377 research outputs found

    Synthesis and spectral studies of 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxybenzaldehyde(TA)and its Schiff bases with 1,3-diaminopropane(TAAP)and 1,6-diaminohexane(TAAH).Their analytical application for spectrophotometric microdetermination of cobalt(II).

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    Cataloged from PDF version of article.The new azo compound 5-[3-(1,2,4-triazolyl-azo]-2,4-dihydroxy-benzaldehyde (TA) and its Schiff bases with 1,3-diaminopropane (TAAP) and 1,6-diaminohexane (TAAH) have been synthesized. The bands of diagnostic importance in the IR and the main signals in 1 H NMR spectra are assigned. The electronic absorption spectra in pure organic solvents of different polarity and in buffer solutions of varying pH are investigated. The quantitative description of the solvent effect on the electronic absorption spectra is studied and their acid ionization constants are determined. Also, a new simple and sensitive method for the spectrophotometric microdetermination of Co(II) using these compounds (TA, TAAP and TAAH) as new chromogenic reagents is established. The developed method is successfully used for the determination of trace amounts of cobalt in authentic samples and calculation of the distribution ratio of cobalt adsorbed on bentonite and kaolinite clay minerals. 2004 Elsevier Ltd. All rights reserved

    Sorption Studies of Radioiodine on Soils with Special References to Soil Microbial Biomass

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    In batch experiments with two types of soils, chernozem and podzol, radioiodine (125I) showed an initial rapid sorption, followed by a long and slow further increase. Very little sorption (Rd < 1) was detected in clay minerals. Generally, higher. Revalues were observed for the chernozem soil, characterized by a higher amount of organic substance and of soil biomass. The sorption process was predominantly irreversible, the isotherms were linear at low ion concentrations and deviated from linearity starting at 10-5 mmol - ml-1. Sorption ratio was found to increase with increasing volume to mass ratio. The composition of liquid phases (bidistilled water, synthetic soil water, rain water) highly affected iodine sorption. In experiments with KBr solution, the sorption of I “ was found to be strongly preferred to Br”. Incubation of soil samples under varied conditions (decreased or increased soil biomass, 02-concentration, incubation temperature, soil water content and storage conditions) delivered indications for the participation of soil microflora in iodine immobilization. Test with isolated soil bacteria and fungi showed that radioiodine can be incorporated by soil microorganisms under certain conditions only: Considerable uptake of radioiodine was found in washed (NaCl, CaCl2) cells with both bacteria and fungi, but no incorporation was detected into cells incubated with radioiodine in the culture medium. © 1991, Walter de Gruyter. All rights reserved

    Direct visualization of coexisting channels of interaction in CeSb

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    Our understanding of correlated electron systems is vexed by the complexity of their interactions. Heavy fermion compounds are archetypal examples of this physics, leading to exotic properties that weave magnetism, superconductivity and strange metal behavior together. The Kondo semimetal CeSb is an unusual example where different channels of interaction not only coexist, but have coincident physical signatures, leading to decades of debate about the microscopic picture describing the interactions between the f moments and the itinerant electron sea. Using angle-resolved photoemission spectroscopy, we resonantly enhance the response of the Ce f electrons across the magnetic transitions of CeSb and find there are two distinct modes of interaction that are simultaneously active, but on different kinds of carriers. This study reveals how correlated systems can reconcile the coexistence of different modes on interaction-by separating their action in momentum space, they allow their coexistence in real space.11Ysciescopu

    Hierarchical Partial Planarity

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    In this paper we consider graphs whose edges are associated with a degree of {\em importance}, which may depend on the type of connections they represent or on how recently they appeared in the scene, in a streaming setting. The goal is to construct layouts of these graphs in which the readability of an edge is proportional to its importance, that is, more important edges have fewer crossings. We formalize this problem and study the case in which there exist three different degrees of importance. We give a polynomial-time testing algorithm when the graph induced by the two most important sets of edges is biconnected. We also discuss interesting relationships with other constrained-planarity problems.Comment: Conference version appeared in WG201

    Monitoring deformations of Istanbul metro line stations through Sentinel-1 and levelling observations

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    Turkey, as a developing country, is designing and performing massive construction projects around Istanbul. Beginning from the 1960s, rapid urbanization has been taking place due to industrialization, which brings an increase in the population. Yet, construction projects have been accelerated especially during the last decade, and many new projects are scheduled to be completed in a short time. Ground-based observations are generally carried out to monitor the deformations within construction sites, especially through geometric levelling, and GNSS techniques. However, in most cases, these monitoring measurements are only scheduled within the period of the construction process, and ensuing deformations are usually not considered. In addition to these techniques, the space-based interferometric technique can also be used to define the line of sight surface displacements with high accuracy, using the phase difference between image result for synthetic aperture radar images. In particular, Persistent Scatter Interferometry is one of the interferometric methods that are capable of defining the two-dimensional (vertical and horizontal) deformation for the desired epoch with a high temporal resolution. Thus it can be used as a complementary method for monitoring ground deformations, where the measurement is made by ground-based observations. In this study, the deforming areas related to underground metro construction are investigated through significant displacements between 2015 and 2018 of Sentinel-1 space-borne SAR data using the PSI technique. These results are validated by comparison with available levelling data corresponding to the new metro line

    Identification and characterization of 3.8 min 134mI

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    The [gamma]-ray spectra of iodine fractions rapidly separated from the products of slow neutron fission of 235U were studied. A 3.8 +/- 0.2 min species was found and was identified as 134mI from observations of corresponding growth in the intensities of the prominent 847 and 884 keV [gamma]-rays of 53 min 134I. This isomer is analogous to the 2.9 h isomer 134mCs and decays by the sequence 134mI (J[pi] = 8-)(J[pi] = 5+)134I (J[pi] = 4+) by transitions of and 44.4 +/- 0.1 keV(), respectively. For a 316 keV cross-over [gamma]-ray an upper limit of 1 % was obtained, and is near the intensity predicted by M4 systematics. A low-intensity [gamma]-ray of 234.3 +/- 0.5 keV was found This [gamma]-ray is interpreted as evidence for [beta]-decay (2%) of the isomer, possibly to the 0.29 sec 7- isomeric level in 134Xe.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34159/1/0000445.pd

    Device Performance of Emerging Photovoltaic Materials (Version 1)

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    Emerging photovoltaics (PVs) focus on a variety of applications complementing large scale electricity generation. Organic, dye‐sensitized, and some perovskite solar cells are considered in building integration, greenhouses, wearable, and indoor applications, thereby motivating research on flexible, transparent, semitransparent, and multi‐junction PVs. Nevertheless, it can be very time consuming to find or develop an up‐to‐date overview of the state‐of‐the‐art performance for these systems and applications. Two important resources for recording research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley–Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield is included as an analysis parameter among state‐of‐the‐art emerging PVs
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