Theoretical models for rates of heterogeneous reactions during combustion and gasification of liquid fuels in fluidized beds

Two mathematical models to allow computations of chemical species production or consumption rates by heterogeneous reactions taking place during combustion and gasification of liquid fuels sprayed on or injected into fluidized beds of solid particles are proposed. The possibilities envisaged here are called: the CIP (Coated Inert Particles) and the CSP (Coke Shell Particle) models. The former assumes that the injected liquid fuel immediately coats the fluidized inert particles in the bed and then goes through pyrolysis, combustion and gasification reactions. The latter presumes that the liquid fuel drops go through fast pyrolysis before meeting any inert particles and the remaining coke hollow particles react with gases in the bed. Analytical solutions for various geometries of the inert particles in the bed are presented. The work does not include the governing equations which constitute the whole mathematical model of fluidized-bed reactors. Such can be found elsewhere. The present work concentrates only on the theoretical aspects. Experimental tests would allow verification if they properly represent the processes of liquid consumption during combustion and gasification processes consuming liquid fuels in fluidized beds and which model would better fit each individual situation5811412

COVID 19 E A CRISE DE PERFORMANCE CONTRATUAL NOS CONTRATOS INTERNACIONAIS REGIDOS PELA CONVENÇÃO DE VIENA SOBRE CONTRATOS DE COMPRA E VENDA INTERNACIONAL DE MERCADORIAS (CISG)

Objetivos: Através deste artigo analisaremos as implicações da pandemia do vírus COVID-19 nos contratos internacionais, impactando as cláusulas de performance segundo a CISG.Metodologia: A pesquisa foi realizada mediante uma abordagem indutiva, hipotética, entendimento de conceitos jurídicos e uma pesquisa bibliográfica/documental, com objetivo exploratório e conclusivo.Resultados: O estudo do assunto nos leva à algumas conclusões quanto ao não cumprimento total ou parcialmente dos contratos internacionais do comércio em razão das dificuldades impostas pela crise epidemiológica mundial da COVID-19.Contribuições: Trata-se de assunto de grande relevância e atual, em especial pelos impactos que estão acarretando nas economias dos diversos Países e na sociedade como um todo, se inserindo num estudo de interesse do Direito Internacional.Palavras-chave: COVID-19; Riscos nos Contratos Internacionais; CISG; Hardship.  ABSTRACTObjectives: This paper analyzes the implications of the COVID-19 pandemic in international commercial contracts and its impacts on the obligations performance within the United Nations Convention on Contracts for the International Sale of Goods (CISG).Methodology: The research was conducted through an inductive, hypothetical approach, based on an understanding of legal concepts and a bibliographic/documentary survey, with an exploratory and conclusive objective.Results: The study leads to some conclusions regarding the total or partial failure to perform contracts due to the COVID-19 pandemic and its consequences on international trades.Contributions: This is a topical matter of great relevance, given its impacts on the different countries’ economies and on the society as a whole, which falls within the field of interest of international law.Keywords: COVID-19; Risks in International Contracts; CISG; Hardships.

EGFC: Evolving Gaussian Fuzzy Classifier from Never-Ending Semi-Supervised Data Streams -- With Application to Power Quality Disturbance Detection and Classification

Power-quality disturbances lead to several drawbacks such as limitation of the production capacity, increased line and equipment currents, and consequent ohmic losses; higher operating temperatures, premature faults, reduction of life expectancy of machines, malfunction of equipment, and unplanned outages. Real-time detection and classification of disturbances are deemed essential to industry standards. We propose an Evolving Gaussian Fuzzy Classification (EGFC) framework for semi-supervised disturbance detection and classification combined with a hybrid Hodrick-Prescott and Discrete-Fourier-Transform attribute-extraction method applied over a landmark window of voltage waveforms. Disturbances such as spikes, notching, harmonics, and oscillatory transient are considered. Different from other monitoring systems, which require offline training of models based on a limited amount of data and occurrences, the proposed online data-stream-based EGFC method is able to learn disturbance patterns autonomously from never-ending data streams by adapting the parameters and structure of a fuzzy rule base on the fly. Moreover, the fuzzy model obtained is linguistically interpretable, which improves model acceptability. We show encouraging classification results.Comment: 10 pages, 6 figures, 1 table, IEEE International Conference on Fuzzy Systems (FUZZ-IEEE 2020

Competition and supplier loyalty: lessons from the Brazilian tobacco industry

This paper aims to identify both the level and the reasons of the decreasing loyalty in the transactions between tobacco growers and tobacco processors in Brazil. The theoretical approach relies on Transaction Cost Economics. Semi-structured interviews we10343401341

Modelling and Coordination of Building design:an experience of BIM learning/upskilling

The implementation of Building Information Modelling (BIM) in the Architecture, Engineering, Construction and Operations (AECO) industry requires multidisciplinary teams equipped with new technical and managerial skills. Professionals that are inexperienced or unfamiliar with the BIM design process face difficulties in transposing complex concepts into BIM modelling and coordination practices, despite governments, industry bodies, and academia's efforts. With this issue in mind, this article's objective is to present the teaching-learning strategies and tools adopted in a practical case of modelling an existing building on a BIM platform. In terms of method, a phenomenological approach has been taken to report on an exploratory didactic experience. The Cognitive Load Theory (CLT) was used to assess learning based on the authors’ perceptions. The research has been structured into the following five stages: Literature Review; Analysis of Brazilian and International BIM Standards and Guides; Didactic exercise; Experience Assessment; and Conclusions. The results reveal aspects of BIM processes that can be widely investigated in an academic environment, such as the BIM design and coordination process model, which can be explored as a tool in the BIM teaching-learning process. Also, difficulties related to teaching BIM management processes were identified, thus calling for different didactic approaches. The contributions made by the research come from reporting and analysing the process of learning complex BIM content from the perspective of inexperienced professionals. The work also contributes to the field through the BIM learning assessment proposal and the BIM process model resulted from the authors’ practical experience.</p