Sustainable Building Techniques in Levi’s Stadium: A Case Study

This study aimed to analyze the sustainability of Levi’s Stadium in Santa Clara, California through an analysis of its Leadership in Energy and Environmental Design or LEED certification. Levi’s Stadium was the first professional sports stadium to receive LEED Gold certification in 2014, at a time where a focus on green building practices was becoming an industry standard. This analysis aims to determine what avenues the project team employed to ensure certification, including various standout features and strategies. Additionally, the study investigates the scorecard used to award points towards LEED certification, highlighting categories emphasized in design and construction and those that made less of a contribution to the point total. Finally, a more personal and detailed take on the process was collected through an interview with an employee that led sustainability efforts on the project. Through this analysis, the study intends to establish the pathway that a stadium project should take to find success in sustainability. With the information gathered, it was determined that the strategies Levi’s Stadium utilized were successful and trailblazing, and further case studies conducted on more recent professional sports stadiums would provide a clearer and more current picture of the recent landscape surrounding the sector

Ab initio study of the mechanism of carboxylic acids cross-ketonization on monoclinic zirconia via condensation to beta-keto acids followed by decarboxylation

Catalytic mechanism of acetic and isobutyric acids mixture conversion into two symmetrical and one cross-ketone product on monoclinic zirconia (111) surface was extensively modeled by Density Functional Theory for periodic structures. Several options were evaluated for each mechanistic step by calculating their reaction rate constants. The best option for each kinetically relevant step was chosen by matching calculated rates of reaction with experimental values. Four zirconium surface atoms define each catalytic site. The most favorable pathway includes condensation between surface carboxylates, one of which is enolized through alpha-hydrogen abstraction by lattice oxygen. Condensation of gas phase molecules with the enolized carboxylate on surface is less attainable. The kinetic scheme considers all steps being reversible, except for decarboxylation. The equilibrium constant of the enolization step and the rate constant of the condensation step define the global reaction rate for non-bulky acetic acid. For bulky isobutyric acid, decarboxylation step is added to the kinetic scheme as kinetically significant, while hydrocarbonate departure may also compete with the decarboxylation. Electronic and steric effect of alkyl substituents on the decarboxylation step is disclosed. The cross-selectivity is controlled by both condensation and decarboxylation steps. None of the mechanistic steps require metal oxide to be reducible/oxidizable

High accuracy switched-current circuits using an improved dynamic mirror

The switched-current technique, a recently developed circuit approach to analog signal processing, has emerged as an alternative/compliment to the well established switched-capacitor circuit technique. High speed switched-current circuits offer potential cost and power savings over slower switched-capacitor circuits. Accuracy improvements are a primary concern at this stage in the development of the switched-current technique. Use of the dynamic current mirror has produced circuits that are insensitive to transistor matching errors. The dynamic current mirror has been limited by other sources of error including clock-feedthrough and voltage transient errors. In this paper we present an improved switched-current building block using the dynamic current mirror. Utilizing current feedback the errors due to current imbalance in the dynamic current mirror are reduced. Simulations indicate that this feedback can reduce total harmonic distortion by as much as 9 dB. Additionally, we have developed a clock-feedthrough reduction scheme for which simulations reveal a potential 10 dB total harmonic distortion improvement. The clock-feedthrough reduction scheme also significantly reduces offset errors and allows for cancellation with a constant current source. Experimental results confirm the simulated improvements

Direkte numerische Simulation von Salzfingern = Direct numerical simulation of saltfingers / Thomas Zweigle

The phenomena of double-diffusive processes occur when two fluids with molecular diffusivities, operating on different scales, are combined. This process was recognized first by Arons and Stommel and later described with linear theory by Stern in 1960. A gravitationally stable fluid layer, with a stabilizing and a destabilizing component, is the initial state for double-diffusive processes. The release of potential energy by Doublediffusion results in destabilization of this layer. Instability develop and produce local fingerlike structures – the so called saltfingers. These lead to large scale convection of temperature and salinity that is direct against the stabilizing gradients. These kind of processes are not limited to ocean circulation only, Double-diffusion is also found in astrophysics (big Helium-stars), the earth core, metal alloy, refilling of gas reservoirs, etc. The main objective of this work is an estimation of the effective diffusivities of temperature and salinity, caused by saltfingering and is realized by means of direct numerical simulation (DNS). These effective diffusivities were used to compare the results with published values and test existing parametrisations. In this way, the effective diffusivity of temperature and salinity could be described by parametrisation. Also, the law of effective diffusivities by Merryfield was in well agreement with the effective fluxes, estimated in the salt-finger simulations of this work. Salt-finger processes were studied in several publications, but, semiconvection in the ocean was never modeled before by direct numerical simulation (DNS). Compared to saltfingering, semiconvection occurs as a process with a much more stable layering – with smaller thermohaline steps (0.5 − 5 m) in contrast to saltfingers (20 − 100 m) – and a narrow parameter range of stability. The developing of effective diffusivity by semiconvetion does not arrive at values of saltfingering

Reduction of blocking effects for the JPEG baseline image compression standard

Transform coding has been chosen for still image compression in the Joint Photographic Experts Group (JPEG) standard. Although transform coding performs superior to many other image compression methods and has fast algorithms for implementation, it is limited by a blocking effect at low bit rates. The blocking effect is inherent in all nonoverlapping transforms. This paper presents a technique for reducing blocking while remaining compatible with the JPEG standard. Simulations show that the system results in subjective performance improvements, sacrificing only a marginal increase in bit rate

FUSE Observations of Nebular O VI Emission from NGC 6543

NGC 6543 is one of the few planetary nebulae (PNe) whose X-ray emission has been shown to be extended and originate from hot interior gas. Using FUSE observations we have now detected nebular O VI emission from NGC 6543. Its central star, with an effective temperature of ~50,000 K, is too cool to photoionize O V, so the O VI ions must have been produced by thermal collisions at the interface between the hot interior gas and the cool nebular shell. We modeled the O VI emission incorporating thermal conduction, but find that simplistic assumptions for the AGB and fast wind mass loss rates overproduce X-ray emission and O VI emission. We have therefore adopted the pressure of the interior hot gas for the interface layer and find that expected O VI emission to be comparable to the observations.Comment: 4 pages, 4 figures, 1 table, using emulateapj.cls style. Accepted for publication in ApJ Letter

WELCHE FERNSEHSPOTS WIRKEN AM BESTEN?

Der Beitrag setzt sich mit dem Problem der Quantifizierung der Werbequalität auseinander. Angesichts des steilen Anstiegs der Ausgaben für Fernsehwerbung in der jüngeren Vergangenheit kommt der Betrachtung der Werbequalität heute eine vermehrte Bedeutung zu. Dieser Artikel befaßt sich mit Kriterien zur Beschreibung und Erfassung der qualitativen Gestaltung von Werbespots und untersucht darüber hinausgehend empirisch, ob bestimmte Gestaltungsformen wirksamer als andere sind. Es wird gezeigt, daß insbesondere TV-Spots, die ein Key-Visual (Schlüsselbild) verwenden, sowie TV-Spots mit Handlungsorientierung (d. h. die eine Geschichte erzählen) eine signifikant höhere Werbeeffizienz aufweisen. Zur Realisierung der Studie wurde zum einen auf das digitale Werbedokumentationssystem GfK-Digi*base sowie auf die Datenbank des Werbetracking-Systems der GfK (GfK-Werbindikator) zurückgegriffen

A proposal for a global task planning architecture using the RoboEarth cloud based framework

As robotic systems become more and more capable of assisting in human domains, methods are sought to compose robot executable plans from abstract human instructions. To cope with the semantically rich and highly expressive nature of human instructions, Hierarchical Task Network planning is often being employed along with domain knowledge to solve planning problems in a pragmatic way. Commonly, the domain knowledge is specific to the planning problem at hand, impeding re-use. Therefore this paper conceptualizes a global planning architecture, based on the worldwide accessible RoboEarth cloud framework. This architecture allows environmental state inference and plan monitoring on a global level. To enable plan re-use for future requests, the RoboEarth action language has been adapted to allow semantic matching of robot capabilities with previously composed plans

The evolution of M 2-9 from 2000 to 2010

M 2-9, the Butterfly nebula, is an outstanding representative of extreme aspherical flows. It presents unique features such as a pair of high-velocity dusty polar blobs and a mirror-symmetric rotating pattern in the inner lobes. Imaging monitoring of the evolution of the nebula in the past decade is presented. We determine the proper motions of the dusty blobs, which infer a new distance estimate of 1.3+-0.2 kpc, a total nebular size of 0.8 pc, a speed of 147 km/s, and a kinematical age of 2500 yr. The corkscrew geometry of the inner rotating pattern is quantified. Different recombination timescales for different ions explain the observed surface brightness distribution. According to the images taken after 1999, the pattern rotates with a period of 92+-4 yr. On the other hand, the analysis of images taken between 1952 and 1977 measures a faster angular velocity. If the phenomenon were related to orbital motion, this would correspond to a modest orbital eccentricity (e=0.10+-0.05), and a slightly shorter period (86+-5 yr). New features have appeared after 2005 on the west side of the lobes and at the base of the pattern. The geometry and travelling times of the rotating pattern support our previous proposal that the phenomenon is produced by a collimated spray of high velocity particles (jet) from the central source, which excites the walls of the inner cavity of M 2-9, rather than by a ionizing photon beam. The speed of such a jet would be remarkable: between 11000 and 16000 km/s. The rotating-jet scenario may explain the formation and excitation of most of the features observed in the inner nebula, with no need for additional mechanisms, winds, or ionization sources. All properties point to a symbiotic-like interacting binary as the central source of M 2-9.Comment: Accepted for publication on Astronomy and Astrophysics (10 pages, 8 figures