Browse Topic: Roll
Jet Propulsion Laboratory Pasadena, CA
Water removal from Proton Exchange Membrane (PEM) Fuel Cell (FC) mainly involves two phenomena: some of the emerging droplets will roll on the Gas Diffusion Layer (GDL), others may impact channel walls and start sliding along the airflow direction. This different behaviour is linked to the hydrophobic/hydrophilic nature of the surface the water is moving on. In this paper, the walls of the channel of a FC were characterized by applying optical techniques. The deposition of droplets on the channel wall led to an evaluation of the proper range for Contact Angle Hysteresis (CAH = 55° - 45°), and due to the high wettability of the surface, droplets dimension was defined with a dimensionless parameter B/H. Under high crossflow condition (15 m/s) a sliding behaviour was observed. The channel features determined through image processing were used as boundary conditions for a 2D CFD two phase simulation employing the Volume of Fluid (VOF) model to keep track of the fluids interface. A droplet
Potholes are a major cause of discomfort for riders and vehicle damage. The passive suspension systems which are used in the passenger vehicles are primarily reaction based. These can’t adapt to the changing road conditions which means the best ride quality and handling characteristics cannot be ensured for different driving situations. Passive suspension system also needs more maintenance due to its inability to reduce the impact of the road irregularities. In recent years, semi-active suspension systems have been developed to improve ride comfort and vehicle safety. This paper covers the integration of a semi-active suspension system with a road preview mechanism with a TATA car model to investigate its impact on ride comfort, handling characteristics and component loads in digital domain. A quarter car vehicle model is used to compare different active damping control strategies. The best strategy is selected and integrated in a full vehicle MBS model to gain deeper insight on ride
Fast, secure, and reliable systems are crucial in industries where time is money and efficiency is highly valued. One American steel mill experienced frequent downtime because of steel split retention rings falling off during operations, often resulting in chocks falling into the mill during roll changes. The process of reattaching the retention rings was slow and required multiple sets of hands to ensure a more secure fit.
Existing integral flow-through balances have been limited to five-component force and moment measurements (normal and side force; pitch, yaw, and rolling moment) excluding a sixth desired force measurement: axial force. To enable key aerospace R&D applications, NASA’s Langley Research Center has developed a single-piece flow-through transducer design capable of measuring all six components adding in the Axial force measurement.
Air pollution is a major public health problem. The World Health Organization has estimated that it leads to over four million premature deaths worldwide annually. Still, it is not always extensively measured. But now an MIT research team is rolling out an open-source version of a low-cost, mobile pollution detector that could enable people to track air quality more widely.
This SAE Aerospace Information Report (AIR) includes all missile and launch vehicle actuation systems, including electrohydraulic, electropneumatic, and electromechanical types. The data for many systems are not complete. As more information becomes available, periodic updates will be issued to complete existing data sheets and to add new ones. An index by type of vehicle and by type of actuation system is included. The actual data sheets in the body of the report are organized in alphabetical order.
This SAE Recommended Practice describes the test procedures for conducting quasi-static modular body strength tests for ambulance applications. Its purpose is to establish recommended test practices which standardize the procedure for Type I and Type III bodies, provide ambulance builders and end-users with testing procedures and, where appropriate, provide acceptance criteria that, to a great extent, ensures the ambulance structure meets the same performance criteria across the industry. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
This document describes a method to calculate noise level adjustments at locations behind an airplane (described by an angular offset or directivity) at the start of takeoff roll (SOTR). This method is derived from empirical data from jet aircraft (circa 2004), most of which are configured with wing-mounted engines with high by-pass ratios (Lau, et al., 2012). Methods are also described which apply to modern turboprop aricraft. Calculations of other propagation-related adjustments required for aircraft noise prediction models are described in AIR1845A, ARP5534, ARP866A, and AIR5662.
This specification covers aramid fibers in the form of woven cloth.
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