Inactivation of coronaviruses by heat Kampf, G.; Voss, A.; Scheithauer, S.
The Journal of hospital infection,
06/2020, Letnik:
105, Številka:
2
Journal Article
This work presents results of dynamic “one-minus-cosine” gust load simulations for a flying wing configuration. The in-house toolbox Loads Kernel is used for the loads analysis of the free flying ...aircraft. Flight mechanical characteristics are captured by application of a non-linear equation of motion in the time domain. The underlying aerodynamic methods are the Vortex Lattice and the Doublet Lattice Method with a rational function approximation (RFA) for unsteady simulations in the time domain. The structural model was created using DLR's parametric ModGen/Nastran design process. The structure is optimized for minimum structural weight with typical design load cases including maneuver, gust and landing loads. In this article, the focus lies on gust encounters and the flight characteristics of a flying wing configuration. It differs from classical configurations (wing-fuselage-empennage) due to a pronounced nose-up pitching motion when the aircraft enters the gust field. Finally, a flight controller is designed to increase the pitching stability. This is essential for the flight of a naturally unstable configuration. It is shown that the loads during a gust encounter increase significantly. The influence on the structural weight is small as the layout is very robust and the required material thickness is below the minimum thickness in most areas.
The context in which service is delivered and experienced has, in many respects, fundamentally changed. For instance, advances in technology, especially information technology, are leading to a ...proliferation of revolutionary services and changing how customers serve themselves before, during, and after purchase. To understand this changing landscape, the authors engaged in an international and interdisciplinary research effort to identify research priorities that have the potential to advance the service field and benefit customers, organizations, and society. The priority-setting process was informed by roundtable discussions with researchers affiliated with service research centers and networks located around the world and resulted in the following 12 service research priorities:
stimulating service innovation,
facilitating servitization, service infusion, and solutions,
understanding organization and employee issues relevant to successful service,
developing service networks and systems,
leveraging service design,
using big data to advance service,
understanding value creation,
enhancing the service experience,
improving well-being through transformative service,
measuring and optimizing service performance and impact,
understanding service in a global context, and
leveraging technology to advance service.
For each priority, the authors identified important specific service topics and related research questions. Then, through an online survey, service researchers assessed the subtopics’ perceived importance and the service field’s extant knowledge about them. Although all the priorities and related topics were deemed important, the results show that topics related to transformative service and measuring and optimizing service performance are particularly important for advancing the service field along with big data, which had the largest gap between importance and current knowledge of the field. The authors present key challenges that should be addressed to move the field forward and conclude with a discussion of the need for additional interdisciplinary research.
The DLR Future Fighter Demonstrator (FFD) is a highly agile, two-seated aircraft with twin-engines equipped, a reheat and a design flight speed extending into the supersonic regime (up to Ma=2.0). ...Based on a given conceptual design, the presented work focuses on the aeroelastic modeling, including structures, masses and aerodynamics. Using the models, a comprehensive loads analysis with 688 maneuver load cases, covering the whole flight envelope, is performed. Comparing the results obtained from aerodynamic panel methods (VLM and ZONA51) with higher fidelity results obtained from CFD, the necessity of CFD based maneuver loads analysis in preliminary design of such fighter configuration is shown, as it leads to physically different as well as higher loads. The rigorous application of CFD is a heavy burden during the preliminary design, but this work demonstrates that it is doable as of today. Finally, the model is subject to structural optimization, demonstrating that the differences in loads result in a heavier primary structural net mass with ≈3.3t for the approach based on aerodynamic panel methods and ≈4.1t for the CFD based approach. Because all remaining models are unchanged, this difference in mass can be clearly attributed to the physical differences in the flow solutions obtained from the panel methods and CFD.
In this paper we further develop a model for the heating of coronal loops by Alfvén wave turbulence (AWT). The Alfvén waves are assumed to be launched from a collection of kilogauss flux tubes in the ...photosphere at the two ends of the loop. Using a three-dimensional magnetohydrodynamic model for an active-region loop, we investigate how the waves from neighboring flux tubes interact in the chromosphere and corona. For a particular combination of model parameters we find that AWT can produce enough heat to maintain a peak temperature of about 2.5 MK, somewhat lower than the temperatures of 3-4 MK observed in the cores of active regions. The heating rates vary strongly in space and time, but the simulated heating events have durations less than 1 minute and are unlikely to reproduce the observed broad differential emission measure distributions of active regions. The simulated spectral line nonthermal widths are predicted to be about 27 km s−1, which is high compared to the observed values. Therefore, the present AWT model does not satisfy the observational constraints. An alternative "magnetic braiding" model is considered in which the coronal field lines are subject to slow random footpoint motions, but we find that such long-period motions produce much less heating than the shorter-period waves launched within the flux tubes. We discuss several possibilities for resolving the problem of producing sufficiently hot loops in active regions.
Efficient calving surveillance is essential for avoiding stillbirth due to unattended dystocia. Calving sensors can help detect the onset of parturition and thus ensure timely calving assistance if ...necessary. Tail-raising is an indicator of imminent calving. The objective of this study was to evaluate a tail-mounted inclinometer sensor (Moocall Ltd., Dublin, Ireland) and to monitor skin integrity after sensor attachment. Cows (n = 157) and heifers (n = 23) were enrolled at 275 d post insemination, and a sensor was attached to each cow's tail. Investigators checked for signs indicating the onset of stage II of parturition, verified the position of the sensor, and evaluated the skin integrity of the tail above and below the sensor hourly for 24 h/d. We used 5 different intervals (i.e., 1, 2, 4, 12, and 24 h until calving) to calculate sensitivity and specificity. Sensors continuously remained on the tail (i.e., within 3 cm of the initial attachment position) after initial attachment until the onset of calving in only 13.9% of animals (n = 25). Sensors were reattached until a calving event occurred (51.6%) or the animal was excluded for other reasons (34.4%). In 31 animals the sensor was removed because the tail was swollen or painful. Heifers were significantly less likely than cows to lose a sensor but more likely to experience tail swelling or pain. Depending on the interval preceding the onset of parturition, sensitivity varied from 19 to 75% and specificity from 63 to 96%.
Service organizations are increasingly managing customer experiences to promote differentiation and customer loyalty. This article examines the design of experience-centric services, particularly the ...design of their context. Drawing on relevant literature in service and experience design, the authors develop a theory-based set of propositions for experience design.The propositions are then investigated empirically by means of 17 case studies of design agencies, consulting firms, and experience-centric service providers in different industries. Strong support was found for the designing of “customer journeys” and “touchpoints,” for sensory design, and for the designing of a dramatic structure of events. In addition, the engagement of employees, the management of fellow customers, and the close coupling of backstage employees and frontstage activities represent promising new frontiers in experience design. By identifying the current design practices of leaders in experience design, this study both informs this practice and presents a unique perspective on the design of service delivery systems.
Abstract Since being first reported in an ear swab in 2009, and in blood cultures in 2011, invasive infections with Candida auris have been reported in many countries across several continents. In ...this article we review current knowledge of the epidemiology of this emerging multidrug-resistant pathogen. The importance of species identification, and the inadequacies of many commonly used identification systems, is considered. We recommend that hospitals develop their own policies for the prevention and control of infections with this pathogen. Elements of such policies, and the limitations of the existing knowledge base, are discussed.
Summary
A majority of environmental studies describe microbiomes at coarse scales of taxonomic resolution (bacterial community, phylum), ignoring key ecological knowledge gained from finer‐scales and ...microbial indicator taxa. Here, we characterized the distribution of 940 bacterial taxa from 41 streams along an urbanization gradient (0%–83% developed watershed area) in the Raleigh‐Durham area of North Carolina (USA). Using statistical approaches derived from macro‐organismal ecology, we found that more bacterial taxa were classified as intolerant than as tolerant to increasing watershed urbanization (143 vs 48 OTUs), and we identified a threshold of 12.1% developed watershed area beyond which the majority of intolerant taxa were lost from streams. Two bacterial families strongly decreased with urbanization: Acidobacteriaceae (Acidobacteria) and Xanthobacteraceae (Alphaproteobacteria). Tolerant taxa were broadly distributed throughout the bacterial phylogeny, with members of the Comamonadaceae family (Betaproteobacteria) presenting the highest number of tolerant taxa. Shifts in microbial community structure were strongly correlated with a stream biotic index, based on macroinvertebrate composition, suggesting that microbial assemblages could be used to establish biotic criteria for monitoring aquatic ecosystems. In addition, our study shows that classic methods in community ecology can be applied to microbiome datasets to identify reliable microbial indicator taxa and determine the environmental constraints on individual taxa distributions along environmental gradients.
A series of novel organic cage compounds 1−4 were successfully synthesized from readily available starting materials in one-pot in decent to excellent yields (46−90%) through a dynamic covalent ...chemistry approach (imine condensation reaction). Covalently cross-linked cage framework 14 was obtained through the cage-to-framework strategy via the Sonogashira coupling of cage 4 with the 1,4-diethynylbenzene linker molecule. Cage compounds 1−4 and framework 14 exhibited exceptional high ideal selectivity (36/1−138/1) in adsorption of CO2 over N2 under the standard temperature and pressure (STP, 20 °C, 1 bar). Gas adsorption studies indicate that the high selectivity is provided not only by the amino group density (mol/g), but also by the intrinsic pore size of the cage structure (distance between the top and bottom panels), which can be tuned by judiciously choosing building blocks of different size. The systematic studies on the structure−property relationship of this novel class of organic cages are reported herein for the first time; they provide critical knowledge on the rational design principle of these cage-based porous materials that have shown great potential in gas separation and carbon capture applications.
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