Formation of Fe-Ni composite on pure aluminum substrate by laser surface alloying

Aluminum is recently attracted the attention of several researchers due to its unique properties; however, it has low hardness, corrosion and mechanical properties. The technique of Laser surface alloying of aluminum substrate with nickel and iron under various processing conditions has been studied. In this paper, a low power CO2 laser was used to alloy pure aluminum substrates with Fe-Ni mixture of various exposures between 10-60 s. It indicates that the laser surface alloying technique using mixed powder with a ratio of 66.67%Ni–33.34%Fe can considerably enhance the hardness of aluminum surface. Microstructures of alloyed layers were studied by scanning electron microscope, optical microscope and the phases were identified by X-ray diffraction analysis. In addition, the micro-hardness of the surface alloyed layer was measured. The hardness was increased from 27 HV0.1 for untreated surface to as high as 53.9 HV0.1 for treating surface due to the formation Al6Fe, Al5Fe2, AlFe3, Al5FeNi, Al0.9Ni1.1 and Al76.8Fe14

Enhancement of hydrogen by laser focusing during plasma electrolysis of water

With the increasing energy costs and shortage of oil reserves, production and supply, the need of new energy sources becoming popular in recent days. In concern with global warming and climate change by emission of carbon dioxide with fossil fuel particularly coal has increased the importance of hydrogen. The Production and the enhancement of hydrogen on large scale is a goal towards the revolution of green and cheap energy. Photo catalysis and electrolysis of water are the important methods for production of hydrogen from water. In this paper the role of electrolyte as a photo catalyst was studied during electrolysis of water. The Production and the enhancement of hydrogen from the water have been investigated under the action of diode pumped solid state laser with second harmonic of wavelength 808nm. The efficiency of the hydrogen and oxygen yields was found to be greater than the normal Faradic efficiency. The parametric dependence of the yields as a function of laser beam power, irradiation time is shown. Laser focusing effect and parameters of the electrolysis fundamentals were carefully studied

Plasma splashing from Al and Cu materials induced by and Nd : YAG pulsed laser

Plasma splashing from Al and Cu target materials and the growth of thin films on Cu and Al, respectively, has been studied using a Q-switched Nd:YAG laser with a 1064-nm, 80-mJ, 8-ns pulse width as the source of ablation. The target kept rotating and the substrate, Cu for Al and vice versa, was placed at an angle of 15° with respect to the beam axis. During the laser-matter interaction, the targets absorbed thermal energy within the thermal region depth of 4.7 (1.1) nm, yielding an ablated skin depth of 6.7 (4.2) nm. The surface morphology of the exposed targets was studied by analyzing SEM micrographs obtained using a ZEISS SUPRA 35 VP. The obtained results are explained on the basis of different sputtering/ablation mechanisms. Comparatively severe damage forming a bigger crater is seen on the Al target surface in contrast to the crater on the Cu surface. This observation is correlated with the blustering effect and/or debris formation. Energy dispersive spectroscopy (EDX) of the substrates yielded the deposition of micrometric grain-size particle

Effect of etching time on optical and morphological features of N-type porous silicon prepared by photo-electrochemical method

Achieving efficient visible photoluminescence from porous-silicon (PSi) is demanding for optoelectronic and solar cells applications. Improving the absorption and emission features of PSi is challenging. Photo-electro-chemical etching assisted formation of PSi layers on n-type (111) silicon (Si) wafers is reported. Samples are prepared at constant current density (~30 mA/cm2) under varying etching times of 10, 15, 20, 25, and 30 min. The influence of etching time duration on the growth morphology and spectral properties are inspected. Room temperature photoluminescence (PL) measurement is performed to determine the optical properties of as-synthesized samples. Sample morphologies are imaged via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The thickness and porosity of the prepared samples are estimated using the gravimetric method. The emission and absorption data is further used to determine the samples band gap and electronic structure properties. Results and analyzed, interpreted with different mechanisms and compared

Dermal exposure to the herbicide-paraquat results in genotoxic and cytotoxic damage to germ cells in the male rat

The effects of exposure to low doses of paraquat, a herbicide, via the dermal route were studied on the spermatozoa of Sprague-Dawley rats. Paraquat (1, 1&#8217;-dimethyl-4, 4&#8217;-bipyridinium dichloride) was administered once a day for five days, at intervals of 24 h at 0, 6, 15 and 30 mg/kg, and the rats were sacrificed on days 7, 14, 28, and 42 after the last exposure. The sperm suspensions were obtained by mincing the caudae epididymes and ductus deferens for the purpose of performing a sperm morphology test, sperm count and analysis of sperm mortality and sperm motility, as per the standard procedures. The sperm count was decreased (p < 0.05) only on days 7 and 14 but sperm abnormalities increased on all days (p < 0.05). Sperm mortality increased at higher dose-levels (p < 0.05) except on day 42, and motility was affected by 30 mg/kg only on day 42. In conclusion, paraquat is a genotoxic and cytotoxic agent to germ cells in the male rat

Deterrent Factors in Urban Farming Participation

Urban farming is the practice of cultivating, processing, and distributing food in or around urban areas. Urban farming is a relatively new trend in Malaysia and has increased in recent years. As urban farming remains to be promoted by municipal governments and others, it is essential to understand how to ensure these projects are viable. This study was conducted to identify the deterrent factors that hinder the "community buy-in" in the urban farming projects and how to overcome the problem so that "community buy-in" in the urban farming project will be achieved and sustain in the future.Keywords: Urban Farming; Deterrent Factors; Participation; Community Buy-IneISSN: 2398-4287 © 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning &amp; Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v5i13.206

Receptor mechanisms of thymoquinone-induced hypotension in normotensive rats

Nigella sativa (NS), more commonly known as ‘’Habbattu Sauda’’, is a plant that is traditionally used to control hypertension. Evidence based studies revealed that NS exerts diuretic and blood pressure lowering effect in spontaneously hypertensive rat. While the volatile oil of NS acts centrally by indirect and direct mechanisms to induce cardio-depressant effect in urethane-anaesthetized rats, Thymoquinone (TQ) represents the main active constituent in the volatile oil, which could be the principal substance of the direct mechanism. Objective was to evaluate the hypotensive effect of TQ and its dose-response relationship in normotensive adult rats using the non-invasive tail-cuff technique. To investigate TQ mechanism of action through muscarinic and β adrenergic receptors. Three doses of TQ (2.5, 5 and 10 mg\kg) were used for assessing TQ hypotensive effect in 3 groups of rats (n=5) under sodium pentobarbital anesthesia. TQ was administered intraperitoneally, and mean arterial blood pressure (MAP) was obtained from recording systolic and diastolic pressure readings using the non-invasive tail-cuff technique and the dose-response relationship was obtained. MAP was then measured for other 2 animal groups pretreated either with atropine (P-at) or propranolol (P-pro) followed by 10 mg/kg TQ. This study confirms the dose-related hypotensive effect of TQ. The study showed that the mechanism of TQ-induced hypotension involves at least stimulation of vascular muscarinic receptors, but not β-adrenergic receptors. This study provides an evidence for the traditional use of Nigella sativa for treatment of hypertension

Feasibility study of small core diameter polymeric optical fibers (POF) from poly(methyl methacrylate)

This work describes the fabrication and evaluation of small core diameter Polymeric Optical fibres (POF) prepared from Poly(Methyl Methacrylate) (PMMA). Based on prior study, POF has a very interesting property in terms of short-reach local area networks due to the simpler manufacturing process and inherent immunity to electromagnetic interference and radiation. It can overcome the limiting factors of conventional glass-based optical fibre in terms of cost-effective, flexibility and easy installation. This study focused on introducing effective fabrication method to produce small diameter PMMA POF core using extrusion process. Prior to extrusion, we managed to produce PMMA cores with diameters of 650 μm, 750 μm and 850 μm. Based on the outcome of this study, the drawing tension and extrusion temperature have been identified as major influences on core diameter. The SEM images indicated that dense structure and clean surface whereas DSC and TGA analyses revealed that almost similar glass transition temperature and degradation weight loss in between fabricated PMMA core and industrial polymer optical fibre

Optimization of gold and silver nanoparticles production by laser ablation in deionized water

Colloidal solutions of gold and silver nanoparticles (NPs) were synthesized using a Q-switched Nd:YAG laser (1064 nm, 6 ns, 1 Hz ) ablation. Gold and silver bars were immersed in deionized water and irradiated by laser pulses for 4 min. The laser fluence was verified within the range of 21 – 39 J/cm2 with a fixed beam diameter of 1.6 mm. The effect of laser pulse fluence on both size and ablation efficiency of gold and silver nanoparticles were studied. The optical spectral characterization and morphological analysis of these nanoparticles were carried out by UV-Vis spectrophotometer and transmission electron microscopy (TEM), respectively. The average particle size for Au and Ag are 38.0 ± 10.3 nm and 31.3 ± 10.5 nm at corresponding optimized laser fluence of 31 and 25 Jcm-2 respectively

Antihypertensive and antihyperlipidemic activities of thymoquinone in l-name hypertensive rats

Objective: of this study was to evaluate the antihypertensive potential of Thymoquinone TQ and to investigate the underlying mechanism of action. Method: Hypertension was induced in in Sprague Dawley rats (n = 40) by administration of L-Nitro-Arginine Methyl Ester (L-NAME) in drinking water for 4 weeks. At the end of induction period, rats were divided into 6 groups (n = 8); TQ2.5+L-NAME, TQ5+L-NAME, TQ10+L-NAME, captopril+L-NAME, L-NAME only and control. Mean arterial pressure (MAP) and hear rate (HR) were recorded by the non-invasive tail cuff technique weekly for 28 days. Then animals were sacrificed and blood was collected for determination of ACE activity and aldosterone concentration using ELISA. Lipid profile (total cholesterol, LDL, HDL, TRG) was assayed twice; at the end of induction period and at the end of treatment period. Results: TQ reversed the established hypertension in TQ5 and TQ10 groups, and prevented further increase in MAP in TQ2.5 group. Unlike captopril treated group, TQ antihypertensive activity was associated with an increase in serum aldosterone concentration and ACE activity. TQ treatment at the high dose significantly lowered total cholesterol and LDL levels in comparison with the healthy control group at the end of the 4th week of treatment. Conclusion: This study confirms the antihypertensive effect of TQ which did not take place through inhibition of ACE, but probably through blocking angiotensin II receptors