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This article presents an innovative application of the frequency domain decomposition method based on an acoustic and vibration response. Frequency domain decomposition method has been frequently used for operational modal analysis testing in the last decade to identify modal parameters for in-situ case studies. For these studies, the outputs of the vibration response through accelerometers have been employed in the analysis. In this article, the frequency domain decomposition method is employed, for the first time, to analyze both acoustic and vibration response of the building which is a novel application in building vibration response. As a case study, a cylindrical shaped seven-story building, which appears to be subjected to a vibration problem, was selected. In this research, both acoustic and vibration responses are captured to determine the source of this unknown excitation. The results show that using microphones, as an acoustic response, can be as reliable as accelerometers to identify forced vibration.

As rotary machines have become more complicated, balancing processes have been classified as a vital step in condition monitoring to ensure that machines operate reliably, smoothly and safely. All rotating objects will deflect during rotation and all objects possess certain natural frequencies in the absence of rotation. However, an unbalanced object can cause significant unwanted deflection created by resonant vibration at a frequency (cycles/second) close to certain rotational speeds (rotations/second), known as critical speeds. This is especially important for flexible machines which normally work at rotations above their critical speeds. Imbalance is a common problem in flexible rotating machinery that can lead to extreme vibration and noise levels. This is one of the major reasons for studying various balancing methods applied to the vibration response of rotating machines. Recently, the relation between acoustic and vibration response during a rotary machine balancing process based on the original Four-Run method has been presented for constant speed machines. This method cannot be applied to machines in start-up or shut-off. Hence, by considering the acoustic and vibration responses of a machine between its critical speeds, this research presents a new innovative speed-variant balancing method based on the original Four-Run method, named as (PPCS) Peak to Peak for Critical Speeds. The proposed method consists of two major types of application: the first is in the run-up of the machine and the second is in shut down. Experimental laboratory results show that this method can be implemented for speed-variant and flexible rotary machines during run-up or shut-down transient processes based on acoustic and vibration measurements. Further, the results show the same trend in acoustic and vibration responses during balancing process which was shown for constant speed rotary machines. With a 40% improvement in response compared to around 55% obtained by traditional vibration measurements, the results found show an appreciable benefit in an alternative acoustic methodology that may have not been considered previously for run-up and shut-down issues. In addition, since only the magnitude of response is required and this is a non-contact technique an acoustic-only methodology, it can be employed with some confidence as an innovative and readily available method for condition monitoring.

The rapid development of industry results in large energy consumption and a negative impact on the environment. Pollution of the environment caused by conventional energy sources such as petrol leads to increased demand for propulsion systems with higher efficiency and capable of energy-saving and emission reduction. The usage of hybrid technology is expected to improve energy conversion efficiency, reduce energy consumption and environmental pollution. In this paper, the simulation platform for the hybrid unmanned aerial vehicle (UAV) has been built by establishing the subsystem models of the UAV power system. Under the two chosen working conditions, the conventional cruise flight mission and the terrain tracking mission, the power tracking control and Q-Learning method have been used to design the energy management controller for the hybrid UAV. The fuel consumption and pollutant emissions under each working condition were calculated. The results show that the hybrid system can improve the efficiency of the UAV system, reduce the fuel consumption of the UAV, and so reduce the emissions of CO2, NOx, and other pollutants. This contributes to improving of environmental quality, energy-saving, and emission reduction, thereby contributing to the sustainable development of aviation.

Balancing a rotating machine is a vital step towards ensuring it will operate reliably and safely. To achieve this condition monitoring is an important aspect for early faulty detection and it can also result in the improvement of the operational continuity and equipment safety. Imbalance itself, is a common problem in rotating machinery and it can lead to poor or even dangerous vibration levels. And, for example, it is also well known that misalignment can lead to bearing defects. So, in order to overcome these problems many balancing techniques have been developed that are largely based on measured vibration data using accelerometers attached to the faulty device. The three-point method is well known as a basic phase-less technique; this method has been used for balancing equipment and is widely regarded as an industry standard technique. In this work we avoid placing sensors on the device under investigation. This is achieved by utilizing a microphone method located in the nearfield of the investigated device. By comparing the traditional vibration technique with the acoustic contact-less method we can demonstrate the method’s remarkable accuracy. Finally, the experimental results show that there is a similar trend between both the vibration and acoustical responses of the machine, and it is proven that it is possible to balance a rotating machine by just utilizing the acoustical response. This is a contactless method and an innovation in machine-dynamics condition monitoring.

In transition from concept design to detail design, designers and engineers need to find specific materials to optimize performance of the systems. The large number of materials and the wide range of manufacturing processes cause engineers always to seek new materials selection methods. In this research work a new method so called QFD method, which employs materials indices, is introduced. The method enjoys a combination of Ashby’s materials selection concepts with the Quality Function Deployment (QFD) tool. The QFD method, which is modified here to fit the materials selection field, provides the designer with the required weighting factors for the material indices. Incorporation of House of Quality makes it possible to add the effects of the interrelationship of the material indices to the calculation of the required weighting factors. Also, considering the material indices would preserve the generality and quality of the results. The results show that the method can provide comparable outputs to the existing methods. Also, the results prove that considering materials selection methods like MDL and Z-transformation which employ material properties instead of material indices would not adversely affect the results. Though, some differences could be noticed and also the QFD is capable of analyzing much more complicated problems.