Contact dynamic modeling of a liquid droplet between two approaching porous materials

A computational fluid dynamics model based on a finite difference solution to mass and momentum conservation equations (Navier–Stokes equations) for a liquid droplet transport between two porous or nonporous contacting surfaces (CSs) is developed. The CS dynamic (equation of motion) and the spread of the incompressible liquid available on the primary surface for transfer are coupled with the Navier–Stokes equations. The topologies of the spread dynamic between and inside both surfaces (primary and CSs) are compared with experimental data. The amount of mass being transferred into the CS, predicted by the model, is also compared to the experimental measurements. The impact of the initial velocity on the spread topology and mass transfer into the pores is addressed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2346–2353, 2014     

Decaking of bituminous coals by alkaline solutions

Experimental results are reported concerning the decaking effect of alkalies on two Western Kentucky coals. Decaking treatment with dilute sodium hydroxide solutions was the most effective of the various methods examined. Caking and agglomerating character were destroyed when about 1–2 wt % (dry basis) sodium hydroxide was retained by the coal following the solution treatment. The free-swelling index was considerably reduced for both seam coals. In contrast, 20 wt % of sodium hydroxide was required in a dry mixing method. The amount of decaking reagent required for effective solution treatment varied with seam of origin but the difference in particle size range and/or mineral content may have been significant. Independent effects of these variables were not determined. Experimental results indicate that the decaking reactions occur at temperatures above 300 °C, but the actual mechanisms are not known. The alkaline-solution decaking treatment was conceived as a possible step in coal preparation for a coal-gasification process. Various important questions remain for continued study.     

Non-proliferation attributes of molten salt reactors

Molten salt reactors (MSR) have many non-proliferation attributes. They can operate on the thorium-uranium fuel cycle which protects the fissile material by the daughter products of the inseparable U-232. MSRs can completely fission all plutonium and HEU, and as desired, ‘convert’ them to U-233. This also results in high, and efficient resource utilization, while diminishing the plutonium stock. On line processing, when applied, could free the waste from all fissile material. The fuel in the reactor stays protected by the intense radiation of the fission products. Fuel can also be protected in the reactor as well as outside the reactor by denaturing with natural uranium. A wide variety of MSRs are available, from ‘once through’ minimum processing reactors to ones with fuel processing which can breed fuel for converters. MSRs are extremely safe and simple reactors with good economic potential.     

An Autonomous Spacecraft Agent Prototype

This paper describes the New Millennium Remote Agent (NMRA) architecture for autonomous spacecraft control systems. The architecture supports challenging requirements of the autonomous spacecraft domain not usually addressed in mobile robot architectures, including highly reliable autonomous operations over extended time periods in the presence of tight resource constraints, hard deadlines, limited observability, and concurrent activity. A hybrid architecture, NMRA integrates traditional real-time monitoring and control with heterogeneous components for constraint-based planning and scheduling, robust multi-threaded execution, and model-based diagnosis and reconfiguration. Novel features of this integrated architecture include support for robust closed-loop generation and execution of concurrent temporal plans and a hybrid procedural/deductive executive.We implemented a prototype autonomous spacecraft agent within the architecture and successfully demonstrated the prototype in the context of a challenging autonomous mission scenario on a simulated spacecraft. As a result of this success, the integrated architecture has been selected to fly as an autonomy experiment on Deep Space One (DS-1), the first flight of NASA';s New Millennium Program (NMP), which will launch in 1998. It will be the first AI system to autonomously control an actual spacecraft.     

Heat transfer enhancement via liquid–liquid phase separation

The heat transfer and flow phenomena during phase separation of partially miscible liquid solvent system were investigated experimentally. The experiments were conducted with a three components system which has an upper critical solution temperature, using critical and off-critical compositions of the solvent mixtures. The convective heat transfer rates were studied for laminar flow in a small diameter horizontal tube and for free convection from its outer surface. It was found that with phase separation the forced convective heat transfer can be augmented by up to 130% compared to heat transfer rates obtained in single phase flow (without phase separation). However, for low quenching rate and depth associated mainly with experiments conducted with critical compositions, deterioration of the heat transfer rates was observed. The free convection heat transfer coefficients were found to be augmented up to 100%. Macro- and micro-flow visualization were also conducted to follow the flow phenomena during the phase separation, and the mechanisms responsible to the heat transfer enhancement are discussed.     

Interaction between Asp-85 and the proton-releasing group in bacteriorhodopsin. A study of an O-like photocycle intermediate

Upon light adaptation by continuous (or pulsed) illumination, the artificial bacteriorhodopsin (bR) pigments, I and II, derived from synthetic 14F retinal and a short polyenal, respectively produce a long-lived red-shifted species denoted O1. An analogous phenomenon was observed by Sonar, S., et al. [(1993) Biochemistry 32, 2263-2271], in the case of the Y185F mutant (pigment III). The nature of these O1 species was investigated by studying a series of effects, primarily their red light photoreversibility, the associated proton uptake and release processes, and the effects of pH on their relative amounts, which are interpreted in terms of pH-dependent acid-base equilibria. Experiments were also carried out with pigments I and II derived from the mutants D96A, E204Q, R82Q, and D85N. The O1 species of pigments I and II (and possibly also that of pigment III) are identified as an unusually long-lived (all-trans) intermediate of the photocycle of their 13-cis isomer. It is concluded that in O1, Asp-85 is protonated, a process associated with proton uptake from the extracellular side. Subsequent proton release (to the same side of the membrane) occurs from Glu-204 (or from a group closely interacting with it) prior to the decay of O1. At high pH (>9), O1 reversibly converts to a purple form, due to deprotonation of Asp-85, while at still higher pH (> 11), a blue-shifted species characterized by a deprotonated Schiff base is generated. These transitions constitute the first demonstration of the titration of a photocycle intermediate of a retinal protein. The respective pKa values are determined and discussed in relation to those pertaining to the unphotolyzed (dark-adapted) pigments. It appears that the pKa values are controlled by a hydrogen bond network involving water molecules, which binds the protonated Schiff base with Asp-85 and Glu-204. The disruption of this network in pigments I-III may also be responsible for the long lifetime of the O1 species, due to the inhibition of thermal trans-13-cis isomerization. The results are relevant to the molecular mechanism of the photocycles of both 13-cis- and all-trans-bR, primarily to the nature and to the deprotonation mechanism of the proton-releasing group.     

Olfactory receptor proteins. Expression, characterization and partial purification

A rat olfactory epithelium cDNA library was screened for olfactory receptor clones. One of the positively hybridizing cDNA clones was sequenced and found to encode a new member of the olfactory receptor superfamily. This cDNA, termed olp4, was used as a model of olfactory receptor for expression, both in vitro and in vivo. Expression of olp4, as well as of another previously cloned olfactory receptor (F5), was monitored by immunoprecipitation was a monoclonal antibody directed against a Flag peptide epitope tag, inserted at the N-terminus of the open reading frame, and a specific polyclonal antibody against a C-terminal peptide of olp4. Translation in vitro, followed by immunoprecipitation, showed a major olp4-specific band of 27-29 kDa. The olp4 and F5 polypeptides were found to be inserted into microsomal membranes as expected for integral membrane proteins. Expression in vivo of Flag-olp4 in Sf9 insect cells, using the baculovirus expression system, showed a specific polypeptide of the same size as the in vitro species, with an additional band of 34 kDa, which is most likely a glycosylated form. Fluorescence cytometry and immunohistochemical assays demonstrated the localization of the Flag-olp4 product on the cell surface of the infected host Sf9 cells, with the N-terminus and C-terminus in the proper orientation. Affinity chromatography was used for the partial purification of the olp4 polypeptide from infected Sf9 cells. The identification and purification of this expressed olfactory receptor polypeptide could open the way for further characterization and functional studies of the olfactory receptor superfamily members.     

Memoryless execution: A programmer's viewpoint

A set of rules for memoryless execution on third-gene ration computer systems is presented. These rules facilitate binary memoryless interactions within the context of a trustable operating system, without restricting the dynamic use of central processor general purpose registers. An estimate of the required machine support indicates that the firmware modifications required for an implementation based on a segmented microprogrammable computer are not extensive. It is shown that the impact of the solution on operating system design is modest. Moreover, programming generality among memoryless programs is maintained.     

Specific impact of radio and television on children's story comprehension.

A cross-media comparison of TV and radio elucidated the specific strengths of each medium for transmitting explicit and implicit story content. 48 elementary school children in 2 age groups (6.5–8 yrs and 9–10.5 yrs) were exposed to an animated audiovisual (TV) and an audio (radio) story. A narration of the original story text served as the common soundtrack. The design was counterbalanced for story-medium combinations and orders. Except for the inclusion of characters, recall of the explicit story content was equivalent across media. However, recall of details from the story was improved with a TV presentation. Recognition of expressive language was facilitated by a radio story, whereas picture sequencing was augmented by a TV story. The radio story also elevated the use of knowledge unrelated to the story for inferences by younger Ss and verbal sources for both ages, whereas the TV story enhanced inferences based on actions. Findings emphasize the need to consider the differential impact of media for conveying explicit and implicit content. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)