Wild almond (Amygdalus scoparia Spach. ) is a drought resistant species with a wide spatial distribution that is extensively used in arid and semi-arid afforestation plans of Iran. Increasing the success of rehabilitation of deforested areas and classification of germplasms entail employing seed resources with good germination rate. To investigate the effect of drought stress on seed germination traits of wild almond populations in Fars province, a factorial experiment was conducted in a completely randomized statistical design. Almond populations were tested on 7 levels (Marvdasht, Pasargard, Arsanjan, Fasa, Kavar, Darab and Khonj), and osmotic stress of polyethylene glycol was studied in 4 levels (0,-0. 05,-0. 1 and-0. 5 MPa). Results of analysis of variance (ANOVA) showed that the main effects of water stress, population and their interactions were significant on all indicators of germination at p ≤ 0. 01. In addition, a diverse sensitivity of populations was observed to levels of drought stress. Increasing the water potential in the germination media had an adverse effect on most seed germination traits. At the highest drought stress levels, the average germination time in populations located in northern Fars was more than those in the southern populations. The population of Khonj showed the highest germination percentage, coefficient of velocity of germination, germination index, and germination rate index and germination value compared to the other studied populations. Using the seeds of this population is therefore recommended if approved in field trials.

The terminal velocity and coefficient of friction data are necessary for designing of handling and separating equipments. The terminal velocity data are also valuable in designing pneumatic conveying, fluidized bed dryer and cleaning equipments. In this paper, the terminal velocity and coefficient of static friction of saffron flower and its components (stigma, stamina, petal and stem) were determined as a function of moisture content. The experiments were conducted on saffron flower selected from fields of Kashmar. The data was statistically analyzed using factorial experiments with completely randomized design. The results showed that the terminal velocity of the saffron flower, stigma, stamina, petal and stem at moisture content of harvesting level to 40% (w.b.) were in the range of 1.03 to 5.13 m/s. With decreasing moisture content from harvesting level to 40% the terminal velocity of the flower and stem decreased significantly but the terminal velocity of the stigma, petal and stamina were not decreased significantly. The terminal velocity of the petal was the minimum value at the three moisture content levels. The coefficient of friction of saffron flower and its components on the friction surfaces were in the range of 0.52 to 1.1. The friction coefficients of all the components except the stem were the maximum values on polyethylene surface. The coefficients of friction were the minimum values on galvanized iron surface for all of the components. With decreasing moisture content from harvesting level to 40% (w.b.) the average values of coefficient of friction increased significantly for all of the components. The coefficient of friction of the stigma and flower were the maximum and minimum values, respectively at different levels of moisture content. Generally, at moisture content of harvesting it is possible to separate the flower, petal, stamina, stigma and stem from each other with changing air stream velocity. As well, it is possible to separate the petal from the others components at moisture levels of 70% and 40% (w.b.) using wind column device.

The Float method is a quick approximation technique for measuring velocity and thus flow rate. Surface velocity obtained by the Float method of correction factor is multiplied by the average velocity in the cross section obtained. This coefficient by the The United States Bureau of Reclamation (USBR) to measure the Float method is presented. Surface velocity coefficients published by USBR are based solely on average water depth. But other hydraulic factors such as longitudinal bed slope, the wall roughness height, the shape of the channel cross section, the location of the float object and... may also affect the value of the coefficient. In this study the effect of these parameters on the surface velocity coefficient in a rectangular and compound open channel studied and the results are compared with the coefficients published by USBR. The results indicate that these parameters are the effective surface velocity coefficient and considering effect of other parameters in addition to the average water depth, be accuracy of the float method could significantly increase.

Efficient seed germination and rapid and uniform seedling emergence are important in commercial agriculture. Therefore, the use of strategies to improve germination and seedling establishment is necessary for increasing productivity. Hydropriming has been suggested as a simple pre-germination strategy to improve seed performance. In this study, the effects of different durations of hydropriming (10, 24, 48 and 72 hours) at different temperatures (10 and 25oC) compared to unprimed seeds on the vigor and germination performance of five milk thistle accessions (Ahvaz, Sari, Esfahan, Dezfol and Gachsaran) were evaluated. An experiment was conducted as a factorial experiment based on a completely randomized design with three replications. germination performance was evaluated by final germination percentage, mean daily germination, mean germination time, coefficient of velocity of germination, Timson's index, time to reach 50% the final germination percentage, germination value, coefficient of uniformity of germination, length and dry weight of seedlings and vigor index. The results show that germination capacity, germination rate and seedling vigor indexes increase significantly in hydroprimed seeds at temperature of 10oC, whereas decrease in hydroprimed seeds at temperature of 25oC. Our results also show that the efficacy of hydropriming on seedling emergence and vigor traits depends on the priming duration and temperature. Hydropriming at 10˚C indicated the most effective on germination indicators and seedling vigor when compared to unprimed seeds. In addition, the comparison of germination and growth indicators in different durations of hydropriming in five milk thistle accessions indicated that the best duration of hydropriming for Ahvaz and Gajsaran is 72h, for Sari and Dezfol is 48 and 72h and for Esfahan is 10 and 24h. Therefore, the effect of hydropriming on germination performance and seedling vigor depends on plant association and hydroperiming time and therefore, the selection of the best condition for hydropriming will improve the seed germinability and vigor.

The present experimental study was done aimed to investigate dynamic of a single bubble rising through wall-bounded flow at high Reynolds number. Thus, Rhamnolipid biosurfactant was added to stagnant fluid and bubble diameter was controlled between 2. 5 and 3. 5mm. The resulted Reynolds number was in the range of 400 to 900 depends on biosurfactant concentration. Rhamnolipid has a low toxicity, a high biodegradability and good stability at a wide range of temperatures. The results showed that terminal velocity linearly depends on Reynolds number. Furthermore, drag coefficient is related to Eö, tvos number and is autonomous to Reynolds number. Finally, to estimate terminal velocity and drag coefficient, four empirical correlations were developed. Relative errors of the proposed correlations were less than of 3. 35% and 1. 97% for velocity and dimensionless velocity equations, respectively, and average errors of two equations proposed for drag coefficient were 4. 44% and 3. 26%.

Introduction Drought stress has become the major limitation factor on plant yield at global scale. It is due to the current environmental changes not only in dry areas but also in temperate ones. Deficit irrigation allows to the plants receive water lower than request. Sugar beet production requires supplementary irrigation in sugar beet producing areas such Mediterranean regions, but recently drought stress has restricted sugar beet cultivation in these areas. In arid and semi-arid regions, sugar beet production is limited by insufficient rainfall or restricted the availability of irrigation water. Breeding new cultivar for drought tolerance, developing new irrigation and soil management techniques and innovating new cultural practices may contribute to improve yield and quality of sugar beet under drought conditions. Sugar beet is one of the most important crops. It is also well recognized that drought stress is the main restrictive factor for sugar beet yield. However, the response of sugar beet to drought stress has been insufficiently studied. Jasmonic acid is a member of plant growth regulators named jasmonates which are important cellular regulators involved in several developmental processes such as seed germination, root growth, fertility, fruit ripening and senescence. Most of the plant parts contain jasmonates and the highest concentration appears to be present in reproductive tissues whereas much lower levels are found in roots and mature leaves. Till now it is considered that jasmonates particularly methyl esters of JA (Me-JA) as a chemical stress agent mimicking the effect of that appear in response to external stress factors inducing senescence. Materials and methods To explore the germination mechanism of drought-stressed sugar beet improved by exogenous jasmonic acid, and provide a theoretical basis to sugar beet direct sowing technology for water deficit and the effects of soaking with jasmonic acid on germination status, an experiment was conducted in factorial randomized complete design with four replications in laboratory, Faculty of Agriculture, University of Shahrekord in 2016. In this experiment, treatments included five levels of drought treatments (distilled water,-0/2,-0/6,-1 and-1/4 MPa with PEG) and seed soaking with jasmonic acid (0 (control), 5 and 10 µ M for 2 days. germination percentage and rate, shoot and length, shoot weight, mean germination time, coefficient of velocity of germination, relative germination, allometry coefficient, seed length and weight vigor index were measured. Results and discussion The results showed that drought stress and jasmonic acid on germination indexes including germination percent and rate, shoot and root length, shoot weight, coefficient of velocity of germination, relative germination, allometry coefficient and seed length and weight vigor index significantly decreased under drought stress, while, mean germination time increased. Drought stress in 1/4 MPa level decreased germination percentage and rate, shoot and root length, shoot weight 90, 84, 49, 44 and 33 percent as compared with control, respectively. In other hand, soaking with exogenous jasmonic acid improved all of germination indexes, while mean germination time decreased under drought stress. Moreover, interaction effect drought and jasmonic acid on germination indexes showed 5 µ M jasmonic acid had highest germination percent and rate, shoot length and weight, coefficient of velocity of germination, relative germination, and seed length and weight vigor index. The highest germination percentage and rate was detected when 5 µ M jasmonic acid under non-stress that increased 21% as compared with control, while the lowest was detected when pre-soaking water under 1/4 MPa. Also, highest increase in mean germination time was recorded under 1/4 MPa with pre-soaking water, whereas, the lowest was measured under non-stress with 5 and 10 µ M jasmonic acid. To conclude, soaking with 5 µ M jasmonic acid improved drought tolerance in sugar beet.

Heat transfer is a very important phenomenon for modeling heat equipment and scale up of slurry bubble reactors. For studying local heat transfer coefficient in slurry reactors, a column of 30cm diameter and of about 3m height which meets industrial reactor region was designed and constructed. In the experiments, 50-mm SiO2 powder having the same size of the catalyst of Fischer-Tropsch process was used as the solid phase and paraffin and air were used as the liquid and gas phases respectively. A specially designed heat transfer probe was used for measuring local heat transfer which consists of an electrical heat source element and two thermocouples for probing surface and fluid temperature measuring. By using this probe, local heat transfer coefficient was measured and the influence of superficial gas velocity and solid concentration were investigated. In all experiments, slurry phase height to the column diameter ratio was 4. The results showed that increasing the gas velocity from 2 to 25cm/s leads to an increase in heat transfer coefficient by about 65%; also an increase in the solid concentration increases heat transfer rate

Over the past century various equations have been proposed to predict the velocity and depth of uniform steady overland flow of water. The three most widely used expressions being these of Darcy-Weisbach, Chezy and Manning. The magnitude of resistance coefficients in equations such as those of Darcy- Weisbach, Chezy or Manning vary with flow velocity (at least). Using both original laboratory and field data, and data from the literature, the paper examines this question of the apparent variation of resistance coefficients in relation to flow velocity, even in the absence of interaction between hydraulics and resulting erosion of bed forms. Resistance equations are first assessed as to their ability to describe overland flow velocity when tested against these data sources. The result is that Manning's equation received stronger support than the Darcy-Weisbach or Chezy equations, though all equations were useful. The second question addressed is how best to estimate velocity of overland flow from measurements of slope and unit discharge, recognizing that the apparent flow velocity variation in resistance coefficients is probably a result of shortcomings in all of the listed resistance equations. A new methodology is illustrated which gives good agreement between estimated and measured flow velocity for both well-inundated sheet and rill flow.Comments are given on the predictive use of this methodology.

In this paper, a closed-loop optimal guidance with final position and velocity constraints is obtained by applying time-varying weighting coefficient in the performance index in order to shape the commanded acceleration. The control system is assumed to be linear, time-varying, and of arbitrary order with a throttle able engine. The acceleration due to drag is also modeled as a linear. Function with respect to velocity vector multiplied by a given junction of time. In addition, different weighting junctions are suggested for different acceleration constraints, such as maximum dynamic pressure, separation of stages, and zero acceleration at the final time. Finally, the performance of the guidance law for a combined weighting function is evaluated and discussed.