1,476 research outputs found
PREVIEW—Murray v. BEJ Minerals, LLC: Finding a Home for Fossils
The Montana Supreme Court will hear oral arguments in this matter on Thursday, November 7, 2019 at 9:30 AM in the courtroom of the Montana Supreme Court, Joseph P. Mazurek Building, Helena, Montana. The Honorable Olivia Rieger will hear the case in place of Justice Jim Rice, who recused himself. Eric B. Wolff is expected to argue for the Appellants. Harlan B. Krogh is expected to argue for the Appellees
Children\u27s Books
Shusterman, Neil. (1994). The Eyes of Kid Midas; Hughes, Shirley. (1994). The Nursery Collection; Barnes-Murphy, Frances. (1994). The Fables of Aesop; Lerner, Carol. (1994). Backyard Birds of Winter; Hamanaka, Sheila. (1994). All the Colors of the Earth; Juster, Norton. (1994). Otter Nonsense
Sturgeon v. Frost
After two trips to the United States Supreme Court, an Alaskan moose hunter secured motorized access to his hunting ground while establishing Alaska as the exception, rather than the rule, regarding federal land management. In a much-anticipated holding, the Court determined that the surface waters of the Nation River within the Yukon-Charley Rivers National Preserve qualify as “private” land and therefore fall beyond the control of the National Park Service. The decision stripped the Park Service of normal regulatory authority over navigable waters within Alaska’s national parks, prompting a concurrence urging Congress to clarify resulting ambiguities
A practical method for simultaneously determining the effective burst sizes and cycle times of viruses
Parallel Deterministic and Stochastic Global Minimization of Functions with Very Many Minima
The optimization of three problems with high dimensionality and many local minima are investigated
under five different optimization algorithms: DIRECT, simulated annealing, Spall’s SPSA algorithm, the KNITRO
package, and QNSTOP, a new algorithm developed at Indiana University
Dimethylsilanediol (DMSD) Source Assessment and Mitigation on ISS: Estimated Contributions from Personal Hygiene Products Containing Volatile Methyl Siloxanes (VMS)
Dimethylsilanediol (DMSD) is a small organosilicon compound present in humidity condensate on the International Space Station. Aqueous DMSD originates from volatile methyl siloxane (VMS) compounds in the ISS cabin atmosphere. DMSD is not effectively removed by the WPA (Water Processor Assembly), requiring removal and replacement of both WPA Multifiltration (MF) Beds for an estimated resupply penalty of approximately 70 kg/year. Analyses indicate that WPA can handle DMSD if the concentration in the condensate can by reduced by fifty percent. Personal Hygiene Products (PHPs) used by crew are suspected to be a significant source of VMS. Source removal of VMS will be required to achieve a measurable impact to the DMSD concentration in the condensate. The inventory of total crew provisions for ISS was analyzed to identify silicon containing materials and products used for personal hygiene that emit VMS. Accounting for the wide range in mass of hygiene product applied to skin or hair, the frequency of application, the product selection, the number of crew using a given product, the range in silicon mass fraction of different products, and the potential vaporization of the product, the potential total VMS emissions from personal hygiene products for a crew of six on ISS were estimated. The total daily VMS emissions from PHPs estimate ranges from 261 to 1145 mg-Si per day, compared to total estimated VMS generation rates on ISS of 800 to 1500 mg-Si per day. The main sources of VMS were determined to be antiperspirants (173 to 696 mg-Si per day), skin lotions (63 to 248 mg-Si per day), wipes (25 to 124 mg-Si per day) and hair conditioner (0 to 69 mg-Si per day). Several siloxanes-free options are available for deodorants, wet wipes, lotions, and leave-in conditioners. These products are now being assessed for crew member use in future increments
INFLUENCE OF EXTERNAL FORCES ON THE CONTROL AND PERFORMANCE OF A MINIMUM TIME SHOULDER FLEXION TASK
INTRODUCTION AND METHODS We have been using planar mathematical models to simulate the task of a rapid bilateral arm raise and to obtain minimum movement time solutions. Here we report the effect of gravity (G), ground reaction force (GRF) and center of pressure (COP) location on the solutions of a three segment model. We modeled the arms as a rigid segment, the head, torso, upper and lower legs as a second rigid segment, and the feet as a third rigid segment. The shoulder and ankle joints were modeled as revolute pin joints. A nonlinear rotational spring and damper restrained the movement of the ankle joint within physiological limits. Joint muscle torques were generated through two idealistic torque generators. Torque history values (for each joint) were controlled by eight evenly spaced nodes, while intermediate values were obtained by linear interpolation. The foot to ground interaction was modeled with the use of two 2-D springs (nonlinear vertically, linear horizontally) and dampers. One set was attached at the toes and one at the heel. Thus, the feet were free to move off and slide along the ground depending on the dynamics of the simulation. The initial position was quiet erect stance with the arms and feet perpendicular to it. A variable step integrator was used for the forward simulations. The parameterized torque histories were optimized using a nonlinear optimization algorithm. We compared solutions with G, without G (free floating or attached to the ground), and with the COP location at the initial and final state proscribed to be either below the ankle joint or at the middle of the feet. This adjustment of the COP was accomplished by defining the initial and final orientation of the body segment. The arms and feet initial and final orientation, as well as the anthropometric parameters and strength limits of the model were held constant for all solutions. RESULTS AND CONCLUSIONS The overall performance and &ody kinematics were very similar and well within human subject experimental results, but the 1G condition revealed higher maximum arm angular velocity (8radsec) than the OG conditions (7 radsec). Although the 1G solution used maximum ankle torque, the heel moved up minimally (< 6 mm) only early in the stopping phase. On the other hand, although the OG free floating solution used minimal ankle torque values, there was maximum dorsiflexion followed by maximum plantarflexion. The 1G condition revealed significant plantar- and shoulder-flexion torques at the end of the movement that the OG attached to the floor model did not have. Finally, the two COP conditions produced opposite ankle torque coordination, a variability also observed during human subject experiments
Elastic Forces Drive Nonequilibrium Pattern Formation in a Model of Nanocrystal Cation Exchange
Cation exchange is a useful tool for post-synthetic modification of
nanocrystals, yet its mechanisms remain poorly understood. Here, we explore an
idealized model for ion exchange in which a chemical potential drives
compositional defects to accumulate at a crystal's surface. These impurities
subsequently diffuse inward. We find that the nature of interactions between
sites in a compositionally impure crystal strongly impacts exchange
trajectories. In particular, elastic deformations which accompany
lattice-mismatched species promote spatially modulated patterns in the
composition. These same patterns can be produced at equilibrium in core/shell
nanocrystals, whose structure mimics transient motifs observed in
nonequilibrium trajectories. Moreover, the core of such nanocrystals undergoes
a phase transition - from modulated to unstructured - as the thickness or
stiffness of the shell is decreased. Our results help explain the varied
patterns observed in heterostructured nanocrystals produced by cation exchange
and suggest principles for the rational design of compositionally-patterned
nanomaterials
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