Surge damping analysis in pipe systems: modelling and experiments

The current study focuses on the analysis of pressure surge damping in single pipeline systems generated by a fast change of flow, conditions. A dimensionless form of pressurised transient flow equations was developed. presenting the main advantage of being independent of the system characteristics. In lack of flow velocity profiles. the unsteady friction in turbulent regimes is analysed based on two new empirical corrective-coefficients associated with local and convective acceleration terms. A new, surge damping approach is also presented taking into account the pressure peak time variation. The observed attenuation effect in the pressure wave for high deformable pipe materials can be described by a combination of the non-elastic behaviour of the pipe-wall with steady and unsteady friction effects. Several simulations and experimental tests have been carried out. in order to analyse the dynamic response of single pipelines with different characteristics, such as pipe materials. diameters. thickness. lengths and transient conditions.

A new cloning system based on the OprI lipoprotein for the production of recombinant bacterial cell wall-derived immunogenic formulations

The conjugation of antigens with ligands of pattern recognition receptors (PRR) is emerging as a promising strategy for the modulation of specific immunity. Here, we describe a new Escherichia coli system for the cloning and expression of heterologous antigens in fusion with the OprI lipoprotein, a TLR ligand from the Pseudomonas aeruginosa outer membrane (OM). Analysis of the OprI expressed by this system reveals a triacylated lipid moiety mainly composed by palmitic acid residues. By offering a tight regulation of expression and allowing for antigen purification by metal affinity chromatography, the new system circumvents the major drawbacks of former versions. In addition, the anchoring of OprI to the OM of the host cell is further explored for the production of novel recombinant bacterial cell wall-derived formulations (OM fragments and OM vesicles) with distinct potential for PRR activation. As an example, the African swine fever virus ORF A104R was cloned and the recombinant antigen was obtained in the three formulations. Overall, our results validate a new system suitable for the production of immunogenic formulations that can be used for the development of experimental vaccines and for studies on the modulation of acquired immunity.

Determination of chitin content in fungal cell wall: an alternative flow cytometric method

The conventional methods used to evaluate chitin content in fungi, such as biochemical assessment of glucosamine release after acid hydrolysis or epifluorescence microscopy, are low throughput, laborious, time-consuming, and cannot evaluate a large number of cells. We developed a flow cytometric assay, efficient, and fast, based on Calcofluor White staining to measure chitin content in yeast cells. A staining index was defined, its value was directly related to chitin amount and taking into consideration the different levels of autofluorecence. Twenty-two Candida spp. and four Cryptococcus neoformans clinical isolates with distinct susceptibility profiles to caspofungin were evaluated. Candida albicans clinical isolate SC5314, and isogenic strains with deletions in chitin synthase 3 (chs3Δ/chs3Δ) and genes encoding predicted Glycosyl Phosphatidyl Inositol (GPI)-anchored proteins (pga31Δ/Δ and pga62Δ/Δ), were used as controls. As expected, the wild-type strain displayed a significant higher chitin content (P < 0.001) than chs3Δ/chs3Δ and pga31Δ/Δ especially in the presence of caspofungin. Ca. parapsilosis, Ca. tropicalis, and Ca. albicans showed higher cell wall chitin content. Although no relationship between chitin content and antifungal drug susceptibility phenotype was found, an association was established between the paradoxical growth effect in the presence of high caspofungin concentrations and the chitin content. This novel flow cytometry protocol revealed to be a simple and reliable assay to estimate cell wall chitin content of fungi.

Lean thinking: Glass Wall Management

Sendo os desperdícios “Waste” associados à atividade industrial em Portugal e nos mercados globais e os seus custos inerentes, uma das maiores preocupações a todos os níveis de gestão empresarial, a filosofia “Lean” nasce como ajuda e encaminhamento na solução desta problemática. O conceito “Lean”, no que se refere à indústria, desde sempre e até aos dias de hoje, tem uma enorme ênfase, com a adoção deste conceito.Verificam-se bons resultados ao nível da redução de custos, melhoria da qualidade geral dos artigos produzidos, no controlo da produção em geral e é uma poderosa ferramenta no estreitamento da relação entre os diferentes intervenientes da cadeia de valor de determinado produto, sobretudo com fornecedores e com clientes. Com “Lean Management” e “Glass Wall Management”, em ambientes onde as empresas mais avançadas estão a procurar melhorar a sua competitividade através de uma gestão transparente (“Glass Wall Management”), a partir da qual, “toda informação relevante é compartilhada de maneira a que todos entendam a situação”(Suzaki, K, 1993), ganha cada vez mais importância a existência de uma estrutura organizacional que permita esta transparência e a consequente maturidade das empresas. Neste trabalho foram descritos alguns processos de gestão transparente desenvolvidos nos últimos dois anos numa PME portuguesa, aprofundando o processo de gestão transparente vigente e as ferramentas que ajudam a empresa e que na sua globalidade poderão ser extrapoladas a outras PME Portuguesas de modo que a informação importante e relevante seja partilhada por todos os intervenientes na estrutura empresarial, sendo entendida e desenvolvida por todos através de Edições e Revisões aos documentos mais importantes da empresa. Neste estudo foram contactadas vinte e uma PME’S portuguesas de tipologia de produção MTO (Make to Order) do sector dos estofos/mobiliário, e solicitado o preenchimento de um Questionário, tendo como fim em vista, a verificação do uso desta metodologia “Glass Wall Management” à escala empresarial portuguesa e a interpretação do Conceito Geral “Lean” como filosofia de redução de materiais, tempos e custos.

a-SiH p-i-n structures with extreme i-layer thickness

We present measurements and numerical simulation of a-Si:H p-i-n detectors with a wide range of intrinsic layer thickness between 2 and 10 pm. Such a large active layer thickness is required in applications like elementary particle detectors or X-ray detectors. For large thickness and depending on the applied bias, we observe a sharp peak in the spectral response in the red region near 700 nm. Simulation results obtained with the program ASCA are in agreement with the measurement and permit the explanation of the experimental data. In thick samples holes recombine or are trapped before reaching the contacts, and the conduction mechanism is fully electron dominated. As a consequence, the peak position in the spectral response is located near the optical band gap of the a-Si:H i-layer. (C) 2009 Elsevier B.V. All rights reserved.

Film thickness in a ball-on-disc contact lubricated with greases, bleed oils and base oils

Three different lubricating greases and their bleed and base oils were compared in terms of film thickness in a ball-on-disc test rig through optical interferometry. The theoretical values calculated according to Hamrock's equation are in close agreement with the base oil film thickness measurements, which validates the selected experimental methodology. The grease and bleed oil film thickness under fully flooded lubrication conditions presented quite similar behaviour and levels. Therefore, the grease film thickness under full film conditions might be predicted using their bleed oil properties, namely the viscosity and pressure-viscosity coefficient. The base and bleed oil lubricant parameter LP are proportional to the measured film thickness. A relationship between grease and the corresponding bleed oil film thickness was evidenced.

A lightweight indoor localization model based on motley-keenan and COST

This paper presents a novel approach to WLAN propagation models for use in indoor localization. The major goal of this work is to eliminate the need for in situ data collection to generate the Fingerprinting map, instead, it is generated by using analytical propagation models such as: COST Multi-Wall, COST 231 average wall and Motley- Keenan. As Location Estimation Algorithms kNN (K-Nearest Neighbour) and WkNN (Weighted K-Nearest Neighbour) were used to determine the accuracy of the proposed technique. This work is based on analytical and measurement tools to determine which path loss propagation models are better for location estimation applications, based on Receive Signal Strength Indicator (RSSI).This study presents different proposals for choosing the most appropriate values for the models parameters, like obstacles attenuation and coefficients. Some adjustments to these models, particularly to Motley-Keenan, considering the thickness of walls, are proposed. The best found solution is based on the adjusted Motley-Keenan and COST models that allows to obtain the propagation loss estimation for several environments.Results obtained from two testing scenarios showed the reliability of the adjustments, providing smaller errors in the measured values values in comparison with the predicted values.

The influence of geometric factors on the wall shear stress distribution in realistic human coronary arteries

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Biomédica. A presente dissertação foi desenvolvida no Erasmus Medical Center em Roterdão, Holanda

Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition method

Adhesive bonding is nowadays a serious candidate to replace methods such as fastening or riveting, because of attractive mechanical properties. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. This work studies the tensile behaviour of adhesive joints between aluminium adherends considering different values of adherend thickness (h) and the double-cantilever beam (DCB) test. The experimental work consists of the definition of the tensile fracture toughness (GIC) for the different joint configurations. A conventional fracture characterization method was used, together with a J-integral approach, that take into account the plasticity effects occurring in the adhesive layer. An optical measurement method is used for the evaluation of crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, a comparative evaluation between bonded systems with different values of adherend thickness is carried out and complete fracture data is provided in tension for the subsequent strength prediction of joints with identical conditions.

Multiobjective optimization of cold-formed steel columns

The optimal design of cold-formed steel columns is addressed in this paper, with two objectives: maximize the local-global buckling strength and maximize the distortional buckling strength. The design variables of the problem are the angles of orientation of cross-section wall elements the thickness and width of the steel sheet that forms the cross-section are fixed. The elastic local, distortional and global buckling loads are determined using Finite Strip Method (CUFSM) and the strength of cold-formed steel columns (with given length) is calculated using the Direct Strength Method (DSM). The bi-objective optimization problem is solved using the Direct MultiSearch (DMS) method, which does not use any derivatives of the objective functions. Trade-off Pareto optimal fronts are obtained separately for symmetric and anti-symmetric cross-section shapes. The results are analyzed and further discussed, and some interesting conclusions about the individual strengths (local-global and distortional) are found.

Study in real conditions and in laboratory of the application of expanded agglomerated cork as exterior wall covering

The interest of the study on the implementation of expanded agglomerated cork as exterior wall covering derives from two critical factors in a perspective of sustainable development: the use of a product consisting of a renewable natural material-cork-and the concern to contribute to greater sustainability in construction. The study aims to assess the feasibility of its use by analyzing the corresponding behaviour under different conditions. Since this application is relatively recent, only about ten years old, there is still much to learn about the reliability of its long-term properties. In this context, this study aims to deepen and approach aspects, some of them poorly studied and even unknown, that deal with characteristics that will make the agglomerate a good choice for exterior wall covering. The analysis of these and other characteristics is being performed by testing both under actual exposure conditions, on an experimental cell at LNEC, and on laboratory. In this paper the main laboratory tests are presented and the obtained results are compared with the outcome of the field study. © (2015) Trans Tech Publications, Switzerland.

The thickness of the transport layer in stratified geomorphic flows

River Flow 2010

CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.