Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrts_{NN}=193 GeV, Cu+Au at sqrts_{NN}=200 GeV and ...Au+Au spanning the range sqrts_{NN}=11.5-200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.
Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. ...Here, in this paper, we present second (v2) and third (v3) order azimuthal anisotropies of $K_{S}^{0}$, Φ, Λ, Ξ, and Ω at midrapidity (|y| < 1) in Au+Au collisions at $\sqrt{s_{NN}}$= 54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v$^{3/2}_{2}$ are studied and motivated by hydrodynamical calculations. The ratio of v2 of Φ mesons to that of antiprotons v2(Φ)/v2($\overline{p}$) shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.
We report high-precision measurements of the longitudinal double-spin asymmetry, ALL, for midrapidity inclusive jet and dijet production in polarized p p collisions at a center-of-mass energy of √ s ...= 200 GeV . The new inclusive jet data are sensitive to the gluon helicity distribution, Δg (x, Q2), for gluon momentum fractions in the range from x ≃ 0.05 to x ≃ 0.5, while the new dijet data provide further constraints on the x dependence of Δ g (x , Q2). The results are in good agreement with previous measurements at √ s = 200 GeV and with recent theoretical evaluations of prior world data. Our new results have better precision and thus strengthen the evidence that Δg(x,Q2) is positive for x > 0.05.
Partons traversing the strongly interacting medium produced in heavy-ion collisions are expected to lose energy depending on their color charge and mass. We measure the nuclear modification factors ...for charm- and bottom-decay electrons, defined as the ratio of yields, divided by the number of binary nucleon–nucleon collisions, in
s
NN
=
200
GeV Au+Au collisions to
p
+
p
collisions (
R
AA
), or in central to peripheral Au+Au collisions (
R
CP
). We find the bottom-decay electron
R
AA
and
R
CP
to be significantly higher than those of charm-decay electrons. Model calculations including mass-dependent parton energy loss in a strongly coupled medium are consistent with the measured data. These observations provide evidence of mass ordering of charm and bottom quark energy loss when traversing through the strongly coupled medium created in heavy-ion collisions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ion Exchange Extraction of Heavy Metals from Wastewater Sludges Al-Enezi, G.; Hamoda, M. F.; Fawzi, N.
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering,
01/2004, Letnik:
39, Številka:
2
Journal Article
Recenzirano
Heavy metals are common contaminants of some industrial wastewater. They find their way to municipal wastewaters due to industrial discharges into the sewerage system or through household chemicals. ...The most common heavy metals found in wastewaters are lead, copper, nickel, cadmium, zinc, mercury, arsenic, and chromium. Such metals are toxic and pose serious threats to the environment and public health. In recent years, the ion exchange process has been increasingly used for the removal of heavy metals or the recovery of precious metals. It is a versatile separation process with the potential for broad applications in the water and wastewater treatment field. This article summarizes the results obtained from a laboratory study on the removal of heavy metals from municipal wastewater sludges obtained from Ardhiya plant in Kuwait. Data on heavy metal content of the wastewater and sludge samples collected from the plant are presented. The results obtained from laboratory experiments using a commercially available ion exchange resin to remove heavy metals from sludge were discussed. A technique was developed to solubilize such heavy metals from the sludge for subsequent treatment by the ion exchange process. The results showed high efficiency of extraction, almost 99.9%, of heavy metals in the concentration range found in wastewater effluents and sludges. Selective removal of heavy metals from a contaminated wastewater/sludge combines the benefits of being economically prudent and providing the possibility of reuse/recycle of the treated wastewater effluents and sludges.
Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. ...Here, in this paper, we present second (v2) and third (v3) order azimuthal anisotropies of $K_{S}^{0}$, Φ, Λ, Ξ, and Ω at midrapidity (|y| < 1) in Au+Au collisions at $\sqrt{s_{NN}}$= 54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and antibaryons are presented, and ratios of v3/v$^{3/2}_{2}$ are studied and motivated by hydrodynamical calculations. The ratio of v2 of Φ mesons to that of antiprotons v2(Φ)/v2($\overline{p}$) shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on antiproton v2.
Here, we report the measurement of K*0 meson at midrapidity (|y|< 1.0) in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27 and 39 GeV collected by the STAR experiment during the RHIC ...beam energy scan (BES) program. The transverse momentum spectra, yield, and average transverse momentum of K*0 are presented as functions of collision centrality and beam energy. The K*0/K yield ratios are presented for different collision centrality intervals and beam energies. The K*0/K ratio in heavy-ion collisions are observed to be smaller than that in small system collisions (e+e and p+p). The K*0/K ratio follows a similar centrality dependence to that observed in previous RHIC and LHC measurements. The data favor the scenario of the dominance of hadronic re-scattering over regeneration for K*0 production in the hadronic phase of the medium.
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