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721.
Jakub Zdarta Marcin Wysokowski Ma?gorzata Norman Agnieszka Ko?odziejczak-Radzimska Dariusz Moszyński Hieronim Maciejewski Hermann Ehrlich Teofil Jesionowski 《International journal of molecular sciences》2016,17(9)
A new method is proposed for the production of a novel chitin-polyhedral oligomeric silsesquioxanes (POSS) enzyme support. Analysis by such techniques as X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the effective functionalization of the chitin surface. The resulting hybrid carriers were used in the process of immobilization of the lipase type b from Candida antarctica (CALB). Fourier transform infrared spectroscopy (FTIR) confirmed the effective immobilization of the enzyme. The tests of the catalytic activity showed that the resulting support-biocatalyst systems remain hydrolytically active (retention of the hydrolytic activity up to 87% for the chitin + Methacryl POSS® cage mixture (MPOSS) + CALB after 24 h of the immobilization), as well as represents good thermal and operational stability, and retain over 80% of its activity in a wide range of temperatures (30–60 °C) and pH (6–9). Chitin-POSS-lipase systems were used in the transesterification processes of rapeseed oil at various reaction conditions. Produced systems allowed the total conversion of the oil to fatty acid methyl esters (FAME) and glycerol after 24 h of the process at pH 10 and a temperature 40 °C, while the Methacryl POSS® cage mixture (MPOSS) was used as a chitin-modifying agent. 相似文献
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Maciej Marcin Michałek 《Journal of Intelligent and Robotic Systems》2014,75(1):29-52
Maneuvers performed with tractor-trailers vehicles (N-trailers) belong to the most demanding motion control tasks in the transportation practice. Very frequent maneuvers concern the lining-up process of a vehicle chain, usually as a preliminary stage which prepares the system to subsequent parking/docking maneuvers. The most common lining-up control approach results from utilization of the open-loop asymptotic stability of N-trailer joint-angle dynamics in the forward motion. However, in case of long trailers this approach appears very inefficient especially if the available motion space is substantially limited. By using the triangular forms of joint-angle dynamics the problem of lining-up control for N-trailers is analyzed in the paper by considering two alternative strategies: active lining-up (feedback control) and passive lining-up (open-loop control). The two strategies are compared in the context of their practical effectiveness, and how the effectiveness depends on kinematic parameters of the trailers and their interconnections. It is revealed why the active strategy can be much more efficient in most practical cases. Theoretical considerations are validated by results of numerical simulations and experiments conducted with a laboratory-scale three-trailer robotic vehicle. 相似文献
724.
Witold Węglewski Michał Basista Marcin Chmielewski Katarzyna Pietrzak 《Composites Part B》2012,43(2):255-264
Thermal stresses induced during the cooling of Cr–Al2O3 (MMC) processed by sintering are modeled numerically using the FEA. The composite microstructure is modeled as (i) random distribution of ceramic particles (voxels) in the metal matrix, and (ii) using micro-CT scans of the real microstructure transformed into a FE mesh. Numerical simulations of the thermal residual stresses are compared with the test data measured by X-ray diffraction. A simple numerical model is then proposed to predict the overall elastic properties of the composite with account of the porosity and damage induced by the thermal stresses. Comparison of the model predictions with the measured data for Young’s modulus is presented. 相似文献
725.
Wojciech Marcin Budzianowski 《Energy》2011,36(11):6318-6325
The article analyses to what extent ‘negative net CO2 emissions’ from decarbonised biogas-to-electricity can contribute to solving Poland’s carbon capture and sequestration dilemmas. From the criteria-based evaluation of low-carbon power technologies it is found, that biogas-to-electricity is among technologies having increasing production potential in Poland. Therefore, in future biogas will be able to contribute to solving Poland’s CCS dilemmas, because it offers carbon-neutral electricity. Moreover, by applying CCS into biogas-to-electricity the ‘negative net CO2 emissions’ can be achieved. The article examines three biogas-to-electricity technologies involving CO2 capture, i.e. biogas-to-biomethane, biogas-to-CHP and biogas-to-electricity via the ORFC cycle. It is emphasised that the ORFC cycle offers low-cost CO2 separation from a CO2-H2 mixture, low O2-intensity, and the opportunities for advanced mass and energy integration of involved processes. Besides, energy conversion calculations show that the ORFC cycle can offer comparable cycle efficiency with air- and oxy-combustion combined cycles. In regard to the design of biogas-based energy systems it is recommended to include (i) distributed production of biogas in order to avoid costs of long-distance transportation of high-moisture content biomass and (ii) centralised large-scale decarbonised biogas-to-electricity power plants since costs of pipeline transportation of gases are low but large-scale plants could benefit from increased energy and CCS efficiencies. 相似文献
726.
Maintaining postharvest quality of cold stored ‘Hass’ avocados by altering the fatty acids content and composition with the use of natural volatile compounds – methyl jasmonate and methyl salicylate
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Joanna Kolmas Marzena Kuras Ewa Oledzka Marcin Sobczak 《International journal of molecular sciences》2015,16(5):11452-11464
The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA300) and selenate (HA300-1.2SeO4) or selenite (HA300-1.2SeO3) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA300-1.2SeO4 and HA300-1.2SeO3, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. 31P and 1H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA300-1.2SeO3. 1H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. 1H→77Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface. 相似文献