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The objective of this study was to propose a standardised methodology for assessing the accuracy of three-dimensional printed (3DP) full-arch dental models and the impact of storage using two printing technologies. A reference model (RM) comprising seven spheres was 3D-printed using digital light processing (MAX UV, MAX) and stereolithography (Form 2, F2) five times per printer. The diameter of the spheres (n = 35) represented the dimensional trueness (DT), while twenty-one vectors (n = 105) extending between the sphere centres represented the full-arch trueness (FT). Samples were measured at two (T1) and six (T2) weeks using a commercial profilometer to assess their dimensional stability. Significant (p < 0.05) contraction in DT occurred at T1 and T2 with a medium deviation of 108 µm and 99 µm for MAX, and 117 µm and 118 µm for F2, respectively. No significant (p > 0.05) deviations were detected for FT. The detected median deviations were evenly distributed across the arch for MAX at <50 µm versus F2, where the greatest error of 278 µm was in the posterior region. Storage did not significantly impact the model's DT in contrast to FT (p < 0.05). The proposed methodology was able to assess the accuracy of 3DP. Storage significantly impacted the full-arch accuracy of the models up to 6 weeks post-printing. [ABSTRACT FROM AUTHOR]

Hyperspectral remote sensing is an important earth observation method with wide application. But the low spatial resolution of hyperspectral images makes it difficult to distinguish the ground objects. The hyperspectral image unmixing is a task to estimate the spectral signatures and corresponding fractional abundances. However, the unmixing speed and efficiency are still limited by traditional structures. In this paper, a novel multilayer nonnegative matrix factorization framework is proposed with Hoyer's projector, called HP-MLNMF. The well-known framework, multilayer nonnegative factorization (MLNMF), is completely restructured and enhanced by introducing the Hoyer's projector to provide the iteration directivity of the structure in the unmixing process. Besides, a novel sparse constraint to spectral signatures suitable for this structure is found as l 1 / 4 -norm based on some experimental discussions. Moreover, the l p -norm is utilized to find the possible sparest solution for abundance terms. Finally, HP-MLNMF is compared with some representative and state-of-art methods on synthetic and real-world hyperspectral image datasets. Experiments indicate that our method performances well in most cases. [ABSTRACT FROM AUTHOR]

In food packaging, low-density polyethylene (PE) coating is applied to paperboards to act as a functional barrier and to provide the smoothness required to enhance printability. These characteristics are related to the material's surface roughness, the parameter monitored during the manufacturing process. Measurement of surface roughness using optical profilometry has gained importance in the paper industry. The optical instruments used to measure surface roughness are limited spatially by the relationship with the light wavelength at which they operate. A scanning electron microscope (SEM) is an alternative for overcoming the spatial resolution limitation, and the use of stereo-photogrammetry on SEM images can be seen as an alternative profilometry technique to measure surface roughness. In this investigation, the surface topography of industrially manufactured high-quality PE-coated paperboard was studied, comparing the SEM stereo-photogrammetry technique with a reference profilometry method, i. e., chromatic confocal microscopy (CCM). We found close agreement between the calculated surface roughness and the results of the techniques used and compared them according to the new ISO 25178 Geometric Product Specifications. We concluded that SEM stereo-photogrammetry provides comparable accurate alternative profilometry method for characterizing the surface roughness of PE-coated paperboard in the micrometer scale. [ABSTRACT FROM AUTHOR]

In the present study, laser periodic structuring of titanium-based alloy (Ti-6Al-4V) has been carried out using Ti:Sapphire laser with the wavelength of 800 nm and pulse duration of 3 ps and 100 fs with varying peak fluence and scan speed. After laser irradiation, the topography of the surface has been recorded using 3D surface profilometer. Laser surface processing leads to the formation of a periodically patterned surface with the average ablation depth of 37.25 µm-42.13 and average surface roughness of 0.991-1.862 µm as compared to 0.169 µm average roughness of as-received Ti-6Al-4V. In the microstructure, there is presence of fine periodic ripples with an average ripple width of 0.48 µm to 0.54 µm when processed with 3 ps laser and the average ripple width of 0.17 μm in addition to the presence of very fine pits, deposited particle, and oxide dispersed surface when processed with 100 fs laser. The microhardness of the surface is improved (395 VHN-373 VHN) as compared to 282 VHN of as-received Ti-6Al-4V. There is a significant improvement in the corrosion resistance in terms of a decrease in corrosion rate (0.0037 to 0.0008 mm/year) in laser surface processed sample as compared to as-received Ti-6Al-4V (0.0932 mm/year) in Hank's solution and also increase in pitting corrosion resistance in terms of increase in critical potential for pit formation (Epit) under a few employed parameters with both 3 ps laser (at a laser fluence of 0.063 J/cm2 and a scan speed of 20 mm/sec) and 100 fs laser (at a laser fluence of 0.63 J/cm2 and at a scan speed of 60 mm/sec). [ABSTRACT FROM AUTHOR]

Spatial resolution in three-dimensional fringe projection profilometry is determined in large part by the number and spacing of fringes projected onto an object. Due to the intensity-based nature of fringe projection profilometry, fringe patterns must be generated in succession, which is time-consuming. As a result, the surface features of highly dynamic objects are difficult to measure. Here, we introduce multispectral fringe projection profilometry, a novel method that utilizes multispectral illumination to project a multispectral fringe pattern onto an object combined with a multispectral camera to detect the deformation of the fringe patterns due to the object. The multispectral camera enables the detection of 8 unique monochrome fringe patterns representing 4 distinct directions in a single snapshot. Furthermore, for each direction, the camera detects two π-phase shifted fringe patterns. Each pair of fringe patterns can be differenced to generate a differential fringe pattern that corrects for illumination offsets and mitigates the effects of glare from highly reflective surfaces. The new multispectral method solves many practical problems related to conventional fringe projection profilometry and doubles the effective spatial resolution. The method is suitable for high-quality fast 3D profilometry at video frame rates. [ABSTRACT FROM AUTHOR]

In this article, a surface inspection system for rails is presented. Rails must meet the strict requirements of international quality standards; however, there are few commercial surface inspection systems for rails and also a lack of publications describing the design and configuration of inspection systems in detail. Therefore, manufacturers must develop their own systems or buy one of the few commercial ones available. These systems also need a long, cumbersome, and expensive configuration process that the manufacturer cannot perform without the assistance of the inspection system provider. The system proposed in this article needs a set of samples and the requirements of the international standards to carry out an automatic configuration process avoiding the cost of manual configuration. The system uses four profilometers to acquire the surface of the rail. The acquired data is compared to a mathematical model of the rail to generate differential topographic images of the surface of the rail. Then a computer vision algorithm is used to detect defects based on the tolerances established in the international quality standards. The system has been tested and validated using a set of rails and a rail pattern from ArcelorMittal, with better results than the other two systems installed in a factory.1 [ABSTRACT FROM AUTHOR]

The aim of this work was to the investigate two-body wear behavior of zirconia-reinforced lithium silicate glass-ceramic and composite resins through in vitro chewing simulation. Two types of glass-ceramics (IPS e.max CAD; lithium disilicate, Vita Suprinity; zirconia-reinforced lithium silicate) and two types of composite resins (Filtek Supreme; nano-filled, Ivoclar Vivadent Heliomolar; micro-filled) were used. All specimens were exposed to two-body wear tests using a dual-axis computer-controlled chewing simulation. Each chewing simulation test procedure, Al2O3 ball with a diameter of 6 mm, was used as antagonist material. The mean volume loss and wear depth of all specimens after the chewing tests were determined with use non-contact 3 D profilometer. Zirconia-reinforced lithium silicate Vita Suprinity had significantly higher two-body wear resistance than lithium disilicate IPS e.max CAD glass-ceramic and other composite resins after chewing tests. While Vita Suprinity exhibited a homogeneous crystal microstructure, IPS e.max CAD glass-ceramic exhibited a structure with needle-shaped fine-grained crystals embedded in a glassy matrix. As a result, the homogeneous distribution of zirconia particles into the ceramic material will increase the two-body wear resistance through chewing simulation tests. [ABSTRACT FROM AUTHOR]

Intraoral scanners (IOS) have been used to quantify tooth wear, but so far they have not been systematically validated for monitoring of tissue loss. The aim of this in vitro study was to investigate whether progression of tissue loss can be detected with an IOS and whether IOS values agree with those obtained with noncontacting profilometry (PRO) serving as a standard method. Model jaws were mounted in a phantom head positioned in a dental chair. Flattened areas were prepared on the non-load-bearing cusps of the first molars (model teeth; n = 16) in order to fix flat enamel samples with an experimental area and a reference area. After baseline PRO and IOS, the experimental enamel area was stepwise etched with 35% H3PO4 gel (4 × 30 s and 4 × 15 s). After each etching, PRO and IOS was performed and the vertical tissue loss between the reference and experimental areas was measured, each at the same 3 measurement points. Furthermore, cupped cusps were simulated by stepwise preparation of the load-bearing cusps of the model teeth with a spherical diamond bur, and the maximum vertical depth after each preparation step was measured only by IOS. Trios3 (3Shape, Denmark), Carestream CS3600 (Carestream, USA) and an optical profilometer (MicroProf, Fries, Germany) were used to measure the flat areas of the enamel samples, whereas only IOS were used to measure curved surfaces on the load-bearing cupped cusps of the model teeth. The IOS data were analyzed with an external software (GOM Inspect, Germany) and with the respective internal IOS software. PRO revealed a mean (±SD) tissue loss of 17.1 ± 4.7 µm after 30-s etching steps and 10.1 ± 5.1 µm after the 15-s etching steps. IOS and software types were able to detect the progression of tissue loss after each etching step (p ≤ 0.001 each); Bland-Altmann plots revealed good agreement with PRO regardless of the order of tissue loss, and no systematic difference was found. Increasing cupped lesion depths were detected by all IOS, with no significant differences between IOS and analysis methods. IOS were able to detect small amounts of tissue loss under simulated clinical conditions and seem to be a promising tool for monitoring even initial erosive tooth wear. [ABSTRACT FROM AUTHOR]

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The friction between natural fibers and metal affects tool life, wear and tear and surface defects of extrudates. The ability of alkyl ketene dimer (AKD) and magnesium stearate (MgSt) to reduce coefficient of friction (COF) between thermomechanical pulp (TMP) and metal were determined at temperatures of 30, 100, and 180 °C and additive concentrations from 0.5 to 5 wt%. The AKD and MgSt were added to TMP sheets through spraying, followed by drying. ATR-FTIR and IR microscopy confirmed the presence of AKD and MgSt on the TMP. AKD addition at 2 wt%, consistently reduced the COF of TMP and metal, whereas MgSt reduced COF at 100 and 180 °C, only. No further reduction in COF was observed at 5 wt% of AKD or MgSt. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the effect of cigarette smoke on the surface roughness of two commercially available denture base materials. Materials and Methods: A total numbers of 40 specimens were fabricated from two commercially available denture base materials: heat-cured polymethylmethacrylate and flexible denture base materials (20 for each). The specimens for each type were divided into four subgroups: subgroup I, heat-cured denture base material specimens (control group); subgroup II, flexible denture base material (control group); subgroup III, heat-cured denture base material specimen exposed to cigarette smoking group; and subgroup IV, flexible denture base material specimens exposed to cigarette smoking. The control groups were used for immersion in distilled water, and the smoke test groups were used for exposure to cigarette smoking. The smoke test group specimens were exposed to smoking in a custom-made smoking chamber using six cigarettes for each specimen. The surface roughness was measured using a profilometer, and the measurements were considered as the difference between the initial and final roughness measured before and after smoking. Paired t test and independent t-test were used to interpret differences in initial and final roughness values within and between groups respectively. Results: Paired t-test showed a significant difference between initial surface roughness and final surface roughness within each subgroup. Conclusion: The surface roughness of the specimens fabricated from the flexible denture base material was found to be more compared to heat-cured denture base specimens after exposure to cigarette smoke.

Aim: The aim of this study was to evaluate the effect of glazing, reglazing, and chairside polishing on the surface roughness of dental porcelain. Materials and Methods: A total of 50 discs of feldspathic porcelain were fabricated using a metal mold of dimension 10 mm × 2 mm. Based on the surface treatment, the samples were divided into five groups. Group A – Glazed (control), Group B – Abraded and reglazed, Group C – Abraded and polished with porcelain adjustment kit (Shofu Dental Corp. PN 0301 Classic Plastic HP Kit, Shofu Inc., Kyoto, Japan), Group D – Abraded and polished with diamond polishing paste (Shofu Dental Corp. PN 0558 DirectDia, Shofu Inc., Kyoto, Japan), Group E-Abraded and polished with the combination of porcelain adjustment kit followed by diamond polishing paste. The surface roughness (Ra) values (μm) were evaluated by a profilometer (Mitutoyo Surftest SJ-310, Tokyo, Japan). The data obtained were statistically analyzed using one-way ANOVA and post hoc Tukey's test. Results: The mean surface roughness (Ra) of Groups A, B, C, D, and E was 0.567 ± 0.078 μm, 0.433 ± 0.059 μm, 0.882 ± 0.126 μm, 2.361 ± 0.195 μm, and 0.438 ± 0.043 μm, respectively. The samples of Group D (Polished with polishing paste alone) had the highest surface roughness (Ra value). Whereas the samples of Group B and E had similar surface roughness (Ra) value. Differences between Groups A, B, and E were statistically insignificant (P > 0.05). Conclusion: After adjustment of ceramic restorations in dental clinics, diamond polishing paste, when used after porcelain adjustment kit, could provide the marked finish equal to glazed or reglazed surface. [ABSTRACT FROM AUTHOR]

: Background: Abrasives are the insoluble components added to dentifrices to aid the physical removal of stains, plaque and food debris. However, replete of abrasivity cause enamel abrasion, dentin hypersensitivity, damaging the smile as well as masticatory apparatus. The aim of this study is to evaluate the enamel surface abrasivity using three different herbal dentifrices and a customised brushing machine under profilometer. Materials And Method: A total of 30 enamel blocks are prepared from buccal surface of maxillary central incisor which are randomly divided into three groups. Group-1 Specimens brushed with Colgate Vedshakti, Group-2 Specimens brushed with Patanjali Dant Kanti, Group-3 Specimens brushed with Dabur Red. All specimens were brushed using a customised brushing model with Oral-B powered brush for 30 minutes. Surface roughness of all three groups specimens were analysed using a surface roughness tester-profilometer. Statistical analysis used in this study was one-way analysis of variance (ANOVA) followed by post hoc turkey’s test. Results: Statistically significant difference was observed in value of enamel abrasion amongst Group1, 2 and 3. (p<0.05) Conclusion: Toothpaste with higher relative enamel abrasivity has the potential to abrade the enamel and cause hypersensitivity. The least enamel abrasion was observed in Colgate Vedshakti when compared with Patanjali Dant Kanti and Dabur Red toothpaste. [ABSTRACT FROM AUTHOR]

We considered Class II dental cavities in critical tooth areas concerned with vital pulp therapy, and evaluated the marginal gap after treatment with Biodentine and Geristore, and one composite after either etching and adhesive (V2) and after use of a self-etching system (iBond Universal). We measured the surface morphology at the marginal gap by optical profilometry, and carried out analysis of the 3D data according to a new effective definition of marginal gap. The defined quantity was assessed for statistical significance of the apparent differences. The largest gaps appeared for Geristore (first) and Biodentine (not significantly lower), whereas the gaps of the composite controls were both lower, the lowest being the two-step self-etched system with respect to the three-steps etched and adhesive system, yet without statistical significance. Obviously, there is still room for improvement of the vital pulp therapy restorative materials, as compared to the use of standard composite systems. [ABSTRACT FROM AUTHOR]

Background: Adequate plaque control facilitates good gingival and periodontal health, prevents tooth decay, and preserves oral health. Toothbrushing is the primary method of removing plaque and can be classified into powered and manual toothbrushes. Aim: The primary objective was to compare the abrasiveness and surface roughness caused by four different power-driven toothbrushes with a different mode of action, on tooth surfaces in vitro. Materials and Methods: An in vitro experiment was conducted on eighty freshly extracted tooth specimens which were equally divided into four groups. Each group was brushed with the specifically assigned electric toothbrush to that group, but keeping parameters such as force applied during brushing, storage of tooth before and after brushing, and toothbrushing time same. A total of the 2-month study was done on each tooth specimen. Tooth surface roughness was recorded before and after the toothbrushing experiment to check the difference between surface roughness readings. Scanning electron microscopic (SEM) analysis was done afterward to analyse the surface topography of each group specimens. Statistical Analysis Used: Paired t-test used for intergroup analysis and intragroup analysis was done using Kruskal–Wallis test. Results: After comparing the baseline and final readings of each group, it has been found that the mean difference between values is highly significant in Group 1 (rotary/oscillatory). The mean rank of Group 1 was least in all four groups, which showed the highest tooth surface abrasion in that group. SEM analysis also revealed that Group 1 tooth specimens had deeper scratches/lines comparatively to other groups. Conclusion: Rotary/oscillatory toothbrush caused the highest tooth surface abrasion when compared with other electronic toothbrushes. [ABSTRACT FROM AUTHOR]

Given that the ballscrew raceway profile directly affects the service characteristics and precision retention of ball screws, this paper proposes an optimized continuous measuring method for the ballscrew raceway profile, without the need to adjust the sensor for the measurement of each raceway. Based on a comparison with existing measuring methods and principles, an optical measuring system is constructed, in which installation errors in the LED sensor and the linear calibration system, together with the straightness of the mobile platform, are obtained and analyzed. More importantly, in this work, we propose a transformation algorithm for the helix angle as well as an arc-selecting principle. Compared to the measurment results and time consumption of the profilometer, the maximum error for the measured radius and contact angle of the system proposed in this paper is 1.5 μm and 35′, and the measuring efficiency is increased by 15.8%, 58.6%, and 67.5% for 1, 5, and 20 continuous raceways, respectively, indicating effective performance in terms of accuracy, repeatability, and efficiency. Moreover, the system is also capable of measuring the pitch diameter and lead error of the ballscrew, which is significant in regard to classifying the accuracy of the ballscrew raceway profile, and improving machining precision. [ABSTRACT FROM AUTHOR]

This paper proves that die-sinking electrical discharge machining (EDM) is an alternative and attractive manufacturing method of producing cardiovascular stent. This study investigates the effect of pulse currents on the material removal rate (MRR), the surface of EDM, and the upper surface of the strut stent. The observed surface characteristics of the strut were surface roughness, recast layer, and the diameter of the crater. The recast layer and crater were analyzed by an optical microscope, and the surface roughness was measured by a surface profilometer. The pulse currents which were used in the manufacturing of stent by die-sinking EDM were 1.5 A/45 μs, 3.0 A/90 μs, 4.5 A/120 μs, and 6 A/150 μs. The experiment shows that the stent is successfully manufactured from minitube AISI 316L by die-sinking EDM. The diameter, length, and thickness of the stent are 4 mm, 20 mm, and 0.3 mm, respectively. The results show that increasing of pulse current will cause the increase of MRR, the thickness of recast layer, the surface roughness, and the crater diameter. The MRR, thickness of the recast layer, surface roughness, and crater diameter are also influenced by the pulse on time. The EDM surface roughness, the average thickness of recast layer, and the diameter of crater are in the range of 3.49–9.53 μm, 17.6–97 μm, and 75.84–276.5 μm, respectively, and the upper surface roughness of the strut is 0.5534 μm. The best quality of the strut is generated from the pulse current 1.5 A/45 μs. [ABSTRACT FROM AUTHOR]

An experimental solid particle erosion study was conducted to investigate the erosion of silicon nitride at different angles of attack using optical techniques. During the erosion process, it has been noticed that when silicon carbide abrasive particles came into contact with the target material, a shower of sparks was created due to the high heat generated causing localized melting on the surface of the abrasive particles. Shadow Moiré, an inexpensive and easy-to-setup technique, was then used to estimate the depth, width, and circularity of the erosion scars. The same parameters were also measured using a non-contact optical profilometer to evaluate the accuracy of shadow moiré technique. A good agreement has been observed where the shadow moiré technique was capable of estimating the circularity, maximum depth, and the width to depth ratio of the erosion scars with a maximum error of 15%, 16%, and 12%, respectively. [ABSTRACT FROM AUTHOR]

Anatase-phased TiO2 films were prepared at different temperatures (350, 400, 450 and 500∘C) using automated nebulizer spray pyrolysis (ANSP) method. The structural study (XRD) revealed the amorphous nature at 350∘C and remaining samples (400, 450 and 500∘C) show the tetragonal structure with 2 θ ∘ = 2 5. 7 8 , 38.43, 48.49 and 55.54 corresponding to (101), (004), (200) and (105) reflected planes and it is well fitted with standard data. The compositional XPS analysis confirmed the core level primary element of Ti 2p, O 1s and valance band (VB) of Ti 3p, Ti 3s, O 2s peaks in the prepared samples. The 3D optical profilometer has shown that the thickness of the prepared films was decreased by increase in temperature. The AFM study exhibited average roughnesses (Ra) of the prepared films such as 0.058, 0.147, 0.176 and 0.194 nm, respectively. The surface morphological study of FESEM has shown the cracked uneven distributed nature (350∘C) turn into evenly distributed closed packed agglomerated particles by the influence of temperature. The oscillating nature of transmittance (%) with redshift of the sharp absorption edge was observed in UV–Vis–NIR spectrophotometer and found the bandgap value about 3.58 eV to 3.33 eV through Tauc's relation. The gas-sensing behavior has shown better response to C2H6O reducing gas at 300∘C operating temperature with 150 ppm gas concentration. [ABSTRACT FROM AUTHOR]

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Contact stylus profilometry is the leading surface texture measuring method in many manufacturing industries. For years it has been unmatched in terms of accuracy and reliability. Advancements in technology have led to the improvements in the profilometer design. A stylus can either have a built in skid or be skidless. In this study, the influence of skid on the measurement accuracy and repeatability was evaluated. Four different contact stylus profilometers were used to measure three standard roughness artifacts each. Every set of measurements consisted of 50 repetitions of the same profile, with the same parameters. Out of these profiles, five roughness parameters were calculated and were subjected to a statistical analysis. Relative errors of these parameters were also considered and presented individually for each roughness standard. Researchers found differences in the measurement results dispersion of various roughness parameters between the three roughness standards. The presented results of the measurements clearly indicated that there is a dispersion of the obtained values for the older type of contact stylus profilometer (P1, skid). The skidless portable devices, P2 and P3, have better measurement resolution, which results in a noticeably lower dispersion of measured values. A tabletop, stationary device utilizes a skidless measuring probe. It has both the best resolution and the highest rigidity, which results in the lowest dispersion of measured values. The lowest relative error of the Ra parameter was determined for the P2 device (9.2%) and the highest was determined for the P3 device (72.6%). [ABSTRACT FROM AUTHOR]

The composition, operating principle, and basic metrological characteristics of GET 186–2017, the State Primary Standard of units of ellipsometric angles, a Standard that supports measurement of the two-dimensional spatial distribution of ellipsometric angles, are described. The structure of GET 186–2017 includes a spectral ellipsometer equipped with a x, y-stage for measurements on a grid of 10 × 10 points and an interference profilometer by means of which a two-dimensional map of deviations from 90° of the normals to the surface of an object may be measured. Measurements are not performed at scanning points where the deviation of the normal exceeds 0.01°. Through measurement of the two-dimensional spatial distribution of ellipsometric angles it is possible to establish the spatial distribution of the thickness and complex indicator of refraction of the coatings across the area of a test article. GET 186–2017 supports the uniformity of measurements in highly important trends in science and technology, such as microelectronics, optics, and instrument construction. The principal users of GET 186–2017 are organizations involved in the development of new articles in microelectronics, solar batteries, and optics, in particular, laser gyroscopes. Ordered multilayer structures deposited on a substrate where the thickness of these structures is monitored by means of different types of ellipsometers, including image ellipsometers, are components of such structures. [ABSTRACT FROM AUTHOR]

Purpose: The carbon/carbon (C/C) composite finger seal experiment was performed on a high-speed seal tester. The purpose of this paper is to investigate the leakage and wear characteristics of C/C composite finger seal under various operating conditions. Design/methodology/approach: Static, dynamic, endurance and post endurance tests were carried out. For static and performance tests, the pressure differential changed from 0.1 to 0.6 MPa and the rotor speed varied from 1,000 to 9,000 r/min. Two endurance tests were conducted for 4 h, with each mounting two finger seals. The seal leakage was monitored by mass flowmeters, and the wear depth was measured and calculated by using three-dimensional profilometer. Findings: Results showed that the seal leakage increases with pressure differential but decreases with rotor speed. Leakage rate is lower when speed is decelerated than that with the speed stepped up. During a time history, material removal caused by wear has significant influence on leakage data causing higher leakage than the results before endurance test. Particular interest is that the uneven wear characteristic on finger foot bottom was firstly revealed, showing severe wear in foot heel area than that in foot toe. Originality/value: This study could provide experimental guidance for finger seal designers. Additionally, the uneven wear characteristic of finger foot was firstly revealed, which showed the necessity of further theoretical research on finger seal wear. [ABSTRACT FROM AUTHOR]

This work has described about the generation of complex shaped pattern using reverse electro discharge machining process. Powder metallurgical green compact tool has been used to generate a predefined pattern by depositing its constituent materials. A predefined star shaped pattern has been generated on the aluminum 6061 work surface. The pattern has been created by adjusting the process factors like compact load, current and pulse duration. The edge deviation and surface roughness have been considered as the performance measures in this experimentation. An optimum condition has been obtained at compact load of 20 tons, current of 1 A and pulse duration of 100 µs. Minimum surface roughness of 1.7 µm and minimum edge deviation of 13.07 µm have been achieved at this condition. The patterns are characterized by SEM, EDS and XRD analyses. The surface of the patterns is evaluated by a surface profilometer. The layer thickness is evaluated by an optical microscope. The microhardness of newly generated surface of pattern has been found to be of 329 Hv. [ABSTRACT FROM AUTHOR]

Stainless steel has been used as a successful biomaterial for decades. In this study, a pulsed nanosecond laser was used to create patterned surfaces of stainless steel coupons to study the effect of patterning on fluid retention and biocompatibility studies of laser patterned and control surfaces. An AVIA 355 nanosecond pulsed laser was used with different laser parameters to create unique "peak and valley" structures (uniform textured surface) on stainless steel coupons of size of 1 x 1 x 0.1 cm³. The surface structural changes can be attributed to the Gaussian beam profile of the laser. The coupons were observed under a scanning electron microscope to understand the change of the material surface profile. An optical profilometer was used to measure the surface roughness and compare it with a nontextured or control surface. The contact angle measurement showed a decrease in the contact angle, reduced to 71.6° from 82.2° making the patterned surface more hydrophilic. A biocompatibility study of the stainless steel was performed to evaluate the effect of surface modification on its impact on biocompatibility. The cell viability of the patterned sample was 94% as compared to 84% for the unpatterned surface. A simulation of the process was run using FLOW3D® to understand the behavior of the material during the texturing process. The results obtained from the simulation process were compared with the experimental data and found to be in good agreement. The effects of Gaussian beam, vapor pressure, and overlapping of the beam were also analyzed in the simulation process. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to compare color stability and surface topography of two different feldspathic porcelains, both qualitatively and quantitatively, after exposure to routinely consumed beverages over different time periods using a spectrophotometer and surface noncontact profilometer, respectively. Materials and Methods: In this in-vitro study, a total of 120 base metal alloy discs with a thickness of 0.5 mm were made following the conventional casting technique. They were randomly divided into two categories. Category-I was built with IPS.d.Sign (Ivoclar), Category-II was built with Ceramco 3 (Dentsply) each containing 60 samples. The samples were immersed into different beverages. Color stability and surface roughness were measured by a spectrophotometer and profilometer, respectively. Statistical Analysis: t-test between two categories and ANOVA within the same group. Results and Conclusion: Color difference (ΔE) between different test solutions at different intervals showed clinically acceptable range (below 3.3 units). Thus, ceramics were considered color stable and resistant to external staining. Scanning electron microscope and profilometer study revealed that there were significant surface roughness changes in both IPS.d.Sign and Dentsply metal ceramic materials when immersed in soft cola drink and coffee solutions for 90 days and compared to the control group which was immersed in distilled water.

Context: Long-term retention of the restoration depends on strength and durability of the bond of the luting composite resin to the tooth and the porcelain substrates. Aims: This in vitro study was conducted to compare and evaluate the influence of hydrofluoric acid (HF) and acidulate phosphate fluoride (APF) gel-etched treatments on surface roughness and bond strength to dentin of a commercially available lithium disilicate ceramic (E-Max). Subjects and Methods: Sixty lithium disilicate ceramic disks measuring 5 mm in diameter and 2 mm thick were fabricated and divided into three groups: Group A (n = 24), Group B (n = 24), and Group C (n = 12) and were subdivided to Group A1, A2, and A3which were surface treated with 1.23% APF gel (pH = 3–4) at different time intervals 4, 7, and 10 min, respectively. Group B1, B2, and B3 were surface treated with 1% APF gel (pH = 1–2) at different time intervals 4, 7, and 10 min, respectively. Group C were surface treated with 9.6% HF (pH = 1–2) for 1 min. Morphological changes obtained with the surface treatments were analyzed using a surface profilometer. Statistical Analysis: All specimens were subjected to a tensile bond strength test using a tensometer, and the obtained data were statistically analyzed using Kruskal–Wallis test. Results: The surface roughness (μm) and bond strength (MPa) of lithium disilicate discs (samples) etched with 1.23% APF gel and 1% APF gel for 10 min and etched with 9.6% HF for 1 min showed no statistical significant difference among them. Conclusions: In this study, the lithium disilicate discs etched with 1.23% APF gel and 1% APF gel for 10 min showed similar surface roughness and bond strength to those etched with 9.6% HF for a minute.

The presented work attempts at determining the effect of the parameters of the nickel coating process with the galvanic method i.e. current density, time and temperature, upon the quality of the coatings obtained.

The effect of surface roughness on the thermohydraulics in minichannels has been studied numerically. Fluid flow (at low Reynolds number) through a typical three-dimensional (3D) channel subjected to constant heat flux (at the bottom) is analyzed incorporating surface roughness on the solid-fluid interfaces characterized by its true random and nonperiodic nature. Two different approaches are adopted to model the rough channel surfaces. Topographic measurements have been performed on a stainless steel minichannel using an optical surface profilometer (OSP) to generate digital replica of the rough surface. Alternatively, the Gaussian function defined by two statistical parameters, namely average roughness (Ra) and correlation lel)⁠, are employed to imitate the random nature of rough interface. At the outset, conjugate heat transfer simulations have been performed on the rough channel models and the results are validated against the experimental data. Finally, the effect of surface roughness on both local and global nondimensional performance parameters is analyzed and compared with findings from simulations performed on a similar smooth channel. The outcomes reveal an enhanced friction factor for flow over a rough surface, attributable to the near wall shear rate fluctuations experienced by the flow. Unlike smooth channels, the local Nusselt number (Nuy) exhibits continuous fluctuations along the channel axial length. The fully developed (Nufd) and the average (Nu) counterparts of the Nusselt number show enhanced magnitudes when compared to the theoretical predictions of the same in a smooth surface channel. This amplification can be attributed to two simultaneously acting factors: augmentation in heat transfer area and chaotic mixing due to flow perturbation. The magnitude of enhancement in terms of fully developed Nusselt number (Nufd) is roughly 1.3 times of its corresponding value in a smooth channel and the factor remains invariant of the supplied heat. [ABSTRACT FROM AUTHOR]

Fluid flow through three natural single rough-rock fractures were measured at different normal stresses. The surface height of both halves of each of these fractures was measured with and without solidified Wood's metal filling using a laser profilometer to calculate the aperture distribution of the three fractures under different normal stresses. The flow calculated for the three fractures according to the sample scale cubic law using the mean apertures overestimated the experimental flow by 2.5–342 times, within a normal stress range of 0–8 MPa. The elementally applied cubic law (EACL) through a finite-element model also overestimated the experimental flow by 2.0–117 times within the same normal stress range. As the normal stress applied on a natural rough-rock fracture increases, the overestimation increases due to increasing contact areas and increasing tortuous behavior of flow. At the sample scale, mean apertures to the powers between 4.03 and 6.47 were required for the three fractures to produce the experimental flows in the same normal stress range. At the FEM elemental scale, apertures to the powers between 3.65 and 5.74 were required for the three fractures to produce experimental flows in the same normal stress range. The required aperture to the power to produce experimental flow was found to increase with increasing normal stress. These findings clearly show the inapplicability of the cubic law to estimate flow through natural rough-rock fractures, especially under high normal stresses. [ABSTRACT FROM AUTHOR]

Aims & Objectives: The aim of the study was to evaluate and compare dimensional accuracy, surface characteristics and load deflection attributes of SS wires sourced from six different commercial houses. Materials & Methods: 0.019" x 0.025" SS wire samples were divided into 6 groups and evaluated and compared for the aforementioned properties. Dimensional accuracy, surface roughness, frictional resistance, load deflection rate and ultimate tensile strength were evaluated and compared. Results: Dimensional accuracy did not vary significantly. Surface Profilometry proved 3M Unitek (Group 1) to be the wire with least irregularities. According to SEM, Modern Orthodontics (Group 6) and 3M Unitek (Group 1) in terms of 'Sa' and 'Sq' respectively had the smoothest surface finish. SS wires sourced from G&H Orthodontics (Group 2) exhibited least frictional resistance. Load deflection rates varied for all the groups for all three parameters under the study. UTS was best for SS wires sourced from Rabbit Force Orthodontics (Group 5). Conclusion: No wire from a single commercial house excels in all the parameters that were evaluated, each one having its aces and minuses. [ABSTRACT FROM AUTHOR]

The paper shows the construction and control of a climatic chamber used for the credibility evaluation of the profilometic measurements. The paper presents a control model using a PID controller and a solution for air circulation. The data regarding the influence of environmental temperature changes on the three-dimensional representation of the surface realized by means of a tactile profilometer were presented. This work shows the temperature characteristics of a climatic chamber. [ABSTRACT FROM AUTHOR]

The aim of our study was to analyze the precision of fused-deposition modeling (FDM), polyjet technology (PJ), stereolithography (SLA) and selective laser sintering (SLS) and to evaluate some interesting indications of these methods in clinical practice. Forty upper dental arches were scanned using a 3Shape Trios 3R optical scanner system and 3D models were made. An Atos II 400 optical 3D scanner was used for calculating the coordinates of points by optical triangulation, photogrammetry and fringe projection. Each model was scanned from a minimum of 56 positions to evaluate global coordinates. Surface morphology was evaluated with an Alpha Step IQ profilometer and a JSM 5510 LV scanning electron microscope. From the measurements in cross-sections it was evident that the deviation shifted by approximately 0.1 mm. The smoothest and most homogeneous sample was SLA. SLS and SLA samples showed the most similar results in comparison of perpendicular directions (homogeneity). FDM and PJ materials exhibited significantly greater roughness in the printing direction than in the perpendicular one, which is most likely caused by the technology selected and/or print parameters. Clinical applications have demonstrated unusual treatment options for patients with rare diseases. [ABSTRACT FROM AUTHOR]

This work presents an improved method for the measurement of the rolling bearing torque loss using a modified Four‐Ball machine. The new assembly allowed precise and accurate rolling bearing torque loss, while operating at constant temperature, controlled by means of liquid cooling‐heating system in which a thermal fluid is carried through the centre of the driving shaft. Several rolling bearing test campaigns are performed, using a fully formulated ISO VG 150 poly‐α‐olefin gear oil. The frictional torque loss is measured and compared with models available and the surface roughness of the rolling bearing races is observed using an optical profilometer. [ABSTRACT FROM AUTHOR]

Data on the waviness of a processed part related to the coordinate system associated with the laser treatment bench used with a surface are needed to increase the effectiveness of the technology of laser destructuring. At the present time, there are no contactless topographic measurement instruments that meet all the requirements that are imposed on the system used in measurement of the profile of the surface of parts and that are determined by the parameters of the technological process of laser destructuring. A trial design of a system for measurement of the profile of a surface (waviness) constructed according to the principle of an optical profilometer and modified in accordance with the requirements imposed on measurements performed on a laser treatment bench is created. Through the use of the system measurements of waviness are performed directly on the bench, which significantly reduces the length and difficulty of the technological process. A diagram and operating principle of the waviness measurement system on a laser destructing bench are described. A triangulation method is used in the measurements. Through the use of a trial design of the system the waviness profi le of a surface with spatial wavelength 2 mm may be measured with error 3.78 μm in the vertical direction and 13.8 μm in the lateral direction. Verification of the precision of the trial design of the system is performed by a standard method of stylus profilometry. The waviness profile of a surface obtained with the use of the trial design of the system may be used for modulation of the amplitude of the power of laser radiation in hte technological process of laser destructuring. [ABSTRACT FROM AUTHOR]

The description of detectors based on measuring the secondary-emission current and results of their tests are presented. Multichannel profilometers with a range of n × 103 to 109 ions/(cm2 s) have been created. This range is largely overlapped with the range from a few units to 106 ions/(cm2 s), which is characteristic of scintillation and semiconductor detectors. Current profilometers are used in the region of the overlap to monitor their degradation under exposure to the beam. The current profilometers are used in the transit of low-intensity beams, and their sensitivity is higher than the sensitivity of Al2O3 phosphors and Faraday cups by four orders of magnitude. A three-lamel probe has been created based on the secondary emission to measure the current of the internal accelerator beam with a lower-range value of 0.1 pA. [ABSTRACT FROM AUTHOR]

Tests were conducted to identify and understand the failure mechanisms that control a gear's longevity during a loss of lubrication (LoL) event by tracking the physical and tribological changes experienced by the gear teeth from operating without oil. A total of five tests were performed using 28-tooth, eight-pitch spur gears made from AMS 6308 on a single-mesh test rig. A new set of gears was used for each test, which consisted of run-in, failure, and matching the time of three of the inflection points present in the material's failure progression curve. The tests were performed without lubrication at 10 krpm while supporting a torsional load of 58.8 N-m. Posttest analysis included optical microscopy of the tooth surfaces and measurements of the tooth involute profile using a stylus profilometer. Results showed that any face width crowning was lost almost immediately but the involute profile remained mostly intact until the period of thermal runaway. The results also suggest that the mesh friction coefficient, material case hot hardness, and thermal expansion play a significant role in the gear's survivability, with eventual failure linked to the elimination of the available backlash. [ABSTRACT FROM AUTHOR]

A European EMPIR project, which aims to use large-scale, 5 mm × 200 µ m × 50 µ m (L×W×H), piezoresistive microprobes for contact resonance applications, a well-established measurement mode of atomic force microscopes (AFMs), is being funded. As the probes used in this project are much larger in size than typical AFM probes, however, some of the simplifications and assumptions made for AFM probes are not applicable. This study presents a guide on how to systematically create a model that replicates the dynamic behavior of microprobes. The model includes variables such as air damping, nonlinear sensitivities, and frequency dependencies. The finished model is then verified by analyzing a series of measurements. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the friction behavior of SiC-B4C composite ceramics treated by annealing in air sliding against SiC balls. Design/methodology/approach: The dry sliding tests were performed with a ball-on-disk tribometer in ambient air condition. Analysis of friction coefficient, phase compositions of the surfaces, morphologies of worn surfaces of disks and wear scars of balls and surface profiles of wear tracks for disks were carried out using Raman spectroscope, microscope and surface profilometer. Findings: The results show that a self-lubricating layer with the main composition of H3BO3 was successfully fabricated on the surface of SiC-B4C composite ceramics by the annealing treatment in air. When the mass fraction of SiC is more than that of B4C, SiC-B4C composite ceramics show higher friction coefficients, the values of which are 0.38 for 80 Wt.%SiC-20 Wt.%B4C and 0.72 for 60 Wt.%SiC-40 Wt.%B4C, respectively. SiC-B4C composite ceramics show lower friction coefficients when the mass fraction of B4C is more than that of SiC. The low friction coefficients of 40 Wt.%SiC-60 Wt.% B4C composite ceramics (0.16) and 20 Wt.%SiC-80 Wt.% B4C composite ceramics (0.20) are attributed to the formation of a sufficient amount of H3BO3 layer, rather than the layer of silicon oxides. Originality/value: This study will help to understand the friction behavior of SiC-B4C composite ceramics with different ratios of SiC to B4C treated by annealing in air. [ABSTRACT FROM AUTHOR]

Introduction: Improper finishing and polishing of composite resins always present a problem to dental practitioner. Advances in composite resin materials and the instruments used for finishing and polishing has revolutionised the art of aesthetic dentistry. This study utilises surface texture of composite resin as a quality of finishing and polishing achieved by polishing systems. Aim: To evaluate the surface texture of nanofilled composite resin (Filtek Z350XT) polished by Sof-Lex XT, Enhance and PoGo, KerrHawe and OptiDisc polishing systems. Materials and Methods: In this invitro experimental study, three polishing systems were tested for surface texture of a nanofilled composite resin (Filtek Z350XT, USA). A total of 66 specimens (2 cm in diameter and 2 cm in height) were prepared from acrylic mold. Circular cavity measuring 8 mm in diameter and 3 mm in depth were prepared in each specimen. All the cavities were filled with nanofilled composite resin. The filled specimens were divided into 3 groups of 22 each and polished by Sof-Lex XT, Enhance and PoGo, KerrHawe and OptiDisc respectively. The surface roughness was measured by surface profilometer. Data was analysed by using ANOVA test between treatment groups. Results: The surface roughness (Ra) was less for the Sof-Lex XT group (0.35±0.09) as compared to Enhance and PoGo (0.56±0.14), KerrHawe and OptiDisc groups (0.59±0.15). One-way ANOVA test revealed p≤0.05 which was statistically significant. Conclusion: The Sof-Lex XT system was found to be more effective as compared to other two systems. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the effects of different surface conditoning methods on surface texture and shear bond strength (SBS) of brackets bonded to resin nanoceramic material. Methods: Ceramic specimens were divided into two groups as metal brackets and ceramic brackets. In each group, the following five subgroups were conditoned with orthophosphoric acid (OPA), hydrofluoric acid (HFA), silica coating with Cojet, Nd: Yag laser, and Femtosecond (Fs) laser. Extra samples were used for scanning electron microscopy and 3D profilometer evaluation. Results: All surface conditioning methods caused optimum or higher SBS. Metal brackets had higher SBS than porcelain brackets, but this difference reached statistical significance only in Fs laser group. OPA caused surface modification comparable to HFA because of polymer content of resin nanoceramic. Although Fs laser and Cojet conditioning caused optimum or higher SBS, surface damage of these methods to the resin nanoceramic specimens clearly seen on 3D profilometer. Conclusion: HFA and Nd: Yag laser are effective surface conditioning methods for resin nanoceramics. OPA combined with silane application caused optimum SBS and can be used as an alternative to HFA. Surface texture changes should be considered to determine surface damage while deciding the optimum surface conditioning method for ceramics other than SBS. [ABSTRACT FROM AUTHOR]

As glazes are papery, there is no method capable of evaluating the surface wear resistance of glazed tiles. Thus, Taber abraser with rubber wheels and abrasive belts was employed to grind out a regular wear track. The volume of track was estimated using profilometer and its analyzing software precisely. The evaluation reliability of this method was verified using six float glasses, and the standard deviation of volume loss results could be controlled less than 10%. The appropriate operating parameters were investigated using float glasses and two types of ceramic tiles from different manufacturers. The method proposed in this work has potential of success to evaluate the surface wear resistance of ceramic tiles quantitatively and precisely. [ABSTRACT FROM AUTHOR]

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Automated Fiber Placement (AFP) has become a standard manufacturing technique in the creation of large scale composite structures due to its high production rates. However, the associated rapid layup that accompanies AFP manufacturing has a tendency to induce defects. We forward an inspection system that utilizes machine learning (ML) algorithms to locate and characterize defects from profilometry scans coupled with a data storage system and a user interface (UI) that allows for informed manufacturing. A Keyence LJ-7080 blue light profilometer is used for fast 2D height profiling. After scans are collected, they are process by ML algorithms, displayed to an operator through the UI, and stored in a database. The overall goal of the inspection system is to add an additional tool for AFP manufacturing. Traditional AFP inspection is done manually adding to manufacturing time and being subject to inspector errors or fatigue. For large parts, the inspection process can be cumbersome. The proposed inspection system has the capability of accelerating this process while still keeping a human inspector integrated and in control. This allows for the rapid capability of the automated inspection software and the robustness of a human checking for defects that the system either missed or misclassified. [ABSTRACT FROM AUTHOR]

This study presents an improved discrete Kalman filter for simultaneously estimating both all state variables and the unknown road roughness input for a vehicle suspension control system that plays a key role in the ride quality and handling performance while driving the vehicle. The suspension system is influenced by the road roughness input, which causes undesirable vibrations associated with vehicle instability. It is therefore important to estimate the road roughness and state variables information when designing the model-based controller for the vehicle suspension control system associated with the vehicle's vertical dynamics. However, the implementation of conventional estimation theories for the suspension control system is challenging because the road roughness acts as an unknown input and is difficult to be measured or estimated while driving. This study presents an improved Kalman filter with unknown input, which can simultaneously estimate the state variables and road roughness without any prior information about the vehicle suspension control system. The proposed road roughness input estimator is evaluated by using an in-vehicle test bed with a laser-type profilometer. Finally, the state estimation performance of the proposed estimator for a vehicle suspension control system is validated by using CarSim software. [ABSTRACT FROM AUTHOR]

This paper presents a laboratory study aiming to characterise the influences of aggregate micro-texture on the skid resistance under consideration of different wavelengths. To achieve this objective, 11 kinds of aggregates were used to prepare aggregate specimens. Micro-Deval (MD) and Aachen Polishing Machine (APM) were utilised to represent the changes in aggregate morphology which is caused by traffic loading. The Wehner/Schulze (W/S) test was used to measure the skid resistance. A high-resolution profilometer was utilised to collect the surface topography of the specimens. The two-dimensional power spectral density of the aggregate specimens was calculated based on the collected surface topography to investigate the differences in texture resulting from abrasion and polishing. Furthermore, the key wavelength ranges of the pavement surface texture responsible for the skid resistance is identified. The key wavelength range was then divided into four subranges; thereafter, the effect of the micro-texture on the skid resistance is investigated. Analyses show that the MD and APM affected different wavelength ranges of the texture. The most influential wavelength range for the skid resistance is found to be 32–128 µm. Mineral properties and the composition of aggregate directly affect the skid-resistant performance as well as the polishing resistance. [ABSTRACT FROM AUTHOR]

Surface patterning technologies represent a worldwide growing industry, creating smart surfaces and micro/nanoscale device. The advent of large-area, high-speed imprinting technologies has created an ever-growing need for rapid and non-destructive dimensional metrology techniques to keep pace with the speed of production. Here we present a new real-time optical scatterometry technique, applicable at the mesoscale when optical inspection produces multiple orders of diffraction. We validate this method by inspecting multiple silicon gratings with a variety of structural parameters. These measurements are cross-referenced with FIB, SEM and scanning stylus profilometry. Finally, we measure thermally imprinted structures as a function of imprinting temperature in order to demonstrate the method suitable for in-line quality control in nanoimprint lithography. [ABSTRACT FROM AUTHOR]

The roughness of rock discontinuities is an important input parameter for mechanical models of rock masses. To reliably calculate roughness indices, adequate representations of the surfaces are required. Various optical measuring approaches have been applied in the past. However, many studies lack information on resolution and accuracy of the resulting surface meshes. These qualities are yet important, as they explicitly affect the deduced roughness metrics. Often, the sensors do not achieve the given precision and accuracy. Moreover, no technical standards presently exist for roughness evaluation from optical measuring approaches. Therefore, previous studies are difficult to compare. To overcome these issues, this study offers a comparison of four different techniques and sensors. Here, the focus lies on laboratory use and evaluation of micro-roughness, meaning sample sizes up to 20 cm in length. Stationary structured light scanning (SLS) serves as the reference method. As results, the surface models from dense image matching are very consistent with the reference. Their calculated roughness values accord to a high degree, both for 2D and 3D indices. In addition, roughness indices deduced from models acquired with manually operated SLS show deviations from the reference yet within an acceptable range. Instead, terrestrial laser scanning turned out to be not suitable for micro-roughness evaluation, at least at laboratory scale. Furthermore, in this contribution, an algorithm is applied, which can retrace all possible profile measurements directly from the triangulated surfaces. That way the ambiguity of the profile-based roughness measure joint roughness coefficient (JRC) is made visible. [ABSTRACT FROM AUTHOR]

In this study, we propose a new surface generation model for carbon fiber reinforced thermoplastics (CFRTP) manufactured by the long fiber thermoplastic-direct (LFT-D) method. CFRTP are considered to be a next-generation structural material because of their high productivity as well as high mechanical strength and lightness. Conversely, CFRTP have a rough surface, which does not meet the automotive outer panel standard of a "class A surface." In the present study, we establish a surface roughness generation model based on a thermal shrinkage mismatch of thermoplastic resin to carbon fiber and non-uniform carbon fiber distribution. Furthermore, we construct a surface roughness estimation formula based on the model. In the calculation, a cross-sectional image of CFRTP is divided into many vertical segments. Subsequently, the thermal shrinkage of each segment is calculated with a standard deviation, an average, and a probability density of the amount of carbon fiber in each segment. The surface roughness of the manufactured CFRTP was measured using a surface profilometer. The result showed that the arithmetic surface roughness increased with the volume fraction of carbon fiber. We applied the surface roughness calculation to cross-sectional images of the specimens. Consequently, the estimated surface roughness showed the same tendency, in which the surface roughness increased with the volume fraction of carbon fiber. The slope of a regression line of the estimated surface roughness with respect to the volume fraction was 0.010, which was almost the same (0.011) as the slope of a regression line of the measured surface roughness. Furthermore, the estimation formula using a thermal shrinkage effective depth of 395 μm was able to estimate the surface roughness within a 3% average error. Using the estimation formula, it was predicted that the surface roughness increased with the standard deviation of the amount of carbon fiber in a segment. To confirm the reliability of the model and the formula, we measured the standard deviation of the amount of carbon fiber in CFRTP specimens, showing that the trend for CFRTP specimens matched the estimated values. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Toothpastes with whitening properties have emerged as an option to enable and improve the whitening of tooth structure. In recent years, toothpastes have become more specialized and can be classified as therapeutic or cosmetic. One of the most important features regarding the cosmetic function of toothpastes is the capacity to prevent or remove stains on the tooth surface, thereby whitening the teeth. OBJECTIVES: The purpose of this in vitro study was to investigate the effects of different whitening toothpastes on both human enamel and cementum surfaces. MATERIAL AND METHODS: In total, 140 of human extracted incisor teeth were split from cemento-enamel junction and embedded in gypsum blocks. Ra values were measured with a three-dimensional profilometer. Images were obtained from the samples with a scanning electron microscope. One of the seven groups created was the control group, in which the teeth were brushed with water only, and in six groups (groups 2-7), they were brushed with different whitening toothpastes. Each sample was brushed for 5 seconds for 30 days with an automatic toothbrushing machine. RESULTS: Regarding the surface roughness in cementum, no differences were detected in the control group. While all toothpastes caused a decrease in roughness, this difference was significant (p < 0.05) in group 3 and group 4. For enamel roughness, no differences were detected in the control group. The roughness decreased significantly (p < 0.05) in group 3 and group 4. In other whitening toothpaste groups, surface roughness increased but the difference was not significant (p > 0.05). CONCLUSIONS: The results of this in vitro study showed that all whitening toothpastes in this study reduced the roughness on the cementum surface. Most whitening toothpastes increased the enamel roughness, while two whitening toothpastes (Splat Special Blackwood and Colgate Optic White) reduced the enamel roughness. [ABSTRACT FROM AUTHOR]