Production of reinforced composites with natural fibers for industrial applications - Extrusion and injection WPC

The aim of this work is to study the replacement of currently used thermoplastics by composites reinforced with vegetable fibers with several advantages, mainly better mechanical properties, low weight and competitive cost compared to its counterparts. Extrusion and injection molding processes were studied using polypropylene (PP) matrix. The raw materials used were sugar cane bagasse, elephant grass, wood, milk cartons and recycled polypropylene. The composites were tested for bending, tension, hardness and impact resistance, following ASTM standards. The results obtained were extremely positive since they proved that natural fibers as reinforcement can be an important alternative to replace talc and other fillers.

Soviet active measures : the WPC Copenhagen Peace Congress, October 15-19, 1986.

"July 1986."

Effects of refrigeration, freezing and replacement of milk fat by inulin and whey protein concentrate on texture profile and sensory acceptance of synbiotic guava mousses

The effects of refrigeration, freezing and substitution of milk fat by inulin and whey protein concentrate (WPC) on the texture and sensory features of synbiotic guava mousses supplemented with the probiotic, Lactobacillus acidophilus La-5, and the prebiotic fibre oligofructose, were studied. The frozen storage (-18 +/- 1 degrees C), followed by thawing at 4 degrees C before the analyses, and the complete replacement of the milk fat by inulin plus WPC, led to significant differences in the instrumental texture parameters of mousses (P < 0.05). Nonetheless, these changes did not affect the sensory acceptability of the products studied. The frozen storage may be employed to extend the shelf-life of synbiotic guava mousses. Additionally, to obtain a texture profile similar to the traditional product, the simultaneous addition of inulin and WPC is recommended only for the partial replacement of milk fat in refrigerated and frozen mousses, and the total proportion of both ingredients together should not exceed 2.6%. (C) 2010 Elsevier Ltd. All rights reserved.

Viability of Lactobacillus acidophilus in synbiotic guava mousses and its survival under in vitro simulated gastrointestinal conditions

The effects of refrigeration, freezing and substitution of milk fat by inulin and whey protein concentrate (WPC) on Lactobacillus acidophilus La-5 viability and resistance to gastric and enteric simulated conditions in synbiotic guava mousses effects were investigated. Refrigerated mousses supplemented with WPC presented the best probiotic viability. ranging from 7.77 to 6.24 log cfu/g during 28 days of storage. The highest probiotic populations, above 7.45 log cfu/g, were observed for all frozen mousses during 112 days of storage. Decreased L acidophilus survival during the in vitro gastrointestinal simulation was observed both for refrigerated and frozen mousses. Nonetheless, for the refrigerated mousses, the addition of inulin enhanced the probiotic survival during the in vitro assays in the first week of storage. L acidophilus survival in simulated gastrointestinal fluids was also improved through freezing. The frozen storage may be used to provide increased shelf-life for synbiotic guava mousses. Even though the protective effect of inulin and WPC on the probiotic microorganism tested was shown to be more specific for the refrigerated products, the partial replacement of milk fat by these ingredients may also help, as it improves the nutritional value of mousses in both storage conditions. (C) 2009 Elsevier B.V. All rights reserved.

The Influence of Calcium Chloride on the Setting Time, Solubility, Disintegration, and pH of Mineral Trioxide Aggregate and White Portland Cement with a Radiopacifier

This study evaluated the influence of addition of 10% calcium chloride (CaCl(2)) on the setting time, solubility, disintegration, and pH of white MTA (WMTA) and white Portland cement (WPC). A test of the setting time was performed following the #57 ADA specifications and a test of the final setting time according to the ASTM. For the solubility tests disintegration and pH, Teflon rings were filled with the cements and weighed after setting. After 24 h in a desiccator, they were once again weighed. Thereafter, they were immersed in MiliQ water for 24 and 72 h and 7, 14, and 28 days, with maintenance in the desiccator and weighing between periods. The pH of water in which the rings were immersed was measured immediately after contact with them and in the other periods. The addition of CaCl(2) provided a significant reduction (50%) in the initial setting time of cements. The final setting time of WMTA was reduced in 35.5% and the final setting time of WPC in 68.5%. The WMTA with CaCl(2) absorbed water and gained weight with time, except for in the 24-h period. The addition of CaCl(2) to the WPC reduced its solubility. The addition of CaCl(2) increased the pH of WMTA in the immediate period and at 24 and 72 h and for WPC in the immediate period and at 24 h. The addition of CaCl(2) to WMTA and WPC reduced the setting times and solubility of both and increased the pH of cements in the initial periods. (J Endod 2009;35:550-554)

Availability of folate bound to folate-binding protein: Environmental effects

The effect of FBP on folate bio-availability depends on its environment. The FBP of whole WPC enhances bioavailability of folates more than does purified FBP and its efficacy might be even greater when lipids are removed from the WPC. FBP polymerises and folate release from the polymer is found to be slower than that from the monomer. FBP has a role also as a folate receptor at cell surfaces and in this role folate binding increases polymerisation of FBP attached to lipid membranes.

Lean performance measures in a supply chain

Dissertação para obtenção do Grau de Mestre em Engenharia e Gestão Industrial

Using the GPU to design complex profile extrusion dies

In the present work the benefits of using graphics processing units (GPU) to aid the design of complex geometry profile extrusion dies, are studied. For that purpose, a3Dfinite volume based code that employs unstructured meshes to solve and couple the continuity, momentum and energy conservation equations governing the fluid flow, together with aconstitutive equation, was used. To evaluate the possibility of reducing the calculation time spent on the numerical calculations, the numerical code was parallelized in the GPU, using asimple programing approach without complex memory manipulations. For verificationpurposes, simulations were performed for three benchmark problems: Poiseuille flow, lid-driven cavity flow and flow around acylinder. Subsequently, the code was used on the design of two real life extrusion dies for the production of a medical catheter and a wood plastic composite decking profile. To evaluate the benefits, the results obtained with the GPU parallelized code were compared, in terms of speedup, with a serial implementation of the same code, that traditionally runs on the central processing unit (CPU). The results obtained show that, even with the simple parallelization approach employed, it was possible to obtain a significant reduction of the computation times.

Design and optimization of an extrusion die for the production of wood–plastic composite profiles

In this work, the optimization of an extrusion die designed for the production of a wood–plastic composite (WPC) decking profile is investigated. The optimization was performed with the help of numerical tools, more precisely, by solving the continuity and momentum conservation equations that govern such flow, and aiming to balance properly the flow distribution at the extrusion die flow channel outlet. To capture the rheological behavior of the material, we used a Bird-Carreau model with parameters obtained from a fit to the (shear viscosity versus shearrate) experimental data, collected from rheological tests. To yield a balanced output flow, several numerical runs were performed by adjusting the flow restriction at different regions of the flow-channel parallel zone crosssection. The simulations were compared with the experimental results and an excellent qualitative agreement was obtained, allowing, in this way, to attain a good balancing of the output flow and emphasizing the advantages of using numerical tools to aid the design of profile extrusion dies.

Puukuitulujitteiset muovikomposiitit puunjalostusteollisuudessa

Puukuitulujitteisten muovikomposiittien käyttömäärät ovat maailmanlaajuisesti kasvaneet jatkuvasti viimeisen 15 vuoden aikana.Kasvun on ennustettu jatkuvan voimakkaana myös tulevaisuudessa. Diplomityön tavoitteena oli selvittää puukuitulujitteisten muovikomposiittimateriaalien soveltuvuus erääseen, mahdollisesti rakennusteollisuuden käyttöön tulevaan, tuotteeseen. Tutkittaviksi materiaaliyhdistelmiksi valittiin sekä kerta- että kestomuovin ja puu- jauhon seos. Puujauho oli koivupuista sahaus- ja hiontajätettä. Molemmissa tapauksissa puun osuus komposiitissa oli 30 p-%. Koekappaleiden valmistuksessakäytettiin koivupuisia muotteja, joihin materiaali annosteltiin. Kertamuovin japuujauhon seos kovettui huoneenlämmössä. Kestomuovin ja puujauhon seoksen sulatukseen käytettiin lämmitettävillä puristinlevyillä varustettua aihiopuristinta. Koekappaleille määritettiin taivutuslujuudet taivutuskokeen avulla. Koekappaleiden taivutuslujuuksia verrattiin mm. lattialastulevyn ja koivuliimalevyn arvoihin. Liimalevyn taivutuslujuus muihin verrattuna oli huomattavasti suurempi. Komposiittimateriaalista valmistettujen koekappaleiden taivutuslujuus oli lähellä lattia-lastulevyn tasoa, osittain jonkin verran parempikin. Diplomityössä saatujen tulosten perusteella voidaan todeta puukuitulujitteisilla muovikomposiiteilla olevan kehityspotentiaalia myös tutkimuskohteen tyyppisissä ratkaisuissa. Jatkotutkimusta tulisi kohdistaa ennen kaikkea kestomuovipohjaisen komposiittimateriaalinsuuntaan.

Effects of Surface Properties and Wood Modification into Direct Printing on Wood

Building industry is a high volume branch which could provide prominent markets for wood based interior decoration solutions. Competition in interior decoration markets requires versatility in appearance. Versatility in wood appearance and added value could be achieved by printing grain patterns of different species or images directly onto wood. The problem when planning wood printing’s implementing into durable applications is basically how to transfer a high quality image or print sustainably onto wood, which is porous, heterogeneous, dimensionally unstable, non-white and rough. Wood preservation or treating, and modification can provide durability against degradation but also effect to the surface properties of wood which will effect on printability. Optimal adhesion is essential into print quality, as too high ink absorbance can cause spreading and too low ink absorbance cause pale prints. Different printing techniques have different requirements on materials and production. The direct printing on wood means, that intermedias are not used. Printing techniques with flexible printing plates or in fact non-impact techniques provide the best basis for wood printing. Inkjet printing of wood with different mechanical or chemical surface treatments, and wood plastic composite material gave good results that encourage further studies of the subject. Sanding the wood surface anti-parallel to the grain gave the best overall printing quality. Spreading parallel to the grain could not be avoided totally, except in cases where wood was treated hydrophobic so adhesion of the ink was not sufficient. Grain pattern of the underlying wood stays clearly visible in the printed images. Further studies should be made to fine tune the methods that already gave good results. Also effects of moisture content of wood, different inks, and long-term exposure to UV-radiation should be tested.

ArkWood-case puumuovitalo

Rakennusalalla kehitetään uusia materiaaleja ja rakennuslainsäädäntö muuttuu kiivaaseen tahtiin. Kilpailu alalla kiristyy ja tarvitaan uusia toimintatapoja rakentamisen kaikissa vaiheissa aina suunnittelusta toteutukseen. Puumuovikomposiitti on Suomessa uudehko rakennusmateriaali. Tässä työssä selvitetään tällä hetkellä voimassa olevien rakennusmääräysten ja standardien asettamia vaatimuksia puumuovikomposiittien käytölle rakentamisessa Suomessa sekä kehitetään omaa yritystoimintaa laatimalla oman yrityksen liiketoimintasuunnitelma. Tässä diplomityössä on laadittu puumuovikomposiittitalon rakennuslupapiirustukset ja selvitetty, kuinka Lappeenrannan rakennusvalvonta suhtautuu puumuovikomposiitin käyttöön kyseessä olevassa kohteessa rakennuslupahakemusvaiheessa. Suunnitellusta puumuovitalosta on pyydetty tarjoukset talotoimittajilta ja arvioitu puumuovikomposiitin käytön vaikutusta rakentamisen kokonaiskustannuksiin. Liiketoimintasuunnitelman laadinnassa on hyödynnetty aihealueeseen liittyvää kirjallisuutta ja julkaisuja yhdistäen niihin omia näkemyksiä ja ideoita.

Kytkentäaineet puumuovikomposiiteissa

Puumuovikomposiittien valmistuksessa yhdistetään kaksi toisistaan eroavaa materiaalia jolloin saadaan aikaan materiaalien ominaisuuksien ainutlaatuinen yhdistelmä. Polymeerimateriaaleina käytetään pääasiassa erilaisia kestomuoveja. Kuitumateriaaleina voidaan käyttää puujauhetta, sahanpurua, paperin- ja kartongin valmistuksessa käytettävää sellua, nanoselluloosaa tai muita puukuitumateriaaleja. Polaarisen puukuidun ja polaarittoman muovimateriaalin välinen materiaalien rajapinnan adheesio on yleensä riittämätöntä, mikä vaikuttaa lopputuotteen ominaisuuksien heikkenemiseen. Kyseinen ongelma on pyritty ratkaisemaan käyttämällä erilaisia kytkentäaineita. Tässä työssä keskitytään käsittelemään erilaisia puumuovikomposiittien kytkentäaineita, niiden toimintaa sekä vaikutuksia lopputuotteeseen. Lisäksi työssä esitellään myös puumuovikomposiittien valmistusmateriaaleja ja valmistusprosesseja.

Kaupallisten komposiittituotteiden materiaaliominaisuuksien määritys ja vertailu

Tässä kandidaatintyössä tutkittiin viiden kaupallisen puu-muovikomposiittituotteen säänkestävyyttä kolmen eri materiaaliominaisuuden avulla. Tuotteet olivat Suomessa markkinoilla olevia terassirakentamisen tuotteita ja niiltä mitattiin Charpy -iskulujuutta, veden absorptiokykyä ja värinmuutosta. Tuloksia verrattiin sekä keskenään, että muualla maailmassa tutkittujen kaupallisten tuotteiden kanssa. Tulosten perusteella havaittiin, että Suomen markkinoilla olevien tuotteiden säänkestävyys on erinomainen.