Symmetries and conservation laws in the Gunther k-symplectic formalism of field theory

This paper is devoted to studying symmetries of k-symplectic Hamiltonian and Lagrangian first-order classical field theories. In particular, we define symmetries and Cartan symmetries and study the problem of associating conservation laws to these symmetries, stating and proving Noether's theorem in different situations for the Hamiltonian and Lagrangian cases. We also characterize equivalent Lagrangians, which lead to an introduction of Lagrangian gauge symmetries, as well as analyzing their relation with Cartan symmetries.Comment: 29 page

Nonholonomic constraints in kk-symplectic Classical Field Theories

A $k$-symplectic framework for classical field theories subject to nonholonomic constraints is presented. If the constrained problem is regular one can construct a projection operator such that the solutions of the constrained problem are obtained by projecting the solutions of the free problem. Symmetries for the nonholonomic system are introduced and we show that for every such symmetry, there exist a nonholonomic momentum equation. The proposed formalism permits to introduce in a simple way many tools of nonholonomic mechanics to nonholonomic field theories.Comment: 27 page

Accuracy Evaluation of Ultrasound Probe Sonication and Microwave-Assisted Extraction Systems for Rapid Single Extraction of Metals in Soils

The accumulation of metals in soils and sediments causes a potential risk to human health due to the transfer of these elements to other environmental compartments. However, metals are present in soils under different chemical forms or types of binding, so the total metal content is a poor indicator of their bioavailability, mobility or toxicity, since these properties basically depend on the chemical association of the different soil components. Therefore, the environmental impact of metalliferous soils is better assessed on the basis of the environmental accessibility of metals, i.e. the bioavailable forms for plants. In the present work, ultrasonic probe sonication (UPS) and microwave-assisted extraction (MAE) have been evaluated as alternatives to the conventional Standards, Measurements and Testing program (SM&T) procedures for single extraction of metals in soils, in order to reduce the extraction time and the consumption of samples and extracting agents. Optimization studies were carried out on the certified reference materials (CRMs) BCR 483 (Sewage sludge amended soil) and BCR 700 (Organic rich soil) for accuracy evaluation of the proposed methods. Extractable concentrations of Cd, Cr, Cu, Ni and Zn using 0.01 M calcium chloride (in BCR 483), and also of Pb with 0.43 M acetic acid and 0.05 M ethylenediaminetetraacetic acid at pH 7.0 (in both CRMs) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES)

Fast Mode Decision on H.264/AVC Baseline Profile for real-time performance

In this paper a new fast mode decision (FMD) algorithm is proposed for the recent H.264/AVC video coding standard, aiming to reduce its computational load without loosing coding efficiency. This algorithm identifies redundancy and selects the minimum sub-set of modes for each macroblock (MB) required to provide high rate-distortion (RD) efficiency. It is based on a fast analysis of the histogram of the difference image between frames which classifies the areas of each frame as active or non-active by means of an adaptive thresholding technique. More coding effort is devoted to active areas with the selection of a large sub-set of Modes, as these areas are expected to be the most relevant in terms of RD cost. Results show reduction values around 35–65% of motion estimation (ME) time, preserving the RD cost for the Baseline Profile, by using P-Slices and without needing B-Slices. Moreover, the strategy works as an intelligent tool for real-time applications with constrained number of operations per frame: it wisely uses the given operational resources distributing them among those MBs that need it

Photoelectric Properties of MOS-like Structures with Twofold SRO Films

AbstractThe optical properties of silicon rich oxide (SRO) have been deeply studied because, between other reasons, they emit an intense photoluminescence (PL) from visible to the near infrared range when excited with UV light. MOS-like structures with SRO film as the active layer have shown an enhanced conductivity under different illumination conditions. In this paper, MOS-like structures with double SRO layer were fabricated in order to have a barrier to isolate the silicon substrate from the active SRO layer. Results show that all structures have a higher current when light shines on them than that obtained under dark conditions. A possible application of this photo-effect can be used to increase the response of photodetectors and silicon solar cells

Industry 4.0-based dynamic Social Organizational Life Cycle Assessment to target the social circular economy in manufacturing

Nowadays in manufacturing, the topic of sustainability plays a key role. However, over the years, economic crises and the climate change debate have focused the attention of scholars, industrialists and policy makers mainly on environmental sustainability, putting social sustainability on the back burner. This is also evident in the scientific literature which highlights several knowledge gaps. The digital transition of factories and Industry 4.0 technologies have not yet been fully exploited to correlate production and social metrics. As a result, there is a lack of adequate tools for monitoring social performance in the factory environment. In this context, the social dimension of the circular economy is still an under-researched topic. This study aims to fill these gaps by integrating Social Organizational Life Cycle Assessment (SO-LCA) and Industry 4.0 technologies in a blended methodological approach designed to dynamically monitor the social performance of a major manufacturing industry. Using primary data, a set of site-specific social indicators and indexes were created to assess the organization's social impact against key stakeholder categories and subcategories. Finally, within that set, those social metrics that the organization considers essential to moving toward the circular economy were identified. Therefore, this study, has contributed to fill the literature gaps by demonstrating that the digitization of production processes, not only enables the assessment of environmental impact, but can also play a key role in knowing the social performance of a manufacturing organization and to identify the hidden social dimension in the circular economy

Evaluation of inflammatory cytokine secretion by human alveolar macrophages.

The alveolar macrophage (AM) secretes interleukin 1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8), all of them inflammatory cytokines involved in the pathogenesis of many lung diseases. The aim of the present work was to evaluate the basal and stimulated secretion of these cytokines by human AMs. Human AMs were collected by bronchoalveolar lavage (BAL) from four healthy controls and 13 patients with diffuse interstitial lung disease (five cases of sarcoidosis, three of hypersensitivity pneumonitis and five of idiopathic pulmonary fibrosis). AMs were cultured in the presence or absence of different concentrations of lipopolysaccharide (LPS), phorbolmyristate and gamma-interferon. IL-1beta, TNF-alpha, IL-6 and IL-8 levels were measured in BAL fluid and culture supernatant using specific enzyme-linked immunosorbent assays. The substance found to stimulate the secretion of inflammatory cytokines to the greatest extent was LPS at a concentration of 10 microg/ml. Regarding the secretion of IL-1beta, four observations were of interest: basal secretion was very low; LPS exerted a potent stimulatory effect; considerable within-group variability was observed; and there were no significant differences in the comparisons among groups. With respect to TNF-alpha secretion, the results were similar. The only striking finding was the higher basal secretion of this cytokine with respect to that of IL-1beta. Regarding the secretion of IL-6, the same pattern followed by TNF-alpha was found. However, it should be stressed that the increase induced by LPS was smaller than in the two previous cytokines. Regarding the secretion of IL-8, three findings were patent: the strong basal secretion of this cytokine; the moderate increase induced by LPS; and the existence of significant differences among the different groups with respect to the stimulated secretion of this cytokine, which reached maximum values in patients with idiopathic pulmonary fibrosis. Finally, it should be noted that the pattern of cytokines observed in the BAL fluid was similar to that found in cultured AM supernatants. The pattern of inflammatory cytokine secretion by AMs differs from that of other cells of the mononuclear phagocyte system (MPS). In this sense. AMs secrete low amounts of IL-1, moderate amounts of TNF-alpha and IL-6, and high quantities of IL-8. Adherence is an important stimulus in the secretion of these molecules and LPS elicits an increased secretion inverse to the basal secretion. There is considerable individual variability in the secretion of inflammatory cytokines by the AMs of patients with interstitial lung disease and the AMs of these patients are primed in vivo for the secretion of these cytokines. The results of our study, carried out in vitro, can be extrapolated to the in vivo setting