scholarly journals Effects of UV, humidity, and high temperature exposure on linen fibers

2020 ◽  
Author(s):  
Irina Sandulache ◽  
Mihaela-Cristina Lite ◽  
Lucia-Oana Secareanu ◽  
Elena-Cornelia Mitran ◽  
Ovidiu Iordache ◽  
...  
Keyword(s):  
High Temperature ◽  
Color Change ◽  
Chemical Elements ◽  
Environmental Parameters ◽  
Accelerated Weathering ◽  
Textile Materials ◽  
Starting Point ◽  
Accelerated Weathering Test ◽  
Temperature Exposure ◽  
Natural Decay

Generally, the most common damaging factors for linen textile materials are the environmental conditions, their handling, and natural decay. Such environmental factors are ultraviolet (UV) radiation, humidity, and high temperature. Therefore, to investigate the effects these factors may cause, an accelerated weathering test was conducted on linen fabrics, using alternating cycles of UV exposure and humidity, along with relatively high temperatures. The effects of this test were investigated using non-destructive and micro-destructive analysis techniques. Scanning Electron Microscopy (SEM) was used to observe any modifications appearing at the surface of the fibers. Energy Dispersive X-Ray Analysis (EDS) was employed in conjunction with SEM for obtaining the spectrum of the chemical elements that were present at the surface of the linen samples. The modifications of functional groups occurring due to the weathering of linen were assessed by Fourier-Transform Infrared Spectroscopy (FT-IR). The color change of the samples was measured with a spectrophotometer. All the acquired information can be used as a starting point for the development of customized environmental parameters for keeping patrimony linen fabrics in museums in optimum conditions, thus preventing further damage. Additionally, the artificially weathered fabrics will be further employed in conservation experiments as substitute for old linen fabrics.

scholarly journals Wettability and Color Change of Thermally Treated Poplar OSB after Accelerated Weathering Test

2018 ◽  
Author(s):  
Francesco Negro ◽  
Paola Cetera ◽  
Corrado Cremonini ◽  
Luigi Todaro ◽  
Roberto Zanuttini
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Oriented Strand Board ◽  
Accelerated Weathering ◽  
Poplar Wood ◽  
Industrial Coating ◽  
Accelerated Weathering Test ◽  
Coniferous Wood ◽  
Main Components ◽  
Thermally Treated

Oriented strand board (OSB) panels are widely marketed for several applications, from building to packaging. The manufacturing of poplar OSB started recently in Northern Italy representing a relevant innovation in the sector since this product is usually made of coniferous wood. The thermal treatment is widely used for reducing the hygroscopicity of wood-based products, nonetheless it influences the mechanical behavior and degrades the main components of wood, which can affect their finishing. Therefore, it is important to know the properties of the treated surfaces. To this purpose, in this study a lot of OSB panels, made of poplar wood, 15 mm thick and with a density of 590 kg/m3, were thermally treated under vacuum conditions at 190 °C for 2 h and then subjected to accelerated weathering. The changes in color and in wettability due to treatment and accelerated weathering were studied. The thermal treatment determined a significant darkening of the color; the accelerated weathering darkened the untreated surfaces and, on the opposite, lightened the thermo-treated surfaces. The wettability decreased after thermal treatment and increased after weathering, more evidently in treated panels. Overall, this study improves the knowledge about the behavior of the surface of thermo-treated poplar OSB, which is relevant for the industrial coating of this product.

scholarly journals Comparison of the Physico-Mechanical and Weathering Properties of Wood–Plastic Composites Made of Wood Fibers from Discarded Parts of Pomelo Trees and Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2681
Author(s):  
Ke-Chang Hung ◽  
Wen-Chao Chang ◽  
Jin-Wei Xu ◽  
Tung-Lin Wu ◽  
Jyh-Horng Wu
Keyword(s):  
Color Change ◽  
Flexural Modulus ◽  
Modulus Of Rupture ◽  
National Standard ◽  
Accelerated Weathering ◽  
Wood Fibers ◽  
Wood Plastic Composites ◽  
Plastic Composites ◽  
Initial Stage ◽  
Accelerated Weathering Test

The purpose of this study is to compare the characteristics of wood–plastic composites (WPCs) made of polypropylene (PP) and wood fibers (WFs) from discarded stems, branches, and roots of pomelo trees. The results show that the WPCs made of 30–60 mesh WFs from stems have better physical, flexural, and tensile properties than other WPCs. However, the flexural strengths of all WPCs are not only comparable to those of commercial wood–PP composites but also meet the strength requirements of the Chinese National Standard for exterior WPCs. In addition, the color change of WPCs that contained branch WFs was lower than that of WPCs that contained stem or root WFs during the initial stage of the accelerated weathering test, but the surface color parameters of all WPCs were very similar after 500 h of xenon arc accelerated weathering. Scanning electron microscope (SEM) micrographs showed many cracks on the surfaces of WPCs after accelerated weathering for 500 h, but their flexural modulus of rupture (MOR) and modulus of elasticity (MOE) values did not differ significantly during weathering. Thus, all the discarded parts of pomelo trees can be used to manufacture WPCs, and there were no significant differences in their weathering properties during 500 h of xenon arc accelerated weathering.

scholarly journals The effect of using alum mordant in wild cherry bark dyestuff for the production of UV resistant colored paper

2019 ◽  
Vol 70 (4) ◽  
pp. 383-390
Author(s):  
Ayhan Gençer ◽  
Ahmet Can ◽  
Aysun Mustak ◽  
Ülkü Burcu Gitti
Keyword(s):  
Color Change ◽  
Tree Bark ◽  
Thermomechanical Pulp ◽  
Accelerated Weathering ◽  
Wild Cherry ◽  
Cherry Tree ◽  
Accelerated Weathering Test ◽  
Colored Paper ◽  
Environmentally Friendly Method

Depending on the use of wood in the forest industry, wood bark is mostly peeled and used as fuel. The ash and smoke left from the burned bark causes environmental pollution. The most environmentally friendly method for waste disposal is to convert waste into a valuable commodity. In this study, cherry tree bark was used as a dyestuff in paper production. Wild cherry (Cerasus avium L.) bark was boiled with water and KOH. The purpose of using KOH is to increase the solubility of the bark compounds. The chemi-thermomechanical pulp (CTMP) was dyed using the dyestuff. The alum mordant is used to fi x the dyestuff. Paper can be exposed to external influences (mechanical, physical and biological) depending on the place of use. One of these effects is sunshine. When paper is exposed to direct or indirect sunlight, paper changes its color. Depending on the place of use, it is expected that the color of the paper will not be affected by the sunlight or that it will provide long-term strength after the application. Accelerated weathering test was chosen to measure the UV resistance of the dyestuff. The results have shown that the mordant has a significant effect on the fixation of dyestuff. After a total of 150 hours of weathering test, the color change was observed to be the lowest in the paper samples to which alum mordant was added to the dyestuff.

scholarly journals Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation

2021 ◽  
Vol 11 (10) ◽  
pp. 4635
Author(s):  
Marcel Ulrich Ahrens ◽  
Maximilian Loth ◽  
Ignat Tolstorebrov ◽  
Armin Hafner ◽  
Stephan Kabelac ◽  
...  
Keyword(s):  
High Temperature ◽  
Water Absorption ◽  
Industrial Sector ◽  
Heat Pumps ◽  
Working Fluid ◽  
Large Temperature ◽  
Future Trends ◽  
Ammonia Water ◽  
Starting Point ◽  
High Temperature Operation

Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45 °C to 115 °C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

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