Modeling tensile strength of materials processed by accumulative roll bonding

Nanostructured materials are a relatively new class of materials that exhibit advanced mechanical properties, thus improving performance and capabilities of products, with potential applications in the automotive, aerospace and defense industries. Among the severe plastic deformation (SPD) methods currently used for achieving nanoscale structures, accumulative roll bonding (ARB) is the most favorable method to produce grain refinement for continuous production of metallic sheets at a bulk scale.In this article, a model that describes the evolution of material strength due to processing via accumulative roll bonding was developed. ARB experiments were conducted on CP-Ti Grade 2 at a selected set of conditions. The results showed significant grain refinement in the microstructure (down to ～120 nm) and a two-fold increase in tensile strength as compared to the as-received material. The developed model was validated using the experimental data, and exhibited a good fit over the entire range of ARB processing cycles. To further validate the model and ensure its robustness for a wider array of materials (beyond CP-Ti), a review of efforts on ARB processing was carried out for five other materials with different initial microstructures, mechanical properties, and even crystalline structures. The model was still able to capture the strengthening trends in all considered materials.     

Blood markers among residents from a coal mining area

Environmental Science and Pollution Research - Coal extraction and processing generate environmental contamination, which has several negative impacts on human health. Hematological and biochemical...     

Assessment of Surface Disinfection Effectiveness of Decontamination System COUNTERFOG® SDR-F05A+ Against Bacteriophage ɸ29

Food and Environmental Virology - The experience of COVID19 pandemic has demonstrated the real concern of biological agents dispersed in the air and surfaces environments. Therefore, the need of a...     

Silica-quaternary ammonium “Fixed-Quat” nanofilm coated fiberglass mesh for water disinfection and harmful algal blooms control

Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of receiving surface waters. Formation of unwanted disinfection by-products(DBPs) resulting from conventional disinfection technologies reveals the need for the development of new sustainable alternatives. Quaternary Ammonium Compounds(QACs) are cationic surfactants widely known for their effective biocidal properties at the ppm level. In this study, a novel silica-based antimicrobial nanofilm was developed using a composite of silica-modified QAC(Fixed-Quat) and applied to a fiberglass mesh as an active surface via sol–gel technique. The synthesized Fixed-Quat nanocoating was found to be effective against E. coli with an inactivation rate of 1.3 × 10~(-3) log reduction/cm min. The Fixed-Quat coated fiberglass mesh also demonstrated successful control of Microcystis aeruginosa with more than 99% inactivation after 10 hr of exposure.The developed antimicrobial mesh was also evaluated with wild-type microalgal species collected in a water body experiencing HABs, obtaining a 97% removal efficiency. Overall,the silica-functionalized Fixed-Quat nanocoating showed promising antimicrobial properties for water disinfection and HABs control, while decreasing concerns related to DBPs formation and the possible release of toxic nanomaterials into the environment.     

Use of oleaginous plants in phytotreatment of grey water and yellow water from source separation of sewage

Efficient and economic reuse of waste is one of the pillars of modern environmental engineering. In the field of domestic sewage management, source separation of yellow (urine), brown (faecal matter) and grey waters aims to recover the organic substances concentrated in brown water, the nutrients (nitrogen and phosphorous) in the urine and to ensure an easier treatment and recycling of grey waters. With the objective of emphasizing the potential of recovery of resources from sewage management, a lab-scale research study was carried out at the University of Padova in order to evaluate the performances of oleaginous plants (suitable for biodiesel production) in the phytotreatment of source separated yellow and grey waters. The plant species used were Brassica napus (rapeseed), Glycine max (soybean) and Helianthus annuus (sunflower). Phytotreatment tests were carried out using 20 L pots. Different testing runs were performed at an increasing nitrogen concentration in the feedstock. The results proved that oleaginous species can conveniently be used for the phytotreatment of grey and yellow waters from source separation of domestic sewage, displaying high removal efficiencies of nutrients and organic substances (nitrogen > 80%; phosphorous > 90%; COD nearly 90%). No inhibition was registered in the growth of plants irrigated with different mixtures of yellow and grey waters, where the characteristics of the two streams were reciprocally and beneficially integrated.     

Sex pheromone component ratios and mating isolation among three Lygus plant bug species of North America

The plant bugs Lygus hesperus, Lygus lineolaris, and Lygus elisus (Hemiptera: Miridae) are major pests of many agricultural crops in North America. Previous studies suggested that females release a sex pheromone attractive to males. Other studies showed that males and females contain microgram amounts of (E)-4-oxo-2-hexenal, hexyl butyrate, and (E)-2-hexenyl butyrate that are emitted as a defense against predators. Using gas chromatography–mass spectrometry, we found that female L. lineolaris and L. elisus have a 4:10 ratio of hexyl butyrate to (E)-2-hexenyl butyrate that is reversed from the 10:1 ratio in female L. hesperus (males of the three species have ~10:1 ratio). These reversed ratios among females of the species suggest a behavioral role. Because both sexes have nearly equal amounts of the major volatiles, females should release more to attract males. This expectation was supported because L. hesperus females released more hexyl butyrate (mean of 86 ng/h) during the night (1800–0700 hours) than did males (<1 ng/h). We used slow-rotating pairs of traps to test the attraction of species to blends of the volatiles with a subtractive method to detect synergism. Each species’ major butyrate ester was released at 3 μg/h, the minor butyrate according to its ratio, and (E)-4-oxo-2-hexenal at 2 μg/h. The resulting catches of only Lygus males suggest that (E)-4-oxo-2-hexenal is an essential sex pheromone component for all three species, (E)-2-hexenyl butyrate is essential for L. elisus and L. lineolaris, and hexyl butyrate is essential for L. hesperus. However, all three components are recognized by each species since ratios of the butyrate esters are critical for conspecific attraction and heterospecific avoidance by males and thus play a role in reproductive isolation among the three species. Because L. hesperus males and females are known to emit these major volatiles for repelling ant predators, our study links defensive allomones in Lygus bugs with an additional use as sex pheromones.     

SO2 gas adsorption by modified kaolin clays: influence of previous heating and time acid treatments

Modified kaolin clays were used as adsorbents for SO(2) gas adsorptions. The clays were heated up to 900 °C previous to acid treatments with 0.5 N sulfuric acid solutions at boiling temperature during different times up to 1440 min. Equilibrium adsorption at 25 °C and 0.1 MPa was carried out by using a volumetric apparatus. The samples were characterized by chemical analysis, X-ray diffraction and infrared analysis. The heating of the clays followed by acid treatment improved the adsorption capacity of the kaolin clays. The presence of amorphous silica and hydroxyl in the final products improved SO(2) adsorption capacity. Better properties for SO(2) adsorption were found in kaolin rich in not well ordered kaolinite clay mineral.     

Prediction of particulate air pollution from a landfill site using CFD and LIDAR techniques

Landfill sites have been the most common way of eliminating solid urban waste, as well as that of public and mining wastes. Landfill sites are a constant source of environmental pollution and wind is the most important contributing factor to air pollution, due to the erosion which it produces over the landfill site surfaces, transporting dust away from the source point. This causes serious risks for human health and general dirt in the surrounding areas of the landfill site. The result of dust air pollution produced in a landfill site is analysed through CFD3D (Computational Fluid Dynamics) by joining the LIDAR (Light Detection and Ranging) technique and Ansys CFX 10.0 software. The CFD simulations determine the wind velocity distribution on the landfill site surface and the different particle threshold friction velocities which determine the dust emission in multiphase simulations (air-particles). These simulations are validated from field data obtained in three measurement programmes for each type of landfill site surface treatment which has been studied. It was determined that the superficial landfill site treatment with the lowest air pollution is tall grass and bushes. The methodology used can be applied to the dust emission calculation in the design or evaluation of other landfill sites.     

House sparrows selectively eject parasitic conspecific eggs and incur very low rejection costs

Most host species of obligate interspecific brood parasites are under strong selection because such parasitism, e.g., that involving evictor nestmates, is highly costly. Egg rejection is one of the most efficient host defences against avian brood parasites. Many hosts have thus evolved egg-recognition ability and rejection behaviour. However, this defensive mechanism has not evolved in most species where only intraspecific brood parasitism occurs, probably because (1) the eggs of conspecific females are very similar in appearance, making egg rejection less likely to emerge, and (2) such parasitism is frequently less costly than interspecific parasitism. Using a captive population of house sparrows (Passer domesticus) with a low breeding density, we here provide new evidence showing that this species actually has a fine capacity to discriminate conspecific eggs and to eject them (44.2% of foreign eggs ejected) while incurring very low rejection costs (4.2% of own eggs ejected). This result contradicts those previously found in high-density house sparrow populations in which very high rejection costs and very high clutch desertion rates were reported, probably as a consequence of intraspecific competition and infanticide provoked by the high breeding density. The house sparrow has only rarely been reported as the host of an interspecific brood parasite, which implies that it is a newly described example of an altricial species in which egg ejection has evolved and is maintained in response to intraspecific brood parasitism.     

Oxidative stress in Nile tilapia (Oreochromis niloticus) and armored catfish (Pterygoplichthys anisitsi) exposed to diesel oil

Considering that diesel oil is one of the most common aquatic contaminants, we compare the oxidative stress between two species of fish with different habitats (Pterygoplichthys anisitsi, benthic and Oreochromis niloticus, nektonic) exposed to diesel oil. Malondialdehyde concentrations (MDA) and the activities of ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase were all analyzed in the fishes' livers and gills after 2 and 7 days of exposure to different concentrations of diesel (0.1 and 0.5 mL/L). In the tilapia, MDA levels and the activities of EROD and GST activity in the liver, as well as MDA levels and the activities of GST and SOD in the gill had statistically significant differences between the treatments and between the times of exposure. For the catfish, the same occurred in the case of MDA, EROD, and SOD in the liver and in CAT and SOD in the gills. There were significant differences in the enzyme activity and lipid peroxidation between the species. Although the activity of most enzymes seemed to be more expressive and responsive to diesel in O. niloticus, diesel oil also caused significant effects on oxidative stress parameters in P. anisitsi, even though this species is benthic and thus has less access to insoluble fractions of diesel oil. Therefore, both species can be used as sentinel organisms in environmental biomonitoring of diesel contamination.