Evaluating demand side measures in simulation models for the power market

Increased energy efficiency is one of the pillars for reducing CO₂ emissions. However, in models for the electricity market like unit commitment and dispatch models, increased efficiency of demand results in a paradoxical apparent reduction of the total economic surplus. The reason is that these are partial models for the electricity market, which do not take into account the effect of the changes in other markets. This paper shows how the calculation of the consumer surplus in the electricity market should be corrected to take into account the effect in other markets. In different cases we study shifts in the demand curve that are caused by increased energy efficiency, reduced cost for substitutes to electricity and real-time monitoring of demand, and we derive the necessary correction. The correction can easily be included in existing simulation models, and makes it possible to assess the effect of changes in demand on economic surplus.     

On attempts to measure the tenderness of Longissimus Dorsi muscles using fluorescence emission spectra

Autofluorescence spectra have been obtained on beef longissimus dorsi muscles (n=151), and the spectra regressed against Warner-Bratzler (WB) peak values. The spectra obtained depended on the method used, and it is suggested that the difference is related to the use of two different types of Xenon lamps (a pulsed versus a continuous light source) and the inherent kinetic differences in the collection of the fluorochromes' emitted light. Poor to good (R=0.45-0.84) correlations between WB peak values and the emission spectra were obtained. This relationship is established using chemical information originating largely from collagens. Minor differences in predictability were observed using either excitation wavelengths 332 or 380?nm. The emission wavelengths containing the most relevant information about WB peak values were between 360 and 500 nm. Wavelengths around 375 nm, excitation 332 nm, were in particular important and were related to a component in the perimysial tissue, most likely being present in collagen I or III. Excitation at 380?nm revealed the wavelength range 460-480?nm as important presumed due to collagens in the perimysium. An experiment, simulating industrial routines, using 45 samples collected at the slaughterhouse two days post mortem, was carried out. However, for those samples no model was observed between the emission spectra and WB peak values. Only when some samples having very low (相似文献   

铝电解中二氧化锡基（氢气）气体阳极

开发一种在低温电解质（850℃）铝电解中应用的新型二氧化锡基气体阳极以降低铝电解能耗和二氧化碳排放。在此种气体阳极中,氢气通入阳极后参与阳极反应,分别用石墨和铝作阴极和参比电极。采用循环伏安法研究此体系中铂和二氧化锡基电极上氧离子的电化学行为,并确定氧气的析出电势。然后,采用气体电极进行恒电流电解实验,相对于未通入气体和通入氩气,通入氢气后阳极出现明显的去极化现象（阳极电势约下降0.8 V）。实验结果表明,氢气已参与阳极三相界面（气体-电解质-电极）反应,为还原性气体阳极在铝电解上的应用提供了可行性。     

Exploring the gap between ‘best knowledge’ and ‘best practice’ in boundary layer meteorology for offshore wind energy

Onshore wind turbine technology is moving offshore, and the offshore wind industry tends to use larger turbines than those used over land. This calls for an improved understanding of the marine boundary layer. The standards used in the design of offshore wind turbines, particularly the rotor–nacelle assembly, are similar to those used for onshore wind turbines. As a result, simplifications regarding the marine boundary layer are made. Atmospheric stability considerations and wave effects, including the dynamic sea surface roughness, are two major factors affecting flow over sea versus land. Neutral stratification and a flat, smooth sea surface are routinely used as assumptions in wind energy calculations. Newly published literature in the field reveals that the assumption of a neutral stratification is not necessarily a conservative approach. Design tests based on neutral stratification give the lowest fatigue damage on the rotors. Turbulence, heat exchange and momentum transfer depend on the sea state, but this is usually ignored, and the sea surface is thought of as level and smooth. Field experiments and numerical simulations show that during swell conditions, the wind profile will no longer exhibit a logarithmic shape, and the surface drag relies on the sea state. Stratification and sea state are parameters that can be accounted for, and they should therefore be considered in design calculations, energy assessments and power output predictions. Copyright © 2012 John Wiley & Sons, Ltd.     

Non-destructive determination of fat,moisture and protein in salmon fillets by use of near-infrared diffuse spectroscopy

Near infrared (NIR) diffuse spectroscopy was used to determine the fat, moisture and protein contents in whole and ground farmed atlantic salmon fillets. A remote fibre-optic probe was used for NIR measurements on 50 whole salmon fillets. The constituent ranges were: 91-205 g kg^?1 fat, 599-709g kg^?1 moisture and 186-209 g kg^?1 protein. Principal component regression resulted in the following prediction errors for ground salmon fillets, expressed as root mean square error of cross validation: 6.6 g kg-1 fat, 3.8 g kg^?1 moisture and 2.0 g kg^?1 protein. The corresponding prediction errors for non-destructive measurements on whole salmon fillets were 10.8 g kg^?1 fat, 8.5 g kg^?1 moisture and 3.7 g kg^?1 protein. Regression models using the 760-1100 m range gave lower prediction errors than models using the 1100-2500 mm or 760-2500 nm ranges. The results show that fibre-optic probe NIR instruments are suited to determine fat and moisture in whole salmon fillets non-destructively.     

Loss of safety assessment and the IEC 61508 standard

The standard IEC 61508 contains a lot of useful information and guidance for safety improvement regarding the use of safety systems. However, some of the basic concepts and methods for loss of safety quantification are somewhat confusing. This paper discusses the failure classification, the various contributions to the safety unavailability, and in particular the common cause failure (CCF) model presented in this standard. Suggestions for clarifications and improvements are provided. In particular, a new CCF model is suggested, denoted the Multiple Beta Factor model.     

Health consequences of reduced daily cigarette consumption

Objective

To determine the risk of dying from specified smoking‐related diseases and from any cause in heavy smoking men and women (⩾15 cigarettes/day), who reduced their daily cigarette consumption by >50%.

Design

A prospective cohort study.

Setting

Three counties in Norway.

Participants

24 959 men and 26 251 women, aged 20–49 years, screened for risk factors of cardiovascular disease in the mid‐1970s, screened again after 3–13 years, and followed up throughout 2003.

Outcomes

Absolute mortality and relative risks adjusted for confounding variables, of dying from all causes, cardiovascular disease, ischaemic heart disease, all smoking‐related cancer and lung cancer.

Results

With sustained heavy smokers as reference, the smokers of both sexes who reduced their daily consumption (reducers) had the following adjusted relative risks (95% confidence interval (CI)): of dying from any cause, 1.02 (0.84 to 1.22); cardiovascular disease, 1.02 (0.75 to 1.39); ischaemic heart disease, 0.96 (0.65 to 1.41); smoking‐related cancer, 0.86 (0.57 to 1.29); and lung cancer, 0.66 (0.36 to 1.21). The difference in cigarette consumption between two examinations was not a significant predictor of death from any of the causes. A follow‐up from a third screening of the subgroup who were reducers at both second and third examinations (sustained reducers) did not have a lower risk than those who were heavy smokers at all three examinations.

Conclusions

Long‐term follow‐up provides no evidence that heavy smokers who cut down their daily cigarette consumption by >50% reduce their risk of premature death significantly. In health education and patient counselling, it may give people false expectations to advise that reduction in consumption is associated with reduction in harm.Does reduced daily cigarette consumption lead to lower mortality from the serious health consequences of cigarette smoking? In other words, does a reduction in consumption bring about reduction in harm?Numerous population studies have given ample evidence that quitting smoking entirely results in a marked reduction in the ill effects of smoking. Up to now, however, only one large prospective study has explored the long‐term effects of unassisted reduced smoking. Godtfredsen et al^1,2,3,4 have pioneered in this field by following up a population of nearly 20 000 men and women living in Copenhagen, Denmark (the Copenhagen Centre for Prospective Population Studies). After mean observation periods ranging from 13.8 to 18 years, they published their results in a series of articles.The aim of this paper is to determine the risk in heavy smokers who reduced their cigarette consumption by at least 50%, named “reducers”, compared with those who continued as heavy smokers. We report on a Norwegian population of 51 210 men and women, aged 20–49 years, who were examined in the mid‐1970s for cardiovascular disease risk factors and were examined again during the next 3–13 years at least once. These people were followed up throughout 2003 for deaths from serious smoking‐related diseases and from all causes. The mean observation period is 21.2 years, maximum 27 years. A subgroup attended three screenings. This gave us the possibility to compare those who were reducers at the two last screenings (sustained reducers) with those who were heavy smokers at all three screenings (sustained heavy smokers).     

Natural fluctuations of mercury and lead in Greenland lake sediments

Given the current scenario of increasing global temperatures, it is valuable to assess the potential influence of changing climate on pollution distribution and deposition. In this study we use long-term sediment records from three lakes (spanning ca. 1000, 4800, and 8000 years, respectively) from the Greenland west coast to assess recent and long-term variations in mercury (Hg) and lead (Pb), including stable Pb isotopes (206Pb and 207Pb), in terms of pollution and climate influences. The temporal trends in sediment deposited from about the mid-19th century and forward are in general agreement with the history of industrial emissions at lower latitudes. Therefore, in recent sediment a possible influence from changing climate is difficult to assess. However, by using deeper sediment layers we show that changes in Greenland climate caused changes in the lake influx of material from regional aeolian activity, which resulted in large fluctuations in Hg and Pb concentrations and 206Pb/207Pb ratios. The aeolian material is primarily derived from glacio-fluvial material with low Hg and Pb concentrations and a different isotopic composition. For one of the lakes, the fluctuations in Hg concentrations (10 to 70 ng g(-1)) prior to the 19th century are equal to the anthropogenic increase in the uppermost layers, suggesting that when studying recent concentrations and time trends of pollution in relatively low-contaminated areas such as the Arctic, the early natural fluctuations must be considered.