Voltage sags are short duration of voltage reduction caused by system faults, overloads and starting of large motors. Voltage sags are the main causes of trips of various sensitive equipment. In order to understand the voltage-tolerance performance of some process control equipment, this thesis presents test results of some sensitive equipment (such as computers, AC contactors, high intensity discharge lamps and programmable logic controller) and provides their voltage tolerance curves. A number of magnitudes and durations recommended by IEC 61000- 4- 11 are used to perform the tests. With the performance information in hands, power quality requirements of different types of equipment and customer, and area of vulnerability for sensitive loads could be estimated.

Adjustable-speed drives (ASDs) are often used in commercial and industrial facilities to improve process control and save energy. However, ASDs are the sensitive load equipment as regards to voltage sag. During the sag, the dc-bus capacitor of a typical ASD will discharge depending on the loading condition. The voltage of the dc bus decreases and could lead to a trip of the device. In order to understand the voltage sag tolerance capability of ASDs. Based on IEC 61800-3 and IEC 61000-4-11, this research presents the test results of ASD subjected to voltage sags under different operating conditions. The tests focus on different types of voltage sags, operating situations and designs of ASDs.

Solvent extraction is one of the methods available for the decontamination of sensitive equipments that are contaminated with chemical warfare agents. The efficiency of extraction method have been verified on the samples, (steel or rubber) that have been contaminated with drops of mustard gas. These samples have been inserted into the extraction flow cell through which solvent (ethoxynonafluorobutane - HFE-7200) flowed. The solvent was sampled in the time intervals. These samples of solvent were analysed for the concentration of mustard gas. Process of extraction was monitored for the three operational factors (the solvent flow rate, temperature and the ultrasound power) and for three different situations (dissolution of drops of mustard gas, mustard gas desorption from the structure of the sample and dissolve drops of mustard gas with the subsequent desorption from the sample). The development of the decontamination process in time was found to consist of two stages. In the first stage the rapid dissolution of the liquid part of mustard gas in a solvent and in the second phase was such as mustard desorption from the structure of the sample and this phase was considerably slower. Extraction is to accelerate increasing the value of the flow of the solvent, the temperature and the performance of the ultrasound. These operational fac-tors have a significant impact on the thickness of the laminar layer of solvent, the solvent replacement coefficient in a cell, diffusion parameters in the process, the viscosity, the solubility of mustard gas in a solvent and the maximum achievable concentration of mustard gas in the rubber sample. The values of adjustable parameters was obtained by mathematical analysis of mathematical model. The progress of extraction under different operational conditions can be predicted by these parameters. The effect of solvents and ultrasound was experimentally verified for selected equipments of computing and communication technology. The possibility of separation of chemical warfare agents from the solvent was verified too.

Basado en la idea de reducir la demanda sísmica en lugar de aumentar la capacidad resistente de las estructuras, el aislamiento sísmico es un método simple para mitigar o reducir los posibles daños producidos por los terremotos. La correcta aplicación de esta tecnología conduce a un mejor comportamiento de las estructuras, que sigue siendo esencialmente elástico durante los terremotos de gran magnitud. El núcleo de esta tecnología es el aislador. La mayoría de los aisladores sísmicos disponibles en la actualidad siguen teniendo limitaciones prácticas que impiden que funcionen según lo previsto e imponen restricciones a su uso efectivo y al nivel de protección proporcionado. En esta Tesis, se presenta un aislador sísmico avanzado llamado "roll-n-cage (RNC)". Se propone investigar su eficiencia a través de simulación numérica, en un intento de crear un sistema de aislamiento sísmico práctico, efectivo y económico, que tiene por objeto resolver los principales inconvenientes de los actuales sistemas de aislamiento sísmico, manteniendo sus principales ventajas. Este aislador incorpora aislamiento, disipación de energía, amortiguamiento y capacidad de fuerza recuperadora en una sola unidad. Además, ofrece una resistencia al viento significativa y una amplia gama de flexibilidad horizontal, por lo que es adecuado para proteger las estructuras de masa ligera, moderada y grande, así como para proteger equipos sensibles, hardware y / o antigüedades alojados en edificios. Por otra parte, las cuestiones relativas a la viabilidad, los costes de construcción y la disponibilidad de materiales, reducción o prevención de las respuestas de torsión y la resistencia a la elevación son abordados a fondo durante el diseño del aislador RNC. El aislador RNC propuesto es descrito en profundidad y sus principios de funcionamiento son presentados en detalle. La caracterización mecánica del dispositivo se ha llevado a cabo por medio de un código computacional sofisticado que simula la respuesta de los dispositivos como si estuvieran sujetos a una máquina de pruebas reales. A través de este esquema, se consigue analizar numéricamente el comportamiento del aislador RNC bajo el efecto simultáneo de cargas horizontales y verticales, como se da típicamente en situaciones prácticas. Además, se presenta una descripción matemática de las principales características asociadas a la rodadura de los aisladores RNC. Asimismo se obtiene un modelo matemático para describir en una forma razonable y manejable la relación fuerza desplazamiento exhibida por el aislador de RNC. Para evaluar la viabilidad del aislador RNC y para comprobar su capacidad para proteger los sistemas estructurales y no estructurales de los riesgos sísmicos, el dispositivo se implementa numéricamente en una variedad de estructuras con masas ligeras y grandes, además de en equipos sensibles alojados en los pisos superiores de dichas estructuras. Para extraer conclusiones de carácter relativamente general sobre el funcionamiento del aislador RNC, se estudia una amplia gama de terremotos y de características y propiedades de los aisladores y de las estructuras.Los resultados numéricos revelan que el aislador RNC propuesto puede reducir la respuesta sísmica frente a un amplio rango de excitaciones sísmicas, mientras que exhibe un rendimiento robusto para una gran variedad de estructuras. La Tesis incluye como apéndice un estudio en profundidad sobre el modelo de histéresis de Bouc-Wen. El estudio contiene una revisión de los primeros y últimos avances y aplicaciones de este modelo, que es ampliamente utilizado en la descripción de fenómenos de histéresis en las estructuras. / Based on the concept of reducing seismic demand rather than increasing the earthquake resistant capacity of structures, seismic isolation is a surprisingly simple approach to mitigate or reduce earthquake damage potential. Proper application of this complex technology leads to better performing structures that will remain essentially elastic during large earthquakes. The core of this technology is the isolator. Most currently available seismic isolators still have practical limitations causing them not to function as anticipated and impose restrictions to their proper use and to the provided protection level. In this dissertation, an advanced rolling-based seismic isolator, named roll-n-cage (RNC) isolator, is proposed and investigated via numerical simulation as an attempt to create a practical, effective, and economic seismic isolation system that aims to fix the main drawbacks of the current seismic isolation systems while keeping their main advantages. This isolator incorporates isolation, energy dissipation, buffer and restoring force mechanisms in a single unit. Further, it offers a significant wind resistance and a great range of horizontal flexibility making it ideal to protect light, moderate and heavy mass structures as well as precious housed motion-sensitive equipment, hardware and/or antiquities. Moreover, issues related to practicality, construction costs and material availability, reducing or preventing torsional responses and uplift resistance are thoroughly addressed during the RNC bearing design.The proposed RNC isolator is deeply described and its principles of operation are extensively highlighted. The mechanical characterization of the device has been carried out by means of a sophisticated computer code in a machine-like environment, which accurately simulates the response of the device subjected to a real testing machine. Through this machine-like environment, a general scheme is followed to numerically examine the behavior of the RNC isolator under simultaneous horizontal and vertical loads as in typical practical situations. Further, a mathematical description of the main features associated to rolling of the RNC isolator is presented. An input-output mathematical model is obtained to describe in a reasonable and manageable form the force-displacement relationship exhibited by the RNC isolator.To assess the feasibility of the RNC isolator and to check its ability to protect structural and nonstructural systems from seismic hazards, it is numerically implemented to a variety of structures having light to heavy masses, in addition to motion-sensitive equipment housed in upper building floors. Further, and to draw relatively general conclusions about the performance of the RNC isolator, a wide range of ground motions, isolator characteristics and structural properties is considered. The numerical results reveal that the proposed RNC isolation bearing can mitigate the seismic responses under a variety of ground motion excitations while exhibiting robust performance for a wide range of structures. The dissertation is appended with an in-depth survey, that contains a review of the past, recent developments and implementations of the versatile Bouc-Wen model of smooth hysteresis, which is used extensively in modeling the hysteresis phenomenon in the dynamically excited nonlinear structures. This survey is the first of its kind about the model since its origination more than 30 years ago. The objective is to present some of the popular approaches that have utilized and/or developed that model to capture the hysteretic behavior offered by a variety of nonlinear systems. Then, the evaluation of their results and contributions (if any) is carried out to highlight their assets and limitations and to identify future directions in this research area.