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61.
62.
Urszula Laska A. Wilk Irena Maliszewska Ludwik Syper 《Journal of surfactants and detergents》2006,9(2):115-124
In the search for environmentally safe surfactants made from inexpensive and renewable sources, the interest has mainly been
focused on new saccharide derivatives. This report describes the synthesis of newly designed nonionic gemini compounds comprising
two reduced sugar headgroups, two alkyl tails, and a 1,1′-ethylenebisurea entity as the spacer linking two amphiphilic glucose-derived
moieties. Thus, the series of N,N′-bis[(3-alkyl-3-deoxy-d-glucitol)ureido]ethylenediamines (bis(CnGT), with Cn=n-C9H9, n-C6-H13, n-C8H17, n-C10H21, or n-C12H25), were prepared using a convenient procedure starting from easily accessible reagents such as d-glucose, n-alkylamines, urea, and ethylenediamine. Their structure and purity were confirmed by means of elemental analysis, electrospray
ionization mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy. Additionally, the present contribution introduces selected properties of these
surfactants, including their thermotropic behavior and biological properties. The presence of two phase transition points,
determined using the differential scanning calorimetry method, indicates liquid-crystalline mesophase formation upon heating.
Furthermore, using the closed-bottle test (OECD Guideline 301D) as well as the biological oxygen demand test for insoluble
substances for biodegradability measurements, it has been concluded that the tested glucose-derived gemini structures achieve
more than 60% biodegradation after 64–75 test days. All tested surfactants were practically nontoxic to bacteria, yeast, and
molds. Owing to their fitting aggregation ability as well as their nontoxicity, they constitute an interesting group of surfactants
for various applications. 相似文献
63.
64.
65.
Solid waste: terminological and long-term environmental risk assessment problems exemplified in a power plant fly ash study 总被引:1,自引:0,他引:1
Legal definitions exert a significant impact on the waste management strategy. Waste that is technically suitable for recovery does not automatically become a raw material if there is no market for it, or its use is not commercially effective and, hence, they should be disposed of. The majority of disposed wastes, including recyclable waste, are not environmentally safe. Waste as a freshly generated anthropogenic material is not geochemically stable. Przezchlebie fly ash surface pond (Upper Silesia, Poland) in the post-closure stage was subject to field validation of the results of laboratory leaching/extraction tests and long-term column experiments on fly ash (FA) leaching behaviour under controlled conditions for environmental risk assessment. The study showed: (i) the possibility of a discontinuous non-linear time delayed increase of pollution potential of disused 'non-hazardous' large-volume waste in the dumping sites to the hazardous level; (ii) inconsistency of the laboratory leaching tests and the actual leaching behaviour of trace metals, particularly when equilibria conditions are dictated by kinetically determined reactions where the test results reflected entirely wash-out (I) and dissolution (II) phases, but did not comprise delayed release (III) phase; and (iii) necessity of life-cycle screening/monitoring of 'non-hazardous' dumping sites for contaminant release as a function of the primary (pH-Eh, ionic strength, ionic composition of solute) and secondary controlling factors (L/S-liquid to solid ratio, water flow conditions) along the vertical profile of an anthropogenic or natural vadose zone. These data are to be used to develop long-term predictive hydrogeochemical models and their field validation, and for providing an early warning and remedial actions with respect to the particular site. The formation of pH (and Eh) as a function of time-dependent (kinetically defined) processes appeared to be a key issue for a correct prediction of the leaching behaviour of waste. The presented case study on FA shows that waste, even those considered non-hazardous and fit for use in a commercially proven applications, should not be treated the same way as a natural raw material. To facilitate waste utilisation and disposal in environmentally safe way and to prioritise its use, reliable environmental risk assessment prediction models and testing procedures, as well as special enforcement strategy and regulations, should be developed with respect to waste and not 'materials.' 相似文献
66.
Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month. Studied filters contained 125 +/- 6 mBq (238)U in equilibrium with (234)U and (230)Th; no (232)Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for (238)U and (234)U and slow dissolution half-times of 173 and 116 d were found for (238)U and (234)U, respectively. No detectable dissolution of (230)Th was found. 相似文献
67.
68.
Effective and selective transformations of propane, butane, cyclopentane, cyclohexane, methylcyclopentane and adamantane under
the action of CO mediated by polyhalomethanes combined with aluminum halides (in the presence of hydride or alkyl (aryl) group
donors or without them) resulting in esters, ketones and aldehydes are summarized.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
69.
Irena Ku
niewska-lach 《加拿大化工杂志》1999,77(3):439-446
A method for the estimation of gas velocity at the flooding point of various packings, based on such fundamental parameters as the porosity and specific surface of the packing itself, has been developed and introduced herein. The proposed relationships can be applied to the computation of rectification and absorption towers alike, within a wide range of physical/chemical properties of the gas and liquid phases. The method presented in this paper should be particularly useful for estimating the flooding-point gas velocity of new packing elements, mostly, because it needs no empirical constants to be determined. 相似文献
70.
Irena Roterman Katarzyna Stapor Krzysztof Gdek Tomasz Gubaa Piotr Nowakowski Piotr Fabian Leszek Konieczny 《International journal of molecular sciences》2021,22(24)
Currently available analyses of amyloid proteins reveal the necessity of the existence of radical structural changes in amyloid transformation processes. The analysis carried out in this paper based on the model called fuzzy oil drop (FOD) and its modified form (FOD-M) allows quantifying the role of the environment, particularly including the aquatic environment. The starting point and basis for the present presentation is the statement about the presence of two fundamentally different methods of organizing polypeptides into ordered conformations—globular proteins and amyloids. The present study shows the source of the differences between these two paths resulting from the specificity of the external force field coming from the environment, including the aquatic and hydrophobic one. The water environment expressed in the fuzzy oil drop model using the 3D Gauss function directs the folding process towards the construction of a micelle-like system with a hydrophobic core in the central part and the exposure of polarity on the surface. The hydrophobicity distribution of membrane proteins has the opposite characteristic: Exposure of hydrophobicity at the surface of the membrane protein with an often polar center (as in the case of ion channels) is expected. The structure of most proteins is influenced by a more or less modified force field generated by water through the appropriate presence of a non-polar (membrane-like) environment. The determination of the proportion of a factor different from polar water enables the assessment of the protein status by indicating factors favoring the structure it represents. 相似文献