Tensor interactions and τ\tau decays

We study the effects of charged tensor weak currents on the strangeness-changing decays of the $\tau$ lepton. First, we use the available information on the $K^+_{e3}$ form factors to obtain BR$(\tau^- \rightarrow K^-\pi^0 \nu_{\tau})\sim {\cal O}(10^{-4})$ when the $K\pi$ system is produced in an antisymmetric tensor configuration. Then, we propose a mechanism for the direct production of the $K_2^*(1430)$ in $\tau$ decays. Using the current upper limit on this decay we set a bound on the symmetric tensor interactions.Comment: 13 pages, Late

Non-Gaussian numerical errors versus mass hierarchy

We probe the numerical errors made in renormalization group calculations by varying slightly the rescaling factor of the fields and rescaling back in order to get the same (if there were no round-off errors) zero momentum 2-point function (magnetic susceptibility). The actual calculations were performed with Dyson's hierarchical model and a simplified version of it. We compare the distributions of numerical values obtained from a large sample of rescaling factors with the (Gaussian by design) distribution of a random number generator and find significant departures from the Gaussian behavior. In addition, the average value differ (robustly) from the exact answer by a quantity which is of the same order as the standard deviation. We provide a simple model in which the errors made at shorter distance have a larger weight than those made at larger distance. This model explains in part the non-Gaussian features and why the central-limit theorem does not apply.Comment: 26 pages, 7 figures, uses Revte

High-Accuracy Calculations of the Critical Exponents of Dyson's Hierarchical Model

We calculate the critical exponent gamma of Dyson's hierarchical model by direct fits of the zero momentum two-point function, calculated with an Ising and a Landau-Ginzburg measure, and by linearization about the Koch-Wittwer fixed point. We find gamma= 1.299140730159 plus or minus 10^(-12). We extract three types of subleading corrections (in other words, a parametrization of the way the two-point function depends on the cutoff) from the fits and check the value of the first subleading exponent from the linearized procedure. We suggest that all the non-universal quantities entering the subleading corrections can be calculated systematically from the non-linear contributions about the fixed point and that this procedure would provide an alternative way to introduce the bare parameters in a field theory model.Comment: 15 pages, 9 figures, uses revte

T-violation in Kμ3K_{\mu3} decay in a general two-Higgs doublet model

We calculate the transverse muon polarization in the $K^+_{\mu3}$ process arising from the Yukawa couplings of charged Higgs boson in a general two-Higgs doublet model where spontaneous violation of CP is presentComment: 6 pages, latex, accepted for publication in Phys. Rev.

Industrial applications of power electronics

Electronic applications use a wide variety of materials, knowledge, and devices, which pave the road to creative design, development, and the creation of countless electronic circuits with the purpose of incorporating them in electronic products. Therefore, power electronics have been fully introduced in industry, in applications such as power supplies, converters, inverters, battery chargers, temperature control, variable speed motors, by studying the effects and the adaptation of electronic power systems to industrial processes. Recently, the role of power electronics has been gaining special significance regarding energy conservation and environmental control. The reality is that the demand for electrical energy grows in a directly proportional manner with the improvement in quality of life. Consequently, the design, development, and optimization of power electronics and controller devices are essential to face forthcoming challenges. In this Special Issue, 19 selected and peer-reviewed papers discussing a wide range of topics contribute to addressing a wide variety of themes, such as motor drives, AC-DC and DC-DC converters, electromagnetic compatibility and multilevel converters.publishersversionpublishe

A review of data mining applications in semiconductor manufacturing

The authors acknowledge Fundacao para a Ciencia e a Tecnologia (FCT-MCTES) for its financial support via the project UIDB/00667/2020 (UNIDEMI).For decades, industrial companies have been collecting and storing high amounts of data with the aim of better controlling and managing their processes. However, this vast amount of information and hidden knowledge implicit in all of this data could be utilized more efficiently. With the help of data mining techniques unknown relationships can be systematically discovered. The production of semiconductors is a highly complex process, which entails several subprocesses that employ a diverse array of equipment. The size of the semiconductors signifies a high number of units can be produced, which require huge amounts of data in order to be able to control and improve the semiconductor manufacturing process. Therefore, in this paper a structured review is made through a sample of 137 papers of the published articles in the scientific community regarding data mining applications in semiconductor manufacturing. A detailed bibliometric analysis is also made. All data mining applications are classified in function of the application area. The results are then analyzed and conclusions are drawn.publishersversionpublishe

Environmental and economic assessment of a steel wall fabricated by wire-based directed energy deposition

Funding Information: The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT-MCTES) for its financial support via the project UIDB/00667/2020 (UNIDEMI). JPO acknowledges funding by national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020 , UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. The authors wish to thank Mr. Igor Felice and Mr. Antonio Campos for their help in conducting WAAM process. This activity has received funding from the European Institute of Innovation and Technology (EIT) – Project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. This body of the European Union receives support from the European Union's Horizon 2020 research and innovation programme. Publisher Copyright: © 2022 The AuthorsOver the past few decades, adoption of different Additive Manufacturing (AM) processes has gained momentum in the manufacturing industry. One such emerging AM process is wire-based directed energy deposition. Environmental impacts and costs are important criteria for adoption of any manufacturing process. Therefore, the aim of this paper is to evaluate the environmental and economic performance of Wire and Arc Additive Manufacturing (WAAM) using Life Cycle assessment (LCA) and Life Cycle Costing (LCC) methodologies. In this paper, an integrated methodology to conduct a cradle-to-gate LCA based on the guidelines of ISO 14044 and LCC based on IEC 60300–3–3 standards is proposed. A case study of a single steel wall manufactured by WAAM was analysed. The environmental impacts and production costs for wire-based directed energy deposition process were compared to laser powder bed fusion (LPBF) and Computer Numeric Control (CNC) milling processes. For the steel wall analysed, CNC milling was the most economical and ecological option followed by the wire-based directed energy deposition and LPBF. However, the performance of a process depends on product complexity and the manufacturing process's material efficiency. Raw material production and labour were identified as major environmental hotspot and cost driver, respectively, in wire-based directed energy deposition. The methodology used in this paper can be extended to other manufacturing processes.publishersversionpublishe

A comprehensive review of industrial symbiosis

Industrial symbiosis, which allows entities and companies that traditionally be separated, to cooperate among them in the sharing of resources, contributes to the increase of sustainability with environmental, economic and social benefits. Examples of industrial symbiosis have grown over the years with increasing geographic dispersion. Thus, through a comprehensive review of previous studies, this work aims to trace the trend of industrial symbiosis research and to map the existing case studies around the world, with a critical analysis of its impact. The analysis of the 584 selected publications allowed tracing the evolution of these according to their content and the type of article, as well as its distribution by journals. Based on the literature review, the main lines for research in industrial symbiosis are assessed, as well as an updated study of the published case studies is provided with emphasis on the location, type of industry and employed methodologies. Several challenges are then identified for future research. The results reveal the number of articles on industrial symbiosis has greatly increased since 2007 and China is the country with the largest number of publications and cases of industrial symbiosis, followed by the United States. The methods for quantifying impacts and analysing industrial symbiosis networks were the most widely used. The analysis of the published case studies allowed an overview of the industrial symbiosis in the world and showed that the potential for application is enormous, both in developed countries and in countries with developing economies, and although the most present economic activities in the synergies are associated with the manufacturing sector, the possibilities of industrial symbiosis are not restricted to these activities nor to the number of entities involved. The symbioses between industry and the surrounding community also have great potential for development with numerous advantages for both parties.publishe

Current status, emerging challenges, and future prospects of industrial symbiosis in Portugal

Radu Godina would like to acknowledge financial support from Fundacao para a Ciencia e Tecnologia (UID/EMS/00667/2019).Industrial symbiosis has proven to be an important tool for improving business sustainability with numerous environmental, economic, and social benefits. The literature on this subject has been provided with countless case studies of the application of this practice in different geographical locations. However, studies concerning Portugal in this area are still scarce. Thus, this article aims to map and analyze the existing cases of industrial symbiosis in Portugal, as well as the current state and the legislative context regarding this practice. It also aims to analyze the main barriers to the growth of synergy relations and outline new paths for the development of industrial symbiosis in Portugal. From the analysis to the case studies, it was possible to conclude that most industrial symbiosis networks have few actors, and networks with two and three are common. However, owing to strategic plans, the type of existing economic activities, and the waste generated, there is much potential for industrial symbiosis networks to be established and to contribute to emission reductions, more efficient use of resources, and reduced external dependence. However, in order to increase industrial symbiosis, concerted action must be taken at various levels to encourage companies to develop synergy relations. Changing the legislative framework, making funds available, the role of local governments, the existence of a facilitator, and the use of some industries as anchor tenants are some of the aspects that can contribute to the increase of industrial symbiosis in Portugal.publishersversionpublishe