Effect of local stiffeners and warping constraints on the buckling of symmetric open thin-walled beams with high warping stiffness

Local stiffeners affect the behaviour of thin-walled beams (TWBs). An in-house code based on a one-dimensional model proved effective in several instances of compressive buckling of TWBs but gave counterintuitive results for locally stiffened TWBs. To clarify the matter, we investigated TWBs with multi-symmetric double I cross-section, widely used in practical applications where high bending stiffness is required. Several samples were manufactured and stiffened on purpose, closing them over a small portion of the axis at different places. The samples were tested with end constraints accounting for various warping conditions. The experimental and numerical outputs from a commercial FEM code gave a key to overcome the unexpected results by the in-house code, paving the way for further studies

Environmentally safe ZVI/ZnS-based polymer composite for lindane degradation in water: Assessment of photocatalytic activity and eco-toxicity

Monolithic composite aerogel based on a photocatalytic system, constituted by Fe0 (ZVI) coupled with ZnS (FZ), embedded into syndiotactic polystyrene (sPS) matrix was used, for the first time, in the lindane degradation under UV light. The content of FZ photocatalyst inside the monolithic composite aerogel (FZsPS) composite was 3 wt%. FESEM images of FZsPS indicate that the FZ photocatalyst is well dispersed in the polymer matrix. EDS analyses and temperature-programmed reduction (TPR-H2) measurements revealed an interpenetrated structure of the ZVI and ZnS phases as well the presence of some iron in an oxidized form. Photocatalytic activity data showed that in presence FZsPS aerogel, the almost complete lindane degradation was achieved after only 30 min of UV irradiation time. FZsPS was also effective in the lindane mineralization since a TOC removal of about 94 % was detected after 180 min of treatment time. Remarkably, based on the toxicity evaluation on Artemia fran-ciscana, while the bare FZ photocatalyst showed significant toxicity per se, no toxicity or genotoxicity was found in the water treated with the FZsPS composite system where FZ is immobilized into the sPS aerogel matrix. Therefore the proposed composite photocatalyst can be considered as a model for a strategy to eliminate the environmental impact of catalysts that would otherwise be harmful to water

Antimicrobial Effectiveness of Innovative Photocatalysts: A Review

Waterborne pathogens represent one of the most widespread environmental concerns. Conventional disinfection methods, including chlorination and UV, pose several operational and environmental problems; namely, formation of potentially hazardous disinfection by-products (DBPs) and high energy consumption. Therefore, there is high demand for effective, low-cost disinfection treatments. Among advanced oxidation processes, the photocatalytic process, a form of green technology, is becoming increasingly attractive. A systematic review was carried out on the synthesis, characterization, toxicity, and antimicrobial performance of innovative engineered photocatalysts. In recent decades, various engineered photocatalysts have been developed to overcome the limits of conventional photocatalysts using different synthesis methods, and these are discussed together with the main parameters influencing the process behaviors. The potential environmental risks of engineered photocatalysts are also addressed, considering the toxicity effects presented in the literature

Effects of mineral amendments on trace elements leaching from pre-treated marine sediment after simulated rainfall events

Bauxite extraction by-products (red mud) were used to evaluate their potential ability to stabilize trace elements from dredged and aerated/humidified marine sediment. The investigated by-products were: bauxaline®(BX) that is a press-filtered red mud; bauxsol™(BS) that is a press-filtered red mud previously washed with excess of seawater, and gypsum neutralized bauxaline® (GBX). These materials were separately mixed to dredged composted sediment sample considering 5% and 20% sediment: stabilizer ratios. For pilot experiments, rainfall events were regularly simulated for 3 months. Concentrations of As, Mo, Cd, Cr, Zn, Cu, and Ni were analyzed in collected leachates as well as toxicity. Results showed that Cd, Mo, Zn, and Cu were efficiently stabilized in the solid matrix when 20% of BX, BS, and GBX was applied. Consequently, toxicity of leachates was lower than for the untreated sediment, meaning that contaminants mobility was reduced. A 5% GBX was also efficient for Mo, Zn and Cu stabilization. In all scenarios, As stabilization was not improved. Compared to all other monitored elements, Mo mobility seemed to depend upon temperature-humidity conditions during pilot experiments suggesting the need of further investigations

Green technologies for sustainable water management: Introduction and overview

© 2016 American Society of Civil Engineers. This chapter presents the background, current development and future opportunities of green technologies and issues to facilitate strategic planning of sustainable water management systems. It describes the fundamental concepts and current and future applications of green technologies for sustainable improvement in water management. The chapter discusses the appropriate approaches and policies in achieving sustainable objectives and promoting green design and supplies for water utilization. Sustainable water management has received great attention over recent years because of its substantial benefits to the environment, society, and economy. Improvements in water management are likely to come from green technologies fueled by individual curiosity, dedicated effort, and opportunities within a strategic program supported by national and international agencies, universities, and industries. These innovations can significantly contribute to less nonrenewable resource requirement, reduced carbon footprint, greenhouse gas emissions and costs, minimized water losses, and enhanced removal of contaminants

Increased Screen Time Is Associated With Alcohol Desire and Sweetened Foods Consumption During the COVID-19 Pandemic

Background: Elevated screen time has been associated with addictive behaviors, such as alcohol and sugar intake and smoking. Considering the substantial increase in screen time caused by social isolation policies, this study aimed to analyze the association of increased screen time in different devices during the COVID-19 pandemic with consumption and increased desire of alcohol, smoking, and sweetened foods in adults. Methods: A sample of 1,897 adults with a mean age of 37.9 (13.3) years was assessed by an online survey, being composed by 58% of women. Participants were asked whether screen time in television, cell phone, and computer increased during the pandemic, as well as how much time is spent in each device. Closed questions assessed the frequency of alcohol and sweetened food consumption, smoking, and an increased desire to drink and smoke during the pandemic. Educational level, age, sex, feeling of stress, anxiety, depression, and use of a screen device for physical activity were covariates. Binary logistic regression models considered adjustment for covariates and for mutual habits. Results: Increased television time was associated with increased desire to drink (OR = 1.46, 95% CI: 1.12; 1.89) and increased sweetened food consumption (OR = 1.53, 95% CI: 1.18; 1.99), while an increase in computer use was negatively associated with consumption of alcohol (OR = 0.68, 95% CI: 0.53; 0.86) and sweetened foods (OR = 0.78, 95% CI: 0.62; 0.98). Increased cell phone time was associated with increased sweetened food consumption during the pandemic (OR = 1.78, 95% CI: 1.18; 2.67). Participants with increased time in the three devices were less likely to consume sweetened foods for ≥5 days per week (OR = 0.63, 95% CI: 0.39; 0.99) but were twice as likely to have sweetened food consumption increased during pandemic (OR = 2.04, 95% CI: 1.07; 3.88). Conclusion: Increased screen time was differently associated with consumption and desire for alcohol and sweets according to screen devices. Increased time in television and cell phones need to be considered for further investigations of behavioral impairments caused by the pandemic

Physical Activity Is Associated With Improved Eating Habits During the COVID-19 Pandemic

The aim of this study was to analyze the association between physical activity andeating habits during the COVID-19 pandemic among Brazilian adults. A sample of1,929 participants answered an online survey, however 1,874 were included in theanalysis. The impact of the COVID-19 pandemic on eating habits was assessedinquiring about participants’ intake of fruits, vegetables, fried foods, and sweetsduring the pandemic. Physical activity was assessed by asking participants abouttheir weekly frequency, intensity and number of minutes/hours engaging in structuredphysical activities per week. Participants were then stratified into categories based onmoderate-to-vigorous intensity (0–30; 31–90; 91–150; 151–300; and >300 min/week)and into active (≥150 min) or inactive (<150 min). Increased sweets consumption wasthe most commonly reported change to eating habits (42.5%), followed by an increase inthe consumption of vegetables (26.6%), fruits (25.9%), and fried foods (17.9%). Physicalactivity practice was related to lower consumption of fried foods (OR = 0.60; p < 0.001)and sweets (OR = 0.53; p < 0.001). A cluster analysis revealed subjects with higherthe level of physical activity was more likely to follow a healthy diet (p < 0.001). Thus,physical activity was positively associated with healthier eating habits. Health authoritiesmust recommend regular physical as a strategy to improve overall health during theCOVID-19 pandemic. Future studies should address the physical activity interventionsto improve health status during a pandemic

Processing of leather using deep eutectic solvents

Processing of leather has an historical reputation as a chemically and energetically intensive process that produces large volumes of aqueous waste. Saline pollution combined with heavy-metal, dyes and acid and base streams make leather production an ecologically sensitive industry. The current study shows that a variety of deep eutectic solvents (DESs) may be used for the tanning, fatliquoring and dyeing of animal hides, being particularly useful for mineral (chromium) and vegetable tanning processes. The tanning agents are able to penetrate rapidly into the hide, driven by lyotropic swelling due to their high ionic strength. The samples are shown to have similar tanning agent content to the currently used aqueous chromium(III) sulfate solution; however, the waste metal content is shown to be significantly reduced. Incorporation of the DES Ethaline into the leather significantly alters the swelling properties of the leather increasing the flexibility and ductility of the material, therefore acting in the same manner as a fatliquor that lubricates or plasticizes the fibrous structure of the collagen. Ethaline was also used to transport a lysochromic dye throughout the cross section of the leather, and the hydrophobicity of the dye prevents leaching into the aqueous wash solution. Physical measurements show that leather processed using DESs have similar mechanical properties to that processed using conventional aqueous systems