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In this paper, we define a new closure operator on category of S-posets and study some properties of this closure operator. Also, we define the class of order vitally dense embeddings denoted by Mov, and we study the categorical properties such as product, coproduct, pushout and pullback. Next, we investigate injectivity with respect to this class of monomorphisms. [ABSTRACT FROM AUTHOR]

Best proximity point theorem furnishes sufficient conditions for the existence and computation of an approximate solution x that is optimal in the sense that the error d(x, Tx) assumes the global minimum value d(A,B). In this paper, in the setting of semi-preordered metric spaces, we introduce a new notion of hybrid weak Geraghty and Suzuki Type proximal contractions and establish certain best proximity point results for such contractions. Further, we deduce new fixed point results in semi-preordered metric spaces and discuss some illustrative examples to highlight the realized improvements. Presented theorems extend and improve certain well known results from the literature. [ABSTRACT FROM AUTHOR]

Abstract: A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20wt.% Pt/C electrocatalyst with a platinum loading of 0.4mgcm−2 was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15mAcm−2) and ESA (160m2 gr−1) than commercial Pt/C with amount of about 10mAcm−2 and 114m2 gr−1, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs. [Copyright &y& Elsevier]

The development of efficient strategies for the removal of heavy metal ions from aqueous solutions is rapidly demanded as these contaminants are very toxic and carcinogenic and show detrimental effects on the living creatures. The main focus of the current study is on the preparation and assessment of electrospun adsorptive nanofiber membranes for the removal of toxic Ni(II) and Cu(II) from wastewater in the ultrafiltration process. Hydrothermally synthesized titanate nanotubes (TNT) was modified with thiol functional groups and then directly incorporated to the polyvinyl chloride nanofiber matrices via electrospinning process to fabricate an adsorptive membrane. The as-prepared electrospun nanofiber membranes and the nanoadsorbents were characterized with respect to the physiochemical properties, surface structure and morphology, applying XPS, FTIR, FESEM, EDX and TEM analysis and then, the membranes were evaluated in terms of the removal of the heavy metal ions in a continuous ultrafiltration mode. In adsorptive filtration of the metal ions, the effective factors including nanoadsorbents loading (0.5–1.5 wt%), initial metal ion concentration (60–150 mg/L), feed temperature (~25 °C–45 °C), presence of competing ion and reusability were investigated in the UF system where the membranes containing 1.5 wt% thiol-modified TNT and virgin TNT adsorbents demonstrated excellent removal efficiency compared to the other membranes. The Cu(II) and Ni(II) removal efficiency of the membrane containing 1.5 wt% functionalized TNT was 90% and 86.7%, respectively which was the highest ones. As was expected and due to the uniform dispersion and less aggregation of the modified TNT adsorbents on the large surface area of the electrospun nanofibers, more adsorption capacity of the nanoparticles can be exploited. Moreover, the strong affinity of the thiol functional groups toward the metal cations, these membranes removed metal contaminants more efficiently. Besides, the Cu(II) removal efficiency of the fabricated membranes didn't show any drastic changes in the presence of the competing ions. Furthermore, acceptable performance was achieved for the prepared membranes even after four adsorption/regeneration cycles in the continuous UF experiments, demonstrating the feasibility and effectiveness of the prepared adsorptive nanofiber membranes for the removal of heavy metal ions. Image 1 • The hydrothermally synthesized TNT was modified by mercaptosilane coupling agent. • TNT/SH NPs were embedded into the PVC nanofiber matrices with an efficient method. • The cations removal efficiency by the membranes was evaluated in the dynamic mode. • The preference of membranes for the metal ions was in the order of Cu(II) > Ni(II). • The membranes were regenerated and reused without any significant performance loss. [ABSTRACT FROM AUTHOR]