141 research outputs found
Development of the mathematical model of catalytic cracking: identification of hydrocarbon of the vacuum distillate usin chromatomass- spectrometry
Information about composition of catalytic cracking raw materials and products is required fordevelopment of mathematical model of catalytic cracking. The results of laboratory investigation ondetermination of the composition of catalytic cracking vacuum distillate were performed in this work. Groupcomposition of the catalytic cracking raw materials was defined using liquid-adsorption chromatographicseparation on silica gel. Paraffin-naphthenic and aromatic fraction was indefined by chromato-massspectrometry
Scaling Propensity of Water
The commonly used Saturation Index calculated at 10°C (SI10) is not suitable for practical situations. New parameters have been developed for simple and rapid analysis of calcium carbonate precipitation (scaling) phenomena which occur during the heating of drinking water: TPCC90 (Theoretically Precipitable Calcium Carbonate at 90°C) SI90 (Saturation Index at 90°C) NI (Nucleation Index) PPCC (Practically Precipitable Calcium Carbonate) Both TPCC90 and SI90 describe the hydrodynamic driven force for the scaling reaction. The nucleation index indicates at what rate calcium carbonate precipitation is accelerated by nuclei present in the water. Finally, the PPCC is a measurement under practical conditions, determining the rate of scaling. The suitability of these parameters for predicting scaling was assessed and detailed results are presented in this publication
Monopoles and Knots in Skyrme Theory
We show that the Skyrme theory actually is a theory of monopoles which allows
a new type of solitons, the topological knots made of monopole-anti-monopole
pair,which is different from the well-known skyrmions. Furthermore, we derive a
generalized Skyrme action from the Yang-Mills action of QCD, which we propose
to be an effective action of QCD in the infra-red limit. We discuss the
physical implications of our results.Comment: 4 pages. Phys. Rev. Lett. in pres
Performance of arthroscopic irrigation systems assessed with automatic blood detection
Biomechanical EngineeringMechanical, Maritime and Materials Engineerin
The double [3+2] photocycloaddition reaction
One of a synthetic organic chemists‟ greatest challenges is to create step-efficient routes toward compounds with high molecular complexity. Therefore, reactions such as the meta
photocycloaddition of an olefin to a benzene derivative, which provide more than one bond in a single step are of significant importance. It this remarkable reaction three new σ bonds, three new rings and up to six new stereocenters are formed simultaneously. Additional complexity can be added by tethering the two reacting partners together and this form of the reaction has found many uses in natural product synthesis.
In this work a remarkable double [3+2] photocycloaddition reaction is reported that results in the formation of a complex cis, cis, cis, trans-[5, 5, 5, 5] fenestrane derivative from a simple flat aromatic acetal with two branching alkenes. During this dramatic transformation four carboncarbon bonds, five new rings and seven new stereocenters are created in a single one-pot process using only UV light. The reaction occurs in a sequential manner from the linear meta photocycloadduct, via a secondary [3+2] addition of the alkene across the cyclopropane of the adduct. In addition, an angular meta photocycloadduct also produced in the initial addition step, undergoes an alternative fragmentation-translocation photoreaction to afford a silphinene-like angular tricyclic compound.
In this work the investigation of this newly discovered process is discussed via the synthesis and subsequent irradiation of a series of photosubstrates containing different functional groups in the arene-alkene tether. In addition, attempts toward the synthesis of alternative structures using the same double [3+2] photocycloaddition are reported
Protease-activated receptor-1 activation by granzyme B causes neurotoxicity that is augmented by interleukin-1 beta
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.This study was funded by the intramural program of the National Institute of Neurological Disorders and Stroke
Corruption in Privatization and Governance Regimes
(ISSN 1827-3580
OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine
This paper summarizes the findings from Phase II of the Offshore Code Comparison,
Collaboration, Continued, with Correlation project. The project is run under the
International Energy Agency Wind Research Task 30, and is focused on validating the
tools used for modeling offshore wind systems through the comparison of simulated
responses of select system designs to physical test data. Validation activities such as
these lead to improvement of offshore wind modeling tools, which will enable the
development of more innovative and cost-effective offshore wind designs. For Phase II
of the project, numerical models of the DeepCwind floating semisubmersible wind
system were validated using measurement data from a 1/50th-scale validation campaign
performed at the Maritime Research Institute Netherlands offshore wave basin.
Validation of the models was performed by comparing the calculated ultimate and
fatigue loads for eight different wave-only and combined wind/wave test cases against
the measured data, after calibration was performed using free-decay, wind-only, and
wave-only tests. The results show a decent estimation of both the ultimate and fatigue
loads for the simulated results, but with a fairly consistent underestimation in the tower
and upwind mooring line loads that can be attributed to an underestimation of waveexcitation
forces outside the linear wave-excitation region, and the presence of
broadband frequency excitation in the experimental measurements from wind.
Participant results showed varied agreement with the experimental measurements
based on the modeling approach used. Modeling attributes that enabled better
agreement included: the use of a dynamic mooring model; wave stretching, or some
other hydrodynamic modeling approach that excites frequencies outside the linear wave
region; nonlinear wave kinematics models; and unsteady aerodynamics models. Also, it
was observed that a Morison-only hydrodynamic modeling approach could create
excessive pitch excitation and resulting tower loads in some frequency bands.This work was supported by the U.S. Department of Energy under Contract No. DEAC36-
08GO28308 with the National Renewable Energy Laboratory. Some of the
funding for the work was provided by the DOE Office of Energy Efficiency and
Renewable Energy, Wind and Water Power Technologies Office
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