12 research outputs found
Radioiodination via isotope exchange in pivalic acid
A variety of benzoic and aryl aliphatic mono and polyiodinated acids and esters (sterol, triglyceride) were radioiodinated in 55-99% radiochemical yield by isotope exchange with Na 125I in a melt of pivalic acid. In general, the reaction was complete in 1 h at 155[deg]C with little or no substrate decompostion. High specific activity studies afforded 125I-labeled iopanoic acid with a specific activity of over 700 Ci/mmol.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26445/1/0000533.pd
Novel Topology of Saturated-core Fault Current Limiter
Increasing levels of fault currents in utility grids are expected to result in mechanical and thermal overstresses of different power system components. To cope with these increased levels, expensive upgrades and replacements of currently employed Circuit Breakers might be required in the near future. Fault Current Limiters (FCLs) are expected to play an important role in the protection of future energy systems. They limit a fault current to a predetermined level and have no influence on the system during normal operation. A number of different FCL types have been proposed in literature. FCLs based on core-saturation effect have a number of crucial operation advantages over other FCL types: they have no fault reaction delay and no post-fault recovery delay; they have high reliability, low losses and can limit any number of consecutive faults. By introducing FCLs in power systems, above-mentioned expensive upgrades can be avoided. This thesis introduces a novel design of saturated-core FCLs which solves the problem of excessive weight of these devices. The new design utilizes design principle of insertion of an air gap in a core, typically used in design of inductors. Because of gap presence, the size of the core is approximately reduced by 70% in comparison to typical FCL design. The gap is inserted in such a way that it is a part of ac magnetic circuit but not a part of dc magnetic circuit. Thus, it is still possible to drive the core to saturation during normal operation. The new design uses one three-leg core per phase, where ac and dc windings are placed on outer legs. Based on the new core design, two FCL topologies are introduced: single-phase and three-phase FCL. Single-core FCL uses three cores for three phases whereas three-phase design utilizes only one core for all three phases. Therefore, the later topology reduces the amount of magnetic material further by more or less 66%. The drawback of three-phase FCL is that it limits only single-phase faults. The full voltage 10 kV/400 A prototype of three-phase FCL is built and tested. The measurements align very well with simulation results; they validate 3D FE transient model, built in Ansys, and prove the principle of operation.Electrical Sustainable Energy (EPP Group)Electrical Engineering, Mathematics and Computer Scienc
3D Nonlinear transies field-circuit modeling of inductive fault current limiters
Due to increasing levels of fault currents, Fault Current Limiters (FCLs) are expected to play an important role in the protection of future power grids. Inductive saturable FCLs are particularly interesting due to their inherent reaction on the fault. Many different configurations have been proposed in literature. Being difficult or impossible to create accurate analytical models of some FCL configurations, the development of Finite Element (FE) models for inductive FCLs is required. This paper presents a 3D nonlinear transient FE modeling technique applied to two inductive FCLs, namely so-called open-core and three-leg single-core FCLs. The models have been validated by comparing simulation results with lab measurements. Results show excellent agreement. The models constitute a valuable tool for design, optimization and verification of inductive FCLsDelft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
UBC Food Services : Increasing Food Skills in Residence
This intervention aimed to improve nutritional well being among students at the University of British Columbia (UBC). The target population was upper year students living in Walter Gage Residence (Gage) at UBC in Vancouver. The intervention was originally proposed by Melissa Baker, Manager, Nutrition and Wellbeing for UBC’s Student Housing & Hospitality Services and Katherine MacGregor, Residence Life Manager (RLM) of Gage. This project used Social Cognitive Theory (SCT) to assist in achieving the main objective of this intervention which was to create an instructional manual for residence advisors (RAs) to facilitate community kitchens (CKs) in Gage that improved attendees’ cooking capability, while building community.
Prior to beginning work on the project, a literature review was conducted to assess levels of food insecurity amongst university students, and to gain insight into effective interventions and programs of interest to the target population. Primary research (interviews) was conducted to assess the current level of food skills and knowledge of Gage residents. We found a combination of environmental, interpersonal and individual aspects that facilitate and mediate students’ food choices, and despite limited research, food insecurity among university students is present, and there is a need for increased food knowledge and skills in this population (Melissa Baker, personal communication, January 24, 2018).
Project outputs consisted of a CK manual to aid RAs in running CK programs in Gage and a post-intervention survey to evaluate the effectiveness of the intervention in increasing cooking confidence. The manual and survey will be passed along to community stakeholders for further analysis and used for expansion of this intervention to other residences. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”Land and Food Systems, Faculty ofUnreviewedUndergraduat