Novel synthesis and characterization of cobalt titanate nanoparticles: investigation of capping agents effect and its photocatalyst application

This work has provided a general, simple, and effective method to control the composition and morphology of CoTiO₃ nanoparticles, which revealed potential new insight into inorganic synthesis methodology. CoTiO₃ nanoparticles were synthesized via a novel route based on the reaction between cobalt salt and tetra-n-butyl titanate (TNBT) in ethanol. Results of this investigation demonstrate that CoTiO₃ with very uniform sphere-like shape, small grain size and pure rhombohedral phase could be synthesized by different capping agents such as asparagine, alanine, and leucine. XRD, SEM, EDS, and UV–vis spectroscopy were employed to characterize structural, morphological, and optical properties of CoTiO₃ nanoparticles. According to the vibrating sample magnetometer (VSM) result, CoTiO₃ nanoparticles indicated a paramagnetic behavior at room temperature. Furthermore, the photocatalytic properties of as synthesized CoTiO₃ were evaluated by degradation of methyl orange (MO) as water contaminant.     

Preparation of synthesized sulfide polymer through phase-transfer catalyzed polycondensation of ethylene dibromide and sodium tetrasulfide: characterization,thermal and rheological properties

Sulfide polymers were obtained through the interfacial polymerization of sodium tetrasulfide and ethylene dibromide. The polymerization process was carried out under interfacial condition using two phase-transfer catalysts: methyl-tributyl ammonium bromide and methyl-tributyl ammonium chloride. The polymer characteristics were examined by attenuated total reflectance- fourier transform infrared spectroscopy, elemental analysis (CHNS/O) and X-ray diffraction methods. Thermal characteristics were investigated by differential scanning calorimetry and thermogravimetric analysis methods. The rheological behavior of the synthesized sulfide polymer during curing reaction, and isothermal time dependency of elastic storage modulus, G^′, at different temperatures and constant shear frequency was studied using a stress-controlled rheometer. Moreover, the solvent resistance of synthesized polymer was investigated through the swelling method.     

Direct air capture from demonstration to commercialization stage: A bibliometric analysis

Concerns related to increasing CO₂ emission and its effects on global warming and climate change have been increased with increasing the global consumption of fossil fuels. One solution to respond to this challenge is the development and utilization of carbon capturing and storage technologies. Among different carbon capturing technologies, direct air capture (DAC) reduces CO₂ emissions from air. While the technology readiness level (TRL) of DAC is in the demonstration stage, identifying the commercialization research gaps and possible opportunities can help with diffusion and adoption of the technology. This research uses a knowledge discovery in research databases, based on bibliometric analysis and data mining, to understand DAC research and development's current status and future. Then, we identify the critical areas of the research gap for commercialization. The bibliometric analysis results show that DAC has not yet reached its maturity level compared with other carbon capture technologies (CCTs). However, there are different opportunities for the development of this technology. The results indicate that (a) new systematic designs, improvement in nano-catalysts, increase in the capturing capacity, (b) economic and investment improvements in combination with the environmental assessment of the optimized DAC technology, (c) assessment of future prospects, (d) integration with alternative energy supply sources especially renewable energy to respond to the required energy and process integration with current carbon emitted processes, (e) technology demonstration and readiness assessment, and (f) policy and uncertainty analysis of the market are the key areas that should be investigated for the success of this technology in the competitive market.     

Using sticker model of DNA computing to solve domatic partition, kernel and induced path problems

DNA computing as a powerful interdisciplinary field has been found to be very useful and applicable for solving NP-complete and intractable problems because of its huge power in parallel processing. In recent years many efforts have been done to solve NP-complete and time consuming problems with the help of DNA computing. In this paper, we use sticker model (one of the most well-known models of DNA computing) to present three DNA algorithms for solving three different NP-complete graph-based problems for the first time: domatic partition, kernel and induced path. Also we have simulated these algorithms to show their correctness.     

Recent advances in core/shell bicomponent fibers and nanofibers: A review

There has been a steady progress in developing synthetic fibers in the past few years. Bicomponent fibers and nanofibers in a core/shell (C/S) configuration, including two dissimilar materials have presented unusual potential for use in many novel applications. These fibers can be produced using a variety of materials via different techniques i.e., coaxial melt spinning and electrospinning. In this review, we discuss the recent advances in C/S fibers and nanofibers’ production. The first part has been assigned to the bicomponent fibers manufacturing technology, while production and applications of C/S nanofibers have been described in the second part. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46265.     

pH-responsive polymer in a core–shell magnetic structure as an efficient carrier for delivery of doxorubicin to tumor cells

A pH-responsive polymer derived from polyethyleneimine with zwitterionic function was used as a shell around super paramagnetic iron oxide nanoparticles (SPIONs), to introduce an efficient drug carrier for cancer drug delivery and imaging. Core–shell magnetic Fe₃O₄@FA-PEI-SUC (SUC: Succinate conjugated) nanoparticles were attained and characterized. Right chemical attachments, 61.34% modification of primary amino groups of poly(ethyleneimine) (PEI) in PEI–SUC, spherical shape, core–shell structure, crystal structure of SPIONs, 18.23% polymer coating of NPs, 8% decrease in magnetization following polymer coating around SPIONs, doxorubicin loading efficiency 85.19%, two times more released amount in acidic pH, and proper toxicity results were obtained by different analysis methods.     

Authentication systems: A literature review and classification

One of the most important parts of any system is authentication. Appreciated as the first and the last line of defense in the great majority of cases, authentication systems can usually prevent the kleptomaniac from unauthorized accessing to users’ data. However, the traditional text-based password is still used in many websites and applications which are vulnerable to different kinds of attacks. Accordingly, there exist some other alternative ways to boost this traditional method. In this study, we classified and identified different types of authentication systems in a variety of platforms. Their usage, similarity, usability, performance and drawbacks were discussed. The goal of this study is to provide useful, classified information with the aim of understanding of how different authentication systems work and of what their usability and drawbacks are to the readers.     

Comments on: “Fault detection for continuous‐time switched systems under asynchronous switching”

In this note, a defect occurred in Theorem 1 in the study Du et al. (Int. J. Robust Nonlinear Control 2013; doi: 10.1002/rnc.2961) is addressed. Additionally, the correction of the theorem is presented. Copyright © 2014 John Wiley & Sons, Ltd.     

Seismic performance of an innovative structural system having seesaw motion and columns equipped with friction dampers at base level

Most seismic design codes accept heavy damages to buildings in case of large earthquakes, provided that they are prevented against collapse. However, this leads to unacceptable consequences, such as very large volume of the required reconstruction works, in large populated cities. One way to get rid of these adverse consequences is using the idea of combining rocking/seesaw motion of the building's structure and energy dissipation at base level to create buildings easily repairable even after a large earthquake. In the present study, this idea has been employed for designing steel buildings with seesaw motion capability by using a central massive column at ground floor, with elastic behavior and other columns at that floor quipped with friction dampers. A set of buildings has been designed, once based on the conventional provisions and once by using the suggested structural system. Then, a set of nonlinear time history analyses have been performed on all buildings by using selected earthquake records. Results show that the suggested structural system has reliable seismic behavior, so that large deformations happen only in columns at ground floor which have telescopic motion because of the friction dampers, as such, these buildings can be easily repaired even after large earthquakes. Copyright © 2016 John Wiley & Sons, Ltd.     

Design and fabrication of a novel vibrational system for ultrasonic assisted oblique turning process

We designed and fabricated suitable vibrational equipment for ultrasonic assisted oblique turning process to enable researchers to perform experimental tests with the operating conditions closest to common assumptions of cutting mechanics theories. Applying ultrasonic vibrations to the tool cutting edge along tangential direction and in the presence of inclination and tool cutting edge angles necessitates a novel design and fabrication of vibrational horn with special oblique geometry. In this vibrational horn, the natural frequency of longitudinal vibration mode is forced to be in a certain frequency range of the ultrasonic power supply. The novel tool-workpiece assembly was designed using modal analysis to provide the most conformity of cutting geometry and process parameters between theory and practice. Three-dimensional cutting forces were measured experimentally in vibrational oblique turning process carried out by the mentioned horn. The most suitable conditions to profit from ultrasonic vibrations in oblique turning process were determined, and these experimental results were in agreement with modal analysis results.