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The isomerization equilibrium existing between the different forms of rhodamine B (RhB) is analyzed to study the aggregation of carbosiloxane dendrimers (CSiO-D) taking place in a dilute solution. The RhB isomerization is shown to tremendously increase at the critical aggregation concentration of these dendrimers.

Bisphenol A (BPA), a widely used petrochemical compound, has become an emerging global environmental management challenge because its leakage is associated with potential environmental and human health impacts. Until now, available BPA statistics have been limited to the products that directly use BPA. In this study, we delineate direct and indirect BPA flows for the 2012 Chinese economy. We find that construction, production of educational and recreational products, and automobile manufacturing are the most BPA-intensive sectors in terms of total BPA flows (300, 157, and 130 Gg total BPA flows, respectively). The public management and health sectors, however, incur significant indirect BPA flows, defined as embedded and inter-sectoral BPA placed into use, even though direct BPA use by these sectors is limited. By revealing the currently overlooked indirect BPA flows, this study reveals data gaps that are highly relevant to improving the accuracy of estimated BPA flows and losses. The method used herein is transferrable to other emerging and environmentally relevant materials, thereby providing the holistic understanding needed for cities, regions, or nations to design effective policy interventions. [ABSTRACT FROM AUTHOR]

Metals are used in numerous products and are sourced via increasingly global and complex supply chains. Monetary input--output tables (MIOT) and network analysis can be applied to intersectoral supply chains and used to analyze structural aspects. We first provide a concise review of the literature related to network analysis applied to MIOTs. On the basis of a physical input--output table (PIOT) table of aluminum in the United States economy in 2007, we identify key sectors and discuss the overall topology of the aluminum network using tools of network analysis. Sectors highly dependent on metal product inputs or sales are identified using weighted degree centrality and their hierarchical organization is explored via clustering. Betweenness centrality and random walk centrality (page rank) are explored as means to identify network bottlenecks and relative sector importance. Aluminum, even though dominated by uses in the automobile, beverage and containers, and construction industries, finds application in a wide range of sectors. Motor vehicle parts manufacturing relies on a large number of upstream and downstream suppliers to function. We conclude by analyzing structural aspects of a subnetwork for automobile manufacturing and discuss how the use of network analysis relates to current criticality analyses of metal and mineral resources. [ABSTRACT FROM AUTHOR]

Based on the combination of the U.S. economic input-output table and the stocks and flows framework for characterizing anthropogenic metal cycles, this study presents a methodology for building material flow networks of bulk metals in the U.S. economy and applies it to aluminum. The results, which we term the Input-Output Material Flow Networks (IO-MFNs), achieve a complete picture of aluminum flow in the entire U.S. economy and for any chosen industrial sector (illustrated for the Automobile Manufacturing sector). The results are compared with information from our former study on U.S. aluminum stocks and flows to demonstrate the robustness and value of this new methodology. We find that the IO-MFN approach has the following advantages: (1) it helps to uncover the network of material flows in the manufacturing stage in the life cycle of metals; (2) it provides a method that may be less time-consuming but more complete and accurate in estimating new scrap generation, process loss, domestic final demand, and trade of final products of metals, than existing material flow analysis approaches; and, most importantly, (3) it enables the analysis of the material flows of metals in the U.S. economy from a network perspective, rather than merely that of a life cycle chain. [ABSTRACT FROM AUTHOR]

Determinations of in-use material stocks are useful for exploring past patterns and future scenarios of materials use, for estimating end-of-life flows of materials, and thereby for guiding policies on recycling and sustainable management of materials. This is especially true when those determinations are conducted for individual products or product groups such as "automobiles" rather than general (and sometimes nebulous) sectors such as "transportation". We propose four alternatives to the existing top-down and bottom-up methods for estimating in-use material stocks, with the choice depending on the focus of the study and on the available data. We illustrate with aluminum use in automobiles the robustness of and consistencies and differences among these four alternatives and demonstrate that a suitable combination of the four methods permits estimation of the in-use stock of a material contained in all products employing that material, or in-use stocks of different materials contained in a particular product. Therefore, we anticipate the estimation in the future of in-use stocks for many materials in many products or product groups, for many regions, and for longer time periods, by taking advantage of methodologies that fully employ the detailed data sets now becoming available. [ABSTRACT FROM AUTHOR]

A cycle is the quantitative characterization of the flows of a specific material into, within, and from a given system. An anthropogenic elemental cycle can be static (for a point in time) or dynamic (over a time interval). The about 350 publications collected for this review contain a total of 1074 individual cycle determinations, 989 static and 85 dynamic, for 59 elements; more than 90% of the publications have appeared since 2000. The cycles are of varying quality and completeness, with about 80% at country- or territory-level, addressing 45 elements, and 5% at global-level, addressing 30 elements. Despite their limitations, cycles have often been successful in revealing otherwise unknown information. Most of the elements for which no cycles exist are radioactively unstable or are used rarely and in small amounts. For a variety of reasons, the anthropogenic cycles of only perhaps a dozen elements are well characterized. For all the others, with cycles limited or nonexistent, our knowledge of types of uses, lifetimes in those uses, international trade, losses to the environment, and rates of recycling is quite limited, thereby making attempts to evaluate resource sustainability particularly problematic. [ABSTRACT FROM AUTHOR]

A Cu2+specific colorimetric sensor 1, which is stabilized by an intramolecular hydrogen bonding, was designed and developed. The color of 1changes from purple to blue on addition of 1.0 μM Cu2 aqueous buffer solution, which can be detected by the naked eye. The analytical detection limit for Cu2 the naked eye is as low as 1.0 μM. The stoichiometry for 1and Cu2 complex is 2:1 in aqueous solution. [ABSTRACT FROM AUTHOR]