169 research outputs found
Open Educational Resources:Basic concepts, challenges, and business models
Besides research, education is the raison d’être of each university. Education can help close equity gaps and maintain social cohesion between and within countries. In this context, the digitisation era offers new opportunities, for example, in the form of distance and online learning. However, innovations can also come with challenges, such as employed and unemployed people requiring to adapt to a progressing working environment at ever shorter intervals (life-long learning). Consequently, it is increasingly important to gain free access to up-to-date educational materials about a wide range of subjects and at multiple academic levels.
In this document, we introduce the concept of Open Educational Resources (OER). We start with establishing a definition of OER, what is needed to call educational materials OER, and the differences in comparison to related concepts, such as Massive open online courses. We then address the question of who can benefit from OER. It reports on the incentives to publish OER taking into account the perspectives of the involved stakeholders, i.e., the general public, universities and lecturers, and students. Afterwards, we pay attention to the challenges that come with OER. Subsequently, we provide a list of potential business models around OER, their underlying concepts, benefits, limitations, and projects making use of them. We also consider the paradox that OER are not intended to generate revenue but that ignoring income can make OER unsustainable. The document concludes by outlining possible steps to realize OER (e.g., organizing a round table to initiate a discussion about how to realise OER at the faculty level)
Wear of polycrystalline boron nitride tool during the friction stir welding of steel
The wear issue of a polycrystalline boron nitride (PCBN) tools during the friction stir welding of two grades of steel, DH36 and EH46, was studied. Two welding traverse and tool rotational speeds were used when welding the DH36 steel. A low tool speed (200RPM, 100 mm/min) and a high tool speed (550RPM, 400 mm/min) were denoted by W1D and W2D, respectively. Nine welding conditions were applied to the welding of EH46 steel plate including seven plunge/dwell trials (W1E–W7E) and two steady-state trials (W8E and W9E). SEM–EDS and XRD tests were applied in order to reveal the boronitride (BN) particles inside the welded joints, and the percentage (%) of BN was calculated according to the standard quantitative metallographic technique. The findings showed that tool wear increases when the tool rotational speed increases as a result of binder softening which is a function of the peak temperature (exceeds 1250 °C) at the tool/workpiece interface. When considering the EH46 steel trials, it was found that an increase in the tool traverse speed in friction stir welding caused a significant tool wear with 4.4% of BN in the top of the stirred zone of W9E compared to 1.1% volume fraction of BN in W8E which was attributed to the higher thermomechanical action on the PCBN tool surface. Tool wear was also found to increase with an increase in tool plunge depth as a result of the higher contact between the surface of friction stir welding tool and the workpiece
Velocity Response of the Observed Explosive Events in the Lower Solar Atmosphere: I. Formation of the Flowing Cool Loop System
We observe plasma flows in cool loops using the Slit-Jaw Imager (SJI) onboard
the Interface Region Imaging Spectrometer (IRIS). Huang et al. (2015) observed
unusually broadened Si IV 1403 angstrom line profiles at the footpoints of such
loops that were attributed to signatures of explosive events (EEs). We have
chosen one such uni-directional flowing cool loop system observed by IRIS where
one of the footpoints is associated with significantly broadened Si IV line
profiles. The line profile broadening indirectly indicates the occurrence of
numerous EEs below the transition region (TR), while it directly infers a large
velocity enhancement /perturbation further causing the plasma flows in the
observed loop system. The observed features are implemented in a model
atmosphere in which a low-lying bi-polar magnetic field system is perturbed in
the chromosphere by a velocity pulse with a maximum amplitude of 200 km/s. The
data-driven 2-D numerical simulation shows that the plasma motions evolve in a
similar manner as observed by IRIS in the form of flowing plasma filling the
skeleton of a cool loop system. We compare the spatio-temporal evolution of the
cool loop system in the framework of our model with the observations, and
conclude that their formation is mostly associated with the velocity response
of the transient energy release above their footpoints in the chromosphere/TR.
Our observations and modeling results suggest that the velocity responses most
likely associated to the EEs could be one of the main candidates for the
dynamics and energetics of the flowing cool loop systems in the lower solar
atmosphere.Comment: In Press; The Astrophysical Journal; 14 Pages; 9 Figure
ITC's strategic plan for Open Science 2021-2025:towards an open future
Open Science (OS) is an umbrella term comprising principles to increase the transparency of research. Besides Open Access to scientific articles, these principles contain public availability of reusable methods (e.g., code and tools), data, and educational materials. This document outlines a plan to achieve the transition towards OS. ITC’s Strategic Plan for OS 2021-2025 - Towards an Open Future contains five initiatives:
1.OS at ITC aims to provide guidelines and OS capacity development to address the obstacles ITC researchers encounter when doing OS.
2.The ITC Knowledge Hub will provide services and tools to access, create, and publish open research, including scientific results based on qualitative/quantitative analyses using computational workflows.
3.Open Educational Resources will be addressed by exploring options to realise Open Educational Resources at ITC and providing lecturers with guidelines and support to create them.
4.The OS Community Twente serves as an inter-disciplinary, bottom-up community to promote, learn, share, and discuss OS practices.
5.Research & Funding aims to address challenges in OS through innovative developments and user studies. A further output is to generate funding to realise the ambitious aims presented in the plan.
For a successful OS transition, the initiatives aim to address the Rewards & Recognition system, valorise Sharing & Collaboration, develop OS Knowledge & Skills, and foster Cultural change & Societal impact
Numerical Simulations of Magnetoacoustic-Gravity Waves in the Solar Atmosphere
We investigate the excitation of magnetoacoustic-gravity waves generated from
localized pulses in the gas pressure as well as in vertical component of
velocity. These pulses are initially launched at the top of the solar
photosphere that is permeated by a weak magnetic field. We investigate three
different configurations of the background magnetic field lines: horizontal,
vertical and oblique to the gravitational force. We numerically model
magnetoacoustic-gravity waves by implementing a realistic (VAL-C) model of
solar temperature. We solve two-dimensional ideal magnetohydrodynamic equations
numerically with the use of the FLASH code to simulate the dynamics of the
lower solar atmosphere. The initial pulses result in shocks at higher
altitudes. Our numerical simulations reveal that a small-amplitude initial
pulse can produce magnetoacoustic-gravity waves, which are later reflected from
the transition region due to the large temperature gradient. The atmospheric
cavities in the lower solar atmosphere are found to be the ideal places that
may act as a resonator for various oscillations, including their trapping and
leakage into the higher atmosphere. Our numerical simulations successfully
model the excitation of such wave modes, their reflection and trapping, as well
as the associated plasma dynamics
Thermo-Mechanical Effect on Poly Crystalline Boron Nitride Tool Life During Friction Stir Welding (Dwell Period)
Poly Crystalline Boron Nitride (PCBN) tool wear during the friction stir welding of high melting alloys is an obstacle to commercialize the process. This work simulates the friction stir welding process and tool wear during the plunge/dwell period of 14.8 mm EH46 thick plate steel. The Computational Fluid Dynamic (CFD) model was used for simulation and the wear of the tool is estimated from temperatures and shear stress profile on the tool surface. Two sets of tool rotational speeds were applied including 120 and 200 RPM. Seven plunge/dwell samples were prepared using PCBN FSW tool, six thermocouples were also embedded around each plunge/dwell case in order to record the temperatures during the welding process. Infinite focus microscopy technique was used to create macrographs for each case. The CFD result has been shown that a shear layer around the tool shoulder and probe-side denoted as thermo-mechanical affected zone (TMAZ) was formed and its size increase with tool rotational speed increase. Maximum peak temperature was also found to increase with tool rotational speed increase. PCBN tool wear under shoulder was found to increase with tool rotational speed increase as a result of tool’s binder softening after reaching to a peak temperature exceeds 1250 °C. Tool wear also found to increase at probe-side bottom as a result of high shear stress associated with the decrease in the tool rotational speed. The amount of BN particles revealed by SEM in the TMAZ were compared with the CFD model
Atropselective syntheses of (-) and (+) rugulotrosin A utilizing point-to-axial chirality transfer
Chiral, dimeric natural products containing complex structures and interesting biological properties have inspired chemists and biologists for decades. A seven-step total synthesis of the axially chiral, dimeric tetrahydroxanthone natural product rugulotrosin A is described. The synthesis employs a one-pot Suzuki coupling/dimerization to generate the requisite 2,2'-biaryl linkage. Highly selective point-to-axial chirality transfer was achieved using palladium catalysis with achiral phosphine ligands. Single X-ray crystal diffraction data were obtained to confirm both the atropisomeric configuration and absolute stereochemistry of rugulotrosin A. Computational studies are described to rationalize the atropselectivity observed in the key dimerization step. Comparison of the crude fungal extract with synthetic rugulotrosin A and its atropisomer verified that nature generates a single atropisomer of the natural product.P50 GM067041 - NIGMS NIH HHS; R01 GM099920 - NIGMS NIH HHS; GM-067041 - NIGMS NIH HHS; GM-099920 - NIGMS NIH HH
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