Search results for "WOOD"

CFD prediction of flow, heat and mass transfer in woven spacer-filled channels for membrane processes

2021

Abstract Flow and heat or mass transfer in channels provided with woven spacers made up of mutually orthogonal filaments were studied by Computational Fluid Dynamics. The problem addressed was the combined effect of the parameters that characterize the process: pitch to height ratio P/H (2, 3 and 4), flow attack angle θ (0, 7, 15, 20, 30, 40 and 45°) and Reynolds number Re (from ~1 to ~4000). The Prandtl number was 4.33, representative of water at ~40°C, while the Schmidt number was 600, representative of NaCl solutions. Simulations were performed by the finite volume code Ansys CFX™ 18.1 using very fine grids of ~6 to ~14 million volumes. For Re > ~400, the SST turbulence model was used to…

A 2-D model of electrodialysis stacks including the effects of membrane deformation

2021

Abstract Membrane-based processes have gained a relevant role in many engineering applications. Much effort has been devoted to thoroughly understand the fundamental phenomena behind them. However, membrane deformation has been taken into consideration only recently, although much evidence has shown its impacts in many applications. This work presents a novel 2-D, multi-scale, semi-empirical process model able to predict the behavior and the performance of Electrodialysis (ED) systems in cross-flow configurations in the presence and absence of local membrane deformations. The model exploits the results and the simulation approaches of previous fluid-structure investigations performed by the…

Icone. Tradizione/Contemporaneità. Le icone post-bizantine della Sicilia nord-occidentale e la loro interpretazione contemporanea

2019

Si tratta del catalogo della mostra allestita presso il Museo Diocesano di Monreale (PA), nella quale si espongono tredici icone antiche di scuola veneto-cretese dell'Eparchia di Piana degli Albanesi e dello stesso museo (16th-17th secolo), messe a confronto con 12 opere create appositamente da artisti contemporanei , dei quali sei siciliani e sei greci This is the catalogue of the exhibition held at the Museo Diocesano in Monreale (PA), in which thirteen ancient icons of the Venetian-Cretan school of the Eparchy of Piana degli Albanesi and the museum itself (16th-17th century) are exhibited, compared with 12 works specially created by contemporary artists, including six Sicilians and six G…

Arte per Theodoùli. Pittori e committenti di icone post-bizantine della Sicilia occidentale

2019

Il saggio approfondisce le generalità di pittori e committenti di alcune icone post-bizantine della Sicilia nord-occidentale, accomunati dalla definizione di theodoùli, cioè servi di Dio The chapter explores the generality of painters and clients of some post-Byzantine icons of north-western Sicily, united by the definition of theodoùli, i.e. servants of God

Il bosco in aree interne. Risorsa locale o paesaggio ludico?

2021

Per ragionare sulle dendrolatrie - le pratiche, i miti e le figure dell’immaginario arboreo - in prospettiva geografica, questo contributo sviluppa una riflessione sul bosco: figura dell’immaginario arboreo, ma anche risorsa fondamentale per territori rurali e montani. Si analizza in che modo questa risorsa sia interpretata nel contesto delle aree interne: territori gravati da deficit di sviluppo e servizi per i quali dal 2013 la Strategia Nazionale per le Aree Interne (SNAI) ha avviato interventi per adeguare i servizi e promuovere progetti di sviluppo. Si indagano diverse interpretazioni del bosco: dall'approccio conservazionista, a quello della prospettiva territorialista che considera i…

A spectroscopic method for determining lignin content of softwood and hardwood kraft pulps

1998

Abstract A rapid method for determining the kappa number of unbleached and oxygen-delignified kraft pulps in the range 3–35 is presented. This novel method was based on the multivariate analysis of VIS spectral data on pulp samples. The calculated models and the test results indicated that partial least squares (PLS) and principal component regression (PCR) models yielded similar results, PLS being slightly more accurate. It was also found that for practical purposes a separate model for each wood feedstock and delignification process is needed.

Estimation of pulp yield in industrial oxygen-alkali delignification of softwood kraft pulp

2002

Fate of Oxygen in Industrial Oxygen-Alkali Delignification of Softwood Kraft Pulp

2004

Fast-growing willow (Salix viminalis) as a filler in polyethylene composites

2018

Abstract The study investigated the possibility of using wood flour obtained from fast-growing willow chips (Salix viminalis) as an alternative for standard hard- and softwood flours used in the production of wood polymer composites (WPCs). The composites contained willow flour and polyethylene matrix (OPCs) were prepared, characterized and compared with other WPCs which had been filled with hard- or softwood flours. Moreover, the structural and functional properties were investigated and discussed. Greater hemicellulose contents and lower lignin contents in OPCs resulted in better impact strength values of those materials. Which is interesting, the chemical composition of OPCs was found si…

Evaluating pulp stiffness from fibre bundles by ultrasound

2012

A non-destructive ultrasonic tester was developed to measure the stiffness of pulp bundles. The mechanical properties of pulp are important when estimating the behaviour of paper under stress. Currently available pulp tests are tedious and alter the fibres structurally and mechanically. The developed tester employs (933 ± 15) kHz tweezer-like ultrasonic transducers and time-of-flight measurement through (9.0 ± 2.5) mm long and (0.8 ± 0.1) mm thick fibre bundles kept at (19.1 ± 0.4) °C and (62 ± 1)% RH. We determined the stiffness of soft wood pulps produced by three kraft pulping modifications: standard kraft pulp, (5.2 ± 0.4) GPa, prehydrolysis kraft pulp, (4.3 ± 0.4) GPa, and alkali extra…