North American prairie wetlands are important non-forested land-based carbon storage sites

We evaluated the potential of prairie wetlands in North America as carbon sinks. Agricultural conversion has resulted in the average loss of 10.1 Mg ha(-1) of soil organic carbon on over 16 million ha of wetlands in this region. Wetland restoration has potential to sequester 378 Tg of organic carbon over a 10-year period. Wetlands can sequester over twice the organic carbon as no-till cropland on only about 17% of the total land area in the region. We estimate that wetland restoration has potential to offset 2.4% of the annual fossil CO(2) emission reported for North America in 1990.     

Performance of a buried radioactive high level waste (HLW) glass after 24 years

A radioactive high level waste glass was made in 1980 with Savannah River Site (SRS) Tank 15 waste. This glass was buried in a lysimeter in the SRS burial ground for 24 years. Lysimeter leachate data was available for the first 8 years. The glass was exhumed in 2004. The glass was predicted to be very durable and laboratory tests confirmed this. Scanning electron microscopy of the glass burial surface showed no significant glass alteration consistent with results of other laboratory and field tests. Radionuclide profiling for alpha, beta, and ¹³⁷Cs indicated that Pu was not enriched in the soil while ¹³⁷Cs and ⁹⁰Sr were enriched in the first few centimeters surrounding the glass. Lysimeter leachate data indicated that ⁹⁰Sr and ¹³⁷Cs leaching from the glass was diffusion controlled.     

Unexpected visible‐light‐induced free radical photopolymerization at low light intensity and high viscosity using a titanocene photoinitiator

Most visible‐light photoinitiators are based on electron transfer processes and are comprised of two or more components. These initiators can lose effectiveness in viscous systems because the underlying reactions are diffusion controlled. In this contribution, the visible‐light photoinitiator bis(cyclopentadienyl) bis[2,6‐difluoro‐3‐(1‐pyrryl)phenyl]titanium is characterized for polymerization of viscous systems and low light intensities. This compound absorbs visible light at wavelengths up to 550 nm, and does not rely on diffusion‐controlled electron transfer reactions because it undergoes unimolecular decomposition. In contrast to trends observed for other photoinitiators, the effectiveness of the compound is found to increase markedly with the addition of protonic acids and with increasing system viscosity. For a given concentration of initiator and acid, a remarkably low optimal light intensity for effective polymerization is observed. The origins of these surprising results are discussed in terms of the mechanism of decomposition of the photoinitiator. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Distribution of radiocaesium (137Cs) and radiopotassium (40K) during the cheese production

Distribution of radionuclides depends on various factors, and milk processing into cheese is recommended as one of the significant measures of radiation protection during radioactive contamination of the environment. A total of 16 milk and 16 cheese (soft and hard) samples were examined using HPGe gamma-ray spectrometry to obtain ¹³⁷Cs and ⁴⁰K activity concentrations. The Pearson's correlation coefficients between ¹³⁷Cs and ⁴⁰K were determined (0.73, 0.68, 0.19, −0.23), followed by determination of distribution of ¹³⁷Cs and ⁴⁰K from cow milk to two types of cheeses using food processing retention factors (0.07–0.34). Transfer of ¹³⁷Cs obtained could serve a great purpose for predicting its distribution during cheesemaking.     

Separation and identification of phospholipid peroxidation products

The molecular species in mixtures of phospholipid hydroperoxides are difficult to separate and identify by typical chromatographic and mass spectrometric techniques. As reported by Havrilla and coworkers, silver ion coordination ionspray mass spectrometry (CIS-MS) has proven to be a powerful technique for the identification of mixtures of hydroperoxides. This ionization technique, which involves the formation of Ag⁺ adducts of the hydroperoxides, provides valuable, unambiguous structural information about the hydroperoxides. Herein, we report a method for the analysis and identification of phospholipid hydroperoxides using CIS-MS. We also report an improved method for the separation of phospholipid hydroperoxides by reversed-phase high-performance liquid chromatography (RP-HPLC), which, for the first time, separates some of the hydroperoxide isomers. CIS-MS can be coupled with this RP-HPLC method by the addition of AgBF₄ to the mobile phase or to the HPLC effluent postcolumn, thus allowing powerful HPLC-MS techniques to be used to identify complex mixtures of phospholipid hydroperoxides.     

Structural changes in a commercial lithium-ion battery during electrochemical cycling: An in situ neutron diffraction study

The structural response to electrochemical cycling of the components within a commercial Li-ion battery (LiCoO₂ cathode, graphite anode) is shown through in situ neutron diffraction. Lithuim insertion and extraction is observed in both the cathode and anode. In particular, reversible Li incorporation into both layered and spinel-type LiCoO₂ phases that comprise the cathode is shown and each of these components features several phase transitions attributed to Li content and correlated with the state-of-charge of the battery. At the anode, a constant cell voltage correlates with a stable lithiated graphite phase. Transformation to de-lithiated graphite at the discharged state is characterised by a sharp decrease in both structural cell parameters and cell voltage. In the charged state, a two-phase region exists and is composed of the lithiated graphite phase and about 64% LiC₆. It is postulated that trapping Li in the solid|electrolyte interface layer results in minimal structural changes to the lithiated graphite anode across the constant cell voltage regions of the electrochemical cycle.     

Do older programmers perform as well as young ones? Exploring the intermediate effects of stress and programming experience

Cognition, Technology & Work - There is a widespread perception that older adults are underperformers when compared with younger adults in tasks that involve intense use of technology, such as...     

Genetic Control of Aerogel and Nanofoam Properties,Applied to Ni–MnOx Cathode Design

Aerogels are ultralight porous materials whose matrix structure can be formed by interlinking 880 nm long M13 phage particles. In theory, changing the phage properties would alter the aerogel matrix, but attempting this using the current production system leads to heterogeneous lengths. A phagemid system that yields a narrow length distribution that can be tuned in 0.3 nm increments from 50 to 2500 nm is designed and, independently, the persistence length varies from 14 to 68 nm by mutating the coat protein. A robotic workflow that automates each step from DNA construction to aerogel synthesis is used to build 1200 aerogels. This is applied to compare Ni–MnO_x cathodes built using different matrixes, revealing a pareto-optimal relationship between performance metrics. This work demonstrates the application of genetic engineering to create “tuning knobs” to sweep through material parameter space; in this case, toward creating a physically strong and high-capacity battery.     

Integration of expert knowledge into radial basis function surrogate models

A current application in a collaboration between Chalmers University of Technology and Volvo Group Trucks Technology concerns the global optimization of a complex simulation-based function describing the rolling resistance coefficient (RRC) of a truck tyre. This function is crucial for the optimization of truck tyres selection considered. The need to explicitly describe and optimize this function provided the main motivation for the research presented in this article. Many optimization algorithms for simulation-based optimization problems use sample points to create a computationally simple surrogate model of the objective function. Typically, not all important characteristics of the complex function (as, e.g., non-negativity)—here referred to as expert knowledge—are automatically inherited by the surrogate model. We demonstrate the integration of several types of expert knowledge into a radial basis function interpolation. The methodology is first illustrated on a simple example function and then applied to a function describing the RRC of truck tyres. Our numerical results indicate that expert knowledge can be advantageously incorporated and utilized when creating global approximations of unknown functions from sample points.