BOOK REVIEW: Stuart Smyth, Peter W.B. Phillips, William A. Kerr, and George G. Khachatourians. Regulating the Liabilities of Agricultural Biotechnology.

Agribusiness,

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

The Well-Being of Alcohol and Other Drug Counsellors in Australia: Strengths, Risks, and Implications

Working with alcohol and other drug (AOD) using populations in treatment services is a demanding job that has been associated with a susceptibility to stress and burnout in the workforce. The current study used an online survey methodology in Victoria, Australia, to examine staff well-being and burnout in a cohort of 228 workers in AOD specialist services in Victoria, 151 of whom hold client caseloads. Although there was a strong negative association between stress and burnout, and inverse associations with work satisfaction and well-being, the focus of the current analysis was what predicted positive well-being in workers. This was associated with four factors—lower levels of emotional exhaustion and cognitive weariness (both aspects of burnout), higher levels of opportunities for professional growth, and a greater support network in the worker’s own life with which to discuss things. Thus, positive well-being is not only linked to lower burnout, and to greater perceived development opportunities, but also to the support systems workers have access to

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-

The Brightening of Re50N: Accretion Event or Dust Clearing?

The luminous Class I protostar HBC 494, embedded in the Orion A cloud, is associated with a pair of reflection nebulae, Re50 and Re50N, which appeared sometime between 1955 and 1979. We have found that a dramatic brightening of Re50N has taken place sometime between 2006 and 2014. This could result if the embedded source is undergoing a FUor eruption. However, the near-infrared spectrum shows a featureless very red continuum, in contrast to the strong CO bandhead absorption displayed by FUors. Such heavy veiling, and the high luminosity of the protostar, is indicative of strong accretion but seemingly not in the manner of typical FUors. We favor the alternative explanation that the major brightening of Re50N and the simultaneous fading of Re50 is caused by curtains of obscuring material that cast patterns of illumination and shadows across the surface of the molecular cloud. This is likely occurring as an outflow cavity surrounding the embedded protostar breaks through to the surface of the molecular cloud. Several Herbig-Haro objects are found in the region.Comment: 8 pages, accepted by Ap

A Volume-Limited Sample of Ultracool Dwarfs. I. Construction, Space Density, and a Gap in the L/T Transition

We present a new volume-limited sample of L0-T8 dwarfs out to 25 pc defined entirely by parallaxes, using our recent measurements from UKIRT/WFCAM along with Gaia DR2 and literature parallaxes. With 369 members, our sample is the largest parallax-defined volume-limited sample of L and T dwarfs to date, yielding the most precise space densities for such objects. We find the local L0-T8 dwarf population includes $5.5\%\pm1.3\%$ young objects ($\lesssim$200 Myr) and $2.6\%\pm1.6\%$ subdwarfs, as expected from recent studies favoring representative ages $\lesssim$4 Gyr for the ultracool field population. This is also the first volume-limited sample to comprehensively map the transition from L to T dwarfs (spectral types $\approx$L8-T4). After removing binaries, we identify a previously unrecognized, statistically significant (>4.4$\sigma$) gap $\approx$0.5 mag wide in $(J-K)_{\rm MKO}$ colors in the L/T transition, i.e., a lack of such objects in our volume-limited sample, implying a rapid phase of atmospheric evolution. In contrast, the most successful models of the L/T transition to date $-$ the "hybrid" models of Saumon & Marley (2008) $-$ predict a pile-up of objects at the same colors where we find a deficit, demonstrating the challenge of modeling the atmospheres of cooling brown dwarfs. Our sample illustrates the insights to come from even larger parallax-selected samples from the upcoming Legacy Survey of Space and Time (LSST) by the Vera Rubin Obsevatory.Comment: AJ, in press. 71 pages, 17 figures, 4 tables. Data for all members of the volume-limited sample can be found in the UltracoolSheet at http://bit.ly/UltracoolSheet , a compilation of 3000+ ultracool dwarfs and imaged exoplanets, including photometry, J2000 positions, parallaxes, proper motions, multiplicity, and spectroscopic classifications from multiple surveys and numerous source