Cogeneration System Comparison for the Akron Water Treatment Plant

Cogeneration is a process of electrical power generation that simultaneously harnesses the heat produced from that electrical generation and uses it to supply heat to a space. The Akron Water Plant was identified as potentially benefitting from this technology for two main reasons. First, they have a large and relatively constant electrical load. Second, they have ownership of a significant amount of natural gas wells at the site. This report analyzes the economic feasibility of installing a cogeneration plant at the Akron Water Plant (AWP). Data was collected for the plant and its operations, including electricity bills, gas bills, plant layout, current heating and cooling methods, natural gas well capacities, and lease agreements. Based on this information, primarily the electrical consumption of the plant, cogenerators manufactured by 2G Energy were selected as the basis of design for the analysis. A cogeneration plant sized for the electrical consumption of the plant leads to significantly more waste heat than could be utilized to heat the AWP facilities. However, after studying the operation of the system, it became apparent that the cogenerator requires more fuel than the AWP wells have the capacity to produce. Nonetheless, the study was continued on the assumption that the wells did have the required capacity in order to study the economic feasibility of cogeneration systems in general. Price estimates were generated for each of the four proposed cogeneration configurations, including all costs required to update the plant from electric baseboard and gas heating to the hydronic heating provided by the cogenerator, and a payback analysis was performed to better understand the feasibility of each option. The results of this analysis are displayed in the table below. In conclusion, a cogeneration system may not be feasible for AWP due to the limited availability of natural gas; however, this study was useful in showing the feasibility of cogeneration plants as a concept. Should a facility have a larger gas well available, or even another fuel source capable of supplying the cogenerator, then cogeneration can provide enormous energy savings and appears to be a viable system

Vortex lattices in a stirred Bose-Einstein condensate

We stir with a focused laser beam a Bose-Einstein condensate of $^{87}$Rb atoms confined in a magnetic trap. We observe the formation of a single vortex for a stirring frequency exceeding a critical value. At larger rotation frequencies we produce states of the condensate for which up to eleven vortices are simultaneously present. We present measurements of the decay of a vortex array once the stirring laser beam is removed

Dynamic instability of a rotating Bose-Einstein condensate

We consider a Bose-Einstein condensate subject to a rotating harmonic potential, in connection with recent experiments leading to the formation of vortices. We use the classical hydrodynamic approximation to the non-linear Schr\"odinger equation to determine almost analytically the evolution of the condensate. We predict that this evolution can exhibit dynamical instabilities, for the stirring procedure previously demonstrated at ENS and for a new stirring procedure that we put forward. These instabilities take place within the range of stirring frequency and amplitude for which vortices are produced experimentally. They provide therefore an initiating mechanism for vortex nucleation.Comment: 4 pages, 3 figures, last version including comparison with experiment

Research Notes : The effect of added methionine on the growth and protein composition of soybean on cotyledons

Immature soybean cotyledons grow well in aseptic in vitro culture (Ann. Bot. 41: 29, 1977). The effect of adding methionine to a sulfuradequate medium was tested . Methionine caused a dry weight increase of 23%. Methionine also raised the methionine content of the protein by 22% and decreased the arginine content by 11 %

Generation and evolution of vortex-antivortex pairs in Bose-Einstein condensates

We propose a method for generating and controlling a spatially separated vortex--antivortex pair in a Bose-Einstein condensate trapped in a toroidal potential. Our simulations of the time dependent Gross-Pitaevskii equation show that in toroidal condensates vortex dynamics are different from the dynamics in the homogeneous case. Our numerical results agree well with analytical calculations using the image method. Our proposal offers an effective example of coherent generation and control of vortex dynamics in atomic condensates.Comment: 4 pages, 2 figure

Vortex Nucleation in a Stirred Bose-Einstein Condensate

We studied the nucleation of vortices in a Bose-Einstein condensate stirred by a laser beam. We observed the vortex cores using time-of-flight absorption imaging. By varying the size of the stirrer, we observed either discrete resonances or a broad response as a function of the frequency of the stirrer's motion. Stirring beams small compared to the condensate size generated vortices below the critical rotation frequency for the nucleation of surface modes, suggesting a local mechanism of generation. In addition, we observed the centrifugal distortion of the condensate due to the rotating vortex lattice and found evidence for bent vortices