Accommodating Learners With Dyslexia in English Language Teaching in Sri Lanka : teachers' knowledge, attitudes and challenges

As it is estimated that 10% of the world population has dyslexia or related learning difficulties, it is vital for language teachers to have a thorough understanding of such difficulties and of inclusive teaching techniques. It is believed that teacher training can increase teachers’ knowledge of dyslexia and inclusion, inculcate positive attitudes among them on inclusion and increase their self-efficacy beliefs. The study discussed in this paper analysed if a teacher training programme aimed at a group of ELT professionals in Sri Lanka could do the same and also the challenges that they would face in introducing inclusive practices into their context. A questionnaire and interview data revealed that the teacher training programme was able to change teachers’ negative attitudes towards dyslexia, increase their knowledge of dyslexia and inclusive practices and increase their readiness to implement inclusive classroom techniques. The findings also revealed that institutional barriers such as a rigid examination system and lack of flexibility in the curriculum may hinder how inclusive practices are implemented. In addition, negative socio-cultural ideology and some practical classroom problems may also affect implementation

Porous micro/nano structured oxidic titanium surface decorated with silicon monoxide

Novel types of titanium oxidic surfaces were fabricated by a shifted Laser Surface Texturing of titanium in air, producing porous micro/nanostructured topography, and by a subsequent Nd:YAG laser-induced reactive deposition of Ti5Si3 titanium silicide in vacuum, coating this topography with scattered sub-micron particles of silicon monoxide. Both surfaces are characterized by XRD, electron microscopy and FTIR, Raman and X-ray photoelectron spectroscopy and the second laser-induced process is inferred to involve a yet unreported redox path between Ti5Si3 (Si) and oxidized titanium surface. Both pristine and SiO-modified laser-structured surfaces were examined for the response of human SCP-1 and murine MC3T3 cells and found biocompatible in terms of cell survival, proliferation and cell morphology. The combined use of two different lasers may encourage further research on the development of new micro/nanostructured titanium surfaces enriched with nanosized entities

Vývoj radiačního poškození v čistém W a slitině W-Cr-Hf způsobené 5 MeV Au ionty v širokém rozsahu dpa

Čistý W a slitina W-Cr-Hf, které jsou perspektivními materiály pro jaderné fúzní reaktory, jako je DEMO, byly ozářeny při pokojové teplotě 5 MeV ionty Au2+ s dávkami mezi 4 × 10e14 a 1,3 × 10e16 ionty.cm-2 za účelem vytvoření různých úrovní poškození mřížky od jednotek až po desítky dpa. Odlišný charakter akumulace radiačního poškození, mikrostruktura a povaha defektů byly pozorovány u čistého W i slitin W-Cr-Hf, přičemž tyto slitiny vykazovaly zajímavou schopnost reorganizace poškození a snížení velikosti defektu při vyšších dávkách iontů, jak bylo stanoveno pozitronovou anihilační spektroskopií. (PAS). Vysoká míra radiačního poškození v ozařované vrstvě byla prokázána ve vzorcích W již při nižších dávkách Au-iontů ve srovnání se vzorky W-Cr-Hf, kde se poškození stupňovitě zvyšovalo s rostoucí dávkou Auiontů. Zřetelná akumulace defektů byla doprovázena odlišnou distribucí implantovaných Au-iontů v ozařované vrstvě stanovenou sekundární iontovou hmotnostní spektrometrií (SIMS), stejně jako tepelné vlastnosti ukázaly následné zhoršení hloubky v dobré shodě s Au koncentračními hloubkovými profily. TEM potvrdila výše uvedená zjištění, kde podpovrchová vrstva vykazovala po ozáření uvolnění defektů, maximum hustoty dislokační smyčky bylo identifikováno v hloubce podle predikovaného maxima dpa (posun částic na atom) pro nižší dávku Au-iontů. Kromě toho TEM ukazuje, že struktura pásu hustoty dislokací se objevila ve vzorcích W-Cr-Hf vykazujících pásmo defektů s vysokou hustotou podle projektovaného rozsahu Au-iontů současně s další vrstvou s většími izolovanými dislokacemi vyjádřenými ve větší hloubce jako rostoucí funkce dávky Au-iontů. Takový jev nebyl u W vzorků pozorován.Pure W and W-Cr-Hf alloy which are prospective materials for nuclear fusion reactors, such as DEMO, were irradiated at room temperature with 5 MeV Au2+ ions with fluences between 4 × 10e14 and 1.3 × 10e16 ions.cm-2 to generate various levels of lattice damage from about units up to tens of dpa. The distinct character of radiation damage accumulation, microstructure and defect nature have been observed in both pure W and W-Cr-Hf alloys, the latter exhibited interesting ability of damage reorganisation and defect size decrease at the higher ion fluences as determined by positron annihilation spectroscopy (PAS). High radiation damage rate in the irradiated layer has been evidenced in the W samples already at the lower Au-ion fluences compared to W-Cr-Hf samples, where the damage increased in steps with the increasing Au-ion fluence. The distinct defect accumulation was accompanied with the different Au-ion implanted distribution in the irradiated layer determined by Secondary Ion Mass Spectrometry (SIMS) as well as the thermal properties have shown the consequent worsening in the depth in good agreement with the Au-depth concentration profiles. TEM corroborated above mentioned findings, where the sub-surface layer exhibited defect release after the irradiation, the maximum of dislocation loop density has been identified in the depth according the predicted dpa (displacement particles per atom) maximum for the lower Au-ion fluences. Moreover, TEM shows the dislocation density band structure appeared in W-Cr-Hf samples exhibiting the high density defect band according the projected range of the Au-ions simultaneously with the additional layer with larger isolated dislocations pronounced in the higher depth as a growing function of Au-ion fluence. Such phenomenon was not observed in W samples

Radiation damage evolution in High Entropy Alloys (HEAs) caused by 3–5 MeV Au and 5 MeV Cu ions in a broad range of dpa in connection to mechanical properties and internal morphology

High Entropy Alloys (HEAs) are prospective materials for nuclear fusion reactors and were irradiated in this study at a broad range of energetic ion fluences. Different ion masses (Cu and Au ions) and energies (3 and 5 MeV) were selected to investigate dpa (displacement per atom) development, radiation defect accumulation based on prevailing collision processes (Au ions) and ionization processes (Cu ions) in various HEAs. The studied HEAs differ in terms of elemental composition, internal morphology (grain structure) and other modifiers. Dpa values of 1 to ∼66 were achieved at Cu and Au ion fluences from 4 × 1014 to 1.3 × 1016 ions.cm−2 at room temperature, which generated varying levels of lattice damage. Theoretical simulations were performed to estimate the energy stopping and dpa depth distribution using SRIM code and compared with Au-concentration depth profiles determined by Rutherford backscattering spectrometry for Au-ions with 3 MeV ion energy. The prevailing energy losses of ions via ionization processes for Cu-5 MeV ions were found to increase the damage through lattice strain and probable lattice distortion, although the main defect introduction is expected to occur via collisions during nuclear stopping. Structural modification and defect accumulation were investigated by positron annihilation spectroscopy (PAS), which revealed a broader damaged layer with defects, where HEA-Nb (NbCrFeMnNi) exhibited the least damage accumulation from chosen alloys with no strong relation to the Au-5 MeV ion implantation fluence, whereas strong defect accumulation was recorded in the Au-ion implanted Eurofer97 used for comparison and HEA-Co (CoCrFeMnNi). PAS analysis also allowed defect sizes to be determined as an additional structural characteristic. The observed trends were also confirmed by thermal property analysis, with a worsening of thermal effusivity recorded after the irradiation in HEA-Co and Eurofer97. The worsening of the thermal properties was confirmed by the layer thickness, where the layer identified by PAS was found to be broader than the SRIM theoretical predictions. Nanoindentation measurements confirmed less pronounced radiation hardening of HEA-Nb relative to that observed in HEA-Co and Eurofer97. Transmission Electron Microscopy (TEM) analysis revealed layer thicknesses in reasonable agreement with the dpa depth profiles. The thermal effusivity decreased in the surface-irradiated layer in all investigated samples, the least influenced material was HEA-Nb