Transport and deposition of polymer-modified Fe0 nanoparticles in 2-D heterogeneous porous media: effects of particle concentration, Fe0 content, and coatings

Concentrated suspensions of polymer-modified Fe(0) nanoparticles (NZVI) are injected into heterogeneous porous media for groundwater remediation. This study evaluated the effect of porous media heterogeneity and the dispersion properties including particle concentration, Fe(0) content, and adsorbed polymer mass and layer thickness which are expected to affect the delivery and emplacement of NZVI in heterogeneous porous media in a two-dimensional (2-D) cell. Heterogeneity in hydraulic conductivity had a significant impact on the deposition of NZVI. Polymer modified NZVI followed preferential flow paths and deposited in the regions where fluid shear is insufficient to prevent NZVI agglomeration and deposition. NZVI transported in heterogeneous porous media better at low particle concentration (0.3 g/L) than at high particle concentrations (3 and 6 g/L) due to greater particle agglomeration at high concentration. High Fe(0) content decreased transport during injection due to agglomeration promoted by magnetic attraction. NZVI with a flat adsorbed polymeric layer (thickness ～30 nm) could not be transported effectively due to pore clogging and deposition near the inlet, while NZVI with a more extended adsorbed layer thickness (i.e., ～70 nm) were mobile in porous media. This study indicates the importance of characterizing porous media heterogeneity and NZVI dispersion properties as part of the design of a robust delivery strategy for NZVI in the subsurface.     

Inverse problem in optical diffusion tomography. III. Inversion formulas and singular-value decomposition

We continue our study of the inverse scattering problem for diffuse light. In particular, we derive inversion formulas for this problem that are based on the functional singular-value decomposition of the linearized forward-scattering operator in the slab, cylindrical, and spherical geometries. Computer simulations are used to illustrate our results in model systems.     

A voice-activated robot with artificial intelligence

In this paper, a voice activated robot arm with intelligence is presented. The robot arm is controlled with natural connected speech input. The language input allows a user to interact with the robot in terms which are familiar to most people. The advantages of speech activated robots are hands-free and fast data input operations. The proposed robot is capable of understanding the meaning of natural language commands. After interpreting the voice commands a series of control data for performing a tasks are generated. Finally the robot actually performs the task. Artificial Intelligence techniques are used to make the robot understand voice commands and act in the desired mode. It is also possible to control the robot using the keyboard input mode.     

Matrix representation of a “Staran” interconnecting network

The design of a concurrent or multiprocessing system is usually confronted with the task of analysis and the design of a suitable interconnecting network. To make the analysis easy, a matrix representation has been proposed for a “Staran” interconnecting network, which forms the basis of many other interconnecting networks currently being used. The matrix representation not only simplifies the analysis but is very handy for the fault diagnosis and generalisation of higher order networks. The representation proposed for a 2-stage network is extended for 3-stage network and subsequently an algorithm has been presented for higher order networks.     

Decentralized robust controller design for a class ofinterconnected uncertain systems: with unknown bound of uncertainty

In this paper, a simple decentralized robust control scheme is proposed for a class of interconnected time-varying systems with uncertainties. The uncertainties may appear in the interconnections between the subsystems and also within the subsystems, and they are possibly nonlinear and time-varying. The uncertainties are bounded, but the bounds of the uncertainties are unknown in controller design. When certain matching conditions are satisfied for the uncertain interconnections and the uncertainties within the subsystems, the proposed decentralized control scheme guarantees the controlled system to converge exponentially with a prescribed degree toward the equilibrium of the system, or a residual ball around the equilibrium     

On the first integral of the non-linear shallow-membrane equation via Noether's theorem

In this paper, using the invariance identities of Rund [2], involving the Lagrangian and the generators of the infinitesimal Lie group and then using Noether's theorem, the first integral of the shallow-membrane equation has been obtained. Further, through the repeated application of invariance under the transformation obtained its exact solution, for certain particular values of the parameters involved, is obtained by reducing the first integral to quadrature.     

The cost/accuracy approach: a method for selecting filming rate for manual materials handling activities

This paper presents a method for determining filming rate for developing kinetic biomechanical models of manual materials handling activities. Using a high-speed camera, manual lifting activities were filmed at 500 frames per second. Different framing rates were then simulated by skipping one or more film frames. The data analysis indicated that selection of filming rate on the basis of cost and accuracy trade-off is superior to existing framing rate selection criteria. The proposed method can be used for other similar activities.     

Subjective estimates of one-handed carrying tasks

In this study, ten male and five female subjects, ranging between 21 and 23 years in age and in excellent physical health, voluntarily participated. Four different shapes of containers, 8·5 and 12·3 litres in capacity, were used to carry loads for distances of 100, 200, and 300 ft (30·48, 60·96, and 91·44 m, respectively). Individuals first subjectively estimated how much weight they could carry in a given type of container for the required distance and then verified it by actual carrying. The preferred (stronger) hand was used to hold the containers. In addition to the weight acceptable for comfortable carrying, pulse rate and ratings of perceived exertion (RPE) of the arm and whole body were also used as response measures. Results indicated that subjects could quite accurately estimate the amount of weight they could carry comfortably in one hand. RPE for one-handed carrying tasks was not one-tenth of the pulse rate as is the case for whole body tasks. The average pulse rate was 100 beats/min for the weights selected. Shape of the containers significantly influenced the amount of weight subjects were willing to carry in one hand. The acceptable amount of weight decreased with distance, but was found to increase with volume.