Search Results

Foaming of a thermoplastic polyolefin (TPO) is gaining interests because of its superior mechanical properties of foamed automotive parts, such as lightweight and high performance to weight ratio, etc. In this context, understanding of the thermophysical properties of PP/gas and TPO/gas mixtures is critically important. This paper will present the newly developed experimental technique to accurately measure the swelling of PP and TPO due to gas dissolution at elevated temperatures and pressures. Our technique measures the geometry of the pendent drop accurately from the captured images to obtain the volume swelling data. It determines the boundary location of the polymer/gas sample accurately by magnifying the sample drop locally along its edge before capturing the image. The automated high-precision XY stage is chosen as the platform to control the motion of the CCD camera.

This paper describes the design and development of a virtual environment conceived to support flight operations of an Unmanned Air Vehicle (UAV) used for wind mapping in the proximity of existing or planned wind farms. The virtual environment can be used in pre-flight briefings aiming to define a trajectory from a list of waypoints, to change and eventually re-plan the mission in case of intersection with no fly zones, to simulate the mission, and to preview images/videos taken from the UAV on-board cameras. During flight, the tool can be used to compute the wind speed along the trajectory by analyzing the data streaming from the UAV. The integration of Augmented Reality (AR) techniques in the flight environment provides assistance in remotely piloted landings, and allows visualizing flight and environmental information that are critical to the mission.

Quasicrystalline (QC) coatings were evaluated as leading-edge protection materials for rotor craft blades. The QC coatings were deposited using high velocity oxy-fuel thermal spray and predominantly Al-based compositions. Ice adhesion, interfacial toughness with ice, wettability, topography, and durability were assessed. QC-coated sand-blasted carbon steel exhibited better performance in terms of low surface roughness (Sa ~ 0.2 μm), liquid repellency (water contact angles: θadv ~85°, θrec ~23°), and better substrate adhesion compared to stainless steel substrates. To enhance coating performance, QC-coated sand-blasted carbon steel was further exposed to grinding and polishing, followed by measuring surface roughness, wettability, and ice adhesion strength. This reduced the surface roughness of the QC coating by 75%, resulting in lower ice adhesion strengths similar to previously reported values (~400 kPa).

The Enhanced/Synthetic Vision System (E/SVS) is a Technology Demonstrator (TD) project supported by the Chief, Research and Development of the Canadian Department of National Defence. E/SVS displays an augmented visual scene to the pilot that includes three separate image sources: a synthetic computer - generated terrain image; an enhanced visual image from an electro-optical sensor (fused as an inset); and aircraft instrument symbology, all displayed to the pilot on a Helmet Mounted Display (HMD). The synthetic component of the system provides a 40 degree vertical by 80 degree horizontal image of terrain and local features. The enhanced component digitizes imagery from electro-optic sensors and fuses the sensor image as an inset (20 degrees by 25 degrees) within the synthetic image. Symbology can be overlaid in any location within the synthetic field-of-view and may be head, aircraft, target or terrain referenced.

Polymers are often blended to create compounds with new or enhanced properties in order to compensate for an individual polymer's weakness or lack of inherent properties. In the field of polymer foaming, polymer blends are also used to generate fine-cell structures via heterogeneous nucleation. Recently, an interest in physical blowing agents, such CO2 and N2, has increased because of their low impact on the environment. It has thus become additionally important to pursue research on the foaming of polymer blends employing these particular physical blowing agents in an effort to keep up with the demand for environmentally friendly products. In this study, thermoplastic polyolefin (TPO) blends were prepared with polypropylene (PP) and a metallocene-based polyolefin elastomer (POE) using twin-screw extruders and a batch mixer.

Metallic open-cell foams have proven to be valuable for many engineering applications. Their success is mainly related to mechanical strength, low density, high specific surface, good thermal exchange, low flow resistance and sound absorption properties. The present work aims to investigate three principal aspects of real foams: the geometrical characterization, the flow regime characterization, the effects of the pore size and the porosity on the pressure drop. The first aspect is very important, since the geometrical properties depend on other parameters, such as porosity, cell/pore size and specific surface. A statistical evaluation of the cell size of a foam sample is necessary to define both its geometrical characteristics and the flow pattern at a given input velocity. To this purpose, a procedure which statistically computes the number of cells and pores with a given size has been implemented in order to obtain the diameter distribution.

The maturity reached in the development of Unmanned Air Vehicles (UAVs) systems is making them more and more attractive for a vast number of civil missions. Clearly, the introduction of UAVs in the civil airspace requiring practical and effective regulation is one of the most critical issues being currently discussed. As several civil air authorities report in their regulations “Sense and Avoid” or “Detect and Avoid” capabilities are critical to the successful integration of UAV into the civil airspace. One possible approach to achieve this capability, specifically for operations beyond the Line-of-Sight, would be to equip air vehicles with a vision-based system using cameras to monitor the surrounding air space and to classify other air vehicles flying in close proximity. This paper presents an image-based application for the supervised classification of air vehicles.

Shock absorbers and damper systems are important parts of automobiles and motorcycles because they have effects on safety, ride comfort, and handling. In particular, for vehicle safety, shock absorber system plays a fundamental role in maintaining the contact between tire and road. Generally, to assure the best trade-off between safety and ride comfort, a fine experimental tuning on all shock absorber components is necessary. Inside a common damper system the presence of several conjugated actions made by springs, oil and pressurized air requires a significant experimental support and a great number of prototypes and test. Aimed to reduce the design and tuning phases of a damper system, it is necessary to join these phases together with a numerical modelling phase. The aim of this paper is to present the development of a mono-dimensional (1D) model for simulating dynamic behaviour of damper system.