This study aims to examine the morphology and mechanical properties (tensile, flexural, and compressive) of epoxy composites reinforced with epoxy date palm leaves (EDPL), epoxy date palm branch (EDPB), and epoxy/hardener date palm core shell (EDPC) fibers (particle size <1 μm depend on the date palm fibers). A three-step technique was used to obtain the composites. The EDPL composites showed a maximum tensile strength of 3.45 MPa, while the EDPB composites showed maximum compressive and flexural rigidity of 9.46 and 5.55 MPa, respectively, owing to the good compatibility of fiber-matrix bonding. In this work, epoxy composites reinforced with date palm fibers (DPF) leaves, branches, and core shell were recycled using a cost-effective and easily reproducible three-step technique. EDPC fibers fabricated with 64.65% weight carbon fibers content demonstrated improved tensile strengths and stiffness properties. The three samples of palm date composites revealed mechanical properties that could be used to trial these fibers for manufacturing purposes, and to exploit their extraordinary mechanical properties shown in current results. 相似文献
Hematite/maghemite nano-particles were synthesized by combustion method using different ratios of fuel. Effects of these ratios on crystalline phases, crystallite size, morphological and magnetic properties of the nano-particles have been investigated. The products were characterized by XRD, SEM and EDX techniques. Magnetic properties of the as prepared nano-particles were evaluated on a vibrating sample magnetometer. X-ray diffraction analysis indicates that low content of fuel promotes the formation of alpha ferric oxide, whereas high content of this fuel produces gamma ferric oxide with alpha ferric oxide. Varied morphology for the glycine-treated samples compared to untreated specimen was observed. The treatment with glycine brought about an increase in the concentration of ferric species at the as prepared solids as shown from EDX analysis. However, the mixture containing hematite/maghemite nano-particles led to better magnetic properties depending upon the presence of maghemite crystallites. 相似文献
This article explores the influence of thermal radiation on the flow and heat transfer of single-walled carbon nanotubes over both a convergent and divergent channel. Flow is induced due to a Darcy–Forchheimer medium. Further, the heat transfer mechanism is analyzed in the presence of a thermal radiation process. Guided by some appropriate similarity transformations, the fundamental PDEs are converted into a self-similar system of coupled non-linear ODEs. The findings are obtained with the help of the Runge–Kutta-45-based shooting method. The roles of the Reynolds number, porosity parameter, inertia coefficient parameter, Prandtl number and radiation parameter are presented graphically. Results are displayed and show that the rate of heat transfer is higher in a divergent channel as compared to a convergent channel.
This work was undertaken to synthesize graft copolymers that possess functional groups via the radiation-induced grafting of acrylamide onto a high-density polyethylene (HDPE) substrate. The optimum conditions suitable for radiation graft copolymerization were determined. In this regard, the effects of the solvent, the inhibitor concentration, the monomer concentration and the irradiation dose on the grafting yield were investigated. Selected properties of the prepared graft copolymers were investigated to elucidate the possibility of their practical use in the removal of metals and phosphate anions. The effects of different parameters that may affect the metal chelation process, such as pH, metal feed concentration and time of contact, were also studied. A chemically modified membrane loaded with Cu(II) was used for the removal of phosphate ions from aqueous solutions. 相似文献
This study aims to examine the mechanical properties of acrylonitrile butadiene styrene specimens using ASTM 638, 695, and 790. UVC radiation was also used as a sterilizing method. The fused deposition modeling of 3D-printed polymerize with 30% filling was used to manufacture 30 specimens for tensile, compression, and bending. Half of the specimens were treated with UVC, whereas the other half were not. The chosen dosage of 13.5 J/cm2 with an exposure time of 48 min corresponds to 3650 sterilization treatments or 10 years of sterilization. The average ultimate stress in the tensile test, compression test, and bending test was 34.5 ± 7.4, 25.4 ± 0.5, and 24.5 ± 2.1 Mpa, respectively. The analysis of variance test shows that UVC radiation has a demonstrable influence on tensile specimens, with a P-value of 0.012, which is less than the significance threshold of 0.05. Thus, the null hypothesis is rejected.
Silver nanoparticle (NP) paste was fabricated and used to bond copper wire to copper foil at low temperatures down to 160°C.
The silver NP paste was developed by increasing the concentration of 50 nm silver NP sol from 0.001 vol.% to 0.1 vol.% by
centrifugation. The 0.001 vol.% silver NP sol was fabricated in water by reducing silver nitrate (AgNO3) using sodium citrate dihydrate (Na3C6H5O7·2H2O). The bond was formed by solid-state sintering among the individual silver NPs and solid-state bonding of these silver NPs
onto both copper wire and foil. Metallurgical bonds between silver NPs and copper were confirmed by transmission electron
microscopy (TEM). The silver NPs were coated with an organic shell to prevent sintering at room temperature (RT). It was found
that the organic shell decomposed at 160°C, the lowest temperature at which a bond could be formed. Shear tests showed that
the joint strength increased as the bonding temperature increased, due to enhanced sintering of silver NPs at higher temperatures.
Unlike low-temperature soldering techniques, bonds formed by our method have been proved to withstand temperatures above the
bonding temperature. 相似文献
Spam in online social networks (OSNs) is a systemic problem that imposes a threat to these services in terms of undermining their value to advertisers and potential investors, as well as negatively affecting users’ engagement. As spammers continuously keep creating newer accounts and evasive techniques upon being caught, a deeper understanding of their spamming strategies is vital to the design of future social media defense mechanisms. In this work, we present a unique analysis of spam accounts in OSNs viewed through the lens of their behavioral characteristics. Our analysis includes over 100 million messages collected from Twitter over the course of 1 month. We show that there exist two behaviorally distinct categories of spammers and that they employ different spamming strategies. Then, we illustrate how users in these two categories demonstrate different individual properties as well as social interaction patterns. Finally, we analyze the detectability of spam accounts with respect to three categories of features, namely content attributes, social interactions, and profile properties. 相似文献