The effects of debate competition on critical thinking among Malaysian second language learners

Debate is a common co-curricular activity involving most Malaysian schools at the district level. Every year, each school would send three students to represent its team. In this study, forty (40) second language learners, aged 16 years old, were involved in a two hour debate activity carried out three days per week for three consecutive weeks. This activity was organized by their school seniors, aged 18 years, as part of their English assignment. A pre-post critical thinking test was carried out among the debaters and at the end of the activity, a survey was undertaken to gauge their perception of the thinking process they had experienced. The result revealed that there was a significant difference in their critical thinking skills before and after the debate activity as the intervention. The survey and teacher observation offered feedback on how debate foster their critical thinking. Among others, it showed the importance of scaffolding and collaborative learning in enhancing critical thinking. Another factor is the fact that debate involves argumentation, reasoning, explanation and questioning, all important critical thinking skills. Key words:Critical thinking Debate competition Second language learners Argumentation Explanation skill Reasoning skill Questioning skill Scaffolding collaborative thinkin

Kappa antagonist to prevent drug relapse: does stage in addiction cycle matter?

Introduction: An upregulation of the kappa opioid receptor (KOR) system during preoccupation stage in addiction cycle will cause dysphoria among addicts which can lead to relapse. Therefore, KOR antagonism might hold the key to prevent relapse. In this study, we aim to identify the exact addiction's stage in which KOR antagonist can be given. Methods: Using a conditioned place preference (CPP) model, adult Swiss albino mice were divided into two major groups. The first group received treatment at the initial stage of morphine withdrawal (7.5 mg/kg. i.p) while the second group received treatment after complete abstinence was achieved. Each major groups were further divided into two treatment groups (n=8-12), either received a functional KOR antagonist (0.3 mg/kg buprenorphine/ 1mg/kg naltrexone combination, i.p) or a selective KOR antagonist (10 mg/kg nor-BNI, i.p) prior to morphine priming (2.5 mg/kg, i.p). All data were analyzed using paired sample t-test. Results: The results showed that relapse was successfully attenuated in the groups that received KOR antagonists only after complete abstinence was successfully achieved (not significantly different from their baseline). However, the mice developed unusual sign of behavior sensitization (intermittent freezing, licking) when buprenorphine/naltrexone combination was given at initial stage of withdrawal. Conclusion: Our initial findings suggest that KOR antagonism might be beneficial only after the addicts achieved complete abstinence to prevent future drug-induced relapse. Brain study should be conducted to explain the unusual behavior seen when the drug intervention is given at an earlier stage of withdrawal

Highly stable graphene-assisted tunable dual-wavelength erbium-doped fiber laser

A highly stable tunable dual-wavelength fiber laser (TDWFL) using graphene as a means to generate a highly stable output is proposed and generated. The TDWFL comprises a 1 m long, highly doped erbiumdoped fiber (EDF) acting as the linear gain medium, with a 24-channel arrayed waveguide grating acting as a wavelength slicer as well as a tuning mechanism to generate different wavelength pairs. The tuned wavelength pairs can range from 0.8 to 18.2 nm. A few layers of graphene are incorporated into the laser cavity to induce the four-wave-mixing effect, which stabilizes the dual-wavelength output by suppressing the mode competition that arises as a result of homogenous broadening in the EDF. © 2013 Optical Society of Americ

Effect Of Bio-Based Lubricant Towards Emissions And Engine Breakdown Due To Spark Plug Fouling In A Two-Stroke Engine

Two-stroke also known as two-cycle gasoline engine is a spark ignition engine. Its uniqueness to the four-stroke engine is that this engine does not require lubricant sump, which makes construction lightweight and simple. Its lubricant is mixed with gasoline and burnt together during combustion. There are reports which stated that higher spark plug fouling is due to carbon deposition on the spark plug electrodes on a two-stroke engine when compared to the four-stroke. While many factors could have affected this situation, however, in this paper, the effect of mineral and bio-based lubricants towards carbon deposition and emissions are studied and reported. Idle, half and full throttle operation modes had been conducted on a two-stroke, 43 cubic centimeter engine. To keep combustion temperature below self-cleaning temperature on all three modes of operation, a zero-load test was utilized. This situation accelerates the deposition process as low temperature causes incomplete combustion. This could lead to the accumulation of char, unburned fuel, as well as condensed water and acids as the byproducts blanket the spark plug electrodes and the exhaust system. Five samples had been prepared with a commercially available mineral lubricant (T0) as reference. Trimethylolpropane Trioleate, TMPTO derived from plant origin was used as the bio-based candidate. It was then mixed with T0 which created another four lubricant samples namely T10, T15, T20 and T50 with 10%, 15%, 20% and 50% TMPTO accordingly. Results show that mineral lubricant T0 delivers the lowest hydrocarbon HC, carbon monoxide CO and smoke opacity during idle and half throttle operations. However, it exhibits a greasy deposit on the spark plug circumference and dry carbon deposits on its insulator tip. T0 also emits a liquid residue at the exhaust manifold. T10 and T50 show a wet deposit blanketing both electrodes. Severe deposition was recorded by T50 that caused the engine to fail half way with its emissions had the worst recording. T15 and T20 exhibit only dry carbon deposition on the spark plug circumference. However, T20 has outperformed T15 in terms of emissions with lower CO and CO2 emissions during idling and half-throttling. With better emissions than T15 and better carbon deposition than mineral (T0), T20 could be proposed to be used as a commercial two-stroke lubricant

Tribological improvement using ionic liquids as additives in synthetic and bio-based lubricants for steel-steel contacts

This study investigates the performance of three ionic liquids (ILs), trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate, trihexyl(tetradecyl)phosphonium decanoate, and 1-butyl-3-methylimidazolium tetrafluoroborate, as lubricant additives in synthetic oil polyalphaolefin (PAO8) and bio-based oil trimethylolpropane trioleate (TMPTO). The ILs were added at 0.5, 1.0, and 1.5 wt% concentrations and evaluated in terms of their miscibility with base oils as well as friction- and wear-reducing abilities. Four-ball and high-frequency reciprocating rig (HFRR) tribotesters were employed to evaluate the tribological performance under a boundary lubrication regime. Worn steel surfaces were characterized using optical microscopy, profilometry, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. The results suggested that the addition of trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate and trihexyl(tetradecyl)phosphonium decanoate improved the tribological performance of both PAO8 and TMPTO at an optimum concentration of 1 wt%. They showed good friction reduction, lower overall surface wear, and improved surface finishing. 1-Butyl-3-methylimidazolium tetrafluoroborate managed to improve the tribological performance of both base oils only at 0.5 wt%. A further increase in 1-butyl-3-methylimidazolium tetrafluoroborate concentration caused detrimental effects on the steel surface due to the formation of halogenic compounds

Sustainability of palm biodiesel in transportation: a review on biofuel standard, policy and international collaboration between Malaysia and Colombia

Biodiesel is gaining prominence as a superior alternative source of energy to replace petroleum-based fuel in transportation. As of today, the biodiesel market continuous to rise up as the biofuel has been introduced to more than 60 countries worldwide. The aim of the present review is to highlight on the scenario of the biofuel implementation in transportation sector towards sustainable development in Colombia and Malaysia. Colombia serves as an ideal comparative case for Malaysia in terms of biodiesel development since the country is the main palm oil producer in Latin America region and the pioneer in bioethanol industry. The first section shows an overview on the biodiesel as an alternative fuel in transportation. The next section will focus on a comparative study between Malaysia and Colombia biodiesel sector in terms of energy supply, resource, production and consumption, standards, techno-economic cost and their biodiesel policies. A comprehensive review was studied to discuss on the sustainability of palm cultivation and biodiesel, impact of palm industry and biodiesel policy in transportation sector and potential international collaboration between Malaysia and Colombia to improve their existing policies, strategies and blueprints related to the palm biodiesel industry, thus overcoming the challenges when dealing with global energy issue

Terahertz time-domain spectroscopy of local cow’s tissues

This study demonstrates terahertz time-domain spectroscopy characterization of animal tissues obtained from local cow at mart. Terahertz radiation is highly sensitive to the polar molecules of water, thus biological tissues with high level of hydration show strong absorption at terahertz frequencies. All tissue samples are desiccated at same temperature and time scale. The different frequency-dependent response to the terahertz radiation due to the water content are observed from the experimental data of the fat, muscle and mixed of both tissues

1500-nm Q-switched fibre laser with carbon nanotubes

A Q-switched fibre laser operating at 1500 nm is proposed and demonstrated. The laser uses a saturable absorber (SA) based on carbon nanotubes (CNTs) to generate Q-switched pulses, while a 30-m-long depressed-cladding erbium-doped fibre (DC-EDF) provides the necessary gain in the desired wavelength region. The proposed laser has lasing and pulsed thresholds of 30 mW and 50 mW respectively, along with a maximum output power, pulse energy and peak power of 0.5 mW, 7.6 nJ and 2.2 mW. Additionally, the output of the system also has a maximum repetition rate of 59.4 kHz with the shortest pulse duration measured at 3.4 ms. The output pulses are smooth and uniform, with no indication of self mode-locking

Graphene-Based Mode-Locked Spectrum-Tunable Fiber Laser Using Mach–Zehnder Filter

An ultrafast spectrum-tunable fiber laser using a tunable Mach-Zehnder filter (TMZF) and a graphene-based saturable absorber as a mode-locking element is proposed and demonstrated. The proposed laser uses a 2-m-long zirconia-erbium-doped fiber (Zr-EDF) as the primary gain medium. The Zr-EDF has a dopant concentration of 3800 ppm/wt and an absorption rate of 18.3 dB/m at 980 nm. The proposed laser is able to generate mode-locked solitons, with the central wavelength of the spectrum tunable from 1551 to 1570 nm and covering a wavelength range of about 19 nm. Sidebands are observed with 3-dB bandwidths and pulsewidths of between 3.4 and 3.6 nm and from 730 to 780 fs, respectively, as well as a time-bandwidth product between 0.32 and 0.33. The generated pulse yields an average output power value of ~ 1.4 mW, pulse energy of ~ 128 pJ, and repetition rate of ~ 10.9 MHz. This is the first time, to the knowledge of the authors, that a graphene-based mode-locked spectrum-tunable fiber laser is demonstrated using a TMZF

Q-switched pulse generation from an all-fiber distributed Bragg reflector laser using graphene as saturable absorber

A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and Faraday rotator mirror as end mirrors, together with a highly doped erbium-doped fiber as a gain source. The laser has a Q-switched threshold of about 28 mW and a tunable repetition rate of 10.4-18.0 kHz with varying pump power. The shortest pulse width obtained from the system is 3.7 μs, with a maximum pulse energy and peak power of 22.2 nJ and 3.4 mW, respectively