9,618 research outputs found
Addressing the Multi-Channel Inverse Problem at High Energy Colliders: A Model Independent Approach to the Search for New Physics with Trileptons
We describe a method for interpreting trilepton searches at high energy
colliders in a model-independent fashion and apply it to the recent searches at
the Tevatron. The key step is to recognize that the trilepton signature is
comprised of four experimentally very different channels defined by the number
of tau-leptons in the trilepton state. Contributions from these multiple
channels to the overall experimental sensitivity (cross section times branching
ratio) are model-independent and can be parametrized in terms of relevant new
particle masses. Given the trileptonic branching ratios of a specific model,
these experimentally obtained multichannel sensitivities can be combined to
obtain a cross section measurement that can be used to confront the model with
data. Our model-independent results are more widely applicable than the current
Tevatron trilepton results which are stated exclusively in terms of mSUGRA
parameters of supersymmetry. The technique presented here can be expanded
beyond trilepton searches to the more general "inverse problem" of
experimentally discriminating between competing models that seek to explain new
physics discovered in multiple channels.Comment: 17 pages, 7 figures Changed content cosmetic changes for submission
to JHE
Magnetic Levitation for Long-Life Space Mechanisms: Technology Assessment and Remaining Challenges
Spacecraft mechanisms and mechanical systems must operate reliably and without failure to enable successful, long-term space missions. Such requirements place demands upon the tribological elements, especially bearings, which are frequently difficult or impossible to satisfy. Several recent, high-profile bearing failures in coolant fluid pumps and attitude control system (ACS) momentum wheels provided the impetus to assess the state-of-the-art non-contacting magnetic levitation-based, rotor support technologies.Magnetic levitation technology continues to gain acceptance for terrestrial applications and has been spaceflight demonstrated in mechanical systems such as reaction wheels (RWs) but is not in widespread use. The specific reasons inhibiting this new technology are not readily clear but include cost, weight, performance, and perceived risk. These reasons arise from a variety of real and perceived technical limitations in areas like materials, controls, sensors, thermal management and others. This white paper seeks to determine, define, and quantify the technical hurdles and gaps that must be overcome to enable the broad adoption of non-contacting bearings for long-life space mechanisms. It is anticipated that a better understanding of this complex topic may guide resource investments and clear the path to improved performance mechanical systems for spacecraft
Alien Registration- Dube, Marie A. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29471/thumbnail.jp
08/23/1947 Letter from Dirigo Aerie, No. 618
Letter from Rosario A. Dube, Chairman and Treasurer of the Fraternal Order of Eagles, Dirigo Aerie, No. 618, to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-1947-07-09/1025/thumbnail.jp
Assessment of Rock Pressure for Tunnels in the Himalayan Region — A Case History
Since early sixties numerous tunnels had been planned and constructed for hydro-electric power generation in the Himalayan Region of India. The mountain chain is of very recent origin geologically and is believed to be still active tectonically. The geology is complex and tunneling under such circumstances had been a real challenge. It was a tough task to predict the geotechnical behaviour of the tunneling media. Beginning with the classical approach of Terzaghi (1925-46) many rock pressure estimation theories had been evolved for prediction and estimation of rock pressure for designing competent and stable tunnel supports. The author has made an attempt to project real field data, which is rare to find, during a period of over thirty years of his association with the construction of numerous tunnels driven through diverse rock formations. Various theories in vogue for rock pressure assessment yielded different results. An attempt had also been made to reason out the differences. The rock pressure assessment is still a dark area, shaded darker when dealing with weak and very weak rock formations. It is believed that earthquakes affect the surface structures most but the sub surface structures are less affected. Some earthquakes occurring in India support this notion
Alien Registration- Dube, Marie A. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29471/thumbnail.jp
Alien Registration- Dube, Jules A. (Brunswick, Cumberland County)
https://digitalmaine.com/alien_docs/31454/thumbnail.jp
City Limits: What Do Local-Area Minimum Wages Do?
Cities are increasingly setting their own minimum wages, and this trend has accelerated sharply in recent years. While in 2010 there were only three cities with their own minimum wages exceeding the state or federal standard, by 2020 there were 42. This new phenomenon raises the question: is it desirable to have city-level variation in minimum wage polices? We discuss the main trade-offs emerging from local variation in minimum wage polices and evaluate their empirical relevance. First, we document what type of cities raise minimum wages, and we discuss how these characteristics can potentially impact the effectiveness of city-level minimum wage policies. Second, we summarize the evolving evidence on city-level minimum wage changes and provide some new evidence of our own. Early evidence suggests that the impact of the policy on wages and employment to date has been broadly similar to the evidence on state- and federal-level minimum wage changes. Overall, city-level minimum wages seem to be able to tailor the policy to the local economic environment without imposing substantial distortions in allocation of labor and businesses across locations
Oyster mushroom waste as manure in fish culture: a preliminary study
In an attempt to recycle the waste substrates of the oyster-mushroom crop, tanks were stocked with seed of Indian major carp Cirrhinus mrigala at the rate of 600,000/ha and waste substrate was applied at weekly interval at 0, 50, 100, 150, 200 and 250 g/tank. Oyster mushroom waste not only provided highly nutritive colonised detritus to the fish as direct feed, but also produced rich plankton in the tank. In waste treated tanks, production was better than in the control in 150, 200 and 250 g/tank treatment suggesting the possibility of fish-oyster mushroom integration
Chemical Speciation of Chromium in Various Matrices in South African Terrestrial Water Using an Optimised Adsorptive Stripping Voltammetric Procedure
Optimization of analytical procedure for the determination of chromium (III)/(VI) speciation is described. A very sensitive adsorptive-catalytic stripping voltammetry method in the presence of diethylenetriaminepentaacetic acid (DTPA) is used for chromium speciation study in surface and ground water with in very different matrices. The effects of various parameters (pH, ligand concentration, potential, collection time, equilibration time,) on the response are optimized. Concentration ratio of chromium (III)/(VI), and interferences from other metals and anions, typical for South African waters, are considered. Results for total chromium determination are compared with atomic absorption spectrometry (AAS) measurements.
South African Journal of Chemistry Vol.54 2001: 264-28
- …