17,595 results match your criteria surface roughness


A theoretical model of the intermittent contact of piezoelectric actuator based on Greenwood-Williamson theory.

Ultrasonics 2021 Apr 2;114:106428. Epub 2021 Apr 2.

Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Harbin 150001, China.

A theoretical model of the intermittent contact mechanism of linear piezoelectric actuator was proposed, in which the microscopic characteristics of the contact surfaces were taken into account. Greenwood-Williamson (GM) theory was involved for the first time to describe the microscopic characteristics of the contact surfaces in which the contact surfaces were considered as random rough surfaces that were composed of large amounts of asperities and the heights of the asperities conformed to a Gauss distribution. The developed theoretical model gives an insight into the influence of the microscopic properties, as well as the macroscopic and material properties on the output performance of the actuator, which may provide guidance for the design of such type of piezoelectric actuator. Read More

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Preventing Catastrophic Failure of Microfibrillar Adhesives in Compliant Systems Based on Statistical Analysis of Adhesive Strength.

ACS Appl Mater Interfaces 2021 Apr 13. Epub 2021 Apr 13.

Mechanical Engineering Department, California State University, Northridge, California 91330, United States.

Adhesives based on fibrillar surface microstructures have shown great potential for handling applications requiring strong, reversible, and switchable adhesion. Recently, the importance of the statistical distribution of adhesive strength of individual fibrils in controlling the overall performance was revealed. Strength variations physically correspond to different interfacial defect sizes, which, among other factors, are related to surface roughness. Read More

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Erosion of CAD/CAM restorative materials and human enamel: An in vitro study.

J Mech Behav Biomed Mater 2021 Apr 3;119:104503. Epub 2021 Apr 3.

Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China; Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Japan. Electronic address:

This in vitro study used the same frequency and duration of acid contact as a previous in situ/in vivo study to evaluate the effect of erosion on CAD/CAM restorative materials and human enamel and to compare the effects of in vitro and in situ/in vivo acid challenges on CAD/CAM restorative materials and human enamel. The CAD/CAM restorative materials (IPS e.max CAD, Lava Ultimate, and PMMA block) and human enamel were eroded by immersion in 150 ml of cola drink for 14 days (4 × 5 min/day). Read More

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Refractive Indexes and Spectroscopic Properties to Design Er-Doped SiO-TaO Films as Multifunctional Planar Waveguide Platforms for Optical Sensors and Amplifiers.

ACS Omega 2021 Apr 25;6(13):8784-8796. Epub 2021 Mar 25.

Laboratório de Materiais Luminescentes Micro e Nanoestruturados-Mater Lumen, Departamento de Química, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900-Campus da Usp, Ribeirão Preto-SP, 14040-900 São Paulo, Brazil.

This paper reports on the news about refractive index measurements and spectroscopic features of thin films, which can be applied as optical planar waveguides, focusing on their manufacturing processes, designs, and possible applications as optical amplifiers and sensors. Er-doped SiO-TaO planar waveguides, with Si/Ta ratios of 90:10, 80:20, 70:30, 60:40, and 50:50, were prepared by a soft sol-gel process. Multilayer films were deposited by the dip-coating technique onto 10 μm SiO-Si (100) p-type silicon and Si (100) silicon easily and successfully. Read More

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Biodegradable chitosan-poly(vinyl alcohol) intelligent films fortified with anthocyanins isolated from Clitoria ternatea and Carissa carandas for monitoring freshness of beverages.

Int J Biol Macromol 2021 Apr 8. Epub 2021 Apr 8.

Natural Product Research Center of Excellence, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112, Thailand. Electronic address:

Biodegradable chitosan-poly(vinyl alcohol) films containing natural anthocyanin-rich extracts were prepared using solvent casting method and employed as intelligent indicators for monitoring beverages freshness. The surface and cross-sectional scanning electron micrograph indicated a compact structure for the intelligent films, whereas the atomic force micrograph indicated a 16.22 and 20. Read More

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Effects of toothbrush abrasion on surface and antibacterial properties of hydroxyapatite-tryptophan complex with gray titania.

Odontology 2021 Apr 9. Epub 2021 Apr 9.

Functional Occlusal Treatment, The Nippon Dental University Graduate School of Life Dentistry At Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata-shi, Niigata, 951-8580, Japan.

Photocatalysts have attracted attention in the medical field for their antibacterial effects. However, typical photocatalysts are activated by ultraviolet rays, which may have adverse effects. Therefore, we focused on a new photocatalyst that is activated by visible light, hydroxyapatite (HAp), and amino acid complex with gray titania, and evaluated its antibacterial effects against Porphyromonas gingivalis and effect by toothbrushing. Read More

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Influence of Anionic Surfactants on the Fundamental Properties of Polymer/Reduced Graphene Oxide Nanocomposite Films.

ACS Appl Mater Interfaces 2021 Apr 9. Epub 2021 Apr 9.

Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.

Surfactants are frequently employed in the fabrication of polymer/graphene-based nanocomposites via emulsion techniques. However, the impact of surfactants on the electrical and mechanical properties of such nanocomposite films remains to be explored. We have systematically studied the impact of two anionic surfactants [sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS)] on intrinsic properties of the nanocomposite films comprising reduced graphene oxide in a matrix of poly(styrene---butyl acrylate). Read More

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[Effect of subpressure on the bonding strength of resin to polycrystalline particulates modified zirconia ceramic].

Zhonghua Kou Qiang Yi Xue Za Zhi 2021 Apr;56(4):342-348

Institute of Dental Research, Capital Medical University School of Stomatology, Beijing 100050, China.

To explore the effect of subpressure on the bonding strength of resin to polycrystalline particulates modified zirconia ceramic. One hundred and twenty pre-sintered zirconia discs were prepared and divided into the control group, the sandblasting group and the 30, 50, 70 s acid etching group (24 per group) by the random number table method. There was no additional treatment in the control group and sandblasting group before sinering. Read More

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Real-time fouling monitoring and membrane autopsy analysis in forward osmosis for wastewater reuse.

Water Res 2021 Apr 1;197:117098. Epub 2021 Apr 1.

Graduate School of Water Resources, Sungkyunkwan University (SKKU), 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, South Korea. Electronic address:

Forward osmosis process in emerging technology which can applicable in wastewater reuse and desalination simultaneously. In this study, the development of fouling on the FO membrane surface was monitored in real-time. The investigation of fouling layer physical and chemical characteristics was assessed by performance evaluation and in-depth analysis of fouling layer. Read More

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High-Quality Thin Films of UiO-66-NH2 by Coordination Modulated Layer-by-Layer Liquid Phase Epitaxy.

Chemistry 2021 Apr 8. Epub 2021 Apr 8.

Technische Universitat Munchen, Chemistry, GERMANY.

We report the fabrication of macroscopically and microscopically homogeneous, crack-free metal-organic framework (MOF) UiO-66-NH 2 (UiO: Universitet i Oslo; [Zr 6 O 4 (OH) 4 (bdc-NH 2 ) 6 ]; bdc-NH 2 2- : 2-amino-1,4-benzene dicarboxylate) thin films on silicon oxide surfaces. A DMF-free, low-temperature coordination modulated (CM), layer-by-layer liquid phase epitaxy (LPE) using the controlled secondary building block approach (CSA). Efficient substrate activation was determined as a key factor to obtain dense and smooth coatings by comparing UiO-66-NH 2 thin films grown on ozone and piranha acid-activated substrates. Read More

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Templateless, Plating-Free Fabrication of Flexible Transparent Electrodes with Embedded Silver Mesh by Electric-Field-Driven Microscale 3D Printing and Hybrid Hot Embossing.

Adv Mater 2021 Apr 7:e2007772. Epub 2021 Apr 7.

Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao, 266520, China.

Flexible transparent electrodes (FTEs) with an embedded metal mesh are considered a promising alternative to traditional indium tin oxide (ITO) due to their excellent photoelectric performance, surface roughness, and mechanical and environmental stability. However, great challenges remain for achieving simple, cost-effective, and environmentally friendly manufacturing of high-performance FTEs with embedded metal mesh. Herein, a maskless, templateless, and plating-free fabrication technique is proposed for FTEs with embedded silver mesh by combining an electric-field-driven (EFD) microscale 3D printing technique and a newly developed hybrid hot-embossing process. Read More

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Evaluation of dual-ended readout GAGG-based DOI-PET detectors with different surface treatments.

Med Phys 2021 Apr 7. Epub 2021 Apr 7.

Department of Bioengineering, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.

Purpose: Parallax error is a major issue in small animal positron emission tomography (PET) scanners which are used in preclinical studies or detailed scanning of human organs. Several methods have been proposed and investigated to reduce this radial artifact in PET images by estimating the depth of interaction (DOI) of 511-keV photons in the crystal. Among all, the dual-ended readout method seems to be very simple and effective as it does not have any fabrication and readout complications. Read More

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Bonding Behavior Between Polyetheretherketone and Polymethylmethacrylate Acrylic Denture Polymer.

J Adhes Dent 2021 Apr;23(2):145-158

Purpose: To investigate the impact of pretreatment and conditioning on shear bond strength (SBS), surface free energy (SFE) and surface roughness (SR) between polyetheretherketone (PEEK) and cold-cured polymethylmethacrylate (PMMA).

Materials And Methods: PEEK substrates (Dentokeep PEEK Disc, nt-trading) were air abraded with Al2O3 particles of different grain sizes applied with varying pressure at 1) 0.2 MPa - 50 µm Al2O3; 2) 0. Read More

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Sesame Oil () as a New Challenge for Reinforcement of Conventional Glass Ionomer Cement, Could It Be?

Authors:
Neven S Aref

Int J Dent 2021 22;2021:5516517. Epub 2021 Mar 22.

Department of Dental Biomaterials, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.

Purpose: Despite the advantages of glass ionomer cement (GIC) including chemical bonding to the tooth structure and fluoride release, its low-grade mechanical properties make it a topic for research. Accordingly, this study was conducted to assess the ability of sesame oil as a natural bioactive additive to reinforce conventional glass ionomer cement.

Materials And Methods: Sesame oil was blended into the liquid component of the cement in ratios of 3 and 5 (v/v%). Read More

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Forward osmosis membranes for high-efficiency desalination with Nano-MoS composite substrates.

Chemosphere 2021 Mar 20;278:130341. Epub 2021 Mar 20.

Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Technology, Shandong University, Jinan, 250100, China; School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address:

Attractive membranes are critical for improving efficiencies of forward osmosis (FO) desalination process. In this study, a novel FO-PES-MoS thin film composite (TFC) membrane was assembled using the phase transfer method through merging MoS nanosheets into substrate casting solution. A sequence of characterization techniques was applied to test microstructures and physicochemical properties of the membranes and modification mechanisms based on MoS concentrations. Read More

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A Novel Sulfone Derivative Containing 1,3,4-Oxadiazole Controls Tea Plant Disease through Inhibiting Lasiodiplodia theobromae Proliferation by Reducing the Ergosterol Content.

Mol Plant Microbe Interact 2021 Apr 6. Epub 2021 Apr 6.

Guizhou University, 71206, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Huaxi street, Guiyang City, Guizhou Province, Guiyang, China, 550025;

Diseases caused by fungi can affect the quality and yield of the leaves of tea plants [Camellia sinensis (L.) Kuntze]. At present, the availability of highly effective and safe fungicides for controlling tea plants remains limited. Read More

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Thirty-six-month clinical evaluation of posterior high-viscosity bulk-fill resin composite restorations in a high caries incidence population: interim results of a randomized clinical trial.

Clin Oral Investig 2021 Apr 6. Epub 2021 Apr 6.

Faculdade de Odontologia, Universidade de Pernambuco, Av. Gov. Agamenon Magalhães, s/n; Santo Amaro, Recife, Pernambuco, 50.100-010, Brazil.

Objectives: This study compared the clinical performance of two bulk-fill (BF) and one conventional resin composite in a population with a high caries incidence.

Materials And Methods: A total of 138 class I and II restorations were performed and randomly divided into three groups (n = 46) with equal allocation: Filtek BF (FBF; 3M ESPE), Tetric EvoCeram BF (TBF; Ivoclar Vivadent), and control Filtek Z250 (Z250; 3M ESPE). The evaluations were performed using the USPHS and FDI criteria at baseline and after 12 and 36 months by a previously calibrated evaluator. Read More

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Design and characteristics of a Maxwell force-driven liquid lens.

Opt Express 2021 Mar;29(6):8323-8332

Varifocal lenses (especially large-aperture lenses), which are formed by two immiscible liquids based on electrowetting and dielectrophoretic effects, are usually modulated by an external high-voltage power source, with respect to the volume of the liquid. Hence, a Maxwell force-driven liquid lens with large aperture and low threshold voltage is proposed. With the polarization effect, the accumulated negative charges on the surface of the polyvinyl chloride/dibutyl adipate gel near the anode results in the generation of Maxwell force and deformation with cosine wave. Read More

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Bespoke mirror fabrication for quantum simulation with light in open-access microcavities.

Opt Express 2021 Mar;29(7):10800-10810

In this work, we use focused ion beam (FIB) milling to generate custom mirror shapes for quantum simulation in optical microcavities. In the paraxial limit, light in multimode optical microcavities follows an equation of motion which is equivalent to Schrödinger's equation, with the surface topography of the mirrors playing the role of the potential energy landscape. FIB milling allows us to engineer a wide variety of trapping potentials for microcavity light, through exquisite control over the mirror topography, including 2D box, 1D waveguide, and Mexican hat potentials. Read More

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A digital holography ex situ measurement characterization of plasma-exposed surface erosion from an electrothermal arc source.

Rev Sci Instrum 2021 Mar;92(3):033517

Third Dimension Technologies, Oak Ridge, Tennessee 37830, USA.

Digital holography has been proposed to fulfill a need for an imaging diagnostic capable of in situ monitoring of surface erosion caused by plasma-material interaction in nuclear fusion devices. A digital holography diagnostic for 3D surface erosion measurement has been developed at Oak Ridge National Laboratory with the goal of deployment on a plasma device. A proof-of-concept in situ demonstration is planned which would involve measurement of plasma erosion on targets exposed to an electrothermal arc source. Read More

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Adaptive responses of Kluyveromyces marxianus CCT 7735 to 2-phenylethanol stress: alterations in membrane fatty-acid composition, ergosterol content, exopolysaccharide production and reduction in reactive oxygen species.

Fungal Genet Biol 2021 Apr 2:103561. Epub 2021 Apr 2.

Laboratory of Microbial Physiology, Department of Microbiology, Universidade Federal de Viçosa, Viçosa, MG, Brazil. Electronic address:

2-phenylethanol (2-PE) is a higher aromatic alcohol with a rose-like aroma used in the cosmetic and food industries as a flavoring and displays potential for application as an antifungal. Biotechnological production of 2-PE from yeast is an interesting alternative due to the non-use of toxic compounds and the generation of few by-products. Kluyveromyces marxianus CCT 7735 is a thermotolerant strain capable of producing high 2-PE titers from L-Phe; however, like other yeast species, its growth has been strongly inhibited by this alcohol. Read More

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Surface roughness, plaque accumulation, and cytotoxicity of provisional restorative materials fabricated by different methods.

PLoS One 2021 5;16(4):e0249551. Epub 2021 Apr 5.

Department of Prosthodontics, Biomaterials Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Fars, Iran.

Fabricating method may affect the surface properties and biological characteristics of provisional restorations. This study aimed to evaluate the surface roughness, plaque accumulation, and cytotoxicity of provisional restorative materials fabricated by the conventional, digital subtractive and additive methods. Sixty-six bar-shaped specimens (2×4×10 mm) were fabricated by using provisional restorative materials through the conventional, digital subtractive and additive methods (n = 22 per group). Read More

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Investigations on the impact of the introduction of the Aloe vera into the hydrogel matrix on cytotoxic and hydrophilic properties of these systems considered as potential wound dressings.

Mater Sci Eng C Mater Biol Appl 2021 Apr 19;123:111977. Epub 2021 Feb 19.

Cracow University of Technology, Faculty of Materials Engineering and Physics, Institute of Materials Science, 37 Jana Pawła II Av., 31-864 Krakow, Poland. Electronic address:

In the paper, synthesis of chitosan-based hydrogels modified with Aloe vera juice is presented. The novelty of the research was a combination of hydrogel materials with properties beneficial in viewpoint of their use as modern wound dressings and Aloe vera juice supporting the wound healing process. Hydrogels have been obtained via UV radiation. Read More

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Sub-nano to nanometer wear and tribocorrosion of titanium oxide-metal surfaces by in situ atomic force microscopy.

Acta Biomater 2021 Mar 31. Epub 2021 Mar 31.

Clemson - MUSC Bioengineering Program, Department of Bioengineering, Clemson University and the Medical University of South Carolina, 68 Presidents Street, Charleston, SC 20425, United States. Electronic address:

Wear and tribocorrosion of passive oxide film covered metals have been studied at the micro and macroscopic scales. Recent advances in nanotechnology have contributed to breakthroughs in understanding of fundamental friction and wear mechanisms of atomically thin 2D materials at the nanoscale. However, for metals and materials without ultra-flat surfaces, a gap in knowledge exists at or below a few nanometers, which is too small for continuum mechanics theories and experiments including conventional atomic force microscopy (AFM) methods, due to resolution limits arising from surface roughness. Read More

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Sodium alginate blended membrane with polyurethane: Desalination performance and antimicrobial activity evaluation.

Int J Biol Macromol 2021 Mar 31;182:72-81. Epub 2021 Mar 31.

Department of Chemistry, The University of Lahore, Lahore 53700, Pakistan. Electronic address:

A series of polymeric membranes were synthesized by blending polyurethane with sodium alginate (0.2, 0.4, 0. Read More

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Transport of coupled particles in rough ratchet driven by Lévy noise.

Chaos 2021 Mar;31(3):033104

School of Mathematics and Information Science, Shaanxi Normal University, Xi'an 710119, People's Republic of China.

This paper studies the transport of coupled particles in a tilted rough ratchet potential. The relationship between particles transport and roughness, noise intensity, external force, coupling strength, and free length is explored numerically by calculating the average velocity of coupled particles. Related investigations have found that rough potential can accelerate the process of crossing the barrier by increasing the particles velocity compared with smooth potential. Read More

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Tool Wear and Surface Evaluation in Drilling Fly Ash Geopolymer Using HSS, HSS-Co, and HSS-TiN Cutting Tools.

Materials (Basel) 2021 Mar 26;14(7). Epub 2021 Mar 26.

Faculty of Chemical Engineering, Universiti Teknologi MARA, Cawangan Pulau Pinang, 13500 Permatang Pauh, Malaysia.

This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. Read More

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Cutting Forces and Tool Wear Investigation during Turning of Sintered Nickel-Cobalt Alloy with CBN Tools.

Materials (Basel) 2021 Mar 26;14(7). Epub 2021 Mar 26.

Chair of Production Engineering, Faculty of Mechanical Engineering, Cracow University of Technology, Al. Jana Pawła II 37, 31-864 Kraków, Poland.

This article describes issues related to the machining of parts made of sintered nickel-cobalt alloy. Longitudinal turning with a CBN (cubic boron nitride) tool was analyzed. The results of experiments showed the influence of cutting parameters in the field of finishing machining on the values of cutting forces and specific cutting force, taking into account the wear of the cutting edge. Read More

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Quantification of Carbonic Contamination of Fused Silica Surfaces at Different Stages of Classical Optics Manufacturing.

Materials (Basel) 2021 Mar 26;14(7). Epub 2021 Mar 26.

Faculty of Engineering and Health, HAWK University of Applied Sciences and Arts, Von-Ossietzky-Str. 99/100, 37085 Göttingen, Germany.

The chemical composition of ground and polished fused silica glass surfaces plays a decisive role in different applications of optics. In particular, a high level of carbon impurities is often undesirable for further processing and especially for gluing or cementing where adhesion failure may be attributed to carbonic surface-adherent contaminants. In this study, the surface carbon content at different stages of classical optics manufacturing was thus investigated. Read More

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The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates.

Materials (Basel) 2021 Mar 22;14(6). Epub 2021 Mar 22.

Faculty of Materials, Metallurgy and Recycling, Technical University of Košice, Letná 9, 042 00 Košice, Slovakia.

The presented research background is a car body manufacturer's request to test the car body's components welded from dissimilar steel sheets. In view of the vehicle crew's protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Read More

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