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A new microgrid scheduling model with resiliency guaranteed under the risk of both utility failure and prevailing uncertainties of renewable generation and load is proposed in this article. The proposed model minimizes the overall operating cost of the microgrid by efficiently coordinating the power supply from local distributed energy resources and the main grid. The resiliency is ensured by maintaining certain amount of flexibility in local distributed energy resources, which can be quickly deployed to keep the power supply uninterrupted whenever the utility grid suddenly goes down. In addition, the uncertainties of renewable generation and load are captured with the proposed two-stage robust optimization model. By solving the proposed optimization, the solution not only guarantees the resiliency of the microgrid by supporting possible islanding incidents without load interruption, but also ensures robustness against the randomness of renewable generation and load. Results of case studies on a typical microgrid demonstrate the effectiveness of the presented robust microgrid scheduling model.

Power system simulations with long-term data typically have large time steps, varying from one second to a few minutes. However, for PV inverter semiconductors in grid-connected applications, the minimum thermal stress cycle occurs over the fundamental grid frequency (50 or 60 Hz). This requires the time step of the fatigue simulation to be approximately 100 μs. This small time step requires long computation times to process yearly power production profiles. In this paper, we propose a fast fatigue simulation for inverter semiconductors using the quasi-static time-series simulation concept. The proposed simulation calculates the steady state of the semiconductor junction temperature using a fast Fourier transform. The small thermal cycling during a switching period and even over the fundamental waveform is disregarded to further accelerate the simulation speed. The resulting time step of the fatigue simulation is 15 min, which is consistent with the solar dataset. The error of the proposed simulation is 0.16% compared to the fatigue simulation results using the complete thermal stress profile. The error of the proposed method is significantly less than the conventional averaged thermal profile. A PV inverter that responds to a transactive energy system is simulated to demonstrate the use of the proposed fatigue simulation. The proposed simulation has the potential to cosimulate with system-level simulation tools that also adopt the quasi-static time-series concept.

Chilling and frost conditions impose major yield restraints to wheat crops in Australia and other temperate climate regions. Unpredictability and variability of field frost events are major impediments for cold tolerance breeding. Metabolome and lipidome profiling were used to compare the cold response in spikes of cold-tolerant Young and sensitive variety Wyalkatchem at the young microspore (YM) stage of pollen development. We aimed to identify metabolite markers that can reliably distinguish cold-tolerant and sensitive wheat varieties for future cold-tolerance phenotyping applications. We scored changes in spike metabolites and lipids for both varieties during cold acclimation after initial and prolonged exposure to combined chilling and freezing cycles (1 and 4 days, respectively) using controlled environment conditions. The two contrasting wheat varieties showed qualitative and quantitative differences in primary metabolites involved in osmoprotection, but differences in lipid accumulation most distinctively separated the cold response of the two wheat lines. These results resemble what we previously observed in flag leaves of the same two wheat varieties. The fact that this response occurs in tissue types with very different functions indicates that chilling and freezing tolerance in these wheat lines is associated with re-modelling of membrane lipid composition to maintain membrane fluidity.

ConformTM is an extrusion process, which has been in use since the 1970s. Although it is primarily used with aluminium or copper rod/powder feedstocks, work at the Univ. Sheffield over the last decade has involved the use of titanium feedstocks for various applications. This paper expands on this knowledge by utilising low cost, aerospace titanium alloy swarf, which is the largest waste product from the manufacturing of aerospace titanium components. Swarf is fed into a ConformTM extrusion machine at room temperature and is fully consolidated into round wire/rod profiles in one, solid-state step, using modified tooling for titanium. Such wire can be used for additive manufacture or welding wire. To date there has been numerous successful trials in this challenging process, including the production of both 10 mm commercially pure titanium rod (from powder) and, more importantly, the production of 5 mm diameter Ti-6Al-4V wire from swarf. The material produced has since been characterised using light and electron microscopy and mechanical properties determined using tensile testing and microhardness indenting.

Frost research to improve genetics or management solutions requires a robust experimental design that minimizes the effects of all other variables that can cause plant damage except for the treatment (frost). Controlled environment facilities cannot faithfully replicate field radiative frost processes, but field studies are limited by the reliability of field methods to exclude frost. An effective field frost exclusion method needs to prevent frost damage while not impacting growing microclimate or yield, and be automatic, modular, mobile, and affordable. In this study, we designed an effective prototype treatment with these features for field frost research that uses diesel heating. The effectiveness of the plot heater to provide an unfrosted control is evaluated by monitoring canopy temperature (CT) and air temperature during frost events, showing that these remain above zero in the heated plots when ambient temperature drops below zero. We find that the plot heater method can prevent potential frost damage at the plot-scale, while not appearing to have an impact on either plant development or yield components. This offers a potential new tool for frost field crop researchers to incorporate a plot-scale control into their experimental design.

Does art – literature – have a place in the ethical life? Can it practice moral formation? Moral philosophers from the nineteenth century through the modern era have answered both questions in the affirmative. In this paper, I argue that several of the former, such as G. E. Moore and Arthur Schopenhauer, inspired the modernist writers Virginia Woolf and Thomas Mann to use distinctively modern narrative strategies to morally form their readers. To establish a vocabulary useful in explaining how and to what end they did so, a brief exposition of contemporary virtue theorists opens the paper. Analyses of each writer follow; first, Mann relies on irony, emotional and deliberative narration, and the sublime to provoke the reader into confronting their biases on ethical-aesthetic problems throughout Death in Venice. Woolf creates ordinary “common meeting-places” and uses stream-of-consciousness narration to engender readers’ sympathy in “The Mark on the Wall” and “Mrs. Dalloway in Bond Street.” Despite those strategic differences, however, both draw their readers into morally valent individual psychological realities without trying to destroy them. In this way, their texts are capable of re-creating the reader as “finely aware and richly responsible,” a faculty which I then situate in late modernity’s nascent discomfort with and inability to disavow grand narratives. The paper concludes that Woolf and Mann’s formative modernism is a critical midpoint between modernity and poststructuralist postmodernity.

The study of marginalized students in higher education has been critiqued for focusing research attention on common areas of struggle rather than examining areas of success. This study attempted to address that gap, particularly at faith-based, predominantly White institutions as represented by the Council for Christian Colleges & Universities. The purpose of this study was to explore the lived experiences of high-achieving students from historically marginalized groups involved in the Act Six program--a rigorous comprehensive urban leadership scholarship program--at four predominantly White CCCU institutions. The 30 participants defined their experience in terms of their sense of belonging, as measured by their perceptions of whether they as a student mattered (individual sense of belonging), and whether diversity mattered to the institution (institutional sense of belonging). Data from interviews indicated that peer support, institutional support, academics and faculty engagement, and campus-climate contributions and challenges all played a role in the student experience. The resulting implications for practice include pragmatic ideas for fostering a sense of belonging through the cadre model and campus community, within the classroom and the academic experience, and through the actions of senior leaders. Although this research documents a high degree of success for Act Six students individually, as well as of this particular program at the sponsoring institutions, the inconsistencies encountered by students in relation to their sense of belonging emphasizes the importance of educational leaders expanding efforts to develop hospitable campus services and a supportive campus climate.

The Act Six program includes full-need, full-tuition student scholarships, extensive training and preparation for students prior to matriculation, and mentorship throughout their time on campus. The purpose of this research was to explore institutional decisions and implications in initiating and sustaining an Act Six partnership. Through an exploratory case analysis design, the views of staff, faculty, and administrators at four Act Six partner universities, as well as institutional documents and data, were explored. Ultimately, this initiative appears to be one successful strategy for developing the institutional capacity to respond to the significant changes in student demographic trends, while honoring the biblical call and developing a justice orientation toward diversity.

In this study, the low velocity impact properties of rotationally molded skin-foam-skin sandwich structures were investigated experimentally since there is a need for a greater understanding of the impact behavior of these composites in service to extend the range of their applications. Polyethylene rotationally molded sandwich structures were manufactured at various skin and core layer thickness combinations and tested using an instrumented low velocity drop weight impact testing machine at 20-100 J impact energy levels, at room temperature. This allowed the identification of the impact response, failure mode, and the effects of the skin and core layer thickness on impact resistance. Force-deflection curves, maximum force, contact time, maximum deflection versus impact energy curves were analyzed. Samples were seen to fail due to the indentation dart piercing the upper and lower skins, with crushing and consolidation seen in the core foamed layer. Delamination at the core/skin interface was not observed. It was found that fracture initiates from the lower skin and then continues to grow to the upper skin via the foamed core layer. The impact resistance was noted to increase with increasing skin and core layer thickness; though an increase in skin layer thickness had a greater contribution than an increase in the core layer thickness., INTRODUCTION Sandwich composite structures are made from a single material such as polyethylene (PE) using the rotational molding process, have two solid skins separated by a foam core (Fig. 1) [...]