Engineering topics

Jenkins, James

Publications and source records attributed to Jenkins, James.

6 records

DOE OSTI2017

Conversion of lanthanide glutarate chlorides with interstitial THF into lanthanide glutarates with unprecedented topologies

Here, using slow diffusion methods at room temperature (RT), we obtained four isomorphous lanthanide glutarate chlorides, accommodating interstitial THF and water molecules, [Ln 2 (Glut) 2 Cl 2 (H 2 O) 8 ]·2H 2 O·THF, with Ln = La , Ce, Pr, Nd. They assemble as 3-dimensional (3D) lanthanide (Ln) coordination polymers with LnO 10 coordination polyhedra. Their topology was elucidated to be a 4-coordinated sql net. slowly dissolve in water liberating the entrapped THF molecules and reassemble as regular Ln-glutarate hydrates when the solution is deprived of THF and water by slow evaporation. The new products crystallize as [Ln 2 (Glut) 3 (H 2 O) 3 ]·5H 2 O, with Ln = La, Ce, Pr, and [Nd 2 (Glut) 3 (H 2 O) 2 ]·3.5H 2 O.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2017

Magnetically-Driven Convergent Instability Growth platform on Z.

Hydrodynamic instability growth is a fundamentally limiting process in many applications. In High Energy Density Physics (HEDP) systems such as inertial confinement fusion implosions and stellar explosions, hydro instabilities can dominate the evolution of the object and largely determine the final state achievable. Of particular interest is the process by which instabilities cause perturbations at a density or material interface to grow nonlinearly, introducing vorticity and eventually causing the two species to mix across the interface. Although quantifying instabilities has been the subject of many investigations in planar geometry, few have been done in converging geometry. During FY17, the team executed six convergent geometry instability experiments. Based on earlier results, the platform was redesigned and improved with respect to load centering at installation making the installation reproducible and development of a new 7.2 keV, Co He-a backlighter system to better penetrate the liner. Together, the improvements yielded significantly improved experimental results. The results in FY17 demonstrate the viability of using experiments on Z to quantify instability growth in cylindrically convergent geometry. Going forward, we will continue the partnership with staff and management at LANL to analyze the past experiments, compare to hydrodynamics growth models, and design future experiments.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS1999

Gas-Particle Interactions in a Microgravity Flow Cell

We are developing a microgravity flow cell in which to study the interaction of a flowing gas with relatively massive particles that collide with each other and with the moving boundaries of the cell. The absence of gravity makes possible the independent control of the relative motion of the boundaries and the flow of the gas. The cell will permit gas-particle interactions to be studied over the entire range of flow conditions over which the mixture is not turbulent. Within this range, we shall characterize the viscous dissipation of the energy of the particle fluctuations, measure the influence of particle-phase viscosity on the pressure drop along the cell, and observe the development of localized inhomogeneities that are likely to be associated with the onset of clusters. These measurements and observations should contribute to an understanding of the essential physics of pneumatic transport.

Louge, Michel↗

NASA NTRS1994

Enhanced/Synthetic Vision Systems for Advanced Flight Decks

One of the most challenging arenas for enhanced and synthetic vision systems is the flight deck. Here, pilots must perform active and supervisory control behaviors based on imagery generated in real time or transduced from imaging sensors. Although enhanced and synthetic vision technologies have been used in military vehicles for more than two decades, they have only recently been considered for civilian transport aircraft. In this paper we discuss the human performance issues still to be resolved for these systems, and consider the special constraints that must be considered for their use in the transport domain.

Kaiser, Mary K.↗

NASA NTRS1990

NASA Information Sciences and Human Factors Program

Fiscal year 1989 descriptions of technical accomplishments in seven sections are presented: automation and robotics; communications; computer sciences; controls and guidance; data systems; human factors; and sensor technology.

Holcomb, Lee↗

NASA NTRS1989

NASA information sciences and human factors program

The FY 1988 descriptions of technical accomplishments is presented in seven sections: Automation and Robotics, Communications Systems, Computer Sciences, Controls and Guidance, Data Systems, Human Factors, and Sensor Technology.

Holcomb, Lee↗