In this work an investigation about the use of the solvents 1,1,2,2‐tetramethoxyethane, also called tetramethoxy glyoxal (TMG), and 1,1,2,2‐tetraethoxyethane also called tetraethoxy glyoxal (TEG), ...which belong to the chemical family of carbonyl derivatives, as electrolyte components for electrical double layer capacitors (EDLCs) and lithium‐ion batteries (LIBs) is reported for the first time. TEG and TMG are commercial solvents displaying a good set of properties, a low toxicity, and a low price. Although for EDLCs the use of these solvents does appear particularly appealing, their use in LIBs is certainly interesting. The preliminary results reported in this study indicate that the performance of lithium iron phosphate electrodes in LIBs using electrolytes based on TEG and TMG is promising in terms of capacity, capacity retention at high C rates, and cycling stability.
Identify this: So far, the search for new electrolytes for energy‐storage devices is based on chemical knowhow and “chemical intuition” of scientists. However, as there is a large number of potential chemicals, the identification of suitable combinations needs to be rationalized. To this end, the use of computational screening for new electrolyte components is proposed as a tool. Using this approach glyoxal‐based solvents have been identified as promising electrolytes.
The insertion of local through-thickness reinforcements into dry fiber preforms by stitching provides a possibility to improve the mechanical performance of polymer–matrix composites perpendicular to ...the laminate plane (out-of-plane). Three-dimensional stress states can be sustained by stitching yarns, leading to increased out-of-plane properties, such as impact resistance and damage tolerance. On the other hand, 3D reinforcements induce dislocations of the in-plane fibers causing fiber waviness and the formation of resin pockets in the stitch vicinity after resin infusion which may reduce the in-plane stiffness and strength properties of the laminate.
In the present paper an experimental study on the influence of varying stitching parameters on in-plane and out-of-plane properties of non-crimp fabric (NCF) carbon fiber/epoxy laminates is presented, namely, shear modulus and strength as well as compression after impact (CAI) strength and mode I energy release rate. The direction of stitching, thread diameter, spacing and pitch length as well as the direction of loading (which is to be interpreted as the direction of the three rail shear loading or the direction of crack propagation in case of mode 1 energy release rate testing) were varied, and their effect on the mechanical properties was evaluated statistically.
The stitching parameters were found to have ambivalent effect on the mechanical properties. Larger thread diameters and increased stitch densities result in enhanced CAI strengths and energy release rates but deteriorate the in-plane properties of the laminate. On the other hand, a good compromise between both effects can be found with a proper selection of the stitching configurations.
Transient absorption (TA) spectroscopy is uniquely suited for understanding kinetic processes initiated by light over vast ranges of time. In combination with white light probes, the recorded ...differential absorption spectra can contain spectroscopic signatures characteristic of specific charge carrier population densities. However, disentangling the often-complex and convoluted spectra is made challenging without robust analysis methods relating the underlying physical mechanisms to the spectral components. In this work, we address the origin of the transient spectra of a model system of emerging solar energy harvesting materials using a monoclinic BiVO4 thin film. Using ground-state optical properties of the semiconductor, we find the main derivative-like spectral response to be related to shifting and broadening of oscillators, rather than specific carrier-related transitions. However, by using the Drude optical model of free carriers, we also identify the transient response related to free-hole density. Importantly, sample heating from the optical pumping, which begins at ∼10 ps and plateaus by ∼200 ps, dominates the overall spectral response at longer times. On the basis of a physical model of the spectral response, a kinetic model is developed that describes the pump power dependence of the free-hole density, as well as the temporal evolution of the spectral changes associated with shifting and broadening of oscillators. First-principles density functional theory calculations are used to rationalize experimental measurements. This comprehensive approach to analyzing and modeling the TA spectra offers a generalizable basis for understanding the complex pump–probe data, reveals thermal heating artifacts that are frequently erroneously assigned to long-lived photocarriers, and offers a path to eliminating ambiguity in analysis of photocarrier dynamics in solid-state systems.
Arrays of graphene solution‐gated field‐effect transistors are fabricated for the detection of electrical activity of electrogenic cells. Cardiomyocyte‐like cells are cultured on the transistor ...arrays and their action potentials are detected by the underlying transistors. The analysis of the recorded cell signals and the electronic noise of the transistors confirm that graphene transistors surpass state‐of‐the‐art devices for bioelectronic applications.
The study tested the hypothesis that certain underused forages and agro-industrial byproducts available in dry areas may positively influence fatty acid (FA) composition and antioxidative properties ...of milk by their contents of residual oil or phenolic compounds or both. Sixty multiparous fat-tailed Awassi ewes were allocated to 6groups in a completely randomized block design. During 50 d, the ewes were group-fed 2.5kg of dry matter/d per ewe 1 of 6 isonitrogenous and isoenergetic diets (forage:concentrate, 0.3:0.7). The test feeds, comprising 30% of the diets, replaced either barley straw lentil straw, olive leaves, and Atriplex (saltbush) leaves, rich in phenolic compounds or electrolytes or conventional concentrate ingredients (olive cake and tomato pomace; ~10% lipids) from the control diet. The diets containing olive cake and tomato pomace were rich in oleic acid (18:1 cis-9; 27% of total dietary FA) and linoleic acid (18:2 cis-9,cis-12; 37%), respectively. Profiles of FA were determined in individual milk samples drawn on d 0 and in wk 1, 3, 5 and 7. Data was analyzed by repeated measurement analysis. No consistent treatment effects on yield and gross nutrient composition of the milk were observed, although some differences occurred. Milk resulting from the Atriplex leaf diet expressed the highest antiradical activity, which was low with control and olive leaves. Feeding the tomato pomace and olive cake diets decreased the proportions of short- and medium-chain FA, whereas oleic acid clearly increased in proportion to total FA. Olive leaves most effectively increased rumenic acid (18:2 cis-9,trans-11) and α-linolenic acid (18:3 cis-9,cis-12,cis-15) in milk fat. This also resulted in the highest α-linolenic acid transfer rate from feed to milk and suggests that olive leaves affect ruminal biohydrogenation at several steps. Several alternative feeds exist with an added value, as they enhance FA with potential health benefits and the stability of the milk with higher antioxidative activity, even though responses to test feeds differed largely. It remains to be investigated whether combinations of these feeds would be complementary in these beneficial effects.
Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel ...magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014) on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.
Based on experimental investigations on structurally stitched non-crimp fabric (NCF) carbon fiber/epoxy laminates under in-plane tension, compression and shear loading
1, a finite element based unit ...cell model was developed to estimate the in-plane strength of NCF laminates taking into consideration the yarn diameter, the stitching pattern and direction as well as the load type. Depending on these parameters, regions with undisturbed and disturbed fiber orientations leading to resin pockets as well as local changes of the fiber volume fraction are taken into account in the model.
The comparison of experimental and numerical results showed that the strength of structurally stitched NCF laminates under in-plane tension, compression or shear loading can be predicted with an acceptable accuracy. The overall mean deviation between simulation and experiment observed was between 8% and 13%.
Summary
Climate change and increased extraction of agricultural residues for bioenergy can adversely affect soil fertility. A more accurate understanding of biomass that remains in or on arable soil ...is necessary to improve results of carbon (C) balances of cropped land. Mechanical and manual harvesting of winter wheat grain and material other than grain (MOG) were carried out at three field stations in Thuringia, Germany, in 2012 and 2013. We compared various methods of harvesting MOG, which resulted in different straw/grain ratios (SGR) and their effect on C balancing. For all experiments, the total biomass yield and SGR were larger for manual than mechanical harvesting. Substantial differences in SGR resulted for the various methods of mechanical MOG recovery. Surprisingly, methods of harvesting without biomass deposition to the soil surface cannot be regarded as more accurate in general than those with intermediate MOG deposition. Using these SGRs to determine the amount of MOG available for the maintenance of soil organic carbon (SOC) resulted in an underestimate of the actual biomass by up to 47%. For stubble heights of 5–15 cm, a mean of 8–22% of MOG remained in the field as stubble. Thus, the method of MOG assessment should be considered for SGR values used to calculate the C input as a model parameter. We demonstrated that SOC is underestimated by up to 24% when the simplified C turnover model CANDY Carbon Balance (CCB) is not parameterized correctly.
Highlights
How do specific straw/grain ratios (SGR) of wheat change modelled carbon accumulation?
Removal of straw from arable soil for energy provision will gain more attention.
Default SGR of the selected carbon model underestimates biomass input to soil by ∼47%.
Consequently carbon accumulation is underestimated by up to 24%.
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