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A noise source identification technique for the analysis of thermal systems is presented. The proposed method uses transient spectral sound data to assist in determining the source of sound radiation by tracking the variation of the frequency of tones during transient thermal loading (i.e., thermal system warm-up). By considering the temperature dependence of the modulus of elasticity (Young's modulus) it can be shown that structure related tones will decrease in frequency during warm-up. Tones due to propagation of sound in many fluids (i.e., gases and water) will increase in frequency during warm-up due to the temperature dependence of the speed of sound. The analysis method is demonstrated by identifying the source of several noise tones for a pulse combustion furnace.

The feasibility of controlling the threshing cylinder of a conventional corn combine with electro hydraulic elements controlled by a digital computer was concluded. The laboratory experiments attained the performance index established after consultation with manufacturers and farmers

The relationship of slip resistance (or coefficient of friction) to safe climbing system maneuvers on high profile vehicles has become an issue because of its possible connection to falls of drivers. To partially address this issue, coefficients of friction were measured for seven of the more popular fabricated metal step materials. Evaluated on these steps were four types of shoe materials (crepe, leather, ribbed-rubber, and oil-resistant-rubber) and three types of contaminant conditions (dry, wet-water, and diesel fuel). The final factor evaluated was the direction of sole force application. Results showed that COF varied primarily as a function of sole material and the presence of contaminants. Unexpectedly, few effects were attributible to the metal step materials. Numerous statistical interactions suggested that adequate levels of COF are more likely to be attained by targeting control on shoe soles and contaminants rather than the choice of a particular step material.

Grazing flows over open windows or sunroofs may result in “flow buffeting,” i.e. self-sustained flow oscillations at the Helmholtz acoustic resonance frequency of the vehicle. The associated pressure fluctuations may cause passenger fatigue and discomfort. Many solutions have been proposed to solve this problem, including for example leading edge spoilers, trailing edge deflectors, and leading edge flow diffusers. Most of these control devices are “passive” i.e. they do not involve dynamic control systems. Active control methods, which do require dynamic controls, have been implemented with success for different cases of flow instabilities. Previous investigations of the control of flow-excited cavity resonance have used mainly one or more loudspeakers located within the cavity wall. In this study, oscillated spoilers hinged near the leading edge of the cavity orifice were used. Experiments were performed using a cavity installed within the test section wall of a wind tunnel.

Original equipment manufacturers and their customers are demanding more efficient, lighter, smaller, safer, and smarter systems across the entire product line. In the realm of automotive, agricultural, construction, and earth-moving equipment industries, an additional highly desired feature that has been steadily trending is the capability to offer remote and autonomous operation. With the previous requirements in mind, the authors have proposed and validated a new electrohydraulic steering technology that offers energy efficiency improvement, increased productivity, enhanced safety, and adaptability to operating conditions. In this paper, the authors investigate the new steering technology's capacity to support remote operation and demonstrate it on a compact wheel loader, which can be remotely controlled without an operator present behind the steering wheel. This result establishes the new steer-by-wire technology's capability to enable full autonomous operation as well.