Sistema de produção misto de caprino na região central do estado do Rio Grande do Norte

This study aimed to evaluate the performance and profitability of Canindé goats kept under semi-intensive management in mix farming system. 84 animals were used, being 81 does e three bucks.. The means of fertility rate at parturition, prolificacy and percentages of pregnant, kid survival and reproductive rate were compared by Tukey test at significance level of 5.0%. The kid weights from birth to weaning were submitted to variance analysis considering sex and birth type and the means were compared by Tukey test at 5.0% of significance. The percentages of fertility rate by ultrassographic were 91.36 and parturition 74.84. The prolificacy was 1.53. Independently of sex the mortality rate of kids from birth to weaning was 12.3. The average weights of offspring were 2.11 and 1.92 kg and 6.74 and 6.84 kg for male and female offspring at birth and weaning, in this order. The average weights of kids, meaning PN, P28, P56, P63, in the first season of kidding were 2.11 ± 0.46 kg, 3.63 ± 1.04 kg, 5.96 ± 158 kg and 6.74 ± 1.79 kg. There was significant differences (P<0,05) only to birth weight of kids sons of buck 135. However, the fertility at parturition for first and second breeding seasons (BS) were 87.65 and 62.96, respectively (P<0.05). The prolificacy was 1.58 and 1.47 to first and second BS in this order. The percentages of offspring survival from birth to weaning, to first and second BS were 92.86 and 80.00, respectively. From the first BS the reproduction rate was 1.28 while in the second was 0.74. After weaning the duration of lactation was 104 days to first breeding parturition and 38 days in the second one. The total milk production was 853.50 kg. The kids weight gain was influenced by season of year, wet and dry and buck (P<0.05). Were concluded that the seasons of year when breeding season and parturition occur strongly affected the productive performance and profitability of production system

Surface characteristics analysis of polypropylene treated by dielectric barrier discharge at atmospheric pressure

Polypropylene (PP) samples were treated by Dielectric Barrier Discharge (DBD) in order to modify their surface characteristics. The XPS analysis reveals that the DBD treatment added oxygen atoms to the PP surface. These polar groups cause increase in the wettability as shown by water contact angle measurements. The formation of low-molecular-weight oxidized materials (LMWOMs) in the form of small nodules on the PP surface was observed by atomic force microscopy (AFM). The presence of oxygen polar groups on the PP surface was also confirmed by infrared spectroscopy (FTIR). All analysis were performed before and after rinsing the treated samples in water and showed that the LMWOM can be removed from the surface by polar solvents.

Alquilação redutiva da quitosana a partir do glutaraldeído e 3-amino-1-pr

Chitosan derivatives were prepared by reductive alkylation using glutaraldehyde and 3-amino-1-propanol. The reducing agent used was the sodium borohydride. Tests of solubility, stability and viscosity were performed in order to evaluate these parameters effects in the reaction conditions (molar ratio of the reactants and presence of nitrogen in the reaction system). The molecular structure of commercial chitosan was determined by infrared (IR) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR). The intrinsic viscosity and average molecular weight of the chitosan were determined by viscosimetry in 0.3 M acetic acid aqueous solution 0.2 M sodium acetate at 25 ºC. The derivatives of chitosan soluble in aqueous acidic medium were characterized by 1H NMR. The rheological behavior of the chitosan and of the derivative of chitosan (sample QV), which presented the largest viscosity, were studied as a function of polymer concentration, temperature and ionic strength of the medium. The results of characterization of the commercial chitosan (the degree of deacetylation obtained equal 78.45 %) used in this work confirmed a sample of low molar weight (Mv = 3.57 x 104 g/mol) and low viscosity (intrinsic viscosity = 213.56 mL/g). The chemical modification of the chitosan resulted in derivatives with thickening action. The spectra of 1H NMR of the soluble derivatives in acid aqueous medium suggested the presence of hydrophobic groups grafted into chitosan in function of the chemical modification. The solubility of the derivatives of chitosan in 0.25 M acetic acid aqueous solution decreased with increase of the molar ratio of the glutaraldehyde and 3-amino-1-propanol in relation to the chitosan. The presence of nitrogen and larger amount of reducing agent in reaction system contributed to the increase of the solubility, the stability and the viscosity of the systems. The viscosity of the polymeric suspensions in function of the shear rate increased significantly with polymer concentration, suggesting the formation of strong intermolecular associations. The chitosan presented pseudoplastic behavior with the increase in polymer concentration at a low shear rate. The derivative QV presented pseudoplastic behavior at all concentrations used and in a large range of shear rate. The viscosity of chitosan in solution decreased with an increase of the temperature and with the presence of salt. However, there was an increase of the viscosity of the chitosan solution at higher temperature (65 ºC) and ionic strength of the medium which were promoted by hydrophobic associating of the acetamide groups. The solutions of the chitosan derivatives (sample QV) were significantly more viscous than chitosan solution and showed higher thermal stability in the presence of salt as a function of the hydrophobic groups grafted into chitosan backbone

Structural characterization of wild rubbers, microstructure of the rubber extracted from ficus elastica by C-13-NMR

Low molecular weight fractions of polyisoprene extracted from Ficus elastica Herb. ex Hornem. were studied by C-13-NMR. The identification of 2-3 trans terminal units at the end of the polymer chain needed the acquisition of more than 17 000 transients. (C) 2000 Elsevier B.V. Ltd. All rights reserved.