The current paper investigates the effects of geometric design parameters on the fatigue failure of the drive axle housing using the Finite Element Method (FEM). The study examines the effects of various factors on the fatigue life of the drive axle housing, such as axle housing wall thickness, housing cross-sectional rounding radius, and rounding radius of the central part of the housing. Based on the known material properties and dynamic loads, a CAD/FEM model of the drive axle housing was developed, and a structural analysis was carried out. Based on the results of the structural analysis, critical places on the housing were determined, and fatigue analysis and lifetime prediction were performed. Through a series of simulations, the study reveals that increasing housing wall thickness can significantly improve fatigue performance. Similarly, increasing the rounding radius at the housing cross-section, as well as the rounding radius at the central part of the housing can also lead to improved fatigue performance. However, the effect of increasing the value of these two radii is not as significant as the effect of the wall thickness. These findings give useful information regarding the design and manufacture of drive axle housings for vehicles, intending to reduce the likelihood of fatigue failure.

We study the local dynamics and global character of third-order polynomial difference in the first octant of initial conditions with infinite number of prime period-three solutions (three cycles). It is also presented the case when the observed difference equation may be extended to the whole ℝ𝟑.

In this paper, we observed the ordinary differential equation (ODE) system and determined the equilibrium points. To characterize them, we used the existing theory developed to visualize the behavior of the system. We describe the bifurcation that appears, which is characteristic of higher-dimensional systems, that is when a fixed point loses its stability without colliding with other points. Although it is difficult to determine the whole series of bifurcations that lead to chaos, we can say that it is a common opinion that it is precisely the Hopf bifurcation that leads to chaos when it comes to situations that occur in applications. Here, subcritical and supercritical bifurcation occurs, and we can say that subcritical bifurcation represents a much more dramatic situation and is potentially more dangerous than supercritical bifurcation, technically speaking. Namely, bifurcations or trajectories jump to a distant attractor, which can be a fixed point, limit cycle, infinity, or in spaces with three or more dimensions, a foreign attractor.

In this work, various combinations of the NO emission influencing factors and their x combined effects in air staging combustion on level of furnace, using over fire air, were investigated in an experimental lab-scale furnace. At this, process temperature were varied in the range from 950?C to 1450?C, excess air ratio in primary zone in the range ? = 0.9 - 1.2, while distance of over fire air nozzles from the burner outlet varied until a 1 given distance of 2/5 of total length of furnace. Basic fuel is brown coal from Middle Bosnia coal basin, mixed in two coal blends and one coal-woody biomass blend, to combine an effect of fuel characteristics variation on NO emission. Results shows that x an average reduction of NO emission over tested temperature range, when using over x fire air against conventional air supply with over fire air switched off, is 26.5%. At this, much more NO emission reduction for two coal blends were occurred at higher x temperatures ? at 1350?C and above, where an average NO emission reduction is x 32.5%. Furthermore, it was found that the NO emission decreased with an increase in x distance of over fire air nozzles from the outlet level of burner until a distance of 1/3 of total furnace length; with further increase of the distance, NOx emission is stabilised and no further effect to NOx emission reduction was observed, while CO emission and unburnt increased.

In this work, various combinations of the NO emission influencing factors and their x combined effects in air staging combustion on level of furnace, using over fire air, were investigated in an experimental lab-scale furnace. At this, process temperature were o o varied in the range from 950 C to 1450 C, excess air ratio in primary zone in the range λ = 0.9 1.2, while distance of over fire air nozzles from the burner outlet varied until a 1 given distance of 2/5 of total length of furnace. Basic fuel is brown coal from Middle Bosnia coal basin, mixed in two coal blends and one coal-woody biomass blend, to combine an effect of fuel characteristics variation on NO emission. Results shows that x an average reduction of NO emission over tested temperature range, when using over x fire air against conventional air supply with over fire air switched off, is 26.5%. At this, much more NO emission reduction for two coal blends were occurred at higher x o temperatures – at 1350 C and above, where an average NO emission reduction is x 32.5%. Furthermore, it was found that the NO emission decreased with an increase in x distance of over fire air nozzles from the outlet level of burner until a distance of 1/3 of total furnace length; with further increase of the distance, NO emission is stabilised and x no further effect to NO emission reduction was observed, while CO emission and x unburnt increased.

This paper presents a research on ash-related problems and emissions during co-firing low-rank Bosnian coals with different kinds of biomass; in this case woody sawdust and herbaceous energy crops Miscanthus. An entrained-flow drop tube furnace was used for the tests, varying fuel portions at a high co-firing ratio up to 30%wt woody sawdust and 10%wt Miscanthus in a fuel blend. The tests were supposed to optimize the process temperature, air distribution (including OFA) and fuel distributions (reburning) as function of SO2 and NOx emissions as well as efficiency of combustion process estimated through the ash deposits behaviors, CO emissions and unburnt. The results for 12 co-firing fuel combinations impose a reasonable expectation that the coal/biomass/Miscanthus blends could be successfully run under certain conditions not producing any serious ash-related problems. SO2 emissions were slightly higher when higher content of woody biomass was used. Oppositely, higher Miscanthus percentage in the fuel mix slightly decreases SO2 emissions. NOx emissions generally decrease with an increase of biomass co-firing rate. The study suggests that co-firing Bosnian coals with woody sawdust and Miscanthus shows promise at higher co-firing ratios for pulverized combustion, giving some directions for further works in co-firing similar multi-fuel combinations.

Co-firing coal with different types of biomass is increasingly being applied in thermal power plants in Europe. The main motive for the use of biomass as the second fuel in coal-fired power plants is the reduction of CO 2 emissions, and related financial benefits in accordance with the relevant international regulations and agreements. Likewise, the application of primary measures in the combustion chamber, which also includes air staging and/or reburning, results in a significant reduction in emission of polluting components of flue gases, in particular NO x emissions. In addition to being efficient and their application to new and future thermoblocks is practically unavoidable, their application and existing conventional combustion chamber does not require significant constructional interventions and is therefore relatively inexpensive. In this work results of experimental research of co-firing coals from Middle Bosnian basin with waste woody biomass are presented. Previously formed fuel test matrix is subjected to pulverized combustion under various temperatures and various technical and technological conditions. First of all it refers to the different mass ratio of fuel components in the mixture, the overall coefficient of excess air and to the application of air staging and/or reburning. Analysis of the emissions of components of the flue gases are presented and discussed. The impact of fuel composition and process temperature on the values of the emissions of components of the flue gas is determined. Additionally, it is shown that other primary measures in the combustion chamber are resulting in more or less positive effects in terms of reducing emissions of certain components of the flue gases into the environment. Thus, for example, the emission of NO x of 989 mg/ measured in conventional combustion, with the simultaneous application of air staging and reburning is reduced to 782 mg/, or by about 21%. The effects of the primary measures applied in the combustion chamber are compared and quantified with regard to conventional combustion of coals from Middle Bosnian basin. Article History : Received: November 5 th 2017; Revised: Januari 6th 2018; Accepted: February 1 st 2018; Available online How to Cite This Article : Hodžic, N., Kazagic, A., and Metovic, S. (2018) Experimental Investigation of Co-Firing of Coal with Woody Biomass in Air Staging and Reburning. International Journal of Renewable Energy Development, 7(1), 1-6. https://doi.org/10.14710/ijred.7.1.1-6

More than half of the world's electricity is produced by burning large amounts of coal in thermal power plants and at the same time producing huge quantities of coal ash. Hydraulic transportation of coal ash from coal fired thermal power plants to ash ponds, using high concentration slurry disposal systems (HCSD) is safe, reliable, economical and attractive method due to its low maintenance costs, round the year availability and being environmentally friendly. Present study reports simulated pressure drop for the flow of high concentration fly ash slurries (in the range of 50 70 % by weight) through sudden and conical pipe contractions at various flow velocities using available experimentally obtained rheological parameters. For calculations the finite volume method is applied, which is the most commonly used and gives very good results in the analysis of problems in fluid mechanics and heat transfer. The method in this paper is adapted for simulation of flow of viscoplastic materials whose behavior is described by viscoplastic (Bingham) model. The simulation results are compared with corresponding analytical solutions and experimental data and good agreement between the results is shown.

Energy conversion from fossil fuels usually begins with combustion processes accompanied by series of technical and technological problems and very often produces significant amount of pollution. Problems are often encountered in cases of combustion of low ranking, low-reactive and deposition tending coals, like some of those exploited in Bosnia and Herzegovina. Because of these reasons, it is necessary to develop new and improve existing technologies of low pollution combustion, not enough investigated so far, especially in cases when low ranking coals are used. In this regard, the pulse combustion offers good possibilities. Additionally, the pulse combustion could be applied as auxiliary method in existing large-scale boilers as a cleaning device of outer heating surfaces. In this paper, the most recent results obtained from experimental work at Mechanical Engineering Faculty in Sarajevo are presented. 1. INTRODUCTION, [3] About 80 % of primary energy spent in the world is obtained from fossil fuels. Such situation, where energy needs are dominantly met by conversion of primary energy from fossil fuels, will continue also in the future. Bosnia and Herzegovina (BIH) is not a exception. It is well known that coals are most used fossil fuel. About 75 % of all worlds fossil fuel reserves are coals (Figure 1). It is estimated that with today's level of energy consumption the coal reserves are sufficient for next 200 years. Additionally, the coal reserves are more uniformly situated then the petrol reserves. Because of the rapid decrease of the petrol natural gas reserves, importance of the coal as energy source will probably rise in the future. On the other side, reserves of high quality coal are also decreasing and need to exploit low quality coals is more pronounced. In the process of conversion of the primary energy from fossil fuels combustion is the most important part with a variety of technical and technological problems and it is always potential source of pollution. Probability that problems will occur during a combustion process depends on a series of variables, but these problem occur more often during combustion of low ranking, low-reactive and deposition tending coals, like some of those exploited in BIH. There are very important deposits of lignite and brown coals in BIH, but there is no any stone coal. Due to last estimations, there are about 4⋅10 9 tones of coal, where 40 % are brown coals and 60 % is lignite. The quality of coals …