INFLUENCE OF FEATURES OF THE ELECTRIC FIELD IN THE DIAPHRAGM SYSTEM ON THE TRANSPORTATION OF THE FLOW OF CHARGED PARTICLES AT ATMOSPHERIC PRESSURE

The results of numerical simulation of the ion-optical scheme of ion transport at atmospheric pressure are presented. The possibility of efficient transport of ions in the system under consideration with an increase in the local curvature of the equipotential lines of the electrostatic field in the vicinity of the nozzle by shaping (changing the shape) of this electrode is shown. Shaping the nozzle allows to increase the value of Iсопло by approximately 1.6 times. Taking into account the gas-dynamic effect on the transport of the ion beam through the nozzle makes it possible to obtain the values of the transmission by 70% higher.

Development and validation of the first brazilian french-based asphalt mix complex modulus and fatigue test apparatus

The main aim of this paper is to present the development and validation procedures of the first brazilian french-based asphalt mix complex modulus and fatigue test apparatus, so-called FADECOM, in order to demonstrate the effective application of the results obtained in pavement design procedures. Magnetic sensitive Hall Effect non-contact captors determine amplitude displacement, while loading cells capture force amplitude by a diaphragm system. Independent cooling and heating chambers assure a precise temperature control comprising a range from -30ºC to above 100ºC with an accuracy of 0.1ºC. A frequency inverter controls the emission of pulses usually set from 1Hz to 30Hz. For validating the apparatus, a scientific cooperation agreement was dealt with French Institute of Transportation Sciences and Technologies, Development and Road Network (IFSTTAR), in which specimen samples were tested in both UFSC and IFSTTAR laboratories. The crossed-results obtained indicate an excellent performance and accuracy of FADECOM apparatus, presenting variations around just 3 microstrains in determining fatigue strains at 106 cycles (e6) and less than 10% related to the complex stiffness modulus, demonstrating huge accuracy of the FADECOM apparatus and its practical feasibility to be applied in pavement design procedures, based on the technical principles of French methodology.

Design of a Prototype for the In Situ Forming of a Liquid-Infused Preform Process

The world is changing and demanding stronger, lighter, and more versatile materials. Taking advantage of the full potential of these materials also requires versatile manufacturing processes. The in situ forming of a liquid-infused preform (ISFLIP) is a new manufacturing process for fiber-reinforced polymer (FRP) parts with shell shapes. ISFLIP is a hybrid process between vacuum infusion (VI) and diaphragm forming. This paper focuses on the mechanical design and experimental validation of a functional prototype of ISFLIP. The novelty of the design lies especially in a double-diaphragm system that is fundamental to carrying out the forming just after the infusion stage. The double-diaphragm system and other two major subsystems, a vacuum table and an infrared heating grid, were devised to benefit from the operational advantages of ISFLIP. The whole prototype, once constructed, was tested by forming some demonstration components. The result of one of these components, a “C” cross-section FRP profile with two sharp joggles, is finally obtained, proving the feasibility of the prototype.

Vibration-induced drop atomization and bursting

A liquid drop placed on a vibrating diaphragm will burst into a fine spray of smaller secondary droplets if it is driven at the proper frequency and amplitude. The process begins when capillary waves appear on the free surface of the drop and then grow in amplitude and complexity as the acceleration amplitude of the diaphragm is slowly increased from zero. When the acceleration of the diaphragm rises above a well-defined critical value, small secondary droplets begin to be ejected from the free-surface wave crests. Then, quite suddenly, the entire volume of the drop is ejected from the vibrating diaphragm in the form of a spray. This event is the result of an interaction between the fluid dynamical process of droplet ejection and the vibrational dynamics of the diaphragm. During droplet ejection, the effective mass of the drop–diaphragm system decreases and the resonance frequency of the system increases. If the initial forcing frequency is above the resonance frequency of the system, droplet ejection causes the system to move closer to resonance, which in turn causes more vigorous vibration and faster droplet ejection. This ultimately leads to drop bursting. In this paper, the basic phenomenon of vibration-induced drop atomization and drop bursting will be introduced, demonstrated, and characterized. Experimental results and a simple mathematical model of the process will be presented and used to explain the basic physics of the system.