Experimental constraints on fluid-rock reactions during incipient serpentinization of harzburgite
Klein, Frieder
2014-10-20
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9 records were found.
This thesis describes the advancements of the application of thermal tensioning techniques to different weld geometries in order to eliminate buckling distortion. The main goal of this work is to better understand these techniques through experimental and numerical investigation and increase their technological maturity to aid industrial implementation. The thermal tensioning techniques investigated in this work are Thermal Tensioning by Cooling and Thermal Tensioning by Heating. The investigation for both techniques encompasses thermal source characterisation, application to different weld geometries and residual stress measurements and analysis of both butt and fillet welded samples.
A detailed technology transfer study of Thermal Tensioning by Cooling was carried out in which different aspects of the application of TTC to arc weldin...
This work investigates the use of shape memory alloys (SMAs) for vibration isolation
and damping of mechanical systems. The first part of this work evaluates the nonlinear
dynamics of a passive vibration isolation and damping (PVID) device through
numerical simulations and experimental correlations. The device, a mass connected
to a frame through two SMA wires, is subjected to a series of continuous acceleration
functions in the form of a sine sweep. Frequency responses and transmissibility of the
device as well as temperature variations of the SMA wires are analyzed for the case
where the SMA wires are pre-strained at 4.0% of their original length. Numerical
simulations of a one-degree of freedom (1-DOF) SMA oscillator are also conducted
to corroborate the experimental results. The configuration of the SMA oscillator is
based on the P...
Oxidative stress, primarily due to increased
generation of reactive oxygen species (ROS) and
reactive nitrogen species (RNS), is a feature of many
viral infections. ROS and RNS modulate the
permissiveness of cells to viral replication, regulate host
inflammatory and immune responses, and cause
oxidative damage to both host tissue and progeny virus.
The lipid-rich nervous system is particularly susceptible
to lipid peroxidation, an autocatalytic process that
damages lipid-containing structures and yields reactive
by-products, which can covalently modify and damage
cellular macromolecules. Oxidative injury is a
component of acute encephalitis caused by herpes
simplex virus type 1 and reovirus, neurodegenerative
disease caused by human immunodeficiency virus and
murine leukemia virus, and subacute sclerosing
panencephaliti...
Local mechanical tensioning is one of the most efficient and industrially relevant stress engineering techniques to modify weld residual stress field and subsequently reduce buckling distortion. However, application of rolling load and its magnitude need to be optimised for an energy efficient rolling process. In the present study gas metal arc butt welded plates of low carbon mild steel were rolled by a dual roller in different rolling configuration (top and reverse side rolling) and with different magnitude of rolling load. All the plates were rolled post welding. Residual strain profiles of the post weld rolled plates were measured, using the SALSA strain scanner, and the inplane stress were characterized. Average distortion of the rolled plates was correlated with the residual stress state. Reverse rolling was found to be more effe...
Residual stress and distortion continue to be important issues in shipbuilding
and are still subject to large amounts of research. This paper demonstrates how
the type of welding process influences the amount of distortion. Many shipyards
currently use submerged arc welding (SAW) as their welding process of choice. In
this manuscript we compare welds made by SAW with DC gas metal arc welding,
pulsed gas metal arc welding, Fronius Cold Metal Transfer (CMT), autogenous
laser and laser hybrid welding on butt welds in 4mm thick DH36 ship plate. Laser
and laser hybrid welding were found to produce the lowest distortion.
Nevertheless a considerable improvement can be achieved with the pulsed gas
metal arc welding and CMT processes. The paper seeks to understand the
relationship between heat input, fusion area, measured distortion and the
res...
This study presents a new ion–neutral chemical model coupled into the Whole Atmosphere Community Climate Model (WACCM). The ionospheric D-region (altitudes ∼ 50–90 km) chemistry is based on the Sodankylä Ion Chemistry (SIC) model, a one-dimensional model containing 307 ion–neutral and ion recombination, 16 photodissociation and 7 photoionization reactions of neutral species, positive and negative ions, and electrons. The SIC mechanism was reduced using the simulation error minimization connectivity method (SEM-CM) to produce a reaction scheme of 181 ion–molecule reactions of 181 ion–molecule reactions of 27 positive and 18 negative ions. This scheme describes the concentration profiles at altitudes between 20 km and 120 km of a set of major neutral species (HNO3, O3, H2O2, NO, NO2, HO2, OH, N2O5) and ions (O2+, O4+, NO+, NO+(H2O), O2+...
Vanderbilt Digestive Disease Center (Grant P30DK058404)
