Adaptive wavenet controller design for teleoperation systems with variable time delays using singular perturbation method

The main goal of controller design in teleoperation systems is to achieve stability and optimal operation in presence of factors such as time delays, system disturbances and modeling errors. This paper proposes a new method of controller design based on wavenet with singular perturbation method for the bilateral teleoperation of robots through the internet. The wavenet controller could overcome the variable time delay in teleoperation system. This new method introduces a reduced-order structure for control and stability of teleoperation systems. By using singular perturbation method, teleoperation system is decomposed into two fast and slow subsystems. This method is a step towards reduced-order modeling. In this method, we use a feedback linearization method in master subsystem and a wavenet controller for slave subsystem. In wavenet controller, we used a learning method so that the system was Lyapunov stable. As the stability of the model is highly dependent on the learning of the system, we use Lyapunov stability in this method. It has been tried to reduce the tracking error between the master and the slave subsystems. In this structure the position of master-slave are compared together and controlling signal is applied to the slave so that they can track each other in the least possible time. In all schemes the effectiveness of the system is shown through the simulations and they have been compared with each other.     

Ion-crosslinked carboxymethyl cellulose/polyaniline bio-conducting interpenetrated polymer network: preparation,characterization and application for an efficient removal of Cr(VI) from aqueous solution

A simple, cheap, and environmentally friendly bio-conducting interpenetrated polymer blend network was prepared and introduced as a highly efficient system with suitable physical and mechanical properties for industrial removal of toxic Cr(VI) ions from aqueous solution. Carboxymethyl cellulose/polyaniline (CMC/PANI) interpenetrated network (IPN) blend was prepared by simple simultaneous ion-cross-linking of CMC and PANI chains using Al³⁺ cations. The CMC/PANI bio-conducting nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy equipped with an "energy dispersive X-ray spectroscopy" (SEM–EDX) technique. The CMC/PANI blend, ion-cross-linked by Al³⁺ cations, showed good stability and high surface area, proper for the removal of toxic Cr(VI) ions of the aqueous solution. Batch removal experiments were accomplished and the impression of effective variables including solution pH, initial concentration of Cr(VI) ions, contact time, and adsorbent dosage were checked and optimized. The outcome of our findings revealed that the removal of Cr(VI) ions by CMC/PANI nanocomposite IPN strongly depends on solution pH. The removal information was matched with the Langmuir adsorption isotherm model and the utmost monolayer adsorption capacity at pH 2 was 136.98 mg/g at 25 °C. The pseudo-second-order kinetics were operated and the thermodynamic parameters suggested spontaneous and exothermic nature of the adsorption process. Consequences indicated that CMC/PANI nanocomposite IPN could be an affective eco/environmentally friendly adsorbent for the removal of Cr(VI) ions from aqueous solutions.

     

Tuning the curing behavior of fluoroelastomer (FKM) by incorporation of nitrogen doped graphene nanoribbons (CNx-GNRs)

Graphene nanoribbons (GNRs), obtained by different methods from carbon nanotubes (CNTs) or graphene, are attractive materials for polymer nanocomposites due to their considerably high interfacial area, as compared to CNTs. Consequently, a better adhesion with a polymer matrix is anticipated for GNRs. Also, surface modification of these nanofillers, such as nitrogen doping, is known to be an efficient method to improve their properties. In this work, fluoroelastomers (FKM) were used as the polymer matrix to host GNRs. Undoped and nitrogen doped GNRs were synthesized from the parent multiwall carbon nanotubes (MWCNTs). MWCNT/FKM and GNR/FKM nanocomposites were prepared via a solution mixing/melt mixing protocol.     

Enhancement of discharged energy density of poly(ethylene oxide) by soy protein isolate

Soy protein isolate (SPI) is used to modify energy storage performances of poly(ethylene oxide) (PEO). The pure PEO membranes are highly polar, but the extremely high energy loss led to very low discharged energy density for use. The addition of SPI in both high molecular weight PEO and low molecular weight PEO lead to greatly reduced polarization and stored energy density. However, it also largely reduces the current leakage and energy loss of the resulting membranes, leading to significantly enhanced discharged energy density. It is believed that the strong interactions between PEO and SPI are responsible for the energy storage properties aforementioned. Meanwhile, such interactions also result in a more brittle fracture behavior and reduced crystallinity of the PEO/SPI membranes. The enhanced discharged energy density and low energy loss suggest PEO/SPI membranes are promising dielectric materials for high efficiency energy storage applications where soluble and transient materials are desired. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45214.     

A Method for the Estimation of the Interface Temperature in Ultrasonic Joining

Ultrasonic joining of copper foil to 1100 aluminum sheet at nominal joining temperatures of 298 K to 413 K (25 °C to 140 °C) for 1.25 second caused significant copper diffusion into the aluminum sheet, indicating very high diffusivity (D) values of 1.54 × 10^?13 to 2.22 × 10^?13 m²/s. The D values reflect high excess vacancy concentrations caused by the rapid plastic deformation in the joining surfaces. A method is presented to estimate the actual values of interface temperature from the diffusion data and expected values of vacancy concentrations. The estimated values of interface temperature were about 390 to 410 deg below the equilibrium melting point of aluminum, and in agreement with reported experimental values.     

A decision support system for fuzzy multi-objective multi-period sustainable project selection

In this paper, a Decision Support System (DSS) is developed to solve sustainable Multi-Objective Project Selection problem with Multi-Period Planning Horizon (MOPS-MPPH). First, a TOPSIS based fuzzy goal programming (FGP) is proposed which considered uncertain DM preferences on priority of achievement level of fuzzy goals. The FGP essentially considers economic factors like cost, profit, and budget. The output of FGP and other affecting factors (i.e. social and environmental effects, risk of investment, strategic alliance, and organizational readiness) are treated as inputs of a fuzzy rule based system to estimate fitness value of an investment. Properties of the proposed DSS are discussed. It also is compared with an existing procedure on historical data of a financial and credit institute.     

Compressive estimation for signal integration in rendering

In rendering applications, we are often faced with the problem of computing the integral of an unknown function. Typical approaches used to estimate these integrals are often based on Monte Carlo methods that slowly converge to the correct answer after many point samples have been taken. In this work, we study this problem under the framework of compressed sensing and reach the conclusion that if the signal is sparse in a transform domain, we can evaluate the integral accurately using a small set of point samples without requiring the lengthy iterations of Monte Carlo approaches. We demonstrate the usefulness of our framework by proposing novel algorithms to address two problems in computer graphics: image antialiasing and motion blur. We show that we can use our framework to generate good results with fewer samples than is possible with traditional approaches.     

Effect of different precooking methods on chemical composition and lipid damage of silver carp (Hypophthalmichthys molitrix) muscle

The influence of three precooking methods (steaming, oven‐baking and microwave‐cooking) on the chemical composition and lipid quality of silver carp fillets was evaluated. The changes in protein, fat and moisture were found to be significant for all the treatments (P ≤ 0.05). The iron content in the samples subjected to steam‐cooking increased; however, the other precooking methods did not change the mineral contents (P ≥ 0.05). The free fatty acid content of the fillets did not change by the different precooking methods, while thiobarbituric acid (TBA) values increased for oven‐ and microwave‐cooked fillets and remained constant in the steam‐cooked samples. Conjugated diene and browning colour formation levels significantly increased in the oven‐baked fillets. Oven‐baking and microwave‐cooking marginally affected the fatty acid composition of the silver carp. On comparing the raw and precooked fillets, steam‐cooking was found to be the best precooking method on retaining nutritional constituents.     

Numerical solution of stokes flow in a circular cavity using mesh-free local RBF-DQ

This work reports the results of a numerical investigation of Stokes flow problem in a circular cavity as an irregular geometry using mesh-free local radial basis function-based differential quadrature (RBF-DQ) method. This method is the combination of differential quadrature approximation of derivatives and function approximation of Radial Basis Function. As a result, the method can be used to directly approximate the derivatives of dependent variables on a scattered set of knots. In this study knots were distributed irregularly in the solution domain using the Halton sequences. The method is applied on a two-dimensional geometry. The obtained results from the numerical simulations are compared with those gained by previous works. Outcomes prove that the current technique is in very good agreement with previous investigations and this fact that RBF-DQ method is an accurate and flexible method in solution of partial differential equations (PDEs).