146,447 research outputs found
An analysis of Gipps' car-following model of highway traffic
A mathematical analysis of Gipps's (1981) car?following model is performed. This model is of practical importance as it powers the UK Transport Research Laboratory highway simulation package SISTM. Uniform flow solutions and a speed–headway function are derived under simplifying conditions. A linear stability analysis of uniform flow is then performed, and stable and unstable regimes are identified. Finally, some numerical simulations for a variety of parameter regimes are presented. <br/
Automatic pump Patent
Automatically reciprocating, high pressure pump for use in spacecraft cryogenic propellant
Finite element analysis of compressible solids with nonlinear material properties
Finite-element computer program solves for nodal point displacements in an axisymmetric solid. The options in the program include plane stress analysis, axisymmetric solids analysis, nonlinear /plastic/ analysis, and equivalent stress and strain
Computer program calculates steady-state temperature distribution within plane or axisymmetric solids
Digital computer program, using the finite element analysis technique, determines the steady-state temperature within plan or axisymmetric solids composed of many different materials of various geometry. Program output is used to plot isotherms and provide data enabling the performance of stress analysis or heat transfer calculations upon the bodies
Steam Power Plants in Aircraft
The employment of steam power plants in aircraft has been frequently proposed. Arguments pro and con have appeared in many journals. It is the purpose of this paper to make a brief analysis of the proposal from the broad general viewpoint of aircraft power plants. Any such analysis may be general or detailed
Sir John Adams: his legacy to the world of particle accelerators
John Adams acquired an unrivalled reputation for his leading part in
designing and constructing the Proton Synchrotron (PS) in CERN's early days. In
1968, and after several years heading a fusion laboratory in the UK, he came
back to Geneva to pilot the Super Proton Synchrotron (SPS) project to approval
and then to direct its construction. By the time of his early death in 1984 he
had built the two flagship proton accelerators at CERN and, during the second
of his terms as Director-General, he laid the groundwork for the
proton-antiproton collider which led to the discovery of the intermediate
vector boson. How did someone without any formal academic qualification achieve
this? What was the magic behind his leadership? The speaker, who worked many
years alongside him, will discuss these questions and speculate on how Sir John
Adams might have viewed today's CERN.Comment: 29 pages, John Adams Memorial Lecture 2009, published with
high-resolution figures as CERN Yellow Report
http://cdsweb.cern.ch/record/133152
Onboard sampling and the rockfish and lingcod commerical passenger fishing vessel industry in Northern and Central California, January through December 1994
The Central California Marine Sport Fish Project has been collecting angler catch data on board Commercial Passenger Fishing Vessels (CPFVs) fishing for rockfish or lingcod since 1987. The program depends on the voluntary cooperation of CPFV owners and operators. This fourth report in a series presents data collected in 1994, refers to historical data from 1987 to 1993, and documents trends in species composition, angler effort, catch per unit effort (CPUE), and, for selected species, mean length and length frequency.
Angler catches on board central and northern California CPFVs were sampled from 14 ports, ranging from Crescent City in the north to Port San Luis (Avila Beach) in the south. Technicians observed a total of 2053 anglers fishing on 237
CPFV trips. These observed anglers caught 24,731 fish of which samplers determined 22,615 were kept. Over 63% of these fish were caught at Monterey or Morro Bay area ports.
Only 18 of the 53 species each comprised at least one percent of the catch. The top ten species in order of abundance were blue, yellowtail, rosy, chilipepper, canary, and black rockfishes, lingcod, and widow, starry and greenspotted rockfishes. Blue and yellowtail rockfishes
together comprised approximately 44% of the observed catch. Overall, rockfishes represented 32 species or 60% of the 53 identified species.
In general, 1994 data showed continued evidence of sustainability of the CPFV rockfish fishery with a few exceptions for some species in each port area sampled. We identified areas of concern for three nearshore species (black, blue, and brown rockfishes), three offshore species
(bocaccio, chilipepper, and widow rockfish), and two wide-depth range species (canary and yelloweye rockfishes). Declining trends in CPAH in at least one port area were identified for each of these species except black and blue
rockfishes, some of which may be related to natural variability in year class strength or stock movement. Mean length decreased in at least one port area for black, blue, brown, and canary rockfishes and chilipepper, although for black rockfish and chilipepper this was attributed to
increased recruitment of juveniles.
Positive trends identified included increased CPAH for black rockfish in the San Francisco and Monterey areas, for canary rockfish in the San Francisco area, and for brown rockfish in the Morro Bay area.
Total northern and central California CPFV catch estimates, based on logbook data and adjusted by sampling data and compliance rates, indicated that port area-specific decreases have occurred since 1988 for yellowtail rockfish and lingcod (San Francisco), chilipepper (Monterey),
and blue rockfish (Monterey and Morro Bay).
The competing influences of the nearshore commercial hook-and-line fishery were apparent when comparing relative species composition to that of the CPFV fishery. Declines in CPAH in the CPFV fishery for some shallow water species, such as brown rockfish in the Bodega Bay area, may be related to increased commercial fishing effort. (98pp.
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