Design responsivo do sistema Agritempo para multidispositivos.

Desta forma, este artigo apresenta o processo e as alterações realizadas no design da nova versão do Agritempo a fim de melhorar continuamente a experiência do usuário em novos dispositivos, resoluções e tecnologias

Penetrability of chloride ions in concrete protected by an acrylic painting

In order do decrease the penetrability of chloride ions in concrete the use of paintings based on polymers can be a good solution. The use of acrylic paintings is recommended because they have good resistance to ultraviolet radiation. It is important to quantify the decrease of chloride ions penetrability obtained by the use of this kind of paintings. The durability of the polymeric paintings is another aspect that needs to be analysed. In this study an acrylic painting was used to protect the concrete and decrease the penetrability of chloride ions. The concrete used was a C12/15, with a cement content of 280 kg/m3 and a water-cement ratio of 0.60. The acrylic painting was applied in concrete specimens 28 days after casting. In order to have a better protection we applied two coats separated by 5 hours. The penetrability of chloride ions was measured following the ASTM standard C 1202 – 94. Before the penetrability tests, some specimens were exposed to UV radiation. The exposition to the light occurred by cycles consisting of alternating periods of 8 hours of UV radiation at 60 ºC and 16 hours without UV radiation at 50 ºC. Three kinds of exposition were made consisting on 5, 10 and 15 cycles. The results showed always a high penetrability of chloride ions. This occurred because a poor concrete was used. The protection by an acrylic painting decreases the penetrability of chloride ions. The charge passed decreased about 32 %. However, is not possible to achieve low chloride ions penetrability only with the use of acrylic paintings. It is necessary also the use of a good concrete with low porosity. After the exposition to the UV radiation the penetrability of chlorides ions did not increase. It seems that the UV radiation does not affect the properties of the acrylic painting

Controle de plantas voluntárias de soja com herbicidas utilizados em milho.

O presente trabalho teve por objetivo avaliar a eficiência de diversos herbicidas no controle de plantas voluntárias de soja. O experimento foi conduzido em casa de vegetação, onde as unidades experimentais foram compostas de vasos de 10 dm3 de capacidade, dispostos em delineamento inteiramente casualizado em esquema fatorial 2 x 12, com quatro repetições. As cultivares Conquista e Valiosa RR® foram submetidas à aplicação dos herbicidas: atrazine (1.500 g ha-1), tembotrione (100 g ha-1), mesotrione (120 g ha-1), nicosulfuron (40 g ha-1), 2,4-D (670; 1.050 e 1.340 g ha-1), diquat (300 g ha-1), paraquat (400 g ha-1), [paraquat + diuron] (500 + 250 g ha-1) e glyphosate (1.500 g ha-1), além de uma testemunha sem aplicação. A aplicação foi realizada quando as plantas encontravam-se no estádio fenológico V3. Os herbicidas atrazine, glyphosate, [paraquat + diuron] e diquat apresentaram os maiores níveis de controle das plantas voluntárias de soja da variedade Conquista. Os herbicidas atrazine, [paraquat + diuron] e 2,4-D na dose de 1.340 g ha-1 foram os mais eficientes no controle das plantas voluntárias de soja da variedade Valiosa RR®. A suscetibilidade das plantas voluntárias de soja provenientes da variedade convencional (Conquista) e da variedade resistente ao glyphosate (Valiosa RR®) foi variável de acordo com o herbicida aplicado. Control of volunteer soybean plants with herbicides used in corn. This study aimed at evaluating the effectiveness of several herbicides on the control of volunteer soybean plants. The experiment was carried out in a greenhouse, where the experimental units were composed of vessels with 10 dm3 capacity, arranged in a completely randomized design, in a 2 x 12 factorial scheme, with four replications. The cultivars Conquista and Valiosa RR® underwent an application of the herbicides: atrazine (1.500 g ha-1), tembotrione (100 g ha-1), mesotrione (120 g ha-1), nicosulfuron (40 g ha-1), 2.4 D (670; 1,050 and 1,340 g ha-1), diquat (300 g ha-1), paraquat (400 g ha-1), [paraquat + diuron] (500 + 250 g ha-1), and glyphosate (1,500 g ha-1), besides an untreated control. The application was made when the plants were in the phenological stage V3. The herbicides atrazine, glyphosate, [paraquat + diuron] and diquat showed the highest control levels of the volunteer soybean plants of the variety Conquista. The herbicides atrazine, [paraquat + diuron] and 2.4-D at the dose of 1,340 g ha-1 were the most effective ones in controlling volunteer soybean plants of the cultivar Valiosa RR®. The susceptibility of the volunteer soybean plants from the conventional variety (Conquista) and the glyphosate-resistant variety (Valiosa RR®) was variable depending on the applied herbicide

Flexural tensile behaviour of enhanced performance concrete

High-performance concrete is generally produced using carefully selected high quality materials. These materials increase significantly the initial costs, hence, limiting its use. In this research work the performance of concrete was enhanced through incorporating low cost untreated materials like fly ash and crushed aggregates. Thus, it can be produced enhanced or even high performance low cost concrete and, also, decrease significantly the use of cement and non-renewable natural resources (river/sea sand), contributing to the necessary sustainability of construction. From experimental program, the effect of replacing cement by fly ash (up to 60%) in the flexural tensile behaviour was evaluated, using control compositions without the addition of fly ash as a base of comparison. The results obtained demonstrate that it is possible to produce enhanced performance concrete with the selected materials replacing up to 40% of the cement by fly ash. In specimens of such mixtures, cured at least 56 days, the values of the compressive strength and the flexural tensile parameters were similar to the ones of the control mixtures

Procedimiento de clasificación de morteros con incorporación de materiales de cambio de fase basado en el comportamiento mecánico, durabilidad y comportamiento térmico

Nowadays, considering the high variety of construction products, adequate material selection, based on their properties and function, becomes increasingly important. In this research, a ranking procedure developed by Czarnecki and Lukowski is applied in mortars with incorporation of phase change materials (PCM). The ranking procedure transforms experimental results of properties into one numerical value. The products can be classified according to their individual properties or even an optimized combination of different properties. The main purpose of this study was the ranking of mortars with incorporation of different contents of PCM based in different binders. Aerial lime, hydraulic lime, gypsum and cement were the binders studied. For each binder, three different mortars were developed. Reference mortars, mortars with incorporation of 40% of PCM and mortars with incorporation of 40% of PCM and 1% of fibers, were tested. Results show that the incorporation of PCM in mortars changes their global performance.Actualmente, existen varios productos de construcción, siendo importante una adecuada selección, con base en sus principales propiedades y funciones. En esta investigación se aplicó un procedimiento de clasificación desarrollado por Czarnecki y Lukowski, en morteros con incorporación de materiales de cambio de fase (PCM). Este procedimiento transforma los resultados experimentales de las propiedades en un único valor numérico. Los productos se clasifican de acuerdo con sus propiedades individuales o en una combinación optimizada de diferentes propiedades. El principal objetivo de este estudio fue la clasificación de morteros basado en los diferentes aglutinantes con incorporación de diferentes cantidades de PCM. Los aglutinantes utilizados fueran la cal aérea, cal hidráulica, yeso y cemento. Para cada aglutinante se han desarrollado tres morteros, siendo morteros de referencia, con incorporación de 40% de PCM y con incorporación de 40% de PCM y 1% de fibras. Fue observado que la incorporación de PCM en morteros cambia su comportamiento global

Comportamento à tracção em flexão de betões de desempenho melhorado

A substituição parcial de cimento por cinzas volantes tem sido utilizada por razões económicas e de trabalhabilidade da mistura. O conhecimento acerca da influência da idade e da percentagem de cinzas no comportamento em flexão do betão, principalmente na sua capacidade de absorção de energia, é reduzido. O presente trabalho pretende dar um contributo nesta área

Controle de plantas voluntárias de soja Roundup Ready.

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Weed phytosociological and floristic survey in agricultural areas of southwestern Goiás region.

The use of the Roundup Ready ® technology and the cultivation of a second cropinfluence the floristic composition of weed communities in Brazilian Central-West region cropping systems. This study has aimed to diagnose the dominant weed species in southwestern Goiás in areas of genetically-modified and conventional soybeans, using phytosociological and floristic surveys. Weed sampling was obtained by collecting all the plants present within a 0.5 m hollow frame, randomly thrown 20 times in each of thirty-five agricultural areas in the 2012/2013 harvest. Field survey was carried out in three periods: before desiccation for soybean sowing, before postemergence herbicide in soybean first application and before postemergence herbicide application in late harvest. A total of 525 m2 was inventoried and 3,219 weeds were collected, which included 79 species, 58 genera and 28 families. Families Poaceae, Asteraceae, Euphorbiaceae, Fabaceae, Amaranthaceae, were the most representative in the survey. Species Cenchrus echinatus, Glycine max, Chamaesyce hirta, Commelina benghalensis, and Alternanthera tenella stood out in importance. The RR+millet soybean treatment had the highest number of species (44), while the conventional soybean + sorghum treatment had the lowest number of species (18). The highest number of species was recorded in first sampling period. Treatments conventional soybean + maize and conventional soybean + millet showed higher similarity (70%), while treatments RR soybean + millet and conventional soybean + sorghum showed the least (51%). Species of difficult control were recorded in all cultivation systems analyzed

Artificial neural networks classify cotton genotypes for fiber length.

Fiber length is the main trait that needs to be improved in cotton. However, the presence of genotypes x environments interaction for this trait can hinder the recommendation of genotypes with greater length fibers. The aim of this study was to evaluate the adaptability and stability of the fibers length of cotton genotypes for recommendation to the Midwest and Northeast, using artificial neural networks (ANNs) and Eberhart and Russell method. Seven trials were carried out in the states of Ceará, Rio Grande do Norte, Goiás and Mato Grosso do Sul. Experimental design was a randomized block with four replications. Data were submitted to analysis of adaptability and stability through the Eberhart & Russell and ANNs methodologies. Based on these methods, the genotypes BRS Aroeira, CNPA CNPA 2009 42 and CNPA 2009 27 has better performance in unfavorable, general and favorable environment, respectively, for having fiber length above the overall mean of environments and high phenotypic stability

Biodiversity measures in agriculture using DNA.

Introduction; From nature to agriculture: why we need diversity?; Microrganisms and pests associated to plants; Genetic markers and molecular markers; How measures are taken: a brief review on the simplest and most popular tools; Random amplified DNA reveals polymorphism; Repetitive sequences can be especially polymorphic; Sequencing and single nucleotide polymorphism; Markers may help to understand evolution; The gains in plant breeding depends of variance; Conclusion