scholarly journals Small-scale experimental tests of tandem mirror machines with thermal barriers

1979 ◽  
Author(s):  
R.P. Drake
2020 ◽  
Vol 12 (21) ◽  
pp. 9300
Author(s):  
David Alfonso-Solar ◽  
Carlos Vargas-Salgado ◽  
Carlos Sánchez-Díaz ◽  
Elías Hurtado-Pérez

Applications of renewable electricity in cities are mostly limited to photovoltaics, and they need other renewable sources, batteries, and the grid to guarantee reliability. This paper proposes a hybrid system, combining biomass and photovoltaics, to supply electricity to educational buildings. This system is reliable and provides at least 50% of electricity based on renewable sources. Buildings with small (<500 kW) installed power based on renewables, mainly biomass, are usually expensive. Besides, in urban areas, photovoltaic capacity is limited due to roof availability. This paper analyzes different configurations, meeting these constraints to obtain an economically feasible solution based on photovoltaic-biomass modelling of small size hybrid systems. The technology used for biomass energy valorization is a fluidized bed gasification power plant, which has been modelled with real data obtained from experimental tests and previous research projects. Thereby, real costs and electric efficiency are included in the model. The techno-economic feasibility analysis using HOMER software with metered real load curves from an educational building has been modelled. The results of the model show that hybrid renewable systems are very feasible in the scenario of 50% of electricity contribution, however, higher contribution (>70%) implies high electricity costs.


Author(s):  
Nara Oliveira ◽  
Theodoro Netto

The collapse pressure of pipelines containing corrosion defects is usually predicted by deterministic methods, either numerically or through empirical formulations. The severity of each individual corrosion defect can be determined by comparing the differential pressure during operation with the estimated collapse pressure. A simple deterministic procedure for estimating the collapse pressure of pipes with narrow and long defects has been recently proposed by Netto (2010). This formulation was based on a combined small-scale experimental program and nonlinear numerical analyses accounting for different materials and defect geometries. However, loads and resistance parameters have uncertainties which define the basic reliability problem. These uncertainties are mailyrelated to the geometric and material parameters of the pipe and the operational conditions. This paper presents additional experimental tests on corroded pipes under external pressure. The collapse pressure calculated using the equation proposed by Netto (2010) is compared with this new set of experiments and also with test results available in open literature. These results are used to estimate the equation uncertainty. Finally, a sensitivity analysis is performed to identify how geometric parameters of the defects influence the reduction of collapse pressure.


Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4530 ◽  
Author(s):  
Gabriel Talero ◽  
Camilo Bayona-Roa ◽  
Giovanny Muñoz ◽  
Miguel Galindo ◽  
Vladimir Silva ◽  
...  

Aeronautic transport is a leading energy consumer that strongly contributes to greenhouse gas emissions due to a significant dependency on fossil fuels. Biodiesel, a substitution of conventional fuels, is considered as an alternative fuel for aircrafts and power generation turbine engines. Unfortunately, experimentation has been mostly limited to small scale turbines, and technical challenges remain open regarding operational safety. The current study presents the facility, the instrumentation, and the measured results of experimental tests in a 640 kW full-scale J69-T-25A turbojet engine, operating with blends of Jet A1 and oil palm biodiesel with volume contents from 0% to 10% at different load regimes. Findings are related to the fuel injection system, the engine thrust, and the emissions. The thrust force and the exhaust gas temperature do not expose a significant variation in all the operation regimes with the utilization of up to 10% volume content of biodiesel. A maximum increase of 36% in fuel consumption and 11% in injection pressure are observed at idle operation between B0 and B10. A reduction of the CO and HC emissions is also registered with a maximum variation at the cruise regime (80% Revolutions Per Minute—RPM).


Author(s):  
Saeed Hajiahmadi ◽  
Majid Elyasi ◽  
Mohsen Shakeri

AbstractIn this research, geometric parameters were given in dimensionless form by the Buckingham pi dimensional analysis method, and a series of dimensionless groups were found for deep drawing of the round cup. To find the best group of dimensionless geometric parameters, three scales are evaluated by commercial FE software. After analyzing all effective geometric parameters, a fittest relational model of dimensionless parameters is found. St12 sheet metals were used for experimental validation, which were formed at room temperature. In addition, results and response parameters were compared in the simulation process, experimental tests, and proposed dimensionless models. By looking at the results, it very well may be inferred that geometric qualities of a large scale can be predicted with a small scale by utilizing the proposed dimensionless model. Comparison of the outcomes for dimensionless models and experimental tests shows that the proposed dimensionless models have fine precision in determining geometrical parameters and drawing force estimation. Moreover, generalizing proposed dimensionless model was applied to ensure the estimating precision of geometric values in larger scales by smaller scales.


Universe ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 4 ◽  
Author(s):  
Antonios Leisos ◽  
Apostolos Tsirigotis ◽  
George Bourlis ◽  
Michael Petropoulos ◽  
Leonidas Xiros ◽  
...  

The HELYCON project aims at the installation of cosmic air-shower detectors on the roofs of high-school buildings in western Greece. During the last four years, the HELYCON project made a substantial progress. Three HELYCON stations were installed and are still in operation at the Hellenic Open University (HOU) campus, while a small-scale air-shower detector ( μ Cosmics detector), suitable for in classroom operation, was developed. During the construction and operation of these detectors, many experimental tests and calibration procedures were established, offering the framework for the educational activities of the HELYCON project. In this work, we present the recent developments of the HELYCON project and describe the main aspects of the methodology we use in a five-day training program that introduces the Greek education community to the experimental procedures of HELYCON.


2020 ◽  
Vol 8 (12) ◽  
pp. 969
Author(s):  
Nicolo’ Lombardi ◽  
Stephanie Ordonez-Sanchez ◽  
Stefania Zanforlin ◽  
Cameron Johnstone

Tidal turbine array optimization is crucial for the further development of the marine sector. It has already been observed that tidal turbines within an array can be heavily affected by excessive aerodynamic interference, thus leading to performance deterioration. Small-scale experimental tests aimed at understanding the physical mechanisms of interaction and identifying optimal distances between machines can be found in the literature. However, often, the relatively narrow channels of laboratories imply high blockage ratios, which could affect the results, making them unreliable if extrapolated to full-scale cases. The main aim of this numerical study was to analyze the effects of the blockage caused by the laboratory channel walls in cases of current and also current surface waves. For this purpose, the performance predictions achieved for two turbines arranged in line for different lateral offsets in case of a typical laboratory scale were compared to the predictions obtained for a full scale, unconfined environment. The methodology consisted in the adoption a hybrid Blade Element Momentum–Computational Fluid Dynamics (BEM-CFD) approach, which was based on the Virtual Blade Model of ANSYS-Fluent. The results indicate that (1) the performance of a downstream turbine can increase up to 5% when this has a lateral separation of 1.5D from an upstream device in a full-scale environment compared to a misleading 15% calculated for the laboratory set-up, and (2) the relative fluctuations of power and thrust generated by waves are not significantly affected by the domain dimensions.


2015 ◽  
Vol 48 (26) ◽  
pp. 236-241 ◽  
Author(s):  
Fabrício G. Nogueira ◽  
Walter Barra ◽  
Carlos T. da Costa ◽  
José A.L. Barreiros ◽  
Jânio José de Lana

Author(s):  
Wendimu Melese

The current study was conducted at Jimma University College of Agriculture and Veterinary Medicine of Ethiopia to find the effect of farm yard manure application rate on yield and yield component of lettuce. The experiment was arranged at three levels of farm yard manure (5 ton/ha, 10 ton/ha and 15 ton/ha).  Each treatment was arranged as 1.1 kg, 2.25 kg and 3.3 kg/1.5 m2as T2, T3 and T4 respectively, and the control (0 kg/1.5 m2) as T1. A total of four treatments have been used. As the experimental tests showed that, farm yard manure with the rate of 3.3kg (15 ton/hek) is highly increased the yield and yield components of lettuce (plant height, leaf size, number of leaf per plant, fresh leaf weight, root depth and number of root per plant. Hence, it is recommended for general cultivation of lettuce under Jimma growing condition. Moreover, as the crop is growing at small scale farmer’s level in Jimma area further studies are needed with regard to the improvement of agronomic practices for lettuce at commercial level cultivation in Jimma and similar agro ecology.


2010 ◽  
Vol 1 (1) ◽  
pp. 182-189
Author(s):  
Jeroen Van Wittenberghe ◽  
Jan De Pauw ◽  
Patrick De Baets ◽  
Wim De Waele ◽  
Wouter Ost ◽  
...  

Threaded pipe connections are used to connect well casing, well tubing, drill pipes and risers.For many of these applications fatigue resistance plays an important role. In this study the fatigueproperties of threaded connections are studied using a combination of finite element modelling andexperimental testing. Using 2D axisymmetric FE analysis several connections are compared. It is shownthat the load distribution over the engaged threads is an important feature. Experimental tests are carriedout on three setups. A small scale four-point bending setup is used to develop S-N curves. An S-N curve fora standard API Line Pipe connection is compared to an S-N curve for a connection that showed animproved load distribution over the engaged threads in the FE analysis. On a medium scale four-pointbending setup, strains together with crack opening are measured. The strain measurements are comparedwith the strains obtained by the numerical model. Finally a full scale resonant bending fatigue setup ispresented, which will be used in future testing of pipe connections ranging from 168 mm (6”) to 508 mm(20”) in diameter.


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