Tilstanden i sjøområdene ved Grimstad før start av biologisk renseanlegg på Groos

I 1995 ble Groosefjorden undersøkt for å dokumentere tilstanden før igangsetting av nytt biologisk renseanlegg. Det ble også gjort undersøkelser i andre kystområder i Grimstad kommune for å vurdere tilstanden. Undersøkelsene omfattet vannkjemiske målinger (oksygen, næringssalter, temperatur og saltholdighet), bløtbunnprøver, hardbunnundersøkelser (strandsone og dykk) samt undersøkelse av fiskeforekomster. Undersøkelsene viste at bunnområdene i Groosefjorden var tydelig påvirket av det kommunale utslippet på Groos. Bunnvannet hadde lave oksygenkonsentrasjoner og nær utslippet var bløtbunnsfaunaen dominert av arter som opptrer ved tung organisk belastning, men det var ingen større endringer i tilstanden siden forrige undersøkelse på 1980-tallet. Ved dykking ble det i tillegg registrert hydrogensulfid i sedimentene ved utslippspunktet. I overflatelaget ble det kun funnet svake effekter av utslippet. I Homborsund var det ingen større effekter av utslippet, men resultatene tyder på at området er sårbart for økning i tilførslene

Undersøkelse av resipientforholdene ved Narestø, Arendal kommune

Rapporten beskriver resipientforholdene i Narestøfjorden, og vurderer mulige konsekvenser av økning i det kommunale utslippet fra 70 pe til 3340 pe. Det er gjort undersøkelser av hydrografi (temperatur og saltholdighet), næringssalter, strøm, gruntvannsorganismer og bløtbunnsfauna. Videre er det foretatt beregninger av innlagringsdyp og fortynningsgrad ved ulike utslippsmengder og -dyp. Resultatene viste god vannutskiftning i overflatelaget ned til ca. 10 meter (oppholdstid 3-4 timer). Bunnvannet var ikke stagnerende, men hadde en noe lengre oppholdstid enn overflatevannet, ca. 1-2 døgn. Det var ingen tegn til effekter av dagens utslipp på strandsonen eller bløtbunnsfaunaen. Selv om det var mindre vannutskiftning i dypvannet, anbefales en utslippsløsning med utslippsdyp på 36 m, rørdiameter 150 mm og Y-formet ende-rør for det nye utslippet. Utslippet vil da innlagres i ca. 22 meters dyp, og det vil være liten sannsynlighet for gjennomslag til overflaten. Overflatevannet har i utgangspunktet noe høyt næringsinnhold

A development of logistics management models for the Space Transportation System

A new analytic queueing approach was described which relates stockage levels, repair level decisions, and the project network schedule of prelaunch operations directly to the probability distribution of the space transportation system launch delay. Finite source population and limited repair capability were additional factors included in this logistics management model developed specifically for STS maintenance requirements. Data presently available to support logistics decisions were based on a comparability study of heavy aircraft components. A two-phase program is recommended by which NASA would implement an integrated data collection system, assemble logistics data from previous STS flights, revise extant logistics planning and resource requirement parameters using Bayes-Lin techniques, and adjust for uncertainty surrounding logistics systems performance parameters. The implementation of these recommendations can be expected to deliver more cost-effective logistics support

Simulations of energetic beam deposition: from picoseconds to seconds

We present a new method for simulating crystal growth by energetic beam deposition. The method combines a Kinetic Monte-Carlo simulation for the thermal surface diffusion with a small scale molecular dynamics simulation of every single deposition event. We have implemented the method using the effective medium theory as a model potential for the atomic interactions, and present simulations for Ag/Ag(111) and Pt/Pt(111) for incoming energies up to 35 eV. The method is capable of following the growth of several monolayers at realistic growth rates of 1 monolayer per second, correctly accounting for both energy-induced atomic mobility and thermal surface diffusion. We find that the energy influences island and step densities and can induce layer-by-layer growth. We find an optimal energy for layer-by-layer growth (25 eV for Ag), which correlates with where the net impact-induced downward interlayer transport is at a maximum. A high step density is needed for energy induced layer-by-layer growth, hence the effect dies away at increased temperatures, where thermal surface diffusion reduces the step density. As part of the development of the method, we present molecular dynamics simulations of single atom-surface collisions on flat parts of the surface and near straight steps, we identify microscopic mechanisms by which the energy influences the growth, and we discuss the nature of the energy-induced atomic mobility

On the universality of compact polymers

Fully packed loop models on the square and the honeycomb lattice constitute new classes of critical behaviour, distinct from those of the low-temperature O(n) model. A simple symmetry argument suggests that such compact phases are only possible when the underlying lattice is bipartite. Motivated by the hope of identifying further compact universality classes we therefore study the fully packed loop model on the square-octagon lattice. Surprisingly, this model is only critical for loop weights n < 1.88, and its scaling limit coincides with the dense phase of the O(n) model. For n=2 it is exactly equivalent to the selfdual 9-state Potts model. These analytical predictions are confirmed by numerical transfer matrix results. Our conclusions extend to a large class of bipartite decorated lattices.Comment: 13 pages including 4 figure

The emotional power of poetry: Neural circuitry, psychophysiology, compositional principles

It is a common experience-and well established experimentally-that music can engage us emotionally in a compelling manner. The mechanisms underlying these experiences are receiving increasing scrutiny. However, the extent to which other domains of aesthetic experience can similarly elicit strong emotions is unknown. Using psychophysiology, neuroimaging, and behavioral responses, we show that recited poetry can act as a powerful stimulus for eliciting peak emotional responses, including chills and objectively measurable goosebumps that engage the primary reward circuitry. Importantly, while these responses to poetry are largely analogous to those found our music, their neural underpinnings show important differences, specifically with regard to the crucial role of the nucleus accumbens. We also go beyond replicating previous music-related studies by showing that peak aesthetic pleasure can co-occur with physiological markers of negative affect. Finally, the distribution of chills across the trajectory of poems provides insight into compositional principles of poetry

Bayesian Error Estimation in Density Functional Theory

We present a practical scheme for performing error estimates for Density Functional Theory calculations. The approach which is based on ideas from Bayesian statistics involves creating an ensemble of exchange-correlation functionals by comparing with an experimental database of binding energies for molecules and solids. Fluctuations within the ensemble can then be used to estimate errors relative to experiment on calculated quantities like binding energies, bond lengths, and vibrational frequencies. It is demonstrated that the error bars on energy differences may vary by orders of magnitude for different systems in good agreement with existing experience.Comment: 5 pages, 3 figure

Miljøstatus i vannforekomster i Aust-Agder. Del II. Marine resipienter

Rapporten gir en oppdatert oversikt over resipient- og miljøundersøkelser i sjøområdene i Aust-Agder. Hver av kystkommunene - Risør, Tvedestrand, Grimstad, Lillesand er behandlet separat. Oversikten er inndelt etter emnene tilførsler, hydrografi/hydrokjemi, plankton, hardbunnssamfunn, bløtbunnssamfunn, tarmbakterier og miljøgifter. Videre er det gitt en oversikt over tilstanden i de undersøkte områdene. I rapporten gis det en vurdering av de tidligere og igangværende undersøkelsene som grunnlag for fremtidige resipientundersøkelser og overvåking. Det blir også gitt anbefalinger om undersøkelser som kan samordnes mellom kommunene.Fylkesmannen i Aust-Agder, Miljøvernavdelinge

Interplay between quantum criticality and geometrical frustration in Fe3Mo3N with stella quadrangula lattice

In the eta-carbide-type correlated-electron metal Fe3Mo3N, ferromagnetism is abruptly induced from a nonmagnetic non-Fermi-liquid ground state either when a magnetic field (~14 T) applied to it or when it is doped with a slight amount of impurity (~5% Co). We observed a peak in the paramagnetic neutron scattering intensity at finite wave vectors, revealing the presence of the antiferromagnetic (AF) correlation hidden in the magnetic measurements. It causes a new type of geometrical frustration in the stellla quadrangula lattice of the Fe sublattice. We propose that the frustrated AF correlation suppresses the F correlation to its marginal point and is therfore responsible for the origin of the ferromagnetic (F) quantum critical behavior in pure Fe3Mo3N