Inversion of spinning sound fields

A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph

Enhancing elderly mobility through IoT using textiles: a review

The aging of population worldwide and the increasing of average life expectancy of the world population become a social and economic problem for society. It's necessary to provide solutions which can maintain the independency of elderly and their mobility, along more time, avoiding the unnecessary perma-nence in hospitals and institutions for the elderly. The use of IoT using textiles is a very interesting approach because of the proximity of people to these materials. This work reviews the development on IoT using textiles to increase the mobility of elderly people and concludes that this is a field of growing interest. Although, there is few investigation, especially in what concerns studies focusing on the im-portance of improving the mobility of the elderly. There are studies that lead to the possibility of promoting this physical capability but have not been designed for that purpose, but we believe that approach of the problem of mobility of elderly people using the IoT based on clothes should be treated with specificity, because the consequences of this not happening, will affect not only the elderly but the whole society.info:eu-repo/semantics/publishedVersio

Internet of things for the hotel industry: a review

The Internet of Things (IoT) represents an opportunity for the hotel in-dustry to increase customer satisfaction while simultaneously reducing operational costs. This paper analyses the existing knowledge on this subject, through a re-view of the relevant publications indexed by Scopus and/or ISI Web of Science, concluding that, despite the existence of many relevant patents, registered in the past few years, the published research is very limited on this topic. The restriction to publication prior to the conclusion of the patent registration process may be a justification for this fact, and, if so, the near future will bring many novelties that will help the development of the hotel industry. It is also possible to conclude from this work that the potential of IoT is not yet well explored in the hotel indus-Try, once authors frequently theorize on the use of IoT for applications that could easily be of interest for the hotel industry, but fail to identify that opportunity as a major market.info:eu-repo/semantics/publishedVersio

Spin-glass phase transition and behavior of nonlinear susceptibility in the Sherrington-Kirkpatrick model with random fields

The behavior of the nonlinear susceptibility $\chi_3$ and its relation to the spin-glass transition temperature $T_f$, in the presence of random fields, are investigated. To accomplish this task, the Sherrington-Kirkpatrick model is studied through the replica formalism, within a one-step replica-symmetry-breaking procedure. In addition, the dependence of the Almeida-Thouless eigenvalue $\lambda_{\rm AT}$ (replicon) on the random fields is analyzed. Particularly, in absence of random fields, the temperature $T_f$ can be traced by a divergence in the spin-glass susceptibility $\chi_{\rm SG}$, which presents a term inversely proportional to the replicon $\lambda_{\rm AT}$. As a result of a relation between $\chi_{\rm SG}$ and $\chi_3$, the latter also presents a divergence at $T_f$, which comes as a direct consequence of $\lambda_{\rm AT}=0$ at $T_f$. However, our results show that, in the presence of random fields, $\chi_3$ presents a rounded maximum at a temperature $T^{*}$, which does not coincide with the spin-glass transition temperature $T_f$ (i.e., $T^* > T_f$ for a given applied random field). Thus, the maximum value of $\chi_3$ at $T^*$ reflects the effects of the random fields in the paramagnetic phase, instead of the non-trivial ergodicity breaking associated with the spin-glass phase transition. It is also shown that $\chi_3$ still maintains a dependence on the replicon $\lambda_{\rm AT}$, although in a more complicated way, as compared with the case without random fields. These results are discussed in view of recent observations in the LiHo$_x$Y$_{1-x}$F$_4$ compound.Comment: accepted for publication in PR

Quantum critical point in the spin glass-antiferromagnetism competition in Kondo-lattice systems

A theory is proposed to describe the competition among antiferromagnetism (AF), spin glass (SG) and Kondo effect. The model describes two Kondo sublattices with an intrasite Kondo interaction strength $J_{K}$ and an interlattice quantum Ising interaction in the presence of a transverse field $\Gamma$. The interlattice coupling is a random Gaussian distributed variable (with average $-2J_0/N$ and variance $32 J^{2}/N$) while the $\Gamma$ field is introduced as a quantum mechanism to produce spin flipping. The path integral formalism is used to study this fermionic problem where the spin operators are represented by bilinear combinations of Grassmann fields. The disorder is treated within the framework of the replica trick. The free energy and the order parameters of the problem are obtained by using the static ansatz and by choosing both $J_0/J$ and $\Gamma/J \approx (J_k/J)^2$ to allow, as previously, a better comparison with the experimental findings. The results indicate the presence of a SG solution at low $J_K/J$ and for temperature $T<T_{f}$ ($T_{f}$ is the freezing temperature). When $J_K/J$ is increased, a mixed phase AF+SG appears, then an AF solution and finally a Kondo state is obtained for high values of $J_{K}/J$. Moreover, the behaviors of the freezing and Neel temperatures are also affected by the relationship between $J_{K}$ and the transverse field $\Gamma$. The first one presents a slight decrease while the second one decreases towards a Quantum Critical Point (QCP). The obtained phase diagram has the same sequence as the experimental one for $Ce_{2}Au_{1-x}Co_{x}Si_{3}$, if $J_{K}$ is assumed to increase with $x$, and in addition, it also shows a qualitative agreement concerning the behavior of the freezing and the Neel temperatures.Comment: 11 pages, 3 figures, accepted for publication in J. Phys.

Seismic vulnerability of churches in Faial and Pico islands, Azores

Earthquakes represent one of the main cause of serious damage and loss of historic and architectural heritage. Interventions to preserve these building should start with a careful knowledge and assessment of their seismic vulnerability, in order to support any needed retrofitting and strengthening measures. This paper proposes a procedure to register and diagnose of the level of damage on churches after the occurrence of an earthquake, and also to assess the seismic vulnerability of this type of construction. This procedure was applied to sixteen churches in the Azores islands which were hit by the July 9th 1998 earthquake. Belfries of church towers are elements with a particular seismic vulnerability. For this reason, and based on the Italian methodology proposed by the Linee Guida (2006), it is applied to belfries of two churches from Pico (Azores), a simplified mechanical model for assessment of seismic vulnerability of this type of structures

Adolescents’ resilience in residential care: A systematic review of factors related to healthy adaptation

Research with young people in Residential Care (RC) has primarily focused on mental health problems, overlooking resilience and adaptation. Considering that previous trauma experiences and adversity (e.g., previous abuse and neglect) cannot be changed, it is critical to identify the current protective factors of adaptation in RC. Purpose: this systematic review aims to identify the protective factors or the resilience portfolio that may be positively associated with adolescents’ healthy adaptation in RC. Method: based on the PRISMA statement and using a combination of keywords related with RC, adolescents, resilience, and adaptation a search in eight databases was conducted in November 2020: Academic Search Complete, APA PsycArticles, APA PsycINFO, Psychology and Behavioral Sciences Collection, ERIC, MEDLINE, Web of Science and Scopus. This search yielded 4442 articles and 11 studies met our inclusion criteria. Results: Overall, the studies reported protective factors at different levels, namely, individual assets, resources from different contexts (family, RC, and community), appraisals and coping behavior. Conclusion: this review highlighted the importance of exploring resilience as a dynamic process of assets and resources rather than as a stable individual attribute. This review aims to contribute to a deep discussion about resilience in RC, informing policy-making and professional practices and enhancing young people’s adaptation in RC.info:eu-repo/semantics/acceptedVersio

Control of state and state entanglement with a single auxiliary subsystem

We present a strategy to control the evolution of a quantum system. The novel aspect of this protocol is the use of a \emph{single auxiliary subsystem}. Two applications are given, one which allows for state preservation and another which controls the degree of entanglement of a given initial state