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The effect of forest roads on the extent and type of fire damage occurred in forests and rangelands of the Neka County in Mazandaran province was investigated. For this purpose, all fire spots, stand number, percentage and type of injury and damage to tree species, and average diameter at breast height (DBH) were noted with 100% inventory; area and geographic location of access roads were determined using GPS. The results showed that distance from the main access road had a significant correlation with the area of ​​fire spots, but no significant correlation existed between the distance from the strip roads, skid ways, town of Neka and the area of ​​fire spots. The factors influencing fire severity were analyzed using the stepwise regression model. Model also showed that just the distance from the main access road affected the area of ​​fire spots. For every one meter increase in the distance from the main access roads, the area of fire spot was increased by 1.545 m². Further, the extent of fire can be controlled by reducing the distance from the main access roads.

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Pistachio endocarp lesion (PEL) is one of the most important disorders that has spread in the pistachio-growing regions of Rafsanjan and Anar in recent years and has caused great economic losses to farmers. In order to identify PEL symptoms, and investigate the biologic factors involved in the development of this disorder, on May 2016, 90 orchards with different levels of PEL, were randomly selected. The rate of development in each tree was scored in- to four levels. The incidence of this disorder was estimated to be 25.8% in Rafsanjan. The seeds with PEL symptoms were differentiated into six types based on the appearance of the symptoms. Then tissue from infected parts of each type were cultured in the PDA. From among the 18 prepared culture media, fungal growth was obtained only in five cultured plates. Isolated fungi were Ulocladium sp. Penicillium sp., Verticillium sp. and Fusarium sp. To prove their pathogenicity, the spore spray technique was used on detached cluster in vitro. None of the purified fungi caused symptoms similar to the symptoms of PEL. Isolated strains from the pistachio seeds with PEL symptom often were saprophytic and soil borne; they were abundant in the orchard and could be transferred to the shoots of trees under the influence of various factors, such as: tillage, soil splashing by rain drops, and wind. In this study, the role of these fungal agents on the development of PEL was rejected.

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In this study, the effect of number of stages on Tesla microvalve performance has been studied. To do this, different layouts including one to four-stage microvalves are investigated numerically. The main criterion is used for evaluation of valves performance is diodicity. Two-dimensional and steady state computations of the fluid flow have been utilized that reveal a strong dependence of diodicity on Reynolds number and the pressure drop. The results showed that for the same flow condition, the diodicity average of the two-stage microvalve is approximately 1.32 times of that of one-stage. Additional stages increase the complexity and they do not change the diodicity considerably. It is concluded that two-stage layout of Tesla type valve is the best option between the studied layouts. A two-stage layout of this valve in valveless micropump besides being compact, has the adaptability of the various functions. Also, the two-stage valve performance in three different sizes is compared with nozzle - diffuser type valve. Comparisons which are performed based on calculation of diodicity for applicable range of Reynolds numbers show that the diodicity is function of Reynolds number and is independent of the valve size. Also, the superiority of the Tesla type valve for higher Reynolds number and its weakness at lower Reynolds number are shown.

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Ductile iron pipes are widely used in modern drinking water and wastewater networks. They often produce by horizontal centrifugal casting process. In this reasearch, the finite element base package ANSYS software has been used for thermal simulation of horizontal centrifugal casting process of ductile iron pipes.The simulation includes obtaining temperature distribution of mold and cast during different temperature cycles. In the simulation, latent heat due to solidification, temperature-dependent thermo-physical properties of material, heat transfer coefficient in metal-mold interface due to mold coating and air gap and thermal boundary conditions proportional to practical conditions, are considered. In this paper, pouring process to get transient thermal distribution in main body of mold and cast are also simulated. The results of the thermal simulation show good agreement with the experimental results conducted in this study and literature. The results can be used as input data for the numerical model to estimate thermal fatigue life of a permanent mold. The results of simulation have shown that, the thermal resistance of the air gap and mold coating has a significant effect on the temperature distribution in the pipe and the mold. Pouring process causes temperature gradients in the axial direction in the mold and the cast.

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This study was conducted to determine the effects of arbuscular mycorrhizal fungi (Glomus mosseae and Glomus intraradices) symbiosis on mineral uptake of two pistachio cultivars (Pistacia vera cv. Qazvini and Pistacia vera cv. Badami-Riz-Zarand) grown in the greenhouse under different drought stress levels. Drought stress (DS) reduced the mycorrhizal colonization in both cultivars as well as nutrient uptake. The mycorrhizal plants had higher P, K, Zn and Mn concentrations than non-mycorrhizal plants regardless of soil moisture conditions while Cu and Fe concentrations were unchanged. Distribution of elements was affected by AMF treatments where all except P were accumulated more in leaves than in roots. Contrastingly, under drought conditions, the absorbed elements tended to remain in root tissue. In the case of P and Mn uptake, Qazvini was superior in comparison with Badami. In conclusion, it is suggested that AMF inoculation improves drought tolerance of pistachio cultivars at least in part through the enhanced uptake of slowly diffusing mineral ions such as PO4^2- and Zn²⁺. Moreover, arbuscular mycorrhizal (AM) colonization provides better osmotic adjustment which can be correlated with K⁺ accumulation in top portions of inoculated plants. Results of this study also emphasized that ‘Qazvini’ cultivar may be more tolerant to drought than ‘Badami’.

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Neurological diseases such as cancer, damage blood brain barrier and consequently cause more permeability in tissues. In general if there is damage to the brain tissues, the contrast agent used in MRI, diffuses outside the capillaries and the MRI picture brightness changes. The purpose of this paper is to show the effects of different parameters on the contrast agent diffusion in the brain capillary. In this study, the lattice Boltzmann method with multi-relaxation time (MRT) is used to simulate the flow in the capillary and porous media around it. The results show that the porosity in extravascular tissues (it shows the tissue damage), the kind of contrast agent and capillaries curvature have impact on the contrast agent diffusion in the tissues. The presented results show the effects of curvature on shear stress and thus on mass transfer in the capillary. It should be noted that the presented results have been evaluated by previous statistical and analytical results for flow in the damaged brain capillary with different permeability. It has been shown that the lattice Boltzmann method is able to simulate the complex problems especially in porous media.

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In this research an inverse design algorithm, called ball-spine algorithm (BSA) is developed on a 90-degree bend duct between the radial and axial diffuser of a centrifugal compressor with viscous swirling inflow to bend duct. The shape modification process integrates inverse design algorithm and a quasi-3D analysis code. For this purpose, Ansys CFX software, is used as flow solver and inverse design algorithm is written as a code inside it. Shape modification is accomplished for viscous and inviscid flow to check the effect of viscosity on convergence rate. Also, the effect of swirl velocity in shape modification process is investigated, by considering increased pressure as the target parameter. The algorithm reliability for swirling flow is verified by choosing different initial geometries. Finally, aerodynamic design of the bend duct with BSA is accomplished to reduce losses in 90-degree bend. Shape modification process is carried out by improving the current wall pressure distribution and applying it to the inverse design algorithm. Results show that convergence rate and stability of BSA are favorable for designing ducts with swirling viscous flow. So that, the pressure recovery coefficient of the 90-degree bend duct is 4%increased.

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The purpose of this paper is to investigate theLow-Density Lipoproteins (LDL) mass transfer in vessel walls using the Lattice Boltzmann Method (LBM). High Schmidt number of LDL leads to numerical instability of LBM.In order to solve this problem, LBM and finite volume method (FVM) are combined.In this hybrid method, the blood velocity field is solved by LBM using the single relaxation time, SRT, model and FVM has been used for LDL concentration equation. LBM is able to simulate flow and mass transfer for the Schmidt number, Sc, up to 3000 only if the time consuming multi relaxation time is used. However, the purposed hybrid method suggested in this article can be used to solve the problem for Sc as high as 107. Good agreement between our results obtained from the hybrid simulation and the available results in the literature and noticeable decrease in CPU time compared with when the LBM is used for both flow and mass transfer, indicates the ability of the hybrid method.Finally, the hybrid methodis used to simulate the mass transfer of LDL particles and investigate the effective factors for increasing the surface concentration, such as the size of LDL particles, wall suction velocity, wall shear stress, Newtonian and non-Newtonian fluids behavior and change of concentration boundary layer with various Schmidt number.

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This research investigates notch effect on fatigue life of HSLA100 steel which is widely applicable in the marine industry. Experimental tensile tests and rotating bending fatigue tests were performed on both smooth and notched cylindrical specimens and the corresponding mechanical properties and S-N curves were obtained. To better investigate the notch and also size effect on fatigue life of the specimens, two different notch geometries and specimen dimensions were used. To calculate the fatigue strength factor, stress distribution under bending load is simulated for smooth and notched specimens. Then, the stress distribution under bending load is converted to stress distribution under rotating bending load using an in-house developed code. Finally, using an in-house developed code, the fatigue strength factor of the specimens is calculated by weakest link theory. In order to better investigate the weakest-link theory, in calculating the fatigue strength factor, this factor is calculated from the classical methods and compared with experimental results. Finally, Comparison of theoretical with experimental results shows that the weakest-link theory gives better predictions than other classical methods and the results are closer to experimental ones. Also, Weakest-link theory uses the finite element results to predict notch effect. This facilitates the use of this theory in fatigue design of complicated specimens.

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The variation of wall shear stress (WSS) in the microvessels may damage the endothelial layers. It also changes the mass diffusion and sediment and may be considered as an important factor in the formation of the fatty plaques and causing heart disease. According to the importance of the issue, the aim of this paper is to study the effective parameters on the wall shear stress in microvessels. In this paper, the hybrid method, combined lattice Boltzmann and immersed boundary methods is used to simulate the red blood cell (RBC) motion in the plasma flow. It should be mentioned that red blood cell has significant effect on WSS, in this regard; the present results show that the blood rheological behavior has the important effect on WSS. The results also demonstrate the effect of stenosis severity and RBC location in different regions on wall shear stress and consequently causing heart, coronary disease. It should be noted that the presented results have been evaluated by previous numerical results for microvessels and the results show the ability of lattice Boltzmann method to simulate complex problems especially for modeling the deformable solid objects suspended in the fluid.

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In this paper, the results obtained from experimental measurements of average and turbulence quantities of a turbulent rectangular impinging jet hitting a fixed wall is reported using the laser doppler anemometry (LDA) method. The nozzle to plate distance is 10 times the nozzle width, and the tests are repeated for three different Reynolds numbers, namely Re=3000, 6000 and 9000. The aim of the current research was to investigate and comparise of flow in different Re and also to determine the two effective experimental errors on average velocities, namely data sampling and residence time in measurement volume. The results reveal that the previous stated correlation for prediction of the number of data required for ensuring independence of the average flow variables on the number of the sampled data is not sufficient by itself, and depending on the turbulence intensity of the flow, this correlation could become ineffective. Further, in the present study, the residence time is used for calculation of average velocities, and the results are compared with those obtained by particle image velocimetry (PIV) method. The comparison shows good agreement between the results from LDA and PIV when considering effect of residence time within the avaraging equations in the former method. The results show that the behavior and quantity of the dimensionless average velocities for various Reynolds numbers are identical at most cross sections of the flow domain while the dimensionless turbulent stresses have different quantities at different values of the Reynolds number.

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In this paper heat transfer through argon gas between two stationary walls of a nano sized channel, is investigated by the use of molecular dynamic method. Comparison between two and three-dimensional solutions shows that for accurate modeling of wall force filed on heat transfer, the accuracy of two-dimensional molecular dynamic solution is inadequate. Two-dimensional solution predicts the value for density and temperature less than the value of three-dimensional solution near each wall. Considering the effect of domain size on accuracy of thermal solution shows that domain size should be extended at least for one mean free path in periodic direction to have domain independent results. Distribution of fluid properties in the width of the channel shows that independent of implemented temperature difference, presence of the wall force field changes the temperature and density profile in one nanometer from each wall drastically. In addition to variation in density due to the wall force filed, temperature difference between the walls cause additional variation in density profile near walls. Increasing the temperature difference between the walls to value more than 20 degree, make a notable density variation to more than 5 percent in comparison with gas density distribution in isothermal walls case. Variation in density near walls due to temperature differences leads to mismatch between the non-dimensional temperature profiles and calculated thermal conductivity coefficient of the gas for various temperature differences.

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In order to simulate the heat transfer process from wall to fluid in nanochannel numerically, extensive range of spring constants with regard to wall material is used. In this paper, the effect of variation in wall spring constant on the heat transfer and distribution of the macroscopic properties of fluid has investigated. In this regard, heat transfer in argon gas between two stationary walls of a 5.4 nm nanochannel with Knudsen number 10 has simulated using the molecular dynamic method. Comparison between the results shows that by reducing the wall spring constant, the amplitude of wall atoms vibration increased so it makes the gas atoms to become closer to the wall surface that results in an increase in the heat flux and thermal conductivity coefficient of the gas. Evaluating the result reveals that while the spring constant reduces from k_s=1100εσ^(-2) to k_s=100εσ^(-2), the thermal conductivity coefficient of the gas changes from 0.11 mW⁄(m-K) to 0.27 mW⁄(m-K). Furthermore, the reduced distance between the gas atoms and wall surface results in a decrease in the temperature jump on the wall so it increases the gas density near the cold wall while it decreases near warm wall. Comparison between temperature, density and pressure profiles in the nanochannel height shows that regardless to the amount of spring constant variation, the maximum of these properties has occurred at σ⁄2 from the walls.

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The radios of particles in Dissipative Particle Dynamics (DPD) method is investigated numerically taking into account size and type of conservative force. In the most of previous studies, the DPD particles have been considered as a point center of repulsion with zero radios and hence sphere size is prescribed by the creation of a structure of frozen DPD particles. Although only in ideal gas state or zero conservative force the DPD point particle is meaningful and with conservative force the DPD particles have an intrinsic size which is assigned by the spherical impenetrable domain occupied by each particle when immersed in a sea of other particles. At first the appropriate method should be define to calculate the size of DPD particle. Different methods including Stokes-Einstein relation, Stokes law and radial distribution function (RDF) are studied and it is concluded that according to limitation of Stokes-Einstein and Stokes relations the RDF is the best method for evaluation of DPD particle size. In the following, the trend of DPD particle size changing and their distribution in the system with linear and exponential conservative force examined. At the end we demonstrate that the employing of exponential conservative forces for the colloid-colloid and colloid-solvent interactions but keep the conventional linear force for the solvent-solvent interactions achieve a well-dispersed suspension with different particle sizes without extra computation

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The design of a robust controller for the automatic landing system is investigated for an unmanned fixed-wing aircraft based on an external navigation system. Since landing is the most difficult phase of flight, the major accidents are occurring in the phase. So, providing a high-precision automatic landing system in presence of environmental disturbances is very important for UAVs landing. The used landing navigation system is founded on a portable land-based laser-optics system which can track the UAV and calculate the altitude and direction of it toward the center of runway. However, the navigation system is external; sending them to the UAV can be done with a delay. In this regard, UAV’s control systems must be designed such that the stability of aircraft is satisfied based on information of navigation system with considering the model uncertainty, noises, disturbance and navigation delay. So in this paper, a new robust stabilizer controller is suggested for UAVs to overcome these challenges with considering some limitation in the structure of the controller. Finally, simulation results based on laboratory software in the loop been presented. The results are indicating the capability of using proposed method for automatically landing of UAVs.

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Malva sylvestris belongs to Malvaceae familyThe biological active compounds of Malva sylvestris describe probably it’s biological activities and therapeutic activity. The purpose of this study was to investigate the antibacterial effect of Malva sylvestris on some pathogenic bacteria “in vitro”.In this study, the extraction was carried out by the maceration method. The pour plate method and disk diffusion method were adopted to determine the susceptibility of the pathogenic strains against Malva sylvestris extracts. The broth microdilution and fractional inhibitory concentration index (FICI) were employed to determine antimicrobial effect. The minimum bactericidal concentration was measured by pour plate method. The concentration 100 mg/ml of the ethanolic extract showed the best result on Streptococcus pyogenes and Staphylococcus aureus (p<0.05).  Enterobacter aeruginosa was resistant to most of the aqueous and ethanolic Malva sylvestris extracts. Minimum inhibitory concentration of the ethanolic extract of Malva sylvestris for Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Enterobacter aeruginosa were 8, 8, 64 and 64 mg/ml, respectively and the aqueous extract were 16, 32, 128, and 128 mg/ml, respectively.The ethanolic extract of Malva sylvestris had more inhibitory effect than the aqueous extracts on pathogenic strains. Furthermore, aqueous and ethanolic Malva sylvestris extracts showed greater inhibitory effect on gram-positive bacteria in comparison with gram-negative bacteria.

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Promising secondary metabolites of brown algae have been given particular importance, due to their various biological activities. In the present study, two extraction methods including maceration and ultrasound were performed to prepare extracts from brown algae including Padina distromatic, then, aimed to evaluate antioxidant, antimicrobial, and anti-Alzheimer’s activities of extracts. Padina algae extract prepared by ultrasound method had higher total phenol (43.25 mg GAE/g) and flavonoid content (24.59 mg QE/gDA). However, the maximum antioxidant activity was observed in algae extract prepared by maceration method. Padina algae extract prepared by ultrasound method had the highest inhibitory activity of acetylcholinesterase and the strongest inhibition of nitric oxide production was observed in this extract. Escherichia coli and Listeria innocua bacteria were more resistant to Padina algae extract than other microorganisms and the results of microbial test showed that Padina algae extract prepared by ultrasound method was more antimicrobial than maceration method. Collectively, the obtained results provide valuable evidence for antioxidant, anti-Alzheimer, and antimicrobial activity driven by Padina distromatic extracts which can highlight their possible approach in the therapeutic utilization.

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In recent decades, the demand for the use of functional compounds in food and pharmaceutical products has increased. The aim of this study was to compare the phytochemical compounds and antioxidant, anti-Alzheimer's and antimicrobial properties of Padina distromatic and Sargassum angustifulium algae extracted by ultrasound. The results showed that butanoic acid was the most important substance in Padina and Sargasum extracts. Total content of polyphenols, flavonoids and IC50 index of Padina extract and sargasum 43.45 and 46.63 mg GAE/g, flavonoid content 24.59 and 55.40 mg QE/g and IC50 index 10.38 and 30.77 g/ml respectively. The inhibitory activity of acetylcholinesterase (AChE) of Padina and Sargassum algae extracts was 42.5% and 25.16%, respectively. Nitric oxide (NO) inhibitory results showed that nitric oxide inhibitory activity increased with increasing the concentration of both Padina and Sargassum algae extracts (from 50 to 400 mg / ml). However, Padina algae extract had the strongest NO inhibitory activity at all concentrations. Padina extract had more antimicrobial properties compared to the algae extract of sargassum. The minimum inhibitory concentration (MIC) of Padina extract at 12.5 mg/ml was obtained on Staphylococcus aureus. Padina extract at 50 mg/ml had a bactericidal effect on Staphylococcus aureus. Finally, Sargassum extract should be used as natural antioxidant and Padina extract as natural anti-Alzheimer's and antimicrobial components.