Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires

AbstractSelf-limiting oxidation of nanowires has been previously described as a reaction- or diffusion-controlled process. In this letter, the concept of finite reactive region is introduced into a diffusion-controlled model, based upon which a two-dimensional cylindrical kinetics model is developed for the oxidation of silicon nanowires and is extended for tungsten. In the model, diffusivity is affected by the expansive oxidation reaction induced stress. The dependency of the oxidation upon curvature and temperature is modeled. Good agreement between the model predictions and available experimental data is obtained. The developed model serves to quantify the oxidation in two-dimensional nanostructures and is expected to facilitate their fabrication via thermal oxidation techniques

Segregation and mixing of granular material in industrial processes

Within the EU-funded PARDEM network mixing and segregation are studied in silos and heaps, agitated mixers and fluidized beds. A method is presented with which mixing and segregation can be characterized, adapted for quasi-static to dynamic systems and applied at the global system level as well as at the local level. This paper attempts to give an overview of the applicability of this analysis by providing three instances, being chute flow representing flow down a heap, agitated mixing and fluidization, in which the method is applied

Age biases the judgment rather than the perception of an ambiguous figure

Older participants who are briefly presented with the ‘my wife/mother-in-law’ ambiguous figure estimate its age to be higher than young participants do. This finding is thought to be the result of a subconscious social group bias that influences participants’ perception of the figure. Because people are better able to recognize similarly aged individuals, young participants are expected to perceive the ambiguous figure as a young woman, while older participants are more likely to recognize an older lady. We replicate the difference in age estimates, but find no relationship between participants’ age and their perception of the ambiguous figure. This leads us to conclude that the positive relationship between participants’ age and their age estimates of the ambiguous ‘my wife/mother-in-law’ figure is better explained by the own-age anchor effect, which holds that people use their own age as a yard stick to judge the age of the figure, regardless of whether the young woman or the older lady is perceived. Our results disqualify the original finding as an example of cognitive penetrability: the participants’ age biases thei

Computational Modeling of Human Head Conductivity

Abstract. The computational environment for estimation of unknown regional electrical conductivities of the human head, based on realistic geometry from seg-mented MRI up to 2563 resolution, is described. A finite difference alternating di-rection implicit (ADI) algorithm, parallelized using OpenMP, is used to solve the forward problem describing the electrical field distribution throughout the head given known electrical sources. A simplex search in the multi-dimensional para-meter space of tissue conductivities is conducted in parallel using a distributed system of heterogeneous computational resources. The theoretical and computa-tional formulation of the problem is presented. Results from test studies are pro-vided, comparing retrieved conductivities to known solutions from simulation. Performance statistics are also given showing both the scaling of the forward problem and the performance dynamics of the distributed search.

Final Report of the Fifth Meeting of Scientific Experts on Fish Stocks in the Central Arctic Ocean

This report provides a summary of the 5th meeting of scientific experts on Fish Stocks in the Central Arctic Ocean (FiSCAO) on October 24‐26, 2017, in Ottawa, Canada. At the request of the 10 parties negotiating on an agreement to prevent unregulated commercial fishing in the High Seas portion of the Central Arctic Ocean (CAO), participants of the 5th FiSCAO meeting were tasked with addressing four Terms of Reference, summarized below: ToR 1. Design a 1‐3 year long mapping program. ToR 2. Design a monitoring program. ToR 3. Identify human, financial, vessel/equipment resources needed for mapping and monitoring. ToR 4. Develop data collection, sharing, and hosting protocols that outline the details of what and how data shall be collected, shared, and hosted for consideration by the Parties. The 5th FiSCAO meeting included scientific representatives from seven states including Canada, the People's Republic of China, the European Union, Iceland, the Republic of Korea, the Kingdom of Norway and the United States of America. The meeting also included representatives from the International Council for the Exploration of the Sea (ICES), the North Pacific Marine Science Organization (PICES) and the Arctic Council’s Protection of the Arctic Marine Environment (PAME) and Conservation of Arctic Flora and Fauna (CAFF) working groups. The report summarizes the elements for collecting baseline data (i.e., a mapping program) in the high seas CAO to achieve the goals of documenting species distributions, relative abundances and key ecosystem parameters (ToR 1). The mapping program describes the priority areas to sample, the types of data to collect and possible data collection approaches to employ. Participants emphasized that existing planned surveys are very limited, and that significant dedicated resources will be required to implement the mapping program. The report outlines a strategy for monitoring indicators of fish stocks and ecosystem components (ToR 2). The report includes a list of existing monitoring programs and a prioritized list of indicators to detect environmental change in the high seas CAO. Further refinement of a monitoring program will use information from the mapping program (ToR 1). Participants emphasized the need to begin monitoring as soon as possible and that additional research is required to operationalize monitoring indicators. The report summarizes the preliminary cost estimates (ToR 3) to implement a mapping program to collect data in the high seas portion of the CAO using a vessel of opportunity and in the Pacific Gateway region of the CAO using an independently‐organized survey. Cost implications for the monitoring program and other scientific activities are also listed (e.g., data analysis, data management). The report includes a draft data sharing policy as the foundation for a future data sharing protocol, including the technical specifications for data sharing (ToR 4). The development of the data sharing protocol will require negotiation and legal review among the participating states. A data management and data sharing pilot study on a CAO fish database is suggested to test a framework

Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > $10^3$ confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

We present the measurement of non-photonic electron production at high transverse momentum ($p_T >$ 2.5 GeV/$c$) in $p$ + $p$ collisions at $\sqrt{s}$ = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons ($\frac{e^++e^-}{2}$) at 3 GeV/$c < p_T <~$10 GeV/$c$ from bottom and charm meson decays to be ${d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0}$ = 4.0$\pm0.5$({\rm stat.})$\pm1.1$({\rm syst.}) nb and ${d\sigma_{D\to e} \over dy_e}|_{y_e=0}$ = 6.2$\pm0.7$({\rm stat.})$\pm1.5$({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at $\sqrt{s_{NN}} = 200$ GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, $\eta/s$, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of $\eta/s$ that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.Comment: 6 pages, 3 figure