scholarly journals Effects of debonding a conventional & customized lingual appliance on enamel structure- An invitro study

2020 ◽  
Vol 10 (3) ◽  
pp. 14-20
Author(s):  
Robin Malik ◽  
Anmol S Kalha Osre ◽  
Anil K. Chandna ◽  
Amrita Puri ◽  
Riddhi Chawla
Keyword(s):  
Surface Roughness ◽  
Optical Microscope ◽  
Irreversible Damage ◽  
Bonding Material ◽  
Enamel Structure ◽  
Roughness Index ◽  
Lingual Appliance ◽  
Conventional Brackets ◽  
Arch Forms ◽  
Surface Changes

Introduction: To evaluate the surface changes on enamel structure after debonding of customized and conventional lingual brackets bonded using restorative dual cure bonding material and a chemically cured bonding material with and without sandblasting. Materials and Method: The sample consisted of 40 premolar teeth extracted for the purpose of orthodontic treatment. Enamel surface changes, prior to bonding, were studied using a stereomicroscope (Olympus SZX7) and an optical microscope. 20 extracted premolars were arranged in 2 arch forms with 5 teeth in each quadrant, after which impression of the arches with rubber base impression material was made. These impressions were then sent to the laboratory for the fabrication of a customized lingual appliance. The remaining 20 premolars were divided into 2 arches, each arch having 10 extracted premolars divided into 4 sets, 1st to test customized brackets bonded with chemical cure resin without sandblasting, 2nd to test customized brackets with dual cure resin without sandblasting, 3rd to test conventional brackets with chemical sure resin with and without sandblasting and 4th to test conventional brackets bonded with dual cure resin with and without sandblasting. The post debonding photographs were analyzed using a standardized grid and Surface Roughness Index. Result: Thus, enamel defects are likely to be caused post debonding despite of using any combination. However, the surface roughness index has been shown to be highest post debonding in cases where customized brackets have been bonded using dual cure resin along with sandblasting. Conclusion: While a clinician may opt for a material like Rely X U200 to bond lingual appliances in order to have a better clinical management of the appliance, but he would have to keep the possibility of irreversible damage to enamel post debonding.

scholarly journals EFFECT OF SOIL TILLAGE AND PLANT RESIDUE ON SURFACE ROUGHNESS OF AN OXISOL UNDER SIMULATED RAIN

2015 ◽  
Vol 39 (1) ◽  
pp. 268-278 ◽  
Author(s):  
Elói Panachuki ◽  
Ildegardis Bertol ◽  
Teodorico Alves Sobrinho ◽  
Paulo Tarso Sanches de Oliveira ◽  
Dulce Buchala Bicca Rodrigues
Keyword(s):  
Surface Roughness ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Plant Residue ◽  
Soil Tillage ◽  
No Tillage ◽  
Maize Crop ◽  
Minimum Tillage ◽  
Roughness Index ◽  
Simulated Rain

Surface roughness of the soil is formed by mechanical tillage and is also influenced by the kind and amount of plant residue, among other factors. Its persistence over time mainly depends on the fundamental characteristics of rain and soil type. However, few studies have been developed to evaluate these factors in Latossolos (Oxisols). In this study, we evaluated the effect of soil tillage and of amounts of plant residue on surface roughness of an Oxisol under simulated rain. Treatments consisted of the combination of the tillage systems of no-tillage (NT), conventional tillage (CT), and minimum tillage (MT) with rates of plant residue of 0, 1, and 2 Mg ha-1 of oats (Avena strigosa Schreb) and 0, 3, and 6 Mg ha-1 of maize (Zea mays L.). Seven simulated rains were applied on each experimental plot, with intensity of 60±2 mm h-1 and duration of 1 h at weekly intervals. The values of the random roughness index ranged from 2.94 to 17.71 mm in oats, and from 5.91 to 20.37 mm in maize, showing that CT and MT are effective in increasing soil surface roughness. It was seen that soil tillage operations carried out with the chisel plow and the leveling disk harrow are more effective in increasing soil roughness than those carried out with the heavy disk harrow and leveling disk harrow. The roughness index of the soil surface decreases exponentially with the increase in the rainfall volume applied under conditions of no tillage without soil cover, conventional tillage, and minimum tillage. The oat and maize crop residue present on the soil surface is effective in maintaining the roughness of the soil surface under no-tillage.

Effect of Tightening Speed on the Torque-Tension and Wear Pattern in Bolted Connections

2006 ◽  
Author(s):  
Sayed A. Nassar ◽  
Ramanathan M. Ranganathan ◽  
Saravanan Ganeshmurthy ◽  
Gary C. Barber
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Surface Roughness ◽  
Initial Level ◽  
Zinc Coating ◽  
Optical Microscope ◽  
Wear Pattern ◽  
Highly Sensitive ◽  
Contact Surfaces ◽  
Scanning Electron

This experimental study investigates the effect of tightening speed and coating on both the torque – tension relationship and wear pattern in threaded fastener applications. The fastener torque – tension relationship is highly sensitive to normal variations in the coefficients of friction between threads and between the turning head and the surface of the joint. Hence, the initial level of the joint clamp load and the overall integrity and reliability of a bolted assembly is significantly influenced by the friction coefficients. The effect of repeated tightening and loosening is also investigated using M12, Class 8.8, fasteners with and without zinc coating. The torque – tension relationship is examined in terms of the non-dimensional nut factor K. The wear pattern is examined by monitoring the changes in surface roughness using a WYKO optical profiler and by using a LECO optical microscope. A Hitachi S-3200N Scanning Electron Microscope (SEM) is used to examine the contact surfaces, under the fastener head, after each tightening/loosening cycle. Experimental data on the effect of variables and the tightening speed, fastener coating and repeated tightening on the nut factor are presented and analyzed for M8 and M12, class 8.8, fasteners.

scholarly journals PELAPISAN PERMUKAAN DALAM NOSEL ROKET RKX100 DENGAN Cr2C3-NiCr HVOF: OPTIMASI KEKUATAN LEKAT MELALUI VARIASI KEKASARAN PERMUKAAN

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Bondan T.Sofyan ◽  
Yus Prasetyo ◽  
Sayid Ardiansyah ◽  
Yus Prasetyo ◽  
Edy Sofyan
Keyword(s):  
Surface Roughness ◽  
Thermal Spray ◽  
Bonding Strength ◽  
Spray Coating ◽  
Hardness Measurement ◽  
Thermal Spray Coating ◽  
Optical Microscope ◽  
Mechanical Interlocking ◽  
Micro Hardness ◽  
Scanning Electron

Nozzle of RKX100 rocket contributes 30 percent to the total weight of the structure, so that allowing further research on weight reduction. An alternative for this is by substitution of massive graphite, which is currently used as thermal protector in the nozzle, with thin layer of HVOF (High Velocity Oxy-Fuel) thermal spray layer. A series of study on the characteristics of various type of HVOF coating material have been being conducted. This paper presented the investigation on the HVOF Cr2C3-NiCr thermal spray coating, in particular, the optimization of bonding strength by varying surface roughness of substrates. Characterization included bonding strength test, micro hardness measurement and micro structural observation with optical microscope and scanning electron micriscope (SEM). The results showed that grit blasting pressure increass the surface roughness from 4,54 um to 5.72 um at the pressure of 6 bar. Average micro hardness of the coating was 631 VHN 300. Coating applied to the surface with rougness of 5.42 um possessed the highest bonding strength, 44 MPa. Microstructural observation by using optical microscope and scanning electron microscope (SEM) confirmed dense lamellae structure with variable composition. High coating adherence was found to be due to mechanical interlocking.

THE EFFECT OF ALUMINUM ELECTROPOLISHING ON NANO-PORES ARRANGEMENT IN ANODIC ALUMINA MEMBRANES

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3267-3277 ◽  
Author(s):  
M. H. RAHIMI ◽  
S. H. TABAIAN ◽  
S. P. HOVEYDA MARASHI ◽  
M. AMIRI ◽  
M. M. DALALY ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Pure Aluminum ◽  
Optical Microscope ◽  
Anodic Alumina ◽  
The Other ◽  
Sem Images ◽  
Current Time ◽  
Nanoporous Anodic Alumina ◽  
Alumina Membranes ◽  
Stress Relieving

Surface conditions of aluminum can influence the final arrangement of nano-pores in fabrication of ordered nanoporous anodic alumina membranes (AAMs). This study is mainly focused on the different applied voltages of aluminum electropolishing by keeping all the other parameters constant. After heat treatment (stress relieving and annealing at 500°C) of pure aluminum sheets, the samples were electropolished at different voltages (10-60V) to obtain desirable surface smoothness, while the temperature of the container was kept constant. The current-time curves were recorded during electropolishing process. The surface roughness obtained in each applied voltage was examined using optical microscope and atomic force microscope (AFM). The process was followed by two-step anodization in order to reach ordered nano-pores. Finally, the influence of surface roughness on regularity of nano-pores was observed using scanning electron microscope (SEM). The SEM images were analyzed to investigate the morphology and the degree of self ordering of pores of the samples by using a new designed analytical method aiming MATLAB and fast Fourier transform (FFT) technique. It was concluded that the electropolishing voltage and the resulted surface roughness and also formed defects can competitively affect the arrangement of membrane's nano-pores. A desired smoothness obtained from electropolishing voltage of 30V. Also 40V provided the best order with respect to the other voltages.

Effect of thermomechanical densification of pine wood (Pinus sylvestris L.) on cutting forces and roughness during milling

2021 ◽  
Vol 113 ◽  
pp. 36-42
Author(s):  
Barbara Białowąs ◽  
Karol Szymanowski
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Statistical Analysis ◽  
Pinus Sylvestris ◽  
Cutting Forces ◽  
Physical And Mechanical Properties ◽  
Milling Process ◽  
Pine Wood ◽  
Roughness Index ◽  
Modified Wood

Effect of thermomechanical densification of pine wood (Pinus sylvestris L.) on cutting forces and roughness during milling. The paper presents the results of research concerning the assessment of machinability of pine wood thermomechanically compacted. The assessment was made on the basis of the cutting forces and surface roughness after the milling process. Selected properties of native and modified wood were examined. Based on the research, it was found that compacted wood is characterized by higher cutting forces during milling. The surface quality after milling was examined and the roughness index Ra values were determined. The research shows that the modified wood is characterized by a lower Ra value both along and across the grain. Statistical analysis showed that the modification had a statistically significant effect on the values of cutting forces and the physical and mechanical properties of the tested wood.

Grain Structure and Surface Roughness of Four Commercial NiTi Orthodontic Archwires

2017 ◽  
Vol 266 ◽  
pp. 257-263
Author(s):  
Wassana Wichai ◽  
Rutchadakorn Isarapatanapong ◽  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Optical Microscope ◽  
Grain Structure ◽  
Wire Surface ◽  
Average Grain Size ◽  
Electron Mode ◽  
The Mean ◽  
The Wire ◽  
Orthodontic Archwires

This study investigated four commercially available NiTi orthodontic archwires from different manufactures for their grain structure and surface roughness.Four commercially available pre-formed NiTi orthodontic archwire (Ormco, Sentalloy, Highland and NIC) with diameter 0.016 x 0.022 inch2 were tested. The wire samples were polished and etched to evaluate the morphology and structure of wire surface. Each NiTi archwire was investigated under a reflected light microscope of an Optical Microscope to analyze its grain structure and size, in longitudinal surfaces. The surfaces of wire were qualitatively examined in the secondary electron mode at common magnification (500X). The surface roughness was also evaluated by a surface roughness tester. The descriptive statistic was evaluated the mean and standard deviation of surface roughness and Medcale T-Test was to test the mean difference of the surface roughness in each brands. This study showed an average grain size of 2-8 μm for each NiTi archwire. The wire surface of Ormco and Highland showed straiations along the longitudinal axes, however Sentalloy and NIC showed small pores on the wire surface. The surface roughness was 0.09 μm for Highland, 0.25 μm for Sentalloy, 0.28 μm for Ormco and 0.46 μm for NIC archwire. The Highland was smoothest and NIC was the roughest. There were in significant (p < 0.05) difference of surface roughness of each brands. The results showed that the four manufactures NiTi archwires were different in grain size, wire surface and surface roughness. During clinical application, these archwires may exhibit different mechanical properties, such as strength, hardness, ductity, and friction because of their microstructure.

The Cutting Speed Influences on Tool Wear of ZTA Ceramic Cutting Tools and Surface Roughness of Work Material Stainless Steel 316L during High Speed Machining

2016 ◽  
Vol 840 ◽  
pp. 315-320 ◽  
Author(s):  
Afifah Mohd Ali ◽  
Norazharuddin Shah Abdullah ◽  
Manimaran Ratnam ◽  
Zainal Arifin Ahmad
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Tool Wear ◽  
High Speed ◽  
Dense Body ◽  
Cutting Speed ◽  
Optical Microscope ◽  
Stainless Steel 316L ◽  
Crater Wear ◽  
Matlab Programming

The purpose of this research is to find the effects of cutting speed on the performance of the ZTA ceramic cutting tool. Three types of ZTA tools used in this study which are ZTA-MgO(micro), ZTA-MgO(nano) and ZTA-MgO-CeO2. Each of them were fabricated by wet mixing the materials, then dried at 100°C before crushed into powder. The powder was pressed into rhombic shape and sintered at 1600°C at 4 hours soaking time to yield dense body. To study the effect of the cutting speed on fabricated tool, machining was performed on the stainless steel 316L at 1500 to 2000 rpm cutting speed. Surface roughness of workpiece was measured and the tool wears were analysed by using optical microscope and Matlab programming where two types of wear measured i.e. nose wear and crater wear. Result shows that by increasing the cutting speed, the nose wear and crater wear increased due to high abrasion. However, surface roughness decreased due to temperature rise causing easier chip formation leaving a good quality surface although the tool wear is increased.

scholarly journals Influence of Coolant Pressure Size on Surface Roughness when Stainless Steel Machining

2019 ◽  
Vol 299 ◽  
pp. 04002
Author(s):  
Robert Cep ◽  
Lenka Cepova ◽  
Cristina Stefana Borzan ◽  
Jiri Kasal ◽  
Marek Sadilek ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Pressure ◽  
Stainless Steel ◽  
Control Valve ◽  
Pressure Control ◽  
Optical Microscope ◽  
Contact Method ◽  
External Cooling ◽  
Pressure Control Valve ◽  
Valve Housing

The paper is focused on the influence of the coolant pressure on the surface roughness of the workpiece when machining stainless steels. The components were machined on a STAR SR-32J dual spindle machining center and an external cooling unit HYTEK CHAV 160/150-AF-F-OL was used for cooling. Two stainless steel components were investigated, namely the gas control valve rod and the high-pressure control valve housing, which require low roughness Ra after machining (less than 0.375 and 0.25 micrometers respectively). The first component was tested at 8 different pressures in the range of 150 bar - 10 bar and the second component at 4 different pressures in the range of 120 bar - 10 bar. The roughness parameters were measured by the contact method using the MITUTOYO Surftest SJ-410 Roughness Tester and the Alicona InfiniteFocus optical microscope. Based on these sample input parameters, it was evaluated howmuch the pressure affects the surface quality or suggested its reduction due to the high cost of operation of the external high-pressure equipment.

SURFACE ROUGHNESS REDUCTION OF Cr-FILMS DEPOSITED FROM NOVEL DEEP EUTECTIC SOLVENT: EFFECT OF ACETYLACETONE

2019 ◽  
Vol 26 (02) ◽  
pp. 1850150 ◽  
Author(s):  
AZEEZ ABDULLAH AZEEZ BARZINJY
Keyword(s):  
Surface Roughness ◽  
Surface Structure ◽  
Composite Films ◽  
Deep Eutectic Solvent ◽  
Optical Microscope ◽  
Organic Additive ◽  
Nickel Substrate ◽  
Average Roughness ◽  
Initial Deposition ◽  
The Impact

The surface roughness growth of electrodeposited chromium films was investigated with a particular focus on the impact of water and an organic additive, acetylacetone, on the surface roughness scaling, the surface morphology, and microstructure. Cr-composite films were prepared by new deep eutectic solvent and deposited on Nickel substrate utilizing the electrodeposition technique. Acetylacetone sources enhanced nucleation at the initial deposition stage, and the surface roughness of the films was reduced noticeably. The surface structure was studied by profilometry and 3D optical microscope. The low average roughness values ([Formula: see text]1.5[Formula: see text][Formula: see text]m) are achieved by adding water and acetylacetone, utilizing the novel ionic liquid. The most significant of the outcomes are associated with the role of water and acetylacetone which gives a reduction not only in [Formula: see text] but also in [Formula: see text] and [Formula: see text]. The obtained outcomes are promising for Cr electrodeposition, which are capable of yielding hard chromium coatings with enhanced surface structure.

Corrosion of Glazes Coated with Functional Films in Detergent Solutions

2006 ◽  
Vol 45 ◽  
pp. 156-161 ◽  
Author(s):  
Minna Piispanen ◽  
Linda Fröberg ◽  
Thomas Kronberg ◽  
Sami Areva ◽  
Leena Hupa
Keyword(s):  
Surface Roughness ◽  
Everyday Life ◽  
Surface Topography ◽  
Chemical Resistance ◽  
Sol Gel ◽  
Optical Microscope ◽  
Alkaline Environments ◽  
Zirconia Films ◽  
Excellent Chemical ◽  
Detergent Solutions

The goal of this work was to establish the compatibility of mat glazes with functional films known to render the surfaces with self-cleaning or easy-to-clean properties. Glazes with wollastonite, pseudowollastonite, diopside and zircon as the main crystalline phases in the surfaces were coated with fluoropolymer as well as ceramic, sol-gel derived titania and zirconia films. The glazes were soaked in typical detergent solutions used in everyday life up to four days. The surface roughness was measured with confocal optical microscope and the surface was imaged and analyzed with SEM/EDXA. When applied on wollastonite and pseudowollastonite containing glazes the functional films readily reacted in water solutions by pitting of the surface in the vicinity of the crystals. The ceramic titania and zirconia films showed better chemical resistance on wollastonite –free glazes, while the fluoropolymer film corroded in the most alkaline environments. The results indicate that functional films could be used also on rough surfaces without markedly affecting the surface topography. However, the films should be applied only on glazes with an excellent chemical resistance.

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