On waveform analysis, the adaptive task technique, and the effect of vibration on manual control skill

A re-examination of fundamental concepts and a formal structuring of the waveform analysis problem is presented in Part I. eg. the nature of frequency is examined and a novel alternative to the classical methods of detection proposed and implemented which has the advantage of speed and independence from amplitude. Waveform analysis provides the link between Parts I and II. Part II is devoted to Human Factors and the Adaptive Task Technique. The Historical, Technical and Intellectual development of the technique is traced in a review which examines the evidence of its advantages relative to non-adaptive fixed task methods of training, skill assessment and man-machine optimisation. A second review examines research evidence on the effect of vibration on manual control ability. Findings are presented in terms of percentage increment or decrement in performance relative to performance without vibration in the range 0-0.6Rms'g'. Primary task performance was found to vary by as much as 90% between tasks at the same Rms'g'. Differences in task difficulty accounted for this difference. Within tasks vibration-added-difficulty accounted for the effects of vibration intensity. Secondary tasks were found to be largely insensitive to vibration except secondaries which involved fine manual adjustment of minor controls. Three experiments are reported next in which an adaptive technique was used to measure the % task difficulty added by vertical random and sinusoidal vibration to a 'Critical Compensatory Tracking task. At vibration intensities between 0 - 0.09 Rms 'g' it was found that random vibration added (24.5 x Rms'g')/7.4 x 100% to the difficulty of the control task. An equivalence relationship between Random and Sinusoidal vibration effects was established based upon added task difficulty. Waveform Analyses which were applied to the experimental data served to validate Phase Plane analysis and uncovered the development of a control and possibly a vibration isolation strategy. The submission ends with an appraisal of subjects mentioned in the thesis title.

一种宽带拉曼放大碲酸盐玻璃的拉曼散射特性

The flattening and broadening effects of Ga2O3, GeO2, P2O5 in TeO2-BaCO3-SrCO3- Nb2O5 (TBSN) glass system were studied. The results showed that P2O5 can broaden the vibration band in Raman spectra and Ga2O3, GeO2 can flatten the spectra compared with TBSN glass. And also, they can extend the main vibration band and decrease the vibration intensity of 730 cm^-1 and 780 cm^-1 nonbridging oxygen connected with Te. They also make for the decrease of flatness in 600-870 cm^-1 vibration band and GeO2 has larger effect than Ga2O3 in weakening the vibration of nonbridging oxygen.

Effect of apparent viscosity on fluidized bed drying process parameters of guava pulp

Pressure drop and minimum fluidization velocity were experimentally studied in a vibro-fluidized bed of inert particles subjected to different vibration intensities during drying of guava pulp. Maltodextrin was added to the pulp in order to prevent stickiness between particles and the consequent bed collapse. Pulps were initially concentrated, resulting in pastes with different soluble solids content, and a constant fraction of maltodextrin was guaranteed in the final pulp samples. The pulp rheological behavior as affected by temperature and total soluble solids content, including maltodextrin, was evaluated and the effect of pulp apparent viscosity on pressure drop and minimum vibro-fluidization velocity were investigated. Two types of inert particles -3.6 mm glass beads and 3 mm Teflon cylinders were tested and, due to lower pressure drop presented by Teflon cylinders during operation of the dry vibro-fluidized bed, these particles were adopted for pulp drying process. Increasing pulp apparent viscosity caused a considerable increase in the vibro-fluidized bed pressure drop during pulp drying and, as a consequence resulted in a larger value of minimum vibro-fluidization velocity. on the other hand, the negative effect of increasing apparent viscosity could be attenuated by increasing the fluidized bed vibration intensity, which could prevent stickiness between particles. (c) 2006 Elsevier Ltd. All rights reserved.

Effect of apparent viscosity on the pressure drop during fluidized bed drying of soursop pulp

Pressure drop and minimum fluidization velocity were experimentally studied in a vibro-fluidized bed of inert particles subjected to different vibration intensities during drying of soursop pulp. Maltodextrin was added to the pulp in order to prevent stickiness between particles and the consequent bed collapse. Pulps were initially concentrated, resulting in pastes with different soluble solids content, and a constant fraction of maltodextrin was guaranteed in the final pulp samples. The pulp theological behavior as affected by temperature and total soluble solids content, including maltodextrin, was evaluated and the effect of pulp apparent viscosity on pressure drop and minimum vibro-fluidization velocity were investigated. Two types of inert particles -3.6 mm glass beads and 3 mm Teflon cylinders (length and diameter) - were tested and, due to lower pressure drop presented by Teflon cylinders during operation of the dry vibro-fluidized bed, these particles were adopted for pulp drying process. Increasing pulp apparent viscosity caused a considerable increase in the vibro-fluidized bed pressure drop during pulp drying and, as a consequence resulted in a larger value of minimum vibro-fluidization velocity. on the other hand, the negative effect of increasing apparent viscosity could be attenuated by increasing the fluidized bed vibration intensity, which could prevent stickiness between particles. (c) 2006 Elsevier B.V. All rights reserved.

IR reflectance characterization of glass-ceramic films obtained by high pressure impregnation of SnO2 nanopowders on float glass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pelvic floor stimulation: what are the good vibrations?

OBJECTIVE: The aim of this study was to determine if two different whole body vibration, sinusoidal vibration (SV) and stochastic resonance vibration (SRV), using various intensities lead to a reactive activation of pelvic floor muscles. STUDY DESIGN: We compared the pelvic floor muscle response of a healthy control group with that of a post partum group with weakened pelvic floor contraction. Activation effects of stochastic resonance vibration and sinusoidal vibration with six increasing vibration intensities were investigated using pelvic floor EMG and compared to activity during rest and maximum voluntary contraction. RESULTS: Both whole body vibration systems were able to activate pelvic floor muscles significantly depending on vibration intensity. Generally, the SRV achieved a significantly higher activation than maximum voluntary contraction, especially in women post partum and using a frequency of 6-12 Hz. CONCLUSION: SRV, compared to SV, leads to higher pelvic floor muscle activation in subjects with weakened pelvic floor muscles and achieves higher pelvic floor activation than maximum voluntary contraction alone. Neurourol. Urodynam. 28:405-410, 2009. (c) 2009 Wiley-Liss, Inc.

Intensities in infrared bands V: Bond polar properties in dimethylacetylene

The absolute intensities of all except one of the infra-red fundamental vibration bands of dimethyl acetylene have been determined, and the results have been used to compute polar properties of the C—H and C—C bonds. It has been found that if the very probable assumption is made that the acetylenic carbon atoms carry a residual negative charge, the hydrogen atoms in the C—H bonds must carry a residual positive charge. The probable value of the C—H dipole is about 04 Debye, and that of the C—C bond about 1 Debye. Comparisons have been made with the results of similar work with related molecules.

Prediction and measurement of forced response of a composite blade undergoing nonlinear vibration

The main objective of this project is to experimentally demonstrate geometrical nonlinear phenomena due to large displacements during resonant vibration of composite materials and to explain the problem associated with fatigue prediction at resonant conditions. Three different composite blades to be tested were designed and manufactured, being their difference in the composite layup (i.e. unidirectional, cross-ply, and angle-ply layups). Manual envelope bagging technique is explained as applied to the actual manufacturing of the components; problems encountered and their solutions are detailed. Forced response tests of the first flexural, first torsional, and second flexural modes were performed by means of a uniquely contactless excitation system which induced vibration by using a pulsed airflow. Vibration intensity was acquired by means of Polytec LDV system. The first flexural mode is found to be completely linear irrespective of the vibration amplitude. The first torsional mode exhibits a general nonlinear softening behaviour which is interestingly coupled with a hardening behaviour for the unidirectional layup. The second flexural mode has a hardening nonlinear behaviour for either the unidirectional and angle-ply blade, whereas it is slightly softening for the cross-ply layup. By using the same equipment as that used for forced response analyses, free decay tests were performed at different airflow intensities. Discrete Fourier Trasform over the entire decay and Sliding DFT were computed so as to visualise the presence of nonlinear superharmonics in the decay signal and when they were damped out from the vibration over the decay time. Linear modes exhibit an exponential decay, while nonlinearities are associated with a dry-friction damping phenomenon which tends to increase with increasing amplitude. Damping ratio is derived from logarithmic decrement for the exponential branch of the decay.