4,973 research outputs found
Simulation and visualization of face seal motion stability by means of computer generated movies
A computer aided design method for mechanical face seals is described. Based on computer simulation, the actual motion of the flexibly mounted element of the seal can be visualized. This is achieved by solving the equations of motion of this element, calculating the displacements in its various degrees of freedom vs. time, and displaying the transient behavior in the form of a motion picture. Incorporating such a method in the design phase allows one to detect instabilities and to correct undesirable behavior of the seal. A theoretical background is presented. Details of the motion display technique are described, and the usefulness of the method is demonstrated by an example of a noncontacting conical face seal
On the accuracy of the ALI method for solving the radiative transfer equation
We solve the integral equation describing the propagation of light in an
isothermal plane-parallel atmosphere of optical thickness , adopting a
uniform thermalization parameter . The solution given by the ALI
method, widely used in the field of stellar atmospheres modelling, is compared
to the exact solution. Graphs are given that illustrate the accuracy of the ALI
solution as a function of the parameters , and optical depth
variable .Comment: 7 pages, 11 figures, A&A, accepted 30 July 2003, minor correction
Analysis and design of a flat central finned-tube radiator
Computer program based on fixed conductance parameter yields minimum weight design. Second program employs variable conductance parameter and variable ratio of fin length to tube outside radius, and is used for radiator designs with geometric limitations. Major outputs of the two programs are given
Differential effects of food availability on minimum and maximum rates of metabolism
Metabolic rates reflect the energetic cost of living but exhibit remarkable variation among conspecifics, partly as a result of the constraints imposed by environmental conditions. Metabolic rates are sensitive to changes in temperature and oxygen availability, but effects of food availability, particularly on maximum metabolic rates, are not well understood. Here, we show in brown trout (Salmo trutta) that maximum metabolic rates are immutable but minimum metabolic rates increase as a positive function of food availability. As a result, aerobic scope (i.e. the capacity to elevate metabolism above baseline requirements) declines as food availability increases. These differential changes in metabolic rates likely have important consequences for how organisms partition available metabolic power to different functions under the constraints imposed by food availability
Analysis of low-temperature direct-condensing vapor-chamber fin and conducting fin radiators
Analysis of flat, direct-condensing finned-tube space radiator with vapor chamber, and central fin tube geometries for low temperature Rankine space power electric generating syste
Optical manipulation of Berry phase in a solid-state spin qubit
The phase relation between quantum states represents an essential resource
for the storage and processing of quantum information. While quantum phases are
commonly controlled dynamically by tuning energetic interactions, utilizing
geometric phases that accumulate during cyclic evolution may offer superior
robustness to noise. To date, demonstrations of geometric phase control in
solid-state systems rely on microwave fields that have limited spatial
resolution. Here, we demonstrate an all-optical method based on stimulated
Raman adiabatic passage to accumulate a geometric phase, the Berry phase, in an
individual nitrogen-vacancy (NV) center in diamond. Using diffraction-limited
laser light, we guide the NV center's spin along loops on the Bloch sphere to
enclose arbitrary Berry phase and characterize these trajectories through
time-resolved state tomography. We investigate the limits of this control due
to loss of adiabiaticity and decoherence, as well as its robustness to noise
intentionally introduced into the experimental control parameters, finding its
resilience to be independent of the amount of Berry phase enclosed. These
techniques set the foundation for optical geometric manipulation in future
implementations of photonic networks of solid state qubits linked and
controlled by light.Comment: 18 pages, 5 figure
Computer program for preliminary design and analysis of V/STOL tip-turbine fans
Computer program for design and analysis of V/STOL tip turbine fan
Evolução e controle da armilariose em pínus no Sul do Brasil.
O gênero Pinus tem ocupado a segunda maior área com florestas plantadas de espécies exóticas para produção de madeira no Brasil. As espécies comercialmente plantadas são consideradas bem adaptadas às condições de clima e solos brasileiros e dentre os fatores adversos ao seu cultivo encontram-se as doenças. A armilariose causada pelo fungo Armillaria sp. é a principal doença em pínus no Brasil e provoca o apodrecimento das raízes e do colo da árvore, resultando na morte do hospedeiro. A rizomorfas que disseminam-se de árvores doentes ou mortas ou de madeira colonizada pelo fungo através do solo são o principal veículo de disseminação desta doença. Este trabalho apresenta as informações mais atuais da armilariose em pínus na região Sul do Brasil, enfocando a etiologia, distribuição geográfica e o controle biológico.1 CD-ROM. Palestra (Doenças florestais). Co-promoção: Embrapa Florestas
Diplomats or Defendants? Defining the Future of Head-of-State Immunity
Fluorescence nanoscopy provides means to discernthe finer details of protein localization and interaction in cells by offeringan order of magnitude higher resolution than conventional optical imagingtechniques. However, these super resolution techniques put higher demands onthe optical system as well as on the fluorescent probes, making multicolorfluorescence nanoscopy a challenging task. Here we present a new and simpleprocedure which exploits the photostability and excitation spectra of dyes toincrease the number of simultaneous recordable targets in STED nanoscopy. Weuse this procedure to demonstrate four color STED imaging of platelets with ≤40 nm resolution and low crosstalk. Platelets can selectively store, sequesterand release a multitude of different proteins, and in a manner specific fordifferent physiological and disease states. By applying multicolor nanoscopy tostudy platelets, we can achieve spatial mapping of the protein organizationwith a high resolution, for multiple proteins at the same time and in the samecell. This provides a means to identify specific platelet activation states fordiagnostic purposes and to understand the underlying protein storage andrelease mechanisms. We studied the organization of the pro- and anti-angiogenicproteins VEGF and PF-4 together with fibrinogen and filamentous actin, andfound distinct features in their respective protein localization. Further,colocalization analysis revealed only minor overlap between the proteins VEGFand PF-4 indicating that they have separate storage and release mechanisms,corresponding well with their opposite rules as pro- and anti-angiogenicproteins, respectively.Updated from "Submitted" to "Published". QC 20140630</p
- …
