The regulation capability that may be provided by the individual small-scale distributed energy resources (DER power units) may be insignificant. However, the aggregated response from a large number ...of DER power units can be significant and thereby provide valuable system services to the power system. A challenge is to find a cheap, simple and robust way to requests the proper power regulation by the DER power units. The use of broadcasted, dynamic power prices and volunteer responses is one option. The paper presents a proposal for and an illustration of advanced generation of local, dynamic electricity prices for indirect control of active power. The local, dynamic electricity prices are realised as dynamic adjustments of the quasi-stationary global power price. The aims of the dynamic price adjustments are to prevent overloading of the grid, to reduce the grid power losses and to regulate the grid voltage. The algorithms generating the local prices are dynamically adjusted according to the actual realised responses to the dynamic prices. Results are presented from an adapted version of the control principle implemented and tested in DTUs experimental research power system, SYSLAB, including wind power, solar power, flexible load and electrical storage. The local power price generation is based on the actual Nord Pool DK2 Spot prices on hourly basis as the quasi-stationary global electricity price, and the local SYSLAB's power exchange with the national grid as basis for the dynamic price adjustment. (4 pages)
Manufactured nanomaterials (MNMs) often have a surface-chemical modification in order to tailor their physicochemical properties, including also powder properties and miscibility. Surface-chemical ...modifications may influence the toxicological properties of the MNM, but the specific chemistry and extent are rarely described in detail in suppliers' technical data sheets. Chemical and quantitative information on any surface-chemical treatment, coating and functionalization are required for chemicals registration in Europe. Currently there is no globally accepted and documented approach to generate such data. Consequently, there is a continued research need to establish a structured approach to identify and quantify surface-chemical modifications. Here we present a tiered approach starting with screening for mass-loss during heating in a furnace or thermogravimetric analysis (TGA) followed by solvent extraction, and analysis by several mass spectrometry (MS) techniques depending on the target analytes. Thermal treatment was assumed to be able to quantify the amount of organic coating and MS was used to identify the extractable organic coatings after pressurized liquid extraction (PLE) using methanol at 200 °C. Volatile organic compounds in extracts were identified with gas chromatography and MS (GC-MS), non-volatile organic compounds with liquid chromatography MS (LC-MS), and polymeric compounds with matrix-assisted laser desorption ionization time-of-flight MS (MALDI-TOF-MS). The approach was demonstrated by analysis of 24 MNM, comprising titanium dioxide, synthetic amorphous silica, graphite, zinc oxide, silver, calcium carbonate, iron oxide, nickel-zinc-iron oxide, and organoclay. In extracts of 14 MNMs a range of organic compounds were identified and the main groups were silanes/siloxanes, fatty acids, fatty acid esters, quaternary ammonium compounds and polymeric compounds. In the remaining 10 MNMs no organic compounds were detected by MS, despite the fact an organic coating was indicated by TGA.
Volatile Organic Compounds (VOCs) emission and Secondary Organic Aerosols (SOA) formation from a water-based carpet deodorizer were investigated in a 20 m3 walk-in climate chamber with and without a ...textile carpet installed. The deodorizer was tested under near-realistic user conditions at low (<2 ppbv) and high (∼50 ppbv) ozone concentrations and controlled micro-environmental parameters. Fifty grams of the deodorizer was pump sprayed onto 2 m2 inert stainless steel surface or carpet in order to mimic normal use. Characterization of primary VOCs and ozone-initiated products was performed by air sampling on Tenax TA followed by TD-GC/MS analysis and on DNPH cartridges followed by liquid extraction and HPLC/UV analysis. SOA formation was monitored simultaneously by means of high-time resolution instruments. Emission testing onto steel plates at ∼50 ppbv ozone showed the decay of reactive VOCs (i.e., dihydromyrcenol and linalool) concurrent with the consumption of ozone and formation of oxygenated reaction products (i.e., acetaldehyde, acetone and 6-methyl-5-hepten-2-one) and an increase of SOA. Emission testing on carpet at ∼50 ppbv ozone showed a significant ozone removal and an increase of nonanal and dodecanal, but without detection of oxygenated products and SOA formation. Modeling of the reactive VOCs from the carpet experiment showed they followed a first order decay.
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•Fragranced products may produce oxygenated compounds in ozone-enriched environments.•VOCs emission and SOA formation from a carpet deodorizer were investigated.•Oxygenated reaction products and SOA formation was observed at high ozone level.•Carpet showed a significant ozone removal due to a high deposition rate.•Surface interaction between carpet and ozone resulted in aliphatic aldehydes emission.
While there are numerous hypotheses concerning glacial–interglacial environmental and climatic regime shifts in the Arctic Ocean, a holistic view on the Northern Hemisphere's late Quaternary ...ice-sheet extent and their impact on ocean and sea-ice dynamics remains to be established. Here we aim to provide a step in this direction by presenting an overview of Arctic Ocean glacial history, based on the present state-of-the-art knowledge gained from field work and chronological studies, and with a specific focus on ice-sheet extent and environmental conditions during the Last Glacial Maximum (LGM). The maximum Quaternary extension of ice sheets is discussed and compared to LGM. We bring together recent results from the circum-Arctic continental margins and the deep central basin; extent of ice sheets and ice streams bordering the Arctic Ocean as well as evidence for ice shelves extending into the central deep basin. Discrepancies between new results and published LGM ice-sheet reconstructions in the high Arctic are highlighted and outstanding questions are identified. Finally, we address the ability to simulate the Arctic Ocean ice sheet complexes and their dynamics, including ice streams and ice shelves, using presently available ice-sheet models. Our review shows that while we are able to firmly reject some of the earlier hypotheses formulated to describe Arctic Ocean glacial conditions, we still lack information from key areas to compile the holistic Arctic Ocean glacial history.
•A review on the Arctic Ocean glacial history based on state-of-the-art knowledge.•New results and published Arctic ice sheet reconstructions are discussed.•Maximum Quaternary extension of ice sheets is discussed and compared to LGM.
The soil sorption coefficient (Kd) of glyphosate mainly controls its transport and fate in the environment. Laboratory-based analysis of Kd is laborious and expensive. This study aimed to test the ...feasibility of visible near-infrared spectroscopy (vis–NIRS) as an alternative method for glyphosate Kd estimation at a country scale and compare its accuracy against pedotransfer function (PTF). A total of 439 soils with a wide range of Kd values (37–2409 L kg−1) were collected from Denmark (DK) and southwest Greenland (GR). Two modeling scenarios were considered to predict Kd: a combined model developed on DK and GR samples and individual models developed on either DK or GR samples. Partial least squares regression (PLSR) and artificial neural network (ANN) techniques were applied to develop vis–NIRS models. Results from the best technique were validated using a prediction set and compared with PTF for each scenario. The PTFs were built with soil texture, OC, pH, Feox, and Pox. The ratio of performance to interquartile distance (RPIQ) was 1.88, 1.70, and 1.50 for the combined (ANN), DK (ANN), and GR (PLSR) validation models, respectively. vis–NIRS obtained higher predictive ability for Kd than PTFs for the combined dataset, whereas PTF resulted in slightly better estimations of Kd on the DK and GR samples. However, the differences in prediction accuracy between vis–NIRS and PTF were statistically insignificant. Considering the multiple advantages of vis–NIRS, e.g., being rapid and non-destructive, it can provide a faster and easier alternative to PTF for estimating glyphosate Kd.
Arterial stiffness and subclinical coronary atherosclerosis may yield valuable information on cardiovascular risk. We aimed to characterize coronary atherosclerosis in asymptomatic patients with type ...2 diabetes and healthy controls and to investigate the association between baseline arterial stiffness and coronary plaque volumes after 5-year follow-up.
Data from 45 patients and 61 matched controls were available for coronary plaque assessment. For analysis including carotid-femoral pulse wave velocity (PWV), 43 patients and 55 controls were available. At follow-up, mean (SD) age of participants was 63 ± 10 years, and mean diabetes duration (SD) in the patient group was 7.8 ± 1.4 years. Arterial stiffness (PWV) was assessed by tonometry at both visits. Total, calcified, noncalcified, low-density noncalcified coronary plaques volumes and other plaque characteristics were assessed by coronary computed tomography angiography at follow-up.
Despite of similar or better blood pressure and plasma lipid control, patients had, compared with controls, a higher number of plaques with spotty calcifications (P < 0.01) and remodeling index more than 1.1 (P < 0.05), larger calcified plaque volumes patients vs.
11 (0-65) vs. 3 (0-30) μl (P = 0.03) and higher PWV patients vs. controls at baseline: 9.1 ± 2.2 vs. 7.9 ± 1.4 m/s (P < 0.01), at follow-up: 9.3 ± 2.3 vs. 8.4 ± 1.8 m/s (P = 0.02). Baseline PWV was associated with volumes of all plaque types in crude analysis (P < 0.01) and with low-density noncalcified plaque volume in analysis adjusted for age, sex, diabetes and blood pressure (P = 0.01).
Coronary plaques with unfavorable characteristics are more prevalent in well controlled asymptomatic patients with type 2 diabetes compared with healthy controls and independently associated with arterial stiffness.Clinical trials registration number: NCT02001532.
The association between social relations and health outcomes is well described, but pathways are relatively poorly understood. Inflammation has been suggested as a potential physiological pathway, ...linking social relations to adverse health outcomes. However, previous studies have shown ambiguous results and have for the vast majority been based on studies small in sample size. The aim of the present study is to examine the association between comprehensive measures of structural and positive as well as negative functional aspects of social relations, across four relational domains—partner/spouse, children, other family and friends, and the level of systemic low-grade inflammation in a large population-based middle-aged cohort and to examine variation by gender and socioeconomic position in these associations. The study comprised of 5576 participants in the Copenhagen Aging and Midlife Biobank. The inflammatory biomarkers collected in late midlife included C-reactive protein, Interleukin-6, and TNF-alpha. Multiple linear regression models were implemented to explore associations between social relations and inflammatory measures controlling for gender, age, socioeconomic position, marital status, early major lifeevents and morbidity. Results show weak and ambiguous associations in all analyses. There were no strong indications of interaction with socioeconomic position. Concluding cautiously, men appear to be more vulnerable toward living alone and low contact frequency with family compared to women as regards high level of low-grade inflammation. In conclusion, this large-scale population-based study among middle-aged men and women showed no association between social relations and low-grade inflammation.
•Standard methods for measuring the Atterberg limits (ALs) is tedious and costly.•Hygroscopic water content (wh) is intimately linked to the ALs.•We propose regression models to estimate ALs from wh ...accounting for hysteresis.•Models based on wh were superior to models based on clay, silt, organic carbon or CEC.•Hysteresis had no effect on accuracy of estimating the ALs.
A number of environmental, agronomic and engineering applications require knowledge of the Atterberg limits (liquid limit, LL; plastic limit, PL) and the plasticity index, PI of soils. The tedious and costly nature of standard experimental methods, as well as challenges with measurement repeatability motivated the development of regressions as well as more sophisticated techniques to estimate the Atterberg limits from other properties such as clay content, cation exchange capacity (CEC), and soil specific surface area. The amount of water adsorbed to particle surfaces at relative humidity (RH) < 95% is intimately linked to these soil properties, which suggests that hygroscopic water content (wh) may be a better predictor of the Atterberg limits. The present study (i) proposes regression models that estimate the LL, PL, and PI from wh at different relative humidity values ranging from 10 to 90% and considering water sorption hysteresis, and (ii) compares the performance of the models to other models that comprise clay, silt and organic carbon contents and CEC. For model development, wh was measured by water adsorption and desorption for 168 soil samples that varied widely in terms of geographic origin, clay mineralogy, and soil organic carbon content. The LL and PL were determined with the drop cone penetrometer and rolling device, respectively. Regression models were developed for both sorption directions for nine RH values between 10 and 90%. For 44 independent soil samples, the models estimated LL, PL and PI accurately (e.g., for desorption wh measured at 90% RH, RMSE and r2 values were 6.43% & 0.89; 3.95% & 0.83 and 6.69% & 0.79, respectively). There was no clear effect of sorption direction on the estimation accuracy. The wh determined at higher RH tended to better estimate the Atterberg limits compared to that measured at lower RH. The wh models were superior in estimating LL and PL compared to models that were based on clay content and organic carbon or CEC. For the PI, the models based on CEC performed slightly better than the wh models. Thus, a single measure of wh can provide reliable estimates of the Atterberg limits and PI.
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