Two-time scales inner solutions and motion of a geostrophic vortex

Based on the authors' previous work, in this paper the systematical analyses on the motion and the inner solutions of a geostrophic vortex have been presented by means of thematched asymptotic expansion method with multiple time scales (S/gh001/2 and α S/gh001/2) and space scales. It has been shown that the leading inner solutions to the core structure in two-time scales analyses are identified with the results in normal one-time scale analyses. The time averages of the first-order solutions on short time variable τ are the same as the first-order solutions obtained in one normal time scale analyses. The geostrophic vortex induces an oscillatory motion in addition to moving with the background flow. The period, amplitude andthe deviation from the mean trajectory depend on the core structure and the initial conditions. The velocity of the motion of vortex center varies periodically and the time average of the velocity on short time variable τ is equal to the value of the local mean velocity.

The Comovement between Monetary and Fiscal Policy Instruments during the Post-War Period in the U.S.

This paper empirically studies the dynamic relationship between monetary and fiscal policies by analyzing the comovements between the Fed funds rate and the primary deficit/output ratio. Simple economic thinking establishes that a negative correlation between Fed rate and deficit arises whenever the two policy authorities share a common stabilization objective. However, when budget balancing concerns lead to a drastic deficit reduction the Fed may reduce the Fed rate in order to smooth the impact of fiscal policy, which results in a positive correlation between these two policy instruments. The empirical results show (i) a significant negative comovement between Fed rate and deficit and (ii) that deficit and output gap Granger-cause the Fed funds rate during the post-Volcker era, but the opposite is not true.

The weevil-watermilfoil interaction at different spatial scales: what we know and what we need to know

The North American weevil ( Euhrychiopsis lecontei (Dietz)) is being considered as a biological control agent for Eurasian watermilfoil ( Myriophyllum spicatum L.). This native insect damages watermilfoil plants and is frequently associated with declining watermilfoil populations

“Deborah Numbers”, Coupling Multiple Space and Time Scales and Governing Damage Evolution to Failure

Two different spatial levels are involved concerning damage accumulation to eventual failure. nucleation and growth rates of microdamage nN* and V*. It is found that the trans-scale length ratio c*/L does not directly affect the process. Instead, two independent dimensionless numbers: the trans-scale one * * ( V*)including the * **5 * N c V including mesoscopic parameters only, play the key role in the process of damage accumulation to failure. The above implies that there are three time scales involved in the process: the macroscopic imposed time scale tim = /a and two meso-scopic time scales, nucleation and growth of damage, (* *4) N N t =1 n c and tV=c*/V*. Clearly, the dimensionless number De*=tV/tim refers to the ratio of microdamage growth time scale over the macroscopically imposed time scale. So, analogous to the definition of Deborah number as the ratio of relaxation time over external one in rheology. Let De be the imposed Deborah number while De represents the competition and coupling between the microdamage growth and the macroscopically imposed wave loading. In stress-wave induced tensile failure (spallation) De* < 1, this means that microdamage has enough time to grow during the macroscopic wave loading. Thus, the microdamage growth appears to be the predominate mechanism governing the failure. Moreover, the dimensionless number D* = tV/tN characterizes the ratio of two intrinsic mesoscopic time scales: growth over nucleation. Similarly let D be the “intrinsic Deborah number”. Both time scales are relevant to intrinsic relaxation rather than imposed one. Furthermore, the intrinsic Deborah number D* implies a certain characteristic damage. In particular, it is derived that D* is a proper indicator of macroscopic critical damage to damage localization, like D* ∼ (10–3~10–2) in spallation. More importantly, we found that this small intrinsic Deborah number D* indicates the energy partition of microdamage dissipation over bulk plastic work. This explains why spallation can not be formulated by macroscopic energy criterion and must be treated by multi-scale analysis.

Investigations of cohesive zone properties of the interface between metal film and ceramic substrate at nano- and micro-scales

Cohesive zone characterizations of the interface between metal film and ceramic substrate at micro- and nano-scales are performed in the present research. At the nano-scale, a special potential for special material interface (Ag/MgO) is adopted to investigate the interface separation mechanism by using MD simulation, and stress-separation relationship will be obtained. At the micro-scale, peeling experiment is performed for the Al film/Al2O3 substrate system with an adhesive layer at the interface. Adhesive is a mixture of epoxy and polyimide with mass ratio 1:1, by which a brittle cohesive property is obtained. The relationships between energy release rate, the film thickness and the adhesive layer thickness are measured during the steady-state peeling. The experimental result has a similar trend as modeling result for a weak adhesion interface case.

Cost effectiveness of a combination of instruments for global warming: a quantitative approach for Spain

Climate change is an important environmental problem and one whose economic implications are many and varied. This paper starts with the presumption that mitigation of greenhouse gases is a necessary policy that has to be designed in a cost effective way. It is well known that market instruments are the best option for cost effectiveness. But the discussion regarding which of the various market instruments should be used, how they may interact and what combinations of policies should be implemented is still open and very lively. In this paper we propose a combination of instruments: the marketable emission permits already in place in Europe for major economic sectors and a CO(2) tax for economic sectors not included in the emissions permit scheme. The study uses an applied general equilibrium model for the Spanish economy to compute the results obtained with the new mix of instruments proposed. As the combination of the market for emission permits and the CO(2) tax admits different possibilities that depend on how the mitigation is distributed among the economic sectors, we concentrate on four possibilities: cost-effective, equalitarian, proportional to emissions, and proportional to output distributions. Other alternatives to the CO(2) tax are also analysed (tax on energy, on oil and on electricity). Our findings suggest that careful, well designed policies are needed as any deviation imposes significant additional costs that increase more than proportionally to the level of emissions reduction targeted by the EU.

FORTH for NOAA/MLML Instruments

This report describes FORTH software written for several instruments used in the NASA-sponsored project to design and build Marine Optical Buoy System (MOBS) and in the NOAA-sponsored project "EOS MODIS Execution: Oceanographic Profiling, Data Acquisition and Management for the Marine Optical Buoy System·'. In the NOAA project MLML and NOAA personnel will participate in quarterly cruises at the MOBS Hawaiian site to validate performance of SeaWiFS and will participate in several extended "process" cruises to provide wide geographic surface truthing investigations similar to those lead by Dennis Clark (NOAA) following the "launch of CZCS in 1979. In the NASA project we are designing and building MOBS, a high resolution spectroradiometer that will operate autonomously in a buoy moored west of Lanai in the Hawaiian Islands. That instrument, the "Marine Optical System" (MOS), will transmit by cellular phone in near real time observations of upwelled radiance and downwelled irradiance from three depths. [PDF contains 90 pages]

Possible inclusion of fish waste (scales and fins) in the diet of fishes in aquaculture

The scales and fins of some freshwater fish species (Sarotherodon galilaeus, Oreochromis niloticus, Tilapia zillii, Barbus callipterus, Hemichromis fasciatus) from Kainji Lake, Nigeria were analyzed for their organic and inorganic matter. The aim of such study is to determine the usefulness of these waste parts of the fish in fish feed preparation. In all instances, the inorganic matter was found to be quite high in the fish exoskeleton, and calcium formed the highest element in the scales and the fins. These waste materials are therefore, considered as possible replacement for mineral sources in fish feed and probably the feed for other livestock