Ozonation of a landfill leachate: evaluation of toxicity removal and biodegradability improvement

This work shows an evaluation of treatments for the leachate produced at the Gramacho Municipal Landfill in Rio de Janeiro state, Brazil. This leachate has very peculiar characteristics, with a high salinity level and very low biodegradability (BOD(5)/COD of 0.05). A sequence of processes was employed in the treatment of this leachate. Initially, a physicochemical treatment was used, while the second stage consisted of application of ozone to improve the biodegradability of the leachate. The final stage comprised a biological treatment. The physical-chemical treatment led to COD and DOC removal levels of 40 and 25%, respectively, with the use of Al(2)(SO(4))(3). The sequence of treatments proposed brought good results, with an increase in the BOD(5)/COD ratio from 0.05 to 0.3 after ozonation. The toxicity tests performed using Brachydanio rerio and Poecilia vivipara showed that the toxicity of the leachate had hardly been reduced by ozonation. These results are in agreement with the fact that, despite the higher BOD(5)/COD ratio, the biological process did not present a good performance. The total average removal levels of COD and DOC achieved using the combined treatment were 73 and 63%, respectively, for an ozone dose of 3.0 gL(-1) by the leachate.     

Plutonium Loading of Prospective Grouped Actinide Extraction (GANEX) Solvent Systems based on Diglycolamide Extractants

The Grouped Actinide Extraction (GANEX) process is being developed for actinide recycling within future nuclear fuel cycles. Interactions between potential solvents and macro-concentrations of plutonium are one of the most important issues in defining the GANEX process. Surprisingly, plutonium loading of diglycolamide (DGA) based solvents such as tetra-octyl DGA (TODGA) causes precipitation rather than a conventional third phase, in direct contrast to results with U(VI), Th(IV) or lanthanide ions. Various DGA based solvent systems have been screened for their plutonium loading capacity and 0.2 M TODGA with 0.5 M DMDOHEMA in a kerosene diluent is selected as the optimum solvent formulation of those tested. Plutonium can be relatively easily stripped from this solvent using aqueous acetohydroxamic acid but this is very acid dependent in the low acidity region.     

Synthesis of compatibilizers and characterization of the compatibilized and noncompatibilized blends of PP/Rodrun LC3000

The addition of a liquid crystalline polymer (LCP) to a matrix of a flexible thermoplastic (TP) has been used in the last two decades as an in situ reinforcement of the matrix. Owing to the immiscibility of the two phases and the high degree of orientation typical of LCPs, the dispersed phase is, after processing, essentially constituted by fibrillar structures, which are responsible for the reinforcement of the matrix and the decrease of viscosity with respect to the matrix. The low degree of adhesion typical of LCP/TP blends often requires the use of compatibilizers, which will act reducing the interfacial tension between the two components. In this work, we present the synthesis of three different compatibilizers, as well as the mechanical characterization of the corresponding compatibilized blends. Some scanning electron microphotographs will be also presented to better explain the mechanical results. The mechanical properties of these blends were compared with the noncompatibilized blend, as well as with the ones presented by blends obtained with two commercial compatibilizers, leading to the conclusion that, considering our compatibilizer C, the one that leads to the higher enhancement of the Young's modulus, when compared with the noncompatibilized blend, we obtain a Young's modulus 27% higher than the one presented by the noncompatibilized blend. Comparing this result with those presented by the blends compatibilized with the two commercial compatibilizers, D and E, we conclude that this enhancement is higher than those presented by those blends (increase in Young's modulus of 16% for both compatibilizers). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influence of Graphite Nodules Geometrical Features on Fatigue Life of High-Strength Nodular Cast Iron

This paper is concerned with the evaluation of different fatigue strength theories to predict the fatigue life of high-strength nodular cast iron. There have been some studies on the effects of the shape and size of graphite nodules, and of microstructure, on the fatigue strength of nodular cast iron. However, there is not a consensus on how to correlate the fatigue limit with material intrinsic properties or with external features such as considering graphite nodules as defects. Some researchers found good correlations between fatigue strength, σ_w0, and the geometrical aspects of the graphite nodules, considering it as internal material defects. It will be shown in this study that geometrical features such as shape, size, and relative position seem to be adequate to be included in those predictions. In this article, a high-strength cast iron, with rupture strength of about 1300 MPa and Young’s modulus of about 160 GPa, has been used. Correlations both with intrinsic properties as well as with other geometrical effects have been made. A comparison of different theories has also been carried out. This article was presented at Materials Science & Technology 2007, Automotive and Ground Vehicles symposium held September 16–20, 2007, in Detroit, MI.     

Intercomparison of the Realization of the ITS-90 at the Freezing Points of Al and Ag among European NMIs

The EUROMET.T-K4 comparison is the regional extension of CCT-K4, an intercomparison of the realizations of the freezing points of Al (660.323°C) and Ag (961.78°C). The intercomparison was organized in four loops. Long-stem standard platinum resistance thermometers (SPRTs) were used as traveling standards: 25 Ω thermometers to be used only at the Al freezing point and two high-temperature standard platinum resistance thermometers (HTSPRTs) to be used only at the Ag freezing point in each loop. Parallel to the measurements with thermometers, the pilots and sub-pilots organized an internal intercomparison using an Ag fixed-point cell. Most HTSPRTs showed a strong drift which is mainly due to mechanical stress and poisoning of the sensor by impurities. This drift can be partially compensated by a correction based on Matthiessen’s rule. An evaluation of the data taking into account both HTSPRTs in each loop, the linkage of the sub-pilots by measurements at the Ag freezing point, and a possible compensation according to Matthiessens’s rule, allows calculation of the results of the participants’ measurements at the Ag freezing point. The results of the participating laboratories are summarized, and proposals for key comparison reference values and linking of the results to CCT-K3 and CCT-K4 are presented.     

Optical fibre-based micro-analyser for indirect measurements of volatile amines levels in fish

An analytical method based on optical fibre (OF) detection has been developed and validated for monitoring of trimethylamine (TMA) and dimethylamine (DMA) in fish handling environments and for non invasive assessment of fish quality.     

Measurement of concrete E-modulus evolution since casting: A novel method based on ambient vibration

The use of ambient vibration tests to characterize the evolution of E-modulus of concrete right after casting is investigated in this paper. A new methodology is proposed, which starts by casting a concrete cylindrical beam inside a hollow acrylic formwork. This beam is then placed horizontally, simply supported at both extremities, and vertical accelerations resulting from ambient vibration are measured at mid-span. Processing these mid-span acceleration time series using power spectral density functions allows a continuous identification of the first flexural frequency of vibration of the composite beam, which in turn is correlated with the evolutive E-modulus of concrete since casting. Together with experiments conducted with the proposed methodology, a complementary validation campaign for concrete E-modulus determination was undertaken by static loading tests performed on the composite beam, as well as by standard compressive tests of concrete cylinders of the same batch loaded at different ages.     

Fracture Mechanics Tests in Adhesively Bonded Joints: A Literature Review

Fracture mechanics characterization tests for adhesive joints are analyzed and reviewed in order to understand their advantages and disadvantages. Data reduction techniques for analytical methods are summarized to understand the improvements implemented in each test. Numerical approaches are also used complementing tests information. Both linear and non-linear methods to obtain the fracture energy release rate are presented. Pure mode I and mode II tests are described. Simple mixed-mode tests, varying only the specimen geometry, with limited mode-mixity are also presented. Performing a wider mode-mixity range requires sophisticated apparatus that are studied in detail. There is no general agreement about the test suitability for mixed-mode fracture assessment of adhesive joints. A universal test that can easily be performed and give accurate results is essential to optimize the expensive testing at the design stage.     

Synthesis of Chalcogenophenes via Cyclization of 1,3‐Diynes Promoted by Iron(III) Chloride and Dialkyl Dichalcogenides

In this paper, we report the iron(III) chloride and dibutyl diselenide‐mediated cyclization of 1,3‐diynes which leads to 3,4‐bis(butylselanyl)selenophenes. The optimization studies showed that the reaction was best performed with equimolar amounts of iron(III) chloride and dibutyl diselenide in dichloromethane at 40 °C for 4 h. The method allows the synthesis of symmetrical and unsymmetrical selenophenes in moderate to good yields. A similar protocol was also extended to the synthesis of thiophene derivatives using dimethyl disulfide instead of dibutyl diselenide. The resulting selenophenes and thiophenes were further functionalized by selenium–halogen exchange reactions, Sonogashira cross‐coupling reactions and electrophilic cyclizations.