The role of sugar cane straw on soil reaction

Conduziram-se dois experimentos em laboratório avaliar o efeito da palha da cana- de-açúcar na acidez do solo. A palha da cana foi adicionada nas doses de 0, 20, 40, e 76 g kg-1 na superfície de um latossolo roxo distrófico acondicionado em colunas de PVC. O solo foi incubado a capacidade de campo durante 0, 7, 14, 45, e 90 dias. Após cada incubação, o solo das colunas foram subdividido e amostrado nas seguintes frações 0-5, 5-10, 10-15, 15-20, e 20-25 cm. Com o aumento da dose da palha da cana verificou-se aumento do pH CaCl2 do solo e decréscimo do alumínio trocável até a camada de 15 cm de solo da coluna de PVC. A contribuição de compostos orgânicos para a destoxificação do Al aumentou com o acréscimo das doses da palha da cana. O crescimento da raiz das plantas trigo usadas como planta indicadora aumentou com o acréscimo das doses da palha de cana. O máximo de crescimento da raiz foi até a camada de 15 cm de solo depois de oito dias para a maior dose de palha da cana-de-açúcar.

EFFECT of METAL PRIMERS on BOND STRENGTH of RESIN CEMENTS TO BASE METALS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal degradation of geomembranes after exposure to heat

HDPE and PVC geomembranes are sensitive to changes in their properties when in contact with high temperatures. The effects of hot temperature on polymeric geomembranes are assessed by the ASTM D794 and ASTM D5721.This paper brings an analysis of degradation of the Poly Vinyl Chloride (PVC) and High Density Poly Ethylene (HDPE) geomembranes when exposed to conventional and air oven after specific periods.. Mechanical and physical properties were evaluated. OIT tests were also performanced to evaluate the level of oxidation degradation occurred on the HDPE geomembranes. Geomembranes of two thicknesses were tested: 1.0, 2.0 nun (PVC) and 0.8, 2.5 mm, (HDPE). The results obtained show, for example, that after the last period of exposure, the PVC geomembranes (1.0, 2.0 mm) were more rigid and stiffer than fresh samples. The HDPE geomembranes, on the other hand, when exposed to heat presented increases in deformation. OIT tests showed efficient to detect some level of degradation on the HDPE geomembranes.

Persistence and effectiveness of pyrethroids in plastic strips against Varroa jacobsoni (Acari : Varroidae) and mite resistance in a mediterranean area

An apiary trial was conducted in 1997 in Sardinia, Italy, to verify the effectiveness of fluvalinate in polyvinyl chloride strips and flumethrin in polyethylene strips against Varroa jacobsoni Oudemans. Two indices to evaluate the efficacy of the treatments were adopted: percentage change in mite infestation of worker-sealed brood cells considering only treated hives and percentage change in mite mortality, and the natural variation in mite populations recorded in control hives during the trial. All acaricide treatments reduced the level of mite infestation of both sealed brood and adult bees. However, their effectiveness was slightly reduced in comparison to previous studies because of mite resistance phenomena. Portions of polyethylene strips of flumethrin from treated hives were sampled weekly to determine acaricide persistence using gas chromatography. After 4 wk, a slight reduction (approximate to9%) of the active ingredient content was observed, A laboratory bioassay also was performed to establish the resistance of adult female mites to fluvalinate, Mites were sampled from the experimental apiary and from various Sardinian apiaries which had primarily been subjected to fluvalinate applications in plastic strips or wood inserts for years. Mite resistance varied from 0 to 96%, depending on the acaricide management adopted, the lowest resistance level occurred in an apiary where pyrethroids had never been used, whereas the highest level occurred in an apiary with intensive use of fluvalinate in wood inserts.

Tratamento térmico na manutenção da qualidade de lichias armazenadas sob refrigeração

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atmosfera modificada e aplicação de cloreto de cálcio em caqui Giombo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O monitoramento dos movimentos corporais do sono e do ritmo de sono-vigília como indicador das alterações provocadas pela asfixia em ratos recém-nascidos

Pós-graduação em Pediatria - FMB

Conservação pós-colheita de mangaba (Hancornia Speciosa Gomes)

Pós-graduação em Agronomia - FEIS

Ability of Salmonella spp. to Produce Biofilm Is Dependent on Temperature and Surface Material

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dispositivo microfluídico de borracha natural (LAB-ON-A-CHIP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biodegradation of films of low density polyethylene (LDPE), poly(hydroxibutyrate-co-valerate) (PHBV), and LDPE/PHBV (70/30) blend with Paecilomyces variotii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso de ácido ascórbico e cloreto de cálcio na qualidade de repolho minimamente processado

The objective of this trial was to evaluate the effect of ascorbic acid (AA) and calcium chloride (CaCl2) applied by immersion at temperatures of 20 and 40 degrees C on the physicochemical and sensory characteristics of minimally processed cabbage, stored under refrigeration. Cabbages were processed in an industrial food processing equipment to be cut in slices with thickness of 3 mm. Slices were immersed in sodium hypochlorite (50 ppm) during 5 minutes for sanitization. After, the following treatments were carried out T1= control (immersion in water during 5 minutes at 20 degrees C); T2= immersion in 1% AA solution, during 5 minutes at 20 degrees C; T3= immersion in 2% AA solution, during 5 minutes at 20 degrees C; T4= immersion in 1% CaCl2 solution during 5 minutes at 20 degrees C; T5= immersion in 2% CaCl2 solution during 5 minutes at 20 degrees C, T6= immersion in 1% CaCl2 solution during 5 minutes at 40 degrees C; and T7= immersion in 2% CaCl2 solution during 5 minutes at 40 degrees C; with four replications each one. After application of treatments, cabbage was centrifuged during one minute, wrapped with polyvinyl chloride, 20 mu m, in trays of expanded polystyrene and maintained in refrigerated environment, at 6 +/- 1 degrees C and 85-90% of relative humidity, during eight days. Little increasing was observed in pH and titratable acidity values and reduction in soluble solids during conservation period on all treatments. Treatment with AA did not differ from control for color and general appearance, while treatment with 2% CaCl2 at 20 degrees C maintained the best quality, with less intensity of browning, best general appearance and purchase intent and least strange odor at the end of evaluation period.

Numerical simulation of anisotropic polymeric foams

This paper shows in detail the modelling of anisotropic polymeric foam under compression and tension loadings, including discussions on isotropic material models and the entire procedure to calibrate the parameters involved. First, specimens of poly(vinyl chloride) (PVC) foam were investigated through experimental analyses in order to understand the mechanical behavior of this anisotropic material. Then, isotropic material models available in the commercial software Abaqus (TM) were investigated in order to verify their ability to model anisotropic foams and how the parameters involved can influence the results. Due to anisotropy, it is possible to obtain different values for the same parameter in the calibration process. The obtained set of parameters are used to calibrate the model according to the application of the structure. The models investigated showed minor and major limitations to simulate the mechanical behavior of anisotropic PVC foams under compression, tension and multi-axial loadings. Results show that the calibration process and the choice of the material model applied to the polymeric foam can provide good quantitative results and save project time. Results also indicate what kind and order of error one will get if certain choices are made throughout the modelling process. Finally, even though the developed calibration procedure is applied to specific PVC foam, it still outlines a very broad drill to analyze other anisotropic cellular materials.

Study of an anisotropic polymeric cellular material under compression loading

This paper emphasizes the influence of micro mechanisms of failure of a cellular material on its phenomenological response. Most of the applications of cellular materials comprise a compression loading. Thus, the study focuses on the influence of the anisotropy in the mechanical behavior of cellular material under cyclic compression loadings. For this study, a Digital Image Correlation (DIC) technique (named Correli) was applied, as well as SEM (Scanning Electron Microscopy) images were analyzed. The experimental results are discussed in detail for a closed-cell rigid poly (vinyl chloride) (PVC) foam, showing stress-strain curves in different directions and why the material can be assumed as transversely isotropic. Besides, the present paper shows elastic and plastic Poisson's ratios measured in different planes, explaining why the plastic Poisson's ratios approach to zero. Yield fronts created by the compression loadings in different directions and the influence of spring-back phenomenon on hardening curves are commented, also.