Inhomogeneous gas model for electron mobility in high density neon gas

Experimental studies of electron mobilities in Neon as a function of the gas density have persistently shown mobilities up to an order of magnitude smaller than expected and predicted. A previously ignored mechanism (gas in--homogeneity which is negligible in the thermal mobilities for He and other gases) is found to reproduce the observed Neon mobilities accurately and simply at five temperatures with just one variable parameter. Recognizing that a gas is not a homogeneous medium, a variation in local density combined with the quantum multi--scattering theory, shifts the energy and cross section -- which in turn changes the collision probability and finally the mobilities. A lower density where a momentum transfer interaction occurs moves the mobility strongly in the same direction as the anomalous experiments. By going backwards from the observed mobilities, the collision frequency at each temperature and density is made to reproduce the experimental data by looking for the local (as opposed to average) density at which the (rare) momentum transfer interactions occur. These density deviations give a picture of the size and behavior of the wave packets for electron motion which looks very much like the often discussed wave function collapse.Comment: 18 pages, 5 figure

CV19038

An acoustic survey of Atlantic herring Clupea harengus was conducted in ICES areas 6aS/7b in Dec 2019 using the research vessel RV Celtic Voyager and the fishing vessel MFV Ros Ard SO745. This survey is the fourth in a time series that is hoped will be developed into a long-term index of spawning/pre-spawning herring in 6aS/7b. The survey design is based on the predicted distribution of this winter spawning herring in this area. Poor weather negatively impacted the survey in 2019, resulting in fewer transect miles completed and fewer strata areas covered than planned. In total, approximately 600nmi of cruise track was completed using 96 transects. This resulted in a total area coverage of approximately 606 nmi², a significant reduction compared to recent years. Parallel transect spacing was set at 3.5nmi for the Donegal Bay strata. Tightly spaced zig-zag transects were used in a relatively small area in Lough Swilly. A Simrad ES-120 7CD (120 kHz) split-beam echosounder was used to collect acoustic raw data. The transducer was mounted on a towed body from the Celtic Voyager in Donegal Bay and was pole mounted from the Ros Ard in Lough Swilly. Very strong herring marks were evident in Lough Swilly in deepest part of the channel. The herring marks continued for many miles in the upper Swilly, an area where boats in the monitoring fishery had also concentrated effort. There were some herring marks in discreet areas around Drumanoo Head, Bruckless Bay and Inver Bay in the Donegal Bay Strata. Biological samples from the monitoring fishery of herring were used to augment the samples from the survey. Herring samples were taken from boats fishing in Lough Swilly and Inver Bay as close spatially and temporally as possible to the survey in these areas. Herring were dominated overall by 1- and 2-wr fish, (52% of the overall numbers) followed by relatively strong 3- and 5-wr cohorts. The total stock biomass (TSB) estimate of herring for the combined 6aS/7b area was 25,289 tonnes (Lough Swilly = 19,697 tonnes, Donegal Bay = 5,591 tonnes). This is considered to be a minimum estimate of herring in the 6aS/7b survey area at the time of the survey, and a significant decrease on the previous 3 years surveys. The reduction in the survey area completed as a consequence of the poor weather resulted in the survey not containing the stock in 2019. However, the overall CV estimate on biomass and abundance for the survey area completed is low (~0.17) in 2019. This is driven by the improved survey design in Lough Swilly, with reduced transect spacing and increased transect miles in this strata. The CV for the Donegal Bay strata is relatively high (0.63), this is mostly caused by the over-reliance on a few acoustic marks of herring in Bruckless and Inver Bays in particular and many transects with little or no herring marks. The survey in 2019 had to be altered due to weather, requiring a change in design and approach. However, the template of focusing on discreet areas was generally successful and may provide a template for future designs, particularly when reduced effort is necessary during poor weather or resource limits

Atlantic Herring and Horse Mackerel in 6aS/7b; Industry Acoustic Survey Cruise Report

An acoustic survey of Atlantic herring Clupea harengus and horse mackerel Trachurus trachurus was conducted in ICES areas 6aS/7b in Nov 2017 using the pair trawl vessels MFV Eilean Croine S238 and MFV Sparkling Star D437. This survey is the second in a time series that is hoped will be developed into a long-term index of spawning/pre-spawning herring and horse mackerel in 6aS/7b, for use in stock assessments in the future. The survey design was based on the predicted distribution of herring and horse mackerel in this area during this time. In total 1,482nmi of cruise track was completed using 27 transects and related to a total area coverage of approximately 2,200 nmi². Parallel transect spacing was set at 7.5nmi for the wider area, and 3.5nmi for Donegal Bay. Coverage extended from inshore coastal areas to the 200 m contour in the west and north. A mini survey was carried out in Lough Swilly using a zig-zag design. A Simrad ES-38B (38 kHz) split-beam transducer mounted on a towed body was calibrated before the survey near Rathmullan Pier in Lough Swilly, Co. Donegal. Very strong herring marks (e.g. > 2nmi long, 200m wide and ~18m deep) were evident in Lough Swilly, an area where boats in the monitoring fishery were concentrating effort. There was also a series of strong herring marks in Bruckless Bay and Inver Bay in discreet areas. There were very few herring marks offshore. A total of four hauls were taken for biological analysis. Biological samples from the monitoring fishery were used to augment the samples from the survey. Samples were taken from boats fishing in Lough Swilly, Bruckless Bay and Inver Bay as close spatially and temporally as possible to the survey in these areas. Herring were dominated by 3-wr fish in all hauls. The 3-wr age class constituted 32% of the overall numbers. Horse mackerel were distributed throughout the survey area, but particularly throughout the area to the north and west of Tory Island. Horse mackerel length distribution was dominated by a mode at 24cm, with a smaller mode at 30cm. This corresponded to a dominance of 3-wr fish (~67%) in all of the samples. The total stock biomass (TSB) estimate of herring for the combined 6aS/7b area was 40,646 tonnes (Lough Swilly = 12,098 tonnes, Donegal Bay = 23,157 tonnes, and the remaining NW area = 5,391 tonnes). This is considered to be a minimum estimate of herring in the 6aS/7b survey area at the time of the survey. The TSB estimate of horse mackerel for the total surveyed area in 6aS/7b area was 68,079 tonnes, considered to be a minimum estimate of horse mackerel in the 6aS/7b survey area at the time of the survey. The CV estimates on biomass and abundance are high (~0.50 for herring and ~ 0.62 for horse mackerel) for the survey in 2017. For herring, this is mostly caused by the over-reliance on a few acoustic marks of herring in Lough Swilly and Bruckless/Inver Bays in particular. For horse mackerel, this is most likely caused by and over-reliance of two transects in particular. Horse mackerel are a widely distributed stock, therefore the stock was not contained by this survey

The effect of Demand Response and wind generation on electricity investment and operation. ESRI Research Bulletin 2019/07

Concerns over climate change have led to an increase in renewable energy usage, particularly in the electricity sector. Given that the output from many renewable sources of energy, such as wind and solar, increases and decreases throughout the course of a day or week, there is a greater requirement for the rest of the electricity system to behave flexibly as renewable energy increases. Traditionally, electricity demand was considered fixed and power generation units, such as coal, gas and oil units, varied their supply to match supply and demand in realtime. However in recent years, there has been a new focus on the potential for electricity demand itself to become flexible or responsive by means of households and businesses increasing their electricity usage at times of high availability, and decreasing their usage at times of low availability

The impacts of demand response participation in capacity markets. ESRI Research Bulletin 2019/10

Electricity demand varies over the course of a day or a year, with very high levels of electricity demand being seen for only a few hours per year. However, there must be sufficient electricity generation installed on the system to meet the total demand at these few hours per year, in order to avoid blackouts or brownouts, where electricity supply is disconnected for all or some customers, respectively. As electricity generation from variable renewable sources, such as wind and solar, increases, electricity market revenues decrease, which renders conventional generators less profitable. In order to ensure that there is sufficient conventional generation available to meet demand at the hours of highest demand per year, a separate market payment is made to generators, called a capacity payment

Fisher Waves and Front Roughening in a Two-Species Invasion Model with Preemptive Competition

We study front propagation when an invading species competes with a resident; we assume nearest-neighbor preemptive competition for resources in an individual-based, two-dimensional lattice model. The asymptotic front velocity exhibits power-law dependence on the difference between the two species' clonal propagation rates (key ecological parameters). The mean-field approximation behaves similarly, but the power law's exponent slightly differs from the individual-based model's result. We also study roughening of the front, using the framework of non-equilibrium interface growth. Our analysis indicates that initially flat, linear invading fronts exhibit Kardar-Parisi-Zhang (KPZ) roughening in one transverse dimension. Further, this finding implies, and is also confirmed by simulations, that the temporal correction to the asymptotic front velocity is of ${\cal O}(t^{-2/3})$.Comment: 8 pages, 5 figures; Papers on related work can be found at http://www.rpi.edu/~korniss/Researc

Non-Adiabatic Potential-Energy Surfaces by Constrained Density-Functional Theory

Non-adiabatic effects play an important role in many chemical processes. In order to study the underlying non-adiabatic potential-energy surfaces (PESs), we present a locally-constrained density-functional theory approach, which enables us to confine electrons to sub-spaces of the Hilbert space, e.g. to selected atoms or groups of atoms. This allows to calculate non-adiabatic PESs for defined charge and spin states of the chosen subsystems. The capability of the method is demonstrated by calculating non-adiabatic PESs for the scattering of a sodium and a chlorine atom, for the interaction of a chlorine molecule with a small metal cluster, and for the dissociation of an oxygen molecule at the Al(111) surface.Comment: 11 pages including 7 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

Epitaxial checkerboard arrangement of nanorods in ZnMnGaO4 films studied by x-ray diffraction

The intriguing nano-structural properties of a ZnMnGaO4 film epitaxially grown on MgO (001) substrate have been investigated using synchrotron radiation-based x-ray diffraction. The ZnMnGaO4 film consisted of a self-assembled checkerboard (CB) structure with perfectly aligned and regularly spaced vertical nanorods. The lattice parameters of the orthorhombic and rotated tetragonal phases of the CB structure were analyzed using H-K, H-L, and K-L cross sections of the reciprocal space maps measured around various symmetric and asymmetric reflections of the spinel structure. We demonstrate that the symmetry of atomic displacements at the phases boundaries provides the means for coherent coexistence of two domains types within the volume of the film

Consistency and change in correlates of youth substance use, 1976-1997

https://deepblue.lib.umich.edu/bitstream/2027.42/137878/1/occ49.pd