Simulation of a maneuvering aircraft using a panel method

We present a method for numerical simulations of a maneuvering aircraft, which uses a first-order unsteady panel method as the only source of aerodynamic forces and moments. By using the proposed method, it is possible to simulate a motion of an aircraft, while the only required inputs are geometry and inertia characteristics, which significantly reduces the time required to start the simulation. We validated the method by a comparison of recordings of flight parameters (position, velocities, accelerations) from an actual acrobatic flight of a glider and the results obtained from the simulations. The simulation was controlled by deflections of control surfaces recorded during the actual flight. We found a reasonable agreement between the experimental data and the simulation. The design of our method allows to evaluate not only the integral kinematic quantities but also instant local pressure and inertia loads. This makes our method useful also for a load evaluation of an aircraft. A significant advantage of the proposed method is that only an ordinary workstation computer is required to perform the simulation

Heterogeneity in the kinetics of nuclear proteins and trajectories of substructures associated with heterochromatin

<p>Abstract</p> <p>Background</p> <p>Protein exchange kinetics correlate with the level of chromatin condensation and, in many cases, with the level of transcription. We used fluorescence recovery after photobleaching (FRAP) to analyse the kinetics of 18 proteins and determine the relationships between nuclear arrangement, protein molecular weight, global transcription level, and recovery kinetics. In particular, we studied heterochromatin-specific heterochromatin protein 1β (HP1β) B lymphoma Mo-MLV insertion region 1 (BMI1), and telomeric-repeat binding factor 1 (TRF1) proteins, and nucleolus-related proteins, upstream binding factor (UBF) and RNA polymerase I large subunit (RPA194). We considered whether the trajectories and kinetics of particular proteins change in response to histone hyperacetylation by histone deacetylase (HDAC) inhibitors or after suppression of transcription by actinomycin D.</p> <p>Results</p> <p>We show that protein dynamics are influenced by many factors and events, including nuclear pattern and transcription activity. A slower recovery after photobleaching was found when proteins, such as HP1β, BMI1, TRF1, and others accumulated at specific foci. In identical cells, proteins that were evenly dispersed throughout the nucleoplasm recovered more rapidly. Distinct trajectories for HP1β, BMI1, and TRF1 were observed after hyperacetylation or suppression of transcription. The relationship between protein trajectory and transcription level was confirmed for telomeric protein TRF1, but not for HP1β or BMI1 proteins. Moreover, heterogeneity of foci movement was especially observed when we made distinctions between centrally and peripherally positioned foci.</p> <p>Conclusion</p> <p>Based on our results, we propose that protein kinetics are likely influenced by several factors, including chromatin condensation, differentiation, local protein density, protein binding efficiency, and nuclear pattern. These factors and events likely cooperate to dictate the mobility of particular proteins.</p

Managing floodplains using nature‐based solutions to support multiple ecosystem functions and services

Floodplains include unique environments shaped over a long time horizon along rivers and smaller streams and formed by alluvial sediments. As floodplains are flat, often with highly fertile and well-accessible land, they have become the intrinsic focus of human society—while providing a variety of goods and ecosystem services. Intensive land use of floodplains is degrading their natural values and significantly reducing their ecosystem functions and services. A significant part of these key services is related with the ability of floodplains to retain water and nutrients, which can be understood as a flood control and a water-retention function. Although these ecosystems serve a number of other basic functions, the importance of floodplains as a place for water retention during extreme discharges caused by intense rainfall or snowmelt and the supply of water in times of drought are essential under conditions of global change. In order to increase the ability of floodplains to perform these functions, it is increasingly required to preserve the connectivity of rivers with surrounding floodplains and adapt human activities to maintain and restore river ecosystems. This article reviews the recent understanding of floodplain delineation, the most common causes of disturbance, the ecosystem functions being performed, discussing in turn the measures being considered to mitigate the frequency and magnitude of hydrologic extremes resulting from ongoing environmental changes

Musica viva in schola XXVII.

Title in English: Musica viva in schola XXVII. The proceeding from the jubilee 30th international music-educational conference Musica viva in schola continues the tradition of publishing MVIS conference papers from previous years. The contributions respond to current issues in music education and the arts and culture, including modern approaches in education and research projects. In addition to the above, the current year also focuses on musical traditions in music education. Authors include academics and researchers, as well as music didactics, practitioners, and representatives of national and international music education societies

Postupy lomu Bílina v období dokončení hlavních technologických změn v dopravě

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta hornicko-geologická. Institut hornického inženýrství a bezpečnosti (542

The design the lines for temperature test of control section in the company of C.B.G. Impex s.r.o.

Import 08/08/2007Prezenční345 - Katedra mechanické technologi

Soil denudation rates in an old‐growth mountain temperate forest driven by tree uprooting dynamics, Central Europe

Tree uprooting may distinctly affect landscape dynamics and slope denudation. Little is known, however, about the corresponding soil redistribution rates (erosion and accumulation) on either a long‐term (millennia; 10Be) or a short‐term (decades; 239+240Pu) scale. We determined these rates in a well‐investigated forest reserve (Zofinsky primeval forest, Czech Republic) using complementary techniques: nuclides in soils and tors to derive short‐ to long‐term rates and monitoring data (43 years) of repeated tree censuses using tree uprooting data. Temporal trends of soil erosion rates were obtained by dating the timing of exhumation (10Be) of tors. The average long‐term denudation rates were about 30–40 t km−2 yr−1. It seems that these rates varied over time with probably a maximum during the Pleistocene/Holocene transition (58–91 t km−2 yr−1). 239+240Pu activities in the soils identified soil redistribution rates of 50 to >100 t km−2 yr−1 for the last decades and agree with results from the tree uprooting monitoring (<92 t km−2 yr−1). In‐situ 10Be in soils gave similar denudation rates (58–76 t km−2 yr−1). Meteoric 10Be provided a mean residence time of a soil particle of 33–100 ka supporting the measured average long‐term erosion rates. Soil aggregates indicated stable physical conditions meaning that soil mass redistribution occurs only sporadically. It seems that the main driving factors of denudation changed over time. An erosion peak at the Pleistocene/Holocene transition (climate change) seems likely but needs further proof. Over the last few millennia, tree uprooting seems the main driver of soil erosion

Soil erosion rates during the Holocene continuity in a forest‐steppe landscape

Despite a long-term human impact, Central and Eastern Europe exhibit patches of steppe ecosystems having the highest plant species diversity worldwide. These unique ecosystems have persisted over millennia even though the local climatic conditions would support the formation of a closed forest. Several sources of disturbances have contributed to the persistence of the forest-steppe landscape such as grazing, fire events and human impact. These disturbances have been recorded in local erosion rates. To gain a deeper understanding of the soil dynamics we aimed at deciphering the long- and short-term erosion rates and the age of the soil mantle. The steppes in Transylvania, Romania, were studied to find evidence of a Holocene continuity of grasslands. Long-term (millennia) average erosion rates were determined using meteoric 10Be in soils and in situ 10Be of rock outcrops (scarp). Long-term rates were also estimated by the percolation theory. Short-term (last few decades) erosion rates were obtained from 239+240Pu in soils. The soils started to form prior to the Last Glacial Maximum, probably during the Eemian Interglacial. The average, long-term erosion rates varied between 0.18 and 0.63 t ha−1 yr−1. These rates are slightly elevated compared to expected soil erosion rates. The soils of the Transylvanian Plain formed over a long period and reached a quasi-steady state (soil production equals denudation) that contributed to the maintenance of a biodiversity-rich forest-steppe landscape. The slightly elevated erosion rates are an effect of factors that contributed to the Holocene continuity (fire, grazing) and indicate open rather than a forested character of the landscape during soil development. During the last few decades, the erosion rates increased by a factor of 5–10, with values in the range of 1.31–4.05 t ha−1 yr−1. These large differences are caused by changes in human management of the soils. The biodiversity-rich forest-steppe landscapes are now under threat

Soil erosion affected by trees in a tropical primary rain forest, Papua New Guinea

Trees have the ability to distinctly determine soil evolution and hillslope processes through mechanical soil disturbances such as tree uprooting. Recent findings have resulted in new biogeomorphic state transition models for old-growth forests in the temperate climate zone. The situation in tropical forests, however, is mostly unknown. Here, we focus on determining short- (decades) and long-term (millennia) soil erosion rates and the biogeomorphic role of trees on hillslope dynamics in the species-rich Wanang primeval tropical forest, Papua New Guinea. We hypothesized that trees play a significant role in hillslope dynamics on a background of powerful soil erosion dominated by abiotic factors, and that this role has potentially intensified over the last decades. The long-term soil erosion was assessed using the meteoric 10Be levels in three soil profiles along the whole depth gradient along with one natural outcrop. The recent soil erosion rate was determined using 239+240Pu levels in the uppermost soil layers. The specific role of trees in hillslope processes was evaluated based on repeated tree censuses of 65,535 tree individuals, calculating the tree mortality rate and modeling the soil volume affected by uprooted trees and by the in situ decay of the root systems of broken trees. Soil erosion was 6.25 m3 ha−1 yr−1 over the long term and indeed did increase during the last decades. While this rate was significantly affected by trees, they were not the main factor, with circa 0.95 m3 ha−1 influenced annually by uprooting, and an additional 0.61 m3 ha−1 by the in situ decay of root systems. These results reflect a forest ecosystem that is currently in the biogeomorphic stage of biotic/abiotic feedbacks