ALBERT

Description: Die Produktion von Kunststoffen ist eine Geschichte extremen Wachstums: waren es global 1950 noch 1,7 Millionen, sind es 2012 weltweit 288 Millionen Tonnen (Mt). 57 Mt davon werden in der EU erzeugt mit einem gleichzeitigen Abfallvolumen von 25 Mt. Einher gehen hohe Verbräuche fossiler Rohstoffe mit entsprechenden Umweltbelastungen und massiven Schäden, die durch Plastikmüll verursacht werden. Das Wuppertal Institut hat im Auftrag des Naturschutzbunds Deutschland (NABU) untersucht, wie sich dieser Wachstumstrend in Deutschland ohne Gegensteuerung fortsetzen wird und mit welchen Strategien die Plastikflut eingedämmt werden kann. Die Autoren der Studie errechneten einen Steigerung um 28 Prozent bis zum Jahr 2030, insbesondere in den Bereichen Verpackungen und Bau. Für die künftig wichtigsten Anwendungsbereiche wurden in der Studie jeweils drei konkrete Ansätze zur Verringerung des Kunststoffeinsatzes aus den Bereichen Industrie, Handel und Haushalte ausgewählt. Diese neun Optionen wurden an Fallbeispielen auf ihre Vor- und Nachteile und die grundsätzliche technische, rechtliche und ökonomische Machbarkeit hin diskutiert. Umsetzungsansätze liefert die Studie für den politischen Raum, für Unternehmen und den privaten Konsum.

Description: Unternehmen sind heutzutage mit einer Vielzahl von Herausforderungen und Veränderungen konfrontiert, die zugleich Chance und Risiko für ihre wirtschaftliche Weiterentwicklung darstellen. Dazu gehören nicht nur grundlegende Trends wie Klimawandel, Ressourcenknappheit oder Urbanisierung, sondern auch der Wandel von Technologien, Geschäftsmodellen, gesetzlichen Rahmenbedingungen oder der gesellschaftlichen Akzeptanz. All dies hat globale und nationale Veränderungen in Märkten zur Folge und stellt die darin operierenden Unternehmen vor konkrete Herausforderungen. Die Auseinandersetzung mit der Zukunft gewinnt somit immer mehr an Bedeutung und stellt einen wichtigen Faktor für den langfristigen und nachhaltigen Erfolg eines Unternehmens dar. Die Strategische Frühaufklärung unterstützt Unternehmen dabei, Herausforderungen und Veränderungen rechtzeitig zu identifizieren und darauf zu reagieren. Stefan Reicherz erstellt eine flexible Blaupause hierfür: Individuell an ein Unternehmen angepasst, liefert sie diesem die notwendigen Informationen und Hilfsmittel, um erfolgreiche Strategische Frühaufklärung durchzuführen - und damit aus Risiken Chancen werden zu lassen.

Description: Ziel dieser Studie ist es, einen aktuellen Überblick über den Stand der Recyclingwirtschaft in Deutschland zu geben. Der Fokus liegt dabei vor allem auf den Marktprozessen, die bereits heute ökonomische Anreize zur Schließung von Stoffkreisläufen geben, bzw. auf spezifischen Hemmnissen, die genau solchen Entwicklungen im Wege stehen. Aufbauend auf der Analyse spezifischer Hemmnisse für einzelne Abfallfraktionen (rechtliche und institutionelle Hemmnisse, Marktmacht, Informationsdefizite etc.) leitet die Studie verschiedene Instrumente und handlungsorientierte Ansätze ab, die zu einer Verbesserung der Kreislaufführung beitragen könnten; dabei kann Deutschland auch von bestehenden Best-Practice-Ansätzen im Ausland profitieren. Dazu gehören unter anderem der verstärkte Einsatz ökonomischer Instrumente, Maßnahmen zur verstärkten Integration von Abfallwirtschaft und Produktionssektor, Urban Mining Konzepte, internationale Vereinbarungen zum Rohstoffrecycling sowie Green Tech Funds.

Description: Nach einer langen Phase der Stabilität ist die Stromwirtschaft in den vergangenen 15 Jahren stark in Bewegung geraten. Zunächst stand der Wechsel von staatlich überwachten und regulierten Gebietsmonopolen hin zu liberalisierten Erzeuger- und Verbrauchermärkten an. Im Moment befinden wir uns in einem ähnlichen Umbruch, weg von konventioneller hin zu erneuerbarer Energieerzeugung. Im vorliegenden Beitrag soll der Leitfrage nachgegangen werden, ob die Paradigmen der einzelnen Phasen miteinander vereinbar sind, welche noch immer ihre Daseinsberechtigung haben und welche modifiziert werden sollten.

Description: Effizienz - ist es das Hecheln nach mehr Leistung in derselben Zeit? Und Energieeffizienz ein Verbrauchsvergleichsstress? Nicht die Spur, meinen Kurt Berlo und Oliver Wagner, Experten vom Wuppertal Institut. Sie haben die Energieeffizienzstrategien der Ruhrgebietsstadtwerke untersucht.

Description: Nach einer langen Phase der Stabilität ist die Stromwirtschaft in den vergangenen 15 Jahren stark in Bewegung geraten. Mit der Liberalisierung stand zunächst der Wechsel von Gebietsmonopolen hin zu wettbewerblich organisierten Erzeuger- und Verbrauchermärkten an. Derzeit findet ein ganz ähnlicher Umbruch statt, der vom Übergang von konventioneller hin zu erneuerbarer Stromerzeugung gekennzeichnet ist. Aber sind die Paradigmen der einzelnen Phasen miteinander vereinbar und hat jede für sich noch immer ihre Daseinsberechtigung, oder ist hier eine Modifizierung notwendig? Das Strommarktdesign der Zukunft kann nicht auf einem leeren Blatt entworfen, sondern es müssen bestehende Strukturen berücksichtigt werden. Gleichzeitig ist die Frage zu beantworten, ob die Wahl zwischen regulatorischen oder marktbasierten Ansätzen sich auch anhand der mit ihnen möglichen Präzision der Steuerung unterscheidet.

Description: Digital platforms may yield a host of advantages in putting circular economy into effect. This paper analyses the related chances and discusses requirements of digital platforms for the realization of a circular economy. It specifically points to potential solutions offered by digital platforms for existing barriers. From there it identifies issues that need specific attendance to create economically and ecologically functional platforms. Three economically relevant perspectives are discussed for this: a management perspective, a legislative perspective and a social/systems perspective.

Description: Ex-ante policy evaluation requires a detailed understanding of how the subjects addressed by the policy react to its implementation. In the context of energy efficiency, policy measures typically aim at influencing investment decisions towards more efficient options. As has been discussed widely in the context of the "energy efficiency gap", investments in energy efficiency improvements are frequently not conducted even though they seem cost-effective from a simple cost-benefit perspective, where transaction costs have been identified as one important barrier. While transaction costs have been discussed widely from a conceptional perspective, empirical studies quantifying transaction costs and measures to reduce them are rare. This paper presents approaches, results and insights from a recently completed research project funded by the German Federal Energy Efficiency Center (BfEE), addressing transaction costs in various energy efficiency measures and the role of energy efficiency services to overcome the barrier. We analyse a set of 11 energy efficiency investments covering private households, public institutions and the industry sector. We gather data on direct investment costs and energy cost savings and provide a detailed analysis of the various barriers and transaction costs associated with the implementation. We then analyse the costs of existing energy efficiency services using data provided by the BfEE. We compare the different cost elements and analyze the potential of energy efficiency services to reduce transaction costs. We find that the role of transaction costs differs substantially between households, public institutions and companies and that the impact of energy efficiency services on transaction costs needs to be evaluated using different methodological approaches. We conclude that while data availability on disaggregated transaction costs is a major challenge, energy services can reduce transaction costs considerably.

Description: Because prevention is closely linked to complex consumption patterns, even cultural changes, such as increasing environmental awareness, changes in the average size of households or changes in the industrial structure of an economy, are relevant factors for the interpretation of changes in the generation of waste - it is more or less impossible to isolate the effect of specific waste prevention measures in this complex system. This must be considered, in particular, in international comparisons of policies and their potential transferability. The guidelines of the European Commission on waste prevention also point to the particular problem of data availability in the area of prevention: as waste statistics focus mainly on the treatment and fate of wastes, they are often of limited value for prevention of waste because they don't give sufficient information about their origins or reasons for their generation. Against this background, this report has the following objectives: Chapter 2 discusses strengths and weaknesses of typical waste-based prevention indicators; Chapter 3 analyses possible indicators that consider an upstream perspective and take into account the ecological rucksacks of products and components that have become waste; Chapter 4 focuses on specific product groups that could be targeted by waste prevention indicators. In general, the report describes the complexity of measuring waste prevention and outlines pros and cons of possible approaches. The final chapter aims to draw rather pragmatic conclusions on possibly most preferable options for future policy-making.

Description: Dieses Wuppertal Paper befasst sich mit folgenden Leitfragen: Wie wichtig sind Stadtwerke für die Energiewende? Was sind dabei die besonderen Beiträge von Stadtwerken? Hier ist insbesondere zu berücksichtigen, dass kommunal betriebene Kraft-Wärme-Kopplungs-Anlagen (KWK-Anlagen) ein wichtiger Komplementär zum Ausbau der erneuerbaren Energien darstellen und dass kommunale KWK-Anlagen inzwischen einen nennenswerten Beitrag zur Sicherstellung der Residuallast liefern. Zudem geht es um die Leitfrage, welche Rahmenbedingungen die Rolle von Stadtwerken als zentrale Akteure der Energiewende und insbesondere als Betreiber von KWK-Anlagen erschweren.

Description: Seit 2005 ist ein Großteil der deutschen Strom- und Gaskonzessionsverträge ausgelaufen und eröffnete vielen Kommunen die Chance, die Energieversorgung wieder in die eigenen Hände zu nehmen. Gleichzeitig übernimmt die kommunale Ebene in einem zunehmend dezentral strukturierten Energieversorgungssystem eine immer wichtigere Rolle, da die Umsetzung der energiepolitischen Ziele der Bundesregierung vor allem vor Ort, in den Kommunen stattfindet. Ziel dieser Arbeit war es daher, zu ermitteln wie viele Kommunen im Zeitraum von 2005 bis 2016 durch die Gründung neuer Unternehmen im Bereich der Energieversorgung tätig geworden sind und welche Rolle die kommunalen Energieversorgungsunternehmen im Rahmen der Energiewende einnehmen können. Auf Grundlage der bereits 2013 vom Wuppertal Institut durchgeführten Sondierungsstudie, die zahlreiche Neugründungen bis 2012 erfasste, konnten in dieser Arbeit insgesamt 139 kommunale Energieversorgungsunternehmen ermittelt werden, deren Gründung zwischen 2005 und 2016 stattfand. Dieses Ergebnis belegt für diesen Zeitraum einen ausgeprägten Trend zur Rekommunalisierung im Bereich der Energieversorgung. In einer umfangreichen Literaturanalyse sowie acht Experteninterviews mit kommunalen Ansprechpartnern und Geschäftsführern junger Stadtwerke, konnte darüber hinaus belegt werden, dass die kommunalen Energieversorger aufgrund ihrer Fachexpertise und ihrer ausgeprägten Vernetzung mit den Bürgern, örtlichen und regionalen Akteuren und der Kommune, wichtige Instrumente zur Umsetzung kommunaler Klimaschutzziele darstellen. Sie sind nicht nur in der Lage, sich im energiewirtschaftlichen Wettbewerb zu beweisen und zu positionieren, sondern können aufgrund ihrer lokalen Verankerung auch Potenziale erschließen, die von privaten Versorgern weitgehend ungenutzt bleiben. Diese umfassen beispielsweise Potenziale zur Energieerzeugung und -einsparung auf Kundenseite, aber auch die Möglichkeiten regenerativer Wärmeversorgung durch Nah- oder Fernwärme und eine stärkere Beteiligung der Bürger. Neben den zusätzlichen Wertschöpfungseffekten, von denen die Kommunen profitieren, ermöglichen die kommunalen Energieversorgungsunternehmen somit auch die aktive Mitgestaltung der Energiewende vor Ort, unter Einbeziehung der lokalen Akteure und Bürger.

Description: Stadtwerke sind im Ruhrgebiet strukturprägend und haben eine lange Tradition. Sie sind fester Bestandteil der Akteurskonstellation im Energiebereich der Emscher-Lippe-Zone. Schon heute zeichnen sich die Stadtwerke des Ruhrgebiets vielfach dadurch aus, dass sie die mit der Energiewende verbundenen Chancen nutzen. Ihre technische und gesellschaftliche Struktur entspricht weitgehend den mit der Energiewende verbundenen Transformationsprozessen hin zu einer stärkeren Dezentralität der Erzeugung und der Demokratisierung der Energieversorgung. Die meisten Stadtwerke des Ruhrgebiets sind auf mehreren Wertschöpfungsstufen im Energiebereich tätig. In der Stromerzeugung haben sie einen Schwerpunkt im Bereich der Kraft-Wärme-Kopplung und bei erneuerbaren Energien. Zudem sind sie vielerorts Partner und teilweise sogar Mitinitiator bürgerschaftlichen Engagements zum Ausbau erneuerbarer Energien. Als Verteilnetzbetreiber für Strom, Gas und Wärme sorgen sie vielerorts für die Integration und Verteilung erneuerbarer Energien. Die Energiewende findet weitgehend in den örtlichen Verteilnetzen statt und bedeutet für die Stadtwerke des Ruhrgebiets eine Zunahme an komplexen Koordinierungsfunktionen und teilweise auch die Herausbildung völlig neuer Aufgaben.

Description: Die Energiewende gilt als eine der zentralen gesellschaftlichen Projekte unserer Zeit. Ihre Bedeutung beschränkt sich nicht nur auf ihren bekannten Beitrag zum globalen Klimaschutz und auf die Reduzierung der Gefahren durch den Gebrauch von Atomenergie. Sie soll auch dazu dienen, die Energieimportabhängigkeit Deutschlands, mögliche Auswirkungen von Energiepreisschocks und die Wahrscheinlichkeit der Einbeziehung in zukünftige Ressourcenkriege zu reduzieren. Neben diesen Schutzfunktionen kann sie aber auch neue Geschäftsfelder und Arbeitsplätze schaffen und Innovationen in den Bereichen Effizienz und erneuerbare Energien voranbringen und damit einen Beitrag zu einer zukunftsorientierten, ökologischeren wirtschaftlichen Entwicklung beitragen. Bereits 2010 hat die Bundesregierung Ziele in Bezug auf den Ausbau erneuerbarer Energien, die Steigerung der Energieeffizienz sowie die Reduktion des CO2-Ausstoßes formuliert. Während die Ziele hinsichtlich des Ausbaus erneuerbarer Energien im Stromsektor und am Wärmeverbrauch voraussichtlich erreicht werden, sind im Bereich der Energieeffizienzsteigerung weitere Anstrengungen notwendig. Zwar gibt es zahlreiche Energiedienstleistungsangebote und Förderprogramme, mit denen die Energieeffizienz gesteigert werden sollen, allerdings haben diese - insbesondere bei kleinen und mittleren Unternehmen (KMU) - bisher nicht zu den gewünschten Ergebnissen geführt. Daher ist es Ziel der Arbeit, Ansätze für ein Konzept zur Realisierung von Energieeffizienzpotentialen in KMU zu entwickeln. Der Untersuchungsraum der Arbeit liegt im östlichen Ruhrgebiet in der Region Unna/Kamen/Bergkamen/Bönen/Holzwickede und ist auf das Projekt "SWOT-Analyse zur Energiewende Unna/Kamen/Bergkamen/Bönen/Holzwickede“ des Wuppertal Instituts zurückzuführen, in dessen Rahmen diese Arbeit entstand. Im Zuge der Analyse wurden zentrale interne und externe Einflussfaktoren auf die Entscheidung regionaler KMU zur Durchführung von Energieeffizienzmaßnahmen analysiert sowie Praxisbeispiele zur Realisierung von Energieeffizienzpotentialen ausgewertet. Abschließend wurden die Analyseergebnisse zu ersten Ideen für ein Konzept zur Realisierung von Energieeffizienzpotentialen in KMU ausgearbeitet und als Handlungsempfehlungen formuliert.

Description: Stadtwerke spielen für die Energiewende eine zentrale Rolle. Zum einen stellen sie in Deutschland weit über die Hälfte der Versorgung an Strom, Gas und Wärme sicher, zum anderen haben Stadtwerke aufgrund ihrer kommunalen Verankerung eine besondere Position im Spannungsgefüge von Politik, Wirtschaft und Privathaushalten. Wenn es aber um die Frage geht, was den Erfolg von neugegründeten Stadtwerken ausmacht, besteht in der Literatur in gewissem Maße eine Forschungslücke. Die vorliegende Studie, die vom Wuppertal Institut und der BLUBERRIES GmbH gemeinsam erstellt wurde, behandelt ausgewählte Handlungsfelder, bei denen ein Einfluss auf den Unternehmenserfolg von neugegründeten Stadtwerken zu vermuten ist. Dabei werden als Rahmen die Ziele der Rekommunalisierung herangezogen und konkret vier Handlungsfelder in den Vordergrund gerückt. Der Fokus der Studie liegt auf Fragestellungen nach dem wirtschaftlichen Erfolg neugegründeter Stadtwerke sowie deren Zielerreichung. Dabei wird auf den klassischen Ansatz der Erfolgsfaktorenforschung zurückgegriffen. Ziel dieser Studie ist die Formulierung erster Aussagen darüber, wie einerseits die unterstellten Handlungsfelder in ihrer Ausgestaltung, andererseits die Erfolgsmaße durch neugegründete Stadtwerke beurteilt werden. Aufgrund der im Rahmen dieser Untersuchung vorgenommenen Online-Befragung lassen sich für die in den Focus genommenen vier Handlungsfelder (Kooperationen, Digitalisierung, Resilienz und Soziale Verantwortung) die wichtigsten Ergebnisse wie folgt zusammenfassen: Kooperationen und verschiedene Formen der Zusammenarbeit in der Gründungsphase spielen für den Erfolg neu gegründeter Stadtwerke eine sehr große Rolle. Neu gegründete Stadtwerke legen meist großen Wert auf nachhaltige Geschäftsbeziehungen zu örtlichen Unternehmen, was einen wesentlichen Beitrag zum Public Value darstellt. Insbesondere gut ausgearbeitete Geschäftsstrategien in den Bereichen Erneuerbare Energien, Verteilnetzbetrieb, Vertrieb und Diversifikation unterstützen die Umsetzung der Unternehmensziele in Bezug auf Resilienz und Nachhaltigkeit. Die eher durchschnittliche Bewertung der Resilienz-Relevanz für den Ausbau eines Smart Grids im Verteilnetzbereich ist ein Indiz dafür, dass der Ordnungsrahmen so geändert werden müsste, dass Investitionen in diesem Bereich attraktiver werden. Aufgrund des explorativen Charakters der vorgelegten Studie, der keine repräsentativen Aussagen über die Erfolgsfaktoren von neugegründeten Stadtwerken zulässt, werden folgende vier Hypothesen abgeleitet: 1. Der Einsatz von horizontal-kooperativen Ansätzen in der Gründungsphase als ein spezifisches Wesensmerkmal der deutschen Stadtwerkelandschaft hat positive Auswirkungen auf die Verbesserung des wirtschaftlichen Erfolgs und der Rentabilität. 2. Der Fokus auf Resilienz, Nachhaltigkeit und Klimaschutz als zentrale Werte des Stadtwerks und als integrale Bestandteile des Unternehmensleitbildes unterstützt die Erreichung der strategischen Ziele des neugegründeten Stadtwerks. 3. Das Anbieten von Smart Metern zur Erhöhung der Kundentransparenz, zur Verbesserung des Kundennutzens und zur Optimierung des Verteilnetzmanagements kann als Erfolgsfaktor eingestuft werden und unterstützt seitens der Stadtwerke eine positive Unternehmensentwicklung nicht nur in der Startphase. 4. Die explizite Wahrnehmung von sozialer Verantwortung wirkt sich positiv auf den Unternehmenserfolg aus. Es müsste nun anschließend auf der Basis einer größeren Grundgesamtheit geprüft werden, ob und inwieweit die beschriebenen Tendenzen (die sich aus der Online-Befragung ergeben) und die explorativen Hypothesen im Rahmen eines konfirmatorischen Untersuchungsansatzes wissenschaftlich verifiziert werden können.

Description: Seit Mitte der 2000er Jahre ist in Deutschland ein Großteil der Konzessionsverträge für örtliche Strom-Verteilnetze ausgelaufen. Dies eröffnete den Kommunen vielerorts die Möglichkeit ihre bis dahin in privatem Besitz befindlichen Strom-Verteilnetze zu rekommunalisieren. Vor dem Hintergrund der Energiewende und dem damit einhergehenden Umbau der deutschen Energielandschaft hin zu dezentralen Versorgungsstrukturen eröffnete sich kommunalen Verantwortlichen so die Möglichkeit die Umsetzung energiepolitischer Ziele der Bundesregierung auf kommunaler Ebene aktiv mitzugestalten. Eine im Jahr 2013 durch das Wuppertal Institut durchgeführte Sondierungsstudie erfasste für den Zeitraum 2005 bis 2016 zahlreiche Stadtwerke-Neugründungen, welche einen Trend zur Rekommunalisierung im Bereich der Energieversorgung andeutete. Darüber hinaus versuchen sich Institutionen wie das Deutsche Institut für Urbanistik (Difu) und der Verband kommunaler Unternehmen e.V. (VKU) bereits seit Jahren einen Überblick über die Entwicklung von Rekommunalisierungen zu verschaffen. Trotzdem existiert bis heute keine flächendeckende Erhebung über Rekommunalisierungen in Deutschland. Ziel dieser Arbeit war es daher eine Bestandsaufnahme über die Rekommunalisierung von Strom-Verteilnetzkonzessionen im Untersuchungsraum Nordrhein-Westfalen zwischen 2005 und 2016 vorzunehmen. In diesem Zeitraum konnten für den Untersuchungsraum insgesamt 119 Rekommunalisierungen festgestellt werden. Damit lagen bis Ende 2016 bereits zwei Drittel aller nordrhein-westfälischen Strom-Verteilnetzkonzessionen in kommunaler Hand, womit der Trend zur Rekommunalisierung eindeutig belegt werden konnte.

Description: Mit fortschreitender Energiewende steigt der Anteil erneuerbarer Energien im Strommix. Deren Angebot variiert im Tagesverlauf, nach Wetterlage und saisonal. Um Angebot und Nachfrage zur Deckung zu bringen, benötigt es daher Speicher mit großen Kapazitäten. Von allen technologischen Optionen mit großer Speicherkapazität sind Wasser-Pumpspeicherwerke die einzige, die langjährig erprobt und wirtschaftlich ist. Diese könnten in Braunkohletagebauen, welche im Zuge der Energiewende aufgegeben werden, errichtet werden. Unsere Überschlagsrechnung am Beispiel eines Pumpspeicherwerks in den heutigen Tagebauen Hambach, Garzweiler und Inden zeigt, dass diese mit bis zu 400 GWh ein signifikantes technisches Speicherpotenzial haben. Dies entspricht etwa der kontinuierlichen Maximalleistung eines Kernkraftwerks über zwei Wochen. Im Kontext der Diskussion um den Braunkohleausstieg skizziert das Papier ein netzdienliches Nachnutzungskonzept für Braunkohletagebaue, das zumindest für einen Teil der heute in der Kohleförderung und -Verstromung Beschäftigten mögliche Zukunftsperspektiven bietet.

Description: Die vorliegende Arbeit verfolgt die Zielsetzung, den Beitrag verschiedener politischer Handlungsoptionen zur Steigerung der betrieblichen Energieeffizienz zu ermitteln. Eingangs wird aufgezeigt, inwieweit die Steigerung der Energieeffizienz aufgrund ihrer vielfältigen Vorteile eine Einstufung als eigenständige Zielgröße rechtfertigt im Gegensatz zu einer bloßen Betrachtung als Mittel zum Zweck des Klimaschutzes. Für die anschließende quantitative Analyse wurden Daten aus dem Projekt Energieeffizienz Impulsgespräche des Rationalisierungs- und Innovationszentrums der Deutschen Wirtschaft (RKW) e.V. aus den Jahren 2011 bis 2013 mit eigens für diese Arbeit erhobenen Daten von 2017 für dieselben Unternehmen verglichen. Zu diesem Zweck wird ein difference-in-differences-Ansatz genutzt. Im Ergebnis erweisen sich Preise im Gegensatz zu anderen Maßnahmen wie Energieberatungen, Fördermitteln und Energiemanagementsystemen als zumindest teilweise wirksame Einflussgröße für die Energieeffizienz. Der Autor empfiehlt auf dieser Basis eine stärker marktwirtschaftlich ausgerichtete Effizienzpolitik.

Description: Im Rahmen des Forschungsprojekts "Wirtschaftsförderung 4.0" leistet die vorliegende Arbeit einen Beitrag zum besseren Verständnis der systematischen Stärkung zivilgesellschaftlicher Nachhaltigkeitsinitiativen. Das Ziel der Analyse besteht darin, Ansatzpunkte möglicher Unterstützungsmaßnahmen aufzuzeigen, die im Zuge kommunaler Wirtschaftsförderung aufgegriffen werden können. Zur Erarbeitung wurden zunächst mithilfe theoretischer Grundlagen aus der Transition- und Diffusionsforschung zentrale Einflussfaktoren zusammengetragen, die förderlich oder hemmend auf transformative Nachhaltigkeitsinitiativen wirken können. Mit dem Ziel, kontextangepasste Maßnahmen zu entwickeln, wurden die literaturbasierten Faktoren anschließend in einer qualitativen Befragung mit einer Praxisperspektive verglichen und ergänzt: Mittels leitfadengestützter Experteninterviews mit nachhaltigkeitsorientierten Initiativen in der Region Osnabrück wurden kommunale Gegebenheiten sowie die jeweiligen Erfolgsfaktoren, Herausforderungen und Bedarfe der Graswurzelinitiativen erfasst. Im Ergebnis zeigen sich sieben übergreifende Bedarfsfelder, die vor allem aus der empirischen Erhebung abgeleitet wurden. Aus ihnen wurden Handlungsempfehlungen und Ansatzpunkte kommunaler Unterstützung erarbeitet und diskutiert.

Description: Die Autoren verdeutlichen in diesem Papier, dass der Megatrend Digitalisierung nicht zwingend unkontrollierbar über die Wirtschaft und die Gesellschaft hereinbricht. Seine Wirkung hängt vom menschlichen Verhalten, von der Gestaltung neuer Prozessen in Organisationen, aber auch Anpassungen der gesetzlichen Rahmenbedingungen ab. Dieses sozio-kulturelle, organisatorische und institutionelle Umfeld der digitalen Innovationen könne und müsse im Sinne ökologischer Nachhaltigkeit beeinflusst werden. Politik sei hier aufgefordert auf der Basis fundierter Analysen flankierend tätig zu werden. Die Autoren fordern daher, für die Digitalwirtschaft eine eigene sektorspezifische Politik zu entwickeln, wie sie für andere umweltrelevante Sektoren - etwa die Energiewirtschaft, Chemieindustrie oder Autoindustrie - bereits etabliert ist.

Description: Deutschland verfügt über eines der weltweit führenden Systeme im Bereich der Abfallwirtschaft - vorrangiges Ziel ist es, Abfall sicher und umweltschonend zu entsorgen. Allerdings kommen nur ca. 14 Prozent der in der Industrie eingesetzten Rohstoffe aus dem Recycling, der Rest sind noch immer Primärmaterialien. Kreislaufwirtschaft findet noch nicht ausreichend statt: Rezyklate, aus Abfällen gewonnene Sekundärrohstoffe, werden noch weit unterhalb der möglichen Mengen in Produktions- und Nutzungsprozesse zurückführt. Werteverlust, Abhängigkeit von volatilen Rohstoffmärkten, geringere Ressourcenproduktivität und Externalitäten in Form von Umweltverschmutzung ließen sich damit vermeiden. Eine Digitalisierungsoffensive in Industrie und Abfallwirtschaft könnte dies bewirken. Eine Studie des Bundesministeriums für Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB) verweist darauf, dass kein Umweltleitmarkt so stark von der Digitalisierung profitieren könnte wie die Kreislaufwirtschaft - und dass gleichzeitig kein Sektor bisher so schlecht aufgestellt ist.

Description: Allein zwischen 2005 und 2014 haben weit über 100 Städte und Gemeinden in Deutschland eigene Stadtwerke gegründet und ca. 200 Verteilnetze übernommen - dagegen wehren sich drei Energiekonzerne und ein Netzwerk.

Description: The test capabilities of the Stability Wind Tunnel of the Virginia Polytechnic Institute and State University are described, and calibrations for curved and rolling flow techniques are given. Oscillatory snaking tests to determine pure yawing derivatives are considered. Representative aerodynamic data obtained for a current fighter configuration using the curved and rolling flow techniques are presented. The application of dynamic derivatives obtained in such tests to the analysis of airplane motions in general, and to high angle of attack flight conditions in particular, is discussed.

Description: The design and operations of a low cost, high rate thermal cycling facility designed for LEO conditions is described. Thermal cycling facilities were constructed with various design criteria. Some were designed to duplicate as closely as possible the conditions a cell or module would encounter while in orbit about the Earth. A typical facility to perform this type of cycling was a large vacuum system with liquid nitrogen cooled walls. The cells were heated by an AMO spectrum solar simulator, then a shutter was closed allowing the cells to give up their heat to the cold walls. This system was good at duplicating the orbital conditions but was slow and very costly to operate. Other systems used a gas atmosphere and heated the cells with radiant heat and cooled the cells by moving them into close proximity to a cold plate. The systems greatly increased the cycle times. Other systems moved the heating and cooling atmosphere into and out of the test areas and achieved reasonable cycle rates. All these systems, however, are expensive to operate.

Description: The development of the GaAs solar cells for space applications is described. The activities in the fabrication of GaAs solar panels are outlined. Panels were fabricated while introducing improved quality control, soldering laydown and testing procedures. These panels include LIPS II, San Marco Satellite, and a low concentration panel for Rockwells' evaluation. The panels and their present status are discussed.

Description: The solar array for the San Marco D/L spacecraft is described and the performance of 4 GaAs solar cell panels are examined. In comparison to the typical Si solar cell panel for San Marco D/L, it is shown that each GaAs solar cell panel provides at least 23 percent more specific power at maximum output and 28 deg C. Also described here, are several measurements that will be made to evaluate the relative performance of Si and GaAs solar cell panels during the San Marco D/L flight.

Description: The results of heteroepitaxial growth of GaAs and GaAlAs directly on Si are presented, and applications to new cell structures are suggested. The novel feature is the elimination of a Ge lattice transition region. This feature not only reduces the cost of substrate preparation, but also makes possible the fabrication of high efficiency monolithic cascade structures. All films to be discussed were grown by organometallic chemical vapor deposition at atmospheric pressure. This process yielded reproducible, large-area films of GaAs, grown directly on Si, that are tightly adherent and smooth, and are characterized by a defect density of 5 x 10(6) power/sq cm. Preliminary studies indicate that GaAlAs can also be grown in this way. A number of promising applications are suggested. Certainly these substrates are ideal for low-weight GaAs space solar ells. For very high efficiency, the absence of Ge makes the technology attractive for GaAlAs/Si monolithic cascades, in which the Si substrates would first be provided with a suitable p/n junction. An evaluation of a three bandgap cascade consisting of appropriately designed GaAlAs/GaAs/Si layers is also presented.

Description: Deep level transient spectroscopy reveals that the main electron traps for one-MeV electron irradiated GaAs cells are E9c)-0.31, E(c)-0.90 eV, and the main hole trap is due to the level. Electron trap density was found to vary from 3/tens-trillion ccm for 2/one quadrillion cm 3/3.7 quadrillion cm for 21 sextillion cm electron fluence for electron fluence; a similar result was also obtained for the hole trap density. As for the grown-in defects in the Al(x)Ga(1-x)As p-n junciton cells, only two electron traps with energies of E(c)-0.20 and E(c)-0.34 eV were observed in samples with x = 0.17, and none was found for x 0.05. Auger analysis on the Al(x)Ga(1-x) As window layer of the GaAs solar cell showed a large amount of oxygen and carbon contaminants near the surface of the AlGaAs epilayer. Thermal annealing experiment performed at 250 C for up to 100 min. showed a reduction in the density of both electron traps.

Description: A short circuit current (I sub sc) degradation model for gallium arsenide (GaAs) solar cells irradiated by protons from low energy to 100 MeV was developed. This model was found to be satisfactory in predicting the I sub sc degradation of GaAs cells, but not that of silicon (Si) cells. A modification to the aforementioned model that preserves the optical wavelength dependency in the photogeneration of minority carrier pairs was described herein. Spectral Si and GaAs response and I sub sc for the Si and GaAs solar cells were discussed, and also were presented in graph form. The overall predictability of the modified model was deemed to be satisfactory.

Description: Manufacturing technology for mass producing high efficiency GaAs solar cells is discussed. A progress using a high throughput MO-CVD reactor to produce high efficiency GaAs solar cells is discussed. Thickness and doping concentration uniformity of metal oxide chemical vapor deposition (MO-CVD) GaAs and AlGaAs layer growth are discussed. In addition, new tooling designs are given which increase the throughput of solar cell processing. To date, 2cm x 2cm AlGaAs/GaAs solar cells with efficiency up to 16.5% were produced. In order to meet throughput goals for mass producing GaAs solar cells, a large MO-CVD system (Cambridge Instrument Model MR-200) with a susceptor which was initially capable of processing 20 wafers (up to 75 mm diameter) during a single growth run was installed. In the MR-200, the sequencing of the gases and the heating power are controlled by a microprocessor-based programmable control console. Hence, operator errors can be reduced, leading to a more reproducible production sequence.

Description: A KC-135A aircraft equipped with wing tip winglets was flight tested to demonstrate and validate the potential performance gain of the winglet concept as predicted from analytical and wind tunnel data. Flight data were obtained at cruise conditions for Mach numbers of 0.70, 0.75, and 0.80 at a nominal altitude of 36,000 ft. and winglet configurations of 15 deg cant/-4 deg incidence, 0 deg cant/-4 deg incidence, and baseline. For the Mach numbers tested the data show that the addition of winglets did not affect the lifting characteristics of the wing. However, both winglet configurations showed a drag reduction over the baseline configuration, with the best winglet configuration being the 15 deg cant/-4 deg incidence configuration. This drag reduction due to winglets also increased with increasing lift coefficient. It was also shown that a small difference exists between the 15 deg cant/-4 deg incidence flight and wind tunnel predicted data. This difference was attributed to the pillowing of the winglet skins in flight which would decrease the winglet performance.

Description: A joint NASA/USAF program was conducted to accomplish the following objectives: (1) evaluate the benefits that could be achieved from the application of winglets to KC-135 aircraft; and (2) determine the ability of wind tunnel tests and analytical analysis to predict winglet characteristics. The program included wind-tunnel development of a test winglet configuration; analytical predictions of the changes to the aircraft resulting from the application of the test winglet; and finally, flight tests of the developed configuration. Pressure distribution, loads, stability and control, buffet, fuel mileage, and flutter data were obtained to fulfill the objectives of the program.

Description: A full-scale winglet flight test on a KC-135 airplane with an upper winglet was conducted. Data were taken at Mach numbers from 0.70 to 0.82 at altitudes from 34,000 feet to 39,000 feet at stabilized flight conditions for wing/winglet configurations of basic wing tip, 15/-4 deg, 15/-2 deg, and 0/-4 deg winglet cant/incidence. An analysis of selected pressure distribution and data showed that with the basic wing tip, the flight and wind tunnel wing pressure distribution data showed good agreement. With winglets installed, the effects on the wing pressure distribution were mainly near the tip. Also, the flight and wind tunnel winglet pressure distributions had some significant differences primarily due to the oilcanning in flight. However, in general, the agreement was good. For the winglet cant and incidence configuration presented, the incidence had the largest effect on the winglet pressure distributions. The incremental flight wing deflection data showed that the semispan wind tunnel model did a reasonable job of simulating the aeroelastic effects at the wing tip. The flight loads data showed good agreement with predictions at the design point and also substantiated the predicted structural penalty (load increase) of the 15 deg cant/-2 deg incidence winglet configuration.

Description: A joint NASA/U.S. industry program to test advanced technology airfoils in the Langley 0.3-meter Transonic Tunnel (TCT) was formulated under the Langley ACEE Project Office. The objectives include providing U.S. industry an opportunity to compare their most advanced airfoils to the latest NASA designs by means of high Reynolds number tests in the same facility. At the same time, industry would again experience in the design and construction of cryogenic test techniques. The status and details of the test program are presented. Typical aerodynamic results obtained, to date, are presented at chord Reynolds number up to 45 x 10(6) and are compared to results from other facilities and theory. Details of a joint agreement between NASA and the Deutsche Forschungs- und Versuchsantalt fur Luft- and Raumfahrt e.V. (DFVLR) for tests of two airfoils are also included. Results of these tests will be made available as soon as practical.

Description: Various coatings developed in the FRG (i.e., second-surface mirrors with interference filters with and without conductive layers, conductive layers on solar-cell covers, and selective absorber coatings) have been qualified by accelerated tests under simulated space environment conditions. Experiments with coatings and solar cells have shown, however, that the thermo-optical behavior can differ considerably when performed on the ground and in space because of the great difficulty in simulating the space environment realistically. The objective of this experiment is to qualify these coatings under realistic space environment conditions. In addition, the experiment will provide design criteria, techniques, and test methods to insure control of the combined space and spacecraft environment effects, such as contamination, electrical conductance, and optical degradation, on the coatings. Data to be measured include the temperature of the samples, the electrical resistance of the conductive layers of the samples, the short circuit current of the solar-cell modules, and the deposition of contaminants on the samples (using quartz crystal microbalances (QCM's)).

Description: The objective of this experiment is to evaluate the synergistic effects of the space environment on various solar-array materials, including solar cells, cover slips with various antireflectance coatings, adhesive, encapsulants, reflector materials, substrate strength materials, mast and harness materials, structural composites, and thermal control treatments. The experiment is passive and consists of an arrangement of material specimens mounted in a 3-in.-deep peripheral tray. The effects of the space environment on the specimens will be determined by comparison of preflight and postflight measurements of mechanical, electrical, and optical properties.

Description: A model that explains the flat-spot power loss phenomenon is presented. Evidence suggests that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the P-N junction is destroyed and replaced with a metal semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallization are shown along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.

Description: Dynamic model verification is the process whereby an analytical model of a dynamic system is compared with experimental data, adjusted if necessary to bring it into agreement with the data, and then qualified for future use in predicting system response in a different dynamic environment. These are various ways to conduct model verification. The approach taken here employs Bayesian statistical parameter estimation. Unlike curve fitting, whose objective is to minimize the difference between some analytical function and a given quantity of test data (or curve), Bayesian estimation attempts also to minimize the difference between the parameter values of that funciton (the model) and their initial estimates, in a least squares sense. The objectives of dynamic model verification, therefore, are to produce a model which: (1) is in agreement with test data; (2) will assist in the interpretation of test data; (3) can be used to help verify a design; (4) will reliably predict performance; and (5) in the case of space structures, will facilitate dynamic control.

Description: Multidisciplinary analysis often requires optimization of nonlinear systems that are subject to constraints. Trajectory optimization is one example of this situation. The Program to Optimize Simulated Trajectories (POST) was used successfully for a number of problems. The purpose is to describe POST and a new optimization approach that has been incorporated into it. Typical uses of POST will also be illustrated. The projected-gradient approach to optimization is the preferred option in POST and is discussed. A new approach to optimization, the random-walk approach, is described, and results with the random-walk approach are presented.

Description: The purpose is not to provide a detailed discussion of several wall interference experiments, but rather to use these experiments (recently accomplished in the Boeing Transonic Wind Tunnel (BTWT) to illustrate the problems associated with many of the measurements required by current wall interference assessment/correction (WIAC) procedures. The wall correction to lift is emphasized. It is shown that, because conventional tunnels and relatively small models continue to be used, the flow field or flow boundary measurements to be made impose severe requirements on the experiment itself. In some cases, existing instrumentation and test techniques may not be adequate to obtain the data accuracies needed.

Description: Based upon limited, initial observations of wall interference corrections obtained for one airfoil test, there is a need for assessing the upstream flow direction. If there is no direct measurement then a two-pass correction procedure similar to the one described here is required. Questions have arisen pertaining to the correct interpretation of the pressure coefficients measured on the slats of a slotted tunnel wall, the interpretation of just what the calculated equivalent body encompasses or should include, and what can or should be considered as quantitative criteria for data correctability. Further studies using this modified procedure will address these questions. Hopefully, a meaningful WIAC procedure can be validated for the airfoil tests in the 0.3-m TCT.

Description: A series of airfoils were tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel (TCT) at Reynolds numbers from 2 to 50 million. The 0.3-m TCT is equipped with Barnwell slots designed to minimize blockage due to the tunnel flow and ceiling. This design suggests that sidewall corrections for blockage is needed, and that a lifting airfoil produces a change in angle of attack. Sidewall correction methods were developed for subsonic and subsonic-transonic flow. Comparisons of theory with experimental data obtained in the 0.3-m TCT for two airfoils, the British NPL 9510 and the German R-4 are presented. The NPL 9510 was tested as part of the NASA/United Kingdom Joint Aeronautical Program and R-4 was tested as part f the DFVLR/NASA Advanced Airfoil Research Program. For the NPL 9510 airfoil, only those test points that one would anticipate being difficult to predict theoretically are presented.

Description: Representation of the flow around full-scale ships was sought in the subsonic wind tunnels in order to a Hain Reynolds numbers as high as possible. As part of the quest to attain the largest possible Reynolds number, large models with high blockage are used which result in significant wall interference effects. Some experiences with such a high blockage model tested in the NASA Ames 12-foot pressure wind tunnel are summarized. The main results of the experiment relating to wind tunnel wall interference effects are also presented.

Description: The various procedures referred to as wall interference assessment and correction procedures presume the existence of a surface distribution of data (usually static pressure) measured over a surface on or near the tunnel walls for each test point to be assessed. An alternative approach in which a reasonably sophisticated computer model of the test section flow would be fitted parametrically to a sparse set of measured data is presented. The measurements provides line distributions of static pressure near the center lines of the top, side and bottom walls. The development of a test section model incorporating explicit recognition of discrete slots of finite length with controlled flow reentry into the solid wall downstream portion of the tunnel is shown.

Description: The NASA large flexible solar array space shuttle flight experiment is described. The 32 x 4 m wing is deployed from the shuttle bay, and experiments in electrical output, multiple deployment, and structural dynamics are planned. Both 2 x 4 cm and 5.9 x 5.9 cm cell assemblies on the array blanket are evaluated. Safety/hazards provisions are described, including emergency jettison provisions. Ground testing and hardware fabrication are summarized.

Description: A development program to produce 5.9 x 5.9 cm space quality silicon solar cells with a cost goal of 30 $/W is described. Cell types investigated include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm/cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover glass simultaneously is being developed. Results for cell and array tests are given. Large solar arrays that might use cells of this type are discussed.

Description: Objectives and progress in both low concentration ratio (6 to 10) and high concentration ratio ( 100) array developments are summarized. Problems encountered include: thermal control, maldistribution of concentrated sunlight, current busing, and optical surface degradation. The potential advantages over planar arrays are an order of magnitude reduction in per unit cost of power plus increased immunity to radiation damage.

Description: The design and structural properties of a low concentration ratio solar array are discussed. The assembled module consists of six interconnected containers which are compactly stowed in a volume of 3.24 m(3) for delivery to orbit by the shuttle. The containers deploy in accordian fashion into a rectangular area of 19.4 x 68 meters and can be attached to the user spacecraft along the longitudinal centerline of the end container housing. Five rotary incremental actuators requiring about 8 watts each will execute the 180-degree rotation at each joint. Deployable masts (three per side) are used to extend endcaps from the housing in both directions. Each direction is extended by three masts requiring about 780 watts for about 27 minutes. Concentrator elements are extended by the endcaps and are supported by cable systems that are connected between the housings and endcaps. These power generating elements contain reflector panels which concentrate light onto the solar panels consisting of an aluminum radiator with solar cells positioned within the element base formed by the reflectors. A flat wire harness collects the power output of individual elements for transfer to the module container housing harnesses.

Description: Wall interference is made predominant in tunnel models and by wall geometries to facilitate the study of slot flow. The viscous effects in slots are studied by two dimensional measurements of flow. Wall interference is assessed by measuring pressure distributions at two levels near the walls. Interference on lifting delta wings is calculated. Pressure distributions at inner boundaries show basis axisymetries between the pressure side and the suction side, pointing to the necessity of having wider slots on the pressure side.

Description: Classical methods for calculation of wall corrections which are not satisfactory for a number of flows of interest are discussed. To meet these objections, a number of methods were developed which use measurements of the low at or close to the tunnel walls as an outer boundary condition to define wall interference. The development, assessment and application of one such method is summarized.

Description: Measured field data as a boundary condition for calculating the interference flow field were applied. They are divided into two categories. In the first category, the field data must consist of distributions of a single velocity component, and an accurate estimate of the hypothetical free air contribution of the model to this component is required. The differences between measured values and estimated model contributions are attributed to wall interference and they establish the boundary condition. The associated field data measurements are simple, yet the necessary model representation generally is a serious drawback. The second category requires field data which consist of velocity vector distributions at the price of multicomponent measurements, but at the profit that no information at all is required about the model. In solid wall test sections, the price is reduced to virtually zero but the profit remains.

Description: A limited-zone ventilated wall panel was developed for a closed-wall icing tunnel which permitted correct simulation of transonic flow over model rotor airfoil sections with and without ice accretions. Candidate porous panels were tested in the Ohio State University 6- x 12-inch transonic airfoil tunnel and result in essentially interference-free flow, as evidenced by pressure distributions over a NACA 0012 airfoil for Mach numbers up to 0.75. Application to the NRC 12- x 12-inch icing tunnel showed a similar result, which allowed proper transonic flow simulation in that tunnel over its full speed range.

Description: The free-stream interference caused by the flow through the slotted walls of the test sections of transonic wind tunnels has continuously a problem in transonic tunnel testing. The adaptive-wall transonic tunnel is designed to actively control the near-wall boundary conditions by sucking or blowing through the wall. In order to make the adaptive-wall concept work, parameters for computational boundary conditions must be known. These parameters must be measured with sufficient accuracy to allow numerical convergence of the flow field computations and must be measured in an inviscid region away from the model that is placed inside the wind tunnel. The near-wall flow field was mapped in detail using a five-port cone probe that was traversed in a plane transverse to the free-stream flow. The initial experiments were made using a single slot and recent measurements used multiple slots, all with the tunnel empty. The projection of the flow field velocity vectors on the transverse plane revealed the presence of a vortex-like flow with vorticity in the free stream. The current research involves the measurement of the flow field above a multislotted system with segmented plenums behind it, in which the flow is controlled through several plenums simultaneously. This system would be used to control a three-dimensional flow field.

Description: A three-dimensional adaptive-wall wind tunnel experiment was conducted at Ames Research Center. This experiment demonstrated the effects of wall interference on the upwash distribution on an imaginary surface surrounding a lifting wing. This presentation demonstrates how the interference assessment procedure used in the adaptive-wall experiments to determine the wall adjustments can be used to separately assess lift- and blockage-induced wall interference in a passive-wall wind tunnel. The effects of lift interference on the upwash distribution and on the model lift coefficient are interpreted by a simple horseshoe vortex analysis.

Description: A wall interference correction method for closed rectangular test sections was developed which uses measured wall pressures. Measurements with circular discs for blockage and a rectangular wing as a lift generator in a square closed test section validate this method. These measurements are intended to be a basis of comparison for measurements in the same tunnel using ventilated (in these case, slotted) walls. Using the vortex lattice method and homogeneous boundary conditions, calculations were performed which show sufficiently high pressure levels at the walls for correction purposes in test sections with porous walls. In Gottingen, an adaptive test section (which is a deformable rubber tube of 800 mm diameter) was built and a computer program was developed which is able to find the necessary wall adaptation for interference-free measurements in a single step. To check the program prior to the first run, the vortex lattice method was used to calculate wall pressure distributions in the nonadapted test section as input data for the one-step method. Comparison of the pressure distribution in the adapted test section with free-flight data shows nearly perfect agreement. An extension of the computer program can be made to evaluate the remaining interference corrections.

Description: The following areas were addressed: interchangeable test sections in the 0.3-M Transonic Cryogenic Tunnel (TCT); typical airfoil installation; airfoil capability; advanced technology airfoil test (ATAT); effects of the Reynolds number on the normal force coefficient; effects of the Reynolds number on the drag coefficient; and comparison of experimental results with theory.

Description: A formula for the determination of equivalent model geometry with two variables measured at the interface is derived, based on two dimensional subsonic flow. This predicted model profile is a reasonable initial estimate for transonic flow as long as the sonic region does not reach the interface. A general formula is given in two forms. One is in terms of complex variable functions and the other is an integral equation. The complex-function formula has the advantage of using analytic expressions. The integral equation form requires a numerical solution after assuming the model geometry as a polynomial function. Examples are given to illustrate the application of the formulas.

Description: The two body problem was analyzed with a specific drag model. The model treats drag as a force proportional to the vector velocity and inversely proportional to the distance to the center of attraction. The solution is expressed in terms of known functions and is of a simple and compact form. The time of flight is expressed as a quadrature in the true anomaly. The results are: (1) development of a vector differential equation which allows analysis of an infinite number of gravitational and drag models; and (2) obtaining the solution of a linear differential equation using the inverse method of laplace transforms.

Description: Wall interference correction procedures seek to determine the required changes in certain flow or geometric parameters so that the difference between the flow properties at the model's surface in the tunnel and free air are minimized. A transonic and a linear correction procedure were developed for aircraft models. In addition to Mach number and angle of attack corrections, an estimate of the accuracy of the corrections is provided by the transonic correction procedure. Lift, pitching moment and pressure measurements near the tunnel walls are required. The efficiency and accuracy of the correction procedure are improved. Moreover, correction of both the wing and tail angles of attack is allowed. The procedure is valid for transonic as well as subcritical flows. However, for subcritical flows further approximations and simplifying assumptions are made, leading to a very simple and efficient correction procedure.

Description: A facet of a unified tunnel correction scheme which uses wall pressures to determine tunnel induced blockage and upwash is described. With this method, there is usually no need to use data concerning model forces or power settings to find the interference; it follows directly from the pressures and tunnel dimensions. However, highly inclined jets do not produce good pressure signatures and are highly three dimensional, so they must be treated differently. Flow modeling is also discussed.

Description: Wall corrections as a function of wall porosity in the transonic wall interference problem was assessed. Effective porosities primarily for the two dimensional case were established as follows: (1) comparison of experimental data for two geometrically similar models of different chord/height ratio, an overall value of wall porosity could be deduced; (2) theoretical development which allows for unequal porosity for the floor and ceiling and wall boundary pressure measurements, porosities for floor and ceiling could be deduced; (3) a scheme was developed which allowed unequal porosity of floor and ceiling and streamwise varying porosity. The boundary layer development along the perforated floor and ceiling under the influence of the model pressure field, variations in boundary layer thickness underlining the difficulties in deducing meaningful values of wall porosity were determined. Wall boundary pressure measurement, in combination with singularity modelling of the airfoil, was sufficient to yield required information on the wall interference flow without having to establish some value for wall porosity. The singularity modelling of the airfoil initially covered only lift and volume but was extended to include drag and pitching moment, and second order volume term. It is shown by asymptotic transonic small disturbance analysis, that the derived corrections to angle of attack and free stream Mach number are correct to the first order.

Description: The effort to develop classical methods to compute wall interference at transonic speeds is outlined. The two-dimensional theory and three-dimensional development are discussed. Also, some numerical application of the two-dimensional work are indicated. The basic advantages of the asymptotic theory are noted.

Description: A solution for the tunnel wall boundary layer effects for three-dimensional subsonic tunnels is presented. The model potentials are represented with simple singularities placed on the centerline of the tunnel and Laplace's equation in cylindrical coordinates is solved for either the conventional homogeneous slotted-wall boundary condition, the solid-wall viscous boundary condition, or a combination of them. The most pronounced wall boundary layer effect is on solid blockage for completely closed wind tunnels. Boundary layers on the wall reduce the blockage from the solid-wall, no-boundary-layer case in a manner similar to opening slots in a solid wall. Additionally, for solid-wall tunnel configurations, the streamline curvature interference factor is reduced by a significant amount, whereas the lift interference factor at the model station does not depend on the boundary layer parameter. For combination wall configurations, the slot effect of the horizontal walls dominates the viscous effect of the solid sidewalls.

Description: Three experiments suitable for wall interference assessment and evaluation of proposed correction methods are presented. The experiments are: (1) a series of airfoil tests using a newly designed transonic flow facility that employs side-wall boundary layer suction and upper- and lower-wall shaping; (2) tests on a swept airfoil section spanning a solid-wall wind tunnel with fixed contouring on all four walls; and (3) tests on a swept wing of aspect ratio 3 mounted in a solid-wall wind tunnel with fixed flat walls. Each of the experiments provides data on the airfoil sections as well as on the wind tunnel walls. All the experiments were performed in solid wall wind tunnels corrected for boundary layer displacement effects. Although the experiments were performed primarily to evaluate computer code performance, it is believed that they also provide information that can be used to evaluate methods for assessing and correcting wall interference effects.

Description: Sidewall boundary layer effects were investigated by applying partial upstream sidewall boundary layer removal in the Langley 0.3-m transonic cryogenic tunnel. Over the range of sidewall boundary layer displacement thickness of these tests the influence on pressure distribution was found to be small for subcritical conditions; however, for supercritical conditions the shock position was affected by the sidewall boundary layer. For these tests (with and without boundary layer remove) comparisons with predictions of the GRUMFOIL computer code indicated that Mach number corrections due to the sidewall boundary layer improve the agreement for both subcritical and supercritical conditions. The results also show that sidewall boundary layer removal reduces the magnitude of the sidewall correction; however, a suitable correction must still be made.

Description: A validation of a measured boundary condition technique was carried out to demonstrate the feasibility of a wall interference assessment/correction (WIAC) system. An experimental evaluation was also carried out to compare performances of various techniques, to define the number of necessary boundary measurements for accurate assessment/corrections and to define the envelope of test conditions for which accurate assessment/corrections are achieved. The relative merits of a WIAC system and an adaptive wall tunnel are compared. The measurement surface boundary data is performed with a system of two rotating pipes. These pipes sweep out a cylindrical measurement surface near the tunnel walls, approximately one inch from the wall at the closest point. The experimental model was specially designed and fabricated for the adaptive wall experiments. The model is a wing/tail/body configuration with swept lifting surface. The boundary data taken in Tunnel 1T with the rotating pipe system has been shown to offer several attractive features for WIAC code evaluation. Good spatial resolution of measurements is achieved and measurements are made upstream and downstream of the model. Also, two velocity components are determined.

Description: The research undertaken concerning the computation and/or reduction of wall interference follows two main axes: improvement of wall correction determinations, and use of adaptive flexible walls. The use of wall-measured data to compute interference effects is reliable when the model representation is assessed by signatures with known boundary conditions. When the computed interferences are not easily applicable to correcting the results (especially for gradients in two-dimensional cases), the flexible adaptive walls in operation in T2 are an efficient and assessed means of reducing the boundary effects to a negligible level, if the direction and speed of the flow are accurately measured on the boundary. The extension of the use of adaptive walls to three-dimensional cases may be attempted since the residual corrections are assumed to be small and are computable.

Description: Participants expressed more interest in GaAs cells than in Si cells. For silicon cells, the beginning of life efficiency is not a major problem but more research is needed in the end of life efficiency. The beginning of life efficiency of GaAs cells must be brought up to 20% at AMO. More proton damage tests must be conducted. Liquid phase epitaxy technology is current but chemical vapor deposition technology is more flexible. There are no obvious problems in limiting process yields. Technology transfer should occur when market demands are generated.

Description: Principles and design considerations of IR transparent solar arrays are discussed. Optimization of performance of flexible solar arrays was studied. Measured solar absorptance as low as alpha s = 0.59 was achieved which leads to a predicted BOL power density of 182.7 = W/square meters. Advanced array concepts, system level cascaded panels, and transparent rigid panels are proposed and expected benefits discussed.

Description: A number of structurally efficient configurations for wing-type solar arrays are developed by a combination of deepening the planform of the blanket and structure and by partitioning the blanket with battens and frequent attachments to the support structure. This technique reduces the tension required to avoid a low natural frequency for the blanket, and the load reduction results in a lighter structure. The use of three different structures are investigated: the Astromast, the Extendible Support Structure (ESS), and a new beam called the STACBEAM (Stacking Triangular Articulated Compact Beam) and their relative performances are compared. The investigation of the STACBEAM is emphasized because its sequential deployment is more reliable for very long systems, and its linear deployment facilitates local attachments to the blanket and the development of a low mass deployer.

Description: Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.

Description: A miniaturized Cassegrainian concentrator (MCC) solar array system is examined to assess the practicality of assembling the basic MCC element into a total array system capable of producing multi-hundred kilowatts of power for Space Platform/Space Station or other low Earth orbit long lifetime missions. Preliminary mechanical and electrical subsystems are developed in order to determine first order performance characteristics. Results of the study support the feasibility of a 100-kilowatt MCC array system with beginning-of-life (BOL) performance of 160 watts per square meter and 28 W/kg. The performance numbers are based on 20 percent efficient (at operating temperature) solar cells and 0.25-millimeter thick electroformed nickel optics. These performance numbers can be improved upon significantly with the development of higher efficiency solar cells and/or lighter weight optics.

Description: High-efficiency, monolithic, two-color, three-terminal solar cells were fabricated by a novel growth technique, vacuum metal-organic chemical vapor deposition. The technique uses the expensive metal alkyls efficiently and toxic gases sparingly. The fact that the outer chamber is constructed of nonbreakable stainless steel is an attractive safety feature associated with this deposition system.

Description: Computer analysis was used to determine the AMO conversion efficiency of single-junction crystalline cells, two-cell and three-cell crystalline tandem structures operating under 100 suns and at 80 C. For optimally designed devices, the calculated efficiencies are 24% for single-junction cells, 33 to 35% for two-cell tandem structures, and 37 to 39% for three-cell tandem structures. Practical efficiencies are expected to be about 15 relative percentage points lower in each case.

Description: The short-circuit current reduction in GaAs shallow junction heteroface solar cells was calculated according to a simplified solar cell damage model in which the nonuniformity of the damage as a function of penetration depth is treated explicitly. Although the equivalent electron fluence was not uniquely defined for low-energy monoenergetic proton exposure, an equivalent electron fluence is found for proton spectra characteristic of the space environment. The equivalent electron fluence ratio was calculated for a typical large solar flare event for which the proton spectrum is PHI(sub p)(E) = A/E(p/sq. cm) where E is in MeV. The equivalent fluence ratio is a function of the cover glass shield thickness or the corresponding cutoff energy E(sub c). In terms of the cutoff energy, the equivalent 1 MeV electron fluence ratio is r(sub p)(E sub c) = 10(9)/E(sub c)(1.8) where E(sub c) is in units of KeV.

Description: Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.

Description: Telemetry from the Living Plume Shield's gallium arsenide solar panel experiment was evaluated to determine degradation. The data were culled to preclude spurious results from possible shadowing or inaccurate measurements on a cold array. Two independent methods were then used to obtain the maximum power points and the various characteristics of the solar array. Fill factor, open circuit voltage, short circuit current, and series and shunt resistances were examined. The data analysis concluded that, to date, nearly all of the solar array degradation is due to the reduction in the short circuit current.

Description: The radiation tolerance of the following three low resistivity, high voltage silicon solar cells was investigated: (1) the COMSAT MSD (multi-step diffused) cell, (2) the MinMIS cell, and (3) the MIND cell. A description of these solar cells is given along with drawings of their configurations. The diffusion length damage coefficients for the cells were calculated and presented. Solar cell spectral response was also discussed. Cells of the MinMIS type were judged to be unsuitable for use in the space radiation environment.

Description: Gallium Arsenide (GaAs) solar cells are viewed as a potential primary power source on certain future Earth orbiting satellites. However, the relative merits of gallium arsenide over silicon in a space radiation environment are largely unknown because a general degradation model for gallium arsenide does not exist. The results of a test simulating the proton radiation environment existing in a polar orbit and the concomitant effects on GaAs and thin silicon (Si) solar cells are presented. The objectives and methodology of the simulation test were discussed. The electrical characteristics of GaAs and Si solar cells are given in graph form. It was concluded that GaAs cells are viable for use on satellites in low Earth orbit.

Description: Significant discrepancies have been observed between predicted and actual in-orbit silicon solar array degradation in orbits other than LEO (low Earth orbits) and GEO (geosynchronous orbit). These discrepancies have been diagnosed to arise probably from a combination of a lack of appropriate solar cell test data and from inadequacies in the models that relate the unidirectional and mono-energetic proton test data to the omnidirectional flux-energy spectra actually found in orbit. Relative damage coefficients and solar cell power outputs were discussed, and also were presented in graph form. Silicon and gallium arsenide solar cells were considered.

Description: The radiation damage of solar cells has become a prime concern to the U.S. Air Force due to longer satellite lifetime requirements. Flight experiments were undertaken on the Navy Living Plume Shield (LPS) satellite and the NASA/Air Force Combined Release and Radiation Effects Satellite (CRRES) to complement existing radiation testing. Each experiment, the rationale behind it, and its approach and status are presented. The effect of space radiation on gallium arsenide (GaAs) solar cells was the central parameter investigated. Specifications of the GaAs solar cells are given.

Description: A computer program, SCAP2D (Solar Cell Analysis Program in 2-Dimensions), is used to evaluate the Etched Multiple Vertical Junction (EMVJ) and grating solar cells. The aim is to demonstrate how SCAP2D can be used to evaluate cell designs. The cell designs studied are by no means optimal designs. The SCAP2D program solves the three coupled, nonlinear partial differential equations, Poisson's Equation and the hole and electron continuity equations, simultaneously in two-dimensions using finite differences to discretize the equations and Newton's Method to linearize them. The variables solved for are the electrostatic potential and the hole and electron concentrations. Each linear system of equations is solved directly by Gaussian Elimination. Convergence of the Newton Iteration is assumed when the largest correction to the electrostatic potential or hole or electron quasi-potential is less than some predetermined error. A typical problem involves 2000 nodes with a Jacobi matrix of order 6000 and a bandwidth of 243.

Description: Several modifications were made to an infinite solution liquid phase epitaxy system that help fabricate both GaAs-based cells and thin cells that effectively reduce power-to-weight ratio for space applications. The most important development is the multiwell crucible for multilayer growth. Using a split crucible in one system, as many as five layers were grown in succession with varying Al levels and dopants. The structures grown were used to produce thin GaAs cells only 10 to 20 microns thick and also to grow cascade cell components. Results of these studies are presented and their applications to the future development of GaAs-based cells are discussed.

Description: A fabrication process for structurally stable thin solar cell wafers that produce good power output after irradiation is described. The fabrication process is as follows. A 6 mil, circular wafer is oxidized on both sides. One side is then patterned with a rectangular array of holes in the oxide that are nominally 75 mils square and separated by 2 mil spacings. Wells are then etched into the silicon with KOH to a depth of 4 mils, leaving a 2 mil, unetched thickness. Two areas on the surface are left unetched to provide pads for bonding or testing. All oxide is then removed and the rest of the processing is normal; the unetched face is used as the illuminated face. When all other processing is complete, a 2 X 2 cm cell is sawed from the starting wafer leaving a border that is approximately 10 mils wide. The effective thickness, determined by weighing an unmetallized sample, of such a cell is about 2.4 mil.

Description: To determine the low speed performance characteristics of a representative high aspect ratio supercritical wing, two low speed jet transport models were fabricated. A 12-ft. span model was used for low Reynolds number tests in the Langley 4- by 7-Meter Tunnel and the second, a 7.5-ft. span model, was used for high Reynolds number tests in the Ames 12-foot Pressure Tunnel. A brief summary of the results of the tests of these two models is presented and comparisons are made between the data obtained on these two models and other similar models. Follow-on two and three dimensional research efforts related to the EET high-lift configurations are also presented and discussed.

Description: Highlight results are presented from subsonic and transonic pressure measurement studies conducted in the Langley Transonic Dynamics Tunnel on a supercritical wing model representative of an energy efficient transport design. Steady- and unsteady-pressure data were acquired on the upper and lower wing surface at an off-design Mach number of 0.60 and at the design Mach number of 0.78, for a Reynolds number of 2.2 x 10(6) (based on the wing average chord). The model configuration consisted of a sidewall-Mounted half-body fuselage and a semi-span wing with an aspect ratio of 10.76, a leading-edge sweepback angle of 28.8 degrees, and supercritical airfoil sections. The wing is instrumented with 252 static pressure orifices and 164 dynamic pressure gages. Model test variables included wing angle of attack, control-surface mean deflection angle, control-surface oscillating deflection angle and frequency, and phasing between oscillating leading-edge and trailing-edge controls when used together.

Description: The advanced photovoltaics-related experiments for investigating a portion of the solar spectrum and the effect of the space environment on photovoltaics. The information will be used to provide correlation between space and ground testing and also to provide for more accurate performance measurement in the laboratory. Specific objectives of these experiments are to provide information on the performance and endurance of advanced and conventional solar cells, to improve reference standards for photovoltaic measurements, and to measure the energy distribution in the extraterrestrial solar spectrum. Data to be obtained will include temperatures and short-circuit current of the samples. Six-point current-voltage (I-V) characteristics will be obtained for selected samples. These data will be recorded once a day during the flight. Orbit data will be correlated with preflight and postflight measurement of the samples.

Description: Current-voltage curves were calculated for each cell in a cascade structure using a solar cell diode equation and superposition. Terms for the light generated current, diffusion current, space charge recombination current and series and shunt resistance are included. Individual current voltage curves are added in series with ohmic resistance losses for the cell interconnects to obtain the cascade cell performance. Temperature was varied with concentration, using several models, and ranged from 55 C at one Sun to between 80 and 200 C at 100 Suns. A variety of series resistance and internal resistances were used. Coefficients of the diffusion and recombination terms are strongly temperature dependent. The study indicates that maximum efficiency (30%) occurs in the 50 to 100X Sun concentration range, provided series resistance is below 0.015 ohm-sq cm and cell temperature is 80 C at 100 Suns.

Description: Gallium and boron doped silicon solar cells, processed by ion implantation followed by either laser or furnace anneal were irradiated by 1 MeV electrons and their postirradiation recovery by thermal annealing was determined. During the postirradiation anneal, gallium doped cells prepared by both processes recovered more rapidly and exhibited none of the severe reverse annealing observed for similarly processed 2 ohm-cm boron doped cells. Ion implanted furnace annealed 0.1 ohm-cm boron doped cells exhibited the lowest post-irradiation annealing temperatures after irradiation. The drastically lowered recovery temperature is attributed to the reduced oxygen and carbon content of the 0.1 ohm-cm cells. Analysis based on defect properties and annealing kinetics indicates that further reduction in annealing temperature is attainable with further reduction in the silicon's carbon and/or divacancy content after irradiation.

Description: A thin-layer Navier-Stokes code capable of predicting steady-state viscous flows is applied to the transonic flow over a Space Shuttle configuration. The code is written in the generalized coordinate system, and the grid-generation code of Fujii (1983) is used for the discretization of the flow field. The flow-field computation is done using the CRAY 1S computer at NASA Ames. The computed result is physically reasonable, even though no experimental data is available for the comparison purpose.

Description: The present conference on electrochemical power sources encompasses systems of such types as the thermoelectric, advanced rechargeable, lithium reserve, rechargeable, and nonrechargeable, nickel-cadmium and nickel-hydrogen rechargeable, lead-acid, nickel-zinc and nickel-iron rechargeable, nickel-cadmium and nickel-hydrogen rechargeable, and fuel cells. Attention is given to Si-Ge alloy multicouple technology, sodium-sulfur battery development status, the safety aspects of a rechargeable lithium C cell, fiber-structure electrodes for nickel-cadmium batteries, energy density improvements in Li/carbon monofluoride cells, zinc-air button cell technology, catalyzed cathodes for Li/SOCl2 cells, the effect of polymer structure on the rate capability of the lithium-iodine cell, and a methanol fuel cell powerplant.

Description: Previously cited in issue 5, p. 579, Accession no. A83-16536

Description: Previously cited in issue 15, p. 2346, Accession no. A82-31959

Description: A feasibility study has been conducted for a NASA Kennedy Space Center liquid hydrogen/liquid oxygen production facility using solar cell arrays as the power source for electrolysis. The 100 MW output of the facility would be split into 67.6 and 32 MW portions for electrolysis and liquefaction, respectively. The solar cell array would cover 1.65 sq miles, and would be made up of 249 modular 400-kW arrays. Hydrogen and oxygen are generated at either dispersed or centralized water electrolyzers. The yearly hydrogen output is projected to be 5.76 million lbs, with 8 times that much oxygen; these fuel volumes can support approximately 18 Space Shuttle launches/year.