Dual Channel Control with DC Fault Ride Through for MMC-based, Isolated DC/DC Converter

This study is sponsored by the Engineering and Physical Sciences Research Council (EPSRC) grant no EP/K006428/1, 2013.D. Jovcic and H. Zhang are with the School of Engineering, University of Aberdeen, AB24 3UE, U.K. ([email protected], [email protected]).Peer reviewedPostprin

From Contemplation to Action: Mechanisms of Change in the Mentoring Academy

Mentoring is fundamental to the professional development of research scientists in academic health centers (AHC). Qualified mentors can support the development of competencies considered most significant in training research scientists. Yet AHC faculty may have little preparation in and knowledge of how to mentor. Emerging AHC mentor academies provide educational environments whereby faculty can learn the art and practice of mentoring. However, little is known about their effectiveness. Using the Transtheoretical Change Model (TTM), this study explored how 23 mentors used newly learned information to change their communication styles and develop shared expectations with mentees. Based on an inductive analysis of 46 reflective writing assignments, the results showed that the mentor academy enabled progress through the stages of contemplation and preparation, however, mentors rarely implemented new knowledge to make changes in their approach to mentoring. The authors suggest instructional strategies that will promote actionable change and accountability for implementation

Assessing Participant Group Affiliation and Attitudes Towards CTSI Services

Analyzing open-ended survey text responses holds the capacity to yield greater insight about participants’ perceptions of clinical translational science institute (CTSI) initiatives. Few translational research studies have explored their effectiveness. The aim of this mixed methods analysis was to assess participant perspectives of the impact and effectiveness of our CTSI program and services. We selected two open-ended survey question items (how CTSI benefitted research, and the most important impact of the research facilitated by the CTSI) from a larger set and compared responses by participant affiliations (clinical/non-clinical; lab/non-lab). We used a three-step analysis. First, nodes were generated using NVivo word frequency function. Next, with the aid of Python, we used sentiment analysis to classify each node (as positive, negative, or neutral) to indicate participant ratings toward their experiences with the CTSI and computed the average differences between groups. Third, we selected nodes that met pre-established criteria and report the qualitative distinctions. We recommend using precisely worded open-ended questions in future annual surveys or administering a survey using only opened-ended questions every six months

Nonlinear vibration of hypoid gear with backlash

Due to the machining errors, alignment error, wear, tear and time varying stiffness of hypoid teeth, the vibration of hypoid gears is inevitably produced in the course of working, and its vibration and noise is the main sources of vibration and noise in the automobile transmission. Study on nonlinear vibration and noise of the hypoid gear pair, and investigating on reducing its vibration and noise are of great significance. Firstly, a simplified nonlinear vibration model of the hypoid gears of main reducer, with considering the time-varying teeth stiffness and teeth surface friction damping, was established. Then, a numerical simulation method was employed to simulate different gear backlash effects on the hypoid gear vibration behaviors caused by the gear worn, and effects on the gear non-linear vibration from different work speeds of gear and different loading torques were investigated. In order to help to explain the non-linear vibration phenomenon of the hypoid gears, the 2-D phase plane diagram and the 3-D trajectory were employed. Lastly, the bench test was carried out to verify the simulation results on vibration of hypoid gears with backlash

Enhancing cutting tool sustainability based on remaining useful life prediction

As a critical part of machining, cutting tools are of great importance to sustainability enhancement. Normally, they are underused, resulting in huge waste. However, the lack of reliable support leads to a high risk on improving the cutting tool utilization. Aiming at this problem, this paper proposes an approach to enhance the cutting tool sustainability. A non-linear cutting tool remaining useful life prediction model is developed based on tool wear historical data. Probability distribution function and cumulative distribution function are used to quantize the uncertainty of the prediction. Under a constant machining condition, a cutting tool life is extended according to its specific remaining useful life prediction, rather than a unified one. Under various machining conditions, machining parameters are optimized to improve efficiency or capability. Cutting tool sustainability is assessed in economic, environmental and social dimensions. Experimental study verifies that both material removal rate and material removal volume are improved. Carbon emission and cutting tool cost are also reduced. The balance between benefit and risk is achieved by assigning a reasonable confidence level. Cutting tool sustainability can be enhanced by improving cutting tool utilization at controllable risk.©2020 Elsevier. This manuscript version is made available under the Creative Commons Attribution–NonCommercial–NoDerivatives 4.0 International (CC BY–NC–ND 4.0) license, https://creativecommons.org/licenses/by-nc-nd/4.0/fi=vertaisarvioitu|en=peerReviewed

Subsea DC collection grid with high power security for offshore renewables

This work was supported by the Engineering and Physical Sciences Research Council [grant number EP/K006428/1]; and the European Regional Development Fund [grant number LUPS/ERDF/2010/4/1/0164].Peer reviewedPostprin

Synthesis and Biological Evaluation of Ezetimibe Analogs as Possible Cholesterol Absorption Inhibitors

In order to investigate the SAR of Ezetimibe analogs for cholesterol absorption inhibitions, amide group and electron-deficient pyridine ring were introduced to the C-(3) carbon chain of Ezetimibe. Eight new derivatives of the 2-azetidinone cholesterol absorption inhibitors have been synthesized, and all of them were enantiomerically pure. All the new compounds were evaluated for their activity to inhibit cholesterol absorption in hamsters, and most of them showed comparable effects in lowering the levels of total cholesterol in the serum

Advanced Denoising for X-ray Ptychography

The success of ptychographic imaging experiments strongly depends on achieving high signal-to-noise ratio. This is particularly important in nanoscale imaging experiments when diffraction signals are very weak and the experiments are accompanied by significant parasitic scattering (background), outliers or correlated noise sources. It is also critical when rare events such as cosmic rays, or bad frames caused by electronic glitches or shutter timing malfunction take place. In this paper, we propose a novel iterative algorithm with rigorous analysis that exploits the direct forward model for parasitic noise and sample smoothness to achieve a thorough characterization and removal of structured and random noise. We present a formal description of the proposed algorithm and prove its convergence under mild conditions. Numerical experiments from simulations and real data (both soft and hard X-ray beamlines) demonstrate that the proposed algorithms produce better results when compared to state-of-the-art methods.Comment: 24 pages, 9 figure