Corrosion barriers for silver-based telescope mirrors comparing PEALD and PVD of AlOx

2015 ◽  
Vol 1805 ◽  
Author(s):  
David M. Fryauf ◽  
Andrew C. Phillips ◽  
Nobuhiko P. Kobayashi
Keyword(s):  
Physical Vapor Deposition ◽  
Accelerated Aging ◽  
Atomic Layer ◽  
Chemical Corrosion ◽  
Environmental Testing ◽  
High Reflectivity ◽  
Before And After ◽  
Material Choice ◽  
Telescope Mirrors ◽  
Set Up

ABSTRACTAstronomical telescopes continue to demand high-endurance high-reflectivity silver mirrors that can withstand years of exposure in earth-based observatory environments. The University of California Observatories Astronomical Coatings Lab has undertaken development of protected silver coatings suitable for telescope mirrors that maintain high reflectivity at wavelengths from 340 nm through the mid-infrared spectrum. We present promising results of enhanced corrosion barriers using plasma-enhanced atomic layer deposition (PEALD) of aluminum oxide (AlOx) as a top barrier layer. Novel coating recipes developed with ion-assisted electron beam deposition (IAEBD) of materials including yttrium fluoride and oxides of yttrium, tantalum, and silicon are used to compare the endurance of physical vapor deposition-grown barriers with PEALD-grown barriers of similar thickness. Samples of these mirror coatings were covered with conformal layers of AlOx deposited by PEALD using trimethylaluminum as a metal precursor and plasma-activated oxygen as an oxidant gas. Samples of coating recipes with and without PEALD oxide undergo aggressive high temperature/high humidity (HTHH) environmental testing in which samples are exposed to an environment of 80% humidity at 80°C for ten days in a simple test set-up. HTHH testing show visible results suggesting that the PEALD oxide offers enhanced robust protection against chemical corrosion and moisture from an accelerated aging environment. Mirror samples are further characterized by reflectivity/absorption before and after deposition of oxide coatings. AlOx is suitable for many applications and has been the initial material choice for this study.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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.

Research on pull-type multi-AGV system dynamic path optimization based on time window

2021 ◽  
pp. 095440702098271
Author(s):  
Hongying Shan ◽  
Chuang Wang ◽  
Cungang Zou ◽  
Mengyao Qin
Keyword(s):  
Path Planning ◽  
Time Window ◽  
Planning Problem ◽  
Dijkstra Algorithm ◽  
Before And After ◽  
Common Planning ◽  
Planning Algorithm ◽  
Dynamic Path ◽  
Set Up ◽  
Path Planning Algorithm

This paper is a study of the dynamic path planning problem of the pull-type multiple Automated Guided Vehicle (multi-AGV) complex system. First, based on research status at home and abroad, the conflict types, common planning algorithms, and task scheduling methods of different AGV complex systems are compared and analyzed. After comparing the different algorithms, the Dijkstra algorithm was selected as the path planning algorithm. Secondly, a mathematical model is set up for the shortest path of the total driving path, and a general algorithm for multi-AGV collision-free path planning based on a time window is proposed. After a thorough study of the shortcomings of traditional single-car planning and conflict resolution algorithms, a time window improvement algorithm for the planning path and the solution of the path conflict covariance is established. Experiments on VC++ software showed that the improved algorithm reduces the time of path planning and improves the punctual delivery rate of tasks. Finally, the algorithm is applied to material distribution in the OSIS workshop of a C enterprise company. It can be determined that the method is feasible in the actual production and has a certain application value by the improvement of the data before and after the comparison.

scholarly journals Wear and Friction Characteristics of 65Mn Steel for Spike-Tooth Harrow

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Zhiguo Lu ◽  
Chuanyu Du ◽  
Qingcai Chen ◽  
Tianying Niu ◽  
Na Wang ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Working Environment ◽  
Manganese Steel ◽  
Wear Loss ◽  
Variable Parameters ◽  
Wear Characteristics ◽  
Before And After ◽  
Set Up ◽  
Worn Surface ◽  
Friction And Wear Characteristics

The friction and wear characteristics of spike-tooth material (65Mn steel) of Spike-Tooth Harrow in a two-stage peanut harvester were studied in this paper. The friction and wear tests of pin and disc on 65 manganese steel were carried out on the tribometer, then the wear loss and the friction coefficient were studied. The wear loss of the pin was acquired by calculating the mass of the pin before and after the experiment using an electronic balance. According to the actual working environment of peanut spring-finger, four variable parameters are set up: load, speed, soil moisture and soil type. The friction and wear characteristics of pins were studied under different loads, speeds and different soil environments. After wearing, the worn surface of the material was observed by scanning microscope and the wear mechanism was studied. The experimental results show that the wear of the pin increases with the increase of load and decreases with the increase of rotational speed in the same rotation number. Especially in the case of the sandy soil with 20% in moisture, a maximum wear loss of the pin is achieved.

scholarly journals Innovative passive reinforcements for the gradual stabilization of a landslide according with the observational method

Landslides ◽  
2021 ◽  
Author(s):  
Lorenzo Brezzi ◽  
Alberto Bisson ◽  
Davide Pasa ◽  
Simonetta Cola
Keyword(s):  
Monitoring System ◽  
Low Cost ◽  
Economic Losses ◽  
Fe Model ◽  
Site Conditions ◽  
Observational Method ◽  
Rainy Period ◽  
Sustainable Solutions ◽  
Before And After ◽  
Set Up

AbstractA large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.

Reducing Culture Reporting Errors in the Microbiology Laboratory

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S131-S132
Author(s):  
Kathryn Hogan ◽  
Beena Umar ◽  
Mohamed Alhamar ◽  
Kathleen Callahan ◽  
Linoj Samuel
Keyword(s):  
Real Time ◽  
Error Rate ◽  
Reporting System ◽  
Error Rates ◽  
Tracking Errors ◽  
Corrective Measures ◽  
Safety Awareness ◽  
Before And After ◽  
Set Up ◽  
System Errors

Abstract Objectives There are few papers that characterize types of errors in microbiology laboratories and scant research demonstrating the effects of interventions on microbiology lab errors. This study aims to categorize types of culture reporting errors found in microbiology labs and to document the error rates before and after interventions designed to reduce errors and improve overall laboratory quality. Methods To improve documentation of error incidence, a self-reporting system was changed to an automatic reporting system. Errors were categorized into five types Gram stain (misinterpretations), identification (incorrect analysis), set up labeling (incorrect patient labels), procedures (not followed), and miscellaneous. Error rates were tracked according to technologist, and technologists were given real-time feedback by a manager. Error rates were also monitored in the daily quality meeting and frequently detected errors were discussed at staff meetings. Technologists attended a year-end review with a manager to improve their performance. To maintain these changes, policies were developed to monitor technologist error rate and to define corrective measures. If a certain number of errors per month was reached, technologists were required to undergo retraining by a manager. If a technologist failed to correct any error according to protocol, they were also potentially subject to corrective measures. Results In 2013, we recorded 0.5 errors per 1,000 tests. By 2018, we recorded only 0.1 errors per 1,000 tests, an 80% decrease. The yearly culture volume from 2013 to 2018 increased by 32%, while the yearly error rate went from 0.05% per year to 0.01% per year, a statistically significant decrease (P = .0007). Conclusion This study supports the effectiveness of the changes implemented to decrease errors in culture reporting. By tracking errors in real time and using a standardized process that involved timely follow-up, technologists were educated on error prevention. This practice increased safety awareness in our micro lab.

Frey's syndrome: treatment with botulinum toxin

1997 ◽  
Vol 111 (9) ◽  
pp. 839-844 ◽  
Author(s):  
A. Bjerkhoel ◽  
O. Trobbe
Keyword(s):  
Botulinum Toxin ◽  
Botulinum Toxin A ◽  
Surgical Techniques ◽  
Frey’S Syndrome ◽  
Need For Treatment ◽  
Gustatory Sweating ◽  
Parotid Surgery ◽  
Frey's Syndrome ◽  
Before And After ◽  
Set Up

AbstractFrey's syndrome, i.e. gustatory sweating on the cheek, is a fairly common embarrassment after parotid gland surgery. New surgical techniques have been proposed to avoid this complication, but are not widely in use. Hence, there is need for treatment of Frey's syndrome. All surgical and topical treatments have drawbacks. This study was set up in order to evaluate a recently described treatment. One hundred and two patients were interviewed after parotidectomy. Thirty-one of them had noticed gustatory sweating and 15 patients underwent Minor's starch iodine test before, and after, treatment with intracutaneous injections of botulinum toxin A (Botox®, Allergan Inc., USA). Thirteen of the patients did not experience any gustatory sweating at follow-up (one to 13 months). Minor's starch test showed total disappearance of gustatory sweating in 12 of the 15 treated patients. The only side effect was a discreet, transitory affection of the orbicularis oris muscle in one patient. As this treatment is minimally invasive it could be an attractive treatment for Frey's syndrome if the effect is maintained. Complaints of local hypoaesthesia and pain were also common after parotid surgery.

Conformal Physical Vapor Deposition Assisted by Atomic Layer Deposition and Its Application for Stretchable Conductors

2018 ◽  
Vol 5 (22) ◽  
pp. 1801379 ◽  
Author(s):  
Joong‐Hee Min ◽  
Yi‐An Chen ◽  
I‐Te Chen ◽  
Tianlei Sun ◽  
Dennis T. Lee ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Atomic Layer ◽  
Layer Deposition ◽  
Stretchable Conductors

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.

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