162 research outputs found
Bill Owens: A US Craft Beer Pioneer, 1982-2001
Bill Owens is a pioneer in the United States craft brewing industry through his efforts as an advocate, writer, publisher, brewer, and entrepreneur who created a lasting legacy by influencing generations of brewers and beer fans. Owens wrote the first book on homebrewing equipment (How to Build a Small Brewery: Draft Beer in Ten Days in 1982). He opened the third brewpub in the country (Buffalo Bill\u27s Brewery in Hayward, California in 1983) where, in 1985, he introduced the first commercial pumpkin beer among other beer style firsts. Owens published numerous brewery-focused magazines that featured many illustrious beer writers. This thesis explores Owens\u27 place in the history of food, drink, and culture
Cupric oxide-based p-type transparent conductors
This study examines the impact of doping on the resistivity of sputtered cupric oxide (CuO), and investigates the effects of co-sputtering CuO with tin dioxide (SnO2). It was found that films sputtered from a 2 at. % sodium-doped target have resistivities of four orders of magnitude lower than equivalent undoped films. Addition of oxygen was found to reduce the resistivity further. The best films were found to have resistivities of 4.3x10-2 Ω.cm. Co-sputtering with SnO2 was found to increase the band gap significantly, although it also caused an increase in the resistivity. All mixed oxide films were both amorphous and p-type
Using the Analytic Hierarchy Process to Assign Resources to Software Development Projects
This paper describes a real world case of the application of the analytic hierarchy process (AHP), a multi-criterion decision making approach, to the allocation of thousands of software developers to over a hundred development projects. The approach attempts to balance the value of each project to the business with the resources applied to it. Significant cost savings are expected to result from this approach
Optical optimization of perovskite solar cell structure for maximum current collection
High conversion efficiency has been recently demonstrated for Perovskite thin film photovoltaic devices. Perovskite thin film
solar cells are multilayer opto-electrical structures in which light interference occurs. This phenomenon can be used to maximise
the light transmission into the absorber material and increase the device efficiency. Fine tuning of the layer thicknesses within the stack can be used to control interference at the interfaces. Optical reflection losses can be reduced by achieving destructive
interference within the structure of the cell. The light transmission to the Perovskite absorber of a thin film solar cell on a fluorine doped tin oxide transparent conductor has been modelled using the transfer matrix method. Alternative transparent conductor materials have been also investigated including AZO and ITO. The modelling showed that replacing FTO with ITO could increase the photocurrent by as much as 4.5%. The gain can be further increased to 6.5% by using AZO as the TCO material.
Fine tuning of the TiO2 layer thickness can increase the current density by 0.3%. Furthermore, the current density of a Perovskite solar cell can be increased by application of a multilayer anti-reflective coating by another 3.5%. Optical optimisation of the stack design offers a significant increase in conversion efficiency
Combinatorial study of Sn-Ti-W-O transparent conducting oxide thin films for photovoltaic applications
a combinatorial study of transparent conducting oxide thin films based on SnO2–TiO2-WO3 phase space is reported. These multinary oxide films were fabricated by magnetron reactive co-sputtering of tin monoxide (SnO), titanium (Ti) and tungsten (W) targets. SnO2–TiO2-WO3 film compositions with Ti/Sn ratio (0.02 – 0.12) and W/(Ti+Sn) ratio (0.02 – 0.25) were explored. The effect of oxygen partial pressure on composition, structure and optical properties was evaluated. High optical transparency above 80% across the visible spectrum was obtained for sputtered ternary SnO2-TiO2 oxide films for oxygen partial pressure >19.4%. A positive correlation between optical bandgap and Ti/Sn ratio was observed. However, optical properties deteriorated as Ti-content increased in the as-deposited SnO2-TiO2-WO3 films. All studied as-deposited SnO2-TiO2-WO3 thin films were found to be highly resistive. X-ray diffraction data indicated no long-range structural order
A tunable amorphous p-type ternary oxide system: the highly mismatched alloy of copper tin oxide
The approach of combining two mismatched materials to form an amorphous alloy was used to synthesise ternary oxides of CuO and SnO2. These materials were analysed across a range of compositions, and the electronic structure was modelled using density functional theory. In contrast to the gradual reduction in optical band gap, the lms show a sharp reduction in both transparency and electrical resistivity with copper contents of greater than 50 %. Simulations indicate this change is caused by a transition from a dominant Sn
5s to Cu 3d contribution to the upper valence band. A corresponding decrease in energetic disorder results in increased charge percolation pathways: a `compositional mobility edge'. Contributions from Cu(II) sub band-gap states are responsible for the reduction in optical transparency
An infra-red reflecting optical coating for solar cover glass
A major problem with silicon solar cells is that they lose efficiency with increased operating temperature, at a rate of about 0.5% per 1â—¦C increase. This causes a significant reduction in power output, particularly in hot climates. A solution in the form of an optical coating is presented, which reflects infrared (IR) radiation to limit the module temperature increase. The optical coating is also anti-reflecting (AR) in the visible wavelength range, increasing the amount of light reaching the cell absorber. Modelling results show that the weighted average reflection (WAR) is reduced to 1.22% in the wavelength range associated with the band gap of silicon. The optical coating then reflects up to 70% of the infra-red. Although the model presented is based on silicon, the coating design can be modified to work with other photovoltaic technologies. The coating design uses only 4 layers and can be deposited using conventional high throughput magnetron sputtering systems already familiar to glass manufacturers. Preliminary work on optimising the coating deposition parameters is also presented here alongside modelling results. Deployment of the infra-red reflecting optical coating on solar cover glass represents a potential breakthrough in solar technology and will result in a significant increase in the power output of photovoltaic modules.<br
Evaluation of the role of hatch-spacing variation in a lack-of-fusion defect prediction criterion for laser-based powder bed fusion processes
Violation of Bell's Inequalities with a Local Theory of Photons
We use a local theory of photons purely as particles to model the
single-photon experiment proposed by Tan, Walls, and Collett. Like Tan et al.
we are able to derive a violation of Bell's inequalities for photon counts
coincidence measurements. Our local probabilistic theory does not use any
specific quantum mechanical calculations.Comment: LaTeX, 11 pages, one figure (in LaTeX), submitted to Foundations of
Physics Letter
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