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The pyrolysis/devolatilization is a basic step of thermochemical processes and requires fundamental characterization. In this paper, the kinetic model of pyrolysis is specified as a one-step global reaction. This type of reaction is used to describe the thermal degradation of wheat straw samples by measuring rates of mass loss of solid matter at a linear increase in temperature. The mentioned experiments were carried out using a derivatograph in an open-air environment. The influence of different factors was investigated, such as particle size, humidity levels, and the heating rate in the kinetics of devolatilization. As the measured values of mass loss and temperature functions transform in Arrhenius coordinates, the results are shown in the form of saddle curves. Such characteristics cannot be approximated with one equation in the form of Arrhenius law. For use in numerical applications, transformed functions can be approximated by linear regression for three separate intervals. Analysis of measurement resulting in granulation and moisture content variations shows that these factors have no significant influence. Tests of heating rate variations confirm the significance of this impact, especially in warmer regions. The influence of this factor should be more precisely investigated as a general variable, which should be the topic of further experiments.

In comparison to coal, biomass is characterized by a higher content of volatile matter. It is a renewable source of energy which has many advantages from an ecological point of view. Understanding the physical phenomena of pyrolysis and representing them with a mathematical model is the primary step in the design of pyrolysis reactors. In the present study, an existing mathematical model is used to describe the pyrolysis of a single solid particle of biomass. It couples the heat transfer equations with the chemical kinetics equations.A finite difference method is used for solving the heat transfer equation and the two-step pyrolysis kinetics equations. The model equation is solved for a slab particle of equivalent dimension 0.001 m and temperature ranging from 300 to 923 K. An original numerical model for the pyrolysis of wood chips is proposed and relevant equations solved using original program realized in MATLAB.To check the validity of the numerical results, experimental results of pyrolysis of woody biomass in laboratory facility was used.The samples were heated over a range of temperature from 300 to 923 K with three different heating rates of 21, 32 and 55 K/min, and the weight loss was measured. The simulation results as well as the results obtained from thermal decomposition process indicate that the temperature peaks at maximum weight loss rate change with the increase in heating rate. The experimental results showed that the simulation results are in good agreement and can be successfully used to understand the degradation mechanism of solid reaction.

The objective of the present article is to present an experimental facility which was designed and built at the Faculty of Technical Sciences in order to study the combustion of different sorts of biomass and municipal solid waste. Despite its apparent simplicity, direct combustion is a complex process from a technological point of view. Conventional combustion equipment is not designed for burning agricultural residues. Devices for agricultural waste combustion are still in the development phase, which means that adequate design solution is presently not available at the world market. In order to construct a boiler and achieve optimal combustion conditions, it is necessary to develop a mathematical model for biomass combustion. Experimental facility can be used for the collection of data necessary for detailed modelling of real grate combustor of solid biomass fuels. Due to the complexity of the grate combustion process, its mathematical models and simulation software tools must be developed and verified using experimental data. This work highlights the properties required for the laboratory facility designed for the examination of biomass combustion and discusses design and operational issues.

Infectious bursal disease virus is an important poultry pathogen. It is distributed worldwide and causes significant economic losses. In this study, a system was adopted for the simultaneous monitoring of vaccine and virulent strains using reverse transcription polymerase chain reaction (RT-PCR). After the decay of maternal antibodies, chickens were vaccinated at the age of 37 days with a virus of intermediate virulence and challenged at 5, 10 and 14 days post vaccination (dpv). The challenge was done with IBDV strain CH/99. Sequencing of the hypervariable region of VP2 has shown that CH/99 belongs to the very virulent group of viruses. The vaccine virus could be found in the bursa of Fabricius, spleen, thymus and bone marrow until 24 dpv. The CH/99 challenge virus was found in the bursa and lymphoid organs when chickens were challenged at 5 and 10 dpv. When challenge was performed at 14 dpv, the pathogenic virus could not be found in the bursa and other lymphoid organs.

In the quarantines of the epyzootiological territory of Belgrade, feathers deriving from live and dead dehydrated exotic birds were samples. Birds were housed in closed disinfected bird shelter facilities with cages. Study was carried out in 4 quarantines of total 22, during 2010, and it included only 5 bird species, 3 birds of each species (Coracias cyanogaste, Acridothere tristis, S. canaria, Pycnonotus cafer and Tockus fasciatus). A total of 15 samples of feathers were analyzed. Samples were placed in the antibiotics solution, for 24 hours at room temperature, and subsequently cultivated on Sabouraud dextrose agar and Potato dextrose agar, in aerobic conditions in the darkness at the temperature of in 37°C duration of 5 days, and 3-4 weeks at 20±2 ºC (Scopulariopsis spp.), and in aerobic conditions at room temperature of 20±2 ºC for 5 days (Aspergillus spp., Penicillum spp. and Fusarium spp.) The presence of Scopulariopsis spp., Aspergillus spp., Penicillum spp. and Fusarium spp. was identified. The study showed that commonly healthy birds, as well as dead birds, which died mainly due to exhaustion and dehydration during transportation, can carry various fungi/moulds which contaminate the air, soil and water surrounding their habitats. Most of these birds are sold as closed domesticated pets which are clinically healthy birds, however, they can be important source of potentially pathogen causers which they carry on their body. This finding of fungal species on the body/feathers of birds are naturally suitable place for their transmission, and this also contributes to better understanding of the nature and occurrence of many wide spread diseases in transmiting mycoses.

In the present experiment, the presence of mycological agents in chickens with skin lesions on foot pads was investigated, in order to improve the health of broiler chickens. Foot-pad dermatitis (FPD) is described in the literature as dermatitis caused by multifactor causes. The presence of irritating chemical substances in the litter, genetic predispositions of hybrids, immune suppressive diseases of chickens, as well as the composition of commercial broiler diets that influence the occurrence of wet litter, are proven factors that contribute to a more intensive incidence of foot-pad dermatitis. Foot-pad dermatitis is a condition characterised by lesions on metatarsal and digital ventral skin of poultry feet. It is type of contact dermatitis which in severe cases shows slower weight gain, poor health condition and welfare. Taking into consideration the literature data, chickens reared in closed facilities where the bacterial and mycological agents are present partly in the litter if not properly disinfected, but also in the food or the chicken plumage, we wanted to investigate their presence in the skin of foot pads. The study was focused on incidence of foot-pad dermatitis in 500 one day old broiler chickens of Hubbard genotype, in two feeding (standard/economical) programs for broilers available on our market. Chopped straw was used as litter. At the end of fattening, all chickens were examined for the presence of lesions on the skin of the feet. Total of 39 chickens were allocated to the intensity of the lesion on foot pads rated as 2 (mild) and 3 (severe). In the mycological examination of the 9 samples of autoclaved chicken legs with lesions on the feet, we have isolated and identified the presence of fungi /mould Aspergillus fumigatus. The histopathology investigation, during which the tissue section from mild and severe skin foot pads was collected and stained using Hematoxylin and eosin, revealed the hyperkeratosis, panniculitis, ballooning degeneration and dermis inflammation. No fungal elements were observed in the sections of pads stained with Gomori methenamine silver. Birds are especially susceptible to infection with Aspergillus fumigatus. That species of fungus is also classified as allergenic factor.