Agent-Based Knowledge Framework of Energy Planning System.

One of the important factors that support human life today is energy, which will ultimately affect the development of social life, economy, and environment. To meet the future energy needs, many countries perform energy system modeling. However, this process is complex and is fraught with difficulties and errors, such as incorrectness, inconsistency, incompleteness, and redundancy. This research aims to reduce those difficulties raising this research question: How can Agent-Oriented Analysis (AOA) alleviate several challenges of energy planning process. This research project will use the Design Science Research (DSR) method and use seven Agent-Based Modellings (ABMs) including agent model, goal model, interaction model, scenario model, organization model, role model, and environment model. The research will provide an agent-based knowledge analysis framework. Practically, it will enable energy planners in many countries to perform more effective and affordable planning

Anisotropic magnetoresistance of bulk carbon nanotube sheets

We have measured the magnetoresistance of stretched sheets of carbon nanotubes in temperatures ranging from 2 K to 300 K and in magnetic fields up to 9 T, oriented either perpendicular or parallel to the plane of the sheets. The samples have been partially aligned by post-fabrication stretching, such that the direction of stretching was either parallel or perpendicular to the direction of applied electric current. We have observed large differences between the magnetoresistance measured under the two field orientations, most pronounced at the lowest temperatures, highest fields, and for the laterally-aligned sample. Treatment of the sheets with nitric acid affects this anisotropy. We analyzed the results within the theoretical framework of weak and strong localization and concluded that the anisotropy bears the mark of a more unusual phenomenon, possibly magnetically-induced mechanical strain.Comment: 34 pages, 10 figure

Impacts of parameterized orographic drag on the Northern Hemisphere winter circulation

A recent intercomparison exercise proposed by the Working Group for Numerical Experimentation (WGNE) revealed that the parameterized, or unresolved, surface stress in weather forecast models is highly model-dependent, especially over orography. Models of comparable resolution differ over land by as much as 20% in zonal mean total subgrid surface stress (Ttot). The way Ttot is partitioned between the different parameterizations is also model-dependent. In this study, we simulated in a particular model an increase in Ttot comparable with the spread found in the WGNE intercomparison. This increase was simulated in two ways, namely by increasing independently the contributions to Ttot of the turbulent orographic form drag scheme (TOFD) and of the orographic low-level blocking scheme (BLOCK). Increasing the parameterized orographic drag leads to significant changes in surface pressure, zonal wind and temperature in the Northern Hemisphere during winter both in 10 day weather forecasts and in seasonal integrations. However, the magnitude of these changes in circulation strongly depends on which scheme is modified. In 10 day forecasts, stronger changes are found when the TOFD stress is increased, while on seasonal time scales the effects are of comparable magnitude, although different in detail. At these time scales, the BLOCK scheme affects the lower stratosphere winds through changes in the resolved planetary waves which are associated with surface impacts, while the TOFD effects are mostly limited to the lower troposphere. The partitioning of Ttot between the two schemes appears to play an important role at all time scales

High Temperature Mixed State c−c-Axis Dissipation in Low Carrier Density Y0.54Pr0.46Ba2Cu3O7−δY_{0.54}Pr_{0.46}Ba_{2}Cu_{3}O_{7-\delta}

The nature of the out-of-plane dissipation was investigated in underdoped $Y_{0.54}Pr_{0.46}Ba_{2}Cu_{3}O_{7-\delta}$ single crystals at temperatures close to the critical temperature. For this goal, temperature and angle dependent out-of-plane resistivity measurements were carried out both below and above the critical temperature. We found that the Ambegaokar-Halperin relationship [V. Ambegaokar, and B. I. Halperin, Phys. Rev. Lett. \textbf{22}, 1364 (1969)] depicts very well the angular magnetoresistivity in the investigated range of field and temperature. The main finding is that the in-plane phase fluctuations decouple the layers above the critical temperature and the charge transport is governed only by the quasiparticles. We also have calculated the interlayer Josephson critical current density, which was found to be much smaller than the one predicted by the theory of layered superconductors. This discrepancy could be a result of the d-wave symmetry of the order parameter and/or of the non BCS temperature dependence of the c-axis penetration length.Comment: Will appear in PR

Spin tunneling through an indirect barrier

Spin-dependent tunneling through an indirect bandgap barrier like the GaAs/AlAs/GaAs heterostructure along [001] direction is studied by the tight-binding method. The tunneling is characterized by the proportionality of the Dresselhaus Hamiltonians at $\Gamma$ and $X$ points in the barrier and by Fano resonances. The present results suggest that large spin polarization can be obtained for energy windows that exceed significantly the spin splitting. We also formulate two conditions that are necessary for the existence of energy windows with large polarization.Comment: 19 pages, 7 figure

The representation of the trade winds in ECMWF forecasts and reanalyses during EUREC4A

The characterization of systematic forecast errors in lower-tropospheric winds is an essential component of model improvement. This paper is motivated by a global, long-standing surface bias in the operational medium-range weather forecasts produced with the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). Over the tropical oceans, excessive easterly flow is found. A similar bias is found in the western North Atlantic trades, where the EUREC 4 A field campaign provides an unprecedented wealth of measurements. We analyze the wind bias in the IFS and ERA5 reanalysis throughout the entire lower troposphere during EUREC4 A. The wind bias varies greatly from day to day, resulting in root mean square errors (RMSEs) up to 2.5 m s(-1), with a mean wind speed bias up to -1 m s(-1) near and above the trade inversion in the forecasts and up to -0.5 m s(-1) in reanalyses. These biases are insensitive to the assimilation of sondes. The modeled zonal and meridional winds exhibit a diurnal cycle that is too strong, leading to a weak wind speed bias everywhere up to 5 km during daytime but a wind speed bias below 2 km at nighttime that is too strong. Removing momentum transport by shallow convection reduces the wind bias near the surface but leads to stronger easterly near cloud base. The update in moist physics in the newest IFS cycle (cycle 47r3) reduces the meridional wind bias, especially during daytime. Below 1 km, modeled friction due to unresolved physical processes appears to be too strong but is (partially) compensated for by the dynamics, making this a challenging coupled problem

Why is it so difficult to represent stably stratified conditions in numerical weather prediction (NWP) models?

In the 1990s, scientists at European Centre for Medium-Range Weather Forecasts (ECMWF) suggested that artificially enhancing turbulent diffusion in stable conditions improves the representation of two important aspects of weather forecasts, i.e., near-surface temperatures and synoptic cyclones. Since then, this practice has often been used for tuning the large-scale performance of operational numerical weather prediction (NWP) models, although it is widely recognized to be detrimental for an accurate representation of stable boundary layers. Here we investigate why, 20 years on, such a compromise is still needed in the ECMWF model. We find that reduced turbulent diffusion in stable conditions improves the representation of winds in stable boundary layers, but it deteriorates the large-scale flow and the near-surface temperatures. This suggests that enhanced diffusion is still needed to compensate for errors caused by other poorly represented processes. Among these, we identify the orographic drag, which influences the large-scale flow in a similar way to the turbulence closure for stable conditions, and the strength of the land-atmosphere coupling, which partially controls the near-surface temperatures. We also take a closer look at the relationship between the turbulence closure in stable conditions and the large-scale flow, which was not investigated in detail with a global NWP model. We demonstrate that the turbulent diffusion in stable conditions affects the large-scale flow by modulating not only the strength of synoptic cyclones and anticyclones, but also the amplitude of the planetary-scale standing waves

Electronic and optical properties of beryllium chalcogenides/silicon heterostructures

We have calculated electronic and optical properties of Si/BeSe$_{0.41}$Te$_{0.59}$ heterostructures by a semiempirical $sp^{3}s^{*}$ tight-binding method. Tight-binding parameters and band bowing of BeSe$_{0.41}$Te$_{0.59}$ are considered through a recent model for highly mismatched semiconductor alloys. The band bowing and the measurements of conduction band offset lead to a type II heterostucture for Si/BeSe$_{0.41}$Te$_{0.59}$ with conduction band minimum in the Si layer and valence band maximum in the BeSe$_{0.41}$Te$_{0.59}$ layer. The electronic structure and optical properties of various (Si$_{2})_{n }$/(BeSe$_{0.41}$Te$_{0.59})_{m}$ [001] superlattices have been considered. Two bands of interface states were found within the bandgap of bulk Si. Our calculations indicate that the optical edges are below the fundamental bandgap of bulk Si and the transitions are optically allowed.Comment: 16 pager, 7 figure

Obtaining and Characterization of Vitroceram by Chemical Doped ZnO for Art Mosaic

This paper presents the obtaining and the characterization of ZnO doped vitroceramic, used as photo and termoresistive pigment for art mosaic. The coprecipitation involves two sequential steps, first of ions Zn2+(aq), Cr3+(aq), Co3+(aq) and Mn3+(aq), as oxihydroxides in predetermined molar reports: 98:0,6:0,7:06, followed by maturation, forced filtration and redispersion of the granules in distilled water, after which, by ion exchange is precipitated as intergranular film of Sb3+(aq) and Bi3+(aq) ions. After forced filtration and drying, the material is subjected gradually to a thermal process, according to a curve with three levels: 20-110 °C, 110-360 °C şi 360-950 °C, with a heating rate of 3 °C/min., each level keeping a constant temperature while varying between 4 and 8 h for nanostructures processes of crystalls reform. The vitroceramic was characterized by SEM-EDX, microFTIR and termic derivatography, after treatment at 110 °C and respectively 950 °C, underlining uniformity of grains and revealing their heterojonctional structure in cross-section