accelerated ageing
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2022 ◽  
Vol 14 (2) ◽  
pp. 980
Author(s):  
Roberto Landolfi ◽  
Maurizio Nicolella

The External Thermal Insulation Composite System (ETICS) is a common cladding technology that is widely used thanks to its well-known advantages. Despite previous studies dealing with ETICS durability in real-building case studies or involving accelerated ageing tests in climatic chambers, little progress has been made in the knowledge of the long-term durability of the system. In order to realize optimized maintenance plans for this component, the durability of the whole system, and of the most-used insulating materials for the ETICS (i.e., cork, polyurethane, rock wool, glass wool, grey EPS, and fiberfill wood), has been investigated. Based on previous experiments on ageing cycles, different climatic chambers were used to accelerate performance decay by simulating natural outdoor exposure in order to assess different physical and thermal characteristics (thermal transmittance, decrement factor, time shift, water absorption, thermal resistance, and conductivity). Recorded trends show that materials with lower thermal conductivity exhibit lower performance decay, and vice versa. The durability of the ETICS with different insulating materials (as the only variable in the different samples) was evaluated in order to quantify service life and then correctly plan maintenance interventions. Life-cycle assessment must take into account service life and durability for each material of the system. A higher durability of insulating materials allows for the execution of less maintenance interventions, with the loss of less performance over time. This study shows the physical and thermal behavior of the ETICS during its service life, comparing the differences induced by the most-used insulating materials. As a result of accelerated ageing cycles, the analyzed ETICS reveals a low grade of decay and measured performances show little degradation; for thermal conductivity, differences between the measured and the declared conductivities by technical datasheet were observed.


Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 70
Author(s):  
Katarzyna Ciacka ◽  
Marcin Tyminski ◽  
Agnieszka Gniazdowska ◽  
Urszula Krasuska

Seed ageing is associated with a high concentration of reactive oxygen species (ROS). Apple (Malus domestica Borkh.) seeds belong to the orthodox type. Due to a deep dormancy, they may be stored in dry condition at 5 °C for a long time, without viability loss. In the laboratory, artificial ageing of apple seeds is performed by imbibition in wet sand at warm temperature (33 °C). The aim of the work was to study nitric oxide (NO) as a seed vigour preservation agent. Embryos isolated from apple seeds subjected to accelerated ageing for 7, 14, 21 or 40 days were fumigated with NO. Embryo quality was estimated by TTC and MDA tests. ROS level was confirmed by NBT staining. We analysed the alteration in transcript levels of CAT, SOD and POX. NO fumigation of embryos of seeds aged for 21 days stimulated germination and increased ROS level which correlated to the elevated expression of RBOH. The increased total antioxidant capacity after NO fumigation was accompanied by the increased transcript levels of genes encoding enzymatic antioxidants, that could protect against ROS overaccumulation. Moreover, post-aged NO application diminished the nitro-oxidative modification of RNA, proving NO action as a remedy in oxidative remodelling after seeds ageing.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 141
Author(s):  
Ismail Alj ◽  
Marc Quiertant ◽  
Aghiad Khadour ◽  
Quentin Grando ◽  
Karim Benzarti

The present study investigates the environmental durability of a distributed optical fiber sensing (DOFS) cable on the market, commonly used for distributed strain measurements in reinforced concrete structures. An extensive experimental program was conducted on different types of specimens (including samples of bare DOFS cable and plain concrete specimens instrumented with this DOFS cable) that were exposed to accelerated and natural ageing (NA) conditions for different periods of up to 18 months. The instrumentation of both concrete specimens consisted of DOFS cables embedded at the center of the specimens and bonded at the concrete surface, as these two configurations are commonly deployed in the field. In these configurations, the alkalinity of the surrounding cement medium and the outdoor conditions are the main factors potentially affecting the characteristics of the DOFS component materials and the integrity of the various interfaces, and hence impacting the strain transfer process between the host structure and the core optical fiber (OF). Therefore, immersion in an alkaline solution at an elevated temperature or freeze/thaw (F/T) and immersion/drying (I/D) cycles were chosen as accelerated ageing conditions, depending on the considered configuration. Mechanical characterizations by tensile and pull-out tests were then carried out on the exposed specimens to assess the evolution of the mechanical properties of individual component materials as well as the evolution of bond properties at various interfaces (internal interfaces of the DOFS cable, and interface between the cable and the host structure) during ageing. Complementary physico-chemical characterizations were also performed to better understand the underlying degradation processes. The experimental results highlight that immersion in the alkaline solution induced a significant and rapid decrease in the bond properties at internal interfaces of the DOFS cable and at the cable/concrete interface (in the case of the embedded cable configuration), which was assigned to chemical degradation at the surface of the cable coating in contact with the solution (hydrolysis and thermal degradation of the EVA copolymer component). Meanwhile, F/T and I/D cycles showed more limited effects on the mechanical properties of the component materials and interfaces in the case of the bonded cable configuration. A comparison with the same specimens exposed to outdoor NA suggested that the chosen accelerated ageing conditions may not be totally representative of actual service conditions, but provided indications for improving the ageing protocols in future research. In the last part, an analysis of the distributed strain profiles collected during pull-out tests on instrumented concrete specimens clearly illustrated the consequences of ageing processes on the strain response of the DOFS cable.


2021 ◽  
Vol 13 (4) ◽  
pp. 10738
Author(s):  
Babafemi S. OLISA ◽  
Femi E. AWOSANMI ◽  
Michael S. AKINROPO ◽  
Philip O. OJO ◽  
Khalid ISHIAK ◽  
...  

Hybrids and open pollinated varieties (OPVs) are two commercial maize seed types cultivated in Nigeria. Information on their response to mechanical damage during processing is limited. This study is thus aimed at assessing the response of hybrids and OPVs of maize seeds to mechanical damage which would facilitate fabrication of processing facilities suitable for either of the maize types. Six maize varieties: three hybids (‘New Kaduna’, ‘SDM-1’, and ‘JO-195’) and three OPVs (‘Sammaz 15’, ‘Sammaz 27’ and ‘Suwan-1-stry’) were used for the study. The seed samples were subjected to standard germination, seedling vigour analysis, accelerated ageing, conductivity and fast green tests. The result showed that all the hybrid seed varieties had more damaged seeds than their OPVs counterpart. Shoot length and root length were more affected than other parts of the seedling. There were differences in the magnitude of electrolyte leakage as well as in what time each seed type (hybrid or OPVs) passed through the phases with ‘JO-195’ having the highest rate of electrolyte leakage. Hybrid seeds had lower resistance to mechanical damage and poorer storability when compared with the OPVs. In the overall, for all the traits, ‘Sammaz 15’, the best among OPVs was more promising when compared with ‘SDM-1’ which was the best among hybrid varieties. Processing machine equipment and accessories that are suitable for hybrid seeds might be inappropriate for conditioning OPVs.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7580
Author(s):  
Emil Sasimowski ◽  
Łukasz Majewski ◽  
Marta Grochowicz

The results of comprehensive studies on accelerated (artificial) ageing and biodegradation of polymer biocomposites on PBS matrix filled with raw wheat bran (WB) are presented in this paper. These polymer biocomposites are intended for the manufacture of goods, in particular disposable packaging and disposable utensils, which decompose naturally under the influence of biological agents. The effects of wheat bran content within the range of 10–50 wt.% and extruder screw speed of 50–200 min−1 during the production of biocomposite pellets on the resistance of the products to physical, chemical, and biological factors were evaluated. The research included the determination of the effect of artificial ageing on the changes of structural and thermal properties by infrared spectra (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). They showed structural changes—disruption of chains within the ester bond, which occurred in the composition with 50% bran content as early as after 250 h of accelerated ageing. An increase in the degree of crystallinity with ageing was also found to be as high as 48% in the composition with 10% bran content. The temperature taken at the beginning of weight loss of the compositions studied was also lowered, even by 30 °C at the highest bran content. The changes of mechanical properties of biocomposite samples were also investigated. These include: hardness, surface roughness, transverse shrinkage, weight loss, and optical properties: colour and gloss. The ageing hardness of the biocomposite increased by up to 12%, and the surface roughness (Ra) increased by as much as 2.4 µm at the highest bran content. It was also found that ageing causes significant colour changes of the biocomposition (ΔE = 7.8 already at 10% bran content), and that the ageing-induced weight loss of the biocomposition of 0.31–0.59% is lower than that of the samples produced from PBS alone (1.06%). On the other hand, the transverse shrinkage of moldings as a result of ageing turned out to be relatively small, at 0.05%–0.35%. The chemical resistance of biocomposites to NaOH and HCl as well as absorption of polar and non-polar liquids (oil and water) were also determined. Biodegradation studies were carried out under controlled conditions in compost and weight loss of the tested compositions was determined. The weight of samples made from PBS alone after 70 days of composting decreased only by 4.5%, while the biocomposition with 10% bran content decreased by 15.1%, and with 50% bran, by as much as 68.3%. The measurements carried out showed a significant influence of the content of the applied lignocellulosic fillers (LCF) in the form of raw wheat bran (WB) on the examined properties of the biocompositions and the course of their artificial ageing and biodegradation. Within the range under study, the screw speed of the extruder during the production of biocomposite pellets did not show any significant influence on most of the studied properties of the injection mouldings produced from it.


Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1943
Author(s):  
Stacy Deshaies ◽  
Luca Garcia ◽  
Frédéric Veran ◽  
Laetitia Mouls ◽  
Cédric Saucier ◽  
...  

In order to obtain information on the oxidative behavior of red wines, oxygen consumption rates and electrochemical changes (cyclic voltammetry) were measured for nine red wines subject to three different accelerated ageing tests: chemical (with hydrogen peroxide), enzymatic (with laccase from Trametes versicolor), and temperature (at 60 °C). Oxidative behavior depended both on the wine sample and accelerated ageing test type. A good correlation was observed between electrochemical parameters of charges for reference/non-oxidized wines, in accordance with their antioxidant capacity, and the variation of charges after enzymatic and temperature tests, meaning that cyclic voltammetry could be used in order to predict these two oxidation tests and reflect the wine sensitivity towards respective oxidation targets. However, it was not possible to predict wine chemical oxidation test based on hydrogen peroxide from the electrochemical measurements.


OENO One ◽  
2021 ◽  
Vol 55 (4) ◽  
pp. 181-195
Author(s):  
Marie Denat ◽  
Dolores Pérez ◽  
José María Heras ◽  
María Pilar Sáenz-Navajas ◽  
Vicente Ferreira

This study aimed at determining the changes induced by two S. cerevisiae strains, (IONYS wf™ and Lalvin ICV D254™) on the sensory and chemical aroma profiles of Tempranillo wine, after fermentation and after ageing. The 64 aroma molecules determined were grouped attending to sensory and chemical similarity into 17 aroma vectors. Sensory studies included a sorting task and a descriptive analysis by flash profile with a trained panel. Results revealed that, even if ageing is the dominant factor, the strain of yeast introduces significant and consistent differences, both in sensory and aroma vector profiles (11 out of 17 affected). Wines made with D254 contained higher levels of ethyl esters, acetic acid, cinnamates and ethyl acetate and lower levels of linear fatty acids, β-damascenone, acetaldehyde, higher alcohols and lactones than those made with IONYS. The first profile was related to black and fresh fruit notes, while the second to white and compote fruits.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Laura A. Bardon ◽  
Clare A. Corish ◽  
Meabh Lane ◽  
Maria Gabriella Bizzaro ◽  
Katherine Loayza Villarroel ◽  
...  

Abstract Background Malnutrition negatively impacts on health, quality of life and disease outcomes in older adults. The reported factors associated with, and determinants of malnutrition, are inconsistent between studies. These factors may vary according to differences in rate of ageing. This review critically examines the evidence for the most frequently reported sociodemographic factors and determinants of malnutrition and identifies differences according to rates of ageing. Methods A systematic search of the PubMed Central and Embase databases was conducted in April 2019 to identify papers on ageing and poor nutritional status. Numerous factors were identified, including factors from demographic, food intake, lifestyle, social, physical functioning, psychological and disease-related domains. Where possible, community-dwelling populations assessed within the included studies (N = 68) were categorised according to their ageing rate: ‘successful’, ‘usual’ or ‘accelerated’. Results Low education level and unmarried status appear to be more frequently associated with malnutrition within the successful ageing category. Indicators of declining mobility and function are associated with malnutrition and increase in severity across the ageing categories. Falls and hospitalisation are associated with malnutrition irrespective of rate of ageing. Factors associated with malnutrition from the food intake, social and disease-related domains increase in severity in the accelerated ageing category. Having a cognitive impairment appears to be a determinant of malnutrition in successfully ageing populations whilst dementia is reported to be associated with malnutrition within usual and accelerated ageing populations. Conclusions This review summarises the factors associated with malnutrition and malnutrition risk reported in community-dwelling older adults focusing on differences identified according to rate of ageing. As the rate of ageing speeds up, an increasing number of factors are reported within the food intake, social and disease-related domains; these factors increase in severity in the accelerated ageing category. Knowledge of the specific factors and determinants associated with malnutrition according to older adults’ ageing rate could contribute to the identification and prevention of malnutrition. As most studies included in this review were cross-sectional, longitudinal studies and meta-analyses comprehensively assessing potential contributory factors are required to establish the true determinants of malnutrition.


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