scholarly journals Surface Roughness of Auto Polymerized Acrylic Resin According to Different Manipulation and Polishing Methods

2008 ◽  
Vol 78 (5) ◽  
pp. 931-934 ◽  
Author(s):  
Tatiana Siqueira Gonçalves ◽  
Ana Maria Spohr ◽  
Rodrigo Matos de Souza ◽  
Luciane Macedo de Menezes
Keyword(s):  
Surface Roughness ◽  
Acrylic Resin ◽  
Mechanical Polishing ◽  
Average Surface Roughness ◽  
Average Surface ◽  
Paired Samples ◽  
Student’S T ◽  
Mechanical Mass ◽  
Student’S T Test

Abstract Objective: To test the hypothesis that no differences exists in the in situ level of surface roughness of an auto polymerized acrylic resin irrespective of the method of manipulation and polishing. Materials and Methods: Forty volunteers received the test specimens. Surface roughness was evaluated using a rugosimeter. Samples of auto polymerized acrylic resin were submitted to two methods of manipulation—mass and addition—as well as to two types of polishing—mechanical and chemical. Four test groups were designated according to manipulation and polishing techniques: mass-mechanical, mass-chemical, addition-mechanical, and addition-chemical. Five measures of surface roughness were taken from each sample and average surface roughness (Ra) was determined before and 20 days after the samples were worn by the volunteers. The data obtained were analyzed by the Student's t-test for paired samples as well as by analysis of variance. Results: Significant differences in Ra were found between mechanical and chemical polishing. Surface roughness was not influenced by manipulation techniques. Mechanical polishing presented the lowest values of Ra. There was a significant increase in surface roughness after volunteers wore the specimens for 20 days. Conclusions: The hypothesis is rejected. There were differences on the surface roughness according to the different methods of manipulation and polishing used, but high values of surface roughness were found for all groups. Mechanical polishing showed the lowest values of surface roughness and thus should be preferred.

Development of TSV Reveal Process Using Very Fine Si/Cu Grinding and Metal Contamination Removal

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 001928-001955
Author(s):  
Naoya Watanabe ◽  
Masahiro Aoyagi ◽  
Daisuke Katagawa ◽  
Tsubasa Bandoh ◽  
Takahiko Mitsui ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Chemical Mechanical Polishing ◽  
Metal Contamination ◽  
Mechanical Polishing ◽  
Grinding Wheel ◽  
Average Surface Roughness ◽  
Average Surface ◽  
3D Ics ◽  
Cu Contamination ◽  
Contamination Removal

Three-dimensional integrated circuits (3D-ICs) using through silicon via (TSV) have been developed as an emerging technology that can lead to significant progress (1–4). Among various TSV processes, the via-middle process has potential for wide spread use because formation of small-sized TSVs is relatively easy in the via-middle process. However, TSV reveal process must be performed for electrical contact in the via-middle process. This TSV reveal process is important because it can influence the metal contamination and stacking yield of 3D-ICs. Conventionally, TSV reveal is performed by Si grinding and Si dry etching (5). A disadvantage of that method is the resultant TSV depth deviation, which can cause bonding failure during wafer/chip stacking. In (6), TSV leveling was performed by introducing a chemical mechanical polishing (CMP) step after deposition of the backside insulator. However, the revealed TSVs break during CMP step if they exceed a certain height. To overcome these problems, we developed a novel TSV reveal process comprising direct Si/Cu grinding and metal contamination removal (7,8). First, simultaneous grinding of Cu and Si was performed using a novel vitrified grinding wheel. In situ cleaning with a high-pressure micro jet and the inelastic porous structure of the grinding wheel suppressed the adhesion of Cu contaminants to the Si, and TSVs were leveled and exposed. Next, an electroless Ni-B film was deposited on the Cu surface of the TSVs. The Si was etched with an alkaline solution, whereas the Cu was protected by the Ni-B film. An insulator was deposited, and then the insulator on the top surface of the TSV was removed. We achieved the backside reveal of TSVs without TSV depth deviation and suppressed Cu contamination to less than 1e11 atoms/cm2. However, after direct Si/Cu grinding with an 8000 grit grinding wheel, the average surface roughness of Si was 5–10 nm, which is larger than that after chemical mechanical polishing (CMP). In this paper, we developed vitrified grinding wheels with very high grit numbers (#30,000 and #45,000) and present an improved version of our TSV reveal process. The average surface roughness of Si after Si/Cu grinding was approximately 3 nm for the 30,000 grit grinding wheel and 1 nm for the 45,000 grit grinding wheel. This value is equivalent to that after CMP. The improved process produced a uniform reveal of 4-um-diameter TSVs without TSV depth deviation and Cu contamination. The Cu contaminant concentration on Si region between TSVs was small (<3e10 atoms/cm2). This process will reduce the cost of the TSV reveal process and considerably improve the TSV yield.

scholarly journals Effect of finishing and polishing methods on surface roughness of autopolymerized acrylic resins

2017 ◽  
Vol 65 (4) ◽  
pp. 303-307
Author(s):  
Gabriel Lúcio Calazans DUARTE ◽  
Angélica Kercya Pereira de MENDONÇA ◽  
Ana Roberta Assunção de FREITAS ◽  
Antônio Ricardo Calazans DUARTE ◽  
Julita de Campos Pipolo HOLANDA
Keyword(s):  
Surface Roughness ◽  
Acrylic Resin ◽  
T Test ◽  
Test Results ◽  
Acrylic Resins ◽  
Significant Difference ◽  
Student’S T ◽  
Student’S T Test

ABSTRACT Objective : To evaluate the surface roughness of two makes of autopolymerized acrylic resin (Classic Dencor® and Duralay®) with two different methods of finishing and polishing (conventional and using the Dhpro® finishing & polishing kit). Methods : A total of 20 specimens (10 of each make) was obtained using Zetalabor®--Zhermak condensation silicone molds. After polymerization, 20 blocks of resin were divided in two and subjected to two types of finishing and polishing, one at each end. The types of finishing and polishing were as follows: conventional (lathe) and using the Dhpro® finishing & polishing kit. Once finished and polished, the specimens were subjected to surface roughness testing using a roughness meter and were analyzed via the Student’s t-test. Results : There is a statistically significant difference between the forms of polishing, unrelated to the brand of acrylic resin. Conventional polishing achieved a level of 0.12 µm for both resins and the DhPro® polishing presented roughness a little above 0.2 µm. Conclusion : Conventional polishing is superior to the DhPro® kit, as it achieves lower levels of roughness. There is no significant difference between the acrylic resins in terms of surface roughness after the finishing and polishing processes.

scholarly journals Ultrasonic dispersion method used in glass polishing experiment

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110118
Author(s):  
Zenan Chu ◽  
Tao Wang ◽  
Qiang He ◽  
Kai Zhao
Keyword(s):  
Surface Roughness ◽  
Rare Earth ◽  
Surface Morphology ◽  
Ultrasonic Method ◽  
Average Surface Roughness ◽  
Polishing Process ◽  
Ultrasonic Dispersion ◽  
Processing Efficiency ◽  
Average Surface ◽  
Evaluation Indexes

To solve the problems of low processing efficiency and poor glass surface quality when using rare earth polishing powder to grind super-hard K9 glass. The potential, phase structure, surface morphology, and particle size distribution of the nano-rare earth polishing powder were characterized. Compare the evaluation indexes such as polishing efficiency, surface morphology, and contact angle after the polishing process is changed. The results of the comparative study show that the average surface roughness of the glass after heating ultrasonic polishing process is 0.9064 nm, the polishing rate reaches 0.748 μm/min, the average surface roughness of the glass without heating ultrasonic polishing process is 1.3175 nm, and the polishing rate reaches 0.586 μm/min, the ultrasonic assisted polishing process is superior to the conventional polishing process. The heating ultrasonic method provides experimental basis for precise and rapid processing.

EFFECT OF ABRASIVE TYPE ON THE SURFACE ROUGHNESS AND MRR IN MAF OF AISI 304 STEEL

2021 ◽  
Author(s):  
MAHMUT ÇELIK ◽  
HAKAN GÜRÜN ◽  
ULAŞ ÇAYDAŞ
Keyword(s):  
Surface Roughness ◽  
Removal Rate ◽  
Three Dimensional ◽  
Steel Plates ◽  
304 Stainless Steel ◽  
Average Surface Roughness ◽  
Machining Time ◽  
Aisi 304 ◽  
Average Surface ◽  
Different Levels

In this study, the effects of experimental parameters on average surface roughness and material removal rate (MRR) were experimentally investigated by machining of AISI 304 stainless steel plates by magnetic abrasive finishing (MAF) method. In the study in which three different abrasive types were used (Al2O3, B4C, SiC), the abrasive grain size was changed in two different levels (50 and 80[Formula: see text][Formula: see text]m), while the machining time was changed in three different levels (30, 45, 60[Formula: see text]min). Surface roughness values of finished surfaces were measured by using three-dimensional (3D) optical surface profilometer and surface topographies were created. MRRs were measured with the help of precision scales. The abrasive particles’ condition before and after the MAF process was examined and compared using a scanning electron microscope. As a result of the study, the surface roughness values of plates were reduced from 0.106[Formula: see text][Formula: see text]m to 0.028[Formula: see text][Formula: see text]m. It was determined that the best parameters in terms of average surface roughness were 60[Formula: see text]min machining time with 50[Formula: see text][Formula: see text]m B4C abrasives, while the best result in terms of MRR was taken in 30[Formula: see text]min with 50[Formula: see text][Formula: see text]m SiC abrasives.

In-Process Prediction of Surface Roughness in Grinding Process by Monitoring of Cutting Force Ratio

2014 ◽  
Vol 627 ◽  
pp. 29-34 ◽  
Author(s):  
Vichaya Thammasing ◽  
Somkiat Tangjitsitcharoen
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Spindle Speed ◽  
Least Square ◽  
Depth Of Cut ◽  
Grinding Process ◽  
Average Surface Roughness ◽  
Average Surface ◽  
Developed Surface ◽  
Force Ratio

The purpose of this research is to develop the models to predict the average surface roughness and the surface roughness during the in-process grinding by monitoring the cutting force ratio. The proposed models are developed based on the experimentally obtained results by employing the exponential function with four factors, which are the spindle speed, the feed rate, the depth of cut, and the cutting force ratio. The experimentally obtained results showed that the dimensionless cutting force ratio is usable to predict the surface roughness during the grinding process, which can be calculated and obtained by taking the ratio of the corresponding time records of the cutting force Fy in the spindle speed direction to that of the cutting force Fz in the radial wheel direction. The multiple regression analysis is utilized to calculate the regression coefficients with the use of the least square method at 95% confident level. The experimentally obtained models have been verified by the new cutting tests. It is proved that the developed surface roughness models can be used to predict the in-process surface roughness with the high accuracy of 93.9% for the average surface roughness and 92.8% for the surface roughness.

scholarly journals Evaluating the Effect of Slow-Stroke Back Massage on the Anxiety of Candidates for Cataract Surgery

2019 ◽  
Vol 12 (2) ◽  
pp. 12-17
Author(s):  
Maryam Keramati, MD ◽  
Mohammad Sadegh Sargolzaei, MSc ◽  
Ali Moghadasi ◽  
Mohammad Hasan Basirinezhad, MSc ◽  
Reza Mohammadpourhodki
Keyword(s):  
Cataract Surgery ◽  
Intervention Group ◽  
T Test ◽  
Control Group ◽  
Paired Samples ◽  
Significant Difference ◽  
Student’S T ◽  
Dependent Samples ◽  
Student’S T Test ◽  
Back Massage

Background: The patients under cataract sur-gery often experience anxiety not only during the surgery, but also prior to the surgery.Purpose: We sought to determine the effects of slow-stroke back massage on anxiety in patients undergoing cataract surgery. Setting: The study was conducted in the Amiral-momenin Hospital of Zabol city, south-east of Iran.Participants: A total of 60 candidates of cataract surgery participated in the study.Research Design: The participants were ran-domly allocated to either control or intervention groups. The intervention group received slow-stroke back massages, while patients in control group received routine interventions.Intervention: The slow-stroke back massage was performed on the patients assigned to the interven-tion group. The intervention was performed in the morning of the surgery day at 30 minutes before the surgery. The researcher performed each mas-sage session in a sitting position. The duration of each massage session was 15 minutes. Main Outcome Measures: Anxiety was assessed in the both groups in the morning of the surgery, before and immediately after the intervention. In-dependent samples Student’s t test, paired samples Student’s t test, and chi-squared test were used to analyze the data.Results: Anxiety was not significantly different between the two groups before and after the mas-sage (p = .816). On the other hand, paired samples Student’s t test showed a significant difference comparing the anxiety scores before (49.7±5.43) and after (45.16±3.89) the massage in the interven-tion group (p < .001). Conclusions: Based on our results, slow-stroke back massage, which is a low-cost and safe method, reduced anxiety in patients who were candidates for cataract surgery.

scholarly journals Influence of toothbrushing on enamel softening and abrasive wear of eroded bovine enamel: an in situ study

2006 ◽  
Vol 20 (2) ◽  
pp. 148-154 ◽  
Author(s):  
Daniela Rios ◽  
Heitor Marques Honório ◽  
Ana Carolina Magalhães ◽  
Marília Afonso Rabelo Buzalaf ◽  
Regina Guenka Palma-Dibb ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
The Other ◽  
In Situ Study ◽  
Significant Difference ◽  
The Mean ◽  
Student’S T ◽  
Bovine Enamel ◽  
Enamel Layer ◽  
Student’S T Test

This study assessed the surface softening and abrasive wear of eroded bovine enamel with or without the influence of toothbrushing. Five volunteers took part in this in situ study of 5 days. They wore acrylic palatal appliances containing 6 bovine enamel blocks divided in two rows with 3 blocks, which corresponded to the studied groups: erosion without toothbrushing (GI) and erosion with toothbrushing (GII). The blocks were subjected to erosion by immersion of the appliances in a cola drink for 10 minutes, 4 times a day. After that, no treatment was performed in one row (GI), whereas the other row was brushed (GII). The appliance was then replaced into the mouth. Enamel alterations were determined using profilometry and microhardness tests. Data were tested using paired Student’s t test (p < 0.05). The mean wear values (µm) and percentage of superficial microhardness change (%SMHC) were respectively: GI - 2.77 ± 1.21/91.61 ± 3.68 and GII - 3.80 ± 0.91/58.77 ± 11.47. There was a significant difference in wear (p = 0.001) and %SMHC (p = 0.001) between the groups. It was concluded that the wear was more pronounced when associated to toothbrushing abrasion. However, toothbrushing promoted less %SMHC due to the removal of the altered superficial enamel layer.

Endothelium increases medial hydraulic conductance of aorta, possibly by release of EDRF

1993 ◽  
Vol 264 (1) ◽  
pp. H26-H32 ◽  
Author(s):  
A. L. Baldwin ◽  
L. M. Wilson
Keyword(s):  
Methyl Ester ◽  
Endothelial Permeability ◽  
Rabbit Aorta ◽  
Hydraulic Conductance ◽  
Control Value ◽  
New Zealand White Rabbits ◽  
Student’S T ◽  
Low Pressures ◽  
Student’S T Test

In eight anesthetized New Zealand White rabbits, the aorta was cannulated in situ for measurement of hydraulic conductance (Lp) at different pressures with and without endothelium. De-endothelialization increased Lp at > or = 75 mmHg but not at 50 mmHg. Because endothelium resists transmural water flow, the endothelium must also increase medial Lp at 50 mmHg. To determine whether this effect results from secretion of endothelial-derived relaxing factor (EDRF), Lp was measured in eight rabbits in the presence and absence of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of EDRF synthesis. At 50 mmHg L-NAME reduced Lp from 6.79 +/- 2.19 to 2.59 +/- 1.41 (SD) x 10(-8) (P < 0.05, paired Student's t test). After L-NAME was removed, Lp returned to its control value. At 125 mmHg L-NAME did not significantly change Lp, although endothelial permeability seemed to increase. L-NAME did not affect Lp of nine de-endothelialized vessels at either pressure. An additional five experiments showed that the effect of L-NAME at 50 mmHg was reversed by L-arginine. Eleven additional experiments demonstrated that NG-nitro-D-arginine methyl ester does not affect Lp at 50 mmHg. These results indicate that EDRF increases Lp of the rabbit aorta at low pressures.

scholarly journals Biomechanical evaluation between orthodontic attachment and three different materials after various surface treatments: A three-dimensional optical profilometry analysis

2019 ◽  
Vol 89 (5) ◽  
pp. 742-750
Author(s):  
İrem Kurt ◽  
Zafer Cavit Çehreli ◽  
Ayça Arman Özçırpıcı ◽  
Çağla Şar
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Material Surface ◽  
Original Material ◽  
Average Surface Roughness ◽  
Average Surface ◽  
Diamond Bur ◽  
Monolithic Zirconia ◽  
Feldspathic Porcelain ◽  
The Impact

ABSTRACT Objectives: To determine the best bonding method of orthodontic attachment among monolithic zirconia, feldspathic porcelain, hybrid porcelain, and the impact of surface-conditioning methods using a three-dimensional optical profilometer after debonding. Materials and Methods: 56 feldspathic porcelain, 56 monolithic zirconia, and 56 hybrid porcelain samples were divided into four surface treatment subgroups: (1) hydrofluoric (HF) acid etch + silane, (2) Al2O3 sandblasting + silane, (3) silicoating (SiO2), and (4) diamond bur + silane. The specimens were tested to evaluate shear bond strength (SBS). Residual composite was removed after debonding. Three-dimensional white-light interferometry was used to obtain quantitative measurements on surface roughness. Results: The highest SBS value was found for the HF acid–etched feldspathic porcelain group. The average surface roughness values were significantly higher in all material groups in which diamond bur was applied, while roughening with Cojet provided average surface roughness values closer to the original material surface. Conclusions: Variations in structures of the materials and roughening techniques affected the SBS and surface roughness findings.

scholarly journals The examination of the effect of variable cutting speeds on the surface and edge qualities of milled granite materials

2019 ◽  
Vol 11 (7) ◽  
pp. 168781401983631 ◽  
Author(s):  
István Gábor Gyurika ◽  
Tibor Szalay
Keyword(s):  
Surface Roughness ◽  
Cutting Speed ◽  
Sample Surface ◽  
Average Surface Roughness ◽  
Edge Chipping ◽  
Average Surface ◽  
Grain Sizes ◽  
Natural Stones ◽  
Cutting Speeds

Automated stone manufacturing has undergone considerable development in recent years. Thanks to international research dealing with the cutting, sawing and grinding of different natural stones, processing time shortens and tool-life lengthens. However, the process of stone milling has not been extensively examined yet, primarily because of the novelty of this technology. The aim of the research described in this article is to examine how variable cutting speed affects the quality of workpiece edges while milling granite materials. For the research, sample surfaces were formed on five granite slabs with different average grain sizes using five cutting speed values. Afterwards, changes in the average surface roughness and average edge chipping rate were examined. From the research results, it can be concluded that, due to an increase in cutting speed, the average edge chipping rate will decrease until reaching a borderline speed. In the case of a higher cutting speed, the referent tendency cannot be ascertained. A statistical analysis conducted in the scope of this research showed that if a variable cutting speed is applied, then changes in the quality of the sample surface edge can be inferred from the development trends of average surface roughness.

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