On the origins of scaling corrections in ballistic growth models

We study the ballistic deposition and the grain deposition models on two-dimensional substrates. Using the Kardar-Parisi-Zhang (KPZ) ansatz for height fluctuations, we show that the main contribution to the intrinsic width, which causes strong corrections to the scaling, comes from the fluctuations in the height increments along deposition events. Accounting for this correction in the scaling analysis, we obtained scaling exponents in excellent agreement with the KPZ class. We also propose a method to suppress these corrections, which consists in divide the surface in bins of size $\varepsilon$ and use only the maximal height inside each bin to do the statistics. Again, scaling exponents in remarkable agreement with the KPZ class were found. The binning method allowed the accurate determination of the height distributions of the ballistic models in both growth and steady state regimes, providing the universal underlying fluctuations foreseen for KPZ class in 2+1 dimensions. Our results provide complete and conclusive evidences that the ballistic model belongs to the KPZ universality class in $2+1$ dimensions. Potential applications of the methods developed here, in both numerics and experiments, are discussed.Comment: 8 pages, 7 figure

Online analyses of terrains for environment and engineering geology studies

This is an author’s version (C. Alves) and not the final published text. The final published text can be found in Proceedings 2019, 24(1), 10; https://doi.org/10.3390/IECG2019-06222Geology is, from its foundation, a subject strongly based on field studies. Nonetheless, offsite studies can frequently play a relevant role in surveying large areas and in preliminary assessments of specific sites, and they could give important contributions to the planning of onsite works. Diverse online tools, including topographic and geological maps, satellite images and onsite images (Google Street View), are freely available and can be integrated into a GIS (Geographic Information System) environment such as QGIS (A Free and Open Source Geographic Information System licensed under the GNU General Public License [1]). The potential and limitations of these tools can be discussed in the context of subjects relating to environmental and engineering geology. The discussion can be supported by some case studies related to examples of these issues, based on observations of terrains (including observations of built structures). Diverse perspectives can be considered, such as restraints to structure development, hazard assessment and hydrological studies, as well as the potential of sites to be used for the teaching of concepts related to these subjectsThe Lab2PT-Landscapes, Heritage and Territory laboratory-AUR/04509 is supported by the Portuguese FCT—“Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER co-financing, in the aim of the new partnership agreement PT2020 and COMPETE2020—POCI 010145 FEDER 007528)

A new method for the detection of singular points in fingerprint images

Automatic biometric identification based on fingerprintsis still one of the most reliable identification method in criminaland forensic applications. A critical step in fingerprintanalysis without human intervention is to automatically andreliably extract singular points from the input fingerprintimages. These singular points (cores and deltas) not onlyrepresent the characteristics of local ridge patterns but alsodetermine the topological structure (i.e., fingerprint type)and largely influence the orientation field. Poincaré Indexbasedmethods are one of the most common for singularpoints detection. However, these methods usually result inmany spurious detections. Therefore, we propose an enhancedversion of the method presented by Zhou et al. [13]that introduced a feature called DORIC to improve the detection.Our principal contribution lies in the adoption of asmoothed orientation field and in the formulation of a newalgorithm to analyze the DORIC feature. Experimental resultsshow that the proposed algorithm is accurate and robust,giving better results than the best reported results sofar, with improvements in the range of 5% to 7%

Optimization of the Anodization Processing for Aluminum Oxide Gate Dielectrics in ZnO Thin Film Transistors by Multivariate Analysis

The present study reports a two-level multivariate analysis to optimize the production of anodized aluminum oxide (Al₂O₃) dielectric films for zinc oxide thin-film transistors (TFTs). Fourteen performance parameters were measured and analysis of variance (ANOVA) of the combined responses has been applied to identify how the Al₂O₃ dielectric fabrication process influences the electrical properties of the TFTs. Using this approach, the levels for the manufacturing factors to achieve optimal overall device performance have been identified and ranked. The cross-checked analysis of the TFT performance parameters demonstrated that the appropriate control of the anodization process can have a higher impact on TFT performance than the use of traditional methods of surface treatment of the dielectric layer. Flexible electronics applications are expected to grow substantially over the next 10 years. Given the complexity and challenges of new flexible electronics components, this “multivariate” approach could be adopted more widely by the industry to improve the reliability and performance of such devices

A recongurable computing system for an autonomous sailboat

This paper presents the computing infrastructureused in an autonomous unmanned smallscalesailboat. The system is build on a reconfigurableFPGA and includes custom designed interfacesfor the various sensors and actuators usedin the sailboat. The central processing unit isa 32-bit RISC microprocessor (Microblaze fromXILINX) implemented as a soft IP (IntellectualProperty) core, running at a maximum frequencyof 50 MHz. The computing system runs uClinux,a simplified version of the popular Linux operatingsystem. The usage of a reconfigurable platformenables the possibility to reconfigure completelythe processing and control hardware system.This facilitates enormously the developmentof the control system and allows the selection ofdifferent hardware control systems, according tothe navigation requirements and environmentalconditions

UV phototransistors based upon spray coated and sputter deposited ZnO TFTs

A comparison of Zinc Oxide (ZnO) phototransistors prepared by spray and sputter coating process is presented. The work shows that spray coated layers provide significant advantages in sensor response over ZnO phototransistors made by physical vapour deposition and we show that spray deposited ZnO phototransistors can exhibit state-of-the-art performances for UV photodetectors. Topographic images of the samples surface shows that there is increase in surface roughness in spray coated samples indicating increasing grain sizes, which is considered the source of the greater sensor responsivity. X-ray photoelectron spectroscopy (XPS) is also used to understand the root cause of the greater UV responsivity. It was observed that sprayed ZnO TFTs are more sensitive to UV radiation due to higher adsorption of oxygen level. Responsivity and external quantum efficiency (EQE) of the sprayed and sputtered ZnO TFTs are also evaluated