Enthalpy and total energy vs. elevation in the Italian Alps

In this work quarterly and yearly averages of enthalpy and total energy (moist static energy) of air were calculated from literature climatological data of 21 weather stations in the Italian Alps, at altitudes ranging from 200 to 3500 m a.s.l., and it was verified that the mean total energy is almost invariant with elevation, as previously found in North America, and there is no obvious difference between easterly or westerly sections of the Alps. The invariance with the elevation of the total energy for unit mass of air can be implied from the hydrostatic equilibrium in the adiabatic case. When averaged over three months or a year, positive and negative energy inputs level out, and mean total energy is almost altitudinally and zonally invariant

Wind speed and thermal gradient in a moderately stable PBL

In the inertial layer of a moderately stable BL (0 < Ri < 0.2) the M.O. similarity theory gives the profiles of wind speed U and thermal gradient Δϑ as functions of the dimensionless height ζ = z/L. Experimental works permit to evaluate ζ and the similarity functions Ψm and Ψh from Ri. Giving the correct values for z0 and u∗ if Δϑ known it is possible to calculate U(z) at any z contained in the inertial layer. This relationship is used to explain the clustering of values of U and ΔT/Δz measured at two stacks of a TWA power plant

Unusual polymerization in the Li4C60 fulleride

Li4C60, one of the best representatives of lithium intercalated fullerides, features a novel type of 2D polymerization. Extensive investigations, including laboratory x-ray and synchrotron radiation diffraction, 13C NMR, MAS and Raman spectroscopy, show a monoclinic I2/m structure, characterized by chains of [2+2]-cycloaddicted fullerenes, sideways connected by single C-C bonds. This leads to the formation of polymeric layers, whose insulating nature, deduced from the NMR and Raman spectra, denotes the complete localization of the electrons involved in the covalent bonds.Comment: 7 pages, 6 figures, RevTex4, submitted to Phys. Rev.

Interfacing Sca-1pos Mesenchymal Stem Cells with Biocompatible Scaffolds with Different Chemical Composition and Geometry

An immortalized murine mesenchymal stem cell line (mTERT-MSC) enriched for Linneg/Sca-1pos fraction has been obtained through the transfection of MSC with murine TERT and single-cell isolation. Such cell line maintained the typical MSC self-renewal capacity and continuously expressed MSC phenotype. Moreover, mTERT-MSC retained the functional features of freshly isolated MSC in culture without evidence of senescence or spontaneous differentiation events. Thus, mTERT-MSC have been cultured onto PLA films, 30 and 100 μm PLA microbeads, and onto unpressed and pressed HYAFF-11 scaffolds. While the cells adhered preserving their morphology on PLA films, clusters of mTERT-MSC were detected on PLA beads and unpressed fibrous scaffolds. Finally, mTERT-MSC were not able to colonize the inner layers of pressed HYAFF-11. Nevertheless, such cell line displayed the ability to preserve Sca-1 expression and to retain multilineage potential when appropriately stimulated on all the scaffolds tested

Regulatory Novelty after Financial Crises: A Quantitative Text Analysis of International Banking and Securities Standards, 1975-2016

Financial crises are often understood as triggers for important innovations in international regulation of financial markets, but existing studies primarily rely on evidence from individual initiatives, assessed against noncomparable benchmarks. In order to provide systematic evidence of financial crises’ impact on international financial regulatory change, this paper develops a novel text-as-data approach to measure regulatory novelty. We use this approach to analyze the full population of international banking and securities standards between 1975 and 2016. Contrary to theoretical expectations, our empirical findings indicate rules designed by international banking and securities regulators following financial crises are often as likely to build on and adapt existing international regulations as those designed before a crisis. We also find international banking rules published after the 2008 Global Financial Crisis are an important exception. This paper provides unique insights into the evolution of global financial rules and a general approach for analyzing regulatory change

Channel-wise Mixed-precision Assignment for DNN Inference on Constrained Edge Nodes

Quantization is widely employed in both cloud and edge systems to reduce the memory occupation, latency, and energy consumption of deep neural networks. In particular, mixed-precision quantization, i.e., the use of different bit-widths for different portions of the network, has been shown to provide excellent efficiency gains with limited accuracy drops, especially with optimized bit-width assignments determined by automated Neural Architecture Search (NAS) tools. State-of-The-Art mixed-precision works layer-wise, i.e., it uses different bit-widths for the weights and activations tensors of each network layer. In this work, we widen the search space, proposing a novel NAS that selects the bit-width of each weight tensor channel independently. This gives the tool the additional flexibility of assigning a higher precision only to the weights associated with the most informative features. Testing on the MLPerf Tiny benchmark suite, we obtain a rich collection of Pareto-optimal models in the accuracy vs model size and accuracy vs energy spaces. When deployed on the MPIC RISC-V edge processor, our networks reduce the memory and energy for inference by up to 63% and 27% respectively compared to a layer-wise approach, for the same accuracy

A Semi-Empirical Model of PV Modules Including Manufacturing I-V Mismatch

This paper presents an analysis of the impact of manufacturing variability in PV modules when interconnected into a large PV panel. The key enabling technology is a compact semiempirical model, that is built solely from information derived from datasheets, without requiring extraction of electrical parameters or measurements. The model explicits the dependency of output power on those quantities that are heavily affected by variability, like short circuit current and open circuit voltage. In this way, variability can be included with Monte Carlo techniques and tuned to the desired distributions and tolerance. In the experimental results, we prove the effectiveness of the model in the analysis of the optimal interconnection of PV modules, with the goal of reducing the impact of variability

Multiscale three-dimensional scaffolds for soft tissue engineering via multimodal electrospinning

A novel (scalable) electrospinning process was developed to fabricate bio-inspired multiscale three-dimensional scaffolds endowed with a controlled multimodal distribution of fiber diameters and geared towards soft tissue engineering. The resulting materials finely mingle nano- and microscale fibers together, rather than simply juxtaposing them, as is commonly found in the literature. A detailed proof of concept study was conducted on a simpler bimodal poly(ε-caprolactone) (PCL) scaffold with modes of fiber distribution at 600 nm and 3.3 μm. Three conventional unimodal scaffolds with mean diameters of 300 nm and 2.6 and 5.2 μm, respectively, were used as controls to evaluate the new materials. Characterization of the microstructure (i.e. porosity, fiber distribution and pore structure) and mechanical properties (i.e. stiffness, strength and failure mode) indicated that the multimodal scaffold had superior mechanical properties (Young's modulus ∼40 MPa and strength ∼1 MPa) in comparison with the controls, despite the large porosity (∼90% on average). A biological assessment was conducted with bone marrow stromal cell type (mesenchymal stem cells, mTERT-MSCs). While the new material compared favorably with the controls with respect to cell viability (on the outer surface), it outperformed them in terms of cell colonization within the scaffold. The latter result, which could neither be practically achieved in the controls nor expected based on current models of pore size distribution, demonstrated the greater openness of the pore structure of the bimodal material, which remarkably did not come at the expense of its mechanical properties. Furthermore, nanofibers were seen to form a nanoweb bridging across neighboring microfibers, which boosted cell motility and survival. Lastly, standard adipogenic and osteogenic differentiation tests served to demonstrate that the new scaffold did not hinder the multilineage potential of stem cells. © 2009 Acta Materialia Inc