Investigating Potential Improvements to Enhance the Performance of a Solar Thermal Collection System: Design of the Dual Axis Tracking System

Due to the current energy crisis, there are a large number of opportunities in the applications of renewable energy technologies. Specifically, my partner and I have explored those associated with a solar thermal collection dish. The sun, being a virtually limitless supply of energy, ought to be used to its fullest potential. This technology is designed to do just that. Using a concave reflective surface, the sun’s thermal energy is concentrated to a central location where it is then collected by a working fluid. This type of approach achieves very high temperatures and maximizes the effectiveness of the thermal energy collection process. In order for the dish to efficiently capture the sun’s thermal energy, a motorized solar tracking system first needed be implemented. Using photovoltaic sensors, one linear actuator, and one small gear-head motor, I was able to create a dual-axis system capable of tracking the sun’s movement in a smooth, controlled manner. The supporting structure itself is constructed from T-Slotted framing materials and rests atop a rolling cart for mobility. All phases of constructing and calibrating the system were completed by March 16th, 2012. Further system improvements and data collection exercises are now being explored by faculty and students

Investigating Potential Improvements to Enhance the Performance of a Solar Thermal Collection System: Design of the Dual Axis Tracking System

Due to the current energy crisis, there are a large number of opportunities in the applications of renewable energy technologies. Specifically, my partner and I have explored those associated with a solar thermal collection dish. The sun, being a virtually limitless supply of energy, ought to be used to its fullest potential. This technology is designed to do just that. Using a concave reflective surface, the sun’s thermal energy is concentrated to a central location where it is then collected by a working fluid. This type of approach achieves very high temperatures and maximizes the effectiveness of the thermal energy collection process. In order for the dish to efficiently capture the sun’s thermal energy, a motorized solar tracking system first needed be implemented. Using photovoltaic sensors, one linear actuator, and one small gear-head motor, I was able to create a dual-axis system capable of tracking the sun’s movement in a smooth, controlled manner. The supporting structure itself is constructed from T-Slotted framing materials and rests atop a rolling cart for mobility. All phases of constructing and calibrating the system were completed by March 16th, 2012. Further system improvements and data collection exercises are now being explored by faculty and students

Star-structured polyethylene nanoparticles via Pd-catalyzed living polymerization : synthesis, characterization, and catalytic applications.

The arm-first synthesis of large unimolecular star-structured polyethylene nanoparticles or SPE-NPs (MW > 1,000 kg/mol, PDI ≈ 1.1) joined by a cross-linked polynorbornadiene (PNBD) core is described in this thesis. SPE-NPs having high arm number (fn > 100) and tunable arm topologies (hyperbranched HBPE or linear-but-branched LBPE) are conveniently synthesized in a single reactor following four consecutive steps. In step 1, living ethylene polymerization is catalyzed by 0.1 mmol of Pd-diimine catalyst 1 to grow HBPE arms (1 atm C2H4/15 °C) or LBPE arms (27 atm C2H4/5 °C) of tunable lengths (tE = 1-5 h, Mn = 11-40 kg/mol). In step 2, the norbornadiene (NBD) cross-linker is added into the ethylene reactor for several hours (tNBD = 1-4 h) yielding PE-b-PNBD block copolymers with a short PNBD segment bearing cross-linkable pendant double bonds. SPEs are then formed in step 3 during precipitation in acidified methanol (H+/MeOH) and the final SPE-NPs are formed in step 4 after several hours of drying in vacuo at 120 °C. A thorough systematic investigation of the reaction parameters indicates that to produce increasingly larger SPE-NPs, it is essential to add a significant molar excess of NBD to 1 ([NBD]0/[1]0 > 50) and synthesize short LBPE arms but large HBPE arms. When synthesized with LBPE arms, the SPE-NPs have higher MW compared to those synthesized with HBPE arms due to the lower steric hindrance of the linear arms which enables a high number of arms to be joined at the PNBD core. Furthermore, the Pd-diimine catalyst used in the synthesis of the SPE-NPs was encapsulated within the cross-linked PNBD core. These encapsulated Pd(II) species were tested for their activity in hydrogenation reactions of terminal alkenes and alkynes (1-octene, 1-hexene, and 1-hexyne) and Heck coupling reactions of iodobenzene and n-butyl acrylate. Preliminary data suggests that these SPE-NPs may be used as models for the design of more advanced recyclable nanovessel for Pd(II) catalysts.Master's These

Impulse distributions in dense granular flows: signatures of large-scale spatial structures

In this paper we report the results of simulations of a 2D gravity driven, dissipative granular flow through a hopper system. Measurements of impulse distributions P(I) on the simulated system show flow-velocity-invariant behavior of the distribution for impulses larger than the average impulse . For small impulses, however, P(I) decreases significantly with flow velocity, a phenomenon which can be attributed exclusively to collisions between grains undergoing frequent collisions. Visualizations of the system also show that these frequently colliding particles tend to form increasingly large linear clusters as the flow velocity decreases. A model is proposed for the form of P(I), given distributions of cluster size and velocity, which accurately predicts the observed form of the distribution. Thus the impulse distribution provides some insight into the formation and properties of these ``dynamic'' force chains.Comment: 4 pages, 4 figure

Water Scarcity and Water Markets: A Comparison of Institutions and Practices in the Murray-Darling Basin of Australia and the Western US

Water markets in Australia’s Murray-Darling Basin (MDB) and the US west are compared in terms of their ability to allocate scarce water resources among competing uses. Both locations have been in the forefront of the development of water markets with defined water rights and conveyance structures to assist in the reallocation of water across competing demands. They also share the challenge of managing water with climate variability and climate change. As these two markets occur in developed, wealthy countries, their experiences in water markets with different water rights (appropriative, riparian and statutory rights) provide ‘best-case’ scenarios of what institutional arrangements work best, indicate which are less effective, and demonstrate what might be possible for greater use of water markets elsewhere in the world. The paper finds that the gains from trade in the MDB is worth hundreds of millions of dollars in per year, total turnover in water rights exceeds $2 billion per year and the volume of trade accounts for over 20$4.3 billion (2008 $) spent or committed by urban buyers between 1987 and 2008. Despite the clear benefits of water markets in both locations, there are on-going restrictions to trade that limit the potential gains and also third-party effects from use that require resolution.

A Comparative Assessment of Water Markets: Insights from the Murray-Darling Basin of Australia and the Western US

Water markets in Australia’s Murray-Darling Basin (MDB) and the US west are compared in terms of their ability to allocate scarce water resources. The study finds that the gains from trade in the MDB are worth hundreds of millions of dollars per year. Total market turnover in water rights exceeds $2 billion per year while the volume of trade exceeds over 20$4.3 billion (2008 $) spent or committed by urban buyers between 1987 and 2008. The two-market comparison suggests that policy attention should be directed towards ways to promote water trade while simultaneously mitigating the legitimate thirdparty concerns about how and where water is used, especially conflicts between consumptive and in situ uses of water. The study finds that institutional innovation is feasible in both countries and that further understanding about the size, duration, and distribution of third-party effects from water trade, and how these effects might be regulated, can improve water markets to better manage water scarcity.water markets, US west, Murray-Darling Basin, gains from trade