Transition metal atom adsorption on the titanium carbide MXene: trends across the periodic table for the bare and O-terminated surfaces

MXenes are a family of two-dimensional materials with great interest due to their unique properties, e.g., adjustability based on changes in their composition, structure, and surface functionality, which grant MXenes a variety of applications. One way of changing the catalytic effect of MXenes consists in adsorbing isolated metallic elements, such as transition metals (TMs), onto their surface, leading to the formation of single-atom catalysts (SAC). Herewith, the adsorption behavior of 31 TMs on the surface of two titanium carbide MXenes, viz. Ti2C and Ti2CO2, is analyzed by means of density-functional theory (DFT) calculations. We find that the oxygen surface termination causes most of the TM atoms to adsorb on a hollow site above a carbon atom, whereas on bare Ti2C, the adsorption preference follows a pattern related to groups of the Periodic Table. The interaction between the TM atoms and the surface of both Ti2C and Ti2CO2 is strong, as demonstrated by the calculated adsorption energies, which range between about -1 and -9 eV on either surface. Upon adsorption on Ti2CO2, electrons are transferred from the adatom to the MXene surface, whereas on Ti2C, the only TM atoms for which this happens are the ones in group 3 of the Periodic Table. All the other transition metal atoms become negatively charged after adsorption on Ti2C. On the oxygen-covered MXene, stronger adsorptions are accompanied by higher charge transfers. The energy barriers for TM adatom diffusion on Ti2C are very small, meaning that the adatoms can move rather freely along it. On Ti2CO2, however, higher diffusion barriers were found, many being above 1 eV, which suggests that the oxygen termination layer blocks the diffusion. On both surfaces, the highest diffusion barriers were found to correspond to the TM elements which adsorb most strongly.publishe

Uma inscrição romana de Veneza na Quinta da Cardiga (Golegã – Conventus Scallabitanus)

A revista Ficheiro Epigráfico é um suplemento da revista Conimbriga e destina-se a dar a conhecer inscrições romanas inéditas da Hispânia. Não tem periodicidade estipulada e é coordenada pelo Professor José d’Encarnação.Durante a desmontagem e intervenção de conservação e restauro de uma fonte na Quinta da Cardiga (freguesia e concelho da Golegã, distrito de Santarém), possivelmente adquirida em Veneza no princípio do século XX, verificou-se que um dos elementos apresentava parte de uma inscrição romana. Trata-se, na verdade, de uma epígrafe funerária que, pela fórmula final que nos pareceu poder reconstituir – libertis libertabusq(ue) posterisq(ue) eorum –, se enquadra, de facto, no teor das epígrafes conhecidas da Regio X, datável da 1ª metade do século I d. C

Uma inscrição romana de Veneza na Quinta da Cardiga (Golegã – Conventus Scallabitanus)

A revista Ficheiro Epigráfico é um suplemento da revista Conimbriga e destina-se a dar a conhecer inscrições romanas inéditas da Hispânia. Não tem periodicidade estipulada e é coordenada pelo Professor José d’Encarnação.Durante a desmontagem e intervenção de conservação e restauro de uma fonte na Quinta da Cardiga (freguesia e concelho da Golegã, distrito de Santarém), possivelmente adquirida em Veneza no princípio do século XX, verificou-se que um dos elementos apresentava parte de uma inscrição romana. Trata-se, na verdade, de uma epígrafe funerária que, pela fórmula final que nos pareceu poder reconstituir – libertis libertabusq(ue) posterisq(ue) eorum –, se enquadra, de facto, no teor das epígrafes conhecidas da Regio X, datável da 1ª metade do século I d. C

Coder and Decoder of Block mBnB Principally the 1B2B or Manchester

This work presents the coder and decoder of block mBnB of the type 1B2B or Manchester. In the coder 1B2B each block/word of 1 input bit is coded in the block / word of 2 output bits. In the decoder 1B2B happen the inverse, each block of 2 input bits is newly converted in the original block of 1 output bit. The coder injects in the transmission line a number of 1’s exactly equal to the number of 0’s, what guarantees a DC constant component and maximizes the transitions number.  The objective is  to implement the pair coder and decoder 1B2B so that it improves the transmission quality and increases the information security. Keywords: Block codes, Digital systems, Transmission line

Design and implementation of a wireless sensor network applied to motion capture

This paper describes the development of a wireless sensor network prototype and its application in a motion capture system based on inertial and magnetic sensors. The system presents a portable and modular architecture and allows the monitoring of several users at the same time using a single wireless network. The target application requires the wireless sensor network to operate efficiently under high loads, since it generates data intensive traffic and needs to support a high number of sensor modules. Other requirements imposed by the application are real-time operation and reliable data delivery. In order to provide the quality of service required by the application, an enhanced version of the LPRT medium access control protocol was developed and implemented in devices compliant with the IEEE 802.15.4 standard at the physical layer. Simulation results show that the proposed modifications improve the performance of the protocol. The implementation of the protocol is validated through the experimental results presented.Fundação para a Ciência e a Tecnologia (FCT) - projeto PTDC/EEA-TEL/68625/2006

An integrated framework for supporting fuzzy decision-making in networked manufacturing environments

In this paper we propose an integrated framework, based on smart objects to support fuzzy decision-making processes applied to manufacturing environments. The processes involved range from factory-production level up to higher decision-making levels, either in the context of traditional single enterprises, up to the one of supply chains and distributed and ubiquitous manufacturing environments. Therefore, the proposed framework promotes contributions for solving different kind of problems, including, among others: networked supply chain management; production planning and control; factory supervision and productivity management; real-time monitoring; data acquisition and processing. The web access via different middleware devices and tools at different process levels, along with the use of integrated algorithms and smart objects, which is possible and will promote an optimized use of knowledge and resources for supporting better decision-making. Moreover, the proposed framework also aims at promoting a wider collaboration process among various groups of stakeholders.This work was supported by FCT “Fundação para a Ciência e a Tecnologia” under the program: PEst20152020.info:eu-repo/semantics/publishedVersio

Line Codes for Communication Systems

The coder is a generic device where exist a big types diversity. In base digital systems, the coder is a device that codifies the active input position in a number, normally, binary natural. If we have N inputs they are codified with n bits, N=

Coder and Decoder of Block 3B4B with Auxiliary Channel

This work presents the coder and decoder of block 3B4B with auxiliary channel. The coder 3B4B converts an input 3 bits word in an output 4 bits word. It transmits an equal number of 1’s and 0’s to provide a DC constant component. It increases the transitions number, improves the system quality and security. The objective is also to improve the system potentialities with an auxiliary channel to monitor the communication (alarm). The main channel is real, but the auxiliary channel is fictitious. Keywords: Block codes, Digital systems, Transmission line

Coder and Decoder of Block 7B8B Simplified with Auxiliary Channel

This work presents the coder and decoder of block 7B8B simplified with auxiliary channel. The coder 7B8B converts an input 7 bits word in an output 8 bits word. It transmits approximately an equal number of 1’s and 0’s to provide a DC constant component. It increases the transitions number, improves the system quality and security. The objective is also to improve the system potentialities with an auxiliary channel to monitor the communication (alarm.) The main channel is real, but the auxiliary channel is fictitious. Keywords: Block Codes, Advanced digital systems, Transmission line

Design e validação de um modelo de reabilitação com implantes curtos

Objectives: This research intended to develop and validate a digital model that could be used to study the stresses and strains created in the different components involved in oral fixed rehabilitations with short implants. The validated model was then used to simulate a clinical- like situation. Methods: A digital model was created considering the posterior areas of the mandible. Its materialization obtained ten specimens of the experimental prototype. Seven of them were static compressive tested until failure and, for the other three, the tests were progressively interrupted, to allow the establishment of a damage sequence. On the numerical model a finite element analysis was performed with Abaqus software, under similar conditions to the experimental situation. Results: The stress pattern on the FEA and the failure location on the static test were similar. The sequence in which each part reached the yield strength was the same as that observed on the interrupted static test (resin, prosthetic framework, implants and implant screws, in this order). Due to these results, the model was considered valid. A clinical-like simulation with the validated model showed that buccal cortical bone, around the implants platform, is the weakest part of such a rehabilitation. Conclusions: This research allowed the development and validation of a computer-aided design model that can be used to study an oral fixed rehabilitation supported by short implants. For clinical purposes, it is important to refer that the highest stress and strain values were found on the cortical bone around the buccal aspect of the implants.Objetivos: O objetivo desta investigação foi o desenvolvimento e validação experimental de um modelo digital, que permita o estudo das tensões e deformações geradas nos diferentes componentes de uma reabilitação oral fixa sobre implantes curtos. O modelo obtido foi então usado para simular uma situação clinica. Métodos: Um modelo numérico foi criado considerando a região posterior da mandibula. A sua materialização permitiu obter dez amostras do protótipo experimental. Sete delas foram sujeitas a ensaios estáticos de compressão até à falência. Nas restantes três, os ensaios foram interrompidos com forças gradualmente crescentes, estabelecendo a sequência pela qual os componentes se deformaram. O modelo numérico foi também sujeito a uma simulação com elementos finitos, usando o software Abaqus, em condições semelhantes à simulação experimental. Resultados: O padrão de tensões obtido no modelo numérico foi similar à localização das fraturas no modelo experimental. A sequência segundo a qual a tensão de cedência foi alcançada em cada parte do modelo numérico foi a mesma encontrada quando o ensaio estático se interrompeu (por esta ordem: resina, prótese, implantes e parafusos). Estes resultados permitiram considerar o modelo válido. A simulação de uma situação clínica, com o modelo validado, revelou que o osso cortical, em vestibular da plataforma dos implantes, é a região mais débil da reabilitação. Conclusões: Esta investigação permitiu o desenvolvimento e a validação de um modelo que permite o estudo de reabilitações fixas sobre implantes curtos. Clinicamente é importante realçar que o osso cortical é a zona que apresenta tensões e deformações mais elevadas. (Rev Port Estomatol Med Dent Cir Maxilofac. 2017;58(2):79-90)info:eu-repo/semantics/publishedVersio