Matching Items (5)
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- All Subjects: Acoustics
- Creators: Phelan, Patrick
- Creators: Daliri, Ayoub
Description
In these times of increasing industrialization, there arises a need for effective and energy efficient heat transfer/heat exchange devices. The focus nowadays is on identifying various methods and techniques which can aid the process of developing energy efficient devices. One of the most common heat transfer devices is a heat exchanger. Heat exchangers are an essential commodity to any industry and their efficiency can play an important role in making industries energy efficient and reduce the energy losses in the devices, in turn decreasing energy inputs to run the industry.
One of the ways in which we can improve the efficiency of heat exchangers is by applying ultrasonic energy to a heat exchanger. This research explores the possibility of introducing the external input of ultrasonic energy to increase the efficiency of the heat exchanger. This increase in efficiency can be estimated by calculating the parameters important for the characterization of a heat exchanger, which are effectiveness (ε) and overall heat transfer coefficient (U). These parameters are calculated for both the non-ultrasound and ultrasound conditions in the heat exchanger.
This a preliminary study of ultrasound and its effect on a conventional shell-and-coil heat exchanger. From the data obtained it can be inferred that the increase in effectiveness and overall heat transfer coefficient upon the application of ultrasound is 1% and 6.22% respectively.
One of the ways in which we can improve the efficiency of heat exchangers is by applying ultrasonic energy to a heat exchanger. This research explores the possibility of introducing the external input of ultrasonic energy to increase the efficiency of the heat exchanger. This increase in efficiency can be estimated by calculating the parameters important for the characterization of a heat exchanger, which are effectiveness (ε) and overall heat transfer coefficient (U). These parameters are calculated for both the non-ultrasound and ultrasound conditions in the heat exchanger.
This a preliminary study of ultrasound and its effect on a conventional shell-and-coil heat exchanger. From the data obtained it can be inferred that the increase in effectiveness and overall heat transfer coefficient upon the application of ultrasound is 1% and 6.22% respectively.
ContributorsAnnam, Roshan Sameer (Author) / Phelan, Patrick (Thesis advisor) / Rykaczewski, Konrad (Committee member) / Milcarek, Ryan (Committee member) / Arizona State University (Publisher)
Created2019
Description
Spatial awareness (i.e., the sense of the space that we are in) involves the integration of auditory, visual, vestibular, and proprioceptive sensory information of environmental events. Hearing impairment has negative effects on spatial awareness and can result in deficits in communication and the overall aesthetic experience of life, especially in noisy or reverberant environments. This deficit occurs as hearing impairment reduces the signal strength needed for auditory spatial processing and changes how auditory information is combined with other sensory inputs (e.g., vision). The influence of multisensory processing on spatial awareness in listeners with normal, and impaired hearing is not assessed in clinical evaluations, and patients’ everyday sensory experiences are currently not directly measurable. This dissertation investigated the role of vision in auditory localization in listeners with normal, and impaired hearing in a naturalistic stimulus setting, using natural gaze orienting responses. Experiments examined two behavioral outcomes—response accuracy and response time—based on eye movement in response to simultaneously presented auditory and visual stimuli. The first set of experiments examined the effects of stimulus spatial saliency on response accuracy and response time and the extent of visual dominance in both metrics in auditory localization. The results indicate that vision can significantly influence both the speed and accuracy of auditory localization, especially when auditory stimuli are more ambiguous. The influence of vision is shown for both normal hearing- and hearing-impaired listeners. The second set of experiments examined the effect of frontal visual stimulation on localizing an auditory target presented from in front of or behind a listener. The results show domain-specific effects of visual capture on both response time and response accuracy. These results support previous findings that auditory-visual interactions are not limited by the spatial rule of proximity. These results further suggest the strong influence of vision on both the processing and the decision-making stages of sound source localization for both listeners with normal, and impaired hearing.
ContributorsClayton, Colton (Author) / Zhou, Yi (Thesis advisor) / Azuma, Tamiko (Committee member) / Daliri, Ayoub (Committee member) / Arizona State University (Publisher)
Created2021
Description
Prosodic features such as fundamental frequency (F0), intensity, and duration convey important information of speech intonation (i.e., is it a statement or a question?). Because cochlear implants (CIs) do not adequately encode pitch-related F0 cues, pre-lignually deaf pediatric CI users have poorer speech intonation perception and production than normal-hearing (NH) children. In contrast, post-lingually deaf adult CI users have developed speech production skills via normal hearing before deafness and implantation. Further, combined electric hearing (via CI) and acoustic hearing (via hearing aid, HA) may improve CI users’ perception of pitch cues in speech intonation. Therefore, this study tested (1) whether post-lingually deaf adult CI users have similar speech intonation production to NH adults and (2) whether their speech intonation production improves with auditory feedback via CI+HA (i.e., bimodal hearing). Eight post-lingually deaf adult bimodal CI users and nine NH adults participated in this study. 10 question-and-answer dialogues with an experimenter were used to elicit 10 pairs of syntactically matched questions and statements from each participant. Bimodal CI users were tested under four hearing conditions: no-device (ND), HA, CI, and CI+HA. F0 change, intensity change, and duration ratio between the last two syllables of each utterance were analyzed to evaluate the quality of speech intonation production. The results showed no significant differences between CI and NH participants in any of the acoustic features of questions and statements. For CI participants, the CI+HA condition led to significantly greater F0 decreases of statements than the ND condition, while the ND condition led to significantly greater duration ratios of questions and statements. These results suggest that bimodal CI users change the use of prosodic cues for speech intonation production in different hearing conditions and access to auditory feedback via CI+HA may improve their voice pitch control to produce more salient statement intonation contours.
ContributorsAi, Chang (Author) / Luo, Xin (Thesis advisor) / Daliri, Ayoub (Committee member) / Davidson, Lisa (Committee member) / Arizona State University (Publisher)
Created2022
Description
Desorption processes are an important part of all processes which involve utilization of solid adsorbents such as adsorption cooling, sorption thermal energy storage, and drying and dehumidification processes and are inherently energy-intensive. Here, how those energy requirements can be reduced through the application of ultrasound for three widely used adsorbents namely zeolite 13X, activated alumina and silica gel is investigated. To determine and justify the effectiveness of incorporating ultrasound from an energy-savings point of view, an approach of constant overall input power of 20 and 25 W was adopted. To measure the extent of the effectiveness of using ultrasound, the ultrasonic-power-to-total power ratios of 0.2, 0.25, 0.4 and 0.5 were investigated and the results compared with those of no-ultrasound (heat only) at the same total power. Duplicate experiments were performed at three nominal frequencies of 28, 40 and 80 kHz to observe the influence of frequency on regeneration dynamics. Regarding moisture removal, application of ultrasound results in higher desorption rate compared to a non-ultrasound process. A nonlinear inverse proportionality was observed between the effectiveness of ultrasound and the frequency at which it is applied. Based on the variation of desorption dynamics with ultrasonic power and frequency, three mechanisms of reduced adsorbate adsorption potential, increased adsorbate surface energy and enhanced mass diffusion are proposed. Two analytical models that describe the desorption process were developed based on the experimental data from which novel efficiency metrics were proposed, which can be employed to justify incorporating ultrasound in regeneration and drying processes.
ContributorsDaghooghi Mobarakeh, Hooman (Author) / Phelan, Patrick (Thesis advisor) / Wang, Liping (Committee member) / Wang, Robert (Committee member) / Calhoun, Ronald (Committee member) / Deng, Shuguang (Committee member) / Arizona State University (Publisher)
Created2021
Description
The phase change process of freezing water is an important application in several fields such as ice making, food freezing technologies, pharmaceuticals etc. Due to the widespread usage of ice-related products, process improvements in this technology can potentially lead to substantial energy savings. After studying the freezing process of water, the supercooling phenomenon was found to occur which showed a negative effect. Therefore, ultrasound was proposed as a technique to reduce the supercooling effect and improve the heat transfer rate. An experimental study was conducted to analyze the energy expenditures in the freezing process with and without the application of ultrasound. After a set of preliminary experiments, an intermittent application of ultrasound at 10W & 3.5W power levels were found to be more effective than constant-power application, and were explored in further detail. The supercooling phenomenon was thoroughly studied through iterative experiments. It was also found that the application of ultrasound during the freezing process led to the formation of shard-like ice crystals. From the intermittent ultrasound experiments performed at 10W and 3.5W power levels, percentage energy enhancements relative to no ultrasound of 8.9% ± 12.4% and 11.9% ± 24.6% were observed, respectively.
ContributorsSubramanian, Varun (Author) / Phelan, Patrick (Thesis advisor) / Calhoun, Ronald (Committee member) / Rykaczewski, Konrad (Committee member) / Arizona State University (Publisher)
Created2021