The Influence of Halide Substituents on the Structural and Magnetic Properties of Fe6_{6}Dy3_{3} Rings

We report the synthesis and magnetic properties of three new nine-membered Fe(III)-Dy(III) cyclic coordination clusters (CCCs), with a core motif of [Fe$_{6}$Dy$_{3}$(μ-OMe)$_{9}$(vanox)$_{6}$(X-benz)$_{6}$] where the benzoate ligands are substituted in the para-position with X = F (1), Cl (2), Br (3). Single crystal X-ray diffraction structure analyses show that for the smaller fluorine or chlorine substituents the resulting structures exhibit an isostructural Fe$_{6}$Dy$_{3}$ core, whilst the 4-bromobenzoate ligand leads to structural distortions which affect the dynamic magnetic behavior. The magnetic susceptibility and magnetization of 1-3 were investigated and show similar behavior in the dc (direct current) magnetic data. Additional ac (alternating current) magnetic measurements show that all compounds exhibit frequency-dependent and temperature-dependent signals in the in-phase and out-of-phase component of the susceptibility and can therefore be described as field-induced SMMs. The fluoro-substituted benzoate cluster 1 shows a magnetic behavior closely similar to that of the corresponding unsubstituted Fe$_{6}$Dy$_{3}$ cluster, with U$_{eff}$ = 21.3 K within the Orbach process. By increasing the size of the substituent toward 4-chlorobenzoate within 2, an increase of the energy barrier to U$_{eff}$ = 36.1 K was observed. While the energy barrier becomes higher from 1 to 2, highlighting that the introduction of different substituents on the benzoate ligand in the para-position has an impact on the magnetic properties, cluster 3 shows a significantly different SMM behavior where U$_{eff}$ is reduced in the Orbach regime to only 4.9 K

The First Use of a ReX5_{5} Synthon to Modulate FeIII^{III} Spin Crossover via Supramolecular Halogen⋅⋅⋅Halogen Interactions

We have added the {Re$^{IV}$X$_{5}$}$^{−}$ (X=Br, Cl) synthon to a pocket‐based ligand to provide supramolecular design using halogen⋅⋅⋅halogen interactions within an Fe$^{III}$ system that has the potential to undergo spin crossover (SCO). By removing the solvent from the crystal lattice, we “switch on” halogen⋅⋅⋅halogen interactions between neighboring molecules, providing a supramolecular cooperative pathway for SCO. Furthermore, changes to the halogen‐based interaction allow us to modify the temperature and nature of the SCO event

System Size and Energy Dependence of Near-Side Dihadron Correlations

Two-particle azimuthal (Δφ) and pseudorapidity (Δη) correlations using a trigger particle with large transverse momentum (PT)in d+Au, Cu+Cu, and Au+Au collisions at √ sNN = 62.4 GeV and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider are presented. The near-side correlation is separated into a jet-like component, narrow in both Δφ and Δη, and the ridge, narrow in Δφ but broad in Δη. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated PT. The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at √ sNN = 200 GeV, is also found in Cu+Cu collisions and in collisions at √ sNN = 62.4 GeV, but is found to be substantially smaller at √ sNN = 62.4 GeV than at √ sNN = 200 GeV for the same average number of participants (Npart ). Measurements of the ridge are compared to models

Coal/Biomass Fuels and the Gas Turbine: Utilization of Solid Fuels and Their Derivatives

This paper discusses key design and development issues in utilizing coal and other solid fuels in gas turbines. These fuels may be burned in raw form or processed to produce liquids or gases in more or less refined forms. The use of such fuels in gas turbines requires resolution of technology issues which are of little or no consequence for conventional natural gas and refined oil fuels. For coal, these issues are primarily related to the solid form in which coal is naturally found and its high ash and contaminant levels. Biomass presents another set of issues similar to those of coal. Among the key areas discussed are effects of ash and contaminant level on deposition, corrosion, and erosion of turbine hot parts, with particular emphasis on deposition effects

ρ0 Photoproduction in AuAu Collisions at √ sNN = 62.4 GeV Measured With the STAR Detector

Vector mesons may be photoproduced in relativistic heavy-ion collisions when a virtual photon emitted by one nucleus scatters from the other nucleus, emerging as a vector meson. The STAR Collaboration has previously presented measurements of coherent ρ0 photoproduction at center of mass energies of 130 GeV and 200 GeV in AuAu collisions. Here, we present a measurement of the cross section at 62.4 GeV; we find that the cross section for coherent ρ0 photoproduction with nuclear breakup is 10.5 ± 1.5 ± 1.6mb at 62.4 GeV. The cross-section ratio between 200 GeV and 62.4 GeV is 4.4 ± 0.6, less than is predicted by most theoretical models. It is, however, proportionally much larger than the previously observed 15% ± 55% increase between 130 GeV and 200 GeV

Syntheses, Crystal Structure, Electrocatalytic, and Magnetic Properties of the Monolanthanide-Containing Germanotungstates [Ln(H2_{2}O)n_{n}GeW11_{11}O39_{39}]5−^{5-} (Ln = Dy, Er, n = 4,3)

Two monolanthanide-containing polyanions based on monolacunary Keggin germanotungstates [Ln(H2O)nGeW11O39]5− (Ln = Dy, Er, n = 4,3) have been synthesized in simple one-pot synthetic procedure and compositionally characterized in solid state by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. Electronic absorption and emission spectra of the title compounds in solution were also studied. The [DyIII(H2O)4GeW11O39]5− Keggin POM exhibits a slow relaxation of magnetization. The cyclic voltammetry measurements and mass spectrometry were carried out to check the stability of the compounds in solution. Both polyanions prove efficient in the electrocatalytic reduction of nitrite. To our knowledge, this observation establishes the first example of electrocatalysis of nitrite reduction by all inorganic monolanthanidecontaining germanotungstates family

Single Spin Asymmetry AN in Polarized Proton–Proton Elastic Scattering at √s = 200 GeV

We report a high precision measurement of the transverse single spin asymmetry AN at the center of mass energy √s = 200 GeV in elastic proton–proton scattering by the STAR experiment at RHIC. The AN was measured in the four-momentum transfer squared t range 0.003 ⩽ | t | ⩽ 0.035 ( GeV / c ) 2 , the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of AN and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this √s, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton–proton elastic scattering

Indirect inguinal hernia masquerading as a Spigelian hernia

Inguinal hernia usually developed and descended into scrotum. The clinical presentation is inguinal or inguino-scrotal swelling. Abdominal wall weakness as it is frequently seen in African tropical zones produces often rare clinical case. We report a case of inguinal hernia presented as an abdominal wall swelling clinically suggestive of a Spigelian hernia and discuss the mechanism

J/Ѱ polarization in p+p collisions at √s = 200 GeV in STAR

We report on a polarization measurement of inclusive J/Ѱ mesons in the di-electron decay channel at mid-rapidity at 2 \u3c pT \u3c 6 GeV/c in p + p collisions at √s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/Ѱ polarization measurement should help to distinguish between different models of the J/Ѱ production mechanism since they predict different pT dependences of the J/Ѱ polarization. In this analysis, J/Ѱ is studied in the helicity frame. The polarization parameter λθ measured at RHIC becomes smaller towards high pT, indicating more longitudinal J/Ѱ polarization as pT increases. The result is compared with predictions of presently available models

Beam-Energy-Dependent Two-Pion Interferometry and the Freeze-Out Eccentricity of Pions Measured in Heavy Ion Collisions at the STAR Detector

We present results of analyses of two-pion interferometry in Au+Au collisions at √SNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown–Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model