinear Response of the Primary System in Nonconventional TMDs
2023
Tuned Mass Dampers (TMD) have been widely used in the passive vibration control of engineering structures, both under wind and seismic loads. Under wind loads, a proper frequency tuning ensures a significant response reduction of the primary structure. While under wind loads the structure is likely to remain in the elastic range of behaviour, when large earthquakes occur it can experience inelastic deformations and damage, with a consequent de-tuning effect. In this paper, nonconventional TMDs with large mass ratios, realized through Interstory Isolation Systems (IIS), are considered and the influence of the inelastic behaviour of the primary system on the overall structure response is anal…