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1.
Experimental and MD simulation study on the physical and mechanical properties of organically modified montmorillonite clay and compatibilized linear low density polyethylene nanocomposites 下载免费PDF全文
Understanding the interfacial interactions plays a key role in controlling mechanical and physical properties of polymer/clay nanocomposites (PCNs). In this work, the surface interactions between constituents of experimentally prepared PCNs which are the pristine linear low density polyethylene (PE) chains, PE compatibilizers, montmorillonite clay surface layer, and surfactants were studied quantitatively by employing molecular dynamics simulation technique. The interaction energy between the polymer and the clay was found to be inversely proportional with the volume of the surfactant which decreases the electrostatic interactions between the compatibilizer and the hydrophilic clay surface. However, the van der Waals (vdW) interactions between alkyl tails of surfactants and the PE chains increase with the tail length of the surfactants. The most attractive interaction was between the surfactant's head group and the clay surface. We showed that there existed fine balance between the electrostatic and vdW type forces on the stability and the enhanced properties of the PE–organoclay nanocomposites. Calculated interaction energies were then correlated to the experimentally measured mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45817. 相似文献
2.
ABSTRACTWind turbine control is an important task to make the electricity generation secure in terms of energy demand and machine safety. It also yields to control the desired power level and optimized energy because of the assignment of turbine speed. The contactless piezoelectric wind energy harvester (CPWEH) used in this study has three piezoelectric layers located around the shaft with 120 degrees apart and they are buckled by the magnetic force without any physical contact. The superiority of this device is to generate energy for low wind speeds such as 1.5 m/s. However, for high speeds, high total harmonic distortions (THDs) govern the waveforms, thus controlling the turbine speed becomes necessary for optimizing the output power. Encouraged by this, a small low inertia dc generator is coupled with the wind turbine, and the generator terminals are connected to a resistor through a power switch to generate a braking torque that opposes to wind speed direction. By controlling the switch properly, turbine speed is ensured to remain within a certain band, which accordingly prevents the turbine from rotating very fast at damaging wind speeds. Several experiments are performed on the developed CPWEH with/without the presented control scheme which prove the existence of promising performance of our proposal. 相似文献
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4.
The Journal of Supercomputing - In recent years, deep artificial neural networks can have better forecasting performance than many other artificial neural networks. The long short-term memory... 相似文献
5.
Ozdemir Erdem Tevfik Kartal Ugur Dikici Tuncay Erol Mustafa Yurddaskal Metin 《Journal of Materials Science: Materials in Electronics》2021,32(23):27398-27408
Journal of Materials Science: Materials in Electronics - In this study, zinc oxide (ZnO) nanowires (NWs) were successfully produced on Zn plates through electrochemical anodization in potassium... 相似文献
6.
Nanofibers and films of poly(3‐hydroxybutyrate) (PHB)/nylon 3 [poly(β‐alanine) (N3)], PHB/poly(α‐methyl‐β‐alanine) (2mN3), and PHB/poly(β‐methyl‐β‐alanine) (3mN3) blends were prepared by electrospinning and film‐casting techniques, respectively. The miscibility of the blends was studied by Fourier transform infrared spectrometry, differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction (XRD). The electrospinnability of the blends was studied by scanning electron microscopy. Some characteristic IR absorption bands of the components in the blends shifted gradually with changes in the compositions. The melting temperature and decomposition temperature of PHB decreased gradually with increasing fractions of N3, 2mN3, and 3mN3. The XRD spectra of all of the blends exhibited peaks with lower intensities compared to those of the neat species. The suppression of PHB crystallinity in the blends after blending was attributed to the disruption of its crystal lattice and the prevention of recrystallization of each component by means of other components and segmental interactions between the components in the amorphous phase. Thermal, spectroscopic, and optical analyses of the polymer blends revealed that the polymers were miscible with good compatibility, and this could have improved the scaffold properties of PHB. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40484. 相似文献
7.
Emine Acer Emin Çadırlı Harun Erol Hasan Kaya Mehmet Gündüz 《Metallurgical and Materials Transactions A》2017,48(12):5911-5923
Dendritic spacing can affect microsegregation profiles and also the formation of secondary phases within interdendritic regions, which influences the mechanical properties of cast structures. To understand dendritic spacings, it is important to understand the effects of growth rate and composition on primary dendrite arm spacing (λ 1) and secondary dendrite arm spacing (λ 2). In this study, aluminum alloys with concentrations of (1, 3, and 5 wt pct) Zn were directionally solidified upwards using a Bridgman-type directional solidification apparatus under a constant temperature gradient (10.3 K/mm), resulting in a wide range of growth rates (8.3–165.0 μm/s). Microstructural parameters, λ 1 and λ 2 were measured and expressed as functions of growth rate and composition using a linear regression analysis method. The values of λ 1 and λ 2 decreased with increasing growth rates. However, the values of λ 1 increased with increasing concentration of Zn in the Al-Zn alloy, but the values of λ 2 decreased systematically with an increased Zn concentration. In addition, a transition from a cellular to a dendritic structure was observed at a relatively low growth rate (16.5 μm/s) in this study of binary alloys. The experimental results were compared with predictive theoretical models as well as experimental works for dendritic spacing. 相似文献
8.
Hakan Çiftçi Uğur Tamer Aysegül Ü. Metin Erol Alver Nevin Kizir 《Journal of Applied Electrochemistry》2014,44(5):563-571
This study outlines a new sensing platform based on glassy carbon electrodes modified by gold nanoparticles (AuNPs) for the determination of heavy metal. A glassy carbon electrode was modified by chitosan stabilized AuNPs. AuNPs were prepared by reducing gold salt with a polysaccharide chitosan. Here, chitosan acted as a reducing/stabilizing agent. The AuNPs were characterized with UV–Visible absorption spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. Chitosan covered AuNPs were immobilized on the glassy carbon electrode for the determination of Cu (II) in aqueous solutions. The electrochemical determination of Cu (II) ions was performed using the differential pulse voltammetry technique. Some parameters for Cu (II) determination, such as pH, preconcentration time and electrolysis potential of Cu (II), were optimized. The detection limit was calculated as 5 × 10?9 mol L?1 by means of the 3:1 current-to-noise ratio. The interference of Cr(III), Fe(II), Ni(II), Pb(II), Mg(II), Zn(II), Ba(II) ions was investigated and showed a negligible effect on the electrode response. Recovery studies were carried out using tap water. 相似文献
9.
Fuzzy time series approaches are used when observations of time series contain uncertainty. Moreover, these approaches do not require the assumptions needed for traditional time series approaches. Generally, fuzzy time series methods consist of three stages, namely, fuzzification, determination of fuzzy relations, and defuzzification. Artificial intelligence algorithms are frequently used in these stages with genetic algorithms being the most popular of these algorithms owing to their rich operators and good performance. However, the mutation operator of a GA may cause some negative results in the solution set. Thus, we propose a modified genetic algorithm to find optimal interval lengths and control the effects of the mutation operator. The results of applying our new approach to real datasets show superior forecasting performance when compared with those obtained by other techniques. 相似文献
10.
ABSTRACT The development of improved methods of grinding and separation of fine particles is becoming increasingly important in a wide variety of industries. The requirements on the powder production differ widely, and depend on both the material and the specific application. This paper describes the effects of a variety of parameters on the production of fine powder by dry grinding; these parameters include particle agglomeration, the classification method employed, and air moisture in the mill. It is also demonstrated that particle shape is affected by the type of machine, by the specific breakage mechanism in a grinding device, and by the time spent in the grinding environment. 相似文献