Low-frequency Acoustic Noise Mitigation Characteristics of Metamaterials-inspired Vibro-impact Structures

Acoustic absorbers like foams, fiberglass or liners have been used commonly in structures for infrastructural, industrial, automotive and aerospace applications to mitigate noise. However, these conventional materials have limited effectiveness to mitigate low-frequency (LF) acoustic waves with frequency less than $\sim$400 Hz owing to the need for impractically large mass or volume. LF acoustic waves contribute significantly towards environmental noise pollution as well as unwanted structural responses. Therefore, there is a need to develop lightweight, compact, structurally-integrated solutions to mitigate LF noise in several applications. Inspired by metamaterials, which are manmade structural materials that derive their unique dynamic behavior not just from material constituents but more so from engineered configurations, tuned mass-loaded membranes as vibro-impact attachments on a baseline structure are investigated to determine their performance as a LF acoustic barrier. The hypothesis is that the LF incident waves are up-converted via impact to higher modes in the baseline structure which are far more evanescent and may then be effectively mitigated using conventional means. Such Metamaterials-Inspired Vibro-Impact Structures (MIVIS) could be tuned to match the dominant frequency content of LF acoustic sources in specific applications. Prototype MIVIS unit cells were designed and tested to study the energy transfer mechanism via impact-induced frequency up-conversion, and the consequent sound transmission loss. Structural acoustic simulations were done to predict responses using models based on normal incidence transmission loss tests. Experimental proof-of-concept was achieved and further correlations to simulations were utilized to optimize the energy up-conversion mechanism using parametric studies. Up to 36 dB of sound transmission loss increase is obtained at the anti-resonance frequency (326 Hz) within a tunable LF bandwidth of about 200 Hz while impact-induced up-conversion could enable further broadband transmission loss via subsequent dissipation in conventional absorbers. Moreover, this approach while minimizing parasitic mass addition retains or could conceivably augment primary functionalities of the baseline structure. Successful transition to applications could enable new mission capabilities for aerospace and military vehicles and help create quieter built environments.Mechanical & Aerospace Engineerin

Risk management in Indian Banking Sector

A research topic detailing the various risk management techniques in place for the Indian Banking Sector

The effects of liking norms and descriptive norms on vegetable consumption:a randomised experiment

There is evidence that social norm messages can be used to promote the selection of fruit and vegetables in low habitual consumers of these foods but it is unclear whether this effect is sustained over time. It is also unclear whether information about others' liking for a food (liking norm) could have the same effect. Using a 2 × 5 × 2 experimental design we investigated the effects of exposure to various messages on later intake from a food buffet and whether any effects were sustained 24 h after exposure in both low and high consumers of vegetables. There were three factors: delay (immediate food selection vs. food selection 24 h after exposure), message type (liking norm, descriptive norm, health message, vegetable variety condition, and neutral control message), and habitual consumption (low vs. high). The buffet consisted of three raw vegetables, three energy-dense foods, and two dips. For vegetables and non-vegetables there were no main effects of message type, nor any main effect of delay. There was a significant message × habitual vegetable consumption interaction for vegetable consumption; however, follow up tests did not yield any significant effects. Examining each food individually, there were no main effects of message type, nor any main effect of delay, for any of the foods; however, there was a message × habitual vegetable consumption interaction for broccoli. Consumption of broccoli in the health message and descriptive norm conditions did not differ from the control neutral condition. However, habitually low consumers of vegetables increased their consumption of broccoli in the vegetable variety and liking norm conditions relative to habitual low vegetable consumers in the neutral control condition (p < 0.05). Further, investigation of the effects of the liking norm and vegetable variety condition on vegetable intake is warranted. This trial is listed as NCT02618174 at clinicaltrials.gov

Investigation of Interventions for Increasing Consumption of Fruit and Vegetables in Australia for Better Health

This thesis investigates novel strategies for increasing consumption of fruit and vegetables for better health. The literature review analysed the effectiveness of global social marketing campaigns promoting consumption of fruit and vegetables. The research experiments focused on studying interventions for increasing vegetable consumption in Australia. The first experiment was a national online survey designed to evaluate the Veggycation website and its appeal to particular demographic groups of consumers. The second experiment investigated top-of-mind health benefits consumers perceive about specific vegetables, to guide the use of nutrition and health claims on vegetable marketing collateral. The third experiment was an online survey of NSW respondents to examine the impact of a celebrity cooking show video-clip on consumer intentions and behaviour regarding vegetable consumption. Overall, the findings of this research highlight that consumer demographics have a significant influence on fruit and vegetable consumption. Children are a good target group for campaigns promoting fruit and vegetable uptake as they show the greatest change in consumption and carry their healthy eating habits into adulthood. Women demonstrate greater knowledge and attitudes towards vegetable intake. They also exhibit higher cooking confidence towards vegetables and are generally the primary shopper influencing family consumption. The understanding of specific vegetable related health benefits is low among the Australian population. Customisation of promotional interventions would assist in bringing a positive change in vegetable intake. The Australian vegetable industry would benefit from promoting the Veggycationwebsite in conjunction with public health organisations. Linking public health experts with TV celebrity chefs would also assist in reinforcing the message. This thesis makes a substantial contribution to the existing body of knowledge in the study of vegetable consumption

Risk management in Indian Banking Sector

A research topic detailing the various risk management techniques in place for the Indian Banking Sector

Consumer evaluation of ‘Veggycation®’ : a website promoting the health benefits of vegetables

Issue addressed: Whether the website Veggycation® appeals to particular groups of consumers significantly more than other groups. Methods: Australian adults aged _18 years (n = 1000) completed an online survey. The website evaluation instrument used was tested for validity and reliability. Associations between demographic variables and website evaluation dimensions of attractiveness, content, user-friendliness and loyalty intentions were examined using a general linear model (GLM). The appraisal of the website was further investigated based on the respondents’ daily consumption level of vegetables and the importance they attach to vegetable consumption in their diet, using GLM and a Tukey’s all-pair comparison. Results: Veggycation® has a high level of acceptance among the Australian community with certain groups evaluating the website more favourably. These include women, people aged_29 years, higher income respondents, non-metro respondents and those who viewed vegetables as extremely important in their daily diet. Conclusions: Customisation of the website for consumer groups with low vegetable consumption is recommended. Designing tailored communication tools will assist in enhancing the knowledge base of vegetable-related health benefits and may promote vegetable consumption among the Australian population

Australian consumer awareness of health benefits associated with vegetable consumption

Aim: The present study investigated the perceived health benefits of specific vegetable consumption to guide the use of nutrition and health claims on vegetable marketing collateral. Methods: Free elicitation and consumer ranking data were collected through an online survey of 1000 adults from across Australia and analysed for the perceived importance of vegetables in the daily diet, number of serves consumed per day, knowledge about health-related benefits of specific vegetables and perceived health benefits of vegetable consumption. Results: The importance of vegetables in the diet and daily vegetable consumption was higher in people from an English-speaking background, females, people aged 45years and over and people living in non-metropolitan areas. Digestion was selected as the major health benefit from consumption of specific vegetables. However, understanding of the health benefits of specific vegetable consumption was relatively low among consumers. Half of the respondents were not sure of the health benefits associated with specific vegetables, except for carrots and spinach. Some respondents volunteered nutrient content or other information. Conclusions: There was no clear indication that consumers understand the specific health benefits conferred by consumption of vegetables. Nutrient and health benefit labelling therefore has the capacity to enhance knowledge of vegetable consumers. It is recommended that health benefit labelling be tailored to promote greater consumption of vegetables in those demographic groups where vegetable consumption was lower. The present study assists the Australian vegetable industry in helping consumers make more informed consumption choices