High-Temperature Ageing of Modern Polymer-Coated Optical Fibres

1998 ◽  
Vol 531 ◽  
Author(s):  
P. Mauron ◽  
Ph. M. Nellen ◽  
U. Sennhauser
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Ageing Time ◽  
Telecommunication Networks ◽  
Accelerated Ageing ◽  
Optical Fibres ◽  
Fibre Fracture ◽  
Sensor Applications ◽  
Temperature Ageing ◽  
Short Time

AbstractReliability and durability are essential for optical fibres in both telecommunication networks and sensor applications. We report on stress-free accelerated ageing of modem telecommunication fibres in a temperature range from 60 °C to 150 °;C in dry air, relative humidity (rh) up to 85 %, and deionised water. Fibre fracture stress was measured by dynamic tensile testing according to IEC 60793-1-3 standard requirements. Ambient humidity effects on fibre fracture strength are shown. High temperature and relative humidity ageing behaviour of fibres and acrylate coatings is discussed. Fibre fracture strengths were fitted as functions of ageing time and ageing temperature using single process Arrhenius-based models. Acceleration factors can differ by several orders of magnitude, depending on the activation energy of the process. High temperatures damage acrylate coatings, which might deteriorate its adhesion to the fibre, thus introducing new ageing mechanisms not experienced under service conditions. Nevertheless, short time ageing at high temperature is useful for estimating relative lifetime of different products and for optimizing production process.

scholarly journals Effects of Double-Ageing Heat Treatments on the Microstructure and Mechanical Behaviour of a Ti-3.5Al-5Mo-4V Alloy

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 209
Author(s):  
Xuanming Ji ◽  
Panpan Ge ◽  
Song Xiang ◽  
Yuanbiao Tan
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Low Temperature ◽  
Mechanical Behaviour ◽  
Ageing Time ◽  
Two Stage ◽  
Ageing Treatment ◽  
Ω Phase ◽  
Α Phase ◽  
Temperature Ageing

In this work, the effect of double-ageing heat treatments on the microstructural evolution and mechanical behaviour of a metastable β-titanium Ti-3.5Al-5Mo-4V alloy is investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-ageing treatments are composed of low-temperature pre-ageing and high-temperature ageing, where the low-temperature pre-ageing is conducted at 300 °C or 350 °C for different times, and the high-temperature ageing is conducted at 500 °C for 8 h. The results show that the phase transformation sequence is altered with the time spent during the first ageing stage, the isothermal ω phase is precipitated in the pre-ageing process of the alloy at 300 °C and 350 °C with the change in the ageing time, and the ω phase is finally transformed into the α phase with the extension of pre-ageing time. The existence time of the ω phase is shortened as the pre-ageing temperature increases. The microhardness of the alloy increases with increasing pre-ageing time and temperature. Compared with single-stage ageing, the ω phase formed in the pre-ageing stage changes the response to subsequent high-temperature ageing. After the two-stage ageing treatment, the precipitation size of the α phase is obviously refined after the double-ageing treatment. A microhardness test shows that the microhardness of the two-stage aged alloy increases with extended pre-ageing time.

Ti-679

Alloy Digest ◽  
1966 ◽  
Vol 15 (11) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Creep Strength ◽  
Heat Treating ◽  
High Temperature Alloy ◽  
Temperature Performance ◽  
Time Strength ◽  
Short Time

Abstract Ti-679 is a titanium high temperature alloy having an excellent combination of short-time strength, creep strength and stability to 900 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ti-48. Producer or source: Titanium Metals Corporation of America.

PRINTING. The ageing resistance of offset and electrophotographic prints

2012 ◽  
Vol 27 (4) ◽  
pp. 739-749
Author(s):  
Silva Grilj ◽  
Tadeja Muck ◽  
Diana Gregor-Svetec
Keyword(s):  
Relative Humidity ◽  
Surface Coating ◽  
Accelerated Ageing ◽  
Colour Stability ◽  
Light Fastness ◽  
Moist Heat ◽  
Printing Technique ◽  
Lower Light ◽  
Recycled Fibres ◽  
2D And 3D

Abstract The moist heat (80°C and 65% relative humidity) and light (xenon arc lamp) treatments of accelerated ageing were applied to investigate the colour stability of offset and electrophotographic prints on papers made of virgin and I 00% recycled fibres. The prints were evaluated using spectrophotometric measurements and additional colour differences calculations. In addition to the colour differences, the 2D and 3D colour gamuts are presented. The results reveal the different colour stability of prints. The effect depends on the type of accelerated ageing, printing technique, composition of ink and paper characteristics. Moist heat ageing has less influence on colour stability than light ageing. The electrophotographic prints show better ageing resistance than offset prints. The intluence of ink on print light fastness is considerable. Azo pigments in magenta and yellow have lower light fastness than phthalocyanine pigments in cyan or carbon black. The surface coating has an intluence on light fastness of prints. Meanwhile, prints on recycled papers show similar colour stability compared to prints on papers made of virgin fibres

scholarly journals Differential impact of Holder and High Temperature Short Time pasteurization on the dynamic in vitro digestion of human milk in a preterm newborn model

2020 ◽  
Vol 328 ◽  
pp. 127126 ◽  
Author(s):  
Stefano Nebbia ◽  
Marzia Giribaldi ◽  
Laura Cavallarin ◽  
Enrico Bertino ◽  
Alessandra Coscia ◽  
...  
Keyword(s):  
High Temperature ◽  
Human Milk ◽  
In Vitro Digestion ◽  
Preterm Newborn ◽  
Differential Impact ◽  
High Temperature Short Time ◽  
Short Time

scholarly journals High-Temperature Short-Time and Holder Pasteurization of Donor Milk: Impact on Milk Composition

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Diana Escuder-Vieco ◽  
Juan M. Rodríguez ◽  
Irene Espinosa-Martos ◽  
Nieves Corzo ◽  
Antonia Montilla ◽  
...  
Keyword(s):  
High Temperature ◽  
Human Milk ◽  
Milk Composition ◽  
Donor Human Milk ◽  
High Temperature Short Time ◽  
Lactose Concentration ◽  
C 30 ◽  
Milk Banks ◽  
Short Time

Holder pasteurization (HoP; 62.5 °C, 30 min) is commonly used to ensure the microbiological safety of donor human milk (DHM) but diminishes its nutritional properties. A high-temperature short-time (HTST) system was designed as an alternative for human milk banks. The objective of this study was to evaluate the effect of this HTST system on different nutrients and the bile salt stimulated lipase (BSSL) activity of DHM. DHM was processed in the HTST system and by standard HoP. Macronutrients were measured with a mid-infrared analyzer. Lactose, glucose, myo-inositol, vitamins and lipids were assayed using chromatographic techniques. BSSL activity was determined using a kit. The duration of HTST treatment had a greater influence on the nutrient composition of DHM than did the tested temperature. The lactose concentration and the percentage of phospholipids and PUFAs were higher in HTST-treated than in raw DHM, while the fat concentration and the percentage of monoacylglycerides and SFAs were lower. Other nutrients did not change after HTST processing. The retained BSSL activity was higher after short HTST treatment than that following HoP. Overall, HTST treatment resulted in better preservation of the nutritional quality of DHM than HoP because relevant thermosensitive components (phospholipids, PUFAs, and BSSL) were less affected.

Influence of Guar Gum on the Thermal Stability of Listeria innocua, Listeria monocytogenes, and γ-Glutamyl Transpeptidase during High-Temperature Short-Time Pasteurization of Bovine Milk

1999 ◽  
Vol 62 (8) ◽  
pp. 861-866 ◽  
Author(s):  
PUNIDADAS PIYASENA ◽  
ROBIN C. McKELLAR
Keyword(s):  
High Temperature ◽  
Laminar Flow ◽  
Protective Effect ◽  
Guar Gum ◽  
Listeria Innocua ◽  
Water Mixture ◽  
High Temperature Short Time ◽  
Whole Milk ◽  
Short Time ◽  
Glutamyl Transpeptidase

Mathematical models describing the thermal inactivation of γ-glutamyl transpeptidase (TP) and Listeria innocua in milk during high-temperature short-time (HTST) pasteurization were validated with data from TP, L. innocua, and L. monocytogenes trials in guar gum–milk. Holding tube times were determined for turbulent flow using water, and for laminar flow using a guar gum (0.27% wt/wt)–sucrose (5.3% wt/wt)–water mixture. Inactivation of TP and L. innocua was lower in a solution of guar gum (0.25% wt/wt) in whole milk than was predicted by models derived from studies with whole milk alone. Use of laminar flow timings improved model fit but did not completely account for the observed protective effect. L. monocytogenes survival was close to that predicted by the L. innocua model, although some protection was afforded this pathogen under laminar flow. Considerable intertrial variability was noted for L. monocytogenes. Risk analysis simulations using @RISK, a Lotus 1-2–3W add-in, were used to account for intertrial variability. Simulated log10 %reductions consistently underpredicted experimental L. monocytogenes survival (fail-safe), thus the L. innocua model derived in milk is suitable for estimating L. monocytogenes survival in viscous products. Increased thermal tolerance during laminar flow may be attributed to the protective effect of stabilizer.

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