Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album)

Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35kH were applied for 0 (control), 5, 10, 15 and 30 minutes using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared to the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 minutes and seedling length (40%) at 30 minutes compared to the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 minutes had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient non-destructive method to break seed dormancy in common lambsquarters

Accelerating Deep Learning Inference on Mobile Systems

Artificial Intelligence on the edge is a matter of great importance towards the enhancement of smart devices that rely on operations with real-time constraints. We present PolimiDL, a framework for the acceleration of Deep Learning on mobile and embedded systems with limited resources and heterogeneous architectures. Experimental results show competitive results with respect to TensorFlow Lite for the execution of small models

Composite patch reinforcement of a cracked simply-supported beam traversed by moving mass

In this study dynamic analysis of a metallic beam under travelling mass was investigated. A beam with an edge crack was considered to be reinforced using composite patch. Euler-Bernoulli beam theory was applied to simulate the time-history behavior of the beam under dynamic loading. Crack in the beam was modeled using a rotational spring. Dimension of the composite patch, crack length, stress intensity factor at crack tip and beam deflection are some parameters which were studied in details. Results were validated against those which were found through Finite Element Method

A fast adaptive PD-FEM coupling model for predicting cohesive crack growth

In this study, nonlocal theory of peridynamic (PD) is coupled with finite element method (FEM) to simulate cohesive crack growth in quasi-brittle materials. The adaptive dynamic relaxation method is adopted to implement quasi-static loading conditions. The advantage of peridynamic method in the modeling of crack propagation is taken into consideration to be coupled with that of finite elements which is computationally less expensive and covers various boundary value problems. In this novel method, the whole domain of the problem is initially dominated by FEM solver with coarse mesh grids. Coupling process is then introduced to those regions which have critical conditions according to damage criterion. The capability of the proposed coupling method in the modeling of cohesive crack growth in quasi-brittle materials is demonstrated. In comparison to other conventional PD-FEM coupling methods, the computational cost of the proposed method is considerably improved and total running time of the solution is significantly attenuated. The validity of the method is confirmed through comparing the results with experimental ones.(c) 2023 Elsevier B.V. All rights reserved

Assessment of Performance the Recorded Herbicides in Rice (Oryza sativa) to Control Weed Species in Raton

This experiment was conducted to evaluate the performance of different herbicides on weed control and yield of ratoon rice as a randomized complete block design with four replications during 2012 at the Pasha Cola village of Sari- Iran. The treatments were: Anilofos+ Ethoxysulfuron (3 lit ha-1), Butachlor (3 lit ha-1) + Cinosulfuron (100 g ha-1), Bensulfuron methyl (75 g ha-1) + Butachlor (3 lit ha-1), Butachlor (3 lit ha-1), Cinosulfuron (100 g ha-1), Bensulfuron methyl (75 g ha-1) with a two-step weeding and weedy treatment (control). Results showed that the Sulfonylurea group herbicides such as Cinosulfuron and Bensulfuron methyl reduced density and dry weight of weed on the one hand and density and dry weight of weed in total on the other hand during the growing season. This leads to increase in ratoon rice yield at the end of the growing season. In addition to results showed that the Butachlor does not affected density and dry weight of weeds it caused reduction in weight of 1000 grain and yield of ratoon rice

Crack propagation modeling using Peridynamic theory

Crack propagation and branching are modeled using nonlocal peridynamic theory. One major advantage of this nonlocal theory based analysis tool is the unifying approach towards material behavior modeling- irrespective of whether the crack is formed in the material or not. No separate damage law is needed for crack initiation and propagation. This theory overcomes the weaknesses of existing continuum mechanics based numerical tools (e.g. FEM, XFEM etc.) for identifying fracture modes and does not require any simplifying assumptions. Cracks grow autonomously and not necessarily along a prescribed path. However, in some special situations such as in case of ductile fracture, the damage evolution and failure depend on parameters characterizing the local stress state instead of peridynamic damage modeling technique developed for brittle fracture. For brittle fracture modeling the bond is simply broken when the failure criterion is satisfied. This simulation helps us to design more reliable modeling tool for crack propagation and branching in both brittle and ductile materials. Peridynamic analysis has been found to be very demanding computationally, particularly for real-world structures (e.g. vehicles, aircrafts, etc.). It also requires a very expensive visualization process. The goal of this paper is to bring awareness to researchers the impact of this cutting-edge simulation tool for a better understanding of the cracked material response. A computer code has been developed to implement the peridynamic theory based modeling tool for two-dimensional analysis. A good agreement between our predictions and previously published results is observed. Some interesting new results that have not been reported earlier by others are also obtained and presented in this paper. The final objective of this investigation is to increase the mechanics knowledge of self-similar and self-affine cracks.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Wave propagation improvement in two-dimensional bond-based peridynamics model

In this study, methods to mitigate anomalous wave propagation in 2-D Bond-Based Peridynamics (PD) are presented. Similarly to what happens in classical non-local models, an irregular wave transmission phenomenon occurs at high frequencies. This feature of the dynamic performance of PD, limits its potential applications. A minimization method based on the weighted residual point collocation is introduced to substantially extend the frequency range of wave motion modeling. The optimization problem, developed through inverse analysis, is set up by comparing exact and numerical dispersion curves and minimizing the error in the frequency-wavenumber domain. A significant improvement in the wave propagation simulation using Bond-Based PD is observed

Evaluating Rimsulforon Efficiency on Controlling Weeds in Potato at Different Growth Stages

Introduction Potato is globally the fourth important food crop after rice, wheat, and maize and is cultivated in several countries worldwide like Iran. Weeds are the most important restriction factor for crop development in agricultural systems and the absence of weed control lead to crop yield reduction between 10 to 100 percent and this reduction could be a serious threat for a growing world population to be considered. Rimsulfuron is a sulfonylurea herbicide for control of weeds in potato, corn, wheat, barley and canola. It can be used as pre or post emergence in potato. These herbicide act through inhibition of enzyme acetolactate synthase (ALS), which catalyzes key reactions in the biosynthesis of basic branched-chain amino acids that are essential components of the growth process in plant cell division such as valine, leucine, and isoleucine Materials and methods In order to study rimsulfuron (Titus 25% DF) effect on weed biomass as a postemergence herbicide, a field experiment was carried out in the farm located 3 km out the city of Ardabil during 2014. The factorial experiment was performed based on randomized complete block design with three replications. Potato cultivar was Agria (common cultivar in Ardabil). The first factor was rimsulfuron doses with six levels (5, 10, 20, 30, 40 and 50 gr a.i. / ha), and the second factor was time of application based on different potato growth stages, (Potato emergence, stoloning and tuber bulking). Also two treatment (with and without weeding) were considered as control. Tubers were hand sown on 22th May in rows 75 cm apart and 20 cm in the rows at 10 cm depth. Rimsulfuron was applied by backpack sprayer fitted with 8001 flat fan nozzles. Three weeks after treatment, weed sampling was carried out by a quadrate sized 0.375 m2. Tubers were harvested from two center rows to determine total tuber yield per hectare. Two models fitted to the data were three parameter logistic and three parameter sigmoid. Data were analyzed using SAS 9.1 and MSTAT-C. Analysis of variance was used to test the significance of variance sources, and Duncan’s Multiple range test (P ≤ 0.05) was used to compare the differences among treatments. Results and Discussion Results showed that the maximum reduction percent of redroot pigweed (Amaranthus retroflexus L.), field bind weed (Convolvulus arvensis L.), lambsquarter (Chenopodium album L.), total weed biomass and density achieved by 40 and 50 gr a.i. / ha application. So that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced weed density up to 49.47and 55.38 % and biomass up to 89.97 and 94.63 %, respectively. Also results showed that 40 and 50 gr a.i. /ha of rimsulfuron compared to control reduced biomass of redroot pigweed 89.91 and 95.50 %, Field bind weed 84.28 and 94.79 % and lambsquarter 92.75 and 96.87 percent respectively. That there was not statistically significant difference between 40 and 50 gr a.i. /ha of rimsulfuron. Among rimsulfuron application times, potato emergence stage reduced total weed density and biomass 36.45 and 68.04 %, respectively which is compared to control (weedy). Rimsulfuron application at potato emergence stage reduced biomass of redroot pigweed and lambsquarter 62.51 and 71.08 percent respectively. However it had no significant effect on biomass of Field bind weed. The results showed that potato tuber yield was 46.31 and 45.96 ton/ ha while rimsulfuron applied 40 and 50 gr a.i. / ha. Among rimsulfuron application times, potato emergence stage had total tuber yield 47.58 ton/ha. Conclusion Results showed that the maximum reduction percentage in weed density and biomass was observed for treatments in which were used 40 and 50 gr a.i. / ha application. Application of rimsulfuron at potato emergence reduced weed density and biomass and increased total tuber yield. Itproves the effectiveness of the rimsulfuron for potato emergence without damage. Furthermore the effective dose of rimsulfuron for 50 percent reduction in biomass of redroot pigweed, field bind weed and lambsquarter were 14.36, 12.26 and 10.17 g a.i. /ha, respectively. The results also showed that rimsulfuron application 40 and 50 gr a.i. /ha increased total tuber yield by 19.90 and 20.51% respectively. Application of 40 and 50 gr a.i. / ha at potato emergence stage produced maximum total tuber yield per hectare. The result of this study showed that 40 and 50 gr a.i. /ha rimsulfuron application at potato emergence assessed as the best treatment to control weed and increase total yield

Predicting Emergence of the Most Important Weed Species in Soybean (Glycine max L.) under Different Management Operation

Introduction: Summer annual weeds typically germinate in spring and early summer, grow throughout the summer, and set seeds by fall. Summer annual weeds are a persistent problem in summer annual row crops, competing directly for water, light, and nutrients, causing yield losses in quantity and quality. Although agriculture is increasingly relying on modern technology, knowledge of the biological systems in which these technologies are used is still critical for implementation of management strategies. Biological information about weeds is valuable and necessary for developing management strategies to minimize their impact. Scouting fields for pest problems are essential in any cropping system and knowledge of the timing and sequence of weed species emergence could increase the effectiveness of weed scouting trips and subsequent management practices. The success of any annual plant is directly correlated to its time of seedling emergence because it determines the ability of a plant to compete with its neighbors, survive biotic and abiotic stresses, and reproduce. The period and pattern of emergence of the weed community depend on the species present in the seed bank and their interaction with the environment. Therefore, knowledge of the weed species present in the soil seed bank and when these species are most likely to emerge is important in planning effective weed control programs. Temperature has been reported to be the main environmental factor regulating germination and emergence of weed species. Scientists have developed TT models to predict the emergence of weed species based on a daily accumulation of heat units or growing degree days (GDD) above a minimum base threshold value (Tbase). The predictive models for weed emergence based on the accumulation of TT appear to be accurate enough for projections of weed emergence time (Grundy 2003). Moreover, soil temperature data are easily accessible, making this type of model practical and useful to farmers. Many studies of weed growth, and thus predicting models for areas outside of Mazandaran is performed as a particular study. Because the differences in soil conditions, climatic, geographic and weed species there is a possibility that these models are not appropriate to predict weed species in Mazandaran province. Furthermore, the purpose of this experiment is investigation growth of weeds and develops an empirical model based on GDD to predicting the growth of several species of summer weeds in soybean. Materials and methods: The experiment was conducted as split split-plot in a randomized complete block design with three replications in the summer of 2016 in Dasht-e-Naz Company Sari-Iran with geographical coordinates 36º 39´ N 53º 11´ E, and 1 meters above sea level. The treatments included two tillage system (No Tillage, Tillage), three densities of 20, 30 and 40 plants per square meter of soybeans and Pursuit-doses (imazethapyr) (0, 50%, 75%, standard dose and 25% of the standard dose, respectively). To predict the growth pattern in each plot a fixed 50 × 50 cm quadrat fixed in the center of each plot and since the beginning of the season and after the first irrigation, counting of new grown seedlings was began based on weeds species. The Counting was performed weekly and then counted seedlings were eliminated after in any stage as long as new emergence was not seen. Non-linear regression (Sigma Plot 12.5) was used for the expression pattern of cumulative emergence of seedlings. The 3 parameter logistic function was fitted to the data. where y represents the predicted cumulative percent emergence, X0, GDD to reach the %50 cumulative emergence, a is the upper asymptote (theoretical maximum percent emergence), b is the slope of the curve. We considered that soil water was not a limiting factor for weed emergence, using soil temperature (growing degree days, GDD) as the only independent variable for predicting cumulative emergence. Thus, GDD were calculated with the soil temperatures by using the formula: where Tmax and Tmin are the daily maximum and minimum temperature, respectively, and Tb is the base temperature. Base temperatures used in the calculations of GDD were: 9.0ºC for A. theophrasti, 12.0ºC for S. halepense, 22.3ºC for A. retroflexus, 8.1ºC for E. maculate, 7.5ºC for P. oleracea, 4.0ºC for B. napus. From the emergence count data, mean emergence time (MET) and emergence rate index (ERI) were calculated as follows: where N1, ..., Nn is the number of newly emerged seedlings since the time of the previous count, t1, ..., tn are the GDD after sowing, and n is the number of sampling occasions. These two indices give us a simple indication of the emergence process, providing a useful tool to compare the progress of seedling emergence of each species in the two sites. However, they cannot provide more detailed information on emergence duration and speed. Results and Discussion: The results showed that except sorghum that in tillage treatment had the lowest cumulative emergence, other species in no-tillage treatment had the lowest cumulative emergence. At the end of the sampling patterns of emergence has been specified, all species of weeds, in the density of 40 plants per square meter of soybean and dose of 1.25 liter per hectare of herbicide Pursuit had the lowest cumulative emergence and in the density of 20 plants per square meter of soybean and dose of 0 liters per hectare of herbicide Pursuit had the maximum cumulative emergence. Among other species, Amaranthus retroflexus needed the lowest mean emergence time (MET) and the lowest growing degree days (GDD) to reach 50% emergence. Whereas, among the species, Abutilon theophrasti needed maximum mean emergence time (MET) and maximum growing degree days (GDD) to reach 50% emergence. On this basis, growth stage suitable for controlling pigweed, when the main wave of seedlings of other species still have not found growing. The best management practice used to manage weeds will depend upon the weed species present in the soil seed bank, and diversity of management tactics (e.g., planting dates) will result in fewer shifts in species composition