Upscaling A Challenge-Based And Modular Education Concept (CMODE-UP)

In 2019, a course at a Dutch University of Technology was redesigned towards challenge-based and modular education. The course was received positively by students and their learning outcomes (grades and engagement) increased compared to previous years. This redesign was quite intensive, and case-specific. It did not deliver a specific set of design principles that can easily be used to redesign other courses within the university or even other universities. Therefore, a follow-up project was started, that aims to deliver a framework to scale-up the course redesign tested in the previous study (CMODE; Challenge-based Modular On-demand Digital Education). This framework will be designed using practical principles and will be evidence-informed. The project consists of three stages: (1) informal interviews with key actors at our university, experienced in studying and/or designing modular instruction, a systematic literature review on challenge-based education and modular instruction; (2) a test of the design principles that were developed using the interviews and literature review; and (3) a test of the CMODE-up framework that was built on the results from the second stage, using think-out-loud protocols. In the current study we specifically focus on the first stage. A first look at the already existing literature around challenge-based education and modular instruction shows us that both concepts have been around for a long time in higher engineering education. Since education has become more and more digitized (and the development of MOOCs), it appears that the concepts have taken a quick increase in relevance. However, both concepts have only been studied minimally in relation to each other. We deem it thus highly relevant to first build a clear and proper view on both concepts, the strengths and weaknesses, and where both (can) meet. So that anyone who has intentions like ours - to implement both in higher education - can do this in an evidence-informed manner.</p

Experimental reconstruction of non-stationary sound and vibration sources by means of Transient Planar Near-field Acoustic Holography

A novel algorithm called Transient Planar Near-field Acoustic Holography is presented to analyse nonstationary sound and vibration sources. The method is able to obtain the time-dependent pressure, particle velocity and intensity field at the source plane without any pre-knowledge of the source by inverse propagation of measured pressure fields. This makes it possible to analyse phenomena like transients and run-ups for all kinds of vibrating and sound radiating objects. Transient responses of thin plates are analysed to experimentally validate the performance of the algorithm. The determined velocity at the center of the plate is validated using a laser vibro-meter directed at the center of the plate and the spatial fields are qualitatively compared with theoretical mode shapes. It is shown that the algorithm is able to analyse transient responses of plates with good quantitative as well as qualitative results.</p

The 2HWC HAWC Observatory Gamma Ray Catalog

We present the first catalog of TeV gamma-ray sources realized with the recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the most sensitive wide field-of-view TeV telescope currently in operation, with a 1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an instantaneous field of view >1.5 sr and >90% duty cycle, it continuously surveys and monitors the sky for gamma ray energies between hundreds GeV and tens of TeV. HAWC is located in Mexico at a latitude of 19 degree North and was completed in March 2015. Here, we present the 2HWC catalog, which is the result of the first source search realized with the complete HAWC detector. Realized with 507 days of data and represents the most sensitive TeV survey to date for such a large fraction of the sky. A total of 39 sources were detected, with an expected contamination of 0.5 due to background fluctuation. Out of these sources, 16 are more than one degree away from any previously reported TeV source. The source list, including the position measurement, spectrum measurement, and uncertainties, is reported. Seven of the detected sources may be associated with pulsar wind nebulae, two with supernova remnants, two with blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR