EXPERIMENTAL INVESTIGATION OF THE DURABILITY OF LOAD BEARING TIMBER-GLASS COMPOSITES UNDER THE EFFECTS OF ACCELERATED AGING

2019 ◽  
Vol 14 (2) ◽  
pp. 45-59 ◽  
Author(s):  
Halet Almila Arda Buyuktaskin ◽  
Mehmet Serkan Yatagan ◽  
Gulseren Erol Soyoz ◽  
Leyla Tanacan ◽  
Morvarid Dilmaghani
Keyword(s):  
Raw Materials ◽  
Accelerated Aging ◽  
Structural Elements ◽  
Atmospheric Conditions ◽  
Aging Effects ◽  
Glass Composite ◽  
Load Bearing ◽  
Glass Composites ◽  
Before And After

Although timber was used extensively as a structural material for traditional buildings in Turkey in the past, usage of structural timber decreased significantly over time and timber has been largely replaced by other materials. As timber is a natural, durable and sustainable material, it would be desirable to re-introduce timber structural elements to contemporary construction in a form that is appealing to industry. Timber-glass composite structural elements are potentially a good candidate for this purpose. To that end, a series of tests were conducted on load-bearing timber-glass composites in order to understand the long–term structural performance of the composite material under atmospheric conditions; to decrease the recurring cost of repair and maintenance; and to minimize the exhaustion of raw materials and energy. In this paper, the first part of this experimental work is presented, which focuses on the durability of timber-glass composite under the effects of accelerated aging, carried out on small-sized timber-glass composite specimens. Accelerated aging effects were observed under wetting-drying, freezing-thawing, UV effects, resistance to acids and high temperature. The mechanical strength of the timber-glass composite specimens before and after the effect of accelerated aging was measured by adhesion and shear strength tests and a comparative analysis of the results was carried out. The results of the experiments indicate that timber-glass composite is suitable to be used under protection from environmental conditions.

scholarly journals Accelerated Aging Effects on Surface Hardness and Roughness of Lingual Retainer Adhesives

2008 ◽  
Vol 78 (1) ◽  
pp. 140-144 ◽  
Author(s):  
Sabri Ilhan Ramoglu ◽  
Serdar Usumez ◽  
Tamer Buyukyilmaz
Keyword(s):  
Surface Roughness ◽  
Vickers Hardness ◽  
Statistical Significance ◽  
Accelerated Aging ◽  
Aging Effects ◽  
Surface Microhardness ◽  
Halogen Light ◽  
Before And After ◽  
The Mean ◽  
Lingual Retainer

Abstract Objective: To test the null hypothesis that accelerated aging has no effect on the surface microhardness and roughness of two light-cured lingual retainer adhesives. Materials and Methods: Ten samples of light-cured materials, Transbond Lingual Retainer (3M Unitek) and Light Cure Retainer (Reliance) were cured with a halogen light for 40 seconds. Vickers hardness and surface roughness were measured before and after accelerated aging of 300 hours in a weathering tester. Differences between mean values were analyzed for statistical significance using a t-test. The level of statistical significance was set at P < .05. Results: The mean Vickers hardness of Transbond Lingual Retainer was 62.8 ± 3.5 and 79.6 ± 4.9 before and after aging, respectively. The mean Vickers hardness of Light Cure Retainer was 40.3 ± 2.6 and 58.3 ± 4.3 before and after aging, respectively. Differences in both groups were statistically significant (P < .001). Following aging, mean surface roughness was changed from 0.039 μm to 0.121 μm and from 0.021 μm to 0.031 μm for Transbond Lingual Retainer and Light Cure Retainer, respectively. The roughening of Transbond Lingual Retainer with aging was statistically significant (P < .05), while the change in the surface roughness of Light Cure Retainer was not (P > .05). Conclusions: Accelerated aging significantly increased the surface microhardness of both light-cured retainer adhesives tested. It also significantly increased the surface roughness of the Transbond Lingual Retainer.

scholarly journals Improvements of Nano-TiO2 on the Long-Term Chloride Resistance of Concrete with Polymer Coatings

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 323 ◽  
Author(s):  
Guo Li ◽  
Hangyuan Cui ◽  
Jiacheng Zhou ◽  
Weijian Hu
Keyword(s):  
Accelerated Aging ◽  
Polymer Coatings ◽  
Coating Films ◽  
Nano Tio2 ◽  
Modified Polymer ◽  
Chloride Resistance ◽  
Before And After ◽  
Electric Flux ◽  
Ultraviolet Aging

The long-term chloride resistance of concrete treated with nano-TiO2-modified polymer coatings was studied. Three types of organic film-forming paints: polyurethane, epoxy resin, and chlorinated rubber were selected, and concrete specimens with nano-TiO2-modified coatings were fabricated. Then, specimens were subjected to periodical ultraviolet-accelerated aging and subsequent Coulomb electric flux experiments. Nanomodified coatings before and after ultraviolet aging were observed through scanning electron microcopy. Results indicate that the nano-TiO2 particles can effectively reduce the microdefects in coating films and alleviate damages due to aging. As a result, nano-TiO2 can significantly reduce the Coulomb fluxes of coated concrete before and after coating aging, and the average reduction amplitudes reached 66% and 44%. That is, nano-TiO2 can remarkably improve the long-term chloride resistance of coated concrete. In addition, we established the development models of the ultraviolet aging and chloride resistance of coated concrete according to an S-shaped curve.

scholarly journals Prevention of uncontrolled progressive collapse of a high-rise brick building

2018 ◽  
Vol 143 ◽  
pp. 01006
Author(s):  
Oleg Pakhmurin
Keyword(s):  
Climatic Factors ◽  
Progressive Collapse ◽  
Operational Reliability ◽  
Structural Elements ◽  
Load Bearing ◽  
Term Operation ◽  
High Rise ◽  
Failure Diagram ◽  
Stone Walls

In recent years, there is a trend towards increasing the failure rate of buildings and structures as a result of unforeseen situations. This study is aimed at assessing the operational reliability of the structure to prevent emergencies and progressive collapse. The behavior of structures affected by various factors was analyzed. The operational condition of a building with stone walls and a rigid structural frame constructed in the middle of the 20th century was considered. By means of a detailed instrumental examination, effects of long-term operation, climatic factors and violations during construction on the serviceability of the building were analyzed. Geotechnical conditions of the site were investigated. Necessary re-calculations for load-bearing structural elements and foundations were carried out. An expected failure diagram for vertical load-bearing structures of the building is presented. Proposals for preventing progressive collapse were developed on the basis of the author's technique.

Short Term and Long Term Aging Effects of Asphalt Binder Modified with Montmorillonite

2013 ◽  
Vol 594-595 ◽  
pp. 996-1002 ◽  
Author(s):  
Mohd Ezree Abdullah ◽  
Kemas Ahmad Zamhari ◽  
Rosnawati Buhari ◽  
Mohd Nafarizal Nayan ◽  
Hainin Mohd Rosli
Keyword(s):  
Aging Process ◽  
Asphalt Binder ◽  
Mechanical Analysis ◽  
Aging Effects ◽  
Short Term ◽  
Rotational Viscometer ◽  
Before And After ◽  
Pavement Construction ◽  
Modified Binder

Nowadays, most of asphalt used in pavement construction is produced from petrochemicals through refining process of crude oil. When evolves with time, asphalt become stiffer and brittle due aging process. In this paper, the rheological effect of short-term and long-term oxidative ageing of asphalt binder modified with montmorillonite (MMT) was studied using SuperpaveTM rotational viscometer (RV), dynamic shear rheometer (DSR) and Fourier transform infrared (FTIR) instruments. The results indicate the addition of MMT increased the viscosity. Based on dynamic mechanical analysis with DSR, MMT modified binder has a potential to increase rutting and fatigue resistance. In terms of FTIR test, it appears that the chemical bonding had changed in the asphalt binder before and after RTFO and PAV aging which suggest that the additional of MMT could delay the aging process.

Accelerated Aging Effects on Color Stability of Potentially Color Adjusting Resin-based Composites

2021 ◽  
Author(s):  
L Sensi ◽  
C Winkler ◽  
S Geraldeli
Keyword(s):  
Color Change ◽  
Test Chamber ◽  
Accelerated Aging ◽  
Color Stability ◽  
Color Difference ◽  
Composite Resins ◽  
Aging Effects ◽  
Commercial Resin ◽  
Before And After ◽  
Total Color Difference

SUMMARY The aim of this study was to compare the effects of accelerated aging on the overall color stability of potentially color adjusting commercial resin-based composite resins. Thirty specimens (10 mm diameter and 2.5 mm thick; n=6) were fabricated using five different materials: Estelite Omega, GC Kalore, Venus Pearl, Harmonize, and Omnichroma. Color measurements were taken for each sample using a spectrophotometer before and after submitting samples through the artificial aging process (Q-sun Xenon Test Chamber, 102 min light at 63°C black panel temperature; 18 min light and water spray per ASTM G155) for a total of 300 hours (12.5 days). The total color difference (ΔE*ab) was calculated using SpectraMagic NX software and analyzed using one-way analysis of variance and Tukey test. The results for color change (ΔE*ab) were statistically significant. Omnichroma and Venus Pearl presented superior color stability and the lowest overall color change, whereas GC Kalore and Harmonize presented significant color change that would be considered clinically unacceptable (ΔE*ab > 3.3).

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.

Effect of long-term loading on timber load-bearing elements

2015 ◽  
Vol 10 (2) ◽  
pp. 25-34
Author(s):  
Kristian Sogel
Keyword(s):  
Load Bearing

Assessment of Color Stability of Treated Leathers with Silicone Oil and Polyethylene Glycol

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Treatment Process ◽  
Color Change ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Color Stability ◽  
Antioxidant Additive ◽  
Before And After ◽  
Aesthetic Values

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.

NEW VARIETIES OF FRUIT AND BERRIES IN SELECTION OF ALL-RUSSIAN RESEARCH INSTITUTE FOR NATURAL FOOD PRODUCTION

1970 ◽  
pp. 33-37
Author(s):  
N. S. Levgerova ◽  
Е. S. Salina ◽  
I. А. Sidorova
Keyword(s):  
Food Production ◽  
Raw Materials ◽  
Soluble Solids ◽  
Natural Food ◽  
Black Currant ◽  
Central Russia ◽  
Long Term Study ◽  
Apple Cultivars ◽  
Processed Products

The results of the technological assessment of new apple, cherry, black currant, red currant and gooseberry cultivars of VNIISPK breeding for the suitability for the natural food production are given. As a result, the cultivars that are promising for cultivation in raw plantings have been selected. For the production of raw materials in the juice industry, apple cultivars with a high juice yield and content of soluble solids higher than 10.0% were selected: ‘Bolotovskoye’ (Vf), ‘Candil Orlovsky’ (Vf), ‘Osipovskoye’ (3x), ‘Rozhdestvenskoye’ ((Vf + 3x), ‘Zaryanka’ (Vm), ‘Priokskoye’ ((Vf + Co), etc. Based on the long-term study of cultivars for their suitability for compote, jam and jelly, the cultivars that are most suitable for these types of processing are identified. It has been found that taking into account the daily needs of vitamins C and P as the most important antioxidants, all processed products from black currant can serve as their sources, all processed products from cherries, as well as apple juice and gooseberry marmalade can serve as a source of P-active compounds. All columnar apple cultivars as well as ‘Bolotovskoye’, ‘Rozhdestvenskoye’, ‘Veteran’, ‘Imrus’, etc. show high suitability for the production of apple chips. Cherry cultivars ‘Rovesnitsa’, ‘Putinka’, ‘Podarok Uchitelyam’ and ‘Novella’ are suitable for dried fruit. Based on the long-term studies of the technological qualities of the VNIISPK gene pool, a new generation assortment has been formed that has an optimal combination of chemical and technological indicators of fruits that meet modern technological requirements and are suitable for cultivation in the raw plantations of Central Russia.

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