24,947 research outputs found
Voltage regulator for battery power source
A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage
Zener-regulated solar array/battery power system
Zener diode limits solar cell voltage used to charge battery. System improves life and reliability of solar cells
Battery power
Electric cars have always looked like the future, but around the world they are becoming an everyday reality. Can Hong Kong avoid getting stuck in the past or will the city be able to join the electric car revolution
Ultralight reactive metal foams produced as structural shapes in space: System design
This autonomous experiment for foaming metals in space involved: (1) payload support structure; (2) furnace and foaming apparatus; (3) electronic controls; (4) battery power; and (5) metallurgy. Emphasis was laid on a modular design which was easily modifiable and which offered maximum durability, safety, and failure tolerance
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Incorporating Digital Repeaters into the Soft Handover Standard in Digital Video Broadcasting Handheld
Digital Video Broadcasting for Handhelds (DVB-H) is a standard for broadcasting IP data services to portable devices. Handover in unidirectional broadcast networks is a novel issue introduced by this technology. This paper proposes and analyses the Repeater Aided Soft Handover (RA_handover) algorithm for a DVB-H receiver with MIMO antennas and presents the benefits of implementing RA_handover compared with a handover process without repeaters. For network planning and optimisation purposes simulation models are developed to analyse the RA_handover approach. It is shown that RA_handover could greatly improve the quality of service and consume much less front-end battery power than a handover method without repeaters. In addition, the cost introduced by the algorithm is briefly estimated. In conclusion, curves are given that show the relationship between quality of service and consumed battery power, which provide further support for including RA_handover in the DVB-H soft handover standard. The paper provides valuable outcomes for service providers and standard policy makers
The LiAl/FeS2 battery power source for the future
Advanced high power density rechargeable batteries are currently under development. These batteries have the potential of greatly increasing the power and energy densities available for space applications. Depending on whether the system is optimized for high power or high energy, values up to 150 Wh/kg and 2100 W/kg (including hardware) are projected. This is due to the fact that the system uses a high conductivity molten salt electrolyte. The electrolyte also serves as a separator layer with unlimited freeze thaw capabilities. Life of 1000 cycles and ten calendar years is projected. The electrochemistry consists of a lithium aluminum alloy negative electrode, iron disulfide positive electrode, and magnesium oxide powder immobilized molten salt electrolyte. Processed powders are cold compacted into circular discs which are assembled into bipolar cell hardware with peripheral ceramic salts. The culmination of the work will be a high energy battery of 40 kWh and a high power battery of 28 kWh
Marine propulsion using battery power
Abstract: The global demand to reduce CO2 emissions requires effort from the shipping industry which currently emits about 2% of anthropogenic global Greenhouse Gases (GHGs) and which is predicted to increase due to growth of world trade. Therefore, it is important to find new ways to reduce CO2 emissions from shipping using new operational strategies, improved ship designs and new technologies.
Battery technologies have been developing rapidly leading the road transport industry into a greener future with hybrid and electric vehicles but such a change is not so apparent in the shipping industry. This paper provides an overview of the state of the art battery technology and important future developments that may potentially exploit batteries in future shipâs power and propulsion systems.
Through case studies, the paper assesses the applicability of battery power to ships, more specifically small ones. Approximately 14,000 ships, 22% of the global commercial fleet are below 400 gross tonnes, most of which are small coastal ships, e.g. tugs and passenger ships/ferries. Existing battery-powered ship system configurations are summarised; battery developments are considered, impacts of battery application on ship performance are discussed in the paper supported by a case study
A Cooperative Emergency Navigation Framework using Mobile Cloud Computing
The use of wireless sensor networks (WSNs) for emergency navigation systems
suffer disadvantages such as limited computing capacity, restricted battery
power and high likelihood of malfunction due to the harsh physical environment.
By making use of the powerful sensing ability of smart phones, this paper
presents a cloud-enabled emergency navigation framework to guide evacuees in a
coordinated manner and improve the reliability and resilience in both
communication and localization. By using social potential fields (SPF),
evacuees form clusters during an evacuation process and are directed to
egresses with the aid of a Cognitive Packet Networks (CPN) based algorithm.
Rather than just rely on the conventional telecommunications infrastructures,
we suggest an Ad hoc Cognitive Packet Network (AHCPN) based protocol to prolong
the life time of smart phones, that adaptively searches optimal communication
routes between portable devices and the egress node that provides access to a
cloud server with respect to the remaining battery power of smart phones and
the time latency.Comment: This document contains 8 pages and 3 figures and has been accepted by
ISCIS 2014 (29th International Symposium on Computer and Information
Sciences
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