Size fractionation by slalom chromatography and hydrodynamic chromatography

Hydrodynamic chromatography, also called separation by flow, is based on the use of the parabolic flow profile occurring in open capillaries or in the pores from a column filled with non-porous particles. The hydrodynamic chromatography separation medium, if any, is much simpler than that from size exclusion chromatography (porous particles), the former technique being used in the size-fractionation of many colloids and macromolecules. The transition between hydrodynamic chromatography (obtained using low flow rates) and slalom chromatography (obtained using high flow rates) was reported in studies related with the migration behaviour of proteins, plasmid DNAs and double stranded DNAs. Slalom chromatography is mainly applied in the size-fractionation of large double stranded DNA fragments and may compete with electrophoretic techniques. In the present paper it is discussed the main patents, applications, advantages and drawbacks related to hydrodynamic chromatography and slalom chromatography, as well as some strategies that may improve the performance of these simple size-fractionation techniques

Passive systems for buildings using buoyancy-driven airflows

The need for countries to become less dependent on fossil fuels has been a determining factor in recent years due to increasing energy and comfort concerns in modern building design. Therefore, the maximization of the use of renewable energies, like the sun, and the use of natural energy flows become strategies to explore. There are already passive building systems that show interesting performances. Different studies have proved that the above-mentioned systems can lead to important energy savings. However, these systems have their limitations and new innovative building solutions are needed, mainly in the field of passive solar energy collection and natural ventilation strategies. Furthermore, building envelopes face nowadays a new paradigm in which buildings need to be more reactive and adaptive to external climate changes and indoor thermal comfort demands. Hence, this paper makes a review of the most recent patents on building solar air systems that make use of solar energy to induce the buoyancy effect for heating, cooling and ventilating. The patents presented demonstrate the increasing tendency in the development of building passive solutions that can satisfy, in just one system, more than one role: heating, cooling and ventilation.The present paper was performed within the framework of a research project on Low Energy/High Comfort Building Renewal, PTDC/ECM/67373/2006, sponsored by the Portuguese Foundation for Science and Technology (FCT)

Numerical prediction of velocity, pressure and shear rate distributions in stenosed channels

Wall shear rates and pressure developed in circulatory system play an important role on the development of some clinical problems such as atherosclerosis and thrombosis. In the present work, blood flow behaviour was numerically studied in simplified domains and several relevant local properties were determined. The stenosis degree was varied in the distinct studied channels and blood rheology was described by three different models – constant viscosity, power-law model and Carreau model. Pressure attains maximum values in the wall of the atheroma and shear rates achieved maximum values in the top of the atheroma. It was also observed that, with the studied flows, the predictions for velocity and shear rate using non-Newtonian models were very similar. This observation can be explained by the magnitude of the obtained shear rates.The authors acknowledge the financial support provided by: PTDC/ SAU-BEB/108728/2008 and PTDC/SAU-BEB/105650/2008 from the FCT (Science and Technology Foundation) and COMPETE, Portugal

New plates for different types of plate heat exchangers

The first patent for a plate heat exchanger was granted in 1878 to Albretch Dracke, a German inventor. The commercial embodiment of these equipments has become available in 1923. However, the plate heat exchanger development race began in the 1930’s and these gasketed plate and frame heat exchangers were mainly used as pasteurizers (e.g. for milk and beer). Industrial plate heat exchangers were introduced in the 1950’s and initially they were converted dairy models. Brazed plate heat exchangers were developed in the late 1970’s. However, copper brazed units did not start selling until the early 80’s. Nickel brazing came to market around ten years later, since copper presents compatibility problems with some streams (e.g. ammonia). All-welded and semi-welded (laser weld) plate heat exchangers were developed during the 1980’s and early 90’s. Shell and plate heat exchangers were recently introduced in the market and can withstand relatively high pressures and temperatures, as the shell and tube does. The fusion bonded plate heat exchangers (100% stainless steel) are a technology from the 21st century, these equipments being more durable than brazed plate heat exchangers. The plates are the most important elements from the different plate heat exchangers mentioned above. This paper initially introduces the gasketed plate and frame heat exchanger and common chevron-type plates. Resorting to computer fluid dynamics techniques, the complex 3D flow in cross-corrugated chevron-type plate heat exchanger passages is visualized. Recent patents related with the plates from different plate heat exchangers are then outlined

Architectural rehabilitation and conservation processes informed by augmented reality

WOS:000330320600043The goal of the presented research is to explore human-machine interaction and to study how Augmented Reality (AR) may be a potential tool to inform Architectural Rehabilitation and Conservation processes. Nowadays obtaining data to inform both architecture projects and real estate investments is a very bureaucratic process. City councils technicians suffers from the same difficulties when are in fieldwork to do inspections and lack a complete sort of information. This proposal considers that the use of mobile technologies as smart phones and tablets can empower these technicians to obtain building related data. The specific goal of the study aims to develop a data model and an interface that can be made available to professionals which allows an efficiently reply to the user’s needs as the system enables the gathering of updated information considering a particular building.info:eu-repo/semantics/publishedVersio

Tortuosity variation in a low density binary particulate bed

The importance of particle size ratio and particle composition in the properties of a mixed bed is well known. Nevertheless, the dependence of the bed channel tortuosity T on the porosity ε in the form T=1/εn, where n is assumed to be a constant, shows that the value of n depends on the properties of the packed bed. For loose packing, experimental data for binary mixtures of glass beads of a size ratio from 1 up to 53.8 was analysed in terms of porosity, tortuosity and permeability. The packing procedure was performed without intensive compacting methods e.g. vibration, etc. Obtained results show that the parameter n is a function of the volume fraction of large particles xD and, for spherical particles, lies in the range 0.4–0.5. The explanation for this variation is (1) a distortion effect on the small particles arrangement occurring near the large particle surface; (2) in the region of minimum porosity, near contact points of large particles, the occurrence of dead zones that are free of small particles. A relationship accounting for this effect is proposed that may be useful for the analysis of transport phenomena in granular bed filters, chromatographic columns, etc.Fundação para a Ciência e a Tecnologia FCT); FEDE

Application of binary packing for starch separation by hydrodynamic chromatography

Columns packed with commercial glass beads of 5 and 19 microns average diameter and binary mixtures with finest fraction of 5 micron (30 % volume fraction of the mixture) were used to analyse starch by hydrodynamic chromatography (HDC). Experiments were carried out at 3 and 15 ºC. The observed resolution increased with the application of binary packing as compared with single-size packing. The best results were obtained at starch’s amylopectin and amylose separation with a glass beads mixture (5 + 19 micron) at 3ºC. In what concerns amylopectin and amylose separation, a lower pressure drop were obtained for the mixed binary packing when compared with the packing containing uniform 5 micron glass beads. For the Hylon VII starch RRT were 0.777 and 0.964 for amylopectin (AP) and amylose (AM), respectively, while for the Tapioca starch the obtained RRTs were 0.799 and 0.923. Application of unbound glass beads as column packing might reduce equipment and running costs in preparative scale separations.Fundação para a Ciência e a Tecnologia (FCT) .FEDER - projecto POCI_EQU_58337/200

Plano de emergência interno (PEI) : Mercado Municipal do Pinhal Novo

Pós-Graduação em Segurança e Higiene no TrabalhoNo âmbito do curso de Mestrado em Segurança e Higiene no Trabalho, foi elaborado o presente projeto final referente ao 1° ano do curso, no qual se pretende expor a aplicação dos conteúdos seccionados no decorrer do curso, bem como as competências adquiridas durante a componente prática em contexto real de trabalho realizada no Mercado Municipal de Pinhal Novo, edifício público propriedade da Câmara Municipal de Palmela. Este projeto denominado "Plano de Emergência Interno", tem como objetivo a elaboração de um Plano de Emergência Interno para o Mercado Municipal de Pinhal Novo. No Plano, é caracterizado o edifício, em termos físicos, técnicos e humanos, são identificados os riscos internos e externos inerentes e os meios de segurança contra incêndios disponíveis, tendo em conta a organização interna da emergência e de acordo com a legislação em vigor. A metodologia utilizada, baseia-se essencialmente na observação direta no edifício, através de uma inspeção técnica "in loco", em suporte documental sobre o edifício e em pesquisa bibliográfica. Com a elaboração deste Plano de Emergência Interno, pretende-se que o edifício do Mercado Municipal de Pinhal Novo, passe a dar cumprimento aos requisitos legais e contribua assim para a promoção da segurança dos seus funcionários, colaboradores e munícipes em geral.No âmbito do curso de Mestrado em Segurança e Higiene no Trabalho, foi elaborado o presente projeto final referente ao 1° ano do curso, no qual se pretende expor a aplicação dos conteúdos seccionados no decorrer do curso, bem como as competências adquiridas durante a componente prática em contexto real de trabalho realizada no Mercado Municipal de Pinhal Novo, edifício público propriedade da Câmara Municipal de Palmela. Este projeto denominado "Plano de Emergência Interno", tem como objetivo a elaboração de um Plano de Emergência Interno para o Mercado Municipal de Pinhal Novo. No Plano, é caracterizado o edifício, em termos físicos, técnicos e humanos, são identificados os riscos internos e externos inerentes e os meios de segurança contra incêndios disponíveis, tendo em conta a organização interna da emergência e de acordo com a legislação em vigor. A metodologia utilizada, baseia-se essencialmente na observação direta no edifício, através de uma inspeção técnica "in loco", em suporte documental sobre o edifício e em pesquisa bibliográfica. Com a elaboração deste Plano de Emergência Interno, pretende-se que o edifício do Mercado Municipal de Pinhal Novo, passe a dar cumprimento aos requisitos legais e contribua assim para a promoção da segurança dos seus funcionários, colaboradores e munícipes em geral

Effect of real particles packing with large size ratio on porosity and tortuosity of filter bed

The complexity of processes involved in the formation of granular beds results in limited information about permeability κ , which directly rela tes with packing porosity ε and tortuosity T . For a mixed bed of particles significantly different in size, the influence of packing affects permeability. For a better understanding of the underlying relationship between κ , ε , and T in mixed beds of particles significantly different in size, simplified porous media model of binary mixture of spheres were used. Boundary analysis of the binary packing showed that the approach based on the fractional porosity of large and small size particle fractions gives a tool for ε control. This approach allows a new insight into the mixture structure and provides explanation for the different types of the obtained porosity. Binary packing of glass beads with size ratios 13.3, 20, and 26.7 were investigated. As a basic relation for the dependence of T on ε, at different volume fraction xD of large particles in the mixture, the formula T=1/ εⁿ was used. The obtained experimental results show that the parameter n is a function of the packing content xD and may vary in the range of 0.4-0.5. The reason for n variation was explained by the wall effect of the small particles arrangement occurring near the large particles surface. A model accounting for this effect is proposed and may be useful for transport phenomena analysis in granular bed filters.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/EQU/37500/2001.União Europeia (UE). Fundo Europeu de Desenvolvimento Regional (FEDER)

Particulate binary mixtures : dependence of packing porosity on particle size ratio

Binary mixtures with significant size ratios are scarcely studied. Yet, contaminants of chromatographic columns or ion-exchange resins have size ratios of delta < 0.1. Binary mixtures of glass beads with delta = 0.1-0.0375 were used experimentally to measure packing porosity. Simultaneously, a significant number of published data was analyzed. A linear mixing model was adopted to predict the porosity of each particle fraction in the binary mixture. Deviations from the model may be caused by wedging of small particles between the large ones. Large particles may disturb the porous medium properties by inducing a wall effect over the small particles. Wedging analysis led to the conclusion that, for delta < 0.01, its effect is insignificant. The wall effect yields an additional void around the large particles as long as delta > 0.0035. For delta < 0.0035, the small particles form a monosized dense packing and both wedging and wall effects become negligible.Fundação para a Ciência e a Tecnologia (FCT) e FEDER – POCTI/EQU/37500/2001