MIG Brazing of Galvanized Thin Sheet Joints for Automotive Industry

MIG welding of zinc-coated thin plates in the automotive industry leads to major issues, mainly zinc evaporation followed by a decrease of corrosion resistance, as well as residual strains and stresses difficult to minimize. The use of a lower heat input technique for joining galvanized steels would bring significant benefit, if the final overall mechanical properties of the joints are adequate for the application. The use of MIG brazing (MIGB) with the recently commercialized alloyed copper-based filler metal is an alternative worth considering. The present paper addresses the MIGB processes, describing the influence of the different shielding gases and the process parameters on the mechanical, corrosion, and metallurgical properties of the joint, when lower heat input procedures are targeted. The paper describes the influence of the gases on the mechanical properties of the brazed joint, both in normal conditions after joining and after corrosion in a salt water environment. Microstructural features of the different zones are discussed. Results of corrosion and tensile tests are presented and interpreted.     

Increases in nitrogen use efficiency decrease nitrous oxide emissions but can penalize yield in sugarcane

Nutrient Cycling in Agroecosystems - Nitrogen (N) fertilization strategies focused on increasing nitrogen use efficiency (NUE) and decreasing nitrous oxide (N2O) emissions are important for...     

Auctioning wind power sites when environmental quality matters

In this work, we propose an index that allows a public authority to order different projects for the construction of onshore wind energy plants and that explicitly takes into account their environmental quality. Wind farm projects are defined as vectors of four attributes: the technical properties of each project, its social impact, its environmental impact, and the share of earnings that proponents offer to the collectivity in compensation for the negative externalities of the wind plant. We define an absolute index that allows the ordering of different proposals and evaluation of the acceptability of each project, providing the monetary value of each point and inducing a truthful revelation of firms' private information. Moreover, we calibrate the index on the basis of data referring to wind plants in Southern Italy and derive the corresponding iso-scoring curves.     

Linguistic analysis of an assertiveness training film.

Analyzed stylistic complexity and verb usage in the text of the film Responsible Assertion, an assertiveness training film, using the Computer-Assisted Language Analysis System. Findings suggest that the assertive language in the film was characterized by a wordy, complex style full of many embedded clauses and that assertive speech consisted of monologues containing qualifying phrases. Results suggest that assertiveness trainers should emphasize wordiness and persistence rather than simple sentences. Data indicate that an emphasis on feelings was not crucial in behavior that was judged assertive. Implications for understanding the process and outcome of therapy are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating forage quantity and quality under different stress and senescent biomass conditions via spectral reflectance

Assessing forage quantity and quality through remote sensing can facilitate grassland and pasture management. However, the high spatial and temporal variability of canopy conditions may limit the predictive accuracy of models based on reflectance measurements. The objective of this work was to develop this type of models, and to challenge their capacity to predict plant properties under a wide range of environmental conditions. We manipulated Paspalum dilatatum canopies through different stress treatments (flooding, drought, nutrient availability, and control) and by artificially varying the amount of senescent biomass. We measured canopy reflectance and constructed simple models, based on either normalized vegetation indices or a few selected wavebands, to estimate biomass and two variables related to forage quality: proportion of photosynthetic vegetation and biomass C:N ratio. General models satisfactorily predicted plant properties for the whole set of environmental conditions, but failed under specific conditions such as drought (for estimates of plant biomass), fertilization (for estimates of C:N ratio), and different levels of senescent tillers (for estimates of the proportion of photosynthetic vegetation). Where general models failed, specific models, based on different bands, achieved satisfactory accuracy. The general models performed better when based on a few selected bands than when based on two-band vegetation indices, having better accuracy (higher R²) and parsimony (lower BIC). However specific models performed similarly for both approaches (similar R² and BIC). These results indicate that these plant properties can be predicted from reflectance information under a broad range of conditions, but not for some particular conditions, where ancillary data or more complex models are probably needed to increase predictive accuracy.     

Large mass bolometric detectors for double-beta decay experiments

The authors have developed bolometric detectors with masses of 5.5 g, 20.9 g, and 34 g using TeO₂ crystals for the investigation of ¹³⁰Te, and are developing CaF₂ detectors for double-beta decay search in ⁴⁸Ca, using the luminescence properties of the crystal to improve background rejection. Scintillation of a CaF₂ crystal with 0.03% of Eu doping was observed at 20 mK. A 2.1-g, 0.01%-Eu-doped crystal was used as a bolometer, and a resolution of 50 keV for the double escape peak of ²³²Th was obtained at 60 mK, showing a negligible contribution of the Eu atoms to the crystal heat capacity. Simultaneous detection of light and phonons will allow an efficient background rejection of the ²³⁸U to ²³⁴Th α decay from the ²³⁸U natural series occurring at almost the same energy of the ⁴⁸Ca transition. Background rejection is necessary as even uranium contamination as low as 10^m-10 g/g would make the search impossible     

Struma cordis: first case in Mexico

The Intracardiac ectopic thyroid is an extremely rare condition and there is no previous report on this subject in Mexico. This is the case of a 33 years old woman, with normal thyroid function. She was found to have an intracardiac tumor in the interventricular septum. The intraoperative biopsy showed typical thyroid follicules; tumor removal left a septal defect that was closed with a dacron patch suture. Two years follow-up showed normal echocardiographic images, good clinical status an normal thyroid functioning. A brief review of the literature is included.     

Electrochemical behaviour of iron and iron oxide thin films in alkaline (1 m KOH) aqueous solution: a voltammetry study for cathodic instability of coating/metal interface

The electrochemical behaviour of thin film metallic iron and the iron oxides in 1 m KOH anaerobic aqueous solution was studied by cyclic voltammetry technique. The material studied was of thin film (50 nm) iron supported on a glass substrate, and the oxide thermally formed on the iron film. The voltammetry of thin film iron on glass was similar to that of low carbon steel and gave a convenient means for preparing specimens for obtaining information relevant to the degradation of structural steel. In this report, the formation of various types of oxides on the iron surface are identified, and the electrochemical stability of the oxides and their relevance to the cathodic disbonding of organic coating from cathodically protected steel pipelines are discussed.     

Synthesis, optical characterization and crystal and molecular X-ray structure of a phenylazojulolidine derivative

The synthesis, spectroscopic characterization, and X-ray crystal structure of [4-(2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-ylazo)-phenyl]-methanol azodye are reported. A 37-47 nm bathochromic shift has been observed by comparison with analogous azodyes where diethylamino or dimethylamino groups act as donor moiety in agreement with the larger electronic donating properties of julolidine. The azobenzene skeleton adopts a planar trans-configuration and intra- and inter-molecular hydrogen bonds have been detected. A correlation between the spectroscopic and the molecular features has been attempted.     

Retention of limulus amoebocyte lysate reactive bacterial products by polysulfone dialyzers is affected by the type of disinfectant

To reduce the level of contamination by bacterial products, ultrafiltration systems have been introduced and validated for their capacity to block the passage of bacterial components reactive to the limulus amoebocyte lysate (LAL) test. In this study, the absorptive capacity of polysulfone membranes undergoing disinfection cycles with free chlorine and peracetic acid were evaluated at various concentrations and contact times. The results of this study implicate a relevant physicochemical derangement of the polysulfone membranes treated with sodium hypochlorite but not with peracetic acid, diluted peracetic acid (Dialox) or Amuchina. The implications for the practical use of ultrafilters are discussed.