Replacing of glass fibres with seed oil palm fibres for tribopolymeric composites

In the current study, the possibility of replacing woven glass fibres (WGFs) with seed oil palm fibres (SOPFs) as reinforcements for tribopolymeric composites is investigated. Mainly, two different polyester composites based on woven glass reinforced polyester (WGRP) and seed oil palm reinforced polyester (SOPRP) are developed. Different volume fractions (25, 35, and 45 vol.- %) of SOPFs were considered. The experiments were performed using a block on disc (BOD) machine and the tests were conducted under dry contact condition against smooth stainless steel counterface at 2?8 m s21 sliding velocity, 20 N applied load for different sliding distances (up to 5 km). The wear mechanism was categorised using a Scanning Electron Microscope (SEM). The results revealed that the steady state was reached after 4 km sliding distance for both WGRP and SOPRP composites. Seed oil palm reinforced polyester composites showed very high friction coefficient compared to WGRP. 35 vol.-% SOPRP composite exhibited a promising wear result, i.e. SOPFs are possible to replace WGFs in polymeric composites reinforcements whereas the wear resistance of the synthetic and natural composite were almost the same. The wear mechanisms for SOPRP composites were predominated by microcracks, deformation and pulled out of fibres while in the WGRP composite, abrasive nature was observed

The effect of pedunculopontine nucleus deep brain stimulation on postural sway and vestibular perception

© 2016 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of Europe an Academy of Neurology. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and re production in any medium, provided the original work is properly cited, see https://creativecommons.org/licenses/by/3.0/BACKGROUND AND PURPOSE: Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) reduces the number of falls in patients with Parkinson's disease (PD). It was hypothesized that enhanced sensory processing contributes to this PPN-mediated gait improvement. METHODS: Four PD patients (and eight matched controls) with implanted bilateral PPN and subthalamic nucleus DBS electrodes were assessed on postural (with/without vision) and vestibular perceptual threshold tasks. RESULTS: Pedunculopontine nucleus ON stimulation (compared to OFF) lowered vestibular perceptual thresholds but there was a disproportionate increase in the normal sway increase on going from light to dark. CONCLUSIONS: The disproportionate increased sway with PPN stimulation in the dark may paradoxically improve balance function since mechanoreceptor signals rapidly adapt to continuous pressure stimulation from postural akinesia. Additionally, the PPN-mediated vestibular signal enhancement also improves the monitoring of postural sway. Overall, PPN stimulation may improve sensory feedback and hence balance performance.Peer reviewedFinal Published versio

Multiphoton radiative recombination of electron assisted by laser field

In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons represents an equidistant pattern with the spacing equal to the laser frequency. The distribution of intensities in this spectrum is studied employing the Keldysh-type approximation, i.e. neglecting interaction of the impact electron with the atomic core in the initial continuum state. Within the adiabatic approximation the scale of emitted photon frequencies is subdivided into classically allowed and classically forbidden domains. The highest intensities correspond to emission frequencies close to the edges of classically allowed domain. The total cross section of electron recombination summed over all emitted photon channels exhibits negligible dependence on the laser field intensity.Comment: 14 pages, 5 figures (Figs.2-5 have "a" and "b" parts), Phys.Rev.A accepted for publication. Fig.2b is presented correctl

ASIATRIB 2010: Frontiers in Tribology - Knowledge and Friendship

[Introduction]: Recently, there are wide researches on the possibility of using natural fibres as reinforcement for polymeric composites. One of the most promising natural fibres is kenaf fibre, which has high interfacial adhesion with synthetic matrix, and great specific tensile modulus [1]. Few attempts have been made to study the effect of oil palm, coir, or betelnut fibres [2, 3], on tribological characteristics of polyester composites. In those works, the composites exhibited very poor wear performance. due to the poor interfacial adhesion of the fibres with the matrix leading to pulling out of the fibres during the sliding. In the current work, the effect of high interfacial adhesion kenaf fibre on the abrasive wear performance of epoxy composite was studied under abrasive loading conditions. The worn surfaces were examined using SEM

Potential use of drone ultra-high-definition videos for detailed 3D city modeling

Ongoing developments in video resolution either using consumer-grade or professional cameras has opened opportunities for different applications such as in sports events broadcasting and digital cinematography. In the field of geoinformation science and photogrammetry, image-based 3D city modeling is expected to benefit from this technology development. Highly detailed 3D point clouds with low noise are expected to be produced when using ultra high definition UHD videos (e.g., 4K, 8K). Furthermore, a greater benefit is expected when the UHD videos are captured from the air by consumer-grade or professional drones. To the best of our knowledge, no studies have been published to quantify the expected outputs when using UHD cameras in terms of 3D modeling and point cloud density. In this paper, a quantification is shown about the expected point clouds and orthophotos qualities when using UHD videos from consumer-grade drones and a review of which applications they can be applied in. The results show that an improvement in 3D models of ≅65% relative accuracy and ≅90% in point density can be attained when using 8K video frames compared with HD video frames which will open a wide range of applications and business cases in the near future

2nd International Conference on Advanced Tribology (iCAT 2008)

[Abstract]: This paper presents an attempt to use kenaf fibres as a reinforcement for tribo-polyester composite for bearing applications. Kenaf fibres reinforced epoxy (KFRE) composites were fabricated using a closed mould technique associated with vacuum system. Adhesive wear and frictional behaviour of the composites were studied against polished stainless steel counterface using Block-On-Disc (BOD) machine at different applied loads (10-100N), sliding distances (0-5km) and sliding velocities (1.1-3.9m/s). Furthermore, the effect of the fibre orientations, with respect to the sliding direction, were considered, i.e. Parallel (P-O), Anti-Parallel (AP-O) and Normal (NO). The morphology of the worn surfaces of the composites was studied using a scanning electron microscope (SEM). The result revealed that the presence of kenaf fibres in the composite enhanced the wear and frictional performance of the epoxy. Applied load and sliding velocity have less effect on the specific wear rate of the composite in all the three orientations. The composite exhibited better wear performance in P-O and AP-O compared to N-O

Charged domain walls as quantum strings living on a lattice

A generic lattice cut-off model is introduced describing the quantum meandering of a single cuprate stripe. The fixed point dynamics is derived, showing besides free string behavior a variety of partially quantum disordered phases, bearing relationships both with quantum spin-chains and surface statistical physics.Comment: 22 page, 17 figure

23rd Annual Conference of the Australasian Association for Engineering Education (AAEE 2012)

The Engineering Materials course is one of the common subjects for first year engineering students and provided the ideal opportunity for this study due to the large class size and the presence of certain traditionally complex concepts. Based on the data collected by four international universities, most engineering students face problems in understanding complex topics in the Engineering Materials course, for example, atomic bonds, the binary phase diagram, and the microstructure of materials. It is argued here that introducing multimedia resources and visualization tools such as animations, videos, photos, inking and sketching in teaching could enhance students' understanding of both threshold concepts and complex knowledge