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Quick attach and release fluid coupling assembly is self-aligning, self-sealing
Fluid coupling assembly that is self-aligning, self-sealing and contains a bellow ball and socket coupling for quick attach and release is highly reliable and can handle cryogenic fluids where icing is encountered. The fluid coupling assembly is used in many fluid systems but is particularly applicable to cryogenic systems
Estimating Drift Parameters in a Fractional Ornstein Uhlenbeck Process with Periodic Mean
We construct a least squares estimator for the drift parameters of a
fractional Ornstein Uhlenbeck process with periodic mean function and long
range dependence. For this estimator we prove consistency and asymptotic
normality. In contrast to the classical fractional Ornstein Uhlenbeck process
without periodic mean function the rate of convergence is slower depending on
the Hurst parameter , namely
Development of pre-clinical and clinical models to predict the efficacy and safety of vaginal microbicides
A suite of mathematical models to simulate the water and salt circulation in the Vaal River water supply system
A thesis submitted to the Faculty of Engineering
University of the Witwatersrand Johannesburg
' for the degree of Doctor of Philosophy
September 1981The Pretoria-Witwatersrand-Vereeniging (PW) complex relies for
water supply on the resources of the Vaal basin# supplemented
by Importation from the Tugela river. Most of the water
supplied to the region is abstracted from the Vaal Barrage#
which is also the sink for much of the water-borne pollution
generated in the southern portion of the PWV complex. This
feature of the system has led to an ever-increasing build-up of
total dissolved solids (TDS) in the water supplies# resulting
in substantial economic loss to consumers. Increasing
mineralization is ascribable mainly to return of effluents to
the Vaal Barrage where the concentrated salts are re-introduced
to the Rand Water Board distribution system. The problem is
exacerbated by the washoff, during the wet season#
of enormous diffuse-source salt loads# leading to intolerably
high peak TDS concentrations.
A suite of deterministic mathematical models has been developed,
and successfully tested, with the aim of predicting the
anticipated severity of mineralization problems of the future
and of facilitating objective comparison of the merits of
various ameliorative measures.
The first of the suite is the daily washoff model, designed to
simulate daily catchment runoffs and associated daily diffusesource
salt washoff. Basic input is daily meteorological data.
In the model account is taken of both surface and sub-surface
flow processes. Calibration of the model parameters for each
of the twelve sub-catchments comprising the southern PWV region
was effected with records of discharge and water quality at key
monitoring points. A relationship was established between
industrial water consumption and diffuse-source salt generation
rates by means of which pollution levels likely to arise in the
future could be predicted.
Daily fluctuations of discharge and salt concentration at any
point in the tributaries of the southern PWV region and in the
Vaal Barrage, as well as water and salt storages in the major
impoundments of the Vaal basin are simulated by means of the
daily feed-back model. A feed-back element is incorporated
which accounts for the mixing of water distributed to each of
27 sub-regions of the southern PWV catchment, the addition of
salts through usage and the routing of effluents, together with
diffuse-source washoff generated by the first model, through
the tributary system back into the Barrage. The transmission
of pollutants through the Barrage is simulated by means of a
one-dimensional, cell-type level-pool model. This model was
used to check the reliability of calibrated parameter values
used in the daily washoff model by comparing simulated daily
salt concentrations in the Vaal Barrage with those observed at
the Rand Water Board Barrage intakes.
The third model, a simplified version of the daily feed-back
model designed to operate at a monthly computational time step,
was developed to facilitate preliminary comparisons of the
various options. This coarse tlme-etep model is relatively
cheaper to run and makes pos-lble the testing of each option
with several different hydrological sequences. Economic
factors relating salt concentration in water supply to costs to
consumers have also been incorporated.
The two feed-back models were designed in such a way that a
wide variety of planning and management options could be
modelled with the minimum of programming changes.
Procedures for comparing, with the aid of the models, the
merits of various planning and management options to improve
water quality have been evolved and are illustrated by way of
example
Clinical and functional characterisation of a novel TNFRSF1A c.605T > A/V173D cleavage site mutation associated with tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), cardiovascular complications and excellent response to etanercept treatment.
Objectives: To study the clinical outcome, treatment
response, T-cell subsets and functional consequences of a
novel tumour necrosis factor (TNF) receptor type 1
(TNFRSF1A) mutation affecting the receptor
cleavage site.
Methods: Patients with symptoms suggestive of tumour
necrosis factor receptor-associated periodic syndrome
(TRAPS) and 22 healthy controls (HC) were screened for
mutations in the TNFRSF1A gene. Soluble TNFRSF1A and
inflammatory cytokines were measured by ELISAs.
TNFRSF1A shedding was examined by stimulation of
peripheral blood mononuclear cells (PBMCs) with phorbol
12-myristate 13-acetate followed by flow cytometric
analysis (FACS). Apoptosis of PBMCs was studied by
stimulation with TNFa in the presence of cycloheximide
and annexin V staining. T cell phenotypes were monitored
by FACS.
Results: TNFRSF1A sequencing disclosed a novel V173D/
p.Val202Asp substitution encoded by exon 6 in one
family, the c.194–14G.A splice variant in another and
the R92Q/p.Arg121Gln substitution in two families.
Cardiovascular complications (lethal heart attack and
peripheral arterial thrombosis) developed in two V173D
patients. Subsequent etanercept treatment of the V173D
carriers was highly effective over an 18-month follow-up
period. Serum TNFRSF1A levels did not differ between
TRAPS patients and HC, while TNFRSF1A cleavage from
monocytes was significantly reduced in V173D and R92Q
patients. TNFa-induced apoptosis of PBMCs and T-cell
senescence were comparable between V173D patients
and HC.
Conclusions: The TNFRSF1A V173D cleavage site
mutation may be associated with an increased risk for
cardiovascular complications and shows a strong
response to etanercept. T-cell senescence does not seem
to have a pathogenetic role in affected patients
Pressure-induced enhancement of superconductivity and superconducting-superconducting transition in CaC
We measured the electrical resistivity, , of superconducting
CaC at ambient and high pressure up to 16 GPa. For 8 GPa, we found
a large increase of with pressure from 11.5 up to 15.1 K. At 8 GPa,
drops and levels off at 5 K above 10 GPa. Correspondingly, the residual
increases by 200 times and the behavior
becomes flat. The recovery of the pristine behavior after depressurization is
suggestive of a phase transition at 8 GPa between two superconducting phases
with good and bad metallic properties, the latter with a lower and more
static disorder
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