A Time-domain Harmonic Power-Flow Analysis in Electrical Energy Distribution Networks, Using Norton Models for Non-linear Loading

The purpose of this paper is to present the application of a three-phase harmonic propagation analysis time-domain tool, using the Norton model to approach the modeling of non-linear loads, making the harmonics currents flow more appropriate to the operation analysis and to the influence of mitigation elements analysis. This software makes it possible to obtain results closer to the real distribution network, considering voltages unbalances, currents imbalances and the application of mitigation elements for harmonic distortions. In this scenario, a real case study with network data and equipments connected to the network will be presented, as well as the modeling of non-linear loads based on real data obtained from some PCCs (Points of Common Coupling) of interests for a distribution company.

BIOMOLECULES EXTRACTED BY ATPS: PRACTICAL EXAMPLES

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

Controle de velocidade de um motor de indução trifásico usando técnicas de ajuste empírico para bancada de teste no laboratório de automação

This work aims to make the closed loop control of a three phase induction motor, through the integration of the following equipment: a frequency inverter, the actuator system; a programmable logic controller (PLC), the controller; an encoder, the velocity sensor, used as a feedback monitoring the control variable and the three-phase induction motor, the plant to be controlled. The control is performed using a Proportional - Integrative - Derivative (PID) approach. The PLC has a help instruction, which performs the auto adjustment of the controller, that instruction is used and confronted with other adjustment methods. There are several types of methods adjustments to the PID controllers, where the empirical methods are addressed in this work. The system is deployed at the Interface and Electro Electronic Control laboratory in the Universidade Estadual Paulista Júlio Mesquita Filho, Guaratinguetá, São Paulo, then, in the future, this work becomes an experiment to be conducted in the classroom, allowing undergraduate students to develop a greater affinity to the programs used by the PLC as well as studies of undergraduate and graduate works with the help of assembly made

Proteção de motores elétricos de grande porte

Large electric motors require greater care when driving, especially during continuous operation since they are part of day-to-day manufacturing sector, acting essentially to ensure that no damage occurs to the production process and equipment that are part of the same system. This work includes the analysis of electrical protection in a system comprised of a three phase induction motor driven by a frequency converter as well as an analysis of the functions of a multifunction electronic relay. It is presented a comparison between the existing functions in a converter and a relay and a real case is described in order to exemplify the use of an electric motor and features that are aimed at their protection, and the system in which it is inserted. Based on the results, it is of great importance in this field of performance studies, generating relevant results, which may be exposed in order to unify into a single document, different sources of information that are arranged randomly, improve utilization motor and extend the life of equipment forming part of the electrical installation

Avaliação da auto-suficiência energética de reatores anaeróbios no tratamento de esgoto sanitário e água cinza

The anaerobic treatment of sewage is widely employed in Brazil and it is an appreciated way for the treatment of effluents, helping to reduce the environmental impact in rivers. The methane gas obtained from the process can be applied to improve the energetic efficiency of the system, reducing the amount of waste and the cost of the treatment process. This work presents the net energy balance of anaerobic reactors applied to the treatment of sewage. The analysis was performed considering full-scale and laboratory-scale treatment systems. In laboratory scale, the results from three kinds of systems were compared regarding the biological treatment of greywater. Two of them (UASB7 and UASB12) were anaerobic and the other one was a combined anaerobic-aerobic system (UASB7/SBR6). Greywater methanization (compared to theoretical maximum) was calculated considering 100% removal (g BOD/day), the literature percentage removal and the anionic surfactant presence in the effluentt. For each of these three cases, the efficiencies were, respectively, 16.9%, 43.6% and 51.3% in UASB7 reactor, 25.6%, 50.3% and 59.2% in UASB12 reactor and 30.6%, 61.2% and 71.9% in UASB7/SBR6 reactor. The energetic potential was found to be 4.66x10-4, 7.77x10-4 and 5.12x10-4 kWh/L for the UASB7, UASB12 and UASB7/SBR6 reactors, respectively. The pumping system, the aeration (in the anaerobic-aerobic system) and the temperature controlled heating system were considered to calculate the energetic consumption. However, the third one was not employed since tropical regions like Brazil do not need heating systems and also because of its high energetic consumption. The calculated net energy balance in the reactors was negative in the case of greywater, respectively -0.16, -0.28 and -0.18 kWh/L for the reactors UASB7, UASB12 and UASB7/SRB6. In full scale (ETE Jardim das Flores - Rio Claro, SP), the average energy... (Complete abstract click electronic access below)

Avaliação do efeito da paralisação da aeração no tratamento biológico aeróbio da água residuária da indústria de farinha de mandioca

The cassava wastewater, generated during the cassava processing, is a pollutant and toxic waste. This study compared the efficiency of the cassava wastewater treatment in three batch aerobic systems with a ru1nning time of 24 hours, and aeration stoppage of 12h with 2,500, 6,000 and 10,000 mg COD L-1 . The systems were evaluated for COD, pH, SVI and F/M. The results showed that the reactor with aeration stoppage for 12 hours, with 2,500 mg COD L-1 , presented the best reduction in a process with considerable energy consumption saving compared to traditional continuous systems.

Proposta de uma metodologia de rebobinamento para converter motor de indução trifásico em monofásico

This paper proposes the conversion of a three-phase induction motor into single phase through rewinding its stator. It presents a methodology to calculate this rewinding process considering the constructive parameters of the, such as number of slots and number of poles, for instance. The operating principles of DC motors are highlighted to introduce the logic involved in the calculation of lap and wave windings. The construction of the stator three-phase induction motor generally uses the lap winding, which is also used in single phase to perform the conversion. The rewinding process is widely used for reconstruction of industrial and residential electric motors that have suffered damage or present flaws with use. Therefore, many three-phase electric motors that are discarded or disposed of could be recovered by the method described in this work for a purpose that contributes to energy efficiency or simply saving resources in single-phase uses

Correlación entre diferentes métodos de evaluación de color en el clareamiento dental. Correlation between different methods for co

The aim of this study was to evaluate the correlation of color change on bleaching tooth through delta E (ΔE) by the spectrophotometer Spectroshade (SS) and digital program Scanwhite (SW). Methods: 25 patient volunteers were recruited from Operative Dentistry at Universidad de Chile Dental School, between 18 to 30 years, with good oral hygiene. Exclusion criteria: Previous experienced tooth bleaching, anterior restorations, cervical lesions, pain dental, pregnant patient, stained teeth, malposition of the teeth and periodontal pathology. The bleaching was made in two sessions with three different bleaching systems which were randomly. The assessment of color change through ΔE was made on the two upper central incisors (N=50) by the SS and SW. The color in the same teeth were measured before (T0) and after (T1) of the bleaching treatment. Data were analyzed using test Spearman correlation coefficient (Rho) with a significant level of 95%. Results: The results showed a positive and significant correlation (0.676), with a statistically significant difference (p<0.05). Conclusion: There is correlation in the measurement of color change on bleaching tooth by SS and SW.

Short-term CO2-C emissions from soil prior to sugarcane (Saccharum spp.) replanting in southern Brazil

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

Preparo do solo e emissão de CO2, temperatura e umidade do solo em área canavieira

Soil tillage is one of the agricultural practices that may contribute to increase the loss of carbon through emission of CO2 (FCO2). The aim of this study was to investigate the effect of three soil tillage systems on FCO2, soil temperature and soil moisture in a sugarcane area under reform. The experimental area consisted of three tillage plots: conventional tillage (CT), conventional subsoiling (CS), and localized subsoiling (LS). FCO2, soil temperature and soil moisture were measured over a period of 17 days. FCO2 showed the highest value in CT (0.75 g CO2 m(-2) h(-1)). Soil temperature presented no significant difference (p > 0.05) between LS (26.2 degrees C) and CS (25.9 degrees C). Soil moisture was higher in LS (24%), followed by CS (21.8%) and CT (18.3%). A significant correlation (r = -0.71; p < 0.05) between FCO2 and soil temperature was observed only in CT. The conventional tillage presented a total emission (2,864.3 kg CO2 ha(-1)) higher than the emissions observed in CS (1,970.9 kg CO2 ha(-1)) and LS (1,707.7 kg CO2 ha(-1)). The conversion from CT to LS decreased soil CO2 emissions, reducing the contribution of agriculture in increasing the concentration of greenhouse gases in the atmosphere.

Prediction of soil shear strength in agricultural and natural environments of the Brazilian Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aplicação da teoria de potência conservativa para monitoramento do comportamento do motor de indução trifásico sob distúrbios de qualidade de energia

Pós-graduação em Engenharia Elétrica - FEB

Avaliação da resistência adesiva de diferentes sistemas resinosos de colagem ortodôntica

Recent orthodontic bonding materials have aimed to reduce the working time of the clinician, by simplifying the acid etching procedure by applying self-etching primer adhesive systems. However, the adhesion quality of these materials still demands investigation. Thus, the present study aimed to evaluate the bond strengths of three different adhesive systems. A hundred and eighty bovine lower incisors were cut and embebbed in acrylic resin matrices, in which orthodontic brackets were bonded with Transbond XT (2n = 60), Transbond XT Self Etching Primer (2n = 60) e Tyrian (2n = 60). For each composite, bond strength tests were executed immediately (n = 30) and 24 hours (n = 30) after the bonding, in the assay machine Versat 2000 (Pantec), by applying 500 Kgf of load at 1mm/min of velocity. Transbond XT, Transbond XT Self Etching Primer and Tyrian presented, respectively, average values of bond strength of 7.43, 7.09 and 3.41 MPa at the time immediately, and 7.42, 8.81 and 5.35 MPa at 24 hours after the bonding, where differences were statistically significant at 5% between Tyrian and Transbond groups at both observation times. It was concluded that Tyrian was the material that presented significant lower bond strength with regard to Transbond groups that were similar.

Biomolecules extracted by ATPs: practical examples

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

Avaliação de métodos de proteção para taludes em estrada não-pavimentada

This work presents the results of the efficiency of three protection methods of roads slopes, against the development of erosion processes.The methods anlyzed were: (1) grass planting "San Carlos" (Axonopus compressus), (2) litter, composed of remains of branches and leaves of eucalyptus E. Grandis, and (3) Compacted soil cover with a local soil with properties more resistant to erosion processes.The experiment consisted of assembly of four rectangular cells with 6 meters, three for protection systems in study and one was kept unprotected to evaluate the efficiency of the methods in study.The determination of the amount of eroded sediment was based on the sum of the solids in suspension and stored sediments in the geotextile bags.The results showed that, compared to the unprotected cell, the litter obtained a reduction of soil loss of 90%, while the grass enveloped and reduced 80% and 65% respectively.