High performance Carnot Batteries based on hybrid cycles

Pumped thermal energy storage (PTES) has seen a rapid increase in research interest and private investment during the last few years. A range of different concepts has been proposed, based on different thermodynamic cycles, and the most promising ones are already being turned into demonstration projects or small-scale storage plants. These include PTES systems based on the Joule-Brayton cycle, the Rankine cycle and the Liquid Air cycle, among others. This presentation will explore how hybridising some of these concepts can result in systems that are more flexible, cheaper, or have superior performance compared with the original cycles. More specifically, two examples will be shown where the Joule-Brayton cycle can be effectively used to support a Rankine battery and a Liquid Air battery. One general advantage of Brayton-PTES systems is that they can use molten salts as liquid storage media. Molten salts are cheap, safe and abundant, and have been used for concentrated solar power (CSP) applications in a large number of commercial plants. Employing the same storage material at similar temperature levels opens the possibility of hybrid “solar-PTES” systems that would require less capital investment than two separate plants. Such a hybrid system could charge the same hot stores using either solar energy or off-peak electricity, becoming both a power plant and an energy storage plant, therefore increasing the capacity factor while employing a single heat engine during discharge. A numerical model has been implemented to study a solar-PTES system where an existing CSP plant (based on the Rankine cycle) is retrofitted with a Brayton heat pump, and several strategies are explored to boost the overall performance. Similar configurations could be employed to transform other kinds of thermal power plant (such as coal power plants) into Brayton-Rankine batteries. In contrast to most PTES systems, liquid air energy storage (LAES) stores most of the available energy cryogenically, by liquefying atmospheric air and storing it at very low temperatures. This is advantageous because liquid air has a very high energy density - and is free. However, the difficulties in reaching full liquefaction during the charge process have a significant impact on the round-trip efficiency of the cycle. It has been found that these difficulties can be greatly minimised by employing the support of a Brayton cycle. A hybrid system was designed where a Brayton-PTES plant operates as a topping cycle and an LAES plant operates as a bottoming cycle. The cooling provided by the Brayton cycle allows the LAES side to achieve full air liquefaction, which translates into a significant boost in performance. Furthermore, the cold thermal reservoirs that would be required by the two separate cycles are replaced by a single heat exchanger that acts between them, therefore saving significant amounts of storage media per unit of energy stored. Results from a numerical study indicate that the hybrid cycle can increase round-trip efficiency by 5-10 percent points compared with the separate cycles, and achieve an even larger increase in terms of energy density

Science-based restoration monitoring of coastal habitats, Volume One: A framework for monitoring plans under the Estuaries and Clean Waters Act of 2000 (Public Law 160-457)

Executive Summary: The Estuary Restoration Act of 2000 (ERA), Title I of the Estuaries and Clean Waters Act of 2000, was created to promote the restoration of habitats along the coast of the United States (including the US protectorates and the Great Lakes). The NOAA National Centers for Coastal Ocean Science was charged with the development of a guidance manual for monitoring plans under this Act. This guidance manual, titled Science-Based Restoration Monitoring of Coastal Habitats, is written in two volumes. It provides technical assistance, outlines necessary steps, and provides useful tools for the development and implementation of sound scientific monitoring of coastal restoration efforts. In addition, this manual offers a means to detect early warnings that the restoration is on track or not, to gauge how well a restoration site is functioning, to coordinate projects and efforts for consistent and successful restoration, and to evaluate the ecological health of specific coastal habitats both before and after project completion (Galatowitsch et al. 1998). The following habitats have been selected for discussion in this manual: water column, rock bottom, coral reefs, oyster reefs, soft bottom, kelp and other macroalgae, rocky shoreline, soft shoreline, submerged aquatic vegetation, marshes, mangrove swamps, deepwater swamps, and riverine forests. The classification of habitats used in this document is generally based on that of Cowardin et al. (1979) in their Classification of Wetlands and Deepwater Habitats of the United States, as called for in the ERA Estuary Habitat Restoration Strategy. This manual is not intended to be a restoration monitoring “cookbook” that provides templates of monitoring plans for specific habitats. The interdependence of a large number of site-specific factors causes habitat types to vary in physical and biological structure within and between regions and geographic locations (Kusler and Kentula 1990). Monitoring approaches used should be tailored to these differences. However, even with the diversity of habitats that may need to be restored and the extreme geographic range across which these habitats occur, there are consistent principles and approaches that form a common basis for effective monitoring. Volume One, titled A Framework for Monitoring Plans under the Estuaries and Clean Waters Act of 2000, begins with definitions and background information. Topics such as restoration, restoration monitoring, estuaries, and the role of socioeconomics in restoration are discussed. In addition, the habitats selected for discussion in this manual are briefly described. (PDF contains 116 pages

Developing and Examining Validity Evidence for the Writing Rubric to Inform Teacher Educators (WRITE)

Assessment is an under-researched challenge of writing development, instruction, and teacher preparation. One reason for the lack of research on writing assessment in teacher preparation is that writing achievement is multi-faceted and difficult to measure consistently. Additionally, research has reported that teacher educators and preservice teaches may have limited assessment literacy knowledge. In previous studies, researchers have struggled to provide strong evidence of validity, reliability, and fairness across raters, writing samples, and rubric items. In the present study, we fill several gaps in the research literature by developing a rubric, the Writing Rubric to Inform Teacher Educators (WRITE), which utilizes a structure that promotes assessment literacy while raters score samples. Furthermore, using modern measurement theory, we strengthen the field’s understanding of writing assessment by providing evidence of validity, reliability, and fairness of scores to support the interpretation and use of the WRITE

The Glial Regenerative Response to Central Nervous System Injury Is Enabled by Pros-Notch and Pros-NFκB Feedback

Organisms are structurally robust, as cells accommodate changes preserving structural integrity and function. The molecular mechanisms underlying structural robustness and plasticity are poorly understood, but can be investigated by probing how cells respond to injury. Injury to the CNS induces proliferation of enwrapping glia, leading to axonal re-enwrapment and partial functional recovery. This glial regenerative response is found across species, and may reflect a common underlying genetic mechanism. Here, we show that injury to the Drosophila larval CNS induces glial proliferation, and we uncover a gene network controlling this response. It consists of the mutual maintenance between the cell cycle inhibitor Prospero (Pros) and the cell cycle activators Notch and NFκB. Together they maintain glia in the brink of dividing, they enable glial proliferation following injury, and subsequently they exert negative feedback on cell division restoring cell cycle arrest. Pros also promotes glial differentiation, resolving vacuolization, enabling debris clearance and axonal enwrapment. Disruption of this gene network prevents repair and induces tumourigenesis. Using wound area measurements across genotypes and time-lapse recordings we show that when glial proliferation and glial differentiation are abolished, both the size of the glial wound and neuropile vacuolization increase. When glial proliferation and differentiation are enabled, glial wound size decreases and injury-induced apoptosis and vacuolization are prevented. The uncovered gene network promotes regeneration of the glial lesion and neuropile repair. In the unharmed animal, it is most likely a homeostatic mechanism for structural robustness. This gene network may be of relevance to mammalian glia to promote repair upon CNS injury or disease

Groundwater Control in Tunneling: Executive Summary

DOT-FH-11-9516This Executive Summary briefly describes a three-volume report on Groundwater Control During Tunneling and in Completed Tunnels

Weight management interventions in adults with intellectual disabilities and obesity: a systematic review of the evidence

o evaluate the clinical effectiveness of weight management interventions in adults with intellectual disabilities (ID) and obesity using recommendations from current clinical guidelines for the first line management of obesity in adults. Full papers on lifestyle modification interventions published between 1982 to 2011 were sought by searching the Medline, Embase, PsycINFO and CINAHL databases. Studies were evaluated based on 1) intervention components, 2) methodology, 3) attrition rate 4) reported weight loss and 5) duration of follow up. Twenty two studies met the inclusion criteria. The interventions were classified according to inclusion of the following components: behaviour change alone, behaviour change plus physical activity, dietary advice or physical activity alone, dietary plus physical activity advice and multi-component (all three components). The majority of the studies had the same methodological limitations: no sample size justification, small heterogeneous samples, no information on randomisation methodologies. Eight studies were classified as multi-component interventions, of which one study used a 600 kilocalorie (2510 kilojoule) daily energy deficit diet. Study durations were mostly below the duration recommended in clinical guidelines and varied widely. No study included an exercise program promoting 225–300 minutes or more of moderate intensity physical activity per week but the majority of the studies used the same behaviour change techniques. Three studies reported clinically significant weight loss (≥ 5%) at six months post intervention. Current data indicate weight management interventions in those with ID differ from recommended practice and further studies to examine the effectiveness of multi-component weight management interventions for adults with ID and obesity are justified