3D Printing of Wood-Sodium Silicate Composites

Additive manufacturing (AM) for construction applications has grown rapidly over the past 10 years. AM, also referred to as 3D printing, in construction has primarily been done with concrete as a medium up to this point. AM has the ability to rapidly manufacture complex geometry not possible with conventional building techniques. Additionally, AM has the ability to use recycled materials and produces very little waste. Wood-based composites have yet to be used in AM for the construction industry because a method to produce high strength wood-based composites in AM has not been developed. This study details the development of an AM method for wood-sodium silicate composites (WSSC). A 3D printer was designed and constructed utilizing a screw extruder for wood-based composites capable of extruding wood-based composites and depositing them layer by layer onto the printer’s bed. The printer is designed to use a feedstock material of wood flour and a thermoset resin binder. The samples were printed at various wood to resin ratios and were cured at various temperatures. The WSSC’s adhesion to the print bed was assessed in addition to the interlayer adhesion of the printed WSSC during extrusion and after curing. A panel was successfully constructed with wood element size less than 40 mesh, at a 45:55 wood to sodium silicate weight ratio and cured for two days at 60°C. When stressed in bending, the bond between panel layers did not fail, rather failure occurred in the base material. The failures happening away from the boundary layers are consistent with other manufactured wood composites. Thus, AM can be a suitable manufacturing technique for wood-based composites based on the interlayer adhesion.masters, M.S., Mechanical Engineering -- University of Idaho - College of Graduate Studies, 2022-0

Carcinoma de células escamosas perineal em cabras no Pará Perineal squamous cell carcinoma in goats in the State of Pará, Brazil

Descreve-se a ocorrência de carcinoma de células escamosas (CCE) bem diferenciado em caprinos de duas propriedades no Estado do Pará. Foram observadas a prevalência, a correlação com a pigmentação da região perineal e as características macro e microscópica das lesões. As lesões consistiram em tumores no períneo, com grau de desenvolvimento, diâmetro e forma variados. Em uma propriedade no município de Viseu, dos 347 caprinos, 20 apresentaram CCE (5,8%). A neoplasia só foi observada em animais com a região perineal despigmentada. Em outra propriedade, no município de Garrafão do Norte, descreve-se a ocorrência de três casos em um rebanho de 400 caprinos (0,75%). A elevada ocorrência deste tumor deve-se, provavelmente, à despigmentação do períneo e à cauda curta e elevada das cabras, que expõe a região perineal à alta incidência de radiação ultravioleta naquela região.<br>Squamous cell carcinoma in goats of two farms in the State of Pará is described. Prevalence, correlation with the pigmentation of the perineal area and macro and microscopic characteristics of the lesions were studied. The tumors on the perineum were of varied development degrees, diameters and forms. On one farm, in the county of Viseu, from a total of 347 goats, 20 presented the neoplasia (5.8%). On the second farm, in the county of Garrafão do Norte, three cases of squamous cell carcinoma in a herd of 400 goats (0.75%) were observed. The tumor was only observed in animals in which the perineal area was despigmented. The high incidence of this tumor appears to be due to lack of pigmentation at the períneo and the high and short tail of the goats, that exposes the area to intense ultraviolet radiation in the tropics