PRACTICAL USE OF THE SURFACE LAYERS OF LASER MODIFIED WC-Cu COATINGS

Tribologia ◽  
2016 ◽  
Vol 270 (6) ◽  
pp. 121-130
Author(s):  
Izabela PLISZKA ◽  
Norbert RADEK ◽  
Aneta GĄDEK-MOSZCZAK ◽  
Peter FABIAN
Keyword(s):  
Carbon Steel ◽  
Laser Treatment ◽  
Laser Processing ◽  
Resistance Test ◽  
Test Results ◽  
Mechanical Seals ◽  
Surface Layers ◽  
Friction Resistance ◽  
Before And After ◽  
Wear Coatings

The article presents the study of the effect of laser treatment on the microhardness of WC-Cu coatings applied by electro spark deposition. Observations of friction resistance test results allowed the evaluation of the coatings after laser treatment. The studies were conducted using WC-Cu electrodes, produced by sintering of nanostructural powders. The anti-wear coatings were electro-spark deposited over C45 carbon steel by means of EIL-8A, while the laser processing was performed by electro coats applied using a Nd:YAG, BLS720. Model tests were carried on test mechanical seals for rings made of SiC and WC-Cu coatings before and after laser treatment.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

scholarly journals Ex vivo evaluation of a multilayered sealant patch for watertight dural closure: cranial and spinal models

2021 ◽  
Vol 32 (8) ◽  
Author(s):  
A. Kinaci ◽  
S. van Thoor ◽  
S. Redegeld ◽  
M. Tooren ◽  
T. P. C. van Doormaal
Keyword(s):  
Ex Vivo ◽  
Resistance Test ◽  
Burst Pressure ◽  
Cerebrospinal Fluid Leakage ◽  
Computer Assisted ◽  
Dural Defect ◽  
Test Results ◽  
Physiological Conditions ◽  
Dural Attachment ◽  
The Mean

AbstractCerebrospinal fluid leakage is a frequent complication after cranial and spinal surgery. To prevent this complication and seal the dura watertight, we developed Liqoseal, a dural sealant patch comprising a watertight polyesterurethane layer and an adhesive layer consisting of poly(DL-lactide-co-ε-caprolactone) copolymer and multiarmed N-hydroxylsuccinimide functionalized polyethylene glycol. We compared acute burst pressure and resistance to physiological conditions for 72 h of Liqoseal, Adherus, Duraseal, Tachosil, and Tisseel using computer-assisted models and fresh porcine dura. The mean acute burst pressure of Liqoseal in the cranial model (145 ± 39 mmHg) was higher than that of Adherus (87 ± 47 mmHg), Duraseal (51 ± 42 mmHg) and Tachosil (71 ± 16 mmHg). Under physiological conditions, cranial model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment during 72 hours as opposed to 3 of 3 for Adherus and Duraseal and 0 of 3 for Tachosil. The mean burst pressure of Liqoseal in the spinal model (233 ± 81 mmHg) was higher than that of Tachosil (123 ± 63 mmHg) and Tisseel (23 ± 16 mmHg). Under physiological conditions, spinal model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment for 72 hours as opposed to 3 of 3 for Adherus and 0 of 3 for Duraseal and Tachosil. This novel study showed that Liqoseal is capable of achieving a strong watertight seal over a dural defect in ex vivo models.

scholarly journals Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Barbara Helena Barcaro Machado ◽  
Ivy Dantas De Melo E. Silva ◽  
Walter Marou Pautrat ◽  
James Frame ◽  
Mohammad Najlah
Keyword(s):  
Laser Treatment ◽  
Three Dimensional ◽  
Skin Surface ◽  
Clinical Scale ◽  
3D Images ◽  
Laser Resurfacing ◽  
Before And After ◽  
Measuring Outcomes ◽  
Skin Scar ◽  
Scientific Validation

AbstractMeasuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

scholarly journals An Empirical Study on the Application of Cooperative Learning to Comprehensive English Classes in a Chinese Independent College

2017 ◽  
Vol 10 (2) ◽  
pp. 94
Author(s):  
Ji Meng
Keyword(s):  
Cooperative Learning ◽  
Empirical Study ◽  
Test Results ◽  
Independent College ◽  
Language Competence ◽  
English Classes ◽  
Academic Level ◽  
Before And After ◽  
Posttest Questionnaire ◽  
Positive Impacts

This research investigated a comparison between the effect of cooperative learning and lecture teaching on Comprehensive English classes in a Chinese Independent College. An empirical study for two semesters was carried out in the forms of pretest, posttest, questionnaire and interviews. While control class was taught in the conventional way, experiment class was instructed based on cooperative base groups with positive interdependence structured on purpose. Compared with traditional instructions, cooperative learning as pedagogy can improve students’ performance on course exams, but not necessarily their language competence as shown in national English competency tests taken before and after the experiement. Test results also indicate students from experiment class who excelled in competency test outnumbered those from control class, revealing that cooperative learning has positive impacts especially on students at a relatively higher academic level. Questionaire results show that students are most inclined to agree they have more chances to practice the language in a cooperative environment.

Mössbauer study of surface layers of high-speed steel after laser treatment

1992 ◽  
Vol 69 (1-4) ◽  
pp. 589-592 ◽  
Author(s):  
R. Valiev ◽  
V. Bochkov ◽  
Sh. Bashkirov ◽  
E. Romanov ◽  
V. Chistjakov
Keyword(s):  
Laser Treatment ◽  
High Speed ◽  
High Speed Steel ◽  
Surface Layers ◽  
Mössbauer Study

Investigation on Material Selection in Missan Oilfields Similar Environment

2014 ◽  
Vol 641-642 ◽  
pp. 427-433
Author(s):  
Shuang Cheng ◽  
Feng Lin ◽  
Pei Long Yang ◽  
Pei Ke Zhu ◽  
Jin Gen Deng ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Nickel Alloy ◽  
Martensitic Stainless Steel ◽  
Material Selection ◽  
Pressure Ratio ◽  
Service Condition ◽  
Corrosion Mechanism ◽  
Test Results ◽  
Chrome Steel

This paper analyzed the corrosion environment of Missan oilfields and investigated the oilfield country tubular goods used in other similar oilfields. Summarized the effect of partial pressure ratio of H2S/CO2 and Cl-to the corrosion behavior of OCTG. This paper concluded the service condition, test results and anti-corrosion mechanism of carbon steel, low-chrome steel, modified martensitic stainless steel and nickel alloy. Finally arrived at conclusion that the nickel alloy can meet the requirement of Missan oilfields, some literature reported that the modified martensitic stainless steel can apply in H2S/CO2 environment. In the condition that be easy to replace the tubular, carbon steel and low-chrome steel tubular can meet the requirement with corrosion inhibitor.

Characteristics of Phenomena in Powders Type RE2Zr2O7-Al2O3 in High Temperature Annealing Conditions

2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala
Keyword(s):  
High Temperature ◽  
Perovskite Oxide ◽  
Differential Scanning Calorimetric ◽  
Test Results ◽  
Dsc Analysis ◽  
Annealing Conditions ◽  
Before And After ◽  
Influence Of Temperature On ◽  
Dta Analysis ◽  
Type Bond

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.

Properties of the Electro-Spark Deposited Coatings - Technology and Applications

2015 ◽  
Vol 818 ◽  
pp. 61-64 ◽  
Author(s):  
Norbert Radek ◽  
Jozef Bronček ◽  
Peter Fabian ◽  
Jacek Pietraszek ◽  
Krzysztof Antoszewski
Keyword(s):  
Wear Resistance ◽  
Powder Metallurgy ◽  
Carbon Steel ◽  
Abrasive Wear ◽  
Hot Pressing ◽  
Abrasive Wear Resistance ◽  
Roughness Analysis ◽  
Ceramic Electrodes ◽  
Machine Parts ◽  
Wear Coatings

The paper is concerned with the performance properties of electro-spark deposited coatings, which were determined basing on microstructural and roughness analysis and application tests. The studies were conducted using of the tungsten carbide-ceramic electrodes produced by the powder metallurgy hot pressing route. The anti-wear coatings were electro-spark deposited over C45 carbon steel by means of an EIL-8A. These coatings are likely to be applied to increase the abrasive wear resistance of tools and machine parts.

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