6,029 research outputs found
CONCENTRATION ISSUES IN THE U.S. BEEF SUBSECTOR
Industrial Organization, Livestock Production/Industries,
Investigating the impact of varying the number of distributed energy resources on controlling the power flow within a microgrid
The electrification of heat and transport in addition to integration of intermittent renewable resources into the existing electricity network is expected to occur in near future. Such a transformation is expected to force the operation of the electricity power system at different levels to its limits and would require reinforcement of the network assets at different levels. The incorporation of active management and control within microgrids and across the low voltage distribution network is thought as a cost effective solution which would facilitate wide scale integration of the emerging distributed energy resources. However since increasing the microgrid size at a certain DER penetration level would increase the total dispatchable power it is expected to affect the effectiveness of any control algorithm that operates at that level. This paper presents the findings obtained from of an investigation into the relationship between microgrid size and the effectiveness of a deterministic control algorithm implemented at that level
Power flow control for power and voltage management in future smart energy communities
The Community Power Flow Control (CPFC) Algorithm has been proposed as a technique for managing electrical power and energy within small communities. The CPFC manages the resources in the community (DSM, energy storage, RES) in order to control the community’s instantaneous power flow according to a target set by a higher-level management system. This paper investigates the capability of the CPFC to manage local distribution voltage levels. The power flow data for a community has been used together with transformer and cable impedance models to demonstrate the variation of the distribution voltage in a community with significant penetration of PV and EV. The CPFC is shown to manage the voltage levels along a feeder within the statutory limits, even when there is significant export
A novel stochastic modelling approach for electric vehicle charging power and energy requirements
Electrification of heat and transport in addition to integration of intermittent renewable resources into the existing electricity network is expected to occur in near future. Such a transformation is expected to force the operation of the electricity power system at different levels to its limits. A novel bottom up modelling approach for quantifying temporal variation of electric vehicle charging power and energy is presented in this paper which can be used to accurately investigate the effect of charging different penetration levels of electric vehicles within the low voltage distribution network. This EV charging model is further used for development of a deterministic control algorithm for regulating power flows at the low voltage level
Status of Solar Sail Propulsion: Moving Toward an Interstellar Probe
NASA's In-Space Propulsion Technology Program has developed the first-generation of solar sail propulsion systems sufficient to accomplish inner solar system science and exploration missions. These first-generation solar sails, when operational, will range in size from 40 meters to well over 100 meters in diameter and have an areal density of less than 13 grams-per-square meter. A rigorous, multiyear technology development effort culminated last year in the testing of two different 20-meter solar sail systems under thermal vacuum conditions. This effort provided a number of significant insights into the optimal design and expected performance of solar sails as well as an understanding of the methods and costs of building and using them. In a separate effort, solar sail orbital analysis tools for mission design were developed and tested. Laboratory simulations of the effects of long-term space radiation exposure were also conducted on two candidate solar sail materials. Detailed radiation and charging environments were defined for mission trajectories outside the protection of the earth's magnetosphere, in the solar wind environment. These were used in other analytical tools to prove the adequacy of sail design features for accommodating the harsh space environment. Preceding, and in conjunction with these technology efforts, NASA sponsored several mission application studies for solar sails, including one that would use an evolved sail capability to support humanity's first mission into nearby interstellar space. The proposed mission is called the Interstellar Probe. The Interstellar Probe might be accomplished in several ways. A 200-meter sail, with an areal density approaching 1 gram-per-square meter, could accelerate a robotic probe to the very edge of the solar system in just under 20 years from launch. A sail using the technology just demonstrated could make the same mission, but take significantly longer. Conventional chemical propulsion systems would require even longer flight times. Spinner sails of the type being explored by the Japanese may also be a good option, but the level of maturity in that technology is not clear. While the technology to support a 200-meter, ultralightweight sail mission is not yet in hand, the recent NASA investments in solar sail technology are an essential first step toward making it a reality. This paper will describe the status of solar sail propulsion within NASA, near-term solar sail mission applications, and the plan to advance the technology to the point where the Interstellar Probe mission can be flown
Palliative care and Parkinson's disease : meeting summary and recommendations for clinical research
Introduction: Palliative care is an approach to caring for patients and families affected by serious illnesses that focuses on the relief of suffering through the management of medical symptoms, psychosocial issues, advance care planning and spiritual wellbeing. Over the past decade there has been an emerging clinical and research interest in the application of palliative care approaches to Parkinson’s disease (PD) and outpatient palliative care services are now offered by several movement disorders centers. Methods: An International Working Group Meeting on PD and Palliative Care supported by the Parkinson’s Disease Foundation was held in October 2015 to review the current state of the evidence and to make recommendations for clinical research and practice. Results: Topics included: 1) Defining palliative care for PD; 2) Lessons from palliative care for heart failure and other chronic illnesses; 3) Patient and caregiver Needs; 4) Needs assessment tools; 5) Intervention strategies; 6) Predicting prognosis and hospice referrals; 7) Choice of appropriate outcome measures; 8) Implementation, dissemination and education research; and 9) Need for research collaborations. We provide an overview of these discussions, summarize current evidence and practices, highlight gaps in our knowledge and make recommendations for future research. Conclusions: Palliative Care for PD is a rapidly growing area which holds great promise for improving outcomes for PD patients and their caregivers. While clinical research in this area can build from lessons learned in other diseases, there is a need for observational, methodological and interventional research to address the unique needs of PD patients and caregivers
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