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101.
The present paper reports on an observation that dendrite-like polycrystalline structures from evaporating droplets of wheat grain leakages exhibit bilateral symmetry. The exactness of this symmetry, measured by means of fluctuating asymmetry, varies depending on the cultivar and stress factor influence, and seems to correspond to the seed germination rate. In the bodies of plants, animals, and humans, the exactness of bilateral symmetry is known to reflect the environmental conditions of an organism’s growth, its health, and its success in sexual selection. In polycrystalline structures, formed under the same conditions, the symmetry exactness depends on the properties of the crystallizing solution such as the composition and viscosity; however, it has never been associated with sample quality. We hypothesize here that, as in living nature, the exactness of approximate bilateral symmetry might be considered a quality indicator also in crystallographic methods applied to food quality analysis. 相似文献
102.
Kizinievič Olga Voišnienė Violeta Kizinievič Viktor Pundienė Ina 《Journal of Material Cycles and Waste Management》2022,24(1):237-249
Journal of Material Cycles and Waste Management - This paper presents an experimental study on the properties, structure and durability (frost resistance: one-side and all-sides freezing and... 相似文献
103.
104.
Gabriel J. Reyes-Rodríguez Adriana Gioda Olga L. Mayol-Bracero Jeff Collett 《Atmospheric environment (Oxford, England : 1994)》2009,43(27):4171-4177
Chemical characterization to determine the organic and nitrogen fractions was performed on cloud water samples collected in a mountaintop site in Puerto Rico. Cloud water samples showed average concentrations of 1.09 mg L?1 of total organic carbon (TOC), of 0.85 mg L?1 for dissolved organic carbon (DOC) and of and 1.25 mg L?1 for total nitrogen (TN). Concentrations of organic nitrogen (ON) changed with the origin of the air mass. Changes in their concentrations were observed during periods under the influence of African dust (AD). The ON/TN ratios were 0.26 for the clean and 0.35 for the AD periods. Average concentrations of all these species were similar to those found in remote environments with no anthropogenic contribution. In the AD period, for cloud water the concentrations of TOC were 4 times higher and TN were 3 times higher than during periods of clean air masses associated with the trade winds. These results suggest that a significant fraction of TOC and TN in cloud and rainwater is associated to airborne particulate matter present in dust. Functional groups were identified using proton nuclear magnetic resonance (1H NMR) spectroscopy. This characterization led to the conclusion that water-soluble organic compounds in these samples are mainly aliphatic oxygenated compounds, with a small amount of aromatics. The ion chromatography results showed that the ionic species were predominantly of marine origin, for air masses with and without African dust influence, with cloud water concentrations of NO3? and NH4+ much lower than from polluted areas in the US. An increase of such species as SO42?, Cl?, Mg2+, K+ and Ca2+ was seen when air masses originated from northwest Africa. The changes in the chemical composition and physical properties of clouds associated with these different types of aerosol particles could affect on cloud formation and processes. 相似文献
105.
Petro Kapustenko Stanislav Boldyryev Olga Arsenyeva Gennadiy Khavin 《Journal of Cleaner Production》2009,17(10):951-958
This paper originated as a part of a comprehensive research project designed to develop ecologically sustainable, environmentally friendly, resource- and energy-saving industrial process technology for the production of a wide class of phosphorus containing substances. The essential feature of the research was designed for the replacement of tubular heat exchangers with Plate heat exchangers (PHEs) and for the installation of these units in new locations in the processes to optimally improve energy efficiency and to prevent pollution. Despite the severe operating conditions in the production of phosphoric acid PHEs of various designs find the application in these processes. For such a corrosive environment as a phosphoric acid production plant, the Hastelloy G30 alloy is used as the material for the plates and synthetic rubber EPDM is used as the material for inter-plate gaskets. The analysis of the data shows, that using mixed groupings of plates in the unit allows one to obtain optimal solutions. The simulation of barometric mixing condenser recycled water cooling with plate heat exchanger shows the possibility of an application which minimizes the waste water pollution by closing the condenser cooling water circuit. Software was developed for calculations of units working both with liquid and phase changing streams. 相似文献
106.
Pd-Fe nanoparticles stabilized by chitosan derivatives for perchloroethene dechlorination 总被引:3,自引:0,他引:3
Kustov LM Finashina ED Shuvalova EV Tkachenko OP Kirichenko OA 《Environment international》2011,37(6):1044-1052
A series of chitosan-stabilized Pd-NZVI (nano-zero-valent-iron) catalysts for dechlorination with variation in their composition and in the nature of the polymer has been prepared. The synthesis procedures and palladium and chitosan contents were optimized. It was demonstrated by the XPS method that Fe and Pd in Fe-Pd/chitosan samples exist in the metallic state. The positive shift of the binding energy as compared with the bulk metal shows that the iron metal in the surface layers exists as very small nanoparticles. The prepared materials were characterized also by the XAS method. The presence of O and N atoms in the first coordination shell of the central Fe atom in the Fe-Pd/chitosan samples certifies the binding of the Fe metal particles with the chitosan surface via OH and NH(2) groups. The samples are characterized by the high stability of the nanoparticles as compared to unstabilized Pd-NZVI. The materials were tested to evaluate their catalytic activity in the perchloroethene (PCE) dechlorination reaction. Some samples of chitosan-stabilized Pd-NZVI revealed a good performance in PCE degradation as compared to unstabilized Pd-NZVI. 相似文献
107.
Agelos Papaioannou Athina Mavridou Christos Hadjichristodoulou Panagiotis Papastergiou Olga Pappa Eleni Dovriki Ioannis Rigas 《Environmental monitoring and assessment》2010,170(1-4):87-97
Three representative areas (lowland, semi-mountainous, and coastal) have been selected for the collection of drinking water samples, and a total number of 28 physical, chemical, and biological parameters per water sample have been determined and analyzed. The mean values of the physical and chemical parameters were found to be within the limits mentioned in the 98/83/EEC directive. The analysis of biological parameters shows that many of the water samples are inadequate for human consumption because of the presence of bacteria. Cluster analysis (CA) first was used to classify sample sites with similar properties and results in three groups of sites; discriminant analysis (DA) was used to construct the best discriminant functions to confirm the clusters determined by CA and evaluate the spatial variations in water quality. The standard mode discriminant functions, using 17 parameters, yielded classification matrix correctly assigning 96.97% of the cases. In the stepwise mode, the DA produced a classification matrix with 96.36% correct assignments using only ten parameters (EC, Cl???, NO3 ???, HCO3 ???, CO3 ???2, Ca?+?2, Na?+?, Zn, Mn, and Pb). CA and factor analysis (FA) are used to characterize water quality and assist in water quality monitoring planning. CA proved that two major groups of similarity (six subclusters) between 17 physicochemical parameters are formed, and FA extracts six factors that account for 66.478% of the total water quality variation, when all samples’ physicochemical data set is considered. It is noteworthy that the classification scheme obtained by CA is completely confirmed by principal component analysis. 相似文献
108.
Rodrigo Navia Olga Rubilar M Cristina Diez Karl-Heinz Schmidt Gerhard Behrendt Karl E Lorber 《Waste management & research》2007,25(2):119-129
The volcanic soils of southern Chile have demonstrated a high capacity to adsorb environmental pollutants, but for an industrial application, a stable solid material is necessary. The objective of this work was to produce a stable ceramic material through a process involving volcanic soil-polyurethane foam produced with recycled polyethylene terephthalate (PET)-polyols, and further thermal treatment. The selected foam formulation with 35.4% volcanic soil (< 63 microm) seems to be the most suitable for thermal treatment, with temperature steps at 700, 850, 1000 and 1200 degrees C. The porous ceramic material obtained has a stable solid form and an improved chlorophenols adsorption capacity (comparable to natural zeolites) that makes it suitable for advanced wastewater treatment and landfill leachate depuration. 相似文献
109.
Olga V. Taseiko Sergey V. Mikhailuta Anne Pitt Anatoly A. Lezhenin Yuri V. Zakharov 《Atmospheric environment (Oxford, England : 1994)》2009,43(2):245-252
A semi-empirical mathematical model, Urban Street Model (USM), is proposed to efficiently estimate the dispersion of vehicular air pollution in cities. This model describes urban building arrangements by combining building density, building heights and the permeability of building arrangements relative to wind flow. To estimate the level of air pollution in the city of Krasnoyarsk (in Eastern Siberia), the spatial distribution of pollutant concentrations off roadways is calculated using Markov's processes in USM. The USM-predicted numerical results were compared with field measurements and with results obtained from other frequently used models, CALINE-4 and OSPM. USM consistently yielded the best results. OSPM usually overestimated pollutant concentration values. CALINE-4 consistently underestimated these values. For OSPM, the maximum differences were 160% and for CALINE-4 about 400%. Permeability and building density are necessary parameters for accurately modeling urban air pollution and influencing regulatory requirements for building planning. 相似文献
110.