The ionic liquid SLB-IL111 column, available from Supelco Inc., is a novel fused capillary gas chromatography (GC) column capable of providing enhanced separations of fatty acid methyl esters (FAMEs) ...compared to the highly polar cyanopropyl siloxane columns currently recommended for the separation of cis- and trans isomers of fatty acids (FAs), and marketed as SP-2560 and CP-Sil 88. The SLB-IL111 column was operated isothermal at 168°C, with hydrogen as carrier gas at 1.0mL/min, and the elution profile was characterized using authentic GC standards and synthetic mono-unsaturated fatty acids (MUFAs) and conjugated linoleic acid (CLA) isomers as test mixtures. The SLB-IL111 column provided an improved separation of cis- and trans-18:1 and cis/trans CLA isomers. This is the first direct GC separation of c9,t11- from t7,c9-CLA, and t15-18:1 from c9-18:1, both of which previously required complimentary techniques for their analysis using cyanopropyl siloxane columns. The SLB-IL111 column also provided partial resolution of t13/t14-18:1, c8- from c6/c7-18:1, and for several t,t-CLA isomer pairs. This column also provided elution profiles of the geometric and positional isomers of the 16:1, 20:1 and 18:3 FAMEs that were complementary to those obtained using the cyanopropyl siloxane columns. However, on the SLB-IL111 column the saturated FAs eluted between the cis- and trans MUFAs unlike cyanopropyl siloxane columns that gave a clear separation of most saturated FAs. These differences in elution pattern can be exploited to obtain a more complete analysis of complex lipid mixtures present in ruminant fats.
Sequential density fractionation separated soil particles into “light” predominantly mineral-free organic matter vs. increasingly “heavy” organo-mineral particles in four soils of widely differing ...mineralogy. With increasing particle density C concentration decreased, implying that the soil organic matter (OM) accumulations were thinner. With thinner accumulations we saw evidence for both an increase in ¹⁴C-based mean residence time (MRT) of the OM and a shift from plant to microbial origin.Evidence for the latter included: (1) a decrease in C/N, (2) a decrease in lignin phenols and an increase in their oxidation state, and (3) an increase in δ¹³C and δ¹⁵N. Although bulk-soil OM levels varied substantially across the four soils, trends in OM composition and MRT across the density fractions were similar. In the intermediate density fractions (~1.8-2.6 g cm⁻³), most of the reactive sites available for interaction with organic molecules were provided by aluminosilicate clays, and OM characteristics were consistent with a layered mode of OM accumulation. With increasing density (lower OM loading) within this range, OM showed evidence of an increasingly microbial origin. We hypothesize that this microbially derived OM was young at the time of attachment to the mineral surfaces but that it persisted due to both binding with mineral surfaces and protection beneath layers of younger, less microbially processed C. As a result of these processes, the OM increased in MRT, oxidation state, and degree of microbial processing in the sequentially denser intermediate fractions. Thus mineral surface chemistry is assumed to play little role in determining OM composition in these intermediate fractions. As the separation density was increased beyond ~2.6 g cm⁻³, mineralogy shifted markedly: aluminosilicate clays gave way first to light primary minerals including quartz, then at even higher densities to various Fe-bearing primary minerals. Correspondingly, we observed a marked drop in δ¹⁵N, a weaker decrease in extent of microbial processing of lignin phenols, and some evidence of a rise in C/N ratio. At the same time, however, ¹⁴C-based MRT time continued its increase. The increase in MRT, despite decreases in degree of microbial alteration, suggests that mineral surface composition (especially Fe concentration) plays a strong role in determining OM composition across these two densest fractions.
Fuel cells have gained considerable interest as a means to efficiently convert the energy stored in gases like hydrogen and methane into electricity. Further developing fuel cells in order to reach ...cost, safety and reliability levels at which their widespread use becomes feasible is an essential prerequisite for the potential establishment of a ‘hydrogen economy’. A major factor currently obviating the extensive use of fuel cells is their relatively high costs. At present we estimate these at about 1100 €(2005)/kW for an 80
kW fuel cell system but notice that specific costs vary markedly with fuel cell system power capacity. We analyze past fuel cell cost reductions for both individual manufacturers and the global market. We determine learning curves, with fairly high uncertainty ranges, for three different types of fuel cell technology – AFC, PAFC and PEMFC – each manufactured by a different producer. For PEMFC technology we also calculate a global learning curve, characterised by a learning rate of 21% with an error margin of 4%. Given their respective uncertainties, this global learning rate value is in agreement with those we find for different manufacturers. In contrast to some other new energy technologies, R&D still plays a major role in today’s fuel cell improvement process and hence probably explains a substantial part of our observed cost reductions. The remaining share of these cost reductions derives from learning-by-doing proper. Since learning-by-doing usually involves a learning rate of typically 20%, the residual value for pure learning we find for fuel cells is relatively low. In an ideal scenario for fuel cell technology we estimate a bottom-line for specific (80
kW system) manufacturing costs of 95 €(2005)/kW. Although learning curves observed in the past constitute no guarantee for sustained cost reductions in the future, when we assume global total learning at the pace calculated here as the only cost reduction mechanism, this ultimate cost figure is reached after a large-scale deployment about 10 times doubled with respect to the cumulative installed fuel cell capacity to date.
We study the cross sections for the inclusive production of ψ(2S) and X(3872) hadrons in p p collisions at the LHC at two different center-of-mass energies and compare them with experimental data ...obtained by the ATLAS, CMS, and LHCb Collaborations.
Now that renewable technologies are both technically and commercially mature, the imperfect rational behaviour of investors becomes a critical factor in the future success of the energy transition. ...Here, we take an agent-based approach to model investor decision making in the electricity sector by modelling investors as actors with different (heterogeneous) anticipations of the future. With only a limited set of assumptions, this generic model replicates the dynamics of the liberalised electricity market of the last decades and points out dynamics that are to be expected as the energy transition progresses. Importantly, these dynamics are emergent properties of the evolving electricity system resulting from actor (investor) behaviour. We have experimented with varying carbon price scenarios and find that incorporating heterogeneous investor behaviour results in a large bandwidth of possible transition pathways, and that the depth of renewables penetration is correlated with the variability of their power generation pattern. Furthermore, a counter-intuitive trend was observed, namely that average profits of investors are seen to increase with carbon prices. These results are a vivid and generic illustration that outcome-based policy cannot be solely based on market instruments that rely on perfect rational and perfectly informed agents.
•A model of investor decision making in the electricity sector is presented.•An agent-based approach is used to model bounded rational behaviour of investors.•Dynamics of electricity markets were replicated; carbon price scenarios were explored.•Results show that average profits of investors increase with carbon prices.•Results illustrate that outcome-based policy cannot be solely based on market instruments.
Abstract
A heatwave in June 2021 exposed Pacific Northwest (PNW) snowpack to record temperatures, allowing us to probe seasonal snowpack response to short-term heat extremes. Using high-resolution ...contiguous snowpack and temperature datasets (daily 1 km
2
SNODAS, 4 km
2
PRISM), we examined daily snowmelt in cooler, higher-elevation zones during this event, contrasted with the prior 18 years (2004–2021). We found that multiple early season (spring) heatwaves, concluding with the 2021 heat dome itself, resulted in dramatic early season melt including the most persistent fraction of PNW snowpack. Using longer-term station records (1940–2021), we show that springtime +5 °C daily anomalies were historically rare but since the mid-1990s have doubled in frequency and/or intensity, now potentially affecting typically cool La Niña periods (2021). Collectively, these results indicate that successive heat extremes drive rapid snowmelt, and these extremes may increasingly threaten previously resilient fractions of seasonal snowpack.
Cilia, as motile and sensory organelles, have been implicated in normal development, as well as diseases including cystic kidney disease, hydrocephalus and situs inversus. In kidney epithelia, cilia ...are proposed to be non-motile sensory organelles, while in the mouse node, two cilia populations, motile and non-motile have been proposed to regulate situs. We show that cilia in the zebrafish larval kidney, the spinal cord and Kupffer's vesicle are motile, suggesting that fluid flow is a common feature of each of these organs. Disruption of cilia structure or motility resulted in pronephric cyst formation, hydrocephalus and left-right asymmetry defects. The data show that loss of fluid flow leads to fluid accumulation, which can account for organ distension pathologies in the kidney and brain. In Kupffer's vesicle, loss of flow is associated with loss of left-right patterning, indicating that the `nodal flow' mechanism of generating situs is conserved in non-mammalian vertebrates.
Capacity regions are established for several two-sender, two-receiver channels with partial transmitter cooperation. First, the capacity regions are determined for compound multiple-access channels ...(MACs) with common information and compound MACs with conferencing. Next, two interference channel models are considered: an interference channel with common information (ICCI) and an interference channel with unidirectional cooperation (ICUC) in which the message sent by one of the encoders is known to the other encoder. The capacity regions of both of these channels are determined when there is strong interference, i.e., the interference is such that both receivers can decode all messages with no rate penalty. The resulting capacity regions coincide with the capacity region of the compound MAC with common information.
PDF
