3 resultados para Ultrasound sensors

em Bucknell University Digital Commons - Pensilvania - USA


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Electric power grids throughout the world suffer from serious inefficiencies associated with under-utilization due to demand patterns, engineering design and load following approaches in use today. These grids consume much of the world’s energy and represent a large carbon footprint. From material utilization perspectives significant hardware is manufactured and installed for this infrastructure often to be used at less than 20-40% of its operational capacity for most of its lifetime. These inefficiencies lead engineers to require additional grid support and conventional generation capacity additions when renewable technologies (such as solar and wind) and electric vehicles are to be added to the utility demand/supply mix. Using actual data from the PJM [PJM 2009] the work shows that consumer load management, real time price signals, sensors and intelligent demand/supply control offer a compelling path forward to increase the efficient utilization and carbon footprint reduction of the world’s grids. Underutilization factors from many distribution companies indicate that distribution feeders are often operated at only 70-80% of their peak capacity for a few hours per year, and on average are loaded to less than 30-40% of their capability. By creating strong societal connections between consumers and energy providers technology can radically change this situation. Intelligent deployment of smart sensors, smart electric vehicles, consumer-based load management technology very high saturations of intermittent renewable energy supplies can be effectively controlled and dispatched to increase the levels of utilization of existing utility distribution, substation, transmission, and generation equipment. The strengthening of these technology, society and consumer relationships requires rapid dissemination of knowledge (real time prices, costs & benefit sharing, demand response requirements) in order to incentivize behaviors that can increase the effective use of technological equipment that represents one of the largest capital assets modern society has created.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A new 2-D hydrophone array for ultrasound therapy monitoring is presented, along with a novel algorithm for passive acoustic mapping using a sparse weighted aperture. The array is constructed using existing polyvinylidene fluoride (PVDF) ultrasound sensor technology, and is utilized for its broadband characteristics and its high receive sensitivity. For most 2-D arrays, high-resolution imagery is desired, which requires a large aperture at the cost of a large number of elements. The proposed array's geometry is sparse, with elements only on the boundary of the rectangular aperture. The missing information from the interior is filled in using linear imaging techniques. After receiving acoustic emissions during ultrasound therapy, this algorithm applies an apodization to the sparse aperture to limit side lobes and then reconstructs acoustic activity with high spatiotemporal resolution. Experiments show verification of the theoretical point spread function, and cavitation maps in agar phantoms correspond closely to predicted areas, showing the validity of the array and methodology.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Horizontal cuts between the septum and preoptic area (anterior roof deafferentation, or ARD) dramatically affect sexual behavior, and in ways that could explain a variety of differences across behavioral categories (precopulatory, copulatory), species, and the sexes. Yet little is known about how these effects develop. Such information would be useful generally and could be pivotal in clarifying the mechanism for ultrasonic vocalization in female hamsters. Ultrasounds serve these animals as precopulatory signals that can attract males and help initiate mating. Their rates can be increased by either ARD or lesions of the ventromedial hypothalamus (VMN). If these effects are independent, they would require a mechanism that includes multiple structures and pathways within the forebrain and hypothalamus. However, it currently is not clear if they are independent: VMN lesions could affect vocalization by causing incidental damage to the same fibers targeted by ARD. Fortunately, past studies of VMN lesions have described a response with a very distinctive time course. This raises the possibility of assessing the independence of the two lesion effects by describing just the development of the response to ARD. To accomplish this, female hamsters were observed for levels of ultrasound production and lordosis before and after control surgery or ARD. As expected, both behaviors were facilitated by these cuts. Further, these effects began to appear by two days after surgery and were fully developed by six days. These results extend previous descriptions of the ARD effect by describing its development and time course. In turn, the rapid responses to ARD suggest that these cuts trigger disinhibitory changes in pathways that differ from those affected by VMN lesions. 2013