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Generalized Plasticity Model for Nonlinear Analysis of Steel Frames at Elevated Temperatures
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A mathematical model of the formation of urine
No full textIn this work, a mathematical model of renal hemodynamics involved in urine production is studied. The model is formed by three sub-models: one corresponds to the glomerular filtration stage, which gives input to the blood that is processed in the kidney; another one is the corresponding to the renal autoregulation process which defines the blood flow that must enter the kidney, to maintain its correct functioning, even in the face of blood pressure variations; and the last sub-model corresponding to the reabsorption and secretion stages, the former corresponds to the process by which the kidneys recover useful substances from the glomerular filtrate and return them to the blood and in the latter the kidneys eliminate unwanted substances from the blood into the peritubular capillaries
Advances in the Characterisation of Sites Contaminated with Petroleum Hydrocarbons: Insights from a Collaborative Effort
Get PDFPetroleum hydrocarbons (PHCs) such as gasoline and diesel are among the most common and widespread contaminants in urban and industrial environments. The authors were engaged by the imprint Springer to complete a book giving visibility to technologies overcoming limitations associated with conventional characterisation approaches, as well as pertinent concepts and methods that may still be underutilised by the industry internationally. The open access book entitled ‘Advances in the characterisation and remediation of sites contaminated with petroleum hydrocarbons’ was prepared as a contributed volume involving the participation of more than 100 global experts from academia, government agencies, and the private sector. An analysis of the book contents yielded general insights into the state of the art regarding the investigation of PHC-impacted sites. As highlighted in several chapters, fate and transport of fuel products are controlled by multiphase flow mechanics and constitutive relations intrinsically linked to biological phenomena and the spatial and temporal variability of multiple subsurface properties. Most site characterization methods presented in the book (from direct-push vertical profiling and biogeophysics to sequence stratigraphy or molecular biological tools) address aspects often overlooked in conventional site investigation projects, including: (i) the entrapment of fuel products due to capillary forces, (ii) the essential role played by microbial activity, and (iii) subsurface heterogeneity effects. Further research and adoption of up-to-date concepts and methods are encouraged to ensure best practices are implemented and PHC risks are managed sustainably and responsibl
AI-Based Digitization of Legacy Ground Information
Get PDFGeotechnical characterization of site materials is of paramount importance in the construction and mining industry. The analysis of large volumes of geotechnical information from multiple sources leads to data-driven decisions that help to minimize uncertainty. For this purpose, a unified digital information platform becomes handy to have a global perspective and improve the analysis of available ground information data. Access to historic ground investigation data from previous projects during the project planning stage might increase efficiency. However, accessing and processing legacy data from companies’ databases is time and resources consuming. In the recent years, software tools that are capable of extracting data in a digital format from images have become popular, but still require human-supervised interpretation. A novel tool combining Optical Character Recognition (OCR), digital data extraction technologies and AI-based data interpretation system is presented herein. The state-of-the-art OCR technology is capable of accurately recognizing and extracting text from various document types, such as scanned documents, images, and PDFs. It utilizes advanced machine learning algorithms to process text, even in challenging conditions, ensuring data is extracted accurately and reliably. Then, a data interpretation system has been trained to identify the type of site characterization data and its structure while retrieving all the content in a digital format. All components work seamlessly together to provide a comprehensive solution for automating the interpretation and extraction of site characterization data, streamlining data management and analysis processes. The capability of gathering data from multiple sources in a unique ground information system provides valuable information for planning and design stages while decreasing costs, time and uncertainties. In addition, all these data are then available within DAARWIN platform to feed the ground model workflow
Post-liquefaction analysis and shear wave assessment by means of instrumented DCP: application to Cephalonia island (Greece) and Petrinja region (Croatia)
No full textThis work presents both a summary of its implementation at two post-seismic sites: the island of Cephalonia (Greece), and the Petrinja (Croatia) along the Kupa river. In the first case, the main objective was to characterize the surface formations of the Koutavos plio-quaternary sedimentary basin to propose a 1D model of the surface soil column and assess the influence of the variability of these surface formations on the amplification of seismic motion. The second experimental campaign in Croatia was aimed at identifying the soil layers that had been liquefied following the events of 2020, as well as highlighting the different soil models obtained by geophysics or constructed from instrumented variableenergy DCP. For each investigated site, additional geophysical and geotechnical tests were carried out. The data collected with this new technology were compared with those obtained previously with other geophysical methods (MASW), in order to assess the shear wave velocity obtained in particular
Material Subgrade Variability In Site Characterisation
Get PDFDelineation of areas into a “uniform” harvestable quality material is required for cut and fill earthworks projects. Mixing or inadvertent contamination with onsite high-quality material with adjacent poor quality is unacceptable. Importing material from off-site sources have significant cost associated. Two case studies are presented to highlight the design and contractual interpretation of a “unform” site. The first case study compares when a characteristic design value is used versus the day to day on site requirements to meet these design requirements. The required coefficient of variation (COV) of material parameters is discussed from both a design and construction perspective for section delineation. A major highway road widening had 4 sections as part of the upgrade. The tender documents were based on balanced cut to fill. On site material variability had pockets of good and bad material. Statistical analysis pre and post tender were compared in the contractual dispute which followed. The contractor was obligated to then import material to significant subgrade depths for these sites. To do otherwise would be contra to both the design material requirements specified in the contract documents and the requirements of the Earthworks specifications. The second case study is for a major 13 km rail upgrade to illustrate how the COV can be used in site characterisation and spatial variation at a cutting. The COV values adopted for both design and construction assessment are different as the intent is different. A quality control COV is different for a characteristic design COV
Types of Shearing and Anisotropy in Undrained CPTu
No full textMost natural clays acquire an anisotropic fabric upon deposition. This anisotropic fabric induces differences in the soil mechanical responses, for instance in the undrained shear strength observed in the laboratory. It is unclear how much of that anisotropy is reflected on the responses measured by the cone penetration test. In this work, we use GPFEM to numerically simulate cone penetration tests (CPTu) in undrained, anisotropic clays. The constitutive response is represented by S-CLAY1, a critical state, anisotropic model. Full details of the representative stress path during CPTu insertion are provided. Preliminary numerical results suggest that even a large amount of anisotropy, as described by the model, will have a very small effect on the cone responses. The numerical simulation results also show that the prevailing stress path has strong similitudes with that found during anisotropically-consolidated undrained compression triaxial test
Expansion test with one unload-reload loop and pore pressure measurement, first interpretation of dissipation tests, Larivot site
Get PDFThis paper presents an interpretation of cyclic pressuremeter tests with pore pressure measurement performed at Larivot bridge site (French Guyana). In cohesive soils, test results are in accordance with the pressuremeter theory. The times at 50% dissipation correlate closely with those obtained from dissipation tests performed using a piezocone in the immediate vicinity