[en] The magnetic-fusion energy (MFE) program, like many other scientific and engineering activities, has a need to efficiently develop complex modeling codes which combine detailed models of components to make an integrated model of a device, as well as a rich supply of legacy code that could provide the component models. There is also growing recognition in many technical fields of the desirability of steerable software: computer programs whose functionality can be changed by the user as it is run. This project had as its goals the development of two key pieces of infrastructure that are needed to combine existing code modules, written mainly in Fortran, into flexible, steerable, object-oriented integrated modeling codes for magnetic- fusion applications. These two pieces are (1) a set of tools to facilitate the interfacing of Fortran code with a steerable object-oriented framework (which we have chosen to be based on PythonlW3, an object-oriented interpreted language), and (2) a skeleton for the integrated modeling code which defines the relationships between the modules. The first of these activities obviously has immediate applicability to a spectrum of projects; the second is more focussed on the MFE application, but may be of value as an example for other applications

[en] This case study tests the possibility of prediction for 'success' (or 'winner') components of four stock and shares market indices in a time period of three years from 02-Jul-2009 to 29-Jun-2012.We compare their performance ain two time frames: initial frame three months at the beginning (02/06/2009-30/09/2009) and the final three month frame (02/04/2012-29/06/2012).To label the components, average price ratio between two time frames in descending order is computed. The average price ratio is defined as the ratio between the mean prices of the beginning and final time period. The 'winner' components are referred to the top one third of total components in the same order as average price ratio it means the mean price of final time period is relatively higher than the beginning time period. The 'loser' components are referred to the last one third of total components in the same order as they have higher mean prices of beginning time period. We analyse, is there any information about the winner-looser separation in the initial fragments of the daily closing prices log-returns time series.The Leave-One-Out Cross-Validation with k-NN algorithm is applied on the daily log-return of components using a distance and proximity in the experiment. By looking at the error analysis, it shows that for HANGSENG and DAX index, there are clear signs of possibility to evaluate the probability of long-term success. The correlation distance matrix histograms and 2-D/3-D elastic maps generated from ViDaExpert show that the 'winner' components are closer to each other and 'winner'/'loser' components are separable on elastic maps for HANGSENG and DAX index while for the negative possibility indices, there is no sign of separation

[en] A facile radiation method was developed to obtain micro-sized poly (methyl methacrylate) (PMMA) particles and create patterned coating on different substrates by a synchrotron x-ray induced dispersion polymerization. The polymerization of MMA monomer and well defined patterning was successfully realized. The produced PMMA particles and patterning were characterized by Fourier transformation infrared (FTIR), 1H-Nuclear Magnetic Resonance (NMR), and Scanning Electron Microscope (SEM). The observed patterning contrast essentially derived from a variation of size, density and morphology of particles and the type of substrate materials used

[en] The linear multifrequency-grey acceleration (LMFGA) technique is used to accelerate the iterative convergence of multigroup thermal radiation diffusion calculations in high energy density simulations. Although it is effective and efficient in one-dimensional calculations, the LMFGA method has recently been observed to significantly degrade under certain conditions in multidimensional calculations with large discontinuities in material properties. To address this deficiency, we recast the LMFGA method in terms of a preconditioned system that is solved with a Krylov method (LMFGK). Results are presented demonstrating that the new LMFGK method always requires fewer iterations than the original LMFGA method. The reduction in iteration count increases with both the size of the time step and the inhomogeneity of the problem. However, for reasons later explained, the LMFGK method can cost more per iteration than the LMFGA method, resulting in lower but comparable efficiency in problems with small time steps and weak inhomogeneities. In problems with large time steps and strong inhomogeneities, the LMFGK method is significantly more efficient than the LMFGA method

[en] Tungsten oxide nanoparticles are prepared by evaporating and oxidizing the tungsten boat in helium and oxygen atmosphere and then quenched to the liquid nitrogen temperature. The as-prepared tungsten oxide nanoparticles are porous-free with uniform size. The morphology and particle size distribution of the as-prepared and after sinter treatments tungsten oxide nanoparticles are revealed by TEM and AFM. The long-range order of these nanoparticles can be examined by X-ray diffraction technique. The as-prepared nanoparticles exhibit a mixture structure of monoclinic and hexagonal crystals. Preliminary X-ray diffraction results indicate that the hexagonal structure is transformed to monoclinic structure after annealing to above 600 deg. C. In order to better distinguish the structural properties of the tungsten oxide (WO_3-x) nanoparticles before and after annealing, the X-ray absorption spectrum technique is utilized; thus, the detailed local atomic arrangement of oxygen and/or tungsten can be determined. According to the XAS result, the shape of the W L₃-edge undergoes no considerable changes. This infers that structural transformation of tungsten oxide nanoparticle may be caused by the migration of oxygen after sintering. From the O K-edge of absorption spectrum, it suggests that a mixture phase structure is obtained when sintered below 300 deg. C. And this result indicates that heat treatment to approximately 600 deg. C produces a stable structure of a monoclinic crystal of WO₃

[en] The bearing capacity of shear stud connectors from the simplified design equations in different building codes tends to be underestimated because of a relatively large safety factor. Finite element analysis using ABAQUS was carried out to simulate the force–deformation response of shear stud. The finite element model was verified by using push-out tests, and detailed parametric numerical studies were conducted to investigate the force–deformation response of different shear stud configurations. A new design equation was derived from linear regression based on the results of the parametric studies. The presented equation shows better agreement with the experimental data. Detailed comparison between the proposed equation and existing design equation in China code for shear stud strength was carried out. The results show significant reduction in the construction cost when the new equation is used.

[en] Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace (BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis (IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio (CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building.

[en] Mn vacancy defect and grain size are shown to modify the magnetic phase diagram of MnSi significantly, especially near the critical regime of A-phase (skyrmion lattice) formation and the helimagnetic phase transition. Crystals grown using controlled nonstoichiometric initial precursors creates both grain boundaries and intrinsic Mn vacancy defect of various levels in MnSi. The results of combined transport, specific heat, and AC spin susceptibility measurements are compared for MnSi single crystal samples of various manganese deficiency levels and grain sizes. The finite-size effect and Mn vacancy level dependent helical phase transition temperature $T_{\text{c}}$ have been identified and verified. The stability of A-phase in H-T phase space has been examined through AC spin susceptibility data analysis. (paper)

[en] This study systemically investigates the retardation of electrical-stress-induced degradation in Ge₂Sb₂Te₅ (GST) by modifying its material properties through doping. The effects of doping on the electromigration and void formation in molten GST are explored by studying the model of a large and symmetric line-shaped GST cell doped with nitrogen, oxygen and bismuth, using high-amplitude electrical pulse stress. The electromigration rate, which is represented by the product of the diffusion coefficient and effective charge number (DZ^*), and the amount of void formation in doped GST are quantified and compared with undoped GST. The DZ^* and void area in Bi-doped GST increased by ∼10% compared with those in undoped GST; these values decreased by 30% and 45% in the O- and N-doped GST, respectively. The results suggest that the interstitial-type dopant could suppress the electromigration rate and void formation by decreasing the free volume; however, the substitutional-type dopant could not. The change in the free volume of molten GST due to dopants led to the change in the electromigration rate and the area of void formation. Understanding how the atomic-bonding type of dopants affects the degradation phenomena helps in designing phase-change material that is more stable against device failures.

[en] Topography and surface chemistry have a profound effect on the way in which cells interact with an implant, which in turn impacts on clinical use and performance. In this paper we examine an electrochemical polishing approach in H₂SO₄/methanol that can be applied to the widely used orthopaedic/dentistry implant material, Ti6Al4V, to produce structured surfaces. The surface roughness, as characterized by R_a, was found to be dependent on the time of electropolishing but not on the voltage parameters used here. The surface chemistry, however, was dependent on the applied electrochemical potential. It was found that the chemical composition of the surface layer was modified during the electrochemical process, and at high potentials (9.0 V) a pure TiO₂ layer of at least 10 nm was created on top of the bulk alloy. Characterization of these surfaces with rat cells from the osteoblast lineage provided further evidence of contact guidance by microscale topography with morphology analysis correlating with surface roughness (R_a 300–550 nm). Formation of a bone-like matrix after long-term culture on these surfaces was not strongly dependent upon R_a values but followed the voltage parameter. These findings suggest that the surfaces created by treatment at higher voltages (9.0 V) produced a nanoscale layer of pure TiO₂ on the Ti6Al4V surface that influenced the programme of cellular differentiation culminating in osteogenesis. (paper)