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排序方式: 共有272条查询结果,搜索用时 31 毫秒
141.
Remo Merijs‐Meri Janis Zicans Tatjana Ivanova Ivan Bochkov Madara Varkale Piotr Franciszczak Andrzej K. Bledzki Paulius Pavelas Danilovas Janis Gravitis Kristaps Rubenis Valentina Stepanova Janis Locs 《Polymer Engineering and Science》2019,59(12):2467-2473
Oat and spelt husks (OH and SH, respectively) lignocellulosic biomass derived fillers have been compared with commercial wood flour (WF) in respects to their morphology, chemical composition, bulk density, aspect ratio, and thermal stability. OH and SH have been obtained by both mechanical milling and steam explosion auto‐hydrolysis treatment at various processing conditions. Reinforcement efficiency of OH and SH derived lignocellulosic biomass fillers on the flexural properties of maleic acid‐grafted polypropylene (PPgMA) compatibilized polypropylene (PP) composites is compared with that of WF. The compatibilized PP composites have been manufactured by melt compounding. Flexural test specimens of the compatibilized PP composites have been manufactured by injection molding. It has been demonstrated that both the husks derived lignocellulose fillers can be used to improve flexural modulus and maximal flexural strength of PP, although its modifying effect is somewhat smaller in comparison to WF reinforcement, most probably due to higher cellulose content of the latter. Husks derived lignocellulose filler‐reinforced PP composites, however, demonstrate increased flexibility in comparison to WF‐filled systems. POLYM. ENG. SCI., 59:2467–2473, 2019. © 2019 Society of Plastics Engineers 相似文献
142.
van den Tempel T Gundersen JK Nielsen MS 《International journal of food microbiology》2002,75(1-2):157-161
Profiles of oxygen in Danablu cheese at the age of 1-19 weeks were measured by using an oxygen microsensor. In a cheese ripened for 1 week, the percentage oxygen saturation decreased to 70% at 0.25-mm depth and further to 50% at 4-mm depth. In a more extended determination of oxygen profiles, the spatial and temporal development in the oxygen level was investigated at 5-mm resolution at the center and 5 mm from the edge of the cylindrical cheeses at a depth of 45 mm. Average oxygen saturation decreased from 63% to 0.1% at the centre and from 69% to 0.1% at the edge in cheeses from 1 to 19 weeks. In the cheeses ripened for more than 3 weeks, oxygen was not detectable, except for a surface layer of 0.25 mm and in apparent small air pockets within the cheese containing about 3% saturated oxygen. 相似文献
143.
Aleksandra A. Perić-grujić Tatjana M. Vasiljević Olivera M. Nešković Miomir V. Veljković Zoran V. Laušević Mila D. Laušević 《Bulletin of Materials Science》2006,29(5):467-473
The effects of boron and phosphorus incorporation in phenolic resin precursor to the oxidation resistance of glassy carbon
have been studied. In order to reveal the nature and composition of the oxygen complexes formed at the surface of doped glassy
carbon, under controlled atmosphere, the surface of the samples was cleaned under vacuum up to 1273 K. Specific functional
groups, subsequently formed under dry CO2 or O2 atmosphere on the surface of boron-doped and phosphorus-doped glassy carbon samples, were examined using the temperature-programmed
desorption method combined with mass spectrometric analysis. Characterization of surface properties of undoped and doped samples
has shown that in the presence of either boron or phosphorus heteroatoms, a lower amount of oxygen complexes formed after
CO2 exposure, while, typically, higher amount of oxygen complexes formed after O2 exposure. It has been concluded that the surface of undoped glassy carbon has a greater affinity towards CO2, while in the presence of either boron or phosphorus heteroatoms, the glassy carbon surface affinity becomes greater towards
O2, under experimental conditions. 相似文献
144.
Wastewater from a tannery was investigated using chemical-specific analyses and assessment of the acute toxicity of the whole effluent over a 2-year period. The wastewater samples were overloaded with organic and inorganic compounds, and measured concentrations of the chemical parameters as well as dilution factors estimating acute toxicity, frequently exceeded the permissible limits for the discharge of wastewater from a tannery into the receiving stream. In the later part of the monitoring programme, the toxicity of the samples was significantly increased in comparison to the previous samples. The agent for hide disinfection was assumed to be the reason for the increased toxicity of the wastewater samples, and the extremely high acute and chronic toxicity of the agent to bacteria, algae, daphnids, and fish confirmed this suspicion. The most sensitive species was Daphnia magna; the 48 h EC50 was 0.70 x 10(-5)v/v% and the 21d IC25 was 0.40 x 10(-6)v/v% of the agent. After withdrawal of this highly toxic agent for hide disinfection from the technological process in the tannery, the toxicity of the wastewater declined to the previous level. 相似文献
145.
Majda?Sfiligoj SmoleEmail author Zdenka?Per?in Tatjana?Kre?e Karin?Stana Kleinschek Volker?Ribitsch Susanne?Neumayer 《Materials Research Innovations》2003,7(5):275-282
Regenerated cellulose fibres have had an important role to play in the man-made fibre field. The very special characteristics of different types of regenerated cellulose fibres, e.g. mechanical properties, sorption characteristics, and aesthetics were conditioned by the differences in their fine structure due to fibre formation processes. Additionally, the finishing processes could influence the fibre structure. A study was done of the crystalline structures of a solvent-spun cellulose fibre type (Lenzing Lyocell), made according to the NMMO process, and two conventional cellulosic fibre types, made by the viscose process (Lenzing Viscose and Lenzing Modal). The fibres were pre-treated (bleached and slack mercerised) and structural changes were followed by wide angle and small angle x-ray scattering (WAXS and SAXS), respectively. The periodical structure, determined by long spacing, was nearly the same in all the different types of fibres. A slight increase was observed after the treatment of viscose and modal fibres, but an unpronounced fall of a long period accompanied the pre-treatment of lyocell fibres. Some changes in crystallinity and crystalline orientation occurred due to the treatment conditions. The structural changes were correlated to the iodinesorption and mechanical properties. 相似文献
146.
Scheduling program tasks on processors is at the core of the efficient use of multiprocessor systems. Most task-scheduling problems are known to be NP-Hard and, thus, heuristics are the method of choice in all but the simplest cases. The utilization of acknowledged sets of benchmark-problem instances is essential for the correct comparison and analysis of heuristics. Yet, such sets are not available for several important classes of scheduling problems, including multiprocessor scheduling problem with communication delays (MSPCD) where one is interested in scheduling dependent tasks onto homogeneous multiprocessor systems, with processors connected in an arbitrary way, while explicitly accounting for the time required to transfer data between tasks allocated to different processors. We propose test-problem instances for the MSPCD that are representative in terms of number of processors, type of multiprocessor architecture, number of tasks to be scheduled, and task graph characteristics (task execution times, communication costs, and density of dependencies between tasks). Moreover, we define our task-graph generators in a way appropriate to ensure that the corresponding problem instances obey the theoretical principles recently proposed in the literature. 相似文献
147.
The electrokinetic properties of macroscopic solids can describe both the surface modifications as well as the interaction abilities during processing. Normally the zeta potential (ζ) is measured and can be used to develop, optimise and control the manufacturing process. The zeta potential of natural and regenerated cellulose fibres changes noticeably during the pre‐treatment and finishing process and it is important for the quality of the final product (whiteness, colour, hydrophilicity). The pre‐treatment of cellulose fibres improves the accessibility of dissociable groups. Further improvement of hydrophilicity (mercerisation) causes a pronounced increase in the surface charge density and a reduction in the degree of crystallinity and structural modifications. The progress of the chemical as well as the enzymatic treatment correlates with ζ. These data correlate very well with the results obtained using tensiometry, water retention, and water vapour and iodine adsorption. The changes in crystallinity index and the accessibility for low molecular components are well described by the latter methods. 相似文献
148.
Spartak S. Khutsishvili Alla I. Perfileva Olga A. Nozhkina Tatjana V. Ganenko Konstantin V. Krutovsky 《International journal of molecular sciences》2021,22(21)
New promising manganese-containing nanobiocomposites (NCs) based on natural polysaccharides, arabinogalactan (AG), arabinogalactan sulfate (AGS), and κ-carrageenan (κ-CG) were studied to develop novel multi-purpose trophic low-dose organomineral fertilizers. The general toxicological effects of manganese (Mn) on the vegetation of potatoes (Solanum tuberosum L.) was evaluated in this study. The essential physicochemical properties of this trace element in plant tissues, such as its elemental analysis and its spectroscopic parameters in electron paramagnetic resonance (EPR), were determined. Potato plants grown in an NC-containing medium demonstrated better biometric parameters than in the control medium, and no Mn accumulated in plant tissues. In addition, the synthesized NCs demonstrated a pronounced antibacterial effect against the phytopathogenic bacterium Clavibacter sepedonicus (Cms) and were proved to be safe for natural soil microflora. 相似文献
149.
Conversion of methane in high yields to C4+ nonaromatic hydrocarbons was demonstrated in a recycle system. The principal components of the recycle system included an
oxidative coupling reactor with a Mn/Na2WO4/SiO2 catalyst at 800°C for conversion of methane to ethylene, and a reactor with an H-ZSM-5 zeolite at 275°C for subsequent conversion
of ethylene to higher hydrocarbons. Total yields of C4+ products were in the range of 60–80%, and yields of C4+ nonaromatic hydrocarbons were in the range of 50–60%.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
150.
Ivan M. Savic Ivana Lj. Nikolic Ivana M. Savic-Gajic Tatjana D. Kundakovic 《分离科学与技术》2019,54(5):837-846
The aim of study was to model and optimize the extraction of polyphenols and flavonoids with expressed antioxidant activity from chickpea seeds using a central composite design. The optimal extraction conditions were the extraction time of 145.5 min, ethanol concentration of 83.7% and liquid-to-solid ratio of 24.9 (expressed as cm3 per g). The content of total polyphenol and flavonoid was 2.75 g gallic acid equivalent per kilogram of the dried extract and 0.147 g rutin equivalent per kilogram of the dried extract, respectively. Using 2,2-diphenyl-1-picrylhydrazyl assay, it was found that the optimal extract had the IC50 of 1.55 mg cm?3. 相似文献