Scanning electron microscopy analysis of RinsEndo system and conventional irrigation for debris removal

A new device for irrigation, which presents hydrodynamic activation based on the pressure-suction technology, has recently been introduced to the market: the Rinsendo system. This study compared the efficacy of the Rinsendo system and conventional (manualdynamic) irrigation in the removal of debris from the root canal walls, using scanning electron microscopy (SEM). Twenty mandibular premolars with completely formed roots were selected and randomly divided into group 1 (irrigation with the Rinsendo system) and group 2 (conventional irrigation). The canals were irrigated with 1 ml of saline at each change of instrument. instrumentation started with a #15 K file and continued up to a #40 K file, which was standardized as the working length instrument. Then, the teeth were sectioned in buccolingual direction and the halves were sputter-coated with gold and examined by SEM. The apical, middle and cervical root canal thirds were evaluated, and the results were analyzed statistically by the Mann-Whitney test for comparison between methods, Kruskal-Wallis test for comparison among thirds, and Miller test for individual comparisons. A significance level of 5% was set for all analyses. The results did not show significant differences (p>0.05) between methods at each third and among thirds for each technique analyzed individually. in conclusion, there was no difference in the cleaning ability of the Rinsendo system and conventional irrigation.

Dry matter yield and nutritional value of Marandu grass under nitrogen fertilization and irrigation in cerrado in São Paulo

The aim of this study was to evaluate dry matter yield and nutritional value of palisade grass (Brachiaria brizantha cv. Marandu) using nitrogen doses and sprinkler irrigation in two periods of the year, aiming at reducing seasonality of forage production. It was used a randomized block design in a split-plot scheme, with five doses of nitrogen (0, 50, 100, 150, and 200 kg/ha/cut), and the sub-plots were defined by the seasons of the year (wet and dry season), with and without irrigation. During the wet season, in the plots with and without irrigation, doses of 175 and 161 kg/ha/cut promoted the highest dry matter yields. During the dry season, 171 kg ha -1N with irrigation resulted in the highest dry matter yield. During the same season, there was no response to N fertilization in the lack of irrigation. Average contents of CP were 10% with and without irrigation. Contents of neutral detergent fiber decreased with nitrogen doses, while acid detergent fiber was not affected by fertilization. Plots under irrigation reached the maximal acid detergent fiber content at N dose of 60 kg ha -1. Irrigation promotes increase of 15% increase in dry matter yield and it increases contents of neutral detergent fiber. © 2010 Sociedade Brasileira de Zootecnia.

Seedling growth of Schizolobium parahyba on different substrates and irrigation levels

The present study aimed to assess the behavior of seedlings of Schizolobium parahyba (Vell.) Blake growing on different substrates and irrigation levels, and to study the use of urban waste compost in substrates. The experiment was carried out in the College of Agricultural Sciences, Universidade Estadual Paulista (UNESP), Department of Agricultural Engineering, Jaboticabal Campus, state of São Paulo, Brazil. The experimental design used was completely randomized, consisting of 30 treatments in a factorial design with 15 substrates and two irrigation levels in four replicates. The substrates were composed of different materials: urban waste, Plantmax®, dry cattle manure, vermiculite and soil. For the study of seedling growth, the following characteristics were evaluated: height (H), root-collar diameter (D), number of leaves, shoot dry weight, root dry weight, total dry weight, H/D ratio, Dickson's quality index, and the ratio between height and shoot dry weight (H/SDW). Assessments of the first three characteristics were carried out 20, 35, 50 and 65 days after sowing. Results showed that urban waste compost increased the growth of Schizolobium parahyba. There were significant differences for the irrigation levels tested; with better results for 150% ET compared to 100% ET irrigation level.

Optimal moment to change pressure regulator and sprayer kit on center pivot irrigation machines: a theoretical proposal

A theoretical model was developed in order to determine the optimal moment for substituting the sprayer and pressure regulator kit on a center pivot irrigation machine. The model is based on the hypothesis that pressure regulator and sprayer deterioration decrease irrigation uniformity. To compensate the deficit that happens at under irrigated areas, an increase on irrigation depth is required. The model considers: additional water consumption and energy costs, maintenance and labor costs, as well as yield losses associated with under or over irrigated areas. The sum of all these components is compared to buying and installing a new spray kit cost, allowing the farmer to decide the best moment to renovate the sprayer and pressure regulator kits on a center pivot irrigation machine based on economic criteria.

Optimal moment to change pressure regulator and sprayer kit on center pivot irrigation machines: application to a study case

A theoretical model developed by the authors for determining the optimal moment to substitute sprayer and pressure regulator kit on a center pivot irrigating potatoes and beans has been applied. The methodology compares the sum of the costs due to additional consumption of water and energy, maintenance and labor, as well as yield losses associated to areas with deficit or over irrigation to the costs due to buy and install a new sprinkling set on the pivot. The results showed that for a reduction of 3.07% of the Hermann and Hein’s Uniformity Coefficient (UCh), the substitution of the sprinkling module on the pivot is justified when potatoes and beans are cultivated.

Anaerobic effluent disinfected with ozone/hydrogen peroxide efluente anaeróbio desinfetado com ozônio/peróxido de hidrogênio

This research aimed at studying the oxidation process, to verify the effectiveness of coliform inactivation and to evaluate the formation of ozonation disinfection byproducts (DBP) in anoxic sanitary wastewater treated with ozone/hydrogen peroxide applied at doses of 2.6 mg O3 L-1 and 2.0 mg H2O2 L-1 with contact time of 10 min and 8.1 mg O3 L-1 and 8.0 mg H2O2 L-1 with contact time of 20 min. The mean chemical oxygen demand (COD) reductions were 7.50 and 9.40% for applied dosages of 2.5-2.8 and 6.4-9.4 mg O3 L-1 + 2.0 and 8.0 mg H2O2.L-1, respectively. The Escherichia coli (E. coli) inactivation range was 2.98-4.04 log10 and the total coliform inactivation range was 2.77-4.01 log10. The aldehydes investigated were formaldehyde, acetaldehyde, glyoxal and methylglyoxal. It was observed only the formation of acetaldehyde that ranged 5.53 to 29.68 μg L-1.

Relationship between citrus productivity and indicators of uniformity in trickle irrigation system

In trickle irrigation systems, the design is based on the pre-established emission uniformity (EU) which is the combined result of the equipment characteristics and its hydraulic configuration. However, this desired value of the EU may not be confirmed by the final project (in field conditions) and neither by the yield uniformity. The hypotheses of this research were: a) the EU of a trickle irrigation system at field conditions is equal to the emission uniformity pre-established in the its design; b) EU has always the lowest value when compared with other indicators of uniformity; c) the discharge variation coefficient (VC) is not equal to production variation coefficient in the operational unit; d) the difference between the discharge variation coefficient and the productivity variation coefficient depends on the water depth applied. This study aimed to evaluate the relationship between EU used in the irrigation system design and the final yield uniformity. The uniformity indicators evaluated were: EU, distribution uniformity (UD) and the index proposed by Barragan & Wu (2005). They were compared estimating the performance of a trickle irrigation system applied in a citrus orchard with dimensions of 400m x 600m. The design of the irrigation system was optimized by a Linear Programming model. The tree rows were leveled in the larger direction and the spacing adopted in the orchard was 7m x 4m. The manifold line was always operating on a slope condition. The sensitivity analysis involved different slopes, 0, 3, 6, 9 and 12%, and different values of emission uniformity, 60, 70, 75, 80, 85, 90 and 94%. The citrus yield uniformity was evaluated by the variation coefficient. The emission uniformity (EU) after design differed from the EU pre-established, more sharply in the initial values lower than 90%. Comparing the uniformity indexes, the EU always generated lower values when compared with the UD and with the index proposed by Barragan. The emitter variation coefficient was always lower than the productivity variation coefficient. To obtain uniformity of production, it is necessary to consider the irrigation system uniformity and mainly the water depth to be applied.

Model to increase the lateral line length of drip irrigation systems

Non-pressure compensating drip hose is widely used for irrigation of vegetables and orchards. One limitation is that the lateral line length must be short to maintain uniformity due to head loss and slope. Any procedure to increase the length is appropriate because it represents low initial cost of the irrigation system. The hypothesis of this research is that it is possible to increase the lateral line length combining two points: using a larger spacing between emitters at the beginning of the lateral line and a smaller one after a certain distance; and allowing a higher pressure variation along the lateral line under an acceptable value of distribution uniformity. To evaluate this hypothesis, a nonlinear programming model (NLP) was developed. The input data are: diameter, roughness coefficient, pressure variation, emitter operational pressure, relationship between emitter discharge and pressure. The output data are: line length, discharge and length of the each section with different spacing between drippers, total discharge in the lateral line, multiple outlet adjustment coefficient, head losses, localized head loss, pressure variation, number of emitters, spacing between emitters, discharge in each emitter, and discharge per linear meter. The mathematical model developed was compared with the lateral line length obtained with the algebraic solution generated by the Darcy-Weisbach equation. The NLP model showed the best results since it generated the greater gain in the lateral line length, maintaining the uniformity and the flow variation under acceptable standards. It had also the lower flow variation, so its adoption is feasible and recommended.

Irrigation management in pruned coffee tree crop

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of intensification of the amazon river prawn, macrobrachium amazonicum, grow-out on effluent quality

Studies to determine suitable levels of intensification are essential for developing sustainable aquaculture. The objective of this study was to evaluate the quality of effluents discharged from ponds stocked with 10 (D10), 20 (D20), 40 (D40), and 80 (D80) postlarvae of Macrobrachium amazonicum/m2. Intake and effluent water samples were taken throughout a 5.5-mo grow-out cycle. In that study, twelve 0.01-ha earthen ponds were stocked postlarvae with 0.01g. Average water exchange rate was 15%/d; water was discharged from the bottom of the ponds. Prawns were fed a commercial feed with 38% crude protein according to their biomass (3-10%) and the concentration of dissolved oxygen (DO). In our research, temperature, turbidity, total suspended solids, conductivity, DO, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), N-ammonia, N-nitrite, N-nitrate, N-Kjeldahl nitrogen, total phosphorus, and soluble orthophosphate were measured every 15d throughout the experiment in the early morning (0630 to 0730h). Turbidity was lower in D10 than in D20 and D40 and total phosphorus was higher in D80 than in D10 and D20. An analysis of principal components comparing treatments and intake water showed three groups: intake, D10 and a cluster of D20, D40, and D80. On the basis of the water characteristics found in our study it appears that the farming of M. amazonicum is likely to have a low environmental impact, at least up to a stocking density of 80prawns/m2. © by the World Aquaculture Society 2013.

Resposta da alface à aplicação de biofertilizante sob dois níveis de irrigação

The use of biofertilizers is interesting for agriculture as being an economical alternative as well as it is environmentally friendly by using organic waste and reducing the application of mineral fertilizers. The aim of this study was to evaluate the effect of biofertilizer doses of bovine origin (biodigester effluent) applied on the ground and two levels of irrigation on lettuce. The experiment was conducted under protection of a greenhouse in pots, applying to the soil different doses of biofertilizer of bovine origin obtained from anaerobic reactor (10, 20, 40 and 60 m3 ha-1) and mineral fertilizer as a witness in two irrigation levels calculated at 50 and 100% of reference evapotranspiration. The lettuce plants were analyzed in their: Height, leaves number, crown diameter, fresh weight and dry weight of shoots. The biofertilizer treatments showed better results than the mineral fertilizer and has increased with increasing doses of biofertilizer, the highest dose (60 m3 ha-1) showed the best results in all variables. For dry, mineral fertilization showed higher values. The irrigation levels had no effect on plant growth.

Efficacy of four irrigation needles in cleaning the apical third of root canals

This study aimed to evaluate the influence of irrigation needle gauge and design, and the final root canal diameter on the apical cleaning efficacy. Twelve human mandibular incisors were used. At different stages of root canal widening (sizes 20, 30 and 40 K-files), root canals were filled with radiopaque contrast medium. Four different needles were evaluated: 23G with side opening, 22G with apical opening, 30G with side opening and 30G with apical opening. Irrigation was carried out with 2 mL distilled water. The same tooth was radiographed with a digital system several times to assess the four types of needle in those three stages of canal widening. Pre-irrigation (canals filled with contrast) and post-irrigation (canals with remaining contrast) images were submitted to digital subtraction using the Adobe Photoshop CS4 program. Pre-irrigation (filled with contrast) and subtracted (cleaned by irrigation) areas were outlined by a trained and blinded operator using the Image Tool 3.0 software. Their ratio was calculated to express the percentage of apical cleaning in each stage of canal widening (sizes 20, 30 and 40 K-files) with each of the four needles. Data obtained were subjected to one-way ANOVA and Tukey's tests. The 30G needles with side and apical opening promoted better apical cleaning at all stages of root canal widening (p<0.05). In conclusion, smaller diameter needles were more efficacious in cleaning the apical third of the root canals, regardless of their design.

Contaminação das águas subterrâneas por nitrogênio devido à irrigação com efluente do tratamento de esgoto

Agriculture is an activity in which there is the possibility of using lower quality water and reuse appears as an alternative for irrigation. However, the negative environmental effects of reuse must be understood. The objective of the present work was to verify the potential of groundwater contamination by nitrogen duo to drip irrigation with effluent from domestic wastewater treatment. Three crop cycles of lettuce cv. Raider were conducted, the first between October and November 2009, the second in April and May 2010 and the third one in June and July 2010. The use of effluents was compared with potable water at accumulated water depths of 98.8 mm for the first, 98.4 mm for the second and 119 mm for the third cycle. Soil percolate concentrations of nitrate, nitrite and ammonia were studied at 0.25 m and 0.50 m depths in a completely randomized design. Percolate concentrations of nitrite and ammonia in soil irrigated with effluents showed no groundwater contamination risk. Nitrate however, caused concern, albeit with similar concentrations for both effluent and potable water.

Effect of final irrigation protocols on microhardness and erosion of root canal dentin

The aim of this study was to evaluate the effect of final irrigation protocols (17% EDTA, BioPure MTAD, SmearClear, and QMiX) on microhardness and erosion of root canal dentin. Fifty roots were sectioned transversely at the cement-enamel junction and each root was sectioned horizontally into 4-mm-thick slices. The samples were divided into five groups (n=10) according to the final irrigation protocol: G1: distilled water (control group); G2: 17% EDTA; G3: BioPure MTAD; G4: SmearClear; and G5: QMiX. The dentin microhardness was then measured with a load of 25 g for 10 s. Initially, the reference microhardness values were obtained for the samples without any etching. The same samples were then submitted to the final irrigation protocols. A new measure was realized and the difference between before and after the procedures was the dentin microhardness reduction. In sequence, the specimens were submitted to SEM analysis to verify the dentinal erosion. The Kruskal Wallis and Dunn tests (α=5%) were used to compare the results. The dentin microhardness decreased for all final irrigation protocols. There was no significant difference between groups 2, 3, 4, and 5 (P>0.05), but this groups presented significant dentin microhardness reduction than G1 (P<0.05). In G2, occurred the highest incidence of dentinal erosion (P<0.05). 17% EDTA, BioPure MTAD, SmearClear, and QMiX promoted significant dentin microhardness reduction. © 2013 Wiley Periodicals, Inc.

Tratamento de manipueira de fecularia em biodigestor anaeróbio para disposição em corpo receptor, rede pública ou uso em fertirrigação

Pós-graduação em Agronomia (Energia na Agricultura) - FCA