Laser and Photogrammetric Modeling of Roads Surface Damages

2021 ◽  
pp. 279-286
Author(s):  
Altynbek Kuduev ◽  
Zhypargul Abdykalyk kyzy ◽  
Boris Shumilov
Keyword(s):  
Surface Damages

Investigation on Surface Grinding of Ti-6Al-4V Using Minimum Quantity Lubrication

2012 ◽  
Vol 500 ◽  
pp. 308-313 ◽  
Author(s):  
Guo Qiang Guo ◽  
Zhi Qiang Liu ◽  
Xiao Hu Zheng ◽  
Ming Chen
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Surface Morphology ◽  
Specific Energy ◽  
Minimum Quantity Lubrication ◽  
Grinding Force ◽  
Dry Grinding ◽  
Surface Damages ◽  
Side Flow ◽  
Mql System

This paper investigates the effects of MQL system on the grinding performance of Ti-6Al-4V using SiC abrasive, the evaluation of the performance consisted of analyzing the grinding force, surface roughness and surface morphology. The experiment result indicated that the favorable lubricating effect of MQL oil makes it has the lowest value of grinding force, specific energy and force raito. MQL has better surface finish than dry grinding and fluid grinding has the lowest value of surface roughness under different grinding depth. Surface damages such as: side flow, plastic deformation, redeposition are present in dry and fluid grinding. As grinding depth increased, the damages become much more severe. But in MQL condition, it gives better surface integrity than dry and fluid grinding.

Surface and Sub-Surface Integrity of Ultra- Machined BK7 Using Fine and Coarse Grained Diamond Wheels

2007 ◽  
Vol 359-360 ◽  
pp. 234-238 ◽  
Author(s):  
Qing Liang Zhao ◽  
Bo Wang ◽  
Ekkard Brinksmeier ◽  
Otmann Riemer ◽  
Kai Rickens ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
High Surface ◽  
Coarse Grained ◽  
Nanometer Scale ◽  
Grinding Wheels ◽  
Fine Grained ◽  
Optical Glasses ◽  
Diamond Grinding ◽  
Surface Damages

This paper aims to evaluate the surface and sub-surface integrity of optical glasses which were correspondingly machined by coarse and fine-grained diamond grinding wheels on Tetraform ‘C’ and Nanotech 500FG. The experimental results show that coarse-grained diamond grinding wheels are capable of ductile grinding of optical glasses with high surface and sub-surface integrity. The surface roughness values are all in nanometer scale and the sub-surface damages are around several micros in depth, which is comparative to those machined by fine-grained diamond wheels.

scholarly journals Influence of Pars Plana Vitrectomy on Ocular Surface using Non-Invasive Keratograph 5M

2018 ◽  
Author(s):  
Lingling Fan ◽  
Lun Liu ◽  
Jian Gao ◽  
Jie Zheng ◽  
Yajing Xu ◽  
...  
Keyword(s):  
Ocular Surface ◽  
Pars Plana Vitrectomy ◽  
Significant Positive Correlation ◽  
Early Stage ◽  
Ocular Surface Disease Index ◽  
Preoperative Level ◽  
Positive Correlation ◽  
Surface Damages ◽  
Pars Plana ◽  
Tear Meniscus Height

Abstract Background: The noninvasive Keratography has been used in evaluating surgery-induced ocular surface changes, while few were known about the influence of pars plana vitrectomy (PPV) on ocular surface. This study aimed to evaluate the influence of PPV on ocular surface using Keratograph 5M. Methods: 30 patients (30 eyes) undergoing primary PPV were recruited in the study. Ocular Surface Disease Index (OSDI) questionnaire was performed. Ocular surface parameters, including tear meniscus height (TMH), noninvasive tear break up time (NITBUT) and bulbar redness score were obtained preoperatively, at 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks postoperatively by Keratograph 5M. Correlations between all the clinical parameters were analyzed further. Results: The percentages of both photophobia and gritty within 4 weeks after PPV were significantly higher than preoperation, while they decreased to the preoperative levels at both 8 weeks and 12 weeks postoperatively. The percentage of sore eyes within 2 weeks postoperatively was significantly higher than preoperation, but there were no significant differences between the percentages of preoperation and 4 weeks, 8 weeks and 12 weeks postoperatively. OSDI score increased significantly within 8 weeks postoperatively, but it returned to the preoperative level at 12 weeks. TMH was increased significantly at the first week after PPV, and recoverd to preoperative level at 2 weeks postoperatively. Both NITBUT-first and NITBUT-average shortened significantly within 8 weeks postoperatively, but they gradually improved to the preoperative levels at 12 weeks. Bulbar redness score was significantly higher than preoperative level within 4 weeks postoperatively, but it returned to the preoperative level at 8 weeks. NITBUT-first and NITBUT-average had a significant positive correlation at each visit. OSDI score had a significant positive correlation with bulbar redness, and TMH had a significant positive correlation with NITBUT-average at both 1 week and 2 weeks postoperatively. Conclusions: Keratograph 5M can provide a reliable noninvasive method to assess the influence of PPV on ocular surface. PPV may cause various changes in both symptoms and signs of ocular surface damages at an early stage, while all these changes will return to preoperative levels gradually at 12 weeks postoperatively.

Removal of Mechanical-Polishing-Induced Surface Damages on 4H-SiC by Chemical Etching and its Effect on Subsequent Epitaxial Growth

2015 ◽  
Vol 821-823 ◽  
pp. 541-544 ◽  
Author(s):  
Yong Zhao Yao ◽  
Yukari Ishikawa ◽  
Yoshihiro Sugawara ◽  
Koji Sato
Keyword(s):  
High Temperature ◽  
Epitaxial Growth ◽  
Chemical Etching ◽  
Flat Surface ◽  
Mechanical Polishing ◽  
Wet Etching ◽  
Surface Damages

To remove the surface damages induced during mechanical polishing (MP) of 4H-SiC, a variety of wet etching recipes and etching conditions were studied. By evaluating the epilayers grown on these etching-treated wafers, it has been found that triangular defects (TRDs) are the main defects originated from the MP-induced damages in these samples. High temperature molten KCl etching at 1100 °C with KOH additive is very effective to remove the damaged surface while keeping a relatively flat surface. Epilayer grown on the KCl+KOH etched wafer showed a TRD density <0.9 cm-2.

Study on the Effects of Abrasive and Coolant-Lubricant Types on Minimum Quantity Lubrication-MQL Grinding

2011 ◽  
Vol 325 ◽  
pp. 231-237 ◽  
Author(s):  
Taghi Tawakoli ◽  
M.J. Hadad ◽  
A. Daneshi ◽  
M.H. Sadeghi ◽  
B. Sadeghi
Keyword(s):  
Surface Quality ◽  
Minimum Quantity Lubrication ◽  
Dry Machining ◽  
Grinding Forces ◽  
Minimum Quantity ◽  
Mql Grinding ◽  
Air Jet ◽  
Dry Grinding ◽  
Surface Damages ◽  
Minimum Quantity Lubricant

In dry grinding, as there is no coolant lubricant to transfer the heat from the contact zone, generation of surface damages are not preventable. Promising alternatives to conventional flood coolant applications are also Minimum Quantity Lubricant (MQL) or Near Dry Machining (NDM) or Semi Dry Machining (SDM). This research has been conducted to study the influence of the abrasive and coolant-lubricant types on the minimum quantity lubrication (MQL) grinding performance. One type of CBN and three types of conventional wheels (corundum) were tested. The tests were carried out in presence of fluid, air jet and eleven types of coolant-lubricants, as well as in dry condition. The results indicate that the finest surface quality and the lowest grinding forces could be obtained when grinding with CBN wheels. In the case of conventional wheels, the coarser wheel induces much proper grinding results.

Post Annealing Etch Process for Improved Reverse Characteristics of 4H-SiC Diode

2009 ◽  
Vol 615-617 ◽  
pp. 663-666
Author(s):  
In Ho Kang ◽  
Wook Bahng ◽  
Sung Jae Joo ◽  
Sang Cheol Kim ◽  
Nam Kyun Kim
Keyword(s):  
Inductively Coupled Plasma ◽  
Schottky Diodes ◽  
Annealing Process ◽  
Activation Process ◽  
Electrical Characteristics ◽  
Inductively Coupled ◽  
Edge Termination ◽  
Post Annealing ◽  
Surface Damages ◽  
Dry Etch

The effects of post annealing etch process on electrical performances of a 4H-SiC Schottky diodes without any edge termination were investigated. The post etch was carried out using various dry the dry etch techniques such as Inductively Coupled Plasma (ICP) and Neutral Beam Etch (NBE) in order to eliminate suspicious surface damages occurring during a high temperature ion activation process. The leakage current of diodes treated by NBE measured at -100V was about one order lower than that of diode without post etch and a half times lower than that of diode treated by ICP without a significant degradation of forward electrical characteristics. Based on the above results, the post annealing process was adapted to a junction barrier Schottky diode with a field limiting ring. The blocking voltages of diode without post annealing etch and diodes treated by ICP and NBE were -1038V, -1125V, and -1595V, respectively.

Analysis of Corrosion Resistance of Heat Exchanger Plates Made of AISI 316L Steel

2020 ◽  
Vol 405 ◽  
pp. 245-250
Author(s):  
Martin Juliš ◽  
Lenka Klakurková ◽  
Pavel Gejdoš
Keyword(s):  
Corrosion Resistance ◽  
Heat Exchanger ◽  
Chemical Composition ◽  
Surface Damage ◽  
Lower Amount ◽  
Aisi 316L ◽  
Velocity Flow ◽  
Close Proximity ◽  
316L Steel ◽  
Surface Damages

For the corrosion resistance analysis of the heat exchanger plates (made of AISI 316L steel) the samples with visible damage was delivered. The major part of the surface damages was located at the place of "close proximity" (or surface contact) of individual plates. Some of delivered samples showed an unequal layers of sediments, which indicating a different flow velocities of operating fluid through the plates. At locations of the upper part of the plates with no sedimentation (high velocity flow), the most surface damage was detected in "near contact" areas as well as outside. On the other hand, the area of the lower part of the plates, where the sediment deposition was massive (lowest velocity flow), was observed the smallest surface damage. The results of the chemical composition analyses showed a lower amount of molybdenum and a higher amount of phosphorus in case of all samples. The contents of the key elements necessary for the corrosion resistance (chromium and nickel) were only just above the lower limit of the prescribed chemical composition interval. For detailed study of surface damage, selected defects were observed and documented using scanning electron microscopy. Localized damage showed intercrystalline failure of material with typical surface morphology degraded as a result of cavitation damage under hydrodynamic stress.

Sign in / Sign up

Export Citation Format

Share Document