scholarly journals Destruction of protective-decorative coatings for car bodies under the influence of solar radiation

2018 ◽  
Vol 19 (12) ◽  
pp. 474-479
Author(s):  
Danuta Kotnarowska ◽  
Dariusz Stanisławek
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Solar Radiation ◽  
Uv Radiation ◽  
Ageing Time ◽  
Colour Change ◽  
Acrylic Resin ◽  
Time Flow ◽  
Acrylic Coatings

It was stated on the basis of carried out accelerated investigations that UV radiation influence had a significant impact on destruction of acrylic coatings surface layer. The brittleness of surface layer increased with ageing time flow. As a result fillers and pigments particles, losing adhesion to the acrylic resin, issued from the coatings superficial layers which led to coatings thickness as well as gloss decrease. It caused also substantial increase of coatings surface roughness, evaluated on the basis of Ra, Rz and Rt parameters. A deterioration of coatings decorative properties was observed too due to their colour change and local discolorations.

scholarly journals Evaluation of UV radiation influence on abrasivity of protective-decorative coatings for car bodies

2019 ◽  
Vol 24 (6) ◽  
pp. 192-197
Author(s):  
Danuta Kotnarowska ◽  
Dariusz Stanisławek
Keyword(s):  
Surface Roughness ◽  
Mass Loss ◽  
Uv Radiation ◽  
Ageing Time ◽  
Chemical Properties ◽  
Roughness Parameters ◽  
Surface Layers ◽  
Progressive Decline ◽  
Time Flow ◽  
Physico Chemical

The paper presents investigations concerning physico-chemical properties as well as a resistance to abrasion (abrasivity) of three-layer acrylic-polyester (renovation) coating systems after ageing with ultraviolet (UV) radiation. Generated by UV radiation photodestruction and photodegradation of examined coatings surface layers caused their chipping. This had an impact on progressive decline of the coatings thickness and hardness with the ageing time flow. UV ageing caused also almost twofold increase in surface roughness parameters Ra and Rz values. Surface roughness of the aged coatings increasing with the ageing time flow as well as their decreasing hardness contributed to their resistance to abrasion decrease, measured with the mass loss of abraded (using T-07 apparatus) coating material.

scholarly journals Evaluation and Recommendations for Improving the Accuracy of an Inexpensive Water Temperature Logger

2013 ◽  
Vol 30 (7) ◽  
pp. 1576-1582 ◽  
Author(s):  
S. J. Lentz ◽  
J. H. Churchill ◽  
C. Marquette ◽  
J. Smith
Keyword(s):  
Surface Layer ◽  
Solar Radiation ◽  
Water Temperature ◽  
Solar Heating ◽  
Bias Error ◽  
Mean Square ◽  
Temperature Logger ◽  
Accurate Temperature ◽  
Rms Error ◽  
Rms Errors

Abstract Onset's HOBO U22 Water Temp Pros are small, reliable, relatively inexpensive, self-contained temperature loggers that are widely used in studies of oceans, lakes, and streams. An in-house temperature bath calibration of 158 Temp Pros indicated root-mean-square (RMS) errors ranging from 0.01° to 0.14°C, with one value of 0.23°C, consistent with the factory specifications. Application of a quadratic calibration correction substantially reduced the RMS error to less than 0.009°C in all cases. The primary correction was a bias error typically between −0.1° and 0.15°C. Comparison of water temperature measurements from Temp Pros and more accurate temperature loggers during two oceanographic studies indicates that calibrated Temp Pros have an RMS error of ~0.02°C throughout the water column at night and beneath the surface layer influenced by penetrating solar radiation during the day. Larger RMS errors (up to 0.08°C) are observed near the surface during the day due to solar heating of the black Temp Pro housing. Errors due to solar heating are significantly reduced by wrapping the housing with white electrical tape.

The Modification of Carbon Included Polyethylene Surface by Plasma Treatment for Metallizing Using a Low Pressure RF Discharge Plasma

2005 ◽  
Vol 8 (1) ◽  
Author(s):  
Jeou-Long Lee ◽  
Chung-Ming Liu ◽  
Kuen Ting ◽  
Wei-Kung Cheng ◽  
Takayoshi Tsuchida ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Layer ◽  
Discharge Plasma ◽  
Treatment Time ◽  
Low Pressure ◽  
Rf Discharge ◽  
Nickel Layer ◽  
Good Adhesion ◽  
Polyethylene Surface

AbstractSurface modification of the carbon included polyethylene (semi-conductive PE) surface for metallizing using a low pressure RF discharge plasma has been carried out. The contact angle was used as a measure of the wettability of the PE surface. The roughness and the chemical bondings in PE surface layer were analized by DFM and XPS, respectively. Typical results show that the contact angle decreases from approximately 94° to below 10° after several minutes' treatment and recovers to a saturation value when it was put open to the air after treatment. The saturation value of the contact angle is smaller as the gas pressure for treatment is higher and the treatment time is longer but all are below approximately 60° which is still smaller than that of untreated. DFM and XPS results show that the surface roughness and the bondings C-O and C=O in the PE surface layer also increase with increasing the treatment time and seem to be responsible for improving the hydrophilic property of PE. After pretreatment process, nickel was coated on the PE sheet by electrodeposition method and a good adhesion between the nickel layer and the PE surface compared with that of untreated was obtained.

The Effect of Bleach Liquid and Household Cleaner on Surface Hardness and Roughness of Acrylic Base of Orthodontic Appliances

2021 ◽  
Author(s):  
Saeed Noorollahian ◽  
Farinaz Shirban ◽  
Vahid Mojiri
Keyword(s):  
Surface Roughness ◽  
Hydrochloric Acid ◽  
Sodium Hypochlorite ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Liquid Sodium ◽  
P Value ◽  
Orthodontic Appliances ◽  
Acrylic Resins ◽  
Significant Difference

Introduction: The daily use of orthodontic removable plates can interfere with the self-cleansing function of the mouth. Although various techniques have been proposed for cleaning removable orthodontic appliances, there is no consensus on the use of a safe method that preserves the physical properties of the appliance. This study aimed to investigate the effect of using hydrochloric acid (10%, for removal of mineral deposits) and sodium hypochlorite (5.25%, to remove organic matter and discolorations) on surface hardness and roughness of self-cure orthodontic acrylic resins. Materials & Methods: This cross-sectional laboratory study was conducted in the fall of 2017 at Isfahan University of Medical science and Isfahan University of Technology. In this study two orthodontic acrylic resins (Orthocryl® and Acropars®) were used. Eighty samples (12×10×3 mm) from each one were fabricated and divided into four groups (n = 20). Group 1: 15 minutes immersion in household cleaner liquid (Hydrochloric acid, 10%) followed by15 minutes immersion in household bleach liquid (Sodium Hypochlorite, 5.25%). In group 2, immersions were repeated just like group two times and in group 3, were done three times. Group 4 was as control and had no immersion. The surface hardness and roughness of samples were measured. Data were analyzed with Two Way ANOVA and the significance level was set at 0.05. Results: The number of immersion procedures did not significantly affect the surface hardness (p value = 0.958) and surface roughness (p value = 0.657) in the different study groups. There was no significant difference in the surface hardness between the two acrylic resin brands (p value = 0.077); however, Acropars acrylic resin samples exhibited significantly higher surface roughness compared to the Orthocryl acrylic resin samples(p value < 0.001). Conclusion: 15 minutes of immersion in 10% HCl, followed by 15 minutes of immersion in 5.25% NaOCl and repetition of the procedure three times did not significantly affect the surface hardness and roughness of self-cured acrylic resins.

IMMERSION OF HEAT POLYMERIZED ACRYLIC RESIN DENTAL BASE IN ARAK BALI AGAINST SURFACE ROUGHNESS

2021 ◽  
Vol 17 (1) ◽  
pp. 22-26
Author(s):  
Kadek Ayu Wirayuni ◽  
◽  
I Made Hendri Dwi Saputra ◽  
Keyword(s):  
Surface Roughness ◽  
Acrylic Resin ◽  
Control Group ◽  
Surface Strength ◽  
Denture Base ◽  
A Value ◽  
Removable Denture ◽  
Significant Difference ◽  
Post Test ◽  
Oral Tissue

Introduction: The denture base is the part of the removable denture that is supported by good adaptation to the underlying oral tissue. Most of the denture bases are made of acrylic or polymethyl methacrylate resin, better known as PMMA. However, the acrylic resin also has disadvantages such as easily broken and absorbs liquids both water and chemicals. The chemical absorption like alcohol, ethanol, and some drinks that contain acidic materials will chemically be induced with acrylic resin and settle in the pores of the acrylic resin. The chemical damage or defect creates roughness on the surface of the acrylic resin which can cause cracking or crazing and a decrease in surface strength and hardness. Materials and Methods: The method used in this research was a laboratory experimental design with a post-test-only control group using 12 samples consisting of 2 different types of samples by measuring the surface roughness of the acrylic resin after immersing the sample with a predetermined time. Results and Discussions: One-way ANOVA test results showed a significant difference in surface roughness after the samples immersion with a value of p = 0.006 (p <0.05). Conclusions: Based on this research, can be concluded that there is an increase in the surface roughness of the heated polymerized acrylic resin for 3 hours and 4 hours of immersion. The longer the heated polymerized acrylic resin is soaked in arak hence the level of surface roughness increases.

scholarly journals Rated definition of degree of cutter coating influence upon parameters of surface layer quality of parts worked

2017 ◽  
Vol 2 (7) ◽  
pp. 20-24
Author(s):  
Вячеслав Безъязычный ◽  
Vyacheslav Bezyazychnyy ◽  
Максим Басков ◽  
Maksim Baskov
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Residual Stresses ◽  
Layer Surface ◽  
Wear Resistant Coatings ◽  
Cutter Wear ◽  
Definition Of ◽  
Surface Layer Quality ◽  
The Impact

The impact of cutter wear-resistant coatings upon cutting process parameters and characteristics of surface layer quality in the parts worked: residual stresses, a degree and a depth of work hardening of a surface layer, surface roughness is investigated.

scholarly journals Effects of Solar UV Radiation on Morphology and Photosynthesis of Filamentous Cyanobacterium Arthrospira platensis

2005 ◽  
Vol 71 (9) ◽  
pp. 5004-5013 ◽  
Author(s):  
Hongyan Wu ◽  
Kunshan Gao ◽  
Virginia E. Villafañe ◽  
Teruo Watanabe ◽  
E. Walter Helbling
Keyword(s):  
Solar Radiation ◽  
Cell Density ◽  
Uv Radiation ◽  
Time Scales ◽  
Morphological Development ◽  
Filamentous Cyanobacterium ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Adaptive Time ◽  
The Impact

ABSTRACT To study the impact of solar UV radiation (UVR) (280 to 400 nm) on the filamentous cyanobacterium Arthrospira (Spirulina) platensis, we examined the morphological changes and photosynthetic performance using an indoor-grown strain (which had not been exposed to sunlight for decades) and an outdoor-grown strain (which had been grown under sunlight for decades) while they were cultured with three solar radiation treatments: PAB (photosynthetically active radiation [PAR] plus UVR; 280 to 700 nm), PA (PAR plus UV-A; 320 to 700 nm), and P (PAR only; 400 to 700 nm). Solar UVR broke the spiral filaments of A. platensis exposed to full solar radiation in short-term low-cell-density cultures. This breakage was observed after 2 h for the indoor strain but after 4 to 6 h for the outdoor strain. Filament breakage also occurred in the cultures exposed to PAR alone; however, the extent of breakage was less than that observed for filaments exposed to full solar radiation. The spiral filaments broke and compressed when high-cell-density cultures were exposed to full solar radiation during long-term experiments. When UV-B was screened off, the filaments initially broke, but they elongated and became loosely arranged later (i.e., there were fewer spirals per unit of filament length). When UVR was filtered out, the spiral structure hardly broke or became looser. Photosynthetic O2 evolution in the presence of UVR was significantly suppressed in the indoor strain compared to the outdoor strain. UVR-induced inhibition increased with exposure time, and it was significantly lower in the outdoor strain. The concentration of UV-absorbing compounds was low in both strains, and there was no significant change in the amount regardless of the radiation treatment, suggesting that these compounds were not effectively used as protection against solar UVR. Self-shading, on the other hand, produced by compression of the spirals over adaptive time scales, seems to play an important role in protecting this species against deleterious UVR. Our findings suggest that the increase in UV-B irradiance due to ozone depletion not only might affect photosynthesis but also might alter the morphological development of filamentous cyanobacteria during acclimation or over adaptive time scales.

Calculated determination of strength characteristics of assembly joints with tightness taking into account the technological conditions for processing the surfaces

2021 ◽  
pp. 30-34
Author(s):  
V.F. Bezjazychnyi ◽  
M.A. Prokofiev ◽  
F.R. Zhirnova
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Quality Indicators ◽  
Strength Characteristics

The method of calculating the strength of the joint with tension taking into account the technological conditions for processing the mating surfaces, which determine the quality indicators of the surface layer of the material of these surfaces: the surface roughness and the degree of their hardening, was described.

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