Influence of temperature and different post curing conditions on the mechanical behaviour of polyurethane-based adhesive for civil engineering applications

Sandwich panels based on cold-formed-steel (CFS) face sheets and polyurethane foam (PUR) core were designed and manufactured to be used as a feasible solution for the rehabilitation of degraded floors. This panel is manufactured by a continuous process, whereby the polymerization and foaming of the PUR core is performed simultaneously with the face sheets assembling and their adhesive bonding in certain zones. A three-component polyurethane adhesive, manufactured with the same components as the PUR, is used on the bonding of these steel elements. However, the foaming process of the sandwich panel involves moderate heating at specific stages of its manufacture to enhance polymerization of the PUR, which may influence the adhesive mechanical response. This work intends to establish the best adhesive composition and its thickness to be used on this connection. Additionally, the influence of different curing and post-curing conditions on the shear response of the adhesive is assessed.This work was developed within the scope of the research project “Lightslab – Desenvolvimento de soluções inovadoras de lajes de painel sandwich”, supported by FEDER funds through the Operational Program for Operational Program for Competitiveness and Internationalization (POCI) and the Portuguese National Innovation Agency (ANI) – project no. 33865 [POCI-01-0247- FEDER-033865]. This work was partly 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. The second and fourth authors wish also to acknowledge the grants DFA/BD/07696/2021 and DFA/BD/8319/2020 respectively, provided by Fundação para a Ciência e a Tecnologia, IP (FCT), financed by European Social Fund and national funds through the FCT/MCTES

Physical and mechanical characterization of polyurethane foam core of sandwich panels of various densities

Sandwich foaming is a manufacturing process in which a liquid monomer mixture is injected on the bottom face sheet of the sandwich panel where it polymerizes to form cross-linked polyurethane (PUR) foam providing an adhesive joint between the bottom and upper metal sheets. The single-step process avoids manual operations in the assemblage of the panel and the use of adhesive. However, the PUR foam in the core of the panel and at foam-to-face sheet interface may present fluctuations in the mechanical properties. The aim of this study is the mechanical and thermophysical characterization of PUR foam of various densities produced by sandwich foaming. Additionally, a qualitative assessment of the foam-to-face sheet interface is carried out based on the results of the flatwise tensile and shear tests.This work was developed within the scope of the research project “Lightslab – Desenvolvimento de soluções inovadoras de lajes de painel sandwich”, supported by FEDER funds through the Operational Program for Operational Program for Competitiveness and Internationalization (POCI) and the Portuguese National Innovation Agency (ANI) – project no. 33865 [POCI-01-0247- FEDER-033865]. This work was partly 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. The first and second authors wish also to acknowledge the grants DFA/BD/8319/2020 and DFA/BD/07696/2021 respectively, provided by Fundação para a Ciência e a Tecnologia, IP (FCT), financed by European Social Fund and national funds through the FCT/MCTES

Effect of a weight loss intervention on anthropometric measures and metabolic risk factors in pre- versus postmenopausal women

<p>Abstract</p> <p>Background</p> <p>The present study examines changes in body weight, fat mass, metabolic and hormonal parameters in overweight and obese pre- and postmenopausal women who participated in a weight loss intervention.</p> <p>Methods</p> <p>Seventy-two subjects were included in the analysis of this single arm study (premenopausal: 22 women, age 43.7 ± 6.4 years, BMI 31.0 ± 2.4 kg/m²; postmenopausal: 50 women, age 58.2 ± 5.1 years, BMI 32.9 ± 3.7 kg/m²). Weight reduction was achieved by the use of a meal replacement and fat-reduced diet. In addition, from week 6 to 24 participants attended a guided exercise program. Body composition was analyzed with the Bod Pod^®. Blood pressures were taken at every visit and blood was collected at baseline and closeout of the study to evaluate lipids, insulin, cortisol and leptin levels.</p> <p>Results</p> <p>BMI, fat mass, waist circumference, systolic blood pressure, triglycerides, glucose, leptin and cortisol were higher in the postmenopausal women at baseline.</p> <p>Both groups achieved a substantial and comparable weight loss (pre- vs. postmenopausal: 6.7 ± 4.9 vs 6.7 ± 4.4 kg; n.s.). However, in contrast to premenopausal women, weight loss in postmenopausal women was exclusively due to a reduction of fat mass (-5.3 ± 5.1 vs -6.6 ± 4.1 kg; p < 0.01). In premenopausal women 21% of weight loss was attributed to a reduction in lean body mass.</p> <p>Blood pressure, triglycerides, HDL-cholesterol, and glucose improved significantly only in postmenopausal women whereas total cholesterol and LDL-cholesterol were lowered significantly in both groups.</p> <p>Conclusion</p> <p>Both groups showed comparable weight loss and in postmenopausal women weight loss was associated with a pronounced improvement in metabolic risk factors thereby reducing the prevalence of metabolic syndrome.</p

Action to protect the independence and integrity of global health research

Storeng KT, Abimbola S, Balabanova D, et al. Action to protect the independence and integrity of global health research. BMJ GLOBAL HEALTH. 2019;4(3): e001746

Visitor Flows at a Large-Scale Cultural Event: GPS Tracking at Dutch Design Week

Large-scale cultural events bring many economic, social, and cultural benefits to the hosting cities. Although event producers aim to satisfy the visitors’ needs, they do not usually receive feedback on visitors’ experiences. Moreover, lack of spatial dispersal of visitors might result in less visibility for some activities and locations. An understanding of visitors’ spatial and temporal behavior and the factors influencing visitors’ intra-event destination choices is key to efficient and successful event management and future planning. In this article, we examine the relationship between visitors’ spatial and temporal behavior, the spatial structure of the host city, and visitor characteristics. In order to do this, data are collected from 281 event visitors by means of GPS tracking and paper surveys at the Dutch Design Week (DDW) 2017 event in Eindhoven, the Netherlands. Data are used to understand the area of interest locations, visitor flows, visitor clusters and area of interest choices by applying data processing, network analysis, cluster analysis and bivariate analysis. The results show that one of the three dedicated event areas was considerably less popular by the DDW visitors. Moreover, the choice of intra-event destination locations and areas depended mainly on temporal constraints of the visitors. The findings of this study can inform future event planning and management policies in hosting cities

Control trial of porcine cysticercosis in Uganda using a combination of the TSOL18 vaccination and oxfendazole

BACKGROUND: Neurocysticercosis caused by Taenia solium when the parasite lodges in the central nervous system, is an important cause of human seizures and mortality in sub-Saharan Africa. The parasite is prevalent in many regions of Uganda. Pigs are intermediate hosts for T. solium, and we evaluated a T. solium control program in pigs, involving vaccination of pigs with the TSOL18 vaccine and treatment with oxfendazole. METHODS: The study was conducted in two districts of Eastern Uganda involving the rural village communities of Bukedea (intervention area) and Kumi (control area) during 2016-2017. Seven hundred and thirty-four households were enrolled in the study. Pigs in the intervention area received intramuscular immunizations with TSOL18 (Cysvax™) and an oral medication with 30 mg/kg oxfendazole (Paranthic™) at approximately 3-monthly intervals for 18 months. Porcine cysticercosis was evaluated by post-mortem examination. At the beginning of the study, 111 pigs were examined. In an interim evaluation in the intervention area, 55 pigs were evaluated 12 months after starting the project. At the end of the study approximately 3 months after the final intervention, 55 pigs from the intervention area and 56 pigs from the control area were evaluated. RESULTS: The prevalence of porcine cysticercosis for the two sites was 16.2% at the beginning of the study (17.2% in the intervention area and 15.1% in the control area) with no statistically significant difference (P = 0.759) between the two study sites. Among the 110 animals assessed from the intervention site (55 at the interim evaluation and 55 at the final evaluation), no pig with viable T. solium cysts was found. There was a statistically significant difference between the prevalence at baseline (17.2%) and at the end of the study (0%) in the intervention area (P = 0.001) and a statistically significant difference between the intervention (0%) and control areas (5.4%) (P = 0.041) at the end of the study. CONCLUSIONS: Three-monthly concurrent vaccination of pigs with the TSOL18 vaccine and medication with oxfendazole eliminated T. solium transmission by the animals involved in the study. Application of vaccination with medication in pigs has the potential to reduce transmission of T. solium in Uganda and other endemic countries

A comparative study of urban park preferences in China and the Netherlands

Urban parks play an important role in tackling several urban challenges such as air pollution, urban heat, physical inactivity, social isolation, and stress. In order to fully seize the benefits of urban parks, it is important that they are attractive for various groups of residents. While several studies have investigated residents’ preferences for urban park attributes, most of them have focused on a single geographical context. This study aimed to investigate differences in park preferences, specifically between Dutch and Chinese park users. We collected data in the Netherlands and China using an online stated choice experiment with videos of virtual parks. The data were analyzed with a random parameter mixed logit model to identify differences in preferences for park attributes between Chinese and Dutch citizens, controlling for personal characteristics. Although the results showed a general preference for parks with many trees, several differences were found between the Dutch and Chinese respondents. These differences concerned vegetation (composition of trees and flowers), the presence of benches and play facilities, and could probably be explained by differences in park use, values of nature, and landscape preferences. The findings of this study can be used as design guidelines by urban planners and landscape designers to design attractive and inclusive parks for different target groups