Localized states at zigzag edges of bilayer graphene

We report the existence of zero energy surface states localized at zigzag edges of bilayer graphene. Working within the tight-binding approximation we derive the analytic solution for the wavefunctions of these peculiar surface states. It is shown that zero energy edge states in bilayer graphene can be divided into two families: (i) states living only on a single plane, equivalent to surface states in monolayer graphene; (ii) states with finite amplitude over the two layers, with an enhanced penetration into the bulk. The bulk and surface (edge) electronic structure of bilayer graphene nanoribbons is also studied, both in the absence and in the presence of a bias voltage between planes.Comment: 4 pages, 5 figure

Bilayer graphene: gap tunability and edge properties

Bilayer graphene -- two coupled single graphene layers stacked as in graphite -- provides the only known semiconductor with a gap that can be tuned externally through electric field effect. Here we use a tight binding approach to study how the gap changes with the applied electric field. Within a parallel plate capacitor model and taking into account screening of the external field, we describe real back gated and/or chemically doped bilayer devices. We show that a gap between zero and midinfrared energies can be induced and externally tuned in these devices, making bilayer graphene very appealing from the point of view of applications. However, applications to nanotechnology require careful treatment of the effect of sample boundaries. This being particularly true in graphene, where the presence of edge states at zero energy -- the Fermi level of the undoped system -- has been extensively reported. Here we show that also bilayer graphene supports surface states localized at zigzag edges. The presence of two layers, however, allows for a new type of edge state which shows an enhanced penetration into the bulk and gives rise to band crossing phenomenon inside the gap of the biased bilayer system.Comment: 8 pages, 3 fugures, Proceedings of the International Conference on Theoretical Physics: Dubna-Nano200

The vernacular house between the Cávado and the Ave, Portugal

Publicado em "Vernacular heritage and earthen architecture : contributions for sustainable development", ISBN 978-1-138-00083-4With acknowledged authenticity and cultural heritage value, rural vernacular construction of Entre-Douro-e-Minho represents the results of the centuries-old relation between men and available natural resources. Abandoned or victim of armful interventions, this unique heritage acquired economi- cal value by the growing interest on rural environment and life. It represents a mean to economical and social boosting of these depressed areas, but at the same time exposing them to the threatening lack of knowledge and property speculation. In order to protect and prevent future damages to this fragile herit- age, it’s fundamental the study and identification of its identity and technical-constructive key features. This paper presents the results of a fieldwork study performed between the Cávado and Ave rivers, which aimed to identify morfo-typologies, materials and construction techniques of the existent schist heritage. The data collected aims to contribute to its preservation and to assist technicians in future rehabilitation projects in the area

A new genus, Atlanteuptychia gen. nov., for Euptychia ernestina (Lepidoptera: Nymphalidae: Satyrinae)

Atlanteuptychia Freitas, Barbosa & Mielke, gen. nov. is proposed for Euptychia ernestina Weymer, 1911 and illustrated. This taxon lacks the posterior projection of the tegumen, a synapomorphy of Euptychia Hübner, 1818, and does not share morphological synapomorphies with Cyllopsis R. Felder, 1869 and Paramacera Butler, 1868, two Central American genera apparently closely related to Euptychia ernestina, based on molecular data. This evidence supports the proposition of a new genus endemic to the Atlantic Forest, A. ernestina stat. nov.66166

Compression and bending behavior of steel fiber reinforced self-compacting concrete

A method to design cost competitive steel fiber reinforced self-compacting concrete (SFRSCC) for precasting industrial applications is described in this paper. Since demolding the elements as soon as possible is an important requirement in this industry, the influence of the age on the resistance and toughness of the designed SFRSCC was assessed carrying out an experimental program. Based on the force-deflection relationship obtained in the three point bending notched beam tests performed according to the RILEM TC 162-TDF recommendations, the stress-crack opening relationship of the SFRSCC was determined. The influence of the SFRSCC age on the fracture parameters of this material was analyzed.Inserido no programa de pesquisa suportado pelo FEDER e o Ministério da Ciência e Tecnologia (MCT) e promovido pelo Agencia de Inovação (ADI)

Perspectives on player performance during FIFA World Cup Qatar 2022: a brief report

Changing the date of the FIFA World Cup Qatar 2022 may represent a factor to consider for the expected performance of participating players. This was due to fixture congestion at the start of the season and expected weather conditions during the competition. Thus, the main purpose of this brief report was to critically analyze the potential impact of changing the competition date and weather conditions on players’ performance. In addition, a brief description about the performance during the World Cup is also provided. For the research, the Web of Science, PubMed and SPORTDiscus databases were accessed using the primary keywords FIFA World Cup and World Soccer Cup associated with the secondary keywords match running performance, fixture congestion, fatigue and weather conditions. After applying inclusion and exclusion criteria, 52 articles were considered for analysis. The results seem to indicate that although changes were expected due to the modifications made (i.e., the competition date and scheduling congestion), the performance of the players seems not to have been affected in terms of the analyzed indicators. Furthermore, it seems possible to identify some patterns in the behavior of the teams that reached the most advanced stages of the competition.This research was founded by the Higher Institute of Educational Sciences of the Douro, by national funds (FCT—Portuguese Foundation for Science and Technology) under the project UIBD/DTP/04045/2020 and by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP— Grant number: 2021/03601-1).info:eu-repo/semantics/publishedVersio

Localized States at Zigzag Edges of Multilayer Graphene and Graphite Steps

We report the existence of zero energy surface states localized at zigzag edges of $N$-layer graphene. Working within the tight-binding approximation, and using the simplest nearest-neighbor model, we derive the analytic solution for the wavefunctions of these peculiar surface states. It is shown that zero energy edge states in multilayer graphene can be divided into three families: (i) states living only on a single plane, equivalent to surface states in monolayer graphene; (ii) states with finite amplitude over the two last, or the two first layers of the stack, equivalent to surface states in bilayer graphene; (iii) states with finite amplitude over three consecutive layers. Multilayer graphene edge states are shown to be robust to the inclusion of the next nearest-neighbor interlayer hopping. We generalize the edge state solution to the case of graphite steps with zigzag edges, and show that edge states measured through scanning tunneling microscopy and spectroscopy of graphite steps belong to family (i) or (ii) mentioned above, depending on the way the top layer is cut.Comment: 6 pages, 4 figure

Evaluación de arroz paddy y soya integral cocida en la alimentación de pollas de cría y levante (0-18 semanas)

El experimento se realizó con pollas livianas y semipesadas, en las etapas de cría y levante (0-8 y 9-18 semanas) con el fin de evaluar tres niveles de reemplazo de sorgo por arroz paddy (0,50 Y 100%) en la dieta, en combinación con torta de soya o soya integral cocida (SIC), con un arreglo factorial 3 x 2 x 2 correspondiente a 12 tratamientos con diferente número de replicaciones y 32 unidades experimentales de 56 y 49 aves respectivamente para las líneas liviana y semipesada. Se emplearon 251 pollas de la línea Dekalb-XL-Link y 220 de la línea Dekalb Warren para evaluar el efecto de las dietas de cría y levante, hasta el pico de postura. No hubo diferencias (PAn experiment was conducted with light and double purpose strains of growing-rearing pullets (0-8 and 9-18 weeks age), to evaluate the effects of the replacement (0,50 and 100%) of milo by paddy rice with whole cooked soybean (WCSB) and soybean meal (SBM) with a arrangement (3 x 2 x 2) for a total of twelve treatment and 32 experimental units of 56 and 49 light and double purpose pullets respectively. 251 light and 220 double purpose pullets were use to evaluate the effects of the growing-rearing diets phase on the laying phase. There were no differences (

The construction of the transhumance territory of the Gerês-Xurés: Vernacular heritage identification, analysis and characterization

In order to ensure survival, the rural populations of the Gerês-Xurés mountain range transboundary region developed, over centuries, a very specific system of vertical transhumance. Focus on making the most out of their natural landscape harsh conditions, human intervention shaped the territory, and gave birth to the existent and very authentic vernacular heritage, that has in the corbelled dome building technologies one of its most characteristic identity features. In the pursuit of fertile land, villages were scattered in small and compact settlements, built at lower altitude and occupied all year long. The surrounding mountain’s slopes were turned into farming terraces, and the high-altitude plateaus were for livestock and farming, thru temporary settlements built in corbelled dome structures. These vital points were interconnect by a dense network of paths and masonry walls. Although the resemblance between most of the region permanent settlements, the temporary nuclei, due to each mountain particular features, show a large morphological and functional diversity, from complex structures, like the “brandas” or the “brandas e inverneiras” system, to very simple pasture areas, like the “currais”. Understanding the high potential of this endanger vernacular heritage is a key point for its preservation, as well as its recognition by the scientific community and society in general. A previous study aimed at the “brandas” morphological and constructive characterization was presented at the Rehabend 2016. This follow-up study is focus on, in a first level, the identification and characterization of the general system main features, and, in a second level, the evaluation of this vernacular heritage main preservation threats. The research, based on case studies analysed thru fieldwork surveys, geometrical and constructive, and literature support, allowed to identify the main morphological and typological features related to the heritage elements that take part in this occupation system, and are discussed in this paper.Portuguese Science and Technology Foundation for the scholarships granted (SFRH/BD/ 86704/2012 and SFRH/BD/112646/2015). This work was supported by FCT, within ISISE, project UID/ECI/04029/201