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81.
Ultra-high molecular weight polyethylene (UHMWPE)/ graphene nanoplatelets (GNPs) nanocomposite coatings were developed to reduce friction and wear in the absence of liquid lubrication. UHMWPE nanocomposite powders with different loadings (0.25, 1, and 2 wt.%) of GNPs were prepared and electrostatic spraying technique was then used to deposit the nanocomposite powders on aluminum alloy to form a thin coating. Friction and wear tests were conducted on the coatings against a flat-end pin, made of hardened tool steel to determine the best loading of GNPs. That was further tested to investigate the effect of sliding speed and contact pressure on its tribological properties and to establish coating operating limits. Results showed that UHMWPE nanocomposite coating reinforced with 1 wt.% GNPs showed the best tribological performance. It reduced wear rate by about 51% as compared to the pristine UHMWPE coating. The coating sustained a maximum sliding speed of 1 m/s at a contact pressure of 4 MPa equivalent to a pressure and velocity (PV) value of 4 MPa.m/s. 相似文献
82.
Characterization and mechanical properties of exfoliated graphite nanoplatelets reinforced polyethylene terephthalate/polypropylene composites 下载免费PDF全文
I. M. Inuwa Azman Hassan S. A. Samsudin M. K. Mohamad Haafiz M. Jawaid K. Majeed N. C. Abdul Razak 《应用聚合物科学杂志》2014,131(15)
Recently, graphene and its derivatives have been used to develop polymer composites with improved or multifunctional properties. Exfoliated graphite nanoplatelets (GNP) reinforced composite materials based on blend of polyethylene terephthalate (PET), and polypropylene (PP) compatibilized with styrene–ethylene–butylene–styrene‐g‐maleic anhydride is prepared by melt extrusion followed by injection molding. Characterization of the composites' microstructure and morphology was conducted using field emission scanning electron microscopy, transmission electron microscopy (TEM), X‐ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). Tensile and impact strengths of test specimens were evaluated and the results showed maximum values at 3phr GNP in both the cases. Morphological studies showed that the GNPs were uniformly dispersed within the matrix. Results from XRD analysis showed uniformly dispersed GNPs, which may not have been substantially exfoliated. FTIR spectroscopy did not show any significant change in the peak positions to suggest definitive chemical interaction between GNP and the matrix. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40582. 相似文献
83.
Rare earth-doped ZnO hierarchical micro/nanospheres were prepared by a facile chemical precipitation method and characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The results showed that the as-synthesized products were well-crystalline and accumulated by large amount of interleaving nanosheets. It was also observed that the rare earth doping increased the visible light absorption ability of the catalysts and red shift for rare earth-doped ZnO products appeared when compared to pure ZnO. The photocatalytic studies revealed that all the rare earth-doped ZnO products exhibited excellent photocatalytic degradation of phenol compared with the pure ZnO and commercial TiO2 under visible light irradiation. Nd-doped ZnO had the highest photocatalytic activity among all of the rare earth-doped ZnO products studied. The optimal Nd content was 2.0 at% under visible light irradiation. The enhanced photocatalytic performance of rare earth-doped ZnO products can be attributed to the increase in the rate of separation of photogenerated electron–hole pairs and hydroxyl radicals generation ability as evidenced by photoluminescence spectra. 相似文献
84.
Mohammadreza Mahmoudi Sungjin Kim Arif M. Arifuzzaman Tomonori Saito Corson L. Cramer Majid Minary-Jolandan 《International Journal of Applied Ceramic Technology》2022,19(2):939-948
Preceramic polymer resins are attractive for the 3D printing of net-shaped ceramic components. Recently various processes have been demonstrated for 3D printing of polymer-derived ceramics (PDCs). Ultimately in these processes, the process outcomes strongly depend on the process parameters. In particular, for PDCs the ceramic density, and ceramic yield are affected by the catalyst concentration and cross-linking duration. Here, we use thermal analysis and FTIR to quantify the interrelation of the process parameters on the process outcome for polysilazanes and demonstrate 3D printing of PDC components based on the best-identified process parameters. The results of this work can be used as guidelines for future additive manufacturing of PDCs. 相似文献
85.
Velayati Mahin Sabouri Zahra Masoudi Abdolhossein Mostafapour Asma Khatami Mehrdad Darroudi Majid 《SILICON》2022,14(13):7541-7554
Silicon - In this research, epoxy polyurethane-nano silica nanocomposites have been synthesized using an in-situ method, for which SiO2 nanocomposites had been initially ready in N,... 相似文献
86.
Dr. Yun Wang Dr. Shougang Hu Abdul M. Gabisi Jr. Joyce A. V. Er Arthur Pope Gayle Burstein Christopher L. Schardon Dr. Arturo J. Cardounel Dr. Suhendan Ekmekcioglu Dr. Walter Fast 《ChemMedChem》2014,9(4):792-797
Inhibitors of the human enzyme dimethylarginine dimethylaminohydrolase‐1 (DDAH‐1) can raise endogenous levels of asymmetric dimethylarginine (ADMA) and lead to a subsequent inhibition of nitric oxide synthesis. In this study, N5‐(1‐imino‐2‐chloroethyl)‐L ‐ornithine (Cl‐NIO) is shown to be a potent time‐ and concentration‐dependent inhibitor of purified human DDAH‐1 (KI=1.3±0.6 μM ; kinact=0.34±0.07 min?1), with >500‐fold selectivity against two arginine‐handling enzymes in the same pathway. An activity probe is used to measure the “in cell” IC50 value (6.6±0.2 μM ) for Cl‐NIO inhibition of DDAH‐1 artificially expressed within cultured HEK293T cells. A screen of diverse melanoma cell lines reveals that a striking 50/64 (78 %) of melanoma lines tested showed increased levels of DDAH‐1 relative to normal melanocyte control lines. Treatment of the melanoma A375 cell line with Cl‐NIO shows a subsequent decrease in cellular nitric oxide production. Cl‐NIO is a promising tool for the study of methylarginine‐mediated nitric oxide control and a potential therapeutic lead compound for other indications with elevated nitric oxide production, such as septic shock and idiopathic pulmonary fibrosis. 相似文献
87.
In this study, we devised a new concept for the precise nanofabrication of Au-Si fibrous nanostructures using megahertz femtosecond laser irradiation in air and atmospheric pressure conditions. The weblike fibrous nanostructures of Au thin layer on silicon substrate, which are proposed for the application of solar cells, exhibit a specific improvement of the optical properties in visible wavelength. Varying numbers of laser interaction pulses were used to control the synthesis of the nanofibrous structures. Electron microscopy analysis revealed that the nanostructures are formed due to the aggregation of polycrystalline nanoparticles of the respective constituent materials with diameters varying between 30 and 90 nm. Measurement of the reflectance through a spectroradiometer showed that the coupling of incident electromagnetic irradiation was greatly improved over the broadband wavelength range. Lower reflectance intensity was obtained with a higher number of laser pulses due to the bulk of gold nanoparticles being agglomerated by the mechanism of fusion. This forms interweaving fibrous nanostructures which reveal a certain degree of assembly.
PACS
81.05.Zx; 81.07.-b 相似文献88.
In this research, the effect of carbon dioxide laser irradiation on various properties of raw and bleached cotton fabrics, including fabric weight, bending rigidity, wetting, and air permeability, as well as dyeing, was examined and compared. The experiments were carried out at three different laser powers ranging from 4.5 to 6 W to determine the effect of laser treatment on fabric properties. In particular, the influence of laser irradiation on the dyeing properties of treated fabrics with CI Reactive Blue 198 was studied. The colour change of laser‐treated fabrics was determined by calculation of the K/S values as a function of fabric reflectance. The morphological changes in laser‐treated fabrics were observed by scanning electron microscopy. The effects of laser treatment on the properties of raw and bleached cotton fabrics were varied. For instance, the wettability of raw cotton samples was reduced after laser irradiation, whereas the wettability of bleached cotton fabrics was greater. Possible reasons for the various dyeing behaviours observed with irradiation at different laser powers are discussed. 相似文献
89.
Formulation of a cost‐effective, high‐performance and eco‐friendly lubricant, largely depends on the base oil quality, then the selection of suitable additives and their proportions. Vegetable oils, identified to be eco‐friendly, renewable, future‐available and cost‐effective treasures for lubricant formulation, apart from processing, will rely much on suitable additives to meet the performance requirements for automotive shock absorber (ASA) fluids. Additives that will guarantee performance, longevity and eco‐friendliness of formulated vegetable‐based functional fluids have to be uncommonly effective, resistant to depletion, non‐toxic and highly biodegradable. Their selection in these regards will require skills and experience, which will harness the various arms of synergism as effective tools to succour the known weaknesses of the base oil. This is a review on additives that could be used in formulation of vegetable oil‐based (ASA) fluids. The outcome shows that there are customary and novel additives that are suitable for formulating vegetable oil‐based ASA fluids. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
90.
Zuhaib Siddiqui Nigel. J Horan Abdul R Sahito Jamila Abdulkadir Sheeraz A Memon 《Water and Environment Journal》2014,28(4):483-489
Energy production from a coblended mixture of biosolids and food waste was optimised for hydrogen and methane production. Four different blends were prepared by varying the carbohydrate : protein (carb : pro) ratios. The biosolids contained a low carbohydrate fraction and so was not suitable for hydrogen production when used alone. However coblending this waste with a carbohydrate‐enriched food waste produced a greater hydrogen yield, making this option viable. Batch studies showed that the optimised mix had a biosolids concentration of 25.7% (w/w). The largest hydrogen yield of 198.5 mL/gVSremoved was observed when the carb : pro was 2.78, and this was threefold higher than the other carb : pro ratios evaluated in this study. The digestate recovered after hydrogen recovery had a C : N of 17.5, which is in the ideal range for methane production. The biochemical methane potential test showed a methane yield of 239 mL/gVSremoved, and the total volatile solids destruction following two‐phase hydrogen and methane production was 93%. 相似文献