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Gorgān, Iran

Jonoobi M.,University Putra Malaysia | Harun J.,University Putra Malaysia | Tahir P.M.,University Putra Malaysia | Shakeri A.,Gorgan University | And 2 more authors.
Materials Letters

The aim of this study was to isolate cellulose nanofibers from kenaf (Hibiscus cannabinus) stem using chemo-mechanical treatments. The fiber purification method included pulping and bleaching processes whereas the mechanical treatments employed to isolate kenaf nanofibers were grinding and high pressure homogenizing. Kenaf nanofibers were found to have diameters in the range of 15-80 nm while most nanofibers have diameters within the range 15-25 nm. Fourier transform infrared spectroscopy (FTIR) showed that the chemical treatments removed lignin and most of the hemicelluloses from the fibers. The thermal characteristics of the fibers were analyzed using the technique of thermogravimetric analysis (TGA) which demonstrated that these characteristics were enhanced noticeably both for the bleached pulp and nanofibers. On the other hand, the X-ray analysis indicated that both chemical and mechanical treatments can improve the crystallinity of fibers. © 2010 Elsevier B.V. All rights reserved. Source

Armin M.,Gorgan University | Abdolrassoul S.M.,Gorgan University of Agricultural Sciences and Natural Resources
Journal of Applied Biological Sciences

With the ever increasing human population and the industrial complexes catering for the need of this population, natural resources have been put under huge pressure. Forests are no exception; hence attempts to rebuild and rehabilitate the destructed and degraded forested areas are of high importance. Replantation of forest is a practical method for reversing the downgrading trends in the northern forests of Iran. Eucalyptus grandis is believed to be one of the most suitable species for afforestation in the north of Iran. We used a fuzzy multi-criteria approach towards land suitability assessment for plantation of Eucalyptus grandis in Gharnaveh Watershed of the Golestan Province of Iran. In the process, climatic, edaphic and topographic factors were employed as the criteria for suitability assessment. Membership functions were used to standardize factors and the analytical hierarchy process (AHP) was also applied for assigning weights to the criteria. The most important factors for plantation of the tree species was recognized as rainfall, slope and pH. The results showed that around 3570 hectares, close to 58% of the total area of the study site was suitable for plantation with Eucalyptus grandis. The approach used here can be utilized in other similar studies as an exemplary work for scientific site allocation for different plant species. Knowledge of the attempts towards afforestation that includes the ecological needs of the species used for afforestation is the key for the success of such efforts. Source

Fallah M.,Guilan University | Shabanpor M.,Guilan University | Ebrahimi S.,Gorgan University
Environmental Earth Sciences

In recent years, petroleum products and by-products have been widely used chemicals in soil habitats, which change the soil properties and quality of groundwater due to solubility, volatility and biodegradability of these pollutants. The aim of this research was to investigate the impacts of kerosene and gas oil pollutants on the breakthrough curve (BTC), soil water retention curve (SWRC) and some physical and chemical properties of the laboratory-contaminated soils. For this purpose, some water-saturated soils were artificially contaminated in the pulse condition inside some glass cylinders by applying half and one pore volume of these pollutants. Furthermore, parametric investigations of the soil retention curves were performed using RETC software by Van Genukhten, and Brooks–Corey equations in the various suctions and the soil properties were determined before and after pollution during a 3-month period. The BTC revealed that kerosene flowed out of the soil with a sharper gradient and greater velocity than gas oil, especially on introduction of one volume of kerosene (triple times more than the 0.5 volume). The RETC results regarding the Van Genukhten model demonstrated slightly lower water-holding capacity in the contaminated samples than the unpolluted one. Contamination not only diminished the saturation moisture (Θs), but also reduced the residual moisture (Θr) and the SWRC gradient (n), while Brooks–Corey equation represented only one set of data for all conditions. It can be concluded that all apparent physical and chemical properties of soil have been changed by spill of petroleum hydrocarbon on the soil surface. Evaluation of both equations demonstrated more accurate prediction of the SWRC’s parameter by Van Genukhten compared to Brooks–Corey. The results of this research can be generalizable for the assessment of petroleum pollution impacts on the quality and changes of soil properties in terms of pulse contamination for approximately the same condition on a wider scale. © 2015, Springer-Verlag Berlin Heidelberg. Source

Similar to other Chondrostean fish, Persian sturgeon (Acipenser persicus Borodin, 1897) and Starry sturgeon (Acipenser stellatus Pallas 1771) have got Gymnovarian ovaries, and structure form of their reproduction system is such that eggs cannot readily leave it. In minimally invasive surgical technique, a small incision is made in the wall of oviduct so that the eggs can easily leave it with the minimal manipulation and also the broodstock can survive. The aim of this work is to determine the distance between gonopore and incision area according to size and species which results in a more accurate and flawless incision. The results of this study showed that the distance between gonopore and conjuncture area of the two oviducts depends on species and size of fish; this distance in Persian sturgeon with 115-191 centimeters fork length and Starry sturgeon with 122-143 centimeters fork length were 4.2-6.3 and 3.8-4.5 centimeters, respectively. This distance is more than the incision depth that is generally made on the wall of one of the oviducts. Source

Owlia P.,Shahed University | Nosrati R.,Shahed University | Saderi H.,Shahed University | Olamaee M.,Gorgan University | And 2 more authors.
Iranian Journal of Microbiology

Background and Objectives: Azotobacter vinelandii, a gamma-proteobacterium, is an obligate aerobic free-living gramnegative soil bacterium capable of fixing nitrogen. Oxygen transfer rate into the cell is reduced by the increase of alginate concentrations during the course of A. vinelandii cultivation. This phenomenon provides a low intracellular oxygen concentration needed for nitrogenase activity. The aim of this study was to design a simple strategy to explain the alginate production, cell growth and nitrogenase activity correlation in A. vinelandii under aerobic conditions. Materials and Methods: Thirty-five different soil samples were taken from the rhizosphere of agricultural crops of Iran. Enrichment and isolation strategies were employed for microbial isolation. Physiological and biochemical characteristics were determined. Molecular identification was performed using selective nifH-g1 primers. Alginate production and nitrogenase activity assay by each isolate of Azotobacter were carried out. Bacterial growth, alginate production and Nitrogenase activity were conducted by time-coursed quantitative measurements. Results: Total of 26 isolates were selected after enrichment, isolation, and screening. The isolate was identified by molecular tests as A. vinelandii. The highest alginate productions of 1.02 g/l and 0.91g/l were noted after 4 days in 8 isolates, cell biomass of which were estimated 4.88-5.26 g/l. Six of 8 isolates were able to fix atmospheric N2 on nitrogen-free medium. Rates obtained in isolates were in the range of 12.1 to 326.4 nmol C2 H4 h-1 vial-1. Conclusions: Nitrogen fixation and alginate production yielded significant and positive Pearson's correlation coefficient of R2 = 0.760, p ~ 0.02. Finally association between bacterial growth, alginate production and nitrogenase activity almost noticeable yielded significant and positive Pearson's correlation coefficient R2 = 0.723, p ~ 0.04. Source

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