Cecília de Fátima Souza

Potencial da cinza do bagaço da cana-de-açúcar como material de substituição parcial de cimento Portland

This study is focused on the evaluation of the effects of the partial replacement of Portland cement by sugarcane bagasse ash (CBC) in mortars. The main objective was to find a suitable destination for an agricultural residue generated in an increasing amount in Brazil, as a result of the boom of the use of ethanol as an alternative fuel to gasoline. Also, the use of CBC as a mineral admixture in mortars and concretes contributes to a decrease in the environmental impact of these materials related to cement production. Experimental techniques were applied both for the CBC characterization and for the evaluation of its use as a mineral admixture in mortars, based on mechanical and physical tests. The yield of CBC from sugarcane bagasse burning was 10% (weight basis). The CBC presented a SiO2 content of 84% and a carbon content of 5%. Silica presented both amorphous and crystalline (cristobalite and quartz) structure. The pozzolanicity index applied indicates the reactivity of the CBC. Concerning the compression strength, the results from tests with mortars with up to 30% of CBC content indicated the viability of the partial substitution of cement by up to 20% of the CBC considered.

Comportamento de variáveis climáticas em sistemas de ventilação mínima para produção de pintos de corte

During the creation process of poultry, the initial or heating phase, is characterized as the most delicate period due to physiological immaturity of the birds. Thus, environmental factors stand out to infer, directly, in the growth, on the performance and maintenance of life of these animals. Based on these considerations, the aim of this study was to study the effect of three different systems of minimum ventilation (positive pressure, negative and natural) on environmental variables (air temperature, relative humidity and wind velocity) of broiler sheds during the heating phase. According to results obtained, it was verified that the heating system used was inadequate to maintain the air temperature and relative humidity within the standards deemed appropriate, thus exposing the birds to periods of heat stress by cold. In contrast, there were negative influences regarding ventilation rates applied to the two ventilation systems positive and negative. Wind velocity also remained at levels considered non-stressful for young chickens.

Segurança, saúde e ergonomia de trabalhadores em galpões de frangos de corte equipados com diferentes sistemas de abastecimento de ração

The feed supply in poultry houses can be done manually or automatically, to require effort is believed that manual supply could expose the attendant to physical overload. Thus, the objective of this study was to evaluate the ergonomic factors, and effect on posture and biomechanics of workers in poultry houses equipped with manual or automatic feeder. The analyzed factors were: physical work load, thermal environment, noise, lighting, postural analysis and biomechanics. It was found that in the sheds where the food supply system was manual, workers were exposed to greater physical effort. Based on the thermal environment management it was considered heavy for the two supply systems. The postures used in most activities deserve immediate corrective action. The handling in sheds equipped with manual feeder exposes workers to risk of injury in the shoulder, elbow, back, hip, knee and ankle. Thus, it can be concluded that management in poultry facilities equipped with manual feeder can be considered detrimental to the attendant exposing him to health risks and body damage.

Potential of production of biogas from the castor bean (Ricinus communis L.) cake

The study of the potential for biogas production, for a particular residue, is very important, especially for the design of digesters and it has been doing for a long time. However, there are few studies related to the anaerobic digestion of the castor bean cake (CBC). Then, the aim of this study was to determine the potential of biogas production from the digestion of the CBC, with and without addition of animal wastes. The experiment was carried out at the Department of Agricultural Engineering, Federal University of Vicosa. There were used nine bench digesters operating in batch way, containing 2 L of substrate. The three treatments were: CBC and water (A), CBC added with cow manure and water (B) and CBC added with swine manure and water (C). All treatments started at 9 dag kg -1 of Total Solids (TS) and three replications. The amount of manure applied corresponded to 15%, by weight, of the substrate TS. The experiment was finished after 56 days of digestion and it were carried out the TS analysis in three biofertilizers obtained. The treatment B showed the greatest potential to produce biogas, which were: 1.01 L L -1 of substrate, 3.18 L kg -1 TSreduced and 11.90 L kg -1 of CBC; in the treatment A it were: 0.55 L L -1 of substrate, 3.11 L kg -1 TSreduced, 5.50 L kg -1 of CBC; and in the treatment C it were: 0.50 L L -1 of substrate, 1.54 L kg -1 of TSreduced 5.91 L kg -1 of CBC. It was concluded that adding cow manure to castor bean cake in the process of digestion, result an increase in the biogas production potential and that this can be considered on the design of digesters.

BIOG-C: Modeling the volumetric methane production in the anaerobic digestion process applied to swine wastes

The implementation of models to forecast the occurrence of phenomena, especially the long-term ones, is a very important tool, since the time consumed in field experiments may be greatly reduced. The models cannot replace the experiments, but complement them. It is possible with modeling to consider a large number of factors that affect a particular process and their combinations, which would be impossible in conventional experiments. The first models for the anaerobic digestion process of animal wastes were reported in 1974, however, these models required many kinetic parameters. The aim of this work was to model volumetric production of methane from swine wastes, based on a bacterial growth kinetic model modified by Chen and Hashimoto (1979), using the results from laboratory experiments and literature data. The main variables were the bacteria specific growth rate, the effluent volatile solids concentration, the hydraulic retention time, the temperature, and the substrate mixing. The simulation was accomplished using “Modelmaker” software, version 2.0-SB technology (1994). The substrate temperatures imposed ranged from 25 to 40oC, hydraulic retention times ranged from 10 to 30 days, and the simulation of methane production rate was made for a 150 day period. The volumetric methane production was satisfactorily estimated by that model, called BIOG-C. It was noted that the methane production pattern was significantly controlled by the effluent volatile solids concentration. The model was tested by comparing the error correlation between the observed volumetric methane production obtained under similar conditions and those predicted by the model. The comparisons showed a close agreement.

Evaluation of the Physical Load and Biomechanics Conditions of Workers in Poultry Houses

Currently, Brazil has stood out to the world market for poultry production. However, beyond the concern with the handling of animals, Brazil is a pioneer in the quest for the welfare of workers in the agricultural sector. Looking diagnose the working conditions for the creation of broilers, the aim of this work was to evaluate the biomechanics conditions and physical demands of work of employees in poultry facilities equipped with automatic or hang up manual feeders. To determine the physical effort it was used a heart rate meter Polar Electro, composed by a digital receiver, an elastic band and a sensor transmitter placed on the workers`s chest. Biomechanical analysis was based on photographic records made with the employees at various angles in addition to the charges involved on a specific activity, which were used as input on the computational two-dimensional biomechanical model for predicting postures. With these data it was observed that the physical load of the employees at the facilities equipped with manual feeders were classified as moderately heavy, while in that ones equipped with automatic feeders the cardiovascular load was classified as mild. With respect to biomechanics, in the facilities with manual feeders, workers were exposed to risk of injury in the shoulder, elbow, back, hip, knee and ankle. Thus, it appears that the facilities equipped with manual feeders are considered unhealthy to workers.

Requisitos para credibilidade da análise sensorial do café

This research to determine the minimum amount of testers was made to ensure the reliability of the sensory analysis of the coffee beverages. It were analyzed the scores assigned by three Q-grader who adopted the international rules from the Cup of Excellence (CoE) methodology. Based on descriptive statistics of the scores the testers assigned to eight sensorial characteristics of different samples for Red and Yellow Catuaí coffees, at the ripe coffee cherry produced in altitudes below and above 900 meters, it was concluded that the most important fact is not on the number of testers involved, but rather on the reliability of the scores they assign. Therefore, the reliability is a measure directly related to the homogeneity for the set of scores assigned by different testers, given the same condition for the evaluation.

Climate change does not impacts on Coffea arabica yield in Brazil

BACKGROUND Brazil is the largest producer of coffee in the world. Studies on climate change estimate large impacts on production of Coffea arabica (C. arabica). In this context, it is necessary to know the quantitative production values to provide evidence for policy makers to target the prompt answer. RESULTS Using data from 18 municipalities located in five Brazilian States that produce more coffee in Brazil, in an unprecedented way, in this work it is shown that although the minimum temperature is the most important climatic variable for the production, its effect, although positive, and its degree of explanation, were technically too small to explain the volume of production in Brazilian conditions. According to the model of non-stationary time series ARIMA (1, 1, 0) the coffee production in the future may reach almost four million tons, and the productivity almost 2,500 kg ha-1 on average, being the advancement of technology the main factor that should promote the simultaneous increases in production and productivity. However, despite the natural climate variations, which make it the most responsible for the variability of annual coffee production, the producer must increase the use of the technologies to support the Brazilian coffee agribusiness. CONCLUSIONS The results of this study reveal that the coffee production in Brazil is much more due to productivity than to the minimum ambient temperature change over the long term, despite this climate variable be considered the most influential on the production and productivity of coffee.

NOTA TÉCNICA: PRODUÇÃO DE BIOGÁS E BIOFERTILIZANTE A PARTIR DA BIODIGESTÃO DA TORTA DE MAMONA COM ADIÇÃO DEJETOS DE ANIMAIS

The objective of this research was to quantify the production of biogas, characterize the biofertilizer, resulting from anaerobic digestion of castor bean cake, with and without manure. Bench digesters were operated in batch, containing 2 L of substrate. The three treatments were: castor bean cake with addition of bovine manure and water (T2), castor bean cake with the addition of swine manure and water (T3), with 9 dag kg-1 and ST with three replications. The amount of slurry applied corresponded to 15% of weight of ST substrate. The highest biogas production was observed in T2 (2.03 L), being similar in T1 and T3 (P> 0.05). The biofertilizer T1 showed the highest concentration of Nitrogen (6.13 g L-1). The phosphorus content was greater in T3 (867.80 mg L-1) and pH values, potassium and sodium were similar for all three treatments. The potential of biogas production were higher in T2. It was concluded that the castor bean is a good substrate for the production of biogas and biofertilizer with satisfactory chemical qualities, being observed increase production of this gas when associated with cattle manure.

Characterization and analysis of two types of reused broiler litter

The objective of this work was to characterize two different types of broiler litter material (coffee husks and wood shavings) that are commonly used in the Brazilian poultry industry within the State of Minas Gerais, and to evaluate the effect of their reuse on flock performance and physical and sanitary qualities of the litter. A second objective was to determine if the optimal number of reuses, based a sanitary point of view, matches that used for litter field composting, according to the results obtained by Marin (2011). The study was conducted with litter from 32 different broiler houses. Variables measured included litter moisture content, pH level, the incidence of foot pad dermatitis in birds, the sanitary quality through assessments to identify the bacteria Escherichia coli and Salmonella spp., and productive performance of birds.