The design and execution of a laboratory micro hydroelectric power plant

The paper presents a laboratory micro hydroelectric power plant destined to applicative activities. The hydraulic turbine is a Pelton turbine, rebuilt by fast prototyping in Geomagic Design X and printed on a 3 D printer. The turbine casing and the afferent elements are made in-house. The hydrogenator is synchronous being an alternator from a Dacia vehicle. The hydrogenerator load is constituted by 3 groups of light bulbs. We analysed the working of the micro-hydroelectric power plant in idle run and for different loads. As a result of the analysis we found out that it stably works for different loads and by its open construction it is useful for developing students’ ability to understand the phenomena. The installation designed and executed is useful for the engineering students as the pandemic forbids the thematical visits in hydro-energetic facilities.

The contribution of statistical processes in the control of technological processes

In this paper, a manufacturing process is analyzed, having as quality characteristic the “height of the screw head”, using analyzes and representative diagrams. Based on this case study, the way to solve these types of problems using the Quality Control Chart module of the WinQSB program, as well as the XLSTAT program is presented.

An assessment of physical properties and water holding capacity of soil under different fertilizer applications

This study was carried out at the Teaching and Research Farm of the Department of Agricultural and Bio-Environmental Engineering, School of Engineering, The Federal Polytechnic, Ado-Ekiti to evaluate the water holding capacities of soil under different fertilizers. The experiment was laid out in randomized complete block design (RCBD). The treatments: control, poultry waste, biochar and urea fertilizer replicated four times were incorporated into the soil and maize seed planted. Data collected were subjected to statistical analysis. Soil samples were analyzed for moisture contents, bulk densities, particle densities and water holding capacities. Maize yield was also analyzed. The result obtained showed a significant (p< 0.05) changes in maize yield for the different fertilizers. It also shows a non-significant (p<0.05) effect on water holding capacities of the soils incorporated with different fertilizers. The study concluded that fertilizers has no effect on the water holding capacity of the soil and that poultry waste amended soil will produce higher yield.

An overview about the feasibility of the hydrogen power plants

In order to make the decision to implement a project from any domain, several aspects must be analyzed in the preliminary stage, leading to the justification of the practical realization of the project. Feasibility is based on technical-economic criteria but also involves other impact factors, such as social and ecological. In the case of hydrogen, there are not many countries with experience in the field, but in the future it is expected that hydrogen technologies will expand, from production, transport, storage, distribution and use. There are more and more factors that encourage the development of hydrogen projects and the funding proposed through European environmental agreements is a real challenge for specialists. Therefore, the authors of the paper aimed to analyze several aspects of the feasibility of hydrogen production and storage projects with the identification of implementation conditions: benefits, efficiency, costs, sources of funding, entities involved, constraints or legislative framework.

Natural frequencies and mode shapes in zero-force members of a truss

Trusses are everywhere; they are used in bridges, antenna towers, cranes, even in parts of the International Space Station. And for good reason, they allow us to create strong structures while using materials in very efficient and cost-effective way. Trusses it is essentially a rigid structure made up of a collection of straight members. The type of truss depends on how the horizontal and diagonal beams are arranged.

Statistical analysis of measured wind speed data’s appealing spreadsheet applications

Once the wind data is measured, the values are processed, based on statistic approach, as accurately as possible, to provide a clear over-view of the locations wind potential, being the basis of any wind farm project, representing the go or no-go in further subsequent design steps. The probability density distributions are derived from time-series data, identifying the associated distributional parameters. The wind energy potential of the locations is studied based on the Rayleigh and Weibull models, implemented with the help of Excel computations, and representing tools, to understand the wind characteristics. Based on the statistical analysis of wind conditions presented here, the results of current study can be used to make a sustainable energy yield for any location.

Aspects about bouncing of plough caused by random

In this paper the author deals aspects about the vertical motion (named bouncing) of a tractor with plough mounted on the rear frame, during displacement over the random excitation surface of the agricultural land. Final results of the simulation process, performed on the model of tractor-plough with 3 degree of freedoms, show the difference between digging depth function as velocity motion and longitudinal profile of the terrain. Thus, the deviation of the plough depth from the reference depth is evaluated.

Dynamic modeling of defective gears

The use of geared transmissions has a long history and a rich experience, which has allowed the development of an intense research activity that has led to modern design methods, mostly standardized and execution technologies that have become traditional. As the fundamental sciences have provided more and more in-depth and refined knowledge, namely performance algorithms of optimal synthesis, the design in the field of gear transmissions has evolved by integrating in the calculation methods a growing number of elements. of influence (materials, geometry, dimensional and shape deviations, heat treatments, kinematic, energetic, dynamic factors, etc.). Automated modeling and simulation currently allow the prediction of behavior - from all points of view of a transmission - during operation.

Acoustic emission as a valuable technique used for monitoring polymer failures

In the paper, acoustic emission (AE) system was presented as a method that can be used to monitor polymer material failures. Samples fabricated of two aluminum profiles bonded together with a thick layer of cured epoxy resin were subjected to fracture tests. Epidian 53 epoxy resin cured with Z1 curing agent as well as Epidian 5 epoxy resin cured with PAC curing agent were selected as adhesives. Acoustic emission parameters were acquired during Double Cantilever Beam (DCB) tests. The frequencies of elastic waves released during failure were then analyzed using both Fast Fourier Transformation (FFT) and Wavelet Transformation (WT) for the two materials.

Dimensionless wave numbers evolution of a three spans simply supported beam when the intermediate supports are moving along the whole beam

Continuous beams simply supported with several intermediate supports are very common in engineering achievements everywhere. The paper shows the evolution of the dimensionless wave number in 3D format, respectively of the eigenfrequencies for a continuous beam with three openings when the intermediate supports take any position inside the beam. The frequency equation for calculating the dimensionless wave number is presented and the modal function is given with an example for the case where the eigenfrequency has the maximum value at fist vibration mode.