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São João Evangelista, Brazil

Pereira C.A.,Federal University of Ouro Preto | Zorzal C.B.,Federal University of Ouro Preto | Coelho L.C.,Federal University of Ouro Preto | Oliveira M.S.,IFMG
Revista Escola de Minas | Year: 2011

This research addressed the effects of depressants on willemite flotation, in order to increase both zinc recovery and selectivity. The reagents were: an amine emulsion (Clariant Flotigan 2835-2L), diesel oil and MIBIC in the proportions of 1.0, 0.16 and 0.4 as the collector and frother; a sodium sulfide and sodium carbonate solution as the activator and pH modifier, respectively; sodium silicate as the dispersant agent; and as the depressant: sodium silicate, dextrin, potassium dichromate, tannin, starch and carboxymethylcellulose (CMC). The steps of dispersion, sulfidization and willemite flotation were investigated. This work was conducted on laboratory scale and showed, among other findings, that a good performance could be obtained using carboxymethylcellulose and starch as a dolomitic gangue depressant in the flotation of willemite zinc ore. Source

The species Helicoverpa armigera is one of the most important polyphagous and widely distributed pests in the world. Its occurrence was recently reported on soybean and cotton, in the states of Goiás, Mato Grosso and Bahia, Brazil. Tomato is also host species of H. armigera, among the 200 registered, being one of the most important crops in the Espírito Santo state. The production of tomatoes is fully dedicated for fresh consumption and the damage caused by H. armigera in fruits make unfeasible marketing. Therefore, this study aimed to record the occurrence of H. armigera in tomato crop in the Espírito Santo state. From February 2012 to October 2013, insects were collected from tomato plants in some producing areas. After insect identification, by dissection of the genitalia of adult moths, it was possible to confirm the occurrence of H. armigera on tomato crop in the Espírito Santo state. © 2015 Sociedade de Olericultura do Brasil. All rights reserved. Source

Moura R.S.,IFMG | Marujo D.,Federal University of Itajuba | Souza A.C.Z.,Federal University of Itajuba | Lopes B.I.L.,Federal University of Itajuba
IET Conference Publications | Year: 2013

This paper proposes a method to block voltage regulator action with the meaning to enlarge a system load margin. Local control actions seem to be effective for this purpose, but are dependent on the existence of local sources. On the other hand, sharing the voltage control with the help of multiple machines-control provide good results, which is associated to a secondary voltage control strategy. Voltage collapse problems, when triggered by successive load increases, may be flagged by some important signals. In this paper, the reactive power generation/voltage level relationship is monitored, so the reactive power is blocked in an upper level prior to voltage collapse occurrence. A small test system is employed to show the idea and others IEEE systems are used to test the methodology. Source

Fia R.,Federal University of Lavras | de Matos A.T.,Av. P.H. Rolfs | Fia F.R.L.,IFMG | de Matos M.P.,Av. P.H. Rolfs | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2010

Two winter grasses, ryegrass (Lolium multiflorum) and oats (Avena strigosa Schreb), were grown in constructed wetlands (SACs) used in the treatment of wastewater of coffee processing (ARC) with the aim to evaluate their agronomic performance. These forage crops were submitted to different organic loads (650 to 1500 kg ha-1 d-1 of COD), offered by the application of anaerobic effluent filters, used in the treatment of ARC. As a control treatment, the same plant species were grown in a Hoagland solution. The forage dry matter produced by over 53 days of monitoring SACs ranged from 7.4 to 14.0 and from 0.5 to 2.7 t ha-1, and the crude protein yield ranged from 1017 to 2187 and 66.6 to 316.8 kg ha-1 for ryegrass and oats, respectively. The results showed that, among the forages studied, the ryegrass was more suitable to be grown in SACs used in the post-treatment of ARC anaerobic effluent filters, presenting higher dry matter yield and crude protein, and therefore better adaptation to the system. Source

Faria P.B.,IFMT | Vieira J.O.,Total Alimentos | Silva J.N.,IFMT | Rodrigues A.Q.,IFMT | And 3 more authors.
Revista Brasileira de Ciencia Avicola | Year: 2011

The present study was carried out to evaluate the effects of alternative feedstuffs as partial substitutes of corn and soybean in free-range broiler diets on performance, carcass yield and technical-economic viability. A total of 400 Pescoço Pelado broilers were distributed in a completely randomized experimental design (CRD), with four treatments (treatment 1:Control; treatment 2: 10% rice bran inclusion; treatment 3: 10% ground cassava leaves; and treatment 4: 10% ground lead tree hay) with four replicates per treatment. Each replicate consisted of a group of 25 birds per paddock, separated per sex. Initial weight (IW), final weight (FW), body weight (BW), daily weight gain (DWG), feed intake (FI) and feed conversion ratio (FCR) were evaluated. Carcass, cuts (breast, thigh, drumstick, back, neck, leg and wings), abdominal fat and giblets (gizzard, heart and liver) yields were determined. The technical-economic viability of each treatment was assessed by determining the cost of feed per kg body weight, economic efficiency index and cost. The highest final weights were obtained with the use of rice bran. Rice bran and cassava leaves promoted higher carcass yield, as well as lower back and abdominal fat yields. The use of cassava leaves showed better economic efficiency among the treatments with alternative feedstuffs. The use of alternative feedstuffs at 10% inclusion in substitution of corn and soybean meal did not not result in major changes in performance and carcass parameters, and economic efficiency, and therefore, their use is recommended when the availability or the price of key ingredients, such as soybean meal and corn, increase. Source

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