Analytic Representation of the Optimal Flow for Gravity Irrigation

The aim of this study is the deduction of an analytic representation of the optimal irrigation flow depending on the border length, hydrodynamic properties, and soil moisture constants, with high values of the coefficient of uniformity. In order not to be limited to the simplified models, the linear relationship of the numerical simulation with the hydrodynamic model, formed by the coupled equations of Barré de Saint-Venant and Richards, was established. Sample records for 10 soil types of contrasting texture were used and were applied to three water depths. On the other hand, the analytical representation of the linear relationship using the Parlange theory of infiltration proposed for integrating the differential equation of one-dimensional vertical infiltration was established. The obtained formula for calculating the optimal unitary discharge is a function of the border strip length, the net depth, the characteristic infiltration parameters (capillary forces, sorptivity, and gravitational forces), the saturated hydraulic conductivity, and a shape parameter of the hydrodynamic characteristics. The good accordance between the numerical and analytical results allows us to recommend the formula for the design of gravity irrigation.

Effect of gripping conditions and strip oscillations on vibrations originating at cold rolling

The process of continuous rolling is subjected to non-stationarity, accompanied by oscillations of not only basic technological and power parameters, but also parameters in the hearth of deformation. Non-stationarity at the rolling accounting high dynamic of the process results in origination of negative vibration effects. To prevent the vibrations originations the rolling speed is decreased, which prevents the reaching of the designing parameters of rolling mills operation. The study of influence of non-stationarity of the rolling technological process on gripping conditions and origination of dangerous oscillations was carried out. Characteristics of rolling mode of strip of 2.0–0.45 × 970 mm dimension, accompanied by vibration was presented, as well as graphs of the strip oscillations in the process of stationary rolling and under conditions of vibrations origination presented. An assumption made, that during vibrations origination the gripping conditions of the strip by rollers are disturbed. It means that provision of the grip stationarity will decrease the risk of the vibrations originating at the rolling. The assumption was confirmed by the studies of the cold rolling at five-stand mill 1700 of Cherepovets steel-works. The calculations of the hearth of deformation parameters were made by application of an elaborated dynamic model of the rolling process. The higher probability of vibrations originating at the rolling of strips of smaller thickness explained. It was shown, that due to the strip length, the rolling of the thinner metal is accomplished at higher speeds, comparing with the rolling of thicker metal. In addition, it was shown that the friction coefficient value at that would promote increase of risk of non-stationary rolling mode originating. The support of stable friction conditions in the hearth of deformation is promoted by usage of chrome-plated working rollers and asymmetrical rolling.

A Tunable Plasmonic Refractive Index Sensor with Nanoring-Strip Graphene Arrays

In the present study, we design a tunable plasmonic refractive index sensor with nanoring-strip graphene arrays. The calculations prove that the nanoring-strip have two transmission dips. By changing the strip length L of the present structure, we find that the nanoring-strip graphene arrays have a wide range of resonances (resonance wavelength increases from 17.73 μm to 28.15 μm). When changing the sensing medium refractive index nmed, the sensitivity of mode A and B can reach 2.97 μm/RIU and 5.20 μm/RIU. By changing the doping level ng, we notice that the transmission characteristics can be tuned flexibly. Finally, the proposed sensor also shows good angle tolerance for both transverse magnetic (TM) and transverse electric (TE) polarizations. The proposed nanoring-strip graphene arrays along with the numerical results could open a new avenue to realize various tunable plasmon devices and have a great application prospect in biosensing, detection, and imaging.

Design a Vegetative Filter Strips Length Using VFSMOD_W Model for Reducing Sediments and Pesticides

The vegetative filter strips (VFS) are a useful tool used for reducing the movement of sediment and pesticide in therivers. The filter strip’s soil can help in reducing the runoff volume by infiltration. However, the characteristics of VFS (i.e., length) are not recently identified depending on the estimation of VFS modeling performance. The aim of this research is to study these characteristics and determine acorrelation between filter strip length and percent reduction (trapping efficiency) for sediment, water, and pesticide. Two proposed pesticides(one has organic carbon sorption coefficient, Koc, of 147 L/kg which is more moveable than XXXX, and another one has a Koc of 2070 L/kg which is less moveable than XXXX) are presented, where the goal is to prevent 95% of incoming sediment and 85% of the incoming pesticide to reach a receiving stream in still water, Oklahoma from a cultivated field (1250 m²),for 2 hour storm with 5 years return period. Several VFS lengths were simulated including1, 3, 5, 6, 9, 11, 12, and 13 m. The results showed that the percent of reduction of sediment, pesticide, and water mainly depends on VFS lengths. Moreover, considering the design storms range, the simulation illustrated that the optimal filter length was13m for silty clay loam. When the value of was increased from 147 L/kg to 6070 L/kg, the filter length decreased from 13 to 9.5 because of the increase in trapping efficiency. In addition, the results revealed that the trap­ping efficiency was for sediment but not for water orpesticide which was highly impacted by the narrow filter strips. The amount of the rainfall and runoff of the designated field was larger than the infiltration capacity of filter strips, which resulted in low trapping efficiency for pesticide and water. Keywords: Models ,runoff, sediment, vegetative filter strip, , water quality, watershed planning.

Deformation Behavior of Reinforced Concrete Two-Way Slabs Strengthened with Different Widths and Configurations of GFRP

In this paper, we conducted a numerical analysis of the deformation behavior of Steel-reinforced concrete (RC) two-way slabs strengthened by glass fiber reinforced polymer (GFRP) with different widths and configurations. A total number of 36 RC slabs of cm were used in this numerical study. Also, a column of was considered in the center of the slab for applying static loading. The bonded GFRP strips had 5, 7.5 and 10 cm width (W) and configured in three models called PM1, PM2, and DM. In PM1 (strip length = 2.4 m) and PM2 (strip length =1.7 m) configurations, the strips were bonded in two directions parallel to the sides of the slab, while in DM configuration (strip length =1.7 m), strips were rotated with 45 degree angle around the central axis that is perpendicular to the surface of the slab. According to the comparison results, we found out that the 5-cm wide strips with PM1 configuration having a parallel space of 0.5 times the strip width ( ) greatly reduced the deformation of RC two-way slab compared to other strip widths and configurations, while strips under all configurations, highly increased the deformation when space between strips varied from to .

Numerical Investigation of a Process Control for the Roller Levelling Process Based on a Force Measurement

When processing conventional semi-finished metal strips, distinctive changes in the material properties along the strip length are unavoidable. The roller levelling process is sensitive to changes of those strip characteristics. Thus, a process control allowing for an online adaption of the roller levelling machine according to the actual strip characteristics is highly desirable. In order to enable a precise process layout, the calculation by the Finite Element Method (FEM) provides a suited strategy. Furthermore, the coupling of user-subroutines to an FE code offers the possibility to implement and test respective control strategies. This work proposes a control strategy that is based on a force measurement in the first load triangle of a levelling machine. A first FE model including a feedback control is used to calculate the dependence between the force in the first load triangle and the roll intermesh in the last load triangle leading to a flat sheet. The results are transferred to meta models – so called control curves – that give a direct relationship between the measured force and the roll intermesh. Within a second FE setup a feed-forward control based on these control curves is implemented and the proposed control strategy is investigated for varying yield strengths along the strip length. Thus, the time consuming FE simulations that are necessary to obtain the control curves are decoupled from the actual levelling process. According to the obtained results, the introduced approach is able to improve the sheet flatness for thin sheets when a change in the material properties occurs.

Design of Elastic Element and Controller Algorithm

Recent development of series elastic actuators have revealed a capability to mimic muscle-like properties and achieve accurate force control. Series elastic actuators have also been widely used in humanoid and surgical robotic devices. The design of the elastic elements are critical and complex. This tends to increase costs and complexity of designing and controlling series elastic actuators. Here, we present a novel low cost and easy-to-fabricate design for a series elastic element that also has adjustable stiffness. The design consists of simple shaft couplers and spring steel plates. During the test, the stiffness of the designed elastic elements is very close to linear (R2 = 0.999) when the clamped spring-steel strip length is sufficiently long. As the clamped strip length shortens, the resulting torque deflection curve becomes slightly quadratic but remains largely linear. Also, the designed elastic element exhibits little hysteresis during loading and unloading. The stiffness of the designed elastic element can be tuned to achieve a range of stiffness values, thus it is suitable for different applications with different stiffness requirements. We also design a simple control algorithm and develop a simulation based on the dynamic properties of the designed elastic element. In simulation, the controller is able to accurately track the commanded torque values. Overall, this design could help reduce the cost and development time required for series elastic actuators.