Impact of deposit recoat cycle length on hot corrosion of CMSX-4

Hot corrosion causes significant problems for both aerospace and power generation industries, where the combination of high temperature, corrosive gases, and contaminants severely limits component operating lifetimes in gas turbine hot gas streams. Multiple laboratory testing methodologies exist to study this hot corrosion, and these can be affected by a range of variables. This paper investigated the impact of varying deposit recoat cycle length when using the ‘deposit recoat’ testing method. CMSX-4 samples were exposed to simulated type II (pitting) hot corrosion conditions, with the same overall deposit load (averaged across the total exposure run), but different deposit recoat cycles. Post-exposure, samples underwent dimensional metrology analysis to compare metal loss resulting from different deposit recoat cycle lengths. Results for CMSX-4 suggest very small differences in corrosion losses, indicating CMSX-4 hot corrosion datasets obtained from deposit recoat experiments with different deposit recoat cycle lengths can be compared with confidence

A Survey of Current Rotorcraft Propulsion Health Monitoring Technologies

A brief review is presented on the state-of-the-art in rotorcraft engine health monitoring technologies including summaries on current practices in the area of sensors, data acquisition, monitoring and analysis. Also, presented are guidelines for verification and validation of Health Usage Monitoring System (HUMS) and specifically for maintenance credits to extend part life. Finally, a number of new efforts in HUMS are summarized as well as lessons learned and future challenges. In particular, gaps are identified to supporting maintenance credits to extend rotorcraft engine part life. A number of data sources were consulted and include results from a survey from the HUMS community, Society of Automotive Engineers (SAE) documents, American Helicopter Society (AHS) papers, as well as references from Defence Science & Technology Organization (DSTO), Civil Aviation Authority (CAA), and Federal Aviation Administration (FAA)

Nitrous oxide metabolism in nitrate-reducing bacteria: Physiology and regulatory mechanisms

Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nit- ric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the appli- cation of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural effi- ciency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understand- ing of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation

Towards a gravitational wave observatory designer: sensitivity limits of spaceborne detectors

The most promising concept for low frequency (millihertz to hertz) gravitational wave observatories are laser interferometric detectors in space. It is usually assumed that the noise floor for such a detector is dominated by optical shot noise in the signal readout. For this to be true, a careful balance of mission parameters is crucial to keep all other parasitic disturbances below shot noise. We developed a web application that uses over 30 input parameters and considers many important technical noise sources and noise suppression techniques to derive a realistic position noise budget. It optimizes free parameters automatically and generates a detailed report on all individual noise contributions. Thus one can easily explore the entire parameter space and design a realistic gravitational wave observatory. In this document we describe the different parameters, present all underlying calculations, and compare the final observatory's sensitivity with astrophysical sources of gravitational waves. We use as an example parameters currently assumed to be likely applied to a space mission proposed to be launched in 2034 by the European Space Agency. The web application itself is publicly available on the Internet at http://spacegravity.org/designer. Future versions of the web application will incorporate the frequency dependence of different noise sources and include a more detailed model of the observatory's residual acceleration noise

Determination system of lubricant degradation based on digital image processing of oil spots in diesel engines

In any organization when you have plans of preventive and predictive maintenance is necessary to have tools to determine the status condition of the equipment, in the case of diesel engines are rapid tests that determine the state of the engine and lubricant, such as blotter spot test. In this paper we determine the characteristic parameters related to digital image processing of oil spots. Both instruments are developed basic procedures for taking samples of oil spot and images of these. Based on the interpretation of the oil spot given by experts and relations that estimate the dispersivity and the carbon content of the lubricant, more lab reports the sample population, we obtain a system that estimates the degradation of the lubricant.En cualquier organización cuando se tienen planes de mantenimiento preventivo y predictivo es necesario disponer de instrumentos para determinar el estado en condición de los equipos, en el caso de los motores diesel se tienen pruebas rápidas que determinan el estado del lubricante y del motor, como el ensayo de la mancha de aceite. En el presente trabajo se determinan los parámetros característicos relacionados con el tratamiento digital de imágenes de las manchas de aceite. Se elaboran tanto instrumentos como procedimientos básicos para la toma de muestras de manchas y de imágenes de estas. Tomando como base la interpretación de la mancha de aceite dada por los expertos y relaciones que permiten calcular la dispersividad y el contenido de carbonilla del lubricante, más los informes de laboratorio de la población muestra, se obtiene un sistema que estima la degradación del lubricante. &nbsp

Determination system of lubricant degradation based on digital image processing of oil spots in diesel engines

In any organization when you have plans of preventive and predictive maintenance is necessary to have tools to determine the status condition of the equipment, in the case of diesel engines are rapid tests that determine the state of the engine and lubricant, such as blotter spot test. In this paper we determine the characteristic parameters related to digital image processing of oil spots. Both instruments are developed basic procedures for taking samples of oil spot and images of these. Based on the interpretation of the oil spot given by experts and relations that estimate the dispersivity and the carbon content of the lubricant, more lab reports the sample population, we obtain a system that estimates the degradation of the lubricant.En cualquier organización cuando se tienen planes de mantenimiento preventivo y predictivo es necesario disponer de instrumentos para determinar el estado en condición de los equipos, en el caso de los motores diesel se tienen pruebas rápidas que determinan el estado del lubricante y del motor, como el ensayo de la mancha de aceite. En el presente trabajo se determinan los parámetros característicos relacionados con el tratamiento digital de imágenes de las manchas de aceite. Se elaboran tanto instrumentos como procedimientos básicos para la toma de muestras de manchas y de imágenes de estas. Tomando como base la interpretación de la mancha de aceite dada por los expertos y relaciones que permiten calcular la dispersividad y el contenido de carbonilla del lubricante, más los informes de laboratorio de la población muestra, se obtiene un sistema que estima la degradación del lubricante. &nbsp