In this study, a two-dimensional hydrodynamic model was developed using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) to evaluate notch impacts on water levels and sedimentation processes. The study site includes an approximately 2-mi stretch of the Missouri River with a dike field, including eight spur dikes with notches and three spur dikes without notches. Elevation contours of the existing condition digital terrain model were modified by performing geospatial operations in the vicinity of each notch to create two additional terrain conditions—proposed conditions 1 (filled notches with filled scour holes downstream of each notch) and proposed conditions 2 (filled notches with existing scour holes downstream of each notch). Four flow events were modeled at each terrain condition to account for different dike overtopping ratios. The model results of each proposed condition were compared with the existing condition near the dike, at the downstream riverbank, and at the navigation channel for each notched dike. Results indicated that filling the notch and scour hole causes higher degradation rates in the navigation channel, decreased bank scour downstream of each notch, and high variability in hydraulic stresses on the dike structures.

This study focuses on the prediction of the porosity of nonuniform sediment mixtures, considering the effects of particle packing. A random particle packing model has been developed for the porosity of bimodal mixtures by extending the existing random particle filling theory. Coefficients in the developed model are calibrated by fitting the model to measured data for a variety of bimodal mixtures, including spherical glass particles, rounded quarry grains, and natural sediments. The model coefficients are found to be functions of the diameter ratio of coarse and fine particles, separately for spherical glass particles and natural sediments due to differences in particle shapes. The bimodal mixture model is then extended to trimodal particle mixtures in three approaches: two based on serial packing and one based on random packing. These models are tested against experimental data of six trimodal mixtures with spherical glass beads. The results show that the random packing model and the fine–medium–coarse particle serial packing model predict well the observed trimodal mixture porosities.

cm, cs = cohesion of muddy clay and silty clay (kPa) ds = median diameter of cohesionless soil (mm) d50 = median diameter of soil (mm) I P = plasticity index ( − ) pm = fraction of mud in the sediment mixture ( − ) R2 = coefficient of determination ( − ) WL = liquid limit ( − ) Wp = plastic limit ( − ) ρd = dry density of the sediment mixture (kg m−3) τ c = critical shear stress of soil (Pa) τ cm,τ cs = critical shear stress of muddy clay and silty clay (Pa)

Erosion of mixed cohesive and noncohesive sediments is studied using the erosion test instrument SEDFlume.The sediment mixtures are composed of well-sorted quartz sand(0.25-0.5 mm) and one of the three used muds:kaolinite,kaolinite-bentonite and Mississippi River muds.The mud contents cover from 0 to 100%.The measured data of erosion rate and bed shear stress are used to examine the segmented linear,nonlinear,and exponential erosion models.The parameters of each erosion model are related to the physical properties of sediment mixtures,including clay fraction,mud fraction,mixture dry density,and mud dry density.It is found that the three models can fit well with the data,and their parameters have strong relations with the mud fraction and mud dry density,to a less extent with the clay fraction,but not with the mixture dry density.

This paper presents a methodology to harvest the kinetic energy of the raindrops using piezoelectric devices. In the study 1m×1m PVDF (Polyvinylidene fluoride) piezoelectric membrane, which is fixed by the four edges, is considered for the numerical simulation on deformation of the membrane due to the impact of the raindrops. Then according to the drop size of the rain, the simulation is performed classifying the rainfall types into three categories as light stratiform rain, moderate stratiform rain and heavy thundershower. The impact force of the raindrop is dependent on the terminal velocity of the raindrop, which is a function of diameter. The results were then analyzed to calculate the harvestable energy from the deformation of the piezoelectric membrane. Keywords—Raindrop, piezoelectricity, deformation, terminal velocity.

The critical shear stress for erosion of sand and mud mixtures is theoretically investigated and expressed as a function of the critical shear stresses of pure sand and mud, mud content, and sand diameter. The proposed formula accounts for different structures and behaviours of the mixtures with low and high mud contents. The critical shear stress of pure mud is related to the solid/void volume ratio, and this relation is extended to the mud component in the mixture to consider the effect of compaction. It is found that the mud dry density, not the mixture dry density, is a direct factor affecting the mixture erosion. The developed formula has been calibrated and tested using four sets of experimental data collected from the literature. It reproduces the variations of the critical shear stress and mud dry density well.

Developing methods to quantify erosion dynamics of cohesive sediments is challenging due to the complexity of many physical, chemical, and biological processes involved. Even though several empirical formulas were introduced in literature to calculate the erosion rate of cohesive sediments, there are still substantial uncertainties in determining the erosion coefficients. In this study, the relationships of erosion coefficients with sediment properties have been investigated. First, the erosion coefficient in the linear erosion formula is found to be a function of the critical shear stress based on a large number of measurement data from literature. Then, an existing empirical formula is tested to predict the erodibility coefficient when the clay percentage and dry specific weight of soil are given. Finally, the critical shear stress of cohesive soils is related to the dry density and solid-void volume ratio by using measurement data.

— In this paper the design, development and testing of a stabilizer control system for a Quad-rotor is presented which is focused on the maneuverability. The mechanical design is performed along with the design of the controlling algorithm which is devised using fuzzy logic controller. The inputs for the system are the angular positions and angular rates of the Quad-rotor relative to three axes. Then the output data is filtered from an accelerometer and a gyroscope through a Kalman filter. In the development of the stability controlling system Mandani fuzzy model is incorporated. The results prove that the fuzzy based stabilizer control system is superior in high dynamic disturbances compared to the traditional systems which use PID integrated stabilizer control systems.

Precision agriculture is combined with irrigation control systems to observe the environment and respond accordingly. In this paper, we discussed developmental procedure of a novel irrigation control system called Sensor Based Self-powered Smart Irrigation Control System (SSSICS). In the current market, there are several irrigation controllers available and they are either timer based open loop (OL) or sensor-based closed loop (CL) irrigation controllers. Each method has different advantages and disadvantages, and SSSICS contains OL and CL control techniques to get rid of disadvantages. We used OL control technique to work in the Timer Mode(TM) and CL control technique to work in the Intelligent Mode (IM). We introduced a new graphical user interface (GUI) as a human-machine interface (HMI). This HMI and available inputs facilitated the farmer to set precise environmental parameters required for the crop to give maximum yield. For remote farm fields, it is necessary to have a remote communication (RC) and uninterrupted power supply. Text messages that receive and send via Global System for Mobile (GSM) Communication allow the farmer/user to perform RC with the control system (CS) of the SSSICS. We designed a Micro Hydro Power Generator (MHPG) array and solar system including rechargeable batteries to give the power required to the SSSICS. The SSSICS was tested in real environment and it was demonstrated that hybrid power generation concept by incorporating open loop and closed loop control techniques works properly in the hardware platform developed for the study.