Talita Baldin

AVALIAÇÃO DAS PROPRIEDADES FÍSICO-MECÂNICAS DE PAINÉIS DE CASCA DE ARROZ E ADESIVO TANINO-FORMALDEÍDO

Rice husk, waste produced by processing of rice, has become a problem of environmental, economic and public health. As a result, this research aims to explore the potential of these underutilized resources in Brazil in the development of particleboard glued with tannin-formaldehyde. Therefore, panels were manufactured with rice husk compacted at different density (0.65, 0.95 and 1.15 g/ cm³), levels of adhesives (7, 10 and 13%) and particles types (natural and processed), totaling 54 panels. The pressing was carried in hydraulic press at 30 kgf /cm² for 8 minutes at 180°C of temperature. The physical tests performed were moisture content, density, water absorption and thickness swelling while mechanical properties evaluated were static bending, screw withdrawal and internal bond. In general, the use of rice hulls prouced a reduction in strength when compared to those made with wood particles. All particleboard were below the minimum standards in physical and mechanical properties; only the panels with 13% resin provided minimum values required by market standards regarding dimensional stability. The results indicate that the material cannot be used in conditions requiring great structural efforts.

Anatomia da madeira de Eucalyptus Benthamii Maiden & Cambage, espécie promissora para o setor de celulose no sul do Brasil

E investigada a anatomia microscopica da madeira de exemplares jovens de Eucalyptus benthamii Maiden & Cambage (Myrtaceae – Leptospermoideae) procedentes do estado do Rio Grande do Sul. Destacam-se os seguintes caracteres anatomicos: madeira composta por fibras, raios, parenquima axial e, em menores porcentagens, elementos vasculares e traqueides vasculares; vasos quase sempre solitarios, numerosos, em arranjo diagonal e porosidade difusa; parenquima paratraqueal vasicentrico e confluente; raios unisseriados, homogeneos e heterogeneos; e fibras libriformes. Mesmo sem caracteristicas singulares em sua estrutura, a presenca de elementos vasculares curtos, parenquima paratraqueal e fibras libriformes atestam um carater relativamente evoluido, comparado as Mirtaceas nativas. Apesar de jovens, as amostras analisadas recomendam a utilizacao da madeira de Eucalyptus benthamii para a industria de celulose e papel.

Comportamento espectral de espécies utilizadas em arborização urbana

The aim of this research was to characterize and measure the spectral behavior of six tree species grown at the Federal University of Santa Maria/RS. The studied species were Eucalyptus sp., Ficus benjamina , Inga marginata , Schinus terebinthifolius , Psidium cattleyanum and Handroanthus chrysotrichus . Were randomly collected seven healthy leaves for each specie, andanalyzed with FieldSpec3 Spectroradiometer, in the wavelength range from 350 to 2.500 nm. Were calculated 61 vegetation indices based on the mean average reflectances. Was applied a principal component analysis based on array x species matrice. The differences between the spectral behavior of the species were tested with a variance analysis (Tukey) by each spectral band of the Worldview 2 satellite sensor. The statistical analyses were performed with R software. Hierarchical clustering analysis was performed with PC-ORD 6.0 taking into account the Euclidean distance as measure of dissimilarity. To obtain and process spectral data were used ASD ViewSpecPro 4.05 and SAMS 3.2 softwares. The first component comprehended 90.94% of the variance for the dataset. The lowest ratio between the group and the average differences per specie was in the Red band. The Coastal, Blue, Green, Yellow and Red bands obtained similar behaviors, with differences in the species F. benjamina (except Greens band), I. marginata (Green and Yellow), and P. cattleyanum (Green). The Red Edge band presented no distinction between species. Reflectance differences were more visible in the Near Infrared 1 and 2 bands. Optimized Vegetation Index 1 and Simple Ratio 8 were the most effective indices to study the species.

Tratamentos térmicos e secagem da madeira serrada de uva-do-Japão

The purpose of this study was ascertaining the influence of heat treatments in the drying rate and wood quality of Japanese raisin tree (Hovenia dulcis Thunb.). In order to do so, four trees with 25 years and average diameter at breast height of 39.5 cm and an average commercial height of 10 m, were harvested and transformed into samples of 40 x 130 x 500 mm (thickness x width x length), and classified as to the radial and tangential orientation of the material. The treatments consisted of heating in water by 12 and 24 h at 85 oC, and freezing by 12 and 24 h at - 18 oC. Then, the lumber was subjected to drying at 75 °C in a forced convection greenhouse until reach 12% of final moisture content. The freezing and heating treatments have proven to be influential on the drying rate, since the first accelerated the drying process, whereas the other one decreased. The freezing treatment by 24 h with samples oriented in the tangential direction showed higher drying rate compared with the others. The treatments presented to be not significant for the reduction of the contractions in the samples related to width, thickness and length. However, the volumetric contraction was significantly higher in samples heated in water. The Hovenia dulcis wood did not show top or surface cracks in any of the treatments used in this study.

Anatomia da madeira de duas espécies de Mimosa da série Stipellares Benth.

Sao anatomicamente descritos e ilustrados com fotomicrografias os lenhos de Mimosa barnebiana e Mimosa bifurca. O exame da estrutura anatomica de ambas as especies e a comparacao das mesmas com outras da serie Stipellares Benth., constantes na literatura, demonstra que a presenca de poros em numerosos multiplos e em arranjo nitido ou tendente a diagonal (dendritico) e traco comum a todo o grupo e, dentro do genero Mimosa, observado apenas em especies da referida serie botânica.

Anatomia do lenho de Maytenus cassineformis Reissek (Celastraceae)

O presente trabalho tem o objetivo de descrever, microscopicamente, o lenho de Maytenus cassineformis Reissek, arvoreta nativa no Rio Grande do Sul. A descricao do lenho foi realizada com base nas normas da Associacao Internacional de Anatomistas da Madeira (IAWA). Foram observados: vasos predominantemente solitarios e em porosidade difusa; parenquima axial ausente; tecido radial heterogeneo; e fibras septadas e nao-septadas. Os caracteres anatomicos sao compativeis com referencias da literatura para Celastraceae, com pequenas divergencias a nivel de genero.

Descrição anatômica de Calycophyllum Multiflorum Griseb. (Rubiaceae)

O lenho de Calycophyllum multiflorum Griseb. e anatomicamente descrito e ilustrado. A estrutura microscopica e comparada com referencias da literatura, destacando-se: vasos extremamente numerosos, em multiplos radiais, menos comumente solitarios e racemiformes; elementos vasculares de comprimento medio, com apendices longos; parenquima axial ausente; raios heterogeneos, em sua maioria com duas celulas de largura; e fibras libriformes septadas, de paredes delgadas a espessas.

Anatomia da Madeira de Calycophyllum spruceanum (Benth.) K. Schum. E Calycophyllum spruceanum F. Brasiliensis K. Schum.

As madeiras de Calycophyllum spruceanum e C . spruceanum f. brasilisensis sao anatomicamente descritas e ilustradas com fotomicrografias. Ambas compartilham os seguintes caracteres: aneis de crescimento distintos; poros numerosos, em arranjo radial e de paredes espessas; porosidade difusa; placas de perfuracao simples; pontoacoes intervasculares pequenas, ornamentadas; parenquima axial ausente; raios heterocelulares; e fibras libriformes septadas, de comprimento medio, com paredes delgadas a espessas. A estrutura anatomica da madeira inclina-se favoravelmente a proposicao de K. Schumann e Mueller Argoviensis, que consideraram a forma brasiliensis como taxon infraespecifico de Calycophyllum spruceanum .

Anatomia da Madeira de Melia azedarach L. (Meliaceae)

A anatomia da madeira de Melia azedarach L. e descrita de acordo com IAWA (1989) e ilustrada com fotomicrografias, com base em material procedente de Jaguari, RS, Brasil. Na estrutura da madeira destacam-se: poros em multiplos radiais; placas de perfuracao simples; elementos vasculares pequenos; pontoacoes intervasculares pequenas, alternas e ornamentadas; parenquima axial vasicentrico, confluente e marginal; raios homogeneos; e fibras libriformes nao septadas.

Anatomia da madeira de Calycophyllum candidissimum (Vahl) DC. (Rubiceae)

Sao descritos e ilustrados os caracteres microscopicos da madeira de Calycophyllum candidissimum (Vahl)DC., destacando-se: vasos extremamente numerosos, em multiplos radiais, menos comumente solitarios eracemiformes; elementos vasculares de comprimento medio, com apendices longos; parenquima axial ausente;raios heterogeneos, em sua maioria com 3 celulas de largura; e fibras libriformes septadas, de paredesdelgadas a espessas.