The use of computer-based programming environments as computer modelling tools in early science education: the cases of textual and graphical program languages

This is an interpretive case study seeking to develop detailed and comparative descriptions of how two groups of fifth grade students used two different Computer-Based Programming Environments (CPEs) (namely Microworlds Logo and Stagecast Creator) during scientific modelling. The primary sources of data that were used in this four-month-long study include videotaped students' group work and whole-class discussions, and the instructors’ reflective journals. For the data analysis contextual inquiry was used in conjunction with analysis of student conversation in order to gain better insight in students’ activity and conversation patterns while working with CPEs. Findings highlight the differences in the ways that the students used the two CPEs in the context of developing models of natural phenomena with respect to three distinct phases that emerged from data analysis that include student approaches to (i) planning, (ii) writing and debugging code and (iii) using code to represent the phenomenon under study. Lastly, findings highlight which aspects of students work during the three phases can be productive for scientific modelling, proposing possible relationships between student work and CPE features

CASE STUDIES OF FIFTH-GRADE STUDENT MODELING IN SCIENCE THROUGH PROGRAMMING: COMPARISON OF MODELING PRACTICES AND CONVERSATIONS

This is a descriptive case study investigating the use of two computer-based programming environments (CPEs), MicroWorldsTM (MW) and Stagecast CreatorTM (SC), as modeling tools for collaborative fifth grade science learning. In this study I investigated how CPEs might support fifth grade student work and inquiry in science. There is a longstanding awareness of the need to help students learn about models and modeling in science, and CPEs are promising tools for this. A computer program can be a model of a physical system, and modeling through programming may make the process more tangible: Programming involves making decisions and assumptions; the code is used to express ideas; running the program shows the implications of those ideas. In this study I have analyzed and compared students' activities and conversations in two after-school clubs, one working with MW and the other with SC. The findings confirm the promise of CPEs as tools for teaching practices of modeling and science, and they suggest advantages and disadvantages to that purpose of particular aspects of CPE designs. MW is an open-ended, textual CPE that uses procedural programming. MW students focused on breaking down phenomena into small programmable pieces, which is useful for scientific modeling. Developing their programs, the students focused on writing, testing and debugging code, which are also useful for scientific modeling. SC is a non-linear, object-oriented CPE that uses visual program language. SC students saw their work as creating games. They were focused on the overall story which they then translated it into SC rules, which was in conflict with SC's object-oriented interface. However, telling the story of individual causal agents was useful for scientific modeling. Programming in SC was easier, whereas reading code in MW was more tangible. The latter helped MW students to use the code as the representation of the phenomenon rather than merely as a tool for creating a simulation. The analyses also pointed to three emerging "frames" that describe student's work focus, based on their goals, strategies, and criteria for success. Emerging "frames" are the programming, the visualization, and the modeling frame. One way to understand the respective advantages and disadvantages of the two CPEs is with respect to which frames they engendered in students

Analysis and design of a silicide-tetrahedrite thermoelectric generator concept suitable for large-scale industrial waste heat recovery

Industrial Waste Heat Recovery (IWHR) is one of the areas with strong potential for energy efficiency and emissions reductions in industry. Thermoelectric (TE) generators (TEGs) are among the few technologies that are intrinsically modular and can convert heat directly into electricity without moving parts, so they are nearly maintenance-free and can work unattended for long periods of time. However, most existing TEGs are only suitable for small-scale niche applications because they typically display a cost per unit power and a conversion efficiency that is not competitive with competing technologies, and they also tend to rely on rare and/or toxic materials. Moreover, their geometric configuration, manufacturing methods and heat exchangers are often not suitable for large-scale applications. The present analysis aims to tackle several of these challenges. A module incorporating constructive solutions suitable for upscaling, namely, using larger than usual TE elements (up to 24 mm in diameter) made from affordable p-tetrahedrite and n-magnesium silicide materials, was assessed with a multiphysics tool for conditions typical of IWHR. Geometric configurations optimized for efficiency, power per pair and power density, as well as an efficiency/power balanced solution, were extracted from these simulations. A balanced solution provided 0.62 kWe/m2 with a 3.9% efficiency. Good prospects for large-scale IWHR with TEGs are anticipated if these figures could be replicated in a real-world application and implemented with constructive solutions suitable for large-scale systems.Fundação para a Ciência e a Tecnologia, European Regional Development Fund (ERDF), P.O.F.C.—COMPETE, European and National Funds: M-ERA.net Project THERMOSS (M-ERANET2/0011/2016), MEtRICs—Mechanical Engineering and Resource Sustainability Centre (UIDB/ 04077/2020), C2TN—Center for Nuclear Sciences and Technologies (UID/Multi/04349/2019), Project Exhaust2Energy (PTDC/EMS-ENE/3009/2014)

Energy harvesting technologies for structural health monitoring of airplane components - a review

With the aim of increasing the efficiency of maintenance and fuel usage in airplanes, structural health monitoring (SHM) of critical composite structures is increasingly expected and required. The optimized usage of this concept is subject of intensive work in the framework of the EU COST Action CA18203 "Optimising Design for Inspection" (ODIN). In this context, a thorough review of a broad range of energy harvesting (EH) technologies to be potentially used as power sources for the acoustic emission and guided wave propagation sensors of the considered SHM systems, as well as for the respective data elaboration and wireless communication modules, is provided in this work. EH devices based on the usage of kinetic energy, thermal gradients, solar radiation, airflow, and other viable energy sources, proposed so far in the literature, are thus described with a critical review of the respective specific power levels, of their potential placement on airplanes, as well as the consequently necessary power management architectures. The guidelines provided for the selection of the most appropriate EH and power management technologies create the preconditions to develop a new class of autonomous sensor nodes for the in-process, non-destructive SHM of airplane components.The work of S. Zelenika, P. Gljušcic, E. Kamenar and Ž. Vrcan is partly enabled by using the equipment funded via the EU European Regional Development Fund (ERDF) project no. RC.2.2.06-0001: “Research Infrastructure for Campus-based Laboratories at the University of Rijeka (RISK)” and partly supported by the University of Rijeka, Croatia, project uniri-tehnic-18-32 „Advanced mechatronics devices for smart technological solutions“. Z. Hadas, P. Tofel and O. Ševecek acknowledge the support provided via the Czech Science Foundation project GA19-17457S „Manufacturing and analysis of flexible piezoelectric layers for smart engineering”. J. Hlinka, F. Ksica and O. Rubes gratefully acknowledge the financial support provided by the ESIF, EU Operational Programme Research, Development and Education within the research project Center of Advanced Aerospace Technology (Reg. No.: CZ.02.1.01/0.0/0.0/16_019/0000826) at the Faculty of Mechanical Engineering, Brno University of Technology. V. Pakrashi would like to acknowledge UCD Energy Institute, Marine and Renewable Energy Ireland (MaREI) centre Ireland, Strengthening Infrastructure Risk Assessment in the Atlantic Area (SIRMA) Grant No. EAPA\826/2018, EU INTERREG Atlantic Area and Aquaculture Operations with Reliable Flexible Shielding Technologies for Prevention of Infestation in Offshore and Coastal Areas (FLEXAQUA), MarTera Era-Net cofund PBA/BIO/18/02 projects. The work of J.P.B. Silva is partially supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020. M. Mrlik gratefully acknowledges the support of the Ministry of Education, Youth and Sports of the Czech Republic-DKRVO (RP/CPS/2020/003

An energy-based model reduction methodology for automated modeling.

Commercial competition demands a reduction in the development time of new products. While it has been recognized for a number of years that the development process can be accelerated with the use of computer simulation based on mathematical models of the product, the lack of appropriate modeling tools has limited the effectiveness of this approach. It is the premise of this work that a new modeling metric able to handle nonlinear dynamic systems and all types of energy elements, will improve the effectiveness of modeling tools. A new modeling metric, activity, which is based on energy, is developed in this work. This metric is used to rank the importance of all energy elements in a system. The ranking of the energy elements provides the relative importance of the model parameters and this information can be used to reduce the size of the model. The metric is implemented in an algorithm called Model Order Reduction Algorithm (MORA). MORA is applied to a nonlinear quarter car model showing that elements with low activity can be eliminated without any significant change in model accuracy. MORA is also applied to linear systems, where the steady state activity to sinusoidal inputs is considered. It is shown that the activity varies with frequency, and thus, a series of reduced models can be generated as a function of the excitation frequency. For multibody systems, the activity metric can be applied to each DOF of the rigid bodies. The activity metric is applied to a heavy-duty tractor-semitrailer to demonstrate that a significant number of the model parameters are insignificant, and therefore, that a substantial reduction in the model size can be achieved. Finally, an interpretation algorithm based on the activity metric is developed to provide the user with physical meaning of each low activity element eliminated. In addition, the use of the activity metric to rank the energy elements augments the insight into the model, since the engineer can focus on a smaller number of elements that are identified by MORA as important to the system behavior. In conclusion, this work develops an automated modeling algorithm, MORA, which can be used to rank model parameter importance, reduce model complexity and help provide physical insight into a system. MORA extends the applicability of automated modeling to systems that can be represented by nonlinear dynamic models and it should improve the use of modeling and simulation for product development.Ph.D.Applied SciencesComputer scienceMechanical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131482/2/9909941.pd