CFRP Effect on the Buckling Behavior of Dented Cylindrical Shells

Considering that the use of thin-walled shells is expanding every day, it is important to examine the problem of instability in this form of structure. Many steel structures such as high-water tanks, water and oil reservoirs, marine structures, and pressure vessels, including shell elements, are under stress tension. In addition, shell elements are subject to instability owing to the loads applied. Ten thin-walled cylindrical shell specimens in two groups with different dent depths of t_c and 2t_c, and the different dent number subject to uniform external pressure were tested in the present research (t_c is the thickness of cylindrical shell). The samples were modified to include either one or two dent line with amplitudes of h/3 in height (h the height of cylinder shell). Moreover, CFRP Strips on the dent depth was used in one of the groups. The results of testing under different theories and codes are compared.

     

Adsorptive properties of As(III) from aqueous solution using magnetic nickel ferrite (NiFe2O4) nanoparticles: Isotherm and kinetic studies

As(III) adsorption on NiFe₂O₄ nanoparticles were systematically investigated by controlling parameters such as stirring rate, pH, initial arsenic concentration, contact duration, temperature, and adsorbent dose. It was observed that the amount of adsorbed arsenic concentration is strongly depended on pH and temperature. The temperature and pH give rise to significant changes in the amount of adsorbed arsenic. As compared with Langmuir and Freundlich isotherms models, the latter is found to be well suited. Pseudo-first order, pseudo-second order, and intraparticle diffusion models were applied to adsorption equilibrium data obtained from the analysis of arsenic with diverse amount of initial concentration.     

A classification scheme for agent based approaches to dynamic optimization

Several papers in the literature employ agent-based modeling approach for providing reasonable solutions to dynamic optimization problems (DOPs). However, these studies employ a variety of agent-based modeling approaches with different strategies and features for different DOPs. On the other hand, there is an absence in the literature of a formal representation of the existing agent-based solution strategies. This paper proposes a representation scheme indicating how the solution strategies with agent-based approach can be summarized in a concise manner. We present these in a tabular form called “Agent Based Dynamic Optimization Problem Solution Strategy” (ABDOPSS). ABDOPSS distinguishes different classes of agent based algorithms (via communication type, cooperation type, dynamism domain and etc.) by specifying the fundamental ingredients of each of these approaches with respect to problem domain (problems with dynamic objective functions, constraints and etc.). This paper also analyzes 18 generic studies in the literature employing agent-based modeling based on ABDOPSS.     

Failure Analysis of the Hydraulic Primary Standard Pressure Balance Piston

Journal of Failure Analysis and Prevention - In this study, failure analysis of piston which belongs to primary standard pressure balance unit is investigated. The strength analyses of the piston...     

Adsorption of phenol by MMT-CTAB and WPT-CTAB: Equilibrium,kinetic, and thermodynamic study

In this study, the phenol adsorption capacity of cetyltrimethylammonium bromide modified clays (MMT-CTAB) and cetyltrimethylammonium bromide modified pulp tea (WPT-CTAB) were studied. In batch adsorption experiments performed with MMT-CTAB, the effects of parameters such contact time, phenol concentration, pH of solution and adsorbent dosage were investigated. The effect of temperature on phenol adsorption onto MMT-CTAB and WPT-CTAB was examined; equilibrium and thermodynamic studies were completed. The highest phenol removal was found at pH 4.0 for MMT-CTAB and WPT-CTAB. To analyze the kinetics of phenol adsorption onto MMT-CTAB, the pseudo first-order and pseudo second-order kinetic models were applied. The kinetic data fitted better to the pseudo second-order model than the pseudo first-order kinetic model for MMT-CTAB. The characterization of adsorbents in phenol adsorption was clarified with the FTIR technique. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated for each adsorption process. The adsorption process was found to be exothermic and spontaneous for phenol adsorption by MMT-CTAB and WPT-CTAB. The results were analyzed with the Langmuir, Freundlich, Temkin and Harkins–Jura equations using linearized correlation coefficients at different temperatures. The Langmuir equation was found to best represent the equilibrium data for phenol adsorption onto MMT-CTAB and WPT-CTAB.     

A new clustering method based on the bio-inspired cuttlefish optimization algorithm

Most of the well-known clustering methods based on distance measures, distance metrics and similarity functions have the main problem of getting stuck in the local optima and their performance strongly depends on the initial values of the cluster centers. This paper presents a new approach to enhance the clustering problems with the bio-inspired Cuttlefish Algorithm (CFA) by searching the best cluster centers that can minimize the clustering metrics. Various UCI Machine Learning Repository datasets are used to test and evaluate the performance of the proposed method. For the sake of comparison, we have also analysed several algorithms such as K-means, Genetic Algorithm and the Particle Swarm Optimization (PSO) Algorithm. The simulations and obtained results demonstrate that the performance of the proposed CFA-Clustering method is superior to the other counterpart algorithms in most cases. Therefore, the CFA can be considered as an alternative stochastic method to solve clustering problems.     

Novel Polymer-Bentonite Sorbent for Recovery of Antioxidant Polyphenols from Cornus mas L. through Integrated Process Extraction/Adsorption: Optimization of Extraction Parameters by Response Surface Methodology

Here, ultrasound-assisted extraction with ultrasonic probe of total polyphenolic content from leaves of cornelian cherry (Cornus mas L.) was studied. Batch adsorption was carried out to concentrate polyphenol extract using bentonite/2-(dimethyl amino) ethyl methacrylate composite adsorbent. The extraction was optimized through face central composite design combined with response surface methodology. It was found that bentonite/2-(dimethyl amino) ethyl methacrylate composite exhibits significant adsorption capacity (2407.50 mg-GAE/g-bentonite/2-(dimethyl amino) ethyl methacrylate composite) for polyphenols in cornelian cherry leaves. It was observed that pH was the crucial factor and highest adsorption capacity was obtained at pH 10.     

Effects of Ultrasonication and Aqueous Ozonation on Gelatinization and Flow Properties of Potato Starch

Ultrasonication and aqueous ozonation were applied to potato starch simultaneously. Flow properties (i.e., flow behavior index, n; consistency index, K; and apparent viscosity, η_app) of samples were determined using a rheometer. A differential scanning calorimeter (DSC) was used to measure the gelatinization properties of samples (onset, peak and conclusion gelatinization temperatures and enthalpy of gelatinization). Results showed that ozonation caused a significant increase (p < 0.05) in onset gelatinization temperature (from 54.9 to 59.1 °C) and a significant decrease (p < 0.05) in enthalpy of gelatinization (from 14.6 to 12.2 J/g). There were no significant differences (p < 0.05) between the consistency index (ranged from 4.57 to 4.87 Pas) and apparent viscosity (ranged from 0.10 to 0.13 Pas) of samples treated with ozonation and ultrasonication with no regards of treating sequence. This showed that the order of treatment (i.e., ozonation and ultrasonication) does not have any significant effect on the flow properties of potato starch studied under the conditions applied in this research.     

Effect of Fenton's reagent on the degradability of CI Reactive Yellow 15

As an advanced oxidation method, Fenton's reagent has an advantage that it combines both oxidation and coagulation techniques. The aim of this study was to efficiently operate Fenton's reagent oxidation to degrade a reactive dye, CI Reactive Yellow 15, which is non-biodegradable and has high chemical oxygen demand. In addition, performance of the Fenton oxidation process for dye solution was determined by measuring the chemical oxygen demand and colour removal. The influence of the main operating parameters, iron sulphate and hydrogen peroxide concentration, pH, temperature and dye concentration have been studied, in a batch-type operation. The results obtained show that the best pH value for decolorisation was pH 3, with an average decolorisation of 98.7% and average removal of chemical oxygen demand ca. 93.3% at 15 °C for a 0.065 molar ratio of Fenton's reagent. An increase in temperature resulted in higher removal rates.