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Mazloomi K.,University Putra Malaysia | Sulaiman N.B.,University Putra Malaysia | Moayedi H.,Islamic Azad University at Estahban
International Journal of Electrochemical Science | Year: 2012

Our research shows that the amount of power consumed in the production of electrolytic hydrogen can be reduced considerably by targeting the resonant frequency of the water electrolysis cell. We tested this by measuring the cell voltage for the same levels of current in both DC and frequency controlled pulsed voltage applications. In order to reach any given level of electrical current, a noticeable reduction of cell voltage was observed when the applied voltage was in the pulsed form at a certain frequency. Therefore, less power was applied to the cell in order to maintain its current level at a desirable value. Higher production efficiency was observed since the volume of produced hydrogen is a function of cell current. The amount of power consumption was up to 15% less in the frequency controlled pulsed voltage application mode. Aluminum plates with surface areas of 1.5 cm2 and 10 cm2 and potassium hydroxide aqueous solutions with molarities between 0.1 M and 2 M were used as electrode plates and electrolyte materials respectively. The electrode plates were placed in different distances ranging between 5 mm and 50 mm, and the power sources were sat to reach current densities between 50 mA and 400 mA. Random combinations of the mentioned variables were tested several times in order to study the electrical behavior, frequency response and impedance characteristics of the experimental cell setups. © 2012 by ESG. Source


Alizadeh A.,Islamic Azad University at Estahban
Zeitschrift fur Naturforschung - Section C Journal of Biosciences | Year: 2015

Satureja rechingeri is a rare endemic and endangered species found in Iran. Its propagation, variations in essential oil and phenolic content, as well as antioxidant and antimicrobial activities at different phenological stages are reported in this study. The chemical composition of essential oils obtained by hydro-distillation from the aerial parts were determined by GC and GC-MS. A total of 47 compounds were identified in the essential oils of S. rechingeri at different phenological stages. The major components of all oils were carvacrol (83.6%-90.4%), p-cymene (0.8%-2.9%) and γ-terpinene (0.6%-2.4%). The total phenolic content and the antioxidant activity of methanolic extracts were determined with the Folin-Ciocalteau reagent and by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assay, respectively. Total phenols varied from 35.5 to 37.5 mg gallic acid equivalents/g dry weight (dw), and IC50 values in the radical scavenging assay ranged from 46.2 to 50.2 mg/mL, while those in the FRAP assay were between 49.6 and 52.5 μM quercetin equivalents/g dw. By the disc diffusion method and by determination of the minimum inhibitory concentrations (MIC), the essentials oils of the various phenological stages were found to have high activities against four medically important pathogens. Source


Mazloomi K.,University Putra Malaysia | Sulaiman N.B.,University Putra Malaysia | Moayedi H.,Islamic Azad University at Estahban
International Journal of Electrochemical Science | Year: 2012

Common industrial electrolyzers have a nominal hydrogen production efficiency of around 70%. High power dissipation value is the most important drawback of such systems since electric power expense has the largest share in the price of electrolytic hydrogen. The electrical impedance of an electrolysis cell causes a fraction of the applied energy to be wasted as heat while the electric current passes through it. As the prior publications show, many efforts are made to reduce this effect. According to the available literature, several internal and external variables are pointed out to have an influence on the electrical behavior of such cells. This paper provides an insight to these factors in regards to minimize the energy loss of the process of water electrolysis. © 2012 by ESG. Source


Pourmand S.E.,Islamic Azad University at Estahban | Rezaei G.,Yasouj University
Pramana - Journal of Physics | Year: 2016

Spectroscopic properties of the flashlamp-pumped Nd3+:YAG laser as a function of input energy were studied over the range of 18-75 J. The spectral widths and shifts of quasi-three-level and four-level inter-Stark emissions within the respective intermanifold transitions of 4F3/2 →4I9/2 and 4F3/2 →4I11/2 were investigated. The emission lines of 4F3/2 →4I9/2 shifted towards longer wavelength (red shift) and broadened, while the positions and linewidths of the 4F3/2 →4I11/2 transition lines remained constant by increasing the pumping energy. This is attributed to the thermal population as well as one-phonon and multiphonon emission processes in the ground state. This phenomenon degrades the output performance of the lasers. © Indian Academy of Sciences. Source


Alizadeh A.,Islamic Azad University at Estahban
Journal of Essential Oil-Bearing Plants | Year: 2013

The chemical composition of essential oil isolated by hydrodistillation from the aerial part of Salvia virgata under different ontogenesis (pre-flowering and full-flowering) conditions were determined using Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Twenty nine constituents were identified in S. virgata essential oils under different ontogenesis conditions that represented 98.36 - 99.18 % of the oils. The main components of the oil were β-caryophyllene (24.58-42.54 %), caryophyllene oxide (10.25-19.88 %), sabinene (8.64-19.58 %), 1-Octen -3-Ol (7.54-8.59 %), terpinene-4-ol (4.25-6.64 %) and α-thujene (3.74-6.46 %). The total phenolic content and the antioxidant activity of plant extract were determined by Folin-Ciocalteau and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays and ferric reducing antioxidant power (FRAP) assay respectively. Total phenols varied from 21.84 to 24.38 (mg GAE/g dw) and the IC50 in the radical scavenging assay ranged from 22.12 to 24.45 mg/ml and FRAP values ranged form 26.84 to 28.46 μM Quercetin E/g dw. Antimicrobial activity of the essential oil was evaluated using the disc diffusion method. The oils of various ontogenesis conditions showed moderate antimicrobial activity against Staphylococcus aureus and Candida albicans two medically important pathogens. © 2013 Copyright Har Krishan Bhalla & Sons. Source

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