The Influence of Hot Water Extraction on Physical and Mechanical Properties of OSB

The finite reserves of petroleum are driving renewed interest in technologies that allow for sustainable production of energy. There are a wide variety of technologies with well-developed infrastructure like the oriented strand board (OSB) industry, which could be used as launch point for developing biorefineries. The effects of hot water extraction (HWE) on two hardwood species (Acer rubrum, Populus tremuloides) and softwood species (mixture of southern yellow pine, Tsuga canadensis) were studied. The HWE resulted in a weight loss (WL) that increased as the severity factor (SF) was extended. Hardwood had the biggest WL values at equivalent extraction conditions. The extract contained a mixture of primarily hemicelluloses with some acetic acid and lignin. Select volatile organic compounds from the hot pressing of OSB panels were reduced by HWE of the strands. A clear advantage with extracted OSB panel (softwood or hardwood) for structural use is the improved dimensional stability and physical properties obtained as SF was increased. The mechanical property (MP) of composite for softwood was enhanced while for hardwood was reduced. Substantial improvements in MP were obtained at the intermediate SF (12% WL). When SF was extended beyond the optimum MP declined as measured by a cell wall test in both species. These changes are hypothesized to due to an increase in the percent crystallinity of cellulose. The increase in crystallinity was correlated to the MP, but the effect was less than of SF. Mechanical response was also affected by chemical component changes, micro- buckling, the reduction in moisture content and the reduction adhesion properties. Dispersive surface energy of red maple increased with SF due to extractive removal while that the contact angle measurement showed rapid penetration of probe liquids due to increases of porosity as a result of mass removal at high extraction conditions (over 15% WL). Basic characteristic related by IGC measurements could directly affect the chemical reaction between the resin and wood elements of hardwood species. For all these reasons, the recommended extraction for softwood should be below 12% WL and an improvement of resin system for hardwood species. The ability to manufacture lower density panels with same size and mechanical properties appears feasible to compensate for the material extracted

Decay Resistance Properties of Hot Water Extracted Oriented Strandboard

The use of extracted wood hemicelluloses as a substrate for fermentation and biofuels production has the added benefit of leaving the remaining wood product intact after extraction and being usable in other applications. However, it is still unclear how these extraction procedures might affect susceptibility to fungal attack. Modified oriented strandboards (OSB) were created by hot water extracting red maple strands before adhesive application and pressing of the strands into boards. Treated and untreated boards were tested for decay susceptibility in a modified ASTM soil block jar bioassay using multiple species of white and brown rot fungi. Results showed no significant differences in decay susceptibility between the untreated and extracted boards for all the brown rot fungi tested. The white rot fungi tested were shown to decay the boards made from extracted strands significantly less than the boards made from control strands. These results indicate that modifying OSB panels by removing hemicelluloses for use in ethanol and other alternative fuel production does not increase decay susceptibility to the brown rot fungi tested and appears to confer a degree of decay resistance against the white rot fungi

Selected Volatile Organic Compound Emissions and Performance of Oriented Strandboard from Extracted Southern Pine

The impact of a hot water extraction procedure on select volatile organic compound emissions during pressing, as well as on properties of oriented strandboard (OSB) was evaluated. Southern pine strands were extracted with hot water using a rotating digester at 160°C for 22.9 or 53.6 min. Weight loss for the two extraction conditions was 6.3 ± 0.1% (short time) and 9.3 ± 0.9% (long time). The extract contained a mixture of hemicelluloses, acetic acid, and lignin. OSB panels were manufactured both with and without adhesive. The emissions (phenol, methanol, acetaldehyde, and formaldehyde) without adhesive present decreased from 38.2 to 24.2 mg/kg (oven-dry wood) as a result of the high severity factor (HSF) extraction. When adhesive was used, emissions totaled 22.1, 17.0, and 15.6 mg/kg (oven-dry wood) for control, low severity factor, and HSF, respectively. Water sorption and thickness swell were significantly reduced in panels made from extracted strands. Flexural modulus of elasticity of extracted panels exhibited significant increases in both dry and wet conditions. The flexural modulus of rupture and internal bond were slightly reduced in the dry condition as weight loss increased. The extraction procedure shows promise for improving a variety of properties of OSB, including performance, reduced environmental impact, and generation of a valuable chemical feedstock byproduct

Surface Characterization of Red Maple Strands After Hot Water Extraction

The conversion of carbohydrates from wood to make biofuels such as ethanol is a topic of widespread interest. A promising approach is the removal of the hemicellulosic wood component by extraction with subsequent conversion to biofuels while continuing to produce forest products. The impact of extraction on wood strands for use in strand-based composites was investigated. One tree of red maple (Acer rubrum L.) was used to create strands 10.2 cm long with a thickness of 0.9 mm. Three hot water extraction procedures at 160°C, corresponding to severity factors (SF) of 2.71, 3.54, and 3.81, were used resulting in an average weight loss of 5.7, 16.9 and 18.1%, respectively. Scanning electron microscopic imaging of selected wood strands showed that pores in the cell wall increased as SF increased. The distribution and size of the cell-wall pore structure showed up to a 22.2% increase. The sessile drop method, using distilled water, diiodomethane, and ethylene glycol, indicated more pronounced liquid wetting and penetration as SF increased. Inverse gas chromatography led to the finding that dispersive surface-free energy and acid-base characteristics increase with SF. The extraction procedures should be kept below a SF of 3.54 to minimize changes in adhesion performance

Enhancing dimensional stability of oriented strand composites within biorefinery

The objective of this study was to investigate the effects of hot water extraction process on the dimensional stability of oriented strand composites. Aspen wood strands were extracted using various severity factor levels. Phenol formaldehyde and polymethylene diphenyl diisocyanate resins were used for production of the oriented strandboard panels. Six panel groups were produced from the extracted or unextracted aspen wood strands. The dimensional stability of the material was evaluated by measures of equilibrium moisture content and thickness swell and water absorption after soaking in water for 2 hours and 24 hours. Results obtained in this study showed that thickness swell and water absorption values significantly decreased with the hot water extraction process, with the thickness swell of phenol formaldehyde bonded panels decreasing 70% after 2 hours soaking. The panels with polymethylene diphenyl diisocyanate resin exhibited lower thickness swell and water absorption relative to the panels prepared with phenol formaldehyde resin. Equilibrium moisture content values of the panels bonded with both phenol formaldehyde and polymethylene diphenyl diisocyanate resin decreased with the extraction process. The findings of this work indicate that hot water extraction process could be effectively used to produce oriented strand composites having an enhanced dimensional stability property

Photovoltaic Glass Waste Recycling in the Development of Glass Substrates for Photovoltaic Applications

Because of the increasing demand for photovoltaic energy and the generation of end-of-life photovoltaic waste forecast, the feasibility to produce glass substrates for photovoltaic application by recycling photovoltaic glass waste (PVWG) material was analyzed. PVWG was recovered from photovoltaic house roof panels for developing windows glass substrates; PVWG was used as the main material mixed with other industrial waste materials (wSG). The glass was casted by air quenching, annealed, and polished to obtain transparent substrates samples. Fluorine-doped tin oxide (FTO) was deposited as back contact on the glass substrates by spray pyrolysis. The chemical composition of the glass materials was evaluated by X-ray fluorescence (XRF), the thermal stability was measured by differential thermal analysis (DTA) and the transmittance was determined by UV-VIS spectroscopy. The surface of the glass substrates and the deposited FTO were observed by scanning electron microscopy (SEM), the amorphous or crystalline state of the specimens were determined by X-ray diffraction (XRD) and the sheet resistance was evaluated by the four-point probe method. The sheet resistance of the deposited FTO on the wSG substrate was 7.84 ± 3.11 Ω/, lower than that deposited on commercial soda-lime glass (8.48 ± 3.67 Ω/), meaning that this material could present improved conduction of the produced electrons by the photovoltaic effect. This process may represent an alternative to produce glass substrates from waste materials that could be destined for photovoltaic applications, especially the production of ecological photovoltaic windows

Prospección geológica minera del ANAP Pampa Grande. Informe final

El Instituto Geológico Minero y Metalúrgico (INGEMMET) a través de su dirección de Recursos Mineros y Energéticos, actividad ANAP´s, realizó la evaluación Geológico Minero del ANAP Pampa Grande; los trabajos de campo fueron encargados a los suscritos, con fines de corroborar los hallazgos realizados en anteriores trabajos, muestreos geoquímicos de “stream sediment” “rock chip” y cartografiado geológico entre otros estudios, llevados a cabo por INGEMMET en el cuadrángulo de Cajabamba 16 g; los cuales reportan valores anómalos de Zn, Mo, As y Hg así como definir la naturaleza de las ocurrencias minerales relacionadas a estos elementos metálicos dentro de la zona del ANAP Pampa Grande. Las actividades de prospección se realizaron durante los meses de abril a octubre del 2014, y se retomaron los trabajos prospectivos durante los meses de abril y mayo del 2015 enfocándose principalmente en el reconocimiento, revisión de anomalías geoquímicas y espectrales en una primera instancia; para luego continuar con los trabajos de cartografiado geológico, de alteraciones hidrotermales, muestro geoquímico de rocas, sedimentos de corriente y agua, así mismo se llevaron a cabos los trabajos de prospección geofísica magnetometría y polarización inducida (IP). El ANAP está ubicado en la región de La Libertad, provincias de Otuzco, distritos de Agallpampa y Usquil. Tiene un área de 8,700 has con altura promedio de 4100 m.s.n.m. El ANAP Pampa Grande está dentro de la franja metalogenética XXI donde se hallan múltiples ocurrencias mineras como la mina Lagunas Norte, Alto Chicama (Barrick Gold Corporation); la mina Comarsa (Compañía Minera Aurífera Santa Rosa S.A.); la mina La Virgen (Compañía Minera San Simón S.A.) y la Mina Quiruvilca; también están los proyectos de oro y plata Caupar (S.A.C Sociedad Minera Trinity Perú SAC), Shahuindo (Sulliden Exploration Inc.); Tres Cruces (New Oroperu Resources Inc.) y La Arena (Río Alto Mining Limited). El marco geológico regional del ANAP, está conformado por rocas sedimentarias del Cretácico (Grupo Goyllarisquizga) y volcánicas de edad Oligomiocénico (Grupo Calipuy). El principal control estructural regional lo constituye el sistema de fallas Pallasca–Cordillera Blanca de orientación NO-SE; relacionado a este corredor estructural, se encuentran 03 lineamientos que se disponen en forma paralela; estos son: de norte a sur, Dos de Mayo-Barro Negro-Tambo de dirección N310°, Payhual – San Apolonio de dirección N 300°-310° y Otuzco-Quirúvilca-Tres Cruces de sentido N300°-305°. Se recolectaron un total de 337 muestras, en las campañas de campo realizadas por INGEMMET durante el 2014 y 2015; 307 muestras de rocas primarias con 30 muestras de control lo que equivale al 9.5% QA/QC; además 24 muestras de sedimento de corriente distribuidas en 20 muestras primarias 2 blancos 1 estándar y 1 duplicado. En este ANAP se han reconocido dos targets nominados como ANOMALÍA ULLAPCHAM, esta consiste de afloramientos discontinuos de un lithocap silíceo o litocapa silícea, cuerpo de sílice mantiforme con textura bandeada a coloforme de sílice opalina a calcedonica; con goethita, hematita, jarosita y diseminaciones de pirita, en algunos sectores se puede observar estructuras anulares de sílice porosa a oquerosa con óxidos, que estaría relacionada a conductos de escape de gases; en algunos lugares se observa la textura "patchy" definida por parches de caolín-illita ameboidea que se encuentran en rocas silicificadas, que nos sitúa en la parte media a inferior de la litocapa, como por ejemplo en los yacimientos de La Escondida y Yanachocha. La proximidad al pórfido de cobre se puede deducir por la firma geoquímica con anomalías de molibdeno y arsénico además la presencia de calcopirita en trazas muestra PG14-112, nos hace pensar en la proximidad al sistema tipo pórfido de cobre-, sus dimensiones son 1.7 por 0.15 km su espesor esta entre 0.5 a 1m y pueden alcanzar los 2m; su rumbo varía entre N 300° a 290° y su inclinación es de 20° NE; cubren un área de unos 2.5 km. Presentan anomalías geoquímicas de rocas en Mo (> 10ppm), As (> 10ppm) las que circunscriben una anomalía de 650 x 100 m de rumbo N35° para el Mo>10 ppm y otra de 220 x 40 m de dirección N40° para el Mo>25 ppm. ANOMALÍA SAN APOLONIO, constituida por venillas irregulares tipo network de sílice gris con óxidos; anchos promedio 02 centímetros con direcciones de N50° a 60° N70° a 80°, N20° a 30° y N300° a 310°, estas estructuras se han desarrollado en andesitas de color gris blanquecino de textura porfirítica con fenocristales de plagioclasas tiene una alteración tipo sílice–argílica; sus dimensiones son: 1,5 km de largo por 0,3 km de ancho tiene una dirección de N60°. Además se han reconocido dos estructuras discontinuas de brechas hidrotermales polimícticas matriz soportada conformada por sílice y arcillas blancas 20% y cuyo cemento es sílice y óxidos, sus fragmentos son de 70% cuarcitas con diseminaciones y venillas irregulares de óxidos, 20% andesitas porfíricas gris rojizas y 10% andesitas porfiríticas con fenocristales de plagioclasas con alteración de sílice ARCs blancas, de forma subangulosa a subredondeada cuyos diámetros de estos clastos son mayores 13 a 10 cm, en promedio es 4 cm y menores 0,5 cm además se observa venillas irregulares de sílice gris con óxidos de anchos centimétricos, de rumbo N65°/35°SE ancho 1,0 m. y de extensión de afloramiento 4 m. Por su parte la segunda estructura de brecha su dirección varia N40°/60°NW ancho 0,80 m. y de corrida de afloramiento de 3 m. Reporta valores anómalos para el Zn (> 100 ppm) y Hg (> 1 ppm), que delimitan una superficie de 1,5 km de largo por 0,3 km de dirección de N60°. En ambos sectores no se reportan valores anómalos de Au ni Ag

Oxigenación con membrana extracorpórea en el paciente COVID-19: resultados del Registro Español ECMO-COVID de la Sociedad Española de Cirugía Cardiovascular y Endovascular (SECCE)

Background and aim: COVID-19 patients with severe heart or respiratory failure are potential candidates for extracorporeal membrane oxygenation (ECMO). Indications and management of these patients are unclear. Our aim is to describe the results of a prospective registry of COVID-19 patients treated with ECMO. Methods: An anonymous prospective registry of COVID-19 patients treated with veno-arterial (V-A) or veno-venous (V-V) ECMO was created on march 2020. Clinical, analytical and respiratory preimplantation variables, implantation data and post-implantation course data were recorded. The primary endpoint was all cause in-hospital mortality. Secondary events were functional recovery and the combined endpoint of mortality and functional recovery in patients followed at least 3 months after discharge. Results: Three hundred and sixty-six patients from 25 hospitals were analyzed, 347 V-V ECMO and 18 V-A ECMO patients (mean age 52.7 and 49.5 years respectively). Patients with V-V ECMO were more obese, had less frequently organ damage other than respiratory failure and needed less inotropic support; Thirty three percent of V-A ECMO and 34.9% of V-A ECMO were discharged (P = NS). Hospital mortality was non-significantly different, 56.2% versus 50.9% respectively, mainly during ECMO therapy and mostly due to multiorgan failure. Other 51 patients (14%) remained admitted. Mean follow-up was 196 +/- 101.7 days (95%CI: 170.8-221.6). After logistic regression, body weight (OR 0.967, 95%CI: 0.95-0.99, P = 0.004) and ECMO implantation in the own centre (OR 0.48, 95%CI: 0.27-0.88, P = 0.018) were protective for hospital mortality. Age (OR 1.063, 95%CI: 1.005-1.12, P = 0.032), arterial hypertension (3.593, 95%CI: 1.06-12.19, P = 0.04) and global (2.44, 95%CI: 0.27-0.88, P = 0.019), digestive (OR 4,23, 95%CI: 1.27-14.07, P = 0.019) and neurological (OR 4.66, 95%CI: 1.39-15.62, P = 0.013) complications during ECMO therapy were independent predictors of primary endpoint occurrence. Only the post-discharge day at follow-up was independent predictor of both secondary endpoints occurrence. Conclusions: Hospital survival of severely ill COVID-19 patients treated with ECMO is near 50%. Age, arterial hypertension and ECMO complications are predictors of hospital mortality, and body weight and implantation in the own centre are protective. Functional recovery is only predicted by the follow-up time after discharge. A more homogeneous management of these patients is warranted for clinical results and future research optimization. (C) 2022 Sociedad Espanola de Cirugia Cardiovascular y Endovascular. Published by Elsevier Espana, S.L.U