13 research outputs found
Low-Power and Programmable Analog Circuitry for Wireless Sensors
Embedding networks of secure, wirelessly-connected sensors and actuators will help us to conscientiously manage our local and extended environments. One major challenge for this vision is to create networks of wireless sensor devices that provide maximal knowledge of their environment while using only the energy that is available within that environment. In this work, it is argued that the energy constraints in wireless sensor design are best addressed by incorporating analog signal processors. The low power-consumption of an analog signal processor allows persistent monitoring of multiple sensors while the device\u27s analog-to-digital converter, microcontroller, and transceiver are all in sleep mode. This dissertation describes the development of analog signal processing integrated circuits for wireless sensor networks. Specific technology problems that are addressed include reconfigurable processing architectures for low-power sensing applications, as well as the development of reprogrammable biasing for analog circuits
Low-Power and Programmable Analog Circuitry for Wireless Sensors
Embedding networks of secure, wirelessly-connected sensors and actuators will help us to conscientiously manage our local and extended environments. One major challenge for this vision is to create networks of wireless sensor devices that provide maximal knowledge of their environment while using only the energy that is available within that environment. In this work, it is argued that the energy constraints in wireless sensor design are best addressed by incorporating analog signal processors. The low power-consumption of an analog signal processor allows persistent monitoring of multiple sensors while the device\u27s analog-to-digital converter, microcontroller, and transceiver are all in sleep mode. This dissertation describes the development of analog signal processing integrated circuits for wireless sensor networks. Specific technology problems that are addressed include reconfigurable processing architectures for low-power sensing applications, as well as the development of reprogrammable biasing for analog circuits
Electronics for Sensors
The aim of this Special Issue is to explore new advanced solutions in electronic systems and interfaces to be employed in sensors, describing best practices, implementations, and applications. The selected papers in particular concern photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) interfaces and applications, techniques for monitoring radiation levels, electronics for biomedical applications, design and applications of time-to-digital converters, interfaces for image sensors, and general-purpose theory and topologies for electronic interfaces
Solar Energy: Applications, Economics and Public Perception
This book discusses the applications, economics,
and public perceptions of solar energy conversion systems. The
book is divided into fi ve sections: the fi rst section provides an overview of
hybrid solar energy systems, the second discusses solar energy and conservation
issues, the third focuses on solar energy technology, the fourth
section is on the economics of solar energy, and, fi nally, the fi nal section
addresses public perceptions of solar energy.
In Chapter 1, Chow and colleagues give a broad review of the published
academic works on hybrid photovoltaic/thermal (PVT) collector
systems, with an emphasis placed on the research and development activities
in the last decade.
In Chapter 2, Cameronand colleagues examine the synergy between
renewable energy generation goals and those for biodiversity conservation
in the Mojave Desert of the southwestern USA. They integrate spatial
data on biodiversity conservation value, solar energy potential, and land
surface slope angle (a key determinant of development feasibility) and
found there to be suffi cient area to meet renewable energy goals without
developing on lands of relatively high conservation value. Indeed, they
found nearly 200,000 ha of lower conservation value land below the most restrictive slope angle (<1%); that area could meet the state of California’s
current 33% renewable energy goal 1.8 times over. They found over
740,000 ha below the highest slope angle (<5%)—an area that can meet
California’s renewable energy goal seven times over. Their analysis also
suggests that the supply of high quality habitat on private land may be
insuffi cient to mitigate impacts from future solar projects, so enhancing
public land management may need to be considered among the options
to offset such impacts. Using the approach presented here, planners could
reduce development impacts on areas of higher conservation value, and
so reduce trade-offs between converting to a green energy economy and
conserving biodiversity.
Klinger and colleagues presents proof-of-concept all-carbon solar
cells in Chapter 3. These solar cells are made of a photoactive side of predominantly
semiconducting nanotubes for photo-conversion and a counter
electrode made of a natural mixture of carbon nanotubes or graphite, connected
by a liquid electrolyte through a redox reaction. The cells do not
require rare source materials such as In or Pt, nor high-grade semiconductor
processing equipment. They do not rely on dye for photo-conversion
and therefore do not bleach, and are easy to fabricate using a spray-paint
technique. They observed that cells with a lower concentration of carbon
nanotubes on the active semiconducting electrode perform better than
cells with a higher concentration of nanotubes. This effect is contrary to
the expectation that a larger number of nanotubes would lead to more photo-
conversion and therefore more power generation. The authors attribute
this to the presence of metallic nanotubes that provide short for photo-excited
electrons, bypassing the load. They demonstrate optimization strategies
that improve cell effi ciency by orders of magnitude and conclude that,
once it is possible to make semiconducting-only carbon nanotube fi lms
that may provide the greatest effi ciency improvement.
In Chapter 4, Denholm and Mehos examines the degree to which concentrating
solar power (CSP) may be complementary to PV via its use of thermal energy storage. The authors fi rst review the challenges of PV
deployment at scale with a focus on the supply/demand coincidence and
limits of grid fl exibility. They then perform a series of grid simulations to
indicate the general potential of CSP with thermal energy storage (TES)
to enable greater use of solar generation, including additional PV
2009 Annual Progress Report: DOE Hydrogen Program
This report summarizes the hydrogen and fuel cell R&D activities and accomplishments of the DOE Hydrogen Program for FY2009. It covers the program areas of hydrogen production and delivery; fuel cells; manufacturing; technology validation; safety, codes and standards; education; and systems analysis