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Latent Heat Recovery Modification from Sodium Acetate Trihydrate due to Structural Changes Caused by Silver Nanoparticles
Get PDFPhase change materials (PCMs) have great potential as energy storage devices through the storage of thermal energy at low temperatures. Sodium acetate trihydrate (SAT) is a PCM commonly used for storing thermal energy for non-electric personal warmers, and releases that energy as latent heat during the phase transition from a supersaturated liquid state to a solid, crystal state at room temperature. SAT is an inexpensive, non-toxic PCM. These characteristics make SAT ideal for the development of reusable, non-electric neonatal blankets. This application requires careful optimization of the maximum temperature attained by the SAT solution, balanced by a prolonged heat release that will last hours. It is hypothesized that latent heat release will be prolonged if crystal growth rate is slowed via the interference of additives with the crystallization process. In this work we investigate the effects of adding nanoparticles to a solution of SAT and water. We find that the nanoparticles expedite the crystal growth, but that the growth rate of SAT crystals is non-monotonic with increasing nanoparticle concentration. Powder X-ray diffraction data indicate that the crystal structure is not affected with larger size particles are added, but strongly modified with the addition of 10nm size silver nanoparticles
Use of Technology and Software in the Classroom - Active Learning and Projectbased Learning
No full textThe work presented in this paper is in continuation of an earlier paper presented at the ASEE2014 NCS Conference held at Oakland University, MI [1] in which analysis of a tile winding machine structure was considered. Math and CAE tools were used for this purpose. The main purpose of this work is to analyze the structure of the same machine to understand the factors contributing to the large deflection of the shaft during operation and to propose a new design. Using the active learning tools mainly in the form of discussions and questions and answers (Q&A) and project based learning, this real life application was assigned as a final project to one of the students group of finite element analysis (elective) course that the second author taught. The students are to analyze the cause of the problem, discuss it using the Q&A sessions and then to look for a solution to redesign the structure. Since cost is also important, they have to propose a low cost device although detailed cost analysis was not required. Some (trial and error) optimization was expected to be carried out. One-dimensional beam and frame models were used and the solution by direct stiffness method is carried out by MatLab, and NX CAE tools. Finally, preliminary calculations were done by mechanics approach using EXCEL. From an observation of the results, a design change of both the function and size of the structural elements is attempted. The learning experience of assigning this real life application as a final project to the senior undergraduate and graduate students is discussed briefly
Reverse Oblique End Screws in Nonlocking Plates Decrease Construct Strength in Synthetic Osteoporotic Bone Medium
No full textFracture stability can be challenging for osteoporotic individuals. The end screw of nonlocked plates is subjected to the greatest loading and is typically the site of construct failure. To enhance fixation, the end screw can be angled away from the fracture. The current study biomechanically evaluated screws angled the other direction: toward the fracture using 3.5-mm dynamic compression plates in an osteoporotic bone model. Three different plate lengths (6-, 8-, 12-hole) were tested in three-point bending with an oblique, perpendicular, or reverse oblique end screw. The peak load for loss of screw fixation for the reverse oblique end screw constructs was significantly less than the other screw orientations for all plate lengths. The 12-hole peak load, energy, and displacement magnitudes for all three screw orientations were significantly greater than all 6- and 8-hole constructs. The use of a reverse oblique end screw is inferior to both perpendicular and oblique end screws
A Novel Multimode Hybrid Energy Storage System and its Energy Management Strategy for Electric Vehicles
No full textThis paper proposes a novel topology of multimode hybrid energy storage system (HESS) and its energy management strategy for electric vehicles (EVs). Compared to the conventional HESS, the proposed multimode HESS has more operating modes and thus it could in further enhance the efficiency of the system. The rule-based control strategy and the power-balancing strategy are developed for the energy management strategy to realize mode selection and power distribution. Generally, the DC–DC converter will operate at peak efficiency to convey the energy from the batteries to the UCs. Otherwise, the pure battery mode or the pure ultracapacitors (UCs) mode will be utilized without the DC–DC converter. To extend the battery life, the UCs have the highest priority to recycle the energy and the batteries are isolated from being recharged directly during regenerative braking. Simulations and experiments are established to validate the proposed multimode HESS and its energy management strategy. The results reveal that the energy losses in the DC–DC converter, the total energy consumption and the overall system efficiency of the proposed multimode HESS are improved compared to the conventional HESS
Modeling, Control, and Optimization Technologies in Electric Drive Vehicles
Get PDFTo address the two urgent issues nowadays of protecting the environment and achieving energy sustainability, it is of strategic importance on a global scale to replace oil-dependent vehicles with electric drive vehicles (EDVs). Numerical simulation and optimization are essential to simulate the actual hardware and minimize the development procedure and cost. Accurate and efficient modeling, control, and optimization technologies have been the indispensable tools. EDVs have been continuously improved owing to the advancement of systematic control and power management, energy systems, batteries, and pack technologies, as well as economic and policy incentives, public awareness of energy sustainability/affordability, and environmental concerns. The primary goal of this special section is to provide timely solutions to technological and economic challenges in modeling, simulation, control, and optimization of EDVs. The accepted papers cover a range of different aspects of modeling, control, and optimization technologies for electric vehicles
