Fabrication of platinum coated nanoporous gold film electrode: A nanostructured ultra low-platinum loading electrocatalyst for hydrogen evolution reaction

The electrolytic hydrogen evolution reaction (HER) on platinum coated nanoporous gold film (PtNPGF) electrode is demonstrated. The deposition of platinum occurred as a spontaneous redox process in which a copper layer, obtained by underpotential deposition, was oxidized by platinum ions, which were reduced and simultaneously deposited. The present method could provide a very low Pt-loading electrode and the results demonstrated that ultra thin Pt coating effected efficiently and behaved as the nanostructured Pt for electrocatalytic hydrogen evolution reaction. The loading of Pt was calculated as 4.2 × 10⁻³ μg cm⁻² for PtNPGF electrode. The current density at −0.4 V and −0.8 V vs. Ag/AgCl was as high as 0.66 A μg⁻¹ Pt and 3 A μg⁻¹ Pt, respectively and the j₀ was evaluated as 0.03 mA cm⁻² or 8 mA μg⁻¹ Pt. The results indicated that increasing electrode area had no catalytic effect, but the nanostructure nature of as-fabricated electrode and submonolayer deposition of copper resulted in electrocatalytic activity for PtNPGF electrode.     

Evaluating knowledge management failure factors using intuitionistic fuzzy FMEA approach

The twenty-first century organizations are characterized by an emphasis on knowledge and information. Today’s organizations also require the acquisition, management, and exploitation of knowledge and information in order to improve their own performance. In the current economy, the foundations of organizational competitiveness have turned former tangible and intangible resources into knowledge and the focus of information systems has also changed from information management to knowledge management. Besides, the most important step in the implementation of knowledge management is to examine the significant factors in this regard and to identify the causes of failure. Therefore, the present study evaluated knowledge management failure factors in an intuitionistic fuzzy environment as a case study in Khuzestan Oil and Gas Company. For this purpose, a series of failure factors affecting knowledge management in organizations were identified based on a review of the related literature and similar studies. Then, 16 failure factors in the implementation of knowledge management in the given organization were determined on the basis of interviews with company experts. According to the specified factors as well as the integration of multiple criteria decision-making techniques in an intuitionistic fuzzy environment, knowledge management failure factors in Khuzestan Oil and Gas Company were investigated. The results indicated that lack of management commitment and leadership was the most important factor affecting the failure of knowledge management in the given company.     

Security enhancements against UMTS–GSM interworking attacks

In this paper we first present three new attacks on Universal Mobile Telecommunication System (UMTS) in access domain. We exploit the interoperation of UMTS network with its predecessor, Global System for Mobile communications (GSMs). Two attacks result in the interception of the entire traffic of the victim UMTS subscriber in the GSM access area of UMTS network. These attacks are applicable, regardless of the strength of the selected GSM encryption algorithm. The third attack is an impersonation attack and allows the attacker to impersonate a genuine UMTS subscriber to a UMTS network and fool the network to provide services at the expense of the victim subscriber. Then, we propose some countermeasures to strengthen the UMTS network against the mentioned attacks with emphasis on the practicality in present networks. The proposed solutions require limited change of the network elements or protocols, insignificant additional computational load on the network elements and negligible additional bandwidth consumption on the network links.     

An electrochemical sensor based on V2O5 nanoparticles for the detection of ciprofloxacin

This research constructed and utilized a screen-printed electrode (SPE) modified with V₂O₅ nanoparticles (NPs) (V₂O₅/SPE) employed in order to sensitively and selectively quantify ciprofloxacin with exceptional accuracy in the phosphate buffer solution (PBS) with the use of differential pulse voltammetry (DPV). Moreover, electrochemical properties of this new V₂O₅/SPE sensor have been examined using diverse characterization procedures. Very good V₂O₅/SPE electrochemical features offered sensitive ciprofloxacin voltammetric determination with the reduced limit of detection (LOD?=?0.01 µM) toward electrocatalytic oxidation of ciprofloxacin in comparison with the bare SPE. Finally, this new disposable sensor exhibited higher sensitivity and thus has been efficiently utilized to determine ciprofloxacin in the real samples.

     

Evaluation of ‘green’ synthesis and biological activity of gold nanoparticles using Tragopogon dubius leaf extract as an antibacterial agent

Currently, the use of ‘green’ synthesised nanoparticles with environmentally friendly properties is considered a novel therapeutic approach in medicine. Here, the authors evaluated gold nanoparticles (AuNPs) conjugated with Tragopogon dubius leaf extract and their antibacterial activity in vitro and in vivo. Colour changes from yellow to dark brown and a peak at 560 nm on ultraviolet–visible spectroscopy confirmed the formation of nanoparticles. Additionally, transmission electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy analyses were performed to determine particle sizes and functional groups involved in gold reduction. Moreover, using standard micro‐dilution and disc‐diffusion assays against Klebsiella pneumoniae, Bacillus cereus, Escherichia coli, and Staphylococcus aureus, the antimicrobial properties of synthesised AuNPs were investigated. To confirm antibacterial activity, synthesised AuNPs were applied in a rat model on burn wounds infected with S. aureus, and the nanoparticles were as effective as tetracycline in bacterial reduction and wound healing. In conclusion, the synthesis of AuNPs with aqueous T. dubius extract was rapid, simple, and inexpensive, and the synthesised nanoparticles had significant antibacterial activity in vitro and in vivo.Inspec keywords: transmission electron microscopy, wounds, nanoparticles, ultraviolet spectra, reduction (chemical), particle size, nanofabrication, gold, X‐ray diffraction, antibacterial activity, microorganisms, visible spectra, nanomedicine, biomedical materials, Fourier transform infrared spectraOther keywords: biological activity, gold nanoparticles, antibacterial agent, therapeutic approach, colour changes, ultraviolet–visible spectroscopy, transmission electron microscopy, gold reduction, antimicrobial properties, Fourier transform infrared spectroscopy analyses, disc‐diffusion assay, green synthesis, Tragopogon dubius leaf, in vitro antibacterial activity, in vivo antibacterial activity, X‐ray diffraction, particle sizes, functional groups, standard microdilution assay, burn wounds, S. aureus, tetracycline, bacterial reduction, wound healing, wavelength 560.0 nm     

Interconnection-based performance analysis for a class of decentralized controllers

This paper is concerned with decentralized controller design for large-scale interconnected systems of pseudo-hierarchical structure. Given such a system, one can use existing techniques to design a decentralized controller for the reference hierarchical model, obtained by eliminating certain weak interconnections of the original system. Although this indirect controller design is appealing as far as the computational complexity is concerned, it does not necessarily result in satisfactory performance for the original pseudo-hierarchical system. An LQ cost function is defined in order to evaluate the performance discrepancy between the pseudo-hierarchical system and its reference hierarchical model under the designed decentralized controller. A discrete Lyapunov equation is then solved to compute this performance index. However, due to the large-scale nature of the system, this equation cannot be handled efficiently in many real-world systems. Thus, attaining an upper bound on this cost function can be more desirable than finding its exact value, in practice. For this purpose, a novel technique is proposed which only requires solving a simple LMI optimization problem with three variables. The problem is then reduced to a scalar optimization problem, for which an explicit solution is provided. It is also shown that when the original model is exactly hierarchical, then the upper bounds obtained from the LMI and scalar optimization problems will both be equal to zero.     

Utilization of textile wastewater as carbon source by newly isolated <Emphasis Type="Italic">Haloarcula</Emphasis> sp<Emphasis Type="Italic">.</Emphasis> IRU1: optimization of conditions by Taguchi methodology

Wastewater of textile industry is one of the most important threats to the environment and human health. The Taguchi methodology was applied to optimize conditions for the growth of a novel Haloarcula sp. IRU1 with a textile wastewater as carbon source by evaluating the influence of temperature, concentration of textile wastewater and pH on biomass of Haloarcula sp. IRU1. We intended to evaluate biodegradation ability of this bacterium. Highest biomass of Haloarcula sp. IRU1 was achieved at temperature 47°C, concentration of textile wastewater 7% v/v and pH 9. In conclusion, the isolated halophilic bacterium Haloarcula sp. IRU1 can utilize textile wastewater as carbon source and biodegrade it in different conditions.