Resistivity studies under hydrostatic pressure on a low-resistance variant of the quasi-2D organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br: quest for intrinsic scattering contributions

Resistivity measurements have been performed on a low (LR)- and high (HR)-resistance variant of the kappa-(BEDT-TTF)_2Cu[N(CN)_2]Br superconductor. While the HR sample was synthesized following the standard procedure, the LR crystal is a result of a somewhat modified synthesis route. According to their residual resistivities and residual resistivity ratios, the LR crystal is of distinctly superior quality. He-gas pressure was used to study the effect of hydrostatic pressure on the different transport regimes for both variants. The main results of these comparative investigations are (i) a significant part of the inelastic-scattering contribution, which causes the anomalous rho(T) maximum in standard HR crystals around 90 K, is sample dependent, i.e. extrinsic in nature, (ii) the abrupt change in rho(T) at T* approx. 40 K from a strongly temperature-dependent behavior at T > T* to an only weakly T-dependent rho(T) at T < T* is unaffected by this scattering contribution and thus marks an independent property, most likely a second-order phase transition, (iii) both variants reveal a rho(T) proportional to AT^2 dependence at low temperatures, i.e. for T_c < T < T_0, although with strongly sample-dependent coefficients A and upper bounds for the T^2 behavior measured by T_0. The latter result is inconsistent with the T^2 dependence originating from coherent Fermi-liquid excitations.Comment: 8 pages, 6 figure

Effect of Some Threshing Parameters on Sesame Separation

The threshing section on combine harvester or thresher machine affects grain and stalk separation performance. In this study, effect of some threshing parameters such as drum speed, feed rate and concave open on closed capsules sesame straw sieve in developed threshing unit. Threshing drums used were a rasp bar with tooth type. Three threshing drum speeds of 500, 700 and 900 min-1 (6.5, 9.1, 11.7 m/s) were used to investigations. Three feed rate as 90, 180 and 270 kg/h and three concave open as 20, 35 and 50 mm were used in this study. Four sieves were used for separation of straw. Their mesh numbers are 7, 10, 14 and 18. Results show that the best performance for separation of sesame straw were gave at the maximum drum speeds, minimum feed rates and concave opens experienced in this study

Critical aspects of the random-field Ising model

We investigate the critical behavior of the three-dimensional random-field Ising model (RFIM) with a Gaussian field distribution at zero temperature. By implementing a computational approach that maps the ground-state of the RFIM to the maximum-flow optimization problem of a network, we simulate large ensembles of disorder realizations of the model for a broad range of values of the disorder strength h and system sizes  = L3, with L ≤ 156. Our averaging procedure outcomes previous studies of the model, increasing the sampling of ground states by a factor of 103. Using well-established finite-size scaling schemes, the fourth-order’s Binder cumulant, and the sample-to-sample fluctuations of various thermodynamic quantities, we provide high-accuracy estimates for the critical field hc, as well as the critical exponents ν, β/ν, and γ̅/ν of the correlation length, order parameter, and disconnected susceptibility, respectively. Moreover, using properly defined noise to signal ratios, we depict the variation of the self-averaging property of the model, by crossing the phase boundary into the ordered phase. Finally, we discuss the controversial issue of the specific heat based on a scaling analysis of the bond energy, providing evidence that its critical exponent α ≈ 0−

Exploring the Electronic and Magnetic Properties of New Metal Halides from Bulk to Two-Dimensional Monolayer: RuX3 (X=Br, I)

Theoretical and experimental studies present that metal halogens in MX$_3$ forms can show very interesting electronic and magnetic properties in their bulk and monolayer phases. Many MX$_3$ materials have layered structures in their bulk phases, while RuBr$_3$ and RuI$_3$ have one-dimensional chains in plane. In this paper, we show that these metal halogens can also form two-dimensional layered structures in the bulk phase similar to other metal halogens, and cleavage energy values confirm that the monolayers of RuX$_3$ can be possible to be synthesised. We also find that monolayers of RuX$_3$ prefer ferromagnetic spin orientation in the plane for Ru atoms. Their ferromagnetic ground state, however, changes to antiferromagnetic zigzag state after U is included. Calculations using PBE+U with SOC predict indirect band gap of 0.70 eV and 0.32 eV for the optimized structure of RuBr$_3$ and RuI$_3$, respectively. Calculation based on the Monte Carlo simulations reveal interesting magnetic properties of RuBr$_3$, such as large Curie temperature against RuI$_3$, both in bulk and monolayer cases. Moreover, as a result of varying exchange couplings between neighboring magnetic moments, magnetic properties of RuBr$_3$ and RuI$_3$ can undergo drastic changes from bulk to monolayer. We hope our findings can be useful to attempt to fabricate the bulk and monolayer of RuBr$_3$ and RuI$_3$.Comment: 20 pages, 12 figure

Results from shallow geophysical investigations in the northwestern sector of the island of Malta

We performed geophysical investigations in the northwestern sector of the island of Malta to reconstruct velocity-depth models and provide shear-wave velocity profiles. We have chosen two sites, one located in Rabat (Malta) and another in the Golden Bay area. We used both active (seismic and electrical 2D-tomography, Multichanel Analysis of Surface Waves – MASW) and passive (2D arrays and single-station measurements using ambient noise) geophysical methods. Consistently with previous studies performed in this part of Malta, we have found that both sites are characterised by site resonance in the frequency range 1-2 Hz as an effect of the local lithostratigraphic succession that shows an impedance contrast at about 60-90 m depth. This resonance effect can have important implications on both seismic hazard as well as seismic risk evaluation of the region since the amplified frequency range coincides with the resonance frequencies typical of 5–10 storey buildings which are very diffuse in the Maltese Islands, especially after intense recent urbanization.Published41-484T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa

The XMM Cluster Survey: the interplay between the brightest cluster galaxy and the intracluster medium via AGN feedback

Using a sample of 123 X‐ray clusters and groups drawn from the XMM Cluster Survey first data release, we investigate the interplay between the brightest cluster galaxy (BCG), its black hole and the intracluster/group medium (ICM). It appears that for groups and clusters with a BCG likely to host significant active galactic nuclei (AGN) feedback, gas cooling dominates in those with T X > 2 keV while AGN feedback dominates below. This may be understood through the subunity exponent found in the scaling relation we derive between the BCG mass and cluster mass over the halo mass range 10 13 < M 500 < 10 15  M ⊙ and the lack of correlation between radio luminosity and cluster mass, such that BCG AGN in groups can have relatively more energetic influence on the ICM. The L X – T X relation for systems with the most massive BCGs, or those with BCGs co‐located with the peak of the ICM emission, is steeper than that for those with the least massive and most offset, which instead follows self‐similarity. This is evidence that a combination of central gas cooling and powerful, well fuelled AGN causes the departure of the ICM from pure gravitational heating, with the steepened relation crossing self‐similarity at T X = 2 keV. Importantly, regardless of their black hole mass, BCGs are more likely to host radio‐loud AGN if they are in a massive cluster ( T X ≳ 2 keV) and again co‐located with an effective fuel supply of dense, cooling gas. This demonstrates that the most massive black holes appear to know more about their host cluster than they do about their host galaxy. The results lead us to propose a physically motivated, empirical definition of ‘cluster’ and ‘group’, delineated at 2 keV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91324/1/j.1365-2966.2012.20764.x.pd

How young radiologists use contrast media and manage adverse reactions: an international survey

Objectives: To collect real-world data about the knowledge and self-perception of young radiologists concerning the use of contrast media (CM) and the management of adverse drug reactions (ADR). Methods: A survey (29 questions) was distributed to residents and board-certified radiologists younger than 40&nbsp;years to investigate the current international situation in young radiology community regarding CM and ADRs. Descriptive statistics analysis was performed. Results: Out of 454 respondents from 48 countries (mean age: 31.7 ± 4&nbsp;years, range 25–39), 271 (59.7%) were radiology residents and 183 (40.3%) were board-certified radiologists. The majority (349, 76.5%) felt they were adequately informed regarding the use of CM. However, only 141 (31.1%) received specific training on the use of CM and 82 (18.1%) about management ADR during their residency. Although 266 (58.6%) knew safety protocols for handling ADR, 69.6% (316) lacked confidence in their ability to manage CM-induced ADRs and 95.8% (435) expressed a desire to enhance their understanding of CM use and handling of CM-induced ADRs. Nearly 300 respondents (297; 65.4%) were aware of the benefits of contrast-enhanced ultrasound, but 249 (54.8%) of participants did not perform it. The preferred CM injection strategy in CT parenchymal examination and CT angiography examination was based on patient’s lean body weight in 318 (70.0%) and 160 (35.2%), a predeterminate fixed amount in 79 (17.4%) and 116 (25.6%), iodine delivery rate in 26 (5.7%) and 122 (26.9%), and scan time in 31 (6.8%) and 56 (12.3%), respectively. Conclusion: Training in CM use and management ADR should be implemented in the training of radiology residents. Critical relevance statement: We highlight the need for improvement in the education of young radiologists regarding contrast media; more attention from residency programs and scientific societies should be focused on training about contrast media use and the management of adverse drug reactions. Key points: • This survey investigated training of young radiologists about use of contrast media and management adverse reactions. • Most young radiologists claimed they did not receive dedicated training. • An extreme heterogeneity of responses was observed about contrast media indications/contraindications and injection strategy. Graphical Abstract: (Figure presented.