Helicopter Inside Cabin Acoustic Evaluation: A Case Study—IAR PUMA 330

This paper presents an inside-cabin acoustic evaluation of the IAR PUMA 330 helicopter, manufactured by IAR S.A. Brasov. In this study, based on the acoustic assessment inside the helicopter, areas with high noise levels are identified. In this regard, several tests were carried out in accordance with the ISO 5129 standard. In the first stage of the assessment, a measurement campaign was performed to identify the acoustic leaks from the outside noise sources propagating inside the cabin (in the door area) and the acoustic attenuation of the helicopter structure. These tests were performed on the factory runway, with the helicopter in parked position (ground tests). During the ground tests, the helicopter engines were turned off. The tests consisted of placing two loudspeakers directed towards the helicopter door and generating pink noise. Inside the helicopter, the entire door frame opening was scanned with an intensity probe to identify acoustic leaks areas. The second assessment stage was to determine the areas of the cabin with the highest levels of noise. Within the measurement campaign, 16 microphones were placed inside the cabin, at the level of the passengers’ heads, arranged in seven zones. The tests were carried out with the helicopter engines started, staying at fixed point above the ground (hovering), and then a flight test, in which all the maneuvers necessary for the use of the helicopter were performed (in-flight tests). Based on the measurement results, it was possible to highlight the noise spectral components in each of the seven areas. The noise assessment revealed high noise levels inside the cabin, having as main noise sources the transmission gear and the door area, leading to the need for reducing the noise exposure for passengers and crew, thus the need to reduce noise levels inside the helicopter.

Analyzing mechanical vibrations of an aircraft opposed piston engine

The paper presents the results of the bench tests to measure mechanical vibrations of a new aircraft opposed piston engine with reciprocating pistons. The PLZ-100 engine is a three-cylinder, six-piston, two-shaft drive unit with a two-stroke diesel cycle. This type of engine is dedicated for powering light aircraft, e.g. autogyros. The tests were carried out on a test bench at the Lublin University of Technology. The engine was loaded with constant torque, for several fixed values of rotational speed of a crankshaft. The angle of the start of diesel injection was changed for each of the rotational speeds. The mechanical vibrations that accompanied the operation of this drive unit were recorded with three measurement transducers and a National Instruments conditioning system. Each of the transducers was mounted on a different axis of the engine. The signals were analyzed from their courses with the DIAdem software. The results were the courses of effective speed and vibration acceleration to conduct a vibration-acoustic evaluation of the PLZ-100, detect and prevent various types of defects or failures.

Acoustic Evaluation of Annulus B Barriers Through Tubing for Plug and Abandonment Job Planning

The need to evaluate cement behind multiple casing strings has become critical in the context of well plug and abandonment (P&A) or slot recovery. A particularly important case, addressed in this work, is the application to optimize P&A operations in offshore wells where the capability to evaluate barriers behind casing using tools deployed inside an inner tubing would reduce the costs associated with rig time and potentially (in case the presence of barriers outside the casing is confirmed) the unnecessary removal of casing strings. We present an approach using a combination of sonic and ultrasonic tools deployed inside tubing to characterize the near well bore environment and in particular, the annular fill and bond behind the outer casing, i.e. in annulus B. Extensive modeling and experiments were used to characterize the sonic response in a dual string geometry and identify features that inform on the state of annulus B. Some of the complexities and ambiguities in this complex scenario are addressed by using the ultrasonic tool to characterize the annulus behind the tubing (annulus A) as well as the tubing location inside the casing. Additionally, we combine the single feature answers with those using deep machine learning to learn the complex relationship of the subtle features in the through tubing sonic response to the finer variations of the annulus B state as indicated by ultrasonic cement maps acquired in the outer casing. We test and validate these answers on a number of field jobs and show the results of the through-tubing logging answers with the reference cement evaluation maps obtained after removing the tubing.

A Multisensory Deficit in the Perception of Pleasantness in Parkinson’s Disease

Background: There is growing interest in non-motor symptoms in Parkinson’s disease (PD), due to the impact on quality of life. Anhedonia, the inability to experience joy and lust, has a prevalence of up to 46% in PD. The perception of pleasantness of an odor is reduced in anhedonia without PD. We previously showed a reduced hedonic olfactory perception in PD, i.e., patients evaluated odors as less pleasant or unpleasant compared to controls. This deficit correlated with anhedonia. Objective: We aimed to confirm these findings. Moreover, we hypothesized that the perception of pleasantness in PD is affected on a multisensory level and correlates with anhedonia. Therefore, we assessed olfactory, visual and acoustic evaluation of pleasantness in PD and healthy individuals. Methods: Participants had to rate the pleasantness of 22 odors, pictures, and sounds on a nine-point Likert scale. Depression, anhedonia, and apathy were assessed by means of questionnaires. Results of the pleasantness-rating were compared between groups and correlated to scores of the questionnaires. Results: In particular pleasant and unpleasant stimuli across all three modalities are perceived less intense in PD, suggesting that a reduced range of perception of pleasantness is a multisensory phenomenon. However, only a reduction of visual hedonic perception correlated with anhedonia in PD. A correlation of reduced perception of pleasantness with apathy or depression was not present. Conclusion: We provide evidence for a multisensory deficit in the perception of pleasantness. Further studies should delineate the underlying neural circuity and the diagnostic value to detect neuropsychiatric symptoms in PD.