scholarly journals PCL-TiO2 nanocomposite to improve ageing of offset prints

Author(s):  
Tomislav Hudika ◽  
◽  
Tomislav Cigula ◽  
Mihaela Žličarić ◽  
Maja Strižić Jakovljević ◽  
...  

UV radiation or sunlight can affect the printed sample by fading the ink surface and therefore the product losses it's decorative purpose and becomes less desirable to the customer. To create the efficient protective coating, titanium dioxide (TiO2) will be used as a well-known compound that should lower the effects of UV radiation. TiO2 should lower the colour fade after UV radiation and this will be determined by densitometric and colorimetric (CIE L*a*b*) measurements. In addition, measurement of print gloss will also be conducted to evaluate visual appearance of the sample. Biopolymer Polycaprolactone (PCL) was the base of the PCL-TiO2 composite in which TiO2 nano sized. To determine influence of the amount of TiO2, three composites were prepared by adding different weight ratio of the TiO2. The prepared nanocomposites were then applied onto the offset prints on gloss art print paper and on the uncoated paper. The results have shown that TiO2 coating does affect ink’s density, colorimetric properties and print gloss after initial coating. The change in chroma due to the accelerated ageing is most visible on yellow ink, cyan and magenta proved to be the more stable. Accelerated ageing caused change in the L* of black. On all colours, increase of the TiO2 weight ratio improved resistance of colour to change. Coated gloss paper was more resistant to density change where uncoated had lower change in chroma. It could be concluded that TiO2 has the ability to protect the prints in the measured time interval but it has to be noted that concentration of the TiO2 particles also causes colour difference and must be observed when defining composure of the nanocomposite.

2019 ◽  
Vol 106 ◽  
pp. 114-120
Author(s):  
LADISLAV DZURENDA

The effect of UV radiation in Xenotest 450 on the colour of steamed beech wood during the process of simulated ageing .The aim of the paper is to present the changes in colour of steamed beech wood in the pocess of simulated ageing in Xenotest 450. Red-brown colour of beech wood with the coordinates of L* = 62.6 ± 2.8; a* = 10.9 ± 2.3; b* = 17.1 ± 1.3 in the CIE L*a*b* colour space resulted from the mode of colour modification of wood with saturated vapour with the temperature of t = 120 ± 2 oC for τ = 6.5 hours. The surface of samples after drying to the moisture content of w = 12 % and planing was irradiated in Xenotest 450 with xenon gasdischarge tube by UV radiation with the wave length of 340 nm. Accelerated ageing experiment ran in exposure period A1 for seven days. Simulated ageing of thermally treated beech wood showed that due to UV radiation, the wood surface is turning pale and brown. The change in the lightness coordinate by the value of ΔL* = + 6.7 shows the rate of change in the surface lightness and the changes in the values of chromatic coordinates of red colour by the value of Δa* = - 0.1 and yellow colour by Δb* = + 12.3 shows the rate of getting brown. Therefore the hue angle increases from h*ab = 57.5 ° to h°ab = 69.8 °. The value of the total colour difference resulting from the process of ageing is ΔE* = 14.5.


Author(s):  
R. Asmatulu ◽  
K. S. Erukala ◽  
M. M. Rahman

Field of composites is rapidly growing in many industries such as aviation, energy and automotive industries. Composites are known to have a high strength to low weight ratio. Significant improvement in the performance of coatings used in the protection of military and civil aircraft has been achieved the last thirty years. Composite coatings are exposed to many environmental conditions, which can significantly affect their properties. In this research, UV light treatment on the surface of composite was introduced to examine its effects on the adhesion properties between the coating and substrate. A cross-cut test was conducted on the composite panels to assess the adhesion of paint to the substrate after the treatments. Coating performance analyses were also carried out using a Fourier transform infrared spectrometer, water contact angle, and optical microscopic images. The first set of panels was treated with UV radiation for 0, 2, 4 and, 8 days, and the surface wettability was also assessed using the contact angle test. Two coats of paints, including a primer and top coat, were used, and the panels were exposed to UV radiation and immersed in water for 500 hrs and 1000 hrs. It was found that untreated panels showed a much higher contact angle of 106°, whereas the contact angle of panels treated with UV radiation was reduced to 47°. The cross-cut tests showed considerable flaking of the coating along the edges and squares of panels that were not treated, and very small flakes along the edges and parts of the grid square on panels that were UV treated, thus confirming the enhancement of coating adhesion between composite and coating surfaces by UV treatments.


2002 ◽  
Vol 20 (4) ◽  
pp. 559-564
Author(s):  
A. V. Mikhalev ◽  
M. A. Chernigovskaya ◽  
A. Yu. Shalin ◽  
E. S. Kazimirovsky

Abstract. The results of spectral measurements of the daily near-noon surface direct solar ultraviolet radiation in the wavelength range of 295–345 nm obtained in Irkutsk (East Siberia) for the time interval of 1998–2000 are presented. For the period under consideration, the seasonal UV radiation variations are analysed that are associated with the total ozone dynamics, the transition of cyclonic and anticyclonic (Siberian anticyclone) periods, the presence of snow cover, and other factors. The analysis reveals an asymmetric behaviour of the seasonal course in ground-level UV radiation around the time of the summer solstice, with seasonal variation dependence on the wavelength. We have determined the irregular variations of surface UV radiation that is typical for the region, with their properties dependent on the season and on the spectral range analysed. The similarity of the above noted features from year to year was revealed.Key words. Atmospheric composition and structure (Transmission and scattering of radiation; instruments and techniques) – Meteorology and atmospheric dynamics (middle atmosphere dynamics)


Geology ◽  
1987 ◽  
Vol 15 (3) ◽  
pp. 259 ◽  
Author(s):  
Thomas W. Gardner ◽  
David W. Jorgensen ◽  
Christopher Shuman ◽  
Corinne R. Lemieux

2005 ◽  
Vol 72 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Morten D Rasmussen ◽  
Martin Bjerring ◽  
Flemming Skjøth

The objectives of the study were: to evaluate the interaction between visual appearance and California mastitis test (CMT) score of the foremilk in relation to the cell count of the milk; to evaluate the consequences of sorting milk according to these criteria; and to explore whether visual appearance and CMT score of foremilk depended on the time interval between milkings. Measuring somatic cell count (SCC) in composite milk only and discarding milk above certain thresholds will not ensure that milk from all cows with visually abnormal foremilk is withheld from delivery. Low thresholds of SCC will reduce the frequency of cows with abnormal milk but increase the discarding of milk from cows with visually normal foremilk. CMT score of foremilk differentiated better between cows with high and low SCC in composite milk than visual inspection of foremilk. CMT scores of foremilk decreased with increasing interval between milkings within cow, whereas the visual appearance was independent of the interval. We propose that visual appearance of the foremilk should be kept as a criterion for sorting milk at time of milking. For test purposes, the use of visual appearance of foremilk for differentiation between normal and abnormal milk has to be done on multiple milkings. Additionally, CMT scoring of foremilk improves correct classification of normal and abnormal quarters and especially when including data from the previous milking.


1999 ◽  
Vol 121 (3) ◽  
pp. 468-472 ◽  
Author(s):  
Takeo Yoshioka ◽  
Atsushi Korenaga ◽  
Hiroki Mano ◽  
Takashi Yamamoto

We have developed a new method for measuring time intervals of Acoustic Emission (AE) generation for diagnosis of a radial rolling bearing. The method makes the AE signal itself a trigger of the oscillation of the clock pulse and measures the time interval of AE generation by integration of the clock pulses. The measurement device consists of the threshold, clock, time interval measurement and memory circuit, and was applied to rolling contact fatigue experiments. It was confirmed by the experiments that the measured time intervals of AE generation on the inner raceway or the ball agreed with the value calculated based on the kinetics of the rolling bearing. Moreover, we could identify the elements in which a fatigue crack was propagating by the method before the spalling appeared. The identified elements agreed with the failed elements.


2003 ◽  
Vol 125 (6) ◽  
pp. 1058-1066 ◽  
Author(s):  
John D. Wright ◽  
Michael R. Moldover ◽  
Aaron N. Johnson ◽  
Akisato Mizuno

A new pressure, volume, temperature, and time (PVTt) primary gas flow standard for calibrating flowmeters has an expanded uncertainty k=2 of between 0.02% and 0.05%. The standard diverts a steady flow into a collection tank of known volume during a measured time interval. The standard spans the flow range of 1 slm1 to 2000 slm using two collection tanks (34 L and 677 L) and two flow diversion systems. We describe the novel features of the standard and analyze its uncertainty. The thermostatted collection tank allows determination of the average gas temperature to 7 mK (0.0023%) within an equilibration time of 20 min. We developed a mass cancellation procedure that reduced the uncertainty contributions from the inventory volume to 0.017% at the highest flow rate. Flows were independently measured throughout the overlapping flow range of the two systems and they agreed within 0.015 %. The larger collection system was evaluated at high flows by comparing single and double diversions; the maximum difference was 0.0075%.


2013 ◽  
Vol 687 ◽  
pp. 100-106 ◽  
Author(s):  
Valerie Spaeth ◽  
Jean Paul Lecomte ◽  
Marie Paule Delplancke ◽  
Jeanette Orlowsky ◽  
Till Büttner

Impact of the addition of silane and siloxane based hydrophobic powders on cement based mortar was studied. Effect of powder addition on mechanical properties and water absorption of cement based mortar is described. Impact of accelerated ageing, including UV radiation, and rain-sun cycles on hydrophobic performance was assessed, demonstrating excellent durability of silane-based hydrophobic performance.


2021 ◽  
Author(s):  
Ziyuan Chen ◽  
Pengfei Wang ◽  
Mengzhou Zhang ◽  
Shuheng Wen ◽  
Hao Cheng ◽  
...  

Abstract Pulmonary thromboembolism (PTE) is a common cause of sudden unexpected death in forensic practice following deep vein thrombosis (DVT). It remains easy to overlook the special procedure used for the detection of PTE during autopsies; therefore, the relationship between PTE and the associated risk factors is in need of analysis. In the present study, 145 fatal cases of PTE found during autopsies performed from 2004 to 2019 at the Center of Forensic Investigation of China Medical University were retrospectively evaluated; the demographic data, risk factors, original location of DVT, and time interval from the formation of DVT to PTE were analyzed. In addition, the difference in lung-to-heart weight ratio between the PTE and disease-free accident groups was calculated with matching for gender and age. The 40–59 age group accounted for more than half of the total cases (51.03%). Immobilization, trauma or fracture (especially of the pelvis, femur, tibia, or fibula), surgery, pregnancy and cesarean section, mental disorders and the use of antipsychotics were the top 5 high-risk factors for fatal PTE. Among the victims, 92.9% (130/140) died within 60 days of the first exposure to risk factors. Most DVT were formed and shed in lower limb veins, especially popliteal veins and their branches, which caused 87.6% of the thrombi distributed in bilateral pulmonary arteries. No significant difference in the lung-to-heart weight ratio was found between the PTE and control groups. The present study provides valuable information for the prevention and treatment of thrombosis during clinical events and may also be important for alerting forensic examiners to conduct special PTE detection in cases with potential risk factors.


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