Scaling solutions of wiggly cosmic strings: II. Time-varying coarse-graining scale solutions

We continue our exploration of the wiggly generalisation of the Velocity-Dependent One Scale Model for cosmic strings, through the study of its allowed asymptotic scaling solutions. We extend the work of a previous paper [Almeida $\&$ Martins, Phys. Rev. D 104 (2021) 043524] by considering the more comprehensive case of a time-varying coarse-graining scale for the string wiggles. The modeling of the evolution of the network therefore relies on three main mechanisms: Hubble expansion, energy transfer mechanisms (e.g., the production of loops and wiggles) and the choice of the scale at which wiggles are coarse-grained. We analyse the role of each of them on the overall behaviour of the network, and thus in the allowed scaling solutions. In Minkowski space, we find that linear scaling, previously observed in numerical simulations without expansion, is not possible with a changing averaging scale. For expanding universes, we find that the three broad classes of scaling solutions -- with the wiggliness disappearing, reaching scaling, or growing -- still exist but are differently impacted by the time evolution of the coarse-graining scale. Nambu-Goto type solutions (without wiggles) are unaffected, growing wiggliness solutions are trivially generalized, while for solutions where wiggliness reaches scaling the expansion rate for which the solution exists is decreased with respect to the one for a fixed coarse-graining scale. Finally, we also show that the inclusion of a time-varying coarse-graining scale allows, in principle, for additional scaling solutions which, although mathematically valid, are not physical. Overall, our mapping of the landscape of the allowed scaling solutions of the wiggly Velocity-Dependent One Scale Model paves the way for the detailed testing of the model, to be done by forthcoming high-resolution field theory and Nambu-Goto simulations.Comment: 15 pages, 6 figures, 1 table; Phys. Rev. D (in press). Second paper in a series, the first one is arXiv: 2107.11653. Some particular solutions were previously reported in a conference proceedings at arXiv:2210.0846

ROAZ Autonomous Surface Vehicle Design and Implementation

The design of an Autonomous Surface Vehicle for operation in river and estuarine scenarios is presented. Multiple operations with autonomous underwater vehicles and support to AUV missions are one of the main design goals in the ROAZ system. The mechanical design issues are discussed. Hardware, software and implementation status are described along with the control and navigation system architecture. Some preliminary test results concerning a custom developed thruster are presented along with hydrodynamic drag calculations by the use of computer fluid dynamic methods

Flexible time-triggered protocol for CAN: new scheduling and dispatching solutions

One of the possibilities to build robust communication systems with respect to their temporal behaviour is to use autonomous control based on the time-triggered paradigm. The FTT-CAN - flexible time-triggered protocol, relies on centralised scheduling but makes use of the CAN native distributed arbitration to reduce communication overhead. There, a planning scheduler is used within a master node to reduce the scheduling run-time overhead. On-line changes to the communication requirements can then be made under guaranteed timeliness. In addition FTT-CAN also allows an efficient combination of both time-triggered and event- triggered traffic with temporal isolation. In this paper, recent evolutions of the initial protocol definition concerning transmission of synchronous and asynchronous messages are presented. These consist in a time division of the elementary transmission window which optimises the available bandwidth for asynchronous messages, keeping the timeliness of synchronous messages without jeopardising their transmission jitter. A novel solution for the planning scheduler is also presented. It consists in an FPGA-based coprocessor which implements the planning scheduler technique without imposing overhead to the arbiter CPU. With it, it is possible to reduce strongly the plan duration thus allowing on-line admission demanded by system elements and, also, to extend the protocol application to high-speed networks

An information system for air quality monitoring using mobile sensor networks

Engineering the information system that runs a heterogeneous mobile sensor network is a complex task. In this paper we present the solution that was developed in the context of the ExpoLIS project. The goal of this project is to deploy a network of mobile (low-cost) sensors in city buses. Besides the software that needs to transfer, process, and store sensor data, we also developed a mobile application to increase awareness on air pollution, and a tool that allows scientists to subscribe to sensor data. We present the engineering solutions that form the backbone of the information system, and the structure and design of developing supporting tools. We discuss our choices regarding how sensor data are processed in order to make these data available for the common citizen. We mention possible future directions for the software that we have developed.info:eu-repo/semantics/acceptedVersio

Marine Operations with the SWORDFISH Autonomous Surface Vehicle

IEEE Robótica 2007 - 7th Conference on Mobile Robots and Competitions, Paderne, Portugal 2007This paper describes the design and development of the Swordfish Autonomous Surface Vehicle (ASV) system. The work focuses the sensors, actuators, communications and C4I of an unmanned vehicle for marine operations. SWORDFISH is an autonomous surface vehicle used as the central communications link between air, undersea, and terrestrial robotic vehicles of a network centric operation. It is used as a test bed platform for deployment and testing of advanced control and operational concepts for multi-vehicles systems. This new unmanned marine vehicle was done in the context of the PISCIS project. The PISCIS project concerns the development, test and evaluation of new vehicles and new concepts of operation for networked vehicle systems in oceanographic data collection. The PISCIS system includes two autonomous underwater vehicles, the Swordfish ASV, an acoustic navigation system, acoustic and radio communications and a distributed command and control system

ISePorto Robotic Soccer Team: A New Player Generation

Proceedings of the Scientific Meeting of the Portuguese Robotics Open 2004This paper describes the recent modifications in ISePorto MSL robotic football team and future improvements concerning the development and evolution of the team. The robot was substantially redesigned in order to achieve high reliability, allow better control and coordination capabilities and substantial increase in perception. New mechanical and hardware redesign is presented. Motion control subsystems, new vision hardware sensor and overall architecture are described. The team redesign is done for preparation for participating in the Robocup 2004. The main goal is to achieve not only an important evolution in the team control and coordination but also increased overall reliability

Neutral heavy lepton production at next high energy e+e−e^+e^- linear colliders

The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process $e^+e^- \longrightarrow {\nu} e^{\pm} W^{\mp}$ is calculated including on-shell and off-shell heavy neutrino effects. We present a detailed study of cross sections and distributions that shows a clear separation between the signal and standard model contributions, even after including hadronization effects.Comment: 4 pages including 15 figures, 1 table. RevTex. Accepted in Physical Review

Biovalorization of technical lignins for added-value products and applications

Lignin is an abundant non-toxic amorphous natural polymer. Nowadays it is available a great variety and large amounts of technical lignins as by-products from the pulp and paper industries. Some successful biotechnological applications of enzymatically modified lignins are described in the literature, namely for the production of lignin based copolymers, binders for wood composites, chelating agents, compositions for treating porous materials, coatings, paintings and others. From a new species from Bjerkandera genus which exhibits high decolourisation activity on Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated, purified and identified the main enzyme responsible for Remazol Brilliant Blue R dye decolourisation. Such an enzyme is able to oxidise manganese, as well as VA and DMP in manganese-independent reactions; the enzyme substrate range for oxidation of several phenolic and non-phenolic aromatic compounds was determined. This enzyme was tested for transformation of a lignin fraction obtained from straw pulping. Characterisation by gel filtration chromatography of the evolution of the molecular mass distribution of the lignin fragments generated by said enzyme indicated that this enzyme is able to interact directly with lignin in the absence of other mediators

A co-cretion process for premium traditional portuguese pocket knifes

During an eight weeks DEMOLA project, from March to June 2019, a team of five students together with the representative of Martins Cutelaria Tradicional de Palaçoulo, putted into practice the steps towards an innovative design of a new premium series, the “Portuguese History Collection”. This design project was driven through a co-creation process with the traditional Portuguese pocket knifes company Martins Cutelaria Tradicional de Palaçoulo, based in the old village of Palaçoulo, Bragança, Portugal (see [1]). Martins Cutelaria, which has a long history in the design, production and innovation of traditional Portuguese pocket knifes, launched the challenge of designing a new premium line for their traditional pocket knifes segment. The challenge was to innovate while keeping untouched the identity, tradition and the solid values that are the pillars of the company since it was founded in 1954. Based on the company's motto: “Ter uma navalha Martins Palaçoulo, é ter nas mãos um pedaço da nossa história."(*) and inspired by the fact that the year 2019 celebrates the 500th anniversary of the departure of the navigator Fernão de Magalhães for his circumnavigation of the globe by sea, the team worked out the new pocket knifes collection “Portuguese History Collection – The Navigations”.info:eu-repo/semantics/publishedVersio