Surface rehabilitation of Portland cement concrete (PCC) pavements using single or double surface dressings with soft bitumen, conventional or modified emulsions

Surface dressings are a sustainable maintenance alternative for pavements with surface distresses, due to the low amount of resources involved. This paper aims to analyze the viability of using twelve different surface dressing solutions, including three binders (conventional and modified emulsions, and a soft 160/220 bitumen) and a covering with diluted emulsion, for surface treatment of Portland cement concrete (PCC) pavements. Several test methods were used to evaluate the macrotexture, skid resistance, adhesion, and resistance to wearing on a large scale prototype. In general, single surface dressings increased further the macrotexture of the concrete pavement surface. The skid resistance of single and double surface dressings was similar. The best surface dressing in the pull-off test was that with the 160/220 bitumen. The conventional and modified emulsions presented similar mechanical adhesion in the Vialit plate test. Concerning the prototype wearing test, the best result was obtained for the double surface dressing with bitumen covered with diluted emulsion. Based on this work’s results, the surface dressings are a potential surface rehabilitation alternative for concrete pavements.This work was partially financed by FCT / MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020. This work is financed by national funds through FCT - Foundation for Science and Technology, under grant agreement SFRH/BD/137421/2018 attributed to the 1st author

Coaxial fibres incorporated with phase change materials for thermoregulation applications

Nowadays, the growing concern about improving thermal comfort in different structures (textiles, buildings, and pavements, among others) has stimulated research into phase change materials (PCMs). The direct incorporation of PCMs into composite materials can cause mechanical impacts. Therefore, this study focuses on the design of phase change coaxial fibres (PCFs), using commercial cellulose acetate (CA) or recycled CA obtained from cotton fabrics (CAt) as the sheath and polyethylene glycol (PEG) 2000 as the core, via the wet spinning method; the fibres vary in molecular weight, concentration and ejection velocity. The fibres were assessed for their optical, chemical, thermal, and mechanical properties. The presence of PEG2000 is confirmed in the core of the fibres. Thermal analyses revealed a mass loss at high temperatures, attributable to the presence of PEG2000. Notably, the fibres with CA (Mn 30,000) showed superior thermal and mechanical performance. The melting point of PEG2000 incorporated into these PCFs coincided with the melting point of pure PEG2000 (about 55 °C), with a slight deviation, indicating that PCFs were obtained. Finally, the results point to the application of the fibres in civil engineering materials requiring a phase change between 50 and 60 °C, providing promising prospects for their use in applications requiring thermoregulatory properties.This research was funded by the Portuguese Foundation for Science and Technology (FCT) under the projects MicroCoolPav EXPL/EQUEQU/1110/2021 and NanoAir PTDC/FISMAC/6606/2020 (https://doi.org/10.54499/PTDC/FIS-MAC/6606/2020) and within the framework of Strategic Funding UIDB/04650/2020, UIDB/04029/2020 (https://doi.org/10.54499/UIDB/04029/2020) and UID/QUI/0686/2020. I.R.S. and H.P.F. would like to thank FCT for their funding contracts 2022.00763.CEECIND (https://doi.org/10.54499/2022.00763.CEECIND/CP1718/CT0006) and 2021.02720.CEECIND (https://doi.org/10.54499/DL57/2016/CP1377/CT0098)

Photocatalytic performance of textiles coated with TiO2-RGO system for degradation of crude petroleum under similar solar irradiation

The pollution caused by oil and its toxic derivatives presents a considerable risk to the public health and the environment. Here, we studied the influence of TiO2 nanoparticles immobilized on three types of textiles materials (Cotton, Entretela and PLA) coated with reduced graphene oxide (RGO) to be used for degradation of crude petroleum under simulated solar irradiation. The morphological studies of the functionalized textiles substrates were performed by using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, which indicated an excellent dispersion and adhesion of nanoparticles on the textile fibres covered with RGO. Ultraviolet–visible Diffuse Reflectance spectra suggests a reduction in the band gap energy of TiO2 due to the presence of RGO. The excitation/emission Synchronized Fluorescence and Fourier transform Infrared spectroscopies demonstrated that the functionalized textiles substrates exhibit a great potential for photocatalytic degradation of organic compounds with high prospects in petroleum and wastewater treatment areas

Effects of dietary palm oil supplementation on ruminal degradation and apparent digestibility of nutrients in sheep

Abstract The aim of this study was to evaluate the effects of the inclusion of palm oil on the ruminal environment and nutrient digestibility of sheep diets. Twenty rumen-cannulated sheep were kept in individual stalls equipped with feeding and drinking troughs The animals were fed five diets based on Elephant grass (Pennisetum purpureum Schum. cv. Roxo) silage and supplemented with 0, 25, 50, 75, or 100 g kg-1 of palm oil (based on total DM). The Elephant grass was harvested at 90 days of regrowth and the concentrate was based on ground corn grain, soybean meal and mineral mix (20 g kg-1 DM), offered to the sheep at a ratio of 1.5 g kg-1d-1 of body weight (restricted intake) to maintain a forage-to-concentrate ratio of 1:1, based on DM. There were no differences (P = 0.324) in ruminal disappearance and degradability parameters with up to 75 g of oil per kg of DM. Organic matter showed a linear reduction in apparent digestibility, while ether extract increased linearly. Palm oil affected the digestibility and nutritional parameters in ruminant diets

Prevention of hypertension in patients with pre-hypertension: protocol for the PREVER-prevention trial

<p>Abstract</p> <p>Background</p> <p>Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage.</p> <p>Methods</p> <p>This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution.</p> <p>Discussion</p> <p>The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.</p> <p>Trial Registration</p> <p>Clinical Trials <a href="http://www.clinicaltrials.gov/ct2/show/NCT00970931">NCT00970931</a>.</p