scholarly journals Resistance of a Silicone Membrane to Long-term UV and Moisture Aging in Light of Climate Change

2021 ◽  
Author(s):  
Jean-François Masson ◽  
Peter Collins ◽  
Marzieh Riahinezhad ◽  
Itzel Lopez-Carreon ◽  
Jocelyn Johansen
Keyword(s):  
Climate Change ◽  
Material Characterization ◽  
Room Temperature ◽  
Accelerated Aging ◽  
Building Envelope ◽  
Degradation Mechanisms ◽  
Aging Conditions ◽  
And Storage ◽  
Silicone Membranes

Three room-temperature fluid-applied silicone membranes intended for application in the building envelope were studied in this work. The membranes were subjected to 5000 hours of accelerated UV and moisture aging to evaluate their resistance to long-term aging. The properties of the membranes were studied to understand any degradation mechanisms that might happen during accelerated aging. The weight loss, wetting propensity, cracking and oxidation resistance, and storage modulus were measured at different intervals during the 5000 hours of aging. Based on the material characterization results, the silicone membranes proved to be resilient under aggressive accelerated UV radiation and moisture aging, conditions which can be expected as a result of climate change.

scholarly journals Critical Review of Polymeric Building Envelope Materials: Degradation, Durability and Service Life Prediction

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 299
Author(s):  
Marzieh Riahinezhad ◽  
Madeleine Hallman ◽  
J-F. Masson
Keyword(s):  
Climate Change ◽  
Service Life ◽  
Critical Review ◽  
Life Prediction ◽  
Building Envelope ◽  
Service Life Prediction ◽  
Degradation Mechanisms ◽  
Material Component ◽  
Aging Conditions ◽  
Environmentally Sound

This paper provides a critical review of the degradation, durability and service life prediction (SLP) of polymeric building envelope materials (BEMs), namely, claddings, air/vapour barriers, insulations, sealants, gaskets and fenestration. The rate of material deterioration and properties determine the usefulness of a product; therefore, knowledge of the significant degradation mechanisms in play for BEMs is key to the design of proper SLP methods. SLP seeks to estimate the life expectancy of a material/component exposed to in-service conditions. This topic is especially important with respect to the potential impacts of climate change. The surrounding environment of a building dictates the degradation mechanisms in play, and as climate change progresses, material aging conditions become more unpredictable. This can result in unexpected changes and/or damages to BEMs, and shorter than expected SL. The development of more comprehensive SLP methods is economically and environmentally sound, and it will provide more confidence, comfort and safety to all building users. The goal of this paper is to review the existing literature in order to identify the knowledge gaps and provide suggestions to address these gaps in light of the rapidly evolving climate.

Field temperature and moisture loads from a building envelope as the basis for accelerated aging of barrier membranes

2019 ◽  
Vol 46 (11) ◽  
pp. 969-978 ◽  
Author(s):  
Marzieh Riahinezhad ◽  
Augusta Eve ◽  
Marianne Armstrong ◽  
Peter Collins ◽  
J.-F. Masson
Keyword(s):  
Building Materials ◽  
National Research Council ◽  
Accelerated Aging ◽  
Bimodal Distribution ◽  
Building Envelope ◽  
Rate Of Change ◽  
Single Family ◽  
Field Exposure ◽  
Aging Conditions ◽  
Materials Used

Temperature and relative humidity (RH) data within the building envelope of a single-family home at the National Research Council of Canada’s Canadian Centre for Housing Technology were collected over five years. We report on the distribution, rate of change, and the limits of temperature and moisture variations for south-easting wall and south-facing wall and roof systems to better understand the in-situ environmental conditions to which building materials and components typical of homes in North America may be subjected. Over an average year, wall temperature varied from −25 °C to +45 °C, and temperature followed a bimodal distribution, with maxima at 0 °C to 5 °C and 15 °C to 20 °C. Each maximum represented about 1100 h of field exposure. Roof temperatures, which spanned a temperature range from −35 °C to 75 °C, did not show a Gaussian distribution but were characterized as being multi-modal. From values of temperature and RH, absolute moisture contents within the building envelope were found to range between 1 and 55 g/m3, with the most common values being 6–8 g/m3. The application of this information is discussed and related to the development of realistic accelerated aging conditions to obtain a more accurate durability assessment of building envelope materials used in Canadian dwellings.

scholarly journals Shelf-life of Moroccan prickly pear (Opuntia ficus-indica) and argan (Argania spinosa) oils: a comparative study

2021 ◽  
Vol 72 (1) ◽  
pp. e397
Author(s):  
S. Gharby ◽  
D. Guillaume ◽  
I. Nounah ◽  
H. Harhar ◽  
A. Hajib ◽  
...  
Keyword(s):  
Shelf Life ◽  
Room Temperature ◽  
Seed Oil ◽  
Accelerated Aging ◽  
Ease Of Use ◽  
Preparation Process ◽  
Great Care ◽  
Argan Oil ◽  
Cosmetic Industry ◽  
Aging Conditions

Cactus seed oil is gaining considerable popularity in the cosmetic industry. To estimate cactus seed oil’ industrial as well as domestic ease of use, we investigated the oxidative stability of Moroccan cactus seed oil under accelerated aging conditions. In addition, we compared cactus seed oil stability to that of argan oil, a popular and well-established cosmetic oil, under the same conditions. Cactus seed oil is much more sensitive to oxidation than argan oil. Its shelf-life can be estimated to be no longer than 6 months at room temperature. Such instability means that the preparation process for cactus oil must be carried out with great care and cactus seed oil needs to be protected once extracted.

Long-term Adhesion Studies of Polyimide to Inorganic and Metallic Layers

2012 ◽  
Vol 1466 ◽  
Author(s):  
Juan S. Ordonez ◽  
Christian Boehler ◽  
Martin Schuettler ◽  
Thomas Stieglitz
Keyword(s):  
Silicon Carbide ◽  
Accelerated Aging ◽  
Shear Tests ◽  
Adhesion Promoters ◽  
Intermediate Layers ◽  
Aging Conditions ◽  
Cause Of Failure ◽  
One Year ◽  
Inorganic Layers

ABSTRACTDelamination between thin-film metal and substrate is a major cause of failure in polyimide based neural microelectrode arrays. Chemical adhesion is the only way to establish a long-term bond that will allow two materials to stick to each other even in a wet environment, given that the materials do not deteriorate in the presence of water. This study assesses, by means of peel and shear tests, a long-term quantitative and comparative study of the adhesion of polyimide to various metallic and other inorganic layers of interest. Polyimide (BPDA-PPD) was cured on the layers, which involve platinum, gold and tungsten-titanium as commonly used implant metals and diamond-like carbon (DLC), silicon carbide (SiC), silicon dioxide (SiO2) and silicone nitride (SiN) as potential adhesion promoters to be used later as intermediate layers between metal and polyimide. The adhesion was observed over one year under accelerated-aging conditions by storing the specimens in 60°C saline (corresponding to 40000 hrs at 37°C). Only silicon carbide and amorphous carbon showed almost unaffected adhesion to polyimide over the testing period. No water intrusion at the interface was observed and the strong bond is almost fully maintained.

scholarly journals Long-Term Thermal Aging of Modified Sylgard 184 Formulations

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3125
Author(s):  
Zachary Brounstein ◽  
Jianchao Zhao ◽  
Drew Geller ◽  
Nevin Gupta ◽  
Andrea Labouriau
Keyword(s):  
Material Properties ◽  
High Performance ◽  
Room Temperature ◽  
Microelectromechanical Systems ◽  
Accelerated Aging ◽  
Time Frame ◽  
Gel Point ◽  
Gas Generation ◽  
Gas Products

Primarily used as an encapsulant and soft adhesive, Sylgard 184 is an engineered, high-performance silicone polymer that has applications spanning microfluidics, microelectromechanical systems, mechanobiology, and protecting electronic and non-electronic devices and equipment. Despite its ubiquity, there are improvements to be considered, namely, decreasing its gel point at room temperature, understanding volatile gas products upon aging, and determining how material properties change over its lifespan. In this work, these aspects were investigated by incorporating well-defined compounds (the Ashby–Karstedt catalyst and tetrakis (dimethylsiloxy) silane) into Sylgard 184 to make modified formulations. As a result of these additions, the curing time at room temperature was accelerated, which allowed for Sylgard 184 to be useful within a much shorter time frame. Additionally, long-term thermal accelerated aging was performed on Sylgard 184 and its modifications in order to create predictive lifetime models for its volatile gas generation and material properties.

scholarly journals Durability and Climate Change—Implications for Service Life Prediction and the Maintainability of Buildings

Buildings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 53 ◽  
Author(s):  
Michael A. Lacasse ◽  
Abhishek Gaur ◽  
Travis V. Moore
Keyword(s):  
Climate Change ◽  
Service Life ◽  
Building Materials ◽  
National Research Council ◽  
Building Envelope ◽  
Research Centre ◽  
Climate Resilience ◽  
The Government ◽  
Government Of Canada

Sustainable building practices are rooted in the need for reliable information on the long-term performance of building materials; specifically, the expected service-life of building materials, components, and assemblies. This need is ever more evident given the anticipated effects of climate change on the built environment and the many governmental initiatives world-wide focused on ensuring that structures are not only resilient at their inception but also, can maintain their resilience over the long-term. The Government of Canada has funded an initiative now being completed at the National Research Council of Canada’s (NRC) Construction Research Centre on “Climate Resilience of Buildings and Core Public infrastructure”. The outcomes from this work will help permit integrating climate resilience of buildings into guides and codes for practitioners of building and infrastructure design. In this paper, the impacts of climate change on buildings are discussed and a review of studies on the durability of building envelope materials and elements is provided in consideration of the expected effects of climate change on the longevity and resilience of such products over time. Projected changes in key climate variables affecting the durability of building materials is presented such that specifications for the selection of products given climate change effects can be offered. Implications in regard to the maintainability of buildings when considering the potential effects of climate change on the durability of buildings and its components is also discussed.

scholarly journals Stability of important antibodies for kidney disease: pre-analytic methodological considerations

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5178
Author(s):  
Qiuxia Han ◽  
Songyan Li ◽  
Bo Fu ◽  
Dongwei Liu ◽  
Maoqing Wu ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Room Temperature ◽  
Physical Disturbance ◽  
Serum Samples ◽  
Freeze Thaw ◽  
Long Term Storage ◽  
Circulating Antibodies ◽  
And Storage ◽  
Term Storage

BackgroundThe importance of circulating antibodies as biomarkers of kidney disease has recently been recognized. However, no study has systematically described the methodology of sample preparation and storage regarding antibodies as biomarkers of kidney disease. It remains unknown whether repetitive freeze-thaw cycles, physical disturbances, storage at different temperatures or for different periods of time, or haemolytic or turbid serum samples affect antibody measurements. The aim of this study was to investigate the stabilities of antibodies associated with kidney disease in serum samples under various relevant clinical and research conditions.MethodsWe stored serum samples in the following different conditions: repetitive freeze-thaw cycles (1, 6 or 12 times), long-term storage (7 or 12 months at −80 °C), physical disturbance (1 or 8 h), and storage at 4 °C (1, 3 or 6 weeks) and room temperature (1 or 7 days). The stabilities of the anti-phospholipase A2 receptor (anti-PLA2R), anti-glomerular basement membrane, anti-myeloperoxidase and anti-proteinase 3 antibodies were evaluated with enzyme-linked immunosorbent assays (ELISA).ResultsWe found that repetitive freeze-thaw cycles did not have a significant effect on the stabilities of the abovementioned antibodies in clear serum samples. The ELISA readings of haemolytic and turbid serum samples tended to increase and decrease, respectively. Neither long-term storage at −80 °C nor physical disturbance had a significant effect on anti-PLA2R antibody stability in sealed serum samples. The concentrations of most of these antibodies increased in unsealed serum samples that were stored at 4 °C for more than 6 weeks or at room temperature for more than 7 days.DiscussionOur findings revealed that the abovementioned circulating antibodies that are used as biomarkers for kidney disease had stable physicochemical properties, structures and immunoreactivities such that they were not influenced by repetitive freeze-thaw cycles, physical disturbances or long-term storage at −80 °C. However, the ELISA readings tended to change for haemolytic, turbid and unsealed serum samples.

Human plasma stability during handling and storage: impact on NMR metabolomics

The Analyst ◽  
2014 ◽  
Vol 139 (5) ◽  
pp. 1168-1177 ◽  
Author(s):  
Joana Pinto ◽  
M. Rosário M. Domingues ◽  
Eulália Galhano ◽  
Cristina Pita ◽  
Maria do Céu Almeida ◽  
...  
Keyword(s):  
Human Plasma ◽  
Room Temperature ◽  
Storage Conditions ◽  
Plasma Composition ◽  
Long Term Storage ◽  
Short And Long Term ◽  
The Stability ◽  
And Storage ◽  
Term Storage

The stability of human plasma composition was investigated by NMR, considering different collection tubes, time at room temperature (RT), short- and long-term storage conditions and up to 5 consecutive freeze–thaw cycles.

scholarly journals Investigation of 9000 hours multi-stress aging effects on High-Temperature Vulcanized Silicone Rubber with silica (nano/micro) filler hybrid composite insulator

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253372
Author(s):  
Arooj Rashid ◽  
Jawad Saleem ◽  
Muhammad Amin ◽  
Sahibzada Muhammad Ali ◽  
Aftab Ahmad Khan ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicone Rubber ◽  
Breakdown Strength ◽  
Accelerated Aging ◽  
Environmental Stresses ◽  
Aging Effects ◽  
Nano Silica ◽  
Aging Conditions ◽  
Micro Silica

Degradation in the polymeric insulators is caused due to the environmental stresses. The main aim of this paper is to explore the improved aging characteristics of hybrid samples by adding nano/micro silica in High Temperature Vulcanized Silicone Rubber (HTV-SiR) under long term accelerated aging conditions for 9000 hours. As HTV-SiR is unable to sustain environmental stresses for a long time, thus a long term accelerated aging behavior is an important phenomenon to be considered for field application. The aging characteristics of nano/micro filled HTV-SiR are analyzed by using techniques such as Scanning Electron Microscopy (SEM), Leakage Current (LC), Fourier Transform Infrared Microscopy (FTIR), Hydrophobicity Classification (HC), and breakdown strength for the aging time of 9000 hours. FTIR and leakage currents are measured after every cycle. All the co-filled samples revealed escalated aging characteristics as compared to the neat sample except the SN8 sample (8% nano-silica+20% micro-silica) after 9000 hours of aging. The highest loading of 6% and 8% nano-silica with 20% micro-silica do not contribute to the improved performance when compared with the neat and hybrid samples. However, from the critical experimental analysis, it is deduced that SN2 sample (2% nano-silica+20% micro-silica) is highly resistant to the long term accelerated aging conditions. SN2 has no cracks, lower loss percentages in the important FTIR absorption peaks, higher breakdown strength and superior HC after aging as compared to the unfilled and hybrid samples.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

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