A Study of Surface Characteristics of Flank Lock Type Precision Locknut Under a Vertical Installation

2016 ◽  
Vol 34 (1) ◽  
pp. 47-58 ◽  
Author(s):  
C.-M. Chen ◽  
C.-H. Sun
Keyword(s):  
Surface Roughness ◽  
Contact Surface ◽  
Surface Characteristics ◽  
Thread Surface ◽  
Surface Flatness ◽  
Before And After ◽  
Set Up

AbstractThe study attempted to observe the surface characteristics of the flank lock type precision locknut which was assembled in a vertical type and operates under different tightening speed. The speed setting was in according with the specifications of 4rpm, 6rpm and 8rpm conditions to set up this experiment. A type of 2TML lubricant was used. The experiment investigated the surface characteristics of a locknut, including contact surface flatness, contact surface roughness, and thread surface roughness before and after the designed test. According to the contact surface flatness of the locknut obtained from this study, it was found that the surface of the locknut contacting with the bearing resulted into a deterioration of the surface flatness and surface roughness during the tests. Furthermore, the thread surface roughness has been changed at different thread for different tightening speed during the test, especially at threads 1, 2, 7 and 8. The study found that some of variations occurred in the values of Ra, Rz and Rmax at different thread of a locknut. The variation of Rmax is the most among them.

A Method to Measure Contact Pressure Between Metallic Surfaces by Changes in Surface Roughness

1981 ◽  
Vol 103 (2) ◽  
pp. 210-217 ◽  
Author(s):  
S. Kato ◽  
K. Yamaguchi ◽  
T. Kato
Keyword(s):  
Surface Roughness ◽  
Pressure Distribution ◽  
Elasticity Theory ◽  
Contact Surface ◽  
Flat Surface ◽  
Metallic Surfaces ◽  
Interface Pressure ◽  
Roughness Change ◽  
Before And After ◽  
Contact Surfaces

A new method was developed to find the interface pressure distribution of metallic surfaces in contact by measuring the roughness change. The pressure distribution of two kinds of contact surfaces, a sphere and a flat surface, a flat end of a cylinder and a flat surface, was measured experimentally by the method and compared with that of the elasticity theory. As a result, it was shown that it is possible to find the pressure distribution by measuring the roughness change in the contact surface before and after contact.

Surface Roughness and Droplet Contact Angle Measurement of Various Orthodontic Bonding Cements

1993 ◽  
Vol 20 (4) ◽  
pp. 297-305 ◽  
Author(s):  
C. O'Kane ◽  
R. G. Oliver ◽  
R. E. Blunden
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Glass Ionomer Cement ◽  
Surface Characteristics ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Bacterial Attachment ◽  
Before And After ◽  
Orthodontic Bonding

Surface characteristics that are considered important for bacterial attachment to thirteen orthodontic bonding composite cements and one glass ionomer cement were examined in vitro before and after toothbrush abrasion. The surface roughness and contact angle measurements were found to be statistically significantly different between the materials, both before and after brushing, and there were also statistically significant changes within materials after brushing. There were low correlation coefficients between surface roughness and contact angle for both pre-and post-brushed materials.

scholarly journals The Effect of Thermocycling and Surface Treatments on the Surface Roughness and Microhardness of Three Heat-Pressed Ceramics Systems

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 160 ◽  
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin-Daniel Porojan ◽  
Mihaela-Ionela Bîrdeanu ◽  
Ion-Dragoș Uțu ◽  
Liliana Porojan
Keyword(s):  
Surface Roughness ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
In Vitro Study ◽  
Surface Characteristics ◽  
Surface Treatments ◽  
Lithium Silicate ◽  
Before And After ◽  
Microhardness Tester

Dental ceramic restorations are widely used in restorative dentistry. However, these restorations can be affected once cemented in the oral cavity by several factors. How can conventional surface treatments, such as glazing and mechanical polishing, diminish the effects of aging? The purpose of this in vitro study was to evaluate the effect of thermocycling and conventional surface treatments on the surface roughness and microhardness of three types of glass-ceramics by using a profilometer, scanning electron microscopy (SEM), atomic force microscopy (AFM), and a microhardness tester. Three types of ceramic systems (zirconia reinforced lithium silicate glass-ceramic, lithium disilicate glass-ceramic, and feldspathic glass-ceramic) (n = 48) were prepared. The samples were subjected to thermocycling for 10,000 cycles. Surface roughness was evaluated numerically using a profilometer and visually by using SEM and AFM. Microhardness was performed using a microhardness tester. The data were interpreted using the ANOVA test, and the results were correlated using Pearson’s correlation formula (r). Significant differences were found before and after thermocycling for the Ra (p < 0.01) and Rz (p < 0.05) parameters. As well, differences between glazed and polished surfaces were significant before and after thermocycling for surface roughness and microhardness (p < 0.05). A correlation was made between average surface roughness and microhardness (r = −460) and for the maximum surface roughness and microhardness (r = −606). Aging increases the roughness and decreases in time the microhardness. The tested ceramic systems behaved differently to the aging and surface treatments. Surface treatments had a significant impact on the microhardness and surface characteristics. The glazed groups were reported with higher surface roughness and lower microhardness when compared to the polished groups before and after thermocycling. The measuring roughness techniques determine the scale-dependent values for the Ra (Sa) and Rz (Sq) parameters. Thermocycling almost doubled the surface roughness for all the tested samples. Microhardness decreased only for the Celtra glazed samples. Nano-roughness increased the values for Vita and slightly for Emax. Thermocycling had little effect on Emax ceramic and a more significant impact on Celtra Press ceramic.

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.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

scholarly journals Biofilm inhibition and bactericidal activity of NiTi alloy coated with graphene oxide/silver nanoparticles via electrophoretic deposition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sirapat Pipattanachat ◽  
Jiaqian Qin ◽  
Dinesh Rokaya ◽  
Panida Thanyasrisung ◽  
Viritpon Srimaneepong
Keyword(s):  
Surface Roughness ◽  
Silver Nanoparticles ◽  
Graphene Oxide ◽  
Electrophoretic Deposition ◽  
Biofilm Formation ◽  
Niti Alloy ◽  
Surface Characteristics ◽  
Dependent Manner ◽  
Biofilm Inhibition ◽  
Coating Time

AbstractBiofilm formation on medical devices can induce complications. Graphene oxide/silver nanoparticles (GO/AgNPs) coated nickel-titanium (NiTi) alloy has been successfully produced. Therefore, the aim of this study was to determine the anti-bacterial and anti-biofilm effects of a GO/AgNPs coated NiTi alloy prepared by Electrophoretic deposition (EPD). GO/AgNPs were coated on NiTi alloy using various coating times. The surface characteristics of the coated NiTi alloy substrates were investigated and its anti-biofilm and anti-bacterial effect on Streptococcus mutans biofilm were determined by measuring the biofilm mass and the number of viable cells using a crystal violet assay and colony counting assay, respectively. The results showed that although the surface roughness increased in a coating time-dependent manner, there was no positive correlation between the surface roughness and the total biofilm mass. However, increased GO/AgNPs deposition produced by the increased coating time significantly reduced the number of viable bacteria in the biofilm (p < 0.05). Therefore, the GO/AgNPs on NiTi alloy have an antibacterial effect on the S. mutans biofilm. However, the increased surface roughness does not influence total biofilm mass formation (p = 0.993). Modifying the NiTi alloy surface using GO/AgNPs can be a promising coating to reduce the consequences of biofilm formation.

scholarly journals Using uniform design and regression methodology of turning parameters study of nickel alloy

2021 ◽  
Author(s):  
Shao-Hsien Chen ◽  
Chih-Hung Hsu
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Nickel Alloy ◽  
Design Methodology ◽  
Cutting Tool ◽  
Uniform Design ◽  
Machining Time ◽  
Variable Parameters ◽  
Cutting Test ◽  
Set Up

AbstractThe nickel alloy has good mechanical strength and corrosion resistance at high temperature; it is extensively used in aerospace and biomedical and energy industries, as well as alloy designs of different chemical compositions to achieve different mechanical properties. However, for high mechanical strength, low thermal conductivity, and surface hardening property, the nickel alloy has worse cutting tool life and machining efficiency than general materials. Therefore, how to select the optimum machining parameters will influence the workpiece quality, cost, and machining time. This research will be using a new experimental design methodology to the cutting parameter planning for nickel-based alloy cutting test, and used the uniform design methodology to cutting test to reduce the number of experiments. Three independent variable parameters are set up, including cutting speed, feed rate, and cutting depth, and four dependent variable parameters are set up, including cutting tool wear, surface roughness, machining time, and cutting force. A nickel alloy turning parameter model is built by using regression analysis to further predict the I/O relationship among various combinations of variables. The errors between actual values and prediction values are validated. When the cutting tool wear (VB) is 2.72~6.18%, the surface roughness (Ra) is 4.10~7.72%, the machining time (T) is 3.75~8.82%, and the cutting force (N) is 1.54~7.42%; the errors of various dependent variables are approximately less than 10%, so a high precision estimation model is obtained through a few experiments of uniform design method.

scholarly journals The Effects of Toothbrush Wear on the Surface Roughness and Gloss of Resin Composites with Various Types of Matrices

2021 ◽  
Vol 9 (1) ◽  
pp. 8
Author(s):  
Murtadha AlAli ◽  
Nikolaos Silikas ◽  
Julian Satterthwaite
Keyword(s):  
Surface Roughness ◽  
Pairwise Comparisons ◽  
Resin Composites ◽  
Hybrid Resin ◽  
Before And After ◽  
Post Hoc ◽  
Main Effects ◽  
Toothbrush Wear

Objective: To evaluate and compare the surface roughness and gloss of a DMA-free composite and Bis-GMA-free composite with a DMA-based composite before and after toothbrushing simulation. Materials and Methods: Fifteen dimensionally standardised composite specimens of three nano-hybrid resin composites (Tetric EvoCeram, Admira Fusion, and Venus Diamond) were used. Five specimens from each composite were polished and then subjected to a toothbrushing simulator. Surface roughness (Ra) and gloss were measured before toothbrushing and after 5000, 10,000, 15,000, and 20,000 toothbrushing cycles. The data was analysed using 5 × 3 ANOVA to assess surface roughness and gloss values and pairwise comparisons in the form of Tukey post hoc tests were performed to interpret main effects. Results: For all tested materials, surface roughness increased, and gloss decreased after toothbrushing abrasion. Surface roughness (Ra) values ranged from 0.14 to 0.22 μm at baseline and increased to between 0.41 and 0.49 μm after 20,000 toothbrushing cycles. Gloss values ranged between 31.9 and 50.6 GU at baseline and between 5.1 and 19.5 GU after 20,000 toothbrushing cycles. The lowest initial Ra value was detected in Venus Diamond and the highest initial gloss value was detected in Tetric EvoCeram. Conclusions: Simulated toothbrushing abrasion led to an increase in surface roughness and a decrease in gloss for all tested materials. Venus Diamond had the smoothest surface and Tetric EvoCeram had the glossiest surface after polishing and following 20,000 cycles of toothbrushing abrasion. Admira Fusion demonstrated the roughest surface and had the lowest gloss values before and after toothbrushing abrasion.

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.

Modeling of surface roughness in a novel magnetorheological gear profile finishing process

2020 ◽  
pp. 095440622097826
Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora
Keyword(s):  
Surface Roughness ◽  
Gear Tooth ◽  
Surface Characteristics ◽  
Spur Gear ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Finishing Process ◽  
Gear Profile

Fine finishing of spur gears reduces the vibrations and noise and upsurges the service life of two mating gears. A new magnetorheological gear profile finishing (MRGPF) process is utilized for the fine finishing of spur gear teeth profile surfaces. In the present study, the development of a theoretical mathematical model for the prediction of change in surface roughness during the MRGPF process is done. The present MRGPF is a controllable process with the magnitude of the magnetic field, therefore, the effect of magnetic flux density (MFD) on the gear tooth profile has been analyzed using an analytical approach. Theoretically calculated MFD is validated experimentally and with the finite element analysis. To understand the finishing process mechanism, the different forces acting on the gear surface has been investigated. For the validation of the present roughness model, three sets of finishing cycle experimentations have been performed on the spur gear profile by the MRGPF process. The surface roughness of the spur gear tooth surface after experimentation was measured using Mitutoyo SJ-400 surftest and is equated with the values of theoretically calculated surface roughness. The results show the close agreement which ranges from −7.69% to 2.85% for the same number of finishing cycles. To study the surface characteristics of the finished spur gear tooth profile surface, scanning electron microscopy is used. The present developed theoretical model for surface roughness during the MRGPF process predicts the finishing performance with cycle time, improvement in the surface quality, and functional application of the gears.

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