In Vitro Selection Of Dendrobium Sonia-28 Protocorm-Like Bodies Against Fusarium Proliferatum

Dendrobium sonia-28 adalah hibrid orkid yang penting dalam industri bunga di Malaysia kerana berkeupayaan berbunga berulang kali dan berbunga padat yang kini sedang menghadapi masalah pengeluaran yang serius akibat penyakit disebabkan kulat, terutamanya oleh Fusarium proliferatum. Untuk mengatasi masalah ini, salah satu strategi yang sedang diusahakan adalah dengan penghasilan orkid mutan baru. Mutagenesis secara in vitro dengan cara kultur turasan Fusarium proliferatum (CF), asid fusarik (FA) dan sinaran gama boleh digunakan untuk menghasilkan mutan yang lebih baik dari segi ekonomi. Dalam kajian ini, pemilihan jasad seperti protokom (JSP) yang bertoleransi terhadap F. proliferatum telah dijalankan dengan menilai kesan kepekatan CF (5-20%) dan FA (0.05-0.2 mM) dan pelbagai dos sinaran gama (10-200 Gy). Hasil kajian menunjukkan bahawa kadar hidup dan berat JSP berkadar songsang terhadap inokulasi dan sinaran dos. Selain itu, kadar kematian dan kekurangan berat JSP meningkat di kalangan JSP yang lebih kecil selepas rawatan CF dan FA. Keputusan menunjukkan bahawa ujian sensitiviti radio (LD50) bagi JSP lebih kurang pada 43 Gy. Dendrobium sonia-28 is an important orchid hybrid in Malaysian flower industry for its flowering recurrence and dense inflorescences which currently facing serious production problems due to fungal diseases, especially caused by Fusarium proliferatum. To overcome this impediment, one of the strategies being pursued is by the production of new orchid mutants. In vitro mutagenesis by means of Fusarium proliferatum culture filtrate (CF), fusaric acid (FA) and gamma irradiation can be used to produce economically improved mutants. In this study, selection of Fusarium proliferatum-tolerant protocorm-like bodies (PLBs) was carried out by assessing the effects of different concentrations of CF (5-20%) and FA (0.05-0.2 mM) and various doses of gamma irradiation (10-200 Gy). Results showed that PLBs survival rate and weight were inversely related to the inoculation and irradiation doses. Additionally, PLBs death and weight reducing increased among smaller PLBs after CF and FA treatments. Results indicated that the radio sensitivity test (LD50) for the PLBs was approximately at 43 Gy

An Exploratory Study of the Language-learning Style Preferences of Iranian EFL High School Students

This study explored the learning style preferences of 40 Iranian students at Marefat Iranian high school in Kuala Lumpur of which, 20 are females and 20 are males. To this end, this study used structured interview to elicit in-depth information from the students. The results of the study showed that learning style preferences of Iranian students were different according to their gender. Female students preferred auditory learning as their major learning style, while male students preferred kinesthetic more. Moreover, the findings revealed that Kinesthetic learning was the least preferred learning style of the most female students, whereas the least preferred learning style of male students was tactile learning. Keywords:  Learning Style Preferences, High School Students, Gender, EFL

The role of titanium on the microstructure and mechanical properties of additively manufactured C300 maraging steels

In this study, C300 metal powders containing two different Ti contents (0.72 and 1.17 wt%) were used to additively manufacture maraging steel samples in both horizontal and vertical directions via laser powder bed fusion (LPBF) technique. The effect of Ti addition on the microstructural and mechanical properties of the additively manufactured (AM) maraging steels was investigated using scanning, transmission electron microscopies (SEM, TEM), and electron backscatter diffraction (EBSD) along with uniaxial tensile and hardness testing procedures. Besides, X-ray diffraction (XRD) technique was employed to identify various phases formed during the LPBF process. The results showed that the horizontally printed Ti-rich samples exhibited higher retained austenite (γ) phase and superior values of hardness and tensile strength, while those ones vertically prepared showed an excellent ductility that could bring benefits in high-cycle fatigue applications. The TEM observations confirmed the presence of CoNi precipitates as well as high dislocation densities in the horizontal high Ti content samples, which are associated with higher strain hardening and tensile strength

Revealing the impact of Hot Isostatic Pressing temperature on the microstructure and mechanical characteristics of Selective Laser Melted CuAlNiMn shape memory alloy

The present research examines the impact of temperature during Hot Isostatic Pressing (HIP) on the mechanical, microstructure, and density characteristics of Cu-based shape memory alloys (SMAs) made by Selective Laser Melting (SLM). HIP improved the density of the built components by 11.5 %, with a reduction in density with an increase in HIP temperature. Pore aspect ratio analysis revealed non-spherical pores at higher temperatures, while spherical and small pores were observed at 950 °C. SEM analysis demonstrated the disappearance of shrinkage porosity and an increase in grain size with higher HIP temperatures. XRD analysis confirmed phase transformation and variation in crystallite size with an increase in HIP temperature. After HIP treatment, microhardness and tensile strength significantly improved, with the 950 °C sample showing the highest values

High strain rate torsional response of maraging steel parts produced by laser powder bed fusion techniques: Deformation behavior and constitutive model

The deformation performance of maraging steel samples fabricated using the laser powder bed fusion technique was evaluated using the split Hopkinson torsion bar (SHTB) test. Thin-walled tubular maraging steel samples were deformed under dynamic torsional loading at strain rates of 260 s−1 to 720 s−1 using twist angles varying from 3 to 12°. Microstructural and textural investigations were carried out on deformed samples using the electron backscatter diffraction technique and scanning electron microscopy. Results showed that maraging steel samples fractured when deformed using an angle of twist of 12° and strain rate of 650 s−1. As a result of deformation localization at high strain rates, adiabatic shear bands are developed in some thin-walled tubular torsion specimens deformed using the 12-degree angle of twist, leading to fracture. Textural studies showed that texture weakening occurred with an increment in strain rate ascribable to grain fragmentation. In this study, two models (empirically and semi-empirically) were employed for describing maraging steel performance during high strain-rate torsional loading. Simulation results based on Kobayashi-Odd and Nemat-Nasser models agreed well with the experimental data.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Jilt Sietsm

Microstructure and Corrosion Resistance of Composite nc-TiO2/Ni Coating on 316L Steel

The aim of this work was to obtain composite of nc-TiO2/Ni coatings on 316L steel and to characterize their corrosion resistance. In order to investigate the influence of the addition of TiO2 nanoparticles, both pure Ni and composite nc-TiO2/Ni coatings were electrodeposited from nickel citrate baths. The microstructure of the coatings was examined by scanning and transmission electron microscopy. The nc-TiO2/Ni coatings were about 10 μm thick. Their microstructure consisted of TiO2 nanoparticles uniformly distributed in nanocrystalline Ni matrix. The corrosion resistance of the coatings was measured using impedance spectroscopy and polarization curves techniques in Ringer’s solution. It was determined that the addition of nano-TiO2 particles improved corrosion resistance and reduced corrosion rate of the coated steel