Estimating the value of electricity storage in PJM: Arbitrage and some welfare effects

Significant increases in prices and price volatility of natural gas and electricity have raised interest in the potential economic opportunities for electricity storage. In this paper, we analyze the arbitrage value of a price-taking storage device in PJM during the six-year period from 2002 to 2007, to understand the impact of fuel prices, transmission constraints, efficiency, storage capacity, and fuel mix. The impact of load-shifting for larger amounts of storage, where reductions in arbitrage are offset by shifts in consumer and producer surplus as well as increases in social welfare from a variety of sources, is also considered.     

Digitized neutron imaging with high spatial resolution at a low power research reactor: Applications to steel and rock samples

Improved spatial detector resolution is exploited for engineering and geology, e.g., for the investigation of boron distribution in steel, consolidated aspects of building materials, and grain analysis in feldspar. The strengths and limitations of the upgraded instrument are evaluated in the context of these projects. First promising results have been obtained and will extend the range of applications for the neutron imaging beam-line at the Atomic Institute in Vienna.     

Prediction of Martensite Start Temperature for Lightweight Fe-Mn-Al-C Steels

A tailor-made thermodynamic database of the Fe-Mn-Al-C system was developed using the CALPHAD approach. The database enables predicting phase equilibria and thereby assessing the resulting microstructures of Fe-Mn-Al-C alloys. Available information on the martensite start (M_s) temperature was reviewed. By employing the M_s property model in the Thermo-Calc software together with the new thermodynamic database and experimental M_s temperatures, a set of model parameters for the Fe-Mn-Al-C system in the M_s model was optimised. Employing the newly evaluated parameters, the calculated M_s temperatures of the alloys in the Fe-Mn-Al-C system were compared with the available measured M_s temperatures. Predictions of M_s temperatures were performed for the alloys, Fe-10, 15 and 20 wt.% Mn-xAl-yC. The predictability of the M_s model can be further validated when new experimental M_s temperatures of the Fe-Mn-Al-C system are available.     

A swift Quantitative Microbiological Risk Assessment (sQMRA) tool

Classical full-scale QMRA is a valuable method to assess the effects of control measures on the public health risk of a pathogen–food product combination. However, development of these QMRA models is time consuming, data needs are substantial and it requires extensive modeling expertise. We therefore developed a simplified QMRA model especially aimed at comparing the risk of pathogen–food product combinations. The swift Quantitative Microbiological Risk Assessment (sQMRA) – tool is implemented in Microsoft Excel. Special attention is given to make the sQMRA tool insightful, for educational purposes. Like in full-scale QMRA, pathogen numbers are followed through the food chain, which in this case starts at retail and ends with the number of human cases of illness. The model is deterministic and includes cross-contamination and preparation (heating) in the kitchen and a dose–response relationship. The general setup of the sQMRA tool consists of consecutive questions for values of each of the 11 parameters, always followed by intermediate model output broken down into categories of contamination, cross-contamination and preparation. In a separate sheet, model input and output are summarized and exposure as well as cases are attributed to the distinguished categories. As a relative risk measure, intermediate and final model outputs are always compared with results from a full-scale QMRA of Campylobacter on chicken fillet. Example calculations with the sQMRA-tool were done for all combinations of Campylobacter spp. and Salmonella spp. with chicken fillet, filet americain (raw minced beef with mayonnaise) and table eggs. Data availability appeared to be partly poor. The predicted risk was highest for Salmonella spp. in table eggs and Campylobacter spp. in chicken fillet. Results indicate that the sQMRA-tool is useful for quickly obtaining relative risk estimates of pathogen–food combinations. It can thus serve as a guide for selection of combinations for applying full-scale QMRA, or for risk management – by facilitating the translation of the results of trend analysis or of a specific research project into terms of risk.     

柏林中央火车站

在曾为选帝侯冯伯兰登堡狩猎场的洪堡港以西,一个集长途交通、地区交通及短途交通于一身的欧洲最大的火车站:新的柏林中央火车站,已竣工于它的历史故址.东西向呈弧线的铁道线与地下南北向的新城际快车线交汇于此;2个方向上的轻轨和连接南北的地铁也在此相交.南北向的轨道线通向地下15m的隧道,向前横穿施普雷河和提尔加藤区.这里被建设成一个地下的长途火车站,它拥有8条长途交通轨道,4个为长途车次和区域间车次设置的站台.在与东面的长途轨道相平行位置,地铁U5线的新地铁站也成形于此.东两向的轨道线相对于街面被抬高10m,与现有的铁轨持平.在4条新的市内铁路桥上总共建设了4条长途交通轨道和2条轻轨轨道.预计到2010年,进出柏林的长途客流量将达到5000万人次,而包括周边地区在内的区域间交通流量将达到8500万人次.对于柏林中央火车站来说,这意味着年客流量3000万人次,或者每天2.5万人次的客流量.     

The Relation Between Brain Activity During Memory Tasks and Years of Education in Young and Older Adults.

Higher education is associated with less age-related decline in cognitive function, but the mechanism of this protective effect is unknown. The authors examined the effect of age on the relation between education and brain activity by correlating years of education with activity measured using functional MRI during memory tasks in young and older adults. In young adults, education was negatively correlated with frontal activity, whereas in older adults, education was positively correlated with frontal activity. Medial temporal activity was associated with more education in young adults but less education in older adults. This suggests that the frontal cortex is engaged by older adults, particularly by the highly educated, as an alternative network that may be engaged to aid cognitive function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transition metals to sulfur binding energies relationship to catalytic activities in HDS: back to Sabatier with first principle calculations

We have undertaken systematic calculations of transition metal sulfides bulk crystal structures, electronic and energetic properties at the first principles level (DFT, GGA, PW-USPP, PBC, implemented in the Vienna Ab initio Simulation Package, VASP). Relaxed cell parameters and ionic positions showed an excellent agreement with the experimental values. Computed and experimental cohesive energies agreed within 3%. We re-defined the metal–sulfur (M–S) bond strength as the cohesive energy per metal–sulfur bond: we show that all experimental HDS activities (Pecoraro and Chianelli, 1981) fit nicely on a single volcano master curve when plotted against this simple energetic parameter. Metallic (i.e. zero gap) ionic sulfides consistently exhibit the weakest M–S bonds and semi-conductor iono-covalent sulfides the strongest. However, the Sabatier principle suggests a simple kinetic interpretation of this master curve. This new interpretation also accounts for the well known synergetic effects in mixed sulfides and therefore opens new prospects for exploratory applied research.