فهرست مطالب a .mardani

Due to the numerous variables that may influence the soil-machine interaction systems, predicting the mechanical response of soil interacting with off-road traction equipment is challenging. In this study, deep neural networks (DNNs) are chosen as a potential solution for explaining the varying soil sinkage rates because of their ability to model complex, multivariate, and dynamic systems. Plate sinkage tests were carried out using a Bevameter in a fixed-type soil bin with a 24 m length, 2 m width, and 1 m depth. Experimental tests were conducted at three sinkage rates for two plate sizes, with a soil water content of 10%. The provided empirical data on the soil pressure-sinkage relationship served as the basis for an algorithm capable of discerning the soil-machine interaction. From the iterative process, it was determined that a DNN, specifically a feed-forward back-propagation DNN with three hidden layers, is the optimal choice. The optimized DNN architecture is structured as 3-8-15-10-1, as determined by the Grey Wolf Optimization algorithm. While the Bekker equation had traditionally been employed as a widely accepted method for predicting soil pressure-sinkage behavior, it typically disregarded the influence of sinkage velocity of the soil. However, the findings revealed the significant impact of sinkage velocity on the parameters governing the soil deformation response. The trained DNN successfully incorporated the sinkage velocity into its structure and provided accurate results with an MSE value of 0.0871.

Seedbed preparation, seeding, and transplanting are usually based on mechanical soil tillage. Tillage by cutting, mixing, overturning, and loosening the soil can modify the physical, mechanical, and biological properties of soil. These days, because of soil protection, the use of tillage tools is less and less recommended, and some implements such as cultivators are preferred to primary tillage tools such as plows. Experimental study of soil-tool interaction and field measurements of the mechanics of tillage tools are usually time-consuming and costly. On the other hand, the variety of variables and uncontrolled conditions add other dimensions to the complexity of this method. Also, the experimental and analytical methods do not have a comprehensive view of stress distribution and soil deformation in the soil-tool interaction process.

The main purpose of this study is to validate the results of numerical simulations in two phases of experimental tests: in soil bin environment and in finite element computer simulations. Experimental tests were performed in the soil bin environment of the Department of Mechanical Engineering of Biosystems, Urmia University, which has a soil bin facility with dimensions of length and width of 24 and 2 m, respectively, and has clay loam soil. Before experimental tests, soil preparation was performed by using some special tillage implements (harrow, leveler, and roller) which were attached to the soil bin (Figure.1). For experimental tests, a mechanism set consisting of two cultivator blades with a width of 15cm, a length of 20cm, and at a spacing of 35cm from each other was prepared and constructed. The relevant mechanism is designed to have the ability to change the tillage depth. Data were collected at three different soil depth levels of 6, 10, and 14cm in the soil bin with three replications. Data recording was performed using a 10-channel data logger with load cell connectivity and data storage ability. Also, in this study, the Drucker-Prager model as a finite element simulation method was used to calculate the stress during the soil-tool relationship. ABAQUS 6.10.1 software was used to simulate the cultivator tine. To solve the problem, the soil parameters were defined as presented in Table 1, and then the interaction between the soil-tool model and the necessary constraints, including boundary conditions, were defined. In the next step, meshing was applied to the constructed model.

In the results section, first, the results related to the amount of traction force required for the tillage tine in the simulation were calculated and then compared with the soil bin experimental tests. The traction force of the finite element simulation results for three tillage depths of 6, 10, and 14 cm in three principal directions is shown in Figure 4. A comparison of simulation and experimental results showed that there is a good agreement between them. In comparison, the simulation error range of the three depths of 6, 10, and 14 cm has shown 7.3, 5.6, and 4.16% at a speed of 2.5 kmh-1, respectively, as the velocity studied in this research. In the next section, the results of stress distribution contours in the soil and finally the overlap of the blade effect were discussed. Figure 6 shows the status of stress contours at three depths. By increasing the depth of the tine at the three depth levels studied, the stress range is shifted from the soil surface to its depth. For this purpose, at the maximum depth studied in this study (14 cm), it shows that the stress propagation to the soil surface is less than at other depths. Also, with decreasing depth, for a depth of 6 cm, the maximum stress was on the top soil surface, in other words, more deformation was seen on the soil surface.

Comparing the simulation results for predicting traction force with the results of experimental tests has led to relatively acceptable results and the maximum traction force prediction error at different depths has been about 7.3%.The distribution of stress in the soil was observed due to the tine depth. The highest intensity of stress propagation was observed at the soil surface; and the highest soil surface deformation at a depth of 6 cm. With increasing depth, both parameters of stress and soil surface deformation have decreased. According to the results of the studied blades, it is better to use these types of tillage tools only at lower depths. Also, in evaluating the overlap of the soil loosening zone in the side-by-side tines, it proves the superiority of the tine performance at lower depths.

Habrobracon hebetor Say, is one of the most important larval parasitoids of many lepidopteran pests, particularly the family Noctuidae. In this study, the lethal and sub-lethal effects of chromafenozide, pyridalyl and thiodicarb, as insecticides, were investigated on this parasitoid under laboratory conditions. Bioassay tests on adults were conducted based on contact method and sub-lethal effects were done based on demographic toxicology. According to bioassay tests, estimated LC30 values for chromafenozide and thiodicarb were 126.43 and 54.24 mg a.i./L, respectively. Since even with the application of three times more than that of the field concentration of pyridalyl (2250 mg a.i./L), maximum mortality percentage of insects was 19%; LC30 value was not estimated for this insecticide. In order to assess sub-lethal effects of insecticides, female wasps were exposed LC30 values of chromafenozide and thiodicard and the field concentration of pyridalyl (750 mg a.i./L). According to sub-lethal tests, insecticide treatments significantly affected duration of life different, fecundity and life table parameters. The intrinsic (r) and finite (λ) rates of increase were significantly lower in insecticide treatments than that of control. Overall, results showed that thiodicarb had the highest toxicity effect on H. hebetor, while pyridalyl and chromafenozide had less adverse effects on this parasitoid. Following field experiments and subject to confirmation of the results of this study, it is possible to use pyridalil and chromafenozide in integrated pest management programs.

The FUT3 gene regulates the expression of Lewis blood group antigens mainly Lea and Leb. The Lewis negative phenotype, is the result of an inactivated FUT3 enzyme that lacks glycosidase activity. Several single nucleotide polymorphisms (SNPs) may cause enzyme inactivation with different racial distribution. This study aimed to determine the frequency of these SNPs in Iranian blood donors.

In this cross sectional descriptive study, one hundred blood donors from Tehran Blood Transfusion Center were analyzed. Genomic DNA was extracted and the coding sequence of FUT3 gene was amplified with specific primers. PCR products were directly sequenced. Haplotypes were inferred by SNP Analyzer software.

A total of 15 SNPs including 10 nonsense SNPs were recognized. The frequency of most common SNPs was detected as 39%(202T>C), 37%(314C>T), 20%(59T>G), 9%(508G>A), and 8%(47G>C). Haplotype analysis revealed 13 haplotypes. The frequency of major haplotypes was detected as 66.2%(Le), 17.5%(le202,314), 4.3 %(le47,202,314), 4.1 %(le59), and 3.4%(le59,508).

Conclusions :

Our findings indicate that 202T > C, 59T > G and 508G > A are useful as major SNPs for detection of Lewis-negative alleles in genotyping of Lewis blood groups; they can also play an effective role in large-scale studies associated with diseases in our population.

Lipid oxidation is the oxidative deterioration of unsaturated fatty acids via an autocatalytic radical chain process that leads to the deterioration both the sensory and nutritional quality of lipids. Lipid oxidation has adversely consequences for the quality of lipid and human health by producing a wide range of harmful reactive radicals. Using antioxidants is the most important defense means to delay or slow rate of lipids oxidation by scavenge chain-propagating peroxyl radicals. Recently, the interest in natural antioxidants has been increased due to the reported toxicologically negative effects of the synthetic antioxidants.The most powerful types of natural antioxidants are the phenolic acids, which are widely found as secondary metabolites in plant kingdom acids. A relationship between the antioxidant activities and the structures of the phenolic acids were the object of a number of investigations. The number of hydroxyl groups and the position of these groups in the phenolic ring have a significant influence in antioxidant activity of phenolic acids. The activity increases in the following order: monohydroxyo< dihydroxy< trihydroxy. Gentisic acid (2,5-dihydroxybenzoic acid) is one of the interesting subset of dihydroxybenzoic acids, present in many natural sources such as citrus fruits, grapes, olive, peanuts and herbs. The antioxidant activity of the Gentisic acid was the object of lot investigations. Gentisic acid has been reported to has anxiolytic, antirheumatic, anticarcinogenetic, anti-inflammatory and antimutagenic properties. The capacity of Gentisic acid to prevent lipid oxidation is related to its mechanism of antioxidant activity. The relative positions of the two hydroxyl groups in Gentisic acid phenolic ring have significantly influence in antioxidant property.

Purifed triacylglycerols of sunflower and olive oils were obtained by removing all pro- and anti- oxidants by adsorption chromatography: 130 g of oils were purified twice by passing in a glass column (25 × 2.5 cm i.d), packed with 70 g of aluminum oxide 60 activated at 200 °C for 3 h in bottom and, 15 g of silica gel activated at 160 C for 3 h in upper layer. Triacylglycerols were drawn in dark through the column by suction without solvent. Then soybean and olive oil samples, containing different concentrations of the Gentisic acid (0.02, 0.04, 0.08, 0.16 and 0.32 wt. %) were prepared by adding aliquots of its solutions in purified acetone. The solvent was removed under nitrogen. 1-mm layer of the prepared oils samples (4 g) were oxidized in a Petri dish having a diameter of 9 cm Under these conditions, the process took place in a kinetic regime, i.e., at a sufficiently high oxygen concentration which the diffusion rate does not influence the oxidation rate. Oxidation was performed in dark at 60, 80, 100 and 120 °C.The oxidation process was followed by withdrawing samples at certain time intervals and subjecting them to spectrophotometric determination of the peroxide value (PV) as primary oxidation products and different kinetic parameters i.e. stabilizing factor (F), oxidation rate ratio (ORR), and antioxidant activity (A). In order to PV measurement, the vegetable oil samples (≤0.01–0.30 g) were added to a glass tube containing 9.8mL chloroform–methanol (7:3 v/v) and were vortexed for 2–4 s. 50mL of ammonium thiocyanate solution (30 % w/v) was added the sample was mixed on a vortex mixer for 2–4s. Then iron (II) chloride solution [50mL, (0.4g barium chloride dehydrate dissolved in 50mL H2O) + (0.5 g FeSO4·7H2O dissolved in 50mL H2O) + 2mL 10 M HCl], with the precipitate, barium sulfate, filtered off to produce a clear solution]) were added, and the sample was vortexed for 2-4 s. After 5min incubation at room temperature, the absorbance of the sample was read against a blank sample (containing all the reagents except the sample) at 500nm (UV-VIS spectrophotometer, Model 160A Shimadzu, Kyoto, Japan). Results were reported as milliequivalents of oxygen per kilogram of oil. Kinetic curves of peroxide accumulation were plotted. The x-coordinate of intersection point of two straight lines fitted on the initiation and propagation stages of the oil oxidation was calculated as induction period (IP). Mechanism of antioxidative action was determined according to kinetic parameters and the based on the participation of Gentisic acid molecules and radicals in a series of reactions).

Gentisic acid as a phenolic antioxidant was effectiveness during autoxidation in both lipid systems (i.e. olive and soybean oil) without reactive free radicals production. The dependence of the parameter F on antioxidant concentration is linear only in the case of Gentisic acid-inhibited sunflower oil oxidation that showed the participation of antioxidant molecules mainly in reaction 7. The absence of F linearity in other treatments (α-Resorcylic acid in both olive and sunflower oils oxidation and Gentisic acid in olive oil oxidation) is due to the participation of the inhibitors molecules in the side reactions other than the main reaction of chain termination 7, namelyreaction 11 or/and 12. The mean rate of antioxidant consumption increased as the unsaturation degree of the soybean oil increased. Despite having the more appropriate performance in the olive oil sample, which normally contains higher amounts of oleic acid. The overall performance of Gentisic acid was attributed to the main reaction of chain termination (ROO• + InH ® ROOH + In•) as competed with the main oxidation reaction of chain propagation (ROO• + RH ® ROOH + R•). Due to the higher percentage of non-saturated fatty acids in soybean oil, antioxidant activity of gentisic acid promoted with increased concentrations, while in olive oil because higher content of monosaturated fatty acid (e.g. oleic acid), Gentisic acid participate in side oxidation reactions (InH + ROOH ® In • + R • + H2O) as prooxidant in high concentration.

The present study was performed to elucidate the mechanism of antioxidative action of Gentisic acid. It was concluded that Gentisic acid as a phenolic antioxidant was effectiveness during autoxidation in both lipid systems (i.e. olive and soybean oil) without reactive free radicals production. The mean rate of antioxidant consumption increased as the unsaturation degree of the oil system increased. Despite having the more appropriate performance in the olive oil sample, which normally contains higher amounts of oleic acid.

There are different methods in order to model soil-wheel interaction which Bekker equation and Wismer models are two of them. These models have been selected in this study for tire rolling resistance prediction and comparison with experimental tests. Using an appropriate model for accurate prediction of rolling resistance, is useful for energy management. In this study, soil power-sinkage modules related to Bekker model were obtained. In this way, a series of plates with different widths was pushed into the soil while the force and corresponding sinkage were being measured. The soil cone index was recorded using a penetrometer in several replications to compare the rolling resistance calculated by both models and from experimental data. The experiments were performed with a single-wheel tester in controlled conditions at three levels of tire pressure and vertical load. The vertical load on the wheel was varied during the test, but its travel speed was kept constant at 2.3 km.h-1 . The results showed that Wismer model in all experiments had better ability to estimate rolling resistance than Bekker model. Bekker model with higher tire pressure provided better estimate for rolling resistance, since the wheel had been turned almost into a rigid wheel.