Showing 6 results for Kamkar
Volume 5, Issue 3 (9-2017)
Abstract
Background: In this study for the first time terrestrial laser scanning survey was implemented on upland Hyrcanian forest, through which a and new method was applied to automatically extract DBH and tree position as a necessary step for height calculation and fitting the clustering as a circle.
Materials and Methods: Tree height extracted by fixing a cylinder around the trees center. The accuracies of these methods were investigated by field measurement. Among 4 shapes fitting algorithm, Monte Carlo had more suitable result to fitting circle in each height above the ground.
Results: Tree detection rates were 85% for Carpinus betulus and 87% for Diyospyrus lotus with respect to field measurement. R2 and RMSE for DBH measurement were 0.98, 2.06 cm for Carpinus betulus and 0.98, 1.26 cm for Diyospyrus lotus. Value of R2 and RMSE for height measurement were 0.96, 3.37 meters and 0.93, 3.02 meters for Carpinus betulus and Diyospyrus lotus, respectively.
Conclusions: The accuracy of DBH by TLS is very suitable, and about the height of trees we extracted underestimated value in comparison to field measurement and that we need to develop more effective algorithms in order to reach more accurate measurement of trees’ height in Hyrcanian forest.
Volume 11, Issue 1 (Winter 2023)
Abstract
Aims: There are few studies on the effectiveness of this type of management on soil properties of Golestan province as the main agricultural pole in Iran. The purpose of this study is to investigate the effect of limited tillage on improving biological soil quality indicators.
Methods: Three types of operations which include No Tillage (NT), Minimum or Occasionally Tillage (OT or MT) and Conventional Tillage (CT) were selected. From each management, 30 samples were taken at depths of 0-30 cm. Microbial respiration, microbial biomass, urease, acid and alkaline phosphatase, dehydrogenase and cellulase activity were measured.
Findings: Conservation tillage (ST) which include both MT and NT increased acid and alkaline phosphatase by 1.6 to 2.5 times. The reverse trend was observed for cellulase, which showed a decrease from 37.5% in MT to 25% in NT. Urease and dehydrogenase increased by 14 and 18% in MT and decreased by 5.7 and 10% in NT. Microbial biomass and microbial respiration increased by 1.8 and 2.5 times in MT and in no tillage, operation decreased by 15 and 44%.
Conclusion: The emphasis is on the advice of ST, However, it seems that some points related to the promotion of this method in agricultural lands should be considered. It seems that MT has a better condition for enzyme activity than NT. Low enzyme activity in NT conditions may reduce the availability of nutrients and thus reduce the yield, then extension experts should be inform the Farmers.
Volume 13, Issue 54 (8-2015)
Abstract
Earlier toxicological studies demonstrated that acrylamide is carcinogenic and most acrylamide in food is formed when asparagine amino acid reacts with certain naturally occurring sugars such as glucose.Inhibition, even reduction, of acrylamide formation during processing of foods, can help to produce more healthy food and, consequently, promote food safety. The objective of this study was to investigate the effects of the autolysed yeast of Saccharomyces cerevisiae, vitamins niacin (B3) and pyridoxine (B6) on acrylamide formation in chemical model. In this study the effects of different concentrations (0.025, 0.25 and 0.5 mmol) of autolysed yeast of Saccharomyces cerevisiae, vitamins B3 and B6 on acrylamide formation were evaluated in a chemical model. The acrylamide level was determined by Gas chromatography- mass spectrometry (GC/MS). According to the results vitamins B3, B6 and autolysed yeast of Saccharomyces cerevisiae, could reduce effectively acrylamide formation and vitamin B3 at concentration of 0.5 mmol was the most effective (p<0.05). This study indicated that these three additives could significantly reduce the acrylamide formation.
Volume 17, Issue 11 (1-2018)
Abstract
This paper presents an experimental and numerical investigation of phase change material melting in a rectangular enclosure. The aim of this research is the study of the effect of the tilt angle of the enclosure on the flow structures and the melting rate. In the experimental section, the visualization of the melting process is carried out by the photography of the phase change material through a transparent enclosure. Then, the image processing of the photographs is performed to calculate the instantaneous liquid fractions. The variation of the solid-liquid interface by tilting the enclosure clearly implies the evolution of the flow structures in the liquid phase. Numerical simulation is performed using the enthalpy-porosity approach for tilt angles of 90, 45 and 0o and wall temperatures of 55, 60 and 70 oC. The results show that by decreasing the tilt angle from 90o to 45o and 0o, the melting times are 52% and 37% less than that of the vertical enclosure. Melting time reduction in the inclined enclosure is due to the formation of the vertical flow structures and thermal plums in the liquid phase. By Increasing the Stefan number from 0.36 to 0.43 and 0.55 the thermal energy storage increase by 5.4% and 13.8%, respectively. Also, a correlation is developed to predict the thermal energy storage in the tilt enclosures using nonlinear regression.
Volume 20, Issue 6 (June 2020)
Abstract
High corrosion resistance, proper mechanical properties, and biocompatibility of Ti-6Al-4V alloy make it suitable for medical (dentistry and orthopedic implants), military and electronic industries. The greatest disadvantages of this alloy are poor wear resistance, low fatigue strength and poor tribological properties. The aim of this study was to apply an adhesive coating to improve both corrosion and wear properties of the Ti-6Al-4V alloy. Surface modification of alloy was done by nitrogen plasma nitriding in both electrolyte plasma and atmosphere plasma environment. Finally, the TiN layer was coated on the modified samples, using cathodic arc evaporation technique. The microstructural investigation, surface morphology, and coating thickness were studied by field emission scanning electron microscope (FESEM) equipped with energy dispersive spectroscopy. The grazing incidence X-ray diffraction (GIXRD) was applied to study the phases in the coatings. The corrosion resistance was studied with potentiodynamic polarization and electrochemical impedance spectroscopy. The wear resistance and the coating coefficient of friction were tested with pin-on-disc machine. The corrosion resistance of the samples was improved by applying the coatings and the plasma-nitride/TiN double-layer coating showed the best corrosion resistance with current density of 1.46×10-7A/cm2 and corrosion potential of -0.3V. On the other hand, the lowest thickness reduction in wear test was observed in double-layer coatings, so that the thickness reduction for both double-layer coatings, was less than 4μm, after 300m sliding.
Volume 23, Issue 4 (7-2021)
Abstract
To investigate the effect of inoculation with Rhizobium legominosarum and Pseudomonas fluorescens on grain yield, leaf area index, and dry matter accumulation and allocation of Vicia faba L., an experiment was conducted as a split-plot in a randomized complete block design with four replications at Agricultural Research Station of Golestan Province, during the cropping seasons of 2015-2017. As the main-factor, Rhizobium was considered at two levels of with and without inoculation, while the sub-factor included Pseudomonas in density levels of 0, 9×103, 9×105, 9×107, and 9×109 cells or CFU mL-1 of inoculants. A logistic model by SAS, was used in order to estimate the changes in the leaf area index and the dry matter accumulation. Combined analysis of variance for the two years of study indicated that the climatic conditions influenced the bacteria effects. In the second year (less temperature and rainfall), the traits (maximum leaf area index, maximum dry weight and grain yield) indicated a significant reduction in comparison with the first year. P. fluorescens had a significant positive effect on grain yield in the two years. None of the bacteria had significant effect on maximum leaf area index. Results of the first year showed a positive effect of the inoculation of Rhizobium on maximum dry weight (8%) in comparison with the control. Co-inoculation of Rhizobium with Peseudomonas (9×105 CFU mL-1) led to the greatest dry matter distribution coefficient for stems in podding stage. In the second year, Peseudomonas (9×109 CFU mL-1) increased maximum dry weight (23%) in comparison with the control. Also, the density increase of Peseudomonas under co-inoculation with Rhizobium led to a significant reduction of the day to maximum LAI. In conclusion, co-inoculation Rhizobium with Pseudomonas can have a positive effect on the growth indices of faba bean.
