Metal salt catalyzed carbenoids the catalysts in trialkyl phosphite copper (I) complex catalyzed decomposition of diazo compounds

Partial rate data, asymmetric induction studies, interrupted experiments and additives studies indicate that copper(I) salt-phosphite complexes are destroyed during the course of reactions with dimethyl diazomalonate (1) and ethyl diazoacetate (2). All evidence is consistent with the copper(I) being oxidized to copper(II) and copper(0) being oxidized by impurities in the olefin which most probably are hydroperoxides. Several new copper(I) salt-phosphite complexes were prepared and examined but none proved as effective for decomposing (1) as copper(II) bis acetylacetonate. The utility of the copper (I) chloride-trimethyl phosphite complex for decomposing (1) is a function of the means of preparation. The three general methods employed furnished samples having superposable i.r. spectra and superposable proton nmr spectra but exhibited varying degrees of line broadening in the P31 nmr. The chiral mixed phosphite ligand 2-phenoxy-5,10,10-trimethyl-1,3-dioxa-2 phosphatricyclo[5,2,15,8,04,9] decane (3) derived from 2,3 bornadiol failed to induce any asymmetric induction in the reaction between (2) and styrene when complexed with copper(I) iodide even though the ligand is chiral at four carbons and phosphorous --Abstract, page iii

Development Of A GIS-Based Watershed Modeling Tool

A GIS-based numerical tool makes watershed and water quality studies easier by bringing key data and analytical components under one GIS roof. Using the familiar Windows environment, analysts can efficiently access international and national environmental information, apply assessment and planning tools, and run a variety of proven, robust point and non-point loading and water quality models. With many of necessary components together in one system, the analysis time is significantly reduced, a greater variety of questions can be answered, and data and management needs can be more efficiently identified. Minimal data requirements and an ease of application are a motivation to develop a new simpler GIS-based watershed modeling tool, particularly for developing countries where there are a lack of temporal and spatial series of data. An objective of this study is to develop such GIS-based numerical tool for assessment of water balance and runoff pollutions caused by point and non-point sources in watershed systems. The core of the model is based on Generalized Watershed Loading Functions with a number of additions and enhancements of runoff, sediment and daily time step calculations. The model is programming in VB.NET, and designed to complement and interoperate with enterprise and full-featured MapWindow open source GIS. It has two components: a runoff component included water balance and nutrient load modules, and a routing component engaged with HEC-RAS model. All components are merging under GIS MapWindow functions as plug-ins. The model has been verified and validated for the Spring Creek watershed (Pennsylvania) and the Tri-An watershed (Vietnam). A comparison between the results obtained from the model and observations, as well as with results from a well-known AVGWLF shows very good agreements. This watershed modeling tool can be served as a multipurpose environmental analysis system in performing watershed- and water-quality-based studies

INVESTIGATION AND RESEARCH OF LANDSLIDE GEOHAZARD IN NORTH-WESTERN PART OF VIETNAM FOR THE SUSTAINABLE DEVELOPMENT OF THE TERRITORY

Joint Research on Environmental Science and Technology for the Eart

Development of a GIS-Based Numerical Model for Watershed and Water Quality Studies

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Trade in wild anurans vectors the urodelan pathogen Batrachochytrium salamandrivorans into Europe

Pathogen pollution has caused dramatic losses of amphibian diversity on a global scale. The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) has been hypothesized to have its origin in Asian urodelan populations, from which it may have been introduced to Europe through the trade in live urodelans. We here show that Bsal is present on wild small-webbed fire-bellied toads (Bombina microdeladigitora) from Vietnam and on representatives of the same species that have recently been imported in Germany. This finding suggests that the installment of measures to mitigate the Bsal threat through the amphibian trade should not be limited to urodeles, but should equally take anurans into account

Numerical Simulation Of Sediment Transport And Bedmorphology Around A Hydraulic Structure On A River

Scour around hydraulic structures is a critical problem in hydraulic engineering. Under prediction of scour depth may lead to costly failures of the structure, while over prediction might result in unnecessary costs. Unfortunately, up-to-date empirical scour prediction formulas are based on laboratory experiments that are not always able to reproduce field conditions due to complicated geometry of rivers and temporal and spatial scales of a physical model. However, computational fluid dynamics (CFD) tools can perform using real field dimensions and operating conditions to predict sediment scour around hydraulic structures. In Korea, after completing the Four Major Rivers Restoration Project, several new weirs have been built across Han, Nakdong, Geum and Yeongsan Rivers. Consequently, sediment deposition and bed erosion around such structures have became a major issue in these four rivers. In this study, an application of an open source CFD software package, the TELEMAC-MASCARET, to simulate sediment transport and bed morphology around Gangjeong weir, which is the largest multipurpose weir built on Nakdong River. A real bathymetry of the river and a geometry of the weir have been implemented into the numerical model. The numerical simulation is carried out with a real hydrograph at the upstream boundary. The bedmorphology obtained from the numerical results has been validated against field observation data, and a maximum of simulated scour depth is compared with the results obtained by empirical formulas of Hoffmans. Agreement between numerical computations, observed data and empirical formulas is judged to be satisfactory on all major comparisons. The outcome of this study does not only point out the locations where deposition and erosion might take place depending on the weir gate operation, but also analyzes the mechanism of formation and evolution of scour holes after the weir gates

TRAPPING CAPABILITY OF MICROLENS 2D ARRAY BY ACOUSTIC MODULATION

In this article, the microlens 2D array created in acoustic-optical medium by the ultrasonic wave modulation is proposed. The expression described the refractive index induced by cross-interference of two perpendicular ultrasonic waves is approximately derived. By simulation, the 2D array of the Gradedrefractive index lenses are appeared in the thin layer with certain strain-acoutstic constant and thickness. The  dependence of focal length and the radius of lens, i.e. its numerical aperture (AN) on thickness and strain constant of layer, and ultrasonic wave intensity are simulated and trapping capability of optical tweezer array is discussed