Linear Pinch Equilibrium of Non-Neutral Plasma Revisited: Phenomenological Consequences of a Numerical Accuracy Problem

Weibel in 1959 under considerations of a collisionless non-neutral cylindrical plasma column studied a linear pinch confinement equilibrium. As reported here, due to non-linearity of the ordinary differential equations obtained for the electrostatic and magnetostatic fields is possible to demonstrate that the confining features previously obtained are extremely dependent on the initial conditions, and the arrangement of two parameters (β - the ratio between ion and electron mass; M/KT - ratio between relativistic rest energy associated with the pair electron-ion and thermal energy kT ) related to the plasma column characteristics. We investigated in this paper the plasma column behavior (confining or non-confining) under modifications of that set of parameters. We detected a set of parameters values that imposes a confining configuration with an electronic skin effect on the plasma column, not yet reported or discussed in the literature

A multicriteria evaluation system for large real estate investments

As an economic engine of contemporary societies, the real estate market needs to be carefully analyzed in terms of both urban management and private or public investment. Information on this market’s behavior can facilitate the identification of turning points in societies’ economic history. Analysts should focus not only on conditioning variables and other important determinants of relevance to investment evaluations but also on the impacts of each variable or factor. Measuring these effects is a key activity in decision-making processes. Given real estate’s growing importance to sustainable economic growth, this study concentrates on creating a multicriteria model for evaluating large real estate investments. A constructivist, process-oriented approach was applied in group work sessions held with a panel of experts with experience in dealing with this issue. These specialists structured the problem of evaluating large real estate investments using value-focused thinking (VFT) and cognitive mapping. The best-worst method (BWM) was then applied to calculate trade-offs among decision criteria and calibrate the evaluation system. The results were presented to and validated by a representative of Instituto da Habitação e da Reabilitação Urbana (Institute for Housing and Urban Rehabilitation), who identified the advantages and limitations of the proposed model, and suggested possible improvements.info:eu-repo/semantics/publishedVersio

Effect of superior blepharoplasty on tear film: objective evaluation with the Keratograph 5M - a pilot study

PURPOSE: To evaluate the effect of superior blepharoplasty on the tear film using the corneal topographer Keratograph 5M. METHODS: A prospective study was performed of 27 eyes of 14 patients with superior dermatochalasis who underwent superior blepharoplasty between May and June 2016. Conservative upper eyelid blepharoplasty was performed by an en bloc resection of anterior lamellar tissue that included skin, subcutaneous tissue, and the orbicularis oculi muscle. All the eyes were imaged using the noninvasive tear breakup time tools of the Keratograph 5M. The following parameters were recorded in each patient before and 6 weeks after surgery: first noninvasive Keratograph 5M tear breakup time (the time at which the first breakup of tears occurs) and average noninvasive Keratograph 5M tear breakup time (the average time of all breakup incidents). The exclusion criteria were ophthalmological pathology, previous eyelid surgery, use of eye drops, systemic pathology, and medication that interferes with lacrimal tears. RESULTS: The mean age of the patients was 65.1 years (range, 51-84); 86% were female. Student's t-test was used to compare the values of first and average noninvasive Keratograph 5M tear breakup times before and after surgery. The values for first noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were not significantly different (9.04 and 8.71, respectively; p=0.926). The values for average noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were also not significantly different (13.01 seconds and 13.14 seconds, respectively; p=0.835). CONCLUSIONS: The results of this pilot study suggest that upper blepharoplasty does not affect tear breakup time according to the objective evaluation of breakup time with the Keratograph 5M.info:eu-repo/semantics/publishedVersio

Investigação das argamassas antigas de revestimento da Redução Jesuítica Guarani, São Miguel Arcanjo, Brasil

A Redução Guaranítica de São Miguel Arcanjo, um dos sete povos missioneiros que se instalaram no noroeste do estado do Rio Grande do Sul, Brasil, por volta de 1687 no atual sítio, e parte de um dos trinta povos formados pela Companhia de Jesus. Dada a sua relevância histórica para o Brasil, este estudo tem como objetivo principal caracterizar analiticamente a constituição físicoquímica das argamassas originais, que ainda pontualmente são encontradas na Ruína, identificar seus principais materiais constituintes, bem como a existência ou não da cal e a forma com que esta se apresenta. Resultados obtidos, por microscopia eletrônica de varredura (MEV-EDS), difração de raios X (DRX), espectroscopia no infravermelho por transformada de Fourier (FTIR), análise granulométrica e análise por termogravimétrica (TG/DTG) indicam que a fonte principal de aglomerante era a cal. Cal, de origem animal ou pétrea, com a presença da cal calcítica em ambos os conjuntos de amostras. Os estudos mostram a presença da variação do carbonato de cálcio em aragonita nas amostras internas e de hidroxiapatita nas externas. Assim, com base neste estudo, busca-se de modo simplificado facilitar o trabalho de investigação de uma obra de restauro, com a criação de uma rotina básica para conhecimento e caracterização da matéria a ser restaurada se necessário para posterior intervenção

Evaluation of exact electro-elastic static and free vibration solutions of multilayered plates for benchmarking: Piezoelectric composite laminates and soft core sandwich plates

Abstract This work provides a study on three-dimensional exact electro-elastic static and free vibration solutions of multilayered plates, focused on a comprehensive evaluation of well-known benchmarks for piezoelectric and/or composite laminates as well as soft core sandwich plates, adding much to thus far available in the literature. The exact solution method for simply supported multilayered plates is fully described in line with earlier leading works, compiled in a single study in a consistent form throughout. The layers involved can be either piezoelectric layers poled through-thickness (i.e. extension mode) or purely elastic layers, including composite layers. For each layer, the form of the through-thickness exact solution depends strongly on its material properties, thus each case arising from an orthotropic, transversely isotropic or simply isotropic layer is considered specifically. Within the free vibration solution, in agreement with an in-plane mode (nx, ny), the so-called special modes for either n x = 0 or n y = 0 , though often overlooked, are purposely addressed, along with thickness modes for each pair (nx, ny). The benchmarks cover purely elastic solutions, as in composite laminates and soft core sandwich plates, as well as electro-elastic solutions, namely piezoelectric composite laminates, involving not only but especially thick plates. For each multilayered plate, the static solution considers either an applied load or an applied electric potential, providing a detailed through-thickness evaluation of displacements and stresses, and when present, the electric potential and electric displacements. The respective free vibration solution reveals the first twenty natural frequencies and associated modes, including all together special modes and thickness modes

Procedure for Sr and Nd isotope analysis in the terrigenous component of marine sediments

Neste trabalho, apresenta-se um protocolo analítico para a obtenção das razões isotópicas 87Sr/86Sr e 143Nd/144Nd na fracção detrítica de sedimentos marinhos. Dado ser comum estes materiais apresentarem uma fracção biogénica carbonatada significativa, foram testadas diversas metodologias com o objectivo de extrair selectivamente os carbonatos sem comprometer a composição da componente terrígena. O ataque com ácido acético 5N durante 12h, à temperatura ambiente, revelou ser eficaz na remoção dos carbonatos e, simultaneamente, preservar fases detríticas que incorporam concentrações significativas de lantanídeos. A aplicabilidade do protocolo desenvolvido é ilustrado com a análise isotópica de amostras de um core colhido no talude continental da Galiza. Os resultados obtidos, em ambos os sistemas de decaimento radioactivo, para além de serem consistentes com a assinatura isotópica de materiais resultantes da erosão de crosta continental, também permitem detectar, através do decréscimo dos valores de εNd em determinados níveis do core, alguns episódios (eventos de Heinrich) em que a fonte crustal terá sido bastante diferente da habitual.In this paper, an experimental procedure for measuring 87Sr/86Sr and 143Nd/144Nd ratios in the detrital fraction of marine sediments is presented. Since these sediments commonly include a significant biogenic carbonate fraction, several methodologies were tested in order to leach the carbonates without compromising the composition of the terrigenous component. The extraction with 5N acetic acid for 12 hours, at room temperature, reveals (a) to be effective in the removal of carbonates, and (b) to preserve detrital phases that incorporate important amounts of REE. The applicability of this chemical procedure is illustrated with analyses done on samples from a core collected in the Galician continental slope. The results for both radiogenic decay systems, on one hand, are consistent with the isotope signature of material resulting from the erosion of continental crust and, one the other hand, allow the identification of several episodes of modification of the source areas involved