EVALUATION OF ADHESIVES BASED ON TANNINS FROM Pinus caribaea var. bahamensis AND Acacia mearnsii IN THE MANUFACTURE OF PARTICLEBOARD

Este trabalho teve por objetivo avaliar os m\ue9todos para a extra\ue7\ue3o dos taninos da casca do Pinus caribaea var. bahamensis, assim como verificar a viabilidade t\ue9cnica de utiliza\ue7\ue3o dos taninos da casca de Pinus caribaea var. bahamensis, de Acacia mearnsii , de misturas de taninos de ac\ue1cia negra e pinus e de misturas do adesivo ureia-formalde\ueddo (UF) com taninos de ac\ue1cia e pinus na produ\ue7\ue3o de adesivos para aglomerados. As cascas de Pinus caribaea var. bahamensis foram fragmentadas em moinho de martelo, peneiradas, extra\ueddas sob refluxo, por 2 horas, utilizada uma rela\ue7\ue3o casca:licor de 1:15 p:v, em nove tratamentos. A melhor forma de extra\ue7\ue3o foi utilizada para obten\ue7\ue3o de grandes quantidades de extratos, que foram utilizados na confec\ue7\ue3o de adesivos t\ue2nicos e nas misturas com adesivo UF e com taninos comerciais de ac\ue1cia negra na fabrica\ue7\ue3o de pain\ue9is aglomerados. A adi\ue7\ue3o de sulfito de s\uf3dio proporcionou maior extra\ue7\ue3o de taninos, sendo recomend\ue1vel a extra\ue7\ue3o com adi\ue7\ue3o de 5% de sulfito de s\uf3dio. Os resultados mostraram que tanto os taninos de ac\ue1cia, quanto os de Pinus caribaea var. bahamensis, apresentam boas propriedades de colagem. \uc9 poss\uedvel a adi\ue7\ue3o de solu\ue7\ue3o t\ue2nica de pinus \ue0 solu\ue7\ue3o t\ue2nica de ac\ue1cia e tamb\ue9m substituir parte do adesivo UF pelos taninos de ac\ue1cia em at\ue9 25% sem comprometer a qualidade da colagem. A substitui\ue7\ue3o de 10% de UF por extrato t\ue2nico, tanto de pinus quanto de ac\ue1cia, n\ue3o alterou os valores de inchamento em espessura (IE) dos pain\ue9is. \uc9 poss\uedvel obter boas propriedades mec\ue2nicas com adesivos UF modificados com extratos t\ue2nicos na propor\ue7\ue3o de 10%. Os altos valores encontrados para liga\ue7\ue3o interna (LI) dos pain\ue9is fabricados com extratos t\ue2nicos evidenciaram o potencial desses taninos para colagem de pain\ue9is de madeira.This work aimed to evaluate the methods for extraction of tannin from the bark of Pinus caribaea var. bahamensis, as well as to evaluate the technical feasibility of using tannins from the barks of Pinus caribaea var. bahamensis, of Acacia mearnsii , the mixtures of black wattle and pine tannins and the mixture of adhesive urea formaldehyde (UF) with black wattle and pine tannins in the production of adhesives for particleboard. The barks of Pinus caribaea var. bahamensis were fragmented in hammer mill, sieved and extracted under reflux for 2 hours, using a bark: liquor relation of 1:15, in nine treatments. The best extraction was used to obtain large quantities of extracts, which were used in the manufacture of adhesives and mixtures with UF adhesive and tannins of black wattle and the manufacture of particleboard. The addition of sodium sulfite gave higher extraction of tannin, which was extracted with the addition of 5% sodium sulfite. The results showed that both the black wattle tannin, as the bark of Pinus caribaea var. bahamensis have good bonding properties. It is possible to add pine tannin solution to the solution of black wattle and to replace part of the UF adhesive for the wattle tannins up to 25%, without compromising the glue quality. Replacing 10% of UF for tannic extract, both pine and black wattle, did not alter the values of thickness swelling (TS) of the panels. It is possible to obtain good mechanical properties with UF adhesives modified with tannic extracts at a ratio of 10%. The high values found for the internal bond (IB) panels containing tannin extracts showed the potential of these tannic extracts for bonding wood materials

Snap evaporation of droplets on smooth topographies

Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a “stick-slip” sequence—a combination of pinning and de-pinning events dominated by static friction or “pinning”, caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications

Fast, scalable, Bayesian spike identification for multi-electrode arrays

We present an algorithm to identify individual neural spikes observed on high-density multi-electrode arrays (MEAs). Our method can distinguish large numbers of distinct neural units, even when spikes overlap, and accounts for intrinsic variability of spikes from each unit. As MEAs grow larger, it is important to find spike-identification methods that are scalable, that is, the computational cost of spike fitting should scale well with the number of units observed. Our algorithm accomplishes this goal, and is fast, because it exploits the spatial locality of each unit and the basic biophysics of extracellular signal propagation. Human intervention is minimized and streamlined via a graphical interface. We illustrate our method on data from a mammalian retina preparation and document its performance on simulated data consisting of spikes added to experimentally measured background noise. The algorithm is highly accurate

Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD