Automated acoustic intensity measurements and the effect of gear tooth profile on noise

Acoustic intensity measurements were made at NASA Lewis Research Center on a spur gear test apparatus. The measurements were obtained with the Robotic Acoustic Intensity Measurement System developed by Cleveland State University. This system provided dense spatial positioning, and was calibrated against a high quality acoustic intensity system. The measured gear noise compared gearsets having two different tooth profiles. The tests evaluated the sound field of the different gears for two speeds and three loads. The experimental results showed that gear tooth profile had a major effect on measured noise. Load and speed were found to have an effect on noise also

Comparison of analysis and experiment for gearbox noise

Low contact ratio spur gears were tested in the NASA gear-noise rig to study the noise radiated from the top of the gearbox. Experimental results were compared with a NASA acoustics code to validate the code for predicting transmission noise. The analytical code is based on the boundary element method (BEM) which models the gearbox top as a plate in an infinite baffle. Narrow band vibration spectra measured at 63 nodes on the gearbox top were used to produce input data for the BEM model. The BEM code predicted the total sound power based on the measured vibration. The measured sound power was obtained from an acoustic intensity scan taken near the surface of the gearbox at the same 63 nodes used for vibration measurement. Analytical and experimental results were compared at four different speeds for sound power at each of the narrow band frequencies over the range of 400 to 3200 Hz. Results are also compared for the sound power level at meshing frequency plus three sideband pairs and at selected gearbox resonant frequencies. The difference between predicted and measure sound power is typically less than 3 dB with the predicted value generally less than the measured value

Effect of operating conditions on gearbox noise

Low contact ratio spur gears were tested in the NASA gear noise rig to study the noise radiated from the top of the gearbox. The measured sound power from the gearbox top was obtained from a near field acoustic intensity scan taken at 63 nodes just above the surface. The sound power was measured at a matrix of 45 operating speeds and torque levels. Results are presented in the form of a spectral speed map and as a plot of sound power versus torque (at constant speed) and as sound power versus speed (at constant torque). Because of the presence of vibration modes, operating speed was found to have more impact on noise generation than torque level. A NASA gear dynamics code was used to compute the gear tooth dynamic overload at the same 45 operating conditions used for the experiment. Similar trends were found between the analytical results for dynamic tooth overload and experimental results for sound power. Dynamic analysis may be used to design high quality gears with profile relief optimized for minimum dynamic load and noise

Stresses and Strains Distribution of a Developed Cold Bituminous Emulsion Mixture Using Finite Element Analysis

Cold bitumen emulsion mixtures (CBEMs) offer an energy-efficient, sustainable and cost-effective alternative to conventional hot asphalt mixtures, as no heating is required to produce the CBEMs. The enhancement of flexible pavements performance by modifying asphalt mixture has been considered valuable. This is due to the undesirable environmental conditions and heavy loads that will cause unsatisfactory performance of conventional mixtures. Empirical methods using layers with elastic response have been largely used to design such mixtures. Currently fast and powerful design techniques are used to reduce the limitation in determining stresses, strains and displacement in flexible pavements analysis. This research presents a simple and more practicable design procedure of CBEM and discusses limitations of this design. Also, present the properties and characteristics of modified CBEMs for surface course mixture using glass fibre as a reinforcing material. In addition, a three-dimensional (3D) finite element analysis (FEA) simulation for the prediction of pavement mechanical behaviour and performance is carried out using ABAQUS software in which element types, model dimensions and meshing have been taken to achieve appropriate accuracy and convergence

Automated Acoustic Intensity Measurements and the Effect of Gear Tooth Profile on Noise

Acoustic intensity measurements were made at NASA Lewis Research Center on a spur gear test apparatus. The measurements were obtained with the Robotic Acoustic Intensity Measurement System developed by Cleveland State University. This system provided dense spatial positioning, and was calibrated against a high quality acoustic intensity system. The measured gear noise compared gearsets having two different tooth profiles. The tests evaluated the sound field of the different gears for two speeds and three loads. The experimental results showed that gear tooth profile had a major effect on measured noise. Load and speed were found to have an effect on noise also

The Impact of a Vocational Counseling Based Substance Abuse Intensive Outpatient Program upon Work and Well-Being: A Pilot Study

Even though recovery from Substance Use Disorders (SUDs) involves changes among a number of life domains, services have traditionally focused on abstinence from substances. Cursory attention is placed on holistic treatment approaches for persons with SUDs, such as vocational counseling services to address employment related concerns. In response to this need, the purpose of this study was to explore the influence of an innovative treatment approach for individuals with SUDs. Specifically, an exploration of the impact of an innovative intervention that prepares consumers in SUD treatment for gainful employment for the purpose of improving work and well-being outcomes was conducted.  Participants were consumers who received services from a Substance Abuse Intensive Outpatient Program at East Carolina University and consented to participate (N = 69). Based on Life-Course theory and previous literature on the interplay of employment and the treatment of SUDs, the following research questions and hypotheses were generated. Research question 1 explored the impact of consumer demographic factors on SAIOP participation. Research question 2 explored the impact of SAIOP participation on work and well-being outcomes, and was tested through the following five hypotheses: (1) The longer the SAIOP participation, the more likely the participants were to be employed full- or part-time; (2 - 5) As participants' SAIOP participation increased, the severity of their employment issue, alcohol use, drug use, and psychiatric issue problem severity would decrease. For research question 1, results revealed one significant association, where consumers with no high school education had more participation hours in job readiness training than those with a high school degree or GED. For research question 2, the results revealed support for hypothesis 1, that longer hours of participation was associated with an increased likelihood of employment, and hypothesis 4, that longer hours of participation was associated with a decrease in drug use problem severity. The results did not show support for hypotheses 2, 3, or 5.   The results demonstrate the interplay between work and treatment for SUDs. Further, this study shows support re-conceptualizing SUDs treatment delivery to include a more life-course, holistic approach. Thus, this study has implications for rehabilitation counselors and administrators.  Ph.D

Effect of Operating Conditions on Gearbox Noise

Low-contact-ratio spur gears were tested in the NASA gear noise rig to study the noise radiated from the top of the gearbox. The measured sound power from the gearbox top was obtained from a near-field acoustic intensity scan taken at 63 nodes just above the surface. The sound power was measured at a matrix of 45 operating speeds and torque levels. Results are presented in the form of a spectral speed map and as plots of sound power versus torque (at constant speed) and as sound power versus speed (at constant torque) Because of the presence of vibration modes, operating speed was found to have more impact on noise generation than torque level. A NASA gear dynamics code was used to compute the gear tooth dynamic overload at the same 45 operating conditions used for the experiment. Similar trends were found between the analytical results for dynamic tooth overload and experimental results for sound power. Dynamic analysis may be used to design high-quality gears with profile relief optimized for minimum dynamic load and noise

Health Inequalities in the British Nursing Workforce

Background Average health in the UK is improving, yet geographical inequalities in health persist. The relative difference between the least and most deprived is also growing. Recent policy interventions to reduce these inequalities have not been effective. Methods This work compares Self-Rated Health using the ONS LS and SLS linked to an adjusted UK-consistent small-area Deprivation measure. This study aims to compare Nurses to the general population to assess whether they also exhibit a social gradient in health. Using a single occupational group adjusts for potential confounders and tests whether characteristics of Nurses, such a good health literacy, degree education and above average income, are protective against inequalities. Results In Scotland, Nurses are more likely to be older, female, homeowners who live in less deprived areas with better Self-Rated Health than Non-Nurses. We will test whether the social gradient in health is observed for this occupational group. Forthcoming results from cross-national analysis will be presented at conference following disclosure checks. Conclusion The relationship between area deprivation and health may remain even in relatively privileged groups. Results from this study may inform recommendations to improve the effectiveness of policy aimed at improving population health and reducing socio-economic inequalities in healt

Development of a new SonovueTM contrast-enhanced ultrasound approach reveals temporal and age-related features of muscle microvascular responses to feeding

Compromised limb blood flow in aging may contribute to the development of sarcopenia, frailty, and the metabolic syndrome. We developed a novel contrast-enhanced ultrasound technique using Sonovue™ to characterize muscle microvasculature responses to an oral feeding stimulus (15 g essential amino acids) in young (~20 years) and older (~70 years) men. Intensity-time replenishment curves were made via an ultrasound probe “fixed” over the quadriceps, with intermittent high mechanical index destruction of microbubbles within muscle vasculature. This permitted real-time measures of microvascular blood volume (MBV), microvascular flow velocity (MFV) and their product, microvascular blood flow (MBF). Leg blood flow (LBF) was measured by Doppler and insulin by enzyme-linked immunosorbent assay. Steady-state contrast concentrations needed for comparison between different physiological states were achieved <150 sec from commencing Sonovue™ infusion, and MFV and MBV measurements were completed <120 sec thereafter. Interindividual coefficients of variation in MBV and MFV were 35–40%, (N = 36). Younger men (N = 6) exhibited biphasic vascular responses to feeding with early increases in MBV (+36%, P < 0.008 45 min post feed) reflecting capillary recruitment, and late increases in MFV (+77%, P < 0.008) and MBF (+130%, P < 0.007 195 min post feed) reflecting more proximal vessel dilatation. Early MBV responses were synchronized with peak insulin but not increased LBF, while later changes in MFV and MBF occurred with insulin at post absorptive values but alongside increased LBF. All circulatory responses were absent in old men (N = 7). Thus, impaired postprandial circulation could impact age-related declines in muscle glucose disposal, protein anabolism, and muscle mass