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This study analyzes the necessity, development, and principles of aero-engine electrostatic monitoring technology. An electrostatic sensor with specific size is assembled in the exhaust nozzle of an RB-211 turbofan engine located near the low-pressure turbine outlet, a stress checking procedure for safety is conducted. Two test program cycles are included in the whole experimental process. Electrostatic signal processing flow is presented, and feature parameters used for analysis are root-mean-square (RMS), activity level (AL), negative event rate (NER), positive event rate (PER), kurtosis, impulse factor, and absolute mean value. Thrust is used to parameterize the working conditions of the turbofan engine. Moreover, data fitting is conducted to determine the relations between feature and performance parameters. Accordingly, lubrication oil leakage fault and fuel-rich combustion condition are detected in two test run cycles, which result in the appearance of abnormal signals. The AL, RMS, and absolute mean values exhibit similar trends with the change in thrust. A positive linear correlation is also observed between the AL and the thrust in the varying thrust test period. The method of blade-casing rubbing fault recognition is discussed. Experiment results show that the electrostatic sensor is very sensitive to large-sized charged particles in the exhaust emissions.

This study proposes a novel curved steel plate damper to improve the seismic performance of structures. The theoretical analysis of the curved plate damper was carried out deriving formulas of key parameters of the curved plate damper including elastic lateral stiffness, yield strength, and yield displacement. Moreover, a cyclic loading test of four sets of specimens was conducted, and the hysteretic performance, ductility, energy dissipation performance, and strain of the specimens were studied. The results showed that the initial stiffness of the damper was large, no obvious damage was observed, and the hysteresis loop was full. The tested dampers had good deformation and energy dissipation performance. The stress variable rule of the damper was obtained by stress analysis, where the plastic deformation at the end of the semi-circular arc was large. The formula for various parameters of the damper was compared with experimental and numerical results, thus, the value of the adjustment coefficient was determined reasonable. Meanwhile, the rationality of the finite element model was also verified.

This paper measures the performance parameter of the automobile braking system with Electronic Vacuum Booster (EVB) through real vehicle experiment. According to the data collected from the experiment, the performance parameters of EVBs in different cars are not the same. The performance parameters of the EVB in both test cars can be separated into three parts. For example, when the desired braking intension, in other words the input signal of electronic vacuum booster, is less than 7, the braking effect is not obvious; when the desired braking intension is between 7~40, the relationship between the desired braking intension and the acceleration is found to be linear variation; when the desired braking intension is greater than 40, the wheels will be locked and the acceleration is constant. Then the authors get the performance parameter of automobile braking system with electronic vacuum booster through linear regression. The results can be used for automatic brake control.

A new constitutive formulation, the so-called Performance Dependent Model valid for normal and high strength concretes is presented. The distinctive aspect of the proposed model is the consideration of relevant properties of concrete mix components in the evaluation of the involved material performance or quality at the macroscopic stand point. In this way, the composite features of concrete are appropriately taken into account.The model maximum strength surface is defined by means of the Performance Dependent Failure Criterion proposed by the authors in previous works. Concrete behaviors in pre and post peak regimes are modeled with a non uniform hardening law and an isotropic softening rule, respectively. To realistically reproduce the concrete ductility in pre and post peak regimes under different load scenarios, the hardening and softening laws are dened in terms of the acting conning pressure. Concrete dilatancy behavior is approached by means of a volumetric non associative fow rule. The softening law is embedded in fracture energy concepts for mode I and II types of failure. The model considers two main input material parameters: the uniaxial compressive strength and the performance parameter, a quality index defined in the context of the Performance Dependent Failure Criterion.The proposed constitutive model is able to capture the substantial differences in the failure behavior of normal and high strength concretes as well as of concretes with the same compressive strength but different mix components. The predictive capabilities of the model are demonstrated in the numerical analyses included in this paper where the numerical predictions are compared with experimental results related to concrete specimens of different qualities and subjected to stress histories under both compressive and tensile regimes. Fil: Folino, Paula. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina Fil: Etse, Jose Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Centro de Métodos Numéricos y Computacionales en Ingeniería; Argentina

The advantages of desiccant-based air conditioning systems, compared to conventional ones based on the dehumidification by cooling, have been highlighted in many research papers. The energy saving and the reduction of the environmental impact are higher when the desiccant material is regenerated by using “free” thermal energy (for example, waste heat from cogenerators or solar energy). Further investigation on the performance of the desiccant wheel is useful: therefore, in this paper, an experimental analysis on this component is presented, with particular attention to the variation of the performance as a function of the process and regeneration air flow rates. The desiccant material is regenerated by means of low-temperature thermal energy (about 65 °C) from a microcogenerator. Both the experimental results obtained by the authors and the data provided by the manufacturer have been used to calculate some performance parameters, and a satisfactory agreement has been obtained. The performance parameters have been evaluated as a function of the regeneration temperature, the inlet process air humidity ratio and temperature and the ratio between the regeneration and process air flow rates, in both the cases of fixed regeneration temperature and fixed regeneration thermal power: the results show that higher influence on the dehumidification process is due to the regeneration temperature rather than to the regeneration air flow rate. Moreover, the process air humidity ratio and regeneration temperature influence the desiccant wheel performance more than the process air temperature.