Microstructural, optical and electrical investigations of Sb-SnO2 thin films deposited by spray pyrolysis

Electrical and optical properties of nitrogen doped SnO2 thin films deposited on flexible substrates by magnetron sputtering

Structural, morphological, optical and electrical properties of Sb-doped SnO 2 thin films obtained by aerosol assisted chemical vapor deposition

Indium tin oxide (ITO) thin films were prepared by electron beam evaporation at different substrate temperatures. The structural studies were carried out by X-ray diffraction. Optical properties of the films were studied in the ultraviolet-visible-near infrared (UV-Vis-NIR) region (200 to 2500 nm). Electrical studies were carried out at room temperature of ITO films. The results showed that with increase in substrate temperature, the optical transmittance gradually increased up to 93% in the visible region, the transmittance edge gradually shifted to short wavelength and the corresponding refractive index and thermal emissivity decreased. The structure of ITO films was polycrystalline and the crystallinity was improved with increasing substrate temperature. The electrical resistivity decreased and attained its minimum value of 5.2 × 10-4  W cm at 300°C.

	 

	Key words: Thin films, electron beam; indium tin oxide (ITO), optical constants, electrical properties, structure properties.

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Effect of substrate temperature on physical properties of In2O3:Sn films deposited by e-beam technique

Effect of magnesium and fluorine dopants on properties of ZnO thin films

Characterization of transparent conducting oxide thin films deposited on ceramic substrates

The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS) for pipe and vessels (PVP) application. For example, nuclear dry cask storage system (DCSS) is a safety-critical facility in need of monitoring over prolonged periods of time. Technologies for the diagnosis and prognosis of PVP systems can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure of a component.The past two decades have witnessed an extensive sensor technology development using permanently installed piezoelectric wafer active sensors (PWAS) for structural health monitoring (SHM). PWAS have emerged as one of the major SHM technologies developed particularly for generating and receiving acousto-ultrasonic waves for the purpose of continuous monitoring and diagnosis. Durability and survivability of PWAS under nuclear environmental exposures has been tested preliminarily. However, the analytical model of PWAS based sensor and sensing system has not been developed with adequate solutions and guideline. This paper presents a study on an analytical model of nuclear environmental effects with PWAS. Environmental variability of a Nuclear-SHM system includes changes in both the sensors and the sensing methodology including acoustic emission (AE), guided ultrasonic waves (GUW), and electro-mechanical impedance spectroscopy (EMIS). We considered the environmental variability considers the effects of temperature changes and radiation. We superposed these changes on the analytical models and determined how much the structural sensing signals change is due to these environment effects for the DCSS system. The analytical modeling of various structural sensing methods to environmental disturbances was studied and the potential of PWAS as irradiation sensors for PVP applications was explored. The paper ends with conclusions and suggestions for further work.© 2014 ASME

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Analytical Model of Nuclear Environmental Effects With Piezoelectric Wafer Active Sensors

Radioactive waste systems and structures (RWSS) are safety-critical facilities in need of monitoring over prolonged periods of time. Structural health monitoring (SHM) is an emerging technology that aims at monitoring the state of a structure through the use of networks of permanently mounted sensors. SHM technologies have been developed primarily within the aerospace and civil engineering communities. This paper addresses the issue of transitioning the SHM concept to the monitoring of RWSS and evaluates the opportunities and challenges associated with this process. Guided wave SHM technologies utilizing structurally-mounted piezoelectric wafer active sensors (PWAS) have a wide range of applications based on both propagating-wave and standing-wave methodologies. Hence, opportunities exist for transitioning these SHM technologies into RWSS monitoring. However, there exist certain special operational conditions specific to RWSS such as: radiation field, caustic environments, marine environments, and chemical, mechanical and thermal stressors. In order to address the high discharge of used nuclear fuel (UNF) and the limited space in the storage pools the U.S. the Department of Energy (DOE) has adopted a “Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste” (January 2013). This strategy endorses the key principles that underpin the Blue Ribbon Commission’s on America’s Nuclear Future recommendations to develop a sustainable program for deploying an integrated system capable of transporting, storing, and disposing of UNF and high-level radioactive waste from civilian nuclear power generation, defense, national security, and other activities. This will require research to develop monitoring, diagnosis, and prognosis tools that can aid to establish a strong technical basis for extended storage and transportation of UNF. Monitoring of such structures is critical for assuring the safety and security of the nation’s spent nuclear fuel until a national policy for closure of the nuclear fuel cycle is defined and implemented. In addition, such tools can provide invaluable and timely information for verification of the predicted mechanical performance of RWSS (e.g. concrete or steel barriers) during off-normal occurrence and accident events such as the tsunami and earthquake event that affected Fukushima Daiichi nuclear power plant. The ability to verify the conditions, health, and degradation behavior of RWSS over time by applying nondestructive testing (NDT) as well as development of nondestructive evaluation (NDE) tools for new degradation processes will become challenging. The paper discusses some of the challenges associated to verification and diagnosis for RWSS and identifies SHM technologies which are more readily available for transitioning into RWSS applications. Fundamental research objectives that should be considered for the transition of SHM technologies (e.g., radiation hardened piezoelectric materials) for RWSS applications are discussed. The paper ends with summary, conclusions, and suggestions for further work.Copyright © 2013 by ASME

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Adrián E. Méndez Torres

Papers

Characterization of transparent conducting oxide thin films deposited on ceramic substrates

Analytical Model of Nuclear Environmental Effects With Piezoelectric Wafer Active Sensors

Opportunities and challenges for structural health monitoring of radioactive waste systems and structures