The Implications of Energetic and Kinetic Surface Instability for a Stress Measurement Technique

1999 ◽  
Vol 594 ◽  
Author(s):  
H. H. Yu ◽  
Z. Suo
Keyword(s):  
Activation Energy ◽  
Stress State ◽  
Measurement Technique ◽  
Elastic Energy ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Surface Profile ◽  
Surface Instability ◽  
Before And After ◽  
Stress Dependent

AbstractIt has been understood for some time that elastic energy can cause surface roughening during a solid surface motion. This instability has recently led to a novel experimental technique to determine stress state on the surface of a solid by measuring the surface profile before and after etching [1]. Along a separate line of investigation, Aziz and co-workers has recently described a different kind of instability, also driven by stress [2]. Their experiments showed that the activation energy of the surface mobility depends linearly on the stress state, and this dependence can cause surface instability. The two kinds of instabilities have very different characteristics. In this paper, we describe a linear stability analysis of a three dimensional interface evolving under stress. The interface can be destabilized either by stress-dependent activation energy or by elastic energy. The implications for the stress measurement technique are discussed. It is suggested that the same experimental procedure be used to measure surface energy and activation strains.

Surface profile of different heat-treated nickel-titanium files before and after root canal preparation

2021 ◽  
Vol 32 (6) ◽  
pp. 8-15
Author(s):  
Iandara de Lima Scardini ◽  
Denise Maria Zezell ◽  
Juliana Lisboa Couto Marques ◽  
Laila Gonzales Freire ◽  
Marcelo dos Santos
Keyword(s):  
Three Dimensional ◽  
Surface Profile ◽  
Surface Wear ◽  
Significance Level ◽  
Root Canals ◽  
Heat Treated ◽  
Before And After ◽  
Surface Irregularities ◽  
Multiple Uses ◽  
Surface Changes

Abstract The aim of this study was to evaluate surface wear, presence of microcracks and surface irregularities of WaveOne (WO) and WaveOne Gold (WOG) instruments before and after multiple uses. Eight Primary instruments of the WO and WOG systems were evaluated, each one was used to prepare six mesial canals of extracted human mandibular molars. The surface of the instruments was evaluated before use (T0), after instrumentation of three (T1) and six (T2) root canals. Surface wear was analyzed using a three-dimensional optical profiler and the presence of microcracks and surface irregularities were evaluated using a tabletop scanning electron microscopy. The Friedman test was used to assess surface wear and Kruskal-Wallis test to evaluate the presence of microcracks and surface irregularities, with a 5% significance level. There was a significant increase in wear in both groups at T2, compared to T0 (p=0.0003). The surface wear after instrumentation of six canals (T2-T0) was statistically greater in the WOG group, than in the WO group (p=0.02), where the presence of microcracks was significantly greater and increased after multiple uses (p<0.05). The presence of surface irregularities in the cutting blade before and after use was statistically greater in the WOG group than WO group (p<0.05). Wear of the cutting blade, microcracks and surface irregularities were observed on the surface topography of all the instruments after multiple uses. These surface changes may affect the cutting efficiency of WOG files and increase the risk of fracture of WO files.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

scholarly journals A Repeatable and Reproducible Digital Method to Quantify the Cement Excess and Enamel Loss after Debonding Lingual Multibracket Appliance Therapy

2021 ◽  
Vol 11 (3) ◽  
pp. 1295
Author(s):  
Alba Belanche Monterde ◽  
Alberto Albaladejo Martínez ◽  
Alfonso Alvarado Lorenzo ◽  
Adrián Curto ◽  
Jorge Alonso Pérez-Barquero ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Measurement Method ◽  
Dental Arch ◽  
Micro Computed Tomography ◽  
Morphometric Measurement ◽  
Before And After ◽  
Repeatability And Reproducibility ◽  
Lingual Brackets ◽  
Multibracket Appliance ◽  
Area And Volume

The aim of the present study is to present a repeatable, reproductible, and accurate morphometric measurement method for measuring and quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances. Ten conventional lingual brackets were cemented in 10 extracted teeth embedded into an epoxy resin model simulating a dental arch. This model was scanned before and after bonding the lingual brackets, after debonding, and after polishing the surfaces. We also performed a Micro-Computed Tomography scan of the lingual brackets used. Afterward, the standard tessellation language (STL) digital file was aligned, each tooth was segmented individually, and the file was re-aligned using engineer morphometry software. Inter-operator and intra-operator comparative analyses were performed using the ANOVA test, and the repeatability and reproducibility of the morphometric measurement technique were analyzed using Gage R&R statistical analysis. Repeatability showed 0.07% and 0.16% variability associated with the area and volume measures, respectively, while reproducibility showed 0.00% variability associated with the area and volume measures, respectively. In conclusion, the morphometric measurement technique is a repeatable, reproductible, and accurate morphometric measurement method for quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances.

scholarly journals Three-dimensional analysis of the root canal preparation with Reciproc Blue®, WaveOne Gold® and XP EndoShaper®: a new method in vivo

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Javier Caviedes-Bucheli ◽  
Nestor Rios-Osorio ◽  
Diana Usme ◽  
Cristian Jimenez ◽  
Adriana Pinzon ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Root Canal ◽  
Paired Comparison ◽  
Three Dimensional ◽  
New Method ◽  
Root Canal Preparation ◽  
Paired Data ◽  
Before And After ◽  
Student’S T

Abstract Background The purpose of this study was to evaluate the changes in canal volume after root canal preparation in vivo with 3 different single-file techniques (Reciproc-Blue®, WaveOne-Gold® and XP-EndoShaper®), with a new method using CBCT and 3D reconstruction. Methods In this prospective study, thirty human lower premolars from healthy patients were used, in which extraction was indicated for orthodontic reasons. All the teeth used were caries- and restoration-free with complete root development, without signs of periodontal disease or traumatic occlusion, and with only one straight canal (up to 25º curvature). Teeth were randomly divided into three different groups: Reciproc-Blue, WaveOne-Gold and XP-EndoShaper. CBCT scans before root canal preparation were used to create a 3D reconstruction with RHINOCEROS 5.0 software to assess the initial canal volume, and then compared with 3D reconstructions after canal preparation to measure the increase in canal volume. Student’s t test for paired data were used to determine statistically significant differences between the before and after canal volumes. Anova test was used to determine statistically significant differences in the percentage of canal volume increase between the groups and Tukey's post-hoc test were used to paired comparison. Results Reciproc-Blue showed the higher increase in canal volume, followed by WaveOne-Gold and XP-EndoShaper (p = 0.003). XP-EndoShaper did not show a statistically significant increase in canal volume after root canal preparation (p = 0.06). Conclusion With this model, Reciproc-Blue showed higher increase in root canal volume, followed by WaveOne-Gold, while XP-EndoShaper did not significantly increase root canal volume during preparation.

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.

Three-dimensional changes in root angulation of buccal versus palatal maxillary impacted canines after orthodontic traction: A retrospective before and after study

2021 ◽  
Author(s):  
Yalil Augusto Rodríguez-Cárdenas ◽  
Luis Ernesto Arriola-Guillén ◽  
Aron Aliaga-Del Castillo ◽  
Gustavo Armando Ruíz-Mora ◽  
Guilherme Janson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Changes ◽  
Impacted Canines ◽  
Before And After ◽  
Before And After Study

An Acoustic System for Pipeline Profile Measurement

1983 ◽  
Vol 105 (4) ◽  
pp. 475-479
Author(s):  
H. Van Calcar
Keyword(s):  
Measurement Technique ◽  
Measurement System ◽  
Performance Enhancement ◽  
Three Dimensional ◽  
Profile Measurement ◽  
Baseline Measurement ◽  
Acoustic System ◽  
Position Measurement ◽  
Long Baseline ◽  
Hardware Configuration

This paper presents an acoustic position measurement system used for precise three-dimensional flowline profile measurement. The system measures several points along the flowline using the long-baseline measurement technique and augments this measurement with depth telemetry repeaters to maintain elevation accuracy throughout the changing installation geometry. The paper discusses both the measurement system and the performance enhancement features. The paper concludes with a discussion of the hardware configuration and the accuracy that can be expected when the technique is extended into deeper operating areas.

Weight-Reduction Optimization Design for Milling Planer Bed Based on Finite Element Analysis

2012 ◽  
Vol 490-495 ◽  
pp. 2785-2789
Author(s):  
Dong Sun ◽  
Xu Dong Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Weight Reduction ◽  
Optimization Design ◽  
Weak Link ◽  
Three Dimensional ◽  
Production Costs ◽  
Element Analysis ◽  
Before And After ◽  
Improvement Scheme

The milling planer bed is one of the most important foundational parts for the entire machine, sufficient stiffness is required. The posterior segment of a certain milling planer bed is regarded as the optimization object in this paper. Three-dimensional modeling method is used to calculate the exact weight of the bed and then finite element analysis is used to research the static and dynamic characteristics before and after weight-reduction. The weak link of the bed is found out and a improvement scheme is put forward ensuring lower production costs under the premise of sufficient rigidity.

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