Application of coagulation by sweep for removal of metals in natural water used in dairy cattle

Use contaminated water to wash the teats of animals and tools, among others, is due to the presence of potential pathogens and pesticide residues, antibiotics and metalsin raw milk. Washing with water of excellent quality, premilkingis a key to reduce the contamination of milk and prevent these compounds are adsorbed on the skin of theudder and then migrate to milk gun. Aluminum sulfate, ferricchloride and chitosan for the removal of turbidity, colorand TOC in natural waters used in the daily activities of a dairy herd, plus the removal of metals such as copper, cobalt and zinc was assessed found was used frequently in natural waters in some regions of Colombia, in this case using the sweep coagulation to improve the removal efficiency. Ferric chloride was the most effective coagulant for conventional removal of turbidity, color and TOC removal percentages greater than 70% and a coagulant dose of 60 mg/L, while for the optimum metal removal doses were 235 mg/L and 500 mg/L aluminum sulfate, and 300 mg/Land 510 mg/L of ferric chloride, achieving removal percentages above 80 % for most metals. Chitosan did not showlarge removal efficiencies compared to other coagulants

Extended Hubbard Model: A Cluster Effective-medium Approach

We present a cluster effective-medium approach to the extended Hubbard model, for the zero-temperature, half-filled-band paramagnetic phase. We recover the known limits and comment on the broadening corrections to the model, and find a first-order metal-insulator transition, resulting from both the cluster nature of the method and the correlated hopping term. © 1993 The American Physical Society.4719124451245

Superconductivity And Antiferromagnetism For An Extended Hubbard Hamiltonian: Role Of Correlated Hopping In A Single-band Model

An extended Hubbard model for a single band, including Coulomb repulsion and correlated hopping between nearest neighbors, is studied using a generalized mean-field approach. Antiferromagnetism and superconductivity are probed for arbitrary occupation number, near and away from half filling. Binding of pairs in the superconducting state of this purely repulsive model is mediated by the correlated hopping in the form of a covalent-bond configuration, with partial intrasite and intersite pairings. A region of coexistence is conjectured, the superconductivity being suppressed by the saturation of the staggered magnetic moment. Singlet superconducting nonmagnetic states are obtained for the almost-empty- or full-band cases. On the other hand, antiferromagnetism induces mixed s- and p-type superconductivities in the neighborhood of half filling. © 1993 The American Physical Society.4721144171442

Optioneering analysis for connecting Dogger Bank offshore wind farms to the GB electricity network

This paper outlines possibilities for connecting 2.4 GW of power from two separate wind farms at Dogger Bank in the North Sea to the GB transmission system in Great Britain. Three options based on HVDC with Voltage Source Converters (VSC HVDC) are investigated: two separate point-to-point connections, a four-terminal multi-terminal network and a four-terminal network with the addition of an AC auxiliary cable between the two wind farms. Each option is investigated in terms of investment cost, controllability and reliability against expected fault scenarios. The paper concludes that a VSC-HVDC point-to-point connection is the cheapest option in terms of capital cost and has the additional advantage that it uses technology that is commercially available. However, while multi-terminal connections are more expensive to build it is found that they can offer significant advantages over point to point systems in terms of security of supply and so could offer better value for money overall. A multi-terminal option with an auxiliary AC connection between wind farms is found to be lower cost than a full multi-terminal DC grid option although the latter network would offer ability to operate at greater connection distances between substations

Development of a stress-induced martensitic transformation criterion for a Cu-Al-Be polycrystalline shape memory alloy undergoing uniaxial tension

This study presents a criterion for predicting the martensitic variants (MVs) that appear during the stress-induced martensitic transformation (SIMT) in a polycrystalline sample of Cu 11.5% wt. Al 0.5% wt. Be under simple tension. Our criterion is based on crystallographic parameters, such as the crystal orientation and Schmid factor (SF). The displacement vector fields (DVFs) were obtained in the observation system by a mathematical model and were used to distort the boundary of a set of grains. From the DVF, the strain tensor for each grain was obtained, and the strain ratio (SR) in the observation system was calculated. Electron backscattering diffraction (EBSD) measurements were performed to determine the crystal orientation of the grains. The inverse SF was used to determine the in-plane stress transformation diagrams (STDs) for each studied grain. The combination of a balance criterion (BC) and STD provided a criterion that allowed us to predict the possible order of stress-induced MVs formed as a function of the crystal orientation and thermomechanical parameters of the shape memory alloy (SMA) with higher accuracy than when using the criteria separately. To validate our criteria, we tested other researchers published results. Our results were in agreement and were capable of predicting the stress-induced MVs in a polycrystalline SMA.The authors wish to thank the Coordinacion de estudios de posgrado (CEP)-UNAM, PAPIIT project number TI 02414 and Instituto de Tecnologia de Materiales-UPV for financial support. The authors are grateful to the Electron Microscopy Service of the UPV and especially to Manuel Josep Planes Insausti and Jose Luis Moya Lopez. The authors are grateful to Martin Estrada Arcos, Alberto Higuera Garcia, and Antonio Gonzalez Montaiio for their technical support.García Castillo, F.; Cortés Pérez, J.; Amigó Borrás, V.; Sánchez Arévalo, P.; Lara Rodríguez, G. (2015). Development of a stress-induced martensitic transformation criterion for a Cu-Al-Be polycrystalline shape memory alloy undergoing uniaxial tension. Acta Materialia. 97:131-145. https://doi.org/10.1016/j.actamat.2015.06.044S1311459

Experimental study of bore-driven swash hydrodynamics on permeable rough slopes

Peer reviewedPublisher PD

Biogeochemical markers across a pollution gradient in a Patagonian estuary: A multidimensional approach of fatty acids and stable isotopes

A combined approach merging stable isotopes and fatty acids was applied to study anthropogenic pollution in the Río Negro estuary. Fatty acid markers of vegetal detritus indicated considerable allochthonous inputs at freshwater sites. Correlative evidence of diatom fatty acids, δ13C, chlorophyll and particulate organic matter suggested the importance of diatoms for the autochthonous organic matter production at the river mouth. Low δ15N values (~0�) and high fatty acid 18:1(n-7) concentrations in the suspended particulate matter, in combination with the peaks of coliforms and ammonium, indicated a strong impact of untreated sewage discharge. The 15N depletion was related to oxygen-limited ammonification processes and incorporation of 15N depleted ammonium to microorganisms. This work demonstrates that the combined use of lipid and isotopic markers can greatly increase our understanding of biogeochemical factors and pollutants influencing estuaries, and our findings highlight the urgent need for water management actions to reduce eutrophication

A replication-casting device for manufacturing open-cell Mg foams

The development of a replication casting device with the capability of manufacturing open-cell pure Mg and Mg alloys foams, with melting points lower than 950 °C is described. The device consists of three basic parts: a cylindrical reaction chamber, a valve system for controlling the vacuum and the gas injection, and a heating system. The purpose of the present design was to improve the existing laboratory-scale devices, making them simpler than those reported in the literature, as well as to optimize the parameters (atmosphere, temperature, injection pressure, etc.) of the replication casting process. The proposed device has shown significant improvement over other devices reported, especially in terms of easiness of operation, adjustability and low cost of maintenance. The design of the device provides the ability to produce large foams free from defects such as large volumetric shrinkage and large concavities. The latter is minimized by the implementation of a perforated nozzle for gas impulsion. Examples of manufactured open-cell pure Mg and Mg–10 wt.% Al alloy foams are also presented. The design is shown in a conceptual format; however it could be modified to produce larger or smaller samples

Protist taxonomic and functional diversity in soil, freshwater and marine ecosystems

Protists dominate eukaryotic diversity and play key functional roles in all ecosystems, particularly by catalyzing carbon and nutrient cycling. To date, however, a comparative analysis of their taxonomic and functional diversity that compares the major ecosystems on Earth (soil, freshwater and marine systems) is missing. Here, we present a comparison of protist diversity based on standardized high throughput 18S rRNA gene sequencing of soil, freshwater and marine environmental DNA. Soil and freshwater protist communities were more similar to each other than to marine protist communities, with virtually no overlap of Operational Taxonomic Units (OTUs) between terrestrial and marine habitats. Soil protists showed higher γ diversity than aquatic samples. Differences in taxonomic composition of the communities led to changes in a functional diversity among ecosystems, as expressed in relative abundance of consumers, phototrophs and parasites. Phototrophs (eukaryotic algae) dominated freshwater systems (49% of the sequences) and consumers soil and marine ecosystems (59% and 48%, respectively). The individual functional groups were composed of ecosystem- specific taxonomic groups. Parasites were equally common in all ecosystems, yet, terrestrial systems hosted more OTUs assigned to parasites of macro-organisms while aquatic systems contained mostly microbial parasitoids. Together, we show biogeographic patterns of protist diversity across major ecosystems on Earth, preparing the way for more focused studies that will help understanding the multiple roles of protists in the biosphere