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.

Tabu search to solve the Synchronized and Integrated Two-Level Lot Sizing and Scheduling Problem

This paper proposes a tabu search approach to solve the Synchronized and Integrated Two-Level Lot Sizing and Scheduling Problem (SITLSP). It is a real-world problem, often found in soft drink companies, where the production process has two integrated levels with decisions concerning raw material storage and soft drink bottling. Lot sizing and scheduling of raw materials in tanks and products in bottling lines must be simultaneously determined. Real data provided by a soft drink company is used to make comparisons with a previous genetic algorithm. Computational results have demonstrated that tabu search outperformed genetic algorithm in all instances. Copyright 2011 ACM.

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.

Strategies to model scheduling decisions to plan the soft drink production process

In this paper we present a mixed integer model that integrates lot sizing and lot scheduling decisions for the production planning of a soft drink company. The main contribution of the paper is to present a model that differ from others in the literature for the constraints related to the scheduling decisions. The proposed strategy is compared to other strategies presented in the literature.

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.

Analysis of ensemble models in the medium term hydropower scheduling

The medium term hydropower scheduling (MTHS) problem involves an attempt to determine, for each time stage of the planning period, the amount of generation at each hydro plant which will maximize the expected future benefits throughout the planning period, while respecting plant operational constraints. Besides, it is important to emphasize that this decision-making has been done based mainly on inflow earliness knowledge. To perform the forecast of a determinate basin, it is possible to use some intelligent computational approaches. In this paper one considers the Dynamic Programming (DP) with the inflows given by their average values, thus turning the problem into a deterministic one which the solution can be obtained by deterministic DP (DDP). The performance of the DDP technique in the MTHS problem was assessed by simulation using the ensemble prediction models. Features and sensitivities of these models are discussed. © 2012 IEEE.

Irrigation management in pruned coffee tree crop

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Transaction scheduling using dynamic conflict avoidance

Software transaction memory (STM) systems have been used as an approach to improve performance, by allowing the concurrent execution of atomic blocks. However, under high-contention workloads, STM-based systems can considerably degrade performance, as transaction conflict rate increases. Contention management policies have been used as a way to select which transaction to abort when a conflict occurs. In general, contention managers are not capable of avoiding conflicts, as they can only select which transaction to abort and the moment it should restart. Since contention managers act only after a conflict is detected, it becomes harder to effectively increase transaction throughput. More proactive approaches have emerged, aiming at predicting when a transaction is likely to abort, postponing its execution. Nevertheless, most of the proposed proactive techniques are limited, as they do not replace the doomed transaction by another or, when they do, they rely on the operating system for that, having little or no control on which transaction to run. This article proposes LUTS, a lightweight user-level transaction scheduler. Unlike other techniques, LUTS provides the means for selecting another transaction to run in parallel, thus improving system throughput. We discuss LUTS design and propose a dynamic conflict-avoidance heuristic built around its scheduling capabilities. Experimental results, conducted with the STAMP and STMBench7 benchmark suites, running on TinySTM and SwissTM, show how our conflict-avoidance heuristic can effectively improve STM performance on high contention applications. © 2012 Springer Science+Business Media, LLC.

A heuristic algorithm based on multi-assignment procedures for nurse scheduling

This paper tackles a Nurse Scheduling Problem which consists of generating work schedules for a set of nurses while considering their shift preferences and other requirements. The objective is to maximize the satisfaction of nurses' preferences and minimize the violation of soft constraints. This paper presents a new deterministic heuristic algorithm, called MAPA (multi-assignment problem-based algorithm), which is based on successive resolutions of the assignment problem. The algorithm has two phases: a constructive phase and an improvement phase. The constructive phase builds a full schedule by solving successive assignment problems, one for each day in the planning period. The improvement phase uses a couple of procedures that re-solve assignment problems to produce a better schedule. Given the deterministic nature of this algorithm, the same schedule is obtained each time that the algorithm is applied to the same problem instance. The performance of MAPA is benchmarked against published results for almost 250,000 instances from the NSPLib dataset. In most cases, particularly on large instances of the problem, the results produced by MAPA are better when compared to best-known solutions from the literature. The experiments reported here also show that the MAPA algorithm finds more feasible solutions compared with other algorithms in the literature, which suggest that this proposed approach is effective and robust. © 2013 Springer Science+Business Media New York.

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.

A priori reformulations for joint rolling-horizon scheduling of materials processing and lot-sizing problem

In many production processes, a key material is prepared and then transformed into different final products. The lot sizing decisions concern not only the production of final products, but also that of material preparation in order to take account of their sequence-dependent setup costs and times. The amount of research in recent years indicates the relevance of this problem in various industrial settings. In this paper, facility location reformulation and strengthening constraints are newly applied to a previous lot-sizing model in order to improve solution quality and computing time. Three alternative metaheuristics are used to fix the setup variables, resulting in much improved performance over previous research, especially regarding the use of the metaheuristics for larger instances. © 2013 Elsevier Ltd. All rights reserved.