890 research outputs found
Generation of high-energy monoenergetic heavy ion beams by radiation pressure acceleration of ultra-intense laser pulses
A novel radiation pressure acceleration (RPA) regime of heavy ion beams from
laser-irradiated ultrathin foils is proposed by self-consistently taking into
account the ionization dynamics. In this regime, the laser intensity is
required to match with the large ionization energy gap when the successive
ionization of high-Z atoms passing the noble gas configurations [such as
removing an electron from the helium-like charge state to
]. While the target ions in the laser wing region are ionized
to low charge states and undergo rapid dispersions due to instabilities, a
self-organized, stable RPA of highly-charged heavy ion beam near the laser axis
is achieved. It is also found that a large supplement of electrons produced
from ionization helps preserving stable acceleration. Two-dimensional
particle-in-cell simulations show that a monoenergetic beam
with peak energy and energy spread of is obtained by
lasers at intensity .Comment: 5 pages, 4 figure
Gastrointestinal helminthiasis presenting with acute diarrhoea and constipation: report of two cases with a second pathology.
Gastrointestinal helminthiasis in developing countries contributes to malnutrition and anemia. Diagnosis and treatment of helminthiasis, especially with low worm load is an unmet public health need in such settings. The infection may sometimes become manifest when a second pathology leads to purgation of the gastrointestinal tract. Two cases of helminthiasis are presented in which the infections only became amenable to diagnosis due to acute diarrhoea caused by giardiasis and lactulose administration. In the first case, acute giardiasis revealed Ascaris lumbricoides infestation, and in the second case primary helminthiasis (strongyloidiasis) was revealed by lactulose, and also led to Vibrio cholera bacteremia. These cases highlight the need to diagnose helminth infestations especially with low worm burdens by means of public health surveillance programmes. These cases highlight the need to diagnose helminth infestations especially with low worm burdens by means of public health surveillance programmes
Investigation of the Flow Field inside a Drainage System: Gully - Pipe - Manhole
Gully drop connected with manhole is one crucial structural part in several urban drainage systems. This paper analyses the flow pattern and flow hydraulics of a gully-manhole drainage structure. Analysis is done numerically using computational fluid dynamics CFD tools OpenFOAM®. Data from the Dual Drainage / Multi Link Element installation (DD-MLE) at the University of Coimbra hydraulic lab is used to validate the numerical simulations. The experimental model setup consists of a 0.5 m wide channel, a 0.6 × 0.24 × 0.32 m (L × W × D) gully, a gully outlet with an 80 mm diameter pipe and a manhole of 1 m diameter with a 300 mm inlet and outlet pipe connected. The flow pattern is observed under drainage flow conditions with different surcharge heights of the manhole. It has been observed that the intercepted flow through the gully decreases with the increase of surcharge in the manhole. The shear stress at the gully floor is found much higher than that of manhole floor. This indicates the probability that bigger sediment particle can be transported through gully but will remain deposited at the manhole floor. The flow pattern in the manhole changes with the change of surcharge height. The flow through the manhole inlet seems to disperse less at higher surcharge
Heavy quark supermultiplet excitations
Lorentz covariant wave functions for meson and baryon supermultiplets are
simply derived by boosting representations corresponding to
multiquark systems at rest.Comment: 12 pages (Revtex), UTAS-PHYS-93-4
Left-right symmetry in 5D and neutrino mass in TeV scale gravity models
We construct a left-right symmetric model based on the gauge group
in five dimensions where both the
gauge bosons and fermions reside in all five dimensions. The orbifold boundary
conditions are used not only to break the gauge symmetry down to but also to ``project'' the right handed neutrino out
of the zero mode part of the spectrum, providing a new way to understand the
small neutrino masses without adding (singlet) bulk neutrinos. This formulation
of the left-right model has also two new features: (i) it avoids most existing
phenomenological bounds on the scale of the right handed boson allowing
for the possibility that the right handed gauge bosons could have masses under
a TeV, and (ii) it predicts a stable lepton with mass of order of the inverse
radius of the fifth dimension.Comment: 20 pages; some new materials and references adde
Higgs Search : Present and Future
In this talk I review theoretical bounds on mass of the Higgs scalar in the
Standard Model(SM) and then summarise current experimental limits from the LEP
experiments. Following this I discuss the search strategies for the SM Higgs at
LEP 200 and the TeV energy \eplem\ colliders which are under discussion. This
will be followed by a summary of the Higgs search potential of the pp
supercolliders such as SSC/LHC. I then close with a brief discussion of a `Dark
Higgs' whose dominant decay modes are into invisible channels.Comment: 22 pages, 14 figures, available on request. Latex, needs
equation.sty, added at the end of manuscript. BU-TH-93/
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