Degradation of the compressive strength of rectangular plates due to initial deflection

The paper addresses the problem of the influence of initial deflections on the collapse strength of thin rectangular plates in longitudinal compression. Measured data on distortions of stiffened plating in ships are considered in studying the strength of plates. For comparison of the strength values, the initial deflections are normalised by an energy measure and by the commonly employed amplitude to thickness ratio. It is suggested that this energy measure is able to provide an integral measure of the degree of initial deflections.     

Flood Control in the Cuiabá River Basin, Brazil, with Multipurpose Reservoir Operation

Periodic flooding in the Cuiabá River Basin (CRB), which is located in the upper Pantanal region, in central-western Brazil, led to the construction of the Manso multipurpose reservoir and power plant. This study evaluates the influence of the Manso reservoir on the attenuation of downstream flooding specifically in the metropolitan area of Cuiabá, which is the capital city of the state of Mato Grosso. The flood routing provided by the Manso reservoir was simulated by means of the Puls modified method (level-pool routing method), and the translation of the flood wave during floodplain passage was calculated with the CLiv hydrodynamic model for critical hydrological events. It is demonstrated that the reservoir reduces the frequency of flood risk to downstream communities for return periods between 50 and 100 years. Despite the flood attenuation, other measures should be undertaken in addition to the reservoir operation to mitigate the impacts of flooding in a comprehensive and appropriate way. In particular, measures related to floodplain land use planning and management are important to ensure that the safety of the population does not exclusively depend on the upstream reservoir.     

Milk Drink Using Whey Butter Cheese (queijo manteiga) and Acerola Juice as a Potential Source of Vitamin C

The production of a beverage from whey butter cheese (WBC) and acerola juice (AJ) presents good commercialization potential, uniting the benefits provided by the former with those of latter, including the ingestion of essential amino acids and increasing the vitamin C content, resulting in a product of differentiated nutritive value. Three beverage formulations were developed: B₁ (50% WBC–50% AJ v/v), B₂ (70% WBC–30% AJ, v/v), and B₃ (30% WBC–70% AJ, v/v). Lower protein and carbohydrate values were found for the formulations with less whey (p < 0.05). All the beverages presented an energy value below those declared for dairy beverages commercialized on the Brazilian market. The beverages B₁ and B₂ were considered food products that were sources of vitamin C. B₂ presented significant variations for all the sensory attributes evaluated (p < 0.05), although the results were similar to those obtained for B₁, suggesting the commercialization potential of these formulations.     

Electrochemical and morphologic studies of nickel incorporation on graphite electrodes modified with polytyramine

Electrodes modified with electropolymerized films have received considerable attention in the development of catalysts and sensors, and their use is rapidly increasing. This work reports modification of the surface of graphite electrodes by electrochemical polymerization of tyramine. These modified electrodes were used to nickel incorporation and hydrogen evolution. Tyramine electrooxidation, in acid and basic media, yielded polymeric films onto graphite surface. In ferrocyanide/ferricyanide solution, the electrodes modified in acid medium showed higher electron transfer efficiency. Impedance studies indicated higher charge transfer resistance to electrodes modified with Ptyr prepared in basic pH. Scanning electron microscopy showed that the formed films present different morphology for the several pH values studied. Interferometry and scanning electron microscopy analysis showed higher coverage to films formed in acid medium. Polymers produced in more alkaline medium present growth self-limited. Nickel was incorporated in the films through immersion of the modified electrodes in solution of potassium hexafluoronickelate, followed of electrochemical reduction of the metal. The electrocatalytic activity of the modified electrodes with nickel incorporated was tested for hydrogen evolution reaction. The amount of nickel mass incorporated as well as the current density of hydrogen evolution reaction was higher in electrodes modified with polytyramine produced in acid medium.     

Engineering graphics and watermills: Ancient technology in Spain

This article shows the hydraulic and mechanical study of the turbine of a typical Spanish watermill. The mill in question is located in Alcalá La Real (Jaén, Spain), and shows the common characteristics of Spanish watermills. Given its state of abandonment, we developed a virtual model of the mill, in 3D and with computer animation which helps to show how the mill worked. We also give a comparison with Spanish windmills, showing way the two types of technology coexisted as a way of milling grain, and we give data on the performance of both technologies     

Preservation of aseptic conditions in absorbent pads by using silver nanotechnology

Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology.     

Sigmoidal thermal inactivation kinetics of Listeria innocua in broth: Influence of strain and growth phase

Listeria innocua inactivation was studied within the temperature range 52.5–65.0 °C, comparing two different strains (10528 and 2030c) and two growth phases (exponential and stationary). Survival curves may present a sigmoidal behaviour, with an initial shoulder (L), followed by a maximum inactivation rate (k_max) period and a final tailing tendency. A Gompertz-inspired model was used to fit experimental data, and kinetic parameters (L, k_max and tail) were estimated by non-linear regression analysis. The influence of temperature, growth phase and strain on kinetic parameters was studied using a 2³ factorial experimental design. Results showed that temperature and growth phase were the most significant variables affecting the kinetic parameters. Listeria thermal inactivation varied from a log-linear tendency till a pronounced sigmoidal behaviour, depending on the studied factors.     

Activation of the Interleukin-33/ST2 Pathway Exerts Deleterious Effects in Myxomatous Mitral Valve Disease

Mitral valve disease (MVD) is a frequent cause of heart failure and death worldwide, but its etiopathogenesis is not fully understood. Interleukin (IL)-33 regulates inflammation and thrombosis in the vascular endothelium and may play a role in the atherosclerotic process, but its role in mitral valve has not been investigated. We aim to explore IL-33 as a possible inductor of myxomatous degeneration in human mitral valves. We enrolled 103 patients suffering from severe mitral regurgitation due to myxomatous degeneration undergoing mitral valve replacement. Immunohistochemistry of the resected leaflets showed IL-33 and ST2 expression in both valve interstitial cells (VICs) and valve endothelial cells (VECs). Positive correlations were found between the levels of IL-33 and molecules implicated in the development of myxomatous MVD, such as proteoglycans, extracellular matrix remodeling enzymes (matrix metalloproteinases and their tissue inhibitors), inflammatory and fibrotic markers. Stimulation of single cell cultures of VICs and VECs with recombinant human IL-33 induced the expression of activated VIC markers, endothelial–mesenchymal transition of VECs, proteoglycan synthesis, inflammatory molecules and extracellular matrix turnover. Our findings suggest that the IL-33/ST2 system may be involved in the development of myxomatous MVD by enhancing extracellular matrix remodeling.