Simulation of UV photoreactor for water disinfection in Eulerian framework

A novel computational fluid dynamic (CFD) modeling procedure was developed in order to simulate ultraviolet (UV) photoreactors in the Eulerian framework. In this procedure, the governing equations of radiation distribution, mass conservation, momentum conservation, and species mass conservation are solved together in order to determine the radiant energy field, velocity field, and the concentration profile of microorganisms at steady state conditions. The general method presented can be employed to derive the volumetric inactivation rate and the theoretical efficiency of a UV photoreactor. The integrated CFD model of UV photoreactor performance was successfully evaluated with experimental biodosimetry results. The verified procedure can be applied to the simulation and design optimization of UV photoreactors with different geometries and operating conditions.     

Optimal design of real‐size building structures using quantum‐behaved developed swarm optimizer

In this paper, the quantum‐behaved developed swarm optimizer is proposed for optimal design of real‐size building structures in which the quantum computing is introduced into the standard developed swarm optimizer. In this method, the position‐updating process for the search agents is conducted by simultaneous utilization of the so far best position of all particles, center of mass of all particles, so far best position of each particle, and the mean best position of all particles in which the first two of these aspects satisfy the exploration phase of the algorithm, whereas the other two are utilized for improving the exploitation phase of the proposed method. In order to evaluate the capability of the proposed method in dealing with difficult optimization problems, three real‐size building structures are considered, namely, a 10‐story building with 1,026 structural members, a 20‐story building with 3,860 members, and a 60‐story building with 8,272 members. The overall performance of the proposed quantum‐behaved developed swarm optimizer is compared with that of the standard developed swarm optimizer and other approaches. The obtained results proved that the proposed method is capable of providing better results for the considered examples than are the other algorithms.     

Improved dynamic equations for the generally configured Stewart platform manipulator

In this paper, a Newton-Euler approach is utilized to generate the improved dynamic equations of the generally configured Stewart platform. Using the kinematic model of the universal joint, the rotational degree of freedom of the pods around the axial direction is taken into account in the formulation. The justifiable direction of the reaction moment on each pod is specified and considered in deriving the dynamic equations. Considering the theorem of parallel axes, the inertia tensors for different elements of the manipulator are obtained in this study. From a theoretical point, the improved formulation is more accurate in comparison with previous ones, and the necessity of the improvement is clear evident from significant differences in the simulation results for the improved model and the model without improvement. In addition to more feasibility of the structure and higher accuracy, the model is highly compatible with computer arithmetic and suitable for online applications for loop control problems in hardware.     

Dynamic mechanical behavior and nanostructure morphology of hyperbranched‐modified polypropylene blends

Polypropylene (PP) was modified utilizing two types of polyesteramide‐based hyperbranched polymers (amphiphilic PS and hydrophilic PH). A maleicanhydride‐modified PP (PM) was used as a reactive dispersing agent to enhance the modification by grafting the hyperbranched polymers onto the PP chains. Pure PP, two different non‐reactively modified samples, i.e. excluding PM, and two different reactively modified samples, i.e. including PM, were studied. Investigating the morphology of the samples was performed by scanning electron microscopy. To follow the effect of the modification on the dynamic mechanical properties, dynamic mechanical analysis experiments both in the melt (rheometric mechanical spectrometry) and in solid state (dynamic mechanical thermal analysis) were carried out. In the next step, the nanocrystalline structure of the samples was studied by small angle X‐ray scattering (SAXS) in two different modes, i.e. static and recrystallization. Hundreds of SAXS patterns were analyzed automatically using procedures written in PV‐WAVE image‐processing software. The chord distribution function (CDF) was calculated and the long period (l_p) of the crystal lamellae was extracted from the CDFs. The rheometric mechanical spectrometry results show that both hyperbranched polymers decrease complex viscosity η^* and enhance liquid‐like behavior. This happens more significantly when PM is included. The dynamic mechanical thermal analysis results reveal that T_g decreases when PS and PH are added. In the reactively modified samples this reduction is compensated most probably because of the crosslinked structure formed through the grafting reaction between the hyperbranched polymers and PM. Such structure is confirmed by SAXS data and calculated CDFs in the recrystallization mode. Static SAXS data also show enhancement in the crosshatched morphology of the crystalline lamellae of PP for reactively modified samples compared with non‐reactively modified samples. © 2013 Society of Chemical Industry     

On the Influence of Crosslinker on Template Complexation in Molecularly Imprinted Polymers: A Computational Study of Prepolymerization Mixture Events with Correlations to Template-Polymer Recognition Behavior and NMR Spectroscopic Studies

Aspects of the molecular-level basis for the function of ethylene glycol dimethacrylate and trimethylolproprane trimethacrylate crosslinked methacrylic acid copolymers molecularly imprinted with (S)-propranolol have been studied using a series of all-component and all-atom molecular dynamics studies of the corresponding prepolymerization systems. The crosslinking agents were observed to contribute to template complexation, and the results were contrasted with previously reported template-recognition behavior of the corresponding polymers. Differences in the extent to which the two crosslinkers interacted with the functional monomer were identified, and correlations were made to polymer-ligand recognition behavior and the results of nuclear magnetic resonance spectroscopic studies studies. This study demonstrates the importance of considering the functional monomer–crosslinker interaction when designing molecularly imprinted polymers, and highlights the often neglected general contribution of crosslinker to determining the nature of molecularly imprinted polymer-template selectivity.     

Design optimization of truss structures using cuckoo search algorithm

A new metaheuristic optimization algorithm is developed to solve truss optimization problems. The new algorithm, called cuckoo search (CS), is examined by solving five truss design optimization problems with increasing numbers of design variables and complexity in constraints. The performance of the CS algorithm is further compared with various classical and advanced algorithms, selected from a wide range of the state‐of‐the‐art algorithms in the area. The results identify that the final solutions obtained by the CS are superior compared with the best solutions obtained by the other algorithms. Finally, the unique search features used in the CS and the implications for future researches are discussed in detail. Copyright © 2012 John Wiley & Sons, Ltd.     

Wall Smoke Deposition from a Hot Smoke Layer

Smoke deposition from a hot smoke layer onto wall surfaces was studied in a hood apparatus using polymethylmethacrylate, polypropylene, and gasoline as fuels. Based upon prior analysis by Butler and Mulholland, the smoke deposition was expected to be dominated by thermophoresis. The deposited smoke samples were collected on glass filter paper attached to the hood wall and the mass per unit area of smoke deposited was measured gravimetrically. Measurements were made of quantities required for the prediction of thermophoretic smoke deposition. The smoke deposition measured in the experimental program was well predicted by the thermophoretic smoke deposition equation. The thermophoretic smoke deposition equation was found to be suitable for predicting smoke deposition onto wall surfaces exposed to fire environments.     

Transfer of Ultrafine Particles and Air in Multi-storey Buildings

An emerging issue in Denmark is passive smoking in residential buildings where non-smokers are exposed to smoke from their neighbours. There are various ways that smoke is transferred from one flat to another. The air transfer rate between two flats in a multi-storey building depends on its construction, tightness and age. This paper presents results of a study on the transfer of ultrafine particles and tracer gas in an older multi-storey building in Copenhagen. The aim of the study was to quantify the transfer ofultrafine particles and gases from one flat to another fiat before and after sealing the floor. A new floor-sealing method was applied to seal the floor between the two flats. The sealing method was developed by a firm specialising in sealing. Indoor ultrafine particle concentrations and tracer gas were measured continuously in the two fiats during the measuring periods. In the unoccupied fiat, the gas source was N20 and the particle source was burning cigarettes. Reduction of the concentration of ultrafine particles and tracer gas by sealing the floor with polyethylene and joint filler made of bitumen was studied. It was evaluated how the sealing performed with regard to decreasing the amount of ultrafine particles and a tracer gas transferred between two fiats separated by a floor. When the floor between the flats was not sealed, the results showed that about 4% of the ultraflne particles and 14% of the tracer gas were transferred. After sealing, the amount transferred was reduced to 1.6% and 5%, respectively.     

Crack detection of structures using modified extreme learning machine (MELM)

In this paper, crack detection and estimation method is presented in structures using modified extreme learning machine. For this purpose, extreme learning machine was modified using modified weights and biases. By using the first three frequencies and mode shapes as input, crack was detected as output. Performance of the proposed method was evaluated by using some numerical examples consisting of a simply supported beam, cantilever beam and fixed-simply supported beam. In addition, noise effect (3% noise level) on the measured frequencies and mode shapes have been investigated. In another work, a portal frame has been studied. The results indicated that the proposed method is effective and fast in crack detection and estimation of structures.