Analysis of the Common Ignition Sources in the Milling Industry

In the summer of 2007, in Fossano, Italy, one of the most catastrophic and famous dust explosions in Italy, caused by flour dust, occurred in Molino Cordero, a historic cereal milling and flour storage plant. The explosion happened during the pneumatic unloading operation of a tank truck, previously accidentally overfilled. Five people lost their lives, and the building was partially destroyed by the powerful explosion. The forensic reconstruction and investigation of this accident were carried out years after the explosion. This paper has presented an assessment of the main potential ignition sources that can be expected in a flour mill, taking into account the typical equipment that is normally installed in this process. The target is to provide the employer and the users of flour mill plants with basic information that can be helpful in carrying out the specific explosion risk assessment, necessary for every single process. Possible improvements, which could be implemented to reduce the risk of explosion to a tolerable level, will be highlighted

Technical assistance in social housing for the promotion of healthy habitat

A precariedade das condições de moradia no Brasil tem sérias implicações sobre o habitat saudável. No ano de 2020, o advento da pandemia de Covid-19 acrescentou urgência às discussões acerca da habitação saudável, principalmente nas periferias das cidades; onde se encontram as maiores carências: de habitabilidade, de fornecimento de água, de infraestrutura e saneamento básico. Nesse contexto, a aplicação da Lei 11.888 de 2008, da Assistência Técnica em Habitação de Interesse Social (ATHIS), tem oportunizado o acesso ao trabalho dos profissionais de arquitetura para a população de baixa renda. Além disso, as iniciativas de ATHIS têm buscado a consolidação de projetos de habitação de interesse social que resultem na produção de unidades habitacionais mais saudáveis. O presente artigo apresenta um estudo de caso sobre o processo de desenvolvimento da ATHIS para uma comunidade de 68 famílias da cidade de São Leopoldo, Região Metropolitana de Porto Alegre, estado do Rio Grande do Sul. O objetivo deste estudo é compreender como o processo de ATHIS pôde contribuir para a promoção do habitat saudável naquela comunidade. As técnicas de coleta de dados utilizadas foram: análise de documentos, observação assistemática não-participante e entrevistas semiestruturadas. Os resultados permitiram constatar que: i) a ATHIS envolvendo a população através de processo participativo, apresenta contribuições para a melhoria das condições de habitabilidade das populações envolvidas; ii) a ATHIS pode contribuir para a consolidação de um habitat saudável através da melhoria da qualidade do ambiente urbano e habitacional, destacando-se as condições básicas de saneamento.The precariousness of housing conditions in Brazil has serious implications for healthy habitat. In the year 2020, the advent of the Covid-19 pandemic, added urgency to the discussions about healthy housing, especially on the outskirts of cities; where the greatest needs are found: habitability, water supply, infrastructure and basic sanitation. In this context, the application of Law 11,888 of 2008, of Technical Assistance in Social Housing (ATHIS), has provided opportunities for the work of architecture professionals for the low-income population. In addition, ATHIS initiatives have sought to consolidate social housing projects that result in the production of healthier housing units. This article presents a case study on the ATHIS development process for a community of 68 families in the city of São Leopoldo, Metropolitan Region of Porto Alegre, state of Rio Grande do Sul. The objective of this study was to understand how ATHIS process can contribute to the promotion of healthy habitat for low-income populations. The data collection techniques used were: document analysis, non-participant unsystematic observation and semi-structured interviews. The results showed that: i) ATHIS involving the population through a participatory process, contributes to the improvement of the habitability conditions of the populations involved; ii) ATHIS can contribute to the consolidation of a healthy habitat by improving the quality of the urban and housing environment, with emphasis on basic sanitation conditions

Study of the Electric Spark and Combustion Characteristic Times in a Mike 3 Apparatus

Understanding how dust can ignite and explode in an industrial contest is an important and complex task, and much of the work around this is mainly performed via experimental measurements, in accordance to specific standards. However, those same properties are straightforwardly closely related to the nature of the experimental tests. Among these, the Minimum Ignition Energy (MIE) of a dust cloud, that is usually measured in a MIKE 3 apparatus, can be affected by several factors, as: delay time of the electric spark with respect to the dust-air dispersion formation inside the apparatus, dust concentration, humidity content, dust granulometry, etc. The delay time is one of the worst parameters to adjust, because the fluid-dynamics of the dust-air mixture inside the tube is not easily predictable. Within this work, a study on the characteristic times of all the relevant phenomena occurring within a MIKE 3 apparatus was done by means of slow-motion videos of the tests. Particularly, three different characteristic times were compared referring to a given sample of niacin dust: dust lifting and settling times, effective spark delay time (that is, the time at which the spark is visible) and combustion time (that is, the time at which the flame is visible). According to the results, the effective delay time is almost always quite different with respect to the theoretical one, influencing the effective concentration of dust between the electrodes and, finally, the possibility to have a flame ignition or not within the apparatus. This means that the value of the MIE parameter can be profoundly influenced by the effective delay. Keywords: Process Safety; Dust Explosions; Minimum Ignition Energy; Spark Dela

Predictive Models for the Estimation of the Minimum Ignition Energy of Polydisperse Organic Dusts

The process industry is a sector characterized by the sale of 50 % of its products in the form of powder and in which 80 % of the goods generated are made through a production system that involves the use of a powder. This sector massively employs solid materials and, using operations such as material transport, crushing, screening, sanding, trimming, feeding tanks and bins, storage of granular materials and many other activities, is very often characterized by the collateral emission of dusts. A similar scenario makes the risk of a dust explosion one of the major concerns of the process industry. In this context, to ensure the safety of people and infrastructures, it is crucial to obtain the parameters that characterize the explosiveness of the dust. Actually, these parameters are all determined experimentally, involving large economic costs, technical difficulties, and long dead times. This work focused on the estimation of one of these parameters, the Minimum Ignition Energy (MIE), which is considered to be one of the most important to assess the probability of having a dust explosion. Therefore, starting from the experimental test within a 1.2 L Hartmann tube, two new versions of a mathematical model capable of predicting the MIE for an organic powder were proposed. The models characterize the powder analysed through its particle size distribution and a few chemical-physical characteristics obtained from literature. Six organic powders were selected to validate the model (aspirin, cork, corn starch, sugar d50=135 µm, sugar d50=34 µm and wheat flour), with the intention of comparing the theoretical data obtained with literature experimental ones

Uncovering spatiotemporal patterns of atrophy in progressive supranuclear palsy using unsupervised machine learning

To better understand the pathological and phenotypic heterogeneity of progressive supranuclear palsy and the links between the two, we applied a novel unsupervised machine learning algorithm (Subtype and Stage Inference) to the largest MRI data set to date of people with clinically diagnosed progressive supranuclear palsy (including progressive supranuclear palsy-Richardson and variant progressive supranuclear palsy syndromes). Our cohort is comprised of 426 progressive supranuclear palsy cases, of which 367 had at least one follow-up scan, and 290 controls. Of the progressive supranuclear palsy cases, 357 were clinically diagnosed with progressive supranuclear palsy-Richardson, 52 with a progressive supranuclear palsy-cortical variant (progressive supranuclear palsy-frontal, progressive supranuclear palsy-speech/language, or progressive supranuclear palsy-corticobasal), and 17 with a progressive supranuclear palsy-subcortical variant (progressive supranuclear palsy-parkinsonism or progressive supranuclear palsy-progressive gait freezing). Subtype and Stage Inference was applied to volumetric MRI features extracted from baseline structural (T1-weighted) MRI scans and then used to subtype and stage follow-up scans. The subtypes and stages at follow-up were used to validate the longitudinal consistency of subtype and stage assignments. We further compared the clinical phenotypes of each subtype to gain insight into the relationship between progressive supranuclear palsy pathology, atrophy patterns, and clinical presentation. The data supported two subtypes, each with a distinct progression of atrophy: a 'subcortical' subtype, in which early atrophy was most prominent in the brainstem, ventral diencephalon, superior cerebellar peduncles, and the dentate nucleus, and a 'cortical' subtype, in which there was early atrophy in the frontal lobes and the insula alongside brainstem atrophy. There was a strong association between clinical diagnosis and the Subtype and Stage Inference subtype with 82% of progressive supranuclear palsy-subcortical cases and 81% of progressive supranuclear palsy-Richardson cases assigned to the subcortical subtype and 82% of progressive supranuclear palsy-cortical cases assigned to the cortical subtype. The increasing stage was associated with worsening clinical scores, whilst the 'subcortical' subtype was associated with worse clinical severity scores compared to the 'cortical subtype' (progressive supranuclear palsy rating scale and Unified Parkinson's Disease Rating Scale). Validation experiments showed that subtype assignment was longitudinally stable (95% of scans were assigned to the same subtype at follow-up) and individual staging was longitudinally consistent with 90% remaining at the same stage or progressing to a later stage at follow-up. In summary, we applied Subtype and Stage Inference to structural MRI data and empirically identified two distinct subtypes of spatiotemporal atrophy in progressive supranuclear palsy. These image-based subtypes were differentially enriched for progressive supranuclear palsy clinical syndromes and showed different clinical characteristics. Being able to accurately subtype and stage progressive supranuclear palsy patients at baseline has important implications for screening patients on entry to clinical trials, as well as tracking disease progression

Application of an enhanced version of Recursive Operability Analysis for combustible dusts risk assessment

Organic dust explosions were and are still today a critical issue in the food, pharmaceutical, and fine chemical industry. Materials such as flour, corn starch, sugar and APIs represent a cause of severe accidents. In this framework, we investigated a modified version of Recursive Operability Analysis 12Incidental Sequence Diagrams (ROA\u2013ISD), called ROA Plus 12ISD, specifically tailored to describe industrial processes involving organic combustible dusts. Compared to more classical techniques such as Hazard and Operability (HazOp), ROA 12ISD allows for a direct generation of fault trees, providing a useful tool to connect Qualitative with Quantitative Risk Analysis (QRA). ROA Plus 12ISD is very similar to ROA 12Cause Consequence Diagrams (CCD), which has already proven to be an effective tool to perform both risk assessment on existing plants and reconstructing already occurred accidents, given its logical structure and width of the application fields. In this work, we modified specific parts of the standard ROA 12CCD method: (1) the Failure Mode and Operability Analysis (FMEA) database has been structured in order to retrieve the well-known explosion pentagon (for dusts) and all the instruments, devices, apparatuses and controllers typical of industries which process organic dusts; (2) a new comprehensive list of process variables has been compiled. In this way, it is possible to tailor the information required for the generation of the fault trees concerning top events involving mainly dust explosions and fires. This method has been implemented in order to reconstruct the dynamics of the February 2008 Imperial Sugar refinery plant accident (Port Wentworth, GA, USA). Results demonstrated the applicability of the enhanced method by highlighting the criticalities of the process already showed by a previously detailed reconstruction performed by the Chemical Safety Board

A Mathematical Model for the Prediction of the Kst for Metallic Dusts as a Function of the Particle Size Distribution

For several years, dust explosions have been one of the major causes of industrial accidents, spanning from metalworking to pharmaceuticals sectors. In accordance with the latest Chemical Safety Board (CSB) investigations, three out of four dust explosions in the United States involved metallic dusts (iron, titanium, zirconium and aluminum). Many chemical processes involve metal powders for their exceptional mechanical, optical and catalytic properties, such as the production of plastics, rubber, paints, coatings, inks, pesticides, detergents and even drugs. The severity of a dust explosion can be defined using experimental parameters such as the maximum explosion pressure (pmax), the maximum rate of pressure rise ((dp/dt)max) and the deflagration index (Kst), which are employed to predict the consequences of a dust explosion for a given scenario. Among these parameters, the deflagration index plays a fundamental role, as it is used for the design of deflagration nozzles aimed to protect industrial equipment and silos from internal dust explosions. The purpose of this work is to develop a mathematical model able to predict the Kst value of metal powders as a function of chemical-physical data and the particle size distribution (DD50 was used as global information). The model structure is based on the writing and resolution of the material and energy balance equations on the single dust particle, also estimating the contribution of oxygen diffusion which, in the case of metal powders, greatly depends on both tortuosity and porosity. The results well agreed with experimental data, providing the basis for the development of more detailed models

Assistência técnica em habitação de interesse social para promoção do habitat saudável

The precariousness of housing conditions in Brazil has serious implications for healthy habitat. In the year 2020, the advent of the Covid-19 pandemic, added urgency to the discussions about healthy housing, especially on the outskirts of cities; where the greatest needs are found: habitability, water supply, infrastructure and basic sanitation. In this context, the application of Law 11,888 of 2008, of Technical Assistance in Social Housing (ATHIS), has provided opportunities for the work of architecture professionals for the low-income population. In addition, ATHIS initiatives have sought to consolidate social housing projects that result in the production of healthier housing units. This article presents a case study on the ATHIS development process for a community of 68 families in the city of São Leopoldo, Metropolitan Region of Porto Alegre, state of Rio Grande do Sul. The objective of this study was to understand how ATHIS process can contribute to the promotion of healthy habitat for low-income populations. The data collection techniques used were: document analysis, non-participant unsystematic observation and semi-structured interviews. The results showed that: i) ATHIS involving the population through a participatory process, contributes to the improvement of the habitability conditions of the populations involved; ii) ATHIS can contribute to the consolidation of a healthy habitat by improving the quality of the urban and housing environment, with emphasis on basic sanitation conditions.La precariedad de las condiciones de vivienda en Brasil tiene serias implicaciones para un hábitat saludable. En 2020, el advenimiento de la pandemia Covid-19 agregó urgencia a las discusiones sobre viviendas saludables, especialmente en las afueras de las ciudades; donde se encuentran las mayores necesidades: habitabilidad, abastecimiento de agua, infraestructura y saneamiento básico. En este contexto, la aplicación de la Ley 11.888 de 2008, de Asistencia Técnica en Vivienda de Interés Social (ATHIS), ha facilitado el acceso al trabajo de los profesionales de la arquitectura para la población de bajos ingresos. Además, las iniciativas de ATHIS han buscado consolidar proyectos de vivienda de interés social que resulten en la producción de viviendas más saludables. Este artículo presenta un estudio de caso sobre el proceso de desarrollo de ATHIS para una comunidad de 68 familias en la ciudad de São Leopoldo, Región Metropolitana de Porto Alegre, estado de Rio Grande do Sul. El objetivo de este estudio es comprender cómo el proceso de ATHIS pudo contribuir a la promoción de un hábitat saludable en esa comunidad. Las técnicas de recolección de datos utilizadas fueron: análisis de documentos, observación no sistemática no participante y entrevistas semiestructuradas. Los resultados mostraron que: i) ATHIS, involucrando a la población a través de un proceso participativo, contribuye a mejorar las condiciones de vida de las poblaciones involucradas; ii) ATHIS puede contribuir a la consolidación de un hábitat saludable mejorando la calidad del entorno urbano y habitacional, destacando las condiciones de saneamiento básico.A precariedade das condições de moradia no Brasil tem sérias implicações sobre o habitat saudável. No ano de 2020, o advento da pandemia de Covid-19 acrescentou urgência às discussões acerca da habitação saudável, principalmente nas periferias das cidades; onde se encontram as maiores carências: de habitabilidade, de fornecimento de água, de infraestrutura e saneamento básico. Nesse contexto, a aplicação da Lei 11.888 de 2008, da Assistência Técnica em Habitação de Interesse Social (ATHIS), tem oportunizado o acesso ao trabalho dos profissionais de arquitetura para a população de baixa renda. Além disso, as iniciativas de ATHIS têm buscado a consolidação de projetos de habitação de interesse social que resultem na produção de unidades habitacionais mais saudáveis. O presente artigo apresenta um estudo de caso sobre o processo de desenvolvimento da ATHIS para uma comunidade de 68 famílias da cidade de São Leopoldo, Região Metropolitana de Porto Alegre, estado do Rio Grande do Sul. O objetivo deste estudo é compreender como o processo de ATHIS pôde contribuir para a promoção do habitat saudável naquela comunidade. As técnicas de coleta de dados utilizadas foram: análise de documentos, observação assistemática não-participante e entrevistas semiestruturadas. Os resultados permitiram constatar que:  i) a ATHIS envolvendo a população através de processo participativo, apresenta contribuições para a melhoria das condições de habitabilidade das populações envolvidas; ii) a ATHIS pode contribuir para a consolidação de um habitat saudável através da melhoria da qualidade do ambiente urbano e habitacional, destacando-se as condições básicas de saneamento

Incidence and pattern of "de novo"hepatocellular carcinoma in HCV patients treated with oral DAAs,

This study evaluates the possibility of increased risk of HCC during and after DAAs treatment in HCV patients with advanced liver disease