ALBERT

Description: The development of this paper was inspired by the increase in the number of different eco-label like quality assurance schemes established in the European Union in the past few years. These schemes are flooding the market and the researchers raise the question, is there enough credibility in these schemes? This piece of research is based on 58 eco-labeling like food schemes and dissects them into the building blocks of the different factors that makes a scheme credible and analyses the structure of these blocks as well as a literature survey on the perceptions of both the consumers and producers to these schemes. The sort of credibility structure that the building blocks of the schemes (ownership, stakeholder dialogue, traceability, transparency, etc.) have created was discussed and it was questioned if they meet the expectations of the consumers. The main findings of the research indicate that although small groups of consumers may be satisfied with a number of the different schemes, the majority of them fall short of providing a credible quality assurance scheme. Improvements were suggested such as involving a more diverse range of stakeholders and expanding the responsibility of processors and retailers. An alternative to the current form of labeling is also discussed.

Description: Selbstverständlich schafft Windenergie Arbeitsplätze. Betrachtet man die Studie des Bremer Energie-Institutes näher, so zeigen sich einige methodische Schwächen und wenig plausible Annahmen. Von einer "nüchternen Analyse" kann deswegen nicht gesprochen werden.

Description: New energy efficiency policies have been introduced around the world. Historically, most energy models were reasonably equipped to assess the impact of classical policies, such as a subsidy or change in taxation. However, these tools are often insufficient to assess the impact of alternative policy instruments. We evaluate the so-called engineering economic models used to assess future industrial energy use. Engineering economic models include the level of detail commonly needed to model the new types of policies considered. We explore approaches to improve the realism and policy relevance of engineering economic modeling frameworks. We also explore solutions to strengthen the policy usefulness of engineering economic analysis that can be built from a framework of multidisciplinary cooperation. The review discusses the main modeling approaches currently used and evaluates the weaknesses in current models. We focus on the needs to further improve the models. We identify research priorities for the modeling framework, technology representation in models, policy evaluation, and modeling of decision-making behavior.

Description: This book presents important new research on applied eco-efficiency concepts throughout Europe. The aim of eco-efficiency is to achieve market-based measures of environmental protection, in order to enhance the prospects for sustainable development and achieve positive economic and ecological benefits. The distinguished authors discuss a number of themes surrounding eco-efficiency including the necessary conditions for technological dissemination and ecological modernization, and the role of government in enabling businesses and society to participate actively in this process. In particular, they highlight the application of existing European-based policies concerning material flows and energy. The authors also investigate some new concepts of sustainable development and provide a useful introduction to material flows analysis. In further chapters they study the emerging regulatory policies for eco-efficiency, and examine the issues of sustainable business and consumption strategies.

Description: Transnational corporations' (TNCs) economic operations cover numerous countries and can be diverted between several continents. These units have reached a level of significance, having not only economic, but also social and environmental implications. This justifies that they shall be treated separately as a social phenomenon, when considering strategies for the development towards sustainability. This paper presents the concept of Responsible Corporate Governance (RCG), as a strategy to "govern" TNCs. RCG is suggested as a stakeholder based policy instrument, which aims at allocating responsibilities to societal actors aiming at corporate accountability. RCG recognises that the process of societal change is strongly based on what can be called as bottom up-processes. Learning processes take place through the interaction of the different societal members, which eventually leads to macro changes. Therefore, governing TNCs towards sustainability improvements is considered to be a collective process including all stakeholders. Firstly, the paper places the concept of RCG in the ongoing debate of political modernization based on the fact that society develops overtime and the political system must correspondingly modernize. In this context, political overload developed as a consequence of increased resource interdependencies is explained and as a resolution, network approach is discussed. Secondly, demands on the orientation of the TNCs in terms of accountability and innovative action are brought forward. Here, the paper also lists down corporate elements (stakeholder empowered corporate governance, management and performance evaluation systems, transparency enhancement and accountability verification), which need to be in place to attain an accountable orientation in the society. Following, using an analytical framework, the orientation and capabilities of each societal actor (environmental non-governmental organisations, financial institutions, intergovernmental organisations) to affect improvements in the corporate responsibility elements are investigated and recommendations for their effective orientation are listed.

Description: In jedem Unternehmen gibt es Potenziale, um die eigene wirtschaftliche Position zu verbessern und sich gegen zukünftige Krisen abzusichern. Technische, organisatorische oder soziale Innovationen sind der Schlüssel zur dauerhaften Sicherung ihrer Wettbewerbsposition. Diese Broschüre soll kleinen und mittelständischen Unternehmen helfen, Bereiche zu finden, in denen Innovationspotenziale vorhanden sind. Anhand erster Maßnahmen, so genannten Innovationsschritten, werden Ansatzpunkte entwickelt, wie mit möglichst geringem (Zeit- und Kosten-) Aufwand gezielt die eigene Wettbewerbsposition gestärkt werden kann. Sie wendet sich an Unternehmensleitung oder Umweltmanagementbeauftragte und gibt ihnen einen ersten Ein- bzw. Überblick und konkrete Vorschläge, wie sie die Zukunftsfähigkeit ihres Unternehmens verbessern können. Damit hat diese Broschüre konkrete Hilfestellungen für den Praktiker im Unternehmen im Fokus. Mögliche Ansatzpunkte, geeignete Wege sowie passende Instrumente werden für einzelne Bereiche aufgezeigt und erläutert.

Description: Diese Studie untersucht die Medien, die sanktionsbereiten Konsumenten Informationen über die Verantwortung von Unternehmen als Orientierungshilfe für den Einkauf anbieten. Im Brennpunkt stehen dabei sozial-ökologisch orientierte Einkaufsführer, die vergleichende Unternehmensbewertungen mit dem Ziel anbieten, Verbrauchern eine Informationsgrundlage für positive und negative Sanktionen zu geben, um einen positiven Profilierungswettbewerb in Gang zu setzen. Dabei gilt das besondere Interesse dem Übergang vom Printmedium zum Internetauftritt. Ziel der Untersuchung ist eine Analyse fördernder und hemmender Faktoren für den Erfolg, die für die Praxis nützlich sein soll.

Description: Infrastrukturen und Infrastrukturpolitik nehmen einen entscheidenden Einfluss auf die Nachhaltigkeit eines Landes. Betrachtet man die (Fehl-) Entwicklungen des letzten Jahrhunderts in den Industrieländern, so ist zu erkennen, dass die derzeitigen Energie-, Verkehrs- und Wasserinfrastrukturen selbst den Anforderungen einer ökonomischen Nachhaltigkeit nicht gewachsen sind. Ihre sozialen und ökologischen Folgen wurden zudem meist vernachlässigt und spielten bei Entscheidungsprozessen nur eine nachrangige Rolle. Große Herausforderungen liegen vor den Industrieländern, wenn sie nachhaltige Infrastrukturen schaffen wollen - und gar eine Leitbildfunktion für Schwellen- und Entwicklungsländer im 21. Jahrhundert einnehmen möchten. Denn durch die Intensivierung der weltweiten Austauschbeziehungen werden die nicht-nachhaltigen Infrastrukturkonzepte und -politiken der Industrieländer zunehmend auf Entwicklungsländer übertragen. Eine Umorientierung muss deshalb auch im Süden erfolgen. Dieses Wuppertal Paper bietet am Beispiel der drei wichtigen Sektoren Energie, Verkehr und Wasser Ansätze einer nachhaltigen Infrastrukturpolitik. Dazu gehören sowohl globale Lösungsstrategien als auch spezifische Instrumente für die Länder des Nordens oder des Südens. Im Rahmen von sektoralen Fallstudien werden die Schwellenländer Brasilien (Energie), China (Verkehr) und Indonesien (Wasser) betrachtet. Zudem werden Strategien und Erfolgsfaktoren für eine an Nachhaltigkeitszielen orientierte Transferpolitik skizziert, wobei auch auf die Bedeutung von Bildung und die Rolle internationaler Finanzinstitutionen (am Beispiel der Weltbank) eingegangen wird. Um die großen Herausforderungen einer globalen nachhaltigen Entwicklung zu bewältigen, schlägt dieses Papier vor, mehrere Strategien parallel zu verfolgen. Im Norden sind die gegenwärtigen ressourcenintensiven, nicht-nachhaltigen Infrastrukturen zu überdenken. Im Süden sollte der Pfad der "nachholenden Entwicklung" verlassen und im Sinne eines ökologischen "leapfrogging" der Sprung in post-fossile Infrastrukturen angestrebt werden, um nicht die Fehler des Nordens zu wiederholen. Länderspezifische Lösungen sollten dabei an die Stelle eines Imports nicht-angepasster Infrastrukturen treten. Der Transfer und Austausch von Ideen, Konzepten und Lösungen kann dabei einen wesentlichen Beitrag leisten, wobei eine unidirektionale Entwicklungszusammenarbeit von Nord nach Süd nicht ausreicht. Auch Süd-Süd oder Süd-Nord-Kooperationen eröffnen wichtige Chancen. Zudem ist der industrieländerzentrische, Technologie orientierte Ansatz einer einfachen Optimierung der supply-side zu verlassen zugunsten einer Handlungsstrategie, die ein nachhaltiges demand-side-management integriert.

Description: An increasing number of publications about theoretical approaches and new findings illustrate the relevance of the topic environmental risk assessment. The actual discussion about high oil prices is not incorporated under this headline; but it should be, as natural resource scarcity is a crucial economic factor. In practical experience, more and more banks, insurance companies as well as investors realize that there are certain areas with a high correlation between sustainable development and corporate success, corporate risk exposure and corporate performance. In this discussion one of the most obvious topics are risks related to climate change. According to the findings of surveys evaluated in this paper climate change starts to affect economic development and companies' performance in various ways. Over the next decade, economic losses due to climate change are estimated by US$ 150 billion per year. As result world's business leaders have described climate change as the biggest challenge of the 21st century. Hence, the incorporation of climate change as a risk factor is essential, but risks related to climate change feature a severe issue of complex structure and uncertainty; traditional risk assessment tools appear in the light of not being able to either reflect the multifaceted system nor provide sufficient outcomes. Environmental risk assessments in general so far have mainly emphasized - if at all - on actual and possible impacts of the release of materials or emissions (external effects). But an overall sustainable risk assessment has also to take into account the risks related to the inflow of materials. The main reason for neglecting the inflow risks from an environmental perspective can be seen in the fact that these risks seem to be less tangible and more uncertain. Nevertheless, in a world where economic development and the use of natural resources is not uncoupled yet, a steadily increasing economic power will result in a continually rising extraction of resources. As all resources are limited, the risk of scarcity will rise; and the example of water illustrates that it already exists. Indeed, scarcity is not tangible for all kind of resources from a present point of view. Hence, a specified analysis is needed considering different market and supply conditions. A comprehensive analysis of environmental risks needs to encompass risks affecting the output as well as the input side of a value chain. This paper enlarges the discussion on environmental risk assessments upon the input dimension using the example of carbon risks. Firstly, carbon risks are defined as risks related to climate change at the corporate level with a focus on the input as well as the output dimension. Secondly, an analysis of the current discussion on the topic of carbon risk evaluates the status quo of scientific work in this field. Thirdly, in terms of developing a practically oriented tool, the Value-at-Risk approach and it's application to measure input oriented carbon risks are scrutinized. The results discuss how future volatility and market prices can be utilized to describe the uncertainty resulting from markets acknowledging and pricing oil scarcity as a risk factor. Finally recommendations with a focus on strategic management decisions and financial performance analysis are given and further research opportunities are drawn. The conclusion is; once markets have acknowledged the depletion mid-point as a measure of oil scarcity, natural scarcity will result in a significant higher Value-at-Risk. The Value-at-Risk of one barrel of crude oil could then be as high as US$ 15.5 in the short term and even US$ 17.2 in the long term. The scope of this paper is neither intended to predict one likely development nor to demonstrate how this tool can actually work in terms of forecasting single companies' performance. But in order to point the way ahead, this paper provides scenarios for potential future developments and sets a frame for risk assessments due to oil scarcity.

Description: Der neoliberalen Globalisierung liegen Rationalitätsmuster zugrunde, die weder neu, noch liberal sind. Dies gilt für herrschaftliches Denken über Natur (als Ressource) ebenso wie für den sich verstärkenden Zugriff auf Naturgüter und die Ausblendung reproduktiver Elemente aus der Debatte über Umgangsweisen mit Natur. Mit Blick auf Landnutzung und Livelihood wird lokale Vielfalt durch Globalisierung zerstört. Der Absolutheitsanspruch eines weltweit entfesselten Marktes mit seinem grenzenlos freien Wettbewerb untergräbt das Recht auf- und die Möglichkeit zu je eigener, der Lokalität gemäßer Naturnutzung. Wenn immer mehr Menschen ihrer an die jeweiligen Lokalitäten gebundenen Produktionsmittel beraubt werden, können sich Gesellschaften nicht von innen heraus nachhaltig entwickeln.

Description: This paper examines the connection between globalisation, with its growth in world trade links, and certain ecological effects especially concerning "North-South" relations. Although world trade in the mid-nineties was significantly uncoupled from growth trends in the world economy, so that since then it has increased nearly three times faster than the global GDP, certain indicators of energy use and CO2 emissions have not developed proportionately to world trade; globalisation evidently does not lead to a situation where pressures on the environment are increasing to the same extent worldwide. This de-linking may, however, result in the kind of shifts that we examine here with reference to the material trade flows of the European Union. It will be shown that, in the course of globalisation, the countries of the EU have increasingly shifted environmental burdens on to the countries of the South, especially in the form of ecological rucksacks of imported raw materials, while at the same time reducing the pressure on their own domestic environment by extracting fewer material resources. Furthermore, goods whose production places intensive pressure on the environment (industrial emissions into the atmosphere and water, heavy metal emissions, etc.) have been increasingly imported from newly industrializing or developing countries. The greater covering of material requirements from foreign resources has served not so much the EU's internal consumption as its own production of export goods; this shows that the EU has an increasing share in the resource requirement of other economies. The paper concludes that it is absolutely necessary to consider the international dimension in any strategy for more productive use of resources in industrial countries. In the long term, the EU's resource use should also be reduced in absolute terms. This will also be necessary in order to reduce the pressure on the environment due to imports and exports.

Description: Die "Ökonomie der Aufmerksamkeit" hat zur Herausbildung spezifischer Märkte für Kommunikations-, Media- und Marketingdienstleistungen geführt. Ein dynamisch wachsender Markt ist der Markt für Live-Kommunikation, der in dieser Arbeit vertiefend untersucht wird. Hierbei werden drei Fragen diskutiert: 1. Was sind die treibenden Faktoren und Trends der Live-Kommunikation? 2. Nach welchen Maßstäben werden Events, insbesondere im Bereich der Unternehmenskommunikation, beauftragt? 3. Welche Chancen bestehen in diesem Markt, Events für Nachhaltigkeit als Marktsegment zu etablieren und zu stärken? Bei der Beantwortung dieser Fragen werden aktuelle Trendstudien ausgewertet, aber auch auf Untersuchungen und Fallstudien zurückgegriffen, die im Rahmen des Projektes "Eventkultur und Nachhaltigkeit" durchgeführt wurden. Die Autoren kommen zu dem Ergebnis, dass die Markt- und Trendstudien eine wichtige Orientierungsfunktion für die Eventwirtschaft haben. Aus der Perspektive eines kulturökonomischen Ansatzes wird kritisiert, dass diese Orientierungsfunktion auf Marken und Marketingtechniken beschränkt ist und der Einfluss der gesellschaftlichen Wertbildung auf die Marketingpraxis ausgeblendet bleibt. Nachhaltige Ziele und Inhalte werden mit den Mitteln des Event-Marketings erst vereinzelt vermittelt. Aus diesen ersten Aktivitäten kann aber ein neuer Kommunikationsmarkt entstehen, wenn seitens der Nachhaltigkeitsakteure eine Verständigung über Kriterien und Anforderungen an dieses Marketinginstrument erfolgt sowie der Symbolebene in der Nachhaltigkeitskommunikation eine stärkere Beachtung geschenkt wird. Informationsbündelung und symbolisches Management sind wichtige Ansatzpunkte, um in der Marketingpraxis von Unternehmen, öffentlichen Einrichtungen, Verbänden, NGOs und von Kommunikations- und Eventagenturen eine nachhaltige Eventkultur zu verankern.

Description: Closed-loop flow control was successfully demonstrated on the surface of stator vanes in NASA Glenn Research Center's Low-Speed Axial Compressor (LSAC) facility. This facility provides a flow field that accurately duplicates the aerodynamics of modern highly loaded compressors. Closed-loop active flow control uses sensors and actuators embedded within engine components to dynamically alter the internal flow path during off-nominal operation in order to optimize engine performance and maintain stable operation.

Description: The goal of the Autonomous Propulsion System Technology (APST) project is to reduce pilot workload under both normal and anomalous conditions. Ongoing work under APST develops and leverages technologies that provide autonomous engine monitoring, diagnosing, and controller adaptation functions, resulting in an integrated suite of algorithms that maintain the propulsion system's performance and safety throughout its life. Engine-to-engine performance variation occurs among new engines because of manufacturing tolerances and assembly practices. As an engine wears, the performance changes as operability limits are reached. In addition to these normal phenomena, other unanticipated events such as sensor failures, bird ingestion, or component faults may occur, affecting pilot workload as well as compromising safety. APST will adapt the controller as necessary to achieve optimal performance for a normal aging engine, and the safety net of APST algorithms will examine and interpret data from a variety of onboard sources to detect, isolate, and if possible, accommodate faults. Situations that cannot be accommodated within the faulted engine itself will be referred to a higher level vehicle management system. This system will have the authority to redistribute the faulted engine's functionality among other engines, or to replan the mission based on this new engine health information. Work is currently underway in the areas of adaptive control to compensate for engine degradation due to aging, data fusion for diagnostics and prognostics of specific sensor and component faults, and foreign object ingestion detection. In addition, a framework is being defined for integrating all the components of APST into a unified system. A multivariable, adaptive, multimode control algorithm has been developed that accommodates degradation-induced thrust disturbances during throttle transients. The baseline controller of the engine model currently being investigated has multiple control modes that are selected according to some performance or operational criteria. As the engine degrades, parameters shift from their nominal values. Thus, when a new control mode is swapped in, a variable that is being brought under control might have an excessive initial error. The new adaptive algorithm adjusts the controller gains on the basis of the level of degradation to minimize the disruptive influence of the large error on other variables and to recover the desired thrust response.

Description: The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (Valley Forge, PA) under contract to the Department of Energy (Germantown, MD). In support of this project, the NASA Glenn Research Center has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system to be used in space. The generator will be a high-efficiency electric power source for potential use on NASA space science missions. The generator will be able to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power-conversion technology. The power output of the generator will be greater than 100 W at the beginning of life, with the slow decline in power being largely due to decay of the plutonium heat source. Previously, Glenn's supporting technology efforts focused only on the most critical technical issues.

Description: The potential benefits of nonlinear engine control technology applied to a General Electric T700 helicopter engine were investigated. This technology is being developed by the U.S. Navy SPAWAR Systems Center for a variety of applications. When used as a means of active stability control, nonlinear engine control technology uses sensors and small amounts of injected air to allow compressors to operate with reduced stall margin, which can improve engine pressure ratio. The focus of this study was to determine the best achievable reduction in fuel consumption for the T700 turboshaft engine. A customer deck (computer code) was provided by General Electric to calculate the T700 engine performance, and the NASA Glenn Research Center used this code to perform the analysis. The results showed a 2- to 5-percent reduction in brake specific fuel consumption (BSFC) at the three Sikorsky H-60 helicopter operating points of cruise, loiter, and hover.

Description: Rapidly emerging fuel-cell-power technologies may be used to launch a new revolution of electric propulsion systems for light aircraft. Future small electric airplanes using fuel cell technologies hold the promise of high reliability, low maintenance, low noise, and - with the exception of water vapor - zero emissions. An analytical feasibility and performance assessment was conducted by NASA Glenn Research Center's Airbreathing Systems Analysis Office of a fuel-cell-powered, propeller-driven, small electric airplane based on a model of the MCR-01 two-place kitplane (Dyn'Aero, Darois, France). This assessment was conducted in parallel with an ongoing effort by the Advanced Technology Products Corporation and the Foundation for Advancing Science and Technology Education. Their project - partially funded by a NASA grant - is to design, build, and fly the first manned, continuously propelled, nongliding electric airplane. In our study, an analytical performance model of a proton exchange membrane (PEM) fuel cell propulsion system was developed and applied to a notional, two-place light airplane modeled after the MCR-01 kitplane. The PEM fuel cell stack was fed pure hydrogen fuel and humidified ambient air via a small automotive centrifugal supercharger. The fuel cell performance models were based on chemical reaction analyses calibrated with published data from the fledgling U.S. automotive fuel cell industry. Electric propeller motors, rated at two shaft power levels in separate assessments, were used to directly drive a two-bladed, variable-pitch propeller. Fuel sources considered were compressed hydrogen gas and cryogenic liquid hydrogen. Both of these fuel sources provided pure, contaminant-free hydrogen for the PEM cells.

Description: Two experiments were conducted, using sound quality engineering practices, to determine the subjective effectiveness of hypothetical active noise control systems in a range of propeller aircraft. The two tests differed by the type of judgments made by the subjects: pair comparisons in the first test and numerical category scaling in the second. Although the results of the two tests were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference.

Description: The primary objective of this research program is to develop vibration analysis tools, design tools, and design strategies to significantly improve the safety and robustness of turbine engine rotors. Bladed disks in turbine engines always feature small, random blade-to-blade differences, or mistuning. Mistuning can lead to a dramatic increase in blade forced-response amplitudes and stresses. Ultimately, this results in high-cycle fatigue, which is a major safety and cost concern. In this research program, the necessary steps will be taken to transform a state-of-the-art vibration analysis tool, the Turbo-Reduce forced-response prediction code, into an effective design tool by enhancing and extending the underlying modeling and analysis methods. Furthermore, novel techniques will be developed to assess the safety of a given design. In particular, a procedure will be established for using eigenfrequency curve veerings to identify "danger zones" in the operating conditions--ranges of rotational speeds and engine orders in which there is a great risk that the rotor blades will suffer high stresses. This work also will aid statistical studies of the forced response by reducing the necessary number of simulations. Finally, new strategies for improving the design of rotors will be pursued. Several methods will be investigated, including the use of intentional mistuning patterns to mitigate the harmful effects of random mistuning, and the modification of disk stiffness to avoid reaching critical values of interblade coupling in the desired operating range. Recent research progress is summarized in the following paragraphs. First, significant progress was made in the development of the component mode mistuning (CMM) and static mode compensation (SMC) methods for reduced-order modeling of mistuned bladed disks (see the following figure). The CMM method has been formalized and extended to allow a general treatment of mistuning. In addition, CMM allows individual mode mistuning, which accounts for the realistic effects of local variations in blade properties that lead to different mistuning values for different mode types (e.g., mistuning of the first torsion mode versus the second flexural mode). The accuracy and efficiency of the CMM method and the corresponding Turbo-Reduce code were validated for an example finite element model of a bladed disk.

Description: Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

Description: Modern engineering design practices are tending more toward the treatment of design parameters as random variables as opposed to fixed, or deterministic, values. The probabilistic design approach attempts to account for the uncertainty in design parameters by representing them as a distribution of values rather than as a single value. The motivations for this effort include preventing excessive overdesign as well as assessing and assuring reliability, both of which are important for aerospace applications. However, the determination of the probability distribution is a fundamental problem in reliability analysis. A random variable is often defined by the parameters of the theoretical distribution function that gives the best fit to experimental data. In many cases the distribution must be assumed from very limited information or data. Often the types of information that are available or reasonably estimated are the minimum, maximum, and most likely values of the design parameter. For these situations the beta distribution model is very convenient because the parameters that define the distribution can be easily determined from these three pieces of information. Widely used in the field of operations research, the beta model is very flexible and is also useful for estimating the mean and standard deviation of a random variable given only the aforementioned three values. However, an assumption is required to determine the four parameters of the beta distribution from only these three pieces of information (some of the more common distributions, like the normal, lognormal, gamma, and Weibull distributions, have two or three parameters). The conventional method assumes that the standard deviation is a certain fraction of the range. The beta parameters are then determined by solving a set of equations simultaneously. A new method developed in-house at the NASA Glenn Research Center assumes a value for one of the beta shape parameters based on an analogy with the normal distribution (ref.1). This new approach allows for a very simple and direct algebraic solution without restricting the standard deviation. The beta parameters obtained by the new method are comparable to the conventional method (and identical when the distribution is symmetrical). However, the proposed method generally produces a less peaked distribution with a slightly larger standard deviation (up to 7 percent) than the conventional method in cases where the distribution is asymmetric or skewed. The beta distribution model has now been implemented into the Fast Probability Integration (FPI) module used in the NESSUS computer code for probabilistic analyses of structures (ref. 2).

Description: Despite efforts in the search for alternative means of energy, combustion still remains the key source. Most propulsion systems primarily use combustion for their needed thrust. Associated with these propulsion systems are the high-velocity hot exhaust gases produced as the byproducts of combustion. These exhaust products often apply uneven high temperature and pressure over the surfaces of the appended structures exposed to them. If the applied pressure and temperature exceed the design criteria of the surfaces of these structures, they will not be able to protect the underlying structures, resulting in the failure of the vehicle mission. An understanding of the flow field associated with hot exhaust jets and the interactions of these jets with the structures in their path is critical not only from the design point of view but for the validation of the materials and manufacturing processes involved in constructing the materials from which the structures in the path of these jets are made. The hot exhaust gases often flow at supersonic speeds, and as a result, various incident and reflected shock features are present. These shock structures induce abrupt changes in the pressure and temperature distribution that need to be considered. In addition, the jet flow creates a gaseous plume that can easily be traced from large distances. To study the flow field associated with the supersonic gases induced by a rocket engine, its interaction with the surrounding surfaces, and its effects on the strength and durability of the materials exposed to it, NASA Glenn Research Center s Combustion Branch teamed with the Ceramics Branch to provide testing and analytical support. The experimental work included the full range of heat flux environments that the rocket engine can produce over a flat specimen. Chamber pressures were varied from 130 to 500 psia and oxidizer-to-fuel ratios (o/f) were varied from 1.3 to 7.5.

Description: Unsteady ejectors are currently under investigation for use in some pulse-detonation-engine-based propulsion systems. Experimental measurements made in the past, and recently at the NASA Glenn Research Center, have demonstrated that thrust augmentation can be enhanced considerably when the driver is unsteady. In ejector systems, thrust augmentation is defined as = T(sup Total)/T(sup j), where T(sup Total) is the total thrust of the combined ejector and driving jet and T(sup j) is the thrust due to the driving jet alone. There are three images in this figure, one for each of the named thrust sources. The images are color contours of measured instantaneous vorticity. Each image is an ensemble average of at least 150 phase-locked measurements. The flow is from right to left, and the shape and location of each driver is shown on the far right of each image. The emitted vortex is a clearly defined "doughnut" of highly vortical (spinning) flow. In these planar images, the vortex appears as two distorted circles, one above, and one below the axis of symmetry. Because they are spinning in the opposite direction, the two circles have vorticity of opposite sign and thus are different colors. There is also a rectangle shown in each image. Its width represents the ejector diameter that was found experimentally to yield the highest thrust augmentation. It is apparent that the optimal ejector diameter is that which just "captures" the vortex: that is, the diameter bounding the outermost edge of the vortex structure. The exact mechanism behind the enhanced performance is unclear; however, it is believed to be related to the powerful vortex emitted with each pulse of the unsteady driver. As such, particle imaging velocimetry (PIV) measurements were obtained for three unsteady drivers: a pulsejet, a resonance tube, and a speaker-driven jet. All the drivers were tested with ejectors, and all exhibited performance enhancement over similarly sized steady drivers. The characteristic starting vortices of each driver are shown in these images. The images are color contours of measured instantaneous vorticity. Each image is an ensemble average of at least 150 phase-locked measurements. The flow is from right to left. The shape and location of each driver is shown on the far right of each image. The rectangle shown in each image represents the ejector diameter that was found experimentally to yield the highest thrust augmentation. It is apparent that the optimal ejector diameter is that which just "captures" the vortex: that is, the diameter bounding the outermost edge of the vortex structure. Although not shown, it was observed that the emitted vortex spread as it traveled downstream. The spreading rate for the pulsejet is shown as the dashed lines in the top image. A tapered ejector was fabricated that matched this shape. When tested, the ejector demonstrated superior performance to all those previously tested at Glenn (which were essentially of straight, cylindrical form), achieving a remarkable thrust augmentation of 2. The measured thrust augmentation is shown as a function of ejector length. Also shown are the thrust augmentation values achieved with the straight, cylindrical ejectors of varying diameters. Here, thrust augmentation is plotted as a function of ejector length for several families of ejector diameters. It can be seen that large thrust augmentation values are indeed obtained and that they are sensitive to both ejector length and diameter, particularly the latter. Five curves are shown. Four correspond to straight ejector diameters of 2.2, 3.0, 4.0, and 6.0 in. The fifth curve corresponds to the tapered ejector contoured to bound the emitted vortex. For each curve, there are several data points corresponding to different lengths. The largest value of thrust augmentation is 2.0 for the tapered ejector and 1.81 for the straight ejectors. Regardless of their diameters, all the ejectors trend toward peak performance at a particular leng. That the cross-sectional dimensions of optimal ejectors scaled precisely with the vortex dimensions on three separate pulsed thrust sources demonstrates that the action of the vortex is responsible for the enhanced ejector performance. The result also suggests that, in the absence of a complete understanding of the entrainment and augmentation mechanisms, methods of characterizing starting vortices may be useful for correlating and predicting unsteady ejector performance.

Description: NASA's previous Advanced Subsonic Technology (AST) Noise Reduction Program delivered the initial technologies for meeting a 10-year goal of a 10-dB reduction in total aircraft system noise. Technology Readiness Levels achieved for the engine-noise-reduction technologies ranged from 4 (rig scale) to 6 (engine demonstration). The current Quiet Aircraft Technology (QAT) project is building on those AST accomplishments to achieve the additional noise reduction needed to meet the Aerospace Technology Enterprise's 10-year goal, again validated through a combination of laboratory rig and engine demonstration tests. In order to meet the Aerospace Technology Enterprise goal for future aircraft of a 50- reduction in the perceived noise level, reductions of 4 dB are needed in both fan and jet noise. The primary objectives of the Engine Noise Reduction Systems (ENRS) subproject are, therefore, to develop technologies to reduce both fan and jet noise by 4 dB, to demonstrate these technologies in engine tests, and to develop and experimentally validate Computational Aero Acoustics (CAA) computer codes that will improve our ability to predict engine noise.

Description: The Ultra-Efficient Engine Technology (UEET) Project is formulated according to the Office of Aerospace Technology's objectives as outlined in the NASA Strategic Plan. It is directly related to the "protect the environment" objective and will make progress toward the "increase mobility" and "support national security" objectives as well. UEET technologies will impact future civil and military aircraft and will benefit the development of future space transportation propulsion systems. UEET Project success will, therefore, depend on developing revolutionary, but affordable, technology solutions that are inherently safe and reliable and thus can be incorporated in future propulsion system designs. In fiscal year 2003, UEET became part of NASA's Vehicle Systems Program and continues to evolve its programmatic role. The Vehicle Systems Program aims to develop breakthrough technologies and methodologies, push the boundaries of flight through research on advanced vehicle concepts, respond quickly to industry and the Department of Defense on critical safety and other issues, and provide facilities and expert consultation for industry and other Government agencies during product development.

Description: Turbine engine studies have shown that reducing high pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin and increase range. Dr. Lattime presented the design and development status of a new Active Clearance Control Test rig aimed at demonstrating advanced ACC approaches and sensors. Mr. Melcher presented controls considerations for turbine active clearance control. Mr. Geisheimer of Radatech presented an overview of their microwave blade tip sensor technology. Microwave tip sensors show promise of operation in the extreme gas temperatures present in the HPT location. Mr. Justak presented an overview of non-contacting seal developments at Advanced Technologies Group. Dr. Braun presented investigations into a non-contacting finger seal under development by NASA GRC and University of Akron. Dr. Stango presented analytical assessments of the effects of flow-induced radial loads on brush seal behavior. Mr. Flaherty presented innovative seal and seal fabrication developments at FlowServ. Mr. Chappel presented abradable seal developments at Technetics. Dr. Daniels presented an overview of NASA GRC s acoustic seal developments. NASA is investigating the ability to harness high amplitude acoustic waves, possible through a new field of acoustics called Resonant Macrosonic Synthesis, to effect a non-contacting, low leakage seal. Dr. Daniels presented early results showing the ability to restrict flow via acoustic pressures. Dr. Athavale presented numerical results simulating the flow blocking capability of a pre-prototype acoustic seal.

Description: This presentation discusses active control of turbine tip clearance from a control systems perspective. It is a subset of charts that were presented at the 2003 meeting of the International Society of Air Breathing Engines which was held August 31 through September 5 in Cleveland, Ohio. The associated reference paper is cited at the end of the presentation. The presentation describes active tip clearance control research being conducted by NASA to improve turbine engine systems. The target application for this effort is commercial aircraft engines. However, it is believed that the technologies developed as part of this research will benefit a broad spectrum of current and future turbomachinery. The first part of the presentation discusses the concept of tip clearance, problems associated with it, and the benefits of controlling it. It lays out a framework for implementing tip clearance controls that enables the implementation to progress from purely analytical to hardware-in-the-loop to fully experimental. And it briefly discusses how the technologies developed will be married to the previously described ACC Test Rig for hardware-in-the-loop demonstrations. The final portion of the presentation, describes one of the key technologies in some detail by presenting equations and results for a functional dynamic model of the tip clearance phenomena. As shown, the model exhibits many of the clearance dynamics found in commercial gas turbine engines. However, initial attempts to validate the model identified limitations that are being addressed to make the model more realistic.

Description: This viewgraph presentation provides organizational plans and a schedule for the development of clean, quiet, and efficient propulsion technology for future aircraft.

Description: Room temperature testing of an 8.5 inch diameter foil seal was conducted in the High Speed, High Temperature Turbine Seal Test Rig at the NASA Glenn Research Center. The seal was operated at speeds up to 30,000 rpm and pressure differentials up to 75 psid. Seal leakage and power loss data will be presented and compared to brush seal performance. The failure of the seal and rotor coating at 30,000 rpm and 15 psid will be presented and future development needs discussed.

Description: NASA Glenn Research Center's Engineering Development Division has been working in support of innovative gas turbine engine systems under development by Glenn's Combustion Branch. These one-of-a-kind components require operation under extreme conditions. High-temperature ceramics were chosen for fabrication was because of the hostile operating environment. During the designing process, it became apparent that traditional machining techniques would not be adequate to produce the small, intricate features for the conceptual design, which was to be produced by stacking over a dozen thin layers with many small features that would then be aligned and bonded together into a one-piece unit. Instead of using traditional machining, we produced computer models in Pro/ENGINEER (Parametric Technology Corporation (PTC), Needham, MA) to the specifications of the research engineer. The computer models were exported in stereolithography standard (STL) format and used to produce full-size rapid prototype polymer models. These semi-opaque plastic models were used for visualization and design verification. The computer models also were exported in International Graphics Exchange Specification (IGES) format and sent to Glenn's Thermal/Fluids Design & Analysis Branch and Applied Structural Mechanics Branch for profiling heat transfer and mechanical strength analysis.

Description: A scaled blade-tip-drive test rig was designed at the NASA Glenn Research Center. The rig is a scaled version of a direct-current brushless motor that would be located in the shroud of a thrust fan. This geometry is very attractive since the allowable speed of the armature is approximately the speed of the blade tips (Mach 1 or 1100 ft/s). The magnetic pressure generated in the motor acts over a large area and, thus, produces a large force or torque. This large force multiplied by the large velocity results in a high-power-density motor.

Description: The high-cycle fatigue of composite stator vanes provided an accelerated life-state prior to insertion in a test stand engine. The accelerated testing was performed in the Structural Dynamics Laboratory at the NASA Glenn Research Center under the guidance of Structural Mechanics and Dynamics Branch personnel. Previous research on fixturing and test procedures developed at Glenn determined that engine vibratory conditions could be simulated for polymer matrix composite vanes by using the excitation of a combined slip table and electrodynamic shaker in Glenn's Structural Dynamics Laboratory. Bench-top testing gave researchers the confidence to test the coated vanes in a full-scale engine test.

Description: The NASA Glenn Research Center is developing advanced control surface seals and propulsion system seals for future space and launch vehicles. To evaluate new seal designs, the Glenn Seals Team recently inaugurated a new state-of-the-art high temperature seal test facility. The Hot Compression/Hot Scrub Rig can perform either high-temperature seal-compression tests or scrub tests at temperatures of up to 3000 F by using different combinations of test fixtures made of monolithic silicon carbide (Hexoloy alpha-SiC), as shown in the following figures. For lower temperature tests (up to 1500 F), Inconel X-750 test fixturing can be used.

Description: Superalloy lattice block panels, which are produced directly by investment casting, are composed of thin ligaments arranged in three-dimensional triangulated trusslike structures (see the preceding figure). Optionally, solid panel face sheets can be formed integrally during casting. In either form, lattice block panels can easily be produced with weights less than 25 percent of the mass of a solid panel. Inconel 718 (IN 718) and MarM-247 superalloy lattice block panels have been developed under NASA's Ultra-Efficient Engine Technology Project and Higher Operating Temperature Propulsion Components Project to take advantage of the superalloys' high strength and elevated temperature capability with the inherent light weight and high stiffness of the lattice architecture (ref. 1). These characteristics are important in the future development of turbine engine components. Casting quality and structural efficiency were evaluated experimentally using small beam specimens machined from the cast and heat treated 140- by 300- by 11-mm panels. The matrix of specimens included samples of each superalloy in both open-celled and single-face-sheet configurations, machined from longitudinal, transverse, and diagonal panel orientations. Thirty-five beam subelements were tested in Glenn's Life Prediction Branch's material test machine at room temperature and 650 C under both static (see the following photograph) and cyclic load conditions. Surprisingly, test results exceeded initial linear elastic analytical predictions. This was likely a result of the formation of plastic hinges and redundancies inherent in lattice block geometry, which was not considered in the finite element models. The value of a single face sheet was demonstrated by increased bending moment capacity, where the face sheet simultaneously increased the gross section modulus and braced the compression ligaments against early buckling as seen in open-cell specimens. Preexisting flaws in specimens were not a discriminator in flexural, shear, or stiffness measurements, again because of redundant load paths available in the lattice block structure. Early test results are available in references 2 and 3; more complete analyses are scheduled for publication in 2004.

Description: In recent years, there has been an increasing interest in developing rotating machinery shaft crack-detection methodologies and online techniques. Shaft crack problems present a significant safety and loss hazard in nearly every application of modern turbomachinery. In many cases, the rotors of modern machines are rapidly accelerated from rest to operating speed, to reduce the excessive vibrations at the critical speeds. The vibration monitoring during startup or shutdown has been receiving growing attention (ref. 1), especially for machines such as aircraft engines, which are subjected to frequent starts and stops, as well as high speeds and acceleration rates. It has been recognized that the presence of angular acceleration strongly affects the rotor's maximum response to unbalance and the speed at which it occurs. Unfortunately, conventional nondestructive evaluation (NDE) methods have unacceptable limits in terms of their application for online crack detection. Some of these techniques are time consuming and inconvenient for turbomachinery service testing. Almost all of these techniques require that the vicinity of the damage be known in advance, and they can provide only local information, with no indication of the structural strength at a component or system level. In addition, the effectiveness of these experimental techniques is affected by the high measurement noise levels existing in complex turbomachine structures. Therefore, the use of vibration monitoring along with vibration analysis has been receiving increasing attention.

Description: There is a growing interest in the use of fuel cells as a power source for all-electric aircraft propulsion as a means to substantially reduce or eliminate environmentally harmful emissions. Among the technologies under consideration for these concepts are advanced proton exchange membrane (PEM) and solid oxide fuel cells (SOFCs), alternative fuels and fuel processing, and fuel storage. A multidisciplinary effort is underway at the NASA Glenn Research Center to develop and evaluate concepts for revolutionary, nontraditional fuel cell power and propulsion systems for aircraft applications. As part of this effort, system studies are being conducted to identify concepts with high payoff potential and associated technology areas for further development. To support this effort, a suite of component models was developed to estimate the mass, volume, and performance for a given system architecture. These models include a hydrogen-air PEM fuel cell; an SOFC; balance-of-plant components (compressor, humidifier, separator, and heat exchangers); compressed gas, cryogenic, and liquid fuel storage tanks; and gas turbine/generator models for hybrid system applications. First-order feasibility studies were completed for an all-electric personal air vehicle utilizing a fuel-cell-powered propulsion system. A representative aircraft with an internal combustion engine was chosen as a baseline to provide key parameters to the study, including engine power and subsystem mass, fuel storage volume and mass, and aircraft range. The engine, fuel tank, and associated ancillaries were then replaced with a fuel cell subsystem. Various configurations were considered including a PEM fuel cell with liquid hydrogen storage, a direct methanol PEM fuel cell, and a direct internal reforming SOFC/turbine hybrid system using liquid methane fuel. Each configuration was compared with the baseline case on a mass and range basis.

Description: Today's form of jet engine power comes from what is called a gas turbine engine. This engine is on average 14% efficient and emits great quantities of green house gas carbon dioxide and air pollutants, Le. nitrogen oxides and sulfur oxides. The alternate method being researched involves a reformer and a solid oxide fuel cell (SOFC). Reformers are becoming a popular area of research within the industry scale. NASA Glenn Research Center's approach is based on modifying the large aspects of industry reforming processes into a smaller jet fuel reformer. This process must not only be scaled down in size, but also decrease in weight and increase in efficiency. In comparison to today's method, the Jet A fuel reformer will be more efficient as well as reduce the amount of air pollutants discharged. The intent is to develop a 10kW process that can be used to satisfy the needs of commercial jet engines. Presently, commercial jets use Jet-A fuel, which is a kerosene based hydrocarbon fuel. Hydrocarbon fuels cannot be directly fed into a SOFC for the reason that the high temperature causes it to decompose into solid carbon and Hz. A reforming process converts fuel into hydrogen and supplies it to a fuel cell for power, as well as eliminating sulfur compounds. The SOFC produces electricity by converting H2 and CO2. The reformer contains a catalyst which is used to speed up the reaction rate and overall conversion. An outside company will perform a catalyst screening with our baseline Jet-A fuel to determine the most durable catalyst for this application. Our project team is focusing on the overall research of the reforming process. Eventually we will do a component evaluation on the different reformer designs and catalysts. The current status of the project is the completion of buildup in the test rig and check outs on all equipment and electronic signals to our data system. The objective is to test various reformer designs and catalysts in our test rig to determine the most efficient configuration to incorporate into the specific compact jet he1 reformer test rig. Additional information is included in the original extended abstract.

Description: The Ultra-Efficient Engine Technology (UEET) Office at NASA Glenn Research Center is a part of the Aeronautics Directorate. Its vision is to develop and hand off revolutionary turbine engine propulsion technologies that will enable future generation vehicles over a wide range of flight speeds. There are seven different technology area projects of UEET. During my tenure at NASA Glenn Research Center, my assignment was to assist three different areas of UEET, simultaneously. I worked with Kathy Zona in Education Outreach, Lynn Boukalik in Knowledge Management, and Denise Busch with Financial Management. All of my tasks were related to the business side of UEET. As an intern with Education Outreach I created a word search to partner with an exhibit of a Turbine Engine developed out of the UEET office. This exhibit is a portable model that is presented to students of varying ages. The word search complies with National Standards for Education which are part of every science, engineering, and technology teachers curriculum. I also updated a Conference Planning/Workshop Excel Spreadsheet for the UEET Office. I collected and inputted facility overviews from various venues, both on and off site to determine where to hold upcoming conferences. I then documented which facilities were compliant with the Federal Emergency Management Agency's (FEMA) Hotel and Motel Fire Safety Act of 1990. The second area in which I worked was Knowledge Management. a large knowledge management system online which has extensive documentation that continually needs reviewing, updating, and archiving. Knowledge management is the ability to bring individual or team knowledge to an organizational level so that the information can be stored, shared, reviewed, archived. Livelink and a secure server are the Knowledge Management systems that UEET utilizes, Through these systems, I was able to obtain the documents needed for archiving. My assignment was to obtain intellectual property including reports, presentations, or any other documents related to the project. My next task was to document the author, date of creation, and all other properties of each document. To archive these documents I worked extensively with Microsoft Excel. different financial systems of accounting such as the SAP business accounting system. I also learned the best ways to present financial data and shadowed my mentor as she presented financial data to both UEET's project management and the Resources Analysis and Management Office (RAMO). I analyzed the June 2004 financial data of UEET and used Microsoft Excel to input the results of the data. This process made it easier to present the full cost of the project in the month of June. In addition I assisted in the End of the Year 2003 Reconciliation of Purchases of UEET.

Description: This paper addresses the requirements of a control system for active turbine tip clearance control in a generic commercial turbofan engine through design and analysis. The control objective is to articulate the shroud in the high pressure turbine section in order to maintain a certain clearance set point given several possible engine transient events. The system must also exhibit reasonable robustness to modeling uncertainties and reasonable noise rejection properties. Two actuators were chosen to fulfill such a requirement, both of which possess different levels of technological readiness: electrohydraulic servovalves and piezoelectric stacks. Identification of design constraints, desired actuator parameters, and actuator limitations are addressed in depth; all of which are intimately tied with the hardware and controller design process. Analytical demonstrations of the performance and robustness characteristics of the two axisymmetric LQG clearance control systems are presented. Takeoff simulation results show that both actuators are capable of maintaining the clearance within acceptable bounds and demonstrate robustness to parameter uncertainty. The present model-based control strategy was employed to demonstrate the tradeoff between performance, control effort, and robustness and to implement optimal state estimation in a noisy engine environment with intent to eliminate ad hoc methods for designing reliable control systems.

Description: A Data Fusion System designed to provide a reliable assessment of the occurrence of Foreign Object Damage (FOD) in a turbofan engine is presented. The FOD-event feature level fusion scheme combines knowledge of shifts in engine gas path performance obtained using a Kalman filter, with bearing accelerometer signal features extracted via wavelet analysis, to positively identify a FOD event. A fuzzy inference system provides basic probability assignments (bpa) based on features extracted from the gas path analysis and bearing accelerometers to a fusion algorithm based on the Dempster-Shafer-Yager Theory of Evidence. Details are provided on the wavelet transforms used to extract the foreign object strike features from the noisy data and on the Kalman filter-based gas path analysis. The system is demonstrated using a turbofan engine combined-effects model (CEM), providing both gas path and rotor dynamic structural response, and is suitable for rapid-prototyping of control and diagnostic systems. The fusion of the disparate data can provide significantly more reliable detection of a FOD event than the use of either method alone. The use of fuzzy inference techniques combined with Dempster-Shafer-Yager Theory of Evidence provides a theoretical justification for drawing conclusions based on imprecise or incomplete data.

Description: This paper addresses two aspects of duct propagation and radiation which can contribute to more efficient fan noise predictions. First, we assess the effectiveness of Rayleigh's formula as a ducted fan noise prediction tool. This classical result which predicts the sound produced by a piston in a flanged duct is expanded to include the uniform axial inflow case. Radiation patterns using Rayleigh's formula with single radial mode input are compared to those obtained from the more precise ducted fan noise prediction code TBIEM3D. Agreement between the two methods is excellent in the peak noise regions both forward and aft. Next, we use TBIEM3D to calculate generalized radiation impedances and power transmission coefficients. These quantities are computed for a wide range of operating parameters. Results were obtained for higher Mach numbers, frequencies, and circumferential mode orders than have been previously published. Viewed as functions of frequency, calculated trends in lower order inlet impedances and power transmission coefficients are in agreement with known results. The relationships are more oscillatory for higher order modes and higher Mach numbers.

Description: Active, closed-loop control of combustor pattern factor is a cooperative effort between Honeywell (formerly AlliedSignal) Engines and Systems and the NASA Glenn Research Center to reduce emissions and turbine-stator vane temperature variations, thereby enhancing engine performance and life, and reducing direct operating costs. Total fuel flow supplied to the engine is established by the speed/power control, but the distribution to individual atomizers will be controlled by the Active Combustor Pattern Factor Control (ACPFC). This system consist of three major components: multiple, thin-film sensors located on the turbine-stator vanes; fuel-flow modulators for individual atomizers; and control logic and algorithms within the electronic control.