Effect of SO2 and steam on CO2 capture performance of biomass-templated calcium aluminate pellets

Four types of synthetic sorbents were developed for high-temperature post-combustion calcium looping CO2 capture using Longcal limestone. Pellets were prepared with: lime and cement (LC); lime and flour (LF); lime, cement and flour (LCF); and lime, cement and flour, doped with seawater (LCFSW). Flour was used as a templating material. All samples underwent 20 cycles in a TGA under two different calcination conditions. Moreover, the prepared sorbents were tested for 10 carbonation/calcination cycles in a 68-mm-internal-diameter bubbling fluidized bed (BFB) under three environments: with no sulphur and no steam; in the presence of sulfur; and with steam. When compared to limestone, all the synthetic sorbents exhibited enhanced CO2 capture performance in both a TGA and BFB, with the exception of the sample doped with seawater. In the BFB tests, the addition of cement binder during the pelletisation process resulted in the increase of CO2 capture capacity from 0.08 gCO2/gsorbent (LF) to 0.15 gCO2/gsorbent (LCF) by the 10th cycle. The CO2 uptake in the presence of SO2 dramatically declined by the 10th cycle; for example, from 0.22 gCO2/gsorbent to 0.05 gCO2/gsorbent in the case of the untemplated material (LC). However, as expected all samples showed improved performance in the presence of steam and the decay of reactivity during the cycles was less pronounced. Nevertheless, in the BFB environment, the templated pellets showed poorer CO2 capture performance. This is presumably because of material loss due to attrition under the FB conditions. Namely, by contrast, the templated materials performed better than untemplated materials under TGA conditions. This indicates that reduction in attrition is critical in the case of employment of templated materials in realistic systems with FB reactors

Governance in Areas of Limited Statehood: The NGOization of Palestine

In this article we examine the shifting roles played by non-state actors in governing areas of limited statehood. In particular we focus on the emergence of voluntary grassroots organizations in Palestine and describe how regimes of international development aid transformed these organizations into professional non-governmental organizations (NGOs) that created new forms of colonial control. Based on in-depth interviews with 145 NGO members and key stakeholders and a historical analysis of limited statehood in Palestine, we found that social relations became disembedded from the local context and re-embedded in new relations with international donor organizations resulting in a depoliticized public sphere. NGOization of the economy also resulted in new forms of exclusion and inclusion as well as contestations between a new class of urban middle class professionals working in NGOs and the older generation of activists that were involved in grassroots organizations. Our findings have implications for business and human rights and governance in areas of limited statehood, in particular how private actors like NGOs are able to exercise power in the economy

Berücksichtigung lokaler Werkstoffeigenschaften bei der Modellierung von Schweißnähten zum Nachweis der Ermüdungsfestigkeit

Für den rechnerischen Ermüdungsfestigkeitsnachweis im Kurzzeitfestigkeitsbereich für Schweißnähte soll untersucht werden, ob bei der Simulation der Schweißnähte die Berücksichtigung des lokalen elastisch-plastischem Werkstoffverhalten notwendig ist. Dazu wird ein Kreuzstoß mit abnehmendem Detailierungsgrad bezüglich Geometrie und Werkstoffverhalten modelliert. Anschließend werden die ermittelten maximalen Vergleichsspannungen und maximalen plastischen Vergleichsdehnungen verschiedener Laststufen miteinander verglichen. Dabei zeigt sich, dass die Berücksichtigung der lokalen Werkstoffeigenschaften einen starken Einfluss auf die ermittelte maximale Vergleichsspannung hat. Je detaillierter das Modell nachgebildet wird, desto geringer ist die maximale Vergleichsspannung des gewählten Bauteils

Bestimmung zyklischer Werkstoffkennwerte für Schweißnähte basierend auf der Härte

For fatigue strength verification in the low cycle fatigue for welds, it is necessary to consider elastic-plastic material behaviour. For this purpose, cyclic material properties can be determined experimentally or estimated from static material properties. The experimental determination of weld seams is possible only with very high effort, because no homogeneous specimens can be taken out of weld seams. For the same reason it is not possible to estimate the cyclic characteristic values from the tensile strength. Instead the microhardness of the different areas of the base metal, heat-affected zone and weld metal can be measured using the Vickers method and from this the cyclic properties for the different weld seam areas can be estimated. Various existing estimation methods are investigated and modified for the Vickers hardness input parameter

Reinvigorating international climate policy: a comprehensive framework for effective nonstate action

As countries negotiate a new climate agreement for the United Nations climate conference in December 2015, a groundswell of climate actions is emerging as cities, regions, businesses and civil society groups act on mitigation and adaptation, independently, with each other and with national governments and international organizations. The Paris conference provides a historic opportunity to establish a framework to catalyse, support, and steer these initiatives. Without such a framework, ‘bottom‐up’ climate governance runs the risk of failing to deliver meaningful results. Social science research highlights the need for a comprehensive approach that promotes ambition, experimentation and accountability, and avoids unnecessary overlaps. This article specifies functions and design principles for a new, comprehensive framework for sub‐ and nonstate climate actions that could provide effective coordination