1,802 research outputs found
Evaluation of a load cell model for dynamic calibration of the rotor systems research aircraft
The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission system from the fuselage. An analytical model of the relationship between applied rotor loads and the resulting load cell measurements is derived by applying a force-and-moment balance to the isolated rotor/transmission system. The model is then used to estimate the applied loads from measured load cell data, as obtained from a ground-based shake test. Using nominal design values for the parameters, the estimation errors, for the case of lateral forcing, were shown to be on the order of the sensor measurement noise in all but the roll axis. An unmodeled external load appears to be the source of the error in this axis
Mechanism of membrane tube formation induced by adhesive nanocomponents
We report numerical simulations of membrane tubulation driven by large
colloidal particles. Using Monte Carlo simulations we study how the process
depends on particle size, concentration and binding strength, and present
accurate free energy calculations to sort out how tube formation compares with
the competing budding process. We find that tube formation is a result of the
collective behavior of the particles adhering on the surface, and it occurs for
binding strengths that are smaller than those required for budding. We also
find that long linear aggregates of particles forming on the membrane surface
act as nucleation seeds for tubulation by lowering the free energy barrier
associated to the process
Non-interferometric Test of Collapse Models in Optomechanical Systems
The test of modifications to quantum mechanics aimed at identifying the
fundamental reasons behind the un-observability of quantum mechanical
superpositions at the macro-scale is a crucial goal of modern quantum
mechanics. Within the context of collapse models, current proposals based on
interferometric techniques for their falsification are far from the
experimental state-of-the-art. Here we discuss an alternative approach to the
testing of quantum collapse models that, by bypassing the need for the
preparation of quantum superposition states might help us addressing non-linear
stochastic mechanisms such as the one at the basis of the continuous
spontaneous localisation model.Comment: 6 pages, accepted for publication in Phys. Rev. Lett.
Distribution system simulator
In a series of tests performed under the Department of Energy auspices, power line carrier propagation was observed to be anomalous under certain circumstances. To investigate the cause, a distribution system simulator was constructed. The simulator was a physical simulator that accurately represented the distribution system from below power frequency to above 50 kHz. Effects such as phase-to-phase coupling and skin effect were modeled. Construction details of the simulator, and experimental results from its use are presented
A sham-controlled trial of acupressure on the quality of sleep and life in haemodialysis patients
Background Sleep disorder in haemodialysis patients can lead to disturbance in their psychosocial function and interpersonal relations, and reduced quality of life. The aim of the present study was to investigate the effect of acupressure on the quality of sleep of haemodialysis patients. Methods In a randomised controlled trial, 108 haemodialysis patients were randomly divided into three groups: true acupressure, placebo acupressure, and no treatment. The two acupressure groups received treatment three times a week for 4 weeks during dialysis. Routine care only was provided for the no treatment group. The main study outcome was sleep quality. Results The total Pittsburgh Sleep Quality Index score decreased significantly from 11.9±3.13 to 6.2±1.93 in the true acupressure group, from 11.3±3.69 to 10.6±3.82 in the sham acupressure group, and from 10.9±4.10 to 10.7±3.94 in the no treatment group. There was a significant difference between groups (p<0.001). Conclusions Acupressure seems to have a positive effect on the sleep quality in haemodialysis patients. Clinical trial registration IRCT201106145864N2
Effect of modulus and dosage of waterglass on early age shrinkage of sodium silicate activated slag paste
In recent years, alkali-activated slag (AAS) as an alternative low-carbon emission
and high strength cementitious material has received increased attention. However, high shrinkage
and crack tendency of AAS limit its wider industrial applications. Although considerable
researches have already been carried out on Portland cement (PC) based systems, the information
and understanding on the early age shrinkage of AAS is still limited. On the other hand, early age
shrinkage occurs mainly due to a high rate of water evaporation from the surface of fresh concrete.
Therefore, this study seeks to explore the potential of two sodium silicate activated slag mixtures
variables, namely, waterglass moduli and activator content, on moisture loss and early age
shrinkage properties of AAS. A control AAS mix was formulated with water glass (silica modulus
of 1.5) as an activator at the dosage of 4% (Na2O equivalent) by mass of slag and fixed waterbinder
ratio (w/b) of 0.4. Two mixtures with modulus of 0.75 and activator dosage of 6% were
compared in this study. The most significant findings to emerge from this study is that, AAS paste
with moduli of 0.75 and activator content of 4% showed lower amount of early age shrinkage.
However, further study still needs to be carried out in order to establish a better understanding of
the current results
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