Étude cinématique des événements binaires et ternaires obtenus par bombardement de cibles d'U, Th, Bi, Pb, Au par des deutons de 2,1 GeV

Une étude cinématique de la fission binaire et ternaire induite par des deutons de 2,1 GeV sur des cibles U, Th, Pb, Bi et Au est réalisée à partir des caractéristiques géométriques des traces des fragments des événements enregistrés dans un détecteur solide de traces en géométrie 4π. Moyennant certaines hypothèses, on établit la distribution en rapport de masse et en énergie des fragments. On a pu mettre en évidence qu'une partie des événements binaires dont l'angle projeté sur le plan perpendiculaire à la trajectoire de la particule incidente est différent de 180°, procèdent d'un même type de désintégration que les événements ternaires. De même, l'analyse cinématique des événements ternaires montre une certaine analogie avec le phénomène connu de la tripartition de noyaux lourds comme le californium par exemple, et pourrait expliquer la production d'une partie des isotopes légers et lourds déficients en neutrons attribués à de la fragmentation par les radio-chimistes

Electron beam irradiation of low-density polyethylene filled with metal hydroxides for wire and cable applications

The effects of electron beam irradiation for crosslinking of polymers used for wire and cable insulations are still being researched. In this research, the influence of electron beam irradiation on the different blends of low-density polyethylene (LDPE) filled with aluminum trihydrate and magnesium hydroxide (ATH, MH) were studied. It was revealed by melt flow index, tensile strength, and elongation at break tests that addition of MH to LDPE increases the adhesion forces inside polymer matrices more efficient than similar ATH/LDPE compounds. Field emission scanning electron microscopy test showed that MH is platy in structure and more homogenous mixed than ATH with LDPE. The results on thermogravimetric analysis and limiting oxygen index tests revealed that the thermal stability and incombustibility properties of MH blends are more efficient than similar ATH blends. Meanwhile, it was observed by smoke density test that MH blends produce the lowest smoke density compared with virgin LDPE and similar ATH blends. It was also observed that increasing irradiation by electron beam had impressive affections on the density, gel content, and mechanical properties for all the polymeric samples in this study

Effects of Nitrogen Application and Irrigation Water on Grain Yield and Water use Efficiency of Safflower in Isfahan

An experiment was conducted to evaluate the effects of different levels of nitrogen and irrigation on yield and yield components of safflower. Three nitrogen rates (0, 50 and 100 kg ha-1) under three irrigation levels (100% as control 80% as mild limited irrigation, and 60% of crop water requirement as severe limited irrigation) were investigated using a factorial laid out in a randomized complete block design with four replications. Nitrogen application led to a significant increase in leaf chlorophyll content, photochemical efficiency, leaf relative water content, leaf proline content , leaf area index, shoot dry weight, , number of buttons per plant, number of grains per button, grain weight, grain yield, harvest index and water use efficiency. Photochemical efficiency, leaf relative water content, leaf area index, shoot dry weight, number of buttons per plant, number of grains per button, grain weight, grain yield, harvest index were decreased and leaf chlorophyll content, leaf proline content and water use efficiency were increased as the level of soil moisture was decreased. The highest amount of grain yield was obtained with application of 100 kg/ha nitrogen under irrigation regimes of 100 and 80% crop water requirement. While, the highest value of water use efficiency was obtained with application of 100 kg/ha nitrogen under irrigation regimes of 80 and 60% crop water requirement. According to the results obtained in this experiment, the application of 100 kg/ha nitrogen under irrigation regime of 80% crop water requirement seems to be appropriate to achive highest values for both safflower grain yield and water use efficiency

Evaluation of Fluent Software for Simulation and Costruction of a Variable Rate Sprinkler for an Autonomous Irrigation System

Water scarcity is today’s world biggest challenge which requires different countries to manage their water resources in the most efficient way. Sprinkler irrigation increases water consumption efficiency due to more uniform distribution of water across the field. Precision farming is based on the site-specific use of inputs according to soil characteristics and plant needs. One of the main inputs for agricultural production is water. Thus, efficient use of water resources based on variable rate irrigation is considered to be a basic approach of precision irrigation. The main purpose of this study was to simulate and fabricate a variable flow sprinkler, applicable in solid set sprinkler irrigation system. The preliminary drawing of the proposed sprinkler, which equipped with a flow and pressure control plunger, was simulated using Fluent software. The actual sprinkler was then fabricated and evaluated in a field. The performance of the sprinkler was evaluated at three pressure levels, three plunger positions (at the points of the least and biggest sprinkler’s cross section for water passage) and three diameters of outlet nozzle opening. Results showed that the plunger had the capability of varying outlet flow and pressure in the sprinkler and trends in flow and pressure variation as affected by the plunger position was very complicated. The Fluent model for conditions with fully open of the plunger and half opened was effectively efficient. However, as the plunger closed the water passage more than the half of cross section, the model did not show an acceptable efficiency

Effect of Irrigation with Reclaimed Water on Fruit Characteristics and Photosynthesis of Olive Trees under Two Irrigation Systems

Introduction: Olive (Olea europaea L.) trees are mainly cultivated in the Mediterranean area and are grown for their oil or processed as table olives. Despite the fact that olive is known to be resistant to drought conditions due to its anatomical, physiological, and biochemical adaptations to drought stress, reports indicate that the olive can be adversely affected by drought stress, which has a negative effect on the growth of olive trees. In the absence of adequate supplies of water, the demand for water can be met by using improved irrigation methods or by using reclaimed water (RW). Reports have shown that recycled water has been used successfully for irrigating olive orchards with no negative effects on plant growth.Attention has been paid to reclaimed water as one of the most significant available water resources used in agriculture around large cities in arid and semi-arid regions. On the other hand, irrigation efficiency is low and does not meet the demands of farmers.In order to investigate the possibility of irrigating olive orchards with subsurface leakage irrigation (SLI) in application of reclaimed water, an experiment was carried out with the aim of investigating the effect of reclaimed water on photosynthetic indices and morphological properties of olive fruit. Materials and Methods: Research was conducted using a split-plot experimental design with two factors (irrigation system and water quality) on the campus of Isfahan University of Technology in Isfahan, Iran, on a sandy-clay soil with a pH of 7.5 and electrical conductivity (EC) of 2.48 dSm-1.PVC leaky tubes were used for the SLI system. The SLI system was installed 40 cm from the crown of each tree at a depth of 30 - 40 cm.At the end of the experiment fruit yield, weight per fruit, volume, length and firmness were calculated. A portable gas exchange system (Li-6400., LICOR, Lincoln, NE, USA) was used to measure the net rate photosynthesis (A), the internal partial pressure CO2 (Ci), and stomatal conductance (gs) between (09.30 – 11.30 h) on a fully expanded current season leaves situated at mid canopy height. Statistical assessments of differences between mean values were performed by the LSD test at P = 0.05. Results and Discussion The results revealed that reclaimed water enhanced fruit yield, weight (15%), volume (23%) and leaf photosynthesis (22%) in plants compared with clear water. Recycled water was found to supply more nutrients than clear water. High nutrient concentrations in RW, compared to those in clear water, result in nutrient accumulation in the soil, making them available to plant roots to promote overall plant growth and fruit production. Improved N, P, K nutrition of wastewater-irrigated plants has been reported (Farooq et al, 2006). Olive leaves and stems represent storage organs for N and release it in response to the metabolic demands of developing reproductive and vegetative organs (Fernandez-Escobar et al., 2004). However, Al-Abasi et al. (2009) found no statistical differences. Irrigation with SLI systems increased the photosynthesis (33%), and stomatal conductance (57%) when compared with surface irrigation systems. The results showed that reclaimed water had a significant effect on photosynthesis and stomatal conductance. However, fruit length and firmness had no significant difference. Substomatal CO2 decreased when the SI systems were used for irrigation. Also SLI system could enhance fruit yield (65%), weight (17%), photosynthesis (32%) and chlorophyll Fluorescence (Fv/Fm) (18%). The SLI systems with recycled water induced greater shoot growth, total leaf surface area, and transpiration during the entire growing period. This led to an overall positive effect on mean fruit weight and total fruit production per tree. The SLI system applying RW led to more photosynthesis by 34% as compared to the SI system. In the present study, the SLI system delivered water directly in the root zone and improved water availability, which enhanced photosynthetic assimilation rates and plant growth to a great extent. David et al. (2003) showed that subsurface drip irrigation versus other irrigation methods reduced evaporation and improved growth and production in peach trees. Conclusion: As a conclusion, the results from this research show that recycled water could be a promising resource for irrigation of olive trees and acted as a source of nutrients and irrigation water.In addition, SLI irrigation system is more efficient in irrigation of olive trees when compared to surface irrigation system and proved beneficial for olive growth

Relationships between grain protein, Zn, Cu, Fe and Mn contents in wheat and soil and topographic attributes

The knowledge on the relationships of protein and micronutrient concentration in wheat grain with edaphic characteristics could provide valuable information for site specific fertilization of crops for producing grains denser in micronutrients such as iron (Fe) and zinc (Zn) in rainfed agriculture. In this study, we used soil properties and topographic parameters in the artificial neural network (ANN) methodology as power tool for improving models for predicting wheat grain micronutrient and protein contents in the hilly regions of western Iran. Soil and grain samples were collected from 1 m2 plots using stratified random method, whereas the slope positions were considered as the basis of soil sampling, at 100 selected points. The mean grain Zn, Fe, Cu (copper) and Mn (manganese) concentrations were 37.02, 65.86, 14.79 and 44.93 mg-1 kg-1, respectively, and mean grain protein was 13.76%. Application of the ANN models for predicting of Zn, Fe, Cu, Mn and protein contents in grains improved prediction 96.77, 95.45, 124.13, 125 and 109.75 %, respectively, over the multiple linear regression (MLR) models. The topographic parameters wetness index, plan curvature and shaded relief, and the selected soil properties total nitrogen (TN), soil organic matter, available phosphorus, and DTPA-extractable micronutrients were identified as the most important parameters for explaining the variability in wheat grain quality at the study area

The Effects of Two Different Deficit Irrigation Managements on the Root Length of Maize

The response of root to water stress is one of the most important parameters for researchers. Study of growth and distribution of root under different irrigation managements helpsresearchersto a better understanding of soil water content, and the availability of water and nutrition in water stress condition. To investigate the effects of four levels of irrigation under two different deficit irrigation managements on the root length of maize, a study was conducted in 2009. Irrigation managements included fixed irrigation interval-variable irrigation depth (M1) and variable irrigation interval-fixed irrigation depth (M2). Maize plants were planted in 120 large 110-liter containers in a strip-plot design in a randomized complete block with three replications. Root data sampling was done after root washing in five growth stages. The results showed that the effect of irrigation levels on root length was significant (

Étude cinématique des événements binaires et ternaires obtenus par bombardement de cibles d'U, Th, Bi, Pb, Au par des deutons de 2,1 GeV

A kinetic study of binary and ternary fission induced by 2.1 GeV deuterons incident on U, Th, Pb, Bi and Au targets has been made by obtaining the geometrical characteristics of events registered in a 4π solid state track detector. Using some hypothesis the distribution of the mass ratios and the total kinetic energy of the fragments were measured. We thus established that part of the binary events whose projected angles on the plane perpendicular to the incident deuteron differ by 180° arise from the same type of disintegrations as the ternary events. The analytical determination of the ternary events also shows an analogy with the tripartition of heavy nuclei such as for example californium and can also explain the production of part of the heavy and light neutron deficient isotopes, which the radiochemists attribute to fragmentation.Une étude cinématique de la fission binaire et ternaire induite par des deutons de 2,1 GeV sur des cibles U, Th, Pb, Bi et Au est réalisée à partir des caractéristiques géométriques des traces des fragments des événements enregistrés dans un détecteur solide de traces en géométrie 4π. Moyennant certaines hypothèses, on établit la distribution en rapport de masse et en énergie des fragments. On a pu mettre en évidence qu'une partie des événements binaires dont l'angle projeté sur le plan perpendiculaire à la trajectoire de la particule incidente est différent de 180°, procèdent d'un même type de désintégration que les événements ternaires. De même, l'analyse cinématique des événements ternaires montre une certaine analogie avec le phénomène connu de la tripartition de noyaux lourds comme le californium par exemple, et pourrait expliquer la production d'une partie des isotopes légers et lourds déficients en neutrons attribués à de la fragmentation par les radio-chimistes

Regional Frequency Analysis of Drought Severity of SEI-SRI and SEI-SSI Indices in Common Duration Using Multivariate L-Moments and Copula Functions (Case Study: Karkheh River Basin)

Investigation of homogeneity regions using univariate characteristics is an important step in the regional frequency analysis method. However, some hydrological phenomena have multivariate characteristics that cannot be studied by univariate methods. Droughts are one of these phenomena their definition as univariate will not be effective for risk assessment, decision-making, and management. Therefore, in this study, the regional frequency analysis of drought was studied in multivariate methods using SEI (Standardized Evapotranspiration Index), SSI (Standardized Soil Moisture Index), and SRI (Standardized Runoff Index) indices in the Karkheh River basin from 1996 to 2019. The indices calculated probabilistic distribution between the variables of evapotranspiration, runoff, and soil moisture using multivariate L-moments method and Copula functions and considered meteorological, agricultural, and hydrological droughts simultaneously. The results of multivariate regional frequency analysis considering the Copula Gumbel as the regional Copula showed that the basin is homogeneous in terms of severity of SEI-SSI combined drought indices and is heterogeneous in terms of severity of SEI-SSI combined drought indices. However, after clustering the basin into four homogeneous areas in terms of characteristics of SPI (Standardized Precipitation Index), the basin is homogeneous in all areas in terms of univariate SEI, SSI, and SRI indices and is heterogeneous in the third and fourth clusters of SRI and SSI drought indices. Pearson Type (III), Pareto, normal, and general logistics distribution functions were found suitable to investigate the characteristics of SEI, SSI, and SRI drought indices in this case. Finally, large estimates of the types of combined droughts and their probability of occurrence showed that the northern and southern parts of the Karkheh River basin will experience short and consecutive droughts in the next years. Droughts in areas without meteorological data can be predicted in terms of joint probability using the multivariate regional frequency analysis method proposed in this study