An efficient evolutionary optimization algorithm for multiobjective distribution feeder reconfiguration

In this paper, a Multi-objective Modified Honey Bee Mating Optimization (MMHBMO) evolutionary algorithm is proposed to solve the multi-objective Distribution Feeder Reconfiguration (DFR). The real power loss, the number of the switching operations and the deviation of the voltage at each node are considered as the objective functions. Conventional algorithms for solving the multiobjective optimization problems convert the multiple objectives into a single objective using a vector of the user-predefined weights. This paper presents a new MHBMO algorithm for the DFR problem. In the proposed algorithm an external repository is utilized to save non-dominated solutions found during the search process. A fuzzy clustering technique is used to control the size of the repository within the limits because of the objective functions are not the same. The proposed algorithm is tested on a distribution test feeder.     

Fault management in wireless sensor networks

Wireless sensor networks (WSNs) have gradually emerged as one of the key growth areas for pervasive computing in the twenty-first century. Recent advances in WSN technologies have made possible the development of new wireless monitoring and environmental control applications. However, the nature of these applications and harsh environments also created significant challenges for sensor networks to maintain a high quality of service in potentially harsh environments. Therefore, efficient fault management and robust management architectures have become essential for WSNs. In this article, we address these challenges by surveying existing fault management approaches for WSNs. We divide the fault management process into three phases: fault detection, diagnosis, and recovery and classify existing approaches according to these phases. Finally, we outline future challenges for fault management in WSNs.     

Experimental optimization of composite collapsible tubular energy absorber device

A four-phase program to improve the specific energy absorbed by axially crushed composite collapsible tubular energy absorber devices was undertaken. In the first phase, examining of the crushing behaviour of non-triggered tubes was carried out. The second phase is aimed at obtaining the best position for the triggered wall. The third phase focuses on the effects of material sizing in order to understand the influence of triggered wall length on the responses of composite circular tubes to the axial crushing load. The results of these three phases of the study contribute to the fourth whose objective is to optimize the shape geometry of the cross-section area to further improving in tube energy absorption capability. The experimental results demonstrated the strong potential benefits of optimizing the material distribution. The sizing and shape optimization of composite collapsible tubes exhibited a pronounced effect on their capability to absorb high specific energy under axial compressive load.     

A new composite energy absorbing system for aircraft and helicopter

In this paper, an innovative lightweight composite energy-absorbing keel beam system has been developed to be retrofitted in aircraft and helicopter in order to improve their crashworthiness performance. The developed system consists of everting stringer and keel beam. The sub-floor stringers were designed as everting stringer to guide and control the failure mechanisms at pre-crush and post-crush failure stages of composite keel beam webs and core. Polyurethane foam was employed to fill the core of the beam to eliminate any hypothesis of global buckling. Quasi-static axial crushing behaviour of the composite keel beam is investigated experimentally. The results showed that the crushing behaviour of the developed system is found to be sensitive to the change in keel beam web thickness. Laminate sequence has a significant influence on the failure mode types, average crush loads and energy absorption capability of composite keel beam. The desired energy absorbing mechanism revealed that the innovated system can be used for aircraft and helicopter and meet the requirements, together with substantial weight saving.     

Floating ring journal bearings: theory, design and optimization

The performance characteristics and design data for journal bearings with a precise floating ring inserted between the rotating journal and a rigid housing are investigated theoretically. Based on convenient boundary conditions, a theory has been developed to predict the floating ring behaviour. Performance charts are presented with curves provided with optimum design areas to help in practical design applications. Induced ring speed, hydrodynamic behaviour, oil film variation, load capacity and frictional drag could thus be analytically or graphically determined. Results indicate that the ring dimensions are a dominant factor in deciding the final bearing behaviour and that the oil film thickness between the ring and the housing is much thinner than that between the journal and the ring. The floating ring bearing showed less frictional power loss than a fixed sleeve bearing, but this may have been achieved at the expense of the load capacity.     

The effect of hardness on the frictional behaviour of metals

It is shown experimentally that hard metals have lower frictional resistance than softer metals owing to stronger interatomic linking bonds. In hard metals the atomic bonds are strong and hence the resistance to adhesion is increased, providing low frictional characteristics. Surfaces hardened by heat treatment are also characterized by low friction. This is explained by metallurgical changes leading to changes in the structure by phase transformation, increase in the surface energy and the induction of internal (residual) stresses.     

Educational Architecture-Oriented Software Linking Conceptual Design and Solar Intensity

Fundamental architectural decisions such as a building’s form and orientation greatly influence the energy performance of a building. As these decisions are taken very early in the design process, it is important for the designer to consider such performance when comparing design alternatives. Unfortunately, this is rarely done by architects. The reason can be easily tracked to the way most architects learn about energy. Simple charts and some rules of thumb are preferred over complex calculations used by engineers and energy specialists. This paper presents an experiment conducted by the writer to tackle this problem. The writer used a purpose-made software program that is developed to help architecture students learn the impact of the conceptual design decisions on the expected energy performance of a building represented in the solar intensity on the building surfaces. The paper describes the capabilities and the structure of the software program as well as the context and the results of the experiment.     

Rapidly reconfigurable optical phase encoder-decoders based on fiber Bragg gratings

We demonstrate the capacity for fast dynamic reconfiguration of optical code-division multiple access (OCDMA) phase en/decoders based on fiber Bragg gratings and a thermal phase-tuning technique. The tuning time between two different phase codes is measured to be less than 2 s. An OCDMA system using tunable-phase decoders is compared with a system using fixed-phase decoders and, although the system using fixed-phase decoders exhibits a shorter output autocorrelation pulsewidth and lower sidelobes, the system using tunable-phase decoders has advantages of flexibility and a more relaxed requirement on the input pulsewidth.     

Retracted: Hydrogen production using catalytic and noncatalytic supercritical water gasification of bagasse

The above article, published online on 10 May 2014 in Wiley Online Library ( wileyonlinelibrary.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Ibrahim Dincer, and John Wiley & Sons, Ltd. The retraction has been agreed due to overlap between this article and the following article published in Fuel Processing Technology; ‘Hydrogen production via supercritical water gasification of bagasse using unpromoted and zinc promoted Ru/γ‐Al2O3 nanocatalysts’ by Mokhtar Babatabar, Ahmad Tavasoli, Ajay K. Dalai, Umashanker Das. Volume 123, 2014, pages 140–148.     

Dehydration of potato slices following brief dipping in osmotic solutions: Effect of conditions and understanding the mechanism of water loss

A novel variant of osmotic dehydration, named here as postdipping dehydration—where a material is dipped in a salt or sugar solution for a very short time followed by simple exposure to ambient conditions was explored with the aim of lowering water content of potato slices but at the same time not gain a high level of sugar/salt. The rate of water loss, which was rapid initially, was found to approach equilibrium. This article also explored whether the water loss process could subsequently be kick started once again, by employing a multistage process, where each stage consisted of osmotic solution dipping followed by ambient holding of the potato slices that had reached equilibrium in the earlier stage. Water loss values comparable to conventional osmotic dehydration could be achieved thus, but with significantly lower overall solid gain (<50%)—which can potentially yield a significantly healthy product option.