1,348 research outputs found
Mathematical model investigation of long-term transport of ocean-dumped sewage sludge related to remote sensing
An existing, three-dimensional, Eulerian-Lagrangian finite-difference model was modified and used to examine the transport processes of dumped sewage sludge in the New York Bight. Both in situ and laboratory data were utilized in an attempt to approximate model inputs such as mean current speed, horizontal diffusion coefficients, particle size distributions, and specific gravities. The results presented are a quantitative description of the fate of a negatively buoyant sewage sludge plume resulting from continuous and instantaneous barge releases. Concentrations of the sludge near the surface were compared qualitatively with those remotely sensed. Laboratory study was performed to investigate the behavior of sewage sludge dumping in various ambient density conditions
Operational modal analysis for the characterization of ancient water towers in Pompeii
In the framework of an investigation campaign carried out in June 2015 by the authors on four ancient water towers (10\u201320 BC) in the archaeological site of Pompeii, modal analysis and output-only identification techniques were employed to extract the dynamic properties in order to assess structural vulnerabilities and support numerical model updating.
The four investigated towers (selected among the fourteen present within the archaeological site) are free-standing structures at least 6 m tall, belonging to the Castellum Aquae, i.e. the ancient aqueducts system of the city. During the Roman Age, until the destruction of Pompeii due to the volcanic eruption in 79 AD, water towers provided fresh water to houses, palaces and villas. This particular type of structures are classified as no. 1, 2, 3 and 4 by archaeological literature: no. 1 and 4 are made of soft stone masonry (tuff, limestone), while no. 2 and 3 are composed by brickwork masonry.
The paper reports the outcomes of ambient vibration tests performed on four towers in terms of extracted modal parameters using various operational modal analysis techniques. Obtained data are then used to study numerically the soil-structure interaction problem and implement model updating procedures
Calibration of the dynamic behaviour of incomplete structures in archeological sites: The case of Villa Diomede portico in Pompeii
This paper reports the research activities carried out on Villa Diomede in Pompeii, built during the "Pre-Roman period" (i.e. the 3rd century BC) and discovered between 1771 and 1774 during the archaeological excavations. It is one of the greatest private buildings of Pompeii and it is located on the western corner of the modern archeological site. Three levels compose the building: the ground floor, the lower quadriportico with a square plan and a series of colonnades on the four sides around the inner garden and the cryptoportico. Villa Diomede was damaged by the strong earthquake occurred in AD 63 that caused the collapse of the western pillars of the quadriportico and later damaged after the big eruption of Vesuvius in AD 79. In June 2015 a series of nondestructive tests (NDT) were carried out by the authors in order to obtain information on the state of conservation of the building and to assess its structural behavior. Direct and tomographic sonic pulse velocity tests, ground penetrating radar, endoscopies and operational modal analysis were performed on the remaining structural elements on the two levels of the Villa. The present paper reports the main outcomes and findings of ambient vibration tests implemented to extract the modal parameters in terms of eigenfrequencies, mode shapes and damping ratios. Operational modal analysis and output-only identification techniques were applied to single stone pillars of the quadriportico structure and then to the entire square colonnade of Villa Diomede. Results are then used to study the soil-structure interaction at a local level and extend the gained information for the numerical calibration of the whole structure. Thanks to this methodology a detailed model updating procedure of the quadriportico was performed to develop reliable numerical models for the implementation of advance structural and seismic analysis of this "incomplete" archaeological structure
Potencial das zeolitas em lobos de derrames da Fácies Gramado da Formação Serra Geral, como condicionadores de solos agrícolas no vale do Rio Taquari-Antas, Brasil.
Resumo
Pounding Effects in Simply Supported Bridges Accounting for Spatial Variability of Ground Motion: A Case Study
This study carries out a parametrical analysis of the seismic response to asynchronous earthquake ground motion of a long multispan rc bridge, the Fener bridge, located on a high seismicity area in the north-east of Italy. A parametrical analysis has been performed investigating the influence of the seismic input correlation level on the structural response: a series of nonlinear time history analyses have been executed, in which the variation of the frequency content in the accelerograms at the pier bases has been described by considering the power spectral density function (PSD) and the coherency function (CF). In order to include the effects due to the main nonlinear behaviours of the bridge components, a 3D finite element model has been developed, in which the pounding of decks at cap-beams, the friction of beams at bearings, and the hysteretic behaviour of piers have been accounted for. The sensitivity analysis has shown that the asynchronism of ground motion greatly influences pounding forces and deck-pier differential displacements, and these effects have to be accurately taken into account for the design and the vulnerability assessment of long multispan simply supported bridges
Anti-TNF-α drugs: pharmacoeconomic analysis and proper use in pharmacological treatment in rheumatoid arthritis
Sistema de informações geográficas como contribuição à utilização de pó de rocha oriundo da formação serra geral em áreas de indicações geográficas vitivinícolas no Brasil.
As áreas de indicação geográfica vitivinícola brasileiras buscam o desenvolvimento sustentável de sua produção e o uso de pó de rocha, bem como práticas de rochagem poderão contribuir para a remineralização dos solos e nutrição de plantas, o que poderá agregar valor ao produto. No entanto, o uso de rochagem é ainda incipiente nas regiões produtoras brasileiras e possivelmente as razões para isto são devidas ao desconhecimento sobre a identificação de fontes destes materiais para rochagem, bem como a distância de transporte destas fontes à área cultivada. A Embrapa Uva e Vinho possui levantamento detalhado da área vitícola das indicações geográficas como Vale dos Vinhedos, Monte Belo, Pinto Bandeira, Altos Montes e Farroupilha, todas localizadas na região vitivinícola Serra Gaúcha, no Estado do Rio Grande do Sul. A Companhia de Pesquisa de Recursos Minerais tem feito extenso levantamento de fontes de agrominerais nos diversos litotipos da Formação Serra Geral no Rio Grande do Sul, definindo materiais que melhor disponibilizam nutrientes para as plantas. No substrato da região vitivinícola Serra Gaúcha ocorrem os Fácies Caxias e Gramado da Formação Serra Geral, os quais possuem variações ao longo dos derrames. Um sistema de informações geográficas foi construído com a finalidade de formar um banco de dados georreferenciado da produção vitivinícola, incluindo as áreas fonte de material para rochagem e, além disto, estabelecendo as distâncias calculadas até as áreas de vinhedos. Foram aplicadas técnicas de geoprocessamento no programa livre gvSIG pelo cruzamento de atributos citados. A área da indicação geográfica Altos Montes, situada nos municípios de Flores da Cunha e Nova Pádua, Rio Grande do Sul, foi investigada a fim de indicar áreas mais favoráveis para obtenção de pó de rocha para ser disponibilizado à viticultura
Efficiency of alternative intensity measures for the seismic assessment of monolithic free-standing columns
This paper deals with the dynamic response of a free-standing ancient column in the Roman Agora of Thessaloniki, Greece as a means to shed more light on the complex behaviour of rocking bodies under seismic excitation. Numerical analyses utilizing discrete element method were carried out with the use of multiple seismic records selected based on the disaggregation of the seismic hazard for the region of interest. To identify their impact on structural performance, earthquake Intensity Measures, such as Peak Ground Acceleration and Peak Ground Velocity are examined for the case of a column that sustained no visible permanent deformations during the Ms = 6.5 Thessaloniki earthquake of 1978. The analysis revealed a weak correlation of PGA and PGV with the response results and a significant influence of the mean frequency (fm) of the seismic motion. No coupling was found between the maximum displacement of the top during the oscillation and the permanent post-seismic deformations. The complementarity of both earthquake Intensity Measures in the structural vulnerability assessment is also depicted
Seismic Vulnerability and Risk Assessment of Historic Constructions: The Case of Masonry and Adobe Churches in Italy and Chile
Nowadays, disasters in seismic-prone areas such as Italy and Chile, continue to cause dramatic human and economic consequences and affecting, among others, very ancient and historical churches, due to their high seismic vulnerability and probably due to the lack of risk management plans for the conservation of cultural property. This paper focuses on rapid seismic risk assessment by applying two simplified methods, based on expert judgement and observed damage, in old masonry churches, which aim to identify the most vulnerable elements and correlated threats that would act as site effects under the seismic action, for establishing intervention priority lists and for planning preventive conservation projects. The case studies are: the church of Sant’Agostino, built in stone masonry and located in Matera, an area with moderate seismicity in southern Italy; the church of San Francisco de Chiu Chiu, built in adobe and located in Calama, an area with average seismicity in the Andean northern Chile; and the church of San Francisco Barón, built in adobe and brick masonry, and located in Valparaíso, an area with high seismicity on the central coast of Chile
- …