720 research outputs found
On the Consequences of Demographic Change for Rates of Returns to Capital, and the Distribution of Wealth and Welfare
In the industrialized world the population is aging over time, reducing the fraction of the population in working age. Consequently labor is expected to be scarce, relative to capital, with an ensuing decline in the real return on capital. This paper uses demographic projections together with a large scale multi-country Overlapping Generations Model with uninsurable idiosyncratic uncertainty to quantify the distributional and welfare consequences of these changes in factor prices induced by the demographic transition. In our model capital can freely flow between different regions in the OECD (the U.S., the EU and the rest of the OECD). Thus international capital flows may in principle mitigate the decline in rates of returns one would expect in the U.S. if it were a closed economy. We find exactly the opposite. In the U.S. as an open economy, rates of return are predicted to decline by 86 basis points between 2005 and 2080. If the U.S. were a closed economy, this decline would amount to only 78 basis points. This result is due to the fact that other regions in the OECD will age even more rapidly; therefore the U.S. is âimportingâ the more severe aging problem from these regions, especially Europe. A similar conclusion is reached if we let capital flow freely between the OECD and the rest of the world (ROW). While ROW currently has a younger population structure, it is predicted to age even more severely in the next decades, giving rise to an even more pronounced decline in world rates of return to capital. In order to evaluate the welfare consequences of the demographic transition we ask the following hypothetical question: suppose a household economically born in 2005 would live through the economic transition with changing factor prices induced by the demographic change (but keeping her own survival probabilities constant at their 2005 values), how would its welfare have changed, relative to a situation without a demographic transition? We find that households experience significant welfare losses due to the demographic transition, in the order of 2 −5% of consumption, depending on their initial productivity level and the design of the pension system. These losses are mainly due to the fact that lower future returns to capital make it harder for households to save for retirement. On the other hand, if the OECD suddenly opens up to ROW in 2005 and ROW has higher returns to capital before the world capital market integration, then these losses are reduced to 1.5 − 2.5%.
Inequality Trends for Germany in the Last Two Decades: A Tale of Two Countries
In this paper we …rst document inequality trends in wages, hours worked, earnings, consumption, and wealth for Germany from the last twenty years. We generally …nd that inequality was relatively stable inWest Germany until the German uni…cation (which happened politically in 1990 and in our data in 1991), and then trended upwards for wages and market incomes, especially after about 1998. Disposable income and consumption, on the other hand, display only a modest increase in inequality over the same period. These trends occured against the backdrop of lower trend growth of earnings, incomes and consumption in the 1990s relative to the 1980s. In the second part of the paper we further analyze the di¤erences between East and West Germans in terms of the evolution of levels and inequality of wages, income, and consumption.
Assessing the quality of science teachers' lesson plans: Evaluation and application of a novel instrument
Lesson planning is a core part of teachers' professional competence. Written lesson plans play a significant role in science teacher education as a preparation for demonstration lessons during the final teacher certification exam. However, the few existing scoring rubrics on lesson plans are not particularly theoretically sound and are barely tested for the validity of score interpretations. In response to the demand for transparent and applicable criteria, we developed the rubric to assess science lesson plans (RALP) to assess science teachers' lesson plan quality. We employed a mixed-methods approach: First, we present multiple sources of validity evidence (based on test content, internal structure, relations to other variables, and consequences of testing) as mainly quantitative indicators for the quality of the RALP. Based upon that, we applied the RALP to lesson plans written by preservice and trainee science teachers (N = 100) and provided a qualitative analysis of six cases to illustrate common patterns in these lesson plans. Results indicate that teacher educators consider the RALP criteria (N = 24) relevant and objectively applicable. Correlation analyses of the scores and two teacher educators' holistic quality assessment of all lesson plans provide convincing evidence that the RALP can discriminate lesson plan quality levels. Moreover, comparisons between preservice science teachers and trainee science teachers reveal that trainee teachers score significantly higher than preservice teachers, indicating that the RALP is sensitive to differences in teaching and planning experience. The application and in-depth analysis of three criteria of the RALP illustrate these differences in levels of planning quality. We discuss possible applications of the RALP in science teacher education and research in science teaching
Development of an integrated solar-fossil powered steam generation system for industrial applications
Das Poster gibt eine kurze Einführung in das Projekt SolSteam, in dem die Integration solaren Prozessdampfes in einen konventionellen Dampferzeuger untersucht wird
On the Consequences of Demographic Change for Rates of Returns to Capital, and the Distribution of Wealth and Welfare
In the industrialized world the population is aging over time, reducing the fraction of the population in working age. Consequently labor is expected to be scarce, relative to capital, with an ensuing decline in the real return on capital. This paper uses demographic projections together with a large scale multi-country Overlapping Generations Model with uninsurable idiosyncratic uncertainty to quantify the distributional and welfare consequences of these changes in factor prices induced by the demographic transition. In our model capital can freely flow between different regions in the OECD (the U.S., the EU and the rest of the OECD). Thus international capital flows may in principle mitigate the decline in rates of returns one would expect in the U.S. if it were a closed economy. We find exactly the opposite. In the U.S. as an open economy, rates of return are predicted to decline by 86 basis points between 2005 and 2080. If the U.S. were a closed economy, this decline would amount to only 78 basis points. This result is due to the fact that other regions in the OECD will age even more rapidly; therefore the U.S. is âimportingâ the more severe aging problem from these regions, especially Europe. A similar conclusion is reached if we let capital flow freely between the OECD and the rest of the world (ROW). While ROW currently has a younger population structure, it is predicted to age even more severely in the next decades, giving rise to an even more pronounced decline in world rates of return to capital. In order to evaluate the welfare consequences of the demographic transition we ask the following hypothetical question: suppose a household economically born in 2005 would live through the economic transition with changing factor prices induced by the demographic change (but keeping her own survival probabilities constant at their 2005 values), how would its welfare have changed, relative to a situation without a demographic transition? We find that households experience significant welfare losses due to the demographic transition, in the order of 2 −5% of consumption, depending on their initial productivity level and the design of the pension system. These losses are mainly due to the fact that lower future returns to capital make it harder for households to save for retirement. On the other hand, if the OECD suddenly opens up to ROW in 2005 and ROW has higher returns to capital before the world capital market integration, then these losses are reduced to 1.5 - 2.5%.
Contributions of Reelcoop to Concentrating Solar Power
Vortrag über solarthermische Stromerzeugung und Projekte im Bereich solare Prozesswärme, sowie über das Reelcoop Projekt
SolSteam - Integriertes Standardsystem für solar-fossil erzeugten industriellen Prozessdampf
Industrieller Prozessdampf wurde als Marktsegment durch erneuerbare Energien bisher nur sehr wenig ausgeschöpft. Mit konzentrierenden Kollektoren lässt sich Solarenergie auf dem für diese Anwendungen erforderlichen hohen Temperaturniveau effizient nutzen. Besonders vorteilhaft hinsichtlich Investitionskosten und Betriebsverhalten ist die direkte Dampferzeugung im Kollektorsystem. Um sichere Dampfversorgung der Produktionsprozesse unabhängig von der Verfügbarkeit der Solarstrahlung sicherzustellen, ist die Kombination des solaren Dampferzeugers mit einem fossil befeuerten Back-up System sinnvoll. Dies wurde im Projekt SolSteam untersucht und demonstriert.
Zur „Präzisierung der Marktanforderungen“ im AP1 werden für den Temperaturbereich des Hybridsystems (100°C – 500°C) die Branchen Papiergewerbe, chemische Industrie und Ernährungsgewerbe als besonders vielversprechend definiert. Der Dampfkesselmarkt der Industrieländer gilt als gesättigt, während in Ländern mit geringeren Produktionskosten der Markt wächst. Durch steigende Brennstoffkosten steigt die Attraktivität eines Hybridsystems mit Solarenergie. Unter günstigen Bedingungen bezüglich Brennstoffkosten, DNI und Förderquote lassen sich bereits Amortisationen von unter 5 Jahren erreichen.
Im AP2 werden die möglichen Verschaltungen des Wasser-Dampf-Kreislaufs der beiden Systeme betrachtet. Nach einem umfangreichen Screening wurden zwölf mögliche Konzepte identifiziert, aus denen im Ergebnis einer Bewertungsmatrix die drei aussichtsreichsten Konzepte ausgewählt und hierzu die geeigneten Prozessschemata für die kombinierten Lösungen entworfen wurden.
Im Rahmen des AP3 wird eine nach Konzept 2 bereits bestehende Anlage durch eine intensive Umbaumaßnahme um das Konzept 1d ergänzt und mit zusätzlicher Messtechnik soweit ausgestattet, dass ein Monitoring der Anlage als Demonstrator möglich wird. Bei der bereits bestehenden Anlage handelt es sich um ein Hybridsystem aus Fresnel-Kollektor und Dieselkessel, welches bereits seit 2015 erfolgreich Sattdampf bei 4,5 bar für eine pharmazeutische Fabrik in Amman, Jordanien, bereitstellt. Der Fresnel-Kollektor hat eine Aperturfläche von 394 m2 und liefert eine Nennlast von ca. 220 kW. Dabei dient eine 2 m3 Dampftrommel zur Trennung von Wasser und Dampf, als Ausgleichsbehältnis für Verdampfungsvolumen, als Kurzzeitspeicher nach dem Ruths-Speicher-Prinzip und als Druckhaltegefäß für die Solaranlage.
Der Betrieb der solaren Prozessdampfanlage wird im Rahmen des AP4 über einen Zeitraum von 2 Jahren von Ende 2015 bis Ende 2017 überwacht, ausgewertet und dokumentiert. Die Direktverdampfung nach Konzept 2 erweist sich als stabil. In der Regel kann der Druck im Dampfnetz des Verbrauchers sogar konstanter gehalten werden als durch die fossile Dampfbereitstellung. Die Produktionsübergabe zwischen Solarfeld und fossilem Kessel klappt störungsfrei, so dass der Verbraucher durch fluktuierende Sonneneinstrahlung keine Schwankungen in der Versorgung erfährt. Während die Last solar gedeckt wird ist der fossile Kessel in Stand-by.
Aus den Erkenntnissen des AP4 konnten im Rahmen des AP5 Optimierungsansätze erarbeitet und umgesetzt werden
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