Effect of section thickness on fatigue performance of laser sintered nylon 12

Laser Sintering offers manufacturers freedom of design, which enables creating parts with complex geometries. However, very little investigation has been made into the effects of geometry on mechanical properties of the parts. In the present study, Laser Sintered Nylon 12 parts with different section thickness are subjected to displacement controlled tension-tension and force-controlled fully reversed fatigue loading to investigate the effect of geometry on their fatigue behavior. Section thickness of the parts is shown to have no significant influence on the fatigue behavior under tension only loading. However, fatigue life of parts under fully reversed loading is shown to increase with section thickness

Comparison between bubbling and turbulent regime for the simulation of batch pharmaceutical powders fluidized bed drying

[EN] The two-phase theory has been frequently used to model fluidised bed drying. At high air velocities, a transition from the bubbling regime to the turbulent regime may occur. In this work, we compare a bubbling model and a turbulent model for the simulation of a two pharmaceutical powders drying in a pilot plant and an industrial plant fluidised bed. The bubbling model was based on a discrete variable bubble size. Heat and mass transfer coefficients were based on the Kunii and Levenspiel correlation [1]. Flow regime was supposed to be completely mixed for the emulsion phase. For the turbulent model, the bubble size is not anymore discrete but continuous and bubble phase is less distinguishable than in the bubbling regime. Heat and mass transfer were those proposed by Foka[2]. In addition, the freeboard section was considered since high entrainment is specific of this regime. Gas backmixing was taken into account by considering a plug flow with axial dispersion for the interstitial gas flow. The bubble phase being dilute, was modeled by a plug flow. A plug flow was also considered for the freeboard gas. The solid phase was supposed to be completely mixed. The bubbling regime simulation gave good agreement with experiment in the case of the pilot plant experiment, while the turbulent model better simulated the industrial scale experiment.Zammouri, A.; Boudhrioua Mihoubi, N.; Kechaou, N. (2018). Comparison between bubbling and turbulent regime for the simulation of batch pharmaceutical powders fluidized bed drying. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 457-464. https://doi.org/10.4995/IDS2018.2018.7703OCS45746

Musées, colonialisme, indépendance : figures du donateur

Cet article pose, dans une perspective maussienne, la question du don aux musées d’Alger sur la longue durée, de la colonisation à nos jours. Il suffit de rappeler que le premier musée fondé en Afrique le fut dans la colonie française, en 1835, pour comprendre le caractère paradigmatique du rôle des dons et des donateurs dans la formation des collections en contexte colonial. Le cadre chronologique – de 1835 à l’Algérie contemporaine – permet de comprendre le rôle structurant du don et de situer les figures des donateurs dans l’histoire politique. Pour autant le don ne doit pas seulement être considéré comme une catégorie muséologique mais comme une forme de transaction. Son étude implique de contextualiser précisément les conditions de l’échange : il peut être accepté totalement ou constituer une forme de transaction incomplète. Ce dernier cas fait apparaître la hiérarchisation des musées à l’époque coloniale comme les postulations divergentes de l’Algérie indépendante. Enfin, c’est à l’aune d’une pragmatique du goût qu’est questionné l’attachement parfois paradoxal que l’on observe aujourd’hui pour l’ethnographie, l’orientalisme et l’art moderne.From a Maussian perspective, this article raises the question of donations to museums in Algiers over the long term, from colonization to the present day. To understand the paradigmatic nature of the role of donations and donors in the formations of collections in the colonial context, it is enough to remember that the first museum founded in Africa was in the French colony in 1835. The chronological framework – from 1835 until contemporary Algeria – helps to understand the structuring role of donations and to situate the figures of donors in political history. However, donations should not only be considered a museological category, but also as a form of transaction. This study aims to precisely contextualize the conditions of exchange: it can be accepted in full or constitute an incomplete transaction. The latter shows the hierarchization of colonial-era museums as the divergent representations of independent Algeria. Finally, the sometimes paradoxical attachment to ethnography, orientalism, and modern art is questioned on the basis of a pragmatic approach to taste (A. Hennion).Einer von Mauss erarbeiteten Perspektive folgend befasst sich der Artikel in langfristiger Hinsicht mit der Frage nach den Schenkungen an die Museen Algiers, von der Kolonialisierung bis heute. Es genügt, in Erinnerung zu rufen, dass die erste Museumsgründung in Afrika 1835 in der französischen Kolonie geschah, um den paradigmatischen Charakter bezüglich der Rolle von Schenkungen und Stiftern für Sammlungsgenese im Kolonialkontext zu erfassen. Der chronologische Rahmen – von 1835 bis zum heutigen Algerien – ermöglicht es, ein Verständnis für die strukturierende Funktion von Schenkungen zu gewinnen und die Figuren der Stifter innerhalb der politischen Geschichte zu verorten. Insofern dürfen Schenkungen nicht ausschließlich als museologische Kategorie, sondern zugleich als eine Form von Transaktion erachtet werden. Ihre Erforschung bedarf einer präzisen Kontextualisierung der Bedingungen des Austauschs: Dieser kann sowohl auf vollkommenem Einverständnis wie auf einer unvollständigen Transaktion beruhen. Die letztere Konstellation bringt die Hierarchisierung der Museen in der Kolonialzeit sowie die unterschiedlichen Anforderungen des unabhängigen Algeriens zum Vorschein. Zuletzt gilt es, mit dem Maßstab einer Pragmatik des Geschmacks (A. Hennion) die zuweilen paradoxale Fixierung zu untersuchen, die sich in Ethnographie, Orientalismus und der modernen Kunst beobachten lässt.Il presente articolo pone in una prospettiva maussiana la questione delle donazioni ai musei di Algeri nel periodo compreso tra la colonizzazione e i giorni nostri. A questo proposito, per comprendere il carattere paradigmatico del ruolo delle donazioni e dei donatori nella formazione delle collezioni in contesto coloniale, è sufficiente ricordare che il museo fondato in Algeria nel 1835 fu il primo in Africa. Il quadro cronologico – dal 1835 all’Algeria contemporanea – permette dunque di comprendere il ruolo strutturante delle donazioni e di inquadrare le figure dei donatori nella storia politica del paese. La donazione non deve essere considerata solamente come una categoria museologica, ma anche come una forma di transazione. Il suo studio richiede una contestualizzazione precisa delle condizioni di scambio: la donazione può infatti essere completamente accettata o costituire una forma di transazione incompleta. Quest’ultimo caso mostra tanto la gerarchizzazione dei musei in epoca coloniale che le differenti problematiche dell’Algeria indipendente. L’attaccamento alle volte perfino paradossale che si osserva oggi nei confronti dell’etnografia, dell’orientalismo e dell’arte moderna è infine analizzato alla luce di una prammatica del gusto.A partir de una perspectiva mausieana, este artículo trata la cuestión de la donación a los museos de Argelia en un periodo de larga duración, desde la colonización hasta nuestros días. Basta recordar que el primer museo fundado en África data de la colonia francesa, en 1835, para comprender el carácter paradigmático del rol de las donaciones y de los donantes en la formación de las colecciones en el contexto colonial. El marco cronológico – de 1835 a la Argelia contemporánea – permite comprender el rol estructural de la donación y de situar las figuras de los donadores en la historia política. No obstante, la donación no debe ser solo considerada como una categoría museológica sino como una forma de transacción. Su estudio implica una contextualización de las condiciones de intercambio: éste puede ser aceptado totalmente o puede constituir una forma de transacción incompleta. Este último caso devela la jerarquización de los museos en la época colonial como representantes de los posicionamientos divergentes de la Argelia independiente. Por último, a la luz de una pragmática del gusto se cuestiona el apego, a veces paradójico, que se observa hoy por la etnografía, el orientalismo y el arte moderno

Thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds

[EN] This investigation examines and compares the water sorption isotherms and the thermodynamic properties of two pharmaceutical preparations (Hypril and Azix) intended to be manufactured with the same process plant and equipment. The moisture equilibrium isotherms were determined at 50, 60 and 70 °C using a gravimetric technique. Five isotherm models were explored for their fitting to the experimental data. Azix showed sigmoid type II isotherms while Hypril showed type III isotherms according to the BET classification. All investigated models fitted well the water sorption isotherms of Hypril. By contrast, only GAB and Adam and Shove equations gave appropriate fit to the experimental data of Azix. For both formulations, the isosteric heat and the differential entropy decreased sharply with the increase of equilibrium moisture content to minimum values and thereafter remain constant. In the case of Azix, the integral enthalpy decreased with equilibrium moisture content while the integral entropy increased until reaching a constant value. Contrariwise, Hypril showed decreasing of the integral enthalpy and entropy with the equilibrium moisture content.Zammouri, A.; Ben Zid, M.; Kechaou, N.; Boudhrioua Mihoubi, N. (2018). Thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 449-456. https://doi.org/10.4995/IDS2018.2018.7702OCS44945

Study of Foaming Properties and Effect of the Isomeric Distribution of Some Anionic Surfactants

Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized method very similar to the Ross–Miles foaming tests to identify which surfactants are suitable for applications requiring high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the critical micellar concentrations and at 25 C for both the samples

Prediction of axial capacity of piles driven in non-cohesive soils based on neural networks approach

This paper presents an application of two advanced approaches, Artificial Neural Networks (ANN) and Princi­pal Component Analysis (PCA) in predicting the axial pile capacity. The combination of these two approaches allowed the development of an ANN model that provides more accurate axial capacity predictions. The model makes use of Back-Propagation Multi-Layer Perceptron (BPMLP) with Bayesian Regularization (BR), and it is established through the incorporation of approximately 415 data sets obtained from data published in the literature for a wide range of un-cemented soils and pile configurations. The compiled database includes, respectively 247 and 168 loading tests on large-and low-displacement driven piles. The contributions of the soil above and below pile toe to the pile base resistance are pre-evaluated using separate finite element (FE) analyses. The assessment of the predictive performance of the new method against a number of traditional SPT-based approaches indicates that the developed model has attractive capabili­ties and advantages that render it a promising tool. To facilitate its use, the developed model is translated into simple design equations based on statistical approaches

Coxiella burnetii, the causative agent of Q fever in Saudi Arabia: molecular detection from camel and other domestic livestock

AbstractObjectiveTo detect Coxiella burnetii (C. burnetii) DNA in clinical specimens from camel, goats, cattle and sheep in the Kingdom of Saudi Arabia.MethodsA total of 367 clinical samples including blood, milk, faeces and urine were collected from different livestock and subjected to PCR amplification using primers which amplify transposon-like region and transposase gene.ResultsPositive amplification from both regions was obtained from camel, goats and cattle but not from sheep. A percentage of 10.8% samples yielded positive PCR amplification from both blood and milk, where 15 of 139 blood and 16 of 148 milk samples were positive. Faeces and urine showed higher percentages of positive samples reaching 40.8% and 23.8% respectively.ConclusionsThe preferred route of shedding in camel appeared to be the faeces followed by urine, while that of goats appeared to be the faeces and that of the cattle appeared to be the milk

Three-dimensionalenvironment and vascularization induce osteogenic maturation of human adipose-derived stem cells comparable to that of bone-derived progenitors

While human adipose-derived stem cells (hADSCs) are known to possess osteogenic differentiation potential, the bone tissues formed are generally considered rudimentary and immature compared with those made by bone-derived precursor cells such as human bone marrow-derived mesenchymal stem cells (hBMSCs) and less commonly studied human calvarium osteoprogenitor cells (hOPs). Traditional differentiation protocols have tended to focus on osteoinduction of hADSCs through the addition of osteogenic differentiation media or use of stimulatory bioactive scaffolds which have not resulted in mature bone formation. Here, we tested the hypothesis that by reproducing the physical as well as biochemical bone microenvironment through the use of three-dimensional (3D) culture and vascularization we could enhance osteogenic maturation in hADSCs. In addition to biomolecular characterization, we performed structural analysis through extracellular collagen alignment and mineral density in our bone tissue engineered samples to evaluate osteogenic maturation. We further compared bone formed by hADSCs, hBMSCs, and hOPs against mature human pediatric calvarial bone, yet not extensively investigated. Although bone generated by all three cell types was still less mature than native pediatric bone, a fibrin-based 3D microenvironment together with vascularization boosted osteogenic maturation of hADSC making it similar to that of bone-derived osteoprogenitors. This demonstrates the important role of vascularization and 3D culture in driving osteogenic maturation of cells easily available but constitutively less committed to this lineage and suggests a crucial avenue for recreating the bone microenvironment for tissue engineering of mature craniofacial bone tissues from pediatric hADSCs, as well as hBMSCs and hOPs

Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.

BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating

Short communication: Influence of vitamins C and E on sperm motility of rabbit bucks

[EN] The objective of the study is to investigate the effect of vitamin C and E supplementation on rabbit sperm motility. Forty INAT breed bucks aged 8.5 mo were divided into 2 groups: control group (C) and treated group (T) receiving vitamins C (1 g/L) and E (1 g/L) incorporated in the drinking water. Semen was collected using an artificial vagina over 6 wk (C, total ejaculates=81; T, total ejaculates=76). The massal motility (MM) was evaluated in the fresh and raw semen. Then, the individual motility at 0 (IM0), 2 (IM2) and 4 h (IM4) after semen collection was determined in diluted semen and conserved at +4°C for the 2 groups. MM was higher in T than in C group (P=0.0012). However, the individual motilities IM0, IM2 and IM4 did not vary between the 2 groups. In conclusion, the supplementation of vitamins C and E in the drinking water for rabbit influenced only the MM in both fresh and raw semen.Najjar Ben Maâtoug, A.; Ben Saïd, S.; Najjar, T.; Kalamoun, S.; Ben Khalifa, N.; Ben Aïchae, E.; Ben Mrad, M. (2013). Short communication: Influence of vitamins C and E on sperm motility of rabbit bucks. World Rabbit Science. 21(1):45-48. doi:10.4995/wrs.2013.1174.SWORD454821