Short-rotation forestry for energy production in Hawaii

Energy Technology Data Exchange (ETDEWEB)

Phillips, V.C.; Liu, W. [Univ. of Hawaii, Honolulu, HI (United States); Merriam, R.A.

1993-12-31

In Hawaii, imports of fossil fuels continue to accelerate and now provide over 90% of the total energy supply at a cost exceeding $1 {times} 10{sup 9} annually exported from the local economy. Concurrently, sugarcane and pineapple crops, the traditional mainstays of the state`s economy, have declined such that as much as 80,000 hectares of agricultural land are now available for alternative land uses. The feasibility of short-rotation forestry for sustainable energy production on these former sugarcane and pineapple plantation lands is being evaluated using species- and site-specific empirical models to predict yields of Eucalyptus grandis, E. saligna, and Leucaena leucocephala, a system model to estimate delivered costs, and a geographic information system to extend the analysis to areas where no field trials exist and to present results in map form. The island of Hawaii is showcased as an application of the methodology. Modeling results of methanol, ethanol, and electricity production from tropical hardwoods are presented. Short-rotation forestry appears to hold promise for the greening of Hawaii`s energy system and agricultural lands for the benefit of the state`s citizens and visitors. The methodology is readily transferable to other regions of the United States and rest of the world.

Economic investigations of short rotation intensively cultured hybrid poplars

Science.gov (United States)

David C. Lothner

1983-01-01

The history of the economic analyses is summarized for short rotation intensively cultured hybrid poplar at the North Central Forest Experiment Station. Early break-even analyses with limited data indicated that at a price of $25-30 per dry ton for fiber and low to medium production costs, several systems looked profitable. Later cash flow analyses indicated that two...

Short period tidal variations of earth rotation

Science.gov (United States)

Yoder, C. F.; Williams, J. G.; Parke, M. E.; Dickey, J. O.

1981-01-01

It is explained that the tidal deformation of the earth's polar moment of inertia by the moon and sun cause periodic variations in rotation. The short period oscillations give rise to a meter-sized, diurnal signature in the lunar laser ranging data obtained at McDonald Observatory. A solution is given for the scale parameter k/C at fortnightly and monthly tidal frequencies. The results are compared with those obtained by other investigators and with a theoretical estimate which includes the effect of oceans and a decoupled fluid core.

The Swedish energy forestry research programme at the Department of Short Rotation Forestry, SUAS, Uppsala. Summary report prepared for the evaluation of the short-rotation forestry research 1993-1996

Energy Technology Data Exchange (ETDEWEB)

Ledin, S.; Christersson, L. [eds.

1996-12-31

The overall aim of the Department of Short Rotation Forestry is to carry out research for development of basic, theoretical and practical knowledge in the related disciplines of biology, ecology and cultivation techniques in order to reach a high and sustainable production of woody biomass for energy purposes using environmentally acceptable methods. This report gives summaries of nine research programs within the Department, and the reports were prepared for the evaluation of the research during the period 1993-1996. The projects are: 1. Competition in short rotation forests (Theo Verwijst); 2. Carbon allocation as a function of nutrient and water availability (Lars Rytter, Tom Ericsson); 3. States and fluxes of water and carbon dioxide in the soil-plant-atmosphere system (Anders Lindroth); 4. Root dynamics of fast growing deciduous trees (Rose-Marie Rytter); 5. Accumulation and mobilization of root reserves in coppice growth (Lisa Sennerby-Forsse, Lars Bollmark, Yuehua von Fircks); 6. Effects of nutrient supply on frost resistance in fast growing Salix clones (Heinrich von Fircks); 7. Optimizing water and nutrients in poplar and willow plantations for maximum growth (Sune Elowson); 8. Soil biology in relation to energy forestry (Ulf Granhall); and 9. Plant protection in short rotation forestry against fungi and bacteria (Mauritz Ramstedt)

The silviculture, nutrition and economics of short rotation willow coppice in the uplands of mid-Wales

Energy Technology Data Exchange (ETDEWEB)

Heaton, R J; Randerson, P F; Slater, F M

2000-07-01

The potential of short rotation coppice as a biomass crop on land over 250m (the uplands) of mid Wales was studied. The results found in this study indicate that growing short rotation coppice willow in the uplands is a viable proposition with regard to establishment success and yields. In the event of a secure wood chip market in Wales, returns to the grower would be comparable to those from sheep production. (author)

Closed Loop Short Rotation Woody Biomass Energy Crops

Energy Technology Data Exchange (ETDEWEB)

Brower, Michael [CRC Development, LLC, Oakland, CA (United States)

2012-09-30

CRC Development LLC is pursuing commercialization of shrub willow crops to evaluate and confirm estimates of yield, harvesting, transportation and renewable energy conversion costs and to provide a diverse resource in its supply portfolio.The goal of Closed Loop Short Rotation Woody Biomass Energy Crops is supply expansion in Central New York to facilitate the commercialization of willow biomass crops as part of the mix of woody biomass feedstocks for bioenergy and bioproducts. CRC Development LLC established the first commercial willow biomass plantation acreage in North America was established on the Tug Hill in the spring of 2006 and expanded in 2007. This was the first 230- acres toward the goal of 10,000 regional acres. This project replaces some 2007-drought damaged acreage and installs a total of 630-acre new planting acres in order to demonstrate to regional agricultural producers and rural land-owners the economic vitality of closed loop short rotation woody biomass energy crops when deployed commercially in order to motivate new grower entry into the market-place. The willow biomass will directly help stabilize the fuel supply for the Lyonsdale Biomass facility, which produces 19 MWe of power and exports 15,000 pph of process steam to Burrows Paper. This project will also provide feedstock to The Biorefinery in New York for the manufacture of renewable, CO2-neutral liquid transportation fuels, chemicals and polymers. This project helps end dependency on imported fossil fuels, adds to region economic and environmental vitality and contributes to national security through improved energy independence.

THE SHORT ROTATION PERIOD OF HI’IAKA, HAUMEA’S LARGEST SATELLITE

Energy Technology Data Exchange (ETDEWEB)

Hastings, Danielle M.; Margot, Jean-Luc [University of California, Los Angeles, Department of Earth, Planetary, and Space Sciences, 595 Charles Young Drive East, Los Angeles, CA 90095 (United States); Ragozzine, Darin [Florida Institute of Technology, Department of Physics and Space Sciences, 150 West University Boulevard, Melbourne, FL 32901 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Burkhart, Luke D.; Holman, Matthew [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fuentes, Cesar [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Santiago (Chile); Brown, Michael E., E-mail: dhastings@g.ucla.edu [California Institute of Technology, Division of Geological and Planetary Sciences, MC 150-21, Pasadena, CA 91125 (United States)

2016-12-01

Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ∼9.8 hr (double peaked). This is ∼120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi’iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (currently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semimajor axis and rotation period in tidal evolution theory and find that they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do not necessarily lead to synchronous spin periods for Hi’iaka, even if it formed near the Roche limit. Therefore, the short rotation period of Hi’iaka does not rule out significant tidal evolution. Hi’iaka’s spin period is also consistent with formation near its current location and spin-up due to Haumea-centric impactors.

Growing short rotation coppice on agricultural land in Germany: A Real Options Approach

International Nuclear Information System (INIS)

Musshoff, Oliver

2012-01-01

In many cases decision-makers apparently do not adapt as fast as expected to changing economic conditions. This is also the case for the conversion of farm land to short rotation coppice. From an economic point of view, short rotation coppice has become more interesting in the last few years. Nevertheless, farm land still is rarely used to grow this quite unknown crop. Several explanatory approaches (e.g., traditionalistic behavior and risk aversion) are currently discussed in order to explain this behavior. A relatively new explanatory approach is the Real Options Approach. The Real Options Approach uses a comprehensive dynamic-stochastic model that combines the uncertainty of investment returns, the sunk costs, and the temporal flexibility of the investment implementation. The quintessence of the Real Options Approach is that—compared to the Classical Investment Theory—the investment triggers will be shifted upwards if investments involve intertemporal opportunity costs. This paper develops a real options model which allows the determination of triggers on the basis of realistic assumptions. We examined when farmers, who only dispose of sandy soils with little water-storing capacity, should convert set-aside land to short rotation coppice. The results show that farmers should not convert until the present value of the investment returns exceeds the investment costs considerably. Thus, they confirm the empirically observed reluctance in conversion. Furthermore, it turned out that the magnitude of the difference between the Classical Investment Theory and the Real Options Approach depends heavily on the type of stochastic process that underlies the investment returns. -- Highlights: ► Frequently observed reluctance of farmers to convert to short rotation coppice. ► Risk neutral farmers should convert if the investment multiple exceeds 1.57. ► The Real Options Approach is an explanatory approach for this observation. ► Results depend very much on the

Non-radial oscillations of rotating stars and their relevance to the short-period oscillations of cataclysmic variables

International Nuclear Information System (INIS)

Papaloizou, J.; Pringle, J.E.

1978-01-01

The usual hypothesis, that the short-period coherent oscillations seen in cataclysmic variables are attributable to g modes in a slowly rotating white dwarf, is considered. It is shown that this hypothesis is untenable for three main reasons: (i) the observed periods are too short for reasonable white dwarf models, (ii) the observed variability of the oscillations is too rapid and (iii) the expected rotation of the white dwarf, due to accretion, invalidates the slow rotation assumption on which standard g-mode theory is based. The low-frequency spectrum of a rotating pulsating star is investigated taking the effects of rotation fully into account. In this case there are two sets of low-frequency modes, the g modes, and modes similar to Rossby waves in the Earth's atmosphere and oceans, which are designated r modes. Typical periods for such modes are 1/m times the rotation period of the white dwarfs outer layers (m is the aximuthal wavenumber). It is concluded that non-radial oscillations of rotating white dwarfs can account for the properties of the oscillations seen in dwarf novae. Application of these results to other systems is also discussed. (author)

The potential for short-rotation woody crops to reduce US CO2 emissions

International Nuclear Information System (INIS)

Graham, R.L.; Wright, L.L.; Turhollow, A.F.

1992-01-01

Short-rotation woody crops (SRWC) could potentially displace fossil fuels and thus mitigate CO 2 buildup in the atmosphere. To determine how much fossil fuel SRWC might displace in the United States and what the associated fossil carbon savings might be, a series of assumptions must be made. These assumptions concern the net SRWC biomass yields per hectare (after losses); the amount of suitable land dedicated to SRWC production; wood conversion efficiencies to electricity or liquid fuels; the energy substitution properties of various fuels; and the amount of fossil fuel used in growing, harvesting, transporting, and converting SRWC biomass. Assuming the current climate, present production, and conversion technologies and considering a conservative estimate of the US land base available for SRWC (14 x 10 6 ha), it is calculated that SRWC energy could displace 33.2 to 73.1 x 10 6 Mg of fossil carbon releases, 3-6% of the current annual US emissions. The carbon mitigation potential per unit of land is larger with the substitution of SRWC for coal-based electricity production than for the substitution of SRWC-derived ethanol for gasoline. Assuming current climate, predicted conversion technology advancements, an optimistic estimate of the US land base available for SRWC (28 x 10 6 ha), and an optimistic average estimate of net SRWC yields (22.4 dry Mg/ha), it is calculate that SRWC energy could displace 148 to 242 x 10 6 Mg of annual fossil fuel carbon releases. Under this scenario, the carbon migration potential of SRWC-based electricity production would be equivalent to about 4.4% of current global fossil fuel emissions and 20% of current US fossil fuel emissions. 21 refs., 5 tabs

Carbon storage and recycling in short-rotation energy crops

International Nuclear Information System (INIS)

Ranney, J.W.; Wright, L.L.; Mitchell, C.P.

1991-01-01

Short-rotation energy crops can play a significant role in storing carbon compared to the agricultural land uses they would displace. However, the benefits from these plantations in avoiding further use of fossil fuel and in taking pressure off of native forests for energy uses provides longer term carbon benetfits than the plantation carbon sequestration itself. The fast growth and harvest frequency of plantations tends to limit the amount of above and below-ground carbon storage in them. The primary components of plantation carbon sequestering compared to sustained agricultural practices involve above-ground wood, possible increased soil carbon, litter layer formation, and increased root biomass. On the average, short-rotation plantations in total may increase carbon inventories by about 30 to 40 tonnes per hectare over about a 20- to 56-year period when displacing cropland. This is about doubling in storage over cropland and about one-half the storage in human-impacted forests. The sequestration benefit of wood energy crops over cropland would be negated in about 75 to 100 years by the use of fossil fuels to tend the plantations and handle biomass. Plantation interactions with other land uses and total landscape carbon inventory is important in assessing the relative role plantations play in terrestrial and atmospheric carbon dynamics. It is speculated that plantations, when viewed in this context. could trencrate a global leveling of net carbon emissions for approximately 10 to 20 years

Life-cycle assessment of eucalyptus short-rotation coppices for bioenergy production in Southern France

OpenAIRE

Gabrielle , Benoit; Nguyen The , Nicolas; Maupu , Pauline; Vial , Estelle

2011-01-01

Short rotation coppices (SRCs) are considered prime candidates for biomass production, yielding good-quality feedstock that is easy to harvest. Besides technical, social and economical aspects, environmental issues are important to take into account when developing SRCs. Here, we evaluated the environmental impacts of delivering 1 GJ of heat from eucalyptus SRC using life cycle assessment (LCA), based on management scenarios involving different rotations lengths, fertilizer input rates, stem ...

Local instabilities in magnetized rotational flows: A short-wavelength approach

OpenAIRE

Kirillov, Oleg N.; Stefani, Frank; Fukumoto, Yasuhide

2014-01-01

We perform a local stability analysis of rotational flows in the presence of a constant vertical magnetic field and an azimuthal magnetic field with a general radial dependence. Employing the short-wavelength approximation we develop a unified framework for the investigation of the standard, the helical, and the azimuthal version of the magnetorotational instability, as well as of current-driven kink-type instabilities. Considering the viscous and resistive setup, our main focus is on the cas...

Development of short-rotation willow coppice systems for environmental purposes in Sweden

International Nuclear Information System (INIS)

Mirck, Jaconette; Verwijst, Theo; Isebrands, J.G.; Ledin, Stig

2005-01-01

During the last three decades, driving forces behind the development of short-rotation willow coppice (SRWC) in Sweden have been changing from a primary focus on biomass production towards emphasis on environmental applications. In most cases, current commercial SRWC practice is geared towards a combination of biomass production for energy purposes and environmental goals. The latter goals range from decreasing the impact of specific contaminants in the environment to organic waste handling in a recycling system in urban and/or agricultural areas. Where biomass production and pollutant management overlap, the science of phytoremediation has its practical application. Through phytoremediation, waste products that previously have been a burden for society can be used as valuable resources to increase short-rotation willow biomass production. In this paper we will present the terminology and definitions of different types of phytoremediation. We also give an overview of five different cases of phytoremediation activities with a potential for large-scale implementation. Some of the types of activities are already commercially used in Sweden; others seem promising but still need further development. (Author)

Environmental effects of energy forest (short rotation willow)

International Nuclear Information System (INIS)

Frank, K.

1994-01-01

This paper deals with environmental effects of producing and combusting energy forest fuel. Energy forest means short rotation willow (Salix). Supposed effects of sewage sludge application are discussed as well. Energy forestry on agricultural land implies both advantages and disadvantages for the environment. Leaf litter (humified leaves) increases the humus content in the top soil. The soil fauna is also positively affected. Until now performed studies about nitrogen leakage from fields cultivated with energy forest (Salix), have not given any distinct results. A retarded drainage within energy forest fields is on the other hand noticed. While the root system of Salix is active during a long period of the year, the nitrogen leakage become less compared to traditional cultivation. The content of plant nutrients and organic matter in sewage sludge make a resource that can be useful for agricultural purposes, especially for energy forest cultivation. The content of heavy metals and organic emissions contradicts sludge application to agricultural land. Sewage sludge with todays quality increases somewhat the content of heavy metals in the soil. This condition can be counteracted to a certain extent by growing energy forest. It has been established that Salix has high ability to heavy metal uptake, especially cadmium. Growing energy forest on drained farm land is connected with a risk for root penetration into the drainage system. With enough water and plant nutrients in the top soil the risk is reduced. Shallow depth of the pipes increases the risk. Combustion of wood chip from energy forests (and other types of biomass) gives especially two advantages. It does not give any net contribution of carbon dioxide to the atmosphere. The sulphur discharge will be minimal since the sulphur content in wood fuels is low. Discharge of nitrogen oxide and hydrocarbons may give some problems. These can be reduced by technological measures when combusting. 27 refs, 4 tabs

Short rotation coppice as a business field of an energy utility

Energy Technology Data Exchange (ETDEWEB)

Cremer, T. (RWE Innogy Cogen GmbH, Dortmund (Germany))

2010-07-01

Companies that start planting short rotation coppice (SRC), enter a new territory. In fact, this subject is often discussed, but there is - at least in Germany - still comparatively little practical knowledge on that. Since ca. 1 year, RWE Innogy Cogen is doing pioneer work here and starts establishing SRC in Germany and Europe. Therefore, first results and experiences, as well as consequences for practice shall be presented and discussed in this article. (orig.)

Energy valorization of the species used in short-rotation plantations

International Nuclear Information System (INIS)

Moya Roque, Roger; Tenorio Monge, Carolina; Salazar Zeledon, Estephania

2016-01-01

The energy potential of some non-traditional plantations for production of energy is exposed. Forest and forage species are utilized in Costa Rica for energy plantations. The characteristics of these species have been short rotation (1-3 years) and a production between 20 and 25 tonnes of dry matter per hectare. Agro-energy plantations are described. Gmelina arborea y Pennisetum purpureum species have been viable options for biomass production. However, the high cost of seedlings and land to cultivate have been one of the problems of this energy source [es

Rotational Rebound Attacks on Reduced Skein

DEFF Research Database (Denmark)

Khovratovich, Dmitry; Nikolić, Ivica; Rechberger, Christian

2014-01-01

ciphers, including the new standard SHA-3 (Keccak). The rebound attack is a start-from-the-middle approach for finding differential paths and conforming pairs in byte-oriented designs like Substitution-Permutation networks and AES. We apply our new compositional attack to the reduced version of the hash...... number of rounds. We also use neutral bits and message modification methods from the practice of collision search in MD5 and SHA-1 hash functions. These methods push the rotational property through more rounds than previous analysis suggested, and eventually establish a distinguishing property...

Short-rotation coppicing in France. Current state of research and prospects for future development

Energy Technology Data Exchange (ETDEWEB)

Bonduelle, P. (Association Foret Cellulose, Trelaze (France)); Bouvarel, L. (Institut National de la Recherche Agronomique, Olivet (France). Unite Experimentale Biomasse, Forestiere et Foret Paysanne); Petit, H. (Association pour la Rationalisation et la Mecanisation de l' Exploitation Forestiere, Fontainebleau (France)); Pierson, J. (Cellulose des Ardennes, Montemedy (France)); Savanne, D. (Agence de l' Environnement et de la Maitrise de l' Energie, 75 - Paris (France)); Sourie, J.C. (Institut National de la Recherche Agronomique, Grignon (France). Station d' Economie et de Sociologie Rurales)

1992-01-01

This article analyzes the current context and the prospects for crop development as well as offering a number of examples of short rotation coppicing projects. The industrial outlets created through state aid remain the primary driving force behind plantations at this time. (author)

Theoretical background to and practical utilization of short-rotation and energy forestry

International Nuclear Information System (INIS)

Christersson, L.

1999-01-01

This paper gives an overview of activities within short-rotation forestry in Sweden. The main interest lies in plantations of alder, poplar and birch and the study also mentions the industrial value of these tree species, especially for the pulp and paper, and furniture sector. The environmental impact of deciduous tree plantations as well as the possibility of waste water treatment is also discussed

Short rotation coppice for energy production: hydrological guidelines

Energy Technology Data Exchange (ETDEWEB)

Hall, R.L.

2003-07-01

This report provides hydrological guidelines for growers, land and water resource managers, environmental groups and other parties interested in utilising short rotation coppice (SRC) for energy production. The aim of the report is to help interested parties decide if a location is suitable for SRC planting by considering whether potential hydrological impacts will have an adverse effect on crop productivity and yield. The guidelines consider: the water use of SRC compared with other crops; the factors governing water use; the water requirements for a productive crop; and the likely impacts on the availability and quantity of water. The report points out that there are still gaps in our knowledge of the processes controlling the water use and growth of SRC and notes that, in some situations, there will be considerable uncertainty in predictions.

Short-rotation forestry as an alternative land use in Hawaii

International Nuclear Information System (INIS)

Phillips, V.D.; Wei Liu; Merriam, R.A.

1995-01-01

The traditional mainstays of Hawaii's economy: sugarcane and pineapple crops, have declined such that as much as 80,000 hectares of agricultural land are now available for alternative land uses. Concurrently, imports of fossil fuels continue to accelerate and now provide over 90% of the total energy supply at a cost exceeding 1 billion dollars annually exported from the local economy. The feasibility of short-rotation forestry on these former sugarcane and pineapple plantation lands to produce a variety of wood products, including biofuels, is being evaluated using a species- and site-specific empirical model to predict yields of Eucalyptus saligna, a system model to estimate delivered costs of wood chips to a bioconversion facility, and a geographic information system to extend the analysis to areas where no field trials exist and to present results in map form. The island of Hawaii is showcased as an application of the methodology. Modelling results are presented for using tropical hardwoods as dedicated feedstocks from biomass energy plantations to produce methanol, ethanol and electricity. A hypothetical, integrated, high-value hardwood, veneer, utility lumber and wood-chip operation is featured in contrast to the biomass energy plantation scenario. Short-rotation forestry may hold some promise for the greening of Hawaii's energy system and even greater promise for the industrial production of value-added wood products for the benefit of the state's citizens and visitors. The methodology is readily transferable to other regions of the United States and the rest of the world. (author)

Short-rotation forestry as an alternative land use in Hawaii

Energy Technology Data Exchange (ETDEWEB)

Phillips, V.D.; Wei Liu [Hawaii Univ., Honolulu, HI (United States). Coll. of Tropical Agriculture and Human Resources; Bain, R.L. [National Renewable Energy Lab., Golden, CO (United States); Merriam, R.A.

1995-12-31

The traditional mainstays of Hawaii`s economy: sugarcane and pineapple crops, have declined such that as much as 80,000 hectares of agricultural land are now available for alternative land uses. Concurrently, imports of fossil fuels continue to accelerate and now provide over 90% of the total energy supply at a cost exceeding 1 billion dollars annually exported from the local economy. The feasibility of short-rotation forestry on these former sugarcane and pineapple plantation lands to produce a variety of wood products, including biofuels, is being evaluated using a species- and site-specific empirical model to predict yields of Eucalyptus saligna, a system model to estimate delivered costs of wood chips to a bioconversion facility, and a geographic information system to extend the analysis to areas where no field trials exist and to present results in map form. The island of Hawaii is showcased as an application of the methodology. Modelling results are presented for using tropical hardwoods as dedicated feedstocks from biomass energy plantations to produce methanol, ethanol and electricity. A hypothetical, integrated, high-value hardwood, veneer, utility lumber and wood-chip operation is featured in contrast to the biomass energy plantation scenario. Short-rotation forestry may hold some promise for the greening of Hawaii`s energy system and even greater promise for the industrial production of value-added wood products for the benefit of the state`s citizens and visitors. The methodology is readily transferable to other regions of the United States and the rest of the world. (author)

The economic impacts of federal tax reform for investments in short-rotation forest plantations

International Nuclear Information System (INIS)

Siegel, W.C.

1991-01-01

In discussing the potential contributions of short-rotation forest plantations to the fuel wood supply, a number of economic factors have been considered and analyzed. Very little, however, has been written on the income tax aspects of the subject. The tax treatment of such plantings is an extremely important factor. The federal income tax, in particular, can have a significant impact on production costs and is a major factor in determining the economic feasibility of this type of investment. The major federal Income tax provisions of significance are those that deal with capital expenditures, currently deductible costs and sale receipts. Several alternative tax approaches were available prior to passage of the 1986 Tax Reform Act. The new act's provisions, however, have completely changed the federal income tax treatment of timber income and expenditures, including those associated with short-rotation plantations. This paper analyzes the changes and discusses their economic implications for fuel wood culture

Effect of biomass pretreatment on the product distribution and composition resulting from the hydrothermal liquefaction of short rotation coppice willow

DEFF Research Database (Denmark)

Grigoras, Ionela; Stroe, Rodica-Elisabeta; Sintamarean, Iulia-Maria

2017-01-01

A major challenge for the implementation of hydrothermal liquefaction (HTL) as a continuous process is the formulation of lignocellulosic feedstock, which is prone to phase separation into water and biomass parts when pressurized. One approach to remedy such phase separation is to reduce the dry...... from the HTL of willow and proposes short rotation coppice as an alternative biomass feedstock for biofuels production. Alkaline–thermal pretreatment, besides making high dry matter pumpable feedstock slurries, also led to an increase in the production of the bio-crude product with an oxygen content...

Scientific Basis for Sustainable Management of Eucalyptus and Populus as Short-Rotation Woody Crops in the U.S.

Directory of Open Access Journals (Sweden)

Eric D. Vance

2014-05-01

Full Text Available Short rotation woody crops (SRWC, fast growing tree species that are harvested on short, repeated intervals, can augment traditional fiber sources. These crops have economic and environmental benefits stemming from their capability of supplying fiber on a reduced land base in close proximity to users and when sensitive sites cannot be accessed. Eucalyptus and Populus appear to be genera with the greatest potential to provide supplemental fiber in the U.S. Optimal productivity can be achieved through practices that overcome site limitations and by choosing the most appropriate sites, species, and clones. Some Eucalyptus species are potentially invasive, yet field studies across multiple continents suggest they are slower to disperse than predicted by risk assessments. Some studies have found lower plant and animal diversity in SRWC systems compared to mature, native forests, but greater than some alterative land uses and strongly influenced by stand management, land use history, and landscape context. Eucalyptus established in place of grasslands, arable lands, and, in some cases, native forests can reduce streamflow and lower water tables due to higher interception and transpiration rates but results vary widely, are scale dependent, and are most evident in drier regions.

Short rotation coppice as a fuel: framework for a contractual infrastructure

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

This report summarises the results of a study exploring the contractual interface between growers and suppliers of short rotation coppice fuels and power generators in England and Wales, France and Sweden. Reviews of the main contractual considerations in relation to growers and generators in the UK, and Swedish and UK studies are presented. Proposals for the contractual treatment in the UK of the issues raised by the studies are considered, and recommendations for the treatment of contractual and economic requirements prevailing in France and Sweden are given. Appendices contains model agreements. (UK)

Increasing the productivity of short-rotation Populus plantations. Final report

Energy Technology Data Exchange (ETDEWEB)

DeBell, D.S.; Harrington, C.A.; Clendenen, G.W.; Radwan, M.A.; Zasada, J.C. [Forest Service, Olympia, WA (United States). Pacific Northwest Research Station

1997-12-31

This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. Seven research papers are included which provide detailed methods, results, and interpretations on these topics.

Natural flood retention in mountain areas by forests and forest like short rotation coppices

Science.gov (United States)

Reinhardt-Imjela, Christian; Schulte, Achim; Hartwich, Jens

2017-04-01

Natural water retention is an important element of flood risk management in flood generating headwater areas in the low mountain ranges of Central Europe. In this context forests are of particular interest because of the high infiltration capacities of the soils and to increase water retention reforestation of agricultural land would be worthwhile. However competing claims for land use in intensely cultivated regions in Central Europe impede reforestation plans so the potential for a significant increase of natural water retention in forests is strongly limited. Nevertheless the development of innovative forms of land use and crop types opens new perspectives for a combination of agricultural land use with the water retention potential of forests. Recently the increasing demand for renewable energy resources leads to the cultivation of fast growing poplar and willow hybrids on agricultural land in short rotation coppices (SRC). Harvested in cycles of three to six years the wood from the plantations can be used as wood chips for heat and electricity production in specialized power plants. With short rotation plantations a crop type is established on arable land which is similar to forests so that an improvement of water retention can be expected. To what extend SRC may contribute to flood attenuation in headwater areas is investigated for the Chemnitzbach watershed (48 km2) in the Eastern Ore Mountains (Free State of Saxony, Germany), a low mountain range which is an important source of flood runoff in the Elbe basin. The study is based on a rainfall-runoff model of flood events using the conceptual modelling system NASIM. First results reveal a significant reduction of the flood peaks after the implementation of short rotation coppices. However the effect strongly depends on two factors. The first factor is the availability of areas for the plantations. For a substantial impact on the watershed scale large areas are required and with decreasing percentages of SRC

Generalized allometric regression to estimate biomass of Populus in short-rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Ben Brahim, Mohammed; Gavaland, Andre; Cabanettes, Alain [INRA Centre de Toulouse, Castanet-Tolosane Cedex (France). Unite Agroforesterie et Foret Paysanne

2000-07-01

Data from four different stands were combined to establish a single generalized allometric equation to estimate above-ground biomass of individual Populus trees grown on short-rotation coppice. The generalized model was performed using diameter at breast height, the mean diameter and the mean height of each site as dependent variables and then compared with the stand-specific regressions using F-test. Results showed that this single regression estimates tree biomass well at each stand and does not introduce bias with increasing diameter.

Quality Testing of Short Rotation Coppice Willow Cuttings

Directory of Open Access Journals (Sweden)

Katrin Heinsoo

2018-06-01

Full Text Available The production and feasibility of Short Rotation Coppice depend on cutting early performance. The shoot and root biomass production of Salix cuttings in hydroponic conditions was studied. The amount of sprouted biomass after four weeks of growth depended on cutting the diameter, but the original position of the cutting along the rod or number of visible buds was not in correlation with biomass produced. Application of mineral fertilizer or soil originating from the willow plantation did not increase the total production. On the contrary, the addition of soil tended to decrease biomass production and we assumed this was a result of a shortage of light. Under the influence of fertilization, plants allocated greater biomass to roots. Comparison of different clones revealed that those with S. dasyclados genes tended to allocate less biomass to roots and the poorest-performing clone in our experiment, also had the lowest wood production in the plantation. The number of visible buds on the cutting was also clone-specific.

A rotating bluff-body disc for reduced variability in wind tunnel aerosol studies.

Science.gov (United States)

Koehler, Kirsten A; Anthony, T Renee; van Dyke, Michael; Volckens, John

2011-01-01

A rotating bluff-body disc (RBD) was developed to reduce spatiotemporal variability associated with sampling supermicron aerosol in low-velocity wind tunnels. The RBD is designed to rotate eight personal aerosol samplers around a circular path in a forward-facing plane aligned with the wind tunnel cross section. Rotation of the RBD allows each sampler to traverse an identical path about the wind tunnel cross section, which reduces the effects of spatial heterogeneity associated with dispersing supermicron aerosol in low-velocity wind tunnels. Samplers are positioned on the face of the RBD via sampling ports, which connect to an air manifold on the back of the disc. Flow through each sampler was controlled with a critical orifice or needle valve, allowing air to be drawn through the manifold with a single pump. A metal tube, attached to this manifold, serves as both the axis of rotation and the flow conduction path (between the samplers and the vacuum source). Validation of the RBD was performed with isokinetic samplers and 37-mm cassettes. For facing-the-wind tests, the rotation of the RBD significantly decreased intra-sampler variability when challenged with particle diameters from 1 to 100 μm. The RBD was then employed to determine the aspiration efficiency of Institute of Occupational Medicine (IOM) personal samplers under a facing-the-wind condition. Operation of IOM samplers on the RBD reduced the between-sampler variability for all particle sizes tested.

Meeting the demand for crop production: the challenge of yield decline in crops grown in short rotations.

Science.gov (United States)

Bennett, Amanda J; Bending, Gary D; Chandler, David; Hilton, Sally; Mills, Peter

2012-02-01

There is a trend world-wide to grow crops in short rotation or in monoculture, particularly in conventional agriculture. This practice is becoming more prevalent due to a range of factors including economic market trends, technological advances, government incentives, and retailer and consumer demands. Land-use intensity will have to increase further in future in order to meet the demands of growing crops for both bioenergy and food production, and long rotations may not be considered viable or practical. However, evidence indicates that crops grown in short rotations or monoculture often suffer from yield decline compared to those grown in longer rotations or for the first time. Numerous factors have been hypothesised as contributing to yield decline, including biotic factors such as plant pathogens, deleterious rhizosphere microorganisms, mycorrhizas acting as pathogens, and allelopathy or autotoxicity of the crop, as well as abiotic factors such as land management practices and nutrient availability. In many cases, soil microorganisms have been implicated either directly or indirectly in yield decline. Although individual factors may be responsible for yield decline in some cases, it is more likely that combinations of factors interact to cause the problem. However, evidence confirming the precise role of these various factors is often lacking in field studies due to the complex nature of cropping systems and the numerous interactions that take place within them. Despite long-term knowledge of the yield-decline phenomenon, there are few tools to counteract it apart from reverting to longer crop rotations or break crops. Alternative cropping and management practices such as double-cropping or inter-cropping, tillage and organic amendments may prove valuable for combating some of the negative effects seen when crops are grown in short rotation. Plant breeding continues to be important, although this does require a specific breeding target to be identified. This

ARBRE monitoring - ecology of short rotation coppice plantations. Interim report 2000

Energy Technology Data Exchange (ETDEWEB)

Rich, T.J.; Sage, R.; Moore, N.; Robertson, P.; Aegerter, J.; Bishop, J.

2001-07-01

Short Rotation willow coppice (SRC) is a potential habitat for wildlife in the British countryside according to research reported in the late 1990s, but so far the trials have been on small plantations without reference to the land use it would supersede. This interim report, on a 4-year study which began in January 2000, discusses the commercial availability of SRC plantations and assesses what might be achievable by changing land usage. Work so far, conducted on indicator species (songbirds, ground flora, butterflies, insects), suggests that there are likely to be marked environmental benefits to be gained through SRC.

Free-air CO2 enrichment (FACE) enhances biomass production in a short-rotation poplar plantation

NARCIS (Netherlands)

Calfapietra, C.; Gielen, B.; Galema, A.N.J.; Lukac, M.; Angelis, de P.; Moscatelli, M.C.; Ceulemans, R.; Scarascia-Mugnozza, G.

2003-01-01

This paper investigates the possible contribution of Short Rotation Cultures (SRC) to carbon sequestration in both current and elevated atmospheric CO2 concentrations ([CO2]). A dense poplar plantation (1 x 1 m) was exposed to a [CO2] of 550 ppm in Central Italy using the free-air CO2 enrichment

Thermochemical and physical evaluation of poplar genotypes as short rotation forestry crops for energy use

International Nuclear Information System (INIS)

Monedero, Esperanza; Hernández, Juan José; Cañellas, Isabel; Otero, Jose María; Sixto, Hortensia

2016-01-01

Highlights: • The combustion properties of poplar genotypes harvested from three different sites were analyzed. • Both the genotype and the locations affect the expected combustion behavior. • Among the poplar genotypes, ‘Monviso’ and ‘Viriato’ are expected to have better combustion behavior. • No operating problems derived from fouling/corrosion are expected for any of the genotypes. - Abstract: Short rotation plantations of fast-growing species provide a promising way to produce heat and electricity from renewable sources. The thermo-chemical and physical properties of different genotypes of poplar in short rotation forestry crops grown at three locations with different climatic and edaphic characteristics as well as planting density, have been determined in order to characterize the most appropriate biomass in terms of energy potential. The planting density was 6666 or 13,333 trees/ha (depending on the location) in a rotation of three-four years and the analysis was carried out at the end of the first rotation. For all the genotypes, experimental tests to quantify the moisture content, particle size distribution, bulk density, heating value, ash content and composition as well as the volatile matter were performed. In addition, natural air drying of biomass (stem and branches) was studied in two locations with the aim of determining the humidity loss during raw storage. A significant effect of the genotype and the planting density on the biomass properties was observed. The results obtained indicate that ‘Monviso’ and ‘Viriato’ are the most suitable genotypes. No operational problems related to ash fouling and deposition in combustion devices are expected for any of the genotypes studied.

Field performance of Populus in short-rotation intensive culture plantations in the north-central U.S.

Science.gov (United States)

Edward A. Hansen; Michael E. Ostry; Wendell D. Johnson; David N. Tolsted; Daniel A. Netzer; William E. Berguson; Richard B. Hall

1994-01-01

Describes a network of short-rotation, Populus research and demonstration plantations that has been established across a 5-state region in the north-central U.S. to identify suitable hybrid poplar clones for large-scale biomass plantations in the region. Reports 6-year results.

Background CH4 and N2O fluxes in low-input short rotation coppice

Science.gov (United States)

Görres, Carolyn-Monika; Zenone, Terenzio; Ceulemans, Reinhart

2016-04-01

Extensively managed short rotation coppice systems are characterized by low fluxes of CH4 and N2O. However due to the large global warming potential of these trace gases (GWP100: CH4: 34, N2O: 298), such background fluxes can still significantly contribute to offsetting the CO2 uptake of short rotation coppice systems. Recent technological advances in fast-response CH4 and N2O analysers have improved our capability to capture these background fluxes, but their quantification still remains a challenge. As an example, we present here CH4 and N2O fluxes from a short-rotation bioenergy plantation in Belgium. Poplars have been planted in a double-row system on a loamy sand in 2010 and coppiced in the beginning of 2012 and 2014 (two-year rotation system). In 2013 (June - November) and 2014 (April - August), the plantation's CH4 and N2O fluxes were measured in parallel with an eddy covariance tower (EC) and an automated chamber system (AC). The EC had a detection limit of 13.68 and 0.76 μmol m-2 h-1 for CH4 and N2O, respectively. The median detection limit of the AC was 0.38 and 0.08 μmol m-2 h-1 for CH4 and N2O, respectively. The EC picked up a few high CH4 emission events with daily averages >100 μmol m-2 h-1, but a large proportion of the measured fluxes were within the EC's detection limit. The same was true for the EC-derived N2O fluxes where the daily average flux was often close to the detection limit. Sporadically, some negative (uptake) fluxes of N2O were observed. On the basis of the EC data, no clear link was found between CH4 and N2O fluxes and environmental variables. The problem with fluxes within the EC detection limit is that a significant amount of the values can show the opposite sign, thus "mirroring" the true flux. Subsequently, environmental controls of background trace gas fluxes might be disguised in the analysis. As a next step, it will be tested if potential environmental drivers of background CH4 and N2O fluxes at the plantation can be

Biomass yield potential of short-rotation hardwoods in the Great Plains

Energy Technology Data Exchange (ETDEWEB)

Geyer, W A [Kansas State Univ., Manhattan, KS (USA). Dept. of Forestry

1989-01-01

Wood for fuel has increased in importance. Its primary use in the world is for energy, increasingly coming from wood wastes and new biomass sources. One solution to the potential problem of using high-quality trees for fuel could be woody biomass grown under a short-rotation intensive culture system. Species, size, age and spacing are factors that affect biomass production of broadleafed trees. Trials of several species grown at close spacing (0.3 m x 0.3 m) and cut at various ages are described and related to the growth and yield of more conventionally spaced plantings on an alluvial site in eastern Kansas. (author).

Impact of elevated CO2 and nitrogen fertilization on foliar elemental composition in a short rotation poplar plantation

International Nuclear Information System (INIS)

Marinari, Sara; Calfapietra, Carlo; De Angelis, Paolo; Mugnozza, Giuseppe Scarascia; Grego, Stefano

2007-01-01

The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO 2 and fertilization (two CO 2 treatments, elevated CO 2 and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO 2 enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO 2 and N fertilization amplified some element unbalances such as the K/N-ratio. - CO 2 enrichment reduced foliar nitrogen and increased the magnesium concentration in poplar

Short-rotation woody-crops program. Quarterly progress report for period ending August 31, 1981

Energy Technology Data Exchange (ETDEWEB)

Cushman, J.H.; Ranney, J.W.

1982-04-01

Progress of twenty-one projects in the Short Rotation Woody Crops Program is summarized for the period June 1 through August 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major program activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

Short-rotation woody-crops program. Quarterly progress report for period ending May 31, 1981

Energy Technology Data Exchange (ETDEWEB)

Cushman, J.H.; Ranney, J.W.

1982-04-01

Progress of twenty projects in the Short Rotation Woody Crops Program is summarized for the period March 1 through May 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major project activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

Greenhouse gas mitigation potential of short-rotation-coppice based generation of electricity in Germany

Energy Technology Data Exchange (ETDEWEB)

Hansen, A.; Meyer-Aurich, A.; Kern, J.; Balasus, A.; Prochnow, A. [Leibniz Inst. of Agricultural Engineering, Potsdam (Germany)

2010-07-01

The generation of energy from wood biomass may help secure local energy supplies and reduce the greenhouse effect by substituting fossil resources with bio-based ones. In the case of short rotation coppice (SRC), bio-based resources can be generated by extensive agricultural production systems. They produce less carbon dioxide equivalent (CO{sub 2eq}) emissions than fossil resources. This paper reported on a study in which a model system was developed for a regional supply chain producing second generation bioenergy generated from SRC in eastern Germany. The study focuses on the generation of electricity and was compared to a business-as-usual reference system, based on the latest CO{sub 2} mitigation factors for renewable energies in the German power-generation mix. A life cycle assessment based on greenhouse gas (GHG) inventories was also conducted in which other factors were also considered, such as options for nutrient cycling. The key determinants for GHG mitigation with SRC were also discussed with regards to indirect land-use effects resulting from increased demand for land.

Sensitivity of short rotation poplar coppice biomass productivity to the throughfall reduction Estimating future drought impacts

Czech Academy of Sciences Publication Activity Database

Orság, Matěj; Fischer, Milan; Tripathi, Abishek; Žalud, Zdeněk; Trnka, Miroslav

2018-01-01

Roč. 109 (2018), s. 182-189 ISSN 0961-9534 Institutional support: RVO:86652079 Keywords : water -use * energy * stand * systems * dominance * density * l. * Dominance * Drought * Mortality * Productivity * Short-rotation coppice * Throughfall manipulation Subject RIV: GC - Agronomy OBOR OECD: Agronomy, plant breeding and plant protection Impact factor: 3.219, year: 2016

Reduced critical rotation for resistive-wall mode stabilization in a near-axisymmetric configuration.

Science.gov (United States)

Reimerdes, H; Garofalo, A M; Jackson, G L; Okabayashi, M; Strait, E J; Chu, M S; In, Y; La Haye, R J; Lanctot, M J; Liu, Y Q; Navratil, G A; Solomon, W M; Takahashi, H; Groebner, R J

2007-02-02

Recent DIII-D experiments with reduced neutral beam torque and minimum nonaxisymmetric perturbations of the magnetic field show a significant reduction of the toroidal plasma rotation required for the stabilization of the resistive-wall mode (RWM) below the threshold values observed in experiments that apply nonaxisymmetric magnetic fields to slow the plasma rotation. A toroidal rotation frequency of less than 10 krad/s at the q=2 surface (measured with charge exchange recombination spectroscopy using C VI) corresponding to 0.3% of the inverse of the toroidal Alfvén time is sufficient to sustain the plasma pressure above the ideal MHD no-wall stability limit. The low-rotation threshold is found to be consistent with predictions by a kinetic model of RWM damping.

Designing safer composite helmets to reduce rotational accelerations during oblique impacts.

Science.gov (United States)

Mosleh, Yasmine; Cajka, Martin; Depreitere, Bart; Vander Sloten, Jos; Ivens, Jan

2018-05-01

Oblique impact is the most common accident situation that occupants in traffic accidents or athletes in professional sports experience. During oblique impact, the human head is subjected to a combination of linear and rotational accelerations. Rotational movement is known to be responsible for traumatic brain injuries. In this article, composite foam with a column/matrix composite configuration is proposed for head protection applications to replace single-layer uniform foam, to better attenuate rotational movement of the head during oblique impacts. The ability of composite foam in the mitigation of rotational head movement is studied by performing finite element (FE) simulations of oblique impact on flat and helmet shape specimens. The performance of composite foam with respect to parameters such as compliance of the matrix foam and the number, size and cross-sectional shape of the foam columns is explored in detail, and subsequently an optimized structure is proposed. The simulation results show that using composite foam instead of single-layer foam, the rotational acceleration and velocity of the headform can be significantly reduced. The parametric study indicates that using a more compliant matrix foam and by increasing the number of columns in the composite foam configuration, the rotation can be further mitigated. This was confirmed by experimental results. The simulation results were also analyzed based on global head injury criteria such as head injury criterion, rotational injury criterion, brain injury criterion and generalized acceleration model for brain injury threshold which further confirmed the superior performance of composite foam versus single-layer homogeneous expanded polystyrene foam. The findings of simulations give invaluable information for design of protective helmets or, for instance, headliners for the automotive industry.

Enhancing the conservation value of short rotation biomass coppice. Phase 1

International Nuclear Information System (INIS)

Sage, R.B.; Robertson, P.A.; Poulson, J.G.

1994-01-01

The game and conservation value of existing short rotation coppice plantations in Britain and Ireland has been assessed. Four main wild life groups were surveyed during appropriate periods in 1993. These were songbirds, butterflies, pheasants and ground flora. For each group the process of field data collection, analysis and interpretation is described, the results are summarized and briefly discussed. A final overall discussion of the results in terms of their general findings and how typical they may be for future, large-scale production plots is presented. Proposals are made regarding management techniques that could be used with future plantings to benefit the various wildlife groups. (50 figures, 19 tables, 30 references). (UK)

A further evaluation of herbicides for post-emergence use in short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D.J.

2002-07-01

This report summarises the findings of a project evaluating the safety and efficiency of eleven herbicides for controlling weeds in newly plated willow short rotation coppices, and provides growers with information on post-emergence herbicide options, control of problem weeds, and emergency treatments. Weed germination, crop safety, and the encouraging results obtained using Reflex T and Impuls are discussed. It is suggested that a Technical Register of herbicide applications with contributions by growers and advisers should be considered by the British Biogen trade industry body.

Profitability potential for Pinus taeda L. (loblolly pine) short-rotation bioenergy plantings in the southern USA

Science.gov (United States)

James H. Perdue; John A. Stanturf; Timothy M. Young; Xia Huang; Derek Dougherty; Michael Pigott; Zhimei Guo

2017-01-01

The use of renewable resources is important to the developing bioenergy economy and short rotation woody crops (SRWC) are key renewable feedstocks. A necessary step in advancing SRWC is defining regions suitable for SRWC commercial activities and assessing the relative economic viability among suitable regions. The goal of this study was to assess the potential...

Sensitivity of short rotation poplar coppice biomass productivity to the throughfall reduction – Estimating future drought impacts

Czech Academy of Sciences Publication Activity Database

Orság, Matěj; Fischer, Milan; Tripathi, Abishek; Žalud, Zdeněk; Trnka, Miroslav

2018-01-01

Roč. 109 (2018), s. 182-189 ISSN 0961-9534 R&D Projects: GA MŠk(CZ) LO1415; GA MZe(CZ) QJ1610072 Institutional support: RVO:86652079 Keywords : Dominance * Drought * Mortality * Productivity * Short-rotation coppice * Throughfall manipulation Subject RIV: GC - Agronomy Impact factor: 3.219, year: 2016

An identification of potential new herbicides for short rotation coppice (Task 4). Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This report summarises the findings of a project to identify potential new herbicides and their suitability for weed control in commercial short rotation coppice (SRC) crops, and to establish the safety of the crops. The arrangements for the use of 'off-label' pesticides, which are permitted for use on other crops, on SRC are discussed along with the importance of the use of laboratory pot trials and field trials. Several herbicides are proposed for larger scale field trials.

Measuring and partitioning soil respiration in sharkey shrink-swell clays under plantation grown short-rotation woody crops

Science.gov (United States)

Wilson G. Hood; Michael C. Tyree; Dylan N. Dillaway Dillaway; Theodor D. Leininger

2015-01-01

The Lower Mississippi Alluvial Valley (LMAV) offers an ecological niche for short-rotation woody crop (SRWC) production by mating marginal agricultural land with optimal growing conditions. Approximately 1.7 million ha within the LMAV consist of Sharkey shrink-swell clays. They are considered marginal in terms of traditional agricultural productivity due to their...

Soil carbon, after 3 years, under short-rotation woody crops grown under varying nutrient and water availability

Science.gov (United States)

Felipe G. Sanchez; Mark Coleman; Charles T. Garten; Robert J. Luxmoore; John A. Stanturf; Carl Trettin; Stan D. Wullschleger

2007-01-01

Soil carbon contents were measured on a short-rotation woody crop study located on the US Department of Energy's Savannah River Site outside Aiken, SC. This study included fertilization and irrigation treatments on five tree genotypes (sweetgum, loblolly pine, sycamore and two eastern cottonwood clones). Prior to study installation, the previous pine stand was...

Economic impacts of short-rotation woody crops for energy or oriented strand board: a Minnesota case study

Science.gov (United States)

William F. Lazarus; Douglas G. Tiffany; Ronald S. Zalesny Jr.; Don E. Riemenschneider

2011-01-01

Short-rotation woody crops (SRWC) such as hybrid poplars are becoming increasingly competitive with agriculture on marginal land. The trees can be grown for energy and for traditional uses such as oriented strandboard. Using IMPLAN (Impact Analysis for Planning) software, we modeled the impacts of shifting land use from hay and pasture for cow-calf beef operations to...

Rotator Cuff Strength Ratio and Injury in Glovebox Workers

Energy Technology Data Exchange (ETDEWEB)

Weaver, Amelia M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-01-30

Rotator cuff integrity is critical to shoulder health. Due to the high workload imposed upon the shoulder while working in an industrial glovebox, this study investigated the strength ratio of the rotator cuff muscles in glovebox workers and compared this ratio to the healthy norm. Descriptive statistics were collected using a short questionnaire. Handheld dynamometry was used to quantify the ratio of forces produced in the motions of shoulder internal and external rotation. Results showed this population to have shoulder strength ratios that were significantly different from the healthy norm. The deviation from the normal ratio demonstrates the need for solutions designed to reduce the workload on the rotator cuff musculature of glovebox workers in order to improve health and safety. Assessment of strength ratios can be used to screen for risk of symptom development.

A study of human performance in a rotating environment

Science.gov (United States)

Green, J. A.; Peacock, J. L.; Holm, A. P.

1971-01-01

Consideration is given to the lack of sufficient data relative to the response of man to the attendant oculovestibular stimulations induced by multi-directional movement of an individual within the rotating environment to provide the required design criteria. This was done to determine the overall impact of artificial gravity simulations on potential design configurations and crew operational procedures. Gross locomotion and fine motor performance were evaluated. Results indicate that crew orientation, rotational rates, vehicle design configurations, and operational procedures may be used to reduce the severity of the adverse effects of the Coriolis and cross-coupled angular accelerations acting on masses moving within a rotating environment. Results further indicate that crew selection, motivation, and short-term exposures to the rotating environment may be important considerations for future crew indoctrination and training programs.

Greenhouse gas emissions from short-rotation forestry on a drained and rewetted fen

Science.gov (United States)

Schlaipfer, Martina; Fuertes Sánchez, Alicia; Drösler, Matthias

2017-04-01

More than 95 % of German peatlands have been drained, primarily for agricultural and forestry use. They constitute a significant source of greenhouse gases (GHG) with emissions of approximately 47 million tons per year. Propelled by the German energy turnaround farmers have increasingly converted their cropland to short rotation forestry (SRF), amongst them some who are cultivating drained peatland. In this study GHG emissions from alder and poplar short rotation plantations with differing groundwater levels near Rosenheim, Bavaria, were monitored over the course of three-and-a-half years. Moreover, the effect of ploughing for SRF establishment was investigated as well. Understorey GHG fluxes were measured using closed-chamber approaches. Gas samples were enclosed in vials every second week and analysed for their CH4 and N2O concentrations by gas chromatography at a laboratory. On-site measurements of CO2 fluxes were carried out over the course of a day every three to four weeks with a dynamic closed-chamber technique. Allometric methods were employed to estimate carbon sequestration into trees. Sheet piling was installed around a set of measurement sites in December 2014 to accentuate the difference between the sites with high and low water tables. As a result the water level around those sites rose from an average of -36.1 ± 6.1 cm in 2013 and 2014 to -20.8 ± 3.7 cm in 2015. The water table outside the sheet piling showed values of -61.8 ± 5.7 cm and -72.1 ± 6.2 cm in those years, respectively. First results suggest a limited effect of ploughing for SRF establishment on understorey GHG emissions. However, there seems to be a distinct impact on tree productivity. CO2 fluxes in the understorey seem to be strongly influenced by water table, but also land management (mulching of understorey vegetation to reduce weed competition for trees during the first year and for pest control in subsequent years) and shading of the understorey vegetation by trees. There is a

Short rotation woody crops: Using agroforestry technology for energy in the United States

International Nuclear Information System (INIS)

Wright, L.L.; Ranney, J.W.

1991-01-01

Agroforestry in the United States is being primarily defined as the process of using trees in agricultural systems for conservation purposes and multiple products. The type of agroforestry most commonly practiced in many parts of the world, that is the planting of tree crops in combination with food crops or pasture, is the type least commonly practiced in the United States. One type of agroforestry technique, which is beginning now and anticipated to expand to several million acres in the United States, is the planting of short-rotation woody crops (SRWCs) primarily to provide fiber and fuel. Research on SRWC's and environmental concerns are described

Results from software based empirical models of and standing biomass for poplar and willow grown as short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Baldwin, M.E.; Morgan, G.W.; Brewer, A.C. (Forest Research Biometrics, Surveys and Statistics Division, Forest Research, Wrecclesham (United Kingdom))

2007-07-01

Statistical analysis was used to create a model for estimating the quantity of biomass produced by crops of poplar and willow grown as short rotation coppice. This model was converted into a software system as described here. The software is currently available for scientific demonstration. (orig.)

Simvastatin reduces fibrosis and protects against muscle weakness after massive rotator cuff tear.

Science.gov (United States)

Davis, Max E; Korn, Michael A; Gumucio, Jonathan P; Harning, Julie A; Saripalli, Anjali L; Bedi, Asheesh; Mendias, Christopher L

2015-02-01

Chronic rotator cuff tears are a common source of shoulder pain and disability, and patients with chronic cuff tears often have substantial weakness, fibrosis, inflammation, and fat accumulation. Identifying therapies to prevent the development of these pathologic processes will likely have a positive impact on clinical outcomes. Simvastatin is a drug with demonstrated anti-inflammatory and antifibrotic effects in many tissues but had not previously been studied in the context of rotator cuff tears. We hypothesized that after the induction of a massive supraspinatus tear, simvastatin would protect muscles from a loss of force production and fibrosis. We measured changes in muscle fiber contractility, histology, and biochemical markers of fibrosis and fatty infiltration in rats that received a full-thickness supraspinatus tear and were treated with either carrier alone or simvastatin. Compared with vehicle-treated controls, simvastatin did not have an appreciable effect on muscle fiber size, but treatment did increase muscle fiber specific force by 20%. Simvastatin also reduced collagen accumulation by 50% but did not affect triglyceride content of muscles. Several favorable changes in the expression of genes and other markers of inflammation, fibrosis, and regeneration were also observed. Simvastatin partially protected muscles from the weakness that occurs as a result of chronic rotator cuff tear. Fibrosis was also markedly reduced in simvastatin-treated animals. Whereas further studies are necessary, statin medication could potentially help improve outcomes for patients with rotator cuff tears. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Structural Characteristics of Rotate Vector Reducer Free Vibration

Directory of Open Access Journals (Sweden)

Chuan Chen

2017-01-01

Full Text Available For RV reducer widely used in robots, vibration significantly affects its performance. A lumped parameter model is developed to investigate free vibration characteristics without and with gyroscopic effects. The dynamic model considers key factors affecting vibration such as involute and cycloid gear mesh stiffness, crankshaft bending stiffness, and bearing stiffness. For both nongyroscopic and gyroscopic systems, free vibrations are examined and compared with each other. Results reveal the specific structure of vibration modes for both systems, which results from symmetry structure of RV reducer. According to vibration of the central components, vibration modes of two systems can be classified into three types, rotational, translational, and planetary component modes. Different from nongyroscopic system, the eigenvalues with gyroscopic effects are complex-valued and speed-dependent. The eigenvalue for a range of carrier speeds is obtained by numerical simulation. Divergence and flutter instability is observed at speeds adjacent to critical speeds. Furthermore, the work studies effects of key factors, which include crankshaft eccentricity and the number of pins, on eigenvalues. Finally, experiment is performed to verify the effectiveness of the dynamic model. The research of this paper is helpful for the analysis on free vibration and dynamic design of RV reducer.

Numerical Analysis of Rotating Pumping Flows in Inter-Coil Rotor Cavities and Short Cooling Grooves of a Generator

Directory of Open Access Journals (Sweden)

Wei Tong

2001-01-01

Full Text Available An important characteristic of wall rotating-driven flows is the tendency of fluid with high angular momentum to be flung radially outward. For a generator, the rotor rotating-driven flow, usually referred to as the rotating pumping flow, plays an important role in rotor winding cooling. In this study, three-dimensional numerical analyzes are presented for turbulent pumping flow in the inter-coil rotor cavity and short cooling grooves of a generator. Calculations of the flow field and the mass flux distribution through the grooves were carried out in a sequence of four related cases Under an isothermal condition: (a pumping flow, which is the self-generated flow resulted from the rotor pumping action; (b mixing flow, which is the combination of the ventilating flow and pumping flow, under a constant density condition; (c mixing flow, with density modeled by the ideal gas law; and (d mixing flow, with different pressure differentials applied on the system. The comparisons of the results from these cases can provide useful information regarding the impacts of the ventilating flow, gas density, and system pressure differential on the mass flux distribution in the short cooling grooves. Results show that the pumping effect is strong enough to generate the cooling flow for rotor winding cooling. Therefore, for small- or mid-size generators ventilation fans may be eliminated. It also suggests that increasing the chimney dimension can improve the distribution uniformity of mass flux through the cooling grooves.

Establishment and monitoring of large scale trials of short rotation coppice for energy

Energy Technology Data Exchange (ETDEWEB)

Mitchell, C.; Stevens, E.A.; Watters, M.P.

1998-09-01

The overall objective of the trials was to obtain information on costs, logistics, productivity and biology of short rotation coppice crops in order to evaluate their potential for producing wood for fuel. More specifically, the objectives of the final and most recent phase of the research work were: the continuing management and monitoring of the coppice trial sites established during phases 1 and 2 of the project; to provide technical and economic data on the management and maintenance of the continuing coppice trail sites; to identify appropriate methods for stool removal and land reclamation and provide technical and economic data on those operations; and to undertake yield assessment at the remaining sites using appropriate methods of yield estimation. (author)

Assessment of soil nitrogen and phosphorous availability under elevated CO2 and N-fertilization in a short rotation poplar plantation

NARCIS (Netherlands)

Lagomarsino, A.; Moscatelli, M.C.; Hoosbeek, M.R.; Angelis, de P.; Grego, S.

2008-01-01

Photosynthetic stimulation by elevated [CO2] is largely regulated by nitrogen and phosphorus availability in the soil. During a 6 year Free Air CO2 Enrichment (FACE) experiment with poplar trees in two short rotations, inorganic forms of soil nitrogen, extractable phosphorus, microbial and total

Mental rotation impairs attention shifting and short-term memory encoding: neurophysiological evidence against the response-selection bottleneck model of dual-task performance.

Science.gov (United States)

Pannebakker, Merel M; Jolicœur, Pierre; van Dam, Wessel O; Band, Guido P H; Ridderinkhof, K Richard; Hommel, Bernhard

2011-09-01

Dual tasks and their associated delays have often been used to examine the boundaries of processing in the brain. We used the dual-task procedure and recorded event-related potentials (ERPs) to investigate how mental rotation of a first stimulus (S1) influences the shifting of visual-spatial attention to a second stimulus (S2). Visual-spatial attention was monitored by using the N2pc component of the ERP. In addition, we examined the sustained posterior contralateral negativity (SPCN) believed to index the retention of information in visual short-term memory. We found modulations of both the N2pc and the SPCN, suggesting that engaging mechanisms of mental rotation impairs the deployment of visual-spatial attention and delays the passage of a representation of S2 into visual short-term memory. Both results suggest interactions between mental rotation and visual-spatial attention in capacity-limited processing mechanisms indicating that response selection is not pivotal in dual-task delays and all three processes are likely to share a common resource like executive control. Copyright © 2011 Elsevier Ltd. All rights reserved.

Short revolving wings enable hovering animals to avoid stall and reduce drag

Science.gov (United States)

Lentink, David; Kruyt, Jan W.; Heijst, Gertjan F.; Altshuler, Douglas L.

2014-11-01

Long and slender wings reduce the drag of airplanes, helicopters, and gliding animals, which operate at low angle of attack (incidence). Remarkably, there is no evidence for such influence of wing aspect ratio on the energetics of hovering animals that operate their wings at much higher incidence. High incidence causes aircraft wings to stall, hovering animals avoid stall by generating an attached vortex along the leading edge of their wings that elevates lift. Hypotheses that explain this capability include the necessity for a short radial distance between the shoulder joint and wing tip, measured in chord lengths, instead of the long tip-to-tip distance that elevates aircraft performance. This stems from how hovering animals revolve their wings around a joint, a condition for which the precise effect of aspect ratio on stall performance is unknown. Here we show that the attachment of the leading edge vortex is determined by wing aspect ratio with respect to the center of rotation-for a suite of aspect ratios that represent both animal and aircraft wings. The vortex remains attached when the local radius is shorter than 4 chord lengths, and separates outboard on more slender wings. Like most other hovering animals, hummingbirds have wing aspect ratios between 3 and 4, much stubbier than helicopters. Our results show this makes their wings robust against flow separation, which reduces drag below values obtained with more slender wings. This revises our understanding of how aspect ratio improves performance at low Reynolds numbers.

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

International Nuclear Information System (INIS)

Pacot, Olivier; Avellan, François; Kato, Chisachi

2014-01-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

Science.gov (United States)

Pacot, Olivier; Kato, Chisachi; Avellan, François

2014-03-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment.

Rotating machinery surveillance system reduces plant downtime and radiation exposure

International Nuclear Information System (INIS)

Bohanick, J.S.; Robinson, J.C.; Allen, J.W.

1988-01-01

A rotating machinery surveillance system (RMSS) was permanently installed at Grand Gulf nuclear station (GGNS) as part of a program sponsored by the US Department of Energy whose goal was to reduce radiation exposure to power plant personnel resulting from the inspection, maintenance, and repair of rotating machinery. The RMSS was installed at GGNS in 1983 to continuously monitor 173 analog vibration signals from proximity probes mounted on 26 machine trains and ∼450 process data points via a computer data link. Vibration frequency spectra, i.e., the vibration amplitude versus frequency of vibration, and various characterizations of these spectra are the fundamental data collected by the RMSS for performing machinery diagnostics. The RMSS collects vibration frequency spectra on a daily basis for all the monitored rotating equipment and automatically stores the collected spectra for review by the vibration engineer. Vibration spectra automatically stored by the RMSS fall into categories that include the last normal, alarm, minimum and maximum, past three-day data set, baseline, current, and user-saved spectra. During first and second fuel-cycle operation at GGNS, several significant vibration problems were detected by the RMSS. Two of these are presented in this paper: recirculation pumps and turbine-generator bearing degradation. The total reduction in personnel radiation exposure at GGNS from 1985 to 1987 due to the presence of the RMSS was estimated to be in the range from 49 to 54 person-rem

Biomass energy in organic farming - the potential role of short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Joergensen, Uffe; Dalgaard, Tommy [Danish Inst. of Agricultural Sciences (DIAS), Dept. of Agroecology, Research Centre Foulum, Tjele (Denmark); Kristensen, Erik Steen [Danish Research Centre for Organic Farming (DARCOF), Research Centre Foulum, Tjele (Denmark)

2005-02-01

One of the aims of organic farming is to 'reduce the use of non-renewable resources (e.g. fossil fuels) to a minimum'. So far, however, only very little progress has been made to introduce renewable energy in organic farming. This paper presents energy balances of Danish organic farming compared with energy balances of conventional farming. In general, the conversion to organic farming leads to a lower energy use (approximately 10% per unit of product). But the production of energy in organic farming is very low compared with the extensive utilisation of straw from conventional farming in Denmark (energy content of straw used for energy production was equivalent to 18% of total energy input in Danish agriculture in 1996). Biomass is a key energy carrier with a good potential for on-farm development. Apart from utilising farm manure and crop residues for biogas production, the production of nutrient efficient short rotation coppice (SRC) is an option in organic farming. Alder (Alnus spp.) is an interesting crop due to its symbiosis with the actinomycete Frankia, which has the ability to fix up to 185 kg/ha nitrogen (N{sub 2}) from the air. Yields obtained at different European sites are presented and the R and D needed to implement energy cropping in organic farming is discussed. Possible win-win solutions for SRC production in organic farming that may facilitate its implementation are; the protection of ground water quality in intensively farmed areas, utilisation of wastewater for irrigation, or combination with outdoor animal husbandry such as pigs or poultry. (Author)

Admixture of lime in connection with deep rotary cultivation for short rotation energy forest

Energy Technology Data Exchange (ETDEWEB)

Danfors, B; Stambeck, A; Aasberg, G

1985-01-01

Spaghnum soils, which could be used for production of short rotation energy forests (Salix), require lime for the adjustment of the pH-level to obtain production at acceptable levels. It is necessary that the lime is distributed uniformly in the soil profile to a depth of at least 40-50 cm. The investigation has studied three methods of spreading and incorporating lime in the uppermost layer of soil. The first method concerned ploughing of peat soil with a conventional agricultural plough, the second method concerned rotovation with an agricutural rotovator to maximally 20 cm depth. In both cases the lime has been spread with a centrifugal broadcaster before the soil tillage. The third method implied simultaneous spreading of the lime and rotovation of the peat to a depth of maximally 50 cm, JTI has built and constructed a machine for this purpose. Ploughing as the only method of soil tillage of peat soils before planting of short rotation energy forests is rejected for two reasons. 1. Certain peat soils which have such mechanical properties that they immediately completely clog a plough. 2. The deficient distribution of lime in the ploughed layer. Rotovation with an agricultural rotovator has been done with good results. The delivery of lime in connection with the rotovation works well provided that the lime is dry. The peat is efficiently disintegrated and the lime gets a sufficiently uniform admixture. The cultivation depth, 40-50 cm, appears to be sufficient for the Salix plants to cope with the water supply during the summer. Limitations which should be discussed concern the cost of such an intensive and deep tillage of the peat.

Activation of biceps femoris long head reduces tibiofemoral anterior shear force and tibial internal rotation torque in healthy subjects.

Science.gov (United States)

Azmi, Nur Liyana; Ding, Ziyun; Xu, Rui; Bull, Anthony M J

2018-01-01

The anterior cruciate ligament (ACL) provides resistance to tibial internal rotation torque and anterior shear at the knee. ACL deficiency results in knee instability. Optimisation of muscle contraction through functional electrical stimulation (FES) offers the prospect of mitigating the destabilising effects of ACL deficiency. The hypothesis of this study is that activation of the biceps femoris long head (BFLH) reduces the tibial internal rotation torque and the anterior shear force at the knee. Gait data of twelve healthy subjects were measured with and without the application of FES and taken as inputs to a computational musculoskeletal model. The model was used to investigate the optimum levels of BFLH activation during FES gait in reducing the anterior shear force to zero. This study found that FES significantly reduced the tibial internal rotation torque at the knee during the stance phase of gait (p = 0.0322) and the computational musculoskeletal modelling revealed that a mean BFLH activation of 20.8% (±8.4%) could reduce the anterior shear force to zero. At the time frame when the anterior shear force was zero, the internal rotation torque was reduced by 0.023 ± 0.0167 Nm/BW, with a mean 188% reduction across subjects (p = 0.0002). In conclusion, activation of the BFLH is able to reduce the tibial internal rotation torque and the anterior shear force at the knee in healthy control subjects. This should be tested on ACL deficient subject to consider its effect in mitigating instability due to ligament deficiency. In future clinical practice, activating the BFLH may be used to protect ACL reconstructions during post-operative rehabilitation, assist with residual instabilities post reconstruction, and reduce the need for ACL reconstruction surgery in some cases.

Effects of Successive Rotation Regimes on Carbon Stocks in Eucalyptus Plantations in Subtropical China Measured over a Full Rotation.

Science.gov (United States)

Li, Xiaoqiong; Ye, Duo; Liang, Hongwen; Zhu, Hongguang; Qin, Lin; Zhu, Yuling; Wen, Yuanguang

2015-01-01

Plantations play an important role in carbon sequestration and the global carbon cycle. However, there is a dilemma in that most plantations are managed on short rotations, and the carbon sequestration capacities of these short-rotation plantations remain understudied. Eucalyptus has been widely planted in the tropics and subtropics due to its rapid growth, high adaptability, and large economic return. Eucalyptus plantations are primarily planted in successive rotations with a short rotation length of 6~8 years. In order to estimate the carbon-stock potential of eucalyptus plantations over successive rotations, we chose a first rotation (FR) and a second rotation (SR) stand and monitored the carbon stock dynamics over a full rotation from 1998 to 2005. Our results showed that carbon stock in eucalyptus trees (TC) did not significantly differ between rotations, while understory vegetation (UC) and soil organic matter (SOC) stored less carbon in the SR (1.01 vs. 2.76 Mg.ha(-1) and 70.68 vs. 81.08 Mg. ha(-1), respectively) and forest floor carbon (FFC) conversely stored more (2.80 vs. 2.34 Mg. ha(-1)). The lower UC and SOC stocks in the SR stand resulted in 1.13 times lower overall ecosystem carbon stock. Mineral soils and overstory trees were the two dominant carbon pools in eucalyptus plantations, accounting for 73.77%~75.06% and 20.50%~22.39%, respectively, of the ecosystem carbon pool. However, the relative contribution (to the ecosystem pool) of FFC stocks increased 1.38 times and that of UC decreased 2.30 times in the SR versus FR stand. These carbon pool changes over successive rotations were attributed to intensive successive rotation regimes of eucalyptus plantations. Our eight year study suggests that for the sustainable development of short-rotation plantations, a sound silvicultural strategy is required to achieve the best combination of high wood yield and carbon stock potential.

Effects of Successive Rotation Regimes on Carbon Stocks in Eucalyptus Plantations in Subtropical China Measured over a Full Rotation.

Directory of Open Access Journals (Sweden)

Xiaoqiong Li

Full Text Available Plantations play an important role in carbon sequestration and the global carbon cycle. However, there is a dilemma in that most plantations are managed on short rotations, and the carbon sequestration capacities of these short-rotation plantations remain understudied. Eucalyptus has been widely planted in the tropics and subtropics due to its rapid growth, high adaptability, and large economic return. Eucalyptus plantations are primarily planted in successive rotations with a short rotation length of 6~8 years. In order to estimate the carbon-stock potential of eucalyptus plantations over successive rotations, we chose a first rotation (FR and a second rotation (SR stand and monitored the carbon stock dynamics over a full rotation from 1998 to 2005. Our results showed that carbon stock in eucalyptus trees (TC did not significantly differ between rotations, while understory vegetation (UC and soil organic matter (SOC stored less carbon in the SR (1.01 vs. 2.76 Mg.ha(-1 and 70.68 vs. 81.08 Mg. ha(-1, respectively and forest floor carbon (FFC conversely stored more (2.80 vs. 2.34 Mg. ha(-1. The lower UC and SOC stocks in the SR stand resulted in 1.13 times lower overall ecosystem carbon stock. Mineral soils and overstory trees were the two dominant carbon pools in eucalyptus plantations, accounting for 73.77%~75.06% and 20.50%~22.39%, respectively, of the ecosystem carbon pool. However, the relative contribution (to the ecosystem pool of FFC stocks increased 1.38 times and that of UC decreased 2.30 times in the SR versus FR stand. These carbon pool changes over successive rotations were attributed to intensive successive rotation regimes of eucalyptus plantations. Our eight year study suggests that for the sustainable development of short-rotation plantations, a sound silvicultural strategy is required to achieve the best combination of high wood yield and carbon stock potential.

Potential of poplar short rotation coppice cultivation for bioenergy in Southern Portugal

International Nuclear Information System (INIS)

Pereira, Sandrina; Costa, Mário; Graça Carvalho, Maria da; Rodrigues, Abel

2016-01-01

Highlights: • Evaluation of the potential of poplar coppice cultivation for bioenergy. • Biomass costs from 76.9 to 120.5 Euro/ton and net energy from 34.7 to 75.4 PJ. • Biomass co-firing in power plants reduces CO_2 emissions between 8.2% and 16.5%. • A scenario of CO_2 allowances trading can turn the project financially viable. - Abstract: This manuscript examines the potential of poplar short rotation coppice cultivation for bioenergy in the Alentejo region, Southern Portugal. The biomass is intended to fulfil, at least, 10% (energy basis) of the fuel needs of two Portuguese coal-fired power plants (Sines and Pego), using co-firing technology. The study considers the overall production chain from cradle to power plant gate, cultivated in scrubland areas with duration of 12 years, harvested every three years and with 6667 plants per ha, covering a land area of about 52,250 ha. Three different biomass annual yields are assumed. The results show that the biomass selling prices range from 76.9 to 120.5 Euro ton"−"1, to match the production costs. The net energy of the overall project ranges from 34.7 to 75.4 PJ and the project cost from 619 to 823.9 MEuro. The main environmental impact of the project is the reduction of the CO_2 emissions due to the biomass co-firing, instead of burning coal alone. The power plants can reduce CO_2 emissions over the project lifetime between 8.2% and 16.5% of the current values. The financial analysis demonstrates that the project is not financially feasible without external grants, but a policy scenario of carbon allowances trading may be instrumental on turning it financially feasible, depending on allowances and coal market prices. Finally, with a reduction of 50% in the main costs, the project becomes financially feasible under a CO_2 emissions trading scenario for a biomass yield of 20 dry ton ha"−"1 per year.

Input-output analysis of energy requirements for short rotation, intensive culture, woody biomass

International Nuclear Information System (INIS)

Strauss, C.H.; Grado, S.C.

1992-01-01

A production model for short rotation, intensive culture (SRIC) plantations was developed to determine the energy and financial cost of woody biomass. The model was based on hybrid poplars planted on good quality agricultural sites at a density of 2100 cuttings ha -1 , with average annual growth forecast at 16 metric tonne, oven dry (mg(OD)). Energy and financial analyses showed preharvest cost 4381 megajoules (MJ) Mg -1 (OD) and $16 (US) Mg -1 (OD). Harvesting and transportation requirements increased the total costs 6130 MJ Mg -1 (OD) and $39 Mg -1 (OD) for the delivered material. On an energy cost basis, the principal input was land, whereas on a financial basis, costs were more uniformly distributed among equipment, land, labor, and materials and fuel

Short Rotation Crops in the United States

Energy Technology Data Exchange (ETDEWEB)

Wright, L L

1998-06-04

The report is based primarily on the results of survey questions sent to approximately 60 woody and 20 herbaceous crop researchers in the United States and on information from the U.S. Department of Energy's Bioenergy Feedstock Development Program. Responses were received from 13 individuals involved in woody crops research or industrial commercialization (with 5 of the responses coming from industry). Responses were received from 11 individuals involved in herbaceous crop research. Opinions on market incentives, technical and non-technical barriers, and highest priority research and development areas are summarized in the text. Details on research activities of the survey responders are provided as appendices to the paper. Woody crops grown as single-stem systems (primarily Populus and Eucalyptus species) are perceived to have strong pulp fiber and oriented strand board markets, and the survey responders anticipated that energy will comprise 25% or less of the utilization of single-stem short-rotation woody crops between now and 2010. The only exception was a response from California where a substantial biomass energy market does currently exist. Willows (Salix species) are only being developed for energy and only in one part of the United States at present. Responses from herbaceous crop researchers suggested frustration that markets (including biomass energy markets) do not currently exist for the crop, and it was the perception of many that federal incentives will be needed to create such markets. In all crops, responses indicate that a wide variety of research and development activities are needed to enhance the yields and profitability of the crops. Ongoing research activities funded by the U.S. Department of Energy's Bioenergy Feedstock Development Program are described in an appendix to the paper.

Annual and Intra-Annual Water Balance Components of a Short Rotation Poplar Coppice Based on Sap Flow and Micrometeorological and Hydrological Approaches

Czech Academy of Sciences Publication Activity Database

Fischer, Milan; Orság, Matěj; Trnka, Miroslav; Pohanková, Eva; Hlavinka, Petr; Tripathi, Abishek; Žalud, Zdeněk

2013-01-01

Roč. 991, JUN 04-07 (2013), s. 401-408 ISSN 0567-7572 Institutional support: RVO:67179843 Keywords : short rotation poplar coppice * water balance * sap flow * Bowen ratio and energy balance method * modeling Subject RIV: EH - Ecology, Behaviour

[Dual insertion paths design characteristics and short-term clinical observation of rotational path removable partial dentures].

Science.gov (United States)

Li, Jian; Jiang, Ting; Li, Sai; Chen, Wei

2013-02-18

To investigate design methods of dual insertion paths and observe a short-term clinic overview of rotational path removable partial dentures (RPDs). In the study, 40 patients with partial edentulous arches were included and divided into two groups. The patients in group one were restored with rotational path RPDs (10 Kennedy class III and 10 Kennedy class IV respectively). The patients in group two (20 patients), whose edentulous area was matched with the patients' in group one, were restored with the linear path RPDs. After surveying and simulative preparation on diagnostic casts, the basic laws of designing rotational path RPDs were summarized. The oral preparation was accurately performed under the guidance of indices made on diagnostic casts after simulative preparation. The 40 dentures were recalled two weeks and one year after the insertion. The evaluations of the clinic outcome, including retention, stability, mastication function, esthetics and wearing convenience, were marked out as good, acceptable, and poor. The comparison of the evaluation results was performed between the two groups. In the rotational path design for Kennedy class III or IV RPDs, the angles (α) of dual insertion paths should be designed within a scope, approximate 10°-15°.When the angle (α) became larger, the denture retention turned to be better, but accordingly the posterior abutments needed more preparation. In the clinical application, the first insertions of the 40 dentures were all favorably accomplished. When the rotational path RPDs were compared to linear path RPDs, the time consuming on first insertion had no statistical difference[(32±8) min and (33±8) min respectively, P>0.05]. Recalled two weeks and one year after the insertion, in the esthetics evaluation, 20 rotational path RPDs were all evaluated as "A", but only 7(two weeks after) and 6 (one year after) linear path RPDs were evaluated as "A"(P<0.05). There was no significant difference in other evaluation results

Coppicing evaluation of short rotation coppice in the southeast of the U.S. to determine appropriate harvesting methods.

Science.gov (United States)

Rafael Santiago; Tom Gallagher; Matthew Smidt; Dana Mitchell

2016-01-01

Renewable fuels are being tested as an alternative for fossil fuels. For the Southeast U.S., the use of woody biomass has proven to be an excellent source of renewable energy in terms of cost benefit and availability. Short rotation woody crops (SRWC) are timber plantations with exclusive characteristics that can meet the intensive demand for wood due to their fast...

Solvent-shared pairs of densely charged ions induce intense but short-range supra-additive slowdown of water rotation.

Science.gov (United States)

Vila Verde, Ana; Santer, Mark; Lipowsky, Reinhard

2016-01-21

The question "Can ions exert supra-additive effects on water dynamics?" has had several opposing answers from both simulation and experiment. We address this ongoing controversy by investigating water reorientation in aqueous solutions of two salts with large (magnesium sulfate) and small (cesium chloride) effects on water dynamics using molecular dynamics simulations and classical, polarizable models. The salt models are reparameterized to reproduce properties of both dilute and concentrated solutions. We demonstrate that water rotation in concentrated MgSO4 solutions is unexpectedly slow, in agreement with experiment, and that the slowdown is supra-additive: the observed slowdown is larger than that predicted by assuming that the resultant of the extra forces induced by the ions on the rotating water molecules tilts the free energy landscape associated with water rotation. Supra-additive slow down is very intense but short-range, and is strongly ion-specific: in contrast to the long-range picture initially proposed based on experiment, we find that intense supra-additivity is limited to water molecules directly bridging two ions in solvent-shared ion pair configuration; in contrast to a non-ion-specific origin to supra-additive effects proposed from simulations, we find that the magnitude of supra-additive slowdown strongly depends on the identity of the cations and anions. Supra-additive slowdown of water dynamics requires long-lived solvent-shared ion pairs; long-lived ion pairs should be typical for salts of multivalent ions. We discuss the origin of the apparent disagreement between the various studies on this topic and show that the short-range cooperative slowdown scenario proposed here resolves the existing controversy.

Improving the water use efficiency of short rotation coppice (SRC) willows

Energy Technology Data Exchange (ETDEWEB)

Stephens, W.; Bonneau, L.; Groves, S.; Armstrong, A.; Lindegard, K.

2003-07-01

On the premise that biofuels will make a significant contribution to the UK's renewable energy sources by the year 2010, willow short rotation coppicing is being studied. The high water requirement of willow is seen as a potential problem in the drier regions of the UK and increasing the water use efficiency and/or draught resistance would extend the areas where willow coppicing would be profitable. The first part of the project was to investigate the water use of a number of near-market varieties of willow and evaluate techniques for early drought tolerance screening in a breeding program and for this, field studies were conducted. This report gives some very early results from the preliminary study. Since DTI funding ceased before the one-season study of the three-year program was complete, the results should be regarded as tentative only. The next phase of the program will be funded by DEFRA and will include efforts to identify how a range of high-yielding willows respond to water stress.

Work analysis of the machine Claas Jaguar 880 employed in short rotation coppice harvesting

Directory of Open Access Journals (Sweden)

Verani S

2010-02-01

Full Text Available Working times observed during different harvesting phases in a poplar short rotation coppice (second rotation were calculated. The main objective of the work was to evaluate the yard productivity and the economic gain in order to furnish good indications to the field operators about the harvesting planning. A comparisons between productivity and economic features was carried out on observed (experimental yard and optimized data (optimized yard, the latter characterized by the absence of the inproductive times due to suboptimal yard organization. The harvested gross time as a function of distance covered by machine was assessed using linear regressions methods. The observed average biomass in plantation was 47.32 t ha-1. The harvesting gross average productivity observed in experimental yard was 34.20 t h-1 and the optimized was 54.16 t h-1. The working ability was 0.76 and 1.18 ha h-1 for experimental and optimized yard, respectively. The final product (chips costs estimated was 9.81 euro t-1 and 444.46 euro ha-1 in the experimental yard. The optimized yard was 22-24% more efficient. This paper demonstrates the feasibilty to estimate harvesting times and costs per hectare using linear regressions with good approximation when the standing biomass in plantation is known.

The role of short rotation coppice technology in fuelwood supply in Rungwe district, Tanzania

Directory of Open Access Journals (Sweden)

G.M. Karwani

2016-06-01

Full Text Available The roles of Short Rotation Coppice (SRC Technology in fuelwood supply and offsetting CO2 emissions in the Tanzania and most African countries remain poorly understood. This study was carried in Rungwe District, Mbeya region in Tanzania, to determine trends, extent and drivers of adoption of SRC; identify various sources of household energy and assess the contribution of SRC to the total household fuelwood needs, and trees and shrub species used as sources of fuelwood. Data were collected using reconnaissance, field and social surveys and was analyzed using the Statistical Package for Social Sciences (SPSS. Results revealed that, 97.5% of local community adopted the SRC technology since 1960s. Eucalyptus spp. are mostly planted in woodlots and field boundaries while Persea americana and Leucaena leucocephala are intercropped in farmlands. The survey indicated that out of 176 tons of fuelwood used annually, 73% comes from SRC technology, 25% from non-SRC technology, and only 2% is purchased to supplement household fuelwood shortage. Local communities depend heavily on biomass energy from woodlots and farmlands where tree species like Eucalyptus spp. plays a key role in meeting the energy demand. This study demonstrates that SRC technologies like woodlots, boundary planting, and intercropping in farmland hold high promise to meet the household energy demand. If promoted and backed with strong policies and supportive land tenure, these technologies may reduce the harvesting pressure on native forests for energy demand and contribute to climate change mitigation and adaptation.

Rotational Rebound Attacks on Reduced Skein

DEFF Research Database (Denmark)

Khovratovich, Dmitry; Nikolic, Ivica; Rechberger, Christian

2010-01-01

In this paper we combine a recent rotational cryptanalysis with the rebound attack, which results in the best cryptanalysis of Skein, a candidate for the SHA-3 competition. The rebound attack approach was so far only applied to AES-like constructions. For the first time, we show that this approach...

Quantifying and Reducing Uncertainty in Correlated Multi-Area Short-Term Load Forecasting

Energy Technology Data Exchange (ETDEWEB)

Sun, Yannan; Hou, Zhangshuan; Meng, Da; Samaan, Nader A.; Makarov, Yuri V.; Huang, Zhenyu

2016-07-17

In this study, we represent and reduce the uncertainties in short-term electric load forecasting by integrating time series analysis tools including ARIMA modeling, sequential Gaussian simulation, and principal component analysis. The approaches are mainly focusing on maintaining the inter-dependency between multiple geographically related areas. These approaches are applied onto cross-correlated load time series as well as their forecast errors. Multiple short-term prediction realizations are then generated from the reduced uncertainty ranges, which are useful for power system risk analyses.

Reducing N losses through surface runoff from rice-wheat rotation by improving fertilizer management.

Science.gov (United States)

Cao, Yansheng; Sun, Huifeng; Liu, Yaqin; Fu, Zishi; Chen, Guifa; Zou, Guoyan; Zhou, Sheng

2017-02-01

To better understand N runoff losses from rice-wheat rotation and demonstrate the effectiveness of improved fertilizer management in reducing N runoff losses, a field study was conducted for three consecutive rice-wheat rotations. Nitrogen losses through surface runoff were measured for five treatments, including CK without N application, C200, C300 simulating the conventional practices, CO200, and CO300. Optimum N rate was applied for C200 and CO200, and 30% of chemical fertilizer was substituted with organic fertilizer for CO200 and CO300 with respect to C200 and C300, respectively. Rice season had higher runoff coefficients than wheat season. Approximately 52% of total N was lost as NH 4 + -N in rice season, ranging from 21 to 83%, and in wheat season, the proportion of NO 3 - -N in total N averaged 53% with a variation from 38 to 67%. The N treatments lost less total N in rice season (1.67-10.7 kg N ha -1 ) than in wheat season (1.72-17.1 kg N ha -1 ). These suggested that a key to controlling N runoff losses from rice-wheat rotation was to limit NO 3 - -N accumulation in wheat season. In both seasons, N runoff losses for C200 and CO300 were lower than those for C300. CO200 better cut N losses than C200 and CO300, with 64 and 57% less N in rice and wheat seasons than C300, respectively. Compared with the conventional practices, optimum N inputs integrated with co-application of organic and chemical fertilizers could reduce N runoff losses with a better N balance under rice-wheat rotation.

Environmental effects of growing short-rotation woody crops on former agricultural lands

International Nuclear Information System (INIS)

Tolbert, V.R.; Thornton, F.C.; Joslin, J.D.

1997-01-01

Field-scale studies in the Southeast have been addressing the environmental effects of converting agricultural lands to biomass crop production since 1994. Erosion, surface water quality and quantity and subsurface movement of water and nutrients from woody crops, switchgrass and agricultural crops are being compared. Nutrient cycling, soil physical changes, and crop productivity are also being monitored at the three sites. Maximum sediment losses occurred in the spring and fall. Losses were greater from sweetgum planted without a cover crop than with a cover crop. Nutrient losses of N and P in runoff and subsurface water occurred primarily after spring fertilizer application. These field plot studies are serving as the basis for a water shed study initiated in 1997. Results from the two studies will be used to develop and model nutrient and hydrologic budgets for woody crop plantings to identify potential constraints to sustainable deployment of short-rotation woody crops in the southeastern United States. (author)

Growth and yield of mixed polyclonal stands of Populus in short-rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Benbrahim, Mohammed; Gavaland, Andre [INRA centre de Toulouse (France). Unite Agroforesterie et foret Paysanne; Gauvin, Jean [INRA centre d' Orleans (France). Unite d' Amelioration des arbres forestiers

2000-07-01

Eight clones of poplar were used to compare the growth and productivity of monoclonal and polyclonal mixed plantations in short-rotation coppice. At the end of the eight growing season, the diameter at breast height (DBH) and height of trees were measured and dry weight and yield were estimated. Polyclonal mixtures did not affect mortality. Few differences in growth were observed between clones in monoclonal plots. Polyclonal mixture slightly affected the growth and tree size of the clones compared with monoclonal plots. No increase in stand heterogeneity in relation to clone deployment was observed. A neighbourhood index was calculated for each tree and was significantly affected by polyclonal mixture. However, the relationship between the neighbourhood index and the DBH indicated that this effect did not cause a great change in DBH. Consequently, dry weight and yield productivity were not affected by clone deployment.

Genetic improvement and evaluation of black cottonwood for short- rotation biomass production. Final report, 1987--1992

Energy Technology Data Exchange (ETDEWEB)

Stettler, R.F.; Hinckley, T.M. [Washington Univ., Seattle, WA (United States). Coll. of Forest Resources; Heilman, P.E. [Washington State Univ., Puyallup, WA (United States). Research and Extension Center; Bradshaw, H.D. Jr. [Washington Univ., Seattle, WA (United States). Dept. of Biochemistry

1993-04-30

This project was initiated in 1978 to serve three objectives: (1) develop genetically improved poplar cultivars offering increased productivity under short-rotation culture; (2) identify the major components of productivity in poplar and determine ways in which they can be manipulated, genetically and culturally; and (3) engage in technology transfer to regional industry and agencies so as to make poplar culture in the Pacific Northwest economically feasible. The project is aimed at capturing natural variation in the native black cottonwood. Populus trichocarpa T & G, and enhancing it through selective breeding. Major emphasis has been placed on hybridization of black cottonwood with P deltoides and P maximowiczii, more recently with p nigra. First-generation (F{sub 1}) hybrids have consistently outperformed black cottonwood by a factor of 1.5.-2. The high yields of woody biomass obtained from these clonally propagated hybrids, in rotations of 4-7 years, have fostered the establishment of large-scale plantations by the pulp and paper industry in the region. Physiological studies have helped to elucidate hybrid superiority and several of the underlying mechanisms.

Water Table Management Reduces Tile Nitrate Loss in Continuous Corn and in a Soybean-Corn Rotation

Directory of Open Access Journals (Sweden)

Craig F. Drury

2001-01-01

Full Text Available Water table management systems can be designed to alleviate soil water excesses and deficits, as well as reduce nitrate leaching losses in tile discharge. With this in mind, a standard tile drainage (DR system was compared over 8 years (1991 to 1999 to a controlled tile drainage/subirrigation (CDS system on a low-slope (0.05 to 0.1% Brookston clay loam soil (Typic Argiaquoll in southwestern Ontario, Canada. In the CDS system, tile discharge was controlled to prevent excessive drainage, and water was pumped back up the tile lines (subirrigation to replenish the crop root zone during water deficit periods. In the first phase of the study (1991 to 1994, continuous corn (Zea mays, L. was grown with annual nitrogen (N fertilizer inputs as per local soil test recommendations. In the second phase (1995 to 1999, a soybean (Glycine max L., Merr.-corn rotation was used with N fertilizer added only during the two corn years. In Phase 1 when continuous corn was grown, CDS reduced total tile discharge by 26% and total nitrate loss in tile discharge by 55%, compared to DR. In addition, the 4-year flow weighted mean (FWM nitrate concentration in tile discharge exceeded the Canadian drinking water guideline (10 mg N l–1 under DR (11.4 mg N l–1, but not under CDS (7.0 mg N l–1. In Phase 2 during the soybean-corn rotation, CDS reduced total tile discharge by 38% and total nitrate loss in tile discharge by 66%, relative to DR. The 4-year FWM nitrate concentration during Phase 2 in tile discharge was below the drinking water guideline for both DR (7.3 mg N l–1 and CDS (4.0 mg N l–1. During both phases of the experiment, the CDS treatment caused only minor increases in nitrate loss in surface runoff relative to DR. Hence CDS decreased FWM nitrate concentrations, total drainage water loss, and total nitrate loss in tile discharge relative to DR. In addition, soybean-corn rotation reduced FWM nitrate concentrations and total nitrate loss in tile discharge

The role of rotational mechanisms in electron swarm parameters at low reduced electric field in N2, O2 and H2

International Nuclear Information System (INIS)

Ridenti, M A; Amorim, J; Alves, L L; Guerra, V

2015-01-01

The homogeneous Boltzmann equation for electrons in N 2 , O 2 and H 2 is solved under the classical two-term approximation, for reduced electric fields in the interval 10   −  4   −10 Td where the electron-neutral encounters are limited to elastic, rotational and vibrational collisions. Rotational excitations/de-excitations are described using the following three different approaches: the discrete inelastic/superelastic collisional operator, written for a number of rotational levels that depends on the molecular gas and the specific rotational cross sections considered; the continuous approximation for rotations; a modified version of the continuous approximation for rotations, including a Chapman–Cowling corrective term proportional to the gas temperature. The expression of the rotational collision operator for this latter approach is deduced here and the results show that it bridges the gap between the discrete and the continuous descriptions at low/intermediate reduced electric fields. The calculations are compared with the measurements for the available swarm parameters to assess the validity of the different approaches and cross sections adopted to describe the rotational mechanisms. (paper)

Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

Science.gov (United States)

Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

2018-03-15

The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

Increased supraspinatus tendon thickness following fatigue loading in rotator cuff tendinopathy: potential implications for exercise therapy

OpenAIRE

McCreesh, Karen M; Purtill, Helen; Donnelly, Alan E; Lewis, Jeremy S

2017-01-01

Background/aim Exercise imparts a load on tendon tissue that leads to changes in tendon properties. Studies suggest that loading immediately reduces tendon thickness, with a loss of this response in symptomatic tendinopathy. No studies investigating the response of tendon dimensions to load for the rotator cuff tendons exist. This study aimed to examine the short-term effect of loading on the thickness of the supraspinatus tendon and acromiohumeral distance those with and without rotator cuff...

How short rotation forest crops can be used for sustainable remediation of contaminated areas

Energy Technology Data Exchange (ETDEWEB)

Thiry, I

1996-09-18

In large territories of the CIS, it becomes obvious from the factual consequences of the Chernobyl environmental contamination that no successful remediation actions can be achieved without considering realistic technical and economical issues. In these conditions, the Short Rotation Forestry concept for energy purposes is proposed as an alternative and integrated approach for the recovery of agricultural practices on waste farm land. This corrective option will be examined with respect to this ecological, economical, and social relevancy. Different aspects of the culture in contaminated areas and of energy production from biomass remain to be investigated, developed and validated in the light of radiation protection criteria. In particular, attention will be drawn on the opportunity of this new concept to be integrated in the development of the site remediation research activities at SCK.CEN.

Modelling short-rotation coppice and tree planting for urban carbon management - a citywide analysis.

Science.gov (United States)

McHugh, Nicola; Edmondson, Jill L; Gaston, Kevin J; Leake, Jonathan R; O'Sullivan, Odhran S

2015-10-01

The capacity of urban areas to deliver provisioning ecosystem services is commonly overlooked and underutilized. Urban populations have globally increased fivefold since 1950, and they disproportionately consume ecosystem services and contribute to carbon emissions, highlighting the need to increase urban sustainability and reduce environmental impacts of urban dwellers. Here, we investigated the potential for increasing carbon sequestration, and biomass fuel production, by planting trees and short-rotation coppice (SRC), respectively, in a mid-sized UK city as a contribution to meeting national commitments to reduce CO 2 emissions.Iterative GIS models were developed using high-resolution spatial data. The models were applied to patches of public and privately owned urban greenspace suitable for planting trees and SRC, across the 73 km 2 area of the city of Leicester. We modelled tree planting with a species mix based on the existing tree populations, and SRC with willow and poplar to calculate biomass production in new trees, and carbon sequestration into harvested biomass over 25 years.An area of 11 km 2 comprising 15% of the city met criteria for tree planting and had the potential over 25 years to sequester 4200 tonnes of carbon above-ground. Of this area, 5·8 km 2 also met criteria for SRC planting and over the same period this could yield 71 800 tonnes of carbon in harvested biomass.The harvested biomass could supply energy to over 1566 domestic homes or 30 municipal buildings, resulting in avoided carbon emissions of 29 236 tonnes of carbon over 25 years when compared to heating by natural gas. Together with the net carbon sequestration into trees, a total reduction of 33 419 tonnes of carbon in the atmosphere could be achieved in 25 years by combined SRC and tree planting across the city. Synthesis and applications . We demonstrate that urban greenspaces in a typical UK city are underutilized for provisioning ecosystem services by trees and

Biomass productivity and water use relation in short rotation poplar coppice (Populus nigra x p. maximowiczii) in the conditions of Czech Moravian Highlands

Czech Academy of Sciences Publication Activity Database

Fischer, Milan; Trnka, Miroslav; Kučera, J.; Fajman, M.; Žalud, Zdeněk

LIX, č. 6 (2011), s. 141-152 ISSN 1211-8516 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : short rotation coppice * biomass increment * water consumption * water use effi ciency Subject RIV: EH - Ecology, Behaviour

Influence of Robinia pseudoacacia short rotation coppice on soil physical properties

Science.gov (United States)

Xavier, Morvan; Isabelle, Bertrand; Gwenaelle, Gibaud

2015-04-01

Human activities can lead to the degradation of soil physical properties. For instance, machinery traffic across the land can induce the development of compacted areas at the wheel tracks. It leads to a decrease in porosity which results in a decrease of the hydraulic conductivity, and therefore, prevents water infiltration and promotes surface runoff. Land use, soil management and soil cover also have a significant influence on soil physical properties (Kodesova et al., 2011). In the arable land, surface runoff and soil erosion are enhanced by the absence of soil cover for part of the year and by the decrease of aggregate stability due to a decline of soil organic matter. In that context, few studies focused on the effects of a Robinia pseudoacacia short rotation coppice (SRC) on soil physical properties. Therefore, this study aims to determine the effect of the conversion of a grassland in a SRC on soil physical properties. These properties have also been compared to those of arable land and natural forest. For that, in several plots of the experimental farm of Grignon (30 km west of Paris, France), different measurements were performed: i) soil water retention on a pressure plate apparatus for 7 water potential between 0 and 1500 kPa, ii) bulk density using the method for gravelly and rocky soil recommended by the USDA, iii) aggregate stability using the method described in Le Bissonnais (1996), and iv) soil hydraulic conductivity using a Guelph permeameter. All these measurements were performed on the same soil type and on different land uses: arable land (AL), grassland (GL), natural forest (NF) and short rotation coppice (SRC) of Robinia pseudoacacia planted 5 years ago. Soil water retention measurements are still under progress and will be presented in congress. Bulk density measurements of the AL, GL and SRC are not significantly different. They ranged from 1.32 to 1.42. Only the NF measurements are significantly lower than the other (0.97). Aggregate

Differential Rotation via Tracking of Coronal Bright Points.

Science.gov (United States)

McAteer, James; Boucheron, Laura E.; Osorno, Marcy

2016-05-01

The accurate computation of solar differential rotation is important both as a constraint for, and evidence towards, support of models of the solar dynamo. As such, the use of Xray and Extreme Ultraviolet bright points to elucidate differential rotation has been studied in recent years. In this work, we propose the automated detection and tracking of coronal bright points (CBPs) in a large set of SDO data for re-evaluation of solar differential rotation and comparison to other results. The big data aspects, and high cadence, of SDO data mitigate a few issues common to detection and tracking of objects in image sequences and allow us to focus on the use of CBPs to determine differential rotation. The high cadence of the data allows to disambiguate individual CBPs between subsequent images by allowing for significant spatial overlap, i.e., by the fact that the CBPs will rotate a short distance relative to their size. The significant spatial overlap minimizes the effects of incorrectly detected CBPs by reducing the occurrence of outlier values of differential rotation. The big data aspects of the data allows to be more conservative in our detection of CBPs (i.e., to err on the side of missing CBPs rather than detecting extraneous CBPs) while still maintaining statistically larger populations over which to study characteristics. The ability to compute solar differential rotation through the automated detection and tracking of a large population of CBPs will allow for further analyses such as the N-S asymmetry of differential rotation, variation of differential rotation over the solar cycle, and a detailed study of the magnetic flux underlying the CBPs.

International evaluation of Swedish research projects in the field of short rotation forestry for energy

Energy Technology Data Exchange (ETDEWEB)

Dawson, W M [N.I. Horticulture and Plant Breeding Station, Armagh (Ireland); Isebrands, J [USDA Forest Service, North Central Forest Experiment Station, Rhinelander, WI (United States); Namkoong, G [Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Forest Sciences; Tahvanainen, J [Univ. of Joensuu (Finland). Dept. of Biology

1996-11-01

The purpose of this evaluation was to inform NUTEK of the scientific quality of the research projects, as seen in an international context. The projects were therefore the main elements considered in the evaluation. The main basis of the evaluation was the scientific quality of the research and its relevance to NUTEK`s aims in the application of industrial research and development. The present report is based on the information contained in the written reports submitted by the grant holders, site visits and discussions between the grant holders and the Committee. The report first gives an overview and general recommendations concerning the overall programme in the field of Short Rotation Forestry for Energy. Thereafter, the 16 projects are evaluated separately

Energy plants increasingly important. Scientific results and practical experiences on the production of biogas plants and short rotation coppices. Symposium; Energiepflanzen im Aufwind. Wissenschaftliche Ergebnisse und praktische Erfahrungen zur Produktion von Biogaspflanzen und Feldholz. Fachtagung

Energy Technology Data Exchange (ETDEWEB)

Heiermann, M.; Scholz, V.; Foltan, H. (comps.)

2007-05-15

The conference proceedings contain 15 contributions on energy plants: energy plant production in Germany - developments and research activities; potentials and constraints of cultivating energy crops; environmental aspects of production and utilization of energy plants; costs of energy crop supply; crops for the biogas production in the territory of Brandenburg; mixed cropping systems on sandy soils - alternative cropping strategies; impact of ensiling process on biogas production - recent research results; solid state anaerobic digestion of renewable biomass sources - state of research and development; energy crops as feedstock in a biogas plant; proffer and demand of wood fuel in the State of Brandenburg; regulatory framework of growing short rotation coppice; mechanization of SRC production; 20 years of short rotation coppice; willow production and marketing in Denmark; short rotation coppice production in Italy.

HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

Energy Technology Data Exchange (ETDEWEB)

Hotta, H.; Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Yokoyama, T., E-mail: hotta@ucar.edu [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2015-01-01

We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ☉} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ☉}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

Cover crop rotations in no-till system: short-term CO2 emissions and soybean yield

Directory of Open Access Journals (Sweden)

João Paulo Gonsiorkiewicz Rigon

Full Text Available ABSTRACT: In addition to improving sustainability in cropping systems, the use of a spring and winter crop rotation system may be a viable option for mitigating soil CO2 emissions (ECO2. This study aimed to determine short-term ECO2 as affected by crop rotations and soil management over one soybean cycle in two no-till experiments, and to assess the soybean yields with the lowest ECO2. Two experiments were carried out in fall-winter as follows: i triticale and sunflower were grown in Typic Rhodudalf (TR, and ii ruzigrass, grain sorghum, and ruzigrass + grain sorghum were grown in Rhodic Hapludox (RH. In the spring, pearl millet, sunn hemp, and forage sorghum were grown in both experiments. In addition, in TR a fallow treatment was also applied in the spring. Soybean was grown every year in the summer, and ECO2 were recorded during the growing period. The average ECO2 was 0.58 and 0.84 g m2 h–1 with accumulated ECO2 of 5,268 and 7,813 kg ha–1 C-CO2 in TR and RH, respectively. Sunn hemp, when compared to pearl millet, resulted in lower ECO2 by up to 12 % and an increase in soybean yield of 9% in TR. In RH, under the winter crop Ruzigrazz+Sorghum, ECO2 were lower by 17%, although with the same soybean yield. Soil moisture and N content of crop residues are the main drivers of ECO2 and soil clay content seems to play an important role in ECO2 that is worthy of further studies. In conclusion, sunn hemp in crop rotation may be utilized to mitigate ECO2 and improve soybean yield.

Water Quality Changes in a Short-Rotation Woody Crop Riparian Buffer

Science.gov (United States)

Rosa, D.; Clausen, J.; Kuzovkina, J.

2016-12-01

Converting riparian buffers in agricultural areas from annual row crops to short rotation woody crops (SRWCs) grown for biofuel can provide both water quality benefits and a financial incentive for buffer adoption among agricultural producers. A randomized complete block design was used to determine water quality changes resulting from converting plots previously cultivated in corn to SRWC willow (Salix. spp) adjacent to a stream in Storrs, CT. Both overland flow and ground water samples were analyzed for total nitrogen (TN), nitrate + nitrite (NO2+NO3-N), and total phosphorus (TP). Overland flow was also analyzed for suspended solids concentration (SSC). Lower (p = 0.05) concentrations of TN (56%) and TP (61%) were observed in post-coppice surface runoff from willow plots than from corn plots. Shallow ground water concentrations at the edge of willow plots were lower in TN (56%) and NO3+NO2-N (64%), but 35% higher in TP, than at the edge of corn plots. SSC was also lower (72%) in overland flow associated with willow compared to corn. The treatment had no effect on discharge or mass export. These results suggest conversion from corn to a SRWC in a riparian area can provide water quality benefits similar to those observed in restored and established buffers.

Climate impact and energy efficiency from electricity generation through anaerobic digestion or direct combustion of short rotation coppice willow

International Nuclear Information System (INIS)

Ericsson, Niclas; Nordberg, Åke; Sundberg, Cecilia; Ahlgren, Serina; Hansson, Per-Anders

2014-01-01

Highlights: • Using LCA, CHP from willow use in biogas was compared with direct combustion. • Direct combustion was ninefold more energy-efficient. • Biogas had a much greater cooling effect on global mean surface temperature. • The effects of soil carbon changes on temperature over time differed. • Biogas had long-term temperature effects, direct combustion short-term effects. - Abstract: Short rotation coppice willow is an energy crop used in Sweden to produce electricity and heat in combined heat and power plants. Recent laboratory-scale experiments have shown that SRC willow can also be used for biogas production in anaerobic digestion processes. Here, life cycle assessment is used to compare the climate impact and energy efficiency of electricity and heat generated by these measures. All energy inputs and greenhouse gas emissions, including soil organic carbon fluxes were included in the life cycle assessment. The climate impact was determined using time-dependent life cycle assessment methodology. Both systems showed a positive net energy balance, but the direct combustion system delivered ninefold more energy than the biogas system. Both systems had a cooling effect on the global mean surface temperature change. The cooling impact per hectare from the biogas system was ninefold higher due to the carbon returned to soil with the digestate. Compensating the lower energy production of the biogas system with external energy sources had a large impact on the result, effectively determining whether the biogas scenario had a net warming or cooling contribution to the global mean temperature change per kWh of electricity. In all cases, the contribution to global warming was lowered by the inclusion of willow in the energy system. The use of time-dependent climate impact methodology shows that extended use of short rotation coppice willow can contribute to counteract global warming

Shoot allometry and biomass productivity in poplar and willow varieties grown as short rotation coppice. Summary of results 1995-2000

Energy Technology Data Exchange (ETDEWEB)

Matthews, R.; Henshall, P.; Tubby, I.

2003-07-01

This report summarises the results of a 4 year study assessing shoot diameters and lengths using non-destructive measurements in order to establish allometric relationships between biomass and non-destructive measurements and also to provide estimates of increments for the development of a model of short rotation cultivation growth and yield. Details are given of the basic methodology and measurement conventions; the data preparation, quality assurance classification and storage; and shoot diameter and length assessments and allometry analyses.

Faster in-plane switching and reduced rotational viscosity characteristics in a graphene-nematic suspension

Science.gov (United States)

Basu, Rajratan; Kinnamon, Daniel; Skaggs, Nicole; Womack, James

2016-05-01

The in-plane switching (IPS) for a nematic liquid crystal (LC) was found to be considerably faster when the LC was doped with dilute concentrations of monolayer graphene flakes. Additional studies revealed that the presence of graphene reduced the rotational viscosity of the LC, permitting the nematic director to respond quicker in IPS mode on turning the electric field on. The studies were carried out with several graphene concentrations in the LC, and the experimental results coherently suggest that there exists an optimal concentration of graphene, allowing a reduction in the IPS response time and rotational viscosity in the LC. Above this optimal graphene concentration, the rotational viscosity was found to increase, and consequently, the LC no longer switched faster in IPS mode. The presence of graphene suspension was also found to decrease the LC's pretilt angle significantly due to the π-π electron stacking between the LC molecules and graphene flakes. To understand the π-π stacking interaction, the anchoring mechanism of the LC on a CVD grown monolayer graphene film on copper substrate was studied by reflected crossed polarized microscopy. Optical microphotographs revealed that the LC alignment direction depended on monolayer graphene's hexagonal crystal structure and its orientation.

Faster in-plane switching and reduced rotational viscosity characteristics in a graphene-nematic suspension

International Nuclear Information System (INIS)

Basu, Rajratan; Kinnamon, Daniel; Skaggs, Nicole; Womack, James

2016-01-01

The in-plane switching (IPS) for a nematic liquid crystal (LC) was found to be considerably faster when the LC was doped with dilute concentrations of monolayer graphene flakes. Additional studies revealed that the presence of graphene reduced the rotational viscosity of the LC, permitting the nematic director to respond quicker in IPS mode on turning the electric field on. The studies were carried out with several graphene concentrations in the LC, and the experimental results coherently suggest that there exists an optimal concentration of graphene, allowing a reduction in the IPS response time and rotational viscosity in the LC. Above this optimal graphene concentration, the rotational viscosity was found to increase, and consequently, the LC no longer switched faster in IPS mode. The presence of graphene suspension was also found to decrease the LC's pretilt angle significantly due to the π-π electron stacking between the LC molecules and graphene flakes. To understand the π-π stacking interaction, the anchoring mechanism of the LC on a CVD grown monolayer graphene film on copper substrate was studied by reflected crossed polarized microscopy. Optical microphotographs revealed that the LC alignment direction depended on monolayer graphene's hexagonal crystal structure and its orientation.

Faster in-plane switching and reduced rotational viscosity characteristics in a graphene-nematic suspension

Energy Technology Data Exchange (ETDEWEB)

Basu, Rajratan, E-mail: basu@usna.edu; Kinnamon, Daniel; Skaggs, Nicole; Womack, James [Soft Matter and Nanomaterials Laboratory, Department of Physics, The United States Naval Academy, Annapolis, Maryland 21402 (United States)

2016-05-14

The in-plane switching (IPS) for a nematic liquid crystal (LC) was found to be considerably faster when the LC was doped with dilute concentrations of monolayer graphene flakes. Additional studies revealed that the presence of graphene reduced the rotational viscosity of the LC, permitting the nematic director to respond quicker in IPS mode on turning the electric field on. The studies were carried out with several graphene concentrations in the LC, and the experimental results coherently suggest that there exists an optimal concentration of graphene, allowing a reduction in the IPS response time and rotational viscosity in the LC. Above this optimal graphene concentration, the rotational viscosity was found to increase, and consequently, the LC no longer switched faster in IPS mode. The presence of graphene suspension was also found to decrease the LC's pretilt angle significantly due to the π-π electron stacking between the LC molecules and graphene flakes. To understand the π-π stacking interaction, the anchoring mechanism of the LC on a CVD grown monolayer graphene film on copper substrate was studied by reflected crossed polarized microscopy. Optical microphotographs revealed that the LC alignment direction depended on monolayer graphene's hexagonal crystal structure and its orientation.

Immobilization in external rotation combined with abduction reduces the risk of recurrence after primary anterior shoulder dislocation.

Science.gov (United States)

Heidari, Kamran; Asadollahi, Shadi; Vafaee, Reza; Barfehei, Abbas; Kamalifar, Hossein; Chaboksavar, Zein Alabedin; Sabbaghi, Mohammad

2014-06-01

We aimed to compare the effectiveness of immobilization in abduction and external rotation vs immobilization in adduction and internal rotation after primary anterior dislocation of the shoulder. The study randomized 102 patients (age range, 15-55 years) with the diagnosis of primary anterior dislocation of the shoulder to receive immobilization in adduction and internal rotation (AdIR, n = 51) using sling and swathe bandage or immobilization in abduction and external rotation (AbER, n = 51) with a stabilizer brace. Patients received a rehabilitation program 3 weeks after the intervention. After a 24-month follow-up, 33.3% in the AdIR group and 3.9% in the AbER group had recurrence (P patients in the AbER group (19.6%) and 3 in the AdIR group (5.8%) discontinued shoulder immobilization before 3 weeks (P = .03). In patients without recurrence, the anterior apprehension test was positive in 6 of 34 in the AdIR group (17.6%) and in 4 of 49 in the AbER group (8.1%, P = .19). Immobilization with the shoulder joint in abduction and external rotation is an effective method to reduce the risk of recurrence after primary anterior shoulder dislocations and should be preferred to the traditional method of immobilization in adduction and internal rotation in clinical practice. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

A further evaluation of herbicides for post-emergence use in short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D.J.

2002-07-01

This report describes a study of the safety and efficacy of a range of herbicides and mixtures of herbicides (with both contact and residual activity) for the post-emergence control of weeds in newly planted willow short rotation coppice (SRC). Severe competition from weeds that have not been controlled adequately by pre-emergence herbicide application is one of the commonest causes of SRC crop failure. In the study, the effects of 11 herbicide treatments currently recommendation for weed control with cereals, legumes or potatoes were compared with an untreated control. There was minimal crop death from any treatment, though most of the treatments caused varying degrees of phytotoxicity. Two commercial products, Reflex T and Impuls, gave the best overall crop safety and weed control results. The report provides growers of SRC and their advisors with some information on how to achieve improved weed control in SRC fields, and recommends that British Biogen (the trade industry body) should consider the compilation of a technical register of herbicide applications based on information supplied by growers and advisers, including field treatment details.

An evaluation of harvesting machinery for short rotation coppice willow in Denmark

Energy Technology Data Exchange (ETDEWEB)

Kofman, P.D.; Spinelli, R.

1997-12-31

During the harvesting seasons 1994-1995 and 1995-1996 several harvesting trials were carried out within the EU project on harvesting and storage of Short Rotation Crops and within a national project. During this period the following machines were investigated: Diemelstadt poplar harvester, cut and chip; Claas forage harvester with SRF header, cut and chip; Austoft sugarcane harvester, adapted to SRF, cut and chip; Bender II, cut and chip; Hvidsted Energy Allrounder, whole shoot harvester; Dansalix whole shoot harvester. In the 1994-1995 season the intention was to harvest 300 tonnes of whole shoots, chunks and chips for a storage trial. The main conclusions of the 1994-1995 harvesting season must be that harvesting willow with the existing machines in wet winters without frozen ground is very difficult. The machines will have to be developed further and special interest should be given to developing shuttle vehicles with the same flotation as the tracked harvester. Several of the problems encountered with the machines in Denmark were confirmed by the experience in the other trials. Road transportation of chips from SRF plantations is just as expensive as transporting energy chips from the forest at about Dkr 50 per tonne over 48 km. Transporting whole shoots is very expensive due to the low bulk density. Transportation of whole shoots over 48 km costs on the average Dkr 133 per tonne fresh. A very short pilot study into chipping of whole shoots from a three metre high pile indicated that this comminution with a normal forest chipper has a low productivity (8.9 tonnes fresh per work place hour) and is very expensive at Dkr 157 per tonne. This productivity can be improved by equipping the chipper with a special feeding table and better feed rollers for the SRF crop. (EG)

Reduced short-term memory capacity in Alzheimer's disease: the role of phonological, lexical, and semantic processing.

Science.gov (United States)

Caza, Nicole; Belleville, Sylvie

2008-05-01

Individuals with Alzheimer's disease (AD) are often reported to have reduced verbal short-term memory capacity, typically attributed to their attention/executive deficits. However, these individuals also tend to show progressive impairment of semantic, lexical, and phonological processing which may underlie their low short-term memory capacity. The goals of this study were to assess the contribution of each level of representation (phonological, lexical, and semantic) to immediate serial recall performance in 18 individuals with AD, and to examine how these linguistic effects on short-term memory were modulated by their reduced capacity to manipulate information in short-term memory associated with executive dysfunction. Results showed that individuals with AD had difficulty recalling items that relied on phonological representations, which led to increased lexicality effects relative to the control group. This finding suggests that patients have a greater reliance on lexical/semantic information than controls, possibly to make up for deficits in retention and processing of phonological material. This lexical/semantic effect was not found to be significantly correlated with patients' capacity to manipulate verbal material in short-term memory, indicating that language processing and executive deficits may independently contribute to reducing verbal short-term memory capacity in AD.

Reduced plantar sole sensitivity facilitates early adaptation to a visual rotation pointing task when standing upright

Directory of Open Access Journals (Sweden)

Maxime Billot

2016-09-01

Full Text Available Humans are capable of pointing to a target with accuracy. However, when vision is distorted through a visual rotation or mirror-reversed vision, the performance is initially degraded and thereafter improves with practice. There are suggestions this gradual improvement results from a sensorimotor recalibration involving initial gating of the somatosensory information from the pointing hand. In the present experiment, we examined if this process interfered with balance control by asking participants to point to targets with a visual rotation from a standing posture. This duality in processing sensory information (i.e., gating sensory signals from the hand while processing those arising from the control of balance could generate initial interference leading to a degraded pointing performance. We hypothesized that if this is the case, the attenuation of plantar sole somatosensory information through cooling could reduce the sensorimotor interference, and facilitate the early adaptation (i.e. improvement in the pointing task. Results supported this hypothesis. These observations suggest that processing sensory information for balance control interferes with the sensorimotor recalibration process imposed by a pointing task when vision is rotated.

In Situ Groundwater Denitrification in the Riparian Zone of a Short-Rotation Woody Crop Experimental Watershed

Science.gov (United States)

Jeffers, J. B.; Jackson, C. R.; Rau, B.; Pringle, C. M.; Matteson, C.

2017-12-01

The southeastern United States has potential to become a major producer of short rotation woody crops (SRWC) for the production of biofuels, but this will require converting to more intensive forest management practices that will increase nitrate (NO3-) loading and alter nitrogen cycling in nearby freshwater ecosystems. Water quality monitoring in an experimental short-rotation woody crop watershed in the Coastal Plain of South Carolina has shown increased concentrations of NO3- in groundwater but no evidence of increased NO3- in riparian groundwater or surface waters. Forested riparian areas established as streamside management zones (SMZ) are known to act as buffers to surface water bodies by mitigating nutrients. The objectives of this study were to quantify denitrification by measuring dinitrogen (N2) and nitrous oxide (N2O) concentrations along groundwater flow paths and analyze relationships between denitrification estimates, nutrients, and water chemistry parameters. A network of piezometers has been established in the Fourmile Experimental Watershed at the Department of Energy - Savannah River Site. Water samples were collected monthly and were analyzed for concentrations of nutrients (temperature, specific conductivity, dissolved oxygen, pH, dissolved organic carbon) and dissolved gases (N2, Ar, N2O). Preliminary data showed greater dissolved N2O concentrations than dissolved N2 concentrations in groundwater. The ratios of N2O to combined end products of denitrification (N2O / N2O+N2) ranged from 0.33 to 0.99. Mean N2O+N2 concentrations were greater in groundwater samples in the SRWC plot and along the SMZ boundary than along the ephemeral stream within the riparian zone. Correlations between water chemistry parameters and N2 concentrations are indicative of known biogeochemical driving factors of denitrification. Continued monthly sampling will be coupled with analysis of nutrient concentrations (NO3-, NH4+, TN) to help determine transport and processing

Effect of reducing abdominal compression during prone CT colonography on ascending colonic rotation during supine-to-prone positional change

International Nuclear Information System (INIS)

Jang, Jong eon; Park, Seong Ho; Lee, Jong Seok; Kim, Hyun Jin; KIm, Ah Young; Ha, Hyun Kwon

2016-01-01

To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps ≥ 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (°) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180° and +180° (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22° to 61° (median, 13.9°) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10°. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position

Short uncemented stems allow greater femoral flexibility and may reduce peri-prosthetic fracture risk: a dry bone and cadaveric study.

Science.gov (United States)

Jones, Christopher; Aqil, Adeel; Clarke, Susannah; Cobb, Justin P

2015-09-01

Short femoral stems for uncemented total hip arthroplasty have been introduced as a safe alternative to traditional longer stem designs. However, there has been little biomechanical examination of the effects of stem length on complications of surgery. This study aims to examine the effect of femoral stem length on torsional resistance to peri-prosthetic fracture. We tested 16 synthetic and two paired cadaveric femora. Specimens were implanted and then rapidly rotated until fracture to simulate internal rotation on a planted foot, as might occur during stumbling. 3D planning software and custom-printed 3D cutting guides were used to enhance the accuracy and consistency of our stem insertion technique. Synthetic femora implanted with short stems fractured at a significantly higher torque (27.1 vs. 24.2 Nm, p = 0.03) and angle (30.3° vs. 22.3°, p = 0.002) than those implanted with long stems. Fracture patterns of the two groups were different, but showed remarkable consistency within each group. These characteristic fracture patterns were closely replicated in the pair of cadaveric femora. This new short-stemmed press-fit femoral component allows more femoral flexibility and confers a higher resistance to peri-prosthetic fracture from torsional forces than long stems.

Different growth strategies determine the carbon gain and productivity of aspen collectives to be used in short-rotation plantations

International Nuclear Information System (INIS)

Müller, Annika; Horna, Viviana; Zhang, Chunxia; Leuschner, Christoph

2012-01-01

Populus tremula is a favoured tree species in short-rotation forestry with a recognised large intraspecific variation in productivity. We compared the growth potential of 1-yr-old saplings of four Central European aspen collectives with different climate adaptation on a low-fertility site and searched for growth-determining physiological and morphological traits and their dependence on genetic constitution. Among the 35 investigated traits were photosynthetic capacity and mean assimilation rate, quantum yield and carboxylation efficiency, leaf water potential, leaf phaenology and the ratio of leaves lost to leaves produced (LP ratio), leaf size and total leaf area, axes length growth and canopy carbon gain as an estimate of productivity. The collectives differed by more than 30% in cumulative carbon gain with a large genotype effect, while mean assimilation rate and most photosynthetic and water status traits showed a relatively small intraspecific variation with no significant influence on the variation in C gain. The timing of the beginning of net leaf loss (leaf abscission > leaf production) in August differed between the four collectives and resulted in different maximum leaf areas and LP ratios, which were identified as key factors controlling C gain. Mean assimilation rate, though not related to cumulative C gain, was positively correlated with the light, CO 2 and water use efficiencies of photosynthesis. We conclude that genotype selection for high-yielding aspen in short-rotation forestry at low-fertility sites should focus on the parameters leaf phaenology, LP ratio at the end of the growing season, and the resulting total leaf area as key traits.

Dynamic visual noise reduces confidence in short-term memory for visual information.

Science.gov (United States)

Kemps, Eva; Andrade, Jackie

2012-05-01

Previous research has shown effects of the visual interference technique, dynamic visual noise (DVN), on visual imagery, but not on visual short-term memory, unless retention of precise visual detail is required. This study tested the prediction that DVN does also affect retention of gross visual information, specifically by reducing confidence. Participants performed a matrix pattern memory task with three retention interval interference conditions (DVN, static visual noise and no interference control) that varied from trial to trial. At recall, participants indicated whether or not they were sure of their responses. As in previous research, DVN did not impair recall accuracy or latency on the task, but it did reduce recall confidence relative to static visual noise and no interference. We conclude that DVN does distort visual representations in short-term memory, but standard coarse-grained recall measures are insensitive to these distortions.

Reduced muscle fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears.

Science.gov (United States)

Mendias, Christopher L; Roche, Stuart M; Harning, Julie A; Davis, Max E; Lynch, Evan B; Sibilsky Enselman, Elizabeth R; Jacobson, Jon A; Claflin, Dennis R; Calve, Sarah; Bedi, Asheesh

2015-01-01

A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. The contractility of muscle fibers from biopsy specimens of supraspinatus muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis muscle fibers. Correlations between muscle fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. Torn supraspinatus muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus muscle fibers. Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional muscle dysfunction of the residual muscle fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore muscle function after the repair of chronically torn rotator cuff muscles. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Limitations for phytoextraction management on metal-polluted soils with poplar short rotation coppice-evidence from a 6-year field trial.

Science.gov (United States)

Michels, E; Annicaerta, B; De Moor, S; Van Nevel, L; De Fraeye, M; Meiresonne, L; Vangronsveld, J; Tack, F M G; Ok, Y S; Meers, Erik

2018-01-02

Poplar clones were studied for their phytoextraction capacity in the second growth cycle (6-year growth) on a site in the Belgian Campine region, which is contaminated with Cd and Zn via historic atmospheric deposition of nearby zinc smelter activities. The field trial revealed regrowth problems for some clones that could not be predicted in the first growth cycle. Four allometric relations were assessed for their capacity to predict biomass yield in the second growth cycle. A power function based on the shoot diameter best estimates the biomass production of poplar with R 2 values between 0.94 and 0.98. The woody biomass yield ranged from 2.1 to 4.8 ton woody Dry Mass (DM) ha -1 y -1 . The primary goal was to reduce soil concentrations of metals caused by phytoextraction. Nevertheless, increased metal concentrations were determined in the topsoil. This increase can partially be explained by the input of metals from deeper soil layers in the top soil through litterfall. The phytoextraction option with poplar short rotation coppice in this setup did not lead to the intended soil remediation in a reasonable time span. Therefore, harvest of the leaf biomass is put forward as a crucial part of the strategy for soil remediation through Cd/Zn phytoextraction.

Changes in soil quality following poplar short-rotation forestry under different cutting cycles

Directory of Open Access Journals (Sweden)

Claudia Di Bene

2011-02-01

Full Text Available In the last decade, the change of energy concept induced by global warming and fossil fuel depletion together with the advances in agriculture towards a multifunctional and a more sustainable use of rural areas promoted the development of biomass crops. In this regard, Populus is largely utilised in short-rotation forestry (SRF, as it is known to be a fast-growing tree, producing large yields and having a high energy potential. Most studies focused on economic-productive and energetic aspects of Populus plantations, whereas their impact on soil quality and health have been poorly investigated. In this study, the main soil chemical parameters, microbial biomass and activity were assessed aiming at evaluating the impact of Populus SRF under one, two and three-year cutting cycles (T1, T2 and T3 in comparison with an intensive food cropping system (wheat-soybean rotation, WS. In addition, arbuscular mycorrhizal (AM fungal inoculum potential was measured using root colonisation (RC and number of entry points (EP. In the 0-10 cm soil depth, pH, phosphorus (P, total nitrogen (N and soil organic carbon (SOC were significantly affected by the management. In comparison with WS, Populus SRF treatments produced significant pH decreases together with N and SOC increases, these last ones ranging from 11 to 34% and from 21 to 57%, respectively. Under T3 soil pH decreased of 0.25 units, while P, N and SOC increased of 10, 34 and 57%, respectively, in comparison with WS. Microbial biomass and soil respiration under SRF showed also mean increases of 71 and 17%, respectively. Under SRF treatments, Lolium perenne, commonly observed in all field plots, was more than twofold colonised by AM fungi in comparison with WS, while the number of EP, observed on Lactuca sativa used as a test plant, showed values ranging from 8 to 21 times higher. The present study shows the potential of a Populus SRF to improve soil chemical, biochemical and biological quality parameters in

Rotational instability in a linear theta pinch

International Nuclear Information System (INIS)

Ekdahl, C.; Bartsch, R.R.; Commisso, R.J.; Gribble, R.F.; McKenna, K.F.; Miller, G.; Siemon, R.E.

1980-01-01

The m=1 ''wobble'' instability of the plasma column in a 5-m linear theta pinch has been studied using an axial array of orthogonally viewing position detectors to resolve the wavelength and frequency of the column motion. The experimental results are compared with recent theoretical predictions that include finite Larmor orbit effects. The frequency and wavelength characteristics at saturation agree with the predicted dispersion relation for a plasma rotating faster than the diamagnetic drift speed. Measurements of the magnetic fields at the ends of the pinch establish the existence of currents flowing in such a way that they short out the radial electric fields in the plasma column. The magnitude of rotation, the observed delay in the onset of m=1 motion, and the magnitude of end-shorting currents can all be understood in terms of the torsional Alfven waves that communicate to the central plasma column the information that the ends have been shorted. The same waves are responsible for the torque which rotates the plasma and leads to the observed m=1 instability. Observations of the plasma in the presence of solid end plugs indicate a stabilization of high-m number modes and a reduction of the m=1 amplitude

Short rotation coppice with Robinia pseudoacacia L. : a land use option for carbon sequestration on reclaimed mine sites

Energy Technology Data Exchange (ETDEWEB)

Quinkenstein, A.; Bohm, C.; Freese, D. [Brandenburg Univ. of Technology, Cottbus (Germany). Soil Protection and Recultivation; Huttl, R.R. [Brandenburg Univ. of Technology, Cottbus (Germany). Soil Protection and Recultivation; GFZ German Research Centre for Geosciences, Potsdam (Germany)

2010-07-01

A study in northeast Germany has shown that the establishment of short rotation coppices (SRC) of Robinia pseudoacacia L. may be a viable option for improving farmers income on marginal soils. The plantations produce woody biomass at a fast rate for energy use. Carbon is accumulated in the harvestable biomass, as well as in the stump and the roots. These plant compartments form a long-term carbon storage pool because they can survive a harvest, stay vital at the site and continue to grow as the plant ages. As organic litter decomposes, additional carbon is sequestered under SRC as soil organic carbon. The carbon sequestration in SRC of R. pseudoacacia on mining sites within the Lower Lusatian region in northeast Germany was studied and the results were complemented with findings of current field studies conducted on reclaimed mine sites. The average above ground dry matter productivity of R. pseudoacacia was found to be 3 to 10 Mg per hectare per year, depending on the plantation age and rotation period. It has been estimated that the carbon storage within the soil accounts to a carbon sequestration of up to 6 Mg per hectare per year for a soil depth of 60 cm.

Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

International Nuclear Information System (INIS)

SivaRanjan, Uppala; Ramachandran, Ramesh

2014-01-01

A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R 2 ) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R 2 experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR

Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

Energy Technology Data Exchange (ETDEWEB)

SivaRanjan, Uppala; Ramachandran, Ramesh, E-mail: rramesh@iisermohali.ac.in [Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Manauli, P.O. Box-140306, Mohali, Punjab (India)

2014-02-07

A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R{sup 2}) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R{sup 2} experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR.

Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

International Nuclear Information System (INIS)

Loon, Jack J. W. A. van

2016-01-01

Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

Energy Technology Data Exchange (ETDEWEB)

Loon, Jack J. W. A. van, E-mail: j.vanloon@vumc.nl [Department of Oral and Maxillofacial Surgery / Oral Pathology, Dutch Experiment Support Center, VU University Medical Center and Academic Centre for Dentistry Amsterdam, Amsterdam (Netherlands); TEC-MMG LIS Lab, European Space Agency Technology Center, Noordwijk (Netherlands)

2016-07-19

Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

Lipkin-Nogami method for rotating nuclei

International Nuclear Information System (INIS)

Magierski, P.

1993-01-01

The extension of Lipkin-Nogami method to the case of rotating nuclei, where the short-range attraction acting between the nucleus (pairing free) plays a significant role for the coupling scheme is discussed. 7 refs, 6 figs

Pictorial Visual Rotation Ability of Engineering Design Graphics Students

Science.gov (United States)

Ernst, Jeremy Vaughn; Lane, Diarmaid; Clark, Aaron C.

2015-01-01

The ability to rotate visual mental images is a complex cognitive skill. It requires the building of graphical libraries of information through short or long term memory systems and the subsequent retrieval and manipulation of these towards a specified goal. The development of mental rotation skill is of critical importance within engineering…

Monitoring the progress of NFFO-3 projects: short rotation willow coppice - agronomy and economics

International Nuclear Information System (INIS)

Twemlow, R.K.M.

1997-01-01

The involvement of Sidney C. Banks p.l.c., and the subsidiary company Banks Agriculture, in fuel supply for biofuelled power stations started some 4 years ago. When identifying possible opportunities and crops it was apparent that, with the third tranche of Non-Fossil Fuel Obligations (NFFO3) coming up, there were companies looking at developing biofuelled power stations, using Short Rotation Coppice (SRC) and for this they needed to link with potential fuel suppliers. Sidney C. Banks p.l.c. linked with South Western Power (SWP) (a subsidiary of South Western Electricity p.l.c. (SWEB)) to act as their sole fuel supplier on projected biofuel wood power stations. Subsequently two wood fuelled power stations were awarded to SWP and Sidney C. Banks p.l.c. in the 3rd Tranche from NFFO, in December 1994. The objectives of this project were to: establish a network of SRC growers to produce fuel for a NFFO project; monitor the success of the enterprise; implement a programme of constant improvement to optimise the fuel supply strategy; and provide valuable information as to the performance of the SRC crop in large scale commercial production. (author)

An Improved Model of Cryogenic Propellant Stratification in a Rotating, Reduced Gravity Environment

Science.gov (United States)

Oliveira, Justin; Kirk, Daniel R.; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

2007-01-01

This paper builds on a series of analytical literature models used to predict thermal stratification within rocket propellant tanks. The primary contribution to the literature is to add the effect of tank rotation and to demonstrate the influence of rotation on stratification times and temperatures. This work also looks levels of thermal stratification for generic propellant tanks (cylindrical shapes) over a parametric range of upper-stage coast times, heating levels, rotation rates, and gravity levels.

Tilt stability of rotating current rings with passive conductors

International Nuclear Information System (INIS)

Zweibel, E.G.; Pomphrey, N.

1984-12-01

We study the combined effects of rotation and resistive passive conductors on the stability of a rigid current in an external magnetic field. We present numerical and approximate analytical solutions to the equations of motion, which show that the ring is always tilt unstable on the resistive decay timescale of the conductors, although rotation and eddy currents may stabilize it over short times. Possible applications of our model include spheromaks which rotate or which are encircled by energetic particle rings

Rotational excitation of H2O by para-H2 from an adiabatically reduced dimensional potential.

Science.gov (United States)

Scribano, Yohann; Faure, Alexandre; Lauvergnat, David

2012-03-07

Cross sections and rate coefficients for low lying rotational transitions in H(2)O colliding with para-hydrogen pH(2) are computed using an adiabatic approximation which reduces the dimensional dynamics from a 5D to a 3D problem. Calculations have been performed at the close-coupling level using the recent potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)]. A good agreement is found between the reduced adiabatic calculations and the 5D exact calculations, with an impressive time saving and memory gain. This adiabatic reduction of dimensionality seems very promising for scattering studies involving the excitation of a heavy target molecule by a light molecular projectile. © 2012 American Institute of Physics

Response surface methodology to simplify calculation of wood energy potency from tropical short rotation coppice species

Science.gov (United States)

Haqiqi, M. T.; Yuliansyah; Suwinarti, W.; Amirta, R.

2018-04-01

Short Rotation Coppice (SRC) system is an option to provide renewable and sustainable feedstock in generating electricity for rural area. Here in this study, we focussed on application of Response Surface Methodology (RSM) to simplify calculation protocols to point out wood chip production and energy potency from some tropical SRC species identified as Bauhinia purpurea, Bridelia tomentosa, Calliandra calothyrsus, Fagraea racemosa, Gliricidia sepium, Melastoma malabathricum, Piper aduncum, Vernonia amygdalina, Vernonia arborea and Vitex pinnata. The result showed that the highest calorific value was obtained from V. pinnata wood (19.97 MJ kg-1) due to its high lignin content (29.84 %, w/w). Our findings also indicated that the use of RSM for estimating energy-electricity of SRC wood had significant term regarding to the quadratic model (R2 = 0.953), whereas the solid-chip ratio prediction was accurate (R2 = 1.000). In the near future, the simple formula will be promising to calculate energy production easily from woody biomass, especially from SRC species.

Predictive models of biomass for poplar and willow. Short rotation coppice in the United Kingdom

Energy Technology Data Exchange (ETDEWEB)

Brewer, A.C.; Morgan, G.W.; Poole, E.J.; Baldwin, M.E.; Tubby, I. (Biometrics, Surveys and Statistics Division, Forest Research, Farnham (United Kingdom))

2007-07-01

A series of forty-nine experimental trials on short rotation coppice (SRC) were conducted throughout the United Kingdom using a selection of varieties of poplar and willow with the aim of evaluating their performance for wood fuel production under a representative range of UK conditions. Observations on the crops and on a range of site and climatic conditions during the growth of the crops were taken over two three-year cutting cycles. These observations were used to develop a suite of empirical models for poplar and willow SRC growth and yield from which systems were constructed to provide a- priori predictions of biomass yield for any site in the UK with known characteristics (predictive yield models), and estimates of biomass yield from a standing crop (standing biomass models). The structure of the series of field trials and the consequent approach and methodology used in the construction of the suite of empirical models are described, and their use in predicting biomass yields of poplar and willow SRC is discussed. (orig.)

Outcomes following arthroscopic transosseous equivalent suture bridge double row rotator cuff repair: a prospective study and short-term results

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Imam Mohamed Abdelnabi

2016-01-01

Full Text Available Background: The transosseous-equivalent cross bridge double row (TESBDR rotator cuff (RC repair technique has been developed to optimize healing biology at a repaired RC tendon insertion. It has been shown in the laboratory to improve pressurized contact area and mean foot print pressure when compared with a double row anchor technique. Pressure has been shown to influence healing between tendon and bone, and the tendon compression vector provided by the transosseous-equivalent suture bridges may enhance healing. The purpose was to prospectively evaluate the outcomes of arthroscopic TESBDR RC repair. Methods: Single center prospective case series study. Sixty-nine patients were selected to undergo arthroscopic TESBDR RC repair and were included in the current study. Primary outcome measures included the Oxford Shoulder Score (OSS, the University of California, Los Angeles (UCLA score, the Constant-Murley (CM Score and Range of motion (ROM. Secondary outcome measures included a Visual Analogue Scale (VAS for pain, another VAS for patient satisfaction from the operative procedure, EuroQoL 5-Dimensions Questionnaire (EQ-5D for quality of life assessment. Results: At 24 months post-operative, average OSS score was 44, average UCLA score was 31, average CM score was 88, average forward flexion was 145°, average internal rotation was 35°, average external rotation was 79°, average abduction was 150°, average EQ-5D score was 0.73, average VAS for pain was 2.3, and average VAS for patient satisfaction was 9.2. Conclusion: Arthroscopic TESBDR RC repair is a procedure with good post-operative functional outcome and low re-tear rate based on a short term follow-up.

Silviculture and biology of short-rotation woody crops in temperate regions: Then and now

Energy Technology Data Exchange (ETDEWEB)

Dickmann, Donald I. [Department of Forestry, Michigan State University, East Lansing, MI 48824-1222 (United States)

2006-08-15

Although its roots are in antiquity, the current concept of short-rotation woody crops (SRWC) for fiber and energy evolved scientifically from pioneering tree breeding work begun in the early 20th century. A natural outgrowth of this work was the culture of fast-growing trees on rotations of 1-15 years. Close-spaced tree culture received further impetus with the introduction of the 'silage sycamore' concept in the southeastern US in the mid-1960s and the OPEC oil embargo in 1973, leading to statistically designed trials at numerous locations in North America, Europe, and Scandinavia. Early silvicultural research focused on spacing and species trials, propagation methods, site preparation, weed management, nutrition, growth, and yield. Because these trials were based on small plots, and the importance of pest depredations or site variation were not fully recognized, early biomass yield predictions tended to be overly optimistic. Soon physiologists and ecologists began to unravel the biological characteristics of SRWC plantations and their responses to environment. Knowledge of the influence and diversity of pests-insects, diseases, and animals-provided a necessary reality check. Many hardwood tree species and a few conifers have been evaluated over the years for SRWC in temperate regions of the world. Clones of Populus and Salix, however, became the dominant plantation material because of their inherently rapid growth and ease of propagation by hardwood cuttings. Among conifers, loblolly pine (Pinus taeda) also shows promise. Because genetic variation is readily exploitable in the dominant SRWC taxa, strongly focused breeding programs began to provide highly productive genotypes and seed sources in the last decades of the 20th century. A new plateau, with significant practical potential, was reached in the late 20th century when biotechnological methods were applied to tree taxa. Recently, the DNA in the Populus genome was sequenced. Thus, the few current

Development and demonstration of surveillance and diagnostics of rotating machinery for reducing radiation exposure to nuclear power plant personnel: Final report

International Nuclear Information System (INIS)

Allen, J.W.; Bohanick, J.S.

1988-01-01

This program was designed to reduce radiation exposure to power plant personnel resulting from inspection, maintenance, and repair of rotating equipment. The new rotating machinery monitoring system for this program was installed at GGNS during August 1983. This document provides a functional description of the hardware and software that comprise the system and discusses the application of the monitoring system to achieving overall program goals. The analyses of the monitored rotating machinery during the plant startup phase and after the plant's first fuel cycle are presented in addition to the radiation dose reduction which occurred as a direct and indirect result of the RMSS. The dose reduction program at GGNS is reviewed and recommendations made to incorporate this program with the RMSS. 28 refs., 64 figs., 43 tabs

Immobilization in External Rotation Versus Internal Rotation After Primary Anterior Shoulder Dislocation: A Meta-analysis of Randomized Controlled Trials.

Science.gov (United States)

Whelan, Daniel B; Kletke, Stephanie N; Schemitsch, Geoffrey; Chahal, Jaskarndip

2016-02-01

The recurrence rate after primary anterior shoulder dislocation is high, especially in young, active individuals. Recent studies have suggested external rotation immobilization as a method to reduce the rate of recurrent shoulder dislocation in comparison to traditional sling immobilization. To assess and summarize evidence from randomized controlled trials on the effect of internal rotation versus external rotation immobilization on the rate of recurrence after primary anterior shoulder dislocation. Meta-analysis. PubMed, MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and abstracts from recent proceedings were searched for eligible studies. Two reviewers selected studies for inclusion, assessed methodological quality, and extracted data. Six randomized controlled trials (632 patients) were included in this review. Demographic and prognostic variables measured at baseline were similar in the pooled groups. The average age was 30.1 years in the pooled external rotation group and 30.3 years in the pooled internal rotation group. Two studies found that external rotation immobilization reduced the rate of recurrence after initial anterior shoulder dislocation compared with conventional internal rotation immobilization, whereas 4 studies failed to find a significant difference between the 2 groups. This meta-analysis suggested no overall significant difference in the rate of recurrence among patients treated with internal rotation versus external rotation immobilization (risk ratio, 0.69; 95% CI, 0.42-1.14; P = .15). There was no significant difference in the rate of compliance between internal and external rotation immobilization (P = .43). The Western Ontario Shoulder Instability Index scores were pooled across 3 studies, and there was no significant difference between the 2 groups (P = .54). Immobilization in external rotation is not significantly more effective in reducing the recurrence rate after primary anterior shoulder dislocation than

Ocean tide models for satellite geodesy and Earth rotation

Science.gov (United States)

Dickman, Steven R.

1991-01-01

A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

Dynamical pairing correlations in rotating nuclei

International Nuclear Information System (INIS)

Szymanski, Z.

1985-01-01

When the atomic nucleus rotates fast enough the static pair correlations may be destroyed. In this situation the pair-vibrations become an important manifestation of the short-range attractive pairing force. The influence of this effect on nuclear properties at high spin is discussed. (orig.)

Multiple operating system rotation environment moving target defense

Science.gov (United States)

Evans, Nathaniel; Thompson, Michael

2016-03-22

Systems and methods for providing a multiple operating system rotation environment ("MORE") moving target defense ("MTD") computing system are described. The MORE-MTD system provides enhanced computer system security through a rotation of multiple operating systems. The MORE-MTD system increases attacker uncertainty, increases the cost of attacking the system, reduces the likelihood of an attacker locating a vulnerability, and reduces the exposure time of any located vulnerability. The MORE-MTD environment is effectuated by rotation of the operating systems at a given interval. The rotating operating systems create a consistently changing attack surface for remote attackers.

Evolution of rotating stars. III. Predicted surface rotation velocities for stars which conserve total angular momentum

International Nuclear Information System (INIS)

Endal, A.S.; Sofia, S.

1979-01-01

Predicted surface rotation velocities are presented for Population I stars at 10, 7, 5, 3, and 1.5M/sub sun/. The surface velocities have been computed for three different cases of angular momentum redistribution: no radial redistribution (rotation on decoupled shells), complete redistribution (rigid-body rotation), and partial redistribution as predicted by detailed consideration of circulation currents in rotation stars. The velocities for these cases are compared to each other and to observed stellar rotation rates (upsilon sin i).Near the main sequence, rotational effects can substantially reduce the moment of inertia of a star, so nonrotating models consistently underestimate the expected velocities for evolving stars. The magnitude of these effects is sufficient to explain the large numbers of Be stars and, perhaps, to explain the bimodal distribution of velocities observed for the O stars.On the red giant branch, angular momentum redistribution reduces the surface velocity by a factor of 2 or more, relative to the velocity expected for no radial redistribution. This removes the discrepancy between predicted and observed rotation rates for the K giants and makes it unlikely that these stars lose significant amounts of angular momentum by stellar winds. Our calculations indicate that improved observations (by the Fourier-transform technique) of the red giants in the Hyades cluster can be used to determine how angular momentum is redistributed by convection

The Potential to Reduce Nitrogen Loss Through Rotating Different Sorghum Varieties in Greenhouse Vegetable Field

Directory of Open Access Journals (Sweden)

KANG Ling-yun

2015-06-01

Full Text Available In North China plain, excessive fertilization in vegetable greenhouse always results in nitrate accumulation in soil and possible nitrogen leaching with potential environmental risk. It is necessary to rotate appropriate catch crop to absorb surplus nitrogen in fallow season and reduce rootzone nitrate level. An experiment was carried out to select suitable sorghum variety as catch crop to reduce nitrogen loss in Beijing suburb. Six common varieties were used in the experiment as conventional catch crop, sweet corn as the control. The results indicated that the biomass, root growth and nitrogen accumulation in shoots of sorghum Jinza 12 were highest in the catch crops. It demonstrated that the variety Jinza 12 was an appropriate catch crop for reducing nitrogen accumulation in surface soil layer compared with sweet corn. Meanwhile, variety Jiliang 2 maintained highest proportion of soil NH4+-N content after urea application, which might be related to the biological nitrification inhibitors (BNI released by the root system of sorghum. It implied that sorghum could be used as catch crop to reduce nitrogen loss through plant extraction i.e. nitrogen uptake and stabilization i.e. BNI inhibition, in comparison with sweet corn.

Current status of rotational atherectomy.

Science.gov (United States)

Tomey, Matthew I; Kini, Annapoorna S; Sharma, Samin K

2014-04-01

Rotational atherectomy facilitates percutaneous coronary intervention for complex de novo lesions with severe calcification. A strategy of routine rotational atherectomy has not, however, conferred reduction in restenosis or major adverse cardiac events. As it is technically demanding, rotational atherectomy is also uncommon. At this 25-year anniversary since the introduction of rotational atherectomy, we sought to review the current state-of-the-art in rotational atherectomy technique, safety, and efficacy data in the modern era of drug-eluting stents, strategies to prevent and manage complications, including slow-flow/no-reflow and burr entrapment, and appropriate use in the context of the broader evolution in the management of stable ischemic heart disease. Fundamental elements of optimal technique include use of a single burr with burr-to-artery ratio of 0.5 to 0.6-rotational speed of 140,000 to 150,000 rpm, gradual burr advancement using a pecking motion, short ablation runs of 15 to 20 s, and avoidance of decelerations >5,000 rpm. Combined with meticulous technique, optimal antiplatelet therapy, vasodilators, flush solution, and provisional use of atropine, temporary pacing, vasopressors, and mechanical support may prevent slow-flow/no-reflow, which in contemporary series is reported in 0.0% to 2.6% of cases. On the basis of the results of recent large clinical trials, a subset of patients with complex coronary artery disease previously assigned to rotational atherectomy may be directed instead to medical therapy alone or bypass surgery. For patients with de novo severely calcified lesions for which rotational atherectomy remains appropriate, referral centers of excellence are required. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

TGF-β Small Molecule Inhibitor SB431542 Reduces Rotator Cuff Muscle Fibrosis and Fatty Infiltration By Promoting Fibro/Adipogenic Progenitor Apoptosis.

Directory of Open Access Journals (Sweden)

Michael R Davies

Full Text Available Rotator cuff tears represent a large burden of muscle-tendon injuries in our aging population. While small tears can be repaired surgically with good outcomes, critical size tears are marked by muscle atrophy, fibrosis, and fatty infiltration, which can lead to failed repair, frequent re-injury, and chronic disability. Previous animal studies have indicated that Transforming Growth Factor-β (TGF-β signaling may play an important role in the development of these muscle pathologies after injury. Here, we demonstrated that inhibition of TGF-β1 signaling with the small molecule inhibitor SB431542 in a mouse model of massive rotator cuff tear results in decreased fibrosis, fatty infiltration, and muscle weight loss. These observed phenotypic changes were accompanied by decreased fibrotic, adipogenic, and atrophy-related gene expression in the injured muscle of mice treated with SB431542. We further demonstrated that treatment with SB431542 reduces the number of fibro/adipogenic progenitor (FAP cells-an important cellular origin of rotator cuff muscle fibrosis and fatty infiltration, in injured muscle by promoting apoptosis of FAPs. Together, these data indicate that the TGF-β pathway is a critical regulator of the degenerative muscle changes seen after massive rotator cuff tears. TGF-β promotes rotator cuff muscle fibrosis and fatty infiltration by preventing FAP apoptosis. TGF-β regulated FAP apoptosis may serve as an important target pathway in the future development of novel therapeutics to improve muscle outcomes following rotator cuff tear.

Review of Alternative Management Options of Vegetable Crop Residues to Reduce Nitrate Leaching in Intensive Vegetable Rotations

Directory of Open Access Journals (Sweden)

Laura Agneessens

2014-12-01

Full Text Available Vegetable crop residues take a particular position relative to arable crops due to often large amounts of biomass with a N content up to 200 kg N ha−1 left behind on the field. An important amount of vegetable crops are harvested during late autumn and despite decreasing soil temperatures during autumn, high rates of N mineralization and nitrification still occur. Vegetable crop residues may lead to considerable N losses through leaching during winter and pose a threat to meeting water quality objectives. However, at the same time vegetable crop residues are a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to harness the full potential of vegetable crop residues. Two fundamentally different crop residue management strategies to reduce N losses during winter in intensive vegetable rotations are reviewed, namely (i on-field management options and modifications to crop rotations and (ii removal of crop residues, followed by a useful and profitable application.

Development and demonstration of surveillance and diagnostics of rotating machinery for reducing radiation exposure to nuclear power plant personnel: Appendices: Final report

International Nuclear Information System (INIS)

Allen, J.W.; Bohanick, J.S.

1988-01-01

This program was designed to reduce radiation exposure to power plant personnel resulting from inspection, maintenance, and repair of rotating equipment. The new rotating machinery monitoring system for this program was installed at GGNS during August 1983. The following nine appendices are presented: signals monitored at GGNS; definition of characterized spectral values; instructions for alignment and balance programs; machine diagrams; FFT program; software module descriptions; sample radiation survey forms used for exposure study; radiation exposure compared to other plants; and a technical section instruction for the vibration monitoring program at GGNS

Reduced fine-scale spatial genetic structure in grazed populations of Dianthus carthusianorum.

Science.gov (United States)

Rico, Y; Wagner, H H

2016-11-01

Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on rates of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep grazing on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep grazing showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of grazing treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep grazing were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep grazing has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep grazing to importantly reduce genetic structure at local scales within restored plant populations.

Rotator cuff tear reduces muscle fiber specific force production and induces macrophage accumulation and autophagy.

Science.gov (United States)

Gumucio, Jonathan P; Davis, Max E; Bradley, Joshua R; Stafford, Patrick L; Schiffman, Corey J; Lynch, Evan B; Claflin, Dennis R; Bedi, Asheesh; Mendias, Christopher L

2012-12-01

Full-thickness tears to the rotator cuff can cause severe pain and disability. Untreated tears progress in size and are associated with muscle atrophy and an infiltration of fat to the area, a condition known as "fatty degeneration." To improve the treatment of rotator cuff tears, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential. Using a rat model of rotator cuff injury, we measured the force generating capacity of individual muscle fibers and determined changes in muscle fiber type distribution that develop after a full thickness rotator cuff tear. We also measured the expression of mRNA and miRNA transcripts involved in muscle atrophy, lipid accumulation, and matrix synthesis. We hypothesized that a decrease in specific force of rotator cuff muscle fibers, an accumulation of type IIb fibers, and an upregulation in fibrogenic, adipogenic, and inflammatory gene expression occur in torn rotator cuff muscles. Thirty days following rotator cuff tear, we observed a reduction in muscle fiber force production, an induction of fibrogenic, adipogenic, and autophagocytic mRNA and miRNA molecules, and a dramatic accumulation of macrophages in areas of fat accumulation. Copyright © 2012 Orthopaedic Research Society.

Conversion from cropland to short rotation coppice willow and poplar: Accumulation of soil organic carbon

Science.gov (United States)

Georgiadis, Petros; Stupak, Inge; Vesterdal, Lars; Raulund-Rasmussen, Karsten

2015-04-01

Increased demand for bioenergy has intensified the production of Short Rotation Coppice (SRC) willow and poplar in temperate zones. We used a combined chronosequence and paired plot approach to study the potential of SRC willow and poplar stands to increase the soil carbon stock compared to stocks of the previous arable land-use. The study focused on well-drained soils. We sampled soil from 30 SRC stands in Denmark and southern Sweden including soils from their adjacent arable fields. The 18 willow and 12 poplar stands formed a chronosequence ranging between 4 and 29 years after conversion. The soil was sampled both with soil cores taken by fixed depths of 0-5, 5-10, 10-15, 15-25, and 25-40 cm and by genetic horizons from soil pits to 1m depth. The aim of the study was to estimate the difference and the ratio between soil carbon contents of the SRC and annual crop land and analyze the results as a chronosequence to examine the effect of age after conversion on the difference. Covariates such as soil type, fertilization type and harvest frequency were also taken into account. Preliminary results suggest an overall increase in carbon stocks over time with average accumulation rates ranging from 0.25 to 0.4 Mg ha-1 yr-1 in willow and poplar stands. Poplar stands had higher rates of C gain, probably due to less frequent harvesting. The differences in carbon between the SRC and the paired cropland were initially negative but changed to positive over time, implying loss of carbon after conversion and a later gain in soil carbon with stand age. Pairwise differences ranged from -25 Mg C ha-1 to 37 Mg C ha-1 for the top 40 cm. The carbon stock ratio of the SRC stand to the arable land was estimated to minimize the effect of site-related factors. The results of this analysis suggested that the ratio increased significantly with age after conversion for the top 10 cm of the soil, both for poplar and willow. A slight increase with age was also noticed at the deeper depths, but

Non-energy markets for small roundwood, forest residues and short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Watt, G.

1995-06-01

Competition for roundwood is intense at the present time with prices ranging from approximately Pound 20 to Pound 51 per green tonne delivered at mill. The sawmilling industry produces nearly 2 million green tonnes of residues annually from converting British roundwood and about 85% of this is used by the panelboard and paperboard mills. The remaining 15%, comprising mostly bark, and some of the unpeeled chips are used as material for mulching, landscaping and horticultural use, play areas, paths and horse gallops, soil composting and soil conditioning. Wood shavings and sawdust is produced by joinery and milling firms from imported sawn timber and amounts to about 300,000 tonnes/annum. Approximately 70% of this is used for higher priced markets, bedding for horses, chicken and turkeys, cattle and other uses. The remaining 30% is used in the wood processing industry. An increasing volume of solid wood waste which previously went for landfill sites is now being recycled and this trend is expected to continue. Only a very small proportion of the forest residues (tree tops and branches) produced each year is utilised and most of this material is used as mulch for horticultural and landscape uses. Markets for material from traditional short rotation coppice are limited relative to potential production but work is underway to develop new markets. There are no established markets for recently planted non-traditional coppice of willow and poplar with potential for energy production. Trials organised by ETSU and the DTI have indicated the suitability of the material for chipboard production provided the bark percentage is not too high. (author)

Non-energy markets for small roundwood, forest residues and short rotation coppice

International Nuclear Information System (INIS)

Watt, G.

1995-01-01

Competition for roundwood is intense at the present time with prices ranging from approximately Pound 20 to Pound 51 per green tonne delivered at mill. The sawmilling industry produces nearly 2 million green tonnes of residues annually from converting British roundwood and about 85% of this is used by the panelboard and paperboard mills. The remaining 15%, comprising mostly bark, and some of the unpeeled chips are used as material for mulching, landscaping and horticultural use, play areas, paths and horse gallops, soil composting and soil conditioning. Wood shavings and sawdust is produced by joinery and milling firms from imported sawn timber and amounts to about 300,000 tonnes/annum. Approximately 70% of this is used for higher priced markets, bedding for horses, chicken and turkeys, cattle and other uses. The remaining 30% is used in the wood processing industry. An increasing volume of solid wood waste which previously went for landfill sites is now being recycled and this trend is expected to continue. Only a very small proportion of the forest residues (tree tops and branches) produced each year is utilised and most of this material is used as mulch for horticultural and landscape uses. Markets for material from traditional short rotation coppice are limited relative to potential production but work is underway to develop new markets. There are no established markets for recently planted non-traditional coppice of willow and poplar with potential for energy production. Trials organised by ETSU and the DTI have indicated the suitability of the material for chipboard production provided the bark percentage is not too high. (author)

Comparison of Short vs Long Anti-rotation in Treating Trochanteric Fractures

Directory of Open Access Journals (Sweden)

Raval P

2016-03-01

Full Text Available Introduction: A comparative evaluation of the surgical treatment and outcome of patients with pertrochanteric fractures treated with short versus long proximal femoral nail antirotation. Materials and methods: A retrospective review was conducted of patients with pertrochanteric fractures treated between January 2011 and June 2012. In all 80 patients were enrolled in the study, of which 40 were treated with short PFNA and the remaining with long PFNA. Comparative analyses of demographic data, peri-operative outcome and complications were carried out. Results: There was no significant difference noted in the two groups with regards to Arbeitsgemeinschaft fur Osteosynthesefragen (AO fracture classification, time from injury to surgery, blood transfusion post surgery and hospital stay. The surgical duration for a short PFNA procedure was significantly less (58 minutes when compared to that of a long PFNA (87 minutes. Similarly intra-operative blood loss was significantly higher in the long PFNA group as compared to the short PFNA. Conclusions: A relatively quicker surgical time of just under an hour , lesser blood loss and better learning curve with trainee surgeons make short PFNA a better implant choice in the treatment of pertrochanteric fractures.

Laser Doppler vibrometry on rotating structures in coast-down: resonance frequencies and operational deflection shape characterization

International Nuclear Information System (INIS)

Martarelli, M; Castellini, P; Santolini, C; Tomasini, E P

2011-01-01

In rotating machinery, variations of modal parameters with rotation speed may be extremely important in particular for very light and undamped structures, such as helicopter rotors or wind turbines. The natural frequency dependence on rotation speed is conventionally measured by varying the rotor velocity and plotting natural frequencies versus speed in the so-called Campbell diagram. However, this kind of analysis does not give any information about the vibration spatial distribution i.e. the mode shape variation with the rotation speed must be investigated with dedicated procedures. In several cases it is not possible to fully control the rotating speed of the machine and only coast-down tests can be performed. Due to the reduced inertia of rotors, the coast-down process is usually an abrupt transient and therefore an experimental technique, able to determine operational deflection shapes (ODSs) in short time, with high spatial density and accuracy, appears very promising. Moreover coast-down processes are very difficult to control, causing unsteady vibrations. Hence, a very efficient approach for the rotation control and synchronous acquisition must be developed. In this paper a continuous scanning system able to measure ODSs and natural frequencies excited during rotor coast-down is shown. The method is based on a laser Doppler vibrometer (LDV) whose laser beam is driven to scan continuously over the rotor surface, in order to measure the ODS, and to follow the rotation of the rotor itself even in coast-down. With a single measurement the ODSs can be recovered from the LDV output time history in short time and with huge data saving. This technique has been tested on a laboratory test bench, i.e. a rotating two-blade fan, and compared with a series of non-contact approaches based on LDV: - traditional experimental modal analysis (EMA) results obtained under non-rotating conditions by measuring on a sequence of points on the blade surface excited by an impact

Increasing age and tear size reduce rotator cuff repair healing rate at 1 year.

Science.gov (United States)

Rashid, Mustafa S; Cooper, Cushla; Cook, Jonathan; Cooper, David; Dakin, Stephanie G; Snelling, Sarah; Carr, Andrew J

2017-12-01

Background and purpose - There is a need to understand the reasons why a high proportion of rotator cuff repairs fail to heal. Using data from a large randomized clinical trial, we evaluated age and tear size as risk factors for failure of rotator cuff repair. Patients and methods - Between 2007 and 2014, 65 surgeons from 47 hospitals in the National Health Service (NHS) recruited 447 patients with atraumatic rotator cuff tendon tears to the United Kingdom Rotator Cuff Trial (UKUFF) and 256 underwent rotator cuff repair. Cuff integrity was assessed by imaging in 217 patients, at 12 months post-operation. Logistic regression analysis was used to determine the influence of age and intra-operative tear size on healing. Hand dominance, sex, and previous steroid injections were controlled for. Results - The overall healing rate was 122/217 (56%) at 12 months. Healing rate decreased with increasing tear size (small tears 66%, medium tears 68%, large tears 47%, and massive tears 27% healed). The mean age of patients with a healed repair was 61 years compared with 64 years for those with a non-healed repair. Mean age increased with larger tear sizes (small tears 59 years, medium tears 62 years, large tears 64 years, and massive tears 66 years). Increasing age was an independent factor that negatively influenced healing, even after controlling for tear size. Only massive tears were an independent predictor of non-healing, after controlling for age. Interpretation - Although increasing age and larger tear size are both risks for failure of rotator cuff repair healing, age is the dominant risk factor.

Dynamics of Tidally Locked, Ultrafast Rotating Atmospheres

Science.gov (United States)

Tan, Xianyu; Showman, Adam P.

2017-10-01

Tidally locked gas giants, which exhibit a novel regime of day-night thermal forcing and extreme stellar irradiation, are typically in several-day orbits, implying slow rotation and a modest role for rotation in the atmospheric circulation. Nevertheless, there exist a class of gas-giant, highly irradiated objects - brown dwarfs orbiting white dwarfs in extremely tight orbits - whose orbital and hence rotation periods are as short as 1-2 hours. Spitzer phase curves and other observations have already been obtained for this fascinating class of objects, which raise fundamental questions about the role of rotation in controlling the circulation. So far, most modeling studies have investigated rotation periods exceeding a day, as appropriate for typical hot Jupiters. In this work we investigate the dynamics of tidally locked atmospheres in shorter rotation periods down to about two hours. With increasing rotation rate (decreasing rotation period), we show that the width of the equatorial eastward jet decreases, consistent with the narrowing of wave-mean-flow interacting region due to decrease of the equatorial deformation radius. The eastward-shifted equatorial hot spot offset decreases accordingly, and the westward-shifted hot regions poleward of the equatorial jet associated with Rossby gyres become increasingly distinctive. At high latitudes, winds becomes weaker and more geostrophic. The day-night temperature contrast becomes larger due to the stronger influence of rotation. Our simulated atmospheres exhibit small-scale variability, presumably caused by shear instability. Unlike typical hot Jupiters, phase curves of fast-rotating models show an alignment of peak flux to secondary eclipse. Our results have important implications for phase curve observations of brown dwarfs orbiting white dwarfs in ultra tight orbits.

Oscillatory-rotational processes in the Earth motion about the center of mass: Interpolation and forecast

Science.gov (United States)

Akulenko, L. D.; Klimov, D. M.; Markov, Yu. G.; Perepelkin, V. V.

2012-11-01

The celestial-mechanics approach (the spatial version of the problem for the Earth-Moon system in the field of gravity of the Sun) is used to construct a mathematical model of the Earth's rotational-oscillatory motions. The fundamental aspects of the processes of tidal inhomogeneity in the Earth rotation and the Earth's pole oscillations are studied. It is shown that the presence of the perturbing component of gravitational-tidal forces, which is orthogonal to the Moon's orbit plane, also allows one to distinguish short-period perturbations in the Moon's motion. The obtained model of rotational-oscillatory motions of the nonrigid Earth takes into account both the basic perturbations of large amplitudes and the more complicated small-scale properties of the motion due to the Moon short-period perturbations with combination frequencies. The astrometric data of the International Earth Rotation and Reference Systems Service (IERS) are used to perform numerical simulation (interpolation and forecast) of the Earth rotation parameters (ERP) on various time intervals.

Sewage sludge and wastewater fertilisation of Short Rotation Coppice (SRC) for increased bioenergy production - Biological and economic potential

International Nuclear Information System (INIS)

Dimitriou, I.; Rosenqvist, H.

2011-01-01

Application of municipal residues, e.g. wastewater or sewage sludge, to Short Rotation Coppice (SRC) is among the most attractive methods for attaining environmental and energy goals set for Europe. At current woodchip prices in Sweden, the gross margin for SRC cultivation is positive only if biomass production is >9 t DM/ha yr. The gross profit margin increases (by 39 and 199 EUR/GJ, respectively) if sewage sludge and wastewater are applied to SRC. Application of residues to SRC has proved to be an acceptable alternative treatment method, and the farmer's profit can be markedly increased if compensation is paid for waste treatment. If all available sludge and wastewater were applied to SRC plantations, they could be grown on large agricultural areas in Europe, and c. 6000 PJ of renewable energy could be produced annually. However, a more economical landuse strategy, e.g. the use of more P-rich residues, appears more rational, and is biologically justifiable. (author)

Sewage sludge and wastewater fertilisation of Short Rotation Coppice (SRC) for increased bioenergy production - Biological and economic potential

Energy Technology Data Exchange (ETDEWEB)

Dimitriou, I. [Department of Crop Production Ecology, Swedish University of Agricultural Sciences, P.O. Box 7043, SE 750 07 Uppsala (Sweden); Rosenqvist, H. [Department of Agriculture-Farming Systems, Technology and Product Quality, Swedish University of Agricultural Sciences, P.O. Box 17, SE-261 21 Billeberga (Sweden)

2011-02-15

Application of municipal residues, e.g. wastewater or sewage sludge, to Short Rotation Coppice (SRC) is among the most attractive methods for attaining environmental and energy goals set for Europe. At current woodchip prices in Sweden, the gross margin for SRC cultivation is positive only if biomass production is >9 t DM/ha yr. The gross profit margin increases (by 39 and 199 EUR/GJ, respectively) if sewage sludge and wastewater are applied to SRC. Application of residues to SRC has proved to be an acceptable alternative treatment method, and the farmer's profit can be markedly increased if compensation is paid for waste treatment. If all available sludge and wastewater were applied to SRC plantations, they could be grown on large agricultural areas in Europe, and c. 6000 PJ of renewable energy could be produced annually. However, a more economical landuse strategy, e.g. the use of more P-rich residues, appears more rational, and is biologically justifiable. (author)

Teduglutide reduces need for parenteral support among patients with short bowel syndrome with intestinal failure

DEFF Research Database (Denmark)

Jeppesen, Palle B; Pertkiewicz, Marek; Messing, Bernard

2012-01-01

Teduglutide, a glucagon-like peptide 2 analogue, might restore intestinal structural and functional integrity by promoting growth of the mucosa and reducing gastric emptying and secretion. These factors could increase fluid and nutrient absorption in patients with short bowel syndrome with intest...

Changes in bird community composition in response to growth changes in short-rotation woody crop planting

International Nuclear Information System (INIS)

Tolbert, V.R.; Hanowski, J.; Schiller, A.; Hoffman, W.; Christian, D.; Lindberg, J.

1997-01-01

Hybrid poplar established as intensively managed short-rotation woody crops (SRWC) on former agricultural lands can provide habitat for wildlife. Studies of bird use of SRWC for nesting and during fall migration have shown that the numbers and kinds of breeding birds using mature plantings of hybrid poplar are similar to natural forested lands. In Minnesota, the number of species of breeding birds using habitat provided by clonal-trial plantings and young larger-scale plantings (12-64 ha) of hybrid poplar were initially most similar to those using grasslands and row-crops. As the plantings approached canopy closure, successional species became predominant. In the Pacific Northwest, breeding bird composition and density were very similar for mature plantings and forested areas; however, fall migrants were found primarily in forested areas. In the Southeast, preliminary comparisons of breeding bird use of plantings of sweetgum and sycamore with naturally regenerating forests of different ages and sizes and vegetation structure are showing no size effect on use. As with hybrid poplar, species use of the more mature plantings of sweetgum and sycamore was most similar to that of natural forests. (author)

Developing an Asteroid Rotational Theory

Science.gov (United States)

Geis, Gena; Williams, Miguel; Linder, Tyler; Pakey, Donald

2018-01-01

The goal of this project is to develop a theoretical asteroid rotational theory from first principles. Starting at first principles provides a firm foundation for computer simulations which can be used to analyze multiple variables at once such as size, rotation period, tensile strength, and density. The initial theory will be presented along with early models of applying the theory to the asteroid population. Early results confirm previous work by Pravec et al. (2002) that show the majority of the asteroids larger than 200m have negligible tensile strength and have spin rates close to their critical breakup point. Additionally, results show that an object with zero tensile strength has a maximum rotational rate determined by the object’s density, not size. Therefore, an iron asteroid with a density of 8000 kg/m^3 would have a minimum spin period of 1.16h if the only forces were gravitational and centrifugal. The short-term goal is to include material forces in the simulations to determine what tensile strength will allow the high spin rates of asteroids smaller than 150m.

Potential benefits of commercial willow Short Rotation Coppice (SRC) for farm-scale plant and invertebrate communities in the agri-environment

Energy Technology Data Exchange (ETDEWEB)

Rowe, Rebecca L.; Hanley, Mick E.; Goulson, Dave; Clarke, Donna J.; Doncaster, C. Patrick; Taylor, Gail [University of Southampton, Faculty of Natural and Environmental Sciences, Life Sciences Building, Southampton, S017 1BJ (United Kingdom)

2011-01-15

The cultivation of bioenergy crops (BECs) represents a significant land-use change in agri-environments, but their deployment has raised important issues globally regarding possible impacts on biodiversity. Few studies however, have systematically examined the effect of commercial scale bioenergy plantations on biodiversity in agri-ecosystems. In this study we investigate how the abundance and diversity of two key components of farmland biodiversity (ground flora and winged invertebrates) varied between mature willow Short Rotation Coppice (SRC) and two alternative land-use options (arable crops and set-aside land). Although the abundance of winged invertebrates was similar across all land-uses, taxonomic composition varied markedly. Hymenoptera and large Hemiptera (>5 mm) were more abundant in willow SRC than in arable or set-aside. Similarly although plant species richness was greater in set-aside, our data show that willow SRC supports a different plant community to the other land-uses, being dominated by competitive perennial species such as Elytrigia repens and Urtica dioica. Our results suggest that under current management practices a mixed farming system incorporating willow SRC can benefit native farm-scale biodiversity. In particular the reduced disturbance in willow SRC allows the persistence of perennial plant species, potentially providing a stable refuge and food sources for invertebrates. In addition, increased Hymenoptera abundance in willow SRC could potentially have concomitant effects on ecosystem processes, as many members of this Order are important pollinators of crop plants or otherwise fulfil an important beneficial role as predators or parasites of crop pests. (author)

The Potential for Forestry to Reduce Net CO2 Emissions

International Nuclear Information System (INIS)

Eriksson, Erik

2006-01-01

Forestry may have an important role to play in attempts to reduce atmospheric CO 2 levels, since countries may choose to account for forest management activities to fulfil their commitments under the Kyoto Protocol. However, the effectiveness of such efforts may depend on the forest management strategies applied. This thesis is based on four separate studies in which the potential for forest management strategies to decrease net CO 2 emissions was considered. Long-term field experiments and models were used to: evaluate the impact of different thinning regimes; study broad-leaved stands growing on abandoned farmland with different rotation lengths; predict the effects of using different rotation lengths on carbon accumulation and fossil fuel substitution; and perform an integrated analysis of forest management practices and the potential to substitute fossil fuels by wood products. To evaluate the effects of the management regimes considered, carbon stocks in the investigated stands and the potential of the resulting biomass to substitute fossil fuel were estimated. No significant differences were found in biomass production between the thinning regimes for Norway spruce (Picea abies (L.) Karst.) stands, but the standing biomass was significantly larger in unthinned stands, indicating that to maximize the carbon stock in tree biomass thinnings should be avoided. For Scots pine (Pinus sylvestris L.), thinned and fertilized stands produced significantly more biomass (2.60-2.72 ton d.w./ha/yr) than unthinned and unfertilized stands (2.17-2.34 ton d.w./ha/yr) in the northern regions. These findings indicate that fertilization might be a viable measure to increase production of biomass with the potential to replace fossil fuel and energy-intensive material. In addition, for broad-leaved trees stands on abandoned farmland, management regimes with a short rotation were found to be better for maximizing the substitution of fossil fuel than regimes with a long rotation

THE DISCOVERY OF DIFFERENTIAL RADIAL ROTATION IN THE PULSATING SUBDWARF B STAR KIC 3527751

Energy Technology Data Exchange (ETDEWEB)

Foster, H. M.; Reed, M. D. [Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, MO 65897 (United States); Telting, J. H. [Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breña Baja (Spain); Østensen, R. H. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Baran, A. S. [Uniwersytet Pedagogiczny, Obserwatorium na Suhorze, ul. Podchorażych 2, 30-084 Kraków (Poland)

2015-06-01

We analyze 3 yr of nearly continuous Kepler spacecraft short cadence observations of the pulsating subdwarf B (sdB) star KIC 3527751. We detect a total of 251 periodicities, most in the g-mode domain, but some where p-modes occur, confirming that KIC 3527751 is a hybrid pulsator. We apply seismic tools to the periodicities to characterize the properties of KIC 3527751. Techniques to identify modes include asymptotic period spacing relationships, frequency multiplets, and the separation of multiplet splittings. These techniques allow for 189 (75%) of the 251 periods to be associated with pulsation modes. Included in these are three sets of ℓ = 4 multiplets and possibly an ℓ = 9 multiplet. Period spacing sequences indicate ℓ = 1 and 2 overtone spacings of 266.4 ± 0.2 and 153.2 ± 0.2 s, respectively. We also calculate reduced periods, from which we find evidence of trapped pulsations. Such mode trappings can be used to constrain the core/atmosphere transition layers. Interestingly, frequency multiplets in the g-mode region, which sample deep into the star, indicate a rotation period of 42.6 ± 3.4 days while p-mode multiplets, which sample the outer envelope, indicate a rotation period of 15.3 ± 0.7 days. We interpret this as differential rotation in the radial direction with the core rotating more slowly. This is the first example of differential rotation for a sdB star.

Electromagnetic solitary vortices in rotating plasma

International Nuclear Information System (INIS)

Liu, J.; Horton, W.

1985-12-01

The nonlinear equations describing drift-Alfven solitary vortices in a low β, rotating plasma are derived. Two types of solitary vortex solutions along with their corresponding nonlinear dispersion relations are obtained. Both solutions have the localized coherent dilopar structure. The first type of solution belongs to the family of the usual Rossby or drift wave vortex, while the second type of solution is intrinsic to the electromagnetic perturbation in a magnetized plasma and is a complicated structure. While the first type of vortex is a solution to a second order differential equation the second one is the solution of a fourth order differential equation intrinsic to the electromagnetic problem. The fourth order vortex solution has two intrinsic space scales in contrast to the single space scale of the previous drift vortex solution. With the second short scale length the parallel current density at the vortex interface becomes continuous. As special cases the rotational electron drift vortex and the rotational ballooning vortex also are given. 10 refs

On LAM's and SAM's for Halley's rotation

Science.gov (United States)

Peale, Stanton J.

1992-01-01

Non principal axis rotation for comet Halley is inferred from dual periodicities evident in the observations. The modes where the spin axis precesses around the axis of minimum moment of inertia (long axis mode or LAM) and where it precesses around the axis of maximum moment of inertia (short axis mode or SAM) are described from an inertial point of view. The currently favored LAM model for Halley's rotation state satisfies observational and dynamical constraints that apparently no SAM can satisfy. But it cannot reproduce the observed post perihelion brightening through seasonal illumination of localized sources on the nucleus, whereas a SAM can easily produce post or pre perihelion brightening by this mechanism. However, the likelihood of a LAM rotation for elongated nuclei of periodic comets such as Halley together with Halley's extreme post perihelion behavior far from the Sun suggest that Halley's post perihelion brightening may be due to effects other than seasonal illumination of localized sources, and therefore such brightening may not constrain its rotation state.

Eucalyptus and Populus short rotation woody crops for phosphate mined lands in Florida USA

Energy Technology Data Exchange (ETDEWEB)

Rockwood, D L; Carter, D R; Langholtz, M H [The School of Forest Resources and Conservation, University of Florida, Box 110410, Gainesville, FL 32611 0410 (United States); Stricker, J A [Polk County Extension Service, University of Florida, Gainesville, FL 32611 (United States)

2006-08-15

Our short-rotation woody crops (SRWC) research in central and southern Florida is (1) developing superior Eucalyptus grandis (EG), E. amplifolia (EA), and cottonwood (Populus deltoides, PD) genotypes, (2) determining appropriate management practices for and associated productivities of these genotypes, and (3) assessing their economics and markets. Reclaimed clay settling areas (CSA) and overburden sites in phosphate mined areas in central Florida are a potential land base of over 80,000ha for SRWC production. On CSAs, PD grows well in the absence of cogongrass (Imperata cylindrica) but is not as productive as the non-invasive EG and EA. SRWC establishment on CSAs requires strict implementation of the following cultural practices: thorough site preparation through herbiciding/disking and bedding, superior trees, watering/packing seedlings, fertilization with ammonium nitrate at planting and annually thereafter as feasible, high planting density possibly including double row planting, and winter harvesting so that coppice regeneration suppresses weeds. PD cultural requirements, that may require post-planting weed control to suppress herbaceous competition, exceed those of the eucalypts. EG SRWCs on CSAs are at risk of blowdown 3-4 years after planting or coppicing; younger PD, EG, and EA SRWCs appear much less susceptible to wind damage. Genetic improvement must continue if EG, EA, and PD are to increase in commercial feasibility. SRWC cost competitiveness will depend on establishment success, yield improvements, harvesting costs, and identifying/using incentives. Strong collaboration among public and private partners is necessary for commercializing SRWCs in Florida. (author)

Rotational inertia of continents: A proposed link between polar wandering and plate tectonics

Science.gov (United States)

Kane, M.F.

1972-01-01

A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.

ROTATIONAL SYNCHRONIZATION MAY ENHANCE HABITABILITY FOR CIRCUMBINARY PLANETS: KEPLER BINARY CASE STUDIES

International Nuclear Information System (INIS)

Mason, Paul A.; Zuluaga, Jorge I.; Cuartas-Restrepo, Pablo A.; Clark, Joni M.

2013-01-01

We report a mechanism capable of reducing (or increasing) stellar activity in binary stars, thereby potentially enhancing (or destroying) circumbinary habitability. In single stars, stellar aggression toward planetary atmospheres causes mass-loss, which is especially detrimental for late-type stars, because habitable zones are very close and activity is long lasting. In binaries, tidal rotational breaking reduces magnetic activity, thus reducing harmful levels of X-ray and ultraviolet (XUV) radiation and stellar mass-loss that are able to erode planetary atmospheres. We study this mechanism for all confirmed circumbinary (p-type) planets. We find that main sequence twins provide minimal flux variation and in some cases improved environments if the stars rotationally synchronize within the first Gyr. Solar-like twins, like Kepler 34 and Kepler 35, provide low habitable zone XUV fluxes and stellar wind pressures. These wide, moist, habitable zones may potentially support multiple habitable planets. Solar-type stars with lower mass companions, like Kepler 47, allow for protected planets over a wide range of secondary masses and binary periods. Kepler 38 and related binaries are marginal cases. Kepler 64 and analogs have dramatically reduced stellar aggression due to synchronization of the primary, but are limited by the short lifetime. Kepler 16 appears to be inhospitable to planets due to extreme XUV flux. These results have important implications for estimates of the number of stellar systems containing habitable planets in the Galaxy and allow for the selection of binaries suitable for follow-up searches for habitable planets

ROTATIONAL SYNCHRONIZATION MAY ENHANCE HABITABILITY FOR CIRCUMBINARY PLANETS: KEPLER BINARY CASE STUDIES

Energy Technology Data Exchange (ETDEWEB)

Mason, Paul A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Zuluaga, Jorge I.; Cuartas-Restrepo, Pablo A. [FACom-Instituto de Fisica-FCEN, Universidad de Antioquia, Calle 70 No. 52-21, Medellin (Colombia); Clark, Joni M. [Department of Mathematics and Physical Sciences, New Mexico State University-DACC, Las Cruces, NM 88003 (United States)

2013-09-10

We report a mechanism capable of reducing (or increasing) stellar activity in binary stars, thereby potentially enhancing (or destroying) circumbinary habitability. In single stars, stellar aggression toward planetary atmospheres causes mass-loss, which is especially detrimental for late-type stars, because habitable zones are very close and activity is long lasting. In binaries, tidal rotational breaking reduces magnetic activity, thus reducing harmful levels of X-ray and ultraviolet (XUV) radiation and stellar mass-loss that are able to erode planetary atmospheres. We study this mechanism for all confirmed circumbinary (p-type) planets. We find that main sequence twins provide minimal flux variation and in some cases improved environments if the stars rotationally synchronize within the first Gyr. Solar-like twins, like Kepler 34 and Kepler 35, provide low habitable zone XUV fluxes and stellar wind pressures. These wide, moist, habitable zones may potentially support multiple habitable planets. Solar-type stars with lower mass companions, like Kepler 47, allow for protected planets over a wide range of secondary masses and binary periods. Kepler 38 and related binaries are marginal cases. Kepler 64 and analogs have dramatically reduced stellar aggression due to synchronization of the primary, but are limited by the short lifetime. Kepler 16 appears to be inhospitable to planets due to extreme XUV flux. These results have important implications for estimates of the number of stellar systems containing habitable planets in the Galaxy and allow for the selection of binaries suitable for follow-up searches for habitable planets.

Short-term exercise reduces markers of hepatocyte apoptosis in nonalcoholic fatty liver disease

DEFF Research Database (Denmark)

Fealy, Ciaran E; Haus, Jacob M; Solomon, Thomas

2012-01-01

and after the exercise intervention. The Matsuda index was used to assess insulin sensitivity. We observed significant decreases in CK18 fragments (558.4 ± 106.8 vs. 323.4 ± 72.5 U/l, P vs. 24.3 ± 4.8 U/l, P vs. 69...... changes in fat oxidation and circulating sFasL (rho = -0.65, P vs. 17.5 ± 2.1%, NS). We conclude that short-term exercise reduces a circulatory marker of hepatocyte apoptosis in obese individuals with NAFLD and propose that changes....... We therefore examined the effect of a short-term exercise program on markers of apoptosis-plasma cytokeratin 18 (CK18) fragments, alanine aminotransferase (ALT), aspartate aminotransferase (AST), soluble Fas (sFas), and sFas ligand (sFasL)-in 13 obese individuals with NAFLD [body mass index 35.2 ± 1...

Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades

Science.gov (United States)

Howard, Samuel A.; Hammer, Jeremiah T.; Carney, Kelly S.; Pereira, J. Michael

2013-01-01

Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990 to 2007 in the US alone (Ref. 1). As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a nonrotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests. NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the prestress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in

SUN-LIKE MAGNETIC CYCLES IN THE RAPIDLY ROTATING YOUNG SOLAR ANALOG HD 30495

International Nuclear Information System (INIS)

Egeland, Ricky; Metcalfe, Travis S.; Hall, Jeffrey C.; Henry, Gregory W.

2015-01-01

A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (∼2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, a ∼1 Gyr old G1.5 V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at ∼1.7 years and a long cycle of ∼12 years. We measure three individual long-period cycles and find durations ranging from 9.6 to 15.5 years. We find the short-term variability to be intermittent, but present throughout the majority of the time series, though its occurrence and amplitude are uncorrelated with the longer cycle. These essentially solar-like variations occur in a Sun-like star with more rapid rotation, though surface differential rotation measurements leave open the possibility of a solar equivalence

Assessing the Influence of Summer Organic Fertilization Combined with Nitrogen Inhibitor on a Short Rotation Woody Crop in Mediterranean Environment

Directory of Open Access Journals (Sweden)

Anita Maienza

2014-01-01

Full Text Available The European Union Directive 91/676/EEC, known as Nitrates Directive, has dictated basic agronomic principles regarding the use of animal manure source as well as livestock and waste waters from small food companies. The use of nitrification inhibitors together with animal effluents as organic fertilizers could be beneficial for nutrient recycling, plant productivity, and greenhouse gas emission and could offer economic advantages as alternative to conventional fertilizers especially in the Mediterranean region. The aim of the present study was to investigate differences in plant productivity between bovine effluent treatments with (or without addition of a nitrification inhibitor (3,4 DMPP in a short rotation woody crop system. Results of the field experiment carried out in a Mediterranean dry environment indicated that the proposed strategy could improve tree growth with indirect, beneficial effects for agroforestry systems.

Reducing Postoperative Pterygium Recurrence: Comparison of Free Conjunctival Auto-Graft and Conjunctival Rotation Flap Techniques

International Nuclear Information System (INIS)

Akhter, W.; Tayyab, A.; Kausar, A.; Masrur, A.

2014-01-01

Objective: To compare the recurrence of pterygium between free conjunctival auto-graft and conjunctival rotation flap following simple surgical excision of pterygium. Study Design: Quasi-experimental study. Place and Duration of Study: Shifa Foundation Community Health Clinic, Shifa College of Medicine, Islamabad, from January to November 2012. Methodology: Fifty seven cases aged above 18 years, with a pterygium corneal encroachment of 2 mm which was responsible for visual disability or was cosmetically undesirable were recruited for the study and randomly assigned to conjunctival auto-graft group and conjunctival rotation flap group. Cases with a history of glaucoma or glaucoma suspect, prior pterygium surgery, pterygium with concurrent ocular surface and lid disease, conjunctival inflammation and scarring, pseudo-pterygium or collagen vascular disease were excluded. After simple pterygium excision conjunctival auto-graft group (n=26) cases received a free conjunctival flap was transplanted, while conjunctival rotation flap group (n=31) cases received a conjunctival rotation flap. All cases were followed-up for 6 months after surgery for recurrence and complications. Frequency distribution and significance of association of recurrence using Fisher's exact test and Mann- Whitney U-test was carried out using Statistical Package for Social Sciences (SPSS) version 20. Results: The median (and inter-quartile range) age and surgery duration in conjunctival auto-graft group and conjunctival rotation flap group were 60 (51.50 - 63.00) and 57 (45.00 - 60.00) years, 28.50 (27.00 - 30.50) and 16.00 (15.00 - 17.00) minutes respectively. Recurrence was seen in 2 (7.96%) and 3 (9.76%) cases in auto-graft and rotation flap groups respectively. No significant difference was seen in postoperative complications between the two groups (p=0.60). Conclusion: The surgical time for conjunctival rotation flap procedure is less as compared to free auto-graft, while their recurrence and

Anabolic Steroids Reduce Muscle Degeneration Associated With Rotator Cuff Tendon Release in Sheep.

Science.gov (United States)

Gerber, Christian; Meyer, Dominik C; Flück, Martin; Benn, Mario C; von Rechenberg, Brigitte; Wieser, Karl

2015-10-01

Chronic rotator cuff tendon tearing is associated with irreversible atrophy, fatty infiltration, and interstitial fibrosis of the corresponding muscle. Anabolic steroids can prevent musculotendinous degeneration during retraction and/or can reverse these changes after operative repair of the retracted musculotendinous unit in sheep. Controlled laboratory study. The infraspinatus tendon was released in 18 alpine sheep. All sheep underwent repair of the retracted musculotendinous unit after 16 weeks and were sacrificed after 22 weeks; 6 sheep served as controls, 6 sheep were treated with weekly intramuscular injection of 150 mg of nandrolone decanoate after infraspinatus (ISP) repair (group N6W), and 6 sheep were treated with 150 mg of nandrolone decanoate immediately after tendon release (group N22W). Muscle biopsy specimens were taken before tendon release and after 16 and 22 weeks. Muscle volume and fatty infiltration (on MRI), myotendinous retraction, and muscle density (on computed tomography) were measured immediately after ISP release, after 6 weeks, and before ISP repair and sacrifice. Muscle volume on MRI decreased to a mean (±SD) of 80% ± 8% of the original volume after 6 weeks, remained stable at 78% ± 11% after 16 weeks, and decreased further to 69% ± 9% after 22 weeks in the control group. These findings were no different from those in group N22W (72% ± 9% at 6 weeks, 73% ± 6% at 16 weeks, and 67% ± 5% at 22 weeks). Conversely, the N6W group did not show a decrease in ISP volume after repair; this finding differed significantly from the response in the control and N22W groups. Fatty infiltration (on MRI) continuously increased in the control group (12% ± 4% at tendon release, 17% ± 4% after 6 weeks, 50% ± 9% after 16 weeks, and 60% ± 8% after 22 weeks) and the N6W group. However, application of anabolic steroids at the time of tendon release (N22W group) significantly reduced fatty infiltration after 16 (16% ± 5%; P anabolic steroids starting

Are intra-articular corticosteroid injections better than conventional TENS in treatment of rotator cuff tendinitis in the short run? A randomized study.

Science.gov (United States)

Eyigor, C; Eyigor, S; Kivilcim Korkmaz, O

2010-09-01

Rotator cuff problems are common causes of pain and restriction of movement in shoulder. The aim of this study to compare the effect of intra-articular injection of corticosteroid and conventional transcutaneous electrical nerve stimulator (TENS) treatment in treatment of rotator cuff tendinitis. Subjects were randomly allocated into Group 1 (intra-articular injection of corticosteroid) and Group 2 (conventional transcutaneous electrical nerve stimulation-TENS). Outcome measurements were performed using the Visual Analogue Scale (VAS) for pain, range of motion (ROM), the Shoulder Disability Questionnaire (SDQ), the Short Form-36 (SF-36), and Beck Depression Scale (BDS) questionnaires and paracetamol consumption. In both groups, significant improvement was observed in all weeks in VAS, ROM and SDQ scores (P0.05). In both treatment groups, paracetamol consumption decreased in time (Protator cuff tendinitis. When two treatments are compared, it may be concluded that intra-articular steroid injection was more effective especially in the first weeks regarding pain, ROM and disability. Otherwise, use of TENS allow to patients to increase activity level, improve function and quality of life like that in our study. TENS, as it is cheaper, non-invasive, more easily performed and efficient, may be preferable for the treatment of shoulder pain. Further studies are needed to include these results in the prospective treatment guidelines.

Rotation, Stability and Transport

Energy Technology Data Exchange (ETDEWEB)

Connor, J. W.

2007-07-01

Tokamak plasmas can frequently exhibit high levels of rotation and rotation shear. This can usually be attributed to various sources: injection of momentum, e.g. through neutral beams, flows driven by plasma gradients or torques resulting from non-ambipolar particle loss; however, the source sometimes remains a mystery, such as the spontaneous rotation observed in Ohmic plasmas. The equilibrium rotation profile is given by the balance of these sources with transport and other losses; the edge boundary conditions can play an important role in determining this profile . Such plasma rotation, particularly sheared rotation, is predicted theoretically to have a significant influence on plasma behaviour. In the first place, sonic flows can significantly affect tokamak equilibria and neoclassical transport losses. However, the influence of rotation on plasma stability and turbulence is more profound. At the macroscopic level it affects the behaviour of the gross MHD modes that influence plasma operational limits. This includes sawteeth, the seeding of neoclassical tearing modes, resistive wall modes and the onset of disruptions through error fields, mode locking and reconnection. At the microscopic level it has a major effect on the stability of ballooning modes, both ideal MHD and drift wave instabilities such as ion temperature gradient (ITG) modes. In the non-linear state, as unstable drift waves evolve into turbulent structures, sheared rotation also tears apart eddies, thereby reducing the resulting transport. There is considerable experimental evidence for these effects on both MHD stability and plasma confinement. In particular, the appearance of improved confinement modes with transport barriers, such as edge H-mode barriers and internal transport barriers (ITBs) appears to correlate well with the presence of sheared plasma rotation. This talk will describe the theory underlying some of these phenomena involving plasma rotation, on both macroscopic and microscopic

Harvesting of short rotation coppice. Harvesting trials with a cut and storage system in Germany

Energy Technology Data Exchange (ETDEWEB)

Schweier, J.; Becker, G.

2012-11-01

Short rotation coppice (SRC) harvesting techniques are available in Germany, but broad experience and knowledge about machine performance and the related effective costs of harvesting operations are still missing. This information is crucial, as harvesting costs strongly influence the economic performance of the overall supply chain. Therefore, it was the aim of this study to collect and analyze productivity data of different harvesting systems for SRC. The combined cut and chip system on the one hand and the cut and storage system on the other hand were studied by literature review. Several studies analyze the combined cut and chip systems and the reported machine productivities showed great variations. The average was 30 green tons per scheduled machine hour (gt smh{sup -1}). Few studies are analysing the cut and storage system. They report that machines still are under development and that further research is needed. Therefore, time studies of harvesting operations using the cut and storage system were carried out. Five trials were performed with the harvesting machine 'Stemster MK III' developed by Nordic Biomass. The share of productive working time was 85% and the average productivity was 21 gt smh{sup -1}. These results were compared with values from the literature. Resulting harvesting costs were calculated per oven dry ton (Euro odt{sup -1}). The advantages and disadvantages of both harvesting systems are highlighted. (orig.)

Numerical investigation on nonlinear effect and vortex formation of oscillatory flow throughout a short tube in a thermoacoustic Stirling engine

Science.gov (United States)

Yang, Peng; Chen, Hui; Liu, Yingwen

2017-06-01

In this paper, a two-dimensional axisymmetric model of a thermoacoustic Stirling engine with a short tube where the cross section narrows has been developed. The transient streamlines and vortex formation through short tubes with different diameters in oscillatory flow have been investigated visually by computational fluid dynamics. Three dimensionless parameters, Reynolds number (Re), Keulegan-Carpenter number (KC), and Womersley number (Wo), are used to describe the flow regime and vortex characteristic throughout the short tube. High Re and Wo numbers indicate that the oscillatory flow develops into the turbulent flow through the short tube. The KC number has a direct effect on the transition of streamlines and the development of the vortex. For a small cross section where KC ≈ 1, streamlines rotate and the vortex forms at both sides of the short tube. The vortex stays in the main flow region, and intensity varies as streamlines are convected downstream. The velocity along the radius presents a Poiseuille profile within the influence of the vortex. For a large cross section where KC < 1, streamlines pass the short tube with little rotation and the vortex disappears in the main flow region and confines near the short tube. The velocity profile tends to be flat. The nonlinear effects including instantaneous pressure drop and power dissipation throughout the short tube are also discussed. It shows that the time averaged pressure drop is generated at the cost of power dissipation. Finally, the "effectiveness" is applied to evaluate the performance of the short tube. The results suggest that increasing the diameter of the short tube is in favor of reducing power dissipation, which is beneficial to improve "effectiveness."

Rotational Seismology: AGU Session, Working Group, and Website

Science.gov (United States)

Lee, William H.K.; Igel, Heiner; Todorovska, Maria I.; Evans, John R.

2007-01-01

Introduction Although effects of rotational motions due to earthquakes have long been observed (e. g., Mallet, 1862), nevertheless Richter (1958, p. 213) stated that: 'Perfectly general motion would also involve rotations about three perpendicular axes, and three more instruments for these. Theory indicates, and observation confirms, that such rotations are negligible.' However, Richter provided no references for this claim. Seismology is based primarily on the observation and modeling of three-component translational ground motions. Nevertheless, theoretical seismologists (e.g., Aki and Richards, 1980, 2002) have argued for decades that the rotational part of ground motions should also be recorded. It is well known that standard seismometers are quite sensitive to rotations and therefore subject to rotation-induced errors. The paucity of observations of rotational motions is mainly the result of a lack, until recently, of affordable rotational sensors of sufficient resolution. Nevertheless, in the past decade, a number of authors have reported direct observations of rotational motions and rotations inferred from rigid-body rotations in short baseline accelerometer arrays, creating a burgeoning library of rotational data. For example, ring laser gyros in Germany and New Zealand have led to the first significant and consistent observations of rotational motions from distant earthquakes (Igel et al., 2005, 2007). A monograph on Earthquake Source Asymmetry, Structural Media and Rotation Effects was published recently as well by Teisseyre et al. (2006). Measurement of rotational motions has implications for: (1) recovering the complete ground-displacement history from seismometer recordings; (2) further constraining earthquake rupture properties; (3) extracting information about subsurface properties; and (4) providing additional ground motion information to earthquake engineers for seismic design. A special session on Rotational Motions in Seismology was convened by H

The development of a wood fuel gasification plant utilising short rotation coppice and forestry residues: project ARBRE

International Nuclear Information System (INIS)

Pitcher, K.F.; Lundbergt, H.

1997-01-01

This paper will discuss the development of ARBRE Energy, a joint venture company that includes Yorkshire Environmental of the United Kingdom and Tenniska Processer AB of Sweden. The project will establish 2000 hectares of short rotation coppices, some of which will be organically fertilized with digested sewage sludges, to provide 80% of the fuel requirements of a biomass integrated gasification combined cycle (BIGCC) electricity generation plant. The remaining 20% of the fuel requirements will come from forestry waste, although in the first 5 years all the fuel will come from the forestry sources until the coppices are mature. The project will construct a gasification plant at Eggborough, North Yorkshire, England, which will provide gas to a gas turbine and steam turbine generation system, producing 10 MW and exporting 8 MW of electricity. It has been included in the 1993 tranche of the UK's Non Fossil Fuel Obligation (NFFO) and has gained financial support from the European Commission's THERMIE programme as a targeted BIGCC project. The project's technical and environmental effects and benefits will be examined in detail, together with the award of its planning permit and agreement on its operating license. (author)

The role of Duschinsky rotation in intersystem crossing: A case study of uracil

Directory of Open Access Journals (Sweden)

Etinski Mihajlo

2011-01-01

Full Text Available The intersystem crossing rate for the transition between the lowest excited singlet and triplet electronic states of uracil was studied by means of ab initio methods. The rate was evaluated using the timedependent approach based on the correlation function and its two approximations: the second-order cumulant expansion and the short-time approximation. The normal modes of the singlet and triplet states are related by the Duschinsky transformation, i.e., by rotation and translation. It was found that for singlet-triplet adiabatic energy gaps below 6000 cm-1, the inclusion of the Duschinsky rotation is necessary for quantitative results. Above energy gaps of 6000 cm-1, the rates obtained with and without the Duschinsky rotation are similar. The cumulant expansion approximates well the correlation function. The short-time approximation, although crude, can be used as the first estimate of the rate.

Acoustic rotation modes in complex plasmas

International Nuclear Information System (INIS)

Bai Dongxue; Wang Zhengxiong; Wang Xiaogang

2004-01-01

Acoustic rotation modes in complex plasmas are investigated in a cylindrical system with an axial symmetry. The linear mode solution is derived. The mode in an infinite area is reduced to a classical dust acoustic wave in the region away from the centre. When the dusty plasma is confined in a finite region, the breathing and rotating-void behaviour are observed. Vivid structures of different mode number solutions are illustrated

Assessing Regional-Scale Impacts of Short Rotation Coppices on Ecosystem Services by Modeling Land-Use Decisions.

Science.gov (United States)

Schulze, Jule; Frank, Karin; Priess, Joerg A; Meyer, Markus A

2016-01-01

Meeting the world's growing energy demand through bioenergy production involves extensive land-use change which could have severe environmental and social impacts. Second generation bioenergy feedstocks offer a possible solution to this problem. They have the potential to reduce land-use conflicts between food and bioenergy production as they can be grown on low quality land not suitable for food production. However, a comprehensive impact assessment that considers multiple ecosystem services (ESS) and biodiversity is needed to identify the environmentally best feedstock option, as trade-offs are inherent. In this study, we simulate the spatial distribution of short rotation coppices (SRCs) in the landscape of the Mulde watershed in Central Germany by modeling profit-maximizing farmers under different economic and policy-driven scenarios using a spatially explicit economic simulation model. This allows to derive general insights and a mechanistic understanding of regional-scale impacts on multiple ESS in the absence of large-scale implementation. The modeled distribution of SRCs, required to meet the regional demand of combined heat and power (CHP) plants for solid biomass, had little or no effect on the provided ESS. In the policy-driven scenario, placing SRCs on low or high quality soils to provide ecological focus areas, as required within the Common Agricultural Policy in the EU, had little effect on ESS. Only a substantial increase in the SRC production area, beyond the regional demand of CHP plants, had a relevant effect, namely a negative impact on food production as well as a positive impact on biodiversity and regulating ESS. Beneficial impacts occurred for single ESS. However, the number of sites with balanced ESS supply hardly increased due to larger shares of SRCs in the landscape. Regression analyses showed that the occurrence of sites with balanced ESS supply was more strongly driven by biophysical factors than by the SRC share in the landscape. This

Controlling the quantum rotational dynamics of a driven planar rotor ...

Indian Academy of Sciences (India)

Archana Shukla

†Dedicated to the memory of late Professor Charusita Chakravarty. To a large extent the ..... study the long time quantum dynamics using only the one cycle propagator. .... distributions, including the short time rotational rain- bow features and ...

Biomass production of dense direct-seeded lodgepole pine (Pinus contorta) at short rotation periods

Energy Technology Data Exchange (ETDEWEB)

Backlund, I.; Bergsten, U.

2012-07-01

Lodgepole pine (Pinus contorta) is a fast-growing species that is suitable for producing woody biomass in Nordic countries. Direct seeding of this species is cheaper than planting and creates dense, stable stands. The objective of this study was to quantify the stem volume and biomass production of direct seeded lodgepole pine stands grown under different site conditions with different stem densities, at an age that would permit extensive harvesting of biomass. A circle-plot inventory was performed in 16 of the oldest direct seeded lodgepole pine stands in mid-northern Sweden. Stemwood production of almost 200 m{sup 3}/ha was achieved on average on the best sites, rising to about 300 m{sup 3}/ha for the best circle-plots within 30 years of direct seeding despite the fact that pre-commercial thinning was made once or twice. This corresponds to 100 and 140 tons of dry weight biomass/ha, respectively. Higher stand stem densities ({>=}3000 st/ha) yielded more biomass with only slight reductions in diameter at breast height. The development of stem volume with respect to dominant height in direct seeded stands was becoming comparable to that in planted stands with similar spacing. It therefore seems that there is an unutilized potential for cost-effectively growing lodgepole pine in dense stands for biomass production after direct seeding. It may be possible to devise regimes for short(er) rotation forestry that would yield substantial amount of inexpensive biomass for biorefineries within a few decades. (orig.)

Does successful rotator cuff repair improve muscle atrophy and fatty infiltration of the rotator cuff? A retrospective magnetic resonance imaging study performed shortly after surgery as a reference.

Science.gov (United States)

Hamano, Noritaka; Yamamoto, Atsushi; Shitara, Hitoshi; Ichinose, Tsuyoshi; Shimoyama, Daisuke; Sasaki, Tsuyoshi; Kobayashi, Tsutomu; Kakuta, Yohei; Osawa, Toshihisa; Takagishi, Kenji

2017-06-01

Muscle atrophy and fatty infiltration in the rotator cuff muscles are often observed in patients with chronic rotator cuff tears. The recovery from these conditions has not been clarified. Ninety-four patients were included in this study. The improvement in muscle atrophy and fatty infiltration in successfully repaired rotator cuff tears was evaluated by magnetic resonance imaging at 1 year and 2 years after surgery and was compared with muscle atrophy and fatty infiltration observed on magnetic resonance imaging at 2 weeks after surgery to discount any changes due to the medial retraction of the torn tendon. The patients' muscle strength was evaluated in abduction and external rotation. Muscle atrophy and fatty infiltration of the supraspinatus were significantly improved at 2 years after surgery in comparison to 2 weeks after surgery. The subjects' abduction and external rotation strength was also significantly improved at 2 years after surgery in comparison to the preoperative values. Patients whose occupation ratio was improved had a better abduction range of motion, stronger abduction strength, and higher Constant score. Patients whose fatty infiltration was improved had a better range of motion in flexion and abduction, whereas the improvements of muscle strength and the Constant score were similar in the group that showed an improvement of fatty infiltration and the group that did not. Muscle atrophy and fatty infiltration can improve after rotator cuff repair. The strengths of abduction and external rotation were also improved at 2 years after surgery. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Nugget Structure Evolution with Rotation Speed for High-Rotation-Speed Friction-Stir-Welded 6061 Aluminum Alloy

Science.gov (United States)

Zhang, H. J.; Wang, M.; Zhu, Z.; Zhang, X.; Yu, T.; Wu, Z. Q.

2018-03-01

High-rotation-speed friction stir welding (HRS-FSW) is a promising technique to reduce the welding loads during FSW and thus facilitates the application of FSW for in situ fabrication and repair. In this study, 6061 aluminum alloy was friction stir welded at high-rotation speeds ranging from 3000 to 7000 rpm at a fixed welding speed of 50 mm/min, and the effects of rotation speed on the nugget zone macro- and microstructures were investigated in detail in order to illuminate the process features. Temperature measurements during HRS-FSW indicated that the peak temperature did not increase consistently with rotation speed; instead, it dropped remarkably at 5000 rpm because of the lowering of material shear stress. The nugget size first increased with rotation speed until 5000 rpm and then decreased due to the change of the dominant tool/workpiece contact condition from sticking to sliding. At the rotation speed of 5000 rpm, where the weld material experienced weaker thermal effect and higher-strain-rate plastic deformation, the nugget exhibited relatively small grain size, large textural intensity, and high dislocation density. Consequently, the joint showed superior nugget hardness and simultaneously a slightly low tensile ductility.

Multi-vortex crystal lattices in Bose-Einstein condensates with a rotating trap.

Science.gov (United States)

Xie, Shuangquan; Kevrekidis, Panayotis G; Kolokolnikov, Theodore

2018-05-01

We consider vortex dynamics in the context of Bose-Einstein condensates (BECs) with a rotating trap, with or without anisotropy. Starting with the Gross-Pitaevskii (GP) partial differential equation (PDE), we derive a novel reduced system of ordinary differential equations (ODEs) that describes stable configurations of multiple co-rotating vortices (vortex crystals). This description is found to be quite accurate quantitatively especially in the case of multiple vortices. In the limit of many vortices, BECs are known to form vortex crystal structures, whereby vortices tend to arrange themselves in a hexagonal-like spatial configuration. Using our asymptotic reduction, we derive the effective vortex crystal density and its radius. We also obtain an asymptotic estimate for the maximum number of vortices as a function of rotation rate. We extend considerations to the anisotropic trap case, confirming that a pair of vortices lying on the long (short) axis is linearly stable (unstable), corroborating the ODE reduction results with full PDE simulations. We then further investigate the many-vortex limit in the case of strong anisotropic potential. In this limit, the vortices tend to align themselves along the long axis, and we compute the effective one-dimensional vortex density, as well as the maximum admissible number of vortices. Detailed numerical simulations of the GP equation are used to confirm our analytical predictions.

Controlling rotational deformity in ankle fractures : the Bridgend ...

African Journals Online (AJOL)

Management. Recognition of the forces is usually possible by observing the pattern of the fracture lines, especially in the fibula. Abduction and adduction forces cause transverse or short oblique fracture lines near the level of the ankle joint (Fig 1) whereas rotation forces produce spiral fractures of the fibula above the level ...

Observations on rotating needle insertions using a brachytherapy robot

International Nuclear Information System (INIS)

Meltsner, M A; Ferrier, N J; Thomadsen, B R

2007-01-01

A robot designed for prostate brachytherapy implantations has the potential to greatly improve treatment success. Much of the research in robotic surgery focuses on measuring accuracy. However, there exist many factors that must be optimized before an analysis of needle placement accuracy can be determined. Some of these parameters include choice of the needle type, insertion velocity, usefulness of the rotating needle and rotation speed. These parameters may affect the force at which the needle interacts with the tissue. A reduction in force has been shown to decrease the compression of the prostate and potentially increase the accuracy of seed position. Rotating the needle as it is inserted may reduce frictional forces while increasing accuracy. However, needle rotations are considered to increase tissue damage due to the drilling nature of the insertion. We explore many of the factors involved in optimizing a brachytherapy robot, and the potential effects each parameter may have on the procedure. We also investigate the interaction of rotating needles in gel and suggest the rotate-cannula-only method of conical needle insertion to minimize any tissue damage while still maintaining the benefits of reduced force and increased accuracy

Reduced short interval cortical inhibition correlates with atomoxetine response in children with attention-deficit hyperactivity disorder (ADHD).

Science.gov (United States)

Chen, Tina H; Wu, Steve W; Welge, Jeffrey A; Dixon, Stephan G; Shahana, Nasrin; Huddleston, David A; Sarvis, Adam R; Sallee, Floyd R; Gilbert, Donald L

2014-12-01

Clinical trials in children with attention-deficit hyperactivity disorder (ADHD) show variability in behavioral responses to the selective norepinephrine reuptake inhibitor atomoxetine. The objective of this study was to determine whether transcranial magnetic stimulation-evoked short interval cortical inhibition might be a biomarker predicting, or correlating with, clinical atomoxetine response. At baseline and after 4 weeks of atomoxetine treatment in 7- to 12-year-old children with ADHD, transcranial magnetic stimulation short interval cortical inhibition was measured, blinded to clinical improvement. Primary analysis was by multivariate analysis of covariance. Baseline short interval cortical inhibition did not predict clinical responses. However, paradoxically, after 4 weeks of atomoxetine, mean short interval cortical inhibition was reduced 31.9% in responders and increased 6.1% in nonresponders (analysis of covariance t 41 = 2.88; P = .0063). Percentage reductions in short interval cortical inhibition correlated with reductions in the ADHD Rating Scale (r = 0.50; P = .0005). In children ages 7 to 12 years with ADHD treated with atomoxetine, improvements in clinical symptoms are correlated with reductions in motor cortex short interval cortical inhibition. © The Author(s) 2014.

A novel rotational invariants target recognition method for rotating motion blurred images

Science.gov (United States)

Lan, Jinhui; Gong, Meiling; Dong, Mingwei; Zeng, Yiliang; Zhang, Yuzhen

2017-11-01

The imaging of the image sensor is blurred due to the rotational motion of the carrier and reducing the target recognition rate greatly. Although the traditional mode that restores the image first and then identifies the target can improve the recognition rate, it takes a long time to recognize. In order to solve this problem, a rotating fuzzy invariants extracted model was constructed that recognizes target directly. The model includes three metric layers. The object description capability of metric algorithms that contain gray value statistical algorithm, improved round projection transformation algorithm and rotation-convolution moment invariants in the three metric layers ranges from low to high, and the metric layer with the lowest description ability among them is as the input which can eliminate non pixel points of target region from degenerate image gradually. Experimental results show that the proposed model can improve the correct target recognition rate of blurred image and optimum allocation between the computational complexity and function of region.

Firewood yield and profitability of a traditional Daniellia oliveri short-rotation coppice on fallow lands in Benin

International Nuclear Information System (INIS)

Avohou, T. Hermane; Houehounha, Remy; Glele-Kakai, Romain; Assogbadjo, Achille Ephrem; Sinsin, Brice

2011-01-01

Sub-Saharan Africa has a great diversity of local coppicing species which are exploited in traditional short coppice systems for firewood. Biomass yield and profitability of these systems as well as their responses to silvicultural improvement are little known. This study evaluated the firewood yield and the profitability of a traditional Daniellia oliveri short-rotation coppice on fallow lands in central Benin. Two weed management options were considered: (1) the weedy option, usually practiced by locals, which experienced grass competition and bushfires, and (2) the weed-free option, which consisted in periodic removal of grasses and other species. Destructive measurements and allometric equations were used to estimate biomass yield in 12 plots over 42 months. A cost-benefit analysis model based on the net present value and the benefit-cost ratio was used to compare the profitability of the two management options. Biomass accumulation rate averaged 1.08 ± 0.20 tonnes of dry matter ha -1 year -1 (t DM ha -1 year -1 ) in weedy conditions. Weed removal improved 3.5 times this rate in weed-free plots (3.83 ± 0.47 t DM ha -1 year -1 ). After 42 months, total biomass reached 3.67 ± 0.65 t DM ha -1 in weedy plots and 11.63 ± 0.76 t DM ha -1 in weed-free plots. Most of the biomass (≥88%) was marketable in local markets. Coppice exploitation was profitable after 24 months for both management options. Weed removal improved the profits three times. A sensitivity analysis showed that both options were still profitable with up to 25% increase of labour and transport costs, 25% decrease of biomass price and 12% increase of the discount rate. (author)

Dynamic ocean-tide effects on Earth's rotation

Science.gov (United States)

Dickman, S. R.

1993-01-01

This article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.

Identification of petroleum hydrocarbons using a reduced number of PAHs selected by Procrustes rotation.

Science.gov (United States)

Fernández-Varela, R; Andrade, J M; Muniategui, S; Prada, D; Ramírez-Villalobos, F

2010-04-01

Identifying petroleum-related products released into the environment is a complex and difficult task. To achieve this, polycyclic aromatic hydrocarbons (PAHs) are of outstanding importance nowadays. Despite traditional quantitative fingerprinting uses straightforward univariate statistical analyses to differentiate among oils and to assess their sources, a multivariate strategy based on Procrustes rotation (PR) was applied in this paper. The aim of PR is to select a reduced subset of PAHs still capable of performing a satisfactory identification of petroleum-related hydrocarbons. PR selected two subsets of three (C(2)-naphthalene, C(2)-dibenzothiophene and C(2)-phenanthrene) and five (C(1)-decahidronaphthalene, naphthalene, C(2)-phenanthrene, C(3)-phenanthrene and C(2)-fluoranthene) PAHs for each of the two datasets studied here. The classification abilities of each subset of PAHs were tested using principal components analysis, hierarchical cluster analysis and Kohonen neural networks and it was demonstrated that they unraveled the same patterns as the overall set of PAHs. (c) 2009 Elsevier Ltd. All rights reserved.

Increased supraspinatus tendon thickness following fatigue loading in rotator cuff tendinopathy: potential implications for exercise therapy.

Science.gov (United States)

McCreesh, Karen M; Purtill, Helen; Donnelly, Alan E; Lewis, Jeremy S

2017-01-01

Exercise imparts a load on tendon tissue that leads to changes in tendon properties. Studies suggest that loading immediately reduces tendon thickness, with a loss of this response in symptomatic tendinopathy. No studies investigating the response of tendon dimensions to load for the rotator cuff tendons exist. This study aimed to examine the short-term effect of loading on the thickness of the supraspinatus tendon and acromiohumeral distance those with and without rotator cuff tendinopathy. Participants were 20 painfree controls, and 23 people with painful rotator cuff tendinopathy. Supraspinatus tendon thickness and acromiohumeral distance were measured using ultrasound scans before, and at three time points after loading (1, 6 and 24 hours). Loading involved isokinetic eccentric and concentric external rotation and abduction. There was a significant increase in supraspinatus tendon thickness in the pain group at 1 (7%, ∆=0.38, 95% CI 0.19 to 0.57) and 6 hours (11%, ∆=0.53, 95% CI 0.34 to 0.71), although only the 6 hours difference exceeded minimal detectable difference. In contrast, there was a small non-significant reduction in thickness in controls. The acromiohumeral distance reduced significantly in both groups at 1 hour (controls: ∆=0.64, 95% CI 0.38 to 0.90; pain: ∆=1.1, 95% CI 0.85 to 1.33), with a larger change from baseline in the pain group. Those diagnosed with painful supraspinatus tendinopathy demonstrated increased thickening with delayed return to baseline following loading. Rehabilitation professionals may need to take into account the impact of loading to fatigue when planning rehabilitation programmes.

A Numerical-Analytical Approach to Modeling the Axial Rotation of the Earth

Science.gov (United States)

Markov, Yu. G.; Perepelkin, V. V.; Rykhlova, L. V.; Filippova, A. S.

2018-04-01

A model for the non-uniform axial rotation of the Earth is studied using a celestial-mechanical approach and numerical simulations. The application of an approximate model containing a small number of parameters to predict variations of the axial rotation velocity of the Earth over short time intervals is justified. This approximate model is obtained by averaging variable parameters that are subject to small variations due to non-stationarity of the perturbing factors. The model is verified and compared with predictions over a long time interval published by the International Earth Rotation and Reference Systems Service (IERS).

Magnetic nanofluids and magnetic composite fluids in rotating seal systems

International Nuclear Information System (INIS)

Borbath, T; Borbath, I; Boros, T; Bica, D; Vekas, L; Potencz, I

2010-01-01

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. The behavior of different types of magnetizable fluids in the rotating sealing systems is analyzed. Design concepts, some constructive details and testing procedures of magnetofluidic rotating seals are presented such as the testing equipment. The main characteristics of several magnetofluidic sealing systems and their applications will be presented: vacuum deposition systems and liquefied gas pumps applications, mechanical and magnetic nanofluid combined seals, gas valves up to 40 bar equipped by rotating seal with magnetic nanofluids and magnetic composite fluids.

Production physiology and morphology of Populus species and their hybrids grown under short rotation. II. Biomass components and harvest index of hybrid and parental species clones

Energy Technology Data Exchange (ETDEWEB)

Scarascia-Mugnozza, G. E. [Univ. of Tuscia, Viterbo, (Italy); Ceulemans, R. [Antwerp Univ., Wilrijk (Belgium); Heilman, P. E. [Washington State Univ., Olympia, WA (United States); Isebrands, J. G.; Stettler, R. F.; Hinckley, T. M. [Forest Service, Rhinelander, WI (United States). North Central Forest Experiment Station

1997-03-01

Growth and biomass components of four poplar clones were studied during four consecutive years of short-rotation culture in western Washington, U.S.A. Results confirmed previous observations indicating the high productive potential of hybrid clones. In two of the hybrid clones tested, large differences in biomass distribution among tree components and in the pattern of growth were evident, as indicated by harvest index and root/shoot ratios. Results suggest that the clonal differences shown in total biomass, in allocation to different tree components, and in harvest index, have important implications for future poplar breeding programs. 39 refs., 4 tabs., 4 figs.

Rotation and rotation-vibration spectroscopy of the 0+-0- inversion doublet in deuterated cyanamide.

Science.gov (United States)

Kisiel, Zbigniew; Kraśnicki, Adam; Jabs, Wolfgang; Herbst, Eric; Winnewisser, Brenda P; Winnewisser, Manfred

2013-10-03

The pure rotation spectrum of deuterated cyanamide was recorded at frequencies from 118 to 649 GHz, which was complemented by measurement of its high-resolution rotation-vibration spectrum at 8-350 cm(-1). For D2NCN the analysis revealed considerable perturbations between the lowest Ka rotational energy levels in the 0(+) and 0(-) substates of the lowest inversion doublet. The final data set for D2NCN exceeded 3000 measured transitions and was successfully fitted with a Hamiltonian accounting for the 0(+) ↔ 0(-) coupling. A smaller data set, consisting only of pure rotation and rotation-vibration lines observed with microwave techniques was obtained for HDNCN, and additional transitions of this type were also measured for H2NCN. The spectroscopic data for all three isotopic species were fitted with a unified, robust Hamiltonian allowing confident prediction of spectra well into the terahertz frequency region, which is of interest to contemporary radioastronomy. The isotopic dependence of the determined inversion splitting, ΔE = 16.4964789(8), 32.089173(3), and 49.567770(6) cm(-1), for D2NCN, HDNCN, and H2NCN, respectively, is found to be in good agreement with estimates from a simple reduced quartic-quadratic double minimum potential.

Simulated surgical workshops enhance medical school students’ preparation for clinical rotation

Directory of Open Access Journals (Sweden)

Patricia Johnson

2013-02-01

Full Text Available BackgroundA major focus of the medical school curriculum is to ensure medical students are well prepared prior to entering clinical rotations, which includes the compulsory surgical rotation.AimsThe objective of this research was to design and formally evaluate a set of real-life surgical workshops aimed at better preparing medical students for their clinical rotation in surgery. These workshops would be incorporated into the pre-clinical medical school curriculum.MethodDedicated surgical workshops were introduced into the preclinical component of the Bachelor of Medicine/Bachelor of Surgery (MBBS program at our University in 2009. These workshops encompassed training in the clinical skills needed in the perioperative and wider hospital setting. A survey comprising of eight to nine ranked questions (utilising a five-point Likert Scale as well as three short answer questions was administered to the medical students after they completed their compulsory surgical clinical rotation.ResultsThe overall response rate to the survey evaluating the surgical workshops was 79% (123/155. The mean of the ranked questions ranged from 4.05 to 4.89 which indicated that the students found the workshops useful. When evaluating the short answer questions (via topic coding, additional information was provided that supported and explained the survey findings and also included suggestions for improvements.ConclusionThe findings of the medical student survey demonstrated the value of incorporating dedicated preparatory surgical workshops in the medical school pre-clinical curriculum. However, further research is warranted to determine if this inclusion translated into improved student performance during the clinical surgical rotation.

Long-term yield effects of establishment method and weed control in willow for short rotation coppice (SRC)

DEFF Research Database (Denmark)

Larsen, Søren Ugilt; Jørgensen, Uffe; Kjeldsen, Jens Bonderup

2014-01-01

matter (DM) yield was measured over 6 harvest rotations corresponding to 16 years. In 1st rotation, yield differed significantly between establishment methods with highest yield for 1.8 m rods (10.4 Mg ha−1 year−1), intermediate yield for cuttings and 0.2 m billets (8.6 and 8.5 Mg ha−1 year−1...... establishment methods; 1) vertical planting of standard 0.2 m cuttings; 2) horizontal planting of 0.1 m billets; 3) horizontal planting of 0.2 m billets; 4) horizontal planting of 1.8 m rods. All establishment methods were combined with mechanical and chemical weed control during the establishment year. Dry......, respectively) and lowest for 0.1 m billets (5.6 Mg ha−1 year−1). No differences were found in 2nd rotation. Over 1st and 2nd rotation, mechanical weed control resulted in significantly lower yield than chemical control when combined with 0.1 m billets. Cuttings and 1.8 m rods were compared over 1st, 2nd, 3rd...

Allometric equations commonly used for estimating shoot biomass in short-rotation wood energy species: a review

Directory of Open Access Journals (Sweden)

Julio Cesar Ríos-Saucedo

2016-01-01

Full Text Available Los cultivos dendroenergéticos de corta rotación en monte bajo (Short Rotation Coppice -SRC comúnmente están formados por individuos unifustales en el primer ciclo de corta, pero a partir del segundo ciclo, de cada cepa surgen numerosos vástagos o brotes, los cuales presentan desafíos interesantes al momento de estimar su biomasa. El objetivo de este trabajo fue identificar especies, longitud de rotación y tipos de modelos alométricos usados para estimar biomasa en SRC, en revistas científicas de las bases de datos Scopus y Web of Science. Entre los modelos para estimar la biomasa (y de uso más frecuente destaca el exponencial, que tiene como variable predictora el diámetro normal ( D ( y = b 0 D b 1 , diámetro basal de tallo ( Db ( y = b 0 Db b 1 y la combinación de diámetro normal al cuadrado por la altura total ( D 2 H ( y = b 0 + b 1 D 2 H . Los géneros con mayor número de modelos diferentes fueron Populus, Salix y Eucalyptus . Los dos primeros son los más estudiados. La longitud de rotación empleada en los cultivos estudiados varió de uno a 15 años.

Soil ecological impacts of the short rotation industry with poplar trees and pastures in Mecklenburg-Western Pomerania; Bodenoekologische Auswirkungen der Kurzumtriebswirtschaft mit Pappeln und Weiden in Mecklenburg-Vorpommern

Energy Technology Data Exchange (ETDEWEB)

Kahle, Petra; Moeller, Josefine; Seelig, Andreas; Baum, Christel [Rostock Univ. (Germany). Professur Bodenphysik und Ressourcenschutz

2013-10-01

The impact of short rotation coppice (SRC), a former soil rotation coppice (FRC) and a continuously annually tilled arable soil (TS) on different soil properties was investigated. Parameters were chemical soil properties, like the concentration of soil organic matter (SOC) and total nitrogen (Nt), physical soil properties, like the bulk density, porosity and aggregate stability and biological soil properties, like abundance and biomass of earth worms. The return to annual crops involved an intense tillage and aeration of the soil. The study indicated, that the lack of tillage under SRC and the quantity of leaf and root litter can lead to an increased carbon accumulation in the upper soil. Tillage of former SRC leads to a fast redistribution of SOC in the topsoil combined with a loss of porosity, aggregate stability and abundance of earth worms. Subsequent investigations should contribute to select tillage strategies for FRC, which contribute to conserve the accumulated SOC and decrease the impact on the porosity and aggregate stability. (orig.)

Reducing the Risk of Damage to Power Transformers of 110 kV and Above Accompanying Internal Short Circuits

Energy Technology Data Exchange (ETDEWEB)

L’vova, M. M. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); L’vov, S. Yu. [Presselektro LLC (Russian Federation); Komarov, V. B. [IPCE RAS (Russian Federation); Lyut’ko, E. O. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); Vdoviko, V. P. [EMA Ltd. (Russian Federation); Demchenko, V. V. [JSC “Boguchanskaya HPP” (Russian Federation); Belyaev, S. G. [PKF Konif Ltd. (Russian Federation); Savel’ev, V. A. [Ivanovo State Power University (Russian Federation); L’vov, M. Yu., E-mail: timashova@nte-power.ru; L’vov, Yu. N. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation)

2015-03-15

Methods of increasing the operating reliability of power transformers, autotransformers and shunting reactors in order to reduce the risk of damage, which accompany internal short circuits and equipment fires and explosions, are considered.

Rotator cuff tendon connections with the rotator cable.

Science.gov (United States)

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

The evaluation of speed skating helmet performance through peak linear and rotational accelerations.

Science.gov (United States)

Karton, Clara; Rousseau, Philippe; Vassilyadi, Michael; Hoshizaki, Thomas Blaine

2014-01-01

Like many sports involving high speeds and body contact, head injuries are a concern for short track speed skating athletes and coaches. While the mandatory use of helmets has managed to nearly eliminate catastrophic head injuries such as skull fractures and cerebral haemorrhages, they may not be as effective at reducing the risk of a concussion. The purpose of this study was to evaluate the performance characteristics of speed skating helmets with respect to managing peak linear and peak rotational acceleration, and to compare their performance against other types of helmets commonly worn within the speed skating sport. Commercially available speed skating, bicycle and ice hockey helmets were evaluated using a three-impact condition test protocol at an impact velocity of 4 m/s. Two speed skating helmet models yielded mean peak linear accelerations at a low-estimated probability range for sustaining a concussion for all three impact conditions. Conversely, the resulting mean peak rotational acceleration values were all found close to the high end of a probability range for sustaining a concussion. A similar tendency was observed for the bicycle and ice hockey helmets under the same impact conditions. Speed skating helmets may not be as effective at managing rotational acceleration and therefore may not successfully protect the user against risks associated with concussion injuries.

Development and Deployment of a Short Rotation Woody Crops Harvesting System Based on a Case New Holland Forage Harvester and SRC Woody Crop Header

Energy Technology Data Exchange (ETDEWEB)

Eisenbies, Mark [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Volk, Timothy [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Abrahamson, Lawrence [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Shuren, Richard [GreenWood Resources, Inc., Portland, OR (United States); Stanton, Brian [GreenWood Resources, Inc., Portland, OR (United States); Posselius, John [Case New Holland, New Holland, PA (United States); McArdle, Matt [Mesa Reduction Engineering and Processing, Inc., Auburn, NY (United States); Karapetyan, Samvel [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Patel, Aayushi [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Shi, Shun [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States); Zerpa, Jose [State Univ. of New York College of Environmental Science and Forestry (SUNY-ESF), Syracuse, NY (United States)

2014-10-03

Biomass for biofuels, bioproducts and bioenergy can be sourced from forests, agricultural crops, various residue streams, and dedicated woody or herbaceous crops. Short rotation woody crops (SRWC), like willow and hybrid poplar, are perennial cropping systems that produce a number of environmental and economic development benefits in addition to being a renewable source of biomass that can be produced on marginal land. Both hybrid poplar and willow have several characteristics that make them an ideal feedstock for biofuels, bioproducts, and bioenergy; these include high yields that can be obtained in three to four years, ease of cultivar propagation from dormant cuttings, a broad underutilized genetic base, ease of breeding, ability to resprout after multiple harvests, and feedstock composition similar to other sources of woody biomass. Despite the range of benefits associated with SRWC systems, their deployment has been restricted by high costs, low market acceptance associated with inconsistent chip quality (see below for further explanation), and misperceptions about other feedstock characteristics (see below for further explanation). Harvesting of SRWC is the largest single cost factor (~1/3 of the final delivered cost) in the feedstock supply system. Harvesting is also the second largest input of primary fossil energy in the system after commercial N fertilizer, accounting for about one third of the input. Therefore, improving the efficiency of the harvesting system has the potential to reduce both cost and environmental impact. At the start of this project, we projected that improving the overall efficiency of the harvesting system by 25% would reduce the delivered cost of SRWC by approximately $0.50/MMBtu (or about $7.50/dry ton). This goal was exceeded over the duration of this project, as noted below.

Artificial gravity: head movements during short-radius centrifugation

NARCIS (Netherlands)

Young, L. R.; Hecht, H.; Lyne, L. E.; Sienko, K. H.; Cheung, C. C.; Kavelaars, J.

2001-01-01

Short-radius centrifugation is a potential countermeasure to long-term weightlessness. Unfortunately, head movements in a rotating environment induce serious discomfort, non-compensatory vestibulo-ocular reflexes, and subjective illusions of body tilt. In two experiments we investigated the effects

Exercise following a short immobilization period is detrimental to tendon properties and joint mechanics in a rat rotator cuff injury model.

Science.gov (United States)

Peltz, Cathryn D; Sarver, Joseph J; Dourte, Leann M; Würgler-Hauri, Carola C; Williams, Gerald R; Soslowsky, Louis J

2010-07-01

Rotator cuff tears are a common clinical problem that can result in pain and disability. Previous studies in a rat model showed enhanced tendon to bone healing with postoperative immobilization. The objective of this study was to determine the effect of postimmobilization activity level on insertion site properties and joint mechanics in a rat model. Our hypothesis was that exercise following a short period of immobilization will cause detrimental changes in insertion site properties compared to cage activity following the same period of immobilization, but that passive shoulder mechanics will not be affected. We detached and repaired the supraspinatus tendon of 22 Sprague-Dawley rats, and the injured shoulder was immobilized postoperatively for 2 weeks. Following immobilization, rats were prescribed cage activity or exercise for 12 weeks. Passive shoulder mechanics were determined, and following euthanasia, tendon cross-sectional area and mechanical properties were measured. Exercise following immobilization resulted in significant decreases compared to cage activity in range of motion, tendon stiffness, modulus, percent relaxation, and several parameters from both a structurally based elastic model and a quasi-linear viscoelastic model. Therefore, we conclude that after a short period of immobilization, increased activity is detrimental to both tendon mechanical properties and shoulder joint mechanics, presumably due to increased scar production. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc

MUSCLE ACTIVITY RESPONSE TO EXTERNAL MOMENT DURING SINGLE-LEG DROP LANDING IN YOUNG BASKETBALL PLAYERS: THE IMPORTANCE OF BICEPS FEMORIS IN REDUCING INTERNAL ROTATION OF KNEE DURING LANDING

Directory of Open Access Journals (Sweden)

Meguru Fujii

2012-06-01

Full Text Available Internal tibial rotation with the knee close to full extension combined with valgus collapse during drop landing generally results in non-contact anterior cruciate ligament (ACL injury. The purpose of this study was to investigate the relationship between internal rotation of the knee and muscle activity from internal and external rotator muscles, and between the internal rotation of knee and externally applied loads on the knee during landing in collegiate basketball players. Our hypothesis was that the activity of biceps femoris muscle would be an important factor reducing internal knee rotation during landing. The subjects were 10 collegiate basketball students: 5 females and 5 males. The subjects performed a single-leg drop landing from a 25-cm height. Femoral and tibial kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the knee angular motions were determined. Ground reaction forces and muscle activation patterns (lateral hamstring and medial hamstring were simultaneously measured and computed. Results indicated that lower peak internal tibial rotation angle at the time of landing was associated with greater lateral hamstring activity (r = -0.623, p < 0.001. When gender was considered, the statistically significant correlation remained only in females. There was no association between the peak internal tibial rotation angle and the knee internal rotation moment. Control of muscle activity in the lateral to medial hamstring would be an important factor in generating sufficient force to inhibit excessive internal rotation during landing. Strengthening the biceps femoris might mitigate the higher incidence of non-contact ACL injury in female athletes

Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror

Science.gov (United States)

Li, Steven

2011-01-01

A laser cavity was designed and implemented by using a wedged polarization rotator and a Porro prism in order to reduce the parts count, and to improve the laser reliability. In this invention, a z-cut quartz polarization rotator is used to compensate the wavelength retardance introduced by the Porro prism. The polarization rotator rotates the polarization of the linear polarized beam with a designed angle that is independent of the orientation of the rotator. This unique property was used to combine the retardance compensation and a Risley prism to a single optical component: a wedged polarization rotator. This greatly simplifies the laser alignment procedure and reduces the number of the laser optical components.

The various contributions in Venus rotation rate and LOD

Science.gov (United States)

Cottereau, L.; Rambaux, N.; Lebonnois, S.; Souchay, J.

2011-07-01

Context. Thanks to the Venus Express Mission, new data on the properties of Venus could be obtained, in particular concerning its rotation. Aims: In view of these upcoming results, the purpose of this paper is to determine and compare the major physical processes influencing the rotation of Venus and, more particularly, the angular rotation rate. Methods: Applying models already used for Earth, the effect of the triaxiality of a rigid Venus on its period of rotation are computed. Then the variations of Venus rotation caused by the elasticity, the atmosphere, and the core of the planet are evaluated. Results: Although the largest irregularities in the rotation rate of the Earth on short time scales are caused by its atmosphere and elastic deformations, we show that the irregularities for Venus are dominated by the tidal torque exerted by the Sun on its solid body. Indeed, as Venus has a slow rotation, these effects have a large amplitude of two minutes of time (mn). These variations in the rotation rate are greater than the one induced by atmospheric wind variations that can reach 25-50 s of time (s), depending on the simulation used. The variations due to the core effects that vary with its size between 3 and 20 s are smaller. Compared to these effects, the influence of the elastic deformation caused by the zonal tidal potential is negligible. Conclusions: As the variations in the rotation of Venus reported here are close to 3 mn peak to peak, they should influence past, present, and future observations, thereby providing further constraints on the planet's internal structure and atmosphere.

Enstrophy-based proper orthogonal decomposition of flow past rotating cylinder at super-critical rotating rate

Science.gov (United States)

Sengupta, Tapan K.; Gullapalli, Atchyut

2016-11-01

Spinning cylinder rotating about its axis experiences a transverse force/lift, an account of this basic aerodynamic phenomenon is known as the Robins-Magnus effect in text books. Prandtl studied this flow by an inviscid irrotational model and postulated an upper limit of the lift experienced by the cylinder for a critical rotation rate. This non-dimensional rate is the ratio of oncoming free stream speed and the surface speed due to rotation. Prandtl predicted a maximum lift coefficient as CLmax = 4π for the critical rotation rate of two. In recent times, evidences show the violation of this upper limit, as in the experiments of Tokumaru and Dimotakis ["The lift of a cylinder executing rotary motions in a uniform flow," J. Fluid Mech. 255, 1-10 (1993)] and in the computed solution in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)]. In the latter reference, this was explained as the temporal instability affecting the flow at higher Reynolds number and rotation rates (>2). Here, we analyze the flow past a rotating cylinder at a super-critical rotation rate (=2.5) by the enstrophy-based proper orthogonal decomposition (POD) of direct simulation results. POD identifies the most energetic modes and helps flow field reconstruction by reduced number of modes. One of the motivations for the present study is to explain the shedding of puffs of vortices at low Reynolds number (Re = 60), for the high rotation rate, due to an instability originating in the vicinity of the cylinder, using the computed Navier-Stokes equation (NSE) from t = 0 to t = 300 following an impulsive start. This instability is also explained through the disturbance mechanical energy equation, which has been established earlier in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)].

End-shorting and electric field in edge plasmas with application to field-reversed configurations

International Nuclear Information System (INIS)

Steinhauer, Loren C.

2002-01-01

The shorting of open field lines where they intersect external boundaries strongly modifies the transverse electric field all along the field lines. The modified electric field is found by an extension of the familiar Boltzmann relation for the electric potential. This leads to a prediction of the electric drift. Flow generation by electrical shorting is applied here to three aspects of elongated field-reversed configurations: plasma rotation rate; the particle-loss spin-up mechanism; and the sustainability of the rotating magnetic field current drive method

Ultra high energy electrons powered by pulsar rotation.

Science.gov (United States)

Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

2013-01-01

A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e(±)) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100 TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons.

A rotated Dynamic Nelson-Siegel model with macro-financial applications

OpenAIRE

Nyholm, Ken

2015-01-01

A factor rotation scheme is applied to the well-known Dynamic Nelson-Siegel model facilitating direct parametrization of the short rate process. The model-implied term structure of term premia is derived in closed-form, and macroeconomic variables are included in a Taylor-rule- type fashion. Four empirical experiments are performed on US data covering the period from 1990 to 2014. It is found that macroeconomic variables impact the evolution of the short rate until 2002, after which their eff...

Rotational loss of a ring-shaped flywheel supported by high Tc superconducting levitation

International Nuclear Information System (INIS)

Teshima, Hidekazu; Tawara, Taichi; Shimada, Ryuichi.

1997-01-01

This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T c superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

Wave-driven Rotation in Supersonically Rotating Mirrors

Energy Technology Data Exchange (ETDEWEB)

A. Fetterman and N.J. Fisch

2010-02-15

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Wave-driven Rotation in Supersonically Rotating Mirrors

International Nuclear Information System (INIS)

Fetterman, A.; Fisch, N.J.

2010-01-01

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

Energy Technology Data Exchange (ETDEWEB)

Lee, Eve J.; Chiang, Eugene, E-mail: evelee@berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2017-06-10

Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ∼10 days, but dwindle in number at shorter periods. Both the break at ∼10 days and the slope of the occurrence rate down to ∼1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (<1 day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short-period planets are more widely spaced than their longer-period counterparts. Our picture provides a starting point for understanding why the sub-Neptune population drops at ∼10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ∼1 day instead of ∼10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).

Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

International Nuclear Information System (INIS)

Lee, Eve J.; Chiang, Eugene

2017-01-01

Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ∼10 days, but dwindle in number at shorter periods. Both the break at ∼10 days and the slope of the occurrence rate down to ∼1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (<1 day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short-period planets are more widely spaced than their longer-period counterparts. Our picture provides a starting point for understanding why the sub-Neptune population drops at ∼10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ∼1 day instead of ∼10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).

The Acoustical Behavior of Contra-Rotating Fan

Directory of Open Access Journals (Sweden)

Juan Wu

2018-01-01

Full Text Available The noise produced by a contra-rotating ventilator can cause injury to humans. Therefore, it is important to reduce noise caused by ventilators. In this study, the Ffowcs Williams and Hawkings (FW-H model was used to simulate the acoustics of four different axial impeller spacing points based on the unsteady flow field through a FBD No. 8.0 contra-rotating ventilator. Experiments were conducted to verify the correctness of the numerical model. Meanwhile, the Variable Frequency Drive (VFD drives the two motors of 55 kW to give the impellers different speeds to distinguish different conditions. The results showed that the main noise source of the ventilator was the two rotating impellers and the area between them. For the same axial space, the noise decreased with the increase of flow rate and then decreased. And the amplitude of the discrete pulse increased gradually. It can be concluded that the vortex acoustics decreased gradually with the increase of flow rate and the rotating acoustics were the major contributor. With the axial distance increasing, the noise caused by the two impellers was weak, and the frequencies of sound pressure level moved toward medium- and low-frequency bands gradually. The suitable axial space could reduce noise and improve the working environment.

Semiclassical shell structure in rotating Fermi systems

International Nuclear Information System (INIS)

Magner, A. G.; Sitdikov, A. S.; Khamzin, A. A.; Bartel, J.

2010-01-01

The collective moment of inertia is derived analytically within the cranking model for any rotational frequency of the harmonic-oscillator potential well and at a finite temperature. Semiclassical shell-structure components of the collective moment of inertia are obtained for any potential by using the periodic-orbit theory. We found semiclassically their relation to the free-energy shell corrections through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. The shell effects in the moment of inertia exponentially disappear with increasing temperature. For the case of the harmonic-oscillator potential, one observes a perfect agreement of the semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures.

Short Rotation Forestry (SRF in a Mediterranean Environment Under Limited Energy Inputs

Directory of Open Access Journals (Sweden)

Antonio Sergio De Franchi

2010-10-01

Full Text Available The aim of this work is comparing the two year performance (diameter, total height and mortality of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter. Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa, Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing. Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants. Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row. Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed

Short Rotation Forestry (SRF in a Mediterranean Environment Under Limited Energy Inputs

Directory of Open Access Journals (Sweden)

Stella Lovelli

2010-12-01

Full Text Available The aim of this work is comparing the two year performance (diameter, total height and mortality of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter. Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa, Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing. Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants. Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row. Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed

Operative vaginal delivery in case of persistent occiput posterior position after manual rotation failure: a 6-month follow-up on pelvic floor function.

Science.gov (United States)

Guerby, Paul; Parant, Olivier; Chantalat, Elodie; Vayssiere, Christophe; Vidal, Fabien

2018-05-21

To compare the short- and long-term perineal consequences (at 6 months postpartum) and short-term neonatal consequences of instrumental rotation (IR) to those induced by assisted delivery (AD) in the occiput posterior (OP) position, in case of manual rotation failure. A prospective observational cohort study; tertiary referral hospital including all women presenting with persistent OP position who delivered vaginally after manual rotation failure with attempted IR or AD in OP position from September 2015 to October 2016. Maternal and neonatal outcomes of all attempted IR deliveries were compared with OP operative vaginal deliveries. Main outcomes measured were pelvic floor function at 6 months postpartum including Wexner score for anal incontinence and ICIQ-FLUTS for urinary symptoms. Perineal morbidity comprised severe perineal tears, corresponding to third and fourth degree lacerations. Fetal morbidity parameters comprised low neonatal Apgar scores, acidaemia, major and minor fetal injuries and neonatal intensive care unit admissions. Among 5265 women, 495 presented with persistent OP positions (9.4%) and 111 delivered after manual rotation failure followed by AD delivery: 58 in the IR group and 53 in the AD in OP group. The incidence of anal sphincter injuries was significantly reduced after IR attempt (1.7% vs. 24.5%; p < 0.001) without increasing neonatal morbidity. At 6 months postpartum, AD in OP position was associated with higher rate of anal incontinence (30% vs. 5.5%, p = 0.001) and with more urinary symptoms, dyspareunia and perineal pain. OP operative deliveries are associated with significant perineal morbidity and pelvic floor dysfunction at 6 months postpartum.

Heat transfer enhancement with condensation by surface rotation

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, L L; Khrolenok, V V [A.V. Luikov Heat and Mass Transfer Inst., Minsk (Belarus)

1993-11-01

Process intensification relies on many unit operations on enhanced heat transfer. One technique for the enhancement of condensation heat transfer is the use of surface rotation. This is particularly effective in reducing the condensate film thickness. The formulae and relationships given in this paper are concerned with rotating discs and tubes, and can be used for developing advanced heat exchanger concepts. (Author)

Postoperative stiff shoulder after open rotator cuff repair: a 3- to 20-year follow-up study.

Science.gov (United States)

Vastamäki, H; Vastamäki, M

2014-12-01

Stiffness after a rotator cuff tear is common. So is stiffness after an arthroscopic rotator cuff repair. In the literature, however, postoperative restriction of passive range of motion after open rotator cuff repair in shoulders with free passive range of motion at surgery has seldom been recognized. We hypothesize that this postoperative stiffness is more frequent than recognized and slows the primary postoperative healing after a rotator cuff reconstruction. We wondered how common is postoperative restriction of both active and passive range of motion after open rotator cuff repair in shoulders with free passive preoperative range of motion, how it recovers, and whether this condition influences short- and long-term results of surgery. We also explored factors predicting postoperative shoulder stiffness. We retrospectively identified 103 postoperative stiff shoulders among 416 consecutive open rotator cuff repairs, evaluating incidence and duration of stiffness, short-term clinical results and long-term range of motion, pain relief, shoulder strength, and functional results 3-20 (mean 8.7) years after surgery in 56 patients. The incidence of postoperative shoulder stiffness was 20%. It delayed primary postoperative healing by 3-6 months and resolved during a mean 6.3 months postoperatively. External rotation resolved first, corresponding to that of the controls at 3 months; flexion and abduction took less than 1 year after surgery. The mean summarized range of motion (flexion + abduction + external rotation) increased as high as 93% of the controls' range of motion by 6 months and 100% by 1 year. Flexion, abduction, and internal rotation improved to the level of the contralateral shoulders as did pain, strength, and function. Age at surgery and condition of the biceps tendon were related to postoperative stiffness. Postoperative stiff shoulder after open rotator cuff repair is a common complication resolving in 6-12 months with good long-term results. © The

Ageing dynamics of translational and rotational diffusion in a colloidal glass

International Nuclear Information System (INIS)

Jabbari-Farouji, Sara; Eiser, Erika; Wegdam, Gerard H; Bonn, Daniel

2004-01-01

We study the dynamics of translational and rotational diffusion during the ageing of a colloidal glass of Laponite using polarized and depolarized dynamic light scattering. The dynamics are qualitatively similar between the two degrees of freedom. The short-time diffusion is independent of the time elapsed since the sample preparation. The intermediate- and long-time diffusion, on the other hand, slows down by several orders of magnitude during the ageing. The slowing down of the rotational diffusion is found to be much faster than that of the translational diffusion. (letter to the editor)

Training echo state networks for rotation-invariant bone marrow cell classification.

Science.gov (United States)

Kainz, Philipp; Burgsteiner, Harald; Asslaber, Martin; Ahammer, Helmut

2017-01-01

The main principle of diagnostic pathology is the reliable interpretation of individual cells in context of the tissue architecture. Especially a confident examination of bone marrow specimen is dependent on a valid classification of myeloid cells. In this work, we propose a novel rotation-invariant learning scheme for multi-class echo state networks (ESNs), which achieves very high performance in automated bone marrow cell classification. Based on representing static images as temporal sequence of rotations, we show how ESNs robustly recognize cells of arbitrary rotations by taking advantage of their short-term memory capacity. The performance of our approach is compared to a classification random forest that learns rotation-invariance in a conventional way by exhaustively training on multiple rotations of individual samples. The methods were evaluated on a human bone marrow image database consisting of granulopoietic and erythropoietic cells in different maturation stages. Our ESN approach to cell classification does not rely on segmentation of cells or manual feature extraction and can therefore directly be applied to image data.

Effect of rotation on Jeans instability of magnetized radiative quantum plasma

Science.gov (United States)

Joshi, H.; Pensia, R. K.

2017-03-01

The influence of rotation on the Jeans instability of homogeneous magnetized radiative quantum plasma is investigated. The basic equations of the problem are constructed and linearized by using the Quantum Magnetohydrodynamics (QMHD) model. The general dispersion relation is obtained by using the normal mode analysis technique, which is reduced for both the transverse and the longitudinal mode of propagations and further it is reduced for the axis of rotation parallel and perpendicular to the magnetic field. We found that the stabilizing effects of rotation are decreases for a strong magnetic field which is shown in the graphical representation. We also found that the quantum correction modified the condition of Jeans instability in both modes of propagation. The stabilizing effect of rotation is more increased in the presence of quantum correction.

GF-GC Theory of Human Cognition: Differentiation of Short-Term Auditory and Visual Memory Factors.

Science.gov (United States)

McGhee, Ron; Lieberman, Lewis

1994-01-01

Study sought to determine whether separate short-term auditory and visual memory factors would emerge given a sufficient number of markers in a factor matrix. A principal component factor analysis with varimax rotation was performed. Short-term visual and short-term auditory memory factors emerged as expected. (RJM)

Rotating flow

CERN Document Server

Childs, Peter R N

2010-01-01

Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

Influence of litter quality and fertilization on microbial nitrogen transformations in short-rotation forests

Energy Technology Data Exchange (ETDEWEB)

Slapokas, T

1991-01-01

Microbial decomposition of different types of litters in short-rotation forests was studied using the litter-bag technique. The impact of earthworm activity on leaf decomposition was included in one study and fungal succession was recorded in certain willow leaf litters. Soil fertility affected leaf compositions, which in turn influenced decomposition rates. Contents of macroelements, (esp. N), water-soluble and lingnified substances, and tannins (i.e. astringency) were observed during decomposition. Directly after leaf-fall most litters lost 5-27 per cent of their dry weight, mainly trough leaching. Thereafter, the various litters converged regarding their contents of certain leaf constituents, e.g. water-soluble and lignified substances and potassium. Mineral-nutrient loss rates from litters were often positively related to initial nutrient contents; in fact, N was transported into N-poor litters. N-contents increased until net mineralization began. Decomposition and N-transformations in a low-humified peat were followed at a cultivated bog. Mean decomposition in a drained, rotovated, and limed control plot was 2.6 per cent yr{sup -1}. Rates in fertilized plots were not shown to be higher, even though their bulk density and degree of humification had increased. N-mineralization rates in planted plot increase over the years. Pools of ammonium- and nitrate-N were lowest during periods of rapid plant growth. Nitrification occurred in both field and laboratory incubations of peat. In the top 10 cm of peat in plots receiving fixed N only, immobilization in 7-year-old stands was 53 kg N ha{sup -1} yr{sup -1}, whereas it was lower in liquid-N fertilized plots. Much of this fertilizer-N (ca. 1500 kg ha{sup -1} over 7 years) must have been immobilized in deeper peat layers or lost, partly through denitrification. One-year N-budgets are presented for alder stands with and without added fertilizer-N. (au).

Water use of a multigenotype poplar short-rotation coppice from tree to stand scale.

Science.gov (United States)

Bloemen, Jasper; Fichot, Régis; Horemans, Joanna A; Broeckx, Laura S; Verlinden, Melanie S; Zenone, Terenzio; Ceulemans, Reinhart

2017-02-01

Short-rotation coppice (SRC) has great potential for supplying biomass-based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar ( Populus ) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand-level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow ( F s ) measurements on individual plants vs. stand scale eddy covariance flux data during a 39-day intensive field campaign in late summer 2011. Daily stem diameter variation (∆ D ) was monitored simultaneously with F s to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆ D (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

Short Rotations in Forest Plantations Accelerate Virulence Evolution in Root-Rot Pathogenic Fungi

Directory of Open Access Journals (Sweden)

Jean-Paul Soularue

2017-06-01

Full Text Available As disease outbreaks in forest plantations are causing concern worldwide, a clear understanding of the influence of silvicultural practices on the development of epidemics is still lacking. Importantly, silvicultural practices are likely to simultaneously affect epidemiological and evolutionary dynamics of pathogen populations. We propose a genetically explicit and individual-based model of virulence evolution in a root-rot pathogenic fungus spreading across forest landscapes, taking the Armillaria ostoyae–Pinus pinaster pathosystem as reference. We used the model to study the effects of rotation length on the evolution of virulence and the propagation of the fungus within a forest landscape composed of even-aged stands regularly altered by clear-cutting and thinning operations. The life cycle of the fungus modeled combines asexual and sexual reproduction modes, and also includes parasitic and saprotrophic phases. Moreover, the tree susceptibility to the pathogen is primarily determined by the age of the stand. Our simulations indicated that the shortest rotation length accelerated both the evolution of virulence and the development of the epidemics, whatever the genetic variability in the initial fungal population and the asexuality rate of the fungal species

Do benefits accrue from longer rotations for students in Rural Clinical Schools?

Science.gov (United States)

Denz-Penhey, Harriet; Shannon, Susan; Murdoch, Campbell J; Newbury, Jonathon W

2005-01-01

The Australian Government has provided funding for Rural Clinical Schools (RCS) to provide substantial rural clinical experience to medical students. The strategy aims to acculturate students into rural living with the intended long-term outcome of increasing the availability and viability of rural health services. When evaluators from two of the Rural Clinical Schools discussed findings and insights relating to rural rotations from their in-depth evaluation studies of their respective schools they found a range of similarities. This article is a collaboration that articulates parallel findings from evaluations over 2 years, using three different approaches to students' placements across the two RCS: (1) students based long term in one centre (with only a few days away at a time); (2) students based long term in one centre with short-term rotations of 3-6 weeks away from home base; and (3) week rotations without a home base. The two RCS, as part of their initial establishment, put comprehensive internal evaluation processes in place, including the employment of dedicated evaluators extant from the teaching and assessment of the rural medical curriculum. Data were collected and analysed according to standard education evaluation procedures. Home-base preference: most students preferred having a home base in one centre and having as little time as possible away from that centre, while recognising that sometimes the requirement to go and learn elsewhere was useful. The reasons for this were three-fold: academic, clinical and social. Academic benefits: students enjoyed the excellence of teaching and learning opportunities in their rural sites and did not want their discipline of learning interrupted by what they perceived as unnecessary change. Students with a home base used their learning opportunities qualitatively differently from those students who had 6 week rotations. Their learning became self-directed and students sought opportunities to extend and consolidate

Short vowel placements in RP past and present

DEFF Research Database (Denmark)

Fabricius, Anne

This study addresses diachronic change in the short vowel system of RP. While TRAP lowering and backing in RP has been reported previously, the movements STRUT has undergone have proven more difficult to determine. This study identifies a TRAP/STRUT 'rotation' using acoustic measurements...

The GLAaS algorithm for portal dosimetry and quality assurance of RapidArc, an intensity modulated rotational therapy

International Nuclear Information System (INIS)

Nicolini, Giorgia; Vanetti, Eugenio; Clivio, Alessandro; Fogliata, Antonella; Korreman, Stine; Bocanek, Jiri; Cozzi, Luca

2008-01-01

To expand and test the dosimetric procedure, known as GLAaS, for amorphous silicon detectors to the RapidArc intensity modulated arc delivery with Varian infrastructures and to test the RapidArc dosimetric reliability between calculation and delivery. The GLAaS algorithm was applied and tested on a set of RapidArc fields at both low (6 MV) and high (18 MV) beam energies with a PV-aS1000 detector. Pilot tests for short arcs were performed on a 6 MV beam associated to a PV-aS500. RapidArc is a novel planning and delivery method in the category of intensity modulated arc therapies aiming to deliver highly modulated plans with variable MLC shapes, dose rate and gantry speed during rotation. Tests were repeated for entire (360 degrees) gantry rotations on composite dose plans and for short partial arcs (of ~6 or 12 degrees) to assess GLAaS and RapidArc mutual relationships on global and fine delivery scales. The gamma index concept of Low and the Modulation Index concept of Webb were applied to compare quantitatively TPS dose matrices and dose converted PV images. The Gamma Agreement Index computed for a Distance to Agreement of 3 mm and a Dose Difference (ΔD) of 3% was, as mean ± 1 SD, 96.7 ± 1.2% at 6 MV and 94.9 ± 1.3% at 18 MV, over the field area. These findings deteriorated slightly is ΔD was reduced to 2% (93.4 ± 3.2% and 90.1 ± 3.1%, respectively) and improved with ΔD = 4% (98.3 ± 0.8% and 97.3 ± 0.9%, respectively). For all tests a grid of 1 mm and the AAA photon dose calculation algorithm were applied. The spatial resolution of the PV-aS1000 is 0.392 mm/pxl. The Modulation Index for calculations resulted 17.0 ± 3.2 at 6 MV and 15.3 ± 2.7 at 18 MV while the corresponding data for measurements were: 18.5 ± 3.7 and 17.5 ± 3.7. Partial arcs findings were (for ΔD = 3%): GAI = 96.7 ± 0.9% for 6° rotations and 98.0 ± 1.1% for 12° rotations. The GLAaS method can be considered as a valid Quality Assurance tool for the verification of RapidArc fields

An Elongated Leading Edge Facilitates Rotation Flap Closure: In Vivo Demonstration.

Science.gov (United States)

Lichon, Vanessa; Barbosa, Naiara; Gomez, Doug; Goldman, Glenn

2016-01-01

Variation in the design of a rotation flap may affect wound closure tension. Lengthening the leading edge of a rotation flap has been a method of reducing the tension of closure in the primary motion. An in vitro study negating this tenant has been published. The authors set out to design an in vivo experiment to determine if lengthening the leading edge of a rotation flap has the effect of reducing closure tension in the primary motion of the repair. An animal study approved by Institutional Animal Care and Use Committee was undertaken in a pig model. A tension-measuring apparatus was designed using Teflon-coated wires and digital tensiometers. Rotation flaps of a standard design and with elongated leading edges were incised on the flanks of pigs under general anesthesia. Flap closure tensions were measured at points along the leading edge of the flap and in the secondary motion. Elongating the leading edge of a flap led to a statistically significant reduction in closure tension in the primary motion of the flap and at the flap tip. The secondary motion closure tensions were essentially unaffected. The authors confirm that elongating the leading edge of a standard rotation flap will reduce closure tension in the primary flap motion.

Energy sensitivity and variability analysis of Populus hybrid short-rotation plantations in northeastern United States. Final report

Energy Technology Data Exchange (ETDEWEB)

Bowersox, T.W.; Blankenhorn, P.R.

1979-10-24

Production of biomass by corn-like plantations has been demonstrated by a number of researchers. These forest analogs of agronomic cropping systems have the potential to yield substantially more biomass per unit area than traditional forests. Care is needed in choosing the appropriate sites, species, spacing, and harvesting strategies. Opportunities for increased yields have been suggested for fertilization and irrigation. Utilization of the biomass from these dense plantations for energy was the focus of this study. Although the amount of energy potential of the biomass is important, the energy output must be greater than the energy input for biomass to have a positive benefit to society. Further, in order to completely evaluate the net energy of the system it is necessary to examine the energy out-to-in ratios on the basis of usable energy (for example, usable heat, process steam and electricity), as well as all of the energies expended in producing, harvesting, transporting and processing the biomass. The objective of this study is to establish and analyze the energy inputs for selected management strategies in order to evaluate the sensitivity and variability of the energy inputs in the net energy analysis, and based on the net energy analysis to recommend a management strategy that minimizes energy inputs while maximizing biomass yield for short-rotation systems of Populus spp. in the northeastern United States.

GAROS, an aeroelastic code for coupled fixed-rotating structures

Energy Technology Data Exchange (ETDEWEB)

Rees, M. [Aerodyn Energiestyseme GmbH, Rendsburg (Germany); Vollan, A. [Pilatus Flugzeugwerke, Stans (Switzerland)

1996-09-01

The GAROS (General Analysis of Rotating Structures) program system has been specially designed to calculate aeroelastic stability and dynamic response of horizontal axis wind energy converters. Nevertheless it is also suitable for the dynamic analysis of helicopter rotors and has been used in the analysis of car bodies taking account of rotating wheels. GAROS was developed over the last 17 years. In the following the mechanical and the aerodynamic model will be discussed in detail. A short overview of the solution methods for the equation of motion in time and frequency domain will ge given. After this one example for the FEM model of the rotor and tower will be discussed. (EG)

The metastable dynamo model of stellar rotational evolution

International Nuclear Information System (INIS)

Brown, Timothy M.

2014-01-01

This paper introduces a new empirical model for the rotational evolution of Sun-like stars—those with surface convection zones and non-convective interior regions. Previous models do not match the morphology of observed (rotation period)-color diagrams, notably the existence of a relatively long-lived 'C-sequence' of fast rotators first identified by Barnes. This failure motivates the Metastable Dynamo Model (MDM) described here. The MDM posits that stars are born with their magnetic dynamos operating in a mode that couples very weakly to the stellar wind, so their (initially very short) rotation periods at first change little with time. At some point, this mode spontaneously and randomly changes to a strongly coupled mode, the transition occurring with a mass-dependent lifetime that is of the order of 100 Myr. I show that with this assumption, one can obtain good fits to observations of young clusters, particularly for ages of 150-200 Myr. Previous models and the MDM both give qualitative agreement with the morphology of the slower-rotating 'I-sequence' stars, but none of them have been shown to accurately reproduce the stellar-mass-dependent evolution of the I-sequence stars, especially for clusters older than a few hundred million years. I discuss observational experiments that can test aspects of the MDM, and speculate that the physics underlying the MDM may be related to other situations described in the literature, in which stellar dynamos may have a multi-modal character.

Global rotation

International Nuclear Information System (INIS)

Rosquist, K.

1980-01-01

Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

Inception mechanism and suppression of rotating stall in an axial-flow fan

International Nuclear Information System (INIS)

Nishioka, T

2013-01-01

Inception patterns of rotating stall at two stagger-angle settings for the highly loaded rotor blades were experimentally investigated in a low-speed axial-flow fan. Rotor-tip flow fields were also numerically investigated to clarify the mechanism behind the rotating stall inception. The stall inception patterns depended on the rotor stagger-angle settings. The stall inception from a rotating instability was confirmed at the design stagger-angle settings. The stall inception from a short length-scale stall cell (spike) was also confirmed at the small stagger-angle setting. The spillage of tip-leakage flow and the tip-leakage vortex breakdown influence the rotating stall inception. An air-separator has been developed based on the clarified inception mechanism of rotating stall. The rotating stall was suppressed by the developed air-separator, and the operating range of fan was extended towards low flow rate. The effect of developed air-separator was also confirmed by application to a primary air fan used in a coal fired power plant. It is concluded from these results that the developed air-separator can provide a wide operating range for an axial-flow fan

Swings between rotation and accretion power in a binary millisecond pulsar.

Science.gov (United States)

Papitto, A; Ferrigno, C; Bozzo, E; Rea, N; Pavan, L; Burderi, L; Burgay, M; Campana, S; Di Salvo, T; Falanga, M; Filipović, M D; Freire, P C C; Hessels, J W T; Possenti, A; Ransom, S M; Riggio, A; Romano, P; Sarkissian, J M; Stairs, I H; Stella, L; Torres, D F; Wieringa, M H; Wong, G F

2013-09-26

It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron star's rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.

Improper trunk rotation sequence is associated with increased maximal shoulder external rotation angle and shoulder joint force in high school baseball pitchers.

Science.gov (United States)

Oyama, Sakiko; Yu, Bing; Blackburn, J Troy; Padua, Darin A; Li, Li; Myers, Joseph B

2014-09-01

In a properly coordinated throwing motion, peak pelvic rotation velocity is reached before peak upper torso rotation velocity, so that angular momentum can be transferred effectively from the proximal (pelvis) to distal (upper torso) segment. However, the effects of trunk rotation sequence on pitching biomechanics and performance have not been investigated. The aim of this study was to investigate the effects of trunk rotation sequence on ball speed and on upper extremity biomechanics that are linked to injuries in high school baseball pitchers. The hypothesis was that pitchers with improper trunk rotation sequence would demonstrate lower ball velocity and greater stress to the joint. Descriptive laboratory study. Three-dimensional pitching kinematics data were captured from 72 high school pitchers. Subjects were considered to have proper or improper trunk rotation sequences when the peak pelvic rotation velocity was reached either before or after the peak upper torso rotation velocity beyond the margin of error (±3.7% of the time from stride-foot contact to ball release). Maximal shoulder external rotation angle, elbow extension angle at ball release, peak shoulder proximal force, shoulder internal rotation moment, and elbow varus moment were compared between groups using independent t tests (α ways that may influence injury risk. As such, exercises that reinforce the use of a proper trunk rotation sequence during the pitching motion may reduce the stress placed on the structures around the shoulder joint and lead to the prevention of injuries. © 2014 The Author(s).

Spinning rate decay of levitated high-Tc superconductors in rotational magnetic field

Energy Technology Data Exchange (ETDEWEB)

Terentiev, A.N.; Kutukova, E.O.; Kuznetsov, A.A. (Inst. of Chemical Physics, Academy of Sciences, Moscow (Russia)); Mozhaev, A.P. (Moscow State Univ., Dept. of Chemistry (Russia))

1992-04-01

The rotation damping of a levitated superconductor was examined in the static field of a ring-shaped magnet and in the rotating field of coils. It was demonstrated that the pinning force mainly contributed to magnetic friction while the influence of a viscous component was negligible. The rotating magnetic field created a torque, reducing the angular deceleration under relaxation. Dependence of the rotational field-induced torque on the field-intensity was step-like. A relationship between the step-like behavior of rotational field-induced torque and pinning center distribution is discussed. The origins of friction torque and rotational field-produced torque are discussed. (orig.).

Emergent rotational symmetries in disordered magnetic domain patterns.

Science.gov (United States)

Su, Run; Seu, Keoki A; Parks, Daniel; Kan, Jimmy J; Fullerton, Eric E; Roy, Sujoy; Kevan, Stephen D

2011-12-16

Uniaxial systems often form labyrinthine domains that exhibit short-range order but are macroscopically isotropic and would not be expected to exhibit precise symmetries. However, their underlying frustration results in a multitude of metastable configurations of comparable energy, and driving such a system externally might lead to pattern formation. We find that soft x-ray speckle diffraction patterns of the labyrinthine domains in CoPd/IrMn heterostructures reveal a diverse array of hidden rotational symmetries about the magnetization axis, thereby suggesting an unusual form of emergent order in an otherwise disordered system. These symmetries depend on applied magnetic field, magnetization history, and scattering wave vector. Maps of rotational symmetry exhibit intriguing structures that can be controlled by manipulating the applied magnetic field in concert with the exchange bias condition. © 2011 American Physical Society

EBR-II rotating plug seal maintenance

International Nuclear Information System (INIS)

Allen, K.J.

1986-01-01

The EBR-II rotating plug seals require frequent cleaning and maintenance to keep the plugs from sticking during fuel handling. Time consuming cleaning on the cover gas and air sides of the dip ring seal is required to remove oxidation and sodium reaction products that accumulate and stop plug rotation. Despite severely limited access, effective seal cleaning techniques have removed 11 800 lb (5 352 kg) of deposits from the seals since 1964. Temperature control modifications and repairs have also required major maintenance work. Suggested seal design recommendations could significantly reduce maintenance on future similar seals

Energy wood production in short rotation. Opportunities and problems in their implementation. An analysis involving expert interviews; Energieholzproduktion im Kurzumtrieb. Chancen und Probleme bei ihrer Umsetzung. Eine Analyse unter Einbeziehung von Experteninterviews

Energy Technology Data Exchange (ETDEWEB)

Wirkner, Ronny

2010-12-01

The thesis has to the content the latest stand and the possibilities of further development of wood energy production by short rotation coppice (SRC). After analyzing the development of this relatively new option of the management of fast growing tree species and their possibilities, the associated legal bases are being analyzed. In addition to related agricultural land, other options will be considered to establish land (forest, fallow land). Weaknesses in delimitation and promotion, especially at country level are discussed. There follows a detailed consideration of the economical and ecological contemplation of wood agricultural cultivation, as well as the basics of the management including the raw material supply. The analyzed results serve as a basis for running interviews with experts of the subject fast growing tree species. The results of the interviews show that SRC mainly as an opportunity for long-term wood energy supply and establishment of regional circuits is seen with emphasis on the agricultural sector, but in this context there are lots of deficits on side of the management technology, basic conditions and other establishment barriers that we are confront with. After overcoming the remaining start-up difficulties however the chances are good to expand the energy wood production in short rotation forestry in an economically viable, ecologically profitable and socially acceptable way and therewith contribute to the diversification of agricultural production and relief of multifunctional forest management. (orig.)

Can Rotational Atherectomy Cause Thermal Tissue Damage? A Study of the Potential Heating and Thermal Tissue Effects of a Rotational Atherectomy Device

International Nuclear Information System (INIS)

Gehani, Abdurrazzak A.; Rees, Michael R.

1998-01-01

Purpose: Thermal tissue damage (TTD) is customarily associated with some lasers. The thermal potential of rotational atherectomy (RA) devices is unknown. We investigated the temperature profile and potential TTD as well as the value of fluid flushing of an RA device. Methods: We used a high-resolution infrared imaging system that can detect changes as small as 0.1 deg. C to measure the temperature changes at the tip of a fast RA device with and without fluid flushing. To assess TTD, segments of porcine aorta were subjected to the rotating tip under controlled conditions, stained by a special histochemical stain (picrisirius red) and examined under normal and polarized light microscopy. Results: There was significant heating of the rotating cam. The mean 'peak' temperature rise was 52.8 ± 16.9 deg. C. This was related to rotational speed; thus the 'peak' temperature rise was 88.3 ± 12.6 deg. C at 80,000 rpm and 17.3 ± 3.8 deg. C at 20,000 rpm (p < 0.001, t-test). Fluid flushing at 18 ml/min reduced, but did not abolish, heating of the device (11.8 ± 2.9 deg. C). A crater was observed in all segments exposed to the rotating tip. The following features were most notable: (i) A zone of 'thermal' tissue damage extended radially from the crater reaching adventitia in some sections, especially at high speeds. This zone showed markedly reduced or absent birefringence. (ii) Fluid flushing of the catheter reduced the above changes but increased the incidence and extent of dissections in the media, especially when combined with high atherectomy speeds. (iii) These changes were observed in five of six specimens exposed to RA without flushing, but in only one of six with flushing (p < 0.05). (iv) None of the above changes was seen in control segments. Conclusion: RA is capable of generating significant heat and potential TTD. Fluid flushing reduced heating and TTD. These findings warrant further studies in vivo, and may influence the design of atherectomy devices

On the Rotating and Oscillating strings in $(AdS_3\\times S^3)_{\\varkappa}$

CERN Document Server

Banerjee, Aritra

2014-01-01

We study rigidly rotating strings in the $\\varkappa$-deformed $AdS_3 \\times S^3$ background. We find out two classes of solutions corresponding to the giant magnon and single spike solutions of the string rotating is two $S^2_{\\varkappa}$ subspace of rotations reduced along two different isometries. We verify that the dispersion relations reduce to the well known relation in the $\\varkappa\\rightarrow 0$ limit. We further study some oscillating string solutions in the $S^3_{\\varkappa}$ subspace.

Rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation

Energy Technology Data Exchange (ETDEWEB)

Teshima, Hidekazu [Nippon Steel Corp., Kawasaki, Kanagawa (Japan). Advanced Materials and Technology Research Labs.; Tawara, Taichi; Shimada, Ryuichi

1997-08-01

This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

Electro-mechanical coupling of rotating 3D beams

Directory of Open Access Journals (Sweden)

Stoykov S.

2016-01-01

Full Text Available A rotating thin-walled beam with piezoelectric element is analysed. The beam is considered to vibrate in space, hence the longitudinal, transverse and torsional deformations are taken into account. The bending deformations of the beam are modelled by assuming Timoshenko's theory. Torsion is included by considering that the cross section rotates as a rigid body but can deform in longitudinal direction due to warping. The warping function is computed preliminary by the finite element method. The equation of motion is derived by the principle of virtual work and discretized in space by the Ritz method. Electro-mechanical coupling is included in the model by considering the internal electrical energy and the electric charge output. The piezo-electric constitutive relations are used in reduced form. The beam is assumed to rotate about a fixed axis with constant speed. The equation of motion is derived in rotating coordinate system, but the influence of the rotation of the coordinate system is taken into account through the inertia forces. Results in time domain are presented for different speeds of rotation and frequencies of vibration. The influence of the speed of rotation and of the frequency of vibration on the electrical output is presented and analysed.

Effects of Increased Nitrogen Deposition and Rotation Length on Long-Term Productivity of Cunninghamia lanceolata Plantation in Southern China

Science.gov (United States)

Zhao, Meifang; Xiang, Wenhua; Tian, Dalun; Deng, Xiangwen; Huang, Zhihong; Zhou, Xiaolu; Peng, Changhui

2013-01-01

Cunninghamia lanceolata (Lamb.) Hook. has been widely planted in subtropical China to meet increasing timber demands, leading to short-rotation practices that deplete soil nutrients. However, increased nitrogen (N) deposition offsets soil N depletion. While long-term experimental data investigating the coupled effects related to short rotation practices and increasing N deposition are scarce, applying model simulations may yield insights. In this study, the CenW3.1 model was validated and parameterized using data from pure C. lanceolata plantations. The model was then used to simulate various changes in long-term productivity. Results indicated that responses of productivity of C. lanceolata plantation to increased N deposition were more related to stand age than N addition, depending on the proportion and age of growing forests. Our results have also shown a rapid peak in growth and N dynamics. The peak is reached sooner and is higher under higher level of N deposition. Short rotation lengths had a greater effect on productivity and N dynamics than high N deposition levels. Productivity and N dynamics decreased as the rotation length decreased. Total productivity levels suggest that a 30-year rotation length maximizes productivity at the 4.9 kg N ha−1 year−1 deposition level. For a specific rotation length, higher N deposition levels resulted in greater overall ecosystem C and N storage, but this positive correlation tendency gradually slowed down with increasing N deposition levels. More pronounced differences in N deposition levels occurred as rotation length decreased. To sustain C. lanceolata plantation productivity without offsite detrimental N effects, the appropriate rotation length is about 20–30 years for N deposition levels below 50 kg N ha−1 year−1 and about 15–20 years for N deposition levels above 50 kg N ha−1 year−1. These results highlight the importance of assessing N effects on carbon management and the long-term productivity of

Water requirements of short rotation poplar coppice: Experimental and modelling analyses across Europe

Czech Academy of Sciences Publication Activity Database

Fischer, Milan; Zenone, T.; Trnka, Miroslav; Orság, Matěj; Montagnani, L.; Ward, E. J.; Tripathi, Abishek; Hlavinka, Petr; Seufert, G.; Žalud, Zdeněk; King, J.; Ceulemans, R.

2018-01-01

Roč. 250, MAR (2018), s. 343-360 ISSN 0168-1923 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : energy-balance closure * dual crop coefficient * radiation use efficiency * simulate yield response * below-ground carbon * vs. 2nd rotation * flux data * biomass production * forest model * stand-scale * Bioenergy * Bowen ratio and energy balance * Crop coefficient * Eddy covariance * Evapotranspiration * Water balance Subject RIV: GC - Agronomy OBOR OECD: Agriculture Impact factor: 3.887, year: 2016

A Microscopic Quantal Model for Nuclear Collective Rotation

International Nuclear Information System (INIS)

Gulshani, P.

2007-01-01

A microscopic, quantal model to describe nuclear collective rotation in two dimensions is derived from the many-nucleon Schrodinger equation. The Schrodinger equation is transformed to a body-fixed frame to decompose the Hamiltonian into a sum of intrinsic and rotational components plus a Coriolis-centrifugal coupling term. This Hamiltonian (H) is expressed in terms of space-fixed-frame particle coordinates and momenta by using commutator of H with a rotation angle. A unified-rotational-model type wavefunction is used to obtain an intrinsic Schrodinger equation in terms of angular momentum quantum number and two-body operators. A Hartree-Fock mean-field representation of this equation is then obtained and, by means of a unitary transformation, is reduced to a form resembling that of the conventional semi-classical cranking model when exchange terms and intrinsic spurious collective excitation are ignored

An Investigation of the Impact of an Intervention to Reduce Academic Procrastination Using Short Message Service (SMS) Technology

Science.gov (United States)

Davis, Darrel R.; Abbitt, Jason T.

2013-01-01

This mixed-method pilot study investigated the impact of a custom Short Message Service (SMS) reminder system developed to help students reduce procrastination and increase performance on weekly content-related quizzes in a high-enrollment hybrid online course. Text message reminders were sent to three students with high procrastination and low…

Current Biomechanical Concepts of Suture Bridge Repair Technique for Rotator Cuff Tear

OpenAIRE

Ming-Long Yeh; Chih-Kai Hong; Wei-Ren Su; I-Ming Jou; Cheng-Li Lin; Chii-Jen Lin

2015-01-01

Rotator cuff tears are one of the most common disorders of the shoulder and can have significant effects on daily activities as a result of pain, loss of motion and strength. The goal of rotator cuff repair is aimed at anatomic restoration of the rotator cuff tendon to reduce pain and improve the joint function. Recently, arthroscopic repair has been widely accepted for treatment of rotator cuff tears due to its equal or better results than those from open repair. In 2006, a...

Hydration and rotational diffusion of levoglucosan in aqueous solutions

Science.gov (United States)

Corezzi, S.; Sassi, P.; Paolantoni, M.; Comez, L.; Morresi, A.; Fioretto, D.

2014-05-01

Extended frequency range depolarized light scattering measurements of water-levoglucosan solutions are reported at different concentrations and temperatures to assess the effect of the presence and distribution of hydroxyl groups on the dynamics of hydration water. The anhydro bridge, reducing from five to three the number of hydroxyl groups with respect to glucose, considerably affects the hydration properties of levoglucosan with respect to those of mono and disaccharides. In particular, we find that the average retardation of water dynamics is ≈3-4, that is lower than ≈5-6 previously found in glucose, fructose, trehalose, and sucrose. Conversely, the average number of retarded water molecules around levoglucosan is 24, almost double that found in water-glucose mixtures. These results suggest that the ability of sugar molecules to form H-bonds through hydroxyl groups with surrounding water, while producing a more effective retardation, it drastically reduces the spatial extent of the perturbation on the H-bond network. In addition, the analysis of the concentration dependence of the hydration number reveals the aptitude of levoglucosan to produce large aggregates in solution. The analysis of shear viscosity and rotational diffusion time suggests a very short lifetime for these aggregates, typically faster than ≈20 ps.

Orientation illusions and heart-rate changes during short-radius centrifugation

NARCIS (Netherlands)

Hecht, H.; Kavelaars, J.; Cheung, C. C.; Young, L. R.

2001-01-01

Intermittent short-radius centrifugation is a promising countermeasure against the adverse effects of prolonged weightlessness. To assess the feasibility of this countermeasure, we need to understand the disturbing sensory effects that accompany some movements carried out during rotation. We tested

Object permanence in dogs: invisible displacement in a rotation task.

Science.gov (United States)

Miller, Holly C; Gipson, Cassie D; Vaughan, Aubrey; Rayburn-Reeves, Rebecca; Zentall, Thomas R

2009-02-01

Dogs were tested for object permanence using an invisible displacement in which an object was hidden in one of two containers at either end of a beam and the beam was rotated. Consistent with earlier research, when the beam was rotated 180 degrees , the dogs failed to find the object. However, when the beam was rotated only 90 degrees , they were successful. Furthermore, when the dogs were led either 90 degrees or 180 degrees around the apparatus, they were also successful. In a control condition, when the dogs could not see the direction of the 90 degrees rotation, they failed to find the object. The results suggest that the 180 degrees rotation may produce an interfering context that can be reduced by rotating the apparatus only 90 degrees or by changing the dogs' perspective. Once the conflict is eliminated, dogs show evidence of object permanence that includes invisibly displaced objects.

Inhibition of 5-LOX, COX-1, and COX-2 increases tendon healing and reduces muscle fibrosis and lipid accumulation after rotator cuff repair.

Science.gov (United States)

Oak, Nikhil R; Gumucio, Jonathan P; Flood, Michael D; Saripalli, Anjali L; Davis, Max E; Harning, Julie A; Lynch, Evan B; Roche, Stuart M; Bedi, Asheesh; Mendias, Christopher L

2014-12-01

The repair and restoration of function after chronic rotator cuff tears are often complicated by muscle atrophy, fibrosis, and fatty degeneration of the diseased muscle. The inflammatory response has been implicated in the development of fatty degeneration after cuff injuries. Licofelone is a novel anti-inflammatory drug that inhibits 5-lipoxygenase (5-LOX), as well as cyclooxygenase (COX)-1 and COX-2 enzymes, which play important roles in inducing inflammation after injuries. While previous studies have demonstrated that nonsteroidal anti-inflammatory drugs and selective inhibitors of COX-2 (coxibs) may prevent the proper healing of muscles and tendons, studies about bone and cartilage have demonstrated that drugs that inhibit 5-LOX concurrently with COX-1 and COX-2 may enhance tissue regeneration. After the repair of a chronic rotator cuff tear in rats, licofelone would increase the load to failure of repaired tendons and increase the force production of muscle fibers. Controlled laboratory study. Rats underwent supraspinatus release followed by repair 28 days later. After repair, rats began a treatment regimen of either licofelone or a vehicle for 14 days, at which time animals were euthanized. Supraspinatus muscles and tendons were then subjected to contractile, mechanical, histological, and biochemical analyses. Compared with controls, licofelone-treated rats had a grossly apparent decrease in inflammation and increased fibrocartilage formation at the enthesis, along with a 62% increase in the maximum load to failure and a 51% increase in peak stress to failure. Licofelone resulted in a marked reduction in fibrosis and lipid content in supraspinatus muscles as well as reduced expression of several genes involved in fatty infiltration. Despite the decline in fibrosis and fat accumulation, muscle fiber specific force production was reduced by 23%. The postoperative treatment of cuff repair with licofelone may reduce fatty degeneration and enhance the development

Physiological aspects of short-rotation culture of the poplar. Fertilization of soils by sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Haddad, G

1988-01-01

This study, on the poplar (Populus Trichocarpa x Populus deltoides, c.v. Raspalje) concerned two different problems. The first is a physiological study on the tree treated in short rotation; the second deals with a fertilization by sewage sludge and the consequences on the environment. We have carried out in the laboratory two complementary experiments, the one, on the culture of the poplar in hydroponic medium with a pollutant element (Hg), and the other in the potentialities of soil retention. In the first part, we have showed that: - the best period for coppicing is between Mid August and May, as soon as the stumps were four or five years-old, - the coppicing has a stimulating effect on the growth of the coppice shoots, - the mean number of dominant coppice shoots, after several coppicing, is two, - the productivity is about 20 to 30 tonnes of dry matter per hectare and per year. The second part of this study has showed that: - using 3.2 tonnes of dehydrated sewage sludge per hectare and per year to fertilize, has the same effects on productivity of poplars as a classical fertilization (every 5 years) by chemical manure (N, P, K), - there were no differences in the concentration of heavy metals (Cd, Cu, Pb and Hg), in the different parts of the poplars, between the different plots fertilized with sewage sludge, chemical manure and controlled. Moreover, the experiments performed, in the laboratory showed that: - pollutant elements (Cd, Cu) were fixed in the top of the column soil, - using a hydroponic solution containing a mercuric chloride, labelled ({sup 203}Hg), the poplars absorb very little of the pollutant element. Only 10% of the mercury in the solution was to be found in the plant and 99% of this in the root-system, more precisely, at the level epidermic barrier.

DETERMINATION OF CRITICAL ROTATIONAL SPEED OF CIRCULAR SAWS FROM NATURAL FREQUENCIES OF ANNULAR PLATE WITH ANALOGOUS DIMENSIONS

Directory of Open Access Journals (Sweden)

Ante Skoblar

2016-03-01

Full Text Available It is suitable to reduce thickness of circular saw when trying to enhance usability of wood raw material, but reducing thickness also causes reduction of permissible rotational speed which reduces sawing speed. If one increase circular saw rotational speed over permissible one the quality of machined surfaces will reduce because of enhanced vibrations. Permissible rotational speed can be calculated from critical rotational speed which can be defined from natural frequencies of the saw. In this article critical rotational speeds of standard clamped saws (with flat disk surface and without slots are calculated by using finite element method and classical theory of thin plates on annular plates. Mode shapes and natural frequencies of annular plates are determined by using Bessel functions and by using polynomial functions. Obtained results suggest that standard clamped circular saws without slots and with relatively small teeth can be determined from classical theory of thin plates for annular plates with accuracy depending on clamping ratio.

A rotation/magnetism analogy for the quark–gluon plasma

Energy Technology Data Exchange (ETDEWEB)

McInnes, Brett, E-mail: matmcinn@nus.edu.sg

2016-10-15

In peripheral heavy ion collisions, the Quark–Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.

Short rotation woody biomass production as option for the restoration of post-mining areas in lower Lusatia, Germany

Energy Technology Data Exchange (ETDEWEB)

Bohm, C.; Quinkenstein, A.; Freese, D. [Brandenburg Univ. of Technology, Cottbus (Germany). Soil Protection and Recultivation; Huttl, R.R. [Brandenburg Univ. of Technology, Cottbus (Germany). Soil Protection and Recultivation; GFZ German Research Centre for Geosciences, Potsdam (Germany)

2010-07-01

Reclaimed mine sites in the Lusatian lignite-mining district in Germany are characterized by low annual precipitation and marginal soils. As such, crop yield is typically low and conventional land use systems fail in terms of reliable and efficient crop production. The production of woody biomass for bioenergy may be a promising alternative to improve soil fertility and also to enhance the economic value of these post-mining areas. Previous studies have shown that black locust (Robinia pseudoacacia L.) may be a suitable tree species for this purpose. This paper evaluated the ecological and economic benefits of producing woody biomass in short rotation coppices (SRC) and alley cropping systems (ACS) with black locust. The results showed that compared to conventional agriculture, such land use is not very profitable due to high establishment and harvesting costs and the comparatively low prices for wood energy. However, because of the improved microclimate, the crop yield in ACS is higher than in conventional agriculture. The cultivation of black locust resulted in a higher humus accumulation and in a lower harvest-related nutrient export than the cultivation of alfalfa as a typical recultivation crop in this region. It was concluded SRC with black locust is more beneficial than conventional agriculture in terms of improving soil fertility in the degraded post-mining areas of Lower Lusatia.

Investigating the Magnetospheres of Rapidly Rotating B-type Stars

Science.gov (United States)

Fletcher, C. L.; Petit, V.; Nazé, Y.; Wade, G. A.; Townsend, R. H.; Owocki, S. P.; Cohen, D. H.; David-Uraz, A.; Shultz, M.

2017-11-01

Recent spectropolarimetric surveys of bright, hot stars have found that ~10% of OB-type stars contain strong (mostly dipolar) surface magnetic fields (~kG). The prominent paradigm describing the interaction between the stellar winds and the surface magnetic field is the magnetically confined wind shock (MCWS) model. In this model, the stellar wind plasma is forced to move along the closed field loops of the magnetic field, colliding at the magnetic equator, and creating a shock. As the shocked material cools radiatively it will emit X-rays. Therefore, X-ray spectroscopy is a key tool in detecting and characterizing the hot wind material confined by the magnetic fields of these stars. Some B-type stars are found to have very short rotational periods. The effects of the rapid rotation on the X-ray production within the magnetosphere have yet to be explored in detail. The added centrifugal force due to rapid rotation is predicted to cause faster wind outflows along the field lines, leading to higher shock temperatures and harder X-rays. However, this is not observed in all rapidly rotating magnetic B-type stars. In order to address this from a theoretical point of view, we use the X-ray Analytical Dynamical Magnetosphere (XADM) model, originally developed for slow rotators, with an implementation of new rapid rotational physics. Using X-ray spectroscopy from ESA's XMM-Newton space telescope, we observed 5 rapidly rotating B-types stars to add to the previous list of observations. Comparing the observed X-ray luminosity and hardness ratio to that predicted by the XADM allows us to determine the role the added centrifugal force plays in the magnetospheric X-ray emission of these stars.

Experimental occlusal interferences. Part IV. Mandibular rotations induced by a pliable interference.

Science.gov (United States)

Christensen, L V; Rassouli, N M

1995-11-01

In 12 subjects, a pliable, yet unbreakable, intercuspal interference (aluminum shim onlay splint; uniform height of 0.25 mm) was placed between either the right or left maxillary and mandibular second premolars and first molars. During brief and forceful biting (dynamic chewing stroke of about 20 kg force) the interference emulated a semisoft food bolus, and at the end of biting (subsequent static clenching stroke of about 20 kg force) it emulated a rigid metal interference. During dynamic/static biting, rotational electrognathography measured maximum frontal and horizontal plane torque of the right and left mandibular condyles. Eleven subjects (92%) showed frontal plane upward rotation (mean of 1.0 degree) of the condyle contralateral to the interference, and one subject (8%) showed frontal plane upward rotation (0.4 degree) of the condyle ipsilateral to the interference. Two subjects (17%) showed no horizontal plane rotation; seven subjects (58%) showed backward rotation (mean of 0.4 degree) of the condyle contralateral to the interference; and three subjects (25%) showed backward rotation (mean of 0.3 degree) of the condyle ipsilateral to the interference. It is suggested that, in the presence of an occlusal interference, mastication may have both short- and long-term detrimental effects.

Assessment of Rotationally-Invariant Clustering Using Streamlet Tractography

DEFF Research Database (Denmark)

Liptrot, Matthew George; Lauze, François

2016-01-01

We present a novel visualisation-based strategy for the assessment of a recently proposed clustering technique for raw DWI volumes which derives rotationally-invariant metrics to classify voxels. The validity of the division of all brain tissue voxels into such classes was assessed using the rece......We present a novel visualisation-based strategy for the assessment of a recently proposed clustering technique for raw DWI volumes which derives rotationally-invariant metrics to classify voxels. The validity of the division of all brain tissue voxels into such classes was assessed using...... the recently developed streamlets visualisation technique, which aims to represent brain fibres by collections of many short streamlines. Under the assumption that streamlines seeded in a cluster should stay within it, we were able to assess how well perceptual tracing could occur across the boundaries...... of the clusters....

Bunch rotation tests at SPS flat top for the AWAKE experiment

CERN Document Server

Argyropoulos, T; Bohl, T; Esteban Müller, J F; Petrenko, A; Shaposhnikova, E; Timko, H

2013-01-01

This note summarises the results of two MDs on bunch rotation at SPS flat top. The first MD was carried out on 11th July 2012 with the Q26 optics, while the second MD on the 30th October 2012 used the Q20 optics. To obtain a short bunch length, which is important for the plasma wake-field acceleration project AWAKE, the bunches have been rotated in longitudinal phase space on the SPS flat top. The aim of the MDs was to obtain first estimates of what bunch length, intensity, and transverse emittances - which are crucial for the project - can be achieved for high-intensity single bunches.

Theory of symmetry and of exact solution properties for fast rotating nuclei

International Nuclear Information System (INIS)

Heydon, B.

1995-01-01

We propose a study of rotating multi-fermionic systems. The method we developed is based on unitary group theory. The formalism of Gel'fand-Tsetlin is is simplified to binary calculations. With the help of operator of Casimir and physical interpretations using dichotomic symmetries (signature, parity), we show rotating Hamiltonians obey to a new quantum symmetry called P. The study of short range two-body interaction breaking weakly this symmetry, is made by using single j-shell. Nuclear interactions coupling two j-shell are introduced. This study allows us to compare ours results to experimental data for three isotopes of Zirconium. (author)

Spontaneous Formation of Anti-ferromagnetic Vortex Lattice in a Fast Rotating BEC with Dipole Interactions

International Nuclear Information System (INIS)

Yang Shijie; Feng Shiping; Wen Yuchuan; Yu Yue

2007-01-01

When a Bose-Einstein condensate is set to rotate, superfluid vortices will be formed, which finally condense into a vortex lattice as the rotation frequency further increases. We show that the dipole-dipole interactions renormalize the short-range interaction strength and result in a distinction between interactions of parallel-polarized atoms and interactions of antiparallel-polarized atoms. This effect may lead to a spontaneous breakdown of the rapidly rotating Bose condensate into a novel anti-ferromagnetic-like vortex lattice. The upward-polarized Bose condensate forms a vortex lattice, which is staggered against a downward-polarized vortex lattice. A phase diagram related to the coupling strength is obtained.

Rotating liquid blanket for a toroidal fusion reator

International Nuclear Information System (INIS)

Moir, R.W.

1987-01-01

A novel blanket concept is presented for toroidal geometry in which many of the limitations imposed by a first wall are avoided by not having a first wall in the usual sense. The blanket consists of a rapidly rotating, low-vapor-pressure liquid that has a sharp boundary with the vacuum region. Nozzles inject ja continuous layer of cool liquid on the inner surface. The noncentricity of the plasma is maintained so that the plasma scrape-off region intersects the rotating liqid in a localized region. This noncentricity allows sufficient space so that the scrape-off plasma layer will not bombard the nozzles, whch penetrate through the rotating liquid. This liquid ''first wall'' is bombarded by the plasma, resulting in heat deposition, sputtering, and evaporation during the short time before the exposed liquid is covered by fresh, cool liquid from the nozzles. The advantages of this reactor concept appear to be very high wall loadings (speculated to be over 10 MW/m 2 ) and long component lifetime, both crucial economic factors. The nozzles are designed for easy replacement. The reactor's disatvantage is its enormous potential for plasma contamination by impurities. (orig.)

Rotating strings in confining AdS/CFT backgrounds

International Nuclear Information System (INIS)

Armoni, Adi; Barbon, Jose L.F.; Petkou, Anastasios C.

2002-01-01

We study semiclassical rotating strings in AdS/CFT backgrounds that exhibit both confinement and finite-size effects. The energy versus spin dispersion relation for short strings is the expected Regge trajectory behaviour, with the same string tension as is measured by the Wilson loop. Long strings probe the interplay between confinement and finite-size effects. In particular, the dispersion relation for long strings shows a characteristic dependence on the string tension and the finite-size scale. (author)

Interfraction Prostate Rotation Determined from In-Room Computerized Tomography Images

International Nuclear Information System (INIS)

Owen, Rebecca; Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian

2011-01-01

Fiducial markers (FMs) are commonly used as a correction technique for interfraction translations of the prostate. The aim of this investigation was to determine the magnitude of prostate rotations using 2 methods: FM coordinates and the anatomical border of the prostate and rectum. Daily computed tomography (CT) scans (n = 346) of 10 prostate cancer patients with 3 implanted FMs were acquired using the CT on rails. FM coordinates were used to determine rotation in the sagittal, transverse, and coronal planes, and CT contours of the prostate and rectum were used to determine rotation along the sagittal plane. An adaptive technique based on a subset of images (n = 6; planning and first 5 treatment CTs) to reduce systematic rotation errors in the sagittal plane was tested. The standard deviation (SD) of systematic rotation from FM coordinates was 7.6 o , 7.7 o , and 5.0 o in the sagittal, transverse and coronal planes. The corresponding SD of random error was 10.2 o , 15.8 o , and 6.5 o . Errors in the sagittal plane, determined from prostate and rectal contours, were 10.1 o (systematic) and 7.7 o (random). These results did not correlate with rotation computed from FM coordinates (r = -0.017; p = 0.753, n = 337). The systematic error could be reduced by 43% to 5.6 o when the mean prostate position was estimated from 6 CT scans. Prostate rotation is a significant source of error that appears to be more accurately determined using the anatomical border of the prostate and rectum rather than FMs, thus highlighting the utility of CT image guidance.

Influence of Tool Rotational Speed and Post-Weld Heat Treatments on Friction Stir Welded Reduced Activation Ferritic-Martensitic Steel

Science.gov (United States)

Manugula, Vijaya L.; Rajulapati, Koteswararao V.; Reddy, G. Madhusudhan; Mythili, R.; Bhanu Sankara Rao, K.

2017-08-01

The effects of tool rotational speed (200 and 700 rpm) on evolving microstructure during friction stir welding (FSW) of a reduced activation ferritic-martensitic steel (RAFMS) in the stir zone (SZ), thermo-mechanically affected zone (TMAZ), and heat-affected zone (HAZ) have been explored in detail. The influence of post-weld direct tempering (PWDT: 1033 K (760 °C)/ 90 minutes + air cooling) and post-weld normalizing and tempering (PWNT: 1253 K (980 °C)/30 minutes + air cooling + tempering 1033 K (760 °C)/90 minutes + air cooling) treatments on microstructure and mechanical properties has also been assessed. The base metal (BM) microstructure was tempered martensite comprising Cr-rich M23C6 on prior austenite grain and lath boundaries with intra-lath precipitation of V- and Ta-rich MC precipitates. The tool rotational speed exerted profound influence on evolving microstructure in SZ, TMAZ, and HAZ in the as-welded and post-weld heat-treated states. Very high proportion of prior austenitic grains and martensite lath boundaries in SZ and TMAZ in the as-welded state showed lack of strengthening precipitates, though very high hardness was recorded in SZ irrespective of the tool speed. Very fine-needle-like Fe3C precipitates were found at both the rotational speeds in SZ. The Fe3C was dissolved and fresh precipitation of strengthening precipitates occurred on both prior austenite grain and sub-grain boundaries in SZ during PWNT and PWDT. The post-weld direct tempering caused coarsening and coalescence of strengthening precipitates, in both matrix and grain boundary regions of TMAZ and HAZ, which led to inhomogeneous distribution of hardness across the weld joint. The PWNT heat treatment has shown fresh precipitation of M23C6 on lath and grain boundaries and very fine V-rich MC precipitates in the intragranular regions, which is very much similar to that prevailed in BM prior to FSW. Both the PWDT and PWNT treatments caused considerable reduction in the hardness of SZ

Design of a rotating-hearth furnace

Energy Technology Data Exchange (ETDEWEB)

Behrens, H A [LOI Industrieofenanlagen G.m.b.H., Essen (Germany, F.R.)

1979-09-01

Part I of this paper is intended to present a review of the theory of heating round stock of a length considerably exceeding the diameter. It is permissible to neglect heating from the ends of the cylinders. With short and thick ingots as used in pilgrim mills, for instance, such simplification is not possible. The method for calculating the waste gas temperature can also be used for the remaining furnace sections provided certain conditions are allowed for and computational procedures observed. Part II of the paper will deal with this and with the major design features of rotating-hearth furnaces.

Isotopic separation by centrifugation. Rotating plasma

International Nuclear Information System (INIS)

Perello, M.; Vigon, M. A.

1972-01-01

The motion of a gas simultaneously submitted to an electric discharge and magnetic field has been studied in order to analyze the possibility of producing isotopes separation by rotation of a plasma. Some experimental results obtained under different discharge conditions are also given. Differences of pressure up to 15 mm oil between both electrodes has been attained. No definite conclusion on separation factors could be reached because of the low reproducibility of results, probably due to the short duration of the discharge with a new chamber designed to support stronger thermal shocks more reliable data can be expected. (Author) 16 refs

Impacts of Rotation Schemes on Ground-Dwelling Beneficial Arthropods.

Science.gov (United States)

Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

2016-10-01

Crop rotation alters agroecosystem diversity temporally, and increasing the number of crops in rotation schemes can increase crop yields and reduce reliance on pesticides. We hypothesized that increasing the number of crops in annual rotation schemes would positively affect ground-dwelling beneficial arthropod communities. During 2012 and 2013, pitfall traps were used to measure activity-density and diversity of ground-dwelling communities within three previously established, long-term crop rotation studies located in Wisconsin and Illinois. Rotation schemes sampled included continuous corn, a 2-yr annual rotation of corn and soybean, and a 3-yr annual rotation of corn, soybean, and wheat. Insects captured were identified to family, and non-insect arthropods were identified to class, order, or family, depending upon the taxa. Beneficial arthropods captured included natural enemies, granivores, and detritivores. The beneficial community from continuous corn plots was significantly more diverse compared with the community in the 2-yr rotation, whereas the community in the 3-yr rotation did not differ from either rotation scheme. The activity-density of the total community and any individual taxa did not differ among rotation schemes in either corn or soybean. Crop species within all three rotation schemes were annual crops, and are associated with agricultural practices that make infield habitat subject to anthropogenic disturbances and temporally unstable. Habitat instability and disturbance can limit the effectiveness and retention of beneficial arthropods, including natural enemies, granivores, and detritivores. Increasing non-crop and perennial species within landscapes in conjunction with more diverse rotation schemes may increase the effect of biological control of pests by natural enemies. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Randomised placebo-controlled trial of teduglutide in reducing parenteral nutrition and/or intravenous fluid requirements in patients with short bowel syndrome

DEFF Research Database (Denmark)

Jeppesen, P B; Gilroy, R; Pertkiewicz, M

2011-01-01

Teduglutide, a GLP-2 analogue, may restore intestinal structural and functional integrity by promoting repair and growth of the mucosa and reducing gastric emptying and secretion, thereby increasing fluid and nutrient absorption in patients with short bowel syndrome (SBS). This 24-week placebo-co......-controlled study evaluated the ability of teduglutide to reduce parenteral support in patients with SBS with intestinal failure....

Thromboelastography (TEG) or rotational thromboelastometry (ROTEM) to monitor haemostatic treatment in bleeding patients

DEFF Research Database (Denmark)

Wikkelsø, A.; Wetterslev, J.; Møller, A. M.

2017-01-01

of publication status, publication date, blinding status, outcomes published or language from date of inception to 5 January 2016 in six bibliographic databases. We included 17 trials (1493 participants), most involving cardiac surgery. Thromboelastography or rotational thromboelastometry seemed to reduce...... strategies guided by thromboelastography or rotational thromboelastometry may reduce the need for blood products in patients with bleeding, but the results are mainly based on trials of elective cardiac surgery involving cardiopulmonary bypass, with low-quality evidence.......Coagulopathy and severe bleeding are associated with high mortality. We evaluated haemostatic treatment guided by the functional viscoelastic haemostatic assays, thromboelastography or rotational thromboelastometry in bleeding patients. We searched for randomised, controlled trials irrespective...

Energy crops in rotation. A review

Energy Technology Data Exchange (ETDEWEB)

Zegada-Lizarazu, Walter; Monti, Andrea [Department of Agroenvironmental Science and Technology, University of Bologna, Viale G. Fanin, 44 - 40127, Bologna (Italy)

2011-01-15

The area under energy crops has increased tenfold over the last 10 years, and there is large consensus that the demand for energy crops will further increase rapidly to cover several millions of hectares in the near future. Information about rotational systems and effects of energy crops should be therefore given top priority. Literature is poor and fragmentary on this topic, especially about rotations in which all crops are exclusively dedicated to energy end uses. Well-planned crop rotations, as compared to continuous monoculture systems, can be expected to reduce the dependence on external inputs through promoting nutrient cycling efficiency, effective use of natural resources, especially water, maintenance of the long-term productivity of the land, control of diseases and pests, and consequently increasing crop yields and sustainability of production systems. The result of all these advantages is widely known as crop sequencing effect, which is due to the additional and positive consequences on soil physical-chemical and biological properties arising from specific crops grown in the same field year after year. In this context, the present review discusses the potential of several rotations with energy crops and their possibilities of being included alongside traditional agriculture systems across different agro-climatic zones within the European Union. Possible rotations dedicated exclusively to the production of biomass for bioenergy are also discussed, as rotations including only energy crops could become common around bio-refineries or power plants. Such rotations, however, show some limitations related to the control of diseases and to the narrow range of available species with high production potential that could be included in a rotation of such characteristics. The information on best-known energy crops such as rapeseed (Brassica napus) and sunflower (Helianthus annuus) suggests that conventional crops can benefit from the introduction of energy crops in

Turbulent convection in liquid metal with and without rotation

OpenAIRE

King, Eric M.; Aurnou, Jonathan M.

2013-01-01

The magnetic fields of Earth and other planets are generated by turbulent, rotating convection in liquid metal. Liquid metals are peculiar in that they diffuse heat more readily than momentum, quantified by their small Prandtl numbers, . Most analog models of planetary dynamos, however, use moderate fluids, and the systematic influence of reducing is not well understood. We perform rotating Rayleigh–Bénard convection experiments in the liquid metal gallium over a range of nondimensional bu...

Evolution of magnetized, differentially rotating neutron stars: Simulations in full general relativity

International Nuclear Information System (INIS)

Duez, Matthew D.; Liu, Yuk Tung; Shapiro, Stuart L.; Stephens, Branson C.; Shibata, Masaru

2006-01-01

We study the effects of magnetic fields on the evolution of differentially rotating neutron stars, which can be formed in stellar core collapse or binary neutron star coalescence. Magnetic braking and the magnetorotational instability (MRI) both act on differentially rotating stars to redistribute angular momentum. Simulations of these stars are carried out in axisymmetry using our recently developed codes which integrate the coupled Einstein-Maxwell-MHD equations. We consider stars with two different equations of state (EOS), a gamma-law EOS with Γ=2, and a more realistic hybrid EOS, and we evolve them adiabatically. Our simulations show that the fate of the star depends on its mass and spin. For initial data, we consider three categories of differentially rotating, equilibrium configurations, which we label normal, hypermassive and ultraspinning. Normal configurations have rest masses below the maximum achievable with uniform rotation, and angular momentum below the maximum for uniform rotation at the same rest mass. Hypermassive stars have rest masses exceeding the mass limit for uniform rotation. Ultraspinning stars are not hypermassive, but have angular momentum exceeding the maximum for uniform rotation at the same rest mass. We show that a normal star will evolve to a uniformly rotating equilibrium configuration. An ultraspinning star evolves to an equilibrium state consisting of a nearly uniformly rotating central core, surrounded by a differentially rotating torus with constant angular velocity along magnetic field lines, so that differential rotation ceases to wind the magnetic field. In addition, the final state is stable against the MRI, although it has differential rotation. For a hypermassive neutron star, the MHD-driven angular momentum transport leads to catastrophic collapse of the core. The resulting rotating black hole is surrounded by a hot, massive, magnetized torus undergoing quasistationary accretion, and a magnetic field collimated along

Effects of Tropical Rotation Crops on Meloidogyne arenaria Population Densities and Vegetable Yields in Microplots.

Science.gov (United States)

McSorley, R; Dickson, D W; de Brito, J A; Hewlett, T E; Frederick, J J

1994-06-01

The effects of 12 summer crop rotation treatments on population densities of Meloidogyne arenaria race 1 and on yields of subsequent spring vegetable crops were determined in microplots. The crop sequence was: (i) rotation crops during summer 1991 ; (ii) cover crop of rye (Secale cereale) during winter 1991-92; (iii) squash (Cucurbita pepo) during spring 1992; (iv) rotation crops during summer 1992; (v) rye during winter 1992-93; (vi) eggplant (Solanum melongena) during spring 1993. The 12 rotation treatments were castor (Ricinus communis), cotton (Gossypium hirsutum), velvetbean (Mucuna deeringiana), crotalaria (Crotalaria spectabilis), fallow, hairy indigo (Indigofera hirsuta), American jointvetch (Aeschynomene americana), sorghum-sudangrass (Sorghum bicolor x S. sudanense), soybean (Glycine max), horsebean (Canavalia ensiformis), sesame (Sesamum indicum), and peanut (Arachis hypogaea). Compared to peanut, the first eight rotation treatments resulted in lower (P crops may provide a means for depressing M. arenaria population densities on a short-term basis to enhance yields in a subsequent susceptible vegetable crop.

Theory of symmetry and of exact solution properties for fast rotating nuclei; Theorie de la symetrie et des proprietes de solutions exactes pour les noyaux en rotation rapide

Energy Technology Data Exchange (ETDEWEB)

Heydon, B

1995-07-19

We propose a study of rotating multi-fermionic systems. The method we developed is based on unitary group theory. The formalism of Gel`fand-Tsetlin is is simplified to binary calculations. With the help of operator of Casimir and physical interpretations using dichotomic symmetries (signature, parity), we show rotating Hamiltonians obey to a new quantum symmetry called P. The study of short range two-body interaction breaking weakly this symmetry, is made by using single j-shell. Nuclear interactions coupling two j-shell are introduced. This study allows us to compare ours results to experimental data for three isotopes of Zirconium. (author). 155 refs.

Fault Diagnosis for Rotating Machinery: A Method based on Image Processing.

Directory of Open Access Journals (Sweden)

Chen Lu

Full Text Available Rotating machinery is one of the most typical types of mechanical equipment and plays a significant role in industrial applications. Condition monitoring and fault diagnosis of rotating machinery has gained wide attention for its significance in preventing catastrophic accident and guaranteeing sufficient maintenance. With the development of science and technology, fault diagnosis methods based on multi-disciplines are becoming the focus in the field of fault diagnosis of rotating machinery. This paper presents a multi-discipline method based on image-processing for fault diagnosis of rotating machinery. Different from traditional analysis method in one-dimensional space, this study employs computing method in the field of image processing to realize automatic feature extraction and fault diagnosis in a two-dimensional space. The proposed method mainly includes the following steps. First, the vibration signal is transformed into a bi-spectrum contour map utilizing bi-spectrum technology, which provides a basis for the following image-based feature extraction. Then, an emerging approach in the field of image processing for feature extraction, speeded-up robust features, is employed to automatically exact fault features from the transformed bi-spectrum contour map and finally form a high-dimensional feature vector. To reduce the dimensionality of the feature vector, thus highlighting main fault features and reducing subsequent computing resources, t-Distributed Stochastic Neighbor Embedding is adopt to reduce the dimensionality of the feature vector. At last, probabilistic neural network is introduced for fault identification. Two typical rotating machinery, axial piston hydraulic pump and self-priming centrifugal pumps, are selected to demonstrate the effectiveness of the proposed method. Results show that the proposed method based on image-processing achieves a high accuracy, thus providing a highly effective means to fault diagnosis for

Fault Diagnosis for Rotating Machinery: A Method based on Image Processing.

Science.gov (United States)

Lu, Chen; Wang, Yang; Ragulskis, Minvydas; Cheng, Yujie

2016-01-01

Rotating machinery is one of the most typical types of mechanical equipment and plays a significant role in industrial applications. Condition monitoring and fault diagnosis of rotating machinery has gained wide attention for its significance in preventing catastrophic accident and guaranteeing sufficient maintenance. With the development of science and technology, fault diagnosis methods based on multi-disciplines are becoming the focus in the field of fault diagnosis of rotating machinery. This paper presents a multi-discipline method based on image-processing for fault diagnosis of rotating machinery. Different from traditional analysis method in one-dimensional space, this study employs computing method in the field of image processing to realize automatic feature extraction and fault diagnosis in a two-dimensional space. The proposed method mainly includes the following steps. First, the vibration signal is transformed into a bi-spectrum contour map utilizing bi-spectrum technology, which provides a basis for the following image-based feature extraction. Then, an emerging approach in the field of image processing for feature extraction, speeded-up robust features, is employed to automatically exact fault features from the transformed bi-spectrum contour map and finally form a high-dimensional feature vector. To reduce the dimensionality of the feature vector, thus highlighting main fault features and reducing subsequent computing resources, t-Distributed Stochastic Neighbor Embedding is adopt to reduce the dimensionality of the feature vector. At last, probabilistic neural network is introduced for fault identification. Two typical rotating machinery, axial piston hydraulic pump and self-priming centrifugal pumps, are selected to demonstrate the effectiveness of the proposed method. Results show that the proposed method based on image-processing achieves a high accuracy, thus providing a highly effective means to fault diagnosis for rotating machinery.

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

1999-01-01

In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belo...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion......In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

A case of iatrogenic stress? Results of the RCOG August rotation survey.

Science.gov (United States)

Cooke, M; Morris, E

2014-10-01

Although there are a number of studies of patient safety during the August rotation, they often focus on newly qualified doctors. It remains unclear whether negative impacts are due to doctors' inexperience, lack of technical skill or other aspects of rotation. This study used an electronic survey to seek the views of doctors working in obstetrics and gynaecology in the UK. A total of 1,879 responses were received. The August rotation was felt to be a stressful time, with a negative effect on patient care (82%) and safety (73%), lasting up to 1 month (62%). Although reducing services was thought to be helpful, there was strong support for staggering the rotation by grade (80%). This would ensure availability of doctors to cover services during the induction period, which should improve patient care and reduce staff stress. In addition, intensive skills training for junior staff and a supportive culture during the 1st month could optimise the integration and performance of doctors of all grades.

Interplay between intrinsic plasma rotation and magnetic island evolution in disruptive discharges

Energy Technology Data Exchange (ETDEWEB)

Ronchi, G.; Severo, J. H. F. [Universidade de São Paulo, Instituto de Física (Brazil); Salzedas, F. [Universidade do Porto, Faculdade de Engenharia (Portugal); Galvão, R. M. O., E-mail: rgalvao@if.usp.br; Sanada, E. K. [Universidade de São Paulo, Instituto de Física (Brazil)

2016-05-15

The behavior of the intrinsic toroidal rotation of the plasma column during the growth and eventual saturation of m/n = 2/1 magnetic islands, triggered by programmed density rise, has been carefully investigated in disruptive discharges in TCABR. The results show that, as the island starts to grow and rotate at a speed larger than that of the plasma column, the angular frequency of the intrinsic toroidal rotation increases and that of the island decreases, following the expectation of synchronization. As the island saturates at a large size, just before a major disruption, the angular speed of the intrinsic rotation decreases quite rapidly, even though the island keeps still rotating at a reduced speed. This decrease of the toroidal rotation is quite reproducible and can be considered as an indicative of disruption.

Space/age forestry: Implications of planting density and rotation age in SRIC management decisions

Energy Technology Data Exchange (ETDEWEB)

Merriam, R.A.; Phillips, V.D.; Liu, W.

1993-12-31

Short-rotation intensive-culture (SRIC) of promising tree crops is being evaluated worldwide for the production of methanol, ethanol, and electricity from renewable biomass resources. Planting density and rotation age are fundamental management decisions associated with SRIC energy plantations. Most studies of these variables have been conducted without the benefit of a unifying theory of the effects of growing space and rotation age on individual tree growth and stand level productivity. A modeling procedure based on field trials of Eucalyptus spp. is presented that evaluates the growth potential of a tree in the absence and presence of competition of neighboring trees in a stand. The results of this analysis are useful in clarifying economic implications of different growing space and rotation age decisions that tree plantation managers must make. The procedure is readily applicable to other species under consideration for SRIC plantations at any location.

Effects of root pruning on the growth and rhizosphere soil characteristics of short-rotation closed-canopy poplar

Energy Technology Data Exchange (ETDEWEB)

Du, Z. Y.; Xing, S. J.; Ma, B. Y.; Liu, F. C.; Ma, H. L.; Wang, Q. H.

2012-11-01

When poplar trees planted at a high density are canopy-closed in plantation after 4-5 years of growth, the roots of adjacent trees will inevitably intermingle together, which possibly restricts the nutrient uptake by root system. Root pruning might stimulate the emergence of fine roots and benefit the tree growth of short-rotation poplar at the stage of canopy closing. The aim of this study is to evaluate the effects of root pruning on DBH (diameter at breast height, 1.3 m), tree height, nutrients (N, P and K) and hormones (indoleacetic acid and cytokinin) in poplar leaves, gas exchange variables (photosynthetic rate and stomatal conductance), and rhizosphere soil characteristics. Field experiment was carried out with four-yearold poplar (Populus × euramericana cv. ‘Neva’) planted in a fluvo-aquic loam soil in Shandong province, China in early April, 2008. Three root pruning treatments (severe, moderate and light degree) were conducted at the distances of 6, 8 and 10 times DBH on both inter-row sides of the trees to the depth of 30 cm, respectively. The results showed that the growth performance was obtained in the following order of treatments: moderate > light = control > severe. In the rhizophere soil, moderate and light pruning increased the microbial populations, enzymatic activities, and the concentrations of available N, P, K and organic matter. Generally, root pruning to improve tree growth and rhizosphere soil fertility can be recommended in canopy-closed poplar plantation. The appropriate selection of root pruning intensity is a pivotal factor for the effectiveness of this technique. (Author) 35 refs.

A rotation/magnetism analogy for the quark–gluon plasma

Directory of Open Access Journals (Sweden)

Brett McInnes

2016-10-01

Full Text Available In peripheral heavy ion collisions, the Quark–Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.

The rotation measures of radio sources and their interpretation

International Nuclear Information System (INIS)

Vallee, J.P.; Kronberg, P.P.

1975-01-01

Rotation measures of 251 discrete radio sources have been determined after incorporating new polarization data at short wavelenghts. These have been applied to a 'slab' model-fitting technique to determine the most likely spiral arm magnetic field structure. The best agreement is obtained for a longitudinal spiral arm magnetic field, directed toward (lII approximately 90 0 , bII approximately 0 0 ), but perturbed by an anomaly towards the North Galactic Spur. (orig.) [de

VARIABILITY IN HOT CARBON-DOMINATED ATMOSPHERE (HOT DQ) WHITE DWARFS: RAPID ROTATION?

Energy Technology Data Exchange (ETDEWEB)

Williams, Kurtis A.; Bierwagen, Michael [Department of Physics and Astrophysics, Texas A and M University-Commerce, P.O. Box 3011, Commerce, TX, 75429 (United States); Montgomery, M. H.; Winget, D. E.; Falcon, Ross E., E-mail: Kurtis.Williams@tamuc.edu [Department of Astronomy, University of Texas, 1 University Station C1400, Austin, TX, 78712 (United States)

2016-01-20

Hot white dwarfs (WDs) with carbon-dominated atmospheres (hot DQs) are a cryptic class of WDs. In addition to their deficiency of hydrogen and helium, most of these stars are highly magnetic, and a large fraction vary in luminosity. This variability has been ascribed to nonradial pulsations, but increasing data call this explanation into question. We present studies of short-term variability in seven hot DQ WDs. Three (SDSS J1426+5752, SDSS J2200−0741, and SDSS J2348−0942) were known to be variable. Their photometric modulations are coherent over at least two years, and we find no evidence for variability at frequencies that are not harmonics. We present the first time-series photometry for three additional hot DQs (SDSS J0236−0734, SDSS J1402+3818, and SDSS J1615+4543); none are observed to vary, but the signal-to-noise is low. Finally, we present high speed photometry for SDSS J0005−1002, known to exhibit a 2.1-day photometric variation; we do not observe any short-term variability. Monoperiodicity is rare among pulsating WDs, so we contemplate whether the photometric variability is due to rotation rather than pulsations; similar hypotheses have been raised by other researchers. If the variability is due to rotation, then hot DQ WDs as a class contain many rapid rotators. Given the lack of companions to these stars, the origin of any fast rotation is unclear—both massive progenitor stars and double degenerate merger remnants are possibilities. We end with suggestions of future work that would best clarify the nature of these rare, intriguing objects.

A short-term, comprehensive, yoga-based lifestyle intervention is efficacious in reducing anxiety, improving subjective well-being and personality

Directory of Open Access Journals (Sweden)

Raj Kumar Yadav

2012-01-01

Full Text Available Objective: To assess the efficacy of a short-term comprehensive yoga-based lifestyle intervention in reducing anxiety, improving subjective well-being and personality. Materials and Methods: The study is a part of an ongoing larger study at a tertiary care hospital. Participants (n=90 included patients with chronic diseases attending a 10-day, yoga-based lifestyle intervention program for prevention and management of chronic diseases, and healthy controls (n=45 not attending any such intervention. Primary Outcome Measures: Change in state and trait anxiety questionnaire (STAI-Y; 40 items, subjective well-being inventory (SUBI; 40 items, and neuroticism extraversion openness to experience five factor personality inventory revised (NEO-FF PI-R; 60 items at the end of intervention. Results: Following intervention, the STAI-Y scores reduced significantly (P0.01 at Day 10 versus Day 1. Similarly NEO-FF PI-R scores improved significantly (P<0.001 at Day 10 versus Day 1. Control group showed an increase in STAI-Y while SUBI and NEO-FF PI-R scores remained comparable at Day 10 versus Day 1. Conclusions: The observations suggest that a short-term, yoga-based lifestyle intervention may significantly reduce anxiety and improve subjective well-being and personality in patients with chronic diseases.

Anticrab cavities for the removal of spurious vertical bunch rotations caused by crab cavities

Directory of Open Access Journals (Sweden)

G. Burt

2008-09-01

Full Text Available Many particle accelerators are proposing the use of crab cavities to correct for accelerator crossing angles or for the production of short bunches in light sources. These cavities produce a rotation to the bunch in a well-defined polarization plane. If the plane of the rotation does not align with the horizontal axis of the accelerator, the bunch will receive a small amount of spurious vertical bunch rotation. For accelerators with small vertical beam sizes and large beam-beam effects, this can cause significant unwanted effects. In this paper we propose the use of a 2nd smaller crab cavity in the vertical plane in order to cancel this effect and investigate its use in numerical simulations.

Earth's Rotation: A Challenging Problem in Mathematics and Physics

Science.gov (United States)

Ferrándiz, José M.; Navarro, Juan F.; Escapa, Alberto; Getino, Juan

2015-01-01

A suitable knowledge of the orientation and motion of the Earth in space is a common need in various fields. That knowledge has been ever necessary to carry out astronomical observations, but with the advent of the space age, it became essential for making observations of satellites and predicting and determining their orbits, and for observing the Earth from space as well. Given the relevant role it plays in Space Geodesy, Earth rotation is considered as one of the three pillars of Geodesy, the other two being geometry and gravity. Besides, research on Earth rotation has fostered advances in many fields, such as Mathematics, Astronomy and Geophysics, for centuries. One remarkable feature of the problem is in the extreme requirements of accuracy that must be fulfilled in the near future, about a millimetre on the tangent plane to the planet surface, roughly speaking. That challenges all of the theories that have been devised and used to-date; the paper makes a short review of some of the most relevant methods, which can be envisaged as milestones in Earth rotation research, emphasizing the Hamiltonian approach developed by the authors. Some contemporary problems are presented, as well as the main lines of future research prospected by the International Astronomical Union/International Association of Geodesy Joint Working Group on Theory of Earth Rotation, created in 2013.

Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma

Energy Technology Data Exchange (ETDEWEB)

Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)

2013-07-01

The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.

Analytic vibration-rotational matrix elements for diatomic molecules

International Nuclear Information System (INIS)

Bouanich, J.P.

1987-01-01

The vibration-rotational matrix elements for infrared or Raman transitions vJ → v'J' of diatomic molecules are calculated for powers of the reduced displacement X from parameters of the Dunham potential-energy function. (orig.)

Chromospheric rotation. II. Dependence on the size of chromospheric features

Energy Technology Data Exchange (ETDEWEB)

Azzarelli, L; Casalini, P; Cerri, S; Denoth, F [Consiglio Nazionale delle Ricerche, Pisa (Italy). Ist. di Elaborazione della Informazione

1979-08-01

The dependence of solar rotation on the size of the chromospheric tracers is considered. On the basis of an analysis of Ca II K/sub 3/ daily filtergrams taken in the period 8 May-14 August, 1972, chromospheric features can be divided into two classes according to their size. Features with size falling into the range 24 000-110 000 km can be identified with network elements, while those falling into the range 120 000-300 000 km with active regions, or brightness features of comparable size present at high latitudes. The rotation rate is determined separately for the two families of chromospheric features by means of a cross-correlation technique directly yields the average daily displacement of tracers due to rotation. Before computing the cross-correlation functions, chromospheric brightness data have been filtered with appropriate bandpass and highpass filters for separating spatial periodicities whose wavelengths fall into the two ranges of size, characteristic of the network pattern and of the activity centers. A difference less than 1% of the rotation rate of the two families of chromospheric features has been found. This is an indication for a substantial corotation at chromospheric levels of different short-lived features, both related to solar activity and controlled by the convective supergranular motions.

Rotational Seismology Workshop of February 2006

Science.gov (United States)

Evans, John R.; Cochard, A.; Graizer, Vladimir; Huang, Bor-Shouh; Hudnut, Kenneth W.; Hutt, Charles R.; Igel, H.; Lee, William H.K.; Liu, Chun-Chi; Majewski, Eugeniusz; Nigbor, Robert; Safak, Erdal; Savage, William U.; Schreiber, U.; Teisseyre, Roman; Trifunac, Mihailo; Wassermann, J.; Wu, Chien-Fu

2007-01-01

seismology (Cochard, Igel, Schreiber, Teisseyre, Wassermann, Majewski), sensor-calibration issues (Evans, Hutt), and finally the summary and conclusions (Savage). As a direct result of the 2006 Workshop and the formation of IWGoRS, we held a special session at the Fall 2006 AGU meeting (convened by H. Igel, W.H.K. Lee, and M.I. Todorovska). Currently, the first formal Workshop of the IWGoRS is being organized by W.H.K. Lee, M. Celebi, and M. I. Todorovska with sponsorship by the USGS and assistance from many others; this First International Workshop on Rotational Seismology and Engineering Applications will be held in September 2007 at Menlo Park, California (http://pubs.usgs.gov/of/2007/1144/). The following summarizes presentations and discussions during and shortly after the informal Workshop of February 2006.

Poloidal plasma rotation in the presence of RF waves in tokamaks

International Nuclear Information System (INIS)

Weyssow, B.; Liu, Caigen

2001-01-01

It is well known that one of the consequences of strong RF heating is the deformation of the equilibrium distribution function that induces a change in plasma transport and plasma rotation. The poloidal plasma rotation during RF wave heating in tokamaks is investigated using a moment approach. A set of closed, self-consistent transport and rotation equations is derived and reduced to a single equation for the poloidal particle flux. The formulas are sufficiently general to apply to heating schemes that can be represented by a quasilinear operator. (author)

Asteroid rotation rates

International Nuclear Information System (INIS)

Binzel, R.P.; Farinella, P.

1989-01-01

Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

The effects of short-term overfeeding on insulin action in lean and reduced-obese individuals.

Science.gov (United States)

Cornier, Marc-Andre; Bergman, Bryan C; Bessesen, Daniel H

2006-09-01

Insulin resistance is clearly associated with obesity. However, the role of excess energy intake per se as opposed to increased fat mass in the development of insulin resistance has not been clearly defined. It may be that the nutrient load provided by short-term overfeeding is sufficient to induce measurable changes in insulin action in skeletal muscle and the liver. We examined the effects of 3 days of overfeeding on insulin action and glucose kinetics in 13 lean (body mass index, 20.9 +/- 2.4 kg/m(2); 6 men, 7 women) and 9 reduced-obese (RO) (body mass index, 29.1 +/- 2.2 kg/m(2); 4 men, 5 women) individuals. A two-step euglycemic hyperinsulinemic clamp study (5 and 40 mU m(-2) min(-1)) with a primed, constant infusion of [6,6-(2)H(2)]glucose was performed after 3 days of a weight-maintenance diet and again after 3 days of overfeeding by 50% (50% carbohydrate, 30% fat, 20% protein). At baseline, lean individuals were more insulin sensitive, as measured by glucose infusion rate, than RO individuals (12.08 +/- 0.8 vs 7.62 +/- 1.0 mg x kg(-1) x min(-1), P lean women being more insulin sensitive than lean men (P lean women (13.37 +/- 1.3 to 11.42 +/- 1.0 mg x kg(-1) x min(-1), P lean men or RO individuals. Basal and insulin-stimulated glucose disposal remained unchanged with overfeeding in all groups. Low-dose insulin suppression of endogenous glucose production was impaired after overfeeding in lean women (euenergetic, 1.92 +/- 0.36 to 0.36 +/- 0.16 mg x kg(-1) x min(-1); overfeeding: 2.13 +/- 0.17 to 0.86 +/- 0.12 mg x kg(-1) x min(-1); P = .04) but remained unchanged in the other groups. These findings demonstrate that insulin action is reduced in lean, obese-resistant women after short-term overfeeding primarily because of an inhibition of insulin-mediated suppression of endogenous glucose production, whereas short-term overfeeding does not appear to effect insulin action in lean men and RO individuals. This response may be indirectly involved in the ability of

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

2001-01-01

In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong ...... approximations to the Riemannian metric, and that the subsequent corrections are inherent in the least squares estimation.......In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Management with willow short rotation coppice increase the functional gene diversity and functional activity of a heavy metal polluted soil.

Science.gov (United States)

Xue, K; van Nostrand, J D; Vangronsveld, J; Witters, N; Janssen, J O; Kumpiene, J; Siebielec, G; Galazka, R; Giagnoni, L; Arenella, M; Zhou, J-Z; Renella, G

2015-11-01

We studied the microbial functional diversity, biochemical activity, heavy metals (HM) availability and soil toxicity of Cd, Pb and Zn contaminated soils, kept under grassland or short rotation coppice (SRC) to attenuate the risks associated with HM contamination and restore the soil ecological functions. Soil microbial functional diversity was analyzed by the GeoChip, a functional gene microarray containing probes for genes involved in nutrient cycling, metal resistance and stress response. Soil under SRC showed a higher abundance of microbial genes involved in C, N, P and S cycles and resistance to various HM, higher microbial biomass, respiration and enzyme activity rates, and lower HM availability than the grassland soil. The linkages between functional genes of soil microbial communities and soil chemical properties, HM availability and biochemical activity were also investigated. Soil toxicity and N, P and Pb availability were important factors in shaping the microbial functional diversity, as determined by CCA. We concluded that in HM contaminated soils the microbial functional diversity was positively influenced by SRC management through the reduction of HM availability and soil toxicity increase of nutrient cycling. The presented results can be important in predicting the long term environmental sustainability of plant-based soil remediation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Successful Expansion of an Underexpanded Stent by Rotational Atherectomy

Science.gov (United States)

Vales, Lori; Coppola, John; Kwan, Tak

2013-01-01

The current routine use of intracoronary stents in percutaneous coronary intervention (PCI) has significantly reduced rates of restenosis, compared with balloon angioplasty alone. On the contrary, small post-stenting luminal dimensions due to undilatable, heavily calcified plaques have repeatedly been shown to significantly increase the rates of in-stent restenosis. Rotational atherectomy of lesions is an alternative method to facilitate PCI and prevent underexpansion of stents, when balloon angioplasty fails to successfully dilate a lesion. Stentablation, using rotational atherectomy to expand underexpanded stents deployed in heavily calcified plaques, has also been reported. We report a case via the transradial approach of rotational-atherectomy–facilitated PCI of in-stent restenosis of a severely underexpanded stent due to a heavily calcified plaque. We review the literature and suggest rotational atherectomy may have a role in treating a refractory, severely underexpanded stent caused by a heavily calcified plaque through various proposed mechanisms. PMID:24436587

Rabi oscillations in the dissociative continuum: Rotation and alignment effects

Science.gov (United States)

Granucci, Giovanni; Magnier, Sylvie; Persico, Maurizio

2002-01-01

We have simulated a set of experiments in which Rabi oscillations are induced in bound-free and free-free transitions of a diatomic molecule. Dissociative vibrational states belonging to different electronic terms are involved. We show analytically and confirm computationally that a simple relationship exists between the one-dimensional dynamics of a molecule with fixed orientation with respect to the polarization of the radiation field and the three-dimensional dynamics of a rotating system. It is demonstrated that sufficiently short laser pulses can induce oscillations in the probabilities of two coupled electronic states, and in the yields of the respective dissociation products, as functions of the radiation intensity. As a result of molecular rotation the oscillations are damped but not washed out. The initial thermal distribution on several rotational levels has a negligible effect on the photodissociation yields and other experimentally relevant quantities. Since the molecule undergoes a strong alignment along the polarization axis of the laser field, the ejection of atoms and ions is anisotropic. We have chosen the well known diatomic ion Na2+ as a convenient example.

Is external rotation the correct immobilisation for acute shoulder dislocation? An MRI study.

Science.gov (United States)

Siegler, J; Proust, J; Marcheix, P S M; Charissoux, J L; Mabit, C; Arnaud, J P

2010-06-01

Anterior dislocation of the shoulder is frequent, with high rates of recurrence. Immobilization in external rotation (ER) seems to improve results, although few studies have actually demonstrated this. The present MRI study examined the impact of ER on labral and capsular ligamentous complex lesions after primary dislocation. A prospective study was started up on January 1st, 2007. Inclusion criteria were: acute initial anteromedial dislocation of the shoulder, without past history of shoulder trauma. There were 23 such patients, with a mean age of 37 years. Early MRI scan used the following protocol: one acquisition in internal rotation followed by one in ER. Study criteria were: hemarthrosis, ER amplitude, rotator cuff status, bone lesion, and labral lesion stage (Habermeyer's classification) and displacement (Itoi criteria). There were 12 right and 11 left shoulders. Mean time to MRI was 3.7 days. There were three rotator cuff tears, no glenal lesions, and 14 humeral notches. Hemarthrosis was almost systematically present, with its distribution modified by ER in 75% of cases; three patients showed no posterior hemarthrosis, in whatever rotation. Mean ER was 37 degrees. On Habermeyer's classification, there were 12 stage-1 lesions, and 10 stage-2; one patient had no labral lesion. All separated labra were reduced in ER, five (21%) totally. In six cases, labral displacement changed according to rotation. All anterior joint effusion was reduced in ER, in three cases totally. According to Itoi among others, immobilization in ER is the way to reduce recurrence of anterior dislocation. The present study confirmed that labral reduction was systematic with ER, but it was by no means always complete. ER seemed more effective in reducing the separation. Results further confirmed that ER reduced anterior capsule volume, a recurrence factor. ER reduced hemarthrosis, anterior capsule detachment and labral lesions, and never the contrary. The interest of immobilization in ER

Short rotation plantations policy history in Europe: lessons from the past and recommendations for the future.

Science.gov (United States)

Lindegaard, Kevin N; Adams, Paul W R; Holley, Martin; Lamley, Annette; Henriksson, Annika; Larsson, Stig; von Engelbrechten, Hans-Georg; Esteban Lopez, Gonzalo; Pisarek, Marcin

2016-08-01

Short rotation plantations (SRPs) are fast-growing trees (such as willow ( Salix spp.), poplar ( Populus spp.) and Eucalyptus ) grown closely together and harvested in periods of 2-20 years. There are around 50,000 hectares of SRPs in Europe, a relatively small area considering that there have been supportive policy measures in many countries for 30 years. This paper looks at the effect that the policy measures used in different EU countries have had, and how other external factors have impacted on the development of the industry. Rokwood was a 3-year European funded project which attempted to understand the obstacles and barriers facing the woody energy crops sector using well established methods of SWOT and PESTLE analysis. Stakeholder groups were formed in six different European regions to analyze the market drivers and barriers for SRP and propose ways that the industry could make progress through targeted research and development and an improved policy framework. Based upon the outcomes of the SWOT and PESTLE analysis, each region produced a series of recommendations for policymakers, public authorities, and government agencies to support the development, production, and use of SRP-derived wood fuel in each of the partner countries. This study provides details of the SRP policy analysis and reveals that each region shared a number of similarities with broad themes emerging. There is a need to educate farmers and policymakers about the multifunctional benefits of SRPs. Greater financial support from regional and/or national government is required in order to grow the SRP market. Introducing targeted subsidies as an incentive for growers could address lack of local supply chains. Long-term policy initiatives should be developed while increasing clarity within Government departments. Research funding should enable closer working between universities and industry with positive research findings developed into supportive policy measures.

Energy balance and evaporation of a short-rotation willow forest. Variation with season and stand development

Energy Technology Data Exchange (ETDEWEB)

Iritz, Z.

1996-10-01

Energy balance and evaporation of a short-rotation willow (Salix viminalis L.) forest was studied in relation to season and stand development. The developmental stage of the forest stand considerably influenced how the energy, received as net radiation, was partitioned between the connective fluxes and the storage components. The main part of the available energy was utilised for evaporation during most of the season. Only at the beginning of the season did the willow forest supply heat to the atmosphere. Later in the season, energy was taken from air and utilised for evaporation, which resulted in negative sensible heat fluxes. Soil heat storage was also a significant term in the energy balance and also strongly depended on canopy development. Changes in energy partitioning relative to leaf area indices indicated the existence of a threshold value for leaf area index of the developing canopy. The analysis suggested that the canopy of the willow forest could be considered as closed at a leaf area index of 2. It was further found that evaporation from well-irrigated willow forest occurred also during night-time, particularly in windy and dry weather conditions. The sources of nocturnal evaporation were both the canopy, i.e. indicating non-closed stomata, and the soil surface. Partitioning of the total evaporation into components was investigated using a physically-based model with a two-layer aboveground representation and a two-layer soil module. The model estimates evaporation with respect to developmental stage of the willow stand and also takes into account the interaction between the fluxes from the canopy and the soil surface. Good performance of the model indicated that, after further testing in drier conditions, it could be used as a tool for analysing the prerequisites for energy-forest establishment, and practical management of energy forest stands. 37 refs, 9 figs

Wave induced supersonic rotation in mirrors

Science.gov (United States)

Fetterman, Abraham

2010-11-01

Wave-particle interactions in ExB supersonically rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy [1]. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field [2]. In the rotating frame, this perturbation is seen as a wave near the alpha particle cyclotron harmonic, and can break the azimuthal symmetry and magnetic moment conservation without changing the particle's total energy. The particle may exit if it reduces its kinetic energy and becomes more trapped if it gains kinetic energy, leading to a steady state current that maintains the field. Simulations of single particles in rotating mirrors show that a stationary wave can extract enough energy from alpha particles for a reactor to be self-sustaining. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation [3]. [4pt] [1] A. J. Fetterman and N. J. Fisch, Phys Rev Lett 101, 205003 (2008). [0pt] [2] A. J. Fetterman and N. J. Fisch, Phys. Plasmas 17, 042112 (2010). [0pt] [3] A. J. Fetterman and N. J. Fisch, Plasma Sources Sci. Tech. 18, 045003 (2009).

VMAT optimization with dynamic collimator rotation.

Science.gov (United States)

Lyu, Qihui; O'Connor, Daniel; Ruan, Dan; Yu, Victoria; Nguyen, Dan; Sheng, Ke

2018-04-16

Although collimator rotation is an optimization variable that can be exploited for dosimetric advantages, existing Volumetric Modulated Arc Therapy (VMAT) optimization uses a fixed collimator angle in each arc and only rotates the collimator between arcs. In this study, we develop a novel integrated optimization method for VMAT, accounting for dynamic collimator angles during the arc motion. Direct Aperture Optimization (DAO) for Dynamic Collimator in VMAT (DC-VMAT) was achieved by adding to the existing dose fidelity objective an anisotropic total variation term for regulating the fluence smoothness, a binary variable for forming simple apertures, and a group sparsity term for controlling collimator rotation. The optimal collimator angle for each beam angle was selected using the Dijkstra's algorithm, where the node costs depend on the estimated fluence map at the current iteration and the edge costs account for the mechanical constraints of multi-leaf collimator (MLC). An alternating optimization strategy was implemented to solve the DAO and collimator angle selection (CAS). Feasibility of DC-VMAT using one full-arc with dynamic collimator rotation was tested on a phantom with two small spherical targets, a brain, a lung and a prostate cancer patient. The plan was compared against a static collimator VMAT (SC-VMAT) plan using three full arcs with 60 degrees of collimator angle separation in patient studies. With the same target coverage, DC-VMAT achieved 20.3% reduction of R50 in the phantom study, and reduced the average max and mean OAR dose by 4.49% and 2.53% of the prescription dose in patient studies, as compared with SC-VMAT. The collimator rotation co-ordinated with the gantry rotation in DC-VMAT plans for deliverability. There were 13 beam angles in the single-arc DC-VMAT plan in patient studies that requires slower gantry rotation to accommodate multiple collimator angles. The novel DC-VMAT approach utilizes the dynamic collimator rotation during arc

Prospects for arable farm uptake of Short Rotation Coppice willow and miscanthus in England.

Science.gov (United States)

Glithero, Neryssa J; Wilson, Paul; Ramsden, Stephen J

2013-07-01

Biomass will play a role in the UK meeting EU targets on renewable energy use. Short Rotation Coppice (SRC) and miscanthus are potential biomass feedstocks; however, supply will rely on farmer willingness to grow these crops. Despite attractive crop establishment grants for dedicated energy crops (DECs) in the UK, uptake remains low. Drawing on results from an on-farm survey with 244 English arable farmers, 81.6% (87.7%) of farmers would not consider growing miscanthus (SRC), while respectively, 17.2% (11.9%) would consider growing and 1.2% (0.4%) were currently growing these crops. Farmer age, location, land ownership, farm type, farm size and farmer education level were not significant factors in determining acceptance of DECs. The main reasons cited for not growing DECs were impacts on land quality, lack of appropriate machinery, commitment of land for a long period of time, time to financial return and profitability. Reasons cited for willingness to grow DECs included land quality, ease of crop management, commitment of land for a long period of time, and profitability. Farmers cited a range of 'moral' (e.g. should not be using land for energy crops when there is a shortage of food), land quality, knowledge, profit and current farming practice comments as reasons for not growing DECs, while those willing to grow DECs cited interest in renewable energy, willingness to consider new crops, and low labour needs as rationale for their interest. Farm business objectives indicated that maximising profit and quality of life were most frequently cited as very important objectives. Previous research in the UK indicates that farmers in arable areas are unlikely to convert large areas of land to DECs, even where these farmers have an interest and willingness to grow them. Assuming that those farmers interested in growing DECs converted 9.29% (average percentage of arable land set-aside between 1996 and 2005) of their utilised agricultural area to these crops, 50,700�

Dynamics of molecular rotors confined in two dimensions: transition from a 2D rotational glass to a 2D rotational fluid in a periodic mesoporous organosilica.

Science.gov (United States)

Vogelsberg, Cortnie S; Bracco, Silvia; Beretta, Mario; Comotti, Angiolina; Sozzani, Piero; Garcia-Garibay, Miguel A

2012-02-09

The motional behavior of p-phenylene-d(4) rotators confined within the 2D layers of a hierarchically ordered periodic mesoporous p-divinylbenzenesilica has been elucidated to evaluate the effects of reduced dimensionality on the engineered dynamics of artificial molecular machines. The hybrid mesoporous material, characterized by a honeycomb lattice structure, has arrays of alternating p-divinylbenzene rotors and siloxane layers forming the molecularly ordered walls of the mesoscopic channels. The p-divinylbenzene rotors are strongly anchored between two adjacent siloxane sheets, so that the p-phenylene rotators are unable to experience translational diffusion and are allowed to rotate about only one fixed axis. Variable-temperature (2)H NMR experiments revealed that the p-phenylene rotators undergo an exchange process between sites related by 180° and a non-Arrhenius temperature dependence of the dynamics, with reorientational rates ranging from 10(3) to 10(8) Hz between 215 to 305 K. The regime of motion changes rapidly at about 280 K indicating the occurrence of a dynamical transition. The transition was also recognized by a steep change in the heat capacity at constant pressure. As a result of the robust lamellar architecture comprising the pore walls, the orientational dynamic disorder related to the phase transition is only realized in two dimensions within the layers, that is in the plane perpendicular to the channel axis. Thus, the aligned rotors that form the organic layers exhibit unique anisotropic dynamical properties as a result of the architecture's reduced dimensionality. The dynamical disorder restricted to two dimensions constitutes a highly mobile fluidlike rotational phase at room temperature, which upon cooling undergoes a transition to a more rigid glasslike phase. Activation energies of 5.9 and 9.5 kcal/mol respectively have been measured for the two dynamical regimes of rotation. Collectively, our investigation has led to the discovery of an

ARBRE monitoring - ecology of short rotation coppice. Four year study involving wildlife monitoring of commercial SCR plantations planted on arable land and arable control plots

Energy Technology Data Exchange (ETDEWEB)

Cunningham, M.D.; Bishop, J.D.; McKay, H.V.; Sage, R.B.

2004-07-01

This report summarises the findings of the UK Department of Trade and Industry (DTI) funded project monitoring wildlife within and around a number of commercially managed Short Rotation Coppice (SRC) plantations aimed at using the information gathered to assess the ecological impact of SRC plantations on the wildlife in the area. The background to the study is traced, and details are given of the monitoring programme examining the distribution of flora and fauna within the plantations, and the monitoring of birds, plants, insects and butterflies. The greater diversity of wildlife and plants in the SRC plots, the higher densities of birds, and the increasing number of butterfly species are discussed along with the increased mean number of invertebrate orders with subsequent growth of willow coppices, and the habitats at the edges of the plots and at headlands designed for access to machinery within the plots.

Rotator cuff exercises

Science.gov (United States)

... 25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder MRI scan Shoulder pain Patient Instructions Rotator cuff - self-care Shoulder surgery - discharge Using your ...

Late dislocation of rotating platform in New Jersey Low-Contact Stress knee prosthesis.

Science.gov (United States)

Huang, Chun-Hsiung; Ma, Hon-Ming; Liau, Jiann-Jong; Ho, Fang-Yuan; Cheng, Cheng-Kung

2002-12-01

Five patients with late rotational dislocation of the rotating platform bearing in the New Jersey Low-Contact Stress total knee arthroplasty are reported. The prostheses had functioned well for 8 to 12 years before failure. Preoperative radiographs showed asymmetric femorotibial joint spaces. Entrapment of the dislocated bearing in three patients and spontaneous reduction of the dislocated bearing in another two patients were seen at revision. Femorotibial ligamentous instability was found after reduction. The retrieved polyethylene bearings showed advanced wear and cold flow deformities and the thickness was reduced. The revision arthroplasty was accomplished by replacement with a thicker bearing element. Progressive femorotibial ligament laxity and reduction of the thickness of polyethylene with wearing break down the originally well-balanced soft tissue tension of the knee. The rotational degree of the rotating platform bearing is unrestricted, which may result in late dislocation. Polyethylene wear is unavoidable in knee prostheses using metal contact with polyethylene even with a mobile-bearing design. Efforts to reduce polyethylene wear are mandatory.

Introduction of an enhanced recovery protocol to reduce short-term complications following radical cystectomy and intestinal urinary diversion with vescica ileale Padovana neobladder.

Science.gov (United States)

Cerruto, Maria Angela; De Marco, Vincenzo; D'Elia, Carolina; Bizzotto, Leonardo; Curti, Pierpaolo; Baldassarre, Roberto; Artibani, Walter

2014-01-01

To reduce short-term complications of radical cystectomy (RC) and intestinal urinary diversion with vescica ileale Padovana (VIP) neobladder, we described and assessed an enhanced recovery protocol (ERP) in a series of consecutive patients. An ERP was introduced focusing on reduced bowel preparation, standardized feeding and analgesic regimens. We analyzed the outcomes with all patients consecutively undergoing RC and VIP neobladder who met the following inclusion criteria: American Society of Anesthesiologists score Short Form criteria; absence of inflammatory bowel diseases. Thirty-one consecutive patients were recruited to undergo our ERP. Mean age of patients was 62.16 years. No patients died due to surgical complications. Nine of 31 patients experienced complications (29.03%), none requiring surgical intervention. According to Clavien grading, all complications were grade <2. The application of our ERP to our patients undergoing RC and VIP neobladder contributed to reduce postoperative morbidity. Copyright © 2013 S. Karger AG, Basel.

Usage of stereoscopic visualization in the learning contents of rotational motion.

Science.gov (United States)

Matsuura, Shu

2013-01-01

Rotational motion plays an essential role in physics even at an introductory level. In addition, the stereoscopic display of three-dimensional graphics includes is advantageous for the presentation of rotational motions, particularly for depth recognition. However, the immersive visualization of rotational motion has been known to lead to dizziness and even nausea for some viewers. Therefore, the purpose of this study is to examine the onset of nausea and visual fatigue when learning rotational motion through the use of a stereoscopic display. The findings show that an instruction method with intermittent exposure of the stereoscopic display and a simplification of its visual components reduced the onset of nausea and visual fatigue for the viewers, which maintained the overall effect of instantaneous spatial recognition.

The range and effectiveness of short-term measures to reduce traffic emissions during high air pollution episodes

International Nuclear Information System (INIS)

Elsom, Derek M.

1999-01-01

Concern for continuing poor urban air quality, caused primarily by motor vehicles emissions, and the slow progress being made towards reducing total vehicle emissions by long-term measures, such as improving fuel and vehicle technologies, has prompted some authorities to try to reduce the severity and duration of high air pollution episodes by implementing short-term traffic restraint measures. This paper reviews the range of episodic air quality management schemes applied in cities around the world and comments on the effectiveness of such schemes. The difficulty of targeting vehicles according to the contribution they make to the air quality problem is highlighted. The problem of some schemes simply causing a displacement of the area of excessive vehicle emissions rather than reducing total emissions is reviewed. Rapid developments in telematics and improved urban air quality and traffic monitoring networks (e.g. Urban Traffic Management and Control systems) may offer significant improvements in the effectiveness of episodic management schemes in the future. (Author)

Short-term variability of binary and non-binary Trans-Neptunian Objects

Science.gov (United States)

Thirouin, Audrey; Noll, K. S.; Campo Bagatin, A.; Ortiz Moreno, J. L.; Morales, N.

2013-10-01

Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to understand such objects is to study their rotations by monitoring their brightness variations. By studying the rotational properties of the TNOs a wealth of information can be obtained on their physics. So, the study of the spins and shapes of TNOs is a powerful method of gaining information on the formation and evolution of our Solar System. We have observed most of the brightest TNOs and centaurs, and compiled one of the largest lightcurves samples. The main purpose was to increase the number of objects whose short-term variability has been studied and present a homogeneous dataset trying to avoid observational biases. A dataset composed of 54 TNOs/Centaurs is reported and analyzed. Amplitudes and rotational periods have been derived for 45 of them with different degrees of reliability. For 9 objects, only an estimation of the amplitude is reported. Because most of the TNOs/Centaurs have low amplitude lightcurves, it is difficult to distinguish between single- and double-peaked lightcurves. Based on our results and the literature, following Binzel et al. (1989) study about asteroids rotational frequency distribution, we studied the TNOs spin rate distributions. We performed several Maxwellian fits to various histograms obtained considering that the lightcurves are single- or double-peaked. We tested lightcurve amplitude limits to distinguish if the lightcurve is albedo- or shape-dominated. Such a consideration introduces important changes in the distribution. We derived that an amplitude limit of 0.15mag gave a good fit to Maxwellian distribution. So, it seems that 0.15mag is a good measure of the typical variability caused by albedo. We studied the short-term variability of binary TNOs thanks to unresolved lightcurves. Based on our results and those from the literature, we come up with a sample of 32 systems with a rotational period and/or lightcurve amplitude value

The new INRIM rotating encoder angle comparator (REAC)

International Nuclear Information System (INIS)

Pisani, Marco; Astrua, Milena

2017-01-01

A novel angle comparator has been built and tested at INRIM. The device is based on a double air bearing structure embedding a continuously rotating encoder, which is read by two heads: one fixed to the base of the comparator and a second fixed to the upper moving part of the comparator. The phase measurement between the two heads’ signals is proportional to the relative angle suspended between them (and, therefore, the angle between the base and the upper, movable part of the comparator). The advantage of this solution is to reduce the encoder graduation errors and to cancel the cyclic errors due to the interpolation of the encoder lines. By using only two pairs of reading heads, we have achieved an intrinsic accuracy of  ±0.04″ (rectangular distribution) that can be reduced through self-calibration. The residual cyclic errors have shown to be less than 0.01″ peak-to-peak. The random fluctuations are less than 0.01″ rms on a 100 s time interval. A further advantage of the rotating encoder is the intrinsic knowledge of the absolute position without the need of a zeroing procedure. Construction details of the rotating encoder angle comparator (REAC), characterization tests, and examples of practical use are given. (paper)

Nonlinearity in the rotational dynamics of Haidinger's brushes

Science.gov (United States)

Rothmayer, Mark; Dultz, Wolfgang; Frins, Erna; Zhan, Qiwen; Tierney, Dennis; Schmitzer, Heidrun

2007-10-01

Haidinger's brushes are an entoptic effect of the human visual system that enables us to detect polarized light. However, individual perceptions of Haidinger's brushes can vary significantly. We find that the birefringence of the cornea influences the rotational motion and the contrast of Haidinger's brushes and may offer an explanation for individual differences. We have devised an experimental setup to simulate various phase shifts of the cornea and found a switching effect in the rotational dynamics of Haidinger's brushes. In addition, age related macular degeneration reduces the polarization effect of the macula and thus also leads to changes in the brush pattern.

Surgery or conservative treatment for rotator cuff tear: a meta-analysis.

Science.gov (United States)

Ryösä, Anssi; Laimi, Katri; Äärimaa, Ville; Lehtimäki, Kaisa; Kukkonen, Juha; Saltychev, Mikhail

2017-07-01

Comparative evidence on treating rotator cuff tear is inconclusive. The objective of this review was to evaluate the evidence on effectiveness of tendon repair in reducing pain and improving function of the shoulder when compared with conservative treatment of symptomatic rotator cuff tear. Search on CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science and Pedro databases. Randomised controlled trials (RCT) comparing surgery and conservative treatment of rotator cuff tear. Study selection and extraction based on the Cochrane Handbook for Systematic reviews of Interventions. Random effects meta-analysis. Three identified RCTs involved 252 participants (123 cases and 129 controls). The risk of bias was considered low for all three RCTs. For Constant score, statistically insignificant effect size was 5.6 (95% CI -0.41 to 11.62) points in 1-year follow up favouring surgery and below the level of minimal clinically important difference. The respective difference in pain reduction was -0.93 (95% CI -1.65 to -0.21) cm on a 0-10 pain visual analogue scale favouring surgery. The difference was statistically significant (p = 0.012) in 1-year follow up but below the level of minimal clinically important difference. There is limited evidence that surgery is not more effective in treating rotator cuff tear than conservative treatment alone. Thus, a conservative approach is advocated as the initial treatment modality. Implications for Rehabilitation There is limited evidence that surgery is not more effective in treating rotator cuff tear than conservative treatment alone. There was no clinically significant difference between surgery and active physiotherapy in 1-year follow-up in improving Constant score or reducing pain caused by rotator cuff tear. As physiotherapy is less proneness to complications and less expensive than surgery, a conservative approach is advocated as the initial treatment modality to rotator cuff tears.

Combined CT-based and image-free navigation systems in TKA reduces postoperative outliers of rotational alignment of the tibial component.

Science.gov (United States)

Mitsuhashi, Shota; Akamatsu, Yasushi; Kobayashi, Hideo; Kusayama, Yoshihiro; Kumagai, Ken; Saito, Tomoyuki

2018-02-01

Rotational malpositioning of the tibial component can lead to poor functional outcome in TKA. Although various surgical techniques have been proposed, precise rotational placement of the tibial component was difficult to accomplish even with the use of a navigation system. The purpose of this study is to assess whether combined CT-based and image-free navigation systems replicate accurately the rotational alignment of tibial component that was preoperatively planned on CT, compared with the conventional method. We compared the number of outliers for rotational alignment of the tibial component using combined CT-based and image-free navigation systems (navigated group) with those of conventional method (conventional group). Seventy-two TKAs were performed between May 2012 and December 2014. In the navigated group, the anteroposterior axis was prepared using CT-based navigation system and the tibial component was positioned under control of the navigation. In the conventional group, the tibial component was placed with reference to the Akagi line that was determined visually. Fisher's exact probability test was performed to evaluate the results. There was a significant difference between the two groups with regard to the number of outliers: 3 outliers in the navigated group compared with 12 outliers in the conventional group (P image-free navigation systems decreased the number of rotational outliers of tibial component, and was helpful for the replication of the accurate rotational alignment of the tibial component that was preoperatively planned.

Outcome of Large to Massive Rotator Cuff Tears Repaired With and Without Extracellular Matrix Augmentation: A Prospective Comparative Study.

Science.gov (United States)

Gilot, Gregory J; Alvarez-Pinzon, Andres M; Barcksdale, Leticia; Westerdahl, David; Krill, Michael; Peck, Evan

2015-08-01

To compare the results of arthroscopic repair of large to massive rotator cuff tears (RCTs) with or without augmentation using an extracellular matrix (ECM) graft and to present ECM graft augmentation as a valuable surgical alternative used for biomechanical reinforcement in any RCT repair. We performed a prospective, blinded, single-center, comparative study of patients who underwent arthroscopic repair of a large to massive RCT with or without augmentation with ECM graft. The primary outcome was assessed by the presence or absence of a retear of the previously repaired rotator cuff, as noted on ultrasound examination. The secondary outcomes were patient satisfaction evaluated preoperatively and postoperatively using the 12-item Short Form Health Survey, the American Shoulder and Elbow Surgeons shoulder outcome score, a visual analog scale score, the Western Ontario Rotator Cuff index, and a shoulder activity level survey. We enrolled 35 patients in the study: 20 in the ECM-augmented rotator cuff repair group and 15 in the control group. The follow-up period ranged from 22 to 26 months, with a mean of 24.9 months. There was a significant difference between the groups in terms of the incidence of retears: 26% (4 retears) in the control group and 10% (2 retears) in the ECM graft group (P = .0483). The mean pain level decreased from 6.9 to 4.1 in the control group and from 6.8 to 0.9 in the ECM graft group (P = .024). The American Shoulder and Elbow Surgeons score improved from 62.1 to 72.6 points in the control group and from 63.8 to 88.9 points (P = .02) in the treatment group. The mean Short Form 12 scores improved in the 2 groups, with a statistically significant difference favoring graft augmentation (P = .031), and correspondingly, the Western Ontario Rotator Cuff index scores improved in both arms, favoring the treatment group (P = .0412). The use of ECM for augmentation of arthroscopic repairs of large to massive RCTs reduces the incidence of retears

Spin current pumped by a rotating magnetic field in zigzag graphene nanoribbons

International Nuclear Information System (INIS)

Wang, J; Chan, K S

2010-01-01

We study electron spin resonance in zigzag graphene nanoribbons by applying a rotating magnetic field on the system without any bias. By using the nonequilibrium Green's function technique, the spin-resolved pumped current is explicitly derived in a rotating reference frame. The pumped spin current density increases with the system size and the intensity of the transverse rotating magnetic field. For graphene nanoribbons with an even number of zigzag chains, there is a nonzero pumped charge current in addition to the pumped spin current owing to the broken spatial inversion symmetry of the system, but its magnitude is much smaller than the spin current. The short-ranged static disorder from either impurities or defects in the ribbon can depress the spin current greatly due to the localization effect, whereas the long-ranged disorder from charge impurities can avoid inter-valley scattering so that the spin current can survive in the strong disorder for the single-energy mode.

The interference effects of non-rotated versus counter-rotated trials in visuomotor adaptation.

Science.gov (United States)

Hinder, Mark R; Walk, Laura; Woolley, Daniel G; Riek, Stephan; Carson, Richard G

2007-07-01

An isometric torque-production task was used to investigate interference and retention in adaptation to multiple visuomotor environments. Subjects produced isometric flexion-extension and pronation-supination elbow torques to move a cursor to acquire targets as quickly as possible. Adaptation to a 30 degrees counter-clockwise (CCW) rotation (task A), was followed by a period of rest (control), trials with no rotation (task B0), or trials with a 60 degrees clockwise (CW) rotation (task B60). For all groups, retention of task A was assessed 5 h later. With initial training, all groups reduced the angular deviation of cursor paths early in the movements, indicating feedforward adaptation. For the control group, performance at commencement of the retest was significantly better than that at the beginning of the initial learning. For the B0 group, performance in the retest of task A was not dissimilar to that at the start of the initial learning, while for the B60 group retest performance in task A was markedly worse than initially observed. Our results indicate that close juxtaposition of two visuomotor environments precludes improved retest performance in the initial environment. Data for the B60 group, specifically larger angular errors upon retest compared with initial exposures, are consistent with the presence of anterograde interference. Furthermore, full interference occurred even when the visuomotor environment encountered in the second task was not rotated (B0). This latter novel result differs from those obtained for force field learning, where interference does not occur when task B does not impose perturbing forces, i.e., when B consists of a null field (Brashers-Krug et al., Nature 382:252-255, 1996). The results are consistent with recent proposals suggesting different interference mechanisms for visuomotor (kinematic) compared to force field (dynamic) adaptations, and have implications for the use of washout trials when studying interference between

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1976-01-01

Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

Earth rotation excitation mechanisms derived from geodetic space observations

Science.gov (United States)

Göttl, F.; Schmidt, M.

2009-04-01

Earth rotation variations are caused by mass displacements and motions in the subsystems of the Earth. Via the satellite Gravity and Climate Experiment (GRACE) gravity field variations can be identified which are caused by mass redistribution in the Earth system. Therefore time variable gravity field models (GFZ RL04, CSR RL04, JPL RL04, ITG-Grace03, GRGS, ...) can be used to derive different impacts on Earth rotation. Furthermore satellite altimetry provides accurate information on sea level anomalies (AVISO, DGFI) which are caused by mass and volume changes of seawater. Since Earth rotation is solely affected by mass variations and motions the volume (steric) effect has to be reduced from the altimetric observations in order to infer oceanic contributions to Earth rotation variations. Therefore the steric effect is estimated from physical ocean parameters such as temperature and salinity changes in the oceans (WOA05, Ishii). In this study specific individual geophysical contributions to Earth rotation variations are identified by means of a multitude of accurate geodetic space observations in combination with a realistic error propagation. It will be shown that due to adjustment of altimetric and/or gravimetric solutions the results for polar motion excitations can be improved.

ROTATION STATE OF COMET 103P/HARTLEY 2 FROM RADIO SPECTROSCOPY AT 1 mm

International Nuclear Information System (INIS)

Drahus, Michal; Jewitt, David; Guilbert-Lepoutre, Aurelie; Waniak, Waclaw; Hoge, James; Lis, Dariusz C.; Yoshida, Hiroshige; Peng, Ruisheng; Sievers, Albrecht

2011-01-01

The nuclei of active comets emit molecules anisotropically from discrete vents. As the nucleus rotates, we expect to observe periodic variability in the molecular emission line profiles, which can be studied through millimeter/submillimeter spectroscopy. Using this technique we investigated the HCN atmosphere of comet 103P/Hartley 2, the target of NASA's EPOXI mission, which had an exceptionally favorable apparition in late 2010. We detected short-term evolution of the spectral line profile, which was stimulated by the nucleus rotation, and which provides evidence for rapid deceleration and excitation of the rotation state. The measured rate of change in the rotation period is +1.00 ± 0.15 minutes day -1 and the period itself is 18.32 ± 0.03 hr, both applicable at the epoch of the EPOXI encounter. Surprisingly, the spin-down efficiency is lower by two orders of magnitude than the measurement in comet 9P/Tempel 1 and the best theoretical prediction. This secures rotational stability of the comet's nucleus during the next few returns, although we anticipate a catastrophic disruption from spin-up as its ultimate fate.

Maintaining yields and reducing nitrogen loss in rice–wheat rotation system in Taihu Lake region with proper fertilizer management

International Nuclear Information System (INIS)

Xue, Lihong; Yu, Yingliang; Yang, Linzhang

2014-01-01

In the Tailake region of China, heavy nitrogen (N) loss of rice–wheat rotation systems, due to high fertilizer-N input with low N use efficiency (NUE), was widely reported. To alleviate the detrimental impacts caused by N loss, it is necessary to improve the fertilizer management practices. Therefore, a 3 yr field experiments with different N managements including organic combined chemical N treatment (OCN, 390 kg N ha −1 yr −1 , 20% organic fertilizer), control–released urea treatment (CRU, 390 kg N ha −1 yr −1 , 70% resin-coated urea), reduced chemical N treatment (RCN, 390 kg N ha −1 yr −1 , all common chemical fertilizer), and site-specific N management (SSNM, 333 kg N ha −1 yr −1 , all common chemical fertilizer) were conducted in the Taihu Lake region with the ‘farmer’s N’ treatment (FN, 510 kg N ha −1 yr −1 , all common chemical fertilizer) as a control. Grain yield, plant N uptake (PNU), NUE, and N losses via runoff, leaching, and ammonia volatilization were assessed. In the rice season, the FN treatment had the highest N loss and lowest NUE, which can be attributed to an excessive rate of N application. Treatments of OCN and RCN with a 22% reduced N rate from FN had no significant effect on PNU nor the yield of rice in the 3 yr; however, the NUE was improved and N loss was reduced 20–32%. OCN treatment achieved the highest yield, while SSNM has the lowest N loss and highest NUE due to the lowest N rate. In wheat season, N loss decreased about 28–48% with the continuous reduction of N input, but the yield also declined, with the exception of OCN treatment. N loss through runoff, leaching and ammonia volatilization was positively correlated with the N input rate. When compared with the pure chemical fertilizer treatment of RCN under the same N input, OCN treatment has better NUE, better yield, and lower N loss. 70% of the urea replaced with resin-coated urea had no significant effect on yield and NUE improvement, but

EXAFS, Determination of Short Range Order and Local Structures in Materials

NARCIS (Netherlands)

Koningsberger, D.C.; Prins, R.

1981-01-01

Extended X-ray Absorption Fine Structure (EXAFS) is a powerful method of determining short range order and local structures in materials using X-ray photons produced by a synchrotron light source, or in-house by a high intensity rotating anode X-ray generator. The technique has provided valuable

Tendon patch grafting using the long head of the biceps for irreparable massive rotator cuff tears

International Nuclear Information System (INIS)

Sano, Hirotaka; Itoi, Eiji; Mineta, Mitsuyoshi; Kita, Atsushi

2010-01-01

Surgical treatment of massive rotator cuff tears is challenging for shoulder surgeons. The purpose of this study was to investigate both clinical outcomes and cuff integrity after tendon patch grafting using the long head of the biceps (LHB) tendon for irreparable massive rotator cuff tears. A short deltoid splitting approach was used to expose the torn cuff tendon stump. After tenodesis of the LHB tendon, its intraarticular portion was resected. If the size of the harvested tendon was smaller than that of the cuff defect, it was split into two layers. Then, the LHB tendon was sutured to the remnant cuff tendons and fixed to the footprint using the transosseous suture technique. A total of 14 patients (12 men, 2 women; average age 64 years) underwent this procedure. The average postoperative follow-up period was 28 months (range 12-51 months). Active elevation angle of the shoulder as well as the Japanese Orthopaedic Association (JOA) score were assessed before surgery and at the time of follow-up. Postoperative cuff integrity was assessed using T2-weighted magnetic resonance imaging (MRI). All cuff defects were successfully closed with this technique. Average active elevation angle improved from 69deg to 149deg. Total JOA score also improved from 54.7 points to 83.1 points. Thirteen shoulders showed no re-tearing on T2-weighted MRI; a minor discontinuity of the repaired cuff tendon was observed in the other shoulder. The LHB tendon is available in case tenodesis or tenotomy is needed. The resected tendon may be used as a graft for rotator cuff repair without any additional skin incision, which could reduce both the surgical invasion and the risk of infection. The LHB tendon patch grafting may be one of the useful options for surgical treatment of irreparable massive rotator cuff tears. (author)

Effect of length of dental resident clinical rotations on patient behavior.

Science.gov (United States)

Lau, Agnes

2018-01-01

The purpose of this retrospective chart review study was to determine if the length of residents' comprehensive dental care rotations in a general practice residency affected late cancellations, broken appointments, completion of treatment, timeliness of recall visits, emergency visits, and the need for redo of restorations and prostheses. Patients who presented for comprehensive care from 2010 to 2013, during which residents had 3- to 4-month dental clinic rotations, comprised Group 1, and patients who presented for comprehensive care from 2013 to 2016, during which residents had 11-month dental clinic rotations, comprised Group 2. Subjects were excluded if they only presented for emergency care, they had only one visit, or their care was delivered in both time periods. There were 105 patients in Group 1 and 55 patients in Group 2. The statistically significant results were that Group 1 patients had more late cancellations and broken appointments and failed to reach recall status more often than Group 2 patients, and that Group 1 patients had fewer emergency visits. Within the limitations of this retrospective study, the results suggest that short block rotations have an adverse effect on resident experience and outcomes of patient care in a hospital outpatient setting. © 2018 Special Care Dentistry Association and Wiley Periodicals, Inc.

Superconducting magnets for induction linac phase-rotation in a neutrino factory

International Nuclear Information System (INIS)

Green, M.A.; Yu, S.

2001-01-01

The neutrino factory[1-3] consists of a target section where pions are produced and captured in a solenoidal magnetic field. Pions in a range of energies from 100 Mev to 400 MeV decay into muons in an 18-meter long channel of 1.25 T superconducting solenoids. The warm bore diameter of these solenoids is about 600 mm. The phase rotation section slows down the high-energy muon and speeds up the low energy muons to an average momentum of 200 MeV/c. The phase-rotation channel consists of three induction linac channels with a short cooling section and a magnetic flux reversal section between the first and second induction linacs and a drift space between the second and third induction linacs. The length of the phase rotation channel will be about 320 meters. The superconducting coils in the channel are 0.36 m long with a gap of 0.14 m between the coils. The magnetic induction within the channel will be 1.25. For 260 meters of the 320-meter long channel, the solenoids are inside the induction linac. This paper discusses the design parameters for the superconducting solenoids in the neutrino factory phase-rotation channel

Transitions in rapidly rotating convection dynamos

Science.gov (United States)

Tilgner, A.

2013-12-01

It is commonly assumed that buoyancy in the fluid core powers the geodynamo. We study here the minimal model of a convection driven dynamo, which is a horizontal plane layer in a gravity field, filled with electrically conducting fluid, heated from below and cooled from above, and rotating about a vertical axis. Such a plane layer may be viewed as a local approximation to the geophysically more relevant spherical geometry. The numerical simulations have been run on graphics processing units with at least 960 cores. If the convection is driven stronger and stronger at fixed rotation rate, the flow behaves at some point as if it was not rotating. This transition shows in the scaling of the heat transport which can be used to distinguish slow from rapid rotation. One expects dynamos to behave differently in these two flow regimes. But even within the convection flows which are rapidly rotating according to this criterion, it will be shown that different types of dynamos exist. In one state, the magnetic field strength obeys a scaling indicative of a magnetostrophic balance, in which the Lorentz force is in equilibrium with the Coriolis force. The flow in this case is helical. A different state exists at higher magnetic Reynolds numbers, in which the magnetic energy obeys a different scaling law and the helicity of the flow is much reduced. As one increases the Rayleigh number, all other parameters kept constant, one may find both types of dynamos separated by an interval of Rayleigh numbers in which there are no dynamos at all. The effect of these transitions on energy dissipation and mean field generation have also been studied.

Rotational and translational diffusions of fluorescent probes during gelation process

Science.gov (United States)

Hattori, Yusuke; Panizza, Pascal; Letamendia, Louis; Ushiki, Hideharu

2006-04-01

Gelation process has been investigated by using light scattering techniques in recent years. We measured both of rotational and translational motions of fluorescent probes during gelation process. The measurements were performed after the temperature quenched at 30 °C. As the results, rotational diffusion coefficient of fluorescein was decreased after 6.0 × 10 4 s and energy transfer rate was reduced after 2.0 × 10 4 s. We sorted the gelation process into the following three parts, (I) pre-gelation, (II) reduction of translational diffusion (aging), and (III) reduction of rotational diffusion with saturating translational diffusion (post-gelation). The time scale of the process was completely different from the results of other methods.

Rotating NSs/QSs and recent astrophysical observations

International Nuclear Information System (INIS)

Li, Ang; Dong, Jianmin

2017-01-01

Both fast and slow configurations of rotating neutron stars (NSs) are studied with the recently-constructed unified NS EoSs. The calculations for pure quark stars (QSs) and hybrid stars (HSs) are also done, using several updated quark matter EoSs and Gibbs construction for obtaining hadron-quark mixed phase. All three types of EoSs fulfill the recent 2-solar-mass constraint. By confronting the glitch observations with the theoretical calculations for the crustal moment of inertia (MoI), we find that the glitch crisis is still present in Vela-like pulsars. An upcoming accurate MoI measurement (eg., a possible 10% accuracy for pulsar PSR J0737–3039A) allows one to distinguish QSs from NSs, since the MoIs of QSs are generally ≳ 1.5 times larger than NSs and HSs, no matter the compactness and the mass of the stars. Using tabulated EoSs, we compute stationary and equilibrium sequences of rapidly rotating, relativistic stars in general relativity from the well-tested rns code, assuming the matter comprising the star to be a perfect fluid. All three observed properties of the short gamma-ray bursts (SGRBs) internal plateaus sample are simulated using the rotating configurations of NSs/QSs as basic inputs. We finally argue that for some characteristic SGRBs, the post-merger products of NS-NS mergers are probably supramassive QSs rather than NSs, and NS-NS mergers are a plausible location for quark deconfinement and the formation of QSs. (paper)

Surface dimpling on rotating work piece using rotation cutting tool

Science.gov (United States)

Bhapkar, Rohit Arun; Larsen, Eric Richard

2015-03-31

A combined method of machining and applying a surface texture to a work piece and a tool assembly that is capable of machining and applying a surface texture to a work piece are disclosed. The disclosed method includes machining portions of an outer or inner surface of a work piece. The method also includes rotating the work piece in front of a rotating cutting tool and engaging the outer surface of the work piece with the rotating cutting tool to cut dimples in the outer surface of the work piece. The disclosed tool assembly includes a rotating cutting tool coupled to an end of a rotational machining device, such as a lathe. The same tool assembly can be used to both machine the work piece and apply a surface texture to the work piece without unloading the work piece from the tool assembly.

Magnetostrictive energy generator for harvesting the rotation of human knee joint

Directory of Open Access Journals (Sweden)

Baiping Yan

2018-05-01

Full Text Available This paper presents the design and fabrication of a rotary-impact magnetostrictive energy generator, used to harvest the rotation of human knee joint. The harvester consists of twelve movable Terfenol-D rods, surrounded by the picked up coils respectively, and alternate permanent magnet (PM array sandwiched in each part of the shell. Rotational electromagnetic power generating effect and impacted magnetostrictive power generating effect are designed in the harvester. Modeling and simulation are used to validate the concept. Then, magnetic field and leakage of the harvester are analyzed, electromagnetic force in the harvester is simulated. A prototype of harvester is fabricated, and subjected to the experimental characterization. It can be concluded that huge induced voltage generated in the short-time impact situation and that induced voltage in the harvester can reach up to 60-80 volts at 0.91Hz low frequency rotation. Also, the presented harvester has good harvesting effects at low frequency human walking and periodic swing crus situation, which are suitable to be used for future researches of wearable knee joint applications.

Magnetostrictive energy generator for harvesting the rotation of human knee joint

Science.gov (United States)

Yan, Baiping; Zhang, Chengming; Li, Liyi

2018-05-01

This paper presents the design and fabrication of a rotary-impact magnetostrictive energy generator, used to harvest the rotation of human knee joint. The harvester consists of twelve movable Terfenol-D rods, surrounded by the picked up coils respectively, and alternate permanent magnet (PM) array sandwiched in each part of the shell. Rotational electromagnetic power generating effect and impacted magnetostrictive power generating effect are designed in the harvester. Modeling and simulation are used to validate the concept. Then, magnetic field and leakage of the harvester are analyzed, electromagnetic force in the harvester is simulated. A prototype of harvester is fabricated, and subjected to the experimental characterization. It can be concluded that huge induced voltage generated in the short-time impact situation and that induced voltage in the harvester can reach up to 60-80 volts at 0.91Hz low frequency rotation. Also, the presented harvester has good harvesting effects at low frequency human walking and periodic swing crus situation, which are suitable to be used for future researches of wearable knee joint applications.

Production of Short-Rotation Woody Crops Grown with a Range of Nutrient and Water Availability: Establishment Report and First-Year Responses

Energy Technology Data Exchange (ETDEWEB)

D.R. Coyle; J. Blake; K. Britton; M.; R.G. Campbell; J. Cox; B. Cregg; D. Daniels; M. Jacobson; K. Johnsen; T. McDonald; K. McLeod; E.; D. Robison; R. Rummer; F. Sanchez; J.; B. Stokes; C. Trettin; J. Tuskan; L. Wright; S. Wullschleger

2003-12-31

Coleman, M.D., et. al. 2003. Production of Short-Rotation Woody Crops Grown with a Range of Nutrient and Water Availability: Establishment Report and First-Year Responses. Report. USDA Forest Service, Savannah River, Aiken, SC. 26 pp. Abstract: Many researchers have studied the productivity potential of intensively managed forest plantations. However, we need to learn more about the effects of fundamental growth processes on forest productivity; especially the influence of aboveground and belowground resource acquisition and allocation. This report presents installation, establishment, and first-year results of four tree species (two cottonwood clones, sycamore, sweetgum, and loblolly pine) grown with fertilizer and irrigation treatments. At this early stage of development, irrigation and fertilization were additive only in cottonwood clone ST66 and sweetgum. Leaf area development was directly related to stem growth, but root production was not always consistent with shoot responses, suggesting that allocation of resources varies among treatments. We will evaluate the consequences of these early responses on resource availability in subsequent growing seasons. This information will be used to: (1) optimize fiber and bioenergy production; (2) understand carbon sequestration; and (3) develop innovative applications such as phytoremediation; municipal, industrial, and agricultural wastes management; and protection of soil, air, and water resources.

Decrease in Accuracy of a Rotational SINS Caused by its Rotary Table's Errors

Directory of Open Access Journals (Sweden)

Pin Lv

2014-05-01

Full Text Available We call a strapdown inertial navigation system (SINS that uses the rotation auto-compensation technique (which is a common method to reduce the effect of the bias errors of inertial components a ‘rotational SINS’. In a rotational SINS, the rotary table is an important component, rotating the inertial sensor assembly back and forth in azimuth to accomplish error modulation. As a consequence of the manufacturing process, errors may exist in rotary tables which decrease the navigation accuracy of rotational SINSs. In this study, the errors of rotary tables are considered in terms of installation error, wobble error and angular error, and the models of these errors are established for the rotational SINS. Next, the propagation characteristics of these errors in the rotational SINS are analysed and their effects on navigation results are discussed. Finally, the theoretical conclusions are tested by numerical simulation. This paper supplies a good reference for the development of low-cost rotational SINSs, which usually have low accuracy rotary tables and which may be used in robots, intelligent vehicles and unmanned aerial vehicles (UAVs.

Supination external rotation ankle fractures: A simpler pattern with better outcomes

Science.gov (United States)

Tejwani, Nirmal C; Park, Ji Hae; Egol, Kenneth A

2015-01-01

Background: Rotational injuries are the most common and usually classified as per the Lauge Hansen classification; with the most common subgroup being the supination external rotation (SER) mechanism. Isolated fractures of the distal fibula (SE2) without associated ligamentous injury are usually treated with a splint or brace and the patient may be allowed to weight bear as tolerated. This study reports the functional outcomes following a stable, low energy, rotational ankle fracture supination external rotation (SER2) when compared to unstable SER4 fractures treated operatively. Materials and Methods: 64 patients who were diagnosed and treated nonoperatively for a stable SER2 ankle fracture were followed prospectively. In the comparison group, 93 operatively treated fibular fractures were extracted from a prospectively collected database and evaluated comparison. Baseline characteristics obtained by trained interviewers at the time of injury included: Patient demographics, short form-36, short musculoskeletal functional assessment (SMFA) and American Orthopedic Foot and Ankle Society (AOFAS) questionnaires. Patients were followed at 3, 6 and 12 months postsurgery. Additional information obtained at each followup point included any complications or evidence on fracture healing. Data were analyzed by the Student's t-test and theFisher's Exact Test to compare demographic and functional outcomes between the two cohorts. P fracture cohort was 43 versus 45 in the SER4 group. Nearly 64% of the patient population was female when compared with 37% in the operative group. In the SER2 by 6 months all patients had returned to baseline functional status. There were 18 delayed unions (all healed by 6 months). Based on the functional outcome scores all patients had returned to preoperative level. In comparison, SE4 patients had less functional recovery at 3 and 6 months (P delayed unions. Conclusions: An SER2 ankle fracture is a relatively benign injury with functional

The rotating universe

International Nuclear Information System (INIS)

Ruben, G.; Treder, H.J.

1987-01-01

For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

Rotation sensor switch

International Nuclear Information System (INIS)

Sevec, J.B.

1978-01-01

A protective device to provide a warning if a piece of rotating machinery slows or stops is comprised of a pair of hinged weights disposed to rotate on a rotating shaft of the equipment. When the equipment is rotating, the weights remain in a plane essentially perpendicular to the shaft and constitute part of an electrical circuit that is open. When the shaft slows or stops, the weights are attracted to a pair of concentric electrically conducting disks disposed in a plane perpendicular to the shaft and parallel to the plane of the weights when rotating. A disk magnet attracts the weights to the electrically conducting plates and maintains the electrical contact at the plates to complete an electrical circuit that can then provide an alarm signal

Preliminary Results of a Consecutive Series of Large & Massive Rotator Cuff Tears Treated with Arthroscopic Rotator Cuff Repairs Augmented with Extracellular Matrix

Directory of Open Access Journals (Sweden)

Paolo Consigliere

2017-01-01

Full Text Available Background: Recurrence rate of rotator cuff tears is still high despite the improvements of surgical techniques, materials used and a better knowledge of the healing process of the rotator cuff tendons. Large to massive rotator cuff tears are particularly associated with a high failure rate, especially in elderly. Augmentation of rotator cuff repairs with extracellular matrix or synthetic patches has gained popularity in recent years with the aim of reducing failure.The aim of this study was to investigate the outcome of rotator cuff repairs augmented with denatured extracellular matrix in a series of patients who underwent arthroscopic rotator cuff repair for large to massive tears.Methods: Ten consecutive patients, undergoing arthroscopic rotator cuff repair with extracellular matrix augment for large and massive tears, were prospectively enrolled into this single surgeon study. All repairs were performed arthroscopically with a double row technique augmented with extracellular matrix. Oxford Shoulder Score, Constant Score and pain visual analogue scale (VAS were used to monitor the shoulder function and outcome pre-operatively and at three, six and 12-month follow-up. Minimum follow up was tree months. Mean follow up was 7 months.Results: Mean Constant score improved from 53 (SD=4 pre-operatively to 75 (SD=11 at final follow up. Mean Oxford score also increased from 30 (SD=8 pre-operatively to 47 (SD=10 at the final follow up. The visual analogue scale (VAS improved from seven out of 10 (SD=2 preoperatively to 0.6 (SD=0.8 at final follow up. Additionally, there was significant improvement at three months mark in Constant score. Conclusion: Arthroscopic repair and augmentation of large and massive rotator cuff tears with extracellular matrix patch has good early outcome.

Plasma rotation and rf heating in DIII-D

International Nuclear Information System (INIS)

DeGrassie, J.S.; Baker, D.R.; Burrell, K.H.

1999-05-01

In a variety of discharge conditions on DIII-D it is observed that rf electron heating reduces the toroidal rotation speed and core ion temperature. The rf heating can be with either fast wave or electron cyclotron heating and this effect is insensitive to the details of the launched toroidal wavenumber spectrum. To date all target discharges have rotation first established with co-directed neutral beam injection. A possible cause is enhanced ion momentum and thermal diffusivity due to electron heating effectively creating greater anomalous viscosity. Another is that a counter directed toroidal force is applied to the bulk plasma via rf driven radial current

Plasma rotation and rf heating in DIII-D

International Nuclear Information System (INIS)

Grassie, J. S. de; Baker, D. R.; Burrell, K. H.; Greenfield, C. M.; Lin-Liu, Y. R.; Luce, T. C.; Petty, C. C.; Prater, R.; Heidbrink, W. W.; Rice, B. W.

1999-01-01

In a variety of discharge conditions on DIII-D it is observed that rf electron heating reduces the toroidal rotation speed and core ion temperature. The rf heating can be with either fast wave or electron cyclotron heating and this effect is insensitive to the details of the launched toroidal wavenumber spectrum. To date all target discharges have rotation first established with co-directed neutral beam injection. A possible cause is enhanced ion momentum and thermal diffusivity due to electron heating effectively creating greater anomalous viscosity. Another is that a counter directed toroidal force is applied to the bulk plasma via rf driven radial current. (c) 1999 American Institute of Physics

Characteristics of steady vibration in a rotating hub-beam system

Science.gov (United States)

Zhao, Zhen; Liu, Caishan; Ma, Wei

2016-02-01

A rotating beam features a puzzling character in which its frequencies and modal shapes may vary with the hub's inertia and its rotating speed. To highlight the essential nature behind the vibration phenomena, we analyze the steady vibration of a rotating Euler-Bernoulli beam with a quasi-steady-state stretch. Newton's law is used to derive the equations governing the beam's elastic motion and the hub's rotation. A combination of these equations results in a nonlinear partial differential equation (PDE) that fully reflects the mutual interaction between the two kinds of motion. Via the Fourier series expansion within a finite interval of time, we reduce the PDE into an infinite system of a nonlinear ordinary differential equation (ODE) in spatial domain. We further nondimensionalize the ODE and discretize it via a difference method. The frequencies and modal shapes of a general rotating beam are then determined numerically. For a low-speed beam where the ignorance of geometric stiffening is feasible, the beam's vibration characteristics are solved analytically. We validate our numerical method and the analytical solutions by comparing with either the past experiments or the past numerical findings reported in existing literature. Finally, systematic simulations are performed to demonstrate how the beam's eigenfrequencies vary with the hub's inertia and rotating speed.

Rotationally invariant correlation filtering

International Nuclear Information System (INIS)

Schils, G.F.; Sweeney, D.W.

1985-01-01

A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

The influence of the tangential velocity of inner rotating wall on axial velocity profile of flow through vertical annular pipe with rotating inner surface

Directory of Open Access Journals (Sweden)

Sharf Abdusalam M.

2014-03-01

Full Text Available In the oil and gas industries, understanding the behaviour of a flow through an annulus gap in a vertical position, whose outer wall is stationary whilst the inner wall rotates, is a significantly important issue in drilling wells. The main emphasis is placed on experimental (using an available rig and computational (employing CFD software investigations into the effects of the rotation speed of the inner pipe on the axial velocity profiles. The measured axial velocity profiles, in the cases of low axial flow, show that the axial velocity is influenced by the rotation speed of the inner pipe in the region of almost 33% of the annulus near the inner pipe, and influenced inversely in the rest of the annulus. The position of the maximum axial velocity is shifted from the centre to be nearer the inner pipe, by increasing the rotation speed. However, in the case of higher flow, as the rotation speed increases, the axial velocity is reduced and the position of the maximum axial velocity is skewed towards the centre of the annulus. There is a reduction of the swirl velocity corresponding to the rise of the volumetric flow rate.

Rotation harmonics for a numerical diatomic potential

International Nuclear Information System (INIS)

Kobeissi, H.; Korek, M.

1983-01-01

The problem of the determination of the rotation harmonics phi 1 , phi 2 , ... for the case of a numerical diatomic potential is considered. These harmonics defined in a recent work by psisub(vJ) = psisub(vO) + lambda 2 phi 2 + ... (where psisub(vJ) is the wave function of the vibration level v and the rotation level J, and lambda = J(J+1)) are studied for the case of the Dunham potential and for a numerical potential defined by the coordinates of its turning points with polynomial interpolations and extrapolations. It is proved that the analytical expressions of the harmonics phi 1 , phi 2 , ... reduce to polynomials where the coefficients are simply related to those of the potential in the case of the Dunham potential, and to the coordinates of the turning points in the case of the numerical potential. The numerical application is simple. The examples presented show that the vibration-rotation wave function psisub(vJ) calculated by using two harmonics only is ''exact'' up to eight significant figures

Evidence of nontermination of collective rotation near the maximum angular momentum in Rb75

Science.gov (United States)

Davies, P. J.; Afanasjev, A. V.; Wadsworth, R.; Andreoiu, C.; Austin, R. A. E.; Carpenter, M. P.; Dashdorj, D.; Finlay, P.; Freeman, S. J.; Garrett, P. E.; Görgen, A.; Greene, J.; Grinyer, G. F.; Hyland, B.; Jenkins, D. G.; Johnston-Theasby, F. L.; Joshi, P.; Macchiavelli, A. O.; Moore, F.; Mukherjee, G.; Phillips, A. A.; Reviol, W.; Sarantites, D.; Schumaker, M. A.; Seweryniak, D.; Smith, M. B.; Svensson, C. E.; Valiente-Dobon, J. J.; Ward, D.

2010-12-01

Two of the four known rotational bands in Rb75 were studied via the Ca40(Ca40,αp)Rb75 reaction at a beam energy of 165 MeV. Transitions were observed up to the maximum spin Imax of the assigned configuration in one case and one-transition short of Imax in the other. Lifetimes were determined using the residual Doppler shift attenuation method. The deduced transition quadrupole moments show a small decrease with increasing spin, but remain large at the highest spins. The results obtained are in good agreement with cranked Nilsson-Strutinsky calculations, which indicate that these rotational bands do not terminate, but remain collective at Imax.

Short-rotation coppices. State of the realizability, organisation and a model for the evaluation of the production and supply of rapidly growing wood from short-rotation coppices als a biofuel for biomass-fuelled heating power stations in Bavaria; Kurzumtriebsplantagen. Stand der Umsetzbarkeit, Organisation und ein Modell zur oekonomischen Bewertung von Produktion und Bereitstellung schnell wachsenden Holzes aus Kurzumtriebsplantagen als biogener Festbrennstoff fuer Biomasse(heiz)kraftwerke in Bayern

Energy Technology Data Exchange (ETDEWEB)

Paschlau, Helmut F

2011-04-07

The study examines most aspects of Short-rotation Coppice Crops (SRC), mainly from willows (Salix sp.) and poplars (Populus sp.), for energetic use in big biomass powerstations in Bavaria (southern Germany). In addition to the compilation of framework conditions concerning environmental and agrarian politics as well as legal issues, every link in the process chain of SRC will be considered - from planting to harvesting, treatment of the wood chips and Just-in-time delivery to the powerplant - followed by an evaluation of SRC in ecological terms. The basic aim of this study is to evaluate every single link with regard to organisational und economic issues, analysis of relevant markets and to develop a comprehensive calculation model for the amount of annuities of the whole process chain.

Actomyosin contractility rotates the cell nucleus.

Science.gov (United States)

Kumar, Abhishek; Maitra, Ananyo; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V

2014-01-21

The cell nucleus functions amidst active cytoskeletal filaments, but its response to their contractile stresses is largely unexplored. We study the dynamics of the nuclei of single fibroblasts, with cell migration suppressed by plating onto micro-fabricated patterns. We find the nucleus undergoes noisy but coherent rotational motion. We account for this observation through a hydrodynamic approach, treating the nucleus as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and coherence of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be an intrinsic property of cells.

Twin Rotating Coils for Cold Magnetic Measurements of 15 m Long LHC Dipoles

CERN Document Server

Billan, J; Buzio, M; D'Angelo, G; Deferne, G; Dunkel, O; Legrand, P; Rijllart, A; Siemko, A; Sievers, P; Schloss, S; Walckiers, L

2000-01-01

We describe here a new harmonic coil system for the field measurement of the superconducting, twin aperture LHC dipoles and the associated corrector magnets. Besides field measurements the system can be used as an antenna to localize the quench origin. The main component is a 16 m long rotating shaft, made up of 13 ceramic segments, each carrying two tangential coils plus a central radial coil, all working in parallel. The segments are connected with flexible Ti-alloy bellows, allowing the piecewise straight shaft to follow the curvature of the dipole while maintaining high torsional rigidity. At each interconnection the structure is supported by rollers and ball bearings, necessary for the axial movement for installation and for the rotation of the coil during measurement. Two such shafts are simultaneously driven by a twin-rotating unit, thus measuring both apertures of a dipole at the same time. This arrangement allows very short measurement times (typically 10 s) and is essential to perform cold magnetic ...

Aerial Rotation Effects on Vertical Jump Performance Among Highly Skilled Collegiate Soccer Players.

Science.gov (United States)

Barker, Leland A; Harry, John R; Dufek, Janet S; Mercer, John A

2017-04-01

Barker, LA, Harry, JR, Dufek, JS, and Mercer, JA. Aerial rotation effects on vertical jump performance among highly skilled collegiate soccer players. J Strength Cond Res 31(4): 932-938, 2017-In soccer matches, jumps involving rotations occur when attempting to head the ball for a shot or pass from set pieces, such as corner kicks, goal kicks, and lob passes. However, the 3-dimensional ground reaction forces used to perform rotational jumping tasks are currently unknown. Therefore, the purpose of this study was to compare bilateral, 3-dimensional, and ground reaction forces of a standard countermovement jump (CMJ0) with those of a countermovement jump with a 180° rotation (CMJ180) among Division-1 soccer players. Twenty-four participants from the soccer team of the University of Nevada performed 3 trials of CMJ0 and CMJ180. Dependent variables included jump height, downward and upward phase times, vertical (Fz) peak force and net impulse relative to mass, and medial-lateral and anterior-posterior force couple values. Statistical significance was set a priori at α = 0.05. CMJ180 reduced jump height, increased the anterior-posterior force couple in the downward and upward phases, and increased upward peak Fz (p ≤ 0.05). All other variables were not significantly different between groups (p > 0.05). However, we did recognize that downward peak Fz trended lower in the CMJ0 condition (p = 0.059), and upward net impulse trended higher in the CMJ0 condition (p = 0.071). It was concluded that jump height was reduced during the rotational jumping task, and rotation occurred primarily via AP ground reaction forces through the entire countermovement jump. Coaches and athletes may consider additional rotational jumping in their training programs to mediate performance decrements during rotational jump tasks.

Management of persistent occiput posterior position: a substantial role of instrumental rotation in the setting of failed manual rotation.

Science.gov (United States)

Guerby, Paul; Allouche, Mickael; Simon-Toulza, Caroline; Vayssiere, Christophe; Parant, Olivier; Vidal, Fabien

2018-01-01

To compare the maternal and neonatal outcomes associated with Instrumental Rotation (IR) to operative vaginal delivery in occiput posterior (OP) position with Thierry's spatulas (TS), in the setting of failed manual rotation (MR). We led a prospective observational cohort study in a tertiary referral hospital in Toulouse, France. All women presenting in labor with persistent OP position at full cervical dilatation and who delivered vaginally after failed MR and with IR or OP assisted delivery were included from January 2014 to December 2015. The main outcomes measured were maternal morbidity parameters including episiotomy rate, incidence and severity of perineal lacerations, perineal hematomas and postpartum hemorrhage. Severe perineal tears corresponded to third and fourth degree lacerations. Fetal morbidity outcomes comprised neonatal Apgar scores, acidemia, fetal injuries, birth trauma and neonatal intensive care unit admissions. Among 9762 women, 910 (9.3%) presented with persistent OP position at full cervical dilatation and 222 deliveries were enrolled. Of 111 attempted IR, 97 were successful (87.4%). The incidence of anal sphincter injuries was significantly reduced after IR attempt (1.8% vs. 12.6%; p manual rotation.

Elytra boost lift, but reduce aerodynamic efficiency in flying beetles.

Science.gov (United States)

Johansson, L Christoffer; Engel, Sophia; Baird, Emily; Dacke, Marie; Muijres, Florian T; Hedenström, Anders

2012-10-07

Flying insects typically possess two pairs of wings. In beetles, the front pair has evolved into short, hardened structures, the elytra, which protect the second pair of wings and the abdomen. This allows beetles to exploit habitats that would otherwise cause damage to the wings and body. Many beetles fly with the elytra extended, suggesting that they influence aerodynamic performance, but little is known about their role in flight. Using quantitative measurements of the beetle's wake, we show that the presence of the elytra increases vertical force production by approximately 40 per cent, indicating that they contribute to weight support. The wing-elytra combination creates a complex wake compared with previously studied animal wakes. At mid-downstroke, multiple vortices are visible behind each wing. These include a wingtip and an elytron vortex with the same sense of rotation, a body vortex and an additional vortex of the opposite sense of rotation. This latter vortex reflects a negative interaction between the wing and the elytron, resulting in a single wing span efficiency of approximately 0.77 at mid downstroke. This is lower than that found in birds and bats, suggesting that the extra weight support of the elytra comes at the price of reduced efficiency.

Willow Short Rotation Coppice Trial in a Former Mining Area in Northern Spain: Effects of Clone, Fertilization and Planting Density on Yield after Five Years

Directory of Open Access Journals (Sweden)

María Castaño-Díaz

2018-03-01

Full Text Available A willow short rotation coppice (SRC trial was conducted on former mining land in northern Spain over a period of five years, with the purpose of evaluating the effects on yield of two planting densities (9876 and 14,815 cuttings ha−1, three treatments (control, two levels of nitrogen, phosphorus and potassium compound fertilizer (NPK plus weed control and three willow clones (Björn, Inger, Olof. The area was subsoiled, ploughed, harrowed and fertilized with NPK before trial establishment. A randomized block design was applied, with three replications of each treatment in a total of 54 plots, each of an area of 400 m2. The effects of the interactions between the various factors on yield and other growth parameters were also studied. The clone factor significantly affected the number of shoots per stool (greatest for the Inger clone and the Olof clone, which showed the lowest mortality rate and produced the largest trees and largest quantity of biomass. The combined application of fertilizer and herbicide also significantly increased the values of all response variables considered, except the mortality rate. The planting density did not significantly affect the response variables. Clone × treatment interactions were significant for the shoots per stool, height, diameter and biomass variables, and the Olof clone displayed the highest height and diameter growth and yield. The results obtained in the first rotation indicate that the Olof clone adapted well to the trial conditions and therefore would be appropriate for producing biomass in abandoned mine land in Asturias. These findings will help in the development of strategies for the establishment and management of SRC on marginal land.

NH3 quantum rotators in Hofmann clathrates: intensity and width of rotational transition lines

International Nuclear Information System (INIS)

Vorderwisch, Peter; Sobolev, Oleg; Desmedt, Arnaud

2004-01-01

Inelastic structure factors for rotational transitions of uniaxial NH 3 quantum rotators, measured in a Hofmann clathrate with biphenyl as guest molecule, agree with those calculated for free rotators. A finite intrinsic line width, found for rotational transitions involving the rotational level j=3 at low temperature, supports a recently suggested model based on resonant rotor-rotor coupling

Rotation Frequencies of Small Jovian Trojan Asteroids: An Excess of Slow Rotators

Science.gov (United States)

French, Linda M.; Stephens, Robert D.; James, David J.; Coley, Daniel; Connour, Kyle

2015-11-01

Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half the 131 objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015).A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004).Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

How are arbuscular mycorrhizal associations related to maize growth performance during short-term cover crop rotation?

Science.gov (United States)

Higo, Masao; Takahashi, Yuichi; Gunji, Kento; Isobe, Katsunori

2018-03-01

Better cover crop management options aiming to maximize the benefits of arbuscular mycorrhizal fungi (AMF) to subsequent crops are largely unknown. We investigated the impact of cover crop management methods on maize growth performance and assemblages of AMF colonizing maize roots in a field trial. The cover crop treatments comprised Italian ryegrass, wheat, brown mustard and fallow in rotation with maize. The diversity of AMF communities among cover crops used for maize management was significantly influenced by the cover crop and time course. Cover crops did not affect grain yield and aboveground biomass of subsequent maize but affected early growth. A structural equation model indicated that the root colonization, AMF diversity and maize phosphorus uptake had direct strong positive effects on yield performance. AMF variables and maize performance were related directly or indirectly to maize grain yield, whereas root colonization had a positive effect on maize performance. AMF may be an essential factor that determines the success of cover crop rotational systems. Encouraging AMF associations can potentially benefit cover cropping systems. Therefore, it is imperative to consider AMF associations and crop phenology when making management decisions. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Alignments of multi-quasiparticle bands and seniority-dependent reduced pairing

International Nuclear Information System (INIS)

Dracoulis, G.D.

1994-09-01

Pairing correlations in multi-quasiparticle states in deformed nuclei are expected to be reduced because of blocking. New intrinsic states and their associated rotational bands have been identified allowing comparisons to be made as a function of seniority and between nuclei. The possible effects of the reduced pairing on the collective rotation, and its manifestation in terms of alignment, are discussed. 13 refs., 2 figs

Short video interventions to reduce mental health stigma: a multi-centre randomised controlled trial in nursing high schools.

Science.gov (United States)

Winkler, Petr; Janoušková, Miroslava; Kožený, Jiří; Pasz, Jiří; Mladá, Karolína; Weissová, Aneta; Tušková, Eva; Evans-Lacko, Sara

2017-12-01

We aimed to assess whether short video interventions could reduce stigma among nursing students. A multi-centre, randomised controlled trial was conducted. Participating schools were randomly selected and randomly assigned to receive: (1) an informational leaflet, (2) a short video intervention or (3) a seminar involving direct contact with a service user. The Community Attitudes towards Mental Illness (CAMI) and Reported and Intended Behaviour Scale (RIBS) were selected as primary outcome measures. SPANOVA models were built and Cohen's d calculated to assess the overall effects in each of the trial arms. Compared to the baseline, effect sizes immediately after the intervention were small in the flyer arm (CAMI: d = 0.25; RIBS: d = 0.07), medium in the seminar arm (CAMI: d = 0.61; RIBS: d = 0.58), and medium in the video arm (CAMI: d = 0.49 RIBS: d = 0.26; n = 237). Effect sizes at the follow-up were vanishing in the flyer arm (CAMI: d = 0.05; RIBS: d = 0.04), medium in the seminar arm (CAMI: d = 0.43; RIBS: d = 0.26; n = 254), and small in the video arm (CAMI: d = 0.22 RIBS: d = 0.21; n = 237). Seminar had the strongest and relatively stable effect on students' attitudes and intended behaviour, but the effect of short video interventions was also considerable and stable over time. Since short effective video interventions are relatively cheap, conveniently accessible and easy to disseminate globally, we recommend them for further research and development.

Reynolds-Stress and Triple-Product Models Applied to a Flow with Rotation and Curvature

Science.gov (United States)

Olsen, Michael E.

2016-01-01

Turbulence models, with increasing complexity, up to triple product terms, are applied to the flow in a rotating pipe. The rotating pipe is a challenging case for turbulence models as it contains significant rotational and curvature effects. The flow field starts with the classic fully developed pipe flow, with a stationary pipe wall. This well defined condition is then subjected to a section of pipe with a rotating wall. The rotating wall introduces a second velocity scale, and creates Reynolds shear stresses in the radial-circumferential and circumferential-axial planes. Furthermore, the wall rotation introduces a flow stabilization, and actually reduces the turbulent kinetic energy as the flow moves along the rotating wall section. It is shown in the present work that the Reynolds stress models are capable of predicting significant reduction in the turbulent kinetic energy, but triple product improves the predictions of the centerline turbulent kinetic energy, which is governed by convection, dissipation and transport terms, as the production terms vanish on the pipe axis.

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1977-01-01

History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

Rotations with Rodrigues' vector

International Nuclear Information System (INIS)

Pina, E

2011-01-01

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

Effect of rotation on convective mass transfer in rotating channels

International Nuclear Information System (INIS)

Pharoah, J.G.; Djilali, N.

2002-01-01

Laminar flow and mass transfer in rotating channels is investigated in the context of centrifugal membrane separation. The effect of orientation with respect to the rotational axis is examined for rectangular channels of aspect ratio 3 and the Rossby number is varied from 0.3 to 20.9. Both Ro and the channel orientation are found to have a significant effect on the flow. Mass transfer calculations corresponding to reverse osmosis desalination are carried out at various operating pressures and all rotating cases exhibit significant process enhancements at relatively low rotation rates. Finally, while it is common in the membrane literature to correlate mass transfer performance with membrane shear rates this is shown not to be valid in the cases presented herein. (author)

Rotating UPS installations and dynamic energy storage. Comparison of static and rotating UPS and comparison of dynamic energy storage using batteries - Final Report; Rotierende USV-Anlagen und dynamische Energiespeicherung. Vergleich der statischen mit rotierenden USV-Anlagen und Vergleich der dynamischen Energiespeicherung mit Batterieanlagen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Mauchle, P.; Schnyder, G.

2010-01-15

As an alternative to the static UPS-Systems (uninterruptible power supply systems), rotating UPS-Systems can be applied. The application and the realisation of rotating UPS-Systems are different to the one of static UPS-Systems. Furthermore at the rotating UPS-Systems is to distinguish, if the UPS-System is realised as a diesel dynamic UPS-System, with an activity up from 400 kVA, or if the dynamic part is limited to the energy storage, with an activity up from 60 kVA. The diesel dynamic UPS-Systems are composed of a synchronous machine, an asynchronous machine with a flywheel, respectively a kinetic module and the diesel engine. The connection to the critical user at the low voltage network occurs using an inductor and the accordant switchgears. The application of a diesel dynamic UPS-System is optimal when it can be connected with an emergency power supply. With the realisation of dynamic energy storages, battery systems can be avoided respectively can be reduced or the lifetime of batteries can be extended. It is only possible to avoid the batteries if the requested autonomous time of the UPS-System is shorter than two minutes. Is an autonomous time longer than 2 minutes necessary, battery systems have to be realised for the energy storage. Thereby dynamic energy storage in parallel to the battery system is useful, because the dynamic energy storage will compensate temporary voltage drops or short power failures. In this way the number of charge and discharge cycles of the battery system will be reduced and therefore the lifetime of the battery will be extended. The use of a dynamic or static UPS system is dependent on the requirements of the powered load. Taking into account various criteria it can be found for each specific application the optimal type of UPS system. (authors)

Mass Distribution in Rotating Thin-Disk Galaxies According to Newtonian Dynamics

Directory of Open Access Journals (Sweden)

James Q. Feng

2014-04-01

Full Text Available An accurate computational method is presented for determining the mass distribution in a mature spiral galaxy from a given rotation curve by applying Newtonian dynamics for an axisymmetrically rotating thin disk of finite size with or without a central spherical bulge. The governing integral equation for mass distribution is transformed via a boundary-element method into a linear algebra matrix equation that can be solved numerically for rotation curves with a wide range of shapes. To illustrate the effectiveness of this computational method, mass distributions in several mature spiral galaxies are determined from their measured rotation curves. All the surface mass density profiles predicted by our model exhibit approximately a common exponential law of decay, quantitatively consistent with the observed surface brightness distributions. When a central spherical bulge is present, the mass distribution in the galaxy is altered in such a way that the periphery mass density is reduced, while more mass appears toward the galactic center. By extending the computational domain beyond the galactic edge, we can determine the rotation velocity outside the cut-off radius, which appears to continuously decrease and to gradually approach the Keplerian rotation velocity out over twice the cut-off radius. An examination of circular orbit stability suggests that galaxies with flat or rising rotation velocities are more stable than those with declining rotation velocities especially in the region near the galactic edge. Our results demonstrate the fact that Newtonian dynamics can be adequate for describing the observed rotation behavior of mature spiral galaxies.

Earth Rotation

Science.gov (United States)

Dickey, Jean O.

1995-01-01

The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

Rotational 3D printing of damage-tolerant composites with programmable mechanics.

Science.gov (United States)

Raney, Jordan R; Compton, Brett G; Mueller, Jochen; Ober, Thomas J; Shea, Kristina; Lewis, Jennifer A

2018-02-06

Natural composites exhibit exceptional mechanical performance that often arises from complex fiber arrangements within continuous matrices. Inspired by these natural systems, we developed a rotational 3D printing method that enables spatially controlled orientation of short fibers in polymer matrices solely by varying the nozzle rotation speed relative to the printing speed. Using this method, we fabricated carbon fiber-epoxy composites composed of volume elements (voxels) with programmably defined fiber arrangements, including adjacent regions with orthogonally and helically oriented fibers that lead to nonuniform strain and failure as well as those with purely helical fiber orientations akin to natural composites that exhibit enhanced damage tolerance. Our approach broadens the design, microstructural complexity, and performance space for fiber-reinforced composites through site-specific optimization of their fiber orientation, strain, failure, and damage tolerance. Copyright © 2018 the Author(s). Published by PNAS.

Rotated alphanumeric characters do not automatically activate frontoparietal areas subserving mental rotation

DEFF Research Database (Denmark)

Weiss, Michael M; Wolbers, Thomas; Peller, Martin

2008-01-01

Functional neuroimaging studies have identified a set of areas in the intraparietal sulcus and dorsal precentral cortex which show a linear increase in activity with the angle of rotation across a variety of mental rotation tasks. This linear increase in activity with angular disparity suggests t...... modulated by angular disparity during the stimulus categorization task. These results suggest that at least for alphanumerical characters, areas implicated in mental rotation will only be called into action if the task requires a rotational transformation....

Rotating dryer

International Nuclear Information System (INIS)

Noe, C.

1984-01-01

Products to dry are introduced inside a rotating tube placed in an oven, the cross section of the tube is an arc of spiral. During clockwise rotation of the tube products are maintained inside and mixed, during anticlockwise products are removed. Application is made to drying of radioactive wastes [fr

Rotating Wavepackets

Science.gov (United States)

Lekner, John

2008-01-01

Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

Rotator cuff - self-care

Science.gov (United States)

... this page: //medlineplus.gov/ency/patientinstructions/000358.htm Rotator cuff - self-care To use the sharing features on ... and shoulder exercises may help ease your symptoms. Rotator Cuff Problems Common rotator cuff problems include: Tendinitis , which ...

The Effects of Cattle Manure and Garlic Rotation on Soil under Continuous Cropping of Watermelon (Citrullus lanatus L.).

Science.gov (United States)

Yang, Ruiping; Mo, Yanling; Liu, Changming; Wang, Yongqi; Ma, Jianxiang; Zhang, Yong; Li, Hao; Zhang, Xian

2016-01-01

Continuous cropping of watermelon (Citrullus lanatus L.) can lead to reduced yield and quality. We aimed to determine the effects of cattle manure addition and rotation with green garlic to improve yield and reduce disease incidence in watermelon and to examine the effects on the biological and chemical characteristics of the soil. Field experiments were performed during 2012-2014 on land previously under two years of continuous watermelon cropping in northwest China. We examined three treatment combinations: watermelon and garlic rotation, cattle manure application before watermelon planting, and combined cattle manure addition and crop rotation. Watermelon monoculture was retained as a control. Watermelon yield was significantly higher and disease incidence was lower in the treatments than the control. The populations of soil bacteria and actinomycetes and the bacteria/fungi ratio increased significantly and soil enzyme activities were generally enhanced under treatments. Available nutrients and soil organic matter contents were much higher under experimental treatments than the control. Results suggest both cattle manure application and garlic rotation can ameliorate the negative effects of continuous cropping. The combined treatment of cattle manure addition and green garlic rotation was optimal to increase yield, reduce disease incidence and enhance soil quality.

M-dwarf rapid rotators and the detection of relatively young multiple M-star systems

International Nuclear Information System (INIS)

Rappaport, S.; Joss, M.; Sanchis-Ojeda, R.

2014-01-01

We have searched the Kepler light curves of ∼3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms, inspection of folded light curves, 'sonograms', and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P rot , of <2 days, and 110 with P rot < 1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have 3 or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M stars, this could prove a valuable way discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ∼5% occurrence rate of rapid rotation among the ∼3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.

Adapting crop rotations to climate change in regional impact modelling assessments.

Science.gov (United States)

Teixeira, Edmar I; de Ruiter, John; Ausseil, Anne-Gaelle; Daigneault, Adam; Johnstone, Paul; Holmes, Allister; Tait, Andrew; Ewert, Frank

2018-03-01

The environmental and economic sustainability of future cropping systems depends on adaptation to climate change. Adaptation studies commonly rely on agricultural systems models to integrate multiple components of production systems such as crops, weather, soil and farmers' management decisions. Previous adaptation studies have mostly focused on isolated monocultures. However, in many agricultural regions worldwide, multi-crop rotations better represent local production systems. It is unclear how adaptation interventions influence crops grown in sequences. We develop a catchment-scale assessment to investigate the effects of tactical adaptations (choice of genotype and sowing date) on yield and underlying crop-soil factors of rotations. Based on locally surveyed data, a silage-maize followed by catch-crop-wheat rotation was simulated with the APSIM model for the RCP 8.5 emission scenario, two time periods (1985-2004 and 2080-2100) and six climate models across the Kaituna catchment in New Zealand. Results showed that direction and magnitude of climate change impacts, and the response to adaptation, varied spatially and were affected by rotation carryover effects due to agronomical (e.g. timing of sowing and harvesting) and soil (e.g. residual nitrogen, N) aspects. For example, by adapting maize to early-sowing dates under a warmer climate, there was an advance in catch crop establishment which enhanced residual soil N uptake. This dynamics, however, differed with local environment and choice of short- or long-cycle maize genotypes. Adaptation was insufficient to neutralize rotation yield losses in lowlands but consistently enhanced yield gains in highlands, where other constraints limited arable cropping. The positive responses to adaptation were mainly due to increases in solar radiation interception across the entire growth season. These results provide deeper insights on the dynamics of climate change impacts for crop rotation systems. Such knowledge can be used

Examining cotton in rotation with rice and cotton in rotation with other crops using natural experiment

Science.gov (United States)

Sun, Ling; Zhu, Zesheng

2017-08-01

This paper is to show the ability of remote sensing image analysis combined with statistical analysis to characterize the environmental risk assessment of cotton in rotation with rice and cotton in rotation with other crops in two ways: (1) description of rotation period of cotton in rotation with rice and cotton in rotation with other crops by the observational study or natural experiment; (2) analysis of rotation period calculation of cotton in rotation with rice and cotton in rotation with other crops. Natural experimental results show that this new method is very promising for determining crop rotation period for estimating regional averages of environmental risk. When it is applied to determining crop rotation period, two requested remote sensing images of regional crop are required at least.

Analysis of rotation-vibration relative equilibria on the example of a tetrahedral four atom molecule

NARCIS (Netherlands)

Efstathiou, K; Sadovskii, DA; Zhilinskii, BI

2004-01-01

We study relative equilibria ( RE) of a nonrigid molecule, which vibrates about a well-defined equilibrium configuration and rotates as a whole. Our analysis unifies the theory of rotational and vibrational RE. We rely on the detailed study of the symmetry group action on the initial and reduced

ROTATIONAL VARIABILITY OF EARTH'S POLAR REGIONS: IMPLICATIONS FOR DETECTING SNOWBALL PLANETS

International Nuclear Information System (INIS)

Cowan, Nicolas B.; Robinson, Tyler; Agol, Eric; Meadows, Victoria S.; Shields, Aomawa L.; Livengood, Timothy A.; Deming, Drake; A'Hearn, Michael F.; Wellnitz, Dennis D.; Charbonneau, David; Lisse, Carey M.; Seager, Sara

2011-01-01

We have obtained the first time-resolved, disk-integrated observations of Earth's poles with the Deep Impact spacecraft as part of the EPOXI mission of opportunity. These data mimic what we will see when we point next-generation space telescopes at nearby exoplanets. We use principal component analysis (PCA) and rotational light curve inversion to characterize color inhomogeneities and map their spatial distribution from these unusual vantage points, as a complement to the equatorial views presented by Cowan et al. in 2009. We also perform the same PCA on a suite of simulated rotational multi-band light curves from NASA's Virtual Planetary Laboratory three-dimensional spectral Earth model. This numerical experiment allows us to understand what sorts of surface features PCA can robustly identify. We find that the EPOXI polar observations have similar broadband colors as the equatorial Earth, but with 20%-30% greater apparent albedo. This is because the polar observations are most sensitive to mid-latitudes, which tend to be more cloudy than the equatorial latitudes emphasized by the original EPOXI Earth observations. The cloudiness of the mid-latitudes also manifests itself in the form of increased variability at short wavelengths in the polar observations and as a dominant gray eigencolor in the south polar observation. We construct a simple reflectance model for a snowball Earth. By construction, our model has a higher Bond albedo than the modern Earth; its surface albedo is so high that Rayleigh scattering does not noticeably affect its spectrum. The rotational color variations occur at short wavelengths due to the large contrast between glacier ice and bare land in those wavebands. Thus, we find that both the broadband colors and diurnal color variations of such a planet would be easily distinguishable from the modern-day Earth, regardless of viewing angle.

Fast MR arthrography using VIBE sequences to evaluate the rotator cuff

Energy Technology Data Exchange (ETDEWEB)

Vandevenne, Jan E. [Ziekenhuizen Oost-Limburg, Department of Radiology, Genk (Belgium); Universitair Ziekenhuis Antwerpen, University of Antwerp, Department of Radiology, Edegem (Belgium); Vanhoenacker, Filip; Parizel, Paul M. [Universitair Ziekenhuis Antwerpen, University of Antwerp, Department of Radiology, Edegem (Belgium); Mahachie John, Jestinah M. [University of Hasselt, Centre for Statistics, Diepenbeek (Belgium); Gelin, Geert [Ziekenhuizen Oost-Limburg, Department of Radiology, Genk (Belgium)

2009-07-15

The purpose of this paper was to evaluate if short volumetric interpolated breath-hold examination (VIBE) sequences can be used as a substitute for T1-weighted with fat saturation (T1-FS) sequences when performing magnetic resonance (MR) arthrography to diagnose rotator cuff tears. Eighty-two patients underwent direct MR arthrography of the shoulder joint using VIBE (acquisition time of 13 s) and T1-FS (acquisition time of 5 min) sequences in the axial and paracoronal plane on a 1.0-T MR unit. Two radiologists scored rotator cuff tendons on VIBE and T1-FS images separately as normal, small/large partial thickness and full thickness tears with or without geyser sign. T1-FS sequences were considered the gold standard. Surgical correlation was available in a small sample. Sensitivity, specificity, and positive and negative predictive values of VIBE were greater than 92% for large articular-sided partial thickness and full thickness tears. For detecting fraying and articular-sided small partial thickness tears, these parameters were 55%, 94%, 94%, and 57%, respectively. The simple kappa value was 0.76, and the weighted kappa value was 0.86 for agreement between T1-FS and VIBE scores. All large partial and full thickness tears at surgery were correctly diagnosed using VIBE or T1-FS MR images. Fast MR arthrography of the shoulder joint using VIBE sequences showed good concordance with the classically used T1-FS sequences for the appearance of the rotator cuff, in particular for large articular-sided partial thickness tears and for full thickness tears. Due to its very short acquisition time, VIBE may be especially useful when performing MR arthrography in claustrophobic patients or patients with a painful shoulder. (orig.)

Rotating Stars in Relativity

Directory of Open Access Journals (Sweden)

Stergioulas Nikolaos

2003-01-01

Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

Science.gov (United States)

Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

2012-01-01

Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

Effect of head rotation on cerebral blood velocity in the prone position

DEFF Research Database (Denmark)

Højlund, Jakob; Sandmand, Marie; Sonne, Morten

2012-01-01

for cerebral blood flow. We tested in healthy subjects the hypothesis that rotating the head in the prone position reduces cerebral blood flow. Methods. Mean arterial blood pressure (MAP), stroke volume (SV), and CO were determined, together with the middle cerebral artery mean blood velocity (MCA V...... V(mean) ~10% in spite of an elevated MAP. Prone positioning with rotated head affects both CBF and cerebrovenous drainage indicating that optimal brain perfusion requires head centering....

Correction of rotational distortion for catheter-based en face OCT and OCT angiography

Science.gov (United States)

Ahsen, Osman O.; Lee, Hsiang-Chieh; Giacomelli, Michael G.; Wang, Zhao; Liang, Kaicheng; Tsai, Tsung-Han; Potsaid, Benjamin; Mashimo, Hiroshi; Fujimoto, James G.

2015-01-01

We demonstrate a computationally efficient method for correcting the nonuniform rotational distortion (NURD) in catheter-based imaging systems to improve endoscopic en face optical coherence tomography (OCT) and OCT angiography. The method performs nonrigid registration using fiducial markers on the catheter to correct rotational speed variations. Algorithm performance is investigated with an ultrahigh-speed endoscopic OCT system and micromotor catheter. Scan nonuniformity is quantitatively characterized, and artifacts from rotational speed variations are significantly reduced. Furthermore, we present endoscopic en face OCT and OCT angiography images of human gastrointestinal tract in vivo to demonstrate the image quality improvement using the correction algorithm. PMID:25361133

Rotation-supported Neutrino-driven Supernova Explosions in Three Dimensions and the Critical Luminosity Condition

Science.gov (United States)

Summa, Alexander; Janka, Hans-Thomas; Melson, Tobias; Marek, Andreas

2018-01-01

We present the first self-consistent, 3D core-collapse supernova simulations performed with the PROMETHEUS-VERTEX code for a rotating progenitor star. Besides using the angular momentum of the 15 M ⊙ model as obtained in the stellar evolution calculation with an angular frequency of ∼10‑3 rad s‑1 (spin period of more than 6000 s) at the Si/Si–O interface, we also computed 2D and 3D cases with no rotation and with a ∼300 times shorter rotation period and different angular resolutions. In 2D, only the nonrotating and slowly rotating models explode, while rapid rotation prevents an explosion within 500 ms after bounce because of lower radiated neutrino luminosities and mean energies and thus reduced neutrino heating. In contrast, only the fast-rotating model develops an explosion in 3D when the Si/Si–O interface collapses through the shock. The explosion becomes possible by the support of a powerful standing accretion shock instability spiral mode, which compensates for the reduced neutrino heating and pushes strong shock expansion in the equatorial plane. Fast rotation in 3D leads to a “two-dimensionalization” of the turbulent energy spectrum (yielding roughly a ‑3 instead of a ‑5/3 power-law slope at intermediate wavelengths) with enhanced kinetic energy on the largest spatial scales. We also introduce a generalization of the “universal critical luminosity condition” of Summa et al. to account for the effects of rotation, and we demonstrate its viability for a set of more than 40 core-collapse simulations, including 9 and 20 M ⊙ progenitors, as well as black-hole-forming cases of 40 and 75 M ⊙ stars to be discussed in forthcoming papers.

Self-rotations in simulated microgravity: performance effects of strategy training.

Science.gov (United States)

Stirling, Leia; Newman, Dava; Willcox, Karen

2009-01-01

This research studies reorientation methodologies in a simulated microgravity environment using an experimental framework to reduce astronaut adaptation time and provide for a safety countermeasure during extravehicular activity. There were 20 subjects (10 men, 10 women, mean age of 23.6 +/- 3.5) who were divided into 2 groups, fully trained and minimally trained, which determined the amount of motion strategy training received. Subjects performed a total of 48 rotations about their pitch, roll, and yaw axes in a suspension system that simulated microgravity. In each trial subjects either rotated 90 degrees in pitch, 90 degrees in roll, or 180 degrees in yaw. Experimental measures include subject coordination, performance time, cognitive workload assessments, and qualitative motion control strategies. Subjects in the fully trained group had better initial performance with respect to performance time and workload scores for the pitch and yaw rotations. Further, trained subjects reached a steady-state performance time in fewer trials than those with minimal training. The subjects with minimal training tended to use motions that were common in an Earth environment since no technique was provided. For roll rotations they developed motions that would have led to significant off-axis (pitch and yaw) rotations in a true microgravity environment. We have shown that certain body axes are easier to rotate about than others and that fully trained subjects had an easier time performing the body rotations than the minimally trained subjects. This study has provided the groundwork for the development of an astronaut motion-control training program.

Feedback Control of Resistive Wall Modes in Slowly Rotating DIII-D Plasmas

Science.gov (United States)

Okabayashi, M.; Chance, M. S.; Takahashi, H.; Garofalo, A. M.; Reimerdes, H.; in, Y.; Chu, M. S.; Jackson, G. L.; La Haye, R. J.; Strait, E. J.

2006-10-01

In slowly rotating plasmas on DIII-D, the requirement of RWM control feedback have been identified, using a MHD code along with measured power supply characteristics. It was found that a small time delay is essential for achieving high beta if no rotation stabilization exists. The overall system delay or the band pass time constant should be in the range of 0.4 of the RWM growth time. Recently the control system was upgraded using twelve linear audio amplifiers and a faster digital control system, reducing the time-delay from 600 to 100 μs. The advantage has been clearly observed when the RWMs excited by ELMs were effectively controlled by feedback even if the rotation transiently slowed nearly to zero. This study provides insight on stability in the low- rotation plasmasw with balanced NBI in DIII-D and also in ITER.

Parameterization of rotational spectra

International Nuclear Information System (INIS)

Zhou Chunmei; Liu Tong

1992-01-01

The rotational spectra of the strongly deformed nuclei with low rotational frequencies and weak band mixture are analyzed. The strongly deformed nuclei are commonly encountered in the rare-earth region (e. g., 150 220). A lot of rotational band knowledge are presented

Short-term, high-dose glucocorticoid treatment does not contribute to reduced bone mineral density in patients with multiple sclerosis

DEFF Research Database (Denmark)

Olsson, A.; Oturai, D B; Sørensen, P S

2015-01-01

BACKGROUND: Patients with multiple sclerosis (MS) are at increased risk of reduced bone mineral density (BMD). A contributing factor might be treatment with high-dose glucocorticoids (GCs). OBJECTIVES: The objective of this paper is to assess bone mass in patients with MS and evaluate...... the importance of short-term, high-dose GC treatment and other risk factors that affect BMD in patients with MS. METHODS: A total of 260 patients with MS received short-term high-dose GC treatment and had their BMD measured by dual x-ray absorptiometry. BMD was compared to a healthy age-matched reference...... population (Z-scores). Data regarding GCs, age, body mass index (BMI), serum 25(OH)D, disease duration and severity were collected retrospectively and analysed in a multiple linear regression analysis to evaluate the association between each risk factor and BMD. RESULTS: Osteopenia was present in 38...

Nonlinear model of a rotating hub-beams structure: Equations of motion

Science.gov (United States)

Warminski, Jerzy

2018-01-01

Dynamics of a rotating structure composed of a rigid hub and flexible beams is presented in the paper. A nonlinear model of a beam takes into account bending, extension and nonlinear curvature. The influence of geometric nonlinearity and nonconstant angular velocity on dynamics of the rotating structure is presented. The exact equations of motion and associated boundary conditions are derived on the basis of the Hamilton's principle. The simplification of the exact nonlinear mathematical model is proposed taking into account the second order approximation. The reduced partial differential equations of motion together with associated boundary conditions can be used to study natural or forced vibrations of a rotating structure considering constant or nonconstant angular speed of a rigid hub and an arbitrary number of flexible blades.

Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves.

Science.gov (United States)

Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B; Yu, Hai-Bo

2017-09-15

The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25-300  km/s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

Unsteady flow over a decelerating rotating sphere

Science.gov (United States)

Turkyilmazoglu, M.

2018-03-01

Unsteady flow analysis induced by a decelerating rotating sphere is the main concern of this paper. A revolving sphere in a still fluid is supposed to slow down at an angular velocity rate that is inversely proportional to time. The governing partial differential equations of motion are scaled in accordance with the literature, reducing to the well-documented von Kármán equations in the special circumstance near the pole. Both numerical and perturbation approaches are pursued to identify the velocity fields, shear stresses, and suction velocity far above the sphere. It is detected that an induced flow surrounding the sphere acts accordingly to adapt to the motion of the sphere up to some critical unsteadiness parameters at certain latitudes. Afterward, the decay rate of rotation ceases such that the flow at the remaining azimuths starts revolving freely. At a critical unsteadiness parameter corresponding to s = -0.681, the decelerating sphere rotates freely and requires no more torque. At a value of s exactly matching the rotating disk flow at the pole identified in the literature, the entire flow field around the sphere starts revolving faster than the disk itself. Increasing values of -s almost diminish the radial outflow. This results in jet flows in both the latitudinal and meridional directions, concentrated near the wall region. The presented mean flow results will be useful for analyzing the instability features of the flow, whether of a convective or absolute nature.

Units of rotational information

Science.gov (United States)

Yang, Yuxiang; Chiribella, Giulio; Hu, Qinheping

2017-12-01

Entanglement in angular momentum degrees of freedom is a precious resource for quantum metrology and control. Here we study the conversions of this resource, focusing on Bell pairs of spin-J particles, where one particle is used to probe unknown rotations and the other particle is used as reference. When a large number of pairs are given, we show that every rotated spin-J Bell state can be reversibly converted into an equivalent number of rotated spin one-half Bell states, at a rate determined by the quantum Fisher information. This result provides the foundation for the definition of an elementary unit of information about rotations in space, which we call the Cartesian refbit. In the finite copy scenario, we design machines that approximately break down Bell states of higher spins into Cartesian refbits, as well as machines that approximately implement the inverse process. In addition, we establish a quantitative link between the conversion of Bell states and the simulation of unitary gates, showing that the fidelity of probabilistic state conversion provides upper and lower bounds on the fidelity of deterministic gate simulation. The result holds not only for rotation gates, but also to all sets of gates that form finite-dimensional representations of compact groups. For rotation gates, we show how rotations on a system of given spin can simulate rotations on a system of different spin.

METHOD FOR DETERMINATION OF ROTATION CENTER IN VIBRATING OBJECT

Directory of Open Access Journals (Sweden)

I. P. Kauryha

2016-01-01

Full Text Available Linear piezoelectric gauges, eddy current transducers and other control and measuring devices have been widely applied for vibration diagnostics of objects in industry. Methods based on such gauges and used for measuring angular and linear vibrations do not provide the possibility to assess a rotation center or point angle of an object. Parasitic oscillations may occur during rotor rotation and in some cases the oscillations are caused by dis-balance. The known methods for measuring angular and linear vibrations make it possible to detect the phenomenon and they do not provide information for balancing of the given object. For this very reason the paper describes a method for obtaining instantaneous rotation center in the vibrating object. It allows to improve informational content of the measurements owing to obtaining additional data on position of object rotation center. The obtained data can be used for balancing of a control object. Essence of the given method is shown by an example of piezoelectric gauges of linear vibrations. Two three-axial gauges are fixed to the investigated object. Then gauge output signals are recalculated in angular vibrations of the object (for this purpose it is necessary to know a distance between gauges. Further projection positions of the object rotation center are determined on three orthogonal planes. Instantaneous rotation center is calculated according to the position of one of the gauges. The proposed method permits to obtain data on linear and angular vibrations and rotation center position of the vibrating object using one system of linear gauge. Possibilities of object diagnostics are expanded due to increase in number of determined parameters pertaining to object moving. The method also makes it possible to reduce material and time expenses for measurement of an angular vibration component. 

Short-term, high-dose glucocorticoid treatment does not contribute to reduced bone mineral density in patients with multiple sclerosis.

Science.gov (United States)

Olsson, A; Oturai, D B; Sørensen, P S; Oturai, P S; Oturai, A B

2015-10-01

Patients with multiple sclerosis (MS) are at increased risk of reduced bone mineral density (BMD). A contributing factor might be treatment with high-dose glucocorticoids (GCs). The objective of this paper is to assess bone mass in patients with MS and evaluate the importance of short-term, high-dose GC treatment and other risk factors that affect BMD in patients with MS. A total of 260 patients with MS received short-term high-dose GC treatment and had their BMD measured by dual x-ray absorptiometry. BMD was compared to a healthy age-matched reference population (Z-scores). Data regarding GCs, age, body mass index (BMI), serum 25(OH)D, disease duration and severity were collected retrospectively and analysed in a multiple linear regression analysis to evaluate the association between each risk factor and BMD. Osteopenia was present in 38% and osteoporosis in 7% of the study population. Mean Z-score was significantly below zero, indicating a decreased BMD in our MS patients. Multiple linear regression analysis showed no significant association between GCs and BMD. In contrast, age, BMI and disease severity were independently associated with both lumbar and femoral BMD. Reduced BMD was prevalent in patients with MS. GC treatment appears not to be the primary underlying cause of secondary osteoporosis in MS patients. © The Author(s), 2015.

Magnetic resonance described in the excitation dependent rotating frame of reference.

Science.gov (United States)

Tahayori, Bahman; Johnston, Leigh A; Mareels, Iven M Y; Farrell, Peter M

2008-01-01

An excitation dependent rotating frame of reference to observe the magnetic resonance phenomenon is introduced in this paper that, to the best of our knowledge, has not been used previously in the nuclear magnetic resonance context. The mathematical framework for this new rotating frame of reference is presented based on time scaling the Bloch equation after transformation to the classical rotating frame of reference whose transverse plane is rotating at the Larmor frequency. To this end, the Bloch equation is rewritten in terms of a magnetisation vector observed from the excitation dependent rotating frame of reference. The resultant Bloch equation is referred to as the time scaled Bloch equation. In the excitation dependent rotating frame of reference whose coordinates are rotating at the instantaneous Rabi frequency the observed magnetisation vector is a much slower signal than the true magnetisation in the rotating frame of reference. As a result the ordinary differential equation solvers have the ability to solve the time scaled version of the Bloch equation with a larger step size resulting in a smaller number of samples for solving the equation to a desired level of accuracy. The simulation results for different types of excitation are presented in this paper. This method may be used in true Bloch simulators in order to reduce the simulation time or increase the accuracy of the numerical solution. Moreover, the time scaled Bloch equation may be employed to determine the optimal excitation pattern in magnetic resonance imaging as well as designing pulses with better slice selectivity which is an active area of research in this field.

Rotating reactors : a review

NARCIS (Netherlands)

Visscher, F.; Schaaf, van der J.; Nijhuis, T.A.; Schouten, J.C.

2013-01-01

This review-perspective paper describes the current state-of-the-art in the field of rotating reactors. The paper has a focus on rotating reactor technology with applications at lab scale, pilot scale and industrial scale. Rotating reactors are classified and discussed according to their geometry:

An imaging method of wavefront coding system based on phase plate rotation

Science.gov (United States)

Yi, Rigui; Chen, Xi; Dong, Liquan; Liu, Ming; Zhao, Yuejin; Liu, Xiaohua

2018-01-01

Wave-front coding has a great prospect in extending the depth of the optical imaging system and reducing optical aberrations, but the image quality and noise performance are inevitably reduced. According to the theoretical analysis of the wave-front coding system and the phase function expression of the cubic phase plate, this paper analyzed and utilized the feature that the phase function expression would be invariant in the new coordinate system when the phase plate rotates at different angles around the z-axis, and we proposed a method based on the rotation of the phase plate and image fusion. First, let the phase plate rotated at a certain angle around the z-axis, the shape and distribution of the PSF obtained on the image surface remain unchanged, the rotation angle and direction are consistent with the rotation angle of the phase plate. Then, the middle blurred image is filtered by the point spread function of the rotation adjustment. Finally, the reconstruction images were fused by the method of the Laplacian pyramid image fusion and the Fourier transform spectrum fusion method, and the results were evaluated subjectively and objectively. In this paper, we used Matlab to simulate the images. By using the Laplacian pyramid image fusion method, the signal-to-noise ratio of the image is increased by 19% 27%, the clarity is increased by 11% 15% , and the average gradient is increased by 4% 9% . By using the Fourier transform spectrum fusion method, the signal-to-noise ratio of the image is increased by 14% 23%, the clarity is increased by 6% 11% , and the average gradient is improved by 2% 6%. The experimental results show that the image processing by the above method can improve the quality of the restored image, improving the image clarity, and can effectively preserve the image information.

Design and Test Results of Superconducting Magnet for Heavy-Ion Rotating Gantry

Science.gov (United States)

Takayama, S.; Koyanagi, K.; Miyazaki, H.; Takami, S.; Orikasa, T.; Ishii, Y.; Kurusu, T.; Iwata, Y.; Noda, K.; Obana, T.; Suzuki, K.; Ogitsu, T.; Amemiya, N.

2017-07-01

Heavy-ion radiotherapy has a high curative effect in cancer treatment and also can reduce the burden on patients. These advantages have been generally recognized. Furthermore, a rotating gantry can irradiate a tumor with ions from any direction without changing the position of the patient. This can reduce the physical dose on normal cells, and is thus commonly used in proton radiotherapy. However, because of the high magnetic rigidity of carbon ions, the weight of the rotating gantry for heavy-ion therapy is about three-times heavier than those used for proton cancer therapy, according to our estimation. To overcome this issue, we developed a small and lightweight rotating gantry in collaboration with the National Institute of Radiological Sciences (NIRS). The compact rotating gantry was composed of ten low-temperature superconducting (LTS) magnets that were designed from the viewpoint of beam optics. These LTS magnets have a surface-winding coil-structure and provide both dipole and quadrupole fields. The maximum dipole and quadrupole magnetic field of the magnets were 2.88 T and 9.3 T/m, respectively. The rotating gantry was installed at NIRS, and beam commissioning is in progress to achieve the required beam quality. In the three years since 2013, in a project supported by the Ministry of Economy, Trade and Industry (METI) and the Japan Agency for Medical Research and Development (AMED), we have been developing high-temperature superconducting (HTS) magnets with the aim of a further size reduction of the rotating gantry. To develop fundamental technologies for designing and fabricating HTS magnets, a model magnet was manufactured. The model magnet was composed of 24 saddle-shaped HTS coils and generated a magnetic field of 1.2 T. In the presentation, recent progress in this research will be reported.

The influence of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices

International Nuclear Information System (INIS)

Idris, A; Pullen, K

2013-01-01

The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.

Polarity and Nonpolarity of Ionic Liquids Viewed from the Rotational Dynamics of Carbon Monoxide.

Science.gov (United States)

Yasaka, Y; Kimura, Y

2015-12-17

The rotational dynamics of carbon monoxide (CO) in a molten salt, ionic liquids (ILs), and alkanes were investigated by (17)O NMR T1 measurements using labeled C(17)O. The molten salt and the studied ILs have the bis(trifluoromethanesulfonyl)imide anion ([NTf2](-)) in common. In hexane near room temperature, the rotational relaxation times are close to the values predicted from the slip boundary condition in the Stokes-Einstein-Debye (SED) theory. However, in contradiction to the theoretical prediction, the rotational relaxation times decrease as the value of η/T increases, where η and T are the viscosity and absolute temperature, respectively. In other alkanes and ILs used in this study, the rotational relaxation times are much faster than those predicted by SED, and show a unique dependence on the number of alkyl carbons. For the same value of η/T, the CO rotational relaxation times in ILs composed of short-alkyl-chain-length imidazolium cations (1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium) are close to those for a molten salt (Cs[NTf2]). On the other hand, the rotational relaxation times in ILs composed of long-chain-length imidazolium (1-methyl-3-octylimidazolium) and phosphonium (tributylmethylphosphonium and tetraoctylphosphonium) cations are much shorter than the SED predictions. This deviation from theory increases as the alkyl chain length increases. We also found that the rotational relaxation times in dodecane and squalane are similar to those in ILs with a similar number of alkyl carbons. These results are discussed in terms of heterogeneous solvation and in comparison with the translational diffusion of CO in ILs.

Vib--rotational energy distributions and relaxation processes in pulsed HF chemical lasers

International Nuclear Information System (INIS)

Ben-Shaul, A.; Kompa, K.L.; Schmailzl, U.

1976-01-01

The rate equations governing the temporal evolution of photon densities and level populations in pulsed F+H 2 →HF+H chemical lasers are solved for different initial conditions. The rate equations are solved simultaneously for all relevant vibrational--rotational levels and vibrational--rotational P-branch transitions. Rotational equilibrium is not assumed. Approximate expressions for the detailed state-to-state rate constants corresponding to the various energy transfer processes (V--V, V--R,T, R--R,T) coupling the vib--rotational levels are formulated on the basis of experimental data, approximate theories, and qualitative considerations. The main findings are as follows: At low pressures, R--T transfer cannot compete with the stimulated emission, and the laser output largely reflects the nonequilibrium energy distribution in the pumping reaction. The various transitions reach threshold and decay almost independently and simultaneous lasing on several lines takes place. When a buffer gas is added in excess to the reacting mixture, the enhanced rotational relaxation leads to nearly single-line operation and to the J shift in lasing. Laser efficiency is higher at high inert gas pressures owing to a better extraction of the internal energy from partially inverted populations. V--V exchange enhances lasing from upper vibrational levels but reduces the total pulse intensity. V--R,T processes reduce the efficiency but do not substantially modify the spectral output distribution. The photon yield ranges between 0.4 and 1.4 photons/HF molecule depending on the initial conditions. Comparison with experimental data, when available, is fair

Group-theoretical and topological analysis of localized rotation-vibration states

International Nuclear Information System (INIS)

Sadovskii, D.A.; Zhilinskii, B.I.

1993-01-01

A general scheme of qualitative analysis is applied to molecular rovibrational problems. The classical-quantum correspondence provides a description of different classes of localized quantum rotation-vibration states associated with localized classical motion. A description of qualitative features, such as localized motion, and of qualitative changes, such as localization phenomena, is based on the concept of the simplest Hamiltonian. It uses only the topological properties of the compact reduced phase space and the action of the symmetry group on this space. The qualitative changes of the simplest Hamiltonian are analyzed as bifurcations caused by rotational or vibrational excitation. The relation between the stationary points of the classical Hamiltonian function on the reduced phase space and the principal periodic trajectories in the coordinate space is analyzed for vibrational Hamiltonians. In particular, the relation between the nonlinear normal modes, proposed by Montaldi, Roberts, and Stewart [Philos. Trans. R. Soc. London, Ser. A 325, 237 (1988)], and normal- and local-mode models widely used in molecular physics is discussed. Along with a general consideration of localized rotational and vibrational states a more detailed analysis of the vibrational dynamics of an X 3 molecule with the D 3h symmetry, such as the H 3 + molecular ion, is given

Rotational Spectrum of 1,1-Difluoroethane: Internal Rotation Analysis and Structure

Science.gov (United States)

Villamanan, R. M.; Chen, W. D.; Wlodarczak, G.; Demaison, J.; Lesarri, A. G.; Lopez, J. C.; Alonso, J. L.

1995-05-01

The rotational spectrum of CH3CHF2 in its ground state was measured up to 653 GHz. Accurate rotational and centrifugal distortion constants were determined. The internal rotation splittings were analyzed using the internal axis method. An ab initio structure has been calculated and a near-equilibrium structure has been estimated using offsets derived empirically. This structure was compared to an experimental r0 structure. The four lowest excited states (including the methyl torsion) have also been assigned.

Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

International Nuclear Information System (INIS)

Houry, M.P.; Bourles, H.

1996-01-01

The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this speed is a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band, i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit or rather an islanding. It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms. We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth to the speed measure. If one uses conventional methods to obtain a band stop filter, it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman'a theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a while noise. The resulting Kalman filter is an effective band stop filter, whose phase nicely remains near zero in the whole pass-band. The digital simulations we made and the tests we carried out with the Electricite de France Micro Network laboratory show the advantages of the rotation speed filter we designed using Kalman's theory. With the proposed filter, the speed measure filtering is better in terms of reduction and phase shift. the result is that there are less untimely solicitations of the fast valving system. Consequently, this device improves the power systems stability by minimizing the risks of deep perturbations due to a temporary lack of generation and the risks of under-speed loss

Blade dynamic stress analysis of rotating bladed disks

Directory of Open Access Journals (Sweden)

Kellner J.

2007-10-01

Full Text Available The paper deals with mathematical modelling of steady forced bladed disk vibrations and with dynamic stress calculation of the blades. The blades are considered as 1D kontinuum elastic coupled with three-dimensional elastic disk centrally clamped into rotor rotating with constant angular speed. The steady forced vibrations are generated by the aerodynamic forces acting along the blade length. By using modal synthesis method the mathematical model of the rotating bladed disk is condensed to calculate steady vibrations. Dynamic stress analysis of the blades is based on calculation of the time dependent reduced stress in blade cross-sections by using Hubert-Misses-Hencky stress hypothesis. The presented method is applied to real turbomachinery rotor with blades connected on the top with shroud.

SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

International Nuclear Information System (INIS)

Ranallo, F; Szczykutowicz, T

2014-01-01

Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare

Covariant anomalies and Hawking radiation from charged rotating black strings in anti-de Sitter spacetimes

International Nuclear Information System (INIS)

Peng Junjin; Wu Shuangqing

2008-01-01

Motivated by the success of the recently proposed method of anomaly cancellation to derive Hawking fluxes from black hole horizons of spacetimes in various dimensions, we have further extended the covariant anomaly cancellation method shortly simplified by Banerjee and Kulkarni to explore the Hawking radiation of the (3+1)-dimensional charged rotating black strings and their higher dimensional extensions in anti-de Sitter spacetimes, whose horizons are not spherical but can be toroidal, cylindrical or planar, according to their global identifications. It should be emphasized that our analysis presented here is very general in the sense that the determinant of the reduced (1+1)-dimensional effective metric from these black strings need not be equal to one (√(-g)≠1). Our results indicate that the gauge and energy-momentum fluxes needed to cancel the (1+1)-dimensional covariant gauge and gravitational anomalies are compatible with the Hawking fluxes. Besides, thermodynamics of these black strings are studied in the case of a variable cosmological constant

WE-EF-207-02: The Rotate-Plus-Shift C-Arm Trajectory: Theory and First Clinical Results

International Nuclear Information System (INIS)

Ritschl, L; Kachelriess, M; Kuntz, J

2015-01-01

Purpose: The proposed method enables the acquisition of a complete dataset for 3D reconstruction of C-Arm data using less than 180° rotation. Methods: Typically a C–arm cone–beam CT scan is performed using a circle–like trajectory around a region of interest. Therefore an angular range of at least 180° plus fan–angle must be covered to ensure a completely sampled data set. This fact defines some constraints on the geometry and technical specifications of a C–arm system, for example a larger C radius or a smaller C opening respectively. This is even more important for mobile C-arm devices which are typically used in surgical applications.To overcome these limitations we propose a new trajectory which requires only 180° minusfan–angle of rotation for a complete data set. The trajectory consists of three parts: A rotation of the C around a defined iso–center and two translational movements parallel to the detector plane at the begin and at the end of the rotation (rotate plus shift trajectory). This enables the acquisition of a completely sampled dataset using only 180° minus fan–angle of rotation. Results: For the evaluation of the method we show simulated and measured data. The results show, that the rotate plus shift scan yields equivalent image quality compared to the short scan which is assumed to be the gold standard for C-arm CT today. Compared to the pure rotational scan over only 165°, the rotate plus shift scan shows strong improvements in image quality. Conclusion: The proposed method makes 3D imaging using C–arms with less than 180° rotation range possible. This enables integrating full 3D functionality into a C- arm device without any loss of handling and usability for 2D imaging

When a Slowly Rotating Aquaplanet is Coupled to a Dynamical Ocean

Science.gov (United States)

Salameh, J.; Marotzke, J.

2017-12-01

Planets orbiting in close distance from their stars have a high probability to be detected, and are expected to be slowly rotating due to strong tidal forces. By increasing the rotation period from 1 Earth-day to 365 Earth-days, we previously found that the global-mean surface temperature of an aquaplanet with a static mixed-layer ocean decreases by up to 27 K. The cooling is attributed to an increase of the planetary albedo with the rotation period, which is associated with the different distributions of the sea ice and the deep convective clouds. However, we had there assumed a fixed mixed-layer depth and a zero oceanic heat transport in the aquaplanet configuration. The limitations of these assumptions in such exotic climates are still unclear. We therefore perform coupled atmosphere-ocean aquaplanet simulations with the general circulation model ICON for various rotation periods ranging from 1 Earth-day to 365 Earth-days. We investigate how the underlying oceanic circulation modifies the mean climate of slowly rotating aquaplanets, and whether the day-to-night oceanic heat transport reduces the surface-temperature gradients and the sea-ice extent.

Allocation of synchronous condensers for restoration of system short-circuit power

DEFF Research Database (Denmark)

Marrazi, Emanuel; Yang, Guangya; Weinreich-Jensen, Peter

2017-01-01

Modern power systems, employing an increasing number of converter-based renewable energy sources (RES) and decreasing the usage of conventional power plants, are leading to lower levels of short-circuit power and rotational inertia. A solution to this is the employment of synchronous condensers...... in the grid, in order to provide sufficient short-circuit power. This results in the increase of the short-circuit ratio (SCR) at transmission system bus-bars serving as points of interconnection (POI) to renewable generation. Evaluation of the required capacity and grid-location of the synchronous condensers...... by renewable generation. Total cost of synchronous condenser installations in the system is minimized and the SCRs at the POIs of central renewable power plants are strengthened. The method has potential for application on larger grids, aiding grid-integration of RES....

Intensity modulated operating mode of the rotating gamma system.

Science.gov (United States)

Sengupta, Bishwambhar; Gulyas, Laszlo; Medlin, Donald; Koroknai, Tibor; Takacs, David; Filep, Gyorgy; Panko, Peter; Godo, Bence; Hollo, Tamas; Zheng, Xiao Ran; Fedorcsak, Imre; Dobai, Jozsef; Bognar, Laszlo; Takacs, Endre

2018-05-01

The purpose of this work was to explore two novel operation modalities of the rotating gamma systems (RGS) that could expand its clinical application to lesions in close proximity to critical organs at risk (OAR). The approach taken in this study consists of two components. First, a Geant4-based Monte Carlo (MC) simulation toolkit is used to model the dosimetric properties of the RGS Vertex 360™ for the normal, intensity modulated radiosurgery (IMRS), and speed modulated radiosurgery (SMRS) operation modalities. Second, the RGS Vertex 360™ at the Rotating Gamma Institute in Debrecen, Hungary is used to collect experimental data for the normal and IMRS operation modes. An ion chamber is used to record measurements of the absolute dose. The dose profiles are measured using Gafchromic EBT3 films positioned within a spherical water equivalent phantom. A strong dosimetric agreement between the measured and simulated dose profiles and penumbra was found for both the normal and IMRS operation modes for all collimator sizes (4, 8, 14, and 18 mm diameter). The simulated falloff and maximum dose regions agree better with the experimental results for the 4 and 8 mm diameter collimators. Although the falloff regions align well in the 14 and 18 mm collimators, the maximum dose regions have a larger difference. For the IMRS operation mode, the simulated and experimental dose distributions are ellipsoidal, where the short axis aligns with the blocked angles. Similarly, the simulated dose distributions for the SMRS operation mode also adopt an ellipsoidal shape, where the short axis aligns with the angles where the orbital speed is highest. For both modalities, the dose distribution is highly constrained with a sharper penumbra along the short axes. Dose modulation of the RGS can be achieved with the IMRS and SMRS modes. By providing a highly constrained dose distribution with a sharp penumbra, both modes could be clinically applicable for the treatment of lesions in close

Two dimensional numerical analysis of aerodynamic characteristics for rotating cylinder on concentrated air flow

Science.gov (United States)

Alias, M. S.; Rafie, A. S. Mohd; Marzuki, O. F.; Hamid, M. F. Abdul; Chia, C. C.

2017-12-01

Over the years, many studies have demonstrated the feasibility of the Magnus effect on spinning cylinder to improve lift production, which can be much higher than the traditional airfoil shape. With this characteristic, spinning cylinder might be used as a lifting device for short take-off distance aircraft or unmanned aerial vehicle (UAV). Nonetheless, there is still a gap in research to explain the use of spinning cylinder as a good lifting device. Computational method is used for this study to analyse the Magnus effect, in which two-dimensional finite element numerical analysis method is applied using ANSYS FLUENT software to examine the coefficients of lift and drag, and to investigate the flow field around the rotating cylinder surface body. Cylinder size of 30mm is chosen and several configurations in steady and concentrated air flows have been evaluated. All in all, it can be concluded that, with the right configuration of the concentrated air flow setup, the rotating cylinder can be used as a lifting device for very short take-off since it can produce very high coefficient of lift (2.5 times higher) compared with steady air flow configuration.

LES of turbulent flow in a concentric annulus with rotating outer wall

International Nuclear Information System (INIS)

Hadžiabdić, M.; Hanjalić, K.; Mullyadzhanov, R.

2013-01-01

Highlights: • High rotation up to N = 2 dampens progressively the turbulence near the rotating outer wall. • At 2 2.8, while tending to laminarize, the flow exhibits distinct Taylor-Couette vortical rolls. -- Abstract: Fully-developed turbulent flow in a concentric annulus, r 1 /r 2 = 0.5, Re h = 12,500, with the outer wall rotating at a range of rotation rates N = U θ,wall /U b from 0.5 up to 4 is studied by large-eddy simulations. The focus is on the effects of moderate to very high rotation rates on the mean flow, turbulence statistics and eddy structure. For N up to ∼2, an increase in the rotation rate dampens progressively the turbulence near the rotating outer wall, while affecting only mildly the inner-wall region. At higher rotation rates this trend is reversed: for N = 2.8 close to the inner wall turbulence is dramatically reduced while the outer wall region remains turbulent with discernible helical vortices as the dominant turbulent structure. The turbulence parameters and eddy structures differ significantly for N = 2 and 2.8. This switch is attributed to the centrifuged turbulence (generated near the inner wall) prevailing over the axial inertial force as well as over the counteracting laminarizing effects of the rotating outer wall. At still higher rotation, N = 4, the flow gets laminarized but with distinct spiralling vortices akin to the Taylor–Couette rolls found between the two counter-rotating cylinders without axial flow, which is the limiting case when N approaches to infinity. The ratio of the centrifugal to axial inertial forces, Ta/Re 2 ∝ N 2 (where Ta is the Taylor number) is considered as a possible criterion for defining the conditions for the above regime change

The Effects of Cattle Manure and Garlic Rotation on Soil under Continuous Cropping of Watermelon (Citrullus lanatus L.)

Science.gov (United States)

Liu, Changming; Wang, Yongqi; Ma, Jianxiang; Zhang, Yong; Li, Hao; Zhang, Xian

2016-01-01

Continuous cropping of watermelon (Citrullus lanatus L.) can lead to reduced yield and quality. We aimed to determine the effects of cattle manure addition and rotation with green garlic to improve yield and reduce disease incidence in watermelon and to examine the effects on the biological and chemical characteristics of the soil. Field experiments were performed during 2012–2014 on land previously under two years of continuous watermelon cropping in northwest China. We examined three treatment combinations: watermelon and garlic rotation, cattle manure application before watermelon planting, and combined cattle manure addition and crop rotation. Watermelon monoculture was retained as a control. Watermelon yield was significantly higher and disease incidence was lower in the treatments than the control. The populations of soil bacteria and actinomycetes and the bacteria/fungi ratio increased significantly and soil enzyme activities were generally enhanced under treatments. Available nutrients and soil organic matter contents were much higher under experimental treatments than the control. Results suggest both cattle manure application and garlic rotation can ameliorate the negative effects of continuous cropping. The combined treatment of cattle manure addition and green garlic rotation was optimal to increase yield, reduce disease incidence and enhance soil quality. PMID:27258145

On Job Rotation

OpenAIRE

Metin M. Cosgel; Thomas J. Miceli

1998-01-01

A fundamental principle of economics with which Adam Smith begins The Wealth of Nations is the division of labor. Some firms, however, have been pursuing a practice called job rotation, which assigns each worker not to a single and specific task but to a set of several tasks among which he or she rotates with some frequency. We examine the practice of job rotation as a serious alternative to specialization, with three objectives. The first is to consider current and historical examples of job...

Arthroscopic Repair of Full-Thickness Rotator Cuff Tears With and Without Acromioplasty: Randomized Prospective Trial With 2-Year Follow-up.

Science.gov (United States)

Abrams, Geoffrey D; Gupta, Anil K; Hussey, Kristen E; Tetteh, Elizabeth S; Karas, Vasili; Bach, Bernard R; Cole, Brian J; Romeo, Anthony A; Verma, Nikhil N

2014-06-01

Acromioplasty is commonly performed during arthroscopic rotator cuff repair, but its effect on short-term outcomes is debated. To report the short-term clinical outcomes of patients undergoing arthroscopic repair of full-thickness rotator cuff tears with and without acromioplasty. Randomized controlled trial; Level of evidence, 2. Patients undergoing arthroscopic repair of full-thickness rotator cuff tears were randomized into acromioplasty or nonacromioplasty groups. The Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES) score, Constant score, University of California-Los Angeles (UCLA) score, and Short Form-12 (SF-12) health assessment were collected along with physical examination including range of motion and dynamometer strength testing. Intraoperative data including tear size, repair configuration, and concomitant procedures were recorded. Follow-up examination was performed at regular intervals up to 2 years. Preoperative imaging was reviewed to classify the acromial morphologic type, acromial angle, and lateral acromial angulation. A total of 114 patients were initially enrolled in the study, and 95 (83%; 43 nonacromioplasty, 52 acromioplasty) were available for a minimum 2-year follow-up. There were no significant differences in baseline characteristics, including number of tendons torn, repair configuration, concomitant procedures, and acromion type and angles. Within groups, there was a significant (P < .001) improvement in all functional outcome scores from preoperatively to all follow-up time points, including 2 years, for the nonacromioplasty and acromioplasty groups (ASES score: 55.1-91.5, 48.8-89.0; Constant score: 48.3-75.0, 51.9-78.7, respectively). There were no significant differences in functional outcomes between nonacromioplasty and acromioplasty groups or between subjects with different acromial features at any time point. The results of this study demonstrate no difference in clinical outcomes after rotator cuff repair

Use by small mammals of short-rotation plantations in relation to their structure and isolation

Directory of Open Access Journals (Sweden)

Marta Giordano

2010-06-01

Full Text Available Abstract Over the last decades, dramatic changes in agricultural practices have led to important modifications of land-use, as well as landscape structure, and to a general biodiversity loss in agro-ecosystems. During 2008 we investigated the small mammal communities of Short Rotation Forestry (SRF stands in Northern Italy. We live-trapped small mammals, during summer and autumn, in different types of SRF stands and surrounding habitats and compared capture rates. We evaluated the influence on small mammals abundance of the distance between the stands and other habitats offering woody or bushy cover. Our results showed that SRF plantations are widely exploited by small mammals, especially in autumn and that capture rate is the highest in “double-row” stands. The distance from woods or other arboriculture stands was negatively correlated to small mammals abundance. We conclude that SRF plantations can be considered a suitable habitat for small mammals and may work as a “corridor habitat” between fragmented patches of suitable habitats.
Riassunto Uso degli impianti a turno breve da parte dei micrommamiferi, in relazione alla loro struttura e isolamento Negli ultimi decenni profondi cambiamenti nelle pratiche agricole hanno causato modifiche nella tipologia di uso dei terreni, così come nella struttura del paesaggio, che hanno portato a una generale perdita di biodiversità negli agroecosistemi. Nel corso del 2008 abbiamo studiato le comunità di micromammiferi nelle piantagioni di pioppo per la produzione di biomassa (SRF nel Nord Italia. Con l’uso di live-traps abbiamo effettuato due sessioni di cattura, una estiva e una autunnale, nei diversi tipi di impianto delle SRF e negli ambienti circostanti, per comparare le frequenze di cattura. Abbiamo quindi analizzato l’influenza che la distanza tra i diversi ambienti con copertura arborea ha sull’abbondanza dei micromammiferi

Basis states for the rotational and vibrational limits of nuclear collective motion

International Nuclear Information System (INIS)

Vanagas, V.; Alishauskas, S.; Kalinauskas, R.; Nadzhakov, E.

1980-01-01

Basis states characterized by quantum numbers traditionally used in the rotational and the vibrational limits are treated in an unified way. An explicit basis construction in the Hilbert space of the collective phenomenological nuclear Hamiltonian generalized to six degrees of freedom in both limits is given. This generalization reduces to including an additional degree of freedom allowing to treat both cases within a collective substance of the complete many-body Hilbert space. A group-theoretical approach is applied. From this point of view the problem is reduced to the construction of a set of U(6)-irreducible states labelled by quantum numbers of two special chains of subgroups adapted for the rotational and vibrational limits. In particular, the generalization is more complicated in the case of the chain for the rotational limits. The explicit construction of a basis for both limits is carried out in two steps: 1) construction of the highest weight state for corresponding group irreducible representation - in the case of the rotational limit U(3) and of the vibrational limit O(5); 2) generating a complete set of states by the projection technique. In this framework it is possible to diagonalize a general phenomenological Hamiltonian in cases different from both limits. It is also possible to calculate transition probabilities induced by any physical quantity

Rotating stars in relativity.

Science.gov (United States)

Paschalidis, Vasileios; Stergioulas, Nikolaos

2017-01-01

Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f -modes and r -modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

Rotating preventers

International Nuclear Information System (INIS)

Tangedahl, M.J.; Stone, C.R.

1992-01-01

This paper reports that recent changes in the oil and gas industry and ongoing developments in horizontal and underbalanced drilling necessitated development of a better rotating head. A new device called the rotating blowout preventer (RBOP) was developed by Seal-Tech. It is designed to replace the conventional rotating control head on top of BOP stacks and allows drilling operations to continue even on live (underbalanced) wells. Its low wear characteristics and high working pressure (1,500 psi) allow drilling rig crews to drill safely in slightly underbalanced conditions or handle severe well control problems during the time required to actuate other BOPs in the stack. Drilling with a RBOP allows wellbores to be completely closed in tat the drill floor rather than open as with conventional BOPs

Translational, rotational, vibrational and electron temperatures of a gliding arc discharge

DEFF Research Database (Denmark)

Zhu, Jiajian; Ehn, Andreas; Gao, Jinlong

2017-01-01

, 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO A–X (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring......Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source...... and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH A–X (0...

Heat transfer from rotating finned heat exchangers with different orientation angles

Energy Technology Data Exchange (ETDEWEB)

Tawfik, Adel Abdalla [Suez Canal University, Marine Engineering and Naval Architecture Department, Faculty of Engineering, Port Said (Egypt)

2010-03-15

The local and average heat transfer characteristics of spoke like fins that extend outward from a rotating shaft have been determined experimentally. The experiments encompassed a number of geometrical parameters, including the length and chord of the fins, the number of fins deployed around the circumference of the shaft and the orientation angles of the fin. The experiments cover a wider range of rotational speeds, which varies from 25 up to 2,000 rpm. Three wire heat flux sensors have been used in conjunction with a slip ring apparatus to evaluate the local and average heat transfer coefficients. The output results indicated that, the heat transfer transition on rotating fins occurs at Reynolds number lower than encountered on the stationary rectangular fins in crossflow. In general, with non zero incidence angle, the rotating system acts as a fan and creates axial air motion, which enhance the heat transfer rate. However, the effect of orientation angle reduces with increasing the rotational speed. The Nusselt number data are independent of the number of fins in the circumferential array at high rotational speed and are weakly dependent at low Reynolds numbers. To facilitate the use of the results for design, correlations were developed which represent the fin heat transfer coefficient as a continuous function of the investigated independent parameters. (orig.)

Rotated balance in humans due to repetitive rotational movement

Science.gov (United States)

Zakynthinaki, M. S.; Madera Milla, J.; López Diaz De Durana, A.; Cordente Martínez, C. A.; Rodríguez Romo, G.; Sillero Quintana, M.; Sampedro Molinuevo, J.

2010-03-01

We show how asymmetries in the movement patterns during the process of regaining balance after perturbation from quiet stance can be modeled by a set of coupled vector fields for the derivative with respect to time of the angles between the resultant ground reaction forces and the vertical in the anteroposterior and mediolateral directions. In our model, which is an adaption of the model of Stirling and Zakynthinaki (2004), the critical curve, defining the set of maximum angles one can lean to and still correct to regain balance, can be rotated and skewed so as to model the effects of a repetitive training of a rotational movement pattern. For the purposes of our study a rotation and a skew matrix is applied to the critical curve of the model. We present here a linear stability analysis of the modified model, as well as a fit of the model to experimental data of two characteristic "asymmetric" elite athletes and to a "symmetric" elite athlete for comparison. The new adapted model has many uses not just in sport but also in rehabilitation, as many work place injuries are caused by excessive repetition of unaligned and rotational movement patterns.

Enhancing Friction Stir Weldability of 6061-T6 Al and AZ31B Mg Alloys Assisted by External Non-rotational Shoulder

Science.gov (United States)

Ji, Shude; Huang, Ruofei; Meng, Xiangchen; Zhang, Liguo; Huang, Yongxian

2017-05-01

In order to increase cooling rate and then reduce the amounts of intermetallic compounds, external non-rotational shoulder tool system derived from traditional tool in friction stir welding was used to join dissimilar Al and Mg alloys. In this study, based on the external non-rotational shoulder, the weldability of Al and Mg alloys was significantly improved. The non-rotational shoulder tool is propitious to make more materials into weld, increase cooling rate and then reduce material adhesion of rotational pin, obtaining sound joint with smaller flashes and smooth surface. Importantly, the thickness of intermetallic compounds layer is reduced compared with traditional tool. Meanwhile, hardness values of dissimilar joint present uneven distribution, resulting from complex intercalated structures in nugget zone (NZ) featured by intermetallic compound layers and fine recrystallized Mg and Al grains. Compared with traditional tool, non-rotational shoulder is beneficial to higher tensile properties of joint. Due to the intermetallic compound layer formed in the interface of Al-Mg, the welding joint easily fractures at the NZ, presenting the typical brittle fracture mode.