Peat fuels representing four biomes of boreal (western Russia and Siberia), temperate (northern Alaska, USA), subtropical (northern and southern Florida, USA), and tropical (Borneo, Malaysia) regions ...were burned in a laboratory chamber to determine gas and particle emission factors (EFs). Tests with 25 % fuel moisture were conducted with predominant smoldering combustion conditions (average modified combustion efficiency (MCE) =0.82±0.08). Average fuel-based EFCO2 (carbon dioxide) are highest (1400 ± 38 g kg−1) and lowest (1073 ± 63 g kg−1) for the Alaskan and Russian peats, respectively. EFCO (carbon monoxide) and EFCH4 (methane) are ∼12 %–15 % and ∼0.3 %–0.9 % of EFCO2, in the range of 157–171 and 3–10 g kg−1, respectively. EFs for nitrogen species are at the same magnitude as EFCH4, with an average of 5.6 ± 4.8 and 4.7 ± 3.1 g kg−1 for EFNH3 (ammonia) and EFHCN (hydrogen cyanide); 1.9±1.1 g kg−1 for EFNOx (nitrogen oxides); and 2.4±1.4 and 2.0 ± 0.7 g kg−1 for EFNOy (total reactive nitrogen) and EFN2O (nitrous oxide). An oxidation flow reactor (OFR) was used to simulate atmospheric aging times of ∼2 and ∼7 d to compare fresh (upstream) and aged (downstream) emissions. Filter-based EFPM2.5 varied by > 4-fold (14–61 g kg−1) without appreciable changes between fresh and aged emissions. The majority of EFPM2.5 consists of EFOC (organic carbon), with EFOC ∕ EFPM2.5 ratios in the range of 52 %–98 % for fresh emissions and ∼14 %–23 % degradation after aging. Reductions of EFOC (∼7–9 g kg−1) after aging are most apparent for boreal peats, with the largest degradation in low-temperature OC1 that evolves at < 140 ∘C, indicating the loss of high-vapor-pressure semivolatile organic compounds upon aging. The highest EFLevoglucosan is found for Russian peat (∼16 g kg−1), with ∼35 %–50 % degradation after aging. EFs for water-soluble OC (EFWSOC) account for ∼20 %–62 % of fresh EFOC. The majority (> 95 %) of the total emitted carbon is in the gas phase, with 54 %–75 % CO2, followed by 8 %–30 % CO. Nitrogen in the measured species explains 24 %–52 % of the consumed fuel nitrogen, with an average of 35 ± 11 %, consistent with past studies that report ∼1/3 to 2∕3 of the fuel nitrogen measured in biomass smoke. The majority (> 99 %) of the total emitted nitrogen is in the gas phase, with an average of 16.7 % as NH3 and 9.5 % as HCN. N2O and NOy constituted 5.7 % and 2.9 % of consumed fuel nitrogen. EFs from this study can be used to refine current emission inventories.
We present
π
−
Ξ
correlation analysis in Au-Au collisions at
S
N
N
=
200
G
e
V
and
S
N
N
=
62.4
G
e
V
, performed using the STAR detector at RHIC. A
Ξ
*
(1530) resonance signal is observed for the ...first time in Au-Au collisions. Experimental data are compared with theoretical predictions. The strength of the
Ξ
*
peak is reproduced in the correlation function assuming that
π and Ξ emerge from a system in collective expansion.
We report the STAR measurement of ϕ meson production in Au+Au and p+p collisions at sNN=200GeV. Using the event mixing technique, the ϕ spectra and yields are obtained at mid-rapidity for five ...centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the ϕ transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that ϕ production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions (〈Nbin〉). The systematics of 〈pt〉 versus centrality and the constant ϕ/K− ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for ϕ production.
We report the STAR measurement of Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi spectra and yields are obtained at mid-rapidity for ...five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the Phi transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that Phi production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions. The systematics of versus centrality and the constant Phi/K- ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for Phi production.
Preliminary results on inclusive neutral pion production in d-Au collisions at
s
NN
=
200
GeV
in the pseudo-rapidity range
0
<
η
<
1
are presented. The measurement is performed using the STAR Barrel ...Electromagnetic Calorimeter (BEMC). In this paper, the analysis of the first BEMC hadron measurement is described and the results are compared with earlier RHIC findings. The
π
0
invariant differential cross sections show good agreement with next-to-leading order (NLO) perturbative QCD calculations.
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