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. 相似文献
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. 相似文献
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, σw0, 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. 相似文献
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. 相似文献
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. 相似文献
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. 相似文献
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. 相似文献
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.