An integrated computational approach for seismic risk assessment of individual buildings

The simultaneous assessment of a great number of buildings subjected to different ground motions is a very challenging task. For this reason, a new computational integrated approach for seismic assessment of individual buildings is presented, which consists of several independent computer objects, each having its own user interface, yet being totally interconnectable like in a puzzle. The hazard module allows considering a code-based response spectrum or a predicted response spectrum for a given earthquake scenario, which is computed throughout the resolution of an optimization problem. The vulnerability of each building is assessed based on structural capacity curves. Damage is evaluated using an innovative proposal, which is to use what was called a performance curve associated with a capacity curve. This curve reproduces the percentage of a given response spectrum corresponding to a performance point for each displacement value of a capacity curve. Therefore, it becomes possible to do a very fast association of any limit state to a percentage of a seismic action. This approach was implemented in the PERSISTAH software, and the result outputs can be exported, instantaneously, to the Google Earth software throughout the creation of a kml file, or to MS Excel.This research was funded by INTERREG-POCTEP España-Portugal program and the European Regional Development Fund, grant number 0313_PERSISTAH_5_P.info:eu-repo/semantics/publishedVersio

Stochastic Service Curve and Delay Bound Analysis: A Single Node Case

A packet-switched network node with constant capacity (in bps) is considered, where packets within each flow are served in the first in first out (FIFO) manner. While this single node system is perhaps the simplest computer communication system, its stochastic service curve characterization and independent case analysis in the context of stochastic network calculus (snetcal) are still basic and many crucial questions surprisingly remain open. Specifically, when the input is a single flow, what stochastic service curve and delay bound does the node provide? When the considered flow shares the node with another flow, what stochastic service curve and delay bound does the node provide to the considered flow, and if the two flows are independent, can this independence be made use of and how? The aim of this paper is to provide answers to these fundamental questions

Frequency scanning capaciflector for capacitively determining the material properties

A capaciflector sensor system scanned in frequency is used to detect the permittivity of the material of an object being sensed. A capaciflector sensor element, coupled to current-measuring voltage follower circuitry, is driven by a frequency swept oscillator and generates an output which corresponds to capacity as a function of the input frequency. This swept frequency information is fed into apparatus e.g. a digital computer for comparing the shape of the capacitance vs. frequency curve against characteristic capacitor vs. frequency curves for a variety of different materials which are stored, for example, in a digital memory of the computer or a database. Using a technique of pattern matching, a determination is made as to the identification of the material. Also, when desirable, the distance between the sensor and the object can be determined

Assessment of the Protective Capacity of Vadoze Zone over Aquifer Systems Using Secondary Geoelectrical Parameters: A Case Study Of Kaltungo Area North East, Nigeria

An assessment of the protective capacity of the vadose zone overlying the aquifer systems in the Kaltungo area was carried out to determine its influence on groundwater quality. Applying the schlumberger array with a maximum electrode spread AB/2 = 100m through VES, thirty water well points were surveyed using Omega terrameter (PIOSO1) resistivity meter. The field data was first subjected to manual interpretation through curve marching and then digitized modeled curves using computer software. The interpreted data revealed that the area is characterized by eleven different curve types representing three to five geo electrical layers. In order to assess the protective capacity of the vadoze zone over the aquifer systems, the longitudinal conductance (S) and transverse resistance (T) (secondary geoelectric parameters) were computed from the primary data using the Dar Zarouk formula. The values of S obtained range from 0.0018 to 0.4056 ohms with a mean value of 0.0135 ohms while the values of T range from 0.55 ohms to 1195.68 ohms with a mean value of 39.84 ohms. The values of S and T obtained reveal that 90% of probed points has poor protective capacity, 10 % has moderate protective capacity and 83 % has high transmissivity, 17 % has intermediate transmissivity. The T and S values are skewed towards poorly protective capacity thus making groundwater in the area highly vulnerable to contamination from the surface. To achieve good groundwater quality in the area, proper completion of newly constructed wells should install protective casing through the entire vadose zone

Mechanical response tissue analyzer for estimating bone strength

One of the major concerns for extended space flight is weakness of the long bones of the legs, composed primarily of cortical bone, that functions to provide mechanical support. The strength of cortical bone is due to its complex structure, described simplistically as cylinders of parallel osteons composed of layers of mineralized collagen. The reduced mechanical stresses during space flight or immobilization of bone on Earth reduces the mineral content, and changes the components of its matrix and structure so that its strength is reduced. Currently, the established clinical measures of bone strength are indirect. The measures are based on determinations of mineral density by means of radiography, photon absorptiometry, and quantitative computer tomography. While the mineral content of bone is essential to its strength, there is growing awareness of the limitations of the measurement as the sole predictor of fracture risk in metabolic bone diseases, especially limitations of the measurement as the sole predictor of fracture risk in metabolic bone diseases, especially osteoporosis. Other experimental methods in clinical trials that more directly evaluate the physical properties of bone, and do not require exposure to radiation, include ultrasound, acoustic emission, and low-frequency mechanical vibration. The last method can be considered a direct measure of the functional capacity of a long bone since it quantifies the mechanical response to a stimulus delivered directly to the bone. A low frequency vibration induces a response (impedance) curve with a minimum at the resonant frequency, that a few investigators use for the evaluation of the bone. An alternative approach, the method under consideration, is to use the response curve as the basis for determination of the bone bending stiffness EI (E is the intrinsic material property and I is the cross-sectional moment of inertia) and mass, fundamental mechanical properties of bone

Feasibility of using neural networks to obtain simplified capacity curves for seismic assessment

The selection of a given method for the seismic vulnerability assessment of buildings is mostly dependent on the scale of the analysis. Results obtained in large-scale studies are usually less accurate than the ones obtained in small-scale studies. In this paper a study about the feasibility of using Artificial Neural Networks (ANNs) to carry out fast and accurate large-scale seismic vulnerability studies has been presented. In the proposed approach, an ANN was used to obtain a simplified capacity curve of a building typology, in order to use the N2 method to assess the structural seismic behaviour, as presented in the Annex B of the Eurocode 8. Aiming to study the accuracy of the proposed approach, two ANNs with equal architectures were trained with a different number of vectors, trying to evaluate the ANN capacity to achieve good results in domains of the problem which are not well represented by the training vectors. The case study presented in this work allowed the conclusion that the ANN precision is very dependent on the amount of data used to train the ANN and demonstrated that it is possible to use ANN to obtain simplified capacity curves for seismic assessment purposes with high precision.info:eu-repo/semantics/publishedVersio

Investigation of New Hampshire hydropower potential

The popularity of green and renewable energy has risen sharply in recent years, and hydropower has consistently been the most common form of renewable energy in both the US and the state of New Hampshire. As a result of this strong green movement, government organizations have seen increased pressure to produce figures to the public detailing the amount of hydropower potentially available in the country. Often these figures will depict very attractive numbers for the untapped hydropower potential in the country, yet the data do not seem realistic to anyone familiar with hydropower generation. This paper will attempt to de-rate these general estimates made for hydropower potential by government organizations, specifically in New Hampshire. It will be determined if these parties are ignoring basic hydropower design challenges in their estimations, such as system efficiency, generator capacity factors, and the economic feasibility of the projects themselves. These results should reveal the inaccuracies (if any) of the estimates by the government groups. To analyze the general feasibility of hydropower projects in New Hampshire, three case studies in hydropower system design will be examined