1,322 research outputs found
Coal desulfurization by low temperature chlorinolysis, phase 2
An engineering scale reactor system was constructed and operated for the evaluation of five high sulfur bituminous coals obtained from Kentucky, Ohio, and Illinois. Forty-four test runs were conducted under conditions of 100 by 200 mesh coal,solvents - methlychloroform and water, 60 to 130 C, 0 to 60 psig, 45 to 90 minutes, and gaseous chlorine flow rate of up to 24 SCFH. Sulfur removals demonstrated for the five coals were: maximum total sulfur removal of 46 to 89% (4 of 5 coals with methylchloroform) and 0 to 24% with water. In addition, an integrated continuous flow mini-pilot plant was designed and constructed for a nominal coal rate of 2 kilograms/hour which will be operated as part of the follow-on program. Equipment flow sheets and design drawings are included for both the batch and continuous flow mini-pilot plants
Coal desulfurization by aqueous chlorination
A method of desulfurizing coal is described in which chlorine gas is bubbled through an aqueous slurry of coal at low temperature below 130 degrees C., and at ambient pressure. Chlorinolysis converts both inorganic and organic sulfur components of coal into water soluble compounds which enter the aqueous suspending media. The media is separated after chlorinolysis and the coal dechlorinated at a temperature of from 300 C to 500 C to form a non-caking, low-sulfur coal product
Nuclear spin selective laser control of rotational and torsional dynamics
We explore the possibility of controlling rotational-torsional dynamics of
non-rigid molecules with strong, non-resonant laser pulses and demonstrate
that transient, laser-induced torsional alignment depends on the nuclear spin
of the molecule. Consequently, nuclear spin isomers can be manipulated
selectively by a sequence of time-delayed laser pulses. We show that two
pulses with different polarization directions can induce either overall
rotation or internal torsion, depending on the nuclear spin.Nuclear spin
selective control of the angular momentum distribution may open new ways to
separate and explore nuclear spin isomers of polyatomic molecules
Histaminylation of glutamine residues is a novel posttranslational modification implicated in G-protein signaling
Posttranslational modifications (PTM) have been shown to be essential for protein function and signaling. Here we report the identification of a novel modification, protein transfer of histamine, and provide evidence for its function in G protein signaling. Histamine, known as neurotransmitter and mediator of the inflammatory response, was found incorporated into mastocytoma proteins. Histaminylation was dependent on transglutaminase II. Mass spectrometry confirmed histamine modification of the small and heterotrimeric G proteins Cdc42, Galphao1 and Galphaq. The modification was specific for glutamine residues in the catalytic core, and triggered their constitutive activation. TGM2-mediated histaminylation is thus a novel PTM that functions in G protein signaling. Protein alphamonoaminylations, thus including histaminylation, serotonylation, dopaminylation and norepinephrinylation, hence emerge as a novel class of regulatory PTMs
Set-up of the cryogenic phase equilibria test stand CryoPHAEQTS
The design of processes using cryogenic fluid mixtures requires fluid property data, which is unavailable today. In particular, this data is crucial to develop cryogenic mixed-refrigerant cycles for high-temperature superconductor (HTS) applications and to further optimize hydrogen liquefaction processes. CryoPHAEQTS, which is currently being built at KIT, will provide physical property data for fluid mixtures in a temperature range of 15–300K and at pressures up to 15 MPa, including also mixtures with either flammable or oxidizing components (e.g. hydrogen, deuterium, oxygen). By direct sampling from an equilibrium cell, vapor-liquid equilibria (VLE) and vapor-liquid-liquid equilibria (VLLE) can be determined using gas chromatography. Solid-liquid equilibria (SLE) are measured using a calorimetric method. The measurement of heat capacities is implemented by combining two different flow measurement principles. In addition, the test stand offers optical access for a future upgrade with an optical measurement system that allows in-equilibrium measurements of both bulk transport properties by dynamic light scattering (DLS) and surface tension by surface light scattering (SLS)
Integrated Structure and Semantics for Reo Connectors and Petri Nets
In this paper, we present an integrated structural and behavioral model of
Reo connectors and Petri nets, allowing a direct comparison of the two
concurrency models. For this purpose, we introduce a notion of connectors which
consist of a number of interconnected, user-defined primitives with fixed
behavior. While the structure of connectors resembles hypergraphs, their
semantics is given in terms of so-called port automata. We define both models
in a categorical setting where composition operations can be elegantly defined
and integrated. Specifically, we formalize structural gluings of connectors as
pushouts, and joins of port automata as pullbacks. We then define a semantical
functor from the connector to the port automata category which preserves this
composition. We further show how to encode Reo connectors and Petri nets into
this model and indicate applications to dynamic reconfigurations modeled using
double pushout graph transformation
Qualification of electron-beam welded joints between copper and stainless steel for cryogenic application
Joints between copper and stainless steel are commonly applied in cryogenic systems. A relatively new and increasingly important method to combine these materials is electron-beam (EB) welding. Typically, welds in cryogenic applications need to withstand a temperature range from 300K down to 4 K, and pressures of several MPa. However, few data are available for classifying EB welds between OFHC copper and 316L stainless steel. A broad test program was conducted in order to qualify this kind of weld. The experiments started with the measurement of the hardness in the weld area. To verify the leak-tightness of the joints, integral helium leak tests at operating pressures of 16MPa were carried out at roomand at liquid nitrogen temperature. The tests were followed by destructive tensile tests at room temperature, at liquid nitrogen and at liquid helium temperatures, yielding information on the yield strength and the ultimate tensile strength of the welds at these temperatures. Moreover, nondestructive tensile tests up to the yield strength, i.e. the range in which the weld can be stressed during operation, were performed. Also, the behavior of the weld upon temperature fluctuations between room- and liquid nitrogen temperature was tested. The results of the qualification indicate that EB welded joints between OFHC copper and 316L stainless steel are reliable and present an interesting alternative to other technologies such as vacuum brazing or friction welding
A Next-Generation qPlus-Sensor-Based AFM Setup: Resolving Archaeal S-layer Protein Structures in Air and Liquid
Surface-layer (S-layer) proteins form the outermost envelope in many bacteria
and most archaea and arrange in 2D quasi-crystalline structures via
self-assembly. We investigated S-layer proteins extracted from the archaeon
Pyrobaculum aerophilium with a qPlus sensor-based atomic force microscope (AFM)
in both liquid and ambient conditions and compared it to transmission electron
microscopy (TEM) images under vacuum conditions. For AFM scanning, a
next-generation liquid cell and a new protocol for creating long and sharp
sapphire tips was introduced. Initial AFM images showed only layers of residual
detergent molecules (SDS), which are used to isolate the S-layer proteins from
the cells. SDS was not visible in the TEM images, requiring a more thorough
sample preparation for AFM measurements. These improvements allowed us to
resolve the crystal-like structure of the S-layer samples with
frequency-modulation AFM in both air and liquid
Symbolic Implementation of Connectors in BIP
BIP is a component framework for constructing systems by superposing three
layers of modeling: Behavior, Interaction, and Priority. Behavior is
represented by labeled transition systems communicating through ports.
Interactions are sets of ports. A synchronization between components is
possible through the interactions specified by a set of connectors. When
several interactions are possible, priorities allow to restrict the
non-determinism by choosing an interaction, which is maximal according to some
given strict partial order.
The BIP component framework has been implemented in a language and a
tool-set. The execution of a BIP program is driven by a dedicated engine, which
has access to the set of connectors and priority model of the program. A key
performance issue is the computation of the set of possible interactions of the
BIP program from a given state.
Currently, the choice of the interaction to be executed involves a costly
exploration of enumerative representations for connectors. This leads to a
considerable overhead in execution times. In this paper, we propose a symbolic
implementation of the execution model of BIP, which drastically reduces this
overhead. The symbolic implementation is based on computing boolean
representation for components, connectors, and priorities with an existing BDD
package
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