Design of a structurally optimized bioinspired structural arrangement of carbon composite fuselage of unmanned aerial vehicle based on parametric modeling

Currently, the industry of unmanned aerial vehicles (UAV) is actively developing. They perform a wide range of different civilian and military tasks. Depending on the task, stringent requirements are imposed on the design, but the key ones are low weight, high strength and survivability. Satisfying these requirements will increase the payload mass and extend the life of the product. This can be ensured by the use of polymer composite materials (PCM) based on carbon fibers and new structural arrangement. This is especially true for the main element of the UAV frame –the fuselage. The work is devoted to an urgent task –the development of a new UAV composite structural layout. Structural-optimized structures are considered: bioinspired, auxetic, grid structures. A comparison of the developed options with the classical structure of the frame is carried out. A variant that exceeds the classical layout in terms of mass and strength up to 25% is selected. Main layout parameters are determined

Design of a structurally optimized bioinspired structural arrangement of а polymer composite regional aircraft tail fin

Aircraft frame elements are highly responsible elements. They are subject to stringent requirements for strength, stability, resource. Often these requirements contradict each other, especially if it is necessary to ensure the minimum mass of the product. However, it is necessary to improve the characteristics of aircraft. Nevertheless, the optimization of the frame has almost exhausted itself. The power frame consists of longitudinal and transverse elements. It is possible to improve the characteristics of structural arrangement by using polymer composite materials based on glass and carbon fibers. This will improve the design characteristics due to high specific properties. In addition, one of the directions is the development of new bioinspired structural layout based on natural analogues. The work is devoted to the actual task of searching and choosing new structural arrangement for the aircraft tail. The paper considers five variants of structural layout, including the classical original design. The advantage of the bioinspired variant in terms of mass and displacement is shown

Design of a structurally optimized bioinspired structural arrangement of a polymer composite wing

Developing trends in designing and manufacturing products made of polymer composite materials allow us to create previously unattainable structures. These include bioinspired structural layouts inspired by objects of nature, for example, the wings of insects, plants, and others. In turn, the structural layout of the wings of aircraft has reached its limit in terms of optimization in its classic form. The work is devoted to an urgent task –the choice of a bioinspired layout for an aircraft wing. A comparison of classic structural arrangement with a bioinspired structure is carried out. The total number of options considered is 14. The structure of the bioinspired wing was chosen based on the action of the load and stress distribution according to the results of preliminary calculations inspired by insect wings. The advantage of wings of a bioinspired design over classical ones by weight up to 32% is shown. The results of the initial stage of studies of bioinspired wings are presented

Sheaves on fibered threefolds and quiver sheaves

This paper classifies a class of holomorphic D-branes, closely related to framed torsion-free sheaves, on threefolds fibered in resolved ADE surfaces over a general curve C, in terms of representations with relations of a twisted Kronheimer--Nakajima-type quiver in the category Coh(C) of coherent sheaves on C. For the local Calabi--Yau case C\cong\A^1 and special choice of framing, one recovers the N=1 ADE quiver studied by Cachazo--Katz--Vafa.Comment: 13 pages, 2 figures, minor change

Повышение маневренных возможностей теплофикационных парогазовых установок за счет применения электрокотлов

The paper contains the results of efficiency evaluation  of using the electric boilers to improve maneuver capabilities of the cogeneration combined cycle power plants (as an example, 230 MW combined cycle unit of Minsk CHP-3) in comparison with the traditional steam-turbine units of cogeneration power plants.Приведены результаты расчета эффективности применения электрокотлов для повышения маневренных возможностей теплофикационных парогазовых установок (на примере ПГУ-230 Минской ТЭЦ-3) в сравнении с традиционными паротурбинными установками ТЭЦ

К вопросу ограничения нагрузки отопительных отборов для получения резервной мощности теплофикационных турбоагрегатов

The paper considers problems pertaining to limitation of heating extraction load of power-and-heat supply turbo-generators with the purpose to obtain a reserve power.Graphical dependences for determination of time period within which an indoor temperature is decreased by 1 оС according to relative heat expenditure for heating and a value of outdoor temperature. The paper reveals the possibility to limit a heating load by 20% within some hours time while observing comfortable indoor conditions.Рассматриваются вопросы ограничения нагрузки отопительных отборов теплофикационных турбоагрегатов для получения резервной мощности.Приводятся графические зависимости для определения времени, в течение которого температура внутри помещения снижается на 1 оС в зависимости от относительного расхода теплоты на отопление и температуры наружного воздуха. Показывается возможность ограничения отопительной нагрузки примерно на 20 % в течение нескольких часов при соблюдении комфортных условий в помещении

Structural origin of gap states in semicrystalline polymers and the implications for charge transport

We quantify the degree of disorder in the {\pi}-{\pi} stacking direction of crystallites of a high performing semicrystalline semiconducting polymer with advanced X-ray lineshape analysis. Using first principles calculations, we obtain the density of states of a system of {\pi}-{\pi} stacked polymer chains with increasing amounts of paracrystalline disorder. We find that for an aligned film of PBTTT the paracrystalline disorder is 7.3%. This type of disorder induces a tail of trap states with a breadth of ~100 meV as determined through calculation. This finding agrees with previous device modeling and provides physical justification for the mobility edge model.Comment: Text and figures are unchanged in the new version of the file. The only modification is the addition of a funding source to the acknowledgment

CDF II production farm project

We describe the architecture and discuss our operational experience in running the off-line reconstruction farm of the CDFII experiment. The Linux PC-based farm performs a wide set of tasks,ranging from producing calibrations and primary event reconstruction to large scale ntuple production.The farm control software uses a standard Condor toolkit and the data handling part is based on SAM (Sequential Access via Metadata)software.During its lifetime,the CDFII experiment will integrate a large amount of data (several petabytes)and the data processing chain is one of the key components of the successful physics program of the experiment