Numerical simulation of the sedimentation of an elliptic particle under external electric field using ISPH

Incompressible smoothed particle hydrodynamics method has been used to simulate the sedimentation of a two-dimensional rigid elliptic disc in quiescent medium in presence of an external electric field. The motion of the elliptic disc in the absence of the electric field is compared to literature data and good agreement is observed. The results show that the trajectory of the elliptic disc in presence of the electric field is strongly affected by the electrical properties of fluid and solid

Multi-material topology optimization of structures using peridynamics

This study presents a multi-material topology optimization based on Peridynamics (PD). The conventional topology optimization mainly used a mesh-based numerical method, i.e., Finite Element (FE) method. Moving boundaries, large deformations, and cracks/damages are some limitations of the mesh-based numerical method. In this study, PD as a meshless method is proposed to employ in the topology optimization to remove limitations of the mesh-based topology optimization. The minimization of compliance, i.e., strain energy, is chosen as the objective function subjected to the volume constraint. The design variables are the relative density of the candidate materials defined at particles employing gradient based optimization approach. A filtering scheme is also adopted to avoid the checkerboard issue and maintain the optimization stability. The proposed approach is an alternative and powerful tool for multiple additive manufacturing in finding multi material optimal topologies of the structures with embedded crack

A study of the Space Station Freedom response to the disturbance environment

A relatively general formulation for studying the dynamics and control of an arbitrary spacecraft with interconnected flexible bodies has been developed. This self-contained and comprehensive numerical algorithm using system modes is applicable to a large class of spacecraft configurations of contemporary and future interest. Here, versatility of the approach is demonstrated through the dynamics and control studies aimed at the evolving Space Station Freedom

An Evaluation of the QTI E-Learning Standard in Resource-Limited Environments

Early Learning Management Systems (LMSes) were often criticised for their lack of interoperability. This situation is now being addressed by a cohesive standardisation effort in the form of IEEE-LOM, IMS-QTI and related specifications. While these standards are now supported by numerous LMSes, it is not known if they can be broadly applied to different types of LMSes developed for different communities, with widely varying facilities and requirements. This question was the focus of this study, where the IMS Question and Test Interoperability (QTI) standard was investigated for its applicability in a learning environment where not all learners have access to computers. It was proposed that alternative electronic learning management systems could focus on the teacher, with a shift in learning medium (to paper) at the interface between educators and students. To test this new philosophy for building LMSes, the QTI standard was used as the basis for a Web-based application to design questions and compose tests. Individual questions, collections of questions and entire tests were stored as linked and threaded collections of IMS-encoded records. The system then provided the ability to render a collection of questions for printing to paper. Analysis of the system building process revealed that the QTI standard is ambiguous and not easily applied in non-traditional situations where the focus is not on online testing. In spite of this shortcoming, a formal evaluation using a sample of educators confirmed that the system's use of the QTI standard was virtually transparent and that the system was indeed usable

Bovine Feed Manipulation, Enhancement of Conjugated Linoleic Acid and Its Bioavailability

Diet is a pivotal contributing factor to the onset and progression of some chronic ailments nowadays. The conjugated linoleic acid (CLA), a bioactive component of ruminant fat, introduces more elucidates what we know polyunsaturated fats and diseases. CLA, a mixture of isomers c9, t11 and t10, c12, is the most abundant ranging from 80 to 90% of total CLA isomers and account for most known health benefits. Dairy milk and meat are the major dietary sources of CLA, and its concentration is of great interest to human health. The biofunctionalities of CLA from enriched dairy products are major attributes in the context of a substance present in our everyday diet. Thus, dietary modifications in animal feed, synthetic and microbial production have been made to increase CLA intake to enhance its clinical manifestations. However, the bioavailability and distribution of enriched or supplemented CLA has not been fully elucidated because of its response variation in different animal models. This chapter deals with different dietary sources, availability, enhancement of CLA in dairy products and its positive manifestation against different maladies. In conclusion, it is feasible to produce CLA-enriched dairy products with acceptable storage and sensory characteristics while deriving its nutritional benefits

Evaluation Of Energy Efficient Propulsion Technologies For Unmanned Aerial Vehicles

The transition to cleaner, more efficient and longer-endurance aircraft is at the forefront of current research and development in air transportation systems. The focus of this research is to experimentally evaluate Hybrid Propulsion and Energy Harvesting Systems in Unmanned Aerial Vehicles (UAV). Hybrid systems offer several potential benefits over more conventional gasoline and electric systems including lower environmental impacts, reduced fuel consumption, longer endurance, redundancy and distributed propulsion. Additional energy efficiency can be achieved by harvesting some of the thermal energy of the exhaust gases. By using the Seebeck effect, the temperature gradient between ambient air and the exhaust can be used to generate electric power, making it possible to eliminate costly mechanical systems such as alternators and reduce fuel consumption. The development and experimental evaluation of a hybrid-propulsion UAV was carried out at the University of Victoria Center for Aerospace Research (UVIC-CfAR) in the framework of the Green Aviation Research & Development Network (GARDN) grant. The work involved the development of a framework to evaluate UAV hybrid propulsion efficiency, as well as to predict the amount of power harvestable from thermoelectric generators (TEG). The hybrid propulsion framework was used to investigate the trade-offs between different hybrid architectures against conventional electric and internal combustion propulsion systems. The energy harvesting module was designed to evaluate the trade-off between energy harvested, implementation costs and weight. In order to validate the computational results, experimental testing was performed. First, an apparatus was designed to collect performance data of a triple-TEG system connected to a 4-stroke Saito internal combustion engine. Thermal performance of the system was evaluated at eleven different test points, and a number of variables were modified to simulate real flight profiles. Next, another apparatus was designed to characterize the performance of a parallel hybrid-electric propulsion system in a UAV. This apparatus allows for different mission profiles that closely match the flight test data from other propulsion types

Topology optimization of cracked structures using peridynamics

Finite element method (FEM) is commonly used with topology optimization algorithms to determine optimum topology of load bearing structures. However, it may possess various difficulties and limitations for handling the problems with moving boundaries, large deformations, and cracks/damages. To remove limitations of the mesh-based topology optimization, this study presents a robust and accurate approach based on the innovative coupling of Peridynamics (PD) (a meshless method) and topology optimization (TO), abbreviated as PD-TO. The minimization of compliance, i.e., strain energy, is chosen as the objective function subjected to the volume constraint. The design variable is the relative density defined at each particle employing bi-directional evolutionary optimization approach. A filtering scheme is also adopted to avoid the checkerboard issue and maintain the optimization stability. To present the capability, efficiency and accuracy of the PD-TO approach, various challenging optimization problems with and without defects (cracks) are solved under different boundary conditions. The results are extensively compared and validated with those obtained by element free Galerkin method and FEM. The main advantage of the PD-TO methodology is its ability to handle topology optimization problems of cracked structures without requiring complex treatments for mesh connectivity. Hence, it can be an alternative and powerful tool in finding optimal topologies that can circumvent crack propagation and growth in two and three dimensional structures

Monitoring the damage state of fiber reinforced composites using an FBG network for failure prediction

A structural health monitoring (SHM) study of biaxial glass fibre-reinforced epoxy matrix composites under a constant, high strain uniaxial fatigue loading is performed using fibre Bragg grating (FBG) optical sensors embedded in composites at various locations to monitor the evolution of local strains, thereby understanding the damage mechanisms. Concurrently, the temperature changes of the samples during the fatigue test have also been monitored at the same locations. Close to fracture, significant variations in local temperatures and strains are observed, and it is shown that the variations in temperature and strain can be used to predict imminent fracture. It is noted that the latter information cannot be obtained using external strain gages, which underlines the importance of the tracking of local strains internally