experimental

摘要： This work presents the study of a throttling water jet through the opening 2.45 mm in diameter, with a speed of 21.2 meters per second hitting a pressure point distance of 30 mm in a dead impact wall. The impact turns instantly the throttling water jet into the circular flow, which is rotating in a vortical manner around the mixing chamber longitudinal axis with a speed of rotation of 122 revolutions per second (The miniature injector LK26M, Figure 4 Charts 5, Figure 5). With sufficient large air intake openings, the increase of the vortex flow speed, the suction pressure of the circular, vortex flow forestall the static pressure increase in the filling in the chamber circular flow, that is directed to the air intake openings, as a result, water running out of air intake openings is impossible and only air is being sucked in the mixing chamber, the circular flow is accelerated and in a fraction of a second stabilized.

摘要： In this paper, the performance and overall efficiency optimization process for a full-electric Formula Student car are reported. The Formula Student Electric is a scientific-educational competition of high technological value that requires the development and construction of a fully electric open-wheel prototype car;the cars rival both in terms of absolute performance and in terms of total energy efficiency, especially in the most important test, the endurance event. The optimization of the performance and efficiency of the cars affects various aspects of both the powertrain and the car body and, as macro areas, three crucial themes can be identified for the development of the cars: the power maps with which the inverter manages the electric motor, the aerodynamic kit installed onboard and the overall weight of the car. In this regard, in fact, it is not obvious, for example, that it is convenient to use the maximum power allowed by the rules for the powertrain (80 kW);in the same way, it is not inevitable that it is advantageous to install all the components of the aerodynamic kit (front wing, rear wing and undertray with diffusers) and, finally, the best configuration may not be the one with the lightest car. This is also in consideration of the fact that some choices must necessarily be a compromise, such as completeness of the aerodynamic kit and vehicle weight. Hence the search for an optimum point is necessary. The work proposed here aims to describe the experimental search for the optimal configuration for the car of the Sapienza Fast Charge team. To achieve the goal, the analysis has been conducted with several experimental tests on a simple test ring with a dynamic configuration comparable to that of a typical endurance track. The tests have been fulfilled with different combinations of aero-kit configurations, with the aero devices available on the car, rear wing, front wing and undertray, and with different energy management strategies, implemented in the power map of the inverter. The best result has been achieved considering the official ranking calculation of the Formula Student rules 2020, with a combination of best track time and lower energy consumption. The work described here will start with the description of the prototype vehicle, reporting the details of the powertrain and storage system installed onboard. Then, the aerodynamic devices designed and built will be described, and the CFD analysis of their performances will also be reported. In the following, the description of the test track will be discussed and a comparison of a typical track of an Endurance test in Formula Student will be fulfilled. Finally, the parameters measured experimentally will be described and all the tests carried out will be discussed, in order to determine the optimal configuration of the car.

摘要： The electrical energy produced must be consumed at the same time, hence the need to achieve a balance between supply and demand. Therefore, the production, transport, and distribution systems together constitute an electricity network. The distribution networks are designed to deliver energy to consumers. Unacceptable voltage drops are observed in the distribution networks of developing countries such as Burkina Faso. A study was carried out on the distribution network of the city of Bobo-Dioulasso in Burkina Faso. It allowed for experimentation with the “Megger MPQ1000” network analyzer to evaluate the quality of the voltage supplied to households. To this end, tests were carried out in a public distribution station and at a few subscribers in the Sarfalao district of the city of Bobo-Dioulasso. These tests were used to assess the percentage of voltage drops. These values, which are higher than 8% of the nominal voltage, are not regulatory. The load curves of the consumers in the district were also drawn. Indeed, the period of the high load is between 19:00 and 23:00 Local Time (LT), while the period of the medium and low load is between 00:00 and 18:00 LT.

摘要： This study proposes a novel U-shaped 65Mn steel bumper as the displacement restraining device for base-isolated structures with laminated elastomeric rubber bearings.A series of bumpers with different geometric parameters were designed and tested under monotonic and cyclic quasi-static loading protocols.The experimental results from a total of 232 specimens were analyzed to develop an analytical model to calculate the backbone curve and the maximum elastic restoring force for U-shaped 65Mn bumpers.Thus,the analytical equations to calculate the elastic,hardening,and unloading stiffness of U-shaped 65Mn bumpers,as well as their maximum elastic restoring force,are validated by using an additional ten groups of bumpers with varying radiuses.These analytical equations can accurately predict the mechanical parameters of U-shaped 65Mn steel bumpers for a design purpose.

摘要： Different imines were prepared.The reaction was carried out using different conditions,with aromatic aldehydes,aniline and with different energy sources.Yield,purity and experimental fusion point were calculated in each case,and they were compared to the ones found in literature.The importance of structural effects of aldehyde reacting with aniline was established as well as reaction conditions.The efficacy of the reaction can not be predicted,since each aldehyde has a different structure and therefore reacts differently.The main objective of this project is academic.A methodology to carry out a structured research(it is one of the levels of problem-based learning(ABP)),was implemented.Students work in pairs using Combinatorial Chemistry,and each pair does a different exercise on the same theoretical objective.Results from every team are discussed in a seminary where conclusions regarding which was the most efficient reaction are reached.

摘要： The problem of the churning loss in swash plate axial piston machines is investigated through experimental measurement and theoretical analysis. Several works surrounding churning loss in hydraulic components have been proposed in the past, but few have conducted experimental studies and accounted for both dry and wet housing conditions. In this study,a specializedexperimental setup is established, which includes a transparent test pump diligently designed for performing various functions of tests. The test pump can work as a real pump without losing any actual features of pump operation. The torque loss in both the dry housing pump and wet housing pump is measured in terms of the shaft speed and its predictive model is also developed analytically. The comparisons between measured and calculated torque loss are presented, showing how speed influences torque loss in both conditions. The advantage/disadvantages of the two cases are summarized. The significance of the test setup is highlighted by verifying the proposed model, which can advance the understanding of energy losses of high speed pumps in future.

摘要： In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.

摘要： The purpose of this paper is to study the energy efficiency of a local living space exposed to solar radiation in the subtropical climate of Casablanca. The study was mainly focused on the contribution of a phase change material (PCM), inserted into a 7-cm thick air layer of a double brick wall, in two different locations. We note that the experimental study was conducted using two real-scale test cavities, located in the Faculty of Science Ain Chock-Casablanca. Two PCM mounting methods were used for the south and west walls, in order to test its energy efficiency as a storage and retrieval means of the solar flux coming from the outside. In the case of the southern wall, the PCM is put directly on the internal side of the outside part of the double wall (Case 1). For the west wall, the PCM is placed 1.2 cm away from the internal side of the outer part of the double wall (Case 2). The first result shows that the PCM placed to the wall allows storing the solar heat during the day and releasing it to the outside of the building at night. While in the second case, the PCM keeps the heat stored day and night.