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.     

The thermal effect on vibration of zigzag single walled carbon nanotubes using nonlocal Timoshenko beam theory

Based on nonlocal theory of thermal elasticity mechanics, a nonlocal elastic Timoshenko beam model is developed for free vibration analysis of zigzag single-walled carbon nanotube (SWCNT) considering thermal effect. The nonlocal constitutive equations of Eringen are used in the formulations. The equivalent Young’s modulus and shear modulus for zigzag SWCNT are derived using an energy-equivalent model. Results indicate significant dependence of natural frequencies on the temperature change as well as the chirality of zigzag carbon nanotube. These findings are important in mechanical design considerations of devices that use carbon nanotubes.     

Adaptive Sliding Mode Observer for Nonlinear Interconnected Systems with Time Varying Parameters

In this paper, a class of nonlinear interconnected systems with uncertain time varying parameters (TVPs) is considered. Both the interconnections and the isolated subsystems are nonlinear. Sliding mode control method and adaptive techniques are employed together to design an observer to estimate the state variables of the systems in presence of unknown TVPs. The Lyapunov direct method is used to analysis the stability of the sliding motion and it is not required to solve the so‐called constrained Lyapunov problem (CLP). A set of conditions is developed under which the augmented systems formed by the error dynamical systems and the designed adaptive laws, are globally uniformly ultimately bounded. A simulation example is presented and the results show that the method proposed in this paper is effective.     

Dealing with feature interactions for prismatic parts in STEP-NC

Determining the precedence of machining features is a critical issue in feature-based process planning. It becomes more complex when geometric interaction occurs between machining features. STEP-NC, the extension of STEP (ISO 10303) standard developed for CNC controllers, is a feature-based data model. It represents all the geometric and topological product data minus feature interactions. In this paper, machining precedence of interactive and non-interactive STEP-NC features is discussed. Local and global precedence of machining features are defined on the basis of geometric constraints, such as geometric interaction of features and feature approach face and technological constraint such as access direction of the cutting tool. A software tool has been developed to visualize the STEP-NC part model and to generate the graphs of feature interaction and feature precedence. The output can be then used to augment the STEP-NC data in order to generate the optimal sequence of operations.     

Machining precedence of 2½D interacting features in a feature-based data model

In process planning, determining feature’s machining precedence is an essential step. The task becomes more difficult if features interact with each other, in which case the feature precedence information may suggest multiple machining sequences of the features. This paper considers interacting features in a feature-based model for process planning tasks. For each feature, precedence information is generated considering both roughing and finishing operations. A rule-based system is developed and implemented based on the information about machining precedence of the interacting features. The STEP-NC data model is used as the underlying data model. This model is object-oriented and compliant with the existing STEP standards. The output of the system is also in the STEP format through an information model developed using the EXPRESS language.     

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.     

Photovoltaic enhancement of nanostructured boron-doped rutile phase TiO2 nanorods via facile hydrothermal method

Journal of Materials Science: Materials in Electronics - Several doping processes are being investigated for the enhancement and efficient utilization of TiO2 properties with increased focus on the...     

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.     

Gamma Radiation-induced Graft Copolymerization of – Phenylmaleimide onto Polypropylene Films

Polypropylene (PP) films were grafted with N-phenylmaleimide using γ-radiation. The effect of both monomer concentration and dose rate on the degree of grafting was measured. Characterization of the grafted PP films included IR spectroscopy, X-ray spectroscopy, electrical conductivity, mechanical properties and thermal stability has been studied. © of SCI.     

Electrical and mechanical properties of grafted and ungrafted polyacrylamide–rubber blends

A systematic dielectric and mechanical study was carried out on an ethylene propylene diene monomer (EPDM) and a nitrile rubber (NBR) blended with polyacrylamide (PAM). From the compatibility investigations, it was found that EPDM/PAM is incompatible while NBR/PAM is semicompatible. To overcome the problem of phase separation between rubber and PAM, PAM was grafted with two different monomers, acrylonitrile (AN) and acrylic acid (AA), and added with 10 phr to both EPDM and NBR. Poly(vinyl chloride) (PVC) was also added as a compatiblizing agent to both types of blend. It was concluded that the addition of either a grafted polymer or PVC to the rubber–plastic blend could improve to some extent the compatibility of such blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2053–2059, 1998