Search results for " and agriculture"
showing 10 items of 933 documents
Phosphorous doping and drawing effects on the Raman spectroscopic properties of O=P bond in silica-based fiber and preform.
2012
International audience; We report an experimental study of the doping and drawing effects on the Raman activities of phosphorus (P)-doped silica-based optical fiber and its related preform. Our data reveal a high sensitivity level in the full width at half maximum value of the 1330 cm−1 (O = P) Raman band to the P-doping level. Its increase with the P doping level does not clash with an increase in the disorder of the O = P surrendering matrix. In addition, we observe that in the central core region of the sample (higher doping level), the drawing process decreases the relative band amplitude. We tentatively suggest that this phenomenon is due to the change in the first derivate of the bond…
Reduced temperature sensitivity of multicrystalline silicon solar cells with low ingot resistivity
2016
This study presents experimental data on the reduction of temperature sensitivity of multicrystalline silicon solar cells made from low resistivity ingot. The temperature coefficients of solar cells produced from different ingot resistivities are compared, and the advantages of increasing the net doping are explained.
High spatial resolution strain measurements at the surface of duplex stainless steels
2007
International audience; The determination of local strain fields at the surface of materials is of major importance for understanding their reactivity. In the present paper, lithography is used to fabricate grid points at the microscale and to map strain gradients within grains and between grains. This method was applied to duplex stainless steels which exhibit heterogeneous strain distributions under straining conditions. The influence of various parameters (the specimen microstructure, the density of slip bands, the number of systems activated and the grid geometry) on the strain value was discussed.
Vinyl sulfone building blocks in covalently reversible reactions with thiols
2015
In the present study we use quantum-chemical calculations to investigate how the reactivity of vinyl sulfone-based compounds can be modified from an irreversible to a reversible reaction with thiols. Based on the predictions from theory, an array of nine different vinyl sulfones with systematically varying substitution pattern was synthesized and their crystal structures were determined. Subsequent Hirshfeld surface analyses employing the principle of electrostatic complementarity aid the understanding of the crystal packing of the synthesized compounds. Reactivity studies against the nucleophile 2-phenylethanethiol mirror the properties predicted by the quantum-chemical computations in sol…
Hybrid GMP–polyamine hydrogels as new biocompatible materials for drug encapsulation
2020
Here we present the preparation and characterization of new biocompatible materials for drug encapsulation. These new gels are based on positively charged [1+1] 1H-pyrazole-based azamacrocycles which minimise the electrostatic repulsions between the negatively charged GMP molecules. Rheological measurements confirm the electroneutral hydrogel structure as the most stable for all the GMP-polyamine systems. Nuclear magnetic resonance (NMR) was employed to investigate the kinetics of the hydrogel formation and cryo-scanning electron microscopy (cryo-SEM) was used to obtain information about the hydrogel morphology, which exhibited a non-homogeneous structure with a high degree of cross-linking…
Applicability of a single‐use bioreactor compared to a glass bioreactor for the fermentation of filamentous fungi and evaluation of the reproducibili…
2021
Abstract The implementation of single‐use technologies offers several major advantages, e.g. prevention of cross‐contamination, especially when spore‐forming microorganisms are present. This study investigated the application of a single‐use bioreactor in batch fermentation of filamentous fungus Penicillium sp. (IBWF 040‐09) from the Institute of Biotechnology and Drug Research (IBWF), which is capable of intracellular production of a protease inhibitor against parasitic proteases as a secondary metabolite. Several modifications to the SU bioreactor were suggested in this study to allow the fermentation in which the fungus forms pellets. Simultaneously, fermentations in conventional glass b…
Role of lignin and sodium carbonate on the swelling behavior of black liquor droplets during combustion
2018
AbstractA partial removal of lignin from black liquor (BL) by carbonation and lignin precipitation was studied. In lignin-lean BL droplets during combustion in a laboratory furnace at 800°C in stagnant air, the maximum swelling was decreased. This observation was interpreted as showing that the lignin content decrement is due mainly to removal of higher molar mass (HMM) lignin and that the Na2CO3content of the BL is increased. Stepwise precipitation experiments with industrial softwood and hardwood kraft BLs by carbonation (resulting in pH decrement from 13 to 9) indicated that a fraction of HMM lignin (MM >10 kDa) with a higher amount of carbohydrates precipitated more prominently and e…
Novel Wood Resistance Measurement Method Reducing the Initial Transient Instabilities Arising in DC Methods Due to Polarization Effects
2019
A novel method for measuring the electrical resistance in wood is presented. It is based on applying an Alternating Current (AC) to two electrodes rammed into the wood. The method reduces the transient time for value stabilization. In case of Direct Current (DC) resistance measurement methods, typically used in wood measurement, an initial transient exists, invalidating the measured value during an initial transient period. This measurement method uses an electronic circuit based on a relaxation oscillator where the wood automatically sets the oscillation frequency depending on its electrical resistance. Compared to other AC methods, this circuit greatly simplifies the measurement process, …
Mechanical properties of natural fiber composites produced using dynamic sheet former
2018
Composites formed from wood fibers and man-made cellulosic fibers in PLA (polylactic acid) matrix, manufactured using sheet forming technique and hot pressing, are studied. The composites have very low density (due to high porosity) and rather good elastic modulus and tensile strength. As expected, these properties for the four types of wood fiber composites studied here improve with increasing weight fraction of fibers, even if porosity is also increasing. On the contrary, for man-made cellulosic fiber composites with circular fiber cross-section, the increasing fiber weight fraction (accompanied by increasing void content) has detrimental effect on stiffness and strength. The differences …
The effects of different combinations of fixed and moving bed bioreactors on rainbow trout (Oncorhynchus mykiss) growth and health, water quality and…
2019
Abstract The effect of bioreactor design on nitrification efficiency has been well studied, but less is known about the overall impacts on water quality. Besides nitrification, submerged fixed bed bioreactors (FBBR) trap fine solid particles, whereas moving bed bioreactors (MBBR) grind solids, possibly increasing solids and particle accumulation in the system. In this experiment, the effects of different combinations of fixed bed and moving bed bioreactors on water quality, solids removal, particle size distribution, fish health based on histopathological changes and nitrification efficiency were studied in laboratory scale recirculating aquaculture systems (RAS) with rainbow trout (Oncorhy…