scholarly journals Deformation due to sliding of single and woven carbon tows in dry and epoxy-lubricated conditions

2021 ◽  
Author(s):  
Olga Smerdova ◽  
Omar Benchekroun ◽  
Noel Brunetière
Keyword(s):  
Carbon Fiber ◽  
Experimental Work ◽  
Glass Plate ◽  
Optical Microscope ◽  
Deformation Mechanisms ◽  
Transparent Glass ◽  
Sliding Direction ◽  
Residual Displacements ◽  
Before And After ◽  
Flat Tool

This experimental work focuses on the evaluation of deformation mechanisms due to sliding between carbon fiber tows with a flat tool in dry and lubricated with liquid resin conditions. The experiments were carried out on manually woven and single tows. The effect of angle between tow axes and sliding direction was also studied. The topography of the tows in contact with a sliding transparent glass plate was measured with a 3D optical microscope before and after sliding. These measurements revealed a decrease of roughness with sliding in all tested conditions, a contraction of lubricated single tows in perpendicular to sliding orientation, and high residual displacements in lubricated woven tows in 0°/90° orientation and dry single tows in perpendicular to sliding orientation.

EVALUATION OF TRIBOTECHNICAL PROPERTIES OF THE COATING OBTAINED BY ELECTRIC SPARK HARDENING

2020 ◽  
Vol 4 (141) ◽  
pp. 157-163
Author(s):  
IL’YA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Wear Resistance ◽  
Reference Sample ◽  
Optical Microscope ◽  
Research Purpose ◽  
Tribotechnical Properties ◽  
Uncoated Surface ◽  
Before And After ◽  
Materials Used ◽  
Friction Track

When applying coatings using various methods on the surfaces of moving parts that work in joints, it is important to make sure that the coatings are strong and wear-resistant in order to return them to their original resource. All existing hardening technologies and materials used to perform coatings have their own characteristics, therefore, the quality of the resulting coatings can be judged only after specific tests. (Research purpose) The research purpose is in evaluating the properties of the coating obtained by the method of electric spark hardening, and its ability to resist friction and mechanical wear. (Materials and methods) Authors conducted tests on the basis of the "Nano-Center" center for collective use. A coating was applied on the BIG-4M unit with a VK-8 hard alloy electrode, tribological properties were evaluated on a CSM Instruments TRB-S-DE-0000 tribometer, the width of the friction track was measured after the test using an inverted OLYMPUS gx51 optical microscope, and samples were weighed before and after the test on a VLR-200 analytical balance. Conducted research in accordance with GOST 23.224-86 and RD 50-662-88 guidelines. (Results and discussion) The article presents performed tests on the run-in and wear resistance of the coating. The samples were worked on with a step-by-step increase in the load. During the tests, the friction force was drawed on the diagram. Authors compared the results with the reference sample, an uncoated surface. (Conclusions) The resulting coating has better run-in and wear resistance compared to the standard, and the increase in wear resistance in dry friction conditions is very significant.

scholarly journals Recent advances in characterizing the “bee” structures and asphaltene particles in asphalt binders

2020 ◽  
Vol 13 (6) ◽  
pp. 697-706
Author(s):  
Yuhong Wang ◽  
Kecheng Zhao ◽  
Fangjin Li ◽  
Qi Gao ◽  
King Wai Chiu Lai
Keyword(s):  
Near Field ◽  
Asphalt Binder ◽  
Optical Microscope ◽  
Asphalt Binders ◽  
Zero Shear Viscosity ◽  
Surface Features ◽  
Asphaltene Content ◽  
Scanning Transmission ◽  
Before And After ◽  
Binder Aging

AbstractThe microscopic surface features of asphalt binders are extensively reported in existing literature, but relatively fewer studies are performed on the morphology of asphaltene microstructures and cross-examination between the surface features and asphaltenes. This paper reports the findings of investigating six types of asphalt binders at the nanoscale, assisted with atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). The surface features of the asphalt binders were examined by using AFM before and after being repetitively peeled by a tape. Variations in infrared (IR) absorbance at the wavenumber around 1700 cm−1, which corresponds to ketones, were examined by using an infrared s-SNOM instrument (scattering-type scanning near-field optical microscope). Thin films of asphalt binders were examined by using STEM, and separate asphaltene particles were cross-examined by using both STEM and AFM. In addition, connections between the microstructures and binder’s physicochemical properties were evaluated. The use of both microscopy techniques provide comprehensive and complementary information on the microscopic nature of asphalt binders. It was found that the dynamic viscosities of asphalt binders are predominantly determined by the zero shear viscosity of the corresponding maltenes and asphaltene content. Limited samples also suggest that the unique bee structures are likely related to the growth of asphaltene content during asphalt binder aging process, but more asphalt binders from different crude sources are needed to verify this finding.

scholarly journals Effect of natural disinfectant (Moringa oleifera) and a chemical disinfectant (calcium hypochlorite) on nematode eggs: bioefficiency and impact of physico-chemical variables

2020 ◽  
Vol 10 (2) ◽  
pp. 335-346
Author(s):  
Arnold Landry Fotseu Kouam ◽  
Gideon Aghaindum Ajeagah
Keyword(s):  
Petri Dish ◽  
Nematode Species ◽  
Optical Microscope ◽  
Chemical Parameters ◽  
Calcium Hypochlorite ◽  
Physico Chemical ◽  
Before And After ◽  
Nematode Eggs ◽  
Chemical Disinfectant ◽  
Physical And Chemical

Abstract The aim of this study is to determine the effectiveness of disinfectant on the viability of eggs from three nematode species (Ascaris, Trichuris, Ankylostoma). It was conducted in a microcosm from June 2018 to June 2019. The wastewater scan was sampled using 5 L sterile containers, the sample was arranged in four replicas, three tests and one control. The test samples received three disinfectants (Moringa, calcium hypochlorite and Moringa associated with calcium hypochlorite) at varying concentrations. The physical and chemical parameters were measured before and after the application of each disinfectant. The samples were then observed under an optical microscope. The viability of the eggs was determined by incubating the Petri dish samples at 30 °C for 30 days. The analyses show that some physicochemical parameters can significantly influence the efficacy of disinfectant on the eggs. The calcium hypochlorite associated with Moringa at 0.6 g/L showed greater efficacy on reducing viability and inactivation of eggs with 100% efficacy yield rates on Ankylostoma and Trichuris trichiuria and 97% on Ascaris lumbricoides eggs; this efficacy is significantly different from that observed on samples treated with Moringa and simple calcium hypochlorite. Of the three parasites tested, A. lumbricoides showed greater resistance to the disinfectant.

Fabrication and characterization of composite MoS2-TiO2 coating material

2021 ◽  
pp. 095440622110157
Author(s):  
Avinash V Borgaonkar ◽  
Ismail Syed ◽  
Shirish H Sonawane
Keyword(s):  
Bond Strength ◽  
Treatment Method ◽  
Optical Microscope ◽  
Scratch Resistance ◽  
Substrate Material ◽  
Coating Film ◽  
Tribological Behaviour ◽  
Molybdenum Disulphide ◽  
Before And After ◽  
Pre Treatment

Molybdenum disulphide (MoS2) is a popularly used solid lubricant in various applications due to its superior tribological behaviour. However, it possesses poor wear resistance which requires further improvement. In the present study efforts have been made to enhance the tribological properties of pure MoS2 coating film by doping TiO2 nanoparticles as a reinforcement material. The Manganese phosphating is selected as a pre-treatment method to improve the bond strength between coating and substrate. The coating is bonded with the substrate material employing sodium silicate as a binder. The effects of wt. % of TiO2 onto the mechanical properties of composite MoS2-TiO2 coating such as hardness and bond strength have been studied. In addition coating microstructure before and after experimental test was studied using optical microscope and scanning electron microscope. It was also found that with increase in wt. % addition of TiO2 upto 15% into MoS2 base matrix, the hardness of coating increases proportionally. Beyond 15 wt. % addition of TiO2, the coating becomes brittle in nature. This leads to reduction in the scratch resistance.

Effects of Cr+ ion implantation on the oxidation of Ni3Al

1993 ◽  
Vol 8 (4) ◽  
pp. 734-740 ◽  
Author(s):  
M. Chen ◽  
S. Patu ◽  
J.N. Shen ◽  
C.X. Shi
Keyword(s):  
Oxidation Resistance ◽  
Layer Structure ◽  
Surface Region ◽  
Optical Microscope ◽  
Al Alloy ◽  
Temperature Oxidation ◽  
Intermediate Layers ◽  
Air Interface ◽  
Before And After ◽  
High Temperature Oxidation Behavior

Ni3Al samples were implanted with different doses of 150 keV Cr+ ions to modify the surface region. The high temperature oxidation behavior was tested. The surface layer structure was investigated by AES, TEM, XRD, and optical microscope before and after the test. The experimental results show that chromium ions turn a small amount of ordered superlattice Ni3Al phase into a disordered Ni–Al–Cr phase. Also there is a bcc chromium phase in the implanted sample. Implanted Ni3Al alloy has better oxidation resistance than the unimplanted one at 900 °C. The oxide layer is of a multilayer structure after 50 h oxidation, composed of a NiO inner layer, Cr2O3, spinel NiAl2O4 intermediate layers, and an α–Al2O3 external layer at the oxide/air interface. The α-Al2O3 and Cr2O3 are independent scale-like layers. The two protective layers improve the oxidation resistance significantly. The effects of implanted elements and possible reaction mechanisms are discussed.

scholarly journals Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes

2021 ◽  
Vol 3 ◽  
Author(s):  
Elena della Valle ◽  
Beomseo Koo ◽  
Paras R. Patel ◽  
Quentin Whitsitt ◽  
Erin K. Purcell ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Cross Sections ◽  
Minimal Scarring ◽  
Pulse Testing ◽  
Implant Tests ◽  
Before And After ◽  
Voltage Transients ◽  
Scanning Electron

Ultrasmall microelectrode arrays have the potential to improve the spatial resolution of microstimulation. Carbon fiber (CF) microelectrodes with cross-sections of less than 8 μm have been demonstrated to penetrate cortical tissue and evoke minimal scarring in chronic implant tests. In this study, we investigate the stability and performance of neural stimulation electrodes comprised of electrodeposited platinum-iridium (PtIr) on carbon fibers. We conducted pulse testing and characterized charge injection in vitro and recorded voltage transients in vitro and in vivo. Standard electrochemical measurements (impedance spectroscopy and cyclic voltammetry) and visual inspection (scanning electron microscopy) were used to assess changes due to pulsing. Similar to other studies, the application of pulses caused a decrease in impedance and a reduction in voltage transients, but analysis of the impedance data suggests that these changes are due to surface modification and not permanent changes to the electrode. Comparison of scanning electron microscope images before and after pulse testing confirmed electrode stability.

scholarly journals Corrosion Characteristics of Copper in Malaysian Bioethanol and Gasoline Blends

2013 ◽  
Vol 467 ◽  
pp. 122-126 ◽  
Author(s):  
T. Saravana Kannan ◽  
C. Piraiarasi ◽  
Abu Saleh Ahmed ◽  
Ani Farid Nasir
Keyword(s):  
Chemical Properties ◽  
Optical Microscope ◽  
Acid Number ◽  
Morphological Properties ◽  
Engine Fuel ◽  
High Concentration ◽  
Total Acid ◽  
Hardness Tester ◽  
Fuel Blends ◽  
Before And After

The present study aims to investigate the corrosion characteristics of copper commonly encountered in the spark ignition (SI) engine fuel system with Malaysian bioethanol and gasoline blends. Static immersion tests in E0 (gasoline), E10 and E85 were carried out at room temperature for 1320 h. Mechanical, physical and chemical properties of copper was investigated before and after immersion tests. Investigations were carried out on change in morphological properties using optical microscope; change in chemical structure using FTIR; change in mass and volume by weight loss measurement; hardness changes using universal hardness tester; and change of chemical properties of the fuel blends using total acid number titration method. The test results showed that corrosion of copper was increased with the high concentration of ethanol in the blends.

Tensile Properties and Fracture Behavior of SiCp/AC4CH Composite at Loading Velocities of up to 10m/s

2004 ◽  
Vol 449-452 ◽  
pp. 305-308
Author(s):  
Lei Wang ◽  
Toshiro Kobayashi ◽  
Chun Ming Liu
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Tensile Deformation ◽  
Optical Microscope ◽  
Fracture Elongation ◽  
Before And After

Tensile test at loading velocities up to 10 m·s-1(strain rate up to 3.2x102s-1) was carried out forr SiCp/AC4CH composite and AC4CH alloy. The microstructure of the composite before and after tensile deformation was carefully examined with both optical microscope and SEM. The experimental results demonstrated that the ultimate tensile strength (UTS) and yield strength (YS) increase with increasing loading velocity up to 10 m·s-1. Comparing with AC4CH alloy, the fracture elongation of the composite is sensitivity with the increasing strain rate. The YS of both the composite and AC4CH alloy shows more sensitive than that of the UTS with the increasing strain rate, especially in the range of strain rate higher than 102s-1.

Experimental and Analytical Resin Impregnation Characterization in Carbon Fiber Reinforced Thermoplastic Composites

2020 ◽  
Author(s):  
Satoshi Kobayashi ◽  
Toshiko Osada
Keyword(s):  
Carbon Fiber ◽  
Optical Microscope ◽  
Textile Composites ◽  
Continuity Condition ◽  
Thermoplastic Composites ◽  
Molding Pressure ◽  
Cross Sectional ◽  
Molding Temperature ◽  
Resin Impregnation ◽  
Molding Condition

Abstract Effect of molding condition on resin impregnation behavior and the associated mechanical properties were investigated for carbon fabric reinforced thermoplastic composites. Carbon fiber yarn (TORAYCA, Toray) was used as a reinforcement, and thermoplastic PI (AURUM PL 450 C, Mitsui Chemicals) was used as the matrix. CFRTP textile composites were compression-molded with a hot press system under the molding temperature, 390 °C, 410 °C and 430 °C, molding pressure 2 MPa and 4 MPa and molding time 0∼300 s. In order to evaluate the impregnated state, cross sectional observation was performed with an optical microscope. Specimen cross-section was polished and finished with alumina slurry for a clear observation. The images observed were processed through image processing software to obtained impregnation ratio which defined as the resin impregnation area to the cross-sectional area of a fiber yarn. Resin impregnation was accelerated with molding temperature and pressure. At molding temperature more than 410 °C, resin impregnation was similar irrespective of temperature. Tensile test results indicated that modulus and strength increased with resin impregnation. Resin impregnation during molding was predicted using the analytical model based on Darcy’s law and continuity condition. The analysis could successfully predict the impregnation behavior despite the difference in molding pressure and temperature.

scholarly journals Fabrication of Structural-Coloured Carbon Fabrics by Thermal Assisted Gravity Sedimentation Method

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1133
Author(s):  
Jiali Yu ◽  
Cheng Hao Lee ◽  
Chi-Wai Kan ◽  
Shixin Jin
Keyword(s):  
Traffic Safety ◽  
Self Assembly ◽  
Optical Microscope ◽  
Chemical Information ◽  
Sedimentation Method ◽  
Emulsion Polymerisation ◽  
Before And After ◽  
Crystal Films ◽  
Gravity Sedimentation ◽  
Carbon Fabrics

Structural-coloured poly(styrene-methyl methacrylate-acrylic acid) (Poly(St-MMA-AA)) deposited carbon fabrics (Poly(St-MMA-AA)/PCFs) with fascinating colours (salmon, chartreuse, springgreen, skyblue, mediumpurple) changing with the (Poly(St-MMA-AA) nanoparticle sizes can be facilely fabricated by the thermal-assisted gravity sedimentation method that facilitates the self-assembly of Poly(St-MMA-AA) colloidal nanoparticles to generate photonic crystals. The particle sizes of Poly(St-MMA-AA) copolymer with core/shell structure varying from 308.3 nm to 213.1 nm were controlled by adjusting the amount of emulsifier during emulsion polymerisation. The presence of the intrinsic chemical information of Poly(St-MMA-AA) copolymer has been ascertained by Raman and Fourier Transform Infrared (FT-IR) Spectroscopy analysis. Colour variation of the as-prepared structural-coloured carbon fabrics (Poly(St-MMA-AA)/PCFs) before and after dipping treatment were captured while using an optical microscope. The structural colours of Poly(St-MMA-AA)/PCFs were assessed by calculating the diffraction bandgap according to Bragg’s and Snell’s laws. The Poly(St-MMA-AA) photonic crystal films altered the electrical properties of carbon fabrics with the resistivity growing by five orders of magnitude. The differential electrical resistivity between Poly(St-MMA-AA)/PCFs and wet Poly(St-MMA-AA)/PCFs combined with the corresponding tunable colours can be potentially applied in several promising areas, such as smart displays, especially signal warning displays for traffic safety.

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