A model for the submarine depthkeeping team

The most difficult task the depthkeeping team must face occurs during periscope-depth operations during which they may be required to maintain a submarine several hundred feet long within a foot of ordered depth and within one-half degree of ordered pitch. The difficulty is compounded by the facts that wave generated forces are extremely high, depth and pitch signals are very noisy and submarine speed is such that overall dynamics are slow. A mathematical simulation of the depthkeeping team based on the optimal control models is described. A solution of the optimal team control problem with an output control restriction (limited display to each controller) is presented

Recovery of uranium from seawater.

A computer program entitled URPE (Uranium Recovery Performance and Economics) has been developed to simulate the engineering performance and provide an economic analysis O of a plant recovering uranium from seawater. The conceptual system design used as the focal point for the more general AM analysis consists ofa floating oil-rig type platform, Asinlge-point moored in an open ocean current, using either high volume, low head, propeller pumps or the velocity head 4M of the ambient ocean current to force seawater through a mass transfer medium (hydrous titanium oxide (HTO) coated onto particle beds or stacked tubes), as in most process designs previously suggested for this service. Uranium is recovered Sfrom the seawater by an adsorption process, and later eluted . from the adsorber by an ammonium carbonate solution. A multi-product co-generating plant on board the platform burns coal to raise steam for electricity generation, desalination, and process heat requirements. Scrubbed stack gas from the plant is processed to recover carbon dioxide for chemical make-up needs.The equilibrium isotherm and the diffusion constant for the uranyl-HTO system, which are needed for bed performance calculations, have been calculated based on the rather sparse data reported in the literature. In addition, a technique for calculating the rate constant of a fixed bed adsorbing system has been developed for use with Thomas' solution for predicting fixed bed performance.The URPE program has been benchmarked against the results of previous studies by ORNL and Exxon, and found to make comparable performance and economic estimates when applied under the same set of ground rules. The URPE code was then used in an extensive series of parametric and sensitivity studies to identify optimum bed operating conditions and important areas for future research and development. The program showed that thin beds of small, thinly-coated particles were the preferred bed configuration, and that actively pumped systems out-perform current driven units.Based on the URPE analysis, the minimum expected costs nof uranium recovered from seawater would be no lower than ~316 (1979$)/lb U308 for state-of-the-art adsorber material (capacity equal to 210 mg U/kg Ti), but might be reduced to the level of breakeven attractiveness of ~150 (1979$)/lb U30 8 if at least a four-fold increase in adsorption capacity could be achieved. Specific research and development objectives other than increasing particle capacity are also indentified. Prospects are considered to be sufficiently good to warrant recommending further work

Systems studies on the extraction of uranium from seawater

This report summarizes the work done at MIT during FY 1981 on the overall system design of a uranium-from-seawater facility. It consists of a sequence of seven major chapters, each of which was originally prepared as a stand-alone internal progress report. These chapters trace the historical progression of the MIT effort, from an early concern with scoping calculations to define the practical boundaries of a design envelope, as constrained by elementary economic and energy balance considerations, through a parallel evaluation of actively-pumped and passive current-driven concepts, and thence to quantification of the features of a second generation system based on a shipboard-mounted, actively-pumped concept designed around the use of thin beds of powdered ion exchange resin supported by cloth fiber cylinders (similar to the baghouse flyash filters used on power station offgas).An assessment of the apparently inherent limitations of even thin settled-bed sorber media then led to selection of an expanded bed (in the form of an ion exchange "wool"), which would permit an order of magnitude increase in flow loading, as a desirable advance. Thus the final two chapters evaluate ways in which this approach could be implemented, and the resulting performance levels which could be attained. Overall, U 308 production costs under 200 $/lb appear to be within reach if a high capacity (several thousand ppm U) ion exchange wool can be developed

Energy transfer in nonlinear network models of proteins

We investigate how nonlinearity and topological disorder affect the energy relaxation of local kicks in coarse-grained network models of proteins. We find that nonlinearity promotes long-range, coherent transfer of substantial energy to specific, functional sites, while depressing transfer to generic locations. Remarkably, transfer can be mediated by the self-localization of discrete breathers at distant locations from the kick, acting as efficient energy-accumulating centers.Comment: 4 pages, 3 figure

Direct cross section measurement for the 18O(p,γ)19F reaction at astrophysical energies at LUNA

18 O ( p, γ ) 19 F plays an important role in the AGB star scenarios. The low energy cross section could be influenced by a hypothetical low energy resonance at 95 keV and by the tails of the higher energy broad states. The 95 keV resonance lies in the energy window corresponding to the relevant stellar temperature range of 40-50 MK.Measurements of the direct cross section were performed at the Laboratory for Underground Nuclear Astrophysics (LUNA), including the unobserved low energy resonance, the higher energy resonances and the non-resonant component, taking advantage of the extremely low environmental background. Here we report on the experimental setup and the status of the analysis

Multi-robot region-of-interest reconstruction with Dec-MCTS

© 2019 IEEE. We consider the problem of reconstructing regions of interest of a scene using multiple robot arms and RGB-D sensors. This problem is motivated by a variety of applications, such as precision agriculture and infrastructure inspection. A viewpoint evaluation function is presented that exploits predicted observations and the geometry of the scene. A recently proposed non-myopic planning algorithm, Decentralised Monte Carlo tree search, is used to coordinate the actions of the robot arms. Motion planning is performed over a navigation graph that considers the high-dimensional configuration space of the robot arms. Extensive simulated experiments are carried out using real sensor data and then validated on hardware with two robot arms. Our proposed targeted information gain planner is compared to state-of-the-art baselines and outperforms them in every measured metric. The robots quickly observe and accurately detect fruit in a trellis structure, demonstrating the viability of the approach for real-world applications

Delayed neutron assay to test sorbers for uranium-from-seawater applications

Delayed Fission Neutron (DFN) assay has been applied to the measurement of uranium content in sorbers exposed to natural seawater for the purpose of evaluating advanced ion exchange resins. DFN assay was found to be particularly suitable for such testing because it is selective, nondestructive, yields quantitative results in the submicrogram range, and requires relatively simple sample preparation. Surplus components for a DFN system were obtained from the Lawrence Livermore National Laboratory, modified, re-assembled, and calibrated for use with M.I.T. irradiation facilities, following which procedures were developed, evaluated and applied to the experiments at hand.Four experimental ion exchange resins developed by the Rohm and Haas (R&H) Company specifically for uraniumfrom- seawater applications were evaluated, together with hydrous titanium oxide (HTO), the leading inorganic sorber for this purpose. Two types of tests using natural seawater were employed: batch loading experiments (paralleling similar tests done by R&H), and fixed-bed column loading experiments using a test facility at the Woods Hole Oceanographic Institute (WHOI). While some qualitatively consistent trends were evident among the various experiments, important quantitative inconsistencies were noted. The WHOI tests most closely approximated true in-service conditions; hence, more importance is assigned to these results.The MIT/WHOI tests confirmed 1.5 mm HTO particle bed uptake of approximately 300 ppm U for a 30 day exposure, in good agreement with the results reported by other laboratories, worldwide. An anion exchange resin employing an amidoxime functional group also achieved this level of performance, and, in addition, exhibited considerably superior mechanical properties. Moreover, the resin performance is expected to improve when its properties are optimized for the present application.U.S. Dept. of Energy

Delayed neutron assay to test sorbers for uranium-from-seawater applications

Includes bibliographical references (pages 106-107)Final Report of the Uranium from Seawater Project ; FY 1981U.S. Dept. of Energy 80-499-

Remote sensing applications to resource problems in South Dakota

There are no author-identified significant results in this report