Search results for "MATTER"
showing 10 items of 16762 documents
Structural behaviour differences in low methoxy pectin solutions in the presence of divalent cations (Ca 2+ and Zn 2+ ): a process driven by the bind…
2014
International audience; In this paper, we compare the interactions between low methoxy pectin (LMP) and either Ca2+ or Zn2+ in semi-dilute solutions. Intrinsic viscosity and turbidity measurements reveal that pectin-calcium solutions are more viscous, but yet less turbid, than pectin-zinc ones. To get a molecular understanding on the origin of this rather unexpected behavior, we further performed isothermal titration calorimetry, small angle neutron scattering experiments, as well as molecular dynamics simulations. Our results suggest that calcium cations induce the formation of a more homogeneous network of pectin than zinc cations do. The molecular dynamics simulations indicate that this …
Adsorption of gelatin during electrodeposition of copper and tin-copper alloys from acid sulfate electrolyte
2014
International audience; An acid Cu–Sn deposition bath was developed, and copper and copper–tin coatings were electrodeposited on polycrystalline platinum. The effect of gelatin on copper and copper–tin electrodeposition from acid sulfate solutions has been investigated by a variety of electrochemical methods (voltammetric studies and electrochemical quartz crystal microbalance) as well as by morphologic technique (scanning electron microscopy). The electrochemical results have shown that the overpotential is required when gelatin is added, indicating the presence of interaction between the additive and the coating. From the results of X-ray photoelectron spectroscopy, PM-IRRAS and cyclic vo…
Lipid multilayered particles: the role of chitosan on structure and morphology
2010
Multilayered nanovectors made up from a controlled binary lipid mixture (POPC and DMPS) and trimethyl chitosan (TMC) have been prepared and characterized by light- and small angle neutron scattering. The morphology and the multilayer structure of the particle outer shell has been described in detail. By varying the amount of TMC in the starting solution it is possible to tune the overall surface particle charge as well as its multilamellarity. In this way the drug loading/release properties of the particles can be controlled. Therefore the use of controlled POPC/DMPS mixtures can be a valid alternative to commercial lecithin to obtain nanovectors with specific release properties.
Use of electronic nose to determine defect percentage in oils. Comparison with sensory panel results
2010
Abstract An electronic nose based on an array of 6 metal oxide semiconductor sensors was used, jointly with linear discriminant analysis (LDA) and artificial neural network (ANN) method, to classify oils containing the five typical virgin olive oil (VOO) sensory defects (fusty, mouldy, muddy, rancid and winey). For this purpose, these defects, available as single standards of the International Olive Council, were added to refined sunflower oil. According to the LDA models and the ANN method, the defected samples were correctly classified. On the other hand, the electronic nose data was used to predict the defect percentage added to sunflower oil using multiple linear regression models. All …
Small-angle neutron scattering from lecithin reverse micelles
1996
Abstract We report new results of small-angle neutron scattering from cyclohexane- d 12 /lecithin/water micellar solutions, performed as a function of the water content, w 0 , the temperature, T and the dispersed-phase volume fraction, ф. The data from dilute samples can be interpreted in terms of the existence of giant cylindrical reverse micelles, in good agreement with the current idea of an unlimited micellar growth with ф. In contrast, the appearance of a sharp interference maximum at high concentrations ( ф > 0.15 ) suggests that the current hypothesis of a gel structure interpreted as a random network of entangled micelles can be assumed to be incorrect, and that there must be some c…
Combined use of modified atmosphere packaging and high pressure to extend the shelf-life of raw poultry sausage
2014
International audience; The contribution of modified atmosphere packaging (MAP) in extending the shelf-life of high-pressure treated raw poultry sausages was examined by considering microbial and oxidative stability (TBARs) aspects. Raw poultry sausages packaged under air or modified atmosphere (50% CO2–50% N2) were pressurized at 500 MPa during 5 min at a maximum temperature of 10.5 °C, subsequently allowed to refrigerated storage during 22 days. During storage, samples were tested at time intervals for headspace gas composition, pH, TBARs, Aerobic Mesophilic Counts (AMC) and Lactic Acid Bacteria (LAB) counts. The high pressure treatment could represent an efficient means of extending the …
Factors affecting shoot proliferation and vitrification inDigitalis obscura cultures
1992
Variations of composition and consistency of the culture medium and time of exposure to growth regulators were assayed to optimize normal caulogenic response ofDigitalis obscura hypocotyls cultured in vitro. The effects of the culture conditions on physiologic changes related to vitrification of the regenerated plants were also investigated. Liquid medium increased the bud-forming capacity of the explants but induced buds failed to develop into shoots and showed symptoms of vitrification. On agar-solidified media, maximum multiplication rates were achieved with 0.7% agar. Increasing agar concentration reduced vitrification but lowered the propagation rate. Changes in the strength of the mac…
Humus forms, carbon stock and properties of soil organic matter in forests formed on dry mineral soils in Latvia
2020
Over the last decades, more attention has been paid to carbon accumulation in soil, more recently, to soil humus forms, as they indicate environmental conditions and state of soil organic matter. There is insufficient information on the impact of soil and forest type on the chemical properties of soil, soil organic matter and humus form. Knowledge about the chemical properties of humus is crucial for modelling C and N accumulation and storage in forest soils. On this account, the aim of this study was to characterize soil humus forms, humus chemical properties and C stock and to determine the spatial distribution correlations between soil humus forms in forests formed on dry mineral soils. …
On the discreet spectrum of fractional quantum hydrogen atom in two dimensions
2019
We consider a fractional generalization of two-dimensional (2D) quantum-mechanical Kepler problem corresponding to 2D hydrogen atom. Our main finding is that the solution for discreet spectrum exists only for $\mu>1$ (more specifically $1 < \mu \leq 2$, where $\mu=2$ corresponds to "ordinary" 2D hydrogenic problem), where $\mu$ is the L\'evy index. We show also that in fractional 2D hydrogen atom, the orbital momentum degeneracy is lifted so that its energy starts to depend not only on principal quantum number $n$ but also on orbital $m$. To solve the spectral problem, we pass to the momentum representation, where we apply the variational method. This permits to obtain approximate analytica…
Fabrication of a Silicide Thermoelectric Module Employing Fractional Factorial Design Principles
2021
AbstractThermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While previously optimized Mg2Si0.3Sn0.675Bi0.025 is used as the n-type leg, we employ a fractional factorial design based on the Taguchi methods mapping out a four-dimensional parameter space among Mnx-εMoεSi1.75−δGeδ higher manganese silicide compositions for the p-type material. The module is assembled using a scalable fabrication process, using a Cu metallization layer and a Pb-based soldering paste. The maximum power output density of 53 μW cm–2 is achieved at a hot-side temp…