Investigating the impact of CAD simulations on student design thinking

Facilitating students to become informed designers is a goal in engineering education that has been proposed by multiple studies. The use of Computer-Aided Design (CAD) software has been used as a learning tool to promote design thinking in practical settings for undergraduate students. However, very little is known about the informed design process undertaken by these students while using the interactive and learning focused CAD tool to solve design challenges. This paper analyzes the nature of design thinking that happens when students use a particular CAD tool. In this study, I have adapted Crismond and Adams\u27 Informed Design Teaching and Learning Matrix (Crismond & Adams, 2012) to help identify qualities and patterns of informed design in the final artifacts of a class assignment using an educational CAD tool, Energy3D. It is hypothesized that a CAD software can help promote design thinking by allowing students to iterate and modify designs before submission thereby leading to increased informed design decisions and expert-like design practices. The major findings included that there was a significant increase between Reflection 1 and Reflection 2, in that there was evidence of more advanced design thinking evidence with students understanding the design challenge and building knowledge. However, there was no significant change in students weighing options and making decisions or reflection practices

Net Zero Energy House Evaluation

A net zero energy home was designed and built by Purdue University for the 2011 Solar Decathlon in Washington, DC. After earning a 2nd place finish in this international competition, the home was permanently located in Lafayette, IN and became a private residence.  Since that time, energy monitoring equipment has measured both energy consumption of the home and energy generation by the solar photovoltaic panels. Three full years of data (2013 to 2015) have been collected to show that the home has met its original design goal for net zero energy.  Beyond net zero, the data also shows interesting seasonal trends for HVAC, water heating, lighting, and other energy consuming devices. A survey of the current occupants provides further insight into how well features like indoor air quality, comfort, and aesthetics were incorporated into the overall design. The results suggest that a net zero energy home can be accomplished without sacrificing quality of life

Homogeneous bubble nucleation limit of mercury under the normal working conditions of the planned European Spallation Source

In spallation neutron sources, liquid mercury is the subject of big thermal and pressure shocks, upon adsorbing the proton beam. These changes can cause unstable bubbles in the liquid, which can damage the structural material. While there are methods to deal with the pressure shock, the local temperature shock cannot be avoided. In our paper we calculated the work of the critical cluster formation (i.e. for mercury micro-bubbles) together with the rate of their formation (nucleation rate). It is shown that the homogeneous nucleation rates are very low even after adsorbing several proton pulses, therefore the probability of temperature induced homogeneous bubble nucleation is negligible.Comment: 22 Pages, 11 figures, one of them is colour, we plan to publish it in Eur. Phys. J.

The Role of cavitation on Initiating Mercury-Steel Wetting

In accelerator-driven neutron sources such as the Spallation Neutron Source (SNS) with powers in the 2 MW range (time-averaged), the interaction of the energetic proton beam with the mercury target can lead to very high heating rates in the target. Although the resulting temperature rise is relatively small (a few degrees C), the rate of temperature rise is enormous (-10{sup 7} C/s) during the very brief beam pulse (-0.58 {micro}s). The resulting thermal-shock induced compression of the mercury leads to the production of large amplitude pressure waves in the mercury that interact with the walls of the mercury target and the bulk flow field. Understanding and predicting propagation of pressure pulses in the target are considered critical for establishing the feasibility of constructing and safely operating such devices. Safety-related operational concerns exist in two main areas, viz., (1) possible target enclosure failure from impact of thermal shocks on the wall due to its direct heating from the proton beam and the loads transferred from the mercury compression waves, and (2) impact of the compression-cum-rarefaction wave-induced effects such as cavitation bubble emanation and their impact on mercury-steel interfacial phenomena (such as wetting, mass transfer and erosion)

Thermal-Shock Assessments for National Spallation Neutron Source Target System

A perspective overview is provided on preliminary observations from simulations of thermal shock in the National Spallation Neutron Source (NSNS) at various power levels. Significant damage potential to structures may be present only at high ({approx}5-MW) power levels which may require inclusion of mitigative features. The simulation framework being utilized and under development is presented. Focused experiments are being conducted to derive key benchmarking data for the simulation framework as also for timely resolution of key design and operational-safety issues

Radiation Tailored Polymers for Detectors, Adhesive-Coatings and Other Industrial Uses

The ever growing importance of humans to depend on renewable resources has shifted the focus of consumers, producers, and even politicians to more sustainable answers. Furthermore, pressure on the oil and natural gas industry has elevated the status of biopolymers in this regard. Polylactic acid (PLA) is unique polymer that offers unique abilities for tailored property derivation; thereby, enabling one to replace many engineered polymers and provide a sustainable solution as a nontoxic renewable resource. As a bioplastic, the tailoring of PLA under various conditions is important to the application and integration into current industry uses. After irradiating high molecular weight PLA in increments of 10 kGy to 100 kGy, the molecule changes can be evaluated through viscometry and friability testing to optimize material properties. The change in molecular weight of irradiated samples was evaluated through dilute solution viscometry, and friability was evaluated based upon generation of fine particulates under fixed milling conditions. As the high molecular weight PLA was irradiated from 0 kGy to 100 kGy the relative viscosity (RV) decreased with increasing dose. The initial RV of 3.52 for 0 kGy conditions dropped to 1.62 after a dose of 100 kGy. The decrease in relative viscosity correlated directly with increasing friability and generation of fine powders. Such controlled tailoring of PLA should permit the user to derive a suitable formulation pertaining to its durability in different operational conditions. Food packaging and medical applications are the most likely industries to benefit from this approach

Comparison of Thermal and γ-photon Induced Degradation in Polylactic Acid for Potential as a Solid-State Radiation Detector

Degradation of the biopolymer Polylactic Acid, both thermally and through irradiation will cause physical changes in the material. These changes can be used in applications such as adhesives and sealants or in medical applications, but the primary focus of this study is for use as a solid-state radiation detector. A literature review shows that current research has been focused on thermal and γ-photon degradation in PLA but the physical characteristics such as melting temperature, latent heat of fusion, and composition of molecular bonds have not been compared in the same study. This study focuses on how thermal properties of PLA change in relation to the irradiation counterpart. The major findings of this study are that the melting temperature for thermally degraded samples decreased from 151.5 °C to 130.4 °C , but the melting temperature does not majorly vary with increasing doses up to 110 kGy. The composition of bonds in thermally degraded and irradiated samples experience a change due to the degradation. The latent heat of fusion for thermally degraded and irradiated samples decreases over time, or dose respectively. These characteristics can now be used to further investigate the use of PLA as a solid-state radiation detector, and provide alternative methods for processing PLA to specified physical characteristics

How Engineering Technology Students Perceive Mathematics

Engineering Technology (ET) is often combined with that of Engineering. Although Engineering Technology is based on a more hands-on approach and Engineering a theoretical approach, the two majors share a very similar pedagogy in teaching students the same engineering and scientific principles. An observation by an ET professor found that ET students more often than not would eschew the use of mathematical computations and instead provide answers they believe to be correct, without computation or explanation. Leading researchers to delve into possible reasons as to why ET students are reluctant to utilize mathematics. This study utilized in-person interviews with 15 undergraduate participants from a Midwestern University in the United States of America from ET to ascertain how ET students perceive mathematics. The results of the study found that although ET students were stated to not hate mathematics and are open to using mathematics, there was a slight apprehension towards math due to bad math experiences and not being able to connect the conceptual nature of mathematics to the visual and real-life scenarios ET students are used to facing. The results of this study help to lay the foundation for future research studies geared towards further understanding why ET students are apprehensive towards mathematics and ultimately how to help ET students overcome this apprehension