pinecone/core-2020-05-10-deduplication huggingface dataset:
Response of tall buildings to weak long distance earthquakes

This is the peer reviewed version of the article, which has been published in final form at DOI 10.1002/eqe.32. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.In the last decade, two tall buildings in Singapore were instrumented with accelerometers and anemometers for the original purpose of identifying the characteristics and effects of wind loading. During the monitoring it became clear that the largest acceleration responses should result from ground motions due to earthquakes having magnitudes between 6 and 8 and epicentres at least 350 km distant. The paper describes the strategy for identifying and capturing the signals from distant tremors, which depends on tracking the RMS response levels in the second vibration mode. Characteristics of some recorded signals are given. While response levels are generally small, the frequency content coincides with the range of fundamental mode frequencies for high rise residential buildings. The validity of using a tall building as a ‘weak-motion’ seismograph is discussed by considering the mode shape of the building and the measured transfer function between basement and roof responses
Impulsive dirac-delta forces in the rocking motion

In this work the classical theory of one block rocking motion is revisited. A Dirac-delta type interaction
as impact mechanism is found to be an alternative for the traditional model. Numerical computations
with this new formulation have shown that the agreement with the classical theory is excellent for
the case of slender blocks and small displacements. Good agreement with experimental data has also
been found for the case of arbitrary angles and slenderness. A probabilistic study of the variations
in the coe cient of restitution due to the cyclic degradation at corners during seismic action is also
performed.
The approach presented in this paper opens new lines for further theoretical developments and
computational applications
Ambient vibration survey of the Bosporus Suspension Bridge

This is the peer reviewed version of the article, which has been published in final form at DOI 10.1002/eqe.4290180210. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Traffic and wind excitation has been used to obtain the dynamic characteristics of the first Bosporus (Bogazici) Suspension Bridge. Structural symmetry and the absence of suspended side-spans allowed attention to be focused on the main span and the Asian tower. For the main span, 18 vertical and 20 lateral modes were obtained, including torsional modes. For the tower, 12 longitudinal and 12 lateral modes were identified. All these models lie in the range 0–1-1 Hz.

A detailed comparison is given between these modes and corresponding calculated modes, obtained by use of a three-dimensional finite element model which includes a geometric stiffness matrix. Of particular interest is the validity of the theoretical model used for the box-deck, because of its subsequent use in response studies of asynchronous seismic excitation.

Comparison with a more limited study made in 1973 shows that the bridge continues to behave as it was designed to behave, particularly with regard to the deck-tower interface. From natural frequency measurements of two hangers, the load which they carry was assessed
Effects of infill walls and floor diaphragms on the dynamic characteristics of a narrow-rectangle building

This is the peer reviewed version of the following article: Pan, T.-C., You, X. and Brownjohn, J. M. W. (2006), Effects of infill walls and floor diaphragms on the dynamic characteristics of a narrow-rectangle building. Earthquake Engineering and Structural Dynamics, 35: 637–651. .which has been published in final form at: doi:10.1002/eqe.550Most buildings in Singapore are lightly reinforced concrete structures which are manly
designed for gravity loading only, because Singapore is an island country located in a low
to moderate seismic region. The dynamic properties of a typical high-rise residential
building with a long, narrow rectangular floor plan are studied using both experimental and
numerical methods. The effects of the brick infill walls and the flexible diaphragms on the
dynamic characteristics of the building are discussed in detail. The results from the ambient
vibration tests are correlated with the numerical results of three different finite element
models with different levels of sophistication. They include a bare frame model, a frame
model with brick infill walls, and a frame model with both brick infill walls and flexible
diaphragms. The dynamic properties of the third model match very well with the measured
results in terms of both the natural frequencies and the mode shapes. The correlation results demonstrate the respective effects of the brick infill walls and the flexible diaphragms on
the dynamic characteristics of the narrow-rectangle building structure
Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildings

The feasibility and efficiency of a seismic retrofit solution for existing reinforced concrete frame systems, designed before the introduction of modern seismic-oriented design codes in the mid 1970s, is conceptually presented and experimentally investigated. A diagonal metallic haunch system is introduced at the beam-column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms, while inverting the hierarchy of strength within the beam-column subassemblies and forming a plastic hinge in the beam. A complete step-by-step design procedure is suggested for the proposed retrofit strategy to achieve the desired reversal of strength hierarchy. Analytical formulations of the internal force flow at the beam-column-joint level are derived for the retrofitted joints. The study is particularly focused on exterior beam-column joints, since it is recognized that they are the most vulnerable, due to their lack of a reliable joint shear transfer mechanism. Results from an experimental program carried out to validate the concept and the design procedure are also presented. The program consisted of quasi-static cyclic tests on four exterior,  scaled, beam-column joint subassemblies, typical of pre-1970 construction practice using plain round bars with end-hooks, with limited joint transverse reinforcement and detailed without capacity design considerations. The first (control specimen) emulated the as-built connection while the three others incorporated the proposed retrofitted configurations. The experimental results demonstrated the effectiveness of the proposed solution for upgrading non-seismically designed RC frames and also confirmed the applicability of the proposed design procedure and of the analytical derivations
On the dynamics of rocking motion of single rigid–block structures

This paper describes the behavior of single rigid-block structures under dynamic loading. A comprehensive
experimental investigation has been carried out to study the rocking response of four blue granite stones
with different geometrical characteristics under free vibration, and harmonic and random motions of the
base. In total, 275 tests on a shaking table were carried out in order to address the issues of repeatability of
the results and stability of the rocking motion response. Two different tools for the numerical simulations
of the rocking motion of rigid blocks are considered. The first tool is analytical and overcomes the usual
limitations of the traditional piecewise equations of motion through a Lagrangian formalism. The second
tool is based on the discrete element method (DEM), especially effective for the numerical modeling
of rigid blocks. A new methodology is proposed for finding the parameters of the DEM by using the
parameters of the classical theory. An extensive comparison between numerical and experimental data
has been carried out to validate and define the limitations of the analytical tools under study.Ecoleader Group 4Fundação para a Ciência e a Tecnologia (FCT) -: SFRH/BPD/17449/2004, SFRH/BD/9014/200
A distributed shear and flexural flexibility model with shear-flexure interaction for R/C members subjected to seismic loading

Α beam-column type finite element for seismic assessment of R/C frame structures is presented. This finite element consists of two interacting, distributed flexibility subelements representing inelastic flexural and shear response. Following this formulation, the proposed model is able to capture spread of flexural yielding, as well as spread of shear cracking, in R/C members. The model accounts for shear strength degradation with inelastic curvature demand, as well as coupling between inelastic flexural and shear deformations after flexural yielding, observed in many experimental studies. An empirical relationship is proposed for evaluating average shear distortion of R/C columns at onset of stirrup yielding. The proposed numerical model is validated against experimental results involving R/C columns subjected to cyclic loading. It is shown that the model can predict well the hysteretic response of R/C columns with different failure modes, i.e. flexure-critical elements, elements failing in shear after flexural yielding, and shear-critical R/C members
Dimensional analysis of the earthquake-induced pounding between adjacent structures

In this paper the dynamic response of two and three pounding oscillators subjected to pulse-type excitations is revisited with dimensional analysis. Using Buckingham's Π-theorem the number of variables that govern the response of the system is reduced by three. When the response is presented in the dimensionless Π-terms remarkable order emerges. It is shown that regardless of the acceleration level and duration of the pulse all response spectra become self-similar and follow a single master curve. This is true despite the realization of finite duration contacts with increasing durations as the excitation level increases. All physically realizable contacts (impacts, continuous contacts, and detachments) are captured via a linear complementarity approach. The study confirms the existence of three spectral regions. The response of the most flexible among the two oscillators amplifies in the low range of the frequency spectrum (flexible structures); whereas, the response of the most stiff among the two oscillators amplifies at the upper range of the frequency spectrum (stiff structures). Most importantly, the study shows that pounding structures such as colliding buildings or interacting bridge segments may be most vulnerable for excitations with frequencies very different from their natural eigenfrequencies. Finally, by applying the concept of intermediate asymptotics, the study unveils that the dimensionless response of two pounding oscillators follows a scaling law with respect to the mass ratio, or in mathematical terms, that the response exhibits an incomplete self-similarity or self-similarity of the second kind with respect to the mass ratio
Experimental and numerical investigation of thermal energy storage with a finned tube

A latent heat thermal energy storage system using a phase change material (PCM) is an efficient way of storing or releasing a large amount of heat during melting or solidification. It has been determined that the shell-and-tube type heat exchanger is the most promising device as a latent heat system that requires high efficiency for a minimum volume. In this type of heat exchanger, the PCM fills the annular shell space around the finned tube while the heat transfer fluid flows within the tube. One of the methods used for increasing the rate of energy sto rage is to increase the heat transfer surface area by employing finned surfaces. In this study, energy storage by phase change around a radially finned tube is investigated numerically and experimentally. The solution of the system consists of the solving governing equations for the heat transfer fluid (HTF), pipe wall and phase change material. Numerical simulations are performed to investigate the effect of several fin parameters (fin spacing and fin diameter) and flow parameter (Re number and inlet temperature of HTF) and compare with experimental results. The effect of each variable on energy storage and amount of solidification are presented graphically.Natural Science Foundation of Dokuz Eylül Universities: No: 02.KB.FEN.02
Artificial neural networks applications in building energy predictions and a case study for tropical climates

This study presents artificial neural network (ANN) methods in building energy use predictions. Applications of the ANN methods in energy audits and energy savings predictions due to building retrofits are emphasized. A generalized ANN model that can be applied to any building type with minor modifications would be a very useful tool for building engineers. ANN methods offer faster learning time, simplicity in analysis and adaptability to seasonal climate variations and changes in the building's energy use when compared to other statistical and simulation models. The model herein is presented for predicting chiller plant energy use in tropical climates with small seasonal and daily variations. It was successfully created based on both climatic and chiller data. The average absolute training error for the model was 9.7% while the testing error was 10.0%. This indicates that the model can successfully predict the particular chiller energy consumption in a tropical climate
Wind speed time series chacacterization hy Hilbert transform

Predictions of wind energy potential in a given region are based on on-location observations. The time series of these observations would later be analysed and modelled either by a probability density function (pdf) such as a Weibull curve to represent the data or recently by soft computing techniques, such as neural networks (NNs). In this paper, discrete Hilbert transform has been applied to characterize the wind sample data measured on Izmir Institute of Technology campus area which is located in Urla, Izmir, Turkey, in March 2001 and 2002. By applying discrete Hilbert transform filter, the instantaneous amplitude, phase and frequency are found, and characterization of wind speed is acomplished. Authors have also tried to estimate the hourly wind data using daily sequence by Hilbert transform technique. Results are varying
A renewable energy and hydrogen scenario for northern Europe

A scenario based entirely on renewable energy with possible use of hydrogen as an energy carrier is constructed for a group of North European countries. Temporal simulation of the demand-supply matching is carried out for various system configurations. The role of hydrogen technologies for energy storage and fuel cell applications is studied and applied to both stationary energy use and transportation sectors. As an alternative, biofuels may take the role of hydrogen both as a storable fuel and for direct use in the transportation sector. It is shown that there is scope for considerable amounts of energy trade between the countries, due to the different endowments of different countries with particular renewable energy sources, and to the particular benefit that intermittent energy sources, such as wind and solar, can derive from exchange of power. The establishment of a smoothly functioning renewable energy supply system is demonstrated with the use of the seasonal reservoir-based hydrocomponents in the northern parts of the region. The outcome of the competition between biofuels and hydrogen in the transportation sector is dependent on the development of viable fuel cells and on efficient technologies for converting biomass residues to fuels. Copyright © 2007 John Wiley & Sons, LtdPublished Online: 28 Nov 200
Potential applications using LNG cold energy in Sicily

According to previsions, natural gas could be the main energy source worldwide, inducing relevant geopolitical
changes. Most likely, such problems will be solved with the development of a gas transportation mode alternative to
traditional pipelines: liquefied natural gas (LNG). The global LNG trade has increased rapidly during recent years. A
significant amount of energy is consumed to produce low-temperature LNG, which has plenty of cryogenic exergy/
energy. Therefore, the effective utilization of the cryogenic energy associated with LNG vaporization is very important.
Sicily, with more than five million inhabitants, is the second biggest region of Italy and in this region will be realized two
of the 11 gasification plants planned in Italy according to the regional energy master-plan. This paper shows some
interesting applications for the cold produced in gasification plants, e.g. for seawater desalination and for fresh and
frozen food production and conservation. These applications seem very interesting for Sicilian situation and also can
contribute to energy saving and greenhouse gases reduction to match Kyoto Protocol targets. Copyright # 2008 John
Wiley & Sons, Ltd
Thermodynamic analysis of two-step solar water splitting with mixed iron oxides

A two-step thermochemical cycle for solar production of hydrogen from water has been developed and investigated. It\ud
is based on metal oxide redox pair systems, which can split water molecules by abstracting oxygen atoms and reversibly\ud
incorporating them into their lattice. After successful  experimental demonstration of several cycles of alternating\ud
hydrogen and oxygen production, the present work describes a thermodynamic study aiming at the improvement of\ud
process conditions and at the evaluation of the theoretical potential of the process.\ud
In order to evaluate the maximum hydrogen production potential of a coating material, theoretical considerations\ud
based on thermodynamic laws and properties are useful and faster than actual tests. Through thermodynamic calculations it is possible to predict the theoretical maximum output of H2 from a specific redox-material under certain conditions. Calculations were focussed on the two mixed iron oxides nickel–iron-oxide and zinc–iron-oxide. In the simulation the amount of oxygen in the redox-material is calculated before and after the water-splitting step on the basis of laws of thermodynamics and available material properties for the chosen mixed iron oxides. For the simulation the commercial Software FactSage and available databases for the required material properties were used.\ud
The analysis showed that a maximum hydrogen yield is achieved if the reduction temperature is raised to the limits of\ud
the operation range, if the temperature for the water splitting is lowered below 8001C and if the partial pressure of oxygen during reduction is decreased to the lower limits of the operational range. The predicted effects of reduction temperature and partial pressure of oxygen could be confirmed in experimental studies. The increased hydrogen yield at lower splitting temperatures of about 8001C could not be confirmed in experimental results, where a higher splitting\ud
temperature led to a higher hydrogen yield. As a consequence it can be stated that kinetics must play an important role especially in the splitting step
Modeling of a solar receiver–reactor for sulfur-based thermochemical cycles for hydrogen generation

Sulfur based thermochemical cycles for hydrogen generation from water have one reaction step in common which is the decomposition of sulfuric acid as one of the most energy consuming steps. The present work deals with the development of a dynamic mathematical model of a solar reactor. for this key step. One of the core parts of the model is a part model of the reaction kinetics of the decomposition of sulfur trioxide, which is based on experiments investigating the kinetics of the used catalyst platinum coated on a ceramic solar absorber. Other part models describe e. g. the absorption of solar radiation, heat conduction in the absorber, convection between gas and the absorber walls and energy losses due to heat radiation.\ud
A comprehensive validation of the reactor model is performed using measured data which is gained in experiments with a prototype reactor. The operating behavior of the real reactor is compared with the results of the numerical simulation with the model. The validation is in particular done by reproducing the influences of individual parameters on the chemical conversion and the reactor efficiency. The relative deviations between experimental data and simulation results are mostly within the range of measurement accuracy. In particular the good agreement of calculated values of the derived parameters SO3 conversion and reactor efficiency with those determined from the experiments qualify the model for optimization purposes
Thermodynamic optimisation of the integrated design of a small‐scale solar thermal Brayton cycle

The Brayton cycle’s heat source does not need to be from combustion but can be extracted from solar energy. When a
black cavity receiver is mounted at the focus of a parabolic dish concentrator, the reflected light is absorbed and converted
into a heat source. The second law of thermodynamics and entropy generation minimisation are applied to optimise the
geometries of the recuperator and receiver. The irreversibilities in the recuperative solar thermal Brayton cycle are mainly
due to heat transfer across a finite temperature difference and fluid friction. In a small‐scale open and direct solar thermal
Brayton cycle with a micro‐turbine operating at its highest compressor efficiency, the geometries of a cavity receiver and
counterflow‐plated recuperator can be optimised in such a way that the system produces maximum net power output. A
modified cavity receiver is used in the analysis, and parabolic dish concentrator diameters of 6 to 18m are considered. Two
cavity construction methods are compared. Results show that the maximum thermal efficiency of the system is a function
of the solar concentrator diameter and choice of micro‐turbine. The optimum receiver tube diameter is relatively large
when compared with the receiver size. The optimum recuperator channel aspect ratio for the highest maximum net power
output of a micro‐turbine is a linear function of the system mass flow rate for a constant recuperator height. For a system
operating at a relatively small mass flow rate, with a specific concentrator size, the optimum recuperator length is small.
For the systems with the highest maximum net power output, the irreversibilities are spread throughout the system in such
a way that the internal irreversibility rate is almost three times the external irreversibility rate.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-114X