Search results for "INVESTIGATION"
showing 10 items of 366 documents
DNA Evidence Uncompromised by Active Oxygen
2010
Currently, forensic sciences can make use of the potential of instrumental analysis techniques to obtain information from the smallest, even invisible, samples. However, as laboratory techniques improve, so too should the procedures applied in the search for and initial testing of clues in order to be equally effective. This requires continuous revision so that those procedures may resolve the problems that samples present. As far as bloodstains are concerned, there are methods available that are recognized as being both highly sensitive and effective. Nevertheless, the marketing of new cleaning products, those that contain active oxygen, has raised doubts about the ability of those procedu…
Split decomposition A technique to analyze viral evolution
1993
A clustering technique allowing a restricted amount of overlapping and based on an abstract theory of coherent decompositions of finite metrics is used to analyze the evolution of foot-and-mouth disease viruses. The emerging picture is compatible with the existence of viral populations with a quasispecies structure and illustrates various forms of evolution of this virus family. In addition, it allows the correlation of these forms with geographic occurrence.
Experimental test results vs. analytical prediction of welded joint strength in hybrid steel trussed concrete beams (HSTCBs)
2013
The aim of the paper is to provide practical guidelines for the design of welded joints of steel truss for encased composite steel–concrete beams. The results of experimental tests are presented and interpreted. The steel truss is made of a steel plate acting as the bottom chord, made of S355 structural steel, coupled with steel rebars which form the upper chord, and steel inclined web rebars (V-reverse) welded to the two chord elements, both of them made of steel B450C. Butt welded joints of web bar to bottom steel plate and fillet welding joints of inclined web bars to top chord bars were tested, as they are different from the ones which are normally used due to the coupling of different …
Experimental validation of a direct pre-design formula for TLCD
2014
The passive control of vibrations has received in recent years a great deal of attention from researchers. Several types of devices have been proposed in order to reduce the dynamic responses of different kinds of structural systems. Among them, the Tuned Liquid Column Damper (TLCD) has proved to be very effective in reducing vibration of structures. However, since the equations governing the TLCD controlled systems response is nonlinear, the calibration of TLCD parameters is time consuming and not convenient to perform in a pre-design phase. In this context, it has recently been introduced by the authors a formula that allows to choose the optimal parameters of TLCD in a direct and fast wa…
Innovative modeling of tuned liquid column damper controlled structures
2016
In this paper a different formulation for the response of structural systems controlled by Tuned Liquid Column Damper (TLCD) devices is developed, based on the mathematical tool of fractional calculus. Although the increasing use of these devices for structural vibration control, it has been demonstrated that existing model may lead to inaccurate prediction of liquid motion, thus reflecting in a possible imprecise description of the structural response. For this reason the recently proposed fractional formulation introduced to model liquid displacements in TLCD devices, is here extended to deal with TLCD controlled structures under base excitations. As demonstrated through an extensive expe…
Combining TMD and TLCD: analytical and experimental studies
2017
Abstract In these years several research efforts have been focused on developing efficient and reliable control devices for mitigating the structural response of tall and lightly damped buildings in case of strong dynamic excitations, such as wind and earthquake ones. In this context, Tuned Mass Dampers (TMDs) represent probably the most common control device due to their high control performances. On the other hand, Tuned Liquid Column Dampers (TLCDs) are increasingly becoming more popular because of some of their attractive features, cost-effectiveness among the others, even though they yield slightly less control performance compared to the classical TMDs. Aiming at combining the benefic…
Towards more equity concerning quality of Urban Waste Management services in the context of cities
2018
Abstract An innovative combined evaluation approach is proposed in the present paper to deal with the issue of the performance measurement and comparison of Urban Waste Management (UWM) services in the context of cities. The ELECTRE III method is initially considered as tool able to execute a multi-criteria analysis aimed at ranking UWM systems based on their integration and sustainability levels. The latter are comprehensively evaluated via the recently developed “Wasteaware” Integrated and Sustainability Waste Management indicators framework, which takes into account physical components and governance aspects of UWM systems. Then, on the basis on ELECTRE III results, a practical gaps inve…
Effects of electrical and mechanical parameters on the transient voltage stability of a fixed speed wind turbine
2011
Abstract In this paper the dynamic behaviour of a wind turbine connected to the grid is examined. The model of the fixed speed wind turbine has been developed with the Simulink simulation tool (Matlab Inc.) It is composed of the induction generator, the shaft system, an aerodynamic model of the wind turbine rotor and the pitch control system. Using this model, a three-phase fault is applied close to the wind turbine and cleared by disconnecting the faulty line. The rigorous implementation of the simulink model allowed the authors to evaluate the exact dependence of various electrical parameters for the induction generator on voltage stability. Furthermore, the effects of wind turbine mechan…
Wind Turbine Mechanical Characteristics and Grid Parameters Influence on the Transient Voltage Stability of a Fixed Speed Wind Turbine
2008
This paper describes the effect of wind turbine mechanical characteristic of construction and grid parameters on the transient voltage stability of a fixed speed wind turbine (FSWT) connected to a simple grid. The model of FSWT has been developed in Matlab/Simulink. Using this model, a three-phase fault is applied close to the wind turbine (WT) and cleared by disconnecting the faulted line. The effects of mechanical construction of WT and of grid parameters on the voltage stability of this simple case are evaluated and discussed. The considered parameters are the inertia coefficient of the WT, the short-circuit power at the connection bus, the hub-generator resonant frequency, the wind spee…
Effects of Electrical Parameters of Induction Generator on the Transient Voltage Stability of a Fixed Speed Wind Turbine
2008
This paper describes the effect of electrical parameters of the induction generator on the transient voltage stability of a fixed speed wind turbine connected to a simple grid; the dynamic behavior of a wind turbine connected to the grid is examined. The model of the fixed speed wind turbine has been developed in the simulation tool Matlab/Simulink. Itpsilas composed by the induction generator, the shaft system, the aerodynamic model of the wind turbine rotor and the pitch control system. Using this model, a three-phases fault is applied close to the wind turbine and cleared by disconnecting the faulted line. The effect of different electrical parameters of the induction generator on the vo…