Simulação da varredura da superfície por um cortador de base segmentado

Base cutting and feeding into harvesters of plants lying close to the ground surface require an efficient sweeping action of the cutting mechanism. It is not the case of conventional sugarcane harvesters which have rigid blades mounted on discs capable to contaminate the cane with dirt as well as damage the ratoons. The objective of this work was to simulate the sweeping performance of a segmented base cutter. The model was developed using the laws of dynamic. Simulation included two rotational speeds (400 and 600 rpm), two cutting heights (0.12 and 0.13 m) and two disk tilting angles (-10º and -12º). The simulated sweeping angle varied between 56º and 193º, which are very promising as a mean to cutting and feeding cane sticks lying on the ground. Cutting height was the variable that affected sweeping action the most. This behavior indicates the need to have an automatic control of the cutting disk height in order to keep good sweeping performance as the harvester moves forward.

Durabilidade de compósito biomassa vegetal-cimento modificado por polímero

The durability of the cellulose-cement composites is a decisive factor to introduce such material in the market. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work was the physical and mechanical characterization of cellulose-cement composites modified by a polymer and the subsequent durability evaluation. The work also evaluated the dispersion of acrylic polymer in composites made of Pinus caribaea residues. The physical properties observed were water absorption by immersion and bulk density. Rupture modulus and toughness were determined by flexural test. The specimens were obtained from pads, produced by pressing and wet curing. Samples were subjected to accelerated aging tests by repeated wetting and drying cycles and hot-water bath and natural aging. The scanning electron microscopy (SEM) allowed verifying the fiber and composite characteristics along the time. For the composite range analyzed, it was observed the polymer improved the mechanical properties of composites besides a significant decreasing in water absorption. The use of polymer improved the performance of vegetable fiber-cement composites when compared to the conventional mortar, due to water absorption decreasing.

Taxonomic value of foliar characters in Dahlstedtia Malme: Leguminosae, Papilionoideae, Millettieae

Dahlstedtia Malme (Leguminosae) is a neotropical genus, native to the Brazilian Atlantic Forest, and comprises two species, D. pinnata (Benth.) Malme and D. pentaphylla (Taub.) Burk., although it has been considered a monotypic genus by some authors. Leaf anatomy was compared to verify the presence of anatomical characters to help delimit species. Foliar primordium, leaflet, petiolule, petiole and pulvinus were collected from cultivated plants (Campinas, SP, Brazil) and from natural populations (Picinguaba, Ubatuba and Caraguatatuba, SP, Brazil - D. pinnata; Antonina, PR, Brazil - D. pentaphylla). Studies on leaflet surface assessment (Scanning Electron Microscopy), as well as histology and venation analyses were carried out of dehydrated, fresh and fixed material from two species. Leaflet material was macerated for stomatal counts. Histological sections, obtained by free-hand cut or microtome, were stained with Toluidine Blue, Safranin/Alcian Blue, Ferric Chloride, Acid Phloroglucin. Secretory cavities are present in the lamina, petiolule, petiole, pulvinus and leaf primordium in D. pentaphylla, but not in D. pinnata, and can be considered an important character for species diagnosis. Other leaf characters were uninformative in delimiting Dahlstedtia species. There is cambial activity in the petiolule, petiole and pulvinus. This study, associated with other available data, supports the recognition of two species in Dahlstedtia.

Caracterização morfoanatômica e histoquímica de Cuphea carthagenensis (Jacq.) J.f. Macbr. (Lythraceae)

Cuphea carthagenensis (Jacq.) J.F. Macbr. is an herb, which occurs preferably in wet places. Amongst other species of the genus, C. carthagenensis is distinguished for its great chemical potential and frequent use in popular medicine. In this study the morphological and anatomical structures were identified, as well as the histochemical characterization was done. Samples of root, stem and leaves were collected from adult plants. This material was processed for anatomical and histochemical analysis in light microscopy and for morphological analysis, in scanning electron microscopy. Important morphological and anatomical considerations were added for C. carthagenensis, such as: the occurrence of aerenchymatous phellem with suberized layers; the types of trichomes present in the vegetative organs, the characterization of secretory trichomes, as well as the secreted substances. The groups of secondary metabolites presents in the root, stem and leaf of C. carthagenensis with more intense histochemical reaction were: proanthocyanidins, phenolic compounds, acids polysaccharides (mucilage especially) and lipids.

Microencapsulação de óleo essencial de laranja

It was done microencapsulation of natural essencial orange oil through spray-drying. The purpose was to use the best proportion of wall materials among maltodextrin, acacia gum, and modified starch (capsul) in order to retain greater amount of orange oil. The orange oil (10%) and maltodextrin (36%) remained constant. Three spray drying temperatures were employed: 180°C, 200°C and 220°C, therefore, nine final products were obtained. The superficial and inner oil concentrations were measured. The microcapsules were also examined through optical and scanning electron microscopy. The three temperatures employed did not affect the microencapsulation. The microstructure of the capsules were almost similar regardless the proportion employed among the carbohydrates to wall composition. At light microscopy it was observed a great heterogeneity of capsules diameters, and probably not smooth surfaces; at scanning electron microscopy it was clear that the walls displayed porosity over round surfaces. The best retention was given by the formula containing 10% of capsul, 10% of orange oil and 36% of maltodextrin, when total oil retention was 94%, regardless the drying temperature here employed.

Influência da redução medicamentosa da pressão intra-ocular na medida da espessura da camada de fibras nervosas da retina de olhos hipertensos e glaucomatosos pela polarimetria de varredura a laser

PURPOSE: To evaluate changes in retinal nerve fiber layer thickness as measured by scanning laser polarimetry (SLP) after the use of medication to reduce intraocular pressure (IOP) in glaucomatous or ocular hypertensive patients. METHODS: The authors prospectively enrolled 37 eyes of 37 patients in whom IOP was reduced by more than 25% after the use of medication. The images were obtained before and 15 to 30 days after the introduction of medication. The SLP parameters measured before and after the use of medication were compared using paired Student's t Test. RESULTS: The mean IOP was significantly reduced from 26.57±4.23 mmHg to 16.54 ±2.92 mmHg after the use of medication (p<0.05). None of the 10 SLP analyzed parameters was significantly affected by the reduction of IOP with medication (p>0.05). CONCLUSION: The retinal nerve fiber layer thickness, as measured by SLP, is not affected by the reduction of IOP with medication in patients with glaucoma or ocular hypertension.