Dynamic whole system testing of combined renewable heating systems : the current state of the art

Objective: For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods. Methods: New dynamic whole system test methods were developed based on “hardware in the loop” concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps. Results: All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components. Conclusion: Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories. Practice implications: A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests.

Multimodal Literacy as a form of Communication : What is the state of the students at Dalarna University multimodal literacy?

Literacy is an invaluable asset to have, and has allowed for communication, documentation and the spreading of ideas since the beginning of the written language. With technological advancements, and new possibilities to communicate, it is important to question the degree to which people’s abilities to utilise these new methods have developed in relation to these emerging technologies. The purpose of this bachelor’s thesis is to analyse the state of students’ at Dalarna University mulitimodal literacy, as well as their experience of multimodality in their education. This has led to the two main research questions: What is the state of the students at Dalarna University multimodal literacy? And: How have the students at Dalarna University experienced multimodality in education? The paper is based on a mixed-method study that incorporates both a quantitative and qualitative aspect to it. The main thrust of the research paper is, however, based on a quantitative study that was conducted online and emailed to students via their program coordinators. The scope of the research is in audio-visual modes, i.e. audio, video and images, while textual literacy is presumed and serves as an inspiration to the study. The purpose of the study is to analyse the state of the students’ multimodal literacy and their experience of multimodality in education. The study revealed that the students at Dalarna University have most skill in image editing, while not being very literate in audio or video editing. The students seem to have had mediocre experience creating meaning through multimodality both in private use and in their respective educational institutions. The study also reveals that students prefer learning by means of video (rather than text or audio), yet are not able to create meaning (communicate) through it.

Thomas-Fermi ground state of dipolar fermions in a circular storage ring

Recent developments in the field of ultracold gases has led to the production of degenerate samples of polar molecules. These have large static electric-dipole moments, which in turn causes the molecules to interact strongly. We investigate the interaction of polar particles in waveguide geometries subject to an applied polarizing field. For circular waveguides, tilting the direction of the polarizing field creates a periodic inhomogeneity of the interparticle interaction. We explore the consequences of geometry and interaction for stability of the ground state within the Thomas-Fermi model. Certain combinations of tilt angles and interaction strengths are found to preclude the existence of a stable Thomas-Fermi ground state. The system is shown to exhibit different behavior for quasi-one-dimensional and three-dimensional trapping geometries.