Removal of brilliant blue pollution from the environment using nano polyaniline hazelnut skin composite and evaluation of effective parameters

The entrance of household wastewater to rivers has not only brought about numerous environmental problems, which have resulted in a huge problem in the society, but also led to undesirable mental and psychological effects in the society. The removal of dye from these wastewaters before entrance to rivers is of great importance. In this research, it was discovered that by depositing a layer of polyaniline-based conductive nano polymer on hazelnut skin, a nano composite was produced which helps in removing brilliant blue (BB) dye from aqueous environments. The aim of this study was to deposit a layer of polyaniline nano polymer on the surface of hazelnut skin and produce polyaniline/hazelnut skin (Pan/Hz) composite through chemical polymerization of aniline in aqueous environments and adsorption of BB dye from aqueous environments. In this stage, polyaniline was synthesized using ammonium persulfate. In order to find the optimal conditions for the removal of the dye, the effect of a number of important parameters such as pH, contact time, initial concentration of the dye, and temperature was examined. Langmuir and Freundlich isotherms were used for adsorption studies. Furthermore, thermodynamic and kinetic studies were also conducted. This dye has the greatest adsorption at pH 2 and by optimizing other mentioned parameters, the best state has been presented for maximum adsorption. Thermodynamic studies indicate that the adsorption has been spontaneous, endothermic, and chemical, following the second order kinetics. The introduced adsorbent is a very effective one for the adsorption of BB and by using a layer of conductive nano polymer on hazelnut skin, it is possible to absorb BB dye from aqueous environments with a very high percentage

Railway-induced ground vibrations – a review of vehicle effects

This paper is a review of the effect of vehicle characteristics on ground- and track borne-vibrations from railways. It combines traditional theory with modern thinking and uses a range of numerical analysis and experimental results to provide a broad analysis of the subject area. First, the effect of different train types on vibration propagation is investigated. Then, despite not being the focus of this work, numerical approaches to vibration propagation modelling within the track and soil are briefly touched upon. Next an in-depth discussion is presented related to the evolution of numerical models, with analysis of the suitability of various modelling approaches for analysing vehicle effects. The differences between quasi-static and dynamic characteristics are also discussed with insights into defects such as wheel/rail irregularities. Additionally, as an appendix, a modest database of train types are presented along with detailed information related to their physical attributes. It is hoped that this information may provide assistance to future researchers attempting to simulate railway vehicle vibrations. It is concluded that train type and the contact conditions at the wheel/rail interface can be influential in the generation of vibration. Therefore, where possible, when using numerical approach, the vehicle should be modelled in detail. Additionally, it was found that there are a wide variety of modelling approaches capable of simulating train types effects. If non-linear behaviour needs to be included in the model, then time domain simulations are preferable, however if the system can be assumed linear then frequency domain simulations are suitable due to their reduced computational demand

Three-dimensional modelling of high speed ballasted railway tracks

In the present paper, a three-dimensional dynamic railway finite-element model, is utilised to study the geotechnical performance of high speed railway tracks. This model takes into account many of the railway track components such as multi-layered ballast and subgrade, nonlinearity in resilient behaviour of the sub-soil, and track–train interaction. Different features of the developed model are briefly presented. The effects of train speed, ballast and subgrade stiffness, and nonlinearity of the soil behaviour are then investigated. The results of the numerical simulations regarding the track response and required maintenance levels, in terms of the stress and vibration level experienced by the ballast and subgrade are also discussed and compared to site measurements. Track design methods are also reviewed, and a design method based on the dynamic finite-element analysis is proposed and discussed, which aims at minimising railway track maintenance levels by protecting the subgrade from dynamic ground amplification for speeds approaching the Rayleigh wave velocity, and also aims at minimising ballast maintenance by setting a maximum ballast particle velocity. </jats:p

Synthesis of Nano Conducting Polymer Based Polyaniline and it's Composite: Mechanical Properties, Conductivity and Thermal Studies

Polyaniline (PAn) was prepared chemically in the presence of bronsted acid from aqueous solutions. Polyaniline- nylon 6 composite (termed as PAn/Ny6) prepared via solvent casting method. The preparation conditions were optimized with regard to the mechanical properties of the polymer composite. It was found that the molar ratio of PAn to nylon have the greatest effect in determining the mechanical properties of polymer composite. Electrical conductivity was measured using standard method of four point probe. Spectrophotometric analysis (UV-Vis) was used for investigation of the effect of thermal treatment on polyaniline and it’s composite