Influence of the number of load cycles to obtain the stiffness properties of angico preto (Anadenanthera macrocarpa) wood specie

The tests used to obtain the stiffness properties of wood are made with two loading cycles, as defined by the Brazilian standard ABNT NBR 7190 (Design of Timber Structures). However, the possibility of reducing the number of cycles allows decrease the operating time of the machine, resulting in reduced spending on electricity used during the tests. This research aimed to investigate, with the aid of the analysis of variance (ANOVA), the influence of the use of three load cycles to obtain the modulus of elasticity in compression parallel to grain (Ec0), in tensile parallel to the grain (Et0), in bending (Em) and in compression perpendicular to the grain (Ec90) of Angico Preto (Anadenanthera macrocarpa) wood specie. For the number of cycles and stiffness were manufactured 12 samples, totaling 144 specimens. The results of the ANOVA revealed statistical equivalence between the stiffness properties for both load cycle numbers evaluated, indicating that it is possible to carry out the tests with a single charge cycle, allowing savings in time and energy in the operation of the equipment.

Evaluating distributed time-varying generation through a multiobjective index

In the last decade, distributed generation, with its various technologies, has increased its presence in the energy mix presenting distribution networks with challenges in terms of evaluating the technical impacts that require a wide range of network operational effects to be qualified and quantified. The inherent time-varying behavior of demand and distributed generation (particularly when renewable sources are used), need to be taken into account since considering critical scenarios of loading and generation may mask the impacts. One means of dealing with such complexity is through the use of indices that indicate the benefit or otherwise of connections at a given location and for a given horizon. This paper presents a multiobjective performance index for distribution networks with time-varying distributed generation which consider a number of technical issues. The approach has been applied to a medium voltage distribution network considering hourly demand and wind speeds. Results show that this proposal has a better response to the natural behavior of loads and generation than solely considering a single operation scenario.

Electrocoagulation/flotation followed by fluidized bed anaerobic reactor applied to tannery effluent treatment

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

Semeadura conjugada à aplicação de herbicidas em plantio direto e convencional, na cultura do milho (Zea mays L.)

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

Zirconia-Porcelain Bonding: Effect of Multiple Firings on Microtensile Bond Strength

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

Optimized dynamic response of parallel operation of two single phase inverters based on evolutionary theory

In this work it is proposed an optimized dynamic response of parallel operation of two single-phase inverters with no control communication. The optimization aims the tuning of the slopes of P-ω and Q-V curves so that the system is stable, damped and minimum settling time. The slopes are tuned using an algorithm based on evolutionary theory. Simulation and experimental results are presented to prove the feasibility of the proposed approach. © 2010 IEEE.

Parthenogenetic activation of bovine oocytes using single and combined strontium, ionomycin and 6-dimethylaminopurine treatments

In vitro-matured (IVM) bovine oocytes were activated with single and combined treatments of strontium (S), ionomycin (1) and 6-DMAP (D). Using oocytes IVM for 26 h, we observed that activation altered cell cycle kinetics (faster progression, MIII arrest, or direct transition from MII to pronuclear stage) when compared to in vitro fertilization. The effect of oocyte age on early parthenogenesis was assessed in oocytes IVM for 22, 26 and 30 h. Better results in pronuclear development were obtained in treatments ISD (81.7%) at 22 h; D (66.7%), IS (63.3%), ID (73.3%) and ISD (76.7%) at 26 h; and D (86.7%), IS (85.0%) and ID (78.3%) at 30 h. Higher cleavage occurred on ISD (80.0%) at 22 h; ID (83.3%) and ISD (91.7%) at 26 h; and 1 (86.7%), IS (90.0%), ID (85.0%) and ISD (95.0%) at 30 h. More blastocysts were achieved in ID (25.0%) and ISD (18.3%) at 22h; and in ID at 26h (45.0%) and 30h (50.0%). We also observed that IS allowed higher haploid (77.4%) embryonic development, whilst ID was better for diploid (89.1%) development. It was concluded that association of S and D without I was not effective for blastocyst development; treatments using S were less influenced by oocyte age, but when S was associated with D there was a detrimental effect on aged oocytes; treatment ISD promoted higher activation and cleavage rates in young oocytes and ID protocol was the best for producing blastocysts.

Optimisation of environmental gas cleaning routes for solid wastes cogeneration systems. Part II - Analysis of waste incineration combined gas/steam cycle

In the first paper of this paper (Part I), conditions were presented for the gas cleaning technological route for environomic optimisation of a cogeneration system based in a thermal cycle with municipal solid waste incineration. In this second part, an environomic analysis is presented of a cogeneration system comprising a combined cycle composed of a gas cycle burning natural gas with a heat recovery steam generator with no supplementary burning and a steam cycle burning municipal solid wastes (MSW) to which will be added a pure back pressure steam turbine (another one) of pure condensation. This analysis aims to select, concerning some scenarios, the best atmospheric pollutant emission control routes (rc) according to the investment cost minimisation, operation and social damage criteria. In this study, a comparison is also performed with the results obtained in the Case Study presented in Part I. (c) 2007 Elsevier Ltd. All rights reserved.

Single-phase high power-factor boost ZCS pre-regulator operating in critical conduction mode

This paper presents a new single-phase interleaved high power factor boost pre-regulator operating in critical conduction mode, where the switches and boost diode performing zero-current commutations during its turn-off, eliminating the disadvantages related to the reverse recovery losses and electromagnetic interference problems of the boost diode, when operating in the continuous conduction mode. The interleaving technique is applied in the power cell, providing a significant input current ripple reduction in comparison to discontinuous mode of operation, due to its input current continuous conduction operation. This paper presents a complete modeling for the converter operating in critical conduction mode, resulting in an improved design procedure for interleaved techniques with high input power factor, a complete design procedure, and main simulation results from a design example with two interleaved cells rated at 1kW, 400V output voltage and 220V rms input voltage.

A novel single-phase ZCS-PWM high-power-factor boost rectifier

This paper presents a novel single-phase high-power-factor (HPF) pulsewidth-modulated (PWM) boost rectifier featuring soft commutation of the active switches at zero current (ZC), It incorporates the most desirable properties of conventional PWM and soft-switching resonant techniques.The input current shaping is achieved with average current mode control and continuous inductor current mode.This new PWM converter provides ZC turn on and turn off of the active switches, and it is suitable for high-power applications employing insulated gate bipolar transistors (IGBT's),The principle of operation, the theoretical analysis, a design example, and experimental results from a laboratory prototype rated at 1600 W with 400-Vdc output voltage are presented. The measured efficiency and the power factor were 96.2% and 0.99%, respectively, with an input current total harmonic distortion (THD) equal to 3.94%, for an input voltage with THD equal to 3.8%, at rated load.

DCM Boost interleaved converter for operation in AC and DC to trolleybus application

This paper is based on the development and experimental analysis of a DCM Boost interleaved converter suitable for application in traction systems of electrical vehicles pulled by electrical motors (Trolleybus), which are powered by urban DC or AC distribution networks. This front-end structure is capable of providing significant improvements in trolleybuses systems and in the urban distribution network costs, and efficiency. The architecture of proposed converter is composed by five boost power cells in interleaving connection, operating in discontinuous conduction mode. Furthermore, the converter can operate as AC-DC converter, or as DC-DC converter providing the proper DC output voltage range required by DC or AC adjustable speed drivers. Therefore, when supplied by single-phase AC distribution networks, and operating as AC-DC converter, it is capable to provide high power factor, reduced harmonic distortion in the input current, complying with the restrictions imposed by the IEC 61000-3-4 standards. The digital controller has been implemented using a low cost FPGA and developed totally using a hardware description language VHDL and fixed point arithmetic. Thus, two control strategies are evaluated considering the compliance with input current restrictions imposed by IEC 61000-3-4 standards, the regular PWM modulation and a current correction PWM modulation. In order to verify the feasibility and performance of the proposed system, experimental results from a 15 kW low power scale prototype are presented, operating in DC and AC conditions.

Design of a Takagi-Sugeno Fuzzy Regulator for a Set of Operation Points

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Single nucleotide polymorphisms in the bovine genome are associated with the number of oocytes collected during ovum pick up

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

The reproductive cycle of Callinectes danae Smith, 1869 (Decapoda, Portunidae) in the Ubatuba Region, Brazil

Callinectes danae Smith, 1869, known as siri-azul, is an important fishery resource along the Brazilian coast. The reproductive cycle of this species was studied based on their moult cycle and the development of their gonads. The animals were collected with an otter-trawl in the Ubatuba region (23 degrees 26'S 45 degrees 02'W) every other month from July 1991 to May 1993. A total of 1826 specimens were captured: 788 males and 1038 females. Ovigerous females and specimens with developed gonads in both sexes were found in all months sampled. In females, moult activity was recorded in all size classes while in males, it was verified from 20-27 mm to 90-97 mm size classes. The females produced more than one clutch during a single reproductive season, a fact evidenced by the presence of ovigerous females with ovaries in all the development phases. The species C. danae reproduces continuously, like most brachyurans from tropical waters.

Variations in dynamic knee valgus and gluteus medius onset timing in non-athletic females related to hormonal changes during the menstrual cycle

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